text:
The global atmospheric electrical circuit and climate
Harrison, R G
Evidence is emerging for physical links among clouds, global temperatures, the global atmospheric electrical circuit and cosmic ray ionisation. The global circuit extends throughout the atmosphere from the planetary surface to the lower layers of the ionosphere. Cosmic rays are the principal source of atmospheric ions away from the continental boundary layer: the ions formed permit a vertical conduction current to flow in the fair weather part of the global circuit. Through the (inverse) solar modulation of cosmic rays, the resulting columnar ionisation changes may allow the global circuit to convey a solar influence to meteorological phenomena of the lower atmosphere. Electrical effects on non-thunderstorm clouds have been proposed to occur via the ion-assisted formation of ultrafine aerosol, which can grow to sizes able to act as cloud condensation nuclei, or through the increased ice nucleation capability of charged aerosols. Even small atmospheric electrical modulations on the aerosol size distribution ca...
The atmospheric electric global circuit. [thunderstorm activity
Kasemir, H. W.
The hypothesis that world thunderstorm activity represents the generator for the atmospheric electric current flow in the earth atmosphere between ground and the ionosphere is based on a close correlation between the magnitude and the diurnal variation of the supply current (thunderstorm generator current) and the load current (fair weather air-earth current density integrated over the earth surface). The advantages of using lightning survey satellites to furnish a base for accepting or rejecting the thunderstorm generator hypothesis are discussed.
Comment on 'Current Budget of the Atmospheric Electric Global Circuit'
Driscoll, Kevin T.; Blakeslee, Richard J.
In this paper, three major issues relevant to Kasemir's new model will be addressed. The first concerns Kasemir's assertion that there are significant differences between the potentials associated with the new model and the conventional model. A recalculation of these potentials reveals that both models provide equivalent results for the potential difference between the Earth and ionosphere. The second issue to be addressed is Kasemir's assertion that discrepancies in the electric potentials associated with both models can be attributed to modeling the Earth as a sphere, instead of as a planar surface. A simple analytical comparison will demonstrate that differences in the equations for the potentials of the atmosphere derived with a spherical and a planar Earth are negligible for applications to global current flow. Finally, the third issue to be discussed is Kasemir's claim that numerous aspects of the conventional model are incorrect, including the role of the ionosphere in global current flow as well as the significance of cloud-to-ground lightning in supplying charge to the global circuit. In order to refute these misconceptions, it will be shown that these aspects related to the flow of charge in the atmosphere are accurately described by the conventional model of the global circuit.
Atmospheric Electric Field measurements at Eastern North Atlantic ARM Climate Research Facility: Global Electric Circuit Evolution
Lopes, Francisco; Silva, Hugo; Nitschke, Kim; Azevedo, Eduardo
The Eastern North Atlantic (ENA) facility of the ARM programme (established an supported by the U.S. Department of Energy with the collaboration of the local government and University of the Azores), is located at Graciosa Island of the Azores Archipelago (39° N; 28° W). It constitutes a strategic observatory for Atmospheric Electricity since it is located in the Atlantic Ocean basin exposed to clean marine aerosol conditions which reduces the well known spectral signature of atmospheric pollution and enables the study of the so called Global Electrical Circuit (GEC). First evidences of the existence of a GEC affecting the Earth's Electric Environment has retrieved by the Carnegie cruise expedition, in what became known as the Carnegie Curve. Those measurements were made in the Ocean in several campaigns and the present studies aims at reconsidering measurements in similar conditions but in a long-term basis, at least 5 years. This will contribute to the understanding of the long-term evolution of the Ionospheric Potential (IP). In literature there is theoretical evidence that it is decreasing IP in strength, but that conjecture is still lacking valid experimental evidence. Moreover, to clearly identify the GEC signal two effects must be taken into account: the effect of surface radon gas variation, because the Azores Archipelago is a seismic active region the possible influence of Earthquakes cannot be discarded easily; the effect of short-term solar activity on the Atmospheric Electricity modulation, solar flares emitting solar particles (e.g., solar energetic protons) need to be considered in this study.
Brief communication: Earthquake–cloud coupling through the global atmospheric electric circuit
Directory of Open Access Journals (Sweden)
R. G. Harrison
Full Text Available We illustrate how coupling could occur between surface air and clouds via the global electric circuit – through Atmospheric Lithosphere–Ionosphere Charge Exchange (ALICE processes – in an attempt to develop physical understanding of possible relationships between earthquakes and clouds.
Chalmers, J Alan
Atmospheric Electricity brings together numerous studies on various aspects of atmospheric electricity. This book is composed of 13 chapters that cover the main problems in the field, including the maintenance of the negative charge on the earth and the origin of the charges in thunderstorms. After a brief overview of the historical developments of atmospheric electricity, this book goes on dealing with the general principles, results, methods, and the MKS system of the field. The succeeding chapters are devoted to some aspects of electricity in the atmosphere, such as the occurrence and d
REA, Editors of
REA's Essentials provide quick and easy access to critical information in a variety of different fields, ranging from the most basic to the most advanced. As its name implies, these concise, comprehensive study guides summarize the essentials of the field covered. Essentials are helpful when preparing for exams, doing homework and will remain a lasting reference source for students, teachers, and professionals. Electric Circuits I includes units, notation, resistive circuits, experimental laws, transient circuits, network theorems, techniques of circuit analysis, sinusoidal analysis, polyph
Electrical Circuits and Water Analogies
Smith, Frederick A.; Wilson, Jerry D.
Briefly describes water analogies for electrical circuits and presents plans for the construction of apparatus to demonstrate these analogies. Demonstrations include series circuits, parallel circuits, and capacitors. (GS)
The Changing Global Atmospheric Electric Circuit as a Way of Causing Space Weather Effects on Middle Atmosphere Electrodynamic and Thermodynamic Parameters
Makarova, L.; Shirochkov, A.
So far the solar wind energy contribution to energetic balance of the middle atmosphere was ignored in any climatic research. However the solar wind is a permanent source of electromagnetic energy constantly supplied to the near-Earth space and its role is evaluated properly in magnetospheric and ionospheric (to lesser extent) studies. We made extensive studies of the direct solar wind influence on the thermodynamic features of the middle atmosphere by analyzing data of the rocket and balloon sounding. Data of many stations covering latitudinal belt 80o N-55o N and 90o S-65o S- were used. It was found that the stratospheric temperature closely correlated with the solar wind energy expressed as the subsolar distance between the Earth and magnetopause. The best coupling between these two parameters (r>0,8) was obtained for altitudes 22-26 km with decreasing (but meaningful) coupling up and dawn from these heights. Similar dependence between this space parameter and ozone density in its stratospheric maximum was obtained also. As a very important factor a strong (r=0,78) coupling between magnetopause position and magnitude of atmospheric electric field measured by high-altitude balloons above South P leo Station must be mentioned. All these findings allowed us to propose concept of the global electric circuit as a physical mechanism for explanation of a direct coupling between the solar wind and the middle atmosphere. We suggest a new, modified version of the circuit where an external Electro-motive Force generator driven by the solar wind energy is located at dayside magnetopause. The passive elements of this circuit are the ionospheric Elayer (external element of previous version of the- circuit), stratospheric conducting layer of heavy ions (h=20-25 km) and conducting layer of the Earth surface. In this configuration a previous scheme of the global electric circuit is a part of the proposed version of it. The changes of stratospheric temperature could be explained
Positive fractional linear electrical circuits
Kaczorek, Tadeusz
The positive fractional linear systems and electrical circuits are addressed. New classes of fractional asymptotically stable and unstable electrical circuits are introduced. The Caputo and Riemann-Liouville definitions of fractional derivatives are used to analysis of the positive electrical circuits composed of resistors, capacitors, coils and voltage (current) sources. The positive fractional electrical and specially unstable different types electrical circuits are analyzed. Some open problems are formulated.
Electric circuits problem solver
REA, Editors of
Each Problem Solver is an insightful and essential study and solution guide chock-full of clear, concise problem-solving gems. All your questions can be found in one convenient source from one of the most trusted names in reference solution guides. More useful, more practical, and more informative, these study aids are the best review books and textbook companions available. Nothing remotely as comprehensive or as helpful exists in their subject anywhere. Perfect for undergraduate and graduate studies.Here in this highly useful reference is the finest overview of electric circuits currently av
A 3-D RBF-FD elliptic solver for irregular boundaries: modeling the atmospheric global electric circuit with topography
Directory of Open Access Journals (Sweden)
V. Bayona
Full Text Available A numerical model based on Radial Basis Function-generated Finite Differences (RBF-FD is developed for simulating the Global Electric Circuit (GEC within the Earth's atmosphere, represented by a 3-D variable coefficient linear elliptic PDE in a spherically-shaped volume with the lower boundary being the Earth's topography and the upper boundary a sphere at 60 km. To our knowledge, this is (1 the first numerical model of the GEC to combine the Earth's topography with directly approximating the differential operators in 3-D space, and related to this (2 the first RBF-FD method to use irregular 3-D stencils for discretization to handle the topography. It benefits from the mesh-free nature of RBF-FD, which is especially suitable for modeling high-dimensional problems with irregular boundaries. The RBF-FD elliptic solver proposed here makes no limiting assumptions on the spatial variability of the coefficients in the PDE (i.e. the conductivity profile, the right hand side forcing term of the PDE (i.e. distribution of current sources or the geometry of the lower boundary.
Fair weather terrestrial atmospheric electricity
Harrison, G.
Atmospheric electricity is one of the oldest experimental topics in atmospheric science. The fair weather aspects, although having less dramatic effects than thunderstorm electrification, link the microscale behaviour of ion clusters to currents flowing on the global scale. This talk will include a survey of some past measurements and measurement methods, as atmospheric electrical data from a variety of sites and eras are now being used to understand changes in atmospheric composition. Potential Gradient data was the original source of information on the global atmospheric electrical circuit, and similar measurements can now be used to reconstruct past air pollution concentrations, and black carbon loading.
A Global Electric Circuit on Mars
Delory, G. T.; Farrell, W. M.; Desch, M. D.
We describe conditions on the surface of Mars conducive to the formation of a martian global electric circuit, in a direct analogy to the terrestrial case where atmospheric currents and electric fields are generated worldwide through the charging in thunderstorms. Additional information is contained in the original extended abstract.
Electric circuit theory applied electricity and electronics
Yorke, R
Electric Circuit Theory provides a concise coverage of the framework of electrical engineering. Comprised of six chapters, this book emphasizes the physical process of electrical engineering rather than abstract mathematics. Chapter 1 deals with files, circuits, and parameters, while Chapter 2 covers the natural and forced response of simple circuit. Chapter 3 talks about the sinusoidal steady state, and Chapter 4 discusses the circuit analysis. The fifth chapter tackles frequency response of networks, and the last chapter covers polyphase systems. This book will be of great help to electrical
Variational integrators for electric circuits
Ober-Blöbaum, Sina; Cheng, Mulin; Owhadi, Houman; Marsden, Jerrold E
In this contribution, we develop a variational integrator for the simulation of (stochastic and multiscale) electric circuits. When considering the dynamics of an electrical circuit, one is faced with three special situations: 1. The system involves external (control) forcing through external (controlled) voltage sources and resistors. 2. The system is constrained via the Kirchhoff current (KCL) and voltage laws (KVL). 3. The Lagrangian is degenerate. Based on a geometric setting, an appropriate variational formulation is presented to model the circuit from which the equations of motion are derived. A time-discrete variational formulation provides an iteration scheme for the simulation of the electric circuit. Dependent on the discretization, the intrinsic degeneracy of the system can be canceled for the discrete variational scheme. In this way, a variational integrator is constructed that gains several advantages compared to standard integration tools for circuits; in particular, a comparison to BDF methods ...
New model simulations of the global atmospheric electric circuit driven by thunderstorms and electrified shower clouds: The roles of lightning and sprites
DEFF Research Database (Denmark)
Rycroft, Michael J.; Odzimek, Anna; Arnold, Neil F.;
Several processes acting below, in and above thunderstorms and in electrified shower clouds drive upward currents which close through the global atmospheric electric circuit, These are all simulated in a novel way using the software package PSpice. A moderate negative cloud-to-ground lightning...... cloud-to-ground lightning discharge from the bottom of a thunderstorm decreases the ionospheric potential by 0.014%. Such a discharge may trigger a sprite, causing the ionospheric potential to decrease by similar to 1 V. The time scales for the recovery of the ionospheric potential are shown...... to be similar to 250 s, which is of the same order as the CR time constant for the global circuit. Knowing the global average rate of lightning discharges, it is found that negative cloud-to-ground discharges increase the ionospheric potential by only similar to 4%, and that positive cloud-to-ground discharges...
Planetary Atmospheric Electricity
Leblanc, F; Yair, Y; Harrison, R. G; Lebreton, J. P; Blanc, M
This volume presents our contemporary understanding of atmospheric electricity at Earth and in other solar system atmospheres. It is written by experts in terrestrial atmospheric electricity and planetary scientists. Many of the key issues related to planetary atmospheric electricity are discussed. The physics presented in this book includes ionisation processes in planetary atmospheres, charge generation and separation, and a discussion of electromagnetic signatures of atmospheric discharges. The measurement of thunderstorms and lightning, including its effects and hazards, is highlighted by articles on ground and space based instrumentation, and new missions.Theory and modelling of planetary atmospheric electricity complete this review of the research that is undertaken in this exciting field of space science. This book is an essential research tool for space scientists and geoscientists interested in electrical effects in atmospheres and planetary systems. Graduate students and researchers who are new to t...
Electrical circuit theory and technology
Bird, John
This much-loved textbook explains the principles of electrical circuit theory and technology so that students of electrical and mechanical engineering can master the subject. Real-world situations and engineering examples put the theory into context. The inclusion of worked problems with solutions help you to learn and further problems then allow you to test and confirm you have fully understood each subject. In total the book contains 800 worked problems, 1000 further problems and 14 revision tests with answers online. This an ideal text for foundation and undergraduate degree students and those on upper level vocational engineering courses, in particular electrical and mechanical. It provides a sound understanding of the knowledge required by technicians in fields such as electrical engineering, electronics and telecommunications. This edition has been updated with developments in key areas such as semiconductors, transistors, and fuel cells, along with brand new material on ABCD parameters and Fourier's An...
Fractional linear systems and electrical circuits
Kaczorek, Tadeusz
This monograph covers some selected problems of positive and fractional electrical circuits composed of resistors, coils, capacitors and voltage (current) sources. The book consists of 8 chapters, 4 appendices and a list of references. Chapter 1 is devoted to fractional standard and positive continuous-time and discrete-time linear systems without and with delays. In chapter 2 the standard and positive fractional electrical circuits are considered and the fractional electrical circuits in transient states are analyzed. Descriptor linear electrical circuits and their properties are investigated in chapter 3, while chapter 4 is devoted to the stability of fractional standard and positive linear electrical circuits. The reachability, observability and reconstructability of fractional positive electrical circuits and their decoupling zeros are analyzed in chapter 5. The fractional linear electrical circuits with feedbacks are considered in chapter 6. In chapter 7 solutions of minimum energy control for standa...
Relaxation Based Electrical Simulation for VLSI Circuits
Directory of Open Access Journals (Sweden)
S. Rajkumar
Full Text Available Electrical circuit simulation was one of the first CAD tools developed for IC design. The conventional circuit simulators like SPICE and ASTAP were designed initially for the cost effective analysis of circuits containing a few hundred transistors or less. A number of approaches have been used to improve the performances of congenital circuit simulators for the analysis of large circuits. Thereafter relaxation methods was proposed to provide more accurate waveforms than standard circuit simulators with up to two orders of magnitude speed improvement for large circuits. In this paper we have tried to highlights recently used waveform and point relaxation techniques for simulation of VLSI circuits. We also propose a simple parallelization technique and experimentally demonstrate that we can solve digital circuits with tens of million transistors in a few hours.
30 CFR 75.518 - Electric equipment and circuits; overload and short circuit protection.
... Equipment-General § 75.518 Electric equipment and circuits; overload and short circuit protection. Automatic... electric equipment and circuits against short circuit and overloads. Three-phase motors on all electric... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Electric equipment and circuits; overload...
On equivalent resistance of electrical circuits
Kagan, Mikhail
While the standard (introductory physics) way of computing the equvalent resistance of non-trivial electrical ciruits is based on Kirchhoff's rules, there is a mathematically and conceptually simpler approach, called the method of nodal potentials, whose basic variables are the values of electric potential at the circuit's nodes. In this paper, we review the method of nodal potentials and illustrate it using the Wheatstone bridge as an example. At the end, we derive - in a closed form - the equivalent resistance of a generic circuit, which we apply to a few sample circuits. The final result unveils a curious interplay between electrical circuits, matrix algebra, and graph theory and its applications to computer science. The paper is written at a level accessible by undergraduate students who are familiar with matrix arithmetic. For the more inquisitive reader, additional proofs and technical details are provided in the appendix.
Chemical Detection using Electrically Open Circuits having no Electrical Connections
Woodward, Stanley E.; Olgesby, Donald M.; Taylor, Bryant D.; Shams, Qamar A.
This paper presents investigations to date on chemical detection using a recently developed method for designing, powering and interrogating sensors as electrically open circuits having no electrical connections. In lieu of having each sensor from a closed circuit with multiple electrically connected components, an electrically conductive geometric pattern that is powered using oscillating magnetic fields and capable of storing an electric field and a magnetic field without the need of a closed circuit or electrical connections is used. When electrically active, the patterns respond with their own magnetic field whose frequency, amplitude and bandwidth can be correlated with the magnitude of the physical quantities being measured. Preliminary experimental results of using two different detection approaches will be presented. In one method, a thin film of a reactant is deposited on the surface of the open-circuit sensor. Exposure to a specific targeted reactant shifts the resonant frequency of the sensor. In the second method, a coating of conductive material is placed on a thin non-conductive plastic sheet that is placed over the surface of the sensor. There is no physical contact between the sensor and the electrically conductive material. When the conductive material is exposed to a targeted reactant, a chemical reaction occurs that renders the material non-conductive. The change in the material s electrical resistance within the magnetic field of the sensor alters the sensor s response bandwidth and amplitude, allowing detection of the reaction without having the reactants in physical contact with the sensor.
Demonstrating Boolean Logic Using Simple Electrical Circuits
McElhaney, Kevin W.
While exploring the subject of geometric proofs, boolean logic operators AND and OR can be used to allow students to visualize their true-or-false patterns. An activity in the form of constructing electrical circuits is illustrated to explain the concept.
Compact atmospheric pressure plasma self-resonant drive circuits
International Nuclear Information System (INIS)
This paper reports on compact solid-state self-resonant drive circuits that are specifically designed to drive an atmospheric pressure plasma jet and a parallel-plate dielectric barrier discharge of small volume (0.5 cm3). The atmospheric pressure plasma (APP) device can be operated with helium, argon or a mixture of both. Equivalent electrical models of the self-resonant drive circuits and discharge are developed and used to estimate the plasma impedance, plasma power density, current density or electron number density of three APP devices. These parameters and the kinetic gas temperature are dependent on the self-resonant frequency of the APP device. For a fixed switching frequency and APP device geometry, the plasma parameters are controlled by adjusting the dc voltage at the primary coil and the gas flow rate. The resonant frequency is controlled by the selection of the switching power transistor and means of step-up voltage transformation (ferrite core, flyback transformer, or Tesla coil). The flyback transformer operates in the tens of kHz, the ferrite core in the hundreds of kHz and Tesla coil in the MHz range. Embedded within this work is the principle of frequency pulling which is exemplified in the flyback transformer circuit that utilizes a pickup coil for feedback control of the switching frequency. (paper)
Compact atmospheric pressure plasma self-resonant drive circuits
Law, V. J.; Anghel, S. D.
This paper reports on compact solid-state self-resonant drive circuits that are specifically designed to drive an atmospheric pressure plasma jet and a parallel-plate dielectric barrier discharge of small volume (0.5 cm3). The atmospheric pressure plasma (APP) device can be operated with helium, argon or a mixture of both. Equivalent electrical models of the self-resonant drive circuits and discharge are developed and used to estimate the plasma impedance, plasma power density, current density or electron number density of three APP devices. These parameters and the kinetic gas temperature are dependent on the self-resonant frequency of the APP device. For a fixed switching frequency and APP device geometry, the plasma parameters are controlled by adjusting the dc voltage at the primary coil and the gas flow rate. The resonant frequency is controlled by the selection of the switching power transistor and means of step-up voltage transformation (ferrite core, flyback transformer, or Tesla coil). The flyback transformer operates in the tens of kHz, the ferrite core in the hundreds of kHz and Tesla coil in the MHz range. Embedded within this work is the principle of frequency pulling which is exemplified in the flyback transformer circuit that utilizes a pickup coil for feedback control of the switching frequency.
Lord Kelvin's atmospheric electricity measuremnets
Aplin, K L
Lord Kelvin (William Thomson) made important contributions to the study of atmospheric electricity during a brief but productive period from 1859-1861. By 1859 Kelvin had recognised the need for "incessant recording" of atmospheric electrical parameters, and responded by inventing both the water-dropper instrument for measuring the atmospheric Potential Gradient (PG), and photographic data logging. The water-dropper was widely adopted internationally and is still in use today. Following theoretical considerations of electric field distortion by local topography, Kelvin developed a portable electrometer, using it to investigate PG on the Scottish island of Arran. During these environmental measurements, Kelvin may have unwittingly detected atmospheric PG changes during solar activity in August/September 1859 associated with the "Carrington event". Kelvin's atmospheric electricity work presents an early representative study in quantitative environmental physics, through the application of mathematical principle...
30 CFR 57.4011 - Abandoned electric circuits.
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Abandoned electric circuits. 57.4011 Section 57.4011 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... and Control § 57.4011 Abandoned electric circuits. Abandoned electric circuits shall be...
30 CFR 56.4011 - Abandoned electric circuits.
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Abandoned electric circuits. 56.4011 Section 56.4011 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... Control § 56.4011 Abandoned electric circuits. Abandoned electric circuits shall be deenergized...
30 CFR 77.500 - Electric power circuits and electric equipment; deenergization.
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Electric power circuits and electric equipment... OF UNDERGROUND COAL MINES Electrical Equipment-General § 77.500 Electric power circuits and electric equipment; deenergization. Power circuits and electric equipment shall be deenergized before work is done...
Fractional RC and LC Electrical Circuits
Directory of Open Access Journals (Sweden)
Gómez-Aguilar José Francisco
Full Text Available In this paper we propose a fractional differential equation for the electrical RC and LC circuit in terms of the fractional time derivatives of the Caputo type. The order of the derivative being considered is 0 < ɣ ≤1. To keep the dimensionality of the physical parameters R, L, C the new parameter σ is introduced. This parameter characterizes the existence of fractional structures in the system. A relation between the fractional order time derivative ɣ and the new parameter σ is found. The numeric Laplace transform method was used for the simulation of the equations results. The results show that the fractional differential equations generalize the behavior of the charge, voltage and current depending of the values of ɣ. The classical cases are recovered by taking the limit when ɣ = 1. An analysis in the frequency domain of an RC circuit shows the application and use of fractional order differential equations.
29 CFR 1915.181 - Electrical circuits and distribution boards.
... employee is permitted to work on an electrical circuit, except when the circuit must remain energized for testing and adjusting, the circuit shall be deenergized and checked at the point at which the work is to be done to insure that it is actually deenergized. When testing or adjusting an energized circuit...
How Young Children Understand Electric Circuits: Prediction, Explanation and Exploration
Glauert, Esme Bridget
This paper reports findings from a study of young children's views about electric circuits. Twenty-eight children aged 5 and 6 years were interviewed. They were shown examples of circuits and asked to predict whether they would work and explain why. They were then invited to try out some of the circuit examples or make circuits of their own…
30 CFR 75.509 - Electric power circuit and electric equipment; deenergization.
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Electric power circuit and electric equipment... LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Electrical Equipment-General § 75.509 Electric power circuit and electric equipment; deenergization. All power circuits...
30 CFR 77.506 - Electric equipment and circuits; overload and short-circuit protection.
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Electric equipment and circuits; overload and short-circuit protection. 77.506 Section 77.506 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... WORK AREAS OF UNDERGROUND COAL MINES Electrical Equipment-General § 77.506 Electric equipment...
Performance analysis of electrical circuits /PANE/
Johnson, K. L.; Steinberg, L. L.
Automated statistical and worst case computer program has been designed to perform dc and ac steady circuit analyses. The program determines the worst case circuit performance by solving circuit equations.
49 CFR 236.308 - Mechanical or electric locking or electric circuits; requisites.
... 49 Transportation 4 2010-10-01 2010-10-01 false Mechanical or electric locking or electric..., AND APPLIANCES Interlocking Standards § 236.308 Mechanical or electric locking or electric circuits; requisites. Mechanical or electric locking or electric circuits shall be installed to prevent signals...
The Elusive Memristor: Properties of Basic Electrical Circuits
Joglekar, Yogesh N.; Wolf, Stephen J.
We present an introduction to and a tutorial on the properties of the recently discovered ideal circuit element, a memristor. By definition, a memristor M relates the charge "q" and the magnetic flux [phi] in a circuit and complements a resistor R, a capacitor C and an inductor L as an ingredient of ideal electrical circuits. The properties of…
Market price simulator based on analog electrical circuit
Aki-Hiro Sato; Hideki Takayasu
We constructed an analog electrical circuit which generates fluctuations in which probability density function has power law tails. In the circuit fluctuations with an arbitrary exponent of the power law can be obtained by adjusting the resistance. With this low cost circuit the random fluctuations which have the similar statistics to foreign exchang rates can be generated as fast as an expensive digital computer.
Device, system and method for a sensing electrical circuit
Vranish, John M. (Inventor)
The invention relates to a driven ground electrical circuit. A driven ground is a current-measuring ground termination to an electrical circuit with the current measured as a vector with amplification. The driven ground module may include an electric potential source V.sub.S driving an electric current through an impedance (load Z) to a driven ground. Voltage from the source V.sub.S excites the minus terminal of an operational amplifier inside the driven ground which, in turn, may react by generating an equal and opposite voltage to drive the net potential to approximately zero (effectively ground). A driven ground may also be a means of passing information via the current passing through one grounded circuit to another electronic circuit as input. It may ground one circuit, amplify the information carried in its current and pass this information on as input to the next circuit.
Secondary School Students' Misconceptions about Simple Electric Circuits
Küçüközer, Hüseyin; Kocakülah, Sabri
The aim of this study is to reveal secondary school students' misconceptions about simple electric circuits and to define whether specific misconceptions peculiar to Turkish students exist within those identified. Data were obtained with a conceptual understanding test for simple electric circuits and semi-structured interviews. Conceptual…
Electric circuit model for strained-layer epitaxy
Kujofsa, Tedi; Ayers, John E.
For the design and analysis of a strained-layer semiconductor device structure, the equilibrium strain profile may be determined numerically by energy minimization but this method is computationally intense and non-intuitive. Here we present an electric circuit model approach for the equilibrium analysis of an epitaxial stack, in which each sublayer may be represented by an analogous configuration involving a current source, a resistor, a voltage source, and an ideal diode. The resulting node voltages in the analogous electric circuit correspond to the equilibrium strains in the original epitaxial structure. This new approach enables analysis using widely accessible circuit simulators, and an intuitive understanding of electric circuits may be translated to the relaxation of strained-layer structures. In this paper, we describe the mathematical foundation of the electrical circuit model and demonstrate its application to epitaxial layers of Si1‑x Ge x grown on a Si (001) substrate.
The elusive memristor: properties of basic electrical circuits
Joglekar, Yogesh N.; Wolf, Stephen J.
We present a tutorial on the properties of the new ideal circuit element, a memristor. By definition, a memristor M relates the charge q and the magnetic flux $\\phi$ in a circuit, and complements a resistor R, a capacitor C, and an inductor L as an ingredient of ideal electrical circuits. The properties of these three elements and their circuits are a part of the standard curricula. The existence of the memristor as the fourth ideal circuit element was predicted in 1971 based on symmetry argu...
Chapter 12: Trapped Electrons as Electrical (Quantum) Circuits
Verdú, José
In this chapter, we present a detailed model of the equivalent electric circuit of a single trapped particle in a coplanar-waveguide (CPW) Penning trap. The CPW-trap, which is essentially a section of coplanar-waveguide transmission-line, is designed to make it compatible with circuit-quantum electrodynamic architectures. This will enable a single trapped electron, or geonium atom, as a potential building block of microwave quantum circuits. The model of the trapped electron as an electric circuit was first introduced by Hans Dehmelt in the 1960s. It is essential for the description of the electronic detection using resonant tank circuits. It is also the basis for the description of the interaction of a geonium atom with other distant quantum systems through electrical (microwave) signals.
30 CFR 77.506-1 - Electric equipment and circuits; overload and short circuit protection; minimum requirements.
...-1 Electric equipment and circuits; overload and short circuit protection; minimum requirements... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Electric equipment and circuits; overload and short circuit protection; minimum requirements. 77.506-1 Section 77.506-1 Mineral Resources MINE...
The elusive memristor: properties of basic electrical circuits
Joglekar, Yogesh N.; Wolf, Stephen J.
We present an introduction to and a tutorial on the properties of the recently discovered ideal circuit element, a memristor. By definition, a memristor M relates the charge q and the magnetic flux phi in a circuit and complements a resistor R, a capacitor C and an inductor L as an ingredient of ideal electrical circuits. The properties of these three elements and their circuits are a part of the standard curricula. The existence of the memristor as the fourth ideal circuit element was predicted in 1971 based on symmetry arguments, but was clearly experimentally demonstrated just last year. We present the properties of a single memristor, memristors in series and parallel, as well as ideal memristor-capacitor (MC), memristor-inductor (ML) and memristor-capacitor-inductor (MCL) circuits. We find that the memristor has hysteretic current-voltage characteristics. We show that the ideal MC (ML) circuit undergoes non-exponential charge (current) decay with two time scales and that by switching the polarity of the capacitor, an ideal MCL circuit can be tuned from overdamped to underdamped. We present simple models which show that these unusual properties are closely related to the memristor's internal dynamics. This tutorial complements the pedagogy of ideal circuit elements (R, C and L) and the properties of their circuits, and is aimed at undergraduate physics and electrical engineering students.
The elusive memristor: properties of basic electrical circuits
Energy Technology Data Exchange (ETDEWEB)
Joglekar, Yogesh N; Wolf, Stephen J [Department of Physics, Indiana University Purdue University Indianapolis, Indianapolis, IN 46202 (United States)], E-mail: email@example.com
We present an introduction to and a tutorial on the properties of the recently discovered ideal circuit element, a memristor. By definition, a memristor M relates the charge q and the magnetic flux {phi} in a circuit and complements a resistor R, a capacitor C and an inductor L as an ingredient of ideal electrical circuits. The properties of these three elements and their circuits are a part of the standard curricula. The existence of the memristor as the fourth ideal circuit element was predicted in 1971 based on symmetry arguments, but was clearly experimentally demonstrated just last year. We present the properties of a single memristor, memristors in series and parallel, as well as ideal memristor-capacitor (MC), memristor-inductor (ML) and memristor-capacitor-inductor (MCL) circuits. We find that the memristor has hysteretic current-voltage characteristics. We show that the ideal MC (ML) circuit undergoes non-exponential charge (current) decay with two time scales and that by switching the polarity of the capacitor, an ideal MCL circuit can be tuned from overdamped to underdamped. We present simple models which show that these unusual properties are closely related to the memristor's internal dynamics. This tutorial complements the pedagogy of ideal circuit elements (R, C and L) and the properties of their circuits, and is aimed at undergraduate physics and electrical engineering students.
Shuttle Electrical Power Analysis Program (SEPAP) distribution circuit analysis report
Torina, E. M.
An analysis and evaluation was made of the operating parameters of the shuttle electrical power distribution circuit under load conditions encountered during a normal Sortie 2 Mission with emphasis on main periods of liftoff and landing.
Hamilton´s Principle and Electric Circuits Tudory
Daniel Mayer
In the theory of electrical or electromechanical circuits different methods are known for construction of mathematical model. In this paper another, alternative method is introduced that is based on Hamilton variational principle that is generally valid in physics.
Lower Atmospheric Electric Field due to Cloud Charge Distribution
Paul, Suman; Haldar, Dilip kumar; Sundar De, Syam; Ghosh, Abhijit; Hazra, Pranab; Bandyopadhyay, Bijoy
The distributions of electric charge in the electrified clouds introduce important effects in the ionosphere and into the region between the ionosphere and the Earth. The electrical properties of the medium are changed greatly between thundercloud altitudes and the magnetosphere. A model for the penetration of DC thundercloud electric field between the Earth's upper and lower atmosphere has been presented here. The model deals with the electromagnetic responses of the atmosphere simulated through Maxwell's equations together with a time-varying source charge distribution. The modified ellipsoidal-Gaussian profile has been taken for the charge distribution of the electrified cloud. The conductivity profile of the medium is taken to be isotropic below 70 km height and anisotropic above 70 km. The Earth's surface is considered to be perfectly conducting. A general form of equation representing the thundercloud electric field component is deduced. In spite of assumptions for axial symmetry of thundercloud charge distribution considered in the model, the results are obtained giving the electric field variation in the upper atmosphere. The vertical component of the electric field would relate the global electric circuit while the radial component showed the electrical coupling between the lower atmosphere and the ionized Earth's environment. The variations of the values of field components for different heights as well as Maxwell's current have been evaluated. Coupling between the troposphere and the ionosphere is critically dependent on the height variations of electrical conductivity. Field-aligned electron density irregularities in the ionosphere may be investigated through the present analyses.
Model of Pulsed Electrical Discharge Machining (EDM using RL Circuit
Directory of Open Access Journals (Sweden)
Ade Erawan Bin Minhat
Full Text Available This article presents a model of pulsed Electrical Discharge Machining (EDM using RL circuit. There are several mathematical models have been successfully developed based on the initial, ignition and discharge phase of current and voltage gap. According to these models, the circuit schematic of transistor pulse power generator has been designed using electrical model in Matlab Simulink software to identify the profile of voltage and current during machining process. Then, the simulation results are compared with the experimental results.
Middle atmosphere electrical energy coupling
Hale, L. C.
The middle atmosphere (MA) has long been known as an absorber of radio waves, and as a region of nonlinear interactions among waves. The region of highest transverse conductivity near the top of the MA provides a common return for global thunderstorm, auroral Birkeland, and ionospheric dynamo currents, with possibilities for coupling among them. Their associated fields and other transverse fields map to lower altitudes depending on scale size. Evidence now exists for motion-driven aerosol generators, and for charge trapped at the base of magnetic field lines, both capable of producing large MA electric fields. Ionospheric Maxwell currents (curl H) parallel to the magnetic field appear to map to lower altitudes, with rapidly time-varying components appearing as displacement currents in the stratosphere. Lightning couples a (primarily ELF and ULF) current transient to the ionosphere and magnetosphere whose wave shape is largely dependent on the MA conductivity profile. Electrical energy is of direct significance mainly in the upper MA, but electrodynamic transport of minor constituents such as smoke particles or CN may be important at other altitudes.
30 CFR 75.518-1 - Electric equipment and circuits; overload and short circuit protection; minimum requirements.
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Electric equipment and circuits; overload and short circuit protection; minimum requirements. 75.518-1 Section 75.518-1 Mineral Resources MINE SAFETY...-UNDERGROUND COAL MINES Electrical Equipment-General § 75.518-1 Electric equipment and circuits; overload...
Bond-graph Methods for Electric Circuits Analysis
Directory of Open Access Journals (Sweden)
GRAVA Adriana
Full Text Available The paper presents a bond-graph method for solving and analyzing an electric circuit with four or more circuit loops. Using this method, the time for circuit analysis is much shorter then using a classicalmethod. Besides determining the intensities of electrical currents through the sides of the circuit, the bond-graphs provide the possibility to obtain the transmittance of the analyzed system applying a fast working method. The main advantage of bond-graphs is the interaction with various areas of physics. The analyzedelectrical circuit could be a part of a complex physical system that could be modeled and analyzed as a unitary system by using bond-graphs.
Using Hydraulic Network Models to Teach Electric Circuit Principles
Jones, Irvin; EERC (Engineering Education Research Center) Collaboration
Unlike other engineering disciplines, teaching electric circuit principles is difficult for some students because there isn't a visual context to rely on. So concepts such as electric potential, current, resistance, capacitance, and inductance have little meaning outside of their definition and the derived mathematical relationships. As a work in progress, we are developing a tool to support teaching, learning, and research of electric circuits. The tool will allow the user to design, build, and operate electric circuits in the form of hydraulic networks. We believe that this system will promote greater learning of electric circuit principles by visually realizing the conceptual and abstract concepts of electric circuits. Furthermore, as a teaching and learning tool, the hydraulic network system can be used to teach and improve comprehension of electrical principles in K through 12 classrooms and in cross-disciplinary environments such as Bioengineering, Mechanical Engineering, Industrial Engineering, and Aeronautical Engineering. As a research tool, the hydraulic network can model and simulate micro/nano bio-electro-chemical systems. Organization within the Swanson School of Engineering at the University of Pittsburgh.
An Unsolved Electric Circuit: A Common Misconception
Harsha, N. R. Sree; Sreedevi, A.; Prakash, Anupama
Despite a number of theories in circuit analysis, little is known about the behaviour of ideal equal voltage sources in parallel, connected across a resistive load. We neither have any theory that can predict the voltage source that provides the load current, nor is there any method to test it experimentally. In a series of experiments performed…
Stochastic Resonance Induced by Dichotomous Resistor in an Electric Circuit
Institute of Scientific and Technical Information of China (English)
LI Jing-Hui; HAN Yin-Xia
An electric circuit with dichotomous resistor is investigated.It is shown that the amplitude of the average electric current washing the resistor represents the phenomenon of stochastic resonance,which is the response as a function of the correlation time of the dichotomous resistor.
Introduction to Biosensors From Electric Circuits to Immunosensors
Yoon, Jeong-Yeol
Introduction to Biosensors: From Electric Circuits to Immunosensors discusses underlying circuitry of sensors for biomedical and biological engineers as well as biomedical sensing modalities for electrical engineers while providing an applications-based approach to the study of biosensors with over 13 extensive, hands-on labs. The material is presented using a building-block approach, beginning with the fundamentals of sensor design and temperature sensors and ending with more complicated biosensors. This book also: Provides electrical engineers with the specific knowledge they need to understand biological sensing modalities Provides biomedical engineers with a solid background in circuits and systems Includes complete coverage of temperature sensors, electrochemical sensors, DNA and immunosensors, piezoelectric sensors and immunosensing in a micofluidic device Introduction to Biosensors: From Electric Circuits to Immunosensors aims to provide an interdisciplinary approach to biosensors that will be apprecia...
Updating the science of atmospheric electricity
Pinto, Osmar, Jr.; Williams, Earle R.
XIV International Conference on Atmospheric Electricity; Rio de Janeiro, Brazil, 7-12 August 2011 The main goal of the XIV International Conference on Atmospheric Electricity (ICAE 2011) was to provide a comprehensive description of the status of knowledge in the field of atmospheric electricity, as well as to provide an opportunity for extensive interaction among researchers in this field. The history of the ICAE goes back to the first conference held in May 1954 in Portsmouth, N. H. The conference was attended by 51 scientists from 10 countries, and only three topics were addressed: fair weather electricity, thunderstorm electrification, and lightning.
Switchless charge-discharge circuit for electrical capacitance tomography
International Nuclear Information System (INIS)
The main factor limiting the performance of electrical capacitance tomography (ECT) is an extremely low value of inter-electrode capacitances. The charge-discharge circuit is a well suited circuit for a small capacitance measurement due to its immunity to noise and stray capacitance, although it has a problem associated with a charge injected by the analogue switches, which results in a dc offset. This paper presents a new diode-based circuit for capacitance measurement in which a charge transfer method is realized without switches. The circuit was built and tested in one channel configuration with 16 multiplexed electrodes. The performance of the elaborated circuit and a comparison with a classic charge-discharge circuit are presented. The elaborated circuit can be used for sensors with inter-electrode capacitances not lower than 10 fF. The presented approach allows us to obtain a similar performance to the classic charge-discharge circuit, but has a simplified design. A lack of the need to synchronize the analogue switches in the transmitter and the receiver part of this circuit could be a desirable feature in the design of measurement systems integrated with electrodes. (paper)
High-speed Integrated Circuits for electrical/Optical Interfaces
DEFF Research Database (Denmark)
Jespersen, Christoffer Felix
This thesis is a continuation of the effort to increase the bandwidth of communicationnetworks. The thesis presents the results of the design of several high-speed electrical ircuits for an electrical/optical interface. These circuits have been a contribution to the ESTA project in collaboration...... circuits at the receiver interface, though VCOs are also found in the transmitter where a multitude of independent sources have to be mutually synchronized before multiplexing. The circuits are based on an InP DHBT process (VIP-2) supplied by Vitesse and made publicly available as MPW. The VIP-2 process...... represents the avant-garde of InP technology, with ft and fmax well above 300 GHz. Principles of high speed design are presented and described as a useful background before proceeding to circuits. A static divider is used as an example to illustrate many of the design principles. Theory and fundamentals...
Atmospheric electricity and aerosol-cloud interactions in earth's atmosphere
Manninen, Hanna E.; Tammet, Hannes; Mäkelä, Antti; Haapalainen, Jussi; Mirme, Sander; Nieminen, Tuomo; Franchin, Alessandro; Petäjä, Tuukka; Kulmala, Markku; Hõrrak, Urmas
Firstly, atmospheric ions play an important role in the fair weather electricity in Earth's atmosphere. Small ions, or charged molecular clusters, carry electric currents in the atmosphere. These small ions are continuously present, and their lifetime in lower atmosphere is about one minute. It's essential to find out a connection between the production rate of cluster ions, ion-ion recombination, and ion-aerosol attachment, and their ambient concentrations, in order to understand electrical properties of air. Secondly, atmospheric ions are important for Earth's climate, due to their potential role in secondary aerosol formation, which can lead to increased number of cloud condensation nuclei (CCN), which in turn can change the cloud properties. Our aim is to quantify the connections between these two important roles of air ions based on field observations.
Students' Understanding of Direct Current Resistive Electrical Circuits
Engelhardt, P V; Engelhardt, Paula V.; Beichner, Robert J.
Research has shown that both high school and university students' reasoning patterns regarding direct current resistive electric circuits often differ from the currently accepted explanations. At present, there are no standard diagnostic examinations in electric circuits. Two versions of a diagnostic instrument called Determining and Interpreting Resistive Electric circuits Concepts Tests (DIRECT) were developed, each consisting of 29 questions. The information provided by the exam provides classroom instructors a means with which to evaluate the progress and conceptual difficulties of their students and their instructional methods. It can be used to evaluate curricular packages and/or other supplemental materials for their effectiveness in overcoming students' conceptual difficulties. The analyses indicate that students, especially females, tend to hold multiple misconceptions, even after instruction. During interviews, the idea that the battery is a constant source of current was used most often in answerin...
30 CFR 77.501 - Electric distribution circuits and equipment; repair.
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Electric distribution circuits and equipment... OF UNDERGROUND COAL MINES Electrical Equipment-General § 77.501 Electric distribution circuits and equipment; repair. No electrical work shall be performed on electric distribution circuits or...
In situ measurements of contributions to the global electrical circuit by a thunderstorm in southeastern Brazil
Thomas, J.N.; Holzworth, R.H.; McCarthy, M.P.
The global electrical circuit, which maintains a potential of about 280??kV between the earth and the ionosphere, is thought to be driven mainly by thunderstorms and lightning. However, very few in situ measurements of electrical current above thunderstorms have been successfully obtained. In this paper, we present dc to very low frequency electric fields and atmospheric conductivity measured in the stratosphere (30-35??km altitude) above an active thunderstorm in southeastern Brazil. From these measurements, we estimate the mean quasi-static conduction current during the storm period to be 2.5 ?? 1.25??A. Additionally, we examine the transient conduction currents following a large positive cloud-to-ground (+ CG) lightning flash and typical - CG flashes. We find that the majority of the total current is attributed to the quasi-static thundercloud charge, rather than lightning, which supports the classical Wilson model for the global electrical circuit.
Electrical overstress (EOS) devices, circuits and systems
Voldman, Steven H
Electrical Overstress (EOS) continues to impact semiconductor manufacturing, semiconductor components and systems as technologies scale from micro- to nano-electronics. This bookteaches the fundamentals of electrical overstress and how to minimize and mitigate EOS failures. The text provides a clear picture of EOS phenomena, EOS origins, EOS sources, EOS physics, EOS failure mechanisms, and EOS on-chip and system design. It provides an illuminating insight into the sources of EOS in manufacturing, integration of on-chip, and system level EOS protection networks, followed by examples in spe
Electric fields in the middle atmosphere
Holzworth, Robert H.
Middle atmospheric electrodynamics is characterized by discussing the present understanding of the background electrical conductivity and the sources for electric fields and currents within the medium. Results of recent research that contradicts the historical view of the region are presented. Of principal interest to the present direction of the field is the attempt to quantize the low and high altitude electric generators such as thunderstorms or ionospheric convection. It is noted that the many-fold increase in available electric parameter data from within the middle atmosphere has been a great stimulus to recent research; however, these measurements have tended to raise more questions than they give answers.
Quantum interface between an electrical circuit and a single atom
Kielpinski, D; Woolley, M J; Milburn, G J; Taylor, J M
We show how to bridge the divide between atomic systems and electronic devices by engineering a coupling between the motion of a single ion and the quantized electric field of a resonant circuit. Our method can be used to couple the internal state of an ion to the quantized circuit with the same speed as the internal-state coupling between two ions. All the well-known quantum information protocols linking ion internal and motional states can be converted to protocols between circuit photons and ion internal states. Our results enable quantum interfaces between solid state qubits, atomic qubits, and light, and lay the groundwork for a direct quantum connection between electrical and atomic metrology standards.
Turkish Students' Conceptions about the Simple Electric Circuits
Cepni, Salih; Keles, Esra
In this study, the Turkish students' understanding level of electric circuits consisting of two bulbs and one battery was investigated by using open-ended questions. Two-hundred fifty students, whose ages range from 11 to 22, were chosen from five different groups at primary, secondary and university levels in Trabzon in Turkey. In analyzing…
Web-Based Trainer for Electrical Circuit Analysis
Weyten, L.; Rombouts, P.; De Maeyer, J.
A Web-based system for training electric circuit analysis is presented in this paper. It is centered on symbolic analysis techniques and it not only verifies the student's final answer, but it also tracks and coaches him/her through all steps of his/her reasoning path. The system mimics homework assignments, enhanced by immediate personalized…
Simulating Harmonic Oscillator and Electrical Circuits: A Didactical Proposal
Albano, Giovannina; D'Apice, Ciro; Tomasiello, Stefania
A Mathematica[TM] package is described that uses simulations and animations to illustrate key concepts in harmonic oscillation and electric circuits for students not majoring in physics or mathematics. Students are not required to know the Mathematica[TM] environment: a user-friendly interface with buttons functionalities and on-line help allows…
Teaching an Electrical Circuits Course Using a Virtual Lab
Rahman, Md Zahidur
This paper describes designing and implementing a scholarship of teaching and learning (SoTL) study in a basic electrical circuits course at LaGuardia Community College. Inspired by my understanding of Shulman's (2005) concept of "signature pedagogy" and Mazur's (2009) emphasis on student-centered approaches, and aware that our…
Peculiarities of dynamics of the global electric circuit elements during very low solar activity
International Nuclear Information System (INIS)
Complete text of publication follows. Accumulated data about dynamics of various elements of the solar - terrestrial relationship allow us to approach the problem of the solar activity influence on the middle atmosphere with taking into account role of the ground surface electrical conductivity. A special importance of this problem appears in the 23 cycle of the solar activity (2006-2009 years). This period is characterized by unusually low values of solar UV radiation as well as of magnitudes of the solar wind magnetic field. It means that impact of the solar electromagnetic energy on the near - Earth space is much weaker than usually. The Earth global electric circuit which includes the ionosphere, the stratosphere and the ground surface as its vital components has its own specific features during considered period. In this paper we outline these peculiarities of the global electric circuit and its influence on the middle atmosphere. First of all, we will demonstrate that experimental values of the atmospheric electric field (observations at Vostok Station, Antarctica) are the lowest during the last 3 years. We claim that role of the electric conductivity of the ground surface begin to play more significant role in the dynamics of the global electric circuit. To confirm that suggestion we studied interaction between the stratospheric temperature distribution in the high latitudes in winters of 2008 - 2009 and the area of the old sea ice (pack ice) in the Arctic Ocean during the same period. We will show that the areas of the low temperatures in the polar stratosphere correspond pretty well to distribution of the pack ice in the Arctic. Our explanation of the phenomena is based on difference of electric conductivity of the ice and of the open ocean water.
Modelling a river catchment using an electrical circuit analogue
Directory of Open Access Journals (Sweden)
C. G. Collier
Full Text Available An electrical circuit analogue of a river catchment is described from which is derived an hydrological model of river flow called the River Electrical Water Analogue Research and Development (REWARD model. The model is based upon an analytic solution to the equation governing the flow of electricity in an inductance-capacitance-resistance (LCR circuit. An interpretation of L, C and R in terms of catchment parameters and physical processes is proposed, and tested for the River Irwell catchment in northwest England. Hydrograph characteristics evaluated using the model are compared with observed hydrographs, confirming that the modelling approach does provide a reliable framework within which to investigate the impact of variations in model input data.
The Role of Anomalous Data in Restructuring Fourth Graders' Frameworks for Understanding Electric Circuits.
Shepardson, Daniel P.; Moje, Elizabeth B.
Focuses on students' understanding of electric circuits. Findings suggest that children's interpretive frameworks of electric circuits are reflected in the specificity of the details, consistency, and coherence of their understanding. Contains 23 references. (DDR)
D. V. Ustymenko
The microprocessor device of protection of electric chains of electric motors from short circuit currents, in which switching-off of a short circuit current is carried out before it achieves a shock value, is presented.
Using graph theory for automated electric circuit solving
Toscano, L.; Stella, S.; Milotti, E.
Graph theory plays many important roles in modern physics and in many different contexts, spanning diverse topics such as the description of scale-free networks and the structure of the universe as a complex directed graph in causal set theory. Graph theory is also ideally suited to describe many concepts in computer science. Therefore it is increasingly important for physics students to master the basic concepts of graph theory. Here we describe a student project where we develop a computational approach to electric circuit solving which is based on graph theoretic concepts. This highly multidisciplinary approach combines abstract mathematics, linear algebra, the physics of circuits, and computer programming to reach the ambitious goal of implementing automated circuit solving.
Mathematical Modelling and Simulation of Electrical Circuits and Semiconductor Devices
Merten, K; Bulirsch, R
Numerical simulation and modelling of electric circuits and semiconductor devices are of primal interest in today's high technology industries. At the Oberwolfach Conference more than forty scientists from around the world, in cluding applied mathematicians and electrical engineers from industry and universities, presented new results in this area of growing importance. The contributions to this conference are presented in these proceedings. They include contributions on special topics of current interest in circuit and device simulation, as well as contributions that present an overview of the field. In the semiconductor area special lectures were given on mixed finite element methods and iterative procedures for the solution of large linear systems. For three dimensional models new discretization procedures including software packages were presented. Con nections between semiconductor equations and the Boltzmann equation were shown as well as relations to the quantum transport equation. Other issues dis...
Electrical properties of ions in the atmosphere of Titan
Energy Technology Data Exchange (ETDEWEB)
Owen, N R; Aplin, K L; Stevens, P A [Space Science and Technology Department, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, 0X11 OQX (United Kingdom)], E-mail: email@example.com
The Permittivity, Wave and Altimetry (PWA) package on the Huygens probe measured atmospheric electrical activity during its 14 January 2005 descent into Titan's atmosphere. Electrical mobilities of positive ions have been estimated using a combination of predictions of mass from the available chemical models, and the atmospheric properties measured by Huygens. Disc-shaped relaxation probes were used on the PWA to measure air conductivity. In this paper we present the extension of an inversion technique, originally developed to extract ion mobility information from cylindrical relaxation probe data, to the disc geometry. The maximum distance from which typical positive ion species are influenced by the electric field of the relaxation probe in Titan's troposphere and stratosphere is calculated, and found to be {approx}10{mu}m. However, loss of positive ion data from the Huygens probe prevents the application of the new technique. Based on the Huygens data, evidence for, and possible characteristics of, a global electric circuit on Titan are also discussed.
49 CFR 236.16 - Electric lock, main track releasing circuit.
... 49 Transportation 4 2010-10-01 2010-10-01 false Electric lock, main track releasing circuit. 236... Rules and Instructions: All Systems General § 236.16 Electric lock, main track releasing circuit. When an electric lock releasing circuit is provided on the main track to permit a train or an engine...
Nonlinear lumped circuit modeling of an atmospheric pressure rf discharge
Lapke, M.; Ziegler, D.; Mussenbrock, T.; Gans, T.; Schulz-von der Gathen, V.
The subject of our modeling approach is a specifically modified version of the atmospheric pressure plasma jet (APPJ, originally proposed by Selwyn and coworkers^1) with reduced discharge volume, the micro atmospheric pressure plasma jet (μ-APPJ). The μ-APPJ is a homogeneous nonequilibrium discharge operated with Argon or Helium as the feedstock gas and a percentage volume admixture of a molecular gas (O2, H2, N2). The efficiency of the discharge is mainly due to the dissociated and activated molecules in the effluent that can be selected depending on the application. A variety of applications in surface treatment have already been demonstrated, e.g., in semiconductor technology, restoration and bio-medicine. In this contribution we present and analyze a nonlinear lumped circuit model of the μ-APPJ. We apply a two-scale formalism. The bulk is modeled by a generalized Ohm's law, whereas the sheath is described on a considerably higher level of mathematical sophistication. The main focus lies on the spectrum of the discharge current in order to support the characterization of the discharge via model-based diagnostics, i.e., the estimation of the spatially averaged electron density from the frequency of certain self-excitated collective resonance modes. J. Park et al., Appl. Phy. Lett. 76, 288 (2000)
Competitive Learning in Electric Circuit Theory Using MOODLE
Barroso, Ramón J. Durán; Bahillo, Alfonso; Fernández, Patricia; Merayo, Noemí; de Miguel, Ignacio; Aguado, Juan Carlos; Lorenzo, Rubén M.; Domi, Evaristo J. Abril
We have recently introduced an activity based on competitive learning in the subject of "Electric Circuit Theory", which is taught in the first year of the 3-year degree of Technical Telecommunication Engineering at the University of Valladolid. Students are divided into groups and compete in a tournament through a series of knockout rounds. In each of these rounds, a contending group solves an electric circuit problem, and proposes an update on it, which must then be solved by the other contending team, and so on until one of them fails. In order to facilitate the management of the game, the open-source MOODLE platform has been employed. This paper describes the experience and the learning benefits that it brings, as well as how the method has been implemented using the MOODLE platform. Moreover, the satisfaction of the students and the time required by the students and by the teacher when using this technique are also analyzed. While the experience focuses on the subject of "Electric Circuit Theory", it is worthy to note that it may be easily extended to other subjects.
