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Red shift in spectra of galaxies as a consequence of gravitational radiation of the same level as electromagnetic
S. I. Fisenko; I. S. Fisenko
In elaboration of the results presented earlier the red shift is also regarded in this investigation as a widening of electromagnetic radiation spectra, determined by the existence of gravitational radiation of a banded spectrum of the same level as electromagnetic.
The Teaching of Electromagnetism at University Level
ERIC Educational Resources Information Center
Houldin, J. E.
Discusses different kinds of material presentation in the teaching of electromagnetism at the university level, including three "classical" approaches and the Keller personalized proctorial system. Indicates that a general introduction to generators and motors may be useful in an electromagnetism course. (CC)
Russo, Matthew [Department of Physics, University of Toronto, 60 St. George St., Toronto, ON M5S 1A7 (Canada); Thompson, Christopher [Canadian Institute for Theoretical Astrophysics, 60 St. George St., Toronto, ON M5S 3H8 (Canada)
The theory of cold, relativistic, magnetohydrodynamic outflows is generalized by the inclusion of an intense radiation source. In some contexts, such as the breakout of a gamma-ray burst (GRB) jet from a star, the outflow is heated to a high temperature at a large optical depth. Eventually it becomes transparent and is pushed to a higher Lorentz factor by a combination of the Lorentz force and radiation pressure. We obtain its profile, both inside and outside the fast magnetosonic critical point, when the poloidal magnetic field is radial and monopolar. Most of the energy flux is carried by the radiation field and the toroidal magnetic field that is wound up close to the rapidly rotating engine. Although the entrained matter carries little energy, it couples the radiation field to the magnetic field. Then the fast critical point is pulled inward from infinity and, above a critical radiation intensity, the outflow is accelerated mainly by radiation pressure. We identify a distinct observational signature of this hybrid outflow: a hardening of the radiation spectrum above the peak of the seed photon distribution, driven by bulk Compton scattering. The non-thermal spectrum-obtained by a Monte Carlo method-is most extended when the Lorentz force dominates the acceleration, and the seed photon beam is wider than the Lorentz cone of the MHD fluid. This effect is a generic feature of hot, magnetized outflows interacting with slower relativistic material. It may explain why some GRB spectra appear to peak at photon energies above the original Amati et al. scaling. A companion paper addresses the case of jet breakout, where diverging magnetic flux surfaces yield strong MHD acceleration over a wider range of Lorentz factor.
Identification of mineral deposits using airborne electromagnetic spectra
Haoping Huang; I. J. Won
Summary Broadband frequency-domain electromagnetic sensors can be used not only to detect but also to characterize and identify a particular mineral deposit based on its spectral response. The concept is similar to identifying a particular landmine based on its unique spectral response, which is known as Electromagnetic Induction Spectroscopy (EMIS). Recent advances in single -coil, broadband sensors have brought a
Polarized linewidth-controllable double-trapping electromagnetically induced transparency spectra in a resonant plasmon nanocavity
Wang, Luojia; Gu, Ying; Chen, Hongyi; Zhang, Jia-Yu; Cui, Yiping; Gerardot, Brian D.; Gong, Qihuang
Surface plasmons with ultrasmall optical mode volume and strong near field enhancement can be used to realize nanoscale light-matter interaction. Combining surface plasmons with the quantum system provides the possibility of nanoscale realization of important quantum optical phenomena, including the electromagnetically induced transparency (EIT), which has many applications in nonlinear quantum optics and quantum information processing. Here, using a custom-designed resonant plasmon nanocavity, we demonstrate polarized position-dependent linewidth-controllable EIT spectra at the nanoscale. We analytically obtain the double coherent population trapping conditions in a double-? quantum system with crossing damping, which give two transparent points in the EIT spectra. The linewidths of the three peaks are extremely sensitive to the level spacing of the excited states, the Rabi frequencies and detunings of pump fields, and the Purcell factors. In particular the linewidth of the central peak is exceptionally narrow. The hybrid system may have potential applications in ultra-compact plasmon-quantum devices. PMID:24096943
The Teaching of Electromagnetic Induction at Sixth Form Level
ERIC Educational Resources Information Center
Archenhold, W. F.
Presents some ideas about teaching electromagnetic induction at sixth form level, including educational objectives, learning difficulties, syllabus requirements, selection of unit system, and sequence of material presentation. Suggests the Education Group of the Institute of Physics hold further discussions on these aspects before including the…
An Electromagnetic Resonance Circuit for Liquid Level Detection
ERIC Educational Resources Information Center
Hauge, B. L.; Helseth, L. E.
Electromagnetic resonators are often used to detect foreign materials. Here we present a simple experiment for the measurement of liquid level. The resonator, consisting of a coil and a capacitor, is brought to resonance by an external magnetic field source, and the corresponding resonance frequency is determined using Fourier analysis combined…
The NA62 Liquid Krypton Electromagnetic Calorimeter Level 0 Trigger
Bonaiuto, V; Paoluzzi, G; Salamon, A; Salina, G; Santovetti, E; Sargeni, F; Scarfě, F M
The NA62 experiment at CERN SPS aims to measure the Branching Ratio of the very rare kaon decay K+ -> pi+ nu nubar collecting O(100) events with a 10% background to make a stringent test of the Standard Model. One of the main backgrounds to the proposed measurement is represented by the K+ -> pi+ pi0 decay. To suppress this background an efficient photo veto system is foreseen. In the 1-10 mrad angular region the NA48 high performance liquid krypton electromagnetic calorimeter is used. The design, implementation and current status of the Liquid Krypton Electromagnetic Calorimeter Level 0 Trigger are presented.
The NA62 Liquid Krypton Electromagnetic Calorimeter Level 0 Trigger
V. Bonaiuto; A. Fucci; G. Paoluzzi; A. Salamon; G. Salina; E. Santovetti; F. Sargeni; F. M. Scarfi'
The NA62 experiment at CERN SPS aims to measure the Branching Ratio of the very rare kaon decay K+ -> pi+ nu nubar collecting O(100) events with a 10% background to make a stringent test of the Standard Model. One of the main backgrounds to the proposed measurement is represented by the K+ -> pi+ pi0 decay. To suppress this background an efficient photo veto system is foreseen. In the 1-10 mrad angular region the NA48 high performance liquid krypton electromagnetic calorimeter is used. The design, implementation and current status of the Liquid Krypton Electromagnetic Calorimeter Level 0 Trigger are presented.
The NA62 Liquid Krypton Electromagnetic Calorimeter Level 0 Trigger
Vincenzo Bonaiuto; Adolfo Fucci; Giovanni Paoluzzi; Andrea Salamon; Gaetano Salina; Emanuele Santovetti; Fausto Sargeni; Francesco M. Scarfi'
The NA62 experiment at CERN SPS aims to measure the Branching Ratio of the very rare kaon decay K+ -> pi+ nu nubar collecting O(100) events with a 10% background to make a stringent test of the Standard Model. One of the main backgrounds to the proposed measurement is represented by the K+ -> pi+ pi0 decay. To suppress this background an efficient photo veto system is foreseen. In the 1-10 mrad angular region the NA48 high performance liquid krypton electromagnetic calorimeter is used. The design, implementation and current status of the Liquid Krypton Electromagnetic Calorimeter Level 0 Trigger are presented.
Atomistic Modeling of IR Action Spectra Under Circularly Polarized Electromagnetic Fields: Toward Action VCD Spectra.
Calvo, Florent
The nonlinear response and dissociation propensity of an isolated chiral molecule, camphor, to a circularly polarized infrared laser pulse was simulated by molecular dynamics as a function of the excitation wavelength. The results indicate similarities with linear absorption spectra, but also differences that are ascribable to dynamical anharmonic effects. Comparing the responses between left- and right-circularly polarized pulses in terms of dissociation probabilities, or equivalently between R- and S-camphor to a similarly polarized pulse, we find significant differences for the fingerprint C?=?O amide mode, with a sensitivity that could be sufficient to possibly enable vibrational circular dichroism as an action technique for probing molecular chirality and absolute conformations in the gas phase. Chirality 27:253-261, 2015. © 2015 Wiley Periodicals, Inc. PMID:25689775
Jet-cooled naphthalene. II. Single vibronic level fluorescence spectra
NASA Astrophysics Data System (ADS)
Beck, S. M.; Hopkins, J. B.; Powers, D. E.; Smalley, R. E.
Single vibronic level fluorescence spectra have been measured for naphthalene cooled in a supersonic free jet. Ten spectra in all have been recorded, the excitation energies ranging from 0 to 4029 cm-1 above the 1B3u(??*)?1Ag origin. These results reveal extensive intramolecular vibrational redistribution (IVR) occurring in the absence of collision on a time scale much faster than fluorescence even at vibrational energies as low as 2570 cm-1. Comparison of the observed spectra with model calculations shows that this IVR process involves most of the harmonic overtone/combination basis states of overall b1g symmetry having energies within the absorption line profile.
Patterns of energy levels and spectra for polyatomic molecules
Harter, W.G.
Laser spectroscopy has revealed a remarkable intricacy in the rotational, vibrational, and electronic energy levels for polyatomic molecules. The infrared spectra of SF/sub 6/, CF/sub 4/, and related molecules contain several levels of structure on top of structure which resembles a fractal in some ways. The purpose of this article will be to exhibit some of this structure and introduce the simplest theoretical interpretations of it which are presently available.
Estimation of vertical sea level muon energy spectra from the latest primary cosmic ray elemental spectra
NASA Astrophysics Data System (ADS)
Mitra, M.; Molla, N. H.; Bhattacharyya, D. P.
The directly measured elemental spectra of primary cosmic rays obtained from Webber et al., Seo et al., Menn et al., Ryan et al. and experiments like JACEE, CRN, SOKOL, RICH on P, He, CNO, Ne-S and Fe have been considered to estimate the vertical sea level muon energy spectra. The primary elemental energy spectra of P, He, CNO, Ne-S and Fe available from the different experimental data duly fitted by power law are given by Np(E)dE = 1.2216E-2.68 dE [cm2 .s.sr.GeV/n]-1 NHe(E)dE = 0.0424E-2.59 dE [cm2 .s.sr.GeV/n]-1 NCNO(E)dE = 0.0026E-2.57 dE[cm2 .s.sr.GeV/n]-1 NNe-S(E)dE = 0.00066E-2.57 dE [cm2 .s.sr.GeV/n]-1 NF e(E)dE = 0.0056E-2.55 dE [cm2 .s.sr.GeV/n]-1 Using the conventional superposition model the all nucleon primary cosmic ray spectrum has been derived which is of the form N(E)dE = 1.42E-2.66 dE [cm2 .s.sr.GeV/n]-1 We have considered all these spectra separately as parents of the secondary mesons and finallty the sea level muon fluxes at 00 from each species have been derived. To evaluate the meson spectra which are the initial air shower interaction products initiated by the primary nucleon air collisions, the hadronic energy moments have been calculated from the CERN LEBCEHS data for pp collisions and FNAL data for ?p collisions. Pion production by secondary pions have been taken into account and the final total muon spectrum has been derived from pp rightarrow?± x, pp ? K± x, ?p ? ?± x channels. The Z-factors have been corrected for p-air collisions. We have adopted the constant values of ?p-air and ??-air crosssections which are 273 mb and 213 mb, respectively. The adopted inelastic cross-sections for pp and ?p interactions are 35 mb and 22 mb, respectively. The Q-G plasma correction of Z-factors have also been incorporated in the final form. The solution to the standard differential equation for mesons is considered for muon flux estimation from Ngenerations of the parent mesons. By this formulation vertical muon spectra from each element along with the total primary nucleon spectrum have been derived. We wanted to observe the different shape of the muon spectra evaluated from different elemental spectra and to make a comparative study of that. In this energy range (102 - 104 ) GeV we have observed that the majority of the total muon flux is coming from the proton spectra. The contribution from the other elemental spectra to the total muon flux is not at all comparable with that of proton spectra.
GRABGAM Analysis of Ultra-Low-Level HPGe Gamma Spectra
Winn, W.G.
The GRABGAM code has been used successfully for ultra-low level HPGe gamma spectrometry analysis since its development in 1985 at Savannah River Technology Center (SRTC). Although numerous gamma analysis codes existed at that time, reviews of institutional and commercial codes indicated that none addressed all features that were desired by SRTC. Furthermore, it was recognized that development of an in-house code would better facilitate future evolution of the code to address SRTC needs based on experience with low-level spectra. GRABGAM derives its name from Gamma Ray Analysis BASIC Generated At MCA/PC.
Identifying New Fe I Levels from Stellar Spectra
NASA Astrophysics Data System (ADS)
Peterson, Ruth; Kurucz, Robert L.
The spectrum of the Fe I atom is critical to many areas of astrophysics and beyond. Measurements of the energies of its high-lying levels remain woefully incomplete, however, despite extensive laboratory and solar analysis. Here we discuss work by Peterson & Kurucz (2014, ApJS, in press) to identify such levels using high-resolution archival absorption-line ultraviolet and optical spectra of stars, whose warm temperatures favor moderate Fe I excitation. To date this analysis has provided the upper energies of 66 Fe I levels. Many are of higher excitation than is accessible to laboratory experiments; several exceed the Fe I ionization energy. These levels provide new identifications for over two thousand potentially detectable lines. We describe and illustrate our method, which is based on matching the strengths and positions of unidentified spectral features to the lines sharing a particular upper level in Kurucz's semi-empirical calculations. We also highlight the improvements these new identifications bring to the determination of the abundances of trace elements in individual stars, and to the ability of calculations of cool stellar spectra to match low-resolution observations of stars and old stellar systems.