Reduce of Threshold of Laser Inducing Breakdown in Atmosphere by Introducing an Electric Spark
Institute of Scientific and Technical Information of China (English)
ZHANG Xian-Bin; SHI Wei; LI Hua
@@ We report laser-generated plasmas in atmosphere with electrical spark generated by a synchronization circuit.The breakdown thresholds under the conditions that the electrical spark is used and not used are compared.The breakdown threshold has a distinct decrease after the electrical spark is used. Breakdown thresholds as afunction of atmosphere pressure have also been measured at laser wavelengths 532nm and 1064 nm for the laserpulse width of 15ns. We also discuss the principle and performances of the ionized atmosphere by Nd:YAGlaser under the condition of electrical spark introduction. Multiphoton ionization and cascade ionization playimportant roles in the whole process of atmosphere ionization. The free electron induced by electrical spark cansupply the initialization free electron number for multiphoton ionization and cascade ionization. A model forbreakdown in atmosphere, which is in good agreement with the experimental results, is described.
Java Based Symbolic Circuit Solver For Electrical Engineering Curriculum
Directory of Open Access Journals (Sweden)
Ruba Akram Amarin
Full Text Available The interactive technical electronic book, TechEBook, currently under development at the University of Central Florida (UCF, introduces a paradigm shift by replacing the traditional electrical engineering course with topic-driven modules that provide a useful tool for engineers and scientists. The TechEBook comprises the two worlds of classical circuit books and interactive operating platforms such as iPads, laptops and desktops. The TechEBook provides an interactive applets screen that holds many modules, each of which has a specific application in the self learning process. This paper describes one of the interactive techniques in the TechEBook known as Symbolic Circuit Solver (SymCirc. The SymCirc develops a versatile symbolic based linear circuit with a switches solver. The solver works by accepting a Netlist and the element that the user wants to find the voltage across or current on, as input parameters. Then it either produces the plot or the time domain expression of the output. Frequency domain plots or Symbolic Transfer Functions are also produced. The solver gets its input from a Web-based GUI circuit drawer developed at UCF. Typical simulation tools that electrical engineers encounter are numerical in nature, that is, when presented with an input circuit they iteratively solve the circuit across a set of small time steps. The result is represented as a data set of output versus time, which can be plotted for further inspection. Such results do not help users understand the ultimate nature of circuits as Linear Time Invariant systems with a finite dimensional basis in the solution space. SymCirc provides all simulation results as time domain expressions composed of the basic functions that exclusively include exponentials, sines, cosines and/or t raised to any power. This paper explains the motivation behind SymCirc, the Graphical User Interface front end and how the solver actually works. The paper also presents some examples and
Dynamical properties of electrical circuits with fully nonlinear memristors
Riaza, Ricardo
The recent design of a nanoscale device with a memristive characteristic has had a great impact in nonlinear circuit theory. Such a device, whose existence was predicted by Leon Chua in 1971, is governed by a charge-dependent voltage-current relation of the form $v=M(q)i$. In this paper we show that allowing for a fully nonlinear characteristic $v=\\eta(q, i)$ in memristive devices provides a general framework for modeling and analyzing a very broad family of electrical and electronic circuits; Chua's memristors are particular instances in which $\\eta(q,i)$ is linear in $i$. We examine several dynamical features of circuits with fully nonlinear memristors, accommodating not only charge-controlled but also flux-controlled ones, with a characteristic of the form $i=\\zeta(\\varphi, v)$. Our results apply in particular to Chua's memristive circuits; certain properties of these can be seen as a consequence of the special form of the elastance and reluctance matrices displayed by Chua's memristors.
5th International Conference on Atmospheric Electricity
Reiter, Reinhold; Landsberg, Helmut
These Proceedings are published to give a full account of the Fifth International Conference on Atmospheric Electricity held in September 1974 in Garmisch-Partenkirchen in the Bavarian Alps in Germany. Traditionally, the Proceedings of these Conferences have served as reference books updating the textbooks and monographs on Atmospheric Electricity. As treated by these Conferences, Atmos pheric Electricity covers all aspects of this science, including the processes and problems which reach out into the Earth's environment as well as analogous processes on other planets and on the Moon. A history of these Conferences, an account of their purpose, and an outline of the scope and the preparation is to be found at the end of these Proceedings. There, also the Business Meetings of the involved organizations are mentioned. The Proceedings closely follow the original program and are accordingly organized into "Sessions". The papers printed in each "Session" in this book are the ones which were accepted for the sess...
Pupils' understanding of simple electrical circuits. Some implications for instruction
Shipstone, David
There have been many studies worldwide of children's understanding of basic electrical concepts so that there is now quite a clear picture of many of their difficulties. By contrast, work on remediation is in its infancy. The article describes research findings concerning children's difficulties with the concepts of circuit, current and electrical energy and discusses some possible approaches to instruction which arise in the light of these findings. Much of the research carried out has been within the paradigm of constructivist psychology which views all human beings as prototypical scientists, constructing hypotheses and testing these against experience as their way of understanding the world around them. In seeking to understand electrical phenomena children construct a variety of explanatory conceptual models, some of which they then hold very tenaciously.
30 CFR 18.51 - Electrical protection of circuits and equipment.
... TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES... circuit-interrupting device(s) shall be used to protect each ungrounded conductor of a branch circuit at the junction with the main circuit when the branch-circuit conductor(s) has a current...
Basic electric circuit theory a one-semester text
Mayergoyz, Isaak D
This is the only book on the market that has been conceived and deliberately written as a one-semester text on basic electric circuit theory. As such, this book employs a novel approach to the exposition of the material in which phasors and ac steady-state analysis are introduced at the beginning. This allows one to use phasors in the discussion of transients excited by ac sources, which makes the presentation of transients more comprehensive and meaningful. Furthermore, the machinery of phasors paves the road to the introduction of transfer functions, which are then used in the analysis of tr
Adaptive Electronic Quizzing Method for Introductory Electrical Circuit Course
Directory of Open Access Journals (Sweden)
Issa Batarseh
Full Text Available The interactive technical electronic book, TechEBook, currently under development at the University of Central Florida, provides a useful tool for engineers and scientists through unique features compared to the most used traditional electrical circuit textbooks available in the market. TechEBook has comprised the two worlds of classical circuit books and an interactive operating platform such as laptops and desktops utilizing Java Virtual Machine operator. The TechEBook provides an interactive applets screen that holds many modules, in which each had a specific application in the self learning process. This paper describes one of the interactive techniques in the TechEBook known as, QuizMe, for evaluating the readers' performance and the overall understanding for all subjects at any stage. The QuizMe will be displayed after each section in the TechEBook for the user to evaluate his/her understanding, which introduces the term me-learning, as a comprehensive full experience for self or individualized education. In this paper, a practical example of applying the QuizMe feature is discussed as part of a basic electrical engineering course currently given at the University of Central Florida.
Inferring convective responses to El Niño with atmospheric electricity measurements at Shetland
International Nuclear Information System (INIS)
Pacific ocean temperature anomalies associated with the El Niño–Southern Oscillation (ENSO) modulate atmospheric convection and hence thunderstorm electrification. The generated current flows globally via the atmospheric electric circuit, which can be monitored anywhere on Earth. Atmospheric electricity measurements made at Shetland (in Scotland) display a mean global circuit response to ENSO that is characterized by strengthening during 'El Niño' conditions, and weakening during 'La Niña' conditions. Examining the hourly varying response indicates that a potential gradient (PG) increase around noon UT is likely to be associated with a change in atmospheric convection and resultant lightning activity over equatorial Africa and Eastern Asia. A secondary increase in PG just after midnight UT can be attributed to more shower clouds in the central Pacific ocean during an 'El Niño'.
The impact of space electric field research on atmospheric studies
Mozer, F. S.
Space measurements of electric fields have provided instrumentation for measuring atmospheric parameters and a better basis for understanding the electrical coupling between the magnetosphere and the atmosphere. Applications of an incoherent scatter radar (developed for ionospheric electric field research) to the measurement of atmospheric winds and turbulence and of Langmuir double probes (also developed for space research) for measurement of atmospheric electric fields are described. The increased knowledge of magnetospheric electric fields has focused attention on the electrical coupling between the magnetosphere and the atmosphere with conclusions that should considerably modify previous physical concepts in both domains.
An investigation of algebraic quantum dynamics for mesoscopic coupled electric circuits with mutual inductance
Pahlavani, H.; Kolur, E. Rahmanpour
Based on the electrical charge discreteness, the Hamiltonian operator for the mutual inductance coupled quantum mesoscopic LC circuits has been found. The persistent current on two driven coupled mesoscopic electric pure L circuits (two quantum loops) has been obtained by using algebraic quantum dynamic approach. The influence of the mutual inductance on energy spectrum and quantum fluctuations of the charge and current for two coupled quantum electric mesoscopic LC circuits have been investigated.
Measuring User Similarity Using Electric Circuit Analysis: Application to Collaborative Filtering
Joonhyuk Yang; Jinwook Kim; Wonjoon Kim; Young Hwan Kim
We propose a new technique of measuring user similarity in collaborative filtering using electric circuit analysis. Electric circuit analysis is used to measure the potential differences between nodes on an electric circuit. In this paper, by applying this method to transaction networks comprising users and items, i.e., user-item matrix, and by using the full information about the relationship structure of users in the perspective of item adoption, we overcome the limitations of one-to-one si...
Simple circuit to improve electric field homogeneity in contour-clamped homogeneous electric field chambers.
Herrera, José A; Canino, Carlos A; López-Cánovas, Lilia; Gigato, Regnar; Riverón, Ana Maria
We redesigned contour-clamped homogeneous electric field (CHEF) circuitry to eliminate crossover distortion, to set identical potentials at electrodes of each equipotential pair and to drive pairs with transistors in emitter follower stages. An equipotential pair comprised the two electrodes set at the same potential to provide electric field homogeneity inside of the hexagonal array. The new circuitry consisted of two identical circuits, each having a resistor ladder, diodes and transistors. Both circuits were interconnected by diodes that controlled the current flow to electrodes when the array was energized in the 'A' or 'B' direction of the electric field. The total number of transistors was two-thirds of the total number of electrodes. Average voltage deviation from potentials expected at electrodes to achieve a homogeneous electric field was 0.06 V, whereas 0.44 V was obtained with another circuit that used transistors in push-pull stages. The new voltage clamp unit is cheap, generated homogeneous electric field, and gave reproducible and undistorted DNA band patterns. PMID:12707904
New Breakdown Electric Field Calculation for SF6 High Voltage Circuit Breaker Applications
Institute of Scientific and Technical Information of China (English)
Ph.ROBIN-JOUAN; M.YOUSFI
The critical electric fields of hot SF6 are calculated including both electron and ion kinetics in wide ranges of temperature and pressure,namely from 300 K up to 4000 K and 2 atmospheres up to 32 atmospheres respectively.Based on solving a multi-term electron Boltzmann equation the calculations use improved electron-gas collision cross sections for twelve SF6 dissociation products with a particular emphasis on the electron-vibrating molecule interactions.The ion kinetics is also considered and its role on the critical field becomes non negligible as the temperature is above 2000 K.These critical fields are then used in hydrodynamics simulations which correctly predict the circuit breaker behaviours observed in the case of breaking tests.
Fourth Graders' Framing of an Electric Circuits Task
Winters, Victoria; Hammer, David
Previous work shows that college students have more difficulty lighting a bulb with a single wire and a battery than with two wires [1], results that have informed the design of activities [2]. We present some unexpected findings from two 4th grade classes engaged in a 15-hour inquiry module on electric circuits. Students successfully lit the bulb with a single wire in a variety of ways, but students from both classes showed and expressed the view that the bulb must be in direct contact with a battery in order for it to light. We suggest this arose from students framing the task as a building activity, and we analyze two classroom episodes in support of this interpretation.
On Parameterization of the Global Electric Circuit Generators
Slyunyaev, N. N.; Zhidkov, A. A.
We consider the problem of generator parameterization in the global electric circuit (GEC) models. The relationship between the charge density and external current density distributions inside a thundercloud is studied using a one-dimensional description and a three-dimensional GEC model. It is shown that drastic conductivity variations in the vicinity of the cloud boundaries have a significant impact on the structure of the charge distribution inside the cloud. Certain restrictions on the charge density distribution in a realistic thunderstorm are found. The possibility to allow for conductivity inhomogeneities in the thunderstorm regions by introducing an effective external current density is demonstrated. Replacement of realistic thunderstorms with equivalent current dipoles in the GEC models is substantiated, an equation for the equivalent current is obtained, and the applicability range of this equation is analyzed. Relationships between the main GEC characteristics under variable parameterization of GEC generators are discussed.
Analogue Electrical Circuit for Simulation of the Duffing-Holmes Equation
DEFF Research Database (Denmark)
Tamaseviciute, E.; Tamasevicius, A.; Mykolaitis, G.;
An extremely simple second order analogue electrical circuit for simulating the two-well Duffing-Holmes mathematical oscillator is described. Numerical results and analogue electrical simulations are illustrated with the snapshots of chaotic waveforms, phase portraits (Lissajous figures) and stro......An extremely simple second order analogue electrical circuit for simulating the two-well Duffing-Holmes mathematical oscillator is described. Numerical results and analogue electrical simulations are illustrated with the snapshots of chaotic waveforms, phase portraits (Lissajous figures...
Method of boundary testing of the electric circuits and its application for calculating electric tolerances. [electric equipment tests
Redkina, N. P.
Boundary testing of electric circuits includes preliminary and limiting tests. Preliminary tests permit determination of the critical parameters causing the greatest deviation of the output parameter of the system. The boundary tests offer the possibility of determining the limits of the fitness of the system with simultaneous variation of its critical parameters.
Factors Mediating the Effect of Gender on Ninth-Grade Turkish Students' Misconceptions Concerning Electric Circuits
Sencar, Selen; Eryilmaz, Ali
This study was designed to identify and analyze possible factors that mediate the effect of gender on ninth-grade Turkish students' misconceptions concerning electric circuits. A Simple Electric Circuit Concept Test (SECCT), including items with both practical and theoretical contexts, and an Interest-Experience Questionnaire about Electricity…
Pre-Service and In-Service Physics Teachers' Ideas about Simple Electric Circuits
Kucukozer, Huseyin; Demirci, Neset
The aim of the study is to determine pre-service and high school physics teachers' ideas about simple electric circuits. In this study, a test containing eight questions related to simple electric circuits was given to the pre-service physics teachers (32 subjects) that had graduated from Balikesir University, Necatibey Faculty of Education, the…
The Electron Runaround: Understanding Electric Circuit Basics through a Classroom Activity
Singh, Vandana
Several misconceptions abound among college students taking their first general physics course, and to some extent pre-engineering physics students, regarding the physics and applications of electric circuits. Analogies used in textbooks, such as those that liken an electric circuit to a piped closed loop of water driven by a water pump, do not…
Investigation of Status of Primary School Teaching Students as Regards Installing and Figuring Out Electrical Circuits
ÇELİK, Harun; PEKTAŞ, Hüseyin Miraç; Murat DEMİRBAŞ
This study is carried out to present students' problems which are about electric circuit experiments and are faced during the experiments process in Science and Technology Laboratory Course. The problems are associated with setting up simple electric circuits, fi guring out and using circuit elements (resistances in series, parallel and mixed connection). Researchers used special case method because the method provides utilizing both qualitative and quantitative methods in this study. Firstly...
Applications of Electrified Dust and Dust Devil Electrodynamics to Martian Atmospheric Electricity
Harrison, R. G.; Barth, E.; Esposito, F.; Merrison, J.; Montmessin, F.; Aplin, K. L.; Borlina, C.; Berthelier, J. J.; Déprez, G.; Farrell, W. M.; Houghton, I. M. P.; Renno, N. O.; Nicoll, K. A.; Tripathi, S. N.; Zimmerman, M.
Atmospheric transport and suspension of dust frequently brings electrification, which may be substantial. Electric fields of 10 kV m-1 to 100 kV m-1 have been observed at the surface beneath suspended dust in the terrestrial atmosphere, and some electrification has been observed to persist in dust at levels to 5 km, as well as in volcanic plumes. The interaction between individual particles which causes the electrification is incompletely understood, and multiple processes are thought to be acting. A variation in particle charge with particle size, and the effect of gravitational separation explains to, some extent, the charge structures observed in terrestrial dust storms. More extensive flow-based modelling demonstrates that bulk electric fields in excess of 10 kV m-1 can be obtained rapidly (in less than 10 s) from rotating dust systems (dust devils) and that terrestrial breakdown fields can be obtained. Modelled profiles of electrical conductivity in the Martian atmosphere suggest the possibility of dust electrification, and dust devils have been suggested as a mechanism of charge separation able to maintain current flow between one region of the atmosphere and another, through a global circuit. Fundamental new understanding of Martian atmospheric electricity will result from the ExoMars mission, which carries the DREAMS (Dust characterization, Risk Assessment, and Environment Analyser on the Martian Surface)—MicroARES (Atmospheric Radiation and Electricity Sensor) instrumentation to Mars in 2016 for the first in situ electrical measurements.
Carnegie Institution Atmospheric-Electricity and Meteorological Data
National Oceanic and Atmospheric Administration, Department of Commerce — The Department of Terrestrial Magnetism at the Carnegie Institute of Science conducted observations of atmospheric electricity and magnetic storms. In addition to...
Displacement damage analysis and modified electrical equivalent circuit for electron and photon-irradiated silicon solar cells
Arjhangmehr, Afshin; Feghhi, Seyed Amir Hossein
Solar modules and arrays are the conventional energy resources of space satellites. Outside the earth's atmosphere, solar panels experience abnormal radiation environments and because of incident particles, photovoltaic (PV) parameters degrade. This article tries to analyze the electrical performance of electron and photon-irradiated mono-crystalline silicon (mono-Si) solar cells. PV cells are irradiated by mono-energetic electrons and poly-energetic photons and immediately characterized after the irradiation. The mean degradation of the maximum power (Pmax) of silicon solar cells is presented and correlated using the displacement damage dose (Dd) methodology. This method simplifies evaluation of cell performance in space radiation environments and produces a single characteristic curve for Pmax degradation. Furthermore, complete analysis of the results revealed that the open-circuit voltage (Voc) and the filling factor of mono-Si cells did not significantly change during the irradiation and were independent of the radiation type and fluence. Moreover, a new technique is developed that adapts the irradiation-induced effects in a single-cell equivalent electrical circuit and adjusts its elements. The "modified circuit" is capable of modeling the "radiation damage" in the electrical behavior of mono-Si solar cells and simplifies the designing of the compensation circuits.
Unit: Electric Circuits, Inspection Pack, National Trial Print.
Australian Science Education Project, Toorak, Victoria.
As a part of the unit materials in the series produced by the Australian Science Education Project, this teacher edition is primarily composed of a core relating to simple circuits, a test form, and options. Options are given under the headings: Your Invention; "How Long Does a Call Last?"; One, Two, Three Wires; Parallel Circuits; More Cells; The…
Analysis of a Piezo Electric Driver Circuit for Use in a Fabry-Perot Interferometer
Directory of Open Access Journals (Sweden)
Maithya J. Mutuku
Full Text Available The design and fabrication of piezo electric driver circuit is presented and analysed. The output voltage which is a triangular wave voltage and frequency of the driver circuit were measured and set at 80 V peak to peak and an output frequency of 1 KHz. A photo detector circuit which receives the output beam from the confocal Fabry- perot interferometer (CFPI through the photodiode is as well presented
Design Failures in Aerospace Electrical Systems(The Identification of Sneak Circuits
Directory of Open Access Journals (Sweden)
C. Goodchild
Full Text Available The malfunction or failure of an aircraft electrical system because signal or power flow paths were unintentionally designed into the electrical circuit, is known to be the cause of several major failures of engineering systems. These unintentional signal or power paths are called sneak circuits. The nature of Sneak Circuits was first considered after they had been identified as the cause of some spectacular and expensive rocket failures in the United States space programme. This paper reviews the status of Sneak Circuit Analysis (SCA and presents a general systematic approach the author has devised to identify sneak circuits during the circuits design phase. The application of the method of SCA is illustrated with a case study. The paper makes a case to take the investigation of an electrical failure or malfunction beyond the identification of a failed component to include a search for possible sneak circuits. The obvious fact that could result from the discovery of a sneak circuit is the shift in legal responsibility from the component manufacturer to the circuit designer.
Technological Literacy Learning with Cumulative and Stepwise Integration of Equations into Electrical Circuit Diagrams
Ozogul, G.; Johnson, A. M.; Moreno, R.; Reisslein, M.
Technological literacy education involves the teaching of basic engineering principles and problem solving, including elementary electrical circuit analysis, to non-engineering students. Learning materials on circuit analysis typically rely on equations and schematic diagrams, which are often unfamiliar to non-engineering students. The goal of…
Directory of Open Access Journals (Sweden)
L. V. Dubinets
Full Text Available In the article the issue of influence of vortical currents on rate of change of short circuit current is considered, a mathematical model for the calculation of short circuit currents in the traction mode in the power circuits of DC electric rolling stock is presented, and the research results are given.
Institute of Scientific and Technical Information of China (English)
By using the charge and current in a quantization resistance-inductance-capacitance (RLC) electric circuit, we construct a pair of canonical variables. Using this pair of variables and the thermal field dynamics, we obtain the fluctuations of charge and current in the RLC electric circuit at finite temperatures. It is shown that the fluctuations increase with increasing temperature and decrease with prolonging of time.
Frequency response of an electric equivalent circuit for a skin type system
F. Gómez-Aguilar; J. Bernal-Alvarado; J. Rosales-García; M. Guía-Calderón; T Córdova-Fraga; M. Sosa-Aquino
In the present work we consider a theoretical representation of an electrical circuit equivalent to a multilayer biological system. The proposed system is of the skin type, containing epidermis, dermis and the subcutaneous tissue. Electrical circuit theory is used, and the behavior of the system is shown in the form of Nyquist and Bode plots. The proposed theoretical approach is a general treatment to describe the bioelectrical transport in a three-layered system, especially in the ele...
Measurements of the vertical atmospheric electric field and of the electrical conductivity with stratospheric balloons
Iversen, I. B.; Madsen, M. M.; Dangelo, N.
Measurements of the atmospheric (vertical) electric field with balloons in the stratosphere are reported. The atmospheric electrical conductivity is also measured and the current density inferred. The average vertical current shows the expected variation with universal time and is also seen to be influenced by external (magnetospheric) electric fields.
Middle atmospheric electric fields over thunderstorms
Holzworth, Robert H.
This grant has supported a variety of investigations all having to do with the external electrodynamics of thunderstorms. The grant was a continuation of work begun while the PI was at the Aerospace Corporation (under NASA Grant NAS6-3109) and the general line of investigation continues today under NASA Grants NAG5-685 and NAG6-111. This report will briefly identify the subject areas of the research and associated results. The period actually covered by the grant NAG5-604 included the following analysis and flights: (1) analysis of five successful balloon flights in 1980 and 1981 (under the predecessor NASA grant) in the stratosphere over thunderstorms; (2) development and flight of the Hy-wire tethered balloon system for direct measurement of the atmospheric potential to 250 kV (this involved multiple tethered balloon flight periods from 1981 through 1986 from several locations including Wallops Island, VA, Poker Flat and Ft. Greely, AK and Holloman AFB, NM.); (3) balloon flights in the stratosphere over thunderstorms to measure vector electric fields and associated parameters in 1986 (2 flights), 1987 (4 flights), and 1988 (2 flights); and (4) rocket-borne optical lightning flash detectors on two rocket flights (1987 and 1988) (the same detector design that was used for the balloon flights listed under #3). In summary this grant supported 8 stratospheric zero-pressure balloon flights, tethered aerostat flights every year between 1982-1985, instruments on 2 rockets, and analysis of data from 6 stratospheric flights in 1980/81.
Global Electric Circuit Diurnal Variation Derived from Storm Overflight and Satellite Optical Lightning Datasets
Mach, Douglas M.; Blakeslee, R. J.; Bateman, M. J.; Bailey, J. C.
We have combined analyses of over 1000 high altitude aircraft observations of electrified clouds with diurnal lightning statistics from the Lightning Imaging Sensor (LIS) and Optical Transient Detector (OTD) to produce an estimate of the diurnal variation in the global electric circuit. Using basic assumptions about the mean storm currents as a function of flash rate and location, and the global electric circuit, our estimate of the current in the global electric circuit matches the Carnegie curve diurnal variation to within 4% for all but two short periods of time. The agreement with the Carnegie curve was obtained without any tuning or adjustment of the satellite or aircraft data. Mean contributions to the global electric circuit from land and ocean thunderstorms are 1.1 kA (land) and 0.7 kA (ocean). Contributions to the global electric circuit from ESCs are 0.22 kA for ocean storms and 0.04 kA for land storms. Using our analysis, the mean total conduction current for the global electric circuit is 2.0 kA.
Enhanced interaction between a mechanical oscillator and two coupled resonant electrical circuits
Dmitriev, A V
This paper reports result of calculation and experimental realization of an electromechanical system that consists of a high-Q mechanical oscillator parametrically coupled in the manner of a capacitive transducer with a RF circuit, which is in turn inductively coupled with another RF circuit. The system operates in the resolved sideband regime when the mechanical oscillator's frequency is larger than the electrical circuits' bandwidths. Using two coupled RF circuits allowed one to enhance the interaction between them and the mechanical oscillator which is one of flexural vibrational modes of a free-edge circular silicon wafer. Such a coupled electromechanical system can be used as a high-sensitive capacitive vibration sensor.
Physics of Atmospheric Electric Discharges in Gases: An Informal Introduction
Treumann, R A; Parrot, M
A short account of the physics of electrical discharges in gases is given in view of its historical evolution and application to planetary atmospheres. As such it serves as an introduction to the articles on particular aspects of electric discharges contained in this book, in particular in the chapters on lightning and the violent discharges which in the recent two decades have been observed to take place in Earth's upper atmosphere. In addition of briefly reviewing the early history of gas discharge physics we discuss the main parameters affecting violent atmospheric discharges like collision frequency, mean free path and critical electric field strength. Any discharge current in the atmosphere is clearly carried only by electrons. Above the lower bound of the mesosphere the electrons must be considered magnetized with the conductivity becoming a tensor. Moreover, the collisional mean free path in the upper atmosphere becomes relatively large which lowers the critical electric field there and more easily ena...
Fabrication and Electrical Characterization of Multiwalled Carbon Nanotube-Based Circuit at Room Temperature
Directory of Open Access Journals (Sweden)
Yitian Peng
Full Text Available Multiwalled carbon nanotube (MWCNT deposited on a pair of predetermined aluminum electrodes treated with the (3-Aminopropyl-triethoxysilane (APTES self-assembled monolayers (SAMs. The MWCNT bridges electrodes and forms electrode/MWCNT/electrode circuit on silicon with 500 nm silicon dioxide. Then the Metal (Ti/Au pads were fabricated on MWCNT to bury the MWCNT into metal electrodes. The electrical properties of MWCNT-based circuits before and after the fabrication of metal pads were characterized. Results indicate that metal pads on MWCNT improved the electrical properties MWCNT-based circuit largely.
A simple atmospheric electrical instrument for educational use
Bennett, A J
Electricity in the atmosphere provides an ideal topic for educational outreach in environmental science. To support this objective, a simple instrument to measure real atmospheric electrical parameters has been developed and its performance evaluated. This project compliments educational activities undertaken by the Coupling of Atmospheric Layers (CAL) European research collaboration. The new instrument is inexpensive to construct and simple to operate, readily allowing it to be used in schools as well as at the undergraduate University level. It is suited to students at a variety of different educational levels, as the results can be analysed with different levels of sophistication. Students can make measurements of the fair weather electric field and current density, thereby gaining an understanding of the electrical nature of the atmosphere. This work was stimulated by the centenary of the 1906 paper in which C.T.R. Wilson described a new apparatus to measure the electric field and conduction current densi...
Developments of a Novel Impedance Matching Circuit for Electrically Small Antennas
Yoshida, K.; Sakaguchi, S.; Oda, S.; Kanaya, H.
In order to reduce the size of a wireless system, we have proposed the design formulas for an electrically small antenna (ESA), i.e. an antenna whose dimension is much smaller than a wavelength, with a miniaturized matching circuit which connects to a 50 ohm external circuit. We designed a slot dipole antenna with the aid of the simulations using the electrical circuits as well as the electromagnetic field (EM field) simulator. The size of the designed antenna including the matching circuit is 4.1 mm × 1.9 mm on MgO substrate with relative permittivity of 9.6 at the center frequency of 5 GHz, and the designed fractional bandwidth is 13%@RL = 3dB. We also made experiments on the slot dipole type ESA with a matching circuit using YBCO thin films on MgO substrates.
Ground-based instrumentation for measurements of atmospheric conduction current and electric field at the South Pole
Byrne, G. J.; Benbrook, J. R.; Bering, E. A.; Few, A. A.; Morris, G. A.; Trabucco, W. J.; Paschal, E. W.
Attention is given to instruments constructed to measure the atmospheric conduction current and the atmospheric electric field - two fundamental parameters of the global-electric circuit. The instruments were deployed at the Amundsen-Scott South Pole Station in January 1991 and are designed to operate continuously for up to one year without operator intervention. The atmospheric current flows into one hemisphere, through the electronics where it is measured, and out the other hemisphere. The electric field is measured by a field mill of the rotating dipole type. Sample data from the first days of operation at the South Pole indicate variations in the global circuit over time scales from minutes to hours to days.
Analysis and calculation of lightning-induced voltages in aircraft electrical circuits
Plumer, J. A.
Techniques to calculate the transfer functions relating lightning-induced voltages in aircraft electrical circuits to aircraft physical characteristics and lightning current parameters are discussed. The analytical work was carried out concurrently with an experimental program of measurements of lightning-induced voltages in the electrical circuits of an F89-J aircraft. A computer program, ETCAL, developed earlier to calculate resistive and inductive transfer functions is refined to account for skin effect, providing results more valid over a wider range of lightning waveshapes than formerly possible. A computer program, WING, is derived to calculate the resistive and inductive transfer functions between a basic aircraft wing and a circuit conductor inside it. Good agreement is obtained between transfer inductances calculated by WING and those reduced from measured data by ETCAL. This computer program shows promise of expansion to permit eventual calculation of potential lightning-induced voltages in electrical circuits of complete aircraft in the design stage.
Teaching Electric Circuits with Multiple Batteries: A Qualitative Approach
Smith, David P.; van Kampen, Paul
We have investigated preservice science teachers' qualitative understanding of circuits consisting of multiple batteries in single and multiple loops using a pretest and post-test method and classroom observations. We found that most students were unable to explain the effects of adding batteries in single and multiple loops, as they tended to use…
Electric Circuits: A New Approach--Part 1.
Shipstone, David; Cheng, Peter C-H.
Shows how box diagrams and AVOW diagrams may be used to solve problems concerning networks of resistors that obey Ohm's Law. Presents outcomes and feedback from students and teachers. Concludes with suggestions as to how these techniques might be incorporated into the teaching of basic circuit theory. (Contains 22 references.) (DDR)
The Use of Enhanced Guided Notes in an Electric Circuit Class: An Exploratory Study
Lawanto, O.
This study was conducted to evaluate students' (n=70) learning performance after their participation in lectures using enhanced guided notes (EGN) in an electric circuits course for non-electrical engineering students. Unlike traditional guided notes, EGN include questions that prompt students to evaluate their metacognitive knowledge. The results…
Atmospheric Breathing Electric Thruster for Planetary Exploration Project
National Aeronautics and Space Administration — This study will investigate the development of an atmosphere-breathing electric propulsion solar-powered vehicle to explore planets such as Mars. The vehicle would...
Self-control of chaos in neural circuits with plastic electrical synapses
Zhigulin, V. P.; Rabinovich, M. I.
Two kinds of connections are known to exist in neural circuits: electrical (also called gap junctions) and chemical. Whereas chemical synapses are known to be plastic (i. e., modifiable), but slow, electrical transmission through gap junctions is not modifiable, but is very fast. We suggest the new artificial synapse that combines the best properties of both: the fast reaction of a gap junction and the plasticity of a chemical synapse. Such a plastic electrical synapse can be used in hybrid neural circuits and for the development of neural prosthetics, i.e., implanted devices that can interact with the real nervous system. Based on the computer modelling we show that such a plastic electrical synapse regularizes chaos in the minimal neural circuit consisting of two chaotic bursting neurons.
Fluctuations of entropy production in partially masked electric circuits
Chiang, Kuan-Hsun; Chou, Chia-Wei; Lee, Chi-Lun; Lai, Pik-Yin; Chen, Yung-Fu
We experimentally investigate fluctuations of entropy production in a coupled driven-RC circuit. In particular, we focus on the hidden-variable problem, where part of the circuit is neglected intentionally. In the two versions of the reduced descriptions we provide for the system, the fluctuation theorem (FT) is valid in all timescales for weak coupling. However, FT fails in the strong-coupling regime, in the short-time limit for one version, and in the long-time limit for the other. In these timescales where FT fails, both descriptions still give FT-like behavior. The failure of FT implies non-Markovian dynamics, meaning there exists a hidden variable that cannot be incorporated into the heat bath. We argue that FT can be restored with the introduction of a timescale-dependent effective noise.
Measuring user similarity using electric circuit analysis: application to collaborative filtering.
Yang, Joonhyuk; Kim, Jinwook; Kim, Wonjoon; Kim, Young Hwan
We propose a new technique of measuring user similarity in collaborative filtering using electric circuit analysis. Electric circuit analysis is used to measure the potential differences between nodes on an electric circuit. In this paper, by applying this method to transaction networks comprising users and items, i.e., user-item matrix, and by using the full information about the relationship structure of users in the perspective of item adoption, we overcome the limitations of one-to-one similarity calculation approach, such as the Pearson correlation, Tanimoto coefficient, and Hamming distance, in collaborative filtering. We found that electric circuit analysis can be successfully incorporated into recommender systems and has the potential to significantly enhance predictability, especially when combined with user-based collaborative filtering. We also propose four types of hybrid algorithms that combine the Pearson correlation method and electric circuit analysis. One of the algorithms exceeds the performance of the traditional collaborative filtering by 37.5% at most. This work opens new opportunities for interdisciplinary research between physics and computer science and the development of new recommendation systems.
Measuring user similarity using electric circuit analysis: application to collaborative filtering.
Directory of Open Access Journals (Sweden)
Joonhyuk Yang
Full Text Available We propose a new technique of measuring user similarity in collaborative filtering using electric circuit analysis. Electric circuit analysis is used to measure the potential differences between nodes on an electric circuit. In this paper, by applying this method to transaction networks comprising users and items, i.e., user-item matrix, and by using the full information about the relationship structure of users in the perspective of item adoption, we overcome the limitations of one-to-one similarity calculation approach, such as the Pearson correlation, Tanimoto coefficient, and Hamming distance, in collaborative filtering. We found that electric circuit analysis can be successfully incorporated into recommender systems and has the potential to significantly enhance predictability, especially when combined with user-based collaborative filtering. We also propose four types of hybrid algorithms that combine the Pearson correlation method and electric circuit analysis. One of the algorithms exceeds the performance of the traditional collaborative filtering by 37.5% at most. This work opens new opportunities for interdisciplinary research between physics and computer science and the development of new recommendation systems.
The induced electric field distribution in the solar atmosphere
Institute of Scientific and Technical Information of China (English)
Rong Chen; Zhi-Liang Yang; Yuan-Yong Deng
A method of calculating the induced electric field is presented.The induced electric field in the solar atmosphere is derived by the time variation of the magnetic field when the accumulation of charged particles is neglected.In order to derive the spatial distribution of the magnetic field,several extrapolation methods are introduced.With observational data from the Helioseismic and Magnetic Imager aboard NASA's Solar Dynamics Observatory taken on 2010 May 20,we extrapolate the magnetic field from the photosphere to the upper atmosphere.By calculating the time variation of the magnetic field,we can get the induced electric field.The derived induced electric field can reach a value of 102 V cm-1 and the average electric field has a maximum point at the layer 360 km above the photosphere.The Monte Carlo method is used to compute the triple integration of the induced electric field.
Importance of Practical Relevance and Design Modules in Electrical Circuits Education
Kalpathy Sundaram; Issa Batarseh; Arthur Weeks; Ruba Akram Amarin
The interactive technical electronic book, TechEBook, currently under development at the University of Central Florida (UCF), provides a useful tool for engineers and scientists through unique features compared to the most used traditional electrical circuit textbooks available in the market. TechEBook has comprised the two worlds of classical circuit books and an interactive operating platform such as iPads, laptops and desktops utilizing Java Virtual Machine operator. The TechEBook provides...
On the modeling of electrical boundary layer (electrode layer) and derivation of atmospheric electrical profiles, eddy diffusion coeffcient and scales of electrode layer
Indian Academy of Sciences (India)
Madhuri N Kulkarni
Electrode layer or electrical boundary layer is one of the charge generators in the global atmospheric electric circuit. In spite of this we find very few model studies and few measurements of it in the literature. Using a new technique it is shown that in this layer, the space charge density varies exponentially in vertical. A new experimental method based on the surface measurements is discussed to determine all the characteristic scales and an average electrical and meteorological state of an electrode layer. The results obtained are in good agreement with the previous studies. So, it is suggested that an exponential space charge density profile will no longer be an assumption in the case of electrode layer studies. The profiles of atmospheric electric field and electrical conductivity are also derived and a new term named as electrode layer constant is introduced.
Stationary and nonstationary models of the global electric circuit: Well-posedness, analytical relations, and numerical implementation
Kalinin, A. V.; Slyunyaev, N. N.; Mareev, E. A.; Zhidkov, A. A.
We analyze the formulation of the problem of global atmospheric electric circuit modeling. It was shown that under some relatively simple and widely used simplifying assumptions this problem can be reduced to finding the temporal and spatial dependencies of the electric potential on the specified generators, which are determined by the external electric current density. They correspond to thunderclouds in the real atmosphere. The ionospheric potential (the potential difference between the upper and lower atmospheric boundaries) is not specified explicitly but can be uniquely determined from the solution. The formulations of the stationary and nonstationary problems are given in terms of the potential and their well-posedness is discussed. We obtained a number of analytical relations under some restrictions on the distribution of conductivity. They include the formulas which explicitly express the ionospheric potential in terms of the problem parameters. The examples of numerical calculations using the software developed on the basis of general formulations of the stationary and nonstationary problems are demonstrated.
Possible Solar Influence On Atmospheric Electric Field
Sikka, P; Murty, A S R; Murty, B V R; Sikka, Poonam; Murty, Bh.V. Ramana; Murty, A S Ramachandra
A cell dynamical system model for the troposphere - ionosphere coupling is proposed . Vertical mass exchange in the troposphere-ionosphere-magnetosphere takes place through a chain of eddy systems. Any perturbation in the troposphere would be transmitted to ionosphere and vice versa. A global perturbation in ionosphere, as the one caused by solar variability, is transmitted to troposphere influencing weather systems/geomagnetic/atmospheric electrification processes.
Simulation of the Universal-Time Diurnal Variation of the Global Electric Circuit Charging Rate
Mackerras, D.; Darvenzia, M.; Orville, R. E.; Williams, E. R.; Goodman, S. J.
A global lightning model that includes diurnal and annual lightning variation, and total flash density versus latitude for each major land and ocean, has been used as the basis for simulating the global electric circuit charging rate. A particular objective has been to reconcile the difference in amplitude ratios [AR=(max-min)/mean] between global lightning diurnal variation (AR approx. = 0.8) and the diurnal variation of typical atmospheric potential gradient curves (AR approx. = 0.35). A constraint on the simulation is that the annual mean charging current should be about 1000 A. The global lightning model shows that negative ground flashes can contribute, at most, about 10-15% of the required current. For the purpose of the charging rate simulation, it was assumed that each ground flash contributes 5 C to the charging process. It was necessary to assume that all electrified clouds contribute to charging by means other than lightning, that the total flash rate can serve as an indirect indicator of the rate of charge transfer, and that oceanic electrified clouds contribute to charging even though they are relatively inefficient in producing lightning. It was also found necessary to add a diurnally invariant charging current component. By trial and error it was found that charging rate diurnal variation curves in Universal time (UT) could be produced with amplitude ratios and general shapes similar to those of the potential gradient diurnal variation curves measured over ocean and arctic regions during voyages of the Carnegie Institute research vessels.
LS1 Report: the electric atmosphere of the LHC
Simon Baird
In the LHC, testing of the main magnet (dipole and quadrupole) circuits has been completed. At the same time, the extensive tests of all the other circuits up to current levels corresponding to 7 TeV beam operation have been performed, and now the final ElQA (Electrical Quality Assurance) tests of the electrical circuits are proceeding. In Sectors 4-5 and 5-6, where the ElQA checks have been finished, the process of removing and storing the helium has started (see the article Heatwave warning for the LHC, in this issue). This is the first step in warming up the whole machine to room temperature so that the main LS1 activities, SMACC (Super Conducting Magnet and Circuit Consolidation) and the R2E (Radiation Two Electronics) programmes, which are scheduled to start on 19 April and 22 March respectively, can get under way. As far as the LHC injectors are concerned, LINAC2 and the PS Booster are in shutdown mode, having completed their preparatory hardware test programmes, and shutdown work has alr...
An atmospheric electrical method to determine the eddy diffusion coefficient
Indian Academy of Sciences (India)
M N Kulkarni; A K Kamra
The ion–aerosol balance equations are solved to get the profiles of atmospheric electric parameters over the ground surface in an aerosol-rich environment under the conditions of surface radioactivity. Combining the earlier results for low aerosol concentrations and the present results for high aerosol concentrations, a relation is obtained between the average value of atmospheric electric space charge in the lowest ∼2m, the surface electric field and eddy diffusivity/aerosol concentration. The values of eddy diffusivity estimated from this method using some earlier measurements of space charge and surface electric field are in reasonably good agreement with those calculated from other standard methods using meteorological or electrical variables.
Development of 3-D Mechanical Models of Electric Circuits and Their Effect on Students' Understanding of Electric Potential Difference
Balta, Nuri
Visualizing physical concepts through models is an essential method in many sciences. While students are mostly proficient in handling mathematical aspects of problems, they frequently lack the ability to visualize and interpret abstract physical concepts in a meaningful way. In this paper, initially the electric circuits and related concepts were…
Atmospheric electric field and current configurations in the vicinity of mountains
Tzur, I.; Roble, R. G.; Adams, J. C.
A number of investigations have been conducted regarding the electrical distortion produced by the earth's orography. Hays and Roble (1979) utilized their global model of atmospheric electricity to study the effect of large-scale orographic features on the currents and fields of the global circuit. The present paper is concerned with an extension of the previous work, taking into account an application of model calculations to orographic features with different configurations and an examination of the electric mapping of these features to ionospheric heights. A two-dimensional quasi-static numerical model of atmospheric electricity is employed. The model contains a detailed electrical conductivity profile. The model region extends from the surface to 100 km and includes the equalization layer located above approximately 70 km. The obtained results show that the electric field and current configurations above mountains depend upon the curvature of the mountain slopes, on the width of the mountain, and on the columnar resistance above the mountain (or mountain height).
Successfully Mapping the U-Tank to an Electric Circuit
Hong, Seok-In
Water-flow analogies are helpful in understanding electricity. For example, in the Lodge model, the constant DC voltage source (a battery) is represented by a U-tank with two water columns of the same cross-sectional area connected by a horizontal duct in which a pump is installed. The pump maintains the difference of the levels of the two water…
Further signatures of long-term changes in atmospheric electrical parameters observed in Europe
Directory of Open Access Journals (Sweden)
F. Märcz
Full Text Available Long-term decreases found recently in both the atmospheric electrical potential gradient (PG and the air-Earth current density (Jz, using observation series from the UK and Hungary, have motivated studies of other European data. Two surface data series somewhat longer than a decade were available: PG data obtained at Serra do Pilar (Portugal, and PG, Jz and positive air conductivity measurements at Athens (Greece. Selecting data to minimise local effects, the 1960–1971 Serra do Pilar PG values decrease at dawn and in the evening. Dawn data obtained at Athens (1967–1977 indicate a reduction in Jz, while the simultaneous PG values there increase (coincident air conductivity values decrease for the periods investigated. The Athens PG increase is attributed to local aerosol influences, typical of urban environments. Despite the urban influence, the Athens Jz shows similarities with soundings of the ionospheric potential. The decline in Jz at Athens occurs simultaneously with a decrease reported previously in Jz at Kew (UK, indicating that, at least, a regional decrease in the global atmospheric electrical circuit occurred during part of the twentieth century. Similar surface changes occur in European atmospheric electrical parameters, with a decrease of about 0.5% to 0.7% per year between 1920 and 1970 (possibly extending back to 1898, an annual decrease of between 2.7 and 3.4%, between 1959 and 1971 and a continued decrease of about ~1% per year between 1967 and 1984, possibly still continuing.
Keywords. Meteorology and atmospheric dynamics (Atmospheric electricity – Geomagnetism and paleomagnetism (Time variations, secular and long term – Atmospheric composition and structure (Aerosols and particles
Electric circuit networks equivalent to chaotic quantum billiards
Bulgakov, Evgeny N.; Maksimov, Dmitrii N.; Sadreev, Almas F.
We formulate two types of electric RLC resonance network equivalent to quantum billiards. In the network of inductors grounded by capacitors squared resonant frequencies are eigenvalues of the quantum billiard. In the network of capacitors grounded by inductors squared resonant frequencies are given by inverse eigen values of the billiard. In both cases local voltages play role of the wave function of the quantum billiard. However as different from quantum billiards there is a heat power beca...
The Stellar-Disk Electric (Short) Circuit: Observational Predictions for a YSO Jet Flow
Liffman, Kurt
We discuss the star-disk electric circuit for a young stellar object (YSO) and calculate the expected torques on the star and the disk. We obtain the same disk magnetic field and star-disk torques as given by standard magnetohydrodynamic (MHD) analysis. We show how a short circuit in the star-disk electric circuit may produce a magnetically-driven jet flow from the inner edge of a disk surrounding a young star. An unsteady bipolar jet flow is produced that flows perpendicular to the disk plane. Jet speeds of order hundreds of kilometres per second are possible, while the outflow mass loss rate is proportional to the mass accretion rate and is a function of the disk inner radius relative to the disk co-rotation radius.
Alignment of atmospheric mineral dust due to electric field
Z. Ulanowski; Bailey, J; Lucas, P.W.; Hough, J.H.; E. Hirst
International audience Optical polarimetry observations on La Palma, Canary Islands, during a Saharan dust episode show dichroic extinction indicating the presence of vertically aligned particles in the atmosphere. Modelling of the extinction together with particle orientation indicates that the alignment could have been due to an electric field of the order of 2 kV/m. Two alternative mechanisms for the origin of the field are examined: the effect of reduced atmospheric conductivity and ch...
Effect of Simple Electric Circuits Teaching on Conceptual Change in Grade 9 Physics Course
Küçüközer, Hüseyin; Kocakülah, Sabri
The aim of this study was to examine the effect of teaching designed to consider grade 9 students' misconceptions about simple electric circuits on conceptual change. Students' misconceptions were determined by using a conceptual understanding test consisting of eight open-ended questions and semi-structured interview technique. Conceptual…
Student Learning in an Electric Circuit Theory Course: Critical Aspects and Task Design
Carstensen, Anna-Karin; Bernhard, Jonte
Understanding time-dependent responses, such as transients, is important in electric circuit theory and other branches of engineering. However, transient response is considered difficult to learn since familiarity with advanced mathematical tools such as Laplace transforms is required. Here, we analyse and describe a novel learning environment…
Development of a Three-Tier Test to Assess Misconceptions about Simple Electric Circuits
Pesman, Haki; Eryilmaz, Ali
The authors aimed to propose a valid and reliable diagnostic instrument by developing a three-tier test on simple electric circuits. Based on findings from the interviews, open-ended questions, and the related literature, the test was developed and administered to 124 high school students. In addition to some qualitative techniques for…
Comparison of Parametrization Techniques for an Electrical Circuit Model of Lithium-Sulfur Batteries
DEFF Research Database (Denmark)
Knap, Vaclav; Stroe, Daniel Loan; Teodorescu, Remus;
on the comparison of different parametrization methods of electrical circuit models (ECMs) for Li-S batteries. These methods are used to parametrize an ECM based on laboratory measurements performed on a Li-S pouch cell. Simulation results of ECMs are presented and compared against measurement values...
Current as the Key Concept of Taiwanese Students' Understandings of Electric Circuits
Tsai, Chia-Hsing; Chen, Hsueh-Yu; Chou, Ching-Yang; Lain, Kuen-Der
The purpose of this study was to report the results of a nationwide survey of Taiwanese high schools students' understandings about electric circuits. The study involved two stratified random samples consisting of 7,145 students in Grades 8 and 9, and 2,857 students in Grade 11, accounting for about 2.3% of the total enrolment in the corresponding…
The Effect of Herrmann Whole Brain Teaching Method on Students' Understanding of Simple Electric Circuits
Bawaneh, Ali Khalid Ali; Nurulazam Md Zain, Ahmad; Salmiza, Saleh
The purpose of this study was to investigate the effect of Herrmann Whole Brain Teaching Method over conventional teaching method on eight graders in their understanding of simple electric circuits in Jordan. Participants (N = 273 students; M = 139, F = 134) were randomly selected from Bani Kenanah region-North of Jordan and randomly assigned to…
An Analysis of Science Textbooks for Grade 6: The Electric Circuit Lesson
Sothayapetch, Pavinee; Lavonen, Jari; Juuti, Kalle
Textbooks are a major tool in the teaching and learning process. This paper presents the results of an analysis of the Finnish and Thai 6th grade science textbooks: electric circuit lesson. Textual and pictorial information from the textbooks were analyzed under four main categories: 1) introduction of the concepts, 2) type of knowledge, 3)…
Encountering the Expertise Reversal Effect with a Computer-Based Environment on Electrical Circuit Analysis
Reisslein, Jana; Atkinson, Robert K.; Seeling, Patrick; Reisslein, Martin
This study examined the effectiveness of a computer-based environment employing three example-based instructional procedures (example-problem, problem-example, and fading) to teach series and parallel electrical circuit analysis to learners classified by two levels of prior knowledge (low and high). Although no differences between the…
Laser cooling and optical detection of excitations in a LC electrical circuit
DEFF Research Database (Denmark)
Taylor, J. M.; Sørensen, Anders Søndberg; Marcus, Charles Masamed;
We explore a method for laser cooling and optical detection of excitations in a room temperature LC electrical circuit. Our approach uses a nanomechanical oscillator as a transducer between optical and electronic excitations. An experimentally feasible system with the oscillator capacitively...
Identifying and Investigating Difficult Concepts in Engineering Mechanics and Electric Circuits. Research Brief
Streveler, Ruth; Geist, Monica; Ammerman, Ravel; Sulzbach, Candace; Miller, Ronald; Olds, Barbara; Nelson, Mary
This study extends ongoing work to identify difficult concepts in thermal and transport science and measure students' understanding of those concepts via a concept inventory. Two research questions provided the focal point: "What important concepts in electric circuits and engineering mechanics do students find difficult to learn?"…
Lessons Learned in the Use of WIRIS Quizzes to Upgrade Moodle to Solve Electrical Circuits
Bogarra Rodriguez, S.; Corbalan Fuertes, M.; Font Piera, A.; Plaza Garcia, I.; Solsona, F. J. A.
WIRIS quizzes are an online mathematics tool for educational purposes that upgrade Moodle quizzes and allow the development of personalized quizzes using random data and conditional instructions. WIRIS quizzes can be used in any mathematics or science degree; their complex operators allow it to be used to solve electrical circuits. This tool…
A simple atmospheric electrical instrument for educational use
Bennett, A. J.; Harrison, R. G.
Electricity in the atmosphere provides an ideal topic for educational outreach in environmental science. To support this objective, a simple instrument to measure real atmospheric electrical parameters has been developed and its performance evaluated. This project compliments educational activities undertaken by the Coupling of Atmospheric Layers (CAL) European research collaboration. The new instrument is inexpensive to construct and simple to operate, readily allowing it to be used in schools as well as at the undergraduate University level. It is suited to students at a variety of different educational levels, as the results can be analysed with different levels of sophistication. Students can make measurements of the fair weather electric field and current density, thereby gaining an understanding of the electrical nature of the atmosphere. This work was stimulated by the centenary of the 1906 paper in which C. T. R. Wilson described a new apparatus to measure the electric field and conduction current density. Measurements using instruments based on the same principles continued regularly in the UK until 1979. The instrument proposed is based on the same physical principles as C. T. R. Wilson's 1906 instrument.
A simple atmospheric electrical instrument for educational use
Directory of Open Access Journals (Sweden)
A. J. Bennett
Full Text Available Electricity in the atmosphere provides an ideal topic for educational outreach in environmental science. To support this objective, a simple instrument to measure real atmospheric electrical parameters has been developed and its performance evaluated. This project compliments educational activities undertaken by the Coupling of Atmospheric Layers (CAL European research collaboration. The new instrument is inexpensive to construct and simple to operate, readily allowing it to be used in schools as well as at the undergraduate University level. It is suited to students at a variety of different educational levels, as the results can be analysed with different levels of sophistication. Students can make measurements of the fair weather electric field and current density, thereby gaining an understanding of the electrical nature of the atmosphere. This work was stimulated by the centenary of the 1906 paper in which C. T. R. Wilson described a new apparatus to measure the electric field and conduction current density. Measurements using instruments based on the same principles continued regularly in the UK until 1979. The instrument proposed is based on the same physical principles as C. T. R. Wilson's 1906 instrument.
Wireless Electrical Device Using Open-Circuit Elements Having No Electrical Connections
Woodard, Stanley E. (Inventor); Taylor, Bryant Douglas (Inventor)
A wireless electrical device includes an electrically unconnected electrical conductor and at least one electrically unconnected electrode spaced apart from the electrical conductor. The electrical conductor is shaped for storage of an electric field and a magnetic field. In the presence of a time-varying magnetic field, the electrical conductor so-shaped resonates to generate harmonic electric and magnetic field responses. Each electrode is at a location lying within the magnetic field response so-generated and is constructed such that a linear movement of electric charges is generated in each electrode due to the magnetic field response so-generated.
Physical proof of the occurrence of the Braess Paradox in electrical circuits
Nagurney, Ladimer S.; Nagurney, Anna
The Braess Paradox is the counterintuitive phenomenon that can occur in a user-optimized network system, such as a transportation network, where adding an additional link to the network increases the cost (travel time) for every user. In electrical circuits, electrons, analogous to drivers in a transportation network, traverse the network so that no electron can unilaterally change its cost (voltage drop) from an origin to a destination. In this paper, we show that the Braess Paradox can occur in electrical circuits consisting of diodes and resistors. We report measurements confirming the occurrence of the Braess Paradox in two different circuits, one with highly nonlinear link cost functions (I\\text-V characteristics). These measurements show that the voltage increases, rather than decreases, when a link is added to the circuit under constant demand (current). This discovery identifies novel circuits in which the voltage and current can be independently adjusted. It also yields insights into the Braess Paradox and transportation networks through a new computational mechanism.
Circuit models of the passive electrical properties of frog skeletal muscle fibers.
Valdiosera, R; Clausen, C; Eisenberg, R S
The relation between the fine structure, electric field equations, and electric circuit models of skeletal muscle fibers is discussed. Experimental evidence illustrates the profound variation of potential with circumferential position, even at low frequencies (100 Hz). Since one-dimensional cable theory cannot account for such variation, three-dimensional cable theory must be used. Several circuit models of a sarcomere are presented and plots are made of the predicted phase angle between sinusoidal applied current and potential. The circuit models are described by equations involving normalized variables, since they affect the phase plot in a relatively simple way. A method is presented for estimating the values of the circuit elements and the standard deviation of the estimates. The reliability of the estimates is discussed. An objective measure of fit, Hamilton's R test, is used to test the significance of different fits to data. Finally, it is concluded that none of the proposed circuit models provides an adequate description of the observed variation of phase angle with circumferential location. It is not clear whether the source of disagreement is inadequate measurements or inadequate theory.
Earth's Atmospheric Electricity Parameter Response During Venus Transit
Directory of Open Access Journals (Sweden)
Syam Sundar De
Full Text Available Venus transited across the Sun on 06 June 2012, introducing significant contribution to the tidal characteristics of the solar atmosphere. _ atmosphere was perturbed due to an anomalous Coronal Mass Ejection (CME and γ-radiationγ-radiation influenced by the solar tide due to Venus transit, thereby the Earth-ionosphere waveguide characteristics were changed. In this anomalous situation we measured some atmospheric electricity parameters such as Schumann resonance (SR amplitude, very low frequency (VLF sferics, subionospheric transmitted signals and the point discharge current (PDC along with the vertical electrical potential gradient (PG at the ground surface on the day of transit. The results showed some remarkable variations during the transit as well as pre- and post-transit periods. The observed anomalies in the recorded data were interpreted in terms of the anomalous solar tidal effects initiated due to Venus transit.
Background voltage distortion influence on power electric systems in the presence of the Steinmetz circuit
Energy Technology Data Exchange (ETDEWEB)
Sainz, Luis; Pedra, Joaquin [Department of Electrical Engineering, ETSEIB-UPC, Av. Diagonal 647, 08028 Barcelona (Spain); Caro, Manuel [IDOM Ingenieria y Arquitectura, C. Barcas 2, 46002 Valencia (Spain)
In traction systems, it is usual to connect reactances in delta configuration with single-phase loads to reduce voltage unbalances and avoid electric system operation problems. This set is known as Steinmetz circuit. Parallel and series resonances can occur due to the capacitive reactance of the Steinmetz circuit and affect power quality. In this paper, the series resonance ''observed'' from the supply system is numerically located. The study of this resonance is important to avoid problems due to background voltage distortion. Experimental measurements are also presented to validate the obtained numerical results. (author)
Electrically Small Resonators for Planar Metamaterial, Microwave Circuit and Antenna Design: A Comparative Analysis
Directory of Open Access Journals (Sweden)
Miguel Durán-Sindreu
Full Text Available Planar metamaterials and many microwave circuits and antennas are designed by means of resonators with dimensions much smaller than the wavelength at their resonance frequency. There are many types of such electrically small resonators, and the main purpose of this paper is to compare them as building blocks for the implementation of microwave components. Aspects such as resonator size, bandwidth, their circuit models when they are coupled to transmission lines (as is usually required, as well as key applications, will be considered.
Importance of Practical Relevance and Design Modules in Electrical Circuits Education
Directory of Open Access Journals (Sweden)
Kalpathy Sundaram
Full Text Available The interactive technical electronic book, TechEBook, currently under development at the University of Central Florida (UCF, provides a useful tool for engineers and scientists through unique features compared to the most used traditional electrical circuit textbooks available in the market. TechEBook has comprised the two worlds of classical circuit books and an interactive operating platform such as iPads, laptops and desktops utilizing Java Virtual Machine operator. The TechEBook provides an interactive applets screen that holds many modules, in which each had a specific application in the self learning process. This paper describes two of the interactive techniques in the TechEBook known as, Practical Relevance Modules (PRM and Design Modules (DM. The Practical Relevance Module will assist the readers to learn electrical circuit analysis and to understand the practical application of the electrical network theory through solving real world examples and problems. The Design Module will help students design real-life problems. These modules will be displayed after each section in the TechEBook for the user to relate his/her understanding with the outside world, which introduces the term me-applying and me-designing, as a comprehensive full experience for self or individualized education. The main emphasis of this paper is the PRM while the DM will be discussed in brief. A practical example of applying the PRM and DM features is discussed as part of a basic electrical engineering course currently given at UCF and results show improved student performances in learning materials in Electrical Circuits. In the future, such modules can be redesigned to become highly interactive with illustrated animations.
Wireless Open-Circuit In-Plane Strain and Displacement Sensor Requiring No Electrical Connections
Woodard, Stanley E. (Inventor)
A wireless in-plane strain and displacement sensor includes an electrical conductor fixedly coupled to a substrate subject to strain conditions. The electrical conductor is shaped between its ends for storage of an electric field and a magnetic field, and remains electrically unconnected to define an unconnected open-circuit having inductance and capacitance. In the presence of a time-varying magnetic field, the electrical conductor so-shaped resonates to generate harmonic electric and magnetic field responses. The sensor also includes at least one electrically unconnected electrode having an end and a free portion extending from the end thereof. The end of each electrode is fixedly coupled to the substrate and the free portion thereof remains unencumbered and spaced apart from a portion of the electrical conductor so-shaped. More specifically, at least some of the free portion is disposed at a location lying within the magnetic field response generated by the electrical conductor. A motion guidance structure is slidingly engaged with each electrode's free portion in order to maintain each free portion parallel to the electrical conductor so-shaped.
Observations of ionospheric electric fields above atmospheric weather systems
Farrell, W. M.; Aggson, T. L.; Rodgers, E. B.; Hanson, W. B.
We report on the observations of a number of quasi-dc electric field events associated with large-scale atmospheric weather formations. The observations were made by the electric field experiment onboard the San Marco D satellite, operational in an equatorial orbit from May to December 1988. Several theoretical studies suggest that electric fields generated by thunderstorms are present at high altitudes in the ionosphere. In spite of such favorable predictions, weather-related events are not often observed since they are relatively weak. We shall report here on a set of likely E field candidates for atmospheric-ionospheric causality, these being observed over the Indonesian Basin, northern South America, and the west coast of Africa; all known sites of atmospheric activity. As we shall demonstrate, individual events often be traced to specific active weather features. For example, a number of events were associated with spacecraft passages near Hurricane Joan in mid-October 1988. As a statistical set, the events appear to coincide with the most active regions of atmospheric weather.
Examining students' understanding of electrical circuits through multiple-choice testing and interviews
Engelhardt, Paula Vetter
Research has shown that both high school and university students have misconceptions about direct current resistive electric circuits. At present, there are no standard diagnostic examinations in electric circuits. Such an instrument would be useful in determining what conceptual problems students have either before or after instruction. The information provided by the exam can be used by classroom instructors to evaluate their instructional methods and the progress and conceptual problems of their students. It can be used to evaluate curricular packages and/or other supplemental materials for their effectiveness in overcoming students' conceptual difficulties. Two versions of a diagnostic instrument known as Determining and Interpreting Resistive Electric circuits Concepts Tests (DIRECT) were developed, each consisting of 29 questions. DIRECT was administered to groups of high school and university students in the United States, Canada and Germany. The students had completed their study of electrostatics and direct current electric circuits prior to taking the exam. Individual interviews were conducted after the administration of version 1.0 to determine how students were interpreting the questions and to uncover their reasoning behind their selections. The analyses indicate that students, especially females, tend to hold multiple misconceptions, even after instruction. The idea that the battery is a constant source of current was used most often in answering the questions. Although students tend to use different misconceptions for each question presented, they do use misconceptions associated with the global objective of the question. Students' definitions of terms used on the exam and their misconceptions were examined. Students tended to confuse terms, especially current. They assigned the properties of current to voltage and/or resistance. One of the major findings from the study was that students were able to translate easily from a "realistic" representation
Simulation of Higher-Order Electrical Circuits with Stochastic Parameters via SDEs
Directory of Open Access Journals (Sweden)
Full Text Available The paper deals with a technique for the simulation of higher-order electrical circuits with parameters varying randomly. The principle consists in the utilization of the theory of stochastic differential equations (SDE, namely the vector form of the ordinary SDEs. Random changes of both excitation voltage and some parameters of passive circuit elements are considered, and circuit responses are analyzed. The voltage and/or current responses are computed and represented in the form of the sample means accompanied by their confidence intervals to provide reliable estimates. The method is applied to analyze responses of the circuit models of optional orders, specially those consisting of a cascade connection of the RLGC networks. To develop the model equations the state-variable method is used, afterwards a corresponding vector SDE is formulated and a stochastic Euler numerical method applied. To verify the results the deterministic responses are also computed by the help of the PSpice simulator or the numerical inverse Laplace transforms (NILT procedure in MATLAB, while removing random terms from the circuit model.
Equivalent circuits for electrically small antennas using LS-decomposition with the method of moments
Simpson, T. L.; Logan, James C.; Rockway, John W.
As part of an investigation into methods for accelerating the process of filling the method-of-moments impedance matrix (Z), it was found that (Z) could be decomposed into three parts: a real inductance matrix (L) from the magnetostatic vector potential, a real elastance (inverse capacitance) matrix (S) from the electrostatic static scalar potential, and a complex impedance matrix (z/omega/) of residual frequency-dependent contributions. By neglecting (z/omega/) at sufficiently low frequencies, static and quasi-static charge and current distributions were obtained. For electrically small antennas, a complete RLC circuit was obtained directly from a single quasi-static solution rather than as an approximate characterization of the impedance as a function of frequency. This gives a precise definition of the circuit parameters limiting the performance of electrically small antennas.
An Empirical Model for Estimating the Probability of Electrical Short Circuits from Tin Whiskers. Part 2
Courey, Karim; Wright, Clara; Asfour, Shihab; Onar, Arzu; Bayliss, Jon; Ludwig, Larry
In this experiment, an empirical model to quantify the probability of occurrence of an electrical short circuit from tin whiskers as a function of voltage was developed. This empirical model can be used to improve existing risk simulation models. FIB and TEM images of a tin whisker confirm the rare polycrystalline structure on one of the three whiskers studied. FIB cross-section of the card guides verified that the tin finish was bright tin.
Large amplitude middle atmospheric electric fields - Fact or fiction?
Kelley, M. C.; Siefring, C. L.; Pfaff, R. F., Jr.
An analysis of the measurements of large apparent dc fields in the middle atmosphere, previously gathered by two sounding rockets, shows these fields to be spurious. In the case of one of the rockets, the evidence presented suggests that the measured electric fields, aligned with the rocket's velocity vector, may be due to a negatively charged wake. A comparison of measurements made by various electric field booms also suggests that the insulating boom coatings in one experiment may have affected the results obtained. It is recommended that insulating coatings should not be used at mesospheric altitudes, because of the detrimental effects that frictional charging may have.
Detection and location of electrical insulation faults on the LHC superconducting circuits during hardware commissioning
Bozzini, D; Mess, K H; Russenschuck, Stephan
As part of the electrical quality assurance program (ELQA), the insulation of all superconducting circuits of the LHC has to be tested with a d.c. voltage of up to 1.9 kV. Fault location within a ± 3 m range over the total length of 2700 m has been achieved in order to limit the number of interconnection openings for repair. In this paper, the methods, tooling, and procedures for the detection and location of electrical faults will be presented in view of the practical experience gained in the LHC tunnel. Three particular cases of localized faults during LHC hardware commissioning will be discussed.
Development and Implementation of an Electric Circuits On-Line Course
Directory of Open Access Journals (Sweden)
Ahmed Hussain
Full Text Available An electric circuit on-line course has been developed at KFUPM to support student centered learning. The course has been used in the first stage to supplement the class room face-to-face instruction. This paper describes the development stages of the on-line course and highlights its fundamental features that are not available in the traditional methods of instruction. The paper also includes the results of a survey conducted among students who have utilized the on-line material to supplement their traditional study of the electric circuits' course. The results of the survey showed a general satisfaction with the course content and the instructional effectiveness.
Parameterization of electrical equivalent circuits for pem fuel cells; Parametrierung elektrischer Aequivalentschaltbilder von PEM Brennstoffzellen
Energy Technology Data Exchange (ETDEWEB)
Haubrock, J.
Fuel cells are a very promising technology for energy conversion. For optimization purpose, useful simulation tools are needs. Simulation tools should simulate the static and dynamic electrical behaviour and the models should parameterized by measurment results which should be done easily. In this dissertation, a useful model for simulating a pem fuel cell is developed. the model should parametrizes by V-I curve measurment and by current step respond. The model based on electrical equivalent circuits and it is shown, that it is possible to simulate the dynamic behaviour of a pem fuel cell stack. The simulation results are compared by measurment results. (orig.)
A joint dataset of fair-weather atmospheric electricity
Tammet, H.
A new open access dataset ATMEL2007A ( http://ael.physic.ut.ee/tammet/dd/) takes advantage of the diary-type data structure. The dataset comprises the measurements of atmospheric electric field, positive and negative conductivities, air ion concentrations and accompanying meteorological measurements at 13 stations, including 7 stations of the former World Data Centre network. The dataset incorporates more than half a million diurnal series of hourly averages and it can easily be expanded with additional data. The dataset is designed for importing into a personal computer, which makes possible the appending of private data and safely protecting it from public access. Available free software allows extracting data excerpts in the form of traditional data tables or spreadsheets. Examples show how the dataset can be used in the research of the correlations and trends in atmospheric electricity and air pollution.
Alignment of atmospheric mineral dust due to electric field
Directory of Open Access Journals (Sweden)
Z. Ulanowski
Full Text Available Optical polarimetry observations on La Palma, Canary Islands, during a Saharan dust episode show dichroic extinction indicating the presence of vertically aligned particles in the atmosphere. Modelling of the extinction together with particle orientation indicates that the alignment could have been due to an electric field of the order of 2 kV/m. Two alternative mechanisms for the origin of the field are examined: the effect of reduced atmospheric conductivity and charging of the dust layer, the latter effect being a more likely candidate. It is concluded that partial alignment may be a common feature of Saharan dust layers. The modelling indicates that the alignment can significantly alter dust optical depth. This "Venetian blind effect" may have decreased optical thickness in the vertical direction by as much as 10% for the case reported here. It is also possible that the alignment and the electric field modify dust transport.
Alignment of atmospheric mineral dust due to electric field
Ulanowski, Z.; Bailey, J.; Lucas, P. W.; Hough, J. H.; Hirst, E.
Optical polarimetry observations on La Palma, Canary Islands, during a Saharan dust episode show dichroic extinction indicating the presence of vertically aligned particles in the atmosphere. Modelling of the extinction together with particle orientation indicates that the alignment could have been due to an electric field of the order of 2 kV/m. Two alternative mechanisms for the origin of the field are examined: the effect of reduced atmospheric conductivity and charging of the dust layer, the latter effect being a more likely candidate. It is concluded that partial alignment may be a common feature of Saharan dust layers. The modelling indicates that the alignment can significantly alter dust optical depth. This "Venetian blind effect" may have decreased optical thickness in the vertical direction by as much as 10% for the case reported here. It is also possible that the alignment and the electric field modify dust transport.
Fairweather atmospheric electricity at Antarctica during local summer as observed from Indian station, Maitri
Indian Academy of Sciences (India)
C Panneerselvam; C Selvaraj; K Jeeva; K U Nair; C P Anilkumar; S Gurubaran
Surface measurements of the atmospheric electrical parameters like Maxwell current, electric field and conductivity studied at the Indian station, Maitri (70.75°S, 11.75°E, 117m above mean sea level), Antarctica, during austral summer have been analyzed for the years 2001 to 2004. A total of 69 days were selected which satisfied the 'fairweather' conditions, i.e., days with absence of high winds, drifting or falling snow, clouds, and fog effects. The diurnal variation curve of electric field and vertical current averaged for 69 fairweather days is a single periodic with a minimum at 03:00UT and a maximum near 19:00UT, which is very similar to the Carnegie curve. The correlation coefficient between these measured parameters has a high value (more than 0.9) for all the days. During fairweather days the measured current and field variations are similar and hence it is clear that the conductivity is more or less stable. During magnetically disturbed days, the dawn-dusk potential drop has clear influences on the diurnal variation and it modifies the conductivity. Apart from the day-to-day variation in low latitude thunderstorm activity, there are diurnal, seasonal, inter-annual variations in the electric potential and the currents, as well as solar influences on the measured parameters. This study will help us to examine the impact of solar and geophysical phenomena like solar flares, geomagnetic storms and substorms on the global electric circuit.
Effect of atmospheric electricity on dry deposition of airborne particles from atmosphere
Tammet, H.; Kimmel, V.; Israelsson, S.
The electric mechanism of dry deposition is well known in the case of unattached radon daughter clusters that are unipolar charged and of high mobility. The problematic role of the electric forces in deposition of aerosol particles is theoretically examined by comparing the fluxes of particles carried by different deposition mechanisms in a model situation. The electric mechanism of deposition appears essential for particles of diameter 10-200 nm in conditions of low wind speed. The electric flux of fine particles can be dominant on the tips of leaves and needles even in a moderate atmospheric electric field of a few hundred V m -1 measured over the plane ground surface. The electric deposition is enhanced under thunderclouds and high voltage power lines. Strong wind suppresses the relative role of the electric deposition when compared with aerodynamic deposition. When compared with diffusion deposition the electric deposition appears less uniform: the precipitation particulate matter on the tips of leaves and especially on needles of top branches of conifer trees is much more intensive than on the ground surface and electrically shielded surfaces of plants. The knowledge of deposition geometry could improve our understanding of air pollution damage to plants.
Full wave analysis of non-radiative dielectric waveguide modulator for the determination of electrical equivalent circuit
Indian Academy of Sciences (India)
N P Pathak; A Basu; S K Koul
This paper reports the determination of electrical equivalent circuit of ON/OFF modulator in non-radiative dielectric (NRD) guide configurations at Ka-band. Schottky barrier mixer diode is used to realize this modulator and its characteristics are determined experimentally using vector network analyzer. Full wave FEM simulator HFSS is used to determine an equivalent circuit for the mounted diode and modulator in ON and OFF states. This equivalent circuit is used to qualitatively explain the experimental characteristics of modulator.
Effects of extraordinary solar cosmic ray events on variations in the atmospheric electric field at high latitudes
Shumilov, O. I.; Kasatkina, E. A.; Frank-Kamenetsky, A. V.
Studies of variations in the atmospheric electric field vertical component ( E z ) are illustrated based on data from the Apatity high-latitude observatory (geomagnetic latitude Φ' = 63.8°) for three solar cosmic ray (SCR) events that occurred on April 15, April 18, and November 4, 2001. For the SCR event of April 15, 2001, the observed E z variations have been compared with the corresponding data from the Voeykovo midlatitude observatory and the Vostok observatory on the polar cap. It has been indicated that solar coronal mass ejections and some powerful SCR events can result in variations in the global electric circuit. Disturbances in the atmospheric electric field can be used to diagnose the development of intense processes on the Sun.
Monte Carlo simulations of air showers in atmospheric electric fields
Buitink, S; Falcke, H; Heck, D; Kuijpers, J
The development of cosmic ray air showers can be influenced by atmospheric electric fields. Under fair weather conditions these fields are small, but the strong fields inside thunderstorms can have a significant effect on the electromagnetic component of a shower. Understanding this effect is particularly important for radio detection of air showers, since the radio emission is produced by the shower electrons and positrons. We perform Monte Carlo simulations to calculate the effects of different electric field configurations on the shower development. We find that the electric field becomes important for values of the order of 1 kV/cm. Not only can the energy distribution of electrons and positrons change significantly for such field strengths, it is also possible that runaway electron breakdown occurs at high altitudes, which is an important effect in lightning initiation.
On-chip detection circuit for protection design in display panel against electrical fast transient (EFT) disturbance
International Nuclear Information System (INIS)
A new on-chip detection circuit is proposed for electrical fast transient (EFT) protection design in a display system. For microelectronic products, electrical transient disturbances often cause upset or frozen states under the IEC test standard. The output signal of the proposed detection circuit can be used as a firmware index to execute system automatic recovery operations and to release the EFT-induced locked states in display panels. The circuit function to detect positive or negative electrical transients has been investigated in HSPICE simulation and verified in silicon chip. The experimental results have confirmed successful circuit performance under EFT tests. With hardware/firmware co-design, the immunity of a display system against electrical transient disturbance has been significantly improved.
Discharge processes and an electrical model of atmospheric pressure plasma jets in argon
Fang, Zhi; Shao, Tao; Yang, Jing; Zhang, Cheng
In this paper, an atmospheric pressure plasma discharge in argon was generated using a needle-to-ring electrode configuration driven by a sinusoidal excitation voltage. The electric discharge processes and discharge characteristics were investigated by inspecting the voltage-current waveforms, Lissajous curves and lighting emission images. The change in discharge mode with applied voltage amplitude was studied and characterised, and three modes of corona discharge, dielectric barrier discharge (DBD) and jet discharge were identified, which appeared in turn with increasing applied voltage and can be distinguished clearly from the measured voltage-current waveforms, light-emission images and the changing gradient of discharge power with applied voltage. Based on the experimental results and discharge mechanism analysis, an equivalent electrical model and the corresponding equivalent circuit for characterising the whole discharge processes accurately was proposed, and the three discharge stages were characterised separately. A voltage-controlled current source (VCCS) associated with a resistance and a capacitance were used to represent the DBD stage, and the plasma plume and corona discharge were modelled by a variable capacitor in series with a variable resistor. Other factors that can influence the discharge, such as lead and stray capacitance values of the circuit, were also considered in the proposed model. Contribution to the Topical Issue "Recent Breakthroughs in Microplasma Science and Technology", edited by Kurt Becker, Jose Lopez, David Staack, Klaus-Dieter Weltmann and Wei Dong Zhu.
Identification of a Retinal Circuit for Recurrent Suppression Using Indirect Electrical Imaging.
Greschner, Martin; Heitman, Alexander K; Field, Greg D; Li, Peter H; Ahn, Daniel; Sher, Alexander; Litke, Alan M; Chichilnisky, E J
Understanding the function of modulatory interneuron networks is a major challenge, because such networks typically operate over long spatial scales and involve many neurons of different types. Here, we use an indirect electrical imaging method to reveal the function of a spatially extended, recurrent retinal circuit composed of two cell types. This recurrent circuit produces peripheral response suppression of early visual signals in the primate magnocellular visual pathway. We identify a type of polyaxonal amacrine cell physiologically via its distinctive electrical signature, revealed by electrical coupling with ON parasol retinal ganglion cells recorded using a large-scale multi-electrode array. Coupling causes the amacrine cells to fire spikes that propagate radially over long distances, producing GABA-ergic inhibition of other ON parasol cells recorded near the amacrine cell axonal projections. We propose and test a model for the function of this amacrine cell type, in which the extra-classical receptive field of ON parasol cells is formed by reciprocal inhibition from other ON parasol cells in the periphery, via the electrically coupled amacrine cell network. PMID:27397894
The impact of the conceptual change model on grade 10 learners using simple electric circuits / Mmaletsegetla Paulus Manabile
Manabile, Mmaletsegetla Paulus
Poor academic performance in science is a problem in the world. Numbers of factors contribute to this academic performance. Secondary school learners, particularly those in grade 10 are experiencing problems in understanding simple electric circuits in Physical Sciences. Lack of exposure to practical work might be one of the factors that contribute to lack of understanding of simple electric circuit and inability to link what they learn in class with the outside world. For that reason, it ...
Complicated Electric Circuit P-T Calculus Model Based on VHDL%基于VHDL的复杂电路的P-T算法模型
Institute of Scientific and Technical Information of China (English)
刘丹非; 李曼义; 郭金怀
When we design electric circuit with the hardware describe language VHDL,if the control of the electriccircuit is more than to calculate,we can design electric circuit as a controller which is based on multiplexer and is di-vided into the space part and the time part. Electric circuit is synthesized and form CPLD or FPGA circuit by adjustingthe P- T arithmetic model. We explain this method by designing the controller of CPU as a example.
Electrically detected magnetic resonance modeling and fitting: An equivalent circuit approach
Energy Technology Data Exchange (ETDEWEB)
Leite, D. M. G., E-mail: email@example.com [UNIFEI—Universidade Federal de Itajubá, Av. BPS, 1303, 37500-903 Itajubá, MG (Brazil); Batagin-Neto, A.; Nunes-Neto, O. [UNESP—Univ Estadual Paulista, POSMAT—Programa de Pós-Graduação em Ciência e Tecnologia de Materiais, Av. Eng. Luiz Edmundo Carrijo Coube, 14-01, 17033-360 Bauru, SP (Brazil); Gómez, J. A. [Departamento de Física, FFCLRP-USP, Av. Bandeirantes 3900, 14040-901 Ribeirão Preto, SP (Brazil); Graeff, C. F. O. [UNESP—Univ Estadual Paulista, POSMAT—Programa de Pós-Graduação em Ciência e Tecnologia de Materiais, Av. Eng. Luiz Edmundo Carrijo Coube, 14-01, 17033-360 Bauru, SP (Brazil); DF-FC, UNESP—Univ Estadual Paulista, Av. Eng. Luiz Edmundo Carrijo Coube, 14-01, 17033-360 Bauru, SP (Brazil)
The physics of electrically detected magnetic resonance (EDMR) quadrature spectra is investigated. An equivalent circuit model is proposed in order to retrieve crucial information in a variety of different situations. This model allows the discrimination and determination of spectroscopic parameters associated to distinct resonant spin lines responsible for the total signal. The model considers not just the electrical response of the sample but also features of the measuring circuit and their influence on the resulting spectral lines. As a consequence, from our model, it is possible to separate different regimes, which depend basically on the modulation frequency and the RC constant of the circuit. In what is called the high frequency regime, it is shown that the sign of the signal can be determined. Recent EDMR spectra from Alq{sub 3} based organic light emitting diodes, as well as from a-Si:H reported in the literature, were successfully fitted by the model. Accurate values of g-factor and linewidth of the resonant lines were obtained.
Global Electric Circuit Implications of Combined Aircraft Storm Electric Current Measurements and Satellite-Based Diurnal Lightning Statistics
Mach, Douglas M.; Blakeslee, Richard J.; Bateman, Monte G.
Using rotating vane electric field mills and Gerdien capacitors, we measured the electric field profile and conductivity during 850 overflights of thunderstorms and electrified shower clouds (ESCs) spanning regions including the Southeastern United States, the Western Atlantic Ocean, the Gulf of Mexico, Central America and adjacent oceans, Central Brazil, and the South Pacific. The overflights include storms over land and ocean, and with positive and negative fields above the storms. Over three-quarters (78%) of the land storms had detectable lightning, while less than half (43%) of the oceanic storms had lightning. Integrating our electric field and conductivity data, we determined total conduction currents and flash rates for each overpass. With knowledge of the storm location (land or ocean) and type (with or without lightning), we determine the mean currents by location and type. The mean current for ocean thunderstorms is 1.7 A while the mean current for land thunderstorms is 1.0 A. The mean current for ocean ESCs 0.41 A and the mean current for land ESCs is 0.13 A. We did not find any significant regional or latitudinal based patterns in our total conduction currents. By combining the aircraft derived storm currents and flash rates with diurnal flash rate statistics derived from the Lightning Imaging Sensor (LIS) and Optical Transient Detector (OTD) low Earth orbiting satellites, we reproduce the diurnal variation in the global electric circuit (i.e., the Carnegie curve) to within 4% for all but two short periods of time. The agreement with the Carnegie curve was obtained without any tuning or adjustment of the satellite or aircraft data. Given our data and assumptions, mean contributions to the global electric circuit are 1.1 kA (land) and 0.7 kA (ocean) from thunderstorms, and 0.22 kA (ocean) and 0.04 (land) from ESCs, resulting in a mean total conduction current estimate for the global electric circuit of 2.0 kA. Mean storm counts are 1100 for land
Global Electric Circuit Implications of Total Current Measurements over Electrified Clouds
Mach, Douglas M.; Blakeslee, Richard J.; Bateman, Monte G.
We determined total conduction (Wilson) currents and flash rates for 850 overflights of electrified clouds spanning regions including the Southeastern United States, the Western Atlantic Ocean, the Gulf of Mexico, Central America and adjacent oceans, Central Brazil, and the South Pacific. The overflights include storms over land and ocean, with and without lightning, and with positive and negative Wilson currents. We combined these individual storm overflight statistics with global diurnal lightning variation data from the Lightning Imaging Sensor (LIS) and Optical Transient Detector (OTD) to estimate the thunderstorm and electrified shower cloud contributions to the diurnal variation in the global electric circuit. The contributions to the global electric circuit from lightning producing clouds are estimated by taking the mean current per flash derived from the overflight data for land and ocean overflights and combining it with the global lightning rates (for land and ocean) and their diurnal variation derived from the LIS/OTD data. We estimate the contribution of non-lightning producing electrified clouds by assuming several different diurnal variations and total non-electrified storm counts to produce estimates of the total storm currents (lightning and non-lightning producing storms). The storm counts and diurnal variations are constrained so that the resultant total current diurnal variation equals the diurnal variation in the fair weather electric field (+/-15%). These assumptions, combined with the airborne and satellite data, suggest that the total mean current in the global electric circuit ranges from 2.0 to 2.7 kA, which is greater than estimates made by others using other methods.
Reconfigurable anisotropy and functional transformations with VO$_{2}$-based metamaterial electric circuits
Savo, Salvatore; Castaldi, Giuseppe; Moccia, Massimo; Galdi, Vincenzo; Ramanathan, Shriram; Sato, Yuki
We demonstrate an innovative multifunctional artificial material that combines exotic metamaterial properties and the environmentally responsive nature of phase change media. The tunable metamaterial is designed with the aid of two interwoven coordinate-transformation equations and implemented with a network of thin film resistors and vanadium dioxide ($VO_{2}$). The strong temperature dependence of $VO_{2}$ electrical conductivity results in a relevant modification of the resistor network behavior, and we provide experimental evidence for a reconfigurable metamaterial electric circuit (MMEC) that not only mimics a continuous medium but is also capable of responding to thermal stimulation through dynamic variation of its spatial anisotropy. Upon external temperature change the overall effective functionality of the material switches between a "truncated-cloak" and "concentrator" for electric currents. Possible applications may include adaptive matching resistor networks, multifunctional electronic devices, an...
An Overview of Peach, the Atmospheric Electricity Component of Hymex
Defer, E.; Coquillat, S.; Pinty, J.; Soula, S.; Martin, J.; Prieur, S.; Richard, E.; Rison, W.; Krehbiel, P. R.; Rodeheffer, D.; Ducrocq, V.; Bousquet, O.; Labatut, L.; Roussot, O.; Farges, T.; Vergeiner, C.; Schulz, W.; Anderson, G.; Pedeboy, S.; Betz, H.; Lagouvardos, K.; Ortega, P.; Molinié, G.; Blanchet, P.
The PEACH (Projet en Electricité Atmosphérique pour la Campagne HyMeX) project is the Atmospheric Electricity component of the HyMeX (Hydrology cycle in the Mediterranean Experiment) experiment aimed at measuring and analyzing the lightning activity and electrical state of thunderstorms over the Mediterranean Sea. During the SOP1 (Special Observation Period; September-October 2012), records of four European operational lightning detection networks (ATDNET, UKMO; EUCLID; LINET, nowcast; ZEUS, NOA) and the NMT Lightning Mapping Array (LMA) were used to locate and characterize the lightning activity over South-Eastern France. Other research instruments such as induction rings (LA), electric field measurements (OVE; LA; NMT), video camera (OVE; ONERA), microbarometer and microphone arrays (CEA) were deployed to document the properties of the lightning flashes as well as the electrical state of parent thunderclouds. All these observations are used to document the evolution of the electrical activity during the life cycle of SOP storms in conjunction with microphysics and kinematics description of the parent storms as derived mainly from ground-based radar and airborne in situ observations. Interpretation of the results are performed with the use of cloud models (MM5; MESO-NH with its electrification and lightning schemes). We will present an overview of the PEACH project. We will discuss some of the recorded cases. We will also introduce some of the products that will be made available to the HyMeX Community.
An Equivalent Electrical Circuit Model of Proton Exchange Membrane Fuel Cells Based on Mathematical Modelling
Directory of Open Access Journals (Sweden)
Dinh An Nguyen
Full Text Available Many of the Proton Exchange Membrane Fuel Cell (PEMFC models proposed in the literature consist of mathematical equations. However, they are not adequately practical for simulating power systems. The proposed model takes into account phenomena such as activation polarization, ohmic polarization, double layer capacitance and mass transport effects present in a PEM fuel cell. Using electrical analogies and a mathematical modeling of PEMFC, the circuit model is established. To evaluate the effectiveness of the circuit model, its static and dynamic performances under load step changes are simulated and compared to the numerical results obtained by solving the mathematical model. Finally, the applicability of our model is demonstrated by simulating a practical system.
Estimation of Operating Condition of Appliances Using Circuit Current Data on Electric Distribution Boards
Iwafune, Yumiko; Ogimoto, Kazuhiko; Yagita, Yoshie
The Energy management systems (EMS) on demand sides are expected as a method to enhance the capability of supply and demand balancing of a power system under the anticipated penetration of renewable energy generation such as Photovoltaics (PV). Elucidation of energy consumption structure in a building is one of important elements for realization of EMS and contributes to the extraction of potential energy saving. In this paper, we propose the estimation method of operating condition of household appliances using circuit current data on an electric distribution board. Circuit current data are broken down by their shape using a self-organization map method and aggregated by appliance based on customers' information of appliance possessed. Proposed method is verified using residential energy consumption measurement survey data.
Experimental study of an adaptive elastic metamaterial controlled by electric circuits
Zhu, R.; Chen, Y. Y.; Barnhart, M. V.; Hu, G. K.; Sun, C. T.; Huang, G. L.
The ability to control elastic wave propagation at a deep subwavelength scale makes locally resonant elastic metamaterials very relevant. A number of abilities have been demonstrated such as frequency filtering, wave guiding, and negative refraction. Unfortunately, few metamaterials develop into practical devices due to their lack of tunability for specific frequencies. With the help of multi-physics numerical modeling, experimental validation of an adaptive elastic metamaterial integrated with shunted piezoelectric patches has been performed in a deep subwavelength scale. The tunable bandgap capacity, as high as 45%, is physically realized by using both hardening and softening shunted circuits. It is also demonstrated that the effective mass density of the metamaterial can be fully tailored by adjusting parameters of the shunted electric circuits. Finally, to illustrate a practical application, transient wave propagation tests of the adaptive metamaterial subjected to impact loads are conducted to validate their tunable wave mitigation abilities in real-time.
Study of switching electric circuits with DC hybrid breaker, one stage
Niculescu, T.; Marcu, M.; Popescu, F. G.
The paper presents a method of extinguishing the electric arc that occurs between the contacts of direct current breakers. The method consists of using an LC type extinguishing group to be optimally sized. From this point of view is presented a theoretical approach to the phenomena that occurs immediately after disconnecting the load and the specific diagrams are drawn. Using these, the elements extinguishing group we can choose. At the second part of the paper there is presented an analyses of the circuit switching process by decomposing the process in particular time sequences. For every time interval there was conceived a numerical simulation model in MATLAB-SIMULINK medium which integrates the characteristic differential equation and plots the capacitor voltage variation diagram and the circuit dumping current diagram.
Factors influencing the renal arterial Doppler waveform: a simulation study using an electrical circuit model (secondary publication
Directory of Open Access Journals (Sweden)
Chang Kyu Sung
Full Text Available Purpose: The goal of this study was to evaluate the effect of vascular compliance, resistance, and pulse rate on the resistive index (RI by using an electrical circuit model to simulate renal blood flow. Methods: In order to analyze the renal arterial Doppler waveform, we modeled the renal blood-flow circuit with an equivalent simple electrical circuit containing resistance, inductance, and capacitance. The relationships among the impedance, resistance, and compliance of the circuit were derived from well-known equations, including Kirchhoff's current law for alternating current circuits. Simulated velocity-time profiles for pulsatile flow were generated using Mathematica (Wolfram Research and the influence of resistance, compliance, and pulse rate on waveforms and the RI was evaluated. Results: Resistance and compliance were found to alter the waveforms independently. The impedance of the circuit increased with increasing proximal compliance, proximal resistance, and distal resistance. The impedance decreased with increasing distal compliance. The RI of the circuit decreased with increasing proximal compliance and resistance. The RI increased with increasing distal compliance and resistance. No positive correlation between impedance and the RI was found. Pulse rate was found to be an extrinsic factor that also influenced the RI. Conclusion: This simulation study using an electrical circuit model led to a better understanding of the renal arterial Doppler waveform and the RI, which may be useful for interpreting Doppler findings in various clinical settings.
Factors influencing the renal arterial Doppler waveform: a simulation study using an electrical circuit model (secondary publication)
Energy Technology Data Exchange (ETDEWEB)
Sung, Chang Kyu [Dept. of Radiology, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, Seoul (Korea, Republic of); Han, Bong Soo [Dept. of Radiological Science, College of Health Science, Yonsei University, Wonju (Korea, Republic of); Kim, Seung Hyup [Dept. of Radiology, Institute of Radiation Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul (Korea, Republic of)
The goal of this study was to evaluate the effect of vascular compliance, resistance, and pulse rate on the resistive index (RI) by using an electrical circuit model to simulate renal blood flow. In order to analyze the renal arterial Doppler waveform, we modeled the renal blood-flow circuit with an equivalent simple electrical circuit containing resistance, inductance, and capacitance. The relationships among the impedance, resistance, and compliance of the circuit were derived from well-known equations, including Kirchhoff's current law for alternating current circuits. Simulated velocity-time profiles for pulsatile flow were generated using Mathematica (Wolfram Research) and the influence of resistance, compliance, and pulse rate on waveforms and the RI was evaluated. Resistance and compliance were found to alter the waveforms independently. The impedance of the circuit increased with increasing proximal compliance, proximal resistance, and distal resistance. The impedance decreased with increasing distal compliance. The RI of the circuit decreased with increasing proximal compliance and resistance. The RI increased with increasing distal compliance and resistance. No positive correlation between impedance and the RI was found. Pulse rate was found to be an extrinsic factor that also influenced the RI. This simulation study using an electrical circuit model led to a better understanding of the renal arterial Doppler waveform and the RI, which may be useful for interpreting Doppler findings in various clinical settings.
Alignment of atmospheric mineral dust due to electric field
Directory of Open Access Journals (Sweden)
Z. Ulanowski
Full Text Available Optical polarimetry observations on La Palma, Canary Islands, during a Saharan dust episode show dichroic extinction consistent with the presence of vertically aligned particles in the atmosphere. Modelling of the extinction together with particle orientation indicates that the alignment could have been due to an electric field of the order of 2 kV/m. Two alternative mechanisms for the origin of the field are examined: the effect of reduced atmospheric conductivity and charging of the dust layer, the latter effect being a more likely candidate. It is concluded that partial alignment may be a common feature of Saharan dust layers. The modelling also indicates that the alignment can significantly alter dust optical depth. This "Venetian blind effect" may have decreased optical thickness in the vertical direction by as much as 10% for the case reported here.
Highly stretchable electric circuits from a composite material of silver nanoparticles and elastomeric fibres.
Park, Minwoo; Im, Jungkyun; Shin, Minkwan; Min, Yuho; Park, Jaeyoon; Cho, Heesook; Park, Soojin; Shim, Mun-Bo; Jeon, Sanghun; Chung, Dae-Young; Bae, Jihyun; Park, Jongjin; Jeong, Unyong; Kim, Kinam
Conductive electrodes and electric circuits that can remain active and electrically stable under large mechanical deformations are highly desirable for applications such as flexible displays, field-effect transistors, energy-related devices, smart clothing and actuators. However, high conductivity and stretchability seem to be mutually exclusive parameters. The most promising solution to this problem has been to use one-dimensional nanostructures such as carbon nanotubes and metal nanowires coated on a stretchable fabric, metal stripes with a wavy geometry, composite elastomers embedding conductive fillers and interpenetrating networks of a liquid metal and rubber. At present, the conductivity values at large strains remain too low to satisfy requirements for practical applications. Moreover, the ability to make arbitrary patterns over large areas is also desirable. Here, we introduce a conductive composite mat of silver nanoparticles and rubber fibres that allows the formation of highly stretchable circuits through a fabrication process that is compatible with any substrate and scalable for large-area applications. A silver nanoparticle precursor is absorbed in electrospun poly (styrene-block-butadiene-block-styrene) (SBS) rubber fibres and then converted into silver nanoparticles directly in the fibre mat. Percolation of the silver nanoparticles inside the fibres leads to a high bulk conductivity, which is preserved at large deformations (σ ≈ 2,200 S cm(-1) at 100% strain for a 150-µm-thick mat). We design electric circuits directly on the electrospun fibre mat by nozzle printing, inkjet printing and spray printing of the precursor solution and fabricate a highly stretchable antenna, a strain sensor and a highly stretchable light-emitting diode as examples of applications.
Development and Implementation of an Electric Circuits On-Line Course
Ahmed Hussain; Umar Johar; Noman Tassaduq; Hussain Al-Jamid; Mahmoud M. Dawoud
An electric circuit on-line course has been developed at KFUPM to support student centered learning. The course has been used in the first stage to supplement the class room face-to-face instruction. This paper describes the development stages of the on-line course and highlights its fundamental features that are not available in the traditional methods of instruction. The paper also includes the results of a survey conducted among students who have utilized the on-line material to supplement...
Electrical circuit models for performance modeling of Lithium-Sulfur batteries
DEFF Research Database (Denmark)
Knap, Vaclav; Stroe, Daniel Ioan; Teodorescu, Remus;
Energy storage technologies such as Lithium-ion (Li-ion) batteries are widely used in the present effort to move towards more ecological solutions in sectors like transportation or renewable-energy integration. However, today's Li-ion batteries are reaching their limits and not all demands...... emerging technology for various applications, there is a need for Li-S battery performance model; however, developing such models represents a challenging task due to batteries' complex ongoing chemical reactions. Therefore, the literature review was performed to summarize electrical circuit models (ECMs...
Atmospheric Electric Field Measurements at 100 Hz and High Frequency Electric Phenomena
Conceição, Ricardo; Gonçalves da Silva, Hugo; Matthews, James; Bennett, Alec; Chubb, John
Spectral response of Atmospheric Electric Potential Gradient (PG), symmetric to the Atmospheric Electric Field, gives important information about phenomena affecting these measurements with characteristic time-scales that appear in the spectra as specific periodicities. This is the case of urban pollution that has a clear weekly dependence and reveals itself on PG measurements by a ~7 day periodicity (Silva et al., 2014). While long-term time-scales (low frequencies) have been exhaustively explored in literature, short-term time-scales (high frequencies), above 1 Hz, have comparatively received much less attention (Anisimov et al., 1999). This is mainly because of the technical difficulties related with the storage of such a huge amount of data (for 100 Hz sampling two days of data uses a ~1 Gb file) and the response degradation of the field-meters at such frequencies. Nevertheless, important Electric Phenomena occurs for frequencies above 1 Hz that are worth pursuing, e.g. the Schumann Resonances have a signature of worldwide thunderstorm activity at frequencies that go from ~8 up to ~40 Hz. To that end the present work shows preliminary results on PG measurements at 100 Hz that took place on two clear-sky days (17th and 18th June 2015) on the South of Portugal, Évora (38.50° N, 7.91° W). The field-mill used is a JCI 131F installed in the University of Évora campus (at 2 m height) with a few trees and two buildings in its surroundings (~50 m away). This device was developed by John Chubb (Chubb, 2014) and manufactured by Chilworth (UK). It was calibrated in December 2013 and recent work by the author (who is honored in this study for his overwhelming contribution to atmospheric electricity) reveals basically a flat spectral response of the device up to frequencies of 100 Hz (Chubb, 2015). This makes this device suitable for the study of High Frequency Electric Phenomena. Anisimov, S.V., et al. (1999). On the generation and evolution of aeroelectric structures
Mode of the short circuit in the direct current electric traction network with different feed charts of fyder area
Directory of Open Access Journals (Sweden)
P. Mihalichenko
Full Text Available In the article the results of mathematical design of the system of electric traction of direct current are represented in the mode of short circuit and different feed charts of fyder area: two-sided; one-sided. Comparison of transitional electric sizes which characterize electromagnetic processes during these malfunctions is analysed and executed.
Simple voltage-controlled current source for wideband electrical bioimpedance spectroscopy: circuit dependences and limitations
International Nuclear Information System (INIS)
In this work, the single Op-Amp with load-in-the-loop topology as a current source is revisited. This circuit topology was already used as a voltage-controlled current source (VCCS) in the 1960s but was left unused when the requirements for higher frequency arose among the applications of electrical bioimpedance (EBI). The aim of the authors is not only limited to show that with the currently available electronic devices it is perfectly viable to use this simple VCCS topology as a working current source for wideband spectroscopy applications of EBI, but also to identify the limitations and the role of each of the circuit components in the most important parameter of a current for wideband applications: the output impedance. The study includes the eventual presence of a stray capacitance and also an original enhancement, driving with current the VCCS. Based on the theoretical analysis and experimental measurements, an accurate model of the output impedance is provided, explaining the role of the main constitutive elements of the circuit in the source's output impedance. Using the topologies presented in this work and the proposed model, any electronic designer can easily implement a simple and efficient current source for wideband EBI spectroscopy applications, e.g. in this study, values above 150 kΩ at 1 MHz have been obtained, which to the knowledge of the authors are the largest values experimentally measured and reported for a current source in EBI at this frequency
Simple voltage-controlled current source for wideband electrical bioimpedance spectroscopy: circuit dependences and limitations
Seoane, F.; Macías, R.; Bragós, R.; Lindecrantz, K.
In this work, the single Op-Amp with load-in-the-loop topology as a current source is revisited. This circuit topology was already used as a voltage-controlled current source (VCCS) in the 1960s but was left unused when the requirements for higher frequency arose among the applications of electrical bioimpedance (EBI). The aim of the authors is not only limited to show that with the currently available electronic devices it is perfectly viable to use this simple VCCS topology as a working current source for wideband spectroscopy applications of EBI, but also to identify the limitations and the role of each of the circuit components in the most important parameter of a current for wideband applications: the output impedance. The study includes the eventual presence of a stray capacitance and also an original enhancement, driving with current the VCCS. Based on the theoretical analysis and experimental measurements, an accurate model of the output impedance is provided, explaining the role of the main constitutive elements of the circuit in the source's output impedance. Using the topologies presented in this work and the proposed model, any electronic designer can easily implement a simple and efficient current source for wideband EBI spectroscopy applications, e.g. in this study, values above 150 kΩ at 1 MHz have been obtained, which to the knowledge of the authors are the largest values experimentally measured and reported for a current source in EBI at this frequency.
Electrical Circuit Modeling Considering a Transient Space Charge for Nonsteady Poisson-Nernst-Planck Equations
Sugioka, Hideyuki
Transient space charge phenomena at high step voltages are interesting since they play a central role in many exotic nonequilibrium phenomena of ion dynamics in an electrolyte. However, the fundamental equations [i.e., the nonsteady Poisson-Nernst-Planck (PNP) equations] have not been solved analytically at high applied voltages because of their large nonlinearity. In this study, on the basis of the steady PNP solution, we propose an electrical circuit model that considers transient space charge effects and find that the dc and ac responses of the total charge of the electrical double layer are in fairly good agreement with the numerical results even at large applied voltages. Furthermore, on the basis of this model, we find approximate analytical solutions for the nonsteady PNP equations that are in good agreement with the numerical solutions of the concentration, charge density, and potential distribution at high applied voltages at each time in a surface region.
A high-speed electrical impedance measurement circuit based on information-filtering demodulation
International Nuclear Information System (INIS)
In the paper, an information-filtering demodulation method is proposed and a high-speed ac-based electrical impedance measurement circuit with a simple configuration is presented. As a crucial part of the ac-based impedance measurement circuit, the information-filtering demodulator can output a preliminary demodulation result by processing only a small number of sampling data within a signal period and the signal-to-noise ratio (SNR) can be further improved by involving more sampling data. Compared with other digital demodulators requiring integer multiples of the signal's period, the information-filtering demodulator is more advantageous in flexibility. Moreover, compared with the recursive least-squares-based demodulator, the proposed demodulator is of relatively low computation complexity and suitable to be implemented on a field programmable gate array. Using this demodulator, the ac impedance measurement circuit based on the ac self-balancing bridge can achieve a high measurement speed. Experimental results showed that one measurement can be accomplished in 17 µs, corresponding to one-third of the signal period, at an excitation frequency of 20 kHz, and the demodulation SNR can reach up to 65 dB. If the data of a complete signal period are used for demodulation like other widely used digital demodulators, the SNR of amplitude demodulation will be higher than 75 dB and the standard deviation of the demodulated phase is below 0.012°, which validates the good performance of both the new demodulator and the impedance measurement circuit. (paper)
Electric Currents and Fields in Middle and Low Atmosphere in Fair-Weather Regions due to Distant Thunderstorms
Velinov, Peter; Velinov, Peter; Tonev, Peter
The electric currents created by the thunderstorms and the electrified shower clouds over the Earth flow into the global atmospheric electric circuit and are responsible for the formation in fair-weather regions of ionosphere-ground current of about 2 pA per square meter, as well as for the related fair-weather electric field of the order of 100 V/m at sea level. The link of the diurnal variations of the fair-weather electric field with the global thunderstorm activity has been widely studied with connection to the Wilson's hypothesis. To confirm this hypothesis directly, also the fair-weather electric field response to a strong single lightning discharge has being examined. Here we study theoretically the variations of the electric currents and fields in fair-weather regions at different altitudes of the lower and middle atmosphere, which are provoked by distant lightning discharges. The electric field variations can play an important role at higher altitudes (in the upper troposphere and above), where they are much larger and possibly influence the physical and chemical processes. For our goals we realize a globalscale model of the electric fields and currents generated by a lightning discharge, which is based on the Maxwell's equations. The fair-weather electric characteristics are studied by our model depending on the lightning parameters, location and distance. We also examine how variations of the conductivity in the strato/mesosphere due to changes of solar and geomagnetic activity affect the characteristics studied. Another question discussed is whether and how the mesospheric electric response to a remote lightning discharge is influenced by the conductivity anisotropy above 70 km and by the geomagnetic field geometry. The variations of the fairweather electric fields due to a distant lightning at tropospheric heights are also studied with respect to their presumable role in the cloud physics.
Combined Aircraft and Satellite-Derived Storm Electric Current and Lightning Rates Measurements and Implications for the Global Electric Circuit
Mach, Douglas M.; Blakeslee, Richard J.; Bateman, Monte G.
Using rotating vane electric field mills and Gerdien capacitors, we measured the electric field profile and conductivity during 850 overflights of electrified shower clouds and thunderstorms spanning regions including the Southeastern United States, the Western Atlantic Ocean, the Gulf of Mexico, Central America and adjacent oceans, Central Brazil, and the South Pacific. The overflights include storms over land and ocean, with and without lightning, and with positive and negative fields above the storms. The measurements were made with the NASA ER-2 and the Altus-II high altitude aircrafts. Peak electric fields, with lightning transients removed, ranged from -1.0 kV/m to 16 kV/m, with a mean value of 0.9 kV/m. The median peak field was 0.29 kV/m. Integrating our electric field and conductivity data, we determined total conduction currents and flash rates for each overpass. With knowledge of the storm location (land or ocean) and type (with or without lightning), we determine the mean currents by location and type. The mean current for ocean storms with lightning is 1.6 A while the mean current for land storms with lightning is 1.0 A. The mean current for oceanic storms without lightning (i.e., electrified shower clouds) is 0.39 A and the mean current for land storms without lightning is 0.13 A. Thus, on average, land storms with or without lightning have about half the mean current as their corresponding oceanic storm counterparts. Over three-quarters (78%) of the land storms had detectable lightning, while less than half (43%) of the oceanic storms had lightning. We did not find any significant regional or latitudinal based patterns in our total conduction currents. By combining the aircraft derived storm currents and flash rates with diurnal lightning statistics derived from the Lightning Imaging Sensor (LIS) and Optical Transient Detector (OTD) low Earth orbiting satellites, we reproduce the diurnal variation in the global electric circuit (i.e., the Carnegie
Electrical conductivity of plasmas of DB white dwarf atmospheres
Sreckovic, V A; Mihajlov, A A; Dimitrijevic, M S; 10.1111/j.1365-2966.2010.16702.x
The static electrical conductivity of non-ideal, dense, partially ionized helium plasma was calculated over a wide range of plasma parameters: temperatures $1\\cdot 10^{4}\\textrm{K} \\lesssim T \\lesssim 1\\cdot 10^{5}\\textrm{K}$ and mass density $1 \\times 10^{-6} \\textrm{g}/\\textrm{cm}^{3} \\lesssim \\rho \\lesssim 2 \\textrm{g}/\\textrm{cm}^{3}$. Calculations of electrical conductivity of plasma for the considered range of plasma parameters are of interest for DB white dwarf atmospheres with effective temperatures $1\\cdot 10^{4}\\textrm{K} \\lesssim T_{eff} \\lesssim 3\\cdot 10^{4}\\textrm{K}$. Electrical conductivity of plasma was calculated by using the modified random phase approximation and semiclassical method, adapted for the case of dense, partially ionized plasma. The results were compared with the unique existing experimental data, including the results related to the region of dense plasmas. In spite of low accuracy of the experimental data, the existing agreement with them indicates that results obtained in th...