Shape reconstruction in 3D electromagnetic induction tomography using a level set technique
Ascher, Uri M.
Shape reconstruction in 3D electromagnetic induction tomography using a level set technique O. Dorn, Canada Abstract We present a novel shape reconstruction technique for 3D low frequency electromagnetic induction tomography which uses a level set representation of the shapes. An efficient ad- joint scheme
NSDL National Science Digital Library
This is an activity about the properties of electromagnets, which is a crucial underpinning for understanding how magnetic fields are generated in nature, in the surface of the Sun, and in the interior of Earth. Learners will create an electromagnet by letting an electric current flow through a wire to generate a magnetic field, which is then detected using a compass. This activity requires a thin insulated wire, pencil, battery, compass and paper clips. This is Activity 2 of the Magnetism and Electromagnetism teachers guide.
NSDL National Science Digital Library
Michael Horton
In this investigation, students will construct electromagnets and test to see which variables make them stronger. Although elementary and middle school teachers are expected to have done this activity with their classes, teachers of younger students often
Relationships Between Complex Core Level Spectra and Materials Properties
Nelin, Constance J.; Bagus, Paul S.; Ilton, Eugene S.; Chambers, Scott A.; Kuhlenbeck, Helmut; Freund, Hans-Joachim
The XPS of many oxides are quite complex and there may be several peaks of significant intensity for each subshell. These peaks arise from many-electron effects, which normally are treated with configuration interaction (CI) wavefunctions where static correlation effects are taken into account. It is common to use semiempirical methods to determine the matrix elements of the CI Hamiltonian and there are few rigorous CI calculations where parameters are not adjusted to fit experiment. In contrast, we present, in the present work, theoretical XPS spectra obtained with rigorous CI wavefunctions for CeO2 where the XPS are especially complex; several different core levels are studied. This study uses an embedded CeO8 cluster model to represent bulk CeO2 and the relativistic CI wavefunctions are determined using four-component spinors from Dirac-Fock calculations. In particular, we examine the importance of interatomic many-body effects where there is a transfer of electrons from occupied oxygen 2p orbitals into empty cation orbitals as it is common to ascribe the complex XPS to this effect. We also contrast the importance of many-body charge-transfer effects for the isoelectronic cations of Ce4+ and La3+. The long-range goal of this work is to relate the XPS features to the nature of the chemical bonding in CeO2 and we describe our progress toward this goal.
Resonant Spectra of Malignant Breast Cancer Tumors Using the Three-Dimensional Electromagnetic Fast Multipole Model. Part 1
NASA Technical Reports Server (NTRS)
El-Shenawee, Magda
An intensive numerical study for the resonance scattering of malignant breast cancer tumors is presented. The rigorous three-dimensional electromagnetic model, based on the equivalence theorem, is used to obtain the induced electric and magnetic currents on the breast and tumor surfaces. The results show that a non-spherical malignant tumor can be characterized based its spectra regardless of its orientation, the incident polarization, or the incident or scattered directions. The tumor's spectra depend solely on its physical characteristics (i.e., the shape and the electrical properties), however, their locations are not functions of its burial depth. This work provides a useful guidance to select the appropriate frequency range for the tumor's size.
NSDL National Science Digital Library
VU Bioengineering RET Program,
In this activity, the students will complete the grand challenge and design an electromagnet to separate steel from aluminum for the recycler. In order to do this, students compare the induced magnetic field of an electric current with the magnetic field of a permanent magnet and must make the former look like the latter. They discover that looping the current produces the desired effect and find ways to further strengthen the magnetic field.
Spectra of Stimulated Electromagnetic Emission of the Ionosphere Upon Sweeping of the Pump Wave Frequency Near Gyroharmonics. I. Experimental Results
NASA Astrophysics Data System (ADS)
Kotov, P. V.; Sergeev, E. N.; Grach, S. M.
We present the results of experimental studies of the spectra of the stimulated electromagnetic emission excited in the ionosphere by powerful radio waves during the pump wave frequency sweeping near the forth ( n = 4) and fifth ( n = 5) harmonics of the electron cyclotron frequency nf ce. The frequency sweep was carried out for long (continuous) pumping in vertical and inclined directions (at 14° and 18° south of the zenith), as well as for the pulse diagnostic wave both with and without additional pumping far from the gyroharmonics. The dependences of the spectral features of the stimulated electromagnetic emission on the ratio between the pump-wave frequency f 0 (or on the diagnostic-wave frequency fDW) and nf ce were analyzed. It is found that near the multiple gyroresonance, different spectral features of the stimulated emission are quenched at the same frequency for different pump-wave frequencies. For a sufficiently large inclination of the pump wave beam from the vertical direction, the intensity of the stimulated electromagnetic emission is notably decreased for f 0 ? nf ce as compared with f 0 > nf ce.
NSDL National Science Digital Library
The Exploratorium
Learners construct a spectroscope out of a shoe box or mailing tube, diffraction grating, and other simple materials. They then use their spectroscope to observe spectra, the colors that make up light. Learners compare the spectra of various light sources. Use this activity to introduce learners to basic principles of light and color. Also, look at a related page about auroras to understand how distinguishing spectra of different atoms helps scientists understand the universe.
Lightning electromagnetic radiation field spectra in the interval from 0. 2 to 20 MHz
Willett, J.C. (Air Force Geophysics Lab., Hanscom AFB, MA (USA)); Bailey, J.C. (Univ. of Alabama, Huntsville (USA)); Leteinturier, C. (Inst. de Physique et Chimie des Materiaux (France)); Krider, E.P. (Univ. of Arizona, Tucson (USA))
Average energy spectral densities are presented for the fast transitions in most of the components that produce large radiation field impulses from cloud-to-ground lightning; first and subsequent return strokes; stepped, dart-stepped, and 'chaotic' leaders; and 'characteristic' cloud pulses. A disagreement in the previous literature about the spectral energy radiated by return strokes at high frequencies is noted and explained. The authors show that the spectral amplitudes are not seriously distorted by propagation over less than 35 km of seawater, although as much as 45 km of such propagation does appear to produce significant attenuation above about 10 MHz. First and subsequent return strokes produce identical spectra between 0.2 and 20 MHz. The spectra of stepped and dart-stepped leader steps are nearly identical and are very similar to that of characteristic pulses. The spectra of leader steps also match return stroke spectra above 2-3 MHz after the former are increased by about 7 dB. The shapes of individual spectra do not depend on their amplitude, so the shapes of the average spectra are probably not distorted by the trigger thresholds used in the data acquisition. Return strokes are the strongest sources of radiation from cloud-to-ground lightning in the 0.2- to 20-MHz frequency range, although certain intracloud processes are stronger radiators above 8 MHz.
Surface-enhanced Raman scattering spectra of adsorbates on Cu2O nanospheres: charge-transfer and electromagnetic enhancement
NASA Astrophysics Data System (ADS)
Jiang, Li; You, Tingting; Yin, Penggang; Shang, Yang; Zhang, Dongfeng; Guo, Lin; Yang, Shihe
Surface-enhanced Raman scattering (SERS) spectra of 4-mercaptobenzoic acid (4-MBA) have been investigated on the surface of Cu2O nanospheres. The SERS signals were believed to originate from the static chemical enhancement, resonant chemical enhancement and electromagnetic enhancement. The coupling between the adsorbates and the semiconductor, evidenced by the shift in absorption spectrum of modified Cu2O and the enhancement of non-totally symmetric modes of the 4-MBA and 4-mercaptopyridine (4-MPY) molecules, were invoked to explain the experimental results. Furthermore, simulations were employed to investigate the nature of the enhancement mechanisms operative between the molecules and the semiconductor. Density functional theory (DFT) calculations suggested a charge transfer (CT) transition process between the molecules and the Cu2O nanospheres. Three-dimensional finite-difference time domain (3D-FDTD) simulations were conducted to map out the electromagnetic field around the Cu2O nanospheres. The experimental and simulation results have revealed the promise of the Cu2O nanospheres as a good SERS substrate and the prospect of using the SERS substrate as a valuable tool for in situ investigation and assay of the adsorption behavior on semiconductor surfaces.Surface-enhanced Raman scattering (SERS) spectra of 4-mercaptobenzoic acid (4-MBA) have been investigated on the surface of Cu2O nanospheres. The SERS signals were believed to originate from the static chemical enhancement, resonant chemical enhancement and electromagnetic enhancement. The coupling between the adsorbates and the semiconductor, evidenced by the shift in absorption spectrum of modified Cu2O and the enhancement of non-totally symmetric modes of the 4-MBA and 4-mercaptopyridine (4-MPY) molecules, were invoked to explain the experimental results. Furthermore, simulations were employed to investigate the nature of the enhancement mechanisms operative between the molecules and the semiconductor. Density functional theory (DFT) calculations suggested a charge transfer (CT) transition process between the molecules and the Cu2O nanospheres. Three-dimensional finite-difference time domain (3D-FDTD) simulations were conducted to map out the electromagnetic field around the Cu2O nanospheres. The experimental and simulation results have revealed the promise of the Cu2O nanospheres as a good SERS substrate and the prospect of using the SERS substrate as a valuable tool for in situ investigation and assay of the adsorption behavior on semiconductor surfaces. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr33502j
Halgamuge, Malka N.
PINEAL MELATONIN LEVEL DISRUPTION IN HUMANS DUE TO ELECTROMAGNETIC FIELDS AND ICNIRP LIMITS Malka N to power-frequency (50 or 60 Hz) EMFs is unavoidable. Melatonin is a natural hormone produced by pineal, as a consequence, may decrease the melatonin production. In this study, more than one hundred experimental data
Electromagnetically Induced Transparency using six level atoms doped in the crystalline medium
Hassan Kaatuzian; Sina Mehrabadi; Ahmad Ajdarzadeh Oskouei
Using the density matrix theory of interaction between light and matter, and relevant parameters of the relaxation rates for a six-level model, we have shown theoretically the possibility of realizing Electromagnetically Induced Transparency (EIT) and Slow Light effects in Pr(+3 ion) doped YSO crystal. In addition, we have presented a simplified method to analyse EIT effect in such a six level atomic system. Finally, we have demonstrated results of numerical calculation and have compared them with experimental measurements reported recently.
The Two-Level Model on Absorption Spectra of Oxyhemo- and Neuroglobin
NASA Astrophysics Data System (ADS)
Thi Thao, To; Bernad, Sophie; Derrien, Valerie; Thuy Anh, Chu; Lan, Nguyen Tri; Viet, Nguyen Ai
The absorption spectra of deoxyhemoglobin and oxyneuroglobin has been examined. The well-known two-level model has been used to study the absorption spectra. The model has been verified by experemental data for heomoglobin and neuroglobin, that gives good fittings. The discussion on the obtained results leads to further works
Survey of ambient electromagnetic and radio-frequency interference levels in nuclear power plants
Kercel, S.W.; Moore, M.R.; Blakeman, E.D.; Ewing, P.D.; Wood, R.T.
This document reports the results of a survey of ambient electromagnetic conditions in representative nuclear power plants. The U.S. Nuclear Regulatory Commission (NRC) Office of Nuclear Regulatory Research engaged the Oak Ridge National Laboratory (ORNL) to perform these measurements to characterize the electromagnetic interference (EMI) and radio-frequency interference (RFI) levels that can be expected in nuclear power plant environments. This survey is the first of its kind, being based on long-term unattended observations. The data presented in this report were measured at eight different nuclear units and required 14 months to collect. A representative sampling of power plant conditions (reactor type, operating mode, site location) monitored over extended observation periods (up to 5 weeks) were selected to more completely determine the characteristic electromagnetic environment for nuclear power plants. Radiated electric fields were measured over the frequency range of 5 MHz to 8 GHz. Radiated magnetic fields and conducted EMI events were measured over the frequency range of 305 Hz to 5 MHz. Highest strength observations of the electromagnetic ambient environment across all measurement conditions at each site provide frequency-dependent profiles for EMI/RFI levels in nuclear power plants.
March 17 - 19, 2004: Low-level processing of proteomics spectra, Kevin Coombes
Low-level processing of proteomics spectra Kevin Coombes Department of Biostatistics and Applied Mathematics UT M.D.Anderson Cancer Center Overview z Background and motivation z Description of data set for methodology development and testing z Wavelet
The report gives guidelines for interpreting the low resolution mass spectra (LRMS) of complex chemical mixtures, within the context of the EPA Level 1 Environmental Assessment Program. It discusses the principles underlying direct mass spectrometric analysis of complex mixtures,...
Four-wave mixing in a three-level bichromatic electromagnetically induced transparency system
Yang, G. Q.; Xu, P. [State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan 430071 (China); Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071 (China); Graduate University, Chinese Academy of Sciences, Beijing 100049 (China); Wang, J.; Zhan, M. S. [State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan 430071 (China); Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071 (China); Zhu Yifu [Department of Physics, Florida International University, Miami, Florida 33199 (United States)
We investigate the four-wave mixing (FWM) phenomenon in a three-level bichromatic electromagnetically induced transparency system. Theoretical results predict that the FWM will exhibit a multipeak structure under bichromatic coupling fields. The stronger the coupling fields are, the more FWM the peaks should exhibit. Results of an experiment carried out with cold {sup 87}Rb atoms in a magneto-optical trap agree with the theoretical prediction.