An improved electrical and thermal model of a microbolometer for electronic circuit simulation
Würfel, D.; Vogt, H.
The need for uncooled infrared focal plane arrays (IRFPA) for imaging systems has increased since the beginning of the nineties. Examples for the application of IRFPAs are thermography, pedestrian detection for automotives, fire fighting, and infrared spectroscopy. It is very important to have a correct electro-optical model for the simulation of the microbolometer during the development of the readout integrated circuit (ROIC) used for IRFPAs. The microbolometer as the sensing element absorbs infrared radiation which leads to a change of its temperature due to a very good thermal insulation. In conjunction with a high temperature coefficient of resistance (TCR) of the sensing material (typical vanadium oxide or amorphous silicon) this temperature change results in a change of the electrical resistance. During readout, electrical power is dissipated in the microbolometer, which increases the temperature continuously. The standard model for the electro-optical simulation of a microbolometer includes the radiation emitted by an observed blackbody, radiation emitted by the substrate, radiation emitted by the microbolometer itself to the surrounding, a heat loss through the legs which connect the microbolometer electrically and mechanically to the substrate, and the electrical power dissipation during readout of the microbolometer (Wood, 1997). The improved model presented in this paper takes a closer look on additional radiation effects in a real IR camera system, for example the radiation emitted by the casing and the lens. The proposed model will consider that some parts of the radiation that is reflected from the casing and the substrate is also absorbed by the microbolometer. Finally, the proposed model will include that some fraction of the radiation is transmitted through the microbolometer at first and then absorbed after the reflection at the surface of the substrate. Compared to the standard model temperature and resistance of the microbolometer can be
Number-Phase Quantization Scheme and the Quantum Effects of a Mesoscopic Electric Circuit at Finite Temperature
Wang, Shuai
For L-C circuit, a new quantized scheme has been proposed in the context of number-phase quantization. In this quantization scheme, the number n of the electric charge q( q= en) is quantized as the charge number operator and the phase difference θ across the capacity is quantized as phase operator. Based on the scheme of number-phase quantization and the thermo field dynamics (TFD), the quantum fluctuations of the charge number and phase difference of a mesoscopic L-C circuit in the thermal vacuum state, the thermal coherent state and the thermal squeezed state have been studied. It is shown that these quantum fluctuations of the charge number and phase difference are related to not only the parameters of circuit, the squeezing parameter, but also the temperature in these quantum states. It is proven that the number-phase quantization scheme is very useful to tackle with quantization of some mesoscopic electric circuits and the quantum effects.
Three-dimensional Model Analysis of Electric Field Excited by Multi-circuit Intersecting Overhead Transmission Lines
Institute of Scientific and Technical Information of China (English)
XIAO Dongping; LEI Hui; ZHANG Zhanlong; HE Wei
This work is carried out to predict the special distribution of electric field induced by multi-circuit intersecting overhead high-voltage (HV) transmission lines (TLs) within a large range without any expensive and time-consuming computation.The two main parts of the presented methodology are 1) setting up a three-dimensional (3D) model to calculate the electric field based on combining catenary equations with charge simulation method and 2) calculating the hybrid electric field excited by multi-circuit intersecting TLs using coordinate transformation and superposition technique.Examples of different TLs configurations,including a 220 kV single-circuit horizontally configured TLs,a 500 kV single-circuit triangularly configured TLs and a combination of the 220 kV TLs and the 550 kV TLs,are illustrated to verify the validity of this methodology.A more complicatal configurations,including a 500 kV double-circuit TLs and two 220kV single-circuit horizontally configured TLs,are also calculated.Conclusions were drawn from the simulation:1) The presented 3D model outperforms 2D models in describing the electric field distribution generated by practical HV TLs with sag and span.2) Coordinate transformation and superposition technique considerably simplify the electric field computation for multi-circuit TLs configurations,which makes it possible to deal with complex engineering problems.3) The electric field in the area covered by multiple intersecting overhead TLs is distorted and the hybrid electric field strength in some partial region increases so sharply that it might exceed the admissible value.4) The configuration parameters of the TLs and the spatial configuration of multi-circuit TLs,for instance,the height of TLs,the length of span and the intersection angle of multiple circuits,influence the strength and the distribution of hybrid electric field.The influence regularities summarized in this paper can be referred by future TL designs to meet the electromagnetic
Thermosphere and ionosphere response on seismogenic disturbances of the global electric circuit
Karpov, Mikhail; Namgaladze, Aleksandr; Knyazeva, Maria
Conditions of warm, humid and ionized air over the active tectonic faults favor the formation of clouds and generation of the intense vertical electric current between the Earth and ionosphere. The latter arises due to separation and vertical transport of the oppositely charged particles by the gravity force and pressure gradients. Additional transport of charged particles into the ionosphere causes disturbances of the ionosphere plasma (under the action of the electric currents in the E-layer and electromagnetic plasma drift in the F2-layer) and thermosphere neutral gas (via the momentum transfer from electric to neutral particles). The thermosphere and ionosphere variations formed under the action of the electric field created by this vertical electric current have been calculated by using the Upper Atmosphere Model (UAM), and a good agreement was found between observed and the UAM calculated perturbations of the electric field, electron and ion concentrations, total electron content (TEC), ion and electron temperatures as well as wind velocities and neutral gas temeperature and concentrations. The roles of the internal gravity waves and electromagnetic plasma drift in generation of the seismogenic TEC variations are discussed.
Electrical characterization of atmospheric pressure dielectric barrier discharge in air
International Nuclear Information System (INIS)
This paper reports the electrical characterization of dielectric barrier discharge produced at atmospheric pressure using a high voltage power supply operating at 50Hz. The characteristics of the discharge have been studied under different values as such applied voltage and the electrode gap width. The results presented in this work can be helpful in understanding the influence of dielectric material on the nature of the discharge. An attempt has also been made to investigate the influence of ballast resistor on the magnitude of discharge current and also the density of micro-discharges. Our results indicated that with this power supply and electrode geometry, a relatively more homogenous discharge is observed for 3 mm spacing. (author)
An Empirical Model for Estimating the Probability of Electrical Short Circuits from Tin Whiskers-Part I
Courey, Karim; Wright, Clara; Asfour, Shihab; Bayliss, Jon; Ludwig, Larry
Existing risk simulations make the assumption that when a free tin whisker has bridged two adjacent exposed electrical conductors, the result is an electrical short circuit. This conservative assumption is made because shorting is a random event that has a currently unknown probability associated with it. Due to contact resistance, electrical shorts may not occur at lower voltage levels. In this experiment, we study the effect of varying voltage on the breakdown of the contact resistance which leads to a short circuit. From this data, we can estimate the probability of an electrical short, as a function of voltage, given that a free tin whisker has bridged two adjacent exposed electrical conductors. In addition, three tin whiskers grown from the same Space Shuttle Orbiter card guide used in the aforementioned experiment were cross sectioned and studied using a focused ion beam (FIB).
大气机高度输出接口电路的设计%Design of Height Output Interface Circuit for Atmosphere Machine
Institute of Scientific and Technical Information of China (English)
侯民胜; 田宇
为完成俄制大气机与国产航管应答机的交连,设计了由单片机、A/D转换器、电平转换电路、驱动电路、隔离电路和电源等电路组成的俄制大气机高度输出接口板电路.采取数据校准和抗干扰技术,简化硬件电路,提高高度数据转换精度和系统的抗干扰能力.实验表明,该接口电路实现了高度数据的数字化,能够将饿制大气机输出的模拟高度电平信号转换成满足国产航空应答机要求的数字编码信号.%In order to connect Russian-made atmosphere machine with the domestic ATC(Air Traffic Control) , a Russian-made height output interface circuit for atmosphere machine consisted of single chip microcomputer, A/D converter, level converter , driver circuit, isolator and electrical power was designed. The data correlation and anti-jamming technique were adopted to simplify hardware and to enhance conversion precision of height data and anti-jamming performance of the system. The test shows that the interface circuit can convert the analog height signal to digital encoding signal which is fit for the requirements of domestic ATC transponder.
Cold atmospheric plasma jet in an axial DC electric field
Lin, Li; Keidar, Michael
Cold atmospheric plasma (CAP) jet is currently intensively investigated as a tool for new and potentially transformative cancer treatment modality. However, there are still many unknowns about the jet behavior that requires attention. In this paper, a helium CAP jet is tested in an electrostatic field generated by a copper ring. Using Rayleigh microwave scattering method, some delays of the electron density peaks for different ring potentials are observed. Meanwhile, a similar phenomenon associated with the bullet velocity is found. Chemical species distribution along the jet is analyzed based on the jet optical emission spectra. The spectra indicate that a lower ring potential, i.e., lower DC background electric field, can increase the amount of excited N2, N2+, He, and O in the region before the ring, but can decrease the amount of excited NO and HO almost along the entire jet. Combining all the results above, we discovered that an extra DC potential mainly affects the temporal plasma jet properties. Also, it is possible to manipulate the chemical compositions of the jet using a ring with certain electric potentials.
Circuit modeling of the electrical impedance: part III. Disuse following bone fracture
International Nuclear Information System (INIS)
Multifrequency measurements of the electrical impedance of muscle have been extended to the study of disuse following bone fracture, and analyzed using the five-element circuit model used earlier in the study of the effects of disease. Eighteen subjects recovering from simple fractures on upper or lower limbs were examined (ten males, eight females, aged 18–66). Muscles on uninjured contralateral limbs were used as comparison standards, and results are presented in terms of the ratios p(injured)/p(uninjured), where p stands for the circuit parameter r1, r2, r3, 1/c1 or 1/c2. These are strikingly similar to the diseased-to-healthy ratios for patients with neuromuscular disease, reported in part I of this series. In particular, r1 is virtually unaffected and the ratios for r2, r3, 1/c1 and 1/c2 can be as large as in serious disease. Furthermore, the same pattern of relationships between the parameters is found, suggesting that there is a common underlying mechanism for the impedance changes. Atrophy and fibrosis are examined as candidates for that mechanism, but it is argued that their effects are too small to explain the observed changes. Fundamental considerations aside, the sensitivity, reproducibility and technical simplicity of the technique recommend its use for in-flight assessments of muscles during orbital or interplanetary missions. (paper)
Circuit modeling of the electrical impedance: II. Normal subjects and system reproducibility
International Nuclear Information System (INIS)
Part I of this series showed that the five-element circuit model accurately mimics impedances measured using multi-frequency electrical impedance myography (MFEIM), focusing on changes brought on by disease. This paper addresses two requirements which must be met if the method is to qualify for clinical use. First, the extracted parameters must be reproducible over long time periods such as those involved in the treatment of muscular disease, and second, differences amongst normal subjects should be attributable to known differences in the properties of healthy muscle. It applies the method to five muscle groups in 62 healthy subjects, closely following the procedure used earlier for the diseased subjects. Test–retest comparisons show that parameters are reproducible at levels from 6 to 16% (depending on the parameter) over time spans of up to 267 days, levels far below the changes occurring in serious disease. Also, variations with age, gender and muscle location are found to be consistent with established expectations for healthy muscle tissue. We conclude that the combination of MFEIM measurements and five-element circuit analysis genuinely reflects properties of muscle and is reliable enough to recommend its use in following neuromuscular disease. (paper)
A time-resolved imaging and electrical study on a high current atmospheric pressure spark discharge
Palomares, J. M.; Kohut, A.; Galbács, G.; Engeln, R.; Geretovszky, Zs.
We present a time-resolved imaging and electrical study of an atmospheric pressure spark discharge. The conditions of the present study are those used for nanoparticle generation in spark discharge generator setups. The oscillatory bipolar spark discharge was generated between two identical Cu electrodes in different configurations (cylindrical flat-end or tipped-end geometries, electrode gap from 0.5 to 4 mm), in a controlled co-axial N2 flow, and was supplied by a high voltage capacitor. Imaging data with nanosecond time resolution were collected using an intensified CCD camera. This data were used to study the time evolution of plasma morphology, total light emission intensity, and the rate of plasma expansion. High voltage and high current probes were employed to collect electrical data about the discharge. The electrical data recorded allowed, among others, the calculation of the equivalent resistance and inductance of the circuit, estimations for the energy dissipated in the spark gap. By combining imaging and electrical data, observations could be made about the correlation of the evolution of total emitted light and the dissipated power. It was also observed that the distribution of light emission of the plasma in the spark gap is uneven, as it exhibits a "hot spot" with an oscillating position in the axial direction, in correlation with the high voltage waveform. The initial expansion rate of the cylindrical plasma front was found to be supersonic; thus, the discharge releases a strong shockwave. Finally, the results on equivalent resistance and channel expansion are comparable to those of unipolar arcs. This shows the spark discharge has a similar behavior to the arc regime during the conductive phase and until the current oscillations stop.
Quantifying Demyelination in NK venom treated nerve using its electric circuit model.
Das, H K; Das, D; Doley, R; Sahu, P P
Reduction of myelin in peripheral nerve causes critical demyelinating diseases such as chronic inflammatory demyelinating polyneuropathy, Guillain-Barre syndrome, etc. Clinical monitoring of these diseases requires rapid and non-invasive quantification of demyelination. Here we have developed formulation of nerve conduction velocity (NCV) in terms of demyelination considering electric circuit model of a nerve having bundle of axons for its quantification from NCV measurements. This approach has been validated and demonstrated with toad nerve model treated with crude Naja kaouthia (NK) venom and also shows the effect of Phospholipase A2 and three finger neurotoxin from NK-venom on peripheral nerve. This opens future scope for non-invasive clinical measurement of demyelination. PMID:26932543
Rocket measurements within a polar cap arc - Plasma, particle, and electric circuit parameters
Weber, E. J.; Ballenthin, J. O.; Basu, S.; Carlson, H. C.; Hardy, D. A.; Maynard, N. C.; Kelley, M. C.; Fleischman, J. R.; Pfaff, R. F.
Results are presented from the Polar Ionospheric Irregularities Experiment (PIIE), conducted from Sondrestrom, Greenland, on March 15, 1985, designed for an investigation of processes which lead to the generation of small-scale (less than 1 km) ionospheric irregularities within polar-cap F-layer auroras. An instrumented rocket was launched into a polar cap F layer aurora to measure energetic electron flux, plasma, and electric circuit parameters of a sun-aligned arc, coordinated with simultaneous measurements from the Sondrestrom incoherent scatter radar and the AFGL Airborne Ionospheric Observatory. Results indicated the existence of two different generation mechanisms on the dawnside and duskside of the arc. On the duskside, parameters are suggestive of an interchange process, while on the dawnside, fluctuation parameters are consistent with a velocity shear instability.
Quantifying Demyelination in NK venom treated nerve using its electric circuit model
Das, H. K.; Das, D.; Doley, R.; Sahu, P. P.
Reduction of myelin in peripheral nerve causes critical demyelinating diseases such as chronic inflammatory demyelinating polyneuropathy, Guillain-Barre syndrome, etc. Clinical monitoring of these diseases requires rapid and non-invasive quantification of demyelination. Here we have developed formulation of nerve conduction velocity (NCV) in terms of demyelination considering electric circuit model of a nerve having bundle of axons for its quantification from NCV measurements. This approach has been validated and demonstrated with toad nerve model treated with crude Naja kaouthia (NK) venom and also shows the effect of Phospholipase A2 and three finger neurotoxin from NK-venom on peripheral nerve. This opens future scope for non-invasive clinical measurement of demyelination.
Strategy Levels for Guiding Discussion to Promote Explanatory Model Construction in Circuit Electricity
Williams, E. Grant; Clement, John J.
A framework for describing and tracking the whole-class discussion-based teaching strategies used by a teacher to support students' construction and development of explanatory models for concepts in circuit electricity is described. A new type of diagram developed to portray teacher-student discourse patterns facilitated the identification of two distinct types, or levels, of teaching strategies: 1) those that support dialogical or conversational elements of classroom interaction; and 2) those that support cognitive model construction processes. The latter include the higher-level goals of promoting a cycle of Observation, model Generation, model Evaluation, and model Modification. While previous studies have focused primarily on the dialogical strategies that are essential for fostering communication as an enabling condition, the cognitive strategies identified herein are aimed at fostering conceptual model construction.
Investigating the role of model-based reasoning while troubleshooting an electric circuit
Dounas-Frazer, Dimitri R.; Van De Bogart, Kevin L.; Stetzer, MacKenzie R.; Lewandowski, H. J.
We explore the overlap of two nationally recognized learning outcomes for physics lab courses, namely, the ability to model experimental systems and the ability to troubleshoot a malfunctioning apparatus. Modeling and troubleshooting are both nonlinear, recursive processes that involve using models to inform revisions to an apparatus. To probe the overlap of modeling and troubleshooting, we collected audiovisual data from think-aloud activities in which eight pairs of students from two institutions attempted to diagnose and repair a malfunctioning electrical circuit. We characterize the cognitive tasks and model-based reasoning that students employed during this activity. In doing so, we demonstrate that troubleshooting engages students in the core scientific practice of modeling.
Investigating the role of model-based reasoning while troubleshooting an electric circuit
Dounas-Frazer, Dimitri R; Stetzer, MacKenzie R; Lewandowski, H J
We explore the overlap of two nationally-recognized learning outcomes for physics lab courses, namely, the ability to model experimental systems and the ability to troubleshoot a malfunctioning apparatus. Modeling and troubleshooting are both nonlinear, recursive processes that involve using models to inform revisions to an apparatus. To probe the overlap of modeling and troubleshooting, we collected audiovisual data from think-aloud activities in which eight pairs of students from two institutions attempted to diagnose and repair a malfunctioning electrical circuit. We characterize the cognitive tasks and model-based reasoning that students employed during this activity. In doing so, we demonstrate that troubleshooting engages students in the core scientific practice of modeling.
Memory Elements: A Paradigm Shift in Lagrangian Modeling of Electrical Circuits
Jeltsema, Dimitri
Meminductors and memcapacitors do not allow a Lagrangian formulation in the classical sense since these elements are nonconservative in nature and the associated energies are not state functions. To circumvent this problem, a different configuration space is considered that, instead of the usual loop charges, consist of time-integrated loop charges. As a result, the corresponding Euler-Lagrange equations provide a set of integrated Kirchhoff voltage laws in terms of the element fluxes. Memristive losses can be included via a second scalar function that has the dimension of action. A dual variational principle follows by considering variations of the integrated node fluxes and yields a set of integrated Kirchhoff current laws in terms of the element charges. Although time-integrated charge is a somewhat unusual quantity in circuit theory, it may be considered as the electrical analogue of a mechanical quantity called absement. Based on this analogy, simple mechanical devices are presented that can serve as did...
Estimation of reactive fluxes in gradient stochastic systems using an analogy with electric circuits
Energy Technology Data Exchange (ETDEWEB)
Cameron, M.K., E-mail: firstname.lastname@example.com
Highlights: •The MaxFlux functional should be called the resistivity functional. •A Hamilton–Jacobi approach for computing transition paths in collective variables. •Conversion of the network of reactive channels into an electric circuit. •Test on the Alanine-Dipeptide. Perfect agreement. •Application to the problem of CO escape from Myoglobin. -- Abstract: We propose an approach for finding dominant reactive channels and calculating percentages of reactive flux through each channel in chemical systems driven by a deterministic potential force and a small thermal noise. We assume that the temperature is low enough so that the reactive flux focuses around a finite number of paths connecting the reactant and the product states. These paths can be found in a systematic way by solving a Hamilton–Jacobi equation for the so called MaxFlux functional. We argue that the name "MaxFlux" is misleading: it should be called the resistivity functional instead. Once the network of transition paths is found, one can define an equivalent electric circuit and find the currents through each of its wires. These currents give estimates of the reactive flux along the corresponding transition paths. We test our approach on the problem of finding transition paths in the Alanine-Dipeptide with two dihedral angles where the reactive current can be computed exactly. The percentages of the reactive flux through each reactive channel given by our approach turn out to be in remarkable agreement with the exact ones. We apply this approach to the problem of finding escape paths of a CO molecule from a Myoglobin protein. We find a collection of exit locations and establish percentages of the reactive flux through each of them.
Developing an Empirical Model for Estimating the Probability of Electrical Short Circuits from Tin Whiskers. Part 2
Courey, Karim J.; Asfour, Shihab S.; Onar, Arzu; Bayliss, Jon A.; Ludwig, Larry L.; Wright, Maria C.
To comply with lead-free legislation, many manufacturers have converted from tin-lead to pure tin finishes of electronic components. However, pure tin finishes have a greater propensity to grow tin whiskers than tin-lead finishes. Since tin whiskers present an electrical short circuit hazard in electronic components, simulations have been developed to quantify the risk of said short circuits occurring. Existing risk simulations make the assumption that when a free tin whisker has bridged two adjacent exposed electrical conductors, the result is an electrical short circuit. This conservative assumption is made because shorting is a random event that had an unknown probability associated with it. Note however that due to contact resistance electrical shorts may not occur at lower voltage levels. In our first article we developed an empirical probability model for tin whisker shorting. In this paper, we develop a more comprehensive empirical model using a refined experiment with a larger sample size, in which we studied the effect of varying voltage on the breakdown of the contact resistance which leads to a short circuit. From the resulting data we estimated the probability distribution of an electrical short, as a function of voltage. In addition, the unexpected polycrystalline structure seen in the focused ion beam (FIB) cross section in the first experiment was confirmed in this experiment using transmission electron microscopy (TEM). The FIB was also used to cross section two card guides to facilitate the measurement of the grain size of each card guide's tin plating to determine its finish.
Atmospheric Electricity Effects of Eastern Mediterranean Dust Storms
Katz, Shai; Yair, Yoav; Yaniv, Roy; Price, Colin
We present atmospheric electrical measurements conducted at the Wise Observatory (WO) in Mizpe-Ramon (30035'N, 34045'E) and Mt. Hermon (30024'N, 35051'E), Israel, during two massive and unique dust storms that occurred over the Eastern Mediterranean region on February 10-11 and September 08-12, 2015. The first event transported Saharan dust from Egypt and the Sinai Peninsula in advance of a warm front of a Cyprus low pressure system. In the second event, dust particles were transported from the Syrian desert, which dominates the north-east border with Iraq, through flow associated with a shallow Persian trough system. In both events the concentrations of PM10 particles measured by the air-quality monitoring network of the Israeli Ministry of the Environment in Beer-Sheba reached values > 2200 μg m-3. Aerosol Optical Thickness (AOT) obtained from the AERONET station in Sde-Boker reached values up to 4.0. The gradual intensification of the first event reached peak values on the February 11th > 1200 μg m-3 and an AOT ~ 1.8, while the second dust storm commenced on September 8th with a sharp increase reaching peak values of 2225 μg m-3 and AOT of 4.0. Measurements of the fair weather vertical electric field (Ez) and of the vertical current density (Jz) were conducted continuously with a 1 minute temporal resolution. During the February event, very large fluctuations in the electrical parameters were measured at the WO. The Ez values changed between +1000 and +8000 V m-1 while the Jz fluctuated between -10 and +20 pA m-2 (this is an order of magnitude larger compared to the fair weather current density of ~2 pA m-2. In contrast, during the September event, Ez values registered at WO were between -430 and +10 V m-1 while the Jz fluctuated between -6 and +3 pA m2. For the September event the Hermon site showed Ez and Jz values fluctuating between -460 and +570 V m-1 and -14.5 and +18 pA m-2 respectively. The electric field and current variability, amplitude and the
Analogy for Drude's free electron model to promote students' understanding of electric circuits in lower secondary school
de Almeida, Maria José BM; Salvador, Andreia; Costa, Maria Margarida RR
Aiming at a deep understanding of some basic concepts of electric circuits in lower secondary schools, this work introduces an analogy between the behavior of children playing in a school yard with a central lake, subject to different conditions, rules, and stimuli, and Drude's free electron model of metals. Using this analogy from the first school contacts with electric phenomena, one can promote students' understanding of concepts such as electric current, the role of generators, potential difference effects, energy transfer, open and closed circuits, resistances, and their combinations in series and parallel. One believes that through this analogy well-known previous misconceptions of young students about electric circuit behaviors can be overcome. Furthermore, students' understanding will enable them to predict, and justify with self-constructed arguments, the behavior of different elementary circuits. The students' predictions can be verified—as a challenge of self-produced understanding schemes—using laboratory experiments. At a preliminary stage, our previsions were confirmed through a pilot study with three classrooms of 9th level Portuguese students.
Comparing and Combining Real and Virtual Experimentation: An Effort to Enhance Students' Conceptual Understanding of Electric Circuits
Zacharia, Z. C.
The purpose of this study was to investigate value of combining Real Experimentation (RE) with Virtual Experimentation (VE) with respect to changes in students' conceptual understanding of electric circuits. To achieve this, a pre-post comparison study design was used that involved 88 undergraduate students. The participants were randomly assigned…
Self-Regulated Learning Strategies of Engineering College Students While Learning Electric Circuit Concepts with Enhanced Guided Notes
Lawanto, Oenardi; Santoso, Harry
The current study evaluated engineering college students' self-regulated learning (SRL) strategies while learning electric circuit concepts using enhanced guided notes (EGN). Our goal was to describe how students exercise SRL strategies and how their grade performance changes after using EGN. Two research questions guided the study: (1) To what…
Using a Conflict Map as an Instructional Tool To Change Student Conceptions in Simple Series Electric-Circuits.
Tsai, Chin-Chung
Examines the effects of using a conflict map on 8th grade students' conceptual change and ideational networks about simple series electric circuits. Analyzes student interview data through a flow map method. Shows that the use of conflict maps could help students construct greater, richer, and more integrated ideational networks about electric…
To Compare the Effects of Computer Based Learning and the Laboratory Based Learning on Students' Achievement Regarding Electric Circuits
Bayrak, Bekir; Kanli, Uygar; Ingec, Sebnem Kandil
In this study, the research problem was: "Is the computer based physics instruction as effective as laboratory intensive physics instruction with regards to academic success on electric circuits 9th grade students?" For this research of experimental quality the design of pre-test and post-test are applied with an experiment and a control group.…
A Comparison of Students' Conceptual Understanding of Electric Circuits in Simulation Only and Simulation-Laboratory Contexts
Jaakkola, Tomi; Nurmi, Sami; Veermans, Koen
The aim of this experimental study was to compare learning outcomes of students using a simulation alone (simulation environment) with outcomes of those using a simulation in parallel with real circuits (combination environment) in the domain of electricity, and to explore how learning outcomes in these environments are mediated by implicit (only…
A rocket-borne electric field meter for the middle atmosphere
Dettro, G. J.; Smith, L. G.
The design and construction of a rocket-borne electric field meter for determining the atmosphere's electric field and the conductivity in the middle atmosphere are considered. The operating characteristics of the instrument are discussed and a proposed flight configuration is given. The testing of the prototype is described and suggestions are advanced for further improvements.
An improved rocket-borne electric field meter for the middle atmosphere
Burton, D. L.; Smith, L. G.
Improvements in a rocketborne electric field meter designed to measure the atmosphere's electric field and conductivity in the middle atmosphere are described. The general background of the experiment is given as well as changes in the instrument and data processing schemes. Calibration and testing procedures are documented together with suggestions for future work.
Response of the Fair Weather Atmospheric Electrical Current to Geomagnetic Storms
Yair, Yoav; Price, Colin; Elhalal, Gal
The Global Electric Circuit (GEC) is a conceptual model that integrates the observed electrical properties of the atmosphere in the Earth-ionosphere cavity. An average potential difference of 250 kV exists between these two conducting layers, leading to a surface electric field (Ez, sometimes also named the Potential Gradient or PG) of ~130 V/m, and a nearly constant downward flowing direct current density (Jz) of ~2 pA m-2. This is known as the DC component of the GEC. The Jz is an extremely sensitive parameter whose magnitude and fluctuations can be used for monitoring local and global conductivity changes due to aerosols, air-pollution and solar activity. The AC part of the circuit is driven by ~50 lightning flashes per second generating the global Schumann resonances (SR) in the ELF range. There are two time-scales for identifying solar effects on the GEC. On the longer scale, an 11-year modulation by solar activity, likely due to changes in ionization, was reported by several authors. For example, Satori et al. (2005) noted a decrease in the frequency of the first 3 modes of the SR band in conjunction with the solar minimum of 1995-6. On shorter time scales typical of solar activity (e.g. CMEs, solar flares and SEP events), observations show marked perturbations in Jz and in the ionospheric potential at the surface. Cobb (1967) observed an increase of Jz by 75% for ~ 6 h in measurements made at Mauna Loa in Hawaii, during a period of multiple solar flares. Reiter (1989) observed an increase in Jz of about 50%-60% following large solar flares, persisting for 4 days (at the Zungspietze station in the Alps). Belova et al. (2001) reported increased Jz for about 2 hours before T=0 (time of minimum in Bx) as well as enhanced average fluctuations. This talk will review the effects of solar storms on the GEC, and present new results from continuous measurements of Jz conducted at the Wise Observatory in Mitzpe-Ramon, Israel (30°35'N, 34°45'E). During 3 different
Santiago, John
Circuits overloaded from electric circuit analysis? Many universities require that students pursuing a degree in electrical or computer engineering take an Electric Circuit Analysis course to determine who will ""make the cut"" and continue in the degree program. Circuit Analysis For Dummies will help these students to better understand electric circuit analysis by presenting the information in an effective and straightforward manner. Circuit Analysis For Dummies gives you clear-cut information about the topics covered in an electric circuit analysis courses to help
Module Twelve: Series AC Resistive-Reactive Circuits; Basic Electricity and Electronics Individualized Learning System.
Bureau of Naval Personnel, Washington, DC.
The module covers series circuits which contain both resistive and reactive components and methods of solving these circuits for current, voltage, impedance, and phase angle. The module is divided into six lessons: voltage and impedance in AC (alternating current) series circuits, vector computations, rectangular and polar notation, variational…
The characteristic electric impedance of the circuits and its influences in the transient currents; A impedancia caracteristica dos circuitos e sua influencia nas correntes transitorias
Energy Technology Data Exchange (ETDEWEB)
Kascher, Ronaldo [Tesla Projetos e Consultoria Ltda. (Brazil)
Usually not considered in the calculation of the maximum bearable current or even in the voltage drop throughout the electric circuits, the characteristic electric impedance assumes considerable relevance, especially concerning long distance electric power transmission lines. When dimensioning the protection devices, the consideration of the characteristic electric impedance may drastically reduce the necessary investments. 20 figs., 2 tabs.
Application of physical electric circuit modeling to characterize Li-ion battery electrochemical processes
Greenleaf, M.; Li, H.; Zheng, J. P.
A physical electric circuit model (PECM) was used to identify several electrochemical processes occurring in two commercial Li-ion batteries of different cathode materials (LixFePO4 and LixCoO2) via electrochemical impedance spectroscopy (EIS). Through defining these electrochemical processes in these two cells, it was determined that the charge transfer resistance (or exchange current density) observed via EIS was due to the cathodic exchange current densities in both the LixFePO4 and LixCoO2 full cells. In discussing the ionic diffusion of the examined cells, the anode of one cell and the cathode of the other were primarily responsible for the observed diffusion of the full cells. Lastly, the measured double layer capacitance was determined to be represented in EIS scans by the anodes of both full cells. The diffusion coefficient was calculated using Fick's1st Law estimation, and from this coefficient, the particle size was calculated and evaluated against scanning electron microscopy (SEM).
Constructional details for A simple atmospheric electrical instrument for educational use
Bennett, A J
Electricity in the atmosphere provides an ideal topic for educational outreach in environmental science. To support this objective, a simple instrument to measure real atmospheric electrical parameters has been developed and its performance evaluated. This project compliments educational activities undertaken by the Coupling of Atmospheric Layers (CAL) European research collaboration. The new instrument is inexpensive to construct and simple to operate, readily allowing it to be used in schools as well as at the undergraduate University level. It is suited to students at a variety of different educational levels, as the results can be analysed with different levels of sophistication. Students can make measurements of the fair weather electric field and current density, thereby gaining an understanding of the electrical nature of the atmosphere. This work was stimulated by the centenary of the 1906 paper in which C.T.R. Wilson described a new apparatus to measure the electric field and conduction current densi...
An investigation of the effect of instruction in physics on the formation of mental models for problem-solving in the context of simple electric circuits
Beh, Kian Lim
This study was designed to explore the effect of a typical traditional method of instruction in physics on the formation of useful mental models among college students for problem-solving using simple electric circuits as a context. The study was also aimed at providing a comprehensive description of the understanding regarding electric circuits among novices and experts. In order to achieve these objectives, the following two research approaches were employed: (1) A students survey to collect data from 268 physics students; and (2) An interview protocol to collect data from 23 physics students and 24 experts (including 10 electrical engineering graduates, 4 practicing electrical engineers, 2 secondary school physics teachers, 8 physics lecturers, and 4 electrical engineers). Among the major findings are: (1) Most students do not possess accurate models of simple electric circuits as presented implicitly in physics textbooks; (2) Most students display good procedural understanding for solving simple problems concerning electric circuits but have no in-depth conceptual understanding in terms of practical knowledge of current, voltage, resistance, and circuit connections; (3) Most students encounter difficulty in discerning parallel connections that are drawn in a non-conventional format; (4) After a year of college physics, students show significant improvement in areas, including practical knowledge of current and voltage, ability to compute effective resistance and capacitance, ability to identify circuit connections, and ability to solve problems; however, no significance was found in practical knowledge of resistance and ability to connect circuits; and (5) The differences and similarities between the physics students and the experts include: (a) Novices perceive parallel circuits more in terms of 'branch', 'current', and 'resistors with the same resistance' while experts perceive parallel circuits more in terms of 'node', 'voltage', and 'less resistance'; and
Influence of atmospheric electric fields on the radio emission from extensive air showers
Trinh, T. N. G.; Scholten, O.; Buitink, S.; van den Berg, A. M.; Corstanje, A.; Ebert, U.; Enriquez, J. E.; Falcke, H.; Hörandel, J. R.; Köhn, C.; Nelles, A.; Rachen, J. P.; Rossetto, L.; Rutjes, C.; Schellart, P.; Thoudam, S.; ter Veen, S.; de Vries, K. D.
The atmospheric electric fields in thunderclouds have been shown to significantly modify the intensity and polarization patterns of the radio footprint of cosmic-ray-induced extensive air showers. Simulations indicated a very nonlinear dependence of the signal strength in the frequency window of 30-80 MHz on the magnitude of the atmospheric electric field. In this work we present an explanation of this dependence based on Monte Carlo simulations, supported by arguments based on electron dynamics in air showers and expressed in terms of a simplified model. We show that by extending the frequency window to lower frequencies, additional sensitivity to the atmospheric electric field is obtained.
Influence of Atmospheric Electric Fields on the Radio Emission from Extensive Air Showers
Trinh, T N G; Buitink, S; Berg, A M van den; Corstanje, A; Ebert, U; Enriquez, J E; Falcke, H; Hörandel, J R; Köhn, C; Nelles, A; Rachen, J P; Rossetto, L; Rutjes, C; Schellart, P; Thoudam, S; ter Veen, S; de Vries, K D
The atmospheric electric fields in thunderclouds have been shown to significantly modify the intensity and polarization patterns of the radio footprint of cosmic-ray-induced extensive air showers. Simulations indicated a very non-linear dependence of the signal strength in the frequency window of 30-80 MHz on the magnitude of the atmospheric electric field. In this work we present an explanation of this dependence based on Monte-Carlo simulations, supported by arguments based on electron dynamics in air showers and expressed in terms of a simplified model. We show that by extending the frequency window to lower frequencies additional sensitivity to the atmospheric electric field is obtained.
Acquiring Knowledge in Learning Concepts from Electrical Circuits: The Use of Multiple Representations in Technology-Based Learning Environments
Directory of Open Access Journals (Sweden)
Abdeljalil Métioui
Full Text Available The constructivists approach on the conception of relative software of modelling to training and teaching of the concepts of current and voltage requires appraisal of several disciplinary fields in order to provide to the learners a training adapted to their representations. Thus, this approach requires the researchers to have adequate knowledge or skills in data processing, didactics and science content. In this regard, several researches underline that the acquisition of basic concepts that span a field of a given knowledge, must take into account the student and the scientific representations. The present research appears in this perspective, and aims to present the interactive computer environments that take into account the students (secondary and college and scientific representations related to simple electric circuits. These computer environments will help the students to analyze the functions of the electric circuits adequately.
Electrical safety in flammable gas/vapor laden atmospheres
Korver, WOE
This book provides comprehensive coverage of electrical system installation within areas where flammable gases and liquids are handled and processed. The accurate hazard evaluation of flammability risks associated with chemical and petrochemical locations is critical in determining the point at which the costs of electrical equipment and installation are balanced with explosion safety requirements. The book offers the most current code requirements along with tables and illustrations as analytic tools. Environmental characteristics are covered in Section 1 along with recommended electrical ins
A Coupled Dynamical Model of Redox Flow Battery Based on Chemical Reaction, Fluid Flow, and Electrical Circuit
Li, Minghua; Hikihara, Takashi
The redox (Reduction-Oxidation) flow battery is one of the most promising rechargeable batteries due to its ability to average loads and output of power sources. The transient characteristics are well known as the remarkable feature of the battery. Then it can also compensate for a sudden voltage drop. The dynamics are governed by the chemical reactions, fluid flow, and electrical circuit of its structure. This causes the difficulty of the analysis at transient state. This paper discusses the...
Quantum Fluctuation in Mesoscopic Coupled LC Electric Circuits at FiniteTemperature
Institute of Scientific and Technical Information of China (English)
LIANG Xian-Ting; FAN Hong-Yi
We consider the quantization of two coupled LC circuits with mutual inductance at a finite temperature T. It is shown that the quantum mechanical zero-point fluctuations of currents in the two circuits both increase with upgoing T. Thermal field dynamics and Weyl-Wigner theorern are used in our calculation of ensemble average of the observables.
Quantum Fluctuation in Thermal Vacuum State for Mesoscopic LC Electric Circuit
Institute of Scientific and Technical Information of China (English)
FAN Hong-Yi; LIANG Xian-Ting
We consider the quantization of LC (inductance-capacitance) circuit at a finite temperature T as any practical circuits always produce Joule heat except for superconductivity. It is shown that the quantum mechanical zeropoint fluctuations of both charge and current increase with upgoing T. Thermal field dynamics is used in ourdiscussion.
Disassembly and physical separation of electric/electronic components layered in printed circuit boards (PCB).
Lee, Jaeryeong; Kim, Youngjin; Lee, Jae-chun
Although printed circuit boards (PCBs) contain various elements, only the major elements (i.e., those with content levels in wt% or over grade) of and precious metals (e.g., Ag, Au, and platinum groups) contained within PCBs can be recycled. To recover other elements from PCBs, the PCBs should be properly disassembled as the first step of the recycling process. The recovery of these other elements would be beneficial for efforts to conserve scarce resources, reuse electric/electronic components (EECs), and eliminate environmental problems. This paper examines the disassembly of EECs from wasted PCBs (WPCBs) and the physical separation of these EECs using a self-designed disassembling apparatus and a 3-step separation process of sieving, magnetic separation, and dense medium separation. The disassembling efficiencies were evaluated by using the ratio of grinding area (E(area)) and the weight ratio of the detached EECs (E(weight)). In the disassembly treatment, these efficiencies were improved with an increase of grinder speed and grinder height. 97.7% (E(area)) and 98% (E(weight)) could be accomplished ultimately by 3 repetitive treatments at a grinder speed of 5500 rpm and a grinder height of 1.5mm. Through a series of physical separations, most groups of the EECs (except for the diode, transistor, and IC chip groups) could be sorted at a relatively high separation efficiency of about 75% or more. To evaluate the separation efficiency with regard to the elemental composition, the distribution ratio (R(dis)) and the concentration ratio (R(conc)) were used. 15 elements could be separated with the highest R(dis) and R(conc) in the same separated division. This result implies that the recyclability of the elements is highly feasible, even though the initial content in EECs is lower than several tens of mg/kg.
Coupled mechanical-electrical-thermal modeling for short-circuit prediction in a lithium-ion cell under mechanical abuse
Zhang, Chao; Santhanagopalan, Shriram; Sprague, Michael A.; Pesaran, Ahmad A.
In order to better understand the behavior of lithium-ion batteries under mechanical abuse, a coupled modeling methodology encompassing the mechanical, electrical and thermal response is presented for predicting short-circuit under external crush. The combined mechanical-electrical-thermal response is simulated in a commercial finite element software LS-DYNA® using a representative-sandwich finite-element model, where electrical-thermal modeling is conducted after an instantaneous mechanical crush. The model includes an explicit representation of each individual component such as the active material, current collector, separator, etc., and predicts their mechanical deformation under quasi-static indentation. Model predictions show good agreement with experiments: the fracture of the battery structure under an indentation test is accurately predicted. The electrical-thermal simulation predicts the current density and temperature distribution in a reasonable manner. Whereas previously reported models consider the mechanical response exclusively, we use the electrical contact between active materials following the failure of the separator as a criterion for short-circuit. These results are used to build a lumped representative sandwich model that is computationally efficient and captures behavior at the cell level without resolving the individual layers.
The role of the atmospheric electric field in the dust-lifting process
Esposito, F.; Molinaro, R.; Popa, C. I.; Molfese, C.; Cozzolino, F.; Marty, L.; Taj-Eddine, K.; Di Achille, G.; Franzese, G.; Silvestro, S.; Ori, G. G.
Mineral dust particles represent the most abundant component of atmospheric aerosol in terms of dry mass. They play a key role in climate and climate change, so the study of their emission processes is of utmost importance. Measurements of dust emission into the atmosphere are scarce, so that the dust load is generally estimated using models. It is known that the emission process can generate strong atmospheric electric fields. Starting from the data we acquired in the Sahara desert, here, we show for the first time that depending on the relative humidity conditions, electric fields contribute to increase up to a factor of 10 the amount of particles emitted into the atmosphere. This means that electrical forces and humidity are critical quantities in the dust emission process and should be taken into account in climate and circulation models to obtain more realistic estimations of the dust load in the atmosphere.
Disassembly and physical separation of electric/electronic components layered in printed circuit boards (PCB)
International Nuclear Information System (INIS)
Highlights: ► The disassembly of electric/electronic components (EECs) layered in PCB as the first-step in recycling process. ► The disassembling treatment was carried out by the new designed apparatus. ► Most of the EECs (over 95%) can be recovered in a nondestructive state. ► These EECs contain 17 groups and can be classified into 54 types based on their shapes and sizes. ► The successive 3 stages of physical separation would enables the recovery of minor ingredients. - Abstract: Although printed circuit boards (PCBs) contain various elements, only the major elements (i.e., those with content levels in wt% or over grade) of and precious metals (e.g., Ag, Au, and platinum groups) contained within PCBs can be recycled. To recover other elements from PCBs, the PCBs should be properly disassembled as the first step of the recycling process. The recovery of these other elements would be beneficial for efforts to conserve scarce resources, reuse electric/electronic components (EECs), and eliminate environmental problems. This paper examines the disassembly of EECs from wasted PCBs (WPCBs) and the physical separation of these EECs using a self-designed disassembling apparatus and a 3-step separation process of sieving, magnetic separation, and dense medium separation. The disassembling efficiencies were evaluated by using the ratio of grinding area (Earea) and the weight ratio of the detached EECs (Eweight). In the disassembly treatment, these efficiencies were improved with an increase of grinder speed and grinder height. 97.7% (Earea) and 98% (Eweight) could be accomplished ultimately by 3 repetitive treatments at a grinder speed of 5500 rpm and a grinder height of 1.5 mm. Through a series of physical separations, most groups of the EECs (except for the diode, transistor, and IC chip groups) could be sorted at a relatively high separation efficiency of about 75% or more. To evaluate the separation efficiency with regard to the elemental composition, the
Investigation of the influence of inert and oxidizing atmospheres on the efficiency of decomposition of waste printed circuit boards (WPCBs)
Kumari, Anjan; Jha, Manis Kumar; Singh, Rajendra Prasad; Ranganathan, S.
Thermo-gravimetry was used for studying the influence of the furnace atmosphere during the pyrolysis waste circuit boards (WPCBs). Pyrolysis in argon atmosphere resulted in a continuous decrease of mass of the sample. Rapid mass loss occurred at about 573 K. Heating the WPCBs in air and oxygen atmospheres resulted in an increase in the mass of the sample in the early stages until rapid mass loss occurred at about 573 K. When pyrolysis of larger sample mass (about 5 g each) was carried out in tubular furnace, about 20.43 % mass loss was observed during the pyrolysis of WPCBs in a flowing stream of argon at 548 K during a period of 4 min. On the other hand, a maximum of about 2.26 % mass loss was recorded when the WPCBs were heated at about 600 K for the same time interval in the still air. The mass transfer during the pyrolysis of WPCBs in flowing stream of inert gas was also modeled. It is found that controlling the flow rate of inert gas and the geometry of the equipment can enhance the rate of mass loss significantly.
The principle of elaboration of the relay protection against short circuits between the closely placed phases of high voltage electrical line
Directory of Open Access Journals (Sweden)
Kiorsak M.
Full Text Available The article is devoted to the elaboration of the principle of relay protection against short circuits between the closely placed phases of higher voltage electrical line with self-compensation, based on the six phase's symmetrical components. It is shown that the unsymmetrical short circuits between the closely placed phases are characterized by appearance of zero and tertiary sequences of symmetrical components. This fact can be used to choose them for relay protection. The electrical basic circuits and formulas for calculation of the passive parameters of zero and tertiary filters of currents (voltages are done. It is presented the structural-functional basic circuit scheme for relay protection against short circuits between the closely placed phases of higher voltage electrical line with self-compensation.
Probing Atmospheric Electric Fields in Thunderstorms through Radio Emission from Cosmic-Ray-Induced Air Showers
Schellart, P; Buitink, S; Corstanje, A; Enriquez, J E; Falcke, H; Hörandel, J R; Nelles, A; Rachen, J P; Rossetto, L; Scholten, O; ter Veen, S; Thoudam, S; Ebert, U; Koehn, C; Rutjes, C; Alexov, A; Anderson, J M; Avruch, I M; Bentum, M J; Bernardi, G; Best, P; Bonafede, A; Breitling, F; Broderick, J W; Brüggen, M; Butcher, H R; Ciardi, B; de Geus, E; de Vos, M; Duscha, S; Eislöffel, J; Fallows, R A; Frieswijk, W; Garrett, M A; Grießmeier, J; Gunst, A W; Heald, G; Hessels, J W T; Hoeft, M; Holties, H A; Juette, E; Kondratiev, V I; Kuniyoshi, M; Kuper, G; Mann, G; McFadden, R; McKay-Bukowski, D; McKean, J P; Mevius, M; Moldon, J; Norden, M J; Orru, E; Paas, H; Pandey-Pommier, M; Pizzo, R; Polatidis, A G; Reich, W; Röttgering, H; Scaife, A M M; Schwarz, D J; Serylak, M; Smirnov, O; Steinmetz, M; Swinbank, J; Tagger, M; Tasse, C; Toribio, M C; van Weeren, R J; Vermeulen, R; Vocks, C; Wise, M W; Wucknitz, O; Zarka, P
We present measurements of radio emission from cosmic ray air showers that took place during thunderstorms. The intensity and polarization patterns of these air showers are radically different from those measured during fair-weather conditions. With the use of a simple two-layer model for the atmospheric electric field, these patterns can be well reproduced by state-of-the-art simulation codes. This in turn provides a novel way to study atmospheric electric fields.
Probing Atmospheric Electric Fields in Thunderstorms through Radio Emission from Cosmic-Ray-Induced Air Showers.
Schellart, P; Trinh, T N G; Buitink, S; Corstanje, A; Enriquez, J E; Falcke, H; Hörandel, J R; Nelles, A; Rachen, J P; Rossetto, L; Scholten, O; Ter Veen, S; Thoudam, S; Ebert, U; Koehn, C; Rutjes, C; Alexov, A; Anderson, J M; Avruch, I M; Bentum, M J; Bernardi, G; Best, P; Bonafede, A; Breitling, F; Broderick, J W; Brüggen, M; Butcher, H R; Ciardi, B; de Geus, E; de Vos, M; Duscha, S; Eislöffel, J; Fallows, R A; Frieswijk, W; Garrett, M A; Grießmeier, J; Gunst, A W; Heald, G; Hessels, J W T; Hoeft, M; Holties, H A; Juette, E; Kondratiev, V I; Kuniyoshi, M; Kuper, G; Mann, G; McFadden, R; McKay-Bukowski, D; McKean, J P; Mevius, M; Moldon, J; Norden, M J; Orru, E; Paas, H; Pandey-Pommier, M; Pizzo, R; Polatidis, A G; Reich, W; Röttgering, H; Scaife, A M M; Schwarz, D J; Serylak, M; Smirnov, O; Steinmetz, M; Swinbank, J; Tagger, M; Tasse, C; Toribio, M C; van Weeren, R J; Vermeulen, R; Vocks, C; Wise, M W; Wucknitz, O; Zarka, P
We present measurements of radio emission from cosmic ray air showers that took place during thunderstorms. The intensity and polarization patterns of these air showers are radically different from those measured during fair-weather conditions. With the use of a simple two-layer model for the atmospheric electric field, these patterns can be well reproduced by state-of-the-art simulation codes. This in turn provides a novel way to study atmospheric electric fields. PMID:25955053
Effects of the Physical Laboratory versus the Virtual Laboratory in Teaching Simple Electric Circuits on Conceptual Achievement and Attitudes Towards the Subject
Tekbiyik, Ahmet; Ercan, Orhan
Current study examined the effects of virtual and physical laboratory practices on students' conceptual achievement in the subject of electricity and their attitudes towards simple electric circuits. Two groups (virtual and physical) selected through simple random sampling was taught with web-aided material called "Electricity in Our…
Effects of Electric Contact Failure on Signal Transmission in the Lossy Circuits
Institute of Scientific and Technical Information of China (English)
CHEN Ya; SUN Bai-sheng
Based on the former research results of the influence of contact failure in ideal and unmatched circuits, this paper further studies theoretically the effects of contact failure on the digital signal transmission in the lossy circuits, which may happen widely in practical applications. Experiences show that even in high-quality lines, losses deform the voltage and current wave shapes owing to their effects on the amplitude of the various waves making up the over-all line voltage and current. Although the derivations show that the effects of contact failure in the lossy circuits on the signal transmission are quite complicated. The probability of occurrence of error codes can be increased significantly.
Improving the electromagnetic compatibility of track circuits with electric rolling stock of double power supply with induction traction motors and electrictraction network
Directory of Open Access Journals (Sweden)
N.G. Visin
Full Text Available In this article the research results of many authors on the effect of current interference from the existing electric rolling stock with induction traction motors (ITM on the track circuits and the possibility of exceeding the train traffic safety standards are used. The new promising scheme of power circuit for electric locomotive of double power supply with an ITM applying the intermediary high-frequency transformer for reducing significantly the interference effects to SCB and communication devices is developed.
Influence of seismic activity on the atmospheric electric field in Lisbon (Portugal from 1955 to 1991
Directory of Open Access Journals (Sweden)
Pier Francesco Biagi
Full Text Available
In the present study, we considered the influence of seismic activity on the atmospheric electric field recorded at Portela meteorological station (Lisbon, Portugal for the period from 1955 to 1991. To this end, an exploratory method was developed, which involved the selection of events for which the distance from the atmospheric electrical field sensor to the earthquake epicenter is smaller than the preparation radius of the event. This enabled the correlation of the atmospheric electric field variations with a quantity S, defined basically as the ratio of the earthquake preparation radius to the distance between the sensor and the event epicenter. The first results show promising perspectives, but clearly a more profound study is required, in which a careful analysis of the weather conditions and other variables, like atmospheric radon levels, must be considered.
Directory of Open Access Journals (Sweden)
N. H. Visin
Full Text Available The transitional processes in shunt circuit of traction engines, which armatures and excitation windings are connected in non-conducting direction as to the flowing power current, are considered in this paper. The changes in the control circuits of braking switch and in the shunt power circuit of traction engines with additional mounting a resistor of 0.5 Ohm are proposed. All this modernization will allow increasing greatly the operation reliability of power circuit of ЭР2Т and ЕПЛ2Т electric locomotives during their service life.
Atmospheric Electric Fields and Radon Daughter Deposition on Vegetation
Energy Technology Data Exchange (ETDEWEB)
Jeffers, D
Porstendoerfer has reported deposition velocities of unattached radon daughters measured above a growing wheat canopy which are ten times the values measured in a wind tunnel. It is suggested that this is the consequence of the enhancement of the natural electric field at the tips of the ears of wheat. (author)
Short- circuit tests of circuit breakers
Chorovský, P.
This paper deals with short-circuit tests of low voltage electrical devices. In the first part of this paper, there are described basic types of short- circuit tests and their principles. Direct and indirect (synthetic) tests with more details are described in the second part. Each test and principles are explained separately. Oscilogram is obtained from short-circuit tests of circuit breakers at laboratory. The aim of this research work is to propose a test circuit for performing indirect test.
Towards Photonic-Plasmonic Integrated Circuits: Study and Fabrication Of Electrically-Pumped Plasmonic Nano-Laser
Hseih, Chunhan Michael
For the next generation of optical communication, Photonic Integrated Circuits (PIC) and optoelectronic integrated circuits has been of great interest because of the possibility of integrating multiple optical components and electronics together to give high performance opto-electronic system on a small chip that can be produced cost-effectively. Integrated semiconductor laser, as the main light source for generating signals in optical communications, is one of the most important function on a photonic integrated circuit. In the recent advancements in nanophotonics, strong confinement of light in strongly-guiding optical waveguide structure comparing to conventional structures, has been used to improve certain performances of on-chip semiconductor lasers and miniaturize the laser device sizes. However, compared to electronics, even with use of nanophotonic device technology, optoelectronic device footprints are still relatively large due to the diffraction limit of light, which poses a limit on the sizes of optoelectronic devices. Plasmonic photonic device area has been an intensive field of research that utilizes plamonic photonic waveguides to confine light smaller than the diffraction limit through the effect of surface plasmon polariton, a coupling between photons and plasmon along a metal-dielectric interface. In this dissertation, an electrically pumped Plasmonic nanolaser has been designed using 2D-FDTD simulation. The nanolaser has the potential of lasing utilizing achievable optical gain in the typical compound (group III-V) semiconductor materials. The laser electrical pumping structure is compatible with device integration on silicon photonics platform utilizing silicon-on-insulator (SOI) substrate. Electrically pumped thin film based laser structure is shown to be realizable with the use of TCO material as transparent electrodes on the waveguide cladding. Indium oxide (In2O3) and Zinc-Indium-Tin-Oxide (ZITO) deposited by ion-beam-assisted deposition
Conceptual difficulties experienced by senior high school students of electrochemistry: Electric circuits and oxidation-reduction equations
Garnett, Pamela J.; Treagust, David F.
The purpose of this research was to investigate students' understanding of electrochemistry following a course of instruction. A list of conceptual and propositional knowledge statements was formulated to identify the knowledge base necessary for students to understand electric circuits and oxidation-reduction equations. The conceptual and propositional knowledge statements provided the framework for the development of a semistructured interview protocol which was administered to 32 students in their final year of high school chemistry. The interview questions about electric circuits revealed that several students in the sample were confused about the nature of electric current both in metallic conductors and in electrolytes. Students studying both physics and chemistry were more confused about current flow in metallic conductors than students who were only studying chemistry. In the section of the interview which focused on oxidation and reduction, many students experienced problems in identifying oxidation-reduction equations. Several misconceptions relating to the inappropriate use of definitions of oxidation and reduction were identified. The data illustrate how students attempted to make sense of the concepts of electrochemistry with the knowledge they had already developed or constructed. The implications of the research are that teachers, curriculum developers, and textbook writers, if they are to minimize potential misconceptions, need to be cognizant of the relationship between physics and chemistry teaching, of the need to test for erroneous preconceptions about current before teaching about electrochemical (galvanic) and electrolytic cells, and of the difficulties experienced by students when using more than one model to explain scientific phenomena.
Electronic meter with custom integrated circuit for electric energy measurement; Medidor eletronico de energia eletrica com circuito integrado dedicado
Energy Technology Data Exchange (ETDEWEB)
Caldas, Roberto Pereira
The design and implementation of an electrical energy electronic meter for operation at low voltages, according to two steps of development carried out in Centro de Pesquisas de Energia Eletrica - CEPEL is described. In the first step, an electronic meter with discrete commercial components has been developed, in order to demonstrate to the Brazilian power suppliers the feasibility of such a device for electrical energy metering and charging. The second step was constituted by the design of an integrated circuit, aiming the reduction of the cost of the meter as well as the enhancement of its reliability. Several techniques of electrical energy measurement are presented. The meter with discrete components makes use of a time division multiplier (TDM), in order to determine the active power in the load. Voltage and current levels have been reduced through the use of voltage and current sensors compatible with the TDM's inputs. A V-F converter employing continuos integration, has been used for the determination of the energy consumed by the load through the integration of the TDM's output signal. Most of the discrete components of the meter have been replaced by the dedicated integrated circuit. The TDM has remained essentially the same, but the V-F converter has been changed into a dual-slope one, which is more adequate for implementation in a single chip. The tests performed with the prototypes of the meter including both the meter with discrete components and the meter with the custom-made integrated circuit have presented measurement errors of less the 0,2 %. The initial goal, according to Brazilian specifications of electromechanical meters and international specifications for electronic meters, was 1 %. (author)
System and method to determine electric motor efficiency using an equivalent circuit
Energy Technology Data Exchange (ETDEWEB)
Lu, Bin; Habetler, Thomas G.
A system and method for determining electric motor efficiency includes a monitoring system having a processor programmed to determine efficiency of an electric motor under load while the electric motor is online. The determination of motor efficiency is independent of a rotor speed measurement. Further, the efficiency is based on a determination of stator winding resistance, an input voltage, and an input current. The determination of the stator winding resistance occurs while the electric motor under load is online.
Testable Subsystems Generation for Fault Detection and Isolation Using a Structural Matching Rank Algorithm Testability of an Electrical Circuit
Directory of Open Access Journals (Sweden)
Benazzouz Djamel
Full Text Available In this study, an advanced way of dealing with testable subsystems and residual generation for fault detection and isolation based on structural analysis is presented. The developed technique considers execution issues; therefore, it has a more realistic point of view compared to classical structural approaches available in the literature. First, theoretical aspects of structural analysis are considered and introduced. Then the way of incorporating them to test the structural proprieties is explained. Finally, we show how the proposed (upgraded matching rank algorithm can be used in order to choose the most suited matching that leads to computational sequences and detection tests. The method is demonstrated using an electrical circuit.
Optical correlator using very-large-scale integrated circuit/ferroelectric-liquid-crystal electrically addressed spatial light modulators
Turner, Richard M.; Jared, David A.; Sharp, Gary D.; Johnson, Kristina M.
The use of 2-kHz 64 x 64 very-large-scale integrated circuit/ferroelectric-liquid-crystal electrically addressed spatial light modulators as the input and filter planes of a VanderLugt-type optical correlator is discussed. Liquid-crystal layer thickness variations that are present in the devices are analyzed, and the effects on correlator performance are investigated through computer simulations. Experimental results from the very-large-scale-integrated / ferroelectric-liquid-crystal optical-correlator system are presented and are consistent with the level of performance predicted by the simulations.
Electrical characterization of atmospheric pressure DBD in air
International Nuclear Information System (INIS)
Atmospheric pressure dielectric barrier discharge (DBD) in air was generated between two rectangular copper electrodes covering the lower electrode with a dielectric (glass or polycarbonate -PC) using low frequency (line frequency-50Hz) high voltage power supply. The discharge was studied for inter-electrode gap spacing in the range of 2 mm – 5 mm and their influence on breakdown voltage. Voltage-current characteristics and the analysis of the distribution of current pulses per half cycle of the current waveform indicated that the discharge is more uniform in 3 mm inter-electrode gap spacing with PC as a dielectric rather than glass. (author)
Network model and short circuit program for the Kennedy Space Center electric power distribution system
Assumptions made and techniques used in modeling the power network to the 480 volt level are discussed. Basic computational techniques used in the short circuit program are described along with a flow diagram of the program and operational procedures. Procedures for incorporating network changes are included in this user's manual.
Fluctuations of Entropy Production in Partially Masked Electric Circuits: Theoretical Analysis
Chiang, K. -H.; Chou, C.-W.; Lee, C. -L.; Lai, P. -Y.; Chen, Y. -F.
In this work we perform theoretical analysis about a coupled RC circuit with constant driven currents. Starting from stochastic differential equations, where voltages are subject to thermal noises, we derive time-correlation functions, steady-state distributions and transition probabilities of the system. The validity of the fluctuation theorem (FT) is examined for scenarios with complete and incomplete descriptions.
Study of the selective effect on cells induced by nanosecond pulsed electric field with the resistor-capacitor circuit model
Institute of Scientific and Technical Information of China (English)
Xu Fei; Xiao Dengming; Li Zhaozhi
A resistor-capacitor (RC) circuit model is proposed to study the effect of nanosecond pulsed electric field on cells according to the structure and electrical parameters of cells. After a nanosecond step field has been applied, the variation of voltages across cytomembrane and mitochondria membrane both in normal and in malignant cells are studied with this model. The time for selectively targeting the mitochondria membrane and malignant cell can be evaluated much easily with curves that show the variation of voltage across each membrane with time. Ramp field is the typical field applied in electrobiology. The voltages across each membrane induced by ramp field are analyzed with this model. To selectively target the mitochondria membrane, proper range of ramp slope is needed. It is relatively difficult to decide the range of a slope to selectively affect the malignant cell. Under some conditions, such a range even does not exist.
Spectral characteristics of atmospheric pressure and electric field variations under severe weather conditions at high latitudes
Kasatkina, E. A.; Shumilov, O. I.; Vinogradov, Y. A.; Vasilyev, A. N.
International audience The time-dependent relationships between atmospheric parameters (electric field, positive and negative conductivity, variations of atmospheric pressure) and different meteorological phenomena (rain, fogs, snowstorms, thunderstorms) were investigated through spectral analysis. These parameters were measured with help of a high-latitude computer-aided complex installed at Apatity (66.5 N, 33.4 E). The complex consists of three spaced microbarographs for measurements of...
Atmospheric electrical field measurements near a fresh water reservoir and the formation of the lake breeze
Directory of Open Access Journals (Sweden)
Francisco Lopes
Full Text Available In order to access the effect of the lakes in the atmospheric electrical field, measurements have been carried out near a large man-made lake in southern Portugal, the Alqueva reservoir, during the ALqueva hydro-meteorological EXperiment 2014. The purpose of these conjoint experiments was to study the impact of the Alqueva reservoir on the atmosphere, in particular on the local atmospheric electric environment by comparing measurements taken in the proximity of the lake. Two stations 10 km apart were used, as they were located up- and down-wind of the lake (Amieira and Parque Solar, respectively, in reference to the dominant northwestern wind direction. The up-wind station shows lower atmospheric electric potential gradient (PG values than the ones observed in the down-wind station between 12 and 20 UTC. The difference in the atmospheric electric PG between the up-wind and the down-wind station is ~30 V/m during the day. This differential occurs mainly during the development of a lake breeze, between 10 and 18 UTC, as a consequence of the surface temperature gradient between the surrounding land and the lake water. In the analysis presented, a correlation is found between the atmospheric electric PG differences and both wind speed and temperature gradients over the lake, thus supporting the influence of the lake breeze over the observed PG variation in the two stations. Two hypotheses are provided to explain this observation: (1 The air that flows from the lake into the land station is likely to increase the local electric conductivity through the removal of ground dust and the transport of cleaner air from higher altitudes with significant light ion concentrations. With such an increase in conductivity, it is expected to see a reduction of the atmospheric electric PG; (2 the resulting air flow over the land station carries negative ions formed by wave splashing in the lake's water surface, as a result of the so-called balloelectric effect
Dell'Isola, Francesco; Vestroni, Fabrizio; Vidoli, Stefano
A novel technique for damage detection of structures is introduced and discussed. It is based on purely electric measurements of the state variables of an electric network coupled to the main structure through a distributed set of piezoelectric patches. The constitutive parameters of this auxiliary network are optimized to increase the sensitivity of global measurements- as the frequency, response functions relative to selected electric degrees of freedom-with respect to a given class of vari...
Non-stationary corona around multi-point system in atmospheric electric field: I. Onset electric field and discharge current
Bazelyan, E. M.; Raizer, Yu. P.; Aleksandrov, N. L.
The properties of a non-stationary glow corona maintained near the tips of a multi-point ground system in a time-varying thundercloud electric field have been studied numerically and analytically. Computer and analytical models were developed to simulate the corona discharge initiated from a system of identical vertical conductive electrodes distributed uniformly over a grounded plane surface. The simulation was based on a solution of the electrostatic equation for electric field and continuity equations for light and aerosol ions. The development of individual corona space charge layers from different points and the formation of a united plane layer were considered. The effect of system dimensions and that of the distance between electrodes on the external electric field corresponding to corona onset near the rod tips was investigated. The evolution in time of the corona current was calculated for systems with various numbers of coronating rods in time-varying atmospheric electric field. In the limit of infinite number of coronating rods, reasonable agreement was obtained between numerical calculations and analytical theory considering the effect of surrounding rods on the corona discharge from a given rod in a simplified integral way. Conditions were determined under which the corona properties of a multi-point system are similar to the properties of a plane surface emitting ions into the atmosphere. In this case, the corona current density is governed by the time derivative of the thundercloud electric field and is independent of the ion mobility and of the coronating system dimensions. The total corona space charge injected into the atmosphere per unit area by a given instant is controlled by the thundercloud electric field at this instant and depends on the geometrical parameters of the system only indirectly, through the corona onset atmospheric electric field. This simple model could be used to simulate a corona discharge during thunderstorms at the earth�
Charge Yield at Low Electric Fields: Considerations for Bipolar Integrated Circuits
Johnston, A. H.; Swimm, R. T.; Thorbourn, D. O.
A significant reduction in total dose damage is observed when bipolar integrated circuits are irradiated at low temperature. This can be partially explained by the Onsager theory of recombination, which predicts a strong temperature dependence for charge yield under low-field conditions. Reduced damage occurs for biased as well as unbiased devices because the weak fringing field in thick bipolar oxides only affects charge yield near the Si/SiO2 interface, a relatively small fraction of the total oxide thickness. Lowering the temperature of bipolar ICs - either continuously, or for time periods when they are exposed to high radiation levels - provides an additional degree of freedom to improve total dose performance of bipolar circuits, particularly in space applications.
Student use of model-based reasoning when troubleshooting an electric circuit
Dounas-Frazer, Dimitri
Troubleshooting systems is an integral part of experimental physics in both research and educational settings. Accordingly, ability to troubleshoot is an important learning goal for undergraduate physics lab courses. We investigate students' model-based reasoning on a troubleshooting task using data collected in think-aloud interviews during which pairs of students from two institutions attempted to diagnose and repair a malfunctioning circuit. Our analysis scheme was informed by the Experimental Modeling Framework, which describes physicists' use of mathematical and conceptual models when reasoning about experimental systems. We show that system and subsystem models were crucial for the evaluation of repairs to the circuit and played an important role in some troubleshooting strategies. Finally, drawing on data from interviews with electronics instructors from a broad range of institution types, we outline recommendations for model-based approaches to teaching and learning troubleshooting skills.
High-fidelity pulse density modulation in neuromorphic electric circuits utilizing natural heterogeneity
Utagawa, Akira; Asai, Tetsuya; Amemiya, Yoshihito
Hospedales et al. have recently proposed a neural network model of the "vestibulo-ocular reflex" (VOR) in which a common input was given to multiple nonidentical spiking neurons that were exposed to uncorrelated temporal noise, and the output was represented by the sum of these neurons. Although the function of the VOR network is equivalent to pulse density modulation, the neurons' non-uniformity and temporal noises given to the neurons were shown to improve the output spike's fidelity to the analog input. In this paper, we propose a CMOS analog circuit for implementing the VOR network that exploits the non-uniformity of real MOS devices. Through extensive laboratory experiments using discrete MOS devices, we show that the output's fidelity to the input pulses is clearly improved by using multiple neuron circuits, in which the non-uniformity is naturally embedded into the devices.
Multi-stations Observations of the Atmospheric Electrical Parameters during Geomagnetic Disturbances
Nepolian, Jeni Victor; Frank-Kamenetsky, Alexander; Panneerselvam, C.; Manu, S.; Anil Kumar
The effects of geomagnetic disturbances on the variation of atmospheric electric field over Maitri (70o 45' S, 11o44' E), Dome C (75° 06' S, 123° 20' E) and Vostok (78° 27' S, 106° 52' E) Antarctic research stations are presented in this work. For the first time the paper reports simultaneous observations of the atmospheric electric field from 2010 to 2012 of over three high latitude stations in Southern Hemisphere, and its associated changes due to geomagnetic disturbances. Near surface electric fields obtained from the three stations are analyzed. It is noted that the amplitude of change in surface electric field is highly dependent on the magnetic latitude during geomagnetic disturbances. The maximum deviation is observed near to the geomagnetic pole (Dome C) during strong magnetic perturbation, but not on the foci of the convection cells. It is due to the effective downward mapping of large scale horizontal ionospheric electric field. Interestingly, the phase of downward current is highly associated with magnetospheric electric field, moreover, its imprint is clearly observed in the magnetic and electric field variations on the earth's surface. The present observations provide an evidence for the changes on surface electric field due to spatial extension of convection cell. The inferences will be discussed in the conference.
An improved electrical and thermal model of a microbolometer for electronic circuit simulation
D. Würfel; Vogt, H.
The need for uncooled infrared focal plane arrays (IRFPA) for imaging systems has increased since the beginning of the nineties. Examples for the application of IRFPAs are thermography, pedestrian detection for automotives, fire fighting, and infrared spectroscopy. It is very important to have a correct electro-optical model for the simulation of the microbolometer during the development of the readout integrated circuit (ROIC) used for IRFPAs. The microbolometer as the sens...
Investigation and calculation of valleys of outgoing from substation grounding conductors for short-circuit in single-phase short of electrical grid
V.I. Nizhevskyi; I.V. Nizhevskyi; Ynoyatov, B.; Nasryddyny, S.
Introduction. Earthing device electrical substation in modern conditions must meet both the requirements of electrical safety of people and animals, as well as electromagnetic compatibility requirements established her electrical equipment. These requirements are intended to address issues of protection against surges and interference caused by lightning impulse currents and switching. Aim. To investigate the distribution of single-phase short-circuit current in the substation grounding devic...
Structural-Damage Detection by Distributed Piezoelectric Transducers and Tuned Electric Circuits
dell'Isola, F; Vidoli, S
A novel technique for damage detection of structures is introduced and discussed. It is based on purely electric measurements of the state variables of an electric network coupled to the main structure through a distributed set of piezoelectric patches. The constitutive parameters of this auxiliary network are optimized to increase the sensitivity of global measurements- as the frequency, response functions relative to selected electric degrees of freedom-with respect to a given class of variations in the structural-mechanical properties. Because the proposed method is based on purely electric input and output measurements, it allows for accurate results in the identification and localization of damages. Use of the electric frequency-response function to identify the mechanical damage leads to nonconvex optimization problems; therefore the proposed sensitivity-enhanced identification procedure becomes computationally efficient if an a priori knowledge about the damage is available.
Simultaneous measurement of the horizontal components of the earth's electric field in the atmosphere and in the ionosphere
Kelley, M. C.; Mozer, F. S.
Simultaneous measurements have been made of the ionospheric electric field at altitudes above 100 km (with rockets and radar) and of the atmospheric electric field at an altitude of about 30 km (with balloons). These results show that the horizontal components of the electric field at 30 km were essentially equal to the ionospheric electric field, as has been argued previously on theoretical grounds.
Circuit modification in electrical field flow fractionation systems generating higher resolution separation of nanoparticles.
Tasci, Tonguc O; Johnson, William P; Fernandez, Diego P; Manangon, Eliana; Gale, Bruce K
Compared to other sub-techniques of field flow fractionation (FFF), cyclical electrical field flow fractionation (CyElFFF) is a relatively new method with many opportunities remaining for improvement. One of the most important limitations of this method is the separation of particles smaller than 100nm. For such small particles, the diffusion rate becomes very high, resulting in severe reductions in the CyElFFF separation efficiency. To address this limitation, we modified the electrical circuitry of the ElFFF system. In all earlier ElFFF reports, electrical power sources have been directly connected to the ElFFF channel electrodes, and no alteration has been made in the electrical circuitry of the system. In this work, by using discrete electrical components, such as resistors and diodes, we improved the effective electric field in the system to allow high resolution separations. By modifying the electrical circuitry of the ElFFF system, high resolution separations of 15 and 40nm gold nanoparticles were achieved. The effects of applying different frequencies, amplitudes and voltage shapes have been investigated and analyzed through experiments.
直流与交流电气线路中铜导线短路痕迹的分析%Analysis on short circuit trace of copper wire in direct and alternating current electric circuits
Institute of Scientific and Technical Information of China (English)
王连铁; 高伟; 赵长征; 袁晓光
直流电气线路及交流电气线路中铜导线发生短路故障时所形成的熔痕的组织特征不同,为区分二者之间的差别,利用模拟试验手段制备出金相样品,并采用宏观分析、金相分析等各种技术手段进行分析总结,归纳出二者发生短路故障时所形成的痕迹特征规律.模拟研究结果表明,直流线路一次短路熔痕的金相组织以细小的柱状晶为主,且孔洞较少;在交流线路中,一次短路故障形成的熔痕的金相组织胞状晶较多,且交、直流电气线路中铜导线发生短路故障时所形成的熔痕的组织特征明显不同,这些特征可用于实际鉴定工作中.%The microstructural characteristics of melted marks formed due to the short circuit fault of copper wire in direct current(DC) and alternating current(AC) electric circuits are different.In order to distinguish the difference between them,the metallographic samples were prepared through the simulation tests.In addition,such technical means as macro analysis and metallographic analysis were used to analyze and summarize the characteristics of the mark formed due to the short circuit fault in DC and AC electric circuits.The simulation results show that the microstructures of melted marks formed due to the primary short circuit fault in DC circuit are mainly composed of fine columnar crystals with fewer holes.However,the microstructures of melted marks formed due to the primary short circuit fault in AC circuit contain more cellular crystals.Furthermore,the microstructural characteristics of melted marks formed due to the short circuit faults of copper wire in DC and AC electric circuits are obviously different,and can provide the reference for the actual identification work.
Variation of fair weather atmospheric electricity at Marsta Observatory, Sweden, 1993-1998
Israelsson, S.; Tammet, H.
A modified atmospheric electrical station of the Kasemir-Dolezalek construction is continuously operating in the Marsta Observatory /(59°56'N,17°35'W) located in rural area 10km north of Uppsala, Sweden. The routinely recorded parameters are the electric field, positive and negative polar conductivities of air, and space charge density. The effect of possible local anthropogenic air pollution on the fair weather atmospheric electric measurements at Marsta is estimated according to Sheftel et al., 1994a (J. Geophys. Res. 99, 10,793) by comparing the Sunday and weekday values of air conductivity. The effect of local air pollution appears essentially less than at other evaluated continental atmospheric electric stations. The natural periodic variations of fair weather electric field and vertical air-earth current averaged over many years at Marsta are compared with the periodic variations of electric field measured during the Carnegie expeditions over the oceans where the global component of variations dominates over the local component. The diurnal variations of electric field and vertical current at Marsta are well correlated with the Carnegie curve during winter and ill correlated during summer. The correlation coefficient reaches 98% for the winter measurements of vertical air-earth current. In addition, a test has been carried out for a hypothesis that numerical reduction of the data according to the local temperature and wind variation could suppress the local component of fair weather atmospheric electric variations and thus help to study the global component of variation. The hypothesis proved to be inadequate. The reduction suppresses the annual variation, but the shape of the diurnal variation remains the same and the correlation with the Carnegie curve is even worse than in the case of unreduced measurements. The Marsta Observatory is recommended as a basis station for long-term routine atmospheric electric measurements to gather data for the study of
Influence of atmospheric electric fields on the radio emission from extensive air showers
DEFF Research Database (Denmark)
Trinh, T. N. G.; Scholten, O.; Buitink, S.;
The atmospheric electric fields in thunderclouds have been shown to significantly modify the intensity and polarization patterns of the radio footprint of cosmic-ray-induced extensive air showers. Simulations indicated a very nonlinear dependence of the signal strength in the frequency window of ...
First results of fair-weather atmospheric electricity measurements in Northeast India
Indian Academy of Sciences (India)
A Guha; B K De; S Gurubaran; S S De; K Jeeva
During the month of March 2006, a short campaign was conducted to measure fair-weather atmospheric electricity parameters in Tripura, Northeast India (23.50°N, 91.25°E). The campaign was the first of its kind in this region of the globe. The main objective of the campaign was to characterize the diurnal variation of three parameters namely vertical potential gradient (), vertical air–earth current density (Jz) and atmospheric electrical conductivity () in fair-weather conditions. The diurnal variation of and Jz over sixteen fair-weather days shows two distinct maxima around 14UT and 20UT and a minimum around 03UT. The average vertical potential gradient is found to be 108V·m−1 and air–earth current density 1.85 pA·m−2. The average bipolar atmospheric electrical conductivity at the ground level is found to be 19.6 fS·m−1. An excellent positive correlation between and Jz is found, with a correlation coefficient of 0.96. A comparative study with Carnegie universal variation shows 70% correlation with observed variation of vertical potential gradient during the period of the campaign. The results are discussed in view of difficulty as well as possibility of getting global signatures in atmospheric electricity measurements made from tropical land stations.
Probing atmospheric electric fields in thunderstorms through radio emission from cosmic-ray induced air showers
Trinh, Gia Thi Ngoc; Schellart, Pim; Buitink, Stijn; Corstanje, Arthur; Ebert, Ute; Enriquez, Emilio; Falcke, Heino; Horandel, Jörg R.; Nelles, Anna; Rachen, Jörg Paul; Rutjes, Casper; Scholten, Olaf; ter Veen, Sander; Thoudam, Satyendra
Energetic cosmic rays impinging on the atmosphere create a particle avalanche called extensive air shower. In the leading plasma of this shower electric currents are induced that generate the emission of radio waves which have been detected with LOFAR, an array of a large number of simple antennas p
Influence of atmospheric electric fields on the radio emission from extensive air showers
Trinh, T. N. G.; Scholten, O.; Buitink, S.; van den Berg, A. M.; Corstanje, A.; Ebert, U.; Enriquez, J. E.; Falcke, H.; Horandel, J. R.; Kohn, C.; Nelles, A.; Rachen, J. P.; Rossetto, L.; Rutjes, C.; Schellart, P.; Thoudam, S.; ter Veen, S.; de Vries, K. D.
The atmospheric electric fields in thunderclouds have been shown to significantly modify the intensity and polarization patterns of the radio footprint of cosmic-ray-induced extensive air showers. Simulations indicated a very nonlinear dependence of the signal strength in the frequency window of 30-
基于Pockels效应的大气电场测量研究%Study on atmospheric electric field measurement based on Pockels effect
Institute of Scientific and Technical Information of China (English)
周龙; 行鸿彦; 张志鹏; 陈洁; 吴安坤
为解决常用场磨式大气电场仪体积大、机械磨损严重、易受电磁干扰、测量带宽窄等问题,在研究分析Pockels效应原理的基础上,提出应用Pockels效应来测量大气电场的方法.对晶体、光源的选择及传感器设计中出现的问题进行了分析,设计了一种基于Pockels效应原理的脉冲电场传感器,该传感系统包括稳定高效的光源、Pockels晶体探头、数据采集及处理电路.通过模拟仿真,说明了这种测量方法是可行的,为进一步研制大气电场测量传感器,提高其性能提供了理论依据.%In order to solve some problems of the common atmospheric electric field mill, such as bulk mass, serious abrasion, electromagnetic interference and narrow bandwidth, this paper advanced a new way to measure atmospheric electric field which is based on the research of Pockels effect, analyzed the choice problem of crystal and light source, and others which appeared during the course of design this sensor, and designed a pulse electric field sensor which was based on Pockels effect. This system consist of stable and high-efficiency light source, Pockels detector, data acquisition and processing circuit. According to the analog simulation, this method of measuring atmospheric electric field is workable, in this way it afford a basis for further design of this atmospheric electric field sensor and improving tt' s performance.
History of Physics as a Tool to Detect the Conceptual Difficulties Experienced by Students: The Case of Simple Electric Circuits in Primary Education
Leone, Matteo
The present paper advocates the use of History of Science into the teaching of science in primary education through a case study in the field of electricity. In this study, which provides both historical and experimental evidence, a number of conceptual difficulties faced by early nineteenth century physicists are shown to be a useful tool to detect 5th grade pupils' conceptions about the simple electric circuits. This result was obtained through the administration of schematics showing circuital situation inspired to early 1800s experiments on the effects of electric current on water electrolysis and on the behaviour of magnetic compasses. It is also shown that the detecting of pupils' alternative ideas about electric current in a circuit is highly dependent on the survey methodology (open ended questions and drawings, multiple-choice item, connecting card work, and history of science tasks were considered in this study) and that the so-called "unipolar model" of electric circuit is more pervasive than previously acknowledged. Finally, a highly significant hybrid model of electric current is identified.
车载网络技术对汽车传统电路的影响%Influence of Vehicle Network Technology on Traditional Vehicle electric Circuit
Institute of Scientific and Technical Information of China (English)
文章论述了车载网络技术对汽车传统电路的影响。通过比较前照灯的传统电路与自适应前照明系统工作原理和布线方式等方面的不同,说明传统汽车电路已经远远不能满足智能汽车的需要。%The thesis discuss influence of vehicle network technology on traditional vehicle electric circuit. According to comparing with the headlamp traditional electric circuit and adaptive font-lighting system , we conclude that the tradi-tional automobile electric circuit data transmission has been far from satisfying the needs of the smart car.
Relationship of ground-level aerosol concentration and atmospheric electric field at three observation sites in the Arctic, Antarctic and Europe
Kubicki, Marek; Odzimek, Anna; Neska, Mariusz
Aerosol number concentrations in the particle size range from ~ 10 nm to 1 μm and vertical electric field strength in the surface layer was measured between September 2012 and December 2013 at three observation sites: mid-latitude station Swider, Poland, and, for the first time, in Hornsund in the Arctic, Spitsbergen, and the Antarctic Arctowski station in the South Shetland Islands. The measurements of aerosol concentrations have been performed simultaneously with measurements of the electric field with the aim to assess the local effect of aerosol on the electric field Ez near the ground at the three stations which at present form a network of atmospheric electricity observatories. Measurements have been made regardless of weather conditions at Swider and Arctowski station and mostly on fair-weather days at Hornsund station. The monthly mean particle number concentrations varied between 580 and 2100 particles cm- 3 at Arctowski, between 90 and 1270 particles cm- 3 in Hornsund, and between 6700 and 14,000 particles cm- 3 in the middle latitude station Swider. Average diurnal variations of the ground-level electric field Ez and particle number concentrations in fair-weather conditions were independent of each other for Arctowski and Hornsund stations. At Swider station the diurnal variation is usually characterized by an increase of aerosol concentration in the evening which results in the increased electric field. The assumption of neglecting the influence of varying aerosol concentration on the variation of the electric field in the polar regions, often adopted in studies, is confirmed here by the observations at Arctowski and Hornsund. The results of aerosol observations are also compared with modelled aerosol concentrations for global atmospheric electric circuit models.
Electrical and optical properties of Ar/NH3 atmospheric pressure plasma jet
Chang, Zheng-Shi; Yao, Cong-Wei; Chen, Si-Le; Zhang, Guan-Jun
Inspired by the Penning effect, we obtain a glow-like plasma jet by mixing ammonia (NH3) into argon (Ar) gas under atmospheric pressure. The basic electrical and optical properties of an atmospheric pressure plasma jet (APPJ) are investigated. It can be seen that the discharge mode transforms from filamentary to glow-like when a little ammonia is added into the pure argon. The electrical and optical analyses contribute to the explanation of this phenomenon. The discharge mode, power, and current density are analyzed to understand the electrical behavior of the APPJ. Meanwhile, the discharge images, APPJ's length, and the components of plasma are also obtained to express its optical characteristics. Finally, we diagnose several parameters, such as gas temperature, electron temperature, and density, as well as the density number of metastable argon atoms of Ar/NH3 APPJ to help judge the usability in its applications.
Properties and application of a multichannel integrated circuit for low-artifact, patterned electrical stimulation of neural tissue
Hottowy, Paweł; Skoczeń, Andrzej; Gunning, Deborah E.; Kachiguine, Sergei; Mathieson, Keith; Sher, Alexander; Wiącek, Piotr; Litke, Alan M.; Dąbrowski, Władysław
Objective Modern multielectrode array (MEA) systems can record the neuronal activity from thousands of electrodes, but their ability to provide spatio-temporal patterns of electrical stimulation is very limited. Furthermore, the stimulus-related artifacts significantly limit the ability to record the neuronal responses to the stimulation. To address these issues, we designed a multichannel integrated circuit for patterned MEA-based electrical stimulation and evaluated its performance in experiments with isolated mouse and rat retina. Approach The Stimchip includes 64 independent stimulation channels. Each channel comprises an internal digital-to-analog converter that can be configured as a current or voltage source. The shape of the stimulation waveform is defined independently for each channel by the real-time data stream. In addition, each channel is equipped with circuitry for reduction of the stimulus artifact. Main results Using a high-density MEA stimulation/recording system, we effectively stimulated individual retinal ganglion cells (RGCs) and recorded the neuronal responses with minimal distortion, even on the stimulating electrodes. We independently stimulated a population of RGCs in rat retina and, using a complex spatio-temporal pattern of electrical stimulation pulses, we replicated visually-evoked spiking activity of a subset of these cells with high fidelity. Significance Compared with current state-of-the-art MEA systems, the Stimchip is able to stimulate neuronal cells with much more complex sequences of electrical pulses and with significantly reduced artifacts. This opens up new possibilities for studies of neuronal responses to electrical stimulation, both in the context of neuroscience research and in the development of neuroprosthetic devices. PMID:23160018
Directory of Open Access Journals (Sweden)
V. I. Nizhevskyi
Full Text Available Introduction. Earthing device electrical substation in modern conditions must meet both the requirements of electrical safety of people and animals, as well as electromagnetic compatibility requirements established her electrical equipment. These requirements are intended to address issues of protection against surges and interference caused by lightning impulse currents and switching. Aim. To investigate the distribution of single-phase short-circuit current in the substation grounding devices. Task. On the basis of the proposed design scheme of substitution substation grounding device, consisting of a substation earthing system and «cable-supported» an algorithm for calculating the resistance of the grounding device substation and distribution of single-phase short-circuit current on the circuit elements. Method. Mathematical modeling and calculation engine. Results. On the basis of calculations and studies analyzed the current distribution of single-phase short-circuit between the substation earthing system and earthing «rope-reliance». Studies carried out for the actual range of variation of the circuit parameters, showed that the earthing resistance substation substantially affects the current distribution in the one-phase short circuit fault. For example, using the graph shows that with increasing resistance grounding system of "rope-supported" the proportion of single-phase short-circuit current flowing from the substation earthing increases, while the proportion of single-phase short-circuit current flowing from the grounding device supports decreases and vice versa. In addition, when rationing grounding systems at substations for the touch voltage is necessary to analyze all the possible modes of operation of the network, which is substationed. Conclusion. The results obtained are recommended to take into account in the design of grounding systems at substations.
Wideband energy harvesting using a combination of an optimized synchronous electric charge extraction circuit and a bistable harvester
International Nuclear Information System (INIS)
The challenge of variable vibration frequencies for energy harvesting calls for the development of wideband energy harvesters. Bistability has been proven to be a potential solution. Optimization of the energy extraction is another important objective for energy harvesting. Nonlinear synchronized switching techniques have demonstrated some of the best performances. This paper presents a novel energy harvesting solution which combines these two techniques: the OSECE (optimized synchronous electric charge extraction) technique is used along with a BSM (buckled-spring–mass) bistable generator to achieve wideband energy harvesting. The effect of the electromechanical coupling coefficient on the harvested power for the bistable harvester with the nonlinear energy extraction technique is discussed for the first time. The performances of the proposed solution for different levels of electromechanical coupling coefficients in the cases of chirp and noise excitations are compared against the performances of the bistable harvester with the standard technique. It is shown that the OSECE technique is a much better option for wideband energy harvesting than the standard circuit. Moreover, the harvested energy is drastically increased for all excitations in the case of low electromechanical coupling coefficients. When the electromechanical coupling coefficient is high, the performance of the OSECE technique is not as good as the standard circuit for forward sweeps, but superior for the reverse sweep and band-limited noise cases. However, considering that real excitation signals are more similar to noise signals, the OSECE technique enhances the performance. (paper)
Development of hydraulic power unit and accumulator charging circuit for electricity generation, storage and distribution
Institute of Scientific and Technical Information of China (English)
C.N.Okoye; JIANG Ji-hai; LIU Hai-chang
It is the purpose of the present paper to convert hydraulic energy to electric energy and saves both the pressure and electrical energy for re - use during the next system upstroke using two secondary units coupled to induction motor to drive cylinder loads. During upstroke operation, the variable pump/motor (P/M) driven by both electric motor and the second (P/M) works as hydraulic pump and output flow to the cylinders which drive the load. During load deceleration, the cylinders work as pump while the operation of the two secondary units are reversed, the variable (P/M) works as a motor generating a torque with the electric motor to drive the other(P/M) which transforms mechanical energy to hydraulic energy that is saved in the accumulator. When the en-ergy storage capacity of the accumulator is attained as the operation continues, energy storage to the accumulator is thermostatically stopped while the induction motor begins to work as a generator and generates electricity that is stored in the power distribution unit. Simulations were performed using a limited PT2 Block, I.e. 2nd-ordertransfer function with limitation of slope and signal output to determine suitable velocity of the cylinder which will match high performance and system stability. A mathematical model suited to the simulation of the hydrau-lic accumulator both in an open-or close-loop system is presented. The quest for improvement of lower energy capacity storage, saving and re-utilization of the conventional accumulator resulting in the short cycle time usage of hydraulic accumulators both in domestic and industrial purposes necessitates this research. The outcome of the research appears to be very efficient for generating fluctuation free electricity, power quality and reliability, energy saving/reutilization and system noise reduction.
All-metallic electrically gated 2H-TaSe2 thin-film switches and logic circuits
International Nuclear Information System (INIS)
We report the fabrication and performance of all-metallic three-terminal devices with tantalum diselenide thin-film conducting channels. For this proof-of-concept demonstration, the layers of 2H-TaSe2 were exfoliated mechanically from single crystals grown by the chemical vapor transport method. Devices with nanometer-scale thicknesses exhibit strongly non-linear current-voltage characteristics, unusual optical response, and electrical gating at room temperature. We have found that the drain-source current in thin-film 2H-TaSe2–Ti/Au devices reproducibly shows an abrupt transition from a highly resistive to a conductive state, with the threshold tunable via the gate voltage. Such current-voltage characteristics can be used, in principle, for implementing radiation-hard all-metallic logic circuits. These results may open new application space for thin films of van der Waals materials
Ground and CHAMP observations of field-aligned current circuits generated by lower atmospheric disturbances and expectations to the SWARM to clarify their three dimensional structure
Iyemori, Toshihiko; Nakanishi, Kunihito; Aoyama, Tadashi; Lühr, Hermann
Acoustic gravity waves propagated to the ionosphere cause dynamo currents in the ionosphere. They divert along geomagnetic field lines of force to another hemisphere accompanying electric field and then flow in the ionosphere of another hemisphere by the electric field forming closed current circuits. The oscillating current circuits with the period of acoustic waves generate magnetic variations on the ground, and they are observed as long period geomagnetic pulsations. This effect has been detected during big earthquakes, strong typhoons, tornados etc. On a low-altitude satellite orbit, the spatial distribution (i.e., structure) of the current circuits along the satellite orbit should be detected as temporal magnetic oscillations, and the effect is confirmed by a CHAMP data analysis. On the spatial structure, in particular, in the longitudinal direction, it has been difficult to examine by a single satellite or from ground magnetic observations. The SWARM satellites will provide an unique opportunity to clarify the three dimensional structure of the field-aligned current circuits.
Some Key Issues in Creating Inquiry-Based Instructional Practices that Aim at the Understanding of Simple Electric Circuits
Kock, Zeger-Jan; Taconis, Ruurd; Bolhuis, Sanneke; Gravemeijer, Koeno
Many students in secondary schools consider the sciences difficult and unattractive. This applies to physics in particular, a subject in which students attempt to learn and understand numerous theoretical concepts, often without much success. A case in point is the understanding of the concepts current, voltage and resistance in simple electric circuits. In response to these problems, reform initiatives in education strive for a change of the classroom culture, putting emphasis on more authentic contexts and student activities containing elements of inquiry. The challenge then becomes choosing and combining these elements in such a manner that they foster an understanding of theoretical concepts. In this article we reflect on data collected and analyzed from a series of 12 grade 9 physics lessons on simple electric circuits. Drawing from a theoretical framework based on individual (conceptual change based) and socio-cultural views on learning, instruction was designed addressing known conceptual problems and attempting to create a physics (research) culture in the classroom. As the success of the lessons was limited, the focus of the study became to understand which inherent characteristics of inquiry based instruction complicate the process of constructing conceptual understanding. From the analysis of the data collected during the enactment of the lessons three tensions emerged: the tension between open inquiry and student guidance, the tension between students developing their own ideas and getting to know accepted scientific theories, and the tension between fostering scientific interest as part of a scientific research culture and the task oriented school culture. An outlook will be given on the implications for science lessons.
Circular polarization of radio emission from air showers probes atmospheric electric fields in thunderclouds.
Gia Trinh, Thi Ngoc; Scholten, Olaf; Buitink, Stijn; Corstanje, Arthur; Ebert, Ute; Enriquez, Emilio; Falcke, Heino; Horandel, Jörg R.; Nelles, Anna; Schellart, Pim; Rachen, Jorg; Rossetto, Laura; Rutjes, Casper; ter Veen, Sander; Thoudam, Satyendra
When a high-energy cosmic-ray particle enters the upper layer of the atmosphere, it generates many secondary high-energy particles and forms a cosmic-ray-induced air shower. In the leading plasma of this shower electric currents are induced that emit electromagnetic radiation. These radio waves can be detected with LOw-Frequency ARray (LOFAR) radio telescope. Events have been collected under fair-weather conditions as well as under atmospheric conditions where thunderstorms occur. For the events under the fair weather conditions the emission process is well understood by present models. For the events measured under the thunderstorm conditions, we observe a large fraction of the circular polarization near the core of the shower which is not shown in the events under the fair-weather conditions. This can be explained by the change of direction of the atmospheric electric fields with altitude. Therefore, measuring the circular polarization of radio emission from cosmic ray extensive air showers during the thunderstorm conditions helps to have a better understanding about the structure of atmospheric electric fields in the thunderclouds.
Effects of the March 2015 solar eclipse on near-surface atmospheric electricity.
Bennett, A J
Measurements of atmospheric electrical and standard meteorological parameters were made at coastal and inland sites in southern England during the 20 March 2015 partial solar eclipse. Clear evidence of a reduction in air temperature resulting from the eclipse was found at both locations, despite one of them being overcast during the entire eclipse. The reduction in temperature was expected to affect the near-surface electric field (potential gradient (PG)) through a reduction in turbulent transfer of space charge. No such effect could be unambiguously confirmed, however, with variability in PG and air-Earth current during the eclipse being comparable to pre- and post-eclipse conditions. The already low solar radiation for this latitude, season and time of day was likely to have contributed to the reduced effect of the eclipse on atmospheric electricity through boundary layer stability. The absence of a reduction in mean PG shortly after time of maximum solar obscuration, as observed during eclipses at lower geomagnetic latitude, implied that there was no significant change in atmospheric ionization from cosmic rays above background variability. This finding was suggested to be due to the relative importance of cosmic rays of solar and galactic origin at geomagnetic mid-latitudes.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'. PMID:27550771
High School Students' Understanding of Resistance in Simple Series Electric Circuits.
Liegeois, Laurent; Mullet, Etienne
Studies the understanding that 8-12 grade high school students were able to develop with regard to the interrelationships between resistance, potential difference, and current concepts (Ohm's law). Explores the immediate effects of exposure to electricity courses on the intuitive mastery of these relationships. (Contains 32 references.)…
Work in progress-role of learning strategies in electrical circuits and analog electronics courses
Ramírez Echeverry, Jhon Jairo; Olarte Dussan, Fredy Andres; García Carrillo, Àgueda
This work-in-progress describes a study intended to determine whether self-regulated learning strategies influence the academic performance of students from the Department of Electrical and Electronics Engineering at Universidad Nacional de Colombia. This research was conducted with 396 students in two terms, who were surveyed about their use of learning strategies using the CEAM II psychometric tool. Later, it was analyzed whether a significant correlation exists between the scores obtained ...
Theoretical Computation for Non-Equilibrium Air Plasma Electrical Conductivity at Atmospheric Pressure
Institute of Scientific and Technical Information of China (English)
HAN Dong; GUO Wen-Kang; XU Ping; LIANG Rong-Qing
@@ Based on the Chapman-Enskog theory, we calculate the electrical conductivity of non-equilibrium air plasma in the two-temperature model. We consider different degrees of non-equilibrium, which is defined by the ratio of electronic temperature to heavy particles temperature. The method of computing the composition of air plasma is demonstrated. After calculating the electrical conductivity from electron temperature 1000 K to 15000K, the present result is compared with Murphy's study [Plasma Chem. Plasma Process 15 (1994) 279] for equilibrium case. All the calculation is completed at atmospheric pressure. The present results may have potential applications in numerical calculation of non-equilibrium air plasma.
The Effect of the Disturbed Electric Field of the Atmosphere on Cosmic Rays 2. Hard Component
Khaerdinov, S; Petkov, B
The results of studying the correlation of the hard component of cosmic rays with the electric field of the atmosphere during thunderstorm periods are presented. The data at several energy thresholds are examined using the liquid scintillators of the the Baksan air shower array and the plastic scintillators of the muon detector with a threshold of 1 GeV. It is demonstrated that the quadratic effect (changing intensity of muons at the electric field of any sign) is the most pronounced for soft muons.
The Effect of the Disturbed Electric Field of the Atmosphere on Cosmic Rays 1. Soft Component
Khaerdinov, S; Petkov, B; Surovetsky, Yu
The results of studying the correlation of the soft component of cosmic rays (10-30 MeV) with the electric field of the atmosphere during thunderstorm periods are presented. The uncovered scintillators of the Baksan air shower array are used as detectors of the soft component, and the data for three seasons (2000--2002) are included into the analysis. It is shown that both linear and quadratic effects of the electric field are present in the soft component intensity. In this case, the linear term is rather stable and independent of the selection criteria, while the quadratic term is subject to significant variations.
Evaluation of atmospheric corrosion on electroplated zinc and zinc nickel coatings by Electrical Resistance (ER) Monitoring
DEFF Research Database (Denmark)
Møller, Per
ER (Electrical Resistance) probes provide a measurement of metal loss, measured at any time when a metal is exposed to the real environment. The precise electrical resistance monitoring system can evaluate the corrosion to the level of nanometers, if the conductivity is compensated for temperature...... and magnetic fields. With this technique very important information about the durability of a new conversion coatings for aluminum, zinc and zinc alloys exposed to unknown atmospheric conditions can be gathered. This is expected to have a major impact on a number of industrial segments, such as test cars...
Design and construction of prototype transversely excited atmospheric (TEA nitrogen laser energized by a high voltage electrical discharge
Directory of Open Access Journals (Sweden)
Mukhtar Hussain
Full Text Available The present study reports design and construction, of a prototype of Transversely Excited Atmospheric (TEA nitrogen laser, and a high voltage power supply to excite N2 gas in air, while air is used as an active lasing medium. A Blumlein line discharge circuit is used for operation of this laser. The high voltage is generated by a fly back transformer based power supply varying from 10 kV to 20 kV. The wavelength (337.1 nm of TEA nitrogen laser is measured employing a standard commercial spectrometer and the laser output energy of 300 μJ is measured from the constructed system. Different parameters such as beam profile, laser output spectrum, laser efficiency, and variation of E/P (Electrical field/Pressure value with respect to input voltage and electrodes separations are studied in order to optimize the overall operational efficiency of present nitrogen laser. The analysis of the high voltage prototype appeared in this designed source has also been made and described in this paper.
Analogy for Drude's Free Electron Model to Promote Students' Understanding of Electric Circuits in Lower Secondary School
de Almeida, Maria José B. M.; Salvador, Andreia; Costa, Maria Margarida R. R.
Aiming at a deep understanding of some basic concepts of electric circuits in lower secondary schools, this work introduces an analogy between the behavior of children playing in a school yard with a central lake, subject to different conditions, rules, and stimuli, and Drude's free electron model of metals. Using this analogy from the first…
The Effects on Students' Conceptual Understanding of Electric Circuits of Introducing Virtual Manipulatives within a Physical Manipulatives-Oriented Curriculum
Zacharia, Zacharias C.; de Jong, Ton
This study investigates whether Virtual Manipulatives (VM) within a Physical Manipulatives (PM)-oriented curriculum affect conceptual understanding of electric circuits and related experimentation processes. A pre-post comparison study randomly assigned 194 undergraduates in an introductory physics course to one of five conditions: three…
Military Curricula for Vocational & Technical Education. Basic Electricity and Electronics Individualized Learning System. CANTRAC A-100-0010. Module Six: Parallel Circuits. Study Booklet.
Chief of Naval Education and Training Support, Pensacola, FL.
This individualized learning module on parallel circuits is one in a series of modules for a course in basic electricity and electronics. The course is one of a number of military-developed curriculum packages selected for adaptation to vocational instructional and curriculum development in a civilian setting. Four lessons are included in the…
Military Curricula for Vocational & Technical Education. Basic Electricity and Electronics Individualized Learning System. CANTRAC A-100-0010. Module Fourteen: Parallel AC Resistive-Reactive Circuits. Study Booklet.
Chief of Naval Education and Training Support, Pensacola, FL.
This individualized learning module on parallel alternating current resistive-reaction circuits is one in a series of modules for a course in basic electricity and electronics. The course is one of a number of military-developed curriculum packages selected for adaptation to vocational instructional and curriculum development in a civilian…
Directory of Open Access Journals (Sweden)
P. E. Mihalichenko
Full Text Available The article deals with the description of mathematical model of the system of traction electric power supply with load in the short circuit condition as well as the calculation results of this emergency process. The transition values as well as the character of their change, which can be used for detection of emergency processes, have been determined.
Military Curricula for Vocational & Technical Education. Basic Electricity and Electronics. CANTRAC A-100-0010. Module 34: Linear Integrated Circuits. Study Booklet.
Chief of Naval Education and Training Support, Pensacola, FL.
This individualized learning module on linear integrated circuits is one in a series of modules for a course in basic electricity and electronics. The course is one of a number of military-developed curriculum packages selected for adaptation to vocational instructional and curriculum development in a civilian setting. Two lessons are included in…
Magnetic circuit of a contactless torque sensor for electric power steering
Fröhlich, Ekkehart; Jerems, Frank
Modern passenger cars are increasingly equipped with electromechanical steering assist rather than hydraulic systems known for many decades. Major benefits are reduced fuel consumption (up to 0.2l/100 km) and increased functionality. As such a system reacts to the drivers input in terms of steering torque or steering effort, a sensor is required that accurately measures the steering torque. Valeo has adopted a magnetic technology and has improved the performance by adding specially designed flux concentration devices. The magnetic circuit consists of a multi-pole ring magnet and a pair of ring-shaped soft magnetic parts rotating together with the steering shaft and an additional pair of soft magnetic flux concentration devices which are fixed stationary inside the housing. The steering torque causes a relative twist between magnet and the soft magnetic rings, therefore implementing a proportional magnetisation of the latter. A U-shape was chosen for the flux concentration devices in order to compensate mechanical tolerances of the system. The main focus of this paper will be on the tolerance behaviour of the sensor system and the impact of the flux concentration devices. Because of the nonlinear nature of the magnetisation curve of the NiFe alloy used extensive 3D FEM simulation was necessary. Simulation enables us to have a look inside the soft magnetic material and predict the spatial magnetisation distribution with the benefit of avoiding saturation. The result is an optimised sensor, which meets both the harsh environmental conditions inside the motor compartment as well as the cost pressure in the automotive business.
Specific variations of the atmospheric electric field potential gradient as a possible precursor of Caucasus earthquakes
Directory of Open Access Journals (Sweden)
N. Kachakhidze
Full Text Available The subject of the research is the study of anomalous disturbances of the gradient of electric field potential of the atmosphere as possible precursors of earthquakes.
In order to reveal such precursor Dusheti observatory (φ=42.05; λ=44.42 records of electric field potential's gradient (EFPG of the atmosphere are considered for 41 earthquakes (M≥5.0 occurrence moments in the Caucasus region.
Seasonal variations of atmospheric electric field potential gradient and inter overlapping influence of meteorological parameters upon this parameter are studied. Original method of "filtration" is devised and used in order to identify the effect of EFPG "clear" anomalies.
The so-called "clear" anomalies are revealed from (−148.9 V/m to 188.5 V/m limits and they are connected with occurrence moments of 29 earthquakes out of 41 discussed earthquakes (about 71%. "clear" anomalies manifest themselves in 11-day precursor window.
Duration of anomalies is from 40 to 90 min.
Ambipolar Electric Field, Photoelectrons, and Their Role in Atmospheric Escape From Hot Jupiters
Cohen, O.; Glocer, A.
Atmospheric mass loss from Hot Jupiters can be large due to the close proximity of these planets to their host star and the strong radiation the planetary atmosphere receives. On Earth, a major contribution to the acceleration of atmospheric ions comes from the vertical separation of ions and electrons, and the generation of the ambipolar electric field. This process, known as the "polar wind," is responsible for the transport of ionospheric constituents to Earth's magnetosphere, where they are well observed. The polar wind can also be enhanced by a relatively small fraction of super-thermal electrons (photoelectrons) generated by photoionization.We formulate a simplified calculation of the effect of the ambipolar electric field and the photoelectrons on the ion scale height in a generalized manner. We find that the ion scale height can be increased by a factor of 2-15 due to the polar wind effects. We also estimate a lower limit of an order of magnitude increase of the ion density and the atmospheric mass-loss rate when polar wind effects are included.
Atmospheric electrification in the Solar System
Aplin, K
Atmospheric electrification is not a purely terrestrial phenomenon: all Solar System planetary atmospheres become slightly electrified by cosmic ray ionisation. There is evidence for lightning on Jupiter, Saturn, Uranus and Neptune, and it appears likely to exist on Mars, Venus and Titan. Atmospheric electricity has controversially been implicated in climate on Earth; here, a comparative approach is employed to review the role of electrification in the atmospheres of other planets and their moons. This paper reviews planetary atmospheric electricity including ionisation and ion-aerosol interactions. The conditions necessary for a global electric circuit, and the likelihood of meeting these conditions in other planetary atmospheres are briefly discussed. Atmospheric electrification could be important throughout the Solar System, particularly at the outer planets which receive little solar radiation, increasing the significance of electrical forces. Nucleation onto atmospheric ions has been predicted to affect ...