Emulating the Level1 electromagnetic Trigger response using an Offline database. Procedure for populating this database from the Online information
Emilia Becheva; Francesca Cavallari; Pascal Paganini; Louis James Antonelli; Sean Patrick Lynch; Pasquale Musella
The Level-1 Trigger plays a major role in the CMS experiment allowing the reduction of the raw event rate at the Large Hadron Collider. Its decision is based on information from the electromagnetic and hadronic calorimeters as well as the muon detectors. The electronics of the electromagnetic calorimeter generate and deliver basic quantities called "Trigger Primitives" which correspond to local
Evolution of the unidirectional electromagnetic pulses in an anisotropic two-level medium.
Zabolotskii, A A
We find a general integrable system of reduced Maxwell-Bloch equations describing the interaction of a two-component electromagnetic field with the dipole transition of a two-level medium. The anisotropy of the anisotropic dipole momentum of the transition as a permanent dipole momentum is taken into account. A solution of the model is found for a particular case by using the inverse scattering transform. The method is based on a solution of the Riemann-Hilbert problem taking into account the symmetry properties of the corresponding fundamental solutions. PMID:18517539
Electromagnetically induced self-imaging in four-level atomic system.
Wang, Feng; Wang, Chunfang; Cheng, Jing; Zhang, Dawei
In this paper, a special gradient-index electromagnetically induced transparency medium is induced with a Gaussian control field, which can be realized in a four-level ??Rb cold atomic cloud. Special directional self-imaging and imaging transforming properties are studied in this work. Simulated results show that a complex object can be imaged in the cold atoms, as the control field substituted with the elliptical Gaussian beam, then the self-imaging is directional, which has potental application in encryption. PMID:24663467
Evolution of the unidirectional electromagnetic pulses in an anisotropic two-level medium
NASA Astrophysics Data System (ADS)
Zabolotskii, A. A.
We find a general integrable system of reduced Maxwell-Bloch equations describing the interaction of a two-component electromagnetic field with the dipole transition of a two-level medium. The anisotropy of the anisotropic dipole momentum of the transition as a permanent dipole momentum is taken into account. A solution of the model is found for a particular case by using the inverse scattering transform. The method is based on a solution of the Riemann-Hilbert problem taking into account the symmetry properties of the corresponding fundamental solutions.
Electromagnetically induced grating in a four-level tripod-type atomic system
NASA Astrophysics Data System (ADS)
Dong, Ya-Bin; Guo, Yao-Hua
An electromagnetically induced grating in a four-level tripod-type atomic system is studied theoretically. By virtue of a weak standing-wave signal field, the phase modulation effectively diffracts a weak probe field into the first-order direction. By changing the weak signal field, the diffraction of the weak probe field can be modulated in real time, and a first-order diffraction efficiency of more than 32% can be obtained with proper parameters. Such a system has a potential application in an all-optical switch controlled by a weak optical signal.
Improved Experimental and Theoretical Energy Levels of Carbon I from Solar Infrared Spectra
NASA Technical Reports Server (NTRS)
Chang, Edward S.; Geller, Murray
We have improved the energy levels in neutral carbon using high resolution infrared solar spectra. The main source is the ATMOS spectrum measured by the Fourier transaform spectroscopy technique from 600 to 4800 cm-1, supplemented by the MARK IV balloon data, covering from 4700 to 5700 cm-1.
Improved Experimental and Theoretical Energy Levels of Carbon I from Solar Infrared Spectra
Edward S. Chang
We have improved the energy levels in neutral carbon using high resolution infrared solar spectra. The main source is the A TMOS spedtrum measured by the Fourier transform spectroscopy technique from 600 to 4800 cm-l , supplemented by the MARK W balloon data, covering from 4700 to 5700 cm-l . From these infrared data, we have determined 19 new energy
Improved Experimental Energy Levels of Carbon I from Solar Infrared Spectra
Edward S. Chang; Murray Geller
We have improved the energy levels in neutral carbon using high resolution infrared solar spectra. The main source is the space-based ATMOS spectrum measured by the Fourier transform spectroscopy technique from 600 to 4800cm-1. From these infrared data, we have determined 19 new energy levels in the 5f, 5g, 6g and 6h configurations. To extend measurements to higher frequencies, we
New Fe I Level Energies and Line Identifications from Stellar Spectra
NASA Astrophysics Data System (ADS)
Peterson, Ruth C.; Kurucz, Robert L.
The spectrum of the Fe I atom is critical to many areas of astrophysics and beyond. Measurements of the energies of its high-lying levels remain woefully incomplete, however, despite extensive laboratory and solar analysis. In this work, we use high-resolution archival absorption-line ultraviolet and optical spectra of stars whose warm temperatures favor moderate Fe I excitation. We derive the energy for a particular upper level in Kurucz's semiempirical calculations by adopting a trial value that yields the same wavelength for a given line predicted to be about as strong as that of a strong unidentified spectral line observed in the stellar spectra, then checking the new wavelengths of other strong predicted transitions that share the same upper level for coincidence with other strong observed unidentified lines. To date, this analysis has provided the upper energies of 66 Fe I levels. Many new energy levels are higher than those accessible to laboratory experiments; several exceed the Fe I ionization energy. These levels provide new identifications for over 2000 potentially detectable lines. Almost all of the new levels of odd parity include UV lines that were detected but unclassified in laboratory Fe I absorption spectra, providing an external check on the energy values. We motivate and present the procedure, provide the resulting new energy levels and their uncertainties, list all the potentially detectable UV and optical new Fe I line identifications and their gf values, point out new lines of astrophysical interest, and discuss the prospects for additional Fe I energy level determinations.
Phase Control of Electromagnetically Induced Grating in a Doppler-Broadened ?-Type Three-Level System
NASA Astrophysics Data System (ADS)
Qiu, Tian-Hui; Ma, Hong-Yang; Zheng, Chun-Hong; Chen, Li-Bo; Cheng, Qiang
We theoretically investigate the phenomena of electromagnetically induced grating in a doppler-broadened ?-type three-level atomic system with the spontaneously generated coherence (SGC) effect enhanced by an incoherence pump. It is found that the model can effectively diffract a weak probe field into high-order direction. We attribute the enhancement of diffraction mainly to the quantum interference resulting from the cross coupling between the two decay pathways. The diffraction efficiency behaves phase and doppler broadening-dependent phenomena, and can be greatly modulated by the SGC effect. Compared to the counter-propagating case, the co-propagating setting is more suitable for the purpose considered in this paper due to the effectiveness of Doppler-free.
Spectra and energy levels of sodiumlike ions from Y sup 28+ to Sn sup 39+
J. Reader; J. O. Ekberg; U. Feldman; C. M. Brown; J. F. Seely
Spectra of ten sodiumlike ions from Y{sup 28+} to Sn{sup 39+} were observed with laser-produced plasmas and grazing- incidence spectrographs. Wavelengths, energy levels, and ionization energies were determined for all ions of the isoelectronic sequence from Y to Sn. Revised ab initio and fitted values are given for the 3d--4f wavelengths of the sodiumlike ions K{sup 8+} and Rh{sup 34+}.
Effects of electromagnetic fields on photophasic circulating melatonin levels in American kestrels.
Fernie, K J; Bird, D M; Petitclerc, D
Birds reproduce within electromagnetic fields (EMFs) from transmission lines. Melatonin influences physiologic and behavioral processes that are critical to survival, and melatonin has been equivocally suppressed by EMFs in mammalian species. We examined whether EMFs affect photophasic plasma melatonin in reproducing adult and fledgling American kestrels (Falco sparverius), and whether melatonin was correlated with body mass to explain previously reported results. Captive kestrel pairs were bred under control or EMF conditions for one (short-term) or two (long-term) breeding seasons. EMF exposure had an overall effect on plasma melatonin in male kestrels, with plasma levels suppressed at 42 days and elevated at 70 days of EMF exposure. The similarity in melatonin levels between EMF males at 42 days and controls at 70 days suggests a seasonal phase-shift of the melatonin profile caused by EMF exposure. Melatonin was also suppressed in long-term fledglings, but not in short-term fledglings or adult females. Melatonin levels in adult males were higher than in adult females, possibly explaining the sexually dimorphic response to EMFs. Melatonin and body mass were not associated in American kestrels. It is likely that the results are relevant to wild raptors nesting within EMFs. PMID:10544158
Dynamic effects of electromagnetic wave on a damped two-level atom
Z. Y. Zeng; G. J. Zeng; L. M. Kuang; L. D. Zhang
We studied the dynamic effects of an electromagnetic(EM) wave with circular polarization on a two-level damped atom. The results demonstrate interesting ac Stark split of energy levels of damped atom. The split levels have different energies and lifetimes, both of which depend on the interaction and the damping rate of atom. When the frequency of the EM wave is tuned to satisfy the resonance condition in the strong coupling limit, the transition probability exhibits Rabi oscillation. Momentum transfer between atom and EM wave shows similar properties as the transition probability under resonance condition. For a damped atom interacting with EM field, there exists no longer stable state. More importantly, if the angular frequency of the EM wave is tuned the same as the atomic transition frequency and its amplitude is adjusted appropriately according to the damping coefficients, we can prepare a particular 'Dressed State' of the coupled system between atom and EM field and can keep the system coherently in this 'Dressed state' for a very long time. This opens another way to prepare coherent atomic states.
Energy spectra and electromagnetic transition rates of {sup 160,162,164}Gd in the projected Hartree-Fock model
Ghorui, S. K.; Raina, P. K. [Dept. of Physics, IIT Ropar, Rupnagar 140001 (India); Praharaj, C. R.; Patra, S. K. [Institute of Physics, Bhubaneswar 751005 (India); Naik, Z. [Dept. of Physics, Sambalpur University, Burla 768019 (India)
Band structure and electromagnetic properties of bands of {sup 160,162,164}Gd are studied theoretically upto high spin values using self-consisstent mean field theory. Predictions for the band structures are made. A K = 6{sup ?} isomer at fairly low energy is predicted. Four quasi-particle bands involving i{sub 13/2} neutron and h{sub 11/2} protons are also studied.
The cyclopropene radical cation: Rovibrational level structure at low energies from high-resolution photoelectron spectra
NASA Astrophysics Data System (ADS)
Vasilatou, K.; Michaud, J. M.; Baykusheva, D.; Grassi, G.; Merkt, F.
The cyclopropene radical cation (c-C3H_4^+) is an important but poorly characterized three-membered-ring hydrocarbon. We report on a measurement of the high-resolution photoelectron and photoionization spectra of cyclopropene and several deuterated isotopomers, from which we have determined the rovibrational energy level structure of the widetildeX^+ 2B2 ground electronic state of c-C3H_4^+ at low energies for the first time. The synthesis of the partially deuterated isotopomers always resulted in mixtures of several isotopomers, differing in their number of D atoms and in the location of these atoms, so that the photoelectron spectra of deuterated samples are superpositions of the spectra of several isotopomers. The rotationally resolved spectra indicate a C2v-symmetric R0 structure for the ground electronic state of c-C3H_4^+. Two vibrational modes of c-C3H_4^+ are found to have vibrational wave numbers below 300 cm-1, which is surprising for such a small cyclic hydrocarbon. The analysis of the isotopic shifts of the vibrational levels enabled the assignment of the lowest-frequency mode (fundamental wave number of ?110 cm-1 in c-C3H_4^+) to the CH2 torsional mode (? _8^+, A2 symmetry) and of the second-lowest-frequency mode (?210 cm-1 in c-C3H_4^+) to a mode combining a CH out-of-plane with a CH2 rocking motion (? _{15}^+, B2 symmetry). The potential energy along the CH2 torsional coordinate is flat near the equilibrium structure and leads to a pronounced anharmonicity.
Status of the Level 0 Trigger Processor of the NA62 Liquid Krypton Electromagnetic Calorimeter
NASA Astrophysics Data System (ADS)
Bonaiuto, V.; de Simone, N.; Federici, L.; Sargeni, F.; Badoni, D.; Fucci, A.; Paoluzzi, G.; Salamon, A.; Salina, G.; Santovetti, E.; Checcucci, B.; Papi, A.; Piccini, M.; Bizzarri, M.; Venditti, S.
The NA62 experiment at the CERN SPS aims to measure the Branching Ratio of the ultra-rare decay K^+ rightarrow ?^+?bar?, collecting about 100 events in two years of data taking with a signal to background ratio of 10:1. A hermetic photon veto system has been designed to efficiently reject the ?0 background, one of the main background sources, and the 20-ton liquid krypton calorimeter is a fundamental component of such system in the angular acceptance region 1-10 mrad. In this paper, we present the design of the Level 0 trigger processor that is able to identify electromagnetic clusters in the calorimeter providing information on time, position and energy reconstruction for each cluster. In particular, it is composed of 36 readout boards (TEL62), organized in a three layer parallel system, 108 mezzanines and 215 high-performance FPGAs. The system has been designed to sustain an instantaneous hit rate of 40 MHz, to process data with a latency of about 100 ?s, and to achieve a time resolution of 1.5 ns on the single cluster. Performance and functionality test results of a trigger slice, together with an updated status report of the whole level 0 trigger project, will be presented.
Explaining Electromagnetic Plane Waves in a Vacuum at the Introductory Level
ERIC Educational Resources Information Center
Allred, Clark L.; Della-Rose, Devin J.; Flusche, Brian M.; Kiziah, Rex R.; Lee, David J.
A typical introduction to electromagnetic waves in vacuum is illustrated by the following quote from an introductory physics text: "Maxwell's equations predict that an electromagnetic wave consists of oscillating electric and magnetic fields. The changing fields induce each other, which maintains the propagation of the wave; a changing electric…
Magnetic breakdown and Landau level spectra of a tunable double-quantum-well Fermi surface
Simmons, J.A.; Harff, N.E.; Lyo, S.K.; Klem, J.F. [Sandia National Labs., Albuquerque, NM (United States); Boebinger, G.S.; Pfeiffer, L.N.; West, K.W. [Lucent Technologies, Murray Hill, NJ (United States). Bell Labs.
By measuring longitudinal resistance, the authors map the Landau level spectra of double quantum wells as a function of both parallel (B{sub {parallel}}) and perpendicular (B{sub {perpendicular}}) magnetic fields. In this continuously tunable highly non-parabolic system, the cyclotron masses of the two Fermi surface orbits change in opposite directions with B{sub {parallel}}. This causes the two corresponding ladders of Landau levels formed at finite B{sub {perpendicular}} to exhibit multiple crossings. They also observe a third set of landau levels, independent of B{sub {parallel}}, which arise from magnetic breakdown of the Fermi surface. Both semiclassical and full quantum mechanical calculations show good agreement with the data.
Nuclear-level densities around Z = 50 from neutron evaporation spectra in (p, n) reactions
Zhuravlev, B. V.; Lychagin, A. A.; Titarenko, N. N. [Institute for Physics and Power Engineering (Russian Federation)
Neutron excitation functions, spectra, and angular distributions in the (p, n) reactions on the isotopes {sup 116}Sn, {sup 118}Sn, {sup 122}Sn, and {sup 124}Sn were measured in the proton-energy range 7-11 MeV. The measurements were performed by the time-of-flight method with the aid of a fast-neutron spectrometer at the EGP-15 pulsed tandem accelerator of the Institute of Physics and Power Engineering (Obninsk). A high resolution (about 0.6 ns/m) and a high stability of the time-of-flight spectrometer made it possible to identify reliably low-lying levels along with the continuous section of the neutron spectra. The data obtained in this way were analyzed on the basis of the statistical equilibrium and preequilibrium models of nuclear reactions. The respective calculations were performed with the aid of the precise Hauser-Feshbach formalism of statistical theory. The nuclear-level densities in the isotopes {sup 116}Sb, {sup 118}Sb, {sup 122}Sb, and {sup 124}Sb were determined, along with their energy dependences and model parameters. In the excitation-energy range 0-2 MeV, the energy dependence of the nuclear-level densities exhibits a structure that is associated with the shell inhomogeneities of the spectrum of single-particle states near filled shells. The isotopic dependence of the nuclear-level density is discovered and explained. It is also shown that the data obtained here for the nuclear-level density differ markedly from the predictions of model systematics of nuclear-level densities.
Effects of vibrational motion on core-level spectra of prototype organic molecules
Uejio, Janel S.; Schwartz, Craig P.; Saykally, Richard J.; Prendergast, David
A computational approach is presented for prediction and interpretation of core-level spectra of complex molecules. Applications are presented for several isolated organic molecules, sampling a range of chemical bonding and structural motifs. Comparison with gas phase measurements indicate that spectral lineshapes are accurately reproduced both above and below the ionization potential, without resort to ad hoc broadening. Agreement with experiment is significantly improved upon inclusion of vibrations via molecular dynamics sampling. We isolate and characterize spectral features due to particular electronic transitions enabled by vibrations, noting that even zero-point motion is sufficient in some cases.
Electromagnetic Signals from Bacterial DNA
A. Widom; J. Swain; Y. N. Srivastava; S. Sivasubramanian
Chemical reactions can be induced at a distance due to the propagation of electromagnetic signals during intermediate chemical stages. Although is is well known at optical frequencies, e.g. photosynthetic reactions, electromagnetic signals hold true for muck lower frequencies. In E. coli bacteria such electromagnetic signals can be generated by electric transitions between energy levels describing electrons moving around DNA loops. The electromagnetic signals between different bacteria within a community is a "wireless" version of intercellular communication found in bacterial communities connected by "nanowires". The wireless broadcasts can in principle be of both the AM and FM variety due to the magnetic flux periodicity in electron energy spectra in bacterial DNA orbital motions.
Application of Manning's Formula for Estimation of Liquid Metal Levels in Electromagnetic Flow Measurements
NASA Astrophysics Data System (ADS)
Stelian, Carmen
Lorentz force velocimetry is a new technique in electromagnetic flow measurements based on exposing an electrical conducting metal to a static magnetic field and measuring the force acting on the magnet system. The calibration procedure of a Lorentz force flowmeter used in industrial open-channel flow measurements is difficult because of the fluctuating liquid level in the channel. In this paper, the application of Manning's formula to estimate the depth of a liquid metal flowing in an open channel is analyzed by using the numerical modeling. Estimations of Manning's n parameter for aluminum show higher values as compared with water flowing in artificial channels. Saint-Venant equations are solved in order to analyze the wave propagation at the free surface of the liquid. Numerical results show a significant damping of waves at the surface of liquid metals as compared with water. Therefore, the Manning formula can be used to correlate the liquid depth and the flow rate in LFF numerical calibration procedure. These results show that the classical formulas, used exclusively to study the water flow in open channels, can be also applied for the liquid metals. The application of Manning's formulas requires experimental measurements of the parameter n, which depends on the channel bed roughness and also on the physical properties of the liquid flowing in channel.
Examination of level density prescriptions in the interpretation of high energy gamma-ray spectra
Srijit Bhattacharya; Deepak Pandit; Balaram Dey; Debasish Mondal; S. Mukhopadhyay; Surajit Pal; A. De; S. R. Banerjee
High energy $\\gamma$-ray spectra measured by our group involving the compound nuclei (CN) $^{63}$Cu at excitation energy ($E^*$) $\\sim$ 36 MeV with average angular momentum ($J$) = 12 - 17 $\\hbar$, $^{97}$Tc at $E^* \\sim$ 29 - 50 MeV with $J$ = 12 - 14 $\\hbar$, $^{113}$Sb at $E^*$ = 109 MeV and 121 MeV with $J$ = 49 - 59 $\\hbar$ and $^{201}$Tl at $E^*$ = 39.5, 47.5 MeV with $J$ = 18 - 24 $\\hbar$ have been analyzed utilizing the level density prescriptions of (i)Ignatyuk, Smirenkin and Tishin (IST), (ii)Budtz-Jorgensen and Knitter (BJK), and (iii) Kataria, Ramamurthy and Kapoor (KRK). These three prescriptions have been tested for correct statistical model description of high energy $\\gamma$-rays in the light of extracting the giant dipole resonance (GDR) parameters at low excitation energy and spin where shell effects might play an important role as well as at high excitation energy where shell effects have melted. Interestingly, only the IST level density prescription could explain the high energy $\\gamma$-ray spectra with reasonable GDR parameters for all the four nuclei.
Chronic Electromagnetic Exposure at Occupational Safety Level Does Not Affect the Metabolic Profile nor Cornea Healing after LASIK Surgery.
Crouzier, David; Dabouis, Vincent; Gentilhomme, Edgar; Vignal, Rodolphe; Bourbon, Fréderic; Fauvelle, Florence; Debouzy, Jean-Claude
LASIK eye surgery has become a very common practice for myopic people, especially those in the military. Sometimes undertaken by people who need to keep a specific medical aptitude, this surgery could be performed in secret from the hierarchy and from the institute medical staff. However, even though the eyes have been previously described as one of the most sensitive organs to electromagnetic fields in the human body, no data exist on the potential deleterious effects of electromagnetic fields on the healing eye. The consequences of chronic long-lasting radar exposures at power density, in accordance with the occupational safety standards (9.71?GHz, 50?W/m(2)), were investigated on cornea healing. The metabolic and clinical statuses after experimental LASIK keratotomy were assessed on the different eye segments in a New Zealand rabbit model. The analysis methods were performed after 5 months of exposure (1?hour/day, 3 times/week). Neither clinical or histological examinations, nor experimental data, such as light scattering, (1)H-NMR HRMAS metabolomics, (13)C-NMR spectra of lipidic extracts, and antioxidant status, evidenced significant modifications. It was concluded that withdrawing the medical aptitude of people working in electromagnetic field environments (i.e., radar operators in the navy) after eye surgery was not justified. PMID:24757560
Chronic Electromagnetic Exposure at Occupational Safety Level Does Not Affect the Metabolic Profile nor Cornea Healing after LASIK Surgery
Dabouis, Vincent; Gentilhomme, Edgar; Vignal, Rodolphe; Bourbon, Fréderic; Fauvelle, Florence; Debouzy, Jean-Claude
LASIK eye surgery has become a very common practice for myopic people, especially those in the military. Sometimes undertaken by people who need to keep a specific medical aptitude, this surgery could be performed in secret from the hierarchy and from the institute medical staff. However, even though the eyes have been previously described as one of the most sensitive organs to electromagnetic fields in the human body, no data exist on the potential deleterious effects of electromagnetic fields on the healing eye. The consequences of chronic long-lasting radar exposures at power density, in accordance with the occupational safety standards (9.71?GHz, 50?W/m2), were investigated on cornea healing. The metabolic and clinical statuses after experimental LASIK keratotomy were assessed on the different eye segments in a New Zealand rabbit model. The analysis methods were performed after 5 months of exposure (1?hour/day, 3 times/week). Neither clinical or histological examinations, nor experimental data, such as light scattering, 1H-NMR HRMAS metabolomics, 13C-NMR spectra of lipidic extracts, and antioxidant status, evidenced significant modifications. It was concluded that withdrawing the medical aptitude of people working in electromagnetic field environments (i.e., radar operators in the navy) after eye surgery was not justified. PMID:24757560
Some problems of extracting level density and radiative strength functions from the gamma-spectra in nuclear reactions
V. A. Khitrov; A. M. Sukhovoj; Pham Dinh Khang; Vo Thi Anh; Vuong Huu Tan; Nguyen Canh Hai; Nguyen Xuan Hai
The most important systematical errors in determination of level density and radiative strength functions for deformed nuclei have been estimated from the gamma-ray spectra in nuclear reactions like the stripping or pickup reactions.
Research Investigation Directed Toward Extending the Useful Range of the Electromagnetic Spectrum. [atomic spectra and electronic structure of alkali metals
NASA Technical Reports Server (NTRS)
Hartmann, S. R.; Happer, W.
The report discusses completed and proposed research in atomic and molecular physics conducted at the Columbia Radiation Laboratory from July 1972 to June 1973. Central topics described include the atomic spectra and electronic structure of alkali metals and helium, molecular microwave spectroscopy, the resonance physics of photon echoes in some solid state systems (including Raman echoes, superradiance, and two photon absorption), and liquid helium superfluidity.
Phase shift spectra of a fiber-microsphere system at the single photon level
Tanaka, Akira; Toubaru, Kiyota; Takashima, Hideaki; Fujiwara, Masazumi; Okamoto, Ryo; Takeuchi, Shigeki; 10.1364/OE.19.002278
We succeeded in measuring phase shift spectra of a microsphere cavity coupled with a tapered fiber using a weak coherent probe light at the single photon level. We utilized a tapered fiber with almost no depolarization and constructed a very stable phase shift measurement scheme based on polarization analysis using photon counting. Using a very weak probe light (\\bar{n} = 0:41), we succeeded in observing the transition in the phase shift spectrum between undercoupling and overcoupling (at gap distances of 500 and 100 nm, respectively).We also used quantum state tomography to obtain a 'purity spectrum'. Even in the overcoupling regime, the average purity was 0.982 \\pm 0.024 (minimum purity: 0.892), suggesting that the coherence of the fiber-microsphere system was well preserved. Based on these results, we believe this system is applicable to quantum phase gates using single light emitters such as diamond nitrogen vacancy centers.
Phase shift spectra of a fiber-microsphere system at the single photon level
Akira Tanaka; Takeshi Asai; Kiyota Toubaru; Hideaki Takashima; Masazumi Fujiwara; Ryo Okamoto; Shigeki Takeuchi
We succeeded in measuring phase shift spectra of a microsphere cavity coupled with a tapered fiber using a weak coherent probe light at the single photon level. We utilized a tapered fiber with almost no depolarization and constructed a very stable phase shift measurement scheme based on polarization analysis using photon counting. Using a very weak probe light (\\bar{n} = 0:41), we succeeded in observing the transition in the phase shift spectrum between undercoupling and overcoupling (at gap distances of 500 and 100 nm, respectively).We also used quantum state tomography to obtain a 'purity spectrum'. Even in the overcoupling regime, the average purity was 0.982 \\pm 0.024 (minimum purity: 0.892), suggesting that the coherence of the fiber-microsphere system was well preserved. Based on these results, we believe this system is applicable to quantum phase gates using single light emitters such as diamond nitrogen vacancy centers.