Electric fields, electron precipitation, and VLF radiation during a simultaneous magnetospheric substorm and atmospheric thunderstorm
International Nuclear Information System (INIS)
A balloon payload instrumented with a double-probe electric field detector and an X ray scintillation counter was launched from Roberval, Quebec, Canada (L=4.1) at 0828 UT (0328 LT) on July 9, 1975. A magnetospheric substorm was observed locally between 0815 and 1100 UT, which produced a maximum ΔB of approx.500 nT at approx.0930 UT. A single-cell atmospheric thunderstorm developed northeast of Roberval beginning around 0925 UT which was most intense from approx.1000 to 1035 UT. Detailed study of the electrical properties of the thunderstorm, the X ray precipitation data, and VLF spheric data leads to three conclusions. First, the electrical coupling from the thunderstorm to the magnetosphere increases with frequency from dc to the VLF; for the observed storm the amplitude at the ionosphere of thunderstorm produced electric fields was not significant at frequencies below 0.1 Hz. Second, the atmospheric conductivity above the thunderstorm was observed to be about one-half the fair weather value prior to 1000 UT; decreased to about one-quarter the fair weather value at about 1000 UT; and remained depressed after the end of the thunderstorm. This result was contrary to that expected on the basis of previous work and is one which merits considerably more investigation. Third, the data show a high probability that half-hop whistlers initiated by sferics from the thunderstorm triggered energetic electron precipitation from the magnetosphere
Sub-nanosecond dynamics of atmospheric air discharge under highly inhomogeneous and transient electric field
Tardiveau, Pierre; Magne, Lionel; Pasquiers, Stephane; Jeanney, Pascal; Bournonville, Blandine
The effects of the application of extreme overvoltages (>500%) in air gaps over less than a few nanoseconds bring us to reconsider the classical physics of streamer used to describe air discharges at atmospheric pressure. Non equilibrium discharges created by extremely transient and intense electric fields in standard conditions of pressure and temperature exhibit unusual diffuse and large structure. In point-to-plane electrode configurations, a plasma cloud is observed which properties depend on voltage pulses features (amplitude, rise time, length, and frequency) and electrodes properties (material, shape, and gap length). Our parametric experimental study is based on fast electrical characterization and sub-nanosecond imaging and shows the different stages of propagation of the cloud. This work details the conditions to maximize the cloud size without moving towards a multi-channel streamer regime. Based on the analysis and the Abel transform processing of the emission of excited states of nitrogen from the discharge, a focus is made on the structuration of the plasma cloud while it is propagating. It shows how much, according to the experimental conditions, the external electric field can be screened by the plasma and, inversely, how deep and how long a high electric field can be sustained in the gap, that is challenging for pulsed atmospheric plasmas applications. This work benefits from the financial support of the National Agency of Research within the framework of the project ANR-13-BS09-0014.
Simulation of radio emission from air showers in atmospheric electric fields
Buitink, S; Falcke, H; Kuijpers, J
We study the effect of atmospheric electric fields on the radio pulse emitted by cosmic ray air showers. Under fair weather conditions the dominant part of the radio emission is driven by the geomagnetic field. When the shower charges are accelerated and deflected in an electric field additional radiation is emitted. We simulate this effect with the Monte Carlo code REAS2, using CORSIKA-simulated showers as input. In both codes a routine has been implemented that treats the effect of the electric field on the shower particles. We find that the radio pulse is significantly altered in background fields of the order of ~100 V/cm and higher. Practically, this means that air showers passing through thunderstorms emit radio pulses that are not a reliable measure for the shower energy. Under other weather circumstances significant electric field effects are expected to occur rarely, but nimbostratus clouds can harbor fields that are large enough. In general, the contribution of the electric field to the radio pulse ...
Twelve years of continuous measurements of atmospheric electrical activity in Mexico's Tropical highland
Energy Technology Data Exchange (ETDEWEB)
Troncoso Lozada, O. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico (UNAM), Mexico, D.F. (Mexico)
Atmospheric electric activity measurements have been recorded continuously by a punctual lightning system at a tropical highland observatory from 1988 onwards, and were analyzed to obtain lightning statistical confident results for thunderstorms occurrence on the leeward side of the southern mountain ridge of Mexico's Valley. Shown, as examples, are individual profiles of the atmospheric electrical activity, associated with severe storms. The results make clear that the fastest possible sequence of electrical measurements is required to obtain significant and applications oriented data in connection with a whole series of thunderstorms taking into account the mean time variation of the atmospheric electricity measurements at an altitude of 2270 m a.s.l. The seasonal variation indicates that the lightning flash peak currents were found to be larger in summer with less than 10% occurring in the autumn and winter. With rainfall data from a network of 66 stations, we obtained a significant correlation with the lightning frequency. Special attention was undertaken concerning the question of the atmospheric electrical activity and climate at Valley of Mexico. [Spanish] Se midieron ininterrumpidamente las variaciones de la actividad electrica en la atmosfera, de enero de 1988 a diciembre de 1999, en un observatorio de altura (2,250 m s.n.m.), y se analizaron para obtener resultados estadisticos confiables con relacion a la ocurrencia de tormentas en la region sur del Valle de Mexico. Como ejemplos, se muestran los perfiles individuales de la actividad electrica atmosferica asociada con tormentas severas. Los resultados dejan claro que se requiere de la secuencia de medidas electricas lo mas rapida posible para obtener datos significativos y aplicables en relacion con una serie completa de tormentas, considerando la media del tiempo de variacion de las mediciones de la actividad electrica atmosferica a una altitud de 2,270 m s.n.m. La validacion estacional indica que
An examination of AC/HVDC power circuits for interconnecting bulk wind generation with the electric grid
Energy Technology Data Exchange (ETDEWEB)
Ludois, D.; Venkataramanan, G. [Department of Electrical and Computer Engineering, University of Wisconsin-Madison 1415 Engineering Dr. Madison WI 53706 (United States)
The application of high voltage DC (HVDC) transmission for integrating large scale and/or off-shore wind generation systems with the electric grid is attractive in comparison to extra high voltage (EHV) AC transmission due to a variety of reasons. While the technology of classical current sourced converters (CSC) using thyristors is well established for realization of large HVDC systems, the technology of voltage sourced converters (VSC) is emerging to be an alternative approach, particularly suitable for multi-terminal interconnections. More recently, a more modular scheme that may be termed 'bridge of bridge' converters (BoBC) has been introduced to realize HVDC systems. While all these three approaches are functionally capable of realizing HVDC systems, the converter power circuit design trade-offs between these alternatives are not readily apparent. This paper presents an examination of these topologies from the point of view of power semiconductor requirements, reactive component requirements, operating losses, fault tolerance, multi-terminal operation, modularity, complexity, etc. Detailed analytical models will be used along with a benchmark application to develop a comparative evaluation of the alternatives that may be used by wind energy/bulk transmission developers for performing engineering trade-off studies. (author)
An Examination of AC/HVDC Power Circuits for Interconnecting Bulk Wind Generation with the Electric Grid
Directory of Open Access Journals (Sweden)
Daniel Ludois
Full Text Available The application of high voltage dc (HVDC transmission for integrating large scale and/or off-shore wind generation systems with the electric grid is attractive in comparison to extra high voltage (EHV ac transmission due to a variety of reasons. While the technology of classical current sourced converters (CSC using thyristors is well established for realization of large HVDC systems, the technology of voltage sourced converters (VSC is emerging to be an alternative approach, particularly suitable for multi-terminal interconnections. More recently, a more modular scheme that may be termed 'bridge of bridge' converters (BoBC has been introduced to realize HVDC systems. While all these three approaches are functionally capable of realizing HVDC systems, the converter power circuit design trade-offs between these alternatives are not readily apparent. This paper presents an examination of these topologies from the point of view of power semiconductor requirements, reactive component requirements, operating losses, fault tolerance, multi-terminal operation, modularity, complexity, etc. Detailed analytical models will be used along with a benchmark application to develop a comparative evaluation of the alternatives that maybe used by wind energy/bulk transmission developers for performing engineering trade-off studies.
Long-Term Characterization of 6H-SiC Transistor Integrated Circuit Technology Operating at 500 C
Neudeck, Philip G.; Spry, David J.; Chen, Liang-Yu; Chang, Carl W.; Beheim, Glenn M.; Okojie, Robert S.; Evans, Laura J.; Meredith Roger D.; Ferrier, Terry L.; Krasowski, Michael J.; Prokop, Norman F.
NASA has been developing very high temperature semiconductor integrated circuits for use in the hot sections of aircraft engines and for Venus exploration. This paper reports on long-term 500 C electrical operation of prototype 6H-SiC integrated circuits based on epitaxial 6H-SiC junction field effect transistors (JFETs). As of this writing, some devices have surpassed 4000 hours of continuous 500 C electrical operation in oxidizing air atmosphere with minimal change in relevant electrical parameters.
Predicted electrical conductivity between 0 and 80 km in the Venusian atmosphere
Borucki, W. J.; Levin, Z.; Whitten, R. C.; Keesee, R. G.; Capone, L. A.; Toon, O. B.; Dubach, J.
Calculations of the space charge, ion density, and conductivity in the Venus atmosphere were made. The presence of the cloud particles on Venus causes a profund reduction in the calculated values of the ion density and conductivity compared to the values that are obtained without consideration of the cloud particles. When the cloud particles are included in the calculations, the results for the ion density and conductivity are approximately the same as those of the terrestrial atmosphere at the same pressure-altitude. Because the particles span such a large range of sizes and are abundant over a substantial range of pressure, the space charge varies strongly with altitude and particle size. Differential settling of the particles is expected to produce weak electric fields in the clouds.
Electrical properties of metallic SmS phase stable at atmospheric pressure
International Nuclear Information System (INIS)
The electric conductivity, Hall effect and magnetoresistance of SmS metal phase, stable at atmospheric pressu re, produced by transformation of a thin polycrystalline semiconductor film to a metal state over the whole thickness with the use of mechanical polishing were investigated. The temperature of measurements ranged within 0.45 to 260 K. It is established from the behaviour of the Hall constant and Hall mobility that a metal film corresponds to a high pressure phase of SmS metal monocrystals. The concentration of conductivity electrons in the film at helium temperatures corresponds to 2.80 samarium ion valency
Relationship Between Aerosol Number Size Distribution and Atmospheric Electric Potential Gradient in an Urban Area
Wright, Matthew; Matthews, James; Bacak, Asan; Silva, Hugo; Priestley, Michael; Percival, Carl; Shallcross, Dudley
Small ions are created in the atmosphere by ground based radioactive decay and solar and cosmic radiation ionising the air. The ionosphere is maintained at a high potential relative to the Earth due to global thunderstorm activity, a current from the ionosphere transfers charge back to the ground through the weakly ionised atmosphere. A potential gradient (PG) exists between the ionosphere and the ground that can be measured in fair weather using devices such as an electric field mill. PG is inversely-proportional to the conductivity of the air and therefore to the number of ions of a given electrical mobility; a reduction of air ions will cause an increase of PG. Aerosols in the atmosphere act as a sink of air ions with an attachment rate dependent on aerosol size distribution and ion mobility. These relationships have been used to infer high particulate, and hence pollution, levels in historic datasets of atmospheric PG. A measurement campaign was undertaken in Manchester, UK for three weeks in July and August where atmospheric PG was measured with an electric field mill (JCI131, JCI Chilworth) on a second floor balcony, aerosol size distribution measured with a scanning mobility particle sizer (SMPS, TSI3936), aerosol concentration measured with a condensation particle counter (CPC, Grimm 5.403) and local meteorological measurements taken on a rooftop measurement site ~200 m away. Field mill and CPC data were taken at 1 s intervals and SMPS data in 2.5 minute cycles. Data were excluded for one hour either side of rainfall as rainclouds and droplets can carry significant charge which would affect PG. A quantity relating to the attachment of ions to aerosol (Ion Sink) was derived from the effective attachment coefficient of the aerosols. Further measurements with the field mill and CPC were taken at the same location in November 2015 when bonfire events would be expected to increase aerosol concentrations. During the summer measurements, particle number count (PNC
Measurements of atmospheric electrical parameters and ELF electromagnetic emissions during a meteorological balloon flight.
Benda, Robert; Dujany, Matthieu; Berthomieu, Roland; Boissier, Mathilde; Bruneel, Pierre; Fischer, Lucie; Focillon, William; Gullo, Robin; Hubert, Valentin; Lafforgue, Gaétan; Loe-Mie, Marichka; Messager, Adrien; Roy, Felix; Auvray, Gérard; Bertrand, Fabrice; Coulomb, Romain; Deprez, Gregoire; Berthelier, Jean-Jacques
Measurements of electric field and atmospheric conductivity were performed onboard a small payload flown under a meteorological balloon during a fair weather period. This experiment is part of a project to study thunderstorms and TLE organized in the frame of the engineering cursus at Ecole Polytechnique. The payload is equipped with 4 electrodes to measure the 3 components of the DC and AC electric fields up to 3.2 kHz. Dedicated sequences of operation, when one electrode is operated in the relaxation mode, have been used to determine the positive and negative electrical conductivities. Altitude profiles of the DC vertical electric field and conductivities in agreement with expected fair weather parameters were obtained from ~ 3.5 to ~ 13 km before the failure of a battery. At an altitude of ~ 9 km slight disturbances in the electric field suggest the traversal of thin clouds with disturbed electrical characteristics. Schumann resonances were observed up to the fifth harmonics at levels that are typical of a quiet period over Europe with most thunderstorms located over remote longitudinal sectors. EM waves due the power lines at 50Hz are detected during the whole measuring period and their altitude and horizontal variations will be presented as a function of the position of the balloon over the ground power network. A surprising and interesting observation was made of a Russian transmitter at 82 Hz located in Murmansk region and used for sub-marine communications. We shall present an initial analysis of the amplitude and polarization of the corresponding signal.
Electric field development in γ-mode radiofrequency atmospheric pressure glow discharge in helium
Navrátil, Zdeněk; Josepson, Raavo; Cvetanović, Nikola; Obradović, Bratislav; Dvořák, Pavel
Time development of electric field strength during radio-frequency sheath formation was measured using Stark polarization spectroscopy in a helium γ-mode radio-frequency (RF, 13.56 MHz) atmospheric pressure glow discharge at high current density (3 A cm-2). A method of time-correlated single photon counting was applied to record the temporal development of spectral profile of He I 492.2 nm line with a sub-nanosecond temporal resolution. By fitting the measured profile of the line with a combination of pseudo-Voigt profiles for forbidden (2 1P-4 1F) and allowed (2 1P-4 1D) helium lines, instantaneous electric fields up to 32 kV cm-1 were measured in the RF sheath. The measured electric field is in agreement with the spatially averaged value of 40 kV cm-1 estimated from homogeneous charge density RF sheath model. The observed rectangular waveform of the electric field time development is attributed to increased sheath conductivity by the strong electron avalanches occurring in the γ-mode sheath at high current densities.
1D Modeling of a Bifacial Silicon Solar Cell under Frequency Modulation Monochromatic Illumination: Determination of the Equivalent Electrical Circuit Related to the Surface Recombination Velocity
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H. Ly Diallo
Full Text Available We present in this study the determination of the equivalent electrical circuits associated to the recombination velocities for a bifacial silicon solar cell under frequency modulation and monochromatic illumination. This determination is based on Bode and Nyquist diagrams that is the variations of the phase and the module of the back surface and intrinsic junction recombination velocities. Their dependence on illumination wavelength is also shown.
Influences of cosmic radiation, artificial radioactivity and aerosol concentration upon the fair-weather atmospheric electric field in Lisbon (1955–1991)
Serrano, Claudia; Reis, A. Heitor; Rosa, Rui; P. S. Lucio
The atmospheric electric field is influenced by cosmic radiation, radioactivity and aerosols. In this work we investigate the existence of: (i) correlations between relative anomalies of annual values of atmospheric electric field and cosmic radiation intensity, artificial radioactivity and aerosol concentration; (ii) seasonal correlations between relative anomalies of the atmospheric electric field and cosmic radiation intensity. We used data of the electric field strength recorded at the Po...
Nonzero Temperature Squeezing of the Time-Dependent Harmonic Oscillator and the Applications to the Capacitive Coupled Electric Circuit
Institute of Scientific and Technical Information of China (English)
LIANG Mai-Lin; YUAN Bing
A new way to calculate the nonzero temperature quantum fluctuations of the time-dependent harmonicoscillator is proposed and the properties of squeezing are exactly given. The method is applied to the capacitive coupledelectric circuit. It is explicitly shown that squeezing can appear and the squeezing parameters are related to the physicalquantities of the coupled circuit.
Lithium Ion Batteries—Development of Advanced Electrical Equivalent Circuit Models for Nickel Manganese Cobalt Lithium-Ion
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Alexandros Nikolian
Full Text Available In this paper, advanced equivalent circuit models (ECMs were developed to model large format and high energy nickel manganese cobalt (NMC lithium-ion 20 Ah battery cells. Different temperatures conditions, cell characterization test (Normal and Advanced Tests, ECM topologies (1st and 2nd Order Thévenin model, state of charge (SoC estimation techniques (Coulomb counting and extended Kalman filtering and validation profiles (dynamic discharge pulse test (DDPT and world harmonized light vehicle profiles have been incorporated in the analysis. A concise state-of-the-art of different lithium-ion battery models existing in the academia and industry is presented providing information about model classification and information about electrical models. Moreover, an overview of the different steps and information needed to be able to create an ECM model is provided. A comparison between begin of life (BoL and aged (95%, 90% state of health ECM parameters (internal resistance (Ro, polarization resistance (Rp, activation resistance (Rp2 and time constants (τ is presented. By comparing the BoL to the aged parameters an overview of the behavior of the parameters is introduced and provides the appropriate platform for future research in electrical modeling of battery cells covering the ageing aspect. Based on the BoL parameters 1st and 2nd order models were developed for a range of temperatures (15 °C, 25 °C, 35 °C, 45 °C. The highest impact to the accuracy of the model (validation results is the temperature condition that the model was developed. The 1st and 2nd order Thévenin models and the change from normal to advanced characterization datasets, while they affect the accuracy of the model they mostly help in dealing with high and low SoC linearity problems. The 2nd order Thévenin model with advanced characterization parameters and extended Kalman filtering SoC estimation technique is the most efficient and dynamically correct ECM model developed.
Control of the Earth's electric field intensity through solar wind modulation of galactic cosmic radiation: Support for a proposed atmospheric electrical sun-weather mechanism
Markson, R.
The ionospheric potential and galactic cosmic radiation, found to be inversely correlated with the solar wind velocity are examined as being germane to weather modification. Since the ionospheric potential is proportional to the fair weather electric field intensity and cosmic radiation is the dominant source of atmospheric ionization, it is concluded that the Earth's overall electric field varies in phase with atmospheric ionization and that the latter is modulated by the solar wind. A proposed mechanism, in which solar control of ionizing radiation influences atmospheric electrification and thus possibly cloud physical processes is discussed. An experimental approach to critically test the proposed mechanism through comparison of the temporal variation of the Earth's electric field with conditions in the interplanetary medium is outlined.
Resistor Combinations for Parallel Circuits.
McTernan, James P.
To help simplify both teaching and learning of parallel circuits, a high school electricity/electronics teacher presents and illustrates the use of tables of values for parallel resistive circuits in which total resistances are whole numbers. (MF)
Automatic System for the D.C. High Voltage Qualification of the Superconducting Electrical Circuits of the LHC Machine
Bozzini, D; Russenschuck, Stephan; Bednarek, M; Jurkiewicz, P; Kotarba, A; Ludwin, J; Olek, S
A d.c. high voltage test system has been developed to verify automatically the insulation resistance of the powering circuits of the LHC. In the most complex case, up to 72 circuits share the same volume inside cryogenic lines. Each circuit can have an insulation fault versus any other circuit or versus ground. The system is able to connect up to 80 circuits and apply a voltage up to 2 kV D.C. The leakage current flowing through each circuit is measured within a range of 1 nA to 1.6 mA. The matrix of measurements allows characterizing the paths taken by the currents and locating weak points of the insulation between circuits. The system is composed of a D.C. voltage source and a data acquisition card. The card is able to measure with precision currents and voltages and to drive up to 5 high voltage switching modules offering 16 channels each. A LabVIEW application controls the system for an automatic and safe operation. This paper describes the hardware and software design, the testing methodology and the res...
Diurnal variations of 218Po, 214Pb, and 214Po and their effect on atmospheric electrical conductivity in the lower atmosphere at Mysore
International Nuclear Information System (INIS)
The short-lived radon daughters (218Po, 214Pb, 214Bi and 214Po) are natural tracers in the troposphere in particular near the ground surface. They are electrically charged particles and are chemically reactive. As soon as they are formed they get attached to the aerosol particles of the atmosphere. Their behaviour is similar to that of aerosols with respect to their growth, transport, removal processes in the atmosphere. The electrical conductivity of the atmosphere is mainly due to the presence of highly mobile (small) ions. Hence the electrical conductivity of air at near the surface of the earth mainly due to 222Rn, 218Po, 214Pb, 214Bi and 214Po concentrations, and depends on aerosol concentrations and meteorological parameters. The individual radon progeny concentrations (218Po, 214Pb, and 214Po) are measured using Air Flow meter. The concentration of radon in the atmospheric air is measured using Low Level Radon Detection System. The total energy released due to both radon and its progeny is computed in energy units (eV cm-3s-1) and is converted into ion-pair production rate (No. cm-3 s-1), 32 eV being the energy producing one-ion pair. The atmospheric electrical conductivity (both positive and negative) is measured using a Gerdien's apparatus with two identical tubes. The average values of 218Po, 214Pb, and 214Po are respectively 13.70, 1.45 and 1.92 Bq m-3 respectively. The average value of positive and negative electrical conductivity are 5.08 x 10-14U-1 m-1 and 4.67 x 10-14 U-1 m-1. The concentrations of radon, its progeny, and positive and negative conductivity show a similar kind of diurnal variations with maximum in the early morning hours and a minimum during day time. The activity is higher in winter than in summer and rainy season. (author)
Helium atmospheric pressure plasma jets interacting with wet cells: delivery of electric fields
Norberg, Seth A.; Johnsen, Eric; Kushner, Mark J.
The use of atmospheric pressure plasma jets (APPJs) in plasma medicine have produced encouraging results in wound treatment, surface sterilization, deactivation of bacteria, and treatment of cancer cells. It is known that many of the reactive oxygen and nitrogen species produced by the APPJ are critical to these processes. Other key components to treatment include the ion and photon fluxes, and the electric fields produced in cells by the ionization wave of the APPJ striking in the vicinity of the cells. These relationships are often complicated by the cells being covered by a thin liquid layer—wet cells. In this paper, results from a computational investigation of the interaction of APPJs with tissue beneath a liquid layer are discussed. The emphasis of this study is the delivery of electric fields by an APPJ sustained in He/O2 = 99.8/0.2 flowing into humid air to cells lying beneath water with thickness of 200 μm. The water layer represents the biological fluid typically covering tissue during treatment. Three voltages were analyzed—two that produce a plasma effluent that touches the surface of the water layer and one that does not touch. The effect of the liquid layer thickness, 50 μm to 1 mm, was also examined. Comparisons were made of the predicted intracellular electric fields to those thresholds used in the field of bioelectronics.
A tomographic visualization of electric discharge sound fields in atmospheric pressure plasma using laser diffraction
Nakamiya, Toshiyuki; Mitsugi, Fumiaki; Iwasaki, Yoichiro; Ikegami, Tomoaki; Tsuda, Ryoichi; Sonoda, Yoshito; Danuta Stryczewska, Henryka
The phase modulation of transparent gas can be detected using Fraunhofer diffraction technique, which we call optical wave microphone (OWM). The OWM is suitable for the detection of sonic wave from audible sound to ultrasonic wave. Because this technique has no influence on sound field or electric field during the measurement, we have applied it to the sound detection for the electric discharges. There is almost no research paper that uses the discharge sound to examine the electrical discharge phenomenon. Two-dimensional visualization of the sound field using the OWM is also possible when the computerized tomography (CT) is combined. In this work, coplanar dielectric barrier discharge sin different gases of Ar, N2, He were characterized via the OWM as well as applied voltage and discharge current. This is the first report to investigate the influence of the type of the atmospheric gas on the two-dimensional sound field distribution for the coplanar dielectric barrier discharge using the OWM with CT. Contribution to the Topical Issue "13th International Symposium on High Pressure Low Temperature Plasma Chemistry (Hakone XIII)", Edited by Nicolas Gherardi, Henryca Danuta Stryczewska and Yvan Ségui.
A mechanistic study of initial atmospheric corrosion kinetics using electrical resistance sensors
International Nuclear Information System (INIS)
This paper describes a novel experimental approach to the study of atmospheric corrosion of iron and zinc, utilising electrical resistance sensors that are sensitive to corrosion losses of the order of one atomic monolayer. Using such devices, a mechanistic study of the initial stages in the atmospheric corrosion of iron and zinc was performed in a rectangular flow cell using controlled relative humidity (RH), temperature and gas flow rate. Additionally, the effects of SO2 contamination in the gas phase and prior NaCl contamination of the metal surface were studied. It was found that the initial corrosion kinetics of iron and zinc are, not unexpectedly, dominated by the development of surface corrosion product films, but that the growth kinetics vary with metal, humidity, etc. Specifically, in the presence of gas-phase SO2, activation energies and kinetic and chemical rate orders were consistent with control of the atmospheric corrosion process by solution-phase oxidation of sulphite-sulphate ion. For iron, this implies that the well-known sulphate-nest theory is inoperative at least during the early stages of atmospheric corrosion. In contrast, for chloride-contaminated zinc, the data were consistent with a rate-controlled diffusion of a species, probably water vapour or oxygen, through a thickening corrosion product film. Finally, the kinetic and chemical rate orders for corrosion of chloride-contaminated iron precluded a diffusion-controlled mechanism, but were consistent with a rate-controlling process involving some regeneration of chloride: e.g. as in metal-ion hydrolysis in a pit or similar localised corrosion events
从"电磁学"到"电路分析基础"——对电路问题的几点思考%From"Electromagnetism"to"Circuit Analysis"——Some Reflects on Problems of Electric Circuits
Institute of Scientific and Technical Information of China (English)
From electromagnetism to fundamentals of electric circuit analysis, some reflects are given out, and it has some reference value for students to comprehend knowledge of electric circuits.% 分析了"电路分析基础"课程的"电磁学"理论基础,以帮助学生理解电路知识。
Application of Fast Vacuum Circuit Breaker in Electric System%快速真空断路器在电力系统中的应用
Institute of Scientific and Technical Information of China (English)
艾绍贵; 马奎; 吴旭涛; 孙丽琼
介绍了涡流驱动型快速真空断路器的原理,分析了目前配网消弧消谐、故障选线及触电防护、电网短路电流限制、串联补偿及变压器直流偏磁抑制等技术的现状和存在的问题。根据快速真空断路器特点,提出了解决相关技术问题的方法,阐述了相关装置的结构、试验及应用情况,并对快速真空断路器在电力系统中的应用进行了展望。%Introduction was made to the principle of eddy current forced fast vacuum circuit breaker. Analysis was made to the technolo-gies used and problems existing including arc and resonance elimination, fault line selection and electric shock protection, grid short-circuit current limitation, series compensation and transformer direct current magnetic bias suppression etc technologies in distribution network at present. According to the characteristic of fast vacuum circuit breaker, the solution method of those problems was proposed. This paper ex-pounded the structure, experiment and application of the relevant device. The further application of the circuit breaker is prospected.
Institute of Scientific and Technical Information of China (English)
The paper introduces the magnetic circuits and their relatives inelectric Machinery Course, including the ferromagnetics, law of magnetic circuit, law of electromagnetic induction and the inductance reactance, from the need for the course teaching. The topics which have seldom or not been presented in or textbooks, and are necessary for the Electric Machinery teaching, and are closely in tegrated with the properties of electric machines and transformers are stressed. And, some strict definitions of explanations for the analyses of magnetic circuits are give.%本文从电机学要求出发,介绍磁路及相关内容,它主要包括铁磁物质、磁路定律、电磁感应定律和电感的电抗等问题。本文着重介绍在电路与电机学教科书中介绍甚少或没有提及而又是电机学十分需要的、以及结合电机与变压器特点的这方面的内容。此外,本文还对磁路及相关内容中的一些问题给予严格的定义或说明。
Design of protection circuit for lithium battery used in electric bicycle%电动自行车锂电池组保护电路设计
Institute of Scientific and Technical Information of China (English)
许英杰; 孙郅佶; 李帆; 范贤光
The lithium battery with superior performance is the development trend of the electric bicycle power, but needs a dedicated protection circuit to work with so as to ensure the safety and long-period operation. In this paper, a protection circuit board including S-8209A was designed for the lithium battery set with 4-parallel and 10-serial connection mode. It achieved the functions of overcharge protection, overdischarge protection, overcharge-overdischarge balance and overcurrent protection. The circuit has been already applied to the electric bikes with the lithium batteries.%为保证电动自行车锂电池组安全、长寿命的运行,需为其配备专用管理保护电路.为此,针对一款4并10串规格的锂电池组设计了一套保护电路板,采用S-8209A保护芯片,实现了过充电保护、过放电保护、电池充放电平衡、过电流保护、正常带载等功能,已被可靠应用于某款电动自行车的锂电池组中.
Lightning risk warnings based on atmospheric electric field measurements in Brazil
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Marco Antonio da Silva Ferro*
Full Text Available This paper presents a methodology that employs the electrostatic field variations caused by thundercloud formation or displacement to generate lightning warnings over a region of interest in Southeastern Brazil. These warnings can be used to prevent accidents during hazardous operations, such as the manufacturing, loading, and test of motor-rockets. In these cases, certain equipment may be moved into covered facilities and personnel are required to take shelter. It is also possible to avoid the threat of natural and triggered lightning to launches. The atmospheric electric field database, including the summer seasons of 2007/2008 and 2008/2009 (from November to February, and, for the same period and region, the cloud-to-ground lightning data provided by the Brazilian lightning detection network – BrasilDAT – were used in order to perform a comparative analysis between the lightning warnings and the cloud-to- ground lightning strikes that effectively occurred inside the area of concern. The analysis was done for three areas surrounding the sensor installation defined as circles with 5, 10 and 15 km of radius to determine the most effective detection range. For each area it was done using several critical electric field thresholds: +/- 0.5; +/- 0.8; +/- 0.9; +/- 1.0; +/- 1.2; and +/- 1.5 kV/m. As a result of the reduction of atmospheric electric field data provided by the sensor installed in area of concern and lightning provided by BrasilDAT, it was possible, for each of the areas of alert proposals, to obtain the following parameters: the number of effective alarms; the number of false alarms; and the number of failure to warning. From the analysis of these parameters, it was possible to conclude that, apparently, the most interesting critical electric field threshold to be used is the level of 0.9 kV/m in association with a distance range of 10 km around the point where the sensor is installed.
Hickman, Ian
Analog Circuits Cookbook presents articles about advanced circuit techniques, components and concepts, useful IC for analog signal processing in the audio range, direct digital synthesis, and ingenious video op-amp. The book also includes articles about amplitude measurements on RF signals, linear optical imager, power supplies and devices, and RF circuits and techniques. Professionals and students of electrical engineering will find the book informative and useful.
Process and circuit for operating an electric locomotive with several drive motors working in parallel from one inverter. Verfahren und Schaltungsanordnung zum Betrieb eines elektrischen Triebfahrzeugs mit mehreren an einem Umrichter parallel arbeitenden Antriebsmotoren
Energy Technology Data Exchange (ETDEWEB)
Niehage, H.
With several asynchronous motors fed in parallel via one inverter from an intermediate DC circuit, which drive the various sets of wheels of an electric locomotive, one should prevent that if the slip between the wheel and the rail increases on one set of wheels, the torque of the synchronous motor driving the slipping set of wheels from being transferred to the other parallel asynchronous motors. For this reason each asynchronous motor has a current transformer, which detects the phase currents and takes them to a measurement circuit forming the sum of the phase currents. The sum of the phase currents for each asynchronous motor is compared with the current in the intermediate DC circuit, which is detected via a DC converter and is reduced to a reference level by a quantity forming circuit. The dynamic differences between the motor currents occurring during slipping are detected in difference circuits and are added in a subsequent quantity forming circuit. The signal supplied from this latter circuit is treated by a function forming circuit, which gives a quick reduction of the intermediate circuit power via the control circuit of the intermediate circuit of the inverter.
A New Approach for Modeling Darrieus-Type Vertical Axis Wind Turbine Rotors Using Electrical Equivalent Circuit Analogy: Basis of Theoretical Formulations and Model Development
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Pierre Tchakoua
Full Text Available Models are crucial in the engineering design process because they can be used for both the optimization of design parameters and the prediction of performance. Thus, models can significantly reduce design, development and optimization costs. This paper proposes a novel equivalent electrical model for Darrieus-type vertical axis wind turbines (DTVAWTs. The proposed model was built from the mechanical description given by the Paraschivoiu double-multiple streamtube model and is based on the analogy between mechanical and electrical circuits. This work addresses the physical concepts and theoretical formulations underpinning the development of the model. After highlighting the working principle of the DTVAWT, the step-by-step development of the model is presented. For assessment purposes, simulations of aerodynamic characteristics and those of corresponding electrical components are performed and compared.
Atmospheric electric discharges and grounding systems; Descargas atmosfericas y sistemas de conexion a tierra
Energy Technology Data Exchange (ETDEWEB)
Rivas, Elena [ed.] [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)
In this article the work made by the Institute of Investigaciones Electricas (IIE), in the area of atmospheric electric discharges and grounding connections at Comision Federal de Electricidad (CFE) is presented. The work consisted of the revision of the procedures for the design of transmission lines and substations of CFE from which high indexes of interruptions are reported, from this, a program was defined that allowed to improve the existing designs in CFE. [Spanish] En este articulo se presenta el trabajo realizado por el Instituto de Investigaciones Electricas (IIE), en el area de descargas atmosfericas y conexiones a tierra en Comision Federal de Electricidad (CFE). El trabajo consistio en la revision de los procedimientos de diseno de las areas de transmision y subestaciones de la CFE para los que se reportan altos indices de salidas, a partir de esto se definio un programa que permitio mejorar los disenos existentes en la CFE.
一类自突触作用下神经元电路的设计和模拟∗%Simulation of electric activity of neuron by setting up a reliable neuronal circuit driven by electric autapse
Institute of Scientific and Technical Information of China (English)
任国栋; 武刚; 马军; 陈旸
Transition of electric activity of neuron can be induced by electric autapse, and its action potential is much sensitive to the stimuli from the electric autapse. Generally, the effect of electric autapse on membrane potential of neuron is often described by using time-delayed feedback in closed loop. Based on Pspice software, a class of electric circuit is designed with the electric autapse being taken into consideration, and a time-delayed circuit is used to detect the adjusting action of electric autapse on the action potential. Results are found as follows: (1) The neuronal electric circuit can produce quiescent state, spiking, bursting state under an external force besides the electric autapse circuit. (2) The transition of electric activity occurs between four different atates (quiescent, spiking, bursting state) by imposing a time-varying forcing current; its potential mechanism is that the electric circuit is associated with the memory, and the neuron can give different types of response to the same external forcing current. (3)When a strong external force is imposed, the outputs can show different type of electric activities due to an electric autapse, that is to say, self-adaption of gain in the autapse is useful for the neuron and thus different type of electric activities occurs, whose potential mechanism may be due to the effective feedback in the loop;so it is helpful to understand the synaptic plasticity.%神经元在自突触作用下可以诱发各类放电活动的迁移,神经元动作电位对电自突触的响应比较敏感.通常用包含延迟因子和增益的反馈回路电流来刻画自突触对神经元动作电位的影响.基于Pspice软件,设计了包含自突触效应的神经元电路,用以延迟反馈电路来模拟电自突触对电位的调制作用.研究结果发现:1)在外界刺激和电自突触回路协同作用下,神经元电路输出信号可以呈现静息态,尖峰放电,簇放电状态.2)在时变增�
Diurnal variations of 218Po, 214Pb, and 214Po and their effect on atmospheric electrical conductivity in the lower atmosphere at Mysore city, Karnataka State, India
International Nuclear Information System (INIS)
The short-lived radon daughters (218Po, 214Pb, 214Bi and 214Po) are natural tracers in the troposphere, in particular near the ground surface. They are electrically charged particles and are chemically reactive. As soon as they are formed they get attached to the aerosol particles of the atmosphere. The behavior of radon daughters is similar to that of aerosols with respect to their growth, transport and removal processes in the atmosphere. The electrical conductivity of the atmosphere is mainly due to the presence of highly mobile ions. Galactic cosmic rays are the main source of ionization in the planetary boundary layer; however, near the surface of the earth, ions are produced mainly by decays of natural radioactive gases emanating from the soil surface and by radiations emitted directly from the surface. Hence the electrical conductivity of air near the surface of the earth is mainly due to radiations emitted by 222Rn, 218Po, 214Pb, 214Bi and 214Po, and depends on aerosol concentrations and meteorological parameters. In the present work the diurnal and seasonal variations of radon and its progeny concentrations are studied using Low Level Radon Detection System and Airflow Meter respectively. Atmospheric electrical conductivity of both positive and negative polarities is measured using a Gerdien Condenser. All the measurements were carried out simultaneously at one location in Mysore city (12°N, 76°E), India. The diurnal variation of atmospheric electrical conductivity was found to be similar to that of ion pair production rate estimated from radon and its progeny concentrations with a maximum in the early morning hours and minimum during day time. The annual average concentrations of 222Rn, 218Po, 214Pb, and 214Po at the study location were found to be 21.46, 10.88, 1.78 and 1.80 Bq m−3 respectively. The annual average values of positive and negative atmospheric electrical conductivity were found to be 18.1 and 16.6 f S m−1 respectively. The radon and
Diurnal variations of (218)Po, (214)Pb, and (214)Po and their effect on atmospheric electrical conductivity in the lower atmosphere at Mysore city, Karnataka State, India.
Pruthvi Rani, K S; Paramesh, L; Chandrashekara, M S
The short-lived radon daughters ((218)Po, (214)Pb, (214)Bi and (214)Po) are natural tracers in the troposphere, in particular near the ground surface. They are electrically charged particles and are chemically reactive. As soon as they are formed they get attached to the aerosol particles of the atmosphere. The behavior of radon daughters is similar to that of aerosols with respect to their growth, transport and removal processes in the atmosphere. The electrical conductivity of the atmosphere is mainly due to the presence of highly mobile ions. Galactic cosmic rays are the main source of ionization in the planetary boundary layer; however, near the surface of the earth, ions are produced mainly by decays of natural radioactive gases emanating from the soil surface and by radiations emitted directly from the surface. Hence the electrical conductivity of air near the surface of the earth is mainly due to radiations emitted by (222)Rn, (218)Po, (214)Pb, (214)Bi and (214)Po, and depends on aerosol concentrations and meteorological parameters. In the present work the diurnal and seasonal variations of radon and its progeny concentrations are studied using Low Level Radon Detection System and Airflow Meter respectively. Atmospheric electrical conductivity of both positive and negative polarities is measured using a Gerdien Condenser. All the measurements were carried out simultaneously at one location in Mysore city (12°N, 76°E), India. The diurnal variation of atmospheric electrical conductivity was found to be similar to that of ion pair production rate estimated from radon and its progeny concentrations with a maximum in the early morning hours and minimum during day time. The annual average concentrations of (222)Rn, (218)Po, (214)Pb, and (214)Po at the study location were found to be 21.46, 10.88, 1.78 and 1.80 Bq m(-3) respectively. The annual average values of positive and negative atmospheric electrical conductivity were found to be 18.1 and 16.6 f S m(-1
Processamento de placas de circuito impresso de equipamentos eletroeletrônicos de pequeno porte Processing of printed circuit boards of small electrical and electronic devices
Directory of Open Access Journals (Sweden)
Sérgio de Souza Henrique Júnior
Full Text Available A hydrometallurgical process applicable to printed circuit boards of small electrical and electronic devices was developed. This involved three leaching steps (60 ºC, 2 h: 6 mol L-1 NaOH, 6 mol L-1 HCl and aqua regia. NaOH removed the resin and flame retardant that covered the circuit boards. HCl dissolved the most electropositive metals and a small amount of copper (~0.3 wt%. Aqua regia dissolved the noble metals. Silver precipitated as AgCl. Gold and platinum were quantitatively extracted with pure methyl-isobutylketone and Alamine 336 (10 % vol. in kerosene, respectively. Slow evaporation of the raffinate crystallized CuCl2.4H2O (89% yield.
Long-term changes in atmospheric electrical parameters observed at Nagycenk (Hungary and the UK observatories at Eskdalemuir and Kew
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F. Märcz
Full Text Available The Nagycenk Geophysical Observatory in Hungary (47° 38 ' N, 16° 43 ' E has made continuous measurements of the vertical atmospheric electric Potential Gradient (PG since 1962. Global signals have previously been identified in the Nagycenk PG data. A long-term (1920–1981 decrease has been discovered in the PG measured at the Eskdalemuir Observatory, Scotland (55° 19 ' N, 3° 12 ' W, suggesting that this represents a global change in the atmospheric electricity related to a decline in cosmic rays. A 40% decline in PG is shown here to have occurred at Nagycenk between 1962 and 2001, also consistent with changes in the air-Earth current measured at Kew (51° 28 ' N, 0° 19 ' W, London, 1966–1978. Comparison of the long-term PG measurements at both Eskdalemuir and Nagycenk gives further evidence to support the hypothesis of a global atmospheric electrical decline from the early twentieth century to the present time, as it is shown that local effects at Nagycenk are unlikely to have dominated the changes there.
Key words. Meteorology and atmospheric dynamics (atmospheric electricity
Laurent Guiraud
A printed circuit board made by scientists in the ATLAS collaboration for the transition radiaton tracker (TRT). This will read data produced when a high energy particle crosses the boundary between two materials with different electrical properties.
Electrical and spectral characteristics of an atmospheric pressure argon plasma jet generated with tube-ring electrodes in surface dielectric barrier discharge
International Nuclear Information System (INIS)
An atmospheric-pressure argon plasma jet is generated with tube-ring electrodes in surface dielectric barrier discharge by a sinusoidal excitation voltage at 8 kHz. The electrical and spectral characteristics are estimated such as conduction and displacement current, electric-field, electron temperature, rotational temperature of N2 and OH, electronic excitation temperature, and oxygen atomic density. It is found that the electric-field magnitudes in the top area of the ground electrode are higher than that in the bottom area of the power electrode, and the electron temperature along radial direction is in the range of 9.6–10.4 eV and along axial direction in the range of 4.9–10 eV. The rotational temperature of N2 obtained by comparing the simulated spectrum with the measured spectrum at the C3Πu → B3Πg(Δv = − 2) band transition is in the range of 342–387 K, the electronic excitation temperature determined by Boltzmann's plot method is in the range of 3188–3295 K, and the oxygen atomic density estimated by the spectral intensity ratio of atomic oxygen line λ = 844.6 nm to argon line λ = 750.4 nm is in the order of magnitude of 1016 cm−3, respectively. - Highlights: ► The conduction and displacement current are calculated by equivalent circuit diagram. ► The 2D distribution of electric-field magnitude is calculated by ElecNet software. ► The electron temperature along axial direction is in the range of 4.9–10 eV. ► The oxygen atomic density is about a magnitude of 1016 cm−3
Short Circuit Calculation Method for Marine Power Electrical System%舰船电力系统短路计算方法研究
Institute of Scientific and Technical Information of China (English)
随着我国舰船技术的迅猛发展,上世纪80年代出台的短路计算相关标准存在诸多局限性.首先对GJB173-1986进行探讨,分析其在当前舰船电力系统中存在的不足;继而简述叠加原理法在实船环境下的不足之处,分析层等效法在实际船用电力系统中的性能,以及其在实船应用中的各种优势,最后得出层等效法是目前较适用于舰船电力系统短路计算方法的结论.%With the great development of ship technology in China, there are more and more bugs in related criterions for the short circuit calculation of marine electrical power systems. We firstly analyzed and concluded the shorts of GJB173-1986, and summarized the keystone of the short circuit calculation algorithm based on superposition theorem, with the lacks in the marine circumstance application of algorithm. Then we introduced the level-equivalent algorithm advanced in the latest three years, expounded its performance and summed up its advantages in marine electrical power systems. At last, we concluded that the level-equivalent algorithm is an algorithm with the best performance for short circuit calculation in marine electrical power systems.
Wolfendale, E
MOS Integral Circuit Design aims to help in the design of integrated circuits, especially large-scale ones, using MOS Technology through teaching of techniques, practical applications, and examples. The book covers topics such as design equation and process parameters; MOS static and dynamic circuits; logic design techniques, system partitioning, and layout techniques. Also featured are computer aids such as logic simulation and mask layout, as well as examples on simple MOS design. The text is recommended for electrical engineers who would like to know how to use MOS for integral circuit desi
Electrifying atmospheres charging, ionisation and lightning in the solar system and beyond
Aplin, Karen L
Electrical processes take place in all planetary atmospheres. There is evidence for lightning on Venus, Jupiter, Saturn, Uranus and Neptune, it is possible on Mars and Titan, and cosmic rays ionise every atmosphere, leading to charged droplets and particles. Controversy surrounds the role of atmospheric electricity in physical climate processes on Earth; here, a comparative approach is employed to review the role of electrification in the atmospheres of other planets and their moons. This book reviews the theory, and, where available, measurements, of planetary atmospheric electricity, taken to include ion production and ion-aerosol interactions. The conditions necessary for a global atmospheric electric circuit similar to Earth's, and the likelihood of meeting these conditions in other planetary atmospheres, are briefly discussed. Atmospheric electrification is more important at planets receiving little solar radiation, increasing the relative significance of electrical forces. Nucleation onto atmospheric ...
Directory of Open Access Journals (Sweden)
Mihai MAGYARI
Full Text Available The electric power drive systems consisting of three phase induction motor and static frequency converter are designed to enhance the performance on site, by diminishing the energy consumption, optimization of the technological processes and the reduction of costs for the maintenance and repairs of the equipment. The paper presents some important issues concerning the selection of inverter fed flameproof electric drives in the field of potentially explosive atmospheres of gases and vapors by ensuring a correct risk management against the hazard of electric sparks as well as excessive temperatures
An influence of the petrol pump for the atmospheric electric field distribution in the surroundings of the vehicles
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Milovanović Alenka
Full Text Available In this paper the potential and electric field distribution in the surroundings of the cargo vehicles is approximately numerically determined, when they are exposed to the Atmospheric Electric Field (AEF, having uniform intensity and vertical polarization. The cases of the cargo vehicles either isolated or near by petrol pumps are observed. Several results of total induced charge and electrical moment of the vehicle including maps of equipotential and equienergetic curves are presented. The Equivalent Electrode Method (EEM is used to solve this problem.
Electrodynamical Coupling of Earth's Atmosphere and Ionosphere: An Overview
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A. K. Singh
Full Text Available Electrical processes occurring in the atmosphere couple the atmosphere and ionosphere, because both DC and AC effects operate at the speed of light. The electrostatic and electromagnetic field changes in global electric circuit arise from thunderstorm, lightning discharges, and optical emissions in the mesosphere. The precipitation of magnetospheric electrons affects higher latitudes. The radioactive elements emitted during the earthquakes affect electron density and conductivity in the lower atmosphere. In the present paper, we have briefly reviewed our present understanding of how these events play a key role in energy transfer from the lower atmosphere to the ionosphere, which ultimately results in the Earth's atmosphere-ionosphere coupling.
A Study of University Students' Understanding of Simple Electric Circuits. Part 2: Batteries, Ohm's Law, Power Dissipated, Resistors in Parallel.
Picciarelli, V.; And Others
Results of a systematic investigation into university students' (n=236) misunderstandings of d.c. simple circuit operations are reported. These results provide evidence of various misconceptions present before and after teaching the following topics: a battery as a source of constant current; the functional relation expressed by Ohm's law; power…
Module Nine: Relationships of Current, Counter EMF, and Voltage in LR Circuits; Basic Electricity and Electronics Individualized Learning System.
Bureau of Naval Personnel, Washington, DC.
The student will study the ways that inductance affects voltage and current in Direct Current (DC) and Alternating Current (AC) circuits and why and how inductors cause these actions. The module is divided into six lessons: rise and decay of current and voltage, LR (inductive-resistive) time constant, using the universal TC (time constant) chart,…
Determining atmospheric electric fields from the radio footprint of cosmic-ray induced extensive air showers as measured with LOFAR
Ebert, U.; Trinh, G. T. N.; Buitink, S.; Corstanje, A.; Enriquez, J. E.; Falcke, H.; Horandel, J.; Koehn, C.; Nelles, A.; Rachen, J. P.; Rutjes, C.; Schellart, P.; Scholten, O.; ter Veen, S.; Thoudam, S.
Energetic cosmic rays impinging on the atmosphere create a particle avalanche called extensive air shower. In the leading plasma of this shower, electric currents are induced that generate the emission of radio waves which have been detected with LOFAR (www.lofar.org), an array of a large number of
Flip-flop logic circuit based on fully solution-processed organic thin film transistor devices with reduced variations in electrical performance
Takeda, Yasunori; Yoshimura, Yudai; Adib, Faiz Adi Ezarudin Bin; Kumaki, Daisuke; Fukuda, Kenjiro; Tokito, Shizuo
Organic reset-set (RS) flip-flop logic circuits based on pseudo-CMOS inverters have been fabricated using full solution processing at a relatively low process temperatures of 150 °C or less. The work function for printed silver electrodes was increased from 4.7 to 5.4 eV through surface modification with a self-assembled monolayer (SAM) material. A bottom-gate, bottom-contact organic thin-film transistor (OTFT) device using a solution-processable small-molecular semiconductor material exhibited field-effect mobility of 0.40 cm2 V-1 s-1 in the saturation region and a threshold voltage (VTH) of -2.4 V in ambient air operation conditions. In order to reduce the variations in mobility and VTH, we designed a circuit with six transistors arranged in parallel, in order to average out their electrical characteristics. As a result, we have succeeded in reducing these variations without changing the absolute values of the mobility and VTH. The fabricated RS flip-flop circuits were functioned well and exhibited short delay times of 3.5 ms at a supply voltage of 20 V.
Data transfer of long distance based on electric current loop circuit%基于电流环电路的远距离数据传输
Institute of Scientific and Technical Information of China (English)
李绍卓; 王薇
Level switch is widely used in the process of data transfer of long distance in the area of the industrial control. This paper mainly discusses the electric current loop, which is another data transfer circuit. This circuit switches level singal to current singal, taking current as the carrier of data transfer. This circuit has the excellent performance of anti-noise in the vile industrial environment.%电平转换在工业控制远距离数据传输过程中被广泛采用,取得了良好的效果。阐述了另一种数据传输的电路——电流环,该电路将电平信号转换为电流信号,以电流作为数据传输的载体,在恶劣工业环境下具有较强的抗噪、抗干扰的能力。
Design and construction of prototype transversely excited atmospheric (TEA) nitrogen laser energized by a high voltage electrical discharge
Mukhtar Hussain; Tayyab Imran
The present study reports design and construction, of a prototype of Transversely Excited Atmospheric (TEA) nitrogen laser, and a high voltage power supply to excite N2 gas in air, while air is used as an active lasing medium. A Blumlein line discharge circuit is used for operation of this laser. The high voltage is generated by a fly back transformer based power supply varying from 10 kV to 20 kV. The wavelength (337.1 nm) of TEA nitrogen laser is measured employing a standard commercial spe...
Electric Circuit Model for the Aerodynamic Performance Analysis of a Three-Blade Darrieus-Type Vertical Axis Wind Turbine: The Tchakoua Model
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Pierre Tchakoua
Full Text Available The complex and unsteady aerodynamics of vertical axis wind turbines (VAWTs pose significant challenges for simulation tools. Recently, significant research efforts have focused on the development of new methods for analysing and optimising the aerodynamic performance of VAWTs. This paper presents an electric circuit model for Darrieus-type vertical axis wind turbine (DT-VAWT rotors. The novel Tchakoua model is based on the mechanical description given by the Paraschivoiu double-multiple streamtube model using a mechanical‑electrical analogy. Model simulations were conducted using MATLAB for a three-bladed rotor architecture, characterized by a NACA0012 profile, an average Reynolds number of 40,000 for the blade and a tip speed ratio of 5. The results obtained show strong agreement with findings from both aerodynamic and computational fluid dynamics (CFD models in the literature.
Dynamic electric behavior and open-circuit-voltage modeling of LiFePO{sub 4}-based lithium ion secondary batteries
Energy Technology Data Exchange (ETDEWEB)
Roscher, Michael A.; Sauer, Dirk Uwe [RWTH Aachen University, Electrochemical Energy Conversion and Storage Systems Group, Institute for Power, Electronics and Electrical Drives (ISEA), Jaegerstrasse 17-19, 52066 Aachen (Germany)
Accurate battery modeling is one of the key factors in battery system design process and operation as well. Therefore, the knowledge of the distinct electric characteristics of the battery cells is mandatory. This work gives insight to the electric characteristics of lithium ion batteries (Li-ion) comprising LiFePO{sub 4}-based cathode active materials with emphasis on their specific open-circuit-voltage (OCV) characteristics including hysteresis and special OCV recovery effects, which last for several minutes or even hours after a current load is interrupted. These effects are elucidated incorporating OCV measurement data of high power cells. Simple empiric models are derived and used in a model-based state estimation algorithm. The complete battery model includes an impedance model, a hysteresis model and an OCV recovery model part. The introduced model enables the assessment of the cells' state-of-charge (SOC) precisely using model-based state estimation approaches. (author)
Cloud conditions for low atmospheric electricity during disturbed period after the Fukushima nuclear accident
Yatagai, Akiyo; Yamauchi, Masatoshi; Ishihara, Masahito; Watanabe, Akira; Murata, Ken T.