Two-dimensional electromagnetically induced cross-grating in a four-level tripod-type atomic system
NASA Astrophysics Data System (ADS)
Wang, Li; Zhou, Fengxue; Hu, Pidong; Niu, Yueping; Gong, Shangqing
By using two orthogonal coupling standing-wave fields, we propose a scheme for a two-dimensional electromagnetically induced cross-grating (EICG) in a four-level tripod-type atomic system. Based on the electromagnetically induced transparency, the probe field will be diffracted and form the two-dimensional EICG through the interaction of the two coupling standing-wave fields. It is shown that the first-order diffraction intensity of the two-dimensional EICG depends observably on the detuning of the probe field and the Rabi frequencies of the two coupling standing-wave fields. The results may be used to develop novel photonic devices for use in quantum information processing, quantum networking and optical imaging.
Electromagnetically induced transparency-assisted four-wave mixing process in the diamond-type four-level atomic system
NASA Astrophysics Data System (ADS)
Wen, Feng; Zheng, Huaibin; Xue, Xinxin; Chen, Haixia; Song, Jianping; Zhang, Yanpeng
With electromagnetically induced transparency (EIT)-assisted configuration, we study the third-order nonlinear four-wave mixing (FWM) process in a diamond-type four-level atomic system both theoretically and experimentally. Following the proposal by the recent study (Willis et al., 2009), we introduce EIT contribution to the theoretical model which will enhance the conversion efficiency of the nonlinear process and narrow the linewidth of the FWM signal. By means of the coherent EIT effect, we get higher conversion efficiency at lower power level of incident beam in such atomic system. Compare to our previous models, the conversion efficiency in such diamond-type atomic system is much smaller which needs higher threshold temperature. In addition, the frequency dependences on incident beams reveal that the dipole transition of one-photon and two-photon processes affect this nonlinear process.
VizieR Online Data Catalog: New FeI level energies from stellar spectra (Peterson+, 2015)
NASA Astrophysics Data System (ADS)
Peterson, R. C.; Kurucz, R. L.
The spectrum of the Fe I atom is critical to many areas of astrophysics and beyond. Measurements of the energies of its high-lying levels remain woefully incomplete, however, despite extensive laboratory and solar analysis. In this work, we use high-resolution archival absorption-line ultraviolet and optical spectra of stars whose warm temperatures favor moderate Fe I excitation. We derive the energy for a particular upper level in Kurucz's semiempirical calculations by adopting a trial value that yields the same wavelength for a given line predicted to be about as strong as that of a strong unidentified spectral line observed in the stellar spectra, then checking the new wavelengths of other strong predicted transitions that share the same upper level for coincidence with other strong observed unidentified lines. To date, this analysis has provided the upper energies of 66 Fe I levels. Many new energy levels are higher than those accessible to laboratory experiments; several exceed the Fe I ionization energy. These levels provide new identifications for over 2000 potentially detectable lines. Almost all of the new levels of odd parity include UV lines that were detected but unclassified in laboratory Fe I absorption spectra, providing an external check on the energy values. We motivate and present the procedure, provide the resulting new energy levels and their uncertainties, list all the potentially detectable UV and optical new Fe I line identifications and their gf values, point out new lines of astrophysical interest, and discuss the prospects for additional Fe I energy level determinations. (3 data files).
Accurate vibrational spectra via molecular tailoring approach: a case study of water clusters at MP2 level.
Sahu, Nityananda; Gadre, Shridhar R
In spite of the recent advents in parallel algorithms and computer hardware, high-level calculation of vibrational spectra of large molecules is still an uphill task. To overcome this, significant effort has been devoted to the development of new algorithms based on fragmentation methods. The present work provides the details of an efficient and accurate procedure for computing the vibrational spectra of large clusters employing molecular tailoring approach (MTA). The errors in the Hessian matrix elements and dipole derivatives arising due to the approximation nature of MTA are reduced by grafting the corrections from a smaller basis set. The algorithm has been tested out for obtaining vibrational spectra of neutral and charged water clusters at Mřller-Plesset second order level of theory, and benchmarking them against the respective full calculation (FC) and/or experimental results. For (H2O)16 clusters, the estimated vibrational frequencies are found to differ by a maximum of 2 cm(-1) with reference to the corresponding FC values. Unlike the FC, the MTA-based calculations including grafting procedure can be performed on a limited hardware, yet take a fraction of the FC time. The present methodology, thus, opens a possibility of the accurate estimation of the vibrational spectra of large molecular systems, which is otherwise impossible or formidable. PMID:25573553
Accurate vibrational spectra via molecular tailoring approach: A case study of water clusters at MP2 level
NASA Astrophysics Data System (ADS)
Sahu, Nityananda; Gadre, Shridhar R.
In spite of the recent advents in parallel algorithms and computer hardware, high-level calculation of vibrational spectra of large molecules is still an uphill task. To overcome this, significant effort has been devoted to the development of new algorithms based on fragmentation methods. The present work provides the details of an efficient and accurate procedure for computing the vibrational spectra of large clusters employing molecular tailoring approach (MTA). The errors in the Hessian matrix elements and dipole derivatives arising due to the approximation nature of MTA are reduced by grafting the corrections from a smaller basis set. The algorithm has been tested out for obtaining vibrational spectra of neutral and charged water clusters at Mřller-Plesset second order level of theory, and benchmarking them against the respective full calculation (FC) and/or experimental results. For (H2O)16 clusters, the estimated vibrational frequencies are found to differ by a maximum of 2 cm-1 with reference to the corresponding FC values. Unlike the FC, the MTA-based calculations including grafting procedure can be performed on a limited hardware, yet take a fraction of the FC time. The present methodology, thus, opens a possibility of the accurate estimation of the vibrational spectra of large molecular systems, which is otherwise impossible or formidable.
A pilot neighborhood study towards establishing a benchmark for reducing electromagnetic field levels within single family residential dwellings.
Richman, Russell; Munroe, Alan James; Siddiqui, Yasmeen
Electromagnetic fields (EMF) permeate the built environment in different forms and come from a number of sources including electrical wiring and devices, wireless communication, 'energy-efficient' lighting, and appliances. It can be present in the indoor environment directly from indoor sources, or can be transmitted through building materials from outside sources. Scientists have identified it as an indoor environmental pollutant or toxin that has ubiquitously plagued developed nations causing a variety of adverse health effects such as sick-building syndrome symptoms, asthma, diabetes, multiple sclerosis, leukemia, electro-hypersensitivity (EHS), behavior disorders, and more. There is currently no international consensus on guidelines and exposure limits. This paper presents the results of 29 EMF field audits in single family residential dwellings located within an urban neighborhood in Toronto (Canada). The following EMF spectra were evaluated: radio frequency, power frequency electric fields, power frequency magnetic fields and high frequency voltage transients. The field audits were conducted in order to provide initial baseline statistics to be used in future studies and in order to be compared to a low-cost EMF reduction design incorporated within the Renovation2050 research house - located within the test neighborhood. The results show the low-cost reduction strategy to be effective, on average reducing exposure by 80% for high-intensity EMF metrics. Research of this nature has not been conducted with relation to the built environment and can be used to spark an industry movement to design for low-exposure to EMF in a residential context. PMID:23962434
Meson exchange effects in elastic ep scattering at loop level and the electromagnetic form factors of the proton
NASA Astrophysics Data System (ADS)
Chen, Hong-Yu; Zhou, Hai-Qing
A new form of two-photon exchange (TPE) effect is studied to explain the discrepancy between unpolarized and polarized experimental data in elastic ep scattering. The mechanism is based on a simple idea that apart from the usual TPE effects from box and crossed-box diagrams, the mesons may also be exchanged in elastic ep scattering by two-photon coupling at loop level. The detailed study shows such contributions to reduced unpolarized cross section (?un) and polarized observables (Pt,Pl) at fixed Q2 are only dependent on proton's electromagnetic form factors GE ,M and a new unknown universal parameter g. After combining this contribution with the usual TPE contributions from box and crossed-box diagrams, the ratio ?pGE/GM extracted from the recent precise unpolarized and polarized experimental data can be described consistently.
The Effects of Electromagnetic Fields Generated from 1800 MHz Cell Phones on Erythrocyte Rheological Parameters and Zinc Level in Rats
Erken, Gülten; Küçükatay, Melek Bor; Turgut, Sebahat; Erken, Haydar Ali; Çömlekçi, Selçuk; Divrikli, Ümit; Genç, Osman
Objective: The aim of this study was to investigate the effects of the electromagnetic field generated from the 1800 MHz radiofrequency radiation (EF) on erythrocyte rheological parameters and erythrocyte zinc levels. Material and Methods: Twenty-four male Wistar Albino rats were randomly grouped as follows: 1) two control groups and 2) study groups: i) Group A: EF exposed group (2.5 h/day for 30 days, the phone on stand-by), and ii) Group B: EF exposed group (2.5 min/day for 30 days, the phone ringing in silent mode). At the end of the experimental period erythrocyte rheological parameters such as erythrocyte deformability and aggregation were determined by an ectacytometer. Erythrocyte zinc level, which affects hemorheological parameters, was also measured by atomic absorption spectrophotometer. Results: Erythrocyte deformability was decreased in both study groups but the decrease in group A was not statistically significant. Exposure to EF did not have any significant effect on erythrocyte aggregation. On the other hand, erythrocyte zinc level was significantly reduced in both study groups. Conclusion: Exposure to EF may have decreased tissue oxygenation due to reduced erythrocyte deformability. Decrease in erythrocyte zinc level may have caused the impairment in erythrocyte deformability. PMID:25206983
Coincident Observation of Lightning using Spaceborne Spectrophotometer and Ground-Level Electromagnetic Sensors
NASA Technical Reports Server (NTRS)
Adachi, Toru; Cohen, Morris; Li, Jingbo; Cummer, Steve; Blakeslee, Richard; Marshall, THomas; Stolzenberg, Maribeth; Karunarathne, Sumedhe; Hsu, Rue-Ron; Su, Han-Tzong; Chen, Alfred; Takahashi, Yukihiro; Frey, Harald; Mende, Stephen
The present study aims at assessing a possible new way to reveal the properties of lightning flash, using spectrophotometric data obtained by FORMOSAT-2/ISUAL which is the first spaceborne multicolor lightning detector. The ISUAL data was analyzed in conjunction with ground ]based electromagnetic data obtained by Duke magnetic field sensors, NLDN, North Alabama Lightning Mapping Array (LMA), and Kennedy Space Center (KSC) electric field antennas. We first classified the observed events into cloud ]to ]ground (CG) and intra ]cloud (IC) lightning based on the Duke and NLDN measurements and analyzed ISUAL data to clarify their optical characteristics. It was found that the ISUAL optical waveform of CG lightning was strongly correlated with the current moment waveform, suggesting that it is possible to evaluate the electrical properties of lightning from satellite optical measurement to some extent. The ISUAL data also indicated that the color of CG lightning turned to red at the time of return stroke while the color of IC pulses remained unchanged. Furthermore, in one CG event which was simultaneously detected by ISUAL and LMA, the observed optical emissions slowly turned red as the altitude of optical source gradually decreased. All of these results indicate that the color of lightning flash depends on the source altitude and suggest that spaceborne optical measurement could be a new tool to discriminate CG and IC lightning. In the presentation, we will also show results on the comparison between the ISUAL and KSC electric field data to clarify characteristics of each lightning process such as preliminary breakdown, return stroke, and subsequent upward illumination.
Two Electromagnetically Induced Transparency Windows and Cross-Phase Modulation with Four-Level Superconducting Artificial Atoms
NASA Astrophysics Data System (ADS)
Alotaibi, Hessa; Sanders, Barry
Superconducting circuit quantum electrodynamics (SCQED) employs microwave transmission lines coupled to artificial atoms, which are typical two-level and recently three-level for electromagnetically induced transparency (EIT). We propose SCQED with a four-level tripod-configuration artificial atom to enable cross-phase modulation between two traveling-wave microwave fields. Our master-equation analysis for three driving fields (``signal,'' ``probe'' and ``coupling'') demonstrates the existence of two distinct EIT transparency windows in the spectral-response profile as a function of coupling and weak fields strength. We provide the first theoretical analysis of this unexpected second window and show its advantages over the known first EIT window. Specifically we show that this second EIT window provides both the signal and probe fields with identical response functions provided that their Rabi frequencies and detunings are the same. Exploiting the second window with judiciously chosen external flux and energy detuning result in low absorption, excellent group velocity matching, and high nonlinearity, thereby enabling strong cross-phase modulation for SCQED.
Variability in electromagnetic field levels over time, and Monte-Carlo simulation of exposure parameters.
Pachón-García, F T; Paniagua-Sánchez, J M; Rufo-Pérez, M; Jiménez-Barco, A
This article analyses the electric field levels around medium-wave transmitters, delimiting the temporal variability of the levels received at a pre-established reception point. One extensively used dosimetric criterion is to consider historical levels of the field recorded over a certain period of time so as to provide an overall perspective of radio-frequency electric field exposure in a particular environment. This aspect is the focus of the present study, in which the measurements will be synthesised in the form of exposure coefficients. Two measurement campaigns were conducted: one short term (10 days) and the other long term (1 y). The short-term data were used to study which probability density functions best approximate the measured levels. The long-term data were used to compute the principal statistics that characterise the field values over a year. The data that form the focus of the study are the peak traces, since these are the most representative from the standpoint of exposure. The deviations found were around 6 % for short periods and 12 % for long periods. The information from the two campaigns was used to develop and implement a computer application based on the Monte Carlo method to simulate values of the field, allowing one to carry out robust statistics. PMID:24594905
Quantum Dynamics of Two-Level Atoms Interacting with AN Electromagnetic Field
NASA Astrophysics Data System (ADS)
Bogolubov, N. N.; Yu. Rasulova, M.; Tishaboev, I. A.