The vertical (downward) component of the atmospheric electric field, or potential gradient (PG) under cloud generally reflects the electric charge distribution in the cloud. The PG data at Kakioka, 150 km southwest of the Fukushima Dai-ichi Nuclear Power Plant (FNPP1) suggested that this relation can be modified when the radioactive dust was floating in the air, and the exact relation between the weather and this modification could lead to new insight in plasma physics in the wet atmosphere. Unfortunately the detailed weather data was not available above Kakioka (only the precipitation data was available). Therefore, estimation of the cloud condition during March 2011 was strongly needed. We have developed various meteorological information links (http://www.chikyu.ac.jp/akiyo/firis/) and original radar and precipitation data will be released from the page. Here we present various radar images that we have prepared for March 2011. We prepared three-dimensional radar reflectivity of the C-band radar of JMA in every 10 minutes over all Kanto Plain centered at Tokyo and Fukushima prefecture centered at Sendai. We have released images of each altitude (1km interval) for 15th - 16thand 21th March (http://sc-web.nict.go.jp/fukushima/). The vertical structure of the rainfall is almost the same at 4km with the surface and sporadic high precipitation is observed at 6 km height for 15-16th. While, generally precipitation pattern that is similar to the surface is observed at 5km height on 21th. On the other hand, an X-band radar centered at Fukushima university is also used to know more localized raindrop patterns at zenith angle of 4 degree. We prepared 10-minutes/120m mesh precipitation patterns for March 15th, 16th, 17th, 18th, 20th, 21th, 22th and 23th. Quantitative estimate is difficult from this X-band radar, but localized structure, especially for the rain-band along Nakadori (middle valley in Fukushima prefecture), that is considered to determine the highly
Ice shedding from overhead electrical lines by mechanical breaking : a ductile model for viscoplastic behaviour of atmospheric ice
Energy Technology Data Exchange (ETDEWEB)
Eskandarian, M.
The mechanical characteristics of power line components need improvement in order to avoid power failures during severe ice storms. Atmospheric icing of overhead power lines creates electrical and mechanical problems in the transmission network. The successful development of anti-icing and de-icing techniques requires good knowledge of the adherence and bulk strength characteristics of atmospheric ice. This study presented a model for viscoplastic behaviour of porous atmospheric ice in the ductile region. The model was then modified to consider the effects of cracking activities to predict the material behaviour in transition and brittle regions. The following general methodologies were followed in this research for describing the ductile behaviour of porous atmospheric ice: instantaneous elastic strain; delayed viscoelastic strain; and, permanent plastic strain. The scientific contributions of this study include a classification of atmospheric ice structure on power lines on the basis of its grain shape and c-axis orientation. This thesis also presented 3 computer codes in Maple Mathematical Program for determining the elastic moduli of various types of freshwater ice; a poroelastic model for modifying the elastic moduli of porous atmospheric ice; a cap-model plasticity for various types of porous atmospheric ice; new freshwater ice yield envelopes in ductile regions that take porosity into account by means of an elliptical moving cap; and a newly developed user-defined material subroutine for viscoplastic behaviour of atmospheric ice in ductile region including the poroelastic, viscoelastic, and cap-model plasticity.
Settlement process of radioactive dust to the ground inferred from the atmospheric electric field measurement
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M. Yamauchi
Full Text Available Radioactive materials from the accident at Fukushima Dai-ichi nuclear power plant (FNPP in March 2011 spread over a large area, increasing the atmospheric electric conductivity by their ionizing effect, and reducing the vertical (downward component of the DC electric field near the ground, or potential gradient (PG. PG data at Kakioka, 150 km away from the FNPP, showed independent changes compared to the radiation dose rate, and a comparison of these data revealed the local dynamics of the radioactive dust.
(1 The initial drop of the PG to almost zero during 14–15 March is most likely due to radioactive dust suspended in the air near the ground during cloudy weather. (2 An episode of PG increase to more than 50 V m−1 on 16 March is most likely due to the re-suspension of the radioactive dust from the surface and subsequent removal from Kakioka by the strong wind from the non-contaminated area. (3 Low but finite values of the PG during 16–20 March most likely reflect a reduced amount of radioactive material near the ground after the above wind transported away the majority of the suspended radioactive dust. (4 Very low values of the PG after substantial rain on 20–22 March most likely reflect settlement of the radioactive material by rain-induced fallout. (5 Temporal recovery of daily variations from the end of March to the middle of April with low nighttime fair-weather baseline PG most likely reflects re-suspension of the radioactive dust into the air from the ground and trees, and subsequent transport to the other region or fallout to the ground until late April. (6 Weakening of the daily variation and gradual recovery of the nighttime fair-weather baseline after mid-April suggests a complete settlement of the radioactive material to the ground with partial migration to the subsurface.
Settlement process of radioactive dust to the ground inferred from the atmospheric electric field measurement
Yamauchi, M.; Takeda, M.; Makino, M.; Owada, T.; Miyagi, I.
Radioactive materials from the accident at Fukushima Dai-ichi nuclear power plant (FNPP) in March 2011 spread over a large area, increasing the atmospheric electric conductivity by their ionizing effect, and reducing the vertical (downward) component of the DC electric field near the ground, or potential gradient (PG). PG data at Kakioka, 150 km away from the FNPP, showed independent changes compared to the radiation dose rate, and a comparison of these data revealed the local dynamics of the radioactive dust. (1) The initial drop of the PG to almost zero during 14-15 March is most likely due to radioactive dust suspended in the air near the ground during cloudy weather. (2) An episode of PG increase to more than 50 V m-1 on 16 March is most likely due to the re-suspension of the radioactive dust from the surface and subsequent removal from Kakioka by the strong wind from the non-contaminated area. (3) Low but finite values of the PG during 16-20 March most likely reflect a reduced amount of radioactive material near the ground after the above wind transported away the majority of the suspended radioactive dust. (4) Very low values of the PG after substantial rain on 20-22 March most likely reflect settlement of the radioactive material by rain-induced fallout. (5) Temporal recovery of daily variations from the end of March to the middle of April with low nighttime fair-weather baseline PG most likely reflects re-suspension of the radioactive dust into the air from the ground and trees, and subsequent transport to the other region or fallout to the ground until late April. (6) Weakening of the daily variation and gradual recovery of the nighttime fair-weather baseline after mid-April suggests a complete settlement of the radioactive material to the ground with partial migration to the subsurface.
Settlement process of radioactive dust to the ground inferred from the atmospheric electric field measurement
Energy Technology Data Exchange (ETDEWEB)
Yamauchi, M. [Swedish Institute of Space Physics, Kiruna (Sweden); Takeda, M. [Kyoto Univ. (Japan). Data Analysis Center for Geomagnetism and Space Magnetism; Makino, M.; Miyagi, I. [National Institute of Advanced Industrial Science and Technology, Tsukuba (Japan); Owada, T. [Japan Meteorological Agency, Ishioka (Japan). Kakioka Magnetic Observatory
Radioactive materials from the accident at Fukushima Dai-ichi nuclear power plant (FNPP) in March 2011 spread over a large area, increasing the atmospheric electric conductivity by their ionizing effect, and reducing the vertical (downward) component of the DC electric field near the ground, or potential gradient (PG). PG data at Kakioka, 150 km away from the FNPP, showed independent changes compared to the radiation dose rate, and a comparison of these data revealed the local dynamics of the radioactive dust. (1) The initial drop of the PG to almost zero during 14-15 March is most likely due to radioactive dust suspended in the air near the ground during cloudy weather. (2) An episode of PG increase to more than 50Vm{sup -1} on 16 March is most likely due to the re-suspension of the radioactive dust from the surface and subsequent removal from Kakioka by the strong wind from the non-contaminated area. (3) Low but finite values of the PG during 16-20 March most likely reflect a reduced amount of radioactive material near the ground after the above wind transported away the majority of the suspended radioactive dust. (4) Very low values of the PG after substantial rain on 20-22 March most likely reflect settlement of the radioactive material by rain-induced fallout. (5) Temporal recovery of daily variations from the end of March to the middle of April with low nighttime fair-weather baseline PG most likely reflects re-suspension of the radioactive dust into the air from the ground and trees, and subsequent transport to the other region or fallout to the ground until late April. (6) Weakening of the daily variation and gradual recovery of the nighttime fair-weather baseline after mid-April suggests a complete settlement of the radioactive material to the ground with partial migration to the subsurface. (orig.)
Microstructural evolution of Cu-1at% Ti alloy aged in a hydrogen atmosphere and its relation with the electrical conductivity
Semboshi, Satoshi
Copper alloys with titanium additions between 1 and 6 at% Ti emerge currently as attractive conductive materials for electrical and electronic commercial products, since they exhibit superior mechanical and electrical properties. However, their electrical conductivity is reduced owing to the residual amount of Ti solutes in the Cu solid solution (Cu(ss)) phase. Since Cu shows only poor reactivity with hydrogen (H), while Ti exhibits high affinity to it, we were inspired by the idea that hydrogenation of Cu-Ti alloys would influence their microstructure, resulting in a significant change of their properties. In this contribution, the influence of aging under a deuterium (D(2)) atmosphere of Cu-1 at% Ti alloys on their microstructure is investigated to explore the effects on the electrical conductivity. The specimens were investigated by means of transmission electron microscopy (TEM), field ion microscopy (FIM), computer-aided field ion image tomography (cFIIT), and atom probe tomography (APT). At an early aging stage at 623 K in a D(2) atmosphere of 0.08 Wit, ellipsoidal alpha-Cu(4)Ti precipitates are formed in the alloy, and during subsequent aging, delta-TiD(2) is competitively nucleated instead of growth of alpha-Cu(4)Ti particles. The co-precipitation of alpha-Cu(4)Ti and delta-TiD(2) efficiently reduces the Ti concentration of Cuss matrix, particularly in the later aging stages in comparison to the aging in vacuum conditions. The electrical conductivity of the alloy aged in the D(2) atmosphere increases steeply up to 48% International Annealed Copper Standard (IACS) after 1030 It, while it saturates to approximately 20% IACS in the alloy aged in vacuum. The outstanding increase of electrical conductivity during aging in D2 atmosphere can be basically explained by the reduction of Ti solute concentration in Cuss matrix. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.
Linking neuroscientific research on decision making to the educational context of novice students assigned to a multiple-choice scientific task involving common misconceptions about electrical circuits
Directory of Open Access Journals (Sweden)
Patrice ePotvin
Full Text Available Functional magnetic resonance imaging was used to identify the brain-based mechanisms of uncertainty and certainty associated with answers to multiple-choice questions involving common misconceptions about electric circuits. Twenty-two (22 scientifically novice participants (humanities and arts college students were asked, in an fMRI study, whether or not they thought the light bulbs in images presenting electric circuits were lighted up correctly, and if they were certain or uncertain of their answers. When participants reported that they were unsure of their responses, analyses revealed significant activations in brain areas typically involved in uncertainty (anterior cingulate cortex, anterior insula cortex, and superior/dorsomedial frontal cortex and in the left middle/superior temporal lobe. Certainty was associated with large bilateral activations in the occipital and parietal regions usually involved in visuospatial processing. Correct-and-certain answers were associated with activations that suggest a stronger mobilization of visual attention resources when compared to incorrect-and-certain answers. These findings provide insights into brain-based mechanisms of uncertainty that are activated when common misconceptions, identified as such by science education research literature, interfere in decision making in a school-like task. We also discuss the implications of these results from an educational perspective.
Online model-based estimation of state-of-charge and open-circuit voltage of lithium-ion batteries in electric vehicles
International Nuclear Information System (INIS)
This paper presents a method to estimate the state-of-charge (SOC) of a lithium-ion battery, based on an online identification of its open-circuit voltage (OCV), according to the battery's intrinsic relationship between the SOC and the OCV for application in electric vehicles. Firstly an equivalent circuit model with n RC networks is employed modeling the polarization characteristic and the dynamic behavior of the lithium-ion battery, the corresponding equations are built to describe its electric behavior and a recursive function is deduced for the online identification of the OCV, which is implemented by a recursive least squares (RLS) algorithm with an optimal forgetting factor. The models with different RC networks are evaluated based on the terminal voltage comparisons between the model-based simulation and the experiment. Then the OCV-SOC lookup table is built based on the experimental data performed by a linear interpolation of the battery voltages at the same SOC during two consecutive discharge and charge cycles. Finally a verifying experiment is carried out based on nine Urban Dynamometer Driving Schedules. It indicates that the proposed method can ensure an acceptable accuracy of SOC estimation for online application with a maximum error being less than 5.0%. -- Highlights: ► An equivalent circuit model with n RC networks is built for lithium-ion batteries. ► A recursive function is deduced for the online estimation of the model parameters like OCV and RO. ► The relationship between SOC and OCV is built with a linear interpolation method by experiments. ► The experiments show the online model-based SOC estimation is reasonable with enough accuracy.
Power-factor compensation of electrical circuits. A framework for analysis and design in the nonlinear nonsinusoidal case.
García Canseco, Eloísa; Griñó Cubero, Robert; Ortega, Romeo; Salichs Vivancos, Miguel; Stankovic, Alexander
This article advances an analysis and compensator design framework for power-factor compensation based on cyclodissipativity. Although the framework applies to general polyphase unbalanced circuits, this paper have focused on the problem of power factor compensation with LTI capacitors or inductors of single-phase loads. The full power of the approach are expected to become evident for polyphase unbalanced loads with possibly nonlinear lossless compensators, where the existing solutions are f...
Optimizing the electrical excitation of an atmospheric pressure plasma advanced oxidation process.
Olszewski, P; Li, J F; Liu, D X; Walsh, J L
The impact of pulse-modulated generation of atmospheric pressure plasma on the efficiency of organic dye degradation has been investigated. Aqueous samples of methyl orange were exposed to low temperature air plasma and the degradation efficiency was determined by absorbance spectroscopy. The plasma was driven at a constant frequency of 35kHz with a duty cycle of 25%, 50%, 75% and 100%. Relative concentrations of dissolved nitrogen oxides, pH, conductivity and the time evolution of gas phase ozone were measured to identify key parameters responsible for the changes observed in degradation efficiency. The results indicate that pulse modulation significantly improved dye degradation efficiency, with a plasma pulsed at 25% duty showing a two-fold enhancement. Additionally, pulse modulation led to a reduction in the amount of nitrate contamination added to the solution by the plasma. The results clearly demonstrate that optimization of the electrical excitation of the plasma can enhance both degradation efficiency and the final water quality.
TOPICAL REVIEW: Nucleation and aerosol processing in atmospheric pressure electrical discharges: powders production, coatings and filtration
Borra, Jean-Pascal
This review addresses the production of nano-particles and the processing of particles injected in atmospheric pressure electrical discharges (APED). The mechanisms of formation and the evolution of particles suspended in gases are first presented, with numerical and experimental facilities. Different APED and related properties are then introduced for dc corona, streamer and spark filamentary discharges (FD), as well as for ac filamentary and homogeneous dielectric barrier discharges (DBD). Two mechanisms of particle production are depicted in APED: when FD interact with the surface of electrodes or dielectrics and when filamentary and homogeneous DBD induce reactions with gaseous precursors in volume. In both cases, condensable gaseous species are produced, leading to nano-sized particles by physical and chemical routes of nucleation. The evolution of the so-formed nano-particles, i.e. the growth by coagulation/condensation, the charging and the collection are detailed for each APED, with respect to fine powders production and thin films deposition. Finally, when particles are injected in APED, they undergo interfacial processes. Non-thermal plasmas charge particles for electro-collection and trigger heterogeneous chemical reactions for organic and inorganic films deposition. Heat exchanges in thermal plasmas enable powder purification, shaping, melting for hard coatings and fine powders production by reactive evaporation.
Nucleation and aerosol processing in atmospheric pressure electrical discharges: powders production, coatings and filtration
International Nuclear Information System (INIS)
This review addresses the production of nano-particles and the processing of particles injected in atmospheric pressure electrical discharges (APED). The mechanisms of formation and the evolution of particles suspended in gases are first presented, with numerical and experimental facilities. Different APED and related properties are then introduced for dc corona, streamer and spark filamentary discharges (FD), as well as for ac filamentary and homogeneous dielectric barrier discharges (DBD). Two mechanisms of particle production are depicted in APED: when FD interact with the surface of electrodes or dielectrics and when filamentary and homogeneous DBD induce reactions with gaseous precursors in volume. In both cases, condensable gaseous species are produced, leading to nano-sized particles by physical and chemical routes of nucleation. The evolution of the so-formed nano-particles, i.e. the growth by coagulation/condensation, the charging and the collection are detailed for each APED, with respect to fine powders production and thin films deposition. Finally, when particles are injected in APED, they undergo interfacial processes. Non-thermal plasmas charge particles for electro-collection and trigger heterogeneous chemical reactions for organic and inorganic films deposition. Heat exchanges in thermal plasmas enable powder purification, shaping, melting for hard coatings and fine powders production by reactive evaporation. (topical review)
Some characteristics of electric field momentum coupling with the neutral atmosphere
Mayr, H. G.; Harris, I.
A three-dimensional model has been developed to describe momentum coupling between high-latitude electric fields, neutral winds, temperature, and composition. The Hall drag is found to be the main source for atmospheric winds and the small divergence component of winds is due to the Pedersen drag and the Hall drag. Adiabatic heat transfer is responsible for the back pressure which damps the divergence field and for the reversal in circulation of the divergence field at higher altitudes. Back pressure causes a decrease in total wind velocity of about 10% at exospheric heights and by a factor of about 2 at 120 km. The wind field with the pressure feedback may be simulated by neglecting pressure variations and the Coriolis force. Density variations of Ar, N2, O, and He, induced by the momentum source, are in phase above 120 km and out of phase with the temperature amplitude above 150 km. The electrostatic field momentum source is ineffective for directly inducing density and temperature variations in the upper thermosphere.
Organic synthesis from reducing models of the atmosphere of the primitive earth with UV light and electric discharges.
Bossard, A R; Raulin, F; Mourey, D; Toupance, G
The purpose of this paper is to compare the role of UV light and of electric discharges, the two most important sources of energy on the primitive earth, in the synthesis of organic compounds out of a reducing model of that atmosphere. Since Miller's experiments in 1953, most of the experimental simulations have been performed with electric discharges, and it has been assumed that UV radiations would give similar results. In order to check this assumption we have performed both experimental simulations in our laboratory. Experimental results indicate that this assumption was wrong in a large extent. Our four main conclusions are: 1. Unlike electric discharges, UV light is not an efficient source for producing unsaturated carbon chains. 2. UV light is efficient for producing nitriles in CH4--NH3 mixtures when the mole fraction of NH3 is very low while electric discharges need a higher mole fraction of NH3. 3. UV light is not able to produce nitriles from CH4--N2 mixtures while electric discharges produce important quantities of diversified nitriles from these mixtures. 4. UV light is not very efficient for producing aldehydes from CH4--H2O model atmosphere, electric discharges seem to be able to produce them more efficiently. PMID:7097776
Integrating Solar Power onto the Electric Grid - Bridging the Gap between Atmospheric Science, Engineering and Economics
Ghonima, M. S.; Yang, H.; Zhong, X.; Ozge, B.; Sahu, D. K.; Kim, C. K.; Babacan, O.; Hanna, R.; Kurtz, B.; Mejia, F. A.; Nguyen, A.; Urquhart, B.; Chow, C. W.; Mathiesen, P.; Bosch, J.; Wang, G.
One of the main obstacles to high penetrations of solar power is the variable nature of solar power generation. To mitigate variability, grid operators have to schedule additional reliability resources, at considerable expense, to ensure that load requirements are met by generation. Thus despite the cost of solar PV decreasing, the cost of integrating solar power will increase as penetration of solar resources onto the electric grid increases. There are three principal tools currently available to mitigate variability impacts: (i) flexible generation, (ii) storage, either virtual (demand response) or physical devices and (iii) solar forecasting. Storage devices are a powerful tool capable of ensuring smooth power output from renewable resources. However, the high cost of storage is prohibitive and markets are still being designed to leverage their full potential and mitigate their limitation (e.g. empty storage). Solar forecasting provides valuable information on the daily net load profile and upcoming ramps (increasing or decreasing solar power output) thereby providing the grid advance warning to schedule ancillary generation more accurately, or curtail solar power output. In order to develop solar forecasting as a tool that can be utilized by the grid operators we identified two focus areas: (i) develop solar forecast technology and improve solar forecast accuracy and (ii) develop forecasts that can be incorporated within existing grid planning and operation infrastructure. The first issue required atmospheric science and engineering research, while the second required detailed knowledge of energy markets, and power engineering. Motivated by this background we will emphasize area (i) in this talk and provide an overview of recent advancements in solar forecasting especially in two areas: (a) Numerical modeling tools for coastal stratocumulus to improve scheduling in the day-ahead California energy market. (b) Development of a sky imager to provide short term
Decrease of the electric field penetration into the ionosphere due to low conductivity at the near ground atmospheric layer
Directory of Open Access Journals (Sweden)
M. Ampferer
Full Text Available It is well known that lithospheric electromagnetic emissions are generated before earthquakes occurrence. In our study, we consider the physical penetration mechanism of the electric field from the Earth's surface, through the atmosphere-ionosphere layers, and until its detection in space by satellites. A simplified approach is investigated using the electric conductivity equation, i.e., ∇ˆσ·∇Φ=0 in the case of a vertical inclination of the geomagnetic field lines. Particular interest is given to the conductivity profile near the ground and the electric field distribution at the Earth's surface. Our results are discussed and compared to the models of Pulinets et al. (2003 and Denisenko et al. (2008. It is shown that the near ground atmospheric layer with low conductivity decreases the electric field penetration into the ionosphere. The model calculations have demonstrated that the electric field of lithospheric origin is too weak to be observed at satellite altitudes.
Identification and characterization of the atmospheric emission of polychlorinated naphthalenes from electric arc furnaces.
Liu, Guorui; Zheng, Minghui; Du, Bing; Nie, Zhiqiang; Zhang, Bing; Hu, Jicheng; Xiao, Ke
Electric arc furnaces (EAF) are well recognized as significant sources of dioxins. EAFs have also been speculated to be sources of polychlorinated naphthalenes (PCNs) due to the close correlation between dioxin and PCN formation. However, assessment on PCN emissions from EAFs has not been carried out. The primary aim of this preliminary study is to identify and characterize the atmospheric emission of PCNs from EAFs. In this preliminary study, stack gas samples from two typical EAFs with different scales (EAF-1, 160 t batch(-1); and EAF-2, 60 t batch(-1)) were collected by automatic isokinetic sampling technique, and PCN congeners in samples were analyzed by isotope dilution high-resolution gas chromatography combined with high-resolution mass spectrometry method. Emission concentrations of PCNs were 458 and 1,099 ng m(-3) for EAF-1 and EAF-2, respectively. The emission factors of PCNs to air were 21.6 and 30.1 ng toxic equivalent t(-1) for EAF-1 and EAF-2, respectively, which suggested that EAF is an important source of PCN release. With regard to the characteristics of PCNs from EAFs, lower chlorinated homologues were dominant. The PCN congeners comprised of CN27/30, CN52/60, CN66/67, and CN73 were the most abundant congeners for tetra-, penta-, hexa-, and hepta-chlorinated homologues, respectively. EAFs were identified to be an important PCN source, and the obtained data are useful for developing a PCN inventory. The congener profiles of PCNs presented here might provide helpful information for identifying the specific sources of PCNs emitted from EAFs.
Evaluation and optimization of quartz resonant-frequency retuned fork force sensors with high Q factors, and the associated electric circuits, for non-contact atomic force microscopy.
Ooe, Hiroaki; Fujii, Mikihiro; Tomitori, Masahiko; Arai, Toyoko
High-Q factor retuned fork (RTF) force sensors made from quartz tuning forks, and the electric circuits for the sensors, were evaluated and optimized to improve the performance of non-contact atomic force microscopy (nc-AFM) performed under ultrahigh vacuum (UHV) conditions. To exploit the high Q factor of the RTF sensor, the oscillation of the RTF sensor was excited at its resonant frequency, using a stray capacitance compensation circuit to cancel the excitation signal leaked through the stray capacitor of the sensor. To improve the signal-to-noise (S/N) ratio in the detected signal, a small capacitor was inserted before the input of an operational (OP) amplifier placed in an UHV chamber, which reduced the output noise from the amplifier. A low-noise, wideband OP amplifier produced a superior S/N ratio, compared with a precision OP amplifier. The thermal vibrational density spectra of the RTF sensors were evaluated using the circuit. The RTF sensor with an effective spring constant value as low as 1000 N/m provided a lower minimum detection limit for force differentiation. A nc-AFM image of a Si(111)-7 × 7 surface was produced with atomic resolution using the RTF sensor in a constant frequency shift mode; tunneling current and energy dissipation images with atomic resolution were also simultaneously produced. The high-Q factor RTF sensor showed potential for the high sensitivity of energy dissipation as small as 1 meV/cycle and the high-resolution analysis of non-conservative force interactions. PMID:26931855
Transport of the smoke plume from Chiado's fire in Lisbon (Portugal) sensed by atmospheric electric field measurements
Conceição, Ricardo; Melgão, Marta; Silva, Hugo; Reis, A. Heitor
The Chiado's fire that affected the city centre of Lisbon (Portugal) occurred on 25th August 1988 and had a significant human and environmental impact. This fire was considered the most significant hazard to have occurred in Lisbon city centre after the major earthquake of 1755. A clear signature of this fire is found in the atmospheric electric field data recorded at Portela meteorological station about 8 km NE from the site where the fire started at Chiado. Measurements were mad...
Evolution of short circuit levels in the National Electric System, years 2007 to 2011; Evolucion de los niveles de cortocircuito del Sistema Electrico Nacional, anos 2007 al 2011
Energy Technology Data Exchange (ETDEWEB)
Quintana Castaneda, J; Reyes Escobedo, G [Instituto de Investigaciones Electricas (Mexico)]. E-mails: email@example.com; email@example.com; Ibarra Romo, F.G. [Comision Federal de Electricidad (Mexico)]. E-mail: firstname.lastname@example.com
The present document shows an analysis of 2011 short-circuit levels on the different nodes (substations) that integrate the National Electric System. This analysis presents the figures of short-circuit levels on past years, stating on 2007, with the purpose of detecting the variation on each one of these nodes and identify the cases that because it's high levels are considered as critical nodes of the transmission system. At the end of the analysis some recommendations to minimize the potential risks are given on those substations classified as critical nodes. [Spanish] En este documento se expone un analisis de los niveles de cortocircuito que se presentaron en el 2011 en los distintos nodos (subestaciones) que conforman la red del Sistema Electrico Nacional (SEN). Este analisis muestra las cifras de los niveles de cortocircuito que se han presentado desde el ano 2007, a fin de estudiar el comportamiento y evolucion que han tenido los nodos de la red electrica, identificando aquellos puntos que por sus altos niveles de cortocircuito se consideran como nodos criticos. En la parte final del analisis se dan algunas recomendaciones para disminuir los riesgos que se pudieran presentar en aquellas subestaciones clasificadas como nodos criticos.
光学消像旋的电路控制系统研究%Electric circuit of optical image de-rotation
Institute of Scientific and Technical Information of China (English)
刘飞; 鱼云岐; 郭新胜; 李红光; 韩瑞
针对周视光电观瞄系统中机械传动装置实现光学消像旋的情况,分析了传统光学消像旋的利弊.通过简化机械装置,建立了控制对象的数学模型,根据系统实时控制处理的要求,设计了数字控制和模拟控制的混合电路,提高了系统的稳定性和可靠性.运用MATLAB/SIMU-LINK对控制系统的典型情况进行仿真.仿真结果表明,该电路系统都能满足精度和实时性等指标要求.%Based on the optical image de-rotation implemented by the transmission mechanism of a panoramic observation sight, the advantages and weaknesses of traditional optical de-rotation methods were analyzed. By simplifying the mechanism, the mathematical model of the controlled object was established. According to the system requirements of real-time controlling and processing, the digital-analog control hybrid circuits were designed, which improved the stability and reliability of the system. A typical instance of the control system was simulated with MATLAB/SIMULINK, the results show that the electric circuit can meet the requirements of stability and real-time processing.
Electrical Characterization of Metal-Insulator-Metal Capacitors with Atomic-Layer-Deposited HfO2 Dielectrics for Radio Frequency Integrated Circuit Application
Institute of Scientific and Technical Information of China (English)
HUANG Yu-Jian; HUANG Yue; DING Shi-Jin; ZHANG Wei; LIU Ran
Metal-insulator-metal (MIM) capacitors with atomic-layer-deposited HfO2 dielectric and TaN electrodes are investigated for rf integrated circuit applications. For 12nm HfO2, the fabricated capacitor exhibits a high capacitance density of 15.5fF/μm2 at 100kHz, a small leakage current density of 6.4 × 10-9 A/cm2 at 1.8 V and 125℃, a breakdown electric field of 2.6 MV/cm as well as voltage coefficients of capacitance (VCCs) of 2110ppm/V2 and -824 ppm/V at 100kHz. Further, it is deduced that the conduction mechanism in the high field range is dominated by the Poole-Frenkel emission, and the conduction mechanism in the low field range is possibly related to trap-assisted tunnelling. Finally, comparison of various HfO2 MIM capacitors is present,suggesting that the present MIM capacitor is a promising candidate for future rf integrated circuit application.
The Effect of Air Density on Atmospheric Electric Fields Required for Lightning Initiation from a Long Airborne Object
Bazelyan, E. M.; Aleksandrov, N. L.; Raizer, Yu. Pl.; Konchankov, A. M.
The purpose of the work was to determine minimum atmospheric electric fields required for lightning initiation from an airborne vehicle at various altitudes up to 10 km. The problem was reduced to the determination of a condition for initiation of a viable positive leader from a conductive object in an ambient electric field. It was shown that, depending on air density and shape and dimensions of the object, critical atmospheric fields are governed by the condition for leader viability or that for corona onset. To establish quantitative criteria for reduced air densities, available observations of spark discharges in long laboratory gaps were analyzed, the effect of air density on leader velocity was discussed and evolution in time of the properties of plasma in the leader channel was numerically simulated. The results obtained were used to evaluate the effect of pressure on the quantitative relationships between the potential difference near the leader tip, leader current and its velocity; based on these relationships, criteria for steady development of a leader were determined for various air pressures. Atmospheric electric fields required for lightning initiation from rods and ellipsoidal objects of various dimensions were calculated at different air densities. It was shown that there is no simple way to extend critical ambient fields obtained for some given objects and pressures to other objects and pressures.
Printed transparent electrodes containing carbon nanotubes for elastic circuits applications with enhanced electrical durability under severe conditions
International Nuclear Information System (INIS)
Organic composites filled with nanostructures are new group of materials with unique physical properties. Carbon nanotubes (CNTs) are demonstrating good electrical and mechanical properties. This enables to produce conductive polymer-CNT thick films optically transparent, which are highly useful in production of printed electronic paper. Currently used indium tin oxide (ITO) and antimony tin oxide (ATO) films exhibit high optical transmittance with reasonable electrical conductivity, but very low resilience to mechanical stresses. This is one of the key problems in fabrication of flexible electronic displays. Current authors' achievements include fabrication of transparent electrodes obtained by screen printing technique, used for production of fully functional thick film electroluminescent structures.
Circuit analysis with Multisim
Baez-Lopez, David
This book is concerned with circuit simulation using National Instruments Multisim. It focuses on the use and comprehension of the working techniques for electrical and electronic circuit simulation. The first chapters are devoted to basic circuit analysis.It starts by describing in detail how to perform a DC analysis using only resistors and independent and controlled sources. Then, it introduces capacitors and inductors to make a transient analysis. In the case of transient analysis, it is possible to have an initial condition either in the capacitor voltage or in the inductor current, or bo
Spotting the earth connection and short circuits between the electric conductors, using D.C. bridges for resistance measurements
Popa, I.; Popa, G. N.; Deaconu, S. I.; Iagăr, A.
The paper establishes the necessary connections meant to spot the earth connections and short circuits between the conductors of a power line, using the DC bridges meant for measuring resistances between conductors at the ends of the power line. Since it is a relative method, it imposes an exact knowledge of the faulty power line setting. For values of the resistances measured between the conductors of the power line having over 1Ω at one end, the measurement will be carried out with a Wheatstone bridge, and for values below 1Ω with a Thomson bridge. In order to accurately determine the place of the fault, it measured the distances from the end of the line up to the fault and then we performed a correction calculation for this distance.
49 CFR 236.721 - Circuit, control.
... 49 Transportation 4 2010-10-01 2010-10-01 false Circuit, control. 236.721 Section 236.721..., MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.721 Circuit, control. An electrical circuit between a source of electric energy and a device which it operates....
Nanosecond pulsed electric fields (nsPEFs) low cost generator design using power MOSFET and Cockcroft-Walton multiplier circuit as high voltage DC source
Sulaeman, M. Y.; Widita, R.
Purpose: Non-ionizing radiation therapy for cancer using pulsed electric field with high intensity field has become an interesting field new research topic. A new method using nanosecond pulsed electric fields (nsPEFs) offers a novel means to treat cancer. Not like the conventional electroporation, nsPEFs able to create nanopores in all membranes of the cell, including membrane in cell organelles, like mitochondria and nucleus. NsPEFs will promote cell death in several cell types, including cancer cell by apoptosis mechanism. NsPEFs will use pulse with intensity of electric field higher than conventional electroporation, between 20-100 kV/cm and with shorter duration of pulse than conventional electroporation. NsPEFs requires a generator to produce high voltage pulse and to achieve high intensity electric field with proper pulse width. However, manufacturing cost for creating generator that generates a high voltage with short duration for nsPEFs purposes is highly expensive. Hence, the aim of this research is to obtain the low cost generator design that is able to produce a high voltage pulse with nanosecond width and will be used for nsPEFs purposes. Method: Cockcroft-Walton multiplier circuit will boost the input of 220 volt AC into high voltage DC around 1500 volt and it will be combined by a series of power MOSFET as a fast switch to obtain a high voltage with nanosecond pulse width. The motivation using Cockcroft-Walton multiplier is to acquire a low-cost high voltage DC generator; it will use capacitors and diodes arranged like a step. Power MOSFET connected in series is used as voltage divider to share the high voltage in order not to damage them. Results: This design is expected to acquire a low-cost generator that can achieve the high voltage pulse in amount of -1.5 kV with falltime 3 ns and risetime 15 ns into a 50Ω load that will be used for nsPEFs purposes. Further detailed on the circuit design will be explained at presentation.
Nanosecond pulsed electric fields (nsPEFs) low cost generator design using power MOSFET and Cockcroft-Walton multiplier circuit as high voltage DC source
Energy Technology Data Exchange (ETDEWEB)
Sulaeman, M. Y.; Widita, R. [Department of Physics, Nuclear Physics and Biophysics Research Division, Faculty of Mathematics and Natural Science, Institut Teknologi Bandung, Bandung (Indonesia)
Purpose: Non-ionizing radiation therapy for cancer using pulsed electric field with high intensity field has become an interesting field new research topic. A new method using nanosecond pulsed electric fields (nsPEFs) offers a novel means to treat cancer. Not like the conventional electroporation, nsPEFs able to create nanopores in all membranes of the cell, including membrane in cell organelles, like mitochondria and nucleus. NsPEFs will promote cell death in several cell types, including cancer cell by apoptosis mechanism. NsPEFs will use pulse with intensity of electric field higher than conventional electroporation, between 20–100 kV/cm and with shorter duration of pulse than conventional electroporation. NsPEFs requires a generator to produce high voltage pulse and to achieve high intensity electric field with proper pulse width. However, manufacturing cost for creating generator that generates a high voltage with short duration for nsPEFs purposes is highly expensive. Hence, the aim of this research is to obtain the low cost generator design that is able to produce a high voltage pulse with nanosecond width and will be used for nsPEFs purposes. Method: Cockcroft-Walton multiplier circuit will boost the input of 220 volt AC into high voltage DC around 1500 volt and it will be combined by a series of power MOSFET as a fast switch to obtain a high voltage with nanosecond pulse width. The motivation using Cockcroft-Walton multiplier is to acquire a low-cost high voltage DC generator; it will use capacitors and diodes arranged like a step. Power MOSFET connected in series is used as voltage divider to share the high voltage in order not to damage them. Results: This design is expected to acquire a low-cost generator that can achieve the high voltage pulse in amount of −1.5 kV with falltime 3 ns and risetime 15 ns into a 50Ω load that will be used for nsPEFs purposes. Further detailed on the circuit design will be explained at presentation.
Self-consistent stationary MHD shear flows in the solar atmosphere as electric field generators
Nickeler, D H; Wiegelmann, T; Kraus, M
Magnetic fields and flows in coronal structures, for example, in gradual phases in flares, can be described by 2D and 3D magnetohydrostatic (MHS) and steady magnetohydrodynamic (MHD) equilibria. Within a physically simplified, but exact mathematical model, we study the electric currents and corresponding electric fields generated by shear flows. Starting from exact and analytically calculated magnetic potential fields, we solveid the nonlinear MHD equations self-consistently. By applying a magnetic shear flow and assuming a nonideal MHD environment, we calculated an electric field via Faraday's law. The formal solution for the electromagnetic field allowed us to compute an expression of an effective resistivity similar to the collisionless Speiser resistivity. We find that the electric field can be highly spatially structured, or in other words, filamented. The electric field component parallel to the magnetic field is the dominant component and is high where the resistivity has a maximum. The electric field ...
Printed Circuit Board Surface Finish and Effects of Chloride Contamination, Electric Field, and Humidity on Corrosion Reliability
Conseil-Gudla, Hélène; Jellesen, Morten S.; Ambat, Rajan
Corrosion reliability is a serious issue today for electronic devices, components, and printed circuit boards (PCBs) due to factors such as miniaturization, globalized manufacturing practices which can lead to process-related residues, and global usage effects such as bias voltage and unpredictable user environments. The investigation reported in this paper focuses on understanding the synergistic effect of such parameters, namely contamination, humidity, PCB surface finish, pitch distance, and potential bias on leakage current under different humidity levels, and electrochemical migration probability under condensing conditions. Leakage currents were measured on interdigitated comb test patterns with three different types of surface finish typically used in the electronics industry, namely gold, copper, and tin. Susceptibility to electrochemical migration was studied under droplet conditions. The level of base leakage current (BLC) was similar for the different surface finishes and NaCl contamination levels up to relative humidity (RH) of 65%. A significant increase in leakage current was found for comb patterns contaminated with NaCl above 70% to 75% RH, close to the deliquescent RH of NaCl. Droplet tests on Cu comb patterns with varying pitch size showed that the initial BLC before dendrite formation increased with increasing NaCl contamination level, whereas electrochemical migration and the frequency of dendrite formation increased with bias voltage. The effect of different surface finishes on leakage current under humid conditions was not very prominent.
Harvesting vibrational energy with liquid-bridged electrodes: thermodynamics in mechanically and electrically driven RC-circuits
Janssen, Mathijs; van Roij, René
We theoretically study a vibrating pair of parallel electrodes bridged by a (deformed) liquid droplet, which is a recently developed microfluidic device to harvest vibrational energy. The device can operate with various liquids, including liquid metals, electrolytes, as well as ionic liquids. We numerically solve the Young-Laplace equation for all droplet shapes during a vibration period, from which the time-dependent capacitance follows that serves as input for an equivalent circuit model. We first investigate two existing energy harvesters (with a constant and a vanishing bias potential), for which we explain an open issue related to their optimal electrode separations, which is as small as possible or as large as possible in the two cases, respectively. Then we propose a new engine with a time-dependent bias voltage, with which the harvested work and the power can be increased by orders of magnitude at low vibration frequencies and by factors 2-5 at high frequencies, where frequencies are to be compared to...
Preparation of hierarchical porous carbon from waste printed circuit boards for high performance electric double-layer capacitors
Du, Xuan; Wang, Li; Zhao, Wei; Wang, Yi; Qi, Tao; Li, Chang Ming
Renewable clean energy and resources recycling have become inevitable choices to solve worldwide energy shortages and environmental pollution problems. It is a great challenge to recycle tons of waste printed circuit boards (PCB) produced every year for clean environment while creating values. In this work, low cost, high quality activated carbons (ACs) were synthesized from non-metallic fractions (NMF) of waste PCB to offer a great potential for applications of electrochemical double-layer capacitors (EDLCs). After recovering metal from waste PCB, hierarchical porous carbons were produced from NMF by carbonization and activation processes. The experimental results exhibit that some pores were formed after carbonization due to the escape of impurity atoms introduced by additives in NMF. Then the pore structure was further tailored by adjusting the activation parameters. Roles of micropores and non-micropores in charge storage were investigated when the hierarchical porous carbons were applied as electrode of EDLCs. The highest specific capacitance of 210 F g-1 (at 50 mA g-1) and excellent rate capability were achieved when the ACs possessing a proper micropores/non-micropores ratio. This work not only provides a promising method to recycle PCB, but also investigates the structure tailoring arts for a rational hierarchical porous structure in energy storage/conversion.
Electrical principles 3 checkbook
Bird, J O
Electrical Principles 3 Checkbook aims to introduce students to the basic electrical principles needed by technicians in electrical engineering, electronics, and telecommunications.The book first tackles circuit theorems, single-phase series A.C. circuits, and single-phase parallel A.C. circuits. Discussions focus on worked problems on parallel A.C. circuits, worked problems on series A.C. circuits, main points concerned with D.C. circuit analysis, worked problems on circuit theorems, and further problems on circuit theorems. The manuscript then examines three-phase systems and D.C. transients
Optimizing the operating parameters of corona electrostatic separation for recycling waste scraped printed circuit boards by computer simulation of electric field.
Li, Jia; Lu, Hongzhou; Liu, Shushu; Xu, Zhenming
The printed circuit board (PCB) has a metal content of nearly 28% metal, including an abundance of nonferrous metals such as copper, lead, and tin. The purity of precious metals in PCBs is more than 10 times that of rich-content minerals. Therefore, the recycling of PCBs is an important subject, not only from the viewpoint of waste treatment, but also with respect to the recovery of valuable materials. Compared with traditional process the corona electrostatic separation (CES) had no waste water or gas during the process and it had high productivity with a low-energy cost. In this paper, the roll-type corona electrostatic separator was used to separate metals and nonmetals from scraped waste PCBs. The software MATLAB was used to simulate the distribution of electric field in separating space. It was found that, the variations of parameters of electrodes and applied voltages directly influenced the distribution of electric field. Through the correlation of simulated and experimental results, the good separation results were got under the optimized operating parameter: U=20-30 kV, L=L(1)=L(2)=0.21 m, R(1)=0.114, R(2)=0.019 m, theta(1)=20 degrees and theta(2)=60 degrees . PMID:17900802
S. Miller's Experiments in Modelling of Non-Equilibrium Conditions with Gas Electric Discharge Simulating Primary Atmosphere
Directory of Open Access Journals (Sweden)
Ignat Ignatov
Full Text Available In this paper are submited data on the possibility of applying the coronal gas discharge effect (CGDE in modeling non-equilibrium conditions with gas electric discharge simulating conditions occurying in the primary atmosphere (electric sparks, lightning imitating S. Miller's experiments. The physical basis and technique of visualization of gas discharge (GD glowing of water drops in alternating electric fields of high electrical voltage (5–30 kV and frequency (10–150 kHz, as well as the possible electrosynthesis of organic molecules from a mixture of inorganic substances as hydrogen (H2, methane (CH4, ammonia (NH3 and carbon monoxide (CO in aqueous solutions of water exposed under the electrical discharge, UV-radiation and thermal heating to t = +100 0C were examined. The colour coronal spectral gas discharge analysis was applied for investigation of water samples of various origin, the samples of hot mineral, sea and mountain water obtained from various water sources of Bulgaria.
49 CFR 236.720 - Circuit, common return.
... Circuit, common return. A term applied where one wire is used for the return of more than one electric circuit. ... 49 Transportation 4 2010-10-01 2010-10-01 false Circuit, common return. 236.720 Section...
Hydrogen influence on the electrical and optical properties of ZnO thin films grown under different atmospheres
Energy Technology Data Exchange (ETDEWEB)
Lorite, I., E-mail: firstname.lastname@example.com; Wasik, J.; Michalsky, T.; Schmidt-Grund, R.; Esquinazi, P.
In this work we studied the changes of the electrical and optical properties after hydrogen plasma treatment of polycrystalline ZnO thin films grown under different atmosphere conditions. The obtained results show that the gas used during the growth process plays an important role in the way hydrogen is incorporated in the films. The hydrogen doping can produce radiative and non-radiative defects that reduce the UV emission in ZnO films grown in oxygen atmosphere but it passivates defects created when the films are grown in nitrogen atmosphere. Impedance spectroscopy measurements show that these effects are related to regions where hydrogen is mostly located, either at the grain cores or boundaries. We discuss how hydrogen strongly influences the initial semiconducting behavior of the ZnO thin films. - Highlights: • Effectiveness of hydrogen treatment depends on the thin film growth conditions. • There is no detection of secondary phases after treatment by IS. • Hydrogen incorporation changes optical and electrical ZnO properties.
Using an optical fibre anemometer to measure the speed of the electric wind in a negative polarity, atmospheric corona discharge
Energy Technology Data Exchange (ETDEWEB)
Hooper, A; Lamb, D W [Physics and Electronics, School of Biological, Biomedical and Molecular Sciences, University of New England, Armidale, NSW 2351 (Australia)
Coronas are partial discharges that occur in regions of non-uniform electric fields adjacent to conductors stressed to high voltages. Negative, Trichel-pulse coronas in air occur when a dc, negative-polarity, high voltage is applied to a conductor. Trichel pulses in atmospheric air generate significant amounts of ozone as well as electrical and acoustic noise. Under the right conditions these coronas can be a precursor to complete electrical breakdown of the air gap due to a reduction in the density of neutral molecules resulting from a combination of localised heating and convective air flow generated by the movement of negative ions. An optical fibre anemometer, based on a Mach-Zehnder interferometer has been constructed to measure the speed of the wind generated in the point-plane gap of a negative, Trichel-pulse corona discharge in atmospheric air. The sensing arm of the fibre interferometer is subjected to controlled, repetitive bursts of infrared radiation from a CO{sub 2} laser and the combination of localised heating and convective cooling by the corona wind results in fringe shifts which are directly calibrated to the speed of the wind. This paper reports on the nature of the calibration process and presents some radial profiles of wind speed in the corona gap.
Using an optical fibre anemometer to measure the speed of the electric wind in a negative polarity, atmospheric corona discharge
International Nuclear Information System (INIS)
Coronas are partial discharges that occur in regions of non-uniform electric fields adjacent to conductors stressed to high voltages. Negative, Trichel-pulse coronas in air occur when a dc, negative-polarity, high voltage is applied to a conductor. Trichel pulses in atmospheric air generate significant amounts of ozone as well as electrical and acoustic noise. Under the right conditions these coronas can be a precursor to complete electrical breakdown of the air gap due to a reduction in the density of neutral molecules resulting from a combination of localised heating and convective air flow generated by the movement of negative ions. An optical fibre anemometer, based on a Mach-Zehnder interferometer has been constructed to measure the speed of the wind generated in the point-plane gap of a negative, Trichel-pulse corona discharge in atmospheric air. The sensing arm of the fibre interferometer is subjected to controlled, repetitive bursts of infrared radiation from a CO2 laser and the combination of localised heating and convective cooling by the corona wind results in fringe shifts which are directly calibrated to the speed of the wind. This paper reports on the nature of the calibration process and presents some radial profiles of wind speed in the corona gap
Computing Electric Currents in the Martian Ionosphere Using Magnetometer Data from the Mars Atmospheric Volatile EvolutioN (MAVEN) Spacecraft
Fogle, A. L.
Mars does not have a global magnetic field like Earth does. However, due to solar wind and interplanetary magnetic field (IMF) interactions, electric currents are induced which create an induced magnetosphere. As MAVEN passes through the ionosphere of Mars, the magnetometer on board continuously measures the induced magnetic field in the ionosphere. Using Ampere's Law (∇ × B = µ0j) along with these measurements of the induced magnetic field, we can quantify the electric currents in the ionosphere. We are particularly interested in magnetic field profiles that have a radial component that is less than or equal to 5 nanoteslas in magnitude. By only using measurements where the radial component of the magnetic field satisfies the aforementioned condition and assuming that there are no horizontal gradients in the magnetic field, we will calculate horizontal currents in the ionosphere. Using these calculated currents, we will analyze altitudinal variations in magnitude and direction of the currents. Measuring these horizontal currents can give us insights into how the solar wind and IMF can affect the upper atmosphere of Mars. For example, induced electric currents can cause Joule heating in the atmosphere, which can potentially modify its neutral dynamics.
An assessment of alternatives for replacing Freon 113 in bench type electrical circuit board cleaning at Fermi National Accelerator Laboratory
International Nuclear Information System (INIS)
Fermilab is presently phasing out all solvents containing Freon-113 (CFC-113) as part of the continuing Waste Minimization Program. These solvents are used primarily in cleaning the flux off of electronic circuit boards after soldering, specifically in bench type work. Title VI of the Clean Air Act mandates a production phase-out for ozone depleting substances, like CFC-113, by the year 2000. Our study addresses this issue by evaluating and choosing alternative non-CFC solvents to replace the CFC-1 13 solvents at Fermilab. Several potential non-CFC cleaning solvents were tested. The evaluation took place in three parts: controlled experimental evaluation, chemical composition evaluation, and employee performed evaluation. First, we performed a controlled nine-step procedure with the potential solvents where each was evaluated in categories such as cleaning effectiveness, odor, residue, type of output and drying time. Next, we listed the chemical composition of each solvent. We noted which solvents contained hydrochlorofluorocarbons because they are targeted for phase-out in the future and will be recognized as interim solutions only. Finally, after preliminary testing, five solvents were chosen as the best options. These solvents were sent to be tested by Fermilab employees who use such materials. Their opinions are valuable not only because they are knowledgeable in this field, but also because they will be using the solvents chosen to replace the CFC-113 solvents. The results favored two ''best alternatives'': Safezone Solvent Flux Remover by Miller-Stephenson and E-Series CFC Free Flux-Off 2000 by Chemtech. Another possible solution also pursued is the no-clean solder option. In our study, we were not able to thoroughly investigate the many types of no-clean solders because of time and financial constraints. The testing that was done, however, showed that no-clean solder was a viable alternative in many cases
Power spectrum features of the near-Earth atmospheric electric field in Kamchatka
Directory of Open Access Journals (Sweden)
S. E. Smirnov
Full Text Available Power spectrum of the diurnal variations of the quasi-electrostatic field Ez in the near-Earth atmosphere have been presented for the first time. The Ez power spectrum variations in the period of fine weather have been shown to exhibit two bands of the periods of natural atmospheric oscillations with T = 1-5 and 6-24 h. These oscillations are the modes of the internal gravity and tidal waves in the lower atmosphere. On the days under atmospheric precipitation, the spectral power of Ez increases by an order of magnitude. During the pre-earthquake period, when the diurnal Ez variation had an anomaly, the intensity of harmonics with T = 1.8, 2.2, and 3.8 h increased by an order of magnitude or more in comparison with the Ez spectra in fine weather. Two additional spectral bands with T = 0.6 and 1 h have appeared simultaneously.
Mass and elemental distributions of atmospheric particles nearby blast furnace and electric arc furnace operated industrial areas in Australia.
Mohiuddin, Kazi; Strezov, Vladimir; Nelson, Peter F; Stelcer, Eduard; Evans, Tim
The improved understanding of mass and elemental distributions of industrial air particles is important due to their heterogeneous atmospheric behaviour and impact on human health and the environment. In this study, particles of different size ranges were collected from three sites in Australia located in the vicinity of iron and steelmaking industries and one urban background site with very little industrial influence. In order to determine the importance of the type of industrial activity on the urban atmospheric quality, the industrial sites selected in this study were in the close proximity to two blast furnace operated and one electric arc furnace based steelmaking sites. The chemical compositions of the collected air particles were analysed using the proton induced X-ray emission (PIXE) technique. This study revealed significantly higher metal concentrations in the atmospheric particles collected in the industrial sites, comparing to the background urban site, demonstrating local influence of the industrial activities to the air quality. The modality types of the particles were found to be variable between the mass and elements, and among elements in the urban and industrial areas indicating that the elemental modal distribution is as important as particle mass for particle pollution modelling. The highest elemental number distribution at all studied sites occurred with particle size of 0.1 μm. Iron was found as the main dominant metal at the industrial atmosphere in each particle size range. The industrial Fe fraction in the submicron and ultrafine size particles was estimated at up to 95% which may be released from high temperature industrial activities with the iron and steelmaking industries being one of the major contributors. Hence, these industrial elemental loadings can highly influence the atmospheric pollution at local urban and regional levels and are required to consider in the atmospheric modelling settings.
A Van de Graaf source mechanism for middle atmospheric vertical electric fields
Aikin, A. C.; Maynard, N. C.
It is proposed that meteoric and other debris descending through the mesosphere constitute a natural Van de Graaf generator for vertical electric fields within the mesosphere. Dust and aerosol particles falling from above 85 km are charged negatively in the upper D-region. Charge is lost in the region below 70 km. This net charge transport creates a vertical polarization electric field. Calculated fields are in the range of 10 mV/m for the average input of meteoric debris. Observed vertical electric fields are confined to a few occasions when large fields of the order of 4 V/m are observed to maximize at 65 km. Calculated fields from this model also maximize at this altitude, but a special event with increased dust density or another mechanism to increase relative vertical velocity is required to explain the large fields. Such large values are the exception rather than the rule for D-region vertical electric fields.
Electrical Characteristics of Dielectric-Barrier Discharges in Atmospheric Pressure Air Using a Power-Frequency Voltage Source
Institute of Scientific and Technical Information of China (English)
TAO Xiaoping; LU Rongde; LI Hui
Dielectric-barrier discharges (DBDs) in atmospheric pressure air have been studied by using a power-frequency voltage source. In this paper the electrical characteristics of DBDs us- ing glass and alumina dielectrics have been investigated experimentally. According to the Lissajous figures of voltage-charges, it is discovered that the discharge power for an alumina dielectric is much higher than that for a glass dielectric at the same applied voltage. Also~ the voltage-current curves of the glass and alumina dielectrics confirm the fact that the dielectric barriers behave like semiconducting materials at certain applied voltages.
Transport of the smoke plume from Chiado's fire in Lisbon (Portugal) sensed by atmospheric electric field measurements
Conceição, Ricardo; Melgão, Marta; Silva, Hugo G.; Nicoll, Keri; Harrison, Richard G.; Reis, António H.
The Chiado's fire that affected the city centre of Lisbon (Portugal) occurred on 25th August 1988 and had a significant human and environmental impact. This fire was considered the most significant hazard to have occurred in Lisbon city centre after the major earthquake of 1755. A clear signature of this fire is found in the atmospheric electric field data recorded at Portela meteorological station about 8 km NE from the site where the fire started at Chiado. Measurements were made using a Be...