We consider the dynamics of a system consisting of N two-level atoms interacting with a multi-mode cavity field. For the given system, the generalized kinetic equation (GKE) is obtained and conditions are given under which its solution is reduced to solution of a linear equation, and of the one-dimensional nonlinear Schrödinger equation, respectively.
Effect of Extremely Low Frequency Electromagnetic Field and GABAA Receptors on Serum Testosterone Level of Male Rats
Taherianfard, Mahnaz; Bahaddini, Aminolah; Keshtkar, Sara; Fazeli, Mehdi; Shomali, Tahora
Background: GABA can influence the steroidogenesis in peripheral and central nervoussystems. Objectives: The present study investigates the interactive effect of GABAA receptors and extremely low frequency electromagnetic field on serum testosterone level of male rats. Patients and Methods: Fifty adult male rats were randomly assigned into 10 groups. Groups 2, 4, 6, 8, and 10 were exposed to ELF-EMF for 30 days 8hrs per day; while, the remaining groups (1, 3, 5, 7, and 9) were sham exposed animals. At the end of the experiment, animals in groups 1 and 2 received normal saline; while, animals in groups 3 and 4 were treated with 1 mg/kg of bicuculline methiodide, and for animals of groups 5 and 6,3 mg/kg of bicuculline was injected. Animals of groups 7 and 8 were treated with 0.5 mg/kg of muscimol hydrobromide and rats in groups 9 and 10 received 2 mg/kg muscimol hydrobromide. About forty minutes after the injection, blood samples were collected and serum testosterone level was assayed using RIA. Results: Administration of muscimol hydrobromide at both doses to sham exposed rats significantly decreased serum testosterone level as compared to sham exposed animals which received saline. Administration of bicuculline methiodide without exposure to ELF-EMF, had no significant effect on testosterone level as compared to group 1. Serum testosterone levels of rats in different groups, exposed to ELF-EMF were statistically the same. Moreover, serum testosterone of exposed and sham exposed rats in each treatment showed no significant difference. Conclusions: No interactivity is present in modulatory effects of GABAA receptors and ELF-EMFs on serum testosterone of male rats. PMID:24719627
Electromagnetic energy as a bridge between atomic and cellular levels in the genetics approach to cancer treatment.
Tofani, Santi
Literature on magnetic fields (MF) and gene expression, as well as on DNA damage, supports the hypothesis that electromagnetic energy may act at atomic level influencing genetic stability. According to quantum physics, MF act on the interconversion of singlet and triplet spin states, and therefore on genetic instability, activating oxidative processes connected to biological free radicals formation, particularly ROS. In the above frame, the results of in vitro and in vivo laboratory trials have been analyzed. The use of a static MF amplitude modulated by 50 Hz MF, with a time average total intensity of 5.5 mT, has been shown to influence tumor cell functions such as cell proliferation, apoptosis, p53 expression, inhibition of tumor growth and prolongation of survival in animals, evidence that MF can be more effective than chemotherapy (cyclophosphamide) in inhibiting metastatic spread and growth, having synergistic activity with chemotherapy (Cis-platin), and no observable side effects or toxicity in animals or in humans. The beneficial biological/clinical effects observed, without any adverse effects, have been confirmed by various authors and augur well for the potentiality of this new approach to treat genetically based diseases like cancer. Further studies are needed to develop a quantum physics approach to biology, allowing a stable bridge to be built between atomic and cellular levels, therefore developing quantum biology. PMID:25714380
Impact of 900 MHz electromagnetic field exposure on main male reproductive hormone levels: a Rattus norvegicus model
NASA Astrophysics Data System (ADS)
Sepehrimanesh, Masood; Saeb, Mehdi; Nazifi, Saeed; Kazemipour, Nasrin; Jelodar, Gholamali; Saeb, Saeedeh
This work analyzes the effects of radiofrequency-electromagnetic field (RF-EMF) exposure on the reproductive system of male rats, assessed by measuring circulating levels of FSH, LH, inhibin B, activin B, prolactin, and testosterone. Twenty adult male Sprague-Dawley rats (180 ± 10 g) were exposed to 900 MHz RF-EMF in four equal separated groups. The duration of exposure was 1, 2, and 4 h/day over a period of 30 days and sham-exposed animals were kept under the same environmental conditions as the exposed group except with no RF-EMF exposure. Before the exposure, at 15 and 30 days of exposure, determination of the abovementioned hormone levels was performed using ELISA. At the end of the experiment, FSH and LH values of the long time exposure (LTE) group were significantly higher than the sham-exposed group ( p < 0.05). Serum activin B and prolactin in the LTE group showed significant increase and inhibin B showed significant decrease than sham and short time exposed (STE) groups after 30 days RF-EMF exposure ( p < 0.05). Also, a significant decrease in serum testosterone levels in the LTE group was found compared to short and moderate time exposed (MTE) groups after 30 days RF-EMF exposure ( p < 0.05). Results suggest that reproductive hormone levels are disturbed as a result of RF-EMF exposure and it may possibly affect reproductive functions. However, testosterone and inhibin B concentrations as a fertility marker and spermatogenesis were decreased significantly.
Impact of 900 MHz electromagnetic field exposure on main male reproductive hormone levels: a Rattus norvegicus model.
Sepehrimanesh, Masood; Saeb, Mehdi; Nazifi, Saeed; Kazemipour, Nasrin; Jelodar, Gholamali; Saeb, Saeedeh
This work analyzes the effects of radiofrequency-electromagnetic field (RF-EMF) exposure on the reproductive system of male rats, assessed by measuring circulating levels of FSH, LH, inhibin B, activin B, prolactin, and testosterone. Twenty adult male Sprague-Dawley rats (180?±?10 g) were exposed to 900 MHz RF-EMF in four equal separated groups. The duration of exposure was 1, 2, and 4 h/day over a period of 30 days and sham-exposed animals were kept under the same environmental conditions as the exposed group except with no RF-EMF exposure. Before the exposure, at 15 and 30 days of exposure, determination of the abovementioned hormone levels was performed using ELISA. At the end of the experiment, FSH and LH values of the long time exposure (LTE) group were significantly higher than the sham-exposed group (p?0.05). Serum activin B and prolactin in the LTE group showed significant increase and inhibin B showed significant decrease than sham and short time exposed (STE) groups after 30 days RF-EMF exposure (p?0.05). Also, a significant decrease in serum testosterone levels in the LTE group was found compared to short and moderate time exposed (MTE) groups after 30 days RF-EMF exposure (p?0.05). Results suggest that reproductive hormone levels are disturbed as a result of RF-EMF exposure and it may possibly affect reproductive functions. However, testosterone and inhibin B concentrations as a fertility marker and spermatogenesis were decreased significantly. PMID:24357488
Nuclear level densities in 47V, 48V, 49V, 53Mn, and 54Mn from neutron evaporation spectra
NASA Astrophysics Data System (ADS)
Zhuravlev, B. V.; Lychagin, A. A.; Titarenko, N. N.; Demenkov, V. G.; Trykova, V. I.
The spectra of neutrons from the ( p, n) reactions on 47Ti, 48Ti, 49Ti, 53Cr, and 54Cr nuclei were measured in the proton-energy range 7-11 MeV. The measurements were performed with the aid of a fast-neutron spectrometer by the time-of-flight method over the base of the EGP-15 tandem accelerator of the Institute for Physics and Power Engineering (IPPE, Obninsk). Owing to a high resolution and a high stability of the time-of-flight spectrometer used, low-lying discrete levels could be identified reliably along with a continuum section of neutron spectra. An analysis of measured data was performed within the statistical equilibrium and preequilibrium models of nuclear reactions. The relevant calculations were performed by using the exact formalism of Hauser-Feshbach statistical theory supplemented with the generalized model of a superfluid nucleus, the back-shifted Fermi gas model, and the Gilbert-Cameron composite formula for the nuclear level density. The nuclear level densities for 47V, 48V, 49V, 53Mn, and 54Mn were determined along with their energy dependences and model parameters. The results are discussed together with available experimental data and recommendations of model systematics.
Nuclear magnetic resonance inverse spectra of InGaAs quantum dots: Atomistic level structural information
NASA Astrophysics Data System (ADS)
Bulutay, Ceyhun; Chekhovich, E. A.; Tartakovskii, A. I.
A wealth of atomistic information is contained within a self-assembled quantum dot (QD), associated with its chemical composition and the growth history. In the presence of quadrupolar nuclei, as in InGaAs QDs, much of this is inherited to nuclear spins via the coupling between the strain within the polar lattice and the electric quadrupole moments of the nuclei. Here, we present a computational study of the recently introduced inverse spectra nuclear magnetic resonance technique to assess its suitability for extracting such structural information. We observe marked spectral differences between the compound InAs and alloy InGaAs QDs. These are linked to the local biaxial and shear strains, and the local bonding configurations. The cation alloying plays a crucial role especially for the arsenic nuclei. The isotopic line profiles also largely differ among nuclear species: While the central transition of the gallium isotopes have a narrow linewidth, those of arsenic and indium are much broader and oppositely skewed with respect to each other. The statistical distributions of electric field gradient (EFG) parameters of the nuclei within the QD are analyzed. The consequences of various EFG axial orientation characteristics are discussed. Finally, the possibility of suppressing the first-order quadrupolar shifts is demonstrated by simply tilting the sample with respect to the static magnetic field.
Nuclear magnetic resonance inverse spectra of InGaAs quantum dots: Atomistic level structural information
Ceyhun Bulutay; E. A. Chekhovich; A. I. Tartakovskii
A wealth of atomistic information is contained within a self-assembled quantum dot (QD), associated with its chemical composition and the growth history. In the presence of quadrupolar nuclei, as in InGaAs QDs, much of this is inherited to nuclear spins via the coupling between the strain within the polar lattice and the electric quadrupole moments of the nuclei. Here, we present a computational study of the recently introduced inverse spectra nuclear magnetic resonance technique to assess its suitability for extracting such structural information. We observe marked spectral differences between the compound InAs and alloy InGaAs QDs. These are linked to the local biaxial and shear strains, and the local bonding configurations. The cation-alloying plays a crucial role especially for the arsenic nuclei. The isotopic line profiles also largely differ among nuclear species: While the central transition of the gallium isotopes have a narrow linewidth, those of arsenic and indium are much broader and oppositely skewed with respect to each other. The statistical distributions of electric field gradient (EFG) parameters of the nuclei within the QD are analyzed. The consequences of various EFG axial orientation characteristics are discussed. Finally, the possibility of suppressing the first-order quadrupolar shifts is demonstrated by simply tilting the sample with respect to the static magnetic field.
Spectra-structure correlations in solid metal saccharinates. II. Ab initio molecular structures and vibrational spectra of N-substituted saccharins at the HF level
NASA Astrophysics Data System (ADS)
Naumov, Pan?e; Jovanovski, Gligor; Ohashi, Yuji
Ground-state ab initio molecular geometries and vibrational spectra of 24 N-substituted isolated saccharins with small-size B, Br, C, Cl, F, N, O, P or S-groups and the parent molecule are predicted at RHF/6-31G level to examine the molecular structural changes stemming from N-substitution of saccharin (o-sulfobenzimide). Trends in the molecular geometrical parameters of the sulfimide ring and the carbonyl stretching frequency are discussed in relation to the electronic properties of the substituent and the solid state effects. The results are compared with the crystallographic data for N-substituted saccharins and metal saccharinato salts/complexes retrieved from the Cambridge Structural Database. The ability of several theoretical methods to describe the substitution/deprotonation of the conjugated CO?NH?SO 2 structure is summarized. Electronic properties of the substituent affect significantly only the immediate C?N and S?N bonds by as much as ±0.014 Ĺ, while other bonds are relatively less influenced (±0.004 Ĺ). Combined with the effects of the crystal packing and thermal vibrations, they impose flexibility on the intramolecular lengths up to ±0.02 Ĺ. High correlation ( R=0.966) between the theoretical ?(CO) frequencies and C?O distances is predictable for both of these parameters, but is lowered notably in the crystal by both vibrational and solid-state circumstances. From the structural viewpoint, the N sac-X bonds (X = B, Br, C, Cl, F, N, O, P, S; sac denotes saccharin) behave similarly to the purely covalent N sac-metal bonds.
A new tool for hillslope hydrologists: spatially distributed groundwater level and soilwater content measured using electromagnetic induction
NASA Astrophysics Data System (ADS)
Sherlock, Mark D.; McDonnell, Jeffrey J.
New methods for obtaining and quantifying spatially distributed subsurface moisture are a high research priority in process hydrology. We use simple linear regression analyses to compare terrain electrical conductivity measurements (EC) derived from multiple electromagnetic induction (EMI) frequencies to a distributed grid of water-table depth and soil-moisture measurements in a highly instrumented 50 by 50 m hillslope in Putnam County, New York. Two null hypotheses were tested: H0(1), there is no relationship between water table depth and EC; H0(2), there is no relationship between soil moisture levels and EC. We reject both these hypotheses. Regression analysis indicates that EC measurements from the low frequency EM31 meter with a vertical dipole orientation could explain over 80% of the variation in water-table depth across the test hillslope. Despite zeroing and sensitivity problems encountered with the high frequency EM38, EC measurements could explain over 70% of the gravimetrically determined soil-moisture variance. The use of simple moisture retrieval algorithms, which combined EC measurements from the EM31 and EM38 meters in both their vertical and horizontal orientations, helped increase the r2 coefficients slightly. This first hillslope hydrological analysis of EMI technology in this way suggests that it may be a promising method for the collection of a large number of distributed soilwater and groundwater depth measurements with a reasonable degree of accuracy.