Experimental Research on Atmospheric Electric Field and Extensive Air Shower Particle Increasing During Thunderstorms with ARGO-YBJ
Institute of Scientific and Technical Information of China (English)
XU Bin; ZHANG Ying; JIA Huan-Yu
From April lst to August 14th, 2006, thunderstorms had been recorded at Yangbajing Cosmic Ray Observatory by ARGO-YBJ experiment. This paper analyzed the correlation between atmospheric electric field (AEF) and "scaler mode" counting rate during thunderstorm. Counting rates of multiplicities n = 1,2 were found to have a large increase ( from 1.02% to 9.03% ), while there was few or no changes in those of multiplicities n =3 and n≥4 during the thunderstorms. The counts of different multiplicities had different feedbacks on the violent change of AEF, which showed that their energy and most components were distinguishing.
Integrated coherent matter wave circuits
International Nuclear Information System (INIS)
An integrated coherent matter wave circuit is a single device, analogous to an integrated optical circuit, in which coherent de Broglie waves are created and then launched into waveguides where they can be switched, divided, recombined, and detected as they propagate. Applications of such circuits include guided atom interferometers, atomtronic circuits, and precisely controlled delivery of atoms. We report experiments demonstrating integrated circuits for guided coherent matter waves. The circuit elements are created with the painted potential technique, a form of time-averaged optical dipole potential in which a rapidly moving, tightly focused laser beam exerts forces on atoms through their electric polarizability. Moreover, the source of coherent matter waves is a Bose-Einstein condensate (BEC). Finally, we launch BECs into painted waveguides that guide them around bends and form switches, phase coherent beamsplitters, and closed circuits. These are the basic elements that are needed to engineer arbitrarily complex matter wave circuitry
A better method to define electrical chargeability from laboratory measurements of spectral impedance using a parallel Cole-Cole equivalent circuit
Enkin, R. J.
Induced polarization (IP) is a successful electric method to identify drill targets for mineral exploration at the property scale. The Paleomagnetism and Petrophysics Laboratory at the Geological Survey of Canada makes petrophysical measurements on cylindrical rock samples, 2.5 cm diameter and 2.2 cm long. This small size has advantages, including allowing measurement of magnetic remanence with standard paleomagnetism equipment, but it is too small to allow a 4-contact electrical impedance measurement. The samples are impregnated with distilled water under vacuum and allowed 24 hours for solutes to dissolve off pore walls, in order to approximate original groundwater ionic conductivity. We use graphite electrodes on the flat surfaces and measure the complex impedance at 5 frequencies per decade from 1 MHz down to 25 mHz. Typical responses on a Cole-Cole plot (i.e., real vs. imaginary components displayed parametrically as a function of frequency) look like a two overlapping circular arcs followed by a constant-phase diffusive response at lowest frequencies. The impedance frequency response is fit with a circuit in which the rock is modelled as a set of parallel resistor and constant-phase-element pathways, connected in series through a modified constant-phase-element representing the low frequency sample-holder response. The program "ZarcFit", written in LabView, allows the operator to tune parameters of an equivalent but far more intuitive series circuit with a set of 13 sliders, and then perform a least-squares optimization. Time domain chargeability is defined by removing the effect of the sample holder, taking the Fourier transform to convert the frequency response to its time-domain equivalent and then integrating under the resulting voltage-decay curve. Time domain measurements using two-electrode sample holders are necessarily contaminated by the low-frequency response of ionic diffusion at the electrodes. Results are compiled in the Canadian Rock Physical
Layout of Controller Switch Circuit of Power Driver of Electric Motor Car%电动车电机控制器功率驱动开关电路设计方案
Institute of Scientific and Technical Information of China (English)
The performance of electric motor car depends on the design of electric motor controller. The switch circuit of power driver is the important module of the entire controller. Its design will directly determine the running state of electric motor car.%电动车性能的优劣取决于电机控制器的整体设计方案,而功率驱动开关电路则是整个控制器的重要组成模块,它的设计将直接决定车辆的运行状态。
Meteorological influences on atmospheric radioactivity and its effects on the electrical environment
International Nuclear Information System (INIS)
The 222Rn content of soil gas is influenced by meteorological parameters and especially by wind speed. For 220Rn the effects are less pronounced. The exhalation of 220Rn is dependent on precipitation and atmospheric turbulence. From horizontal measurements of radioactivity in the air, the most representative values are obtained under unstable, near-neutral, and light stable stratifications. The concentration of natural radioactivity at a point in the atmospheric surface layer can be expressed in terms of atmospheric stability if the horizontal distributions are fairly homogeneous. For longtime variations of radioactivity in the air, the precipitation and groundwater conditions are of prime concern. But for the rapid fluctuations the turbulent processes give the main contribution to the variations
Demonstrations with an "LCR" Circuit
Kraftmakher, Yaakov
The "LCR" circuit is an important topic in the course of electricity and magnetism. Papers in this field consider mainly the forced oscillations and resonance. Our aim is to show how to demonstrate the free and self-excited oscillations in an "LCR" circuit. (Contains 4 figures.)
Analysis of atmospheric aerosols by atomic emission spectrometry with electrical discharge sampling
International Nuclear Information System (INIS)
A procedure is developed for the determination of the concentration of heavy metals (Pb, Mn, Cu, Ni, Zn, and Cd) in atmospheric air by atomic emission spectrometry with gas-discharge sampling onto the end of a standard carbon electrode. A design of a two-section sampler is proposed; the sampler provides the rapid determination of deposition factors for the deposition of heavy metals contained in aerosol particles onto the end of a carbon electrode. Examples of determining metal concentrations in a model sample of air and in atmospheric air and determination limits of metals deposited onto the end of a carbon electrode are given
An overview of the lightning and atmospheric electricity observations collected in southern France during the HYdrological cycle in Mediterranean EXperiment (HyMeX), Special Observation Period 1
Defer, E.; Pinty, J.-P.; S. Coquillat; Martin, J.-M.; S. Prieur; S. Soula; E. Richard; Rison, W.; P. Krehbiel; Thomas, R; D. Rodeheffer; Vergeiner, C.; F. Malaterre; S. Pedeboy; SCHULZ, W
The PEACH project (Projet en Electricité Atmosphérique pour la Campagne HyMeX – the Atmospheric Electricity Project of the HyMeX Program) is the atmospheric electricity component of the Hydrology cycle in the Mediterranean Experiment (HyMeX) experiment and is dedicated to the observation of both lightning activity and electrical state of continental and maritime thunderstorms in the area of the Mediterranean Sea. During the HyMeX SOP1 (Special Observation Period) from 5 Sept...
A one-dimensional model of the atmospheric electric field near the Venusian surface
Tzur, I.; Levin, Z.
A one-dimensional model is developed for the development of an electric field below the Venus cloud layer, assuming an absence of cloud-to-ground lightning. The ion-bearing medium is considered as a collision dominated, partially ionized gas. Ion production by cosmic rays is accompanied by a sink of recombining positive and negative ions. The net diffusion of ions to the surface was examined, and modeled as resulting from differences between the ion diffusivities and electrical activity within the clouds. Calculations were made of the conduction and diffusion currents profiles, positive and negative ion densities, and the net space charge. Higher positive ion diffusivity was found to enhance the surface positive charge, producing an electric field which depended on the boundary layer mixing. Charge separation in the clouds also produces an electric field. Assuming a fair weather conduction current similar to earth leads to an electric field of 5 kV/sq m at the surface, with continuity to a few kilometers altitude.
A comparison of gold versus silver electrode contacts for high-resolution gastric electrical mapping using flexible printed circuit board arrays
International Nuclear Information System (INIS)
Stomach contractions are initiated and coordinated by electrical events termed slow waves, and slow wave abnormalities contribute to gastric motility disorders. Recently, flexible printed circuit board (PCB) multi-electrode arrays were introduced, facilitating high-resolution mapping of slow wave activity in humans. However PCBs with gold contacts have shown a moderately inferior signal quality to previous custom-built silver-wire platforms, potentially limiting analyses. This study determined if using silver instead of gold contacts improved flexible PCB performance. In a salt-bath test, modestly higher stimulus amplitudes were recorded from silver PCBs (mean 312, s.d. 89 µV) than those from gold (mean 281, s.d. 85 µV) (p < 0.001); however, the signal-to-noise ratio (SNR) was similar (p = 0.26). In eight in vivo experimental studies, involving gastric serosal recordings from five pigs, no silver versus gold differences were found in terms of slow wave amplitudes (mean 677 versus 682 µV; p = 0.91), SNR (mean 8.8 versus 8.8 dB; p = 0.94) or baseline drift (NRMS; mean 12.0 versus 12.1; p = 0.97). Under the prescribed conditions, flexible PCBs with silver or gold contacts provide comparable results in vivo, and contact material difference does not explain the performance difference between current-generation slow wave mapping platforms. Alternative explanations for this difference and the implications for electrode design are discussed. (note)
Electric Conductivity And Waves In The Atmosphere Of Titan From The Pwa-hasi Instrument On The Huygens Probe
Hamelin, Michel; Brown, V. J.; Béghin, C.; Chabassière, M.; Falkner, P.; Ferri, F.; Fulchignoni, M.; Grard, R.; Hofe, R.; Jernej, I.; Lara, L.; Lopez-Moreno, J. J.; Molina-Cuberos, G.; Rodrigo, R.; Schwingenschuh, K.; Simoes, F.; Trautner, R.
The descent of the HUYGENS Probe and landing on Titan during the CASSINI-HUYGENS mission (NASA/ESA/ASI) provided outstanding discoveries. Penetrating under the ionospheric top layer, HUYGENS revealed Titan's atmospheric electricity characteristics that were unaccessible from remote sensing even from the CASSINI orbiter. The Permittivity, Waves and Altimetry (PWA) analyser is a subsystem of HASI (HUYGENS Atmospheric Structure Instrument), an instrument built by a group of european laboratories. This versatile instrument measures the conductivity of the atmosphere with two complementary sensors, a mutual impedance (MI) probe and a relaxation probe (RP) that measures also DC and AC electric fields in passive mode. The preliminary results revealed the lower ionosphere peak of electron density at the altitude of 60 km deduced from our MI and RP measurements, but these results were only qualitative as several difficulties were found in the data analysis procedures. The present work shows the revised procedures deduced from new detailed models and new laboratory tests with spare instruments. In particular the new analysis includes Probe velocity effects, space charge around electrodes, and other minor effects. Electromagnetic waves data in the ranges 0-100 Hz and 0-10 kHz are analysed to search for clues of lightning activity on Titan and possible Schumann resonances. The origin of the high level 36 Hz detected signal, wether natural or artificial, is discussed. The authors acknowledge ASI, CNES, ESTEC, Spanish and Austrian space agencies, which supported the PWA-HASI instrument development and ISSI, Bern, which provided facilities to perform the present work.
Characteristics of meter-scale surface electrical discharge propagating along water surface at atmospheric pressure
Hoffer, Petr; Sugiyama, Yuki; Hosseini, S. Hamid R.; Akiyama, Hidenori; Lukes, Petr; Akiyama, Masahiro
This paper reports physical characteristics of water surface discharges. Discharges were produced by metal needle-to-water surface geometry, with the needle electrode driven by 47 kV (FWHM) positive voltage pulses of 2 µs duration. Propagation of discharges along the water surface was confined between glass plates with 2 mm separation. This allowed generation of highly reproducible 634 mm-long plasma filaments. Experiments were performed using different atmospheres: air, N2, and O2, each at atmospheric pressure. Time- and spatially-resolved spectroscopic measurements revealed that early spectra of discharges in air and nitrogen atmospheres were dominated by N2 2nd positive system. N2 radiation disappeared after approx. 150 ns, replaced by emissions from atomic hydrogen. Spectra of discharges in O2 atmosphere were dominated by emissions from atomic oxygen. Time- and spatially-resolved emission spectra were used to determine temperatures in plasma. Atomic hydrogen emissions showed excitation temperature of discharges in air to be about 2 × 104 K. Electron number densities determined by Stark broadening of the hydrogen H β line reached a maximum value of ~1018 cm-3 just after plasma initiation. Electron number densities and temperatures depended only slightly on distance from needle electrode, indicating formation of high conductivity leader channels. Direct observation of discharges by high speed camera showed that the average leader head propagation speed was 412 km · s-1, which is substantially higher value than that observed in experiments with shorter streamers driven by lower voltages.
Fire protection electrical engineering
Energy Technology Data Exchange (ETDEWEB)
Oh, Jung Min
This book concentrates of electricity with current, voltage, power, ohms law, access of resistance, electrolytic analysis and battery, static on frictional electricity and electrostatic induction, coulomb's law, Gauss's law, condenser and capacity, magmatism on magnetic field and magnetic line of force, magnetic circuit, electromagnetic force, electromotive current, basic alternating current circuit, circuit network analysis, three-phase current, non-sinusoidal alternating current, transient phenomena, semiconductor, electric measurement on measurement over resistance, power, power rate and circuit tester, automatic control on introduction, term, classification, foundation of sequence control, logic circuit and basic logic circuit and electric equipment.
Spatial distribution of the electrical potential and ion concentration in the downstream area of atmospheric pressure remote plasma
Directory of Open Access Journals (Sweden)
M. V. Mishin
Full Text Available This paper presents the results from an experimental study of the ion flux characteristics behind the remote plasma zone in a vertical tube reaction chamber for atmospheric pressure plasma enhanced chemical vapor deposition. Capacitively coupled radio frequency plasma was generated in pure He and gas mixtures: He–Ar, He–O2, He–TEOS. We previously used the reaction system He–TEOS for the synthesis of self-assembled structures of silicon dioxide nanoparticles. It is likely that the electrical parameters of the area, where nanoparticles have been transported from the synthesis zone to the substrate, play a significant role in the self-organization processes both in the vapor phase and on the substrate surface. The results from the spatial distribution of the electrical potential and ion concentration in the discharge downstream area measured by means of the external probe of original design and the special data processing method are demonstrated in this work. Positive and negatives ions with maximum concentrations of 106–107 cm−3 have been found at 10–80 mm distance behind the plasma zone. On the basis of the revealed distributions for different gas mixtures, the physical model of the observed phenomena is proposed. The model illustrates the capability of the virtual ion emitter formation behind the discharge gap and the presence of an extremum of the electrical potential at the distance of approximately 10−2–10−1 mm from the grounded electrode.
Effects of annealing atmosphere on crystallization and electrical properties in BiFeO3 thin films by chemical solution deposition(CSD)
International Nuclear Information System (INIS)
BiFeO3 (BFO) thin films have been prepared on platinized silicon substrates by chemical solution deposition (CSD) and annealed at 600 .deg. C for 1 hour under various atmospheres, i.e., O2, Air and N2. Effects of annealing atmospheres on the crystallization and electrical properties of BFO films were investigated. Crystallization behavior and electrical properties of BFO films depend on the oxygen partial pressure of the annealing atmosphere. The BFO thin film annealed in N2 atmosphere showed a good crystallinity. The surface roughness of the BFO film decreased with lowering oxygen partial pressure of the annealing atmosphere. Low leakage current density and P-E hysteresis were found only in the BFO film annealed at 600 .deg. C under N2 atmosphere. Leakage current density, polarization (at zero electric field) and electric field (at zero polarization) of the BFO film annealed at 600 .deg. C under N2 are 5 x 10-7 A/cm2 at 1 V, 0.2 μC/cm2 and 15kV/cm, respectively
Mass and elemental distributions of atmospheric particles nearby blast furnace and electric arc furnace operated industrial areas in Australia
Energy Technology Data Exchange (ETDEWEB)
Mohiuddin, Kazi, E-mail: firstname.lastname@example.com [Graduate School of the Environment, Department of Environment and Geography, Faculty of Science, Macquarie University, NSW (Australia); Strezov, Vladimir; Nelson, Peter F. [Graduate School of the Environment, Department of Environment and Geography, Faculty of Science, Macquarie University, NSW (Australia); Stelcer, Eduard [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Evans, Tim [Graduate School of the Environment, Department of Environment and Geography, Faculty of Science, Macquarie University, NSW (Australia)
The improved understanding of mass and elemental distributions of industrial air particles is important due to their heterogeneous atmospheric behaviour and impact on human health and the environment. In this study, particles of different size ranges were collected from three sites in Australia located in the vicinity of iron and steelmaking industries and one urban background site with very little industrial influence. In order to determine the importance of the type of industrial activity on the urban atmospheric quality, the industrial sites selected in this study were in the close proximity to two blast furnace operated and one electric arc furnace based steelmaking sites. The chemical compositions of the collected air particles were analysed using the proton induced X-ray emission (PIXE) technique. This study revealed significantly higher metal concentrations in the atmospheric particles collected in the industrial sites, comparing to the background urban site, demonstrating local influence of the industrial activities to the air quality. The modality types of the particles were found to be variable between the mass and elements, and among elements in the urban and industrial areas indicating that the elemental modal distribution is as important as particle mass for particle pollution modelling. The highest elemental number distribution at all studied sites occurred with particle size of 0.1 μm. Iron was found as the main dominant metal at the industrial atmosphere in each particle size range. The industrial Fe fraction in the submicron and ultrafine size particles was estimated at up to 95% which may be released from high temperature industrial activities with the iron and steelmaking industries being one of the major contributors. Hence, these industrial elemental loadings can highly influence the atmospheric pollution at local urban and regional levels and are required to consider in the atmospheric modelling settings. - Highlights: • Urban and
49 CFR 236.731 - Controller, circuit.
... 49 Transportation 4 2010-10-01 2010-10-01 false Controller, circuit. 236.731 Section 236.731 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Controller, circuit. A device for opening and closing electric circuits....
49 CFR 236.726 - Circuit, track.
... 49 Transportation 4 2010-10-01 2010-10-01 false Circuit, track. 236.726 Section 236.726 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Circuit, track. An electrical circuit of which the rails of the track form a part....
30 CFR 56.6407 - Circuit testing.
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Circuit testing. 56.6407 Section 56.6407... Blasting § 56.6407 Circuit testing. A blasting galvanometer or other instrument designed for testing blasting circuits shall be used to test each of the following: (a) Continuity of each electric detonator...
30 CFR 75.1323 - Blasting circuits.
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Blasting circuits. 75.1323 Section 75.1323... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1323 Blasting circuits. (a) Blasting circuits shall be protected from sources of stray electric current. (b) Detonators made...
Atmospheric electric field anomalies associated with solar flare/coronal mass ejection events and solar energetic charged particle "Ground Level Events"
Directory of Open Access Journals (Sweden)
E. A. Kasatkina
Full Text Available We discuss the fair weather atmospheric electric field signatures of three major solar energetic charged particle events which occurred in on 15 April 2001, 18 April and 4 November, and their causative solar flares/coronal mass ejections (SF/CMEs. Only the 15 April 2001 shows clear evidence for Ez variation associated to SF/CME events and the other two events may support this hypothesis as well although for them the meteorological data were not available. All three events seem to be associated with relativistic solar protons (i.e. protons with energies >450 MeV of the Ground Level Event (GLE type. The study presents data on variations of the vertical component of the atmospheric electric field (Ez measured at the auroral station Apatity (geomagnetic latitude: 63.8°, the polar cap station Vostok (geomagnetic latitude: −89.3° and the middle latitude stations Voyeikovo (geomagnetic latitude: 56.1° and Nagycenk (geomagnetic latitude: 47.2°. A significant disturbance in the atmospheric electric field is sometimes observed close to the time of the causative solar flare; the beginning of the electric field perturbation at Apatity is detected one or two hours before the flare onset and the GLE onset. Atmospheric electric field records at Vostok and Voyeikovo show a similar disturbance at the same time for the 15 April 2001 event. Some mechanisms responsible for the electric field perturbations are considered.
Electrical and electronic principles
Knight, SA
Electrical and Electronic Principles, 3 focuses on the principles involved in electrical and electronic circuits, including impedance, inductance, capacitance, and resistance.The book first deals with circuit elements and theorems, D.C. transients, and the series circuits of alternating current. Discussions focus on inductance and resistance in series, resistance and capacitance in series, power factor, impedance, circuit magnification, equation of charge, discharge of a capacitor, transfer of power, and decibels and attenuation. The manuscript then examines the parallel circuits of alternatin
Electrical Characterization of Dielectric Barrier Discharge in Atmospheric Air for Plasma Production Aiming for Improving Seed Germination
International Nuclear Information System (INIS)
A Dielectric Barrier Discharge (DBD) reactor has been developed aiming for improving seed germination. This DBD reactor consists of two 3-inch stainless steel planar electrodes with mylar sheets as dielectric barriers. An adjustable frequency AC high voltage power supply is then connected to the DBD reactor in order to generate plasma. The gas gap of DBD can be varied up to 3 mm when operating in atmospheric air. The electrical characterization of this DBD such as power, current, etc., together with optical emission characterization of plasma generated with this DBD will be presented. This information will be essential toward a development in order for applying plasma to small seeds, such as tomato, rice, chili, etc. to improve seed germination as inspired by the work of Bozena Sera et al (IEEE Trans. Plasma Sci., vol. 38, no. 10, p.2963).
Atmospheric corrosion Monitoring with Time-of-Wetness (TOW) sensor and Thin Film Electric Resistance (TFER) sensor
International Nuclear Information System (INIS)
In this study, TOW sensor was fabricated with the same P. J. Serada's in NRC and was evaluated according to pollutant amount and wet/dry cycle. Laboratorily fabricated thin film electric resistance (TFER) probes were applied in same environment for the measurement of corrosion rate for feasibility. TOW sensor could not differentiate the wet and dry time especially at polluted environment like 3.5% NaCl solution. This implies that wet/dry time monitoring by means of TOW sensor need careful application on various environment. TFER sensor could produce instant atmospheric corrosion rate regardless of environment condition. And corrosion rate obtained by TFER sensor could be differentiated according to wet/dry cycle, wet/dry cycle time variation and solution chemistry. Corrosion behaviors of TFER sensor showed that corrosion could proceed even after wet cycle because of remained electrolyte at the surface
Digital circuit boards mach 1 GHz
Morrison, Ralph
A unique, practical approach to the design of high-speed digital circuit boards The demand for ever-faster digital circuit designs is beginning to render the circuit theory used by engineers ineffective. Digital Circuit Boards presents an alternative to the circuit theory approach, emphasizing energy flow rather than just signal interconnection to explain logic circuit behavior. The book shows how treating design in terms of transmission lines will ensure that the logic will function, addressing both storage and movement of electrical energy on these lines. It cove
Effect of Antihypertensive Errors of Secondary Circuit Voltage on the Electric Power Metering%电压二次回路压降误差对供电线路电能计量的影响
Institute of Scientific and Technical Information of China (English)
电能计量装置由电能表、电流电压互感器及其二次回路构成。电能计量装置的综合误差包括:电能表的误差r0、互感器的合成误差着P、电压互感器二次回路电压降引起的合成误差rd。因此,电能计量装置的综合误差为:r=r0+着P+rd(豫)。%Electric energy metering device is constituted of Watt-hour meter, electric current and voltage transformer and secondary circuit. The composite error of electric energy metering comes from error of electric energy meter (r0), combination of transformer (εP), the voltage decrease from secondary circuit of voltage transformer (rd). As a result, the composite error of electric energy metering device is:r=r0+εP+rd (%).
Circuito eléctrico equivalente de una vesícula sináptica Electric Circuit Equivalent to a Synaptic Vesicle
Directory of Open Access Journals (Sweden)
Cortés Xaira
Full Text Available En el presente trabajo se desarrolla un modelo eléctrico de uno de los elementosprimordiales en la sinapsis nerviosa: la vesícula sináptica. Dicha vesícula se consideracomo un organelo esferoidal, despojada de neurotransmisores y se asume, además, quesu lumen, su membrana y el citoplasma neuronal se comportan como medios lineales,homogéneos e isotrópicos caracterizados por conductividades y permitividades especí-ficas. El método utilizado será la aplicación teórica de un campo eléctrico (que varía enel tiempo a bajas frecuencias sobre esta vesícula, lo que induce a través de su membra-na una diferencia de potencial cuya caracterización se obtiene a partir de las ecuacionesde Maxwell sometidas a condiciones de contorno adecuadas, en la denominada aproxi-mación cuasi-estacionaria. A su vez, mediante aplicación de la Transformada de Laplacea las expresiones resultantes se obtiene la FUNCIÓN DE TRANSFERENCIA, que condu-ce a sintetizar un circuito RLC equivalente de la vesícula en estudio. El modelo predicevalores de capacitancia para vesículas esféricas individuales que, al ser contrastados conlos que presenta la literatura existente derivada de procesos experimentales previos,alienta la perseverancia en este enfoque teórico germinal.In the present work an electrical model of the synaptic vesicle is developed. The vesicleis considered as a spheroidal organelle without neurotransmitters in its inner space. Inaddition, its lumen, its membrane and the neuronal cytoplasm behave like linear,homogenous and isotropic media characterized by specific conductivities and permi-tivities. The theoretical approach considers the application of an electric field (varying intime at low frequencies on this vesicle. A transmembrane potential difference is inducedand its characterization is obtained from Maxwell's equations subject to appropriateboundary conditions, in the so-called quasi-stationary approach. By applying theLaplace Transform to
Optimal design of an atmospheric water generator (AWG) based on thermo-electric cooler (TEC) for drought in rural area
Suryaningsih, Sri; Nurhilal, Otong
Drinking water availability is a major issue in some rural area in Indonesia during the summer season due to lack of rainfall, which peoples in this area have to fetch the water a few kilometers away from home. The Atmospheric Water Generator (AWG) is one of the alternative solution for fresh water recovery from atmosphere which is directly condensed the moisture content of water vapor from the air. This paper presents the method to develop a prototype of an AWG based on Thermo-electric cooler (TEC) that used 12 Volt DC, hence its suitability for using renewable energy resource. Computational Fluid Dynamics (CFD) is utilized to optimize the design process in the flow region only, it's not suitable for recent CFD software to use in Multi physics, because inaccuracy, cost and time saving. Some parameters such as temperature, moisture content, air flow, pressure, form of air flow channel and the water productivity per unit input of energy are to be considered. The result is presented as an experimental prototype of an AWG based on TEC and compared with other conventional commercial products.
Behaviour of non-metallic inclusions during electric-arc heating in argon-hydrogen atmosphere
International Nuclear Information System (INIS)
Conditions of steel refining by a high-temperature hydrogen-containing gas are studied experimentally. Armco-iron with different content of silicon or aluminium served as a source mareterial as well as corrosion resistant steel 12Kh18N10T. It permits to have in metals inclusions of a definite type (Al2O3; SiO2; TiN and others). Growth of alloy refining by oxygen and deoxidation products during electric - arc heating, when hydrogen being introduced into the inerti gas, is shown to be mainly connected with intensity rise in metal melt mixing during hydrogen boiling in case of iron remelting, deoxidized by aluminium, and with chemical interaction with hydrogen in case of iron remelting deoxidized bu silicon
Electrical and spectroscopic analysis of mono- and multi-tip pulsed corona discharges in air at atmospheric pressure
International Nuclear Information System (INIS)
This work is devoted to the analysis of experimental results obtained in dry air at atmospheric pressure in a positive point-to-plane corona discharge under a pulsed applied voltage in the cases of anodic mono- and multi-tips. In the mono-tip case, the peak corona current is analysed as a function of several experimental parameters such as magnitude, frequency and duration of pulsed voltage and gap distance. The variation of the corona discharge current is correlated with the ozone production. Then in the multi-tip case, the electrical behaviour is analysed as a function of the distance between two contiguous tips and the tip number in order to highlight the region of creation active species for the lowest dissipated power. Intensified charge-coupled device pictures and electric field calculations as a function of inter-tip distance are performed to analyse the mutual effect between two contiguous tips. The optical emission spectra are measured in the UV–visible–NIR wavelength range between 200 nm and 800 nm, in order to identify the main excited species formed in an air corona discharge such as the usual first and second positive systems with first negative systems of molecular nitrogen. The identification of atomic species (O triplet and N) and the quenching of NOγ emission bands are also emphasized.
Bossen, Olaf
We present a new type of calorimeter in which we couple an unknown heat capacity with the aid of Peltier elements to an electrical circuit. The use of an electrical inductance and an amplifier in the circuit allows us to achieve autonomous oscillations, and the measurement of the corresponding resonance frequency makes it possible to accurately measure the heat capacity with an intrinsic statistical error that decreases as ~t^{-3/2} with measuring time t, as opposed to a corresponding error ~t^{-1/2} in the conventional alternating current (a.c.) method to measure heat capacities. We have built a demonstration experiment to show the feasibility of the new technique, and we have tested it on a gadolinium sample at its transition to the ferromagnetic state.
Energetic particle influences in Earth's atmosphere
Aplin, Karen; Harrison, R. Giles; Nicoll, Keri; Rycroft, Michael; Briggs, Aaron
Energetic particles from outer space, known as galactic cosmic rays, constantly ionise the entire atmosphere. During strong solar storms, solar energetic particles can also reach the troposphere and enhance ionisation. Atmospheric ionisation generates cluster ions. These facilitate current flow in the global electric circuit, which arises from charge separation in thunderstorms driven by meteorological processes. Energetic particles, whether solar or galactic in origin, may influence the troposphere and stratosphere through a range of different mechanisms, each probably contributing a small amount. Some of the suggested processes potentially acting over a wide spatial area in the troposphere include enhanced scavenging of charged aerosol particles, modification of droplet or droplet-droplet behavior by charging, and the direct absorption of infra-red radiation by the bending and stretching of hydrogen bonds inside atmospheric cluster-ions. As well as reviewing the proposed mechanisms by which energetic particles modulate atmospheric properties, we will also discuss new instrumentation for measurement of energetic particles in the atmosphere.
升压斩波电路的微分原理及应用分析%Rise to press to cut a differential calculus principle of electric circuit and application analysis
Institute of Scientific and Technical Information of China (English)
Rising to press to cut an electric circuit is an electric power electronics technique application of the foundation be also basic to cut an electric circuit to carry on compound,constitute of premise,its application extensive,is also a theories physics and dynamoelectric physics of concrete application.It of work principle,since match electro-technics of basic request,again have theories physics of characteristic,especially it of application fusion the electric power electronics drag along to move a technique,structure simple,dollar the spare part be little,is an automation control of had better body now.%升压斩波电路是电力电子技术应用的基础,也是基本斩波电路进行复合、构成的前提,其应用范围广泛,更是理论物理和电动物理学的具体应用。它的工作原理,既符合电工技术的基本要求,又具有理论物理的特性,特别是它的应用融合了电力电子拖动技术,结构简单,元器件少,是自动化控制的最好体现。
Demultiplexer circuit for neural stimulation
Wessendorf, Kurt O; Okandan, Murat; Pearson, Sean
A demultiplexer circuit is disclosed which can be used with a conventional neural stimulator to extend the number of electrodes which can be activated. The demultiplexer circuit, which is formed on a semiconductor substrate containing a power supply that provides all the dc electrical power for operation of the circuit, includes digital latches that receive and store addressing information from the neural stimulator one bit at a time. This addressing information is used to program one or more 1:2.sup.N demultiplexers in the demultiplexer circuit which then route neural stimulation signals from the neural stimulator to an electrode array which is connected to the outputs of the 1:2.sup.N demultiplexer. The demultiplexer circuit allows the number of individual electrodes in the electrode array to be increased by a factor of 2.sup.N with N generally being in a range of 2-4.
Phase space representation of neutron monitor count rate and atmospheric electric field in relation to solar activity in cycles 21 and 22
Silva, H. G.; Lopes, I.
Heliospheric modulation of galactic cosmic rays links solar cycle activity with neutron monitor count rate on earth. A less direct relation holds between neutron monitor count rate and atmospheric electric field because different atmospheric processes, including fluctuations in the ionosphere, are involved. Although a full quantitative model is still lacking, this link is supported by solid statistical evidence. Thus, a connection between the solar cycle activity and atmospheric electric field is expected. To gain a deeper insight into these relations, sunspot area (NOAA, USA), neutron monitor count rate (Climax, Colorado, USA), and atmospheric electric field (Lisbon, Portugal) are presented here in a phase space representation. The period considered covers two solar cycles (21, 22) and extends from 1978 to 1990. Two solar maxima were observed in this dataset, one in 1979 and another in 1989, as well as one solar minimum in 1986. Two main observations of the present study were: (1) similar short-term topological features of the phase space representations of the three variables, (2) a long-term phase space radius synchronization between the solar cycle activity, neutron monitor count rate, and potential gradient (confirmed by absolute correlation values above ~0.8). Finally, the methodology proposed here can be used for obtaining the relations between other atmospheric parameters (e.g., solar radiation) and solar cycle activity.
49 CFR 236.723 - Circuit, double wire; line.
... § 236.723 Circuit, double wire; line. An electric circuit not employing a common return wire; a circuit... 49 Transportation 4 2010-10-01 2010-10-01 false Circuit, double wire; line. 236.723 Section 236.723 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL...
49 CFR 236.786 - Principle, closed circuit.
... 49 Transportation 4 2010-10-01 2010-10-01 false Principle, closed circuit. 236.786 Section 236.786 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Principle, closed circuit. The principle of circuit design where a normally energized electric circuit...
A Singularity in the Kirchhoff's Circuit Equations
Harsha, N R Sree
Students often have difficulty in understanding qualitatively the behaviour of simple electric circuits. In particular, as different studies have shown, they find multiple batteries connected in multiple loops difficult to analyse. In a recent paper [Phys. Educ. 50 568 (2015)], we showed such an electric circuit, which consists of ideal batteries connected in parallel, that couldn't be solved by the existing circuit analysis methods. In this paper, we shall introduce a new mathematical method of solving simple electric circuits from the solutions of more general circuits and show that the currents, in this particular circuit, take the indeterminate 0/0 form. We shall also present some of the implications of teaching the method. We believe that the description presented in this paper should help the instructors in teaching the behaviour of multiple batteries connected in parallel.
Nelson, Jane B.
Describes a research-based activity for high school physics students in which they build an LC circuit and find its resonant frequency of oscillation using an oscilloscope. Includes a diagram of the apparatus and an explanation of the procedures. (DDR)
DEFF Research Database (Denmark)
A switch-mode power circuit comprises a controllable element and a control unit. The controllable element is configured to control a current in response to a control signal supplied to the controllable element. The control unit is connected to the controllable element and provides the control...
30 CFR 56.6605 - Isolation of blasting circuits.
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Isolation of blasting circuits. 56.6605 Section... Extraneous Electricity § 56.6605 Isolation of blasting circuits. Lead wires and blasting lines shall be... sources of stray or static electricity. Blasting circuits shall be protected from any contact...
大气电场仪标定系统的设计与仿真%Design and simulation for calibration system of atmospheric electric field instrument
Institute of Scientific and Technical Information of China (English)
黎志波; 李进; 曾杨; 李毅聪
This paper introduces the calibration principle and meaning of atmospheric electric field instrument. The calibration system of atmospheric electric field instrument is given a simulation analysis based on ANSYS software. The effect of distance of each plate, position of the probe and marginal effect of electric field on electrostatic field are discussed respectively, which provide reliable basis for the design of calibration system.%文章介绍了大气电场仪的标定原理及意义,采用ANSYS软件对大气电场仪标定系统进行仿真分析,依次分析了板间距离、探头位置和电场边缘效应对静电场环境的影响,为标定系统的设计提供了可靠的依据。
New energy management circuit applied in electric self-power supply over high voltage side%新型高压侧自供电电源设计与研究
Institute of Scientific and Technical Information of China (English)
李衍川; 江和
分析了高压电场能量收集的原理,建立静电场耦合分布电容模型,并通过实验证明了模型的参考价值。随后,分析使用整流桥电路进行能量管理时的最佳功率点,并从增大超级电容充电电流的角度,设计了一种新型的管理电路,即同步电荷提取电路,以获得最佳的能量存储能力。结果证明存在一个最佳占空比使得收集的能量最大化,从而缩短无线节点在线监测工作周期。%The theory of energy harvested from the high voltage is analyzed, and then the corresponding model of coupling capacitance derived from static electric field is built, and several experiments are conducted to study whether the model is valuable. Then, according to what the result reveals, the optimal power point is found out when energy is managed by rectifier circuit. The value of charged current to super capacitor is used as the judge-ment whether the circuit system has the best storage performance. In that respect, management circuit is improved as a technology called Synchronous Electric Charge Extract, because the rectifier circuit can' t perform as good as it is under ultrahigh voltage. It turns out that there is an optimal duty to maximize the energy harvested, so that the energy harvester can scavenge much more energy to cancellout the power loss. As a result, online monitoring period could be shortened greatly.
A statistical study on precursory effects of earthquakes observed through the atmospheric vertical electric field in northeast India
Directory of Open Access Journals (Sweden)
Abhijit Choudhury
Full Text Available The study of anomalous variations in the near-surface atmospheric vertical electric field (VEF that have the form of bay-like depressions in strength have been used as precursors of earthquakes in various studies. We present here the first statistical report from an earthquake-prone zone in northeast India from July 2009 to July 2012. The 10 days that were meteorologically fair and with earthquake occurrences were selected for the present analysis. The average VEF bay durations and depths were ca. 50 min to 70 min, with the corresponding magnitudes of 500 Vm-1 to 800 Vm-1. Anomalous variation in VEF before 7 to 12 hour of the impending earthquake has been observed. There was a 31% probability that a VEF bay would show as an earthquake precursor. The positive correlation coefficient was 0.72 between the VEF bay depth and the ratio of earthquake magnitude to depth, while the negative correlation coefficient of 0.82 was calculated between VEF bay duration and the ratio of earthquake magnitude to depth. There was moderate correlation for distance of the earthquake epicenter to the observation point with both VEF bay depth and VEF bay duration. The correlation of the time difference of VEF variations and earthquakes with VEF bay depth was good, whereas the correlation of the time difference of VEF variations and earthquakes with VEF bay duration was too low to be considered.
Short-Circuit Withstand Current Rating for Low Voltage Switchgear : Short-Circuit Current Rating (SCCR)
Schütt, Matthias
The subject of this thesis was to observe the short-circuit currents at electrical distribution boards. The purpose was to investigate different methods of protecting switchgears from dam-ages caused by short-circuit currents. Manufactures of switchgears need to indicate the rated short-circuit withstand current of their assembly. This thesis is presenting methods of defining the right value of the short-circuit withstand current. This thesis presents theoretical information about the cau...
TIME DOMAIN REFLECTOMETRY FOR THE LOCALIZATION OF ELECTRICAL FAULTS IN THE INSTRUMENTATION OF THE LHC STRING MAGNETS A Study Case of Voltage Tap, Temperature, and Pressure Transducer Circuits
Komorowski, P
Time Domain Reflectometry (TDR) is one of the most powerful methods used to analyze the integrity of the signal propagating in a transmission line. The method is based on the principle that the wave propagating in the line is reflected at the locations where the impedance of the line changes. The fault points, joints, branches, junctions, abrupt cross-section changes, etc., cause such reflections. The reflectometry technique involves the excitation of the circuit under test with either a fast edge step function or a well-defined impulse confined in time and frequency domains, and thereafter detection of the amplitude and time of the reflections. Both variants of the method were successfully applied to localize open circuit faults in the voltage tap connections, pressure transducers, and temperature sensing carbon gages circuits of the LHC String Dipole Magnet MB2 and Short Straight Section Quadrupole.
Wireless system for location of permanent faults by short circuit current monitoring in electric power distribution network; Sistema wireless para localizacao de faltas permanentes atraves da monitoracao da corrente de curto-circuito em redes de distribuicao de energia eletrica
Energy Technology Data Exchange (ETDEWEB)
Machado, A.G.; Correa, A.C.; Machado, R.N. das M.; Ferreira, A.M.D.; Pinto, J.A.C. [Instituto Federal de Educacao, Ciencia e Tecnologia do Para (IFPA), Belem, PA (Brazil)], E-mail: email@example.com; Barra Junior, W. [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Inst. de Tecnologia. Faculdade de Engenharia Eletrica], E-mail: firstname.lastname@example.com
This paper presents the development of an automatic system for permanent short-circuits location in medium voltage (13.8 kV) electric power system distribution feeders, by indirect monitoring of the line current. When a permanent failure occurs, the developed system uses mobile telephony (GSM) text messages (SMS) to inform the power company operation center where the failure most likely took place. With this information in real time, the power company operation center may provide the network restoration in a faster and efficient way. (author)
Balanced calibration of resonant shunt circuits for piezoelectric vibration control
DEFF Research Database (Denmark)
Høgsberg, Jan; Krenk, Steen
Shunting of piezoelectric transducers and suitable electric circuits constitutes an effective passive approach to resonant vibration damping of structures. Most common design concepts for resonant resistor-inductor (RL) shunt circuits rely on either maximization of the attainable modal damping...
International Nuclear Information System (INIS)
EDA technique is used for circuit simulation. The circuit simulation and the analysis are made for a gate circuit one-shot multivibrator. The result shows: EDA circuit simulation is very useful technique
Institute of Scientific and Technical Information of China (English)
李桓; 杨立军; 李俊岳; 邓黎丽; 张宝红
用计算机控制的高性能数据采集系统对CO2焊短路过渡过程的电参数进行了研究.分析认为可利用电弧电压来指示熔滴短路及电弧复燃,利用电弧电压的微分来指示液体小桥缩颈,为CO2焊短路过渡实时控制奠定了基础.%The electric parameters of the short-circuit transfer of CO2 arc welding are examined totally and systematically by using an advanced data-collecting system controlled by a computer.Stadies and analysis of the above data show that the arc voltage can reflect the droplet short circuit and the arc re-start,and its differential signal can indicate the pinch of the liquid bridge.This is a better foundation for developing the real-time control of short-circuit transfer of CO2 arc welding.
Measurements of the Atmospheric Electric Field through a Triangular Array and the Long-range Saharan Dust Electrification in Southern Portugal
Silva, H. G.; Lopes, F.; S. Pereira; Barbosa, S. M.; Nicoll, K.; Pereira, M. Collares; Harrison, R. G.
Atmospheric electric field (AEF) measurements were carried out in three different sites forming a triangular array in Southern Portugal. The campaign was performed during the summer characterized by Saharan dust outbreaks; the 16th-17th July 2014 desert dust event is considered here. Evidence of long-range dust electrification is attributed to the air-Earth electrical current creating a positive space-charge inside of the dust layer. An increase of ~23 V/m is observed in AEF on the day of the...
Chen, Wai-Kai
Featuring hundreds of illustrations and references, this book provides the information on analog and VLSI circuits. It focuses on analog integrated circuits, presenting the knowledge on monolithic device models, analog circuit cells, high performance analog circuits, RF communication circuits, and PLL circuits.
Electrical machines with Matlab
Gonen, Turan
Basic ConceptsDistribution SystemImpact of Dispersed Storage and GenerationBrief Overview of Basic Electrical MachinesReal and Reactive Powers in Single-Phase AC CircuitsThree-Phase CircuitsThree-Phase SystemsUnbalanced Three-Phase LoadsMeasurement of Average Power in Three-Phase CircuitsPower Factor CorrectionMagnetic CircuitsMagnetic Field of Current-Carrying ConductorsAmpère's Magnetic Circuital LawMagnetic CircuitsMagnetic Circuit with Air GapBrief Review of FerromagnetismMagnetic Core LossesHow to Determine Flux for a Given MMFPermanent MagnetsTransformersTransformer ConstructionBrief Rev
Approaching the Processes in the Generator Circuit Breaker at Disconnection through Sustainability Concepts
Carmen A. Bulucea; Nikos E. Mastorakis; Doru A. Nicola; Marc A. Rosen; Cornelia A. Bulucea
Nowadays, the electric connection circuits of power plants (based on fossil fuels as well as renewable sources) entail generator circuit-breakers (GCBs) at the generator terminals, since the presence of that electric equipment offers many advantages related to the sustainability of a power plant. In an alternating current (a.c.) circuit the interruption of a short circuit is performed by the circuit-breaker at the natural passing through zero of the short-circuit current. During the current i...
Electrical and electronic principles
Knight, S A
Electrical and Electronic Principles, 2, Second Edition covers the syllabus requirements of BTEC Unit U86/329, including the principles of control systems and elements of data transmission. The book first tackles series and parallel circuits, electrical networks, and capacitors and capacitance. Discussions focus on flux density, electric force, permittivity, Kirchhoff's laws, superposition theorem, arrangement of resistors, internal resistance, and powers in a circuit. The text then takes a look at capacitors in circuit, magnetism and magnetization, electromagnetic induction, and alternating v
《电路理论》课程"翻转课堂"的探索%The Exploration on the flipped classroom of electric circuit theory"curriculum
Institute of Scientific and Technical Information of China (English)
田莉; 李延平; 孙静; 张向华
Flipped classroom is a new kind of teaching model. This paper presents the practice of applying this new model onto the curriculum teaching of"electric circuit theory". The teaching structure and the video processing of the flipped classroom on "electric circuit theory" are proposed. These results can provide some guidance on the practice of the flipped classroom and moti-vated the further exploration of the flipped classroom.%"翻转课堂"是一种新的教学模式。本文尝试在电路理论课堂采用"翻转课堂",提出了"翻转课堂"的教学结构以及"翻转课堂"所需的微视频的制备流程,为"翻转课堂"实施提供一定的指导,从而推动翻转课堂的进一步研究。
Graphene radio frequency receiver integrated circuit.
Han, Shu-Jen; Garcia, Alberto Valdes; Oida, Satoshi; Jenkins, Keith A; Haensch, Wilfried
Graphene has attracted much interest as a future channel material in radio frequency electronics because of its superior electrical properties. Fabrication of a graphene integrated circuit without significantly degrading transistor performance has proven to be challenging, posing one of the major bottlenecks to compete with existing technologies. Here we present a fabrication method fully preserving graphene transistor quality, demonstrated with the implementation of a high-performance three-stage graphene integrated circuit. The circuit operates as a radio frequency receiver performing signal amplification, filtering and downconversion mixing. All circuit components are integrated into 0.6 mm(2) area and fabricated on 200 mm silicon wafers, showing the unprecedented graphene circuit complexity and silicon complementary metal-oxide-semiconductor process compatibility. The demonstrated circuit performance allow us to use graphene integrated circuit to perform practical wireless communication functions, receiving and restoring digital text transmitted on a 4.3-GHz carrier signal.
基于大气电场的雷电监测预警技术研究%Lightning Detection and Warning Based on the Atmospheric Electric Field
Institute of Scientific and Technical Information of China (English)
潘家利; 王明亮; 吴海; 张茂华; 徐力泉
通过安装于海口永庄地面观测站内的AMEO340大气电场仪监测到的2011年度大气电场资料.并结合闪电定位、多普勒雷达资料,重点研究小范围区域(监测点中心2km区域)内过顶雷暴天气大气电场特征,寻找雷暴发生时大气电场强度的预警阈值以及预警时间值,为今后针对高尔夫、油库等小范围区域开展雷电预警专项服务打下基础。%Basing on the atmospheric electric field data detected by the AMEO340 instrument over Yongzhuang ground-based observation station of Haikou province in 2011, combined with lightning location data and Doppler radar data, the atmospheric electric field characteristics of over-top thunderstorms in small area (2km around the center of the monitoring points) were analyzed. It indicates the warning threshold and the warning time of atmospheric electric field strength.
The role of cosmic rays in the Earth's atmospheric processes
Indian Academy of Sciences (India)
Devendraa Siingh; R P Singh
In this paper, we have provided an overview of cosmic ray effects on terrestrial processes such as electrical properties, global electric circuit, lightning, cloud formation, cloud coverage, atmospheric temperature, space weather phenomena, climate, etc. It is suggested that cosmic rays control short-term and long-term variations in climate. There are many basic phenomena which need further study and require new and long-term data set. Some of these have been pointed out.
Rocket borne instrument to measure electric fields inside electrified clouds
Ruhnke, L. H. (Inventor)
An apparatus for measuring the electric field in the atmosphere which includes a pair of sensors carried on a rocket for sensing the voltages in the atmosphere being measured is described. One of the sensors is an elongated probe with a fine point which causes a corona current to be produced as it passes through the electric field. An electric circuit is coupled between the probe and the other sensor and includes a high ohm resistor which linearizes the relationship between the corona current and the electric field being measured. A relaxation oscillator and transmitter are provided for generating and transmitting an electric signal having a frequency corresponding to the magnitude of the electric field.
Circuits in the Sun: Solar Panel Physics
Gfroerer, Tim
Typical commercial solar panels consist of approximately 60 individual photovoltaic cells connected in series. Since the usual Kirchhoff rules apply, the current is uniform throughout the circuit, while the electric potential of the individual devices is cumulative. Hence, a solar panel is a good analog of a simple resistive series circuit, except…
Understanding the Behaviour of Infinite Ladder Circuits
Ucak, C.; Yegin, K.
Infinite ladder circuits are often encountered in undergraduate electrical engineering and physics curricula when dealing with series and parallel combination of impedances, as a part of filter design or wave propagation on transmission lines. The input impedance of such infinite ladder circuits is derived by assuming that the input impedance does…
The electrical charging of inactive aerosols in high ionised atmosphere, the electrical charging of artificial beta radioactive aerosols; Le processus de charge electrique: des aerosols non radioactifs en milieu fortement ionise, des aerosols radioactifs artificiels emetteurs beta
Energy Technology Data Exchange (ETDEWEB)
Gensdarmes, F
The electrical properties of aerosols greatly influence their transport and deposition in a containment. In a bipolar ionic atmosphere, a neutral electric charge on aerosols is commonly assumed. However, many studies report a different charge distribution in some situations, like highly ionised atmosphere or in the case of radioactive aerosols. Such situations could arise from a hypothetical accident in a nuclear power plant. Within the framework of safety studies which are carried out at IPSN, our aims were the study of electrical properties of aerosols in highly ionised atmosphere, and the study of artificial radioactive aerosols, in order to suggest experimental validation of available theories. For this purpose, we designed an experimental device that allows us to measure non-radioactive aerosol charge distribution under high gamma irradiation, up to 10{sup 4} Gy/h. With our experimental device we also studied the properties of small ions in the medium. Our results show a variation of the charge distribution in highly ionised atmosphere. The charge increases with the dose of gamma ray. We have related this variation with the one of the small ions in the gases, according to theoretical prediction. However, the model overestimates slightly our experimental results. In the case of the radioactive aerosols, we have designed an original experimental device, which allows us to study the charge distribution of a {sup 137}Cs aerosol. Our results show that the electric charging of such aerosols is strongly dependent on evolution parameters in a containment. So, our results underline a great enhancement of self-charging of particles which are sampled in a confined medium. Our results are qualitatively in agreement with the theoretical model; nevertheless the latter underestimates appreciably the self-charging, owing to the fact that wall effects are not taken into account. (author)
Institute of Scientific and Technical Information of China (English)
曹云东; 王尔智; 刘晓明
运用有限元法FEM对罐式SF6断路器断口附近三维电场进行了数值计算,以计算机辅助绘图为支撑,完成了SF6断路器三维电场的数值模拟。在三维电场数学模型的建立中考虑了屏蔽罩和并联电容器组的存在; 对断路器不同三维剖面的等电位线分布及电场分布情况进行了分析; 并将计算结果进行三维图形可视化处理及显示。%In this paper, three-dimensional electric field of SF6 circuit breaker has been calculated by applying the finite element method based on the computer aided graphic, the 3-D electric field numerical simulations are achieved. In the mathematic models of the three dimensional electric field,the shield and the parallel capacitors are considered; the potential and the electric field distributions of the different three-dimensional profiles are analyzed and figured.
Collective of mechatronics circuit
International Nuclear Information System (INIS)
This book is composed of three parts, which deals with mechatronics system about sensor, circuit and motor. The contents of the first part are photo sensor of collector for output, locating detection circuit with photo interrupts, photo sensor circuit with CdS cell and lamp, interface circuit with logic and LED and temperature sensor circuit. The second part deals with oscillation circuit with crystal, C-R oscillation circuit, F-V converter, timer circuit, stability power circuit, DC amp and DC-DC converter. The last part is comprised of bridge server circuit, deformation bridge server, controlling circuit of DC motor, controlling circuit with IC for PLL and driver circuit of stepping motor and driver circuit of Brushless.
The Effect of Sintering Atmosphere on Electrical Characteristics of Fe2TiO5 Pellet Ceramics Sintered at 1200°C for NTC Thermistor
Wiendartun; Risdiana; Fitrilawati; Siregar, R. E.
Fabrication of Fe2TiO5 pellet ceramics using powder metallurgy technique for NTC thermistor has been carried out, in order to know the effect of sintering atmosphere (Oxygen, Air and Argon Gas) on the characteristic especially the electrical characteristic of Fe2TiO5 ceramics with high working temperature. X-ray diffraction analyses (XRD) was done to know crystal structure and phases formation. A SEM analysis was carried out to know microstructure of pellets. Electrical properties characterization was done through measurement of electrical resistance at various temperatures (room temperature to 250oC). The XRD data showed that the pellets crystallize in orthorhombic. The presence of second phase could not be identified from the XRD analyses. The SEM images showed that the grains size of the ceramic sintered in oxygen gas is smaller than that of the ceramic sintered in air and argon gas. Electrical data showed that the pellet ceramics sintered in oxygen gas had the largest room temperature resistance (RRT), thermistor constant (B), activation energy (Ea) and sensitivity (α) compared to those sintered in air and argon gas. From the electrical characteristics data, it was known that the electrical characteristics of the Fe2TiO5 pellet ceramics followed the NTC characteristic. The value of B and RRT of the produced Fe2TiO5 ceramics namely B = 4389-6149 K and Rrt = 342-26548kQ, fitted market requirement and can be used for temperature sensor.
Uniform and non-uniform modes of nanosecond-pulsed dielectric barrier discharge in atmospheric air: fast imaging and spectroscopic measurements of electric field.
Liu, Chong; Dobrynin, Danil; Fridman, Alexander
In this study, we report experimental results on fast ICCD imaging of development of nanosecond-pulsed dielectric barrier discharge (DBD) in atmospheric air and spectroscopic measurements of electric field in the discharge. Uniformity of the discharge images obtained with nanosecond exposure times were analyzed using chi-square test. The results indicate that DBD uniformity strongly depends on applied (global) electric field in the discharge gap, and is a threshold phenomenon. We show that in the case of strong overvoltage on the discharge gap (provided by fast rise times), there is transition from filamentary to uniform DBD mode which correlates to the corresponding decrease of maximum local electric field in the discharge. PMID:25071294