Effects of simultaneous combined exposure to CDMA and WCDMA electromagnetic fields on serum hormone levels in rats
Jin, Yeung Bae; Choi, Hyung-Do; Kim, Byung Chan; Pack, Jeong-Ki; Kim, Nam; Lee, Yun-Sil
Despite more than a decade of research on the endocrine system, there have been no published studies about the effects of concurrent exposure of radiofrequency electromagnetic fields (RF-EMF) on this system. The present study investigated the several parameters of the endocrine system including melatonin, thyroid stimulating hormone, stress hormone and sex hormone after code division multiple access (CDMA, 849 MHz) and wideband code division multiple access (WCDMA, 1.95 GHz) signals for simultaneous exposure in rats. Sprague-Dawley rats were exposed to RF-EMF signals for 45 min/day, 5 days/week for up to 8 weeks. The whole-body average specific absorption rate (SAR) of CDMA or WCDMA was 2.0 W/kg (total 4.0 W/kg). At 4 and 8 weeks after the experiment began, each experimental group's 40 rats (male 20, female 20) were autopsied. Exposure for 8 weeks to simultaneous CDMA and WCDMA RF did not affect serum levels in rats of melatonin, thyroid stimulating hormone (TSH), triiodothyronine (T3) and thyroxin (T4), adrenocorticotropic hormone (ACTH) and sex hormones (testosterone and estrogen) as assessed by the ELISA method. PMID:23239176
Levels of Ambrosia pollen in the atmospheric spectra of Catalan aerobiological stations
Jordina Belmonte; Mercč Vendrell; Joan M. Roure; Josep Vidal; Jaume Botey; Ŕlvar Cadahía
Ambrosia pollen is known as an importantallergen in North America, and more recently in someEuropean countries. From 1989 to 1995, the Ambrosia pollen levels detected at the stationsmonitored by the Aerobiological Network of Catalonia(Xarxa Aerobiolňgica de Catalunya, XAC) wereinsignificant. In 1996, a considerable althoughtemporary increase in the concentration of this pollenwas detected in the atmosphere over Girona, Barcelona,Bellaterra, Manresa, and
Saturation-induced distortion of four-wave-mixing spectra in a two-level system
A. D. Wilson-Gordon; H. Friedmann
It is shown that saturation causes the three-peaked four-wave-mixing (FWM) signal at frequency 2omega1-omega2, obtained from the interaction of a two-level system with a ``probe'' laser of varying frequency omega2 and a ``pump'' laser of fixed frequency omega1, to become asymmetrical on increasing the probe-laser intensity. Whereas saturation peaks occur in the population-inversion spectrum at one-photon and multiphoton resonances, this
Extremely Low-Frequency Electromagnetic Fields Affect Transcript Levels of Neuronal Differentiation-Related Genes in Embryonic Neural Stem Cells
Ma, Qinlong; Deng, Ping; Zhu, Gang; Liu, Chuan; Zhang, Lei; Zhou, Zhou; Luo, Xue; Li, Min; Zhong, Min; Yu, Zhengping; Chen, Chunhai; Zhang, Yanwen
Previous studies have reported that extremely low-frequency electromagnetic fields (ELF-EMF) can affect the processes of brain development, but the underlying mechanism is largely unknown. The proliferation and differentiation of embryonic neural stem cells (eNSCs) is essential for brain development during the gestation period. To date, there is no report about the effects of ELF-EMF on eNSCs. In this paper, we studied the effects of ELF-EMF on the proliferation and differentiation of eNSCs. Primary cultured eNSCs were treated with 50 Hz ELF-EMF; various magnetic intensities and exposure times were applied. Our data showed that there was no significant change in cell proliferation, which was evaluated by cell viability (CCK-8 assay), DNA synthesis (Edu incorporation), average diameter of neurospheres, cell cycle distribution (flow cytometry) and transcript levels of cell cycle related genes (P53, P21 and GADD45 detected by real-time PCR). When eNSCs were induced to differentiation, real-time PCR results showed a down-regulation of Sox2 and up-regulation of Math1, Math3, Ngn1 and Tuj1 mRNA levels after 50 Hz ELF-EMF exposure (2 mT for 3 days), but the percentages of neurons (Tuj1 positive cells) and astrocytes (GFAP positive cells) were not altered when detected by immunofluorescence assay. Although cell proliferation and the percentages of neurons and astrocytes differentiated from eNSCs were not affected by 50 Hz ELF-EMF, the expression of genes regulating neuronal differentiation was altered. In conclusion, our results support that 50 Hz ELF-EMF induce molecular changes during eNSCs differentiation, which might be compensated by post-transcriptional mechanisms to support cellular homeostasis. PMID:24595264
Exact results for the spectra of interacting bosons and fermions on the lowest Landau level
NASA Astrophysics Data System (ADS)
Mashkevich, Stefan; Matveenko, Sergey; Ouvry, Stéphane
A system of N interacting bosons or fermions in a two-dimensional harmonic potential (or, equivalently, magnetic field) whose states are projected onto the lowest Landau level is considered. Generic expressions are derived for the matrix elements of any interaction, in the basis of angular momentum eigenstates. For the fermion 'ground state' (? = 1 Laughlin state), this makes it possible to exactly calculate its energy all the way up to the mesoscopic regime N ? 1000. It is also shown that for N = 3 and Coulomb interaction, several rational low-lying values of energy exist, for bosons and fermions alike.
Model calculation of core level XPS spectra in early 3d-metal compounds
NASA Astrophysics Data System (ADS)
Parlebas, J. C.
Using a configuration-interaction impurity-Anderson model we calculate core-hole X-ray Photoemission Spectra (c-XPS) for some early Transition Metal (TM) insulating compounds. Because in these compounds the valence (ligand) band is completely filled, the TM on-site Coulomb repulsion U_dd is treated exactly, as well as the 3d-core hole interaction U_dc. The ground state of such a ligand-TM system with a nominally d^0 cation is described as a mixture of purely d^0 ionic state, and charge-transfer screened d^1L and d^2L^2 states where L denotes a hole in the ligand band. Our simplified model enables us to understand why c-XPS satellites are still present in CaF2 or CaO, like in light TM compounds, but absent for KF compounds. In addition to U_dd and U_dc, the other relevant parameters are the ligand-to-metal charge-transfer energy ? and the corresponding hybridization V (related to the metal-ligand transfer integrals). Finally quite a good fit to 2p{3/2}-XPS of TiO2 is obtained by using the parameter values estimated from (i) a LMTO band structure calculation of TiO2, and (ii) another calculated fit of the K(Ti) pre-edge absorption spectrum in TiO2. A l'aide du modčle d'impureté d'Anderson avec mélange de configurations, nous calculons les spectres X de la photoémission de cśur (c-XPS) pour certains composés isolants du début de la série des métaux de transition (MT). Comme la bande de valence de ces composés est complčtement remplie, on peut traiter exactement la répulsion de Coulomb U_dd sur le site du MT ainsi d'ailleurs que l'interaction U_dc entre l'électron 3d et le trou de cśur. L'état de base d'un tel systčme contenant un cation de configuration d^0 est décrit par un mélange de l'état ionique purement d^0 et des états écrantés ŕ transfert de charge d^1L et d^2L^2 oů L est mis pour un trou dans la bande de valence. Ce modčle trčs simplifié est par exemple capable de comprendre pourquoi les satellites de la photoémission de cśur sont bien présents dans CaF2 ou CaO, comme dans les composés de MT légers, mais absents dans les composés KF. En plus de U_dd et U_dc, les autres paramčtres pertinents sont ?, l'énergie de transfert de charge du métalloďde vers le métal et l'hybridation correspondante V (reliée aux intégrales de transferts correspondantes). Aussi, nous avons pu obtenir un bon ajustement théorique du spectre 2p{3/2}-XPS, mesuré dans TiO2, et ceci en utilisant les valeurs des paramčtres fournies par (i) un calcul de structure de bandes LMTO de TiO2, (ii) un calcul des prépics du seuil K(Ti) d'absorption dans TiO2.
High-level ab initio computations of the absorption spectra of organic iridium complexes.
Plasser, Felix; Dreuw, Andreas
The excited states of fac-tris(phenylpyridinato)iridium [Ir(ppy)3] and the smaller model complex Ir(C3H4N)3 are computed using a number of high-level ab initio methods, including the recently implemented algebraic diagrammatic construction method to third-order ADC(3). A detailed description of the states is provided through advanced analysis methods, which allow a quantification of different charge transfer and orbital relaxation effects and give extended insight into the many-body wave functions. Compared to the ADC(3) benchmark an unexpected striking difference of ADC(2) is found for Ir(C3H4N)3, which derives from an overstabilization of charge transfer effects. Time-dependent density functional theory (TDDFT) using the B3LYP functional shows an analogous but less severe error for charge transfer states, whereas the ?B97 results are in good agreement with ADC(3). Multireference configuration interaction computations, which are in reasonable agreement with ADC(3), reveal that static correlation does not play a significant role. In the case of the larger Ir(ppy)3 complex, results at the TDDFT/B3LYP and TDDFT/?B97 levels of theory are presented. Strong discrepancies between the two functionals, which are found with respect to the energies, characters, as well as the density of the low lying states, are discussed in detail and compared to experiment. PMID:25584785
Analysis of High Cadence In Situ Solar Wind Ionic Composition Data Using Wavelet Power Spectra Confidence Levels
NASA Astrophysics Data System (ADS)
Edmondson, J. K.; Lynch, B. J.; Lepri, S. T.; Zurbuchen, T. H.
The variability inherent in solar wind composition has implications for the variability of the physical conditions in its coronal source regions, providing constraints on models of coronal heating and solar wind generation. We present a generalized prescription for constructing a wavelet power significance measure (confidence level) for the purpose of characterizing the effects of missing data in high cadence solar wind ionic composition measurements. We describe the data gaps present in the 12 minute Advanced Composition Explorer/Solar Wind Ionic Composition Spectrometer observations of O7 +/O6 + during 2008. The decomposition of the in situ observations into "good measurement" and "no-measurement" signals allows us to evaluate the performance of a filler signal, i.e., various prescriptions for filling the data gaps. We construct Monte Carlo simulations of synthetic O7 +/O6 + composition data and impose the actual data gaps that exist in the observations in order to investigate two different filler signals: one, a linear interpolation between neighboring good data points, and two, the constant mean value of the measured data. Applied to these synthetic data plus filler signal combinations, we quantify the ability of the power spectra significance level procedure to reproduce the ensemble-averaged time-integrated wavelet power per scale of an ideal case, i.e., the synthetic data without imposed data gaps. Finally, we present the wavelet power spectra for the O7 +/O6 + data using the confidence levels derived from both the mean value and linear interpolation data gap filling signals and discuss the results.
Predicting foliar biochemistry of tea (Camellia sinensis) using reflectance spectra measured at powder, leaf and canopy levels
NASA Astrophysics Data System (ADS)
Bian, Meng; Skidmore, Andrew K.; Schlerf, Martin; Wang, Tiejun; Liu, Yanfang; Zeng, Rong; Fei, Teng
Some biochemical compounds are closely related with the quality of tea (Camellia sinensis (L.)). In this study, the concentration of these compounds including total tea polyphenols, free amino acids and soluble sugars were estimated using reflectance spectroscopy at three different levels: powder, leaf and canopy, with partial least squares regression. The focus of this study is to systematically compare the accuracy of tea quality estimations based on spectroscopy at three different levels. At the powder level, the average r2 between predictions and observations was 0.89 for polyphenols, 0.81 for amino acids and 0.78 for sugars, with relative root mean square errors (RMSE/mean) of 5.47%, 5.50% and 2.75%, respectively; at the leaf level, the average r2 decreased to 0.46-0.81 and the relative RMSE increased to 4.46-7.09%. Compared to the results yielded at the leaf level, the results from canopy spectra were slightly more accurate, yielding average r2 values of 0.83, 0.77 and 0.56 and relative RMSE of 6.79%, 5.73% and 4.03% for polyphenols, amino acids and sugars, respectively. We further identified wavelength channels that influenced the prediction model. For powder and leaves, some bands identified can be linked to the absorption features of chemicals of interest (1648 nm for phenolic, 1510 nm for amino acids, 2080 nm and 2270 nm for sugars), while more indirectly related wavelengths were found to be important at the canopy level for predictions of chemical compounds. Overall, the prediction accuracies achieved at canopy level in this study are encouraging for future study on tea quality estimated at the landscape scale using airborne and space-borne sensors.
Sharing the protection of aircraft electronic systems against the effects of high-level electromagnetic environments between traditional protection and system architecture
NASA Astrophysics Data System (ADS)
Hess, Richard F.; Yount, Larry J.; Knoller, Henry; Masson, Gerald M.; Larsen, William E.
It is shown how architectural techniques can be used as a complement to traditional protection techniques to provide additional protection of sensitive avionics against high-level electromagnetic fields. Consideration is given to potential threats, the data processor susceptibility response, protection from the threat, system architecture, and transparent recovery. The wave shape of engineering waveforms that reproduce important lightning waveform parameters (amplitude, rise time, and action integral) is presented.
Noise levels, spectra, and operational function of an occupied newborn intensive care unit built to meet recommended permissible noise criteria
NASA Astrophysics Data System (ADS)
Philbin, M. Kathleen; Evans, Jack B.
A group of clinical experts developed recommended permissible noise criteria for newly constructed or renovated hospital nurseries [Philbin et al., J. Perinatol. 19, 559-563 (2000); R. White, ibid. 23, S1-22 (2003)]. These criteria are based principally on research regarding wake-up thresholds for term newborns and speech interference levels for adults. These criteria are: The overall continuous A-weighted, slow response, sound level at any bed or patient care area shall not exceed: (1) an hourly Leq of 50 dB, (2) an hourly L10 of 55 dB, and (3) a 1-s Lmax of 70 dB. A new hospital building was designed to meet these criteria by using specific acoustical criteria for the structure and space arrangement [J. B. Evans and M. K. Philbin, J. Perinatol. 20, S105-S112 (2000)]. Acoustical criteria for sound isolation, background NC, structural vibration, and reverberation will be presented along with space arrangements that ensure staff efficiency, clinical safety, and family privacy. Post-occupancy measurements of sound levels and spectra along with photographs of a nursery in operation will be presented to illustrate how an ICU can have a quiet, highly functioning intensive care environment while meeting the operational goals and acoustical criteria.
Estimation of maximum permissible errors in the total gamma-spectra intensities at determination from them of level density and radiative strength functions
A. M. Sukhovoj; V. A. Khitrov
From a comparison of the total gamma-spectra calculated for different functional dependencies of level density and radiative strength functions, there were obtained both their square root relative differences and analogous data for the used parameters. The analysis of these data showed that the total uncertainty in determination of gamma-spectra intensities which is necessary to obtain reliable values of parameters of cascade gamma-decay, most probably, must not exceed one percent.
OptaDOS: A tool for obtaining density of states, core-level and optical spectra from electronic structure codes
NASA Astrophysics Data System (ADS)
Morris, Andrew J.; Nicholls, Rebecca J.; Pickard, Chris J.; Yates, Jonathan R.
We present OptaDOS, a program for calculating core-electron and low-loss electron energy loss spectra (EELS) and optical spectra along with total-, projected- and joint-density of electronic states (DOS) from single-particle eigenenergies and dipole transition coefficients. Energy-loss spectroscopy is an important tool for probing bonding within a material. Interpreting these spectra can be aided by first principles calculations. The spectra are generated from the eigenenergies through integration over the Brillouin zone. An important feature of this code is that this integration is performed using a choice of adaptive or linear extrapolation broadening methods which we show produces higher accuracy spectra than standard fixed-width Gaussian broadening. OptaDOS may be straightforwardly interfaced to any electronic structure code. OptaDOS is freely available under the GNU General Public licence from http://www.optados.org.
IR Spectroscopy Spectroscopy: Branch of science in which light or other electromagnetic radiation
Sherrill, David
IR Spectroscopy Spectroscopy: Branch of science in which light or other electromagnetic radiation the energy difference of 2 quantum levels of the sample of matter. hE = IR Spectroscopy Tool for examining vibrations in molecules. IR spectra are usually taken in the range mµ 0.155.2~ - , which corresponds
Electromagnetism, Second Edition
NASA Astrophysics Data System (ADS)
Grant, I. S.; Phillips, W. R.
The Manchester Physics Series General Editors: D. J. Sandiford; F. Mandl; A. C. Phillips Department of Physics and Astronomy, University of Manchester Properties of Matter B. H. Flowers and E. Mendoza Optics Second Edition F. G. Smith and J. H. Thomson Statistical Physics Second Edition F. Mandl Electromagnetism Second Edition I. S. Grant and W. R. Phillips Statistics R. J. Barlow Solid State Physics Second Edition J. R. Hook and H. E. Hall Quantum Mechanics F. Mandl Particle Physics Second Edition B. R. Martin and G. Shaw the Physics of Stars Second Edition A. C. Phillips Computing for Scientists R. J. Barlow and A. R. Barnett Electromagnetism, Second Edition is suitable for a first course in electromagnetism, whilst also covering many topics frequently encountered in later courses. The material has been carefully arranged and allows for flexi-bility in its use for courses of different length and structure. A knowledge of calculus and an elementary knowledge of vectors is assumed, but the mathematical properties of the differential vector operators are described in sufficient detail for an introductory course, and their physical significance in the context of electromagnetism is emphasised. In this Second Edition the authors give a fuller treatment of circuit analysis and include a discussion of the dispersion of electromagnetic waves. Electromagnetism, Second Edition features: The application of the laws of electromagnetism to practical problems such as the behaviour of antennas, transmission lines and transformers. Sets of problems at the end of each chapter to help student understanding, with hints and solutions to the problems given at the end of the book. Optional "starred" sections containing more specialised and advanced material for the more ambitious reader. An Appendix with a thorough discussion of electromagnetic standards and units. Recommended by many institutions. Electromagnetism. Second Edition has also been adopted by the Open University as the course book for its third level course on electromagnetism.
A multi-band, multi-level, multi-electron model for efficient FDTD simulations of electromagnetic interactions with semiconductor quantum wells
Ravi, Koustuban; Ho, Seng-Tiong
We report a new computational model for simulations of electromagnetic interactions with semiconductor quantum well(s) (SQW) in complex electromagnetic geometries using the finite difference time domain (FDTD) method. The presented model is based on an approach of spanning a large number of electron transverse momentum states in each SQW sub-band (multi-band) with a small number of discrete multi-electron states (multi-level, multi-electron). This enables accurate and efficient two dimensional (2-D) and 3-D simulations of nanophotonic devices with SQW active media. The model includes the following features: (1) Optically induced interband transitions between various SQW conduction and heavy-hole or light-hole sub-bands are considered. (2) Novel intra sub-band and inter sub-band transition terms are derived to thermalize the electron and hole occupational distributions to the correct Fermi-Dirac distributions. (3) The terms in (2) result in an explicit update scheme which circumvents numerically cumbersome ite...
Gravito-electromagnetic resonances
Christos G. Tsagas
The interaction between gravitational and electromagnetic radiation has a rather long research history. It is well known, in particular, that gravity-wave distortions can drive propagating electromagnetic signals. Since forced oscillations provide the natural stage for resonances to occur, gravito-electromagnetic resonances have been investigated as a means of more efficient gravity-wave detection methods. In this report, we consider the coupling between the Weyl and the Maxwell fields on a Minkowski background, which also applies to astrophysical environments where gravity is weak, at the second perturbative level. We use covariant methods that describe gravitational waves via the transverse component of the shear, instead of pure-tensor metric perturbations. The aim is to calculate the properties of the electromagnetic signal, which emerges from the interaction of its linear counterpart with an incoming gravitational wave. Our analysis shows how the wavelength and the amplitude of the gravitationally driven electromagnetic wave vary with the initial conditions. More specifically, for certain initial data, the amplitude of the induced electromagnetic signal is found to diverge. Analogous, diverging, gravito-electromagnetic resonances were also reported in cosmology. Given that, we extend our Minkowski-space study to cosmology and discuss analogies and differences in the physics and in the phenomenology of the Weyl-Maxwell coupling between the aforementioned two physical environments.
Gravito-electromagnetic resonances
Tsagas, Christos G
The interaction between gravitational and electromagnetic radiation has a rather long research history. It is well known, in particular, that gravity-wave distortions can drive propagating electromagnetic signals. Since forced oscillations provide the natural stage for resonances to occur, gravito-electromagnetic resonances have been investigated as a means of more efficient gravity-wave detection methods. In this report, we consider the coupling between the Weyl and the Maxwell fields on a Minkowski background, which also applies to astrophysical environments where gravity is weak, at the second perturbative level. We use covariant methods that describe gravitational waves via the transverse component of the shear, instead of pure-tensor metric perturbations. The aim is to calculate the properties of the electromagnetic signal, which emerges from the interaction of its linear counterpart with an incoming gravitational wave. Our analysis shows how the wavelength and the amplitude of the gravitationally driven...
NSDL National Science Digital Library
David P. Stern
These pages, part of From Stargazers to Starships, explain electromagnetic waves and sunlight. Information inlcudes physiological and spectral color, spectral lines, the electromagnetic field work by Maxwell, the discovery of radio waves by Hertz, and photons and Einsteins relation. Stargazers also has detailed lesson plans accompanying these sections.
ERIC Educational Resources Information Center
Milson, James L.
Three activities involving electromagnetism are presented. Discussed are investigations involving the construction of an electromagnet, the effect of the number of turns of wire in the magnet, and the effect of the number of batteries in the circuit. Extension activities are suggested. (CW)
NSDL National Science Digital Library
Fendt, Walter
This simulation shows a plane polarized electromagnetic wave propagating in positive x direction. The vectors of the electric field (red) are parallel to the y axis, the vectors of the magnetic field (blue) are parallel to the z axis. This applet illustrates the behavior of the fields in electromagnetic waves. This is part of a large collection of physics applets available in several languages.
Optomechanical analog of two-color electromagnetically induced transparency: Photon transmission through an optomechanical device with a two-level system
NASA Astrophysics Data System (ADS)
Wang, Hui; Gu, Xiu; Liu, Yu-xi; Miranowicz, Adam; Nori, Franco
Some optomechanical systems can be transparent to a probe field when a strong driving field is applied. These systems can provide an optomechanical analog of electromagnetically induced transparency (EIT). We study the transmission of a probe field through a hybrid optomechanical system consisting of a cavity and a mechanical resonator with a two-level system (qubit). The qubit might be an intrinsic defect inside the mechanical resonator, a superconducting artificial atom, or another two-level system. The mechanical resonator is coupled to the cavity field via radiation pressure and to the qubit via the Jaynes-Cummings interaction. We find that the dressed two-level system and mechanical phonon can form two sets of three-level systems. Thus, there are two transparency windows in the discussed system. We interpret this effect as an optomechanical analog of two-color EIT (or double EIT). We demonstrate how to switch between one and two EIT windows by changing the transition frequency of the qubit. We show that the absorption and dispersion of the system are mainly affected by the qubit-phonon coupling strength and the transition frequency of the qubit.
Simultaneous electromagnetically induced transparency for two circularly polarized lasers coupled to the same linearly polarized laser in a four-level atomic system in the W scheme
Bahrim, Cristian; Nelson, Chris [Department of Physics, Lamar University, P.O. Box 10046, Beaumont, Texas 77710 (United States)
Electromagnetic induced transparency (EIT) can be produced in a four-level atomic system in the W scheme using a linearly polarized optical field for simultaneously slowing down two {sigma}{sup +} and {sigma}{sup -} circularly polarized optical fields. This four-level atomic system can be set up with a |{sup 1}S{sub 0}> ground state and three Zeeman levels of the |{sup 1}P{sub 1}> excited state of any alkali-metal atom placed in a weak magnetic field. We apply our W scheme to ultracold magnesium atoms for neglecting the collisional dephasing. Atomic coherences are reported after solving a density matrix master equation including radiative relaxations from Zeeman states of the |{sup 1}P{sub 1}> multiplet to the |{sup 1}S{sub 0}> ground state. The EIT feature is analyzed using the transit time between the normal dispersive region and the EIT region. The evolution of the EIT feature with the variation of the coupling field is discussed using an intuitive dressed-state representation. We analyze the sensitivity of an EIT feature to pressure broadening of the excited Zeeman states.
The effect of low level radiofrequency electromagnetic radiation on the excretion rates of stress hormones in operators during 24-hour shifts.
Vangelova, K; Israel, M; Mihaylov, S
The aim of the study was to investigate the effect of long term exposure to low level radiofrequency (RF) electromagnetic (EM) radiation on the excretion rates of stress hormones in satellite station operators during 24-hour shifts. Twelve male operators at a satellite station for TV communications and space research were studied during 24-hour shifts. Dosimetric evaluation of the exposure was carried out and showed low level exposure with specific absorption of 0.1127 J.kg-1. A control group of 12 unexposed male operators with similar job task and the same shift system were studied, too. The 11-oxycorticosteroids (11-OCS), adrenaline and noradrenaline were followed by spectrofluorimetric methods on 3-hour intervals during the 24-hour shifts. The data were analyzed by tests for interindividual analysis, Cosinor analysis and analysis of variance (ANOVA). Significant increase in the 24-hour excretion of 11-OCS and disorders in its circadian rhythm, manifested by increase in the mesor, decrease in the amplitude and shift in the acrophase were found in the exposed operators. The changes in the excretion rates of the catecholamines were significant and showed greater variability of both variables. The long term effect of the exposure to low-level RF EM radiation evoked pronounced stress reaction with changes in the circadian rhythm of 11-OCS and increased variability of catecholamines secretion. The possible health hazards associated with observed alteration in the stress system need to be clarified by identification of their significance and prognostic relevance. PMID:12096679
The Electromagnetic Spectrum: Projecting Visible Spectra
NSDL National Science Digital Library
In this activity, students study the range of colors in a visible light spectrum created from either a glass prism or holographic diffraction grating. This activity is in unit 2 of the "Space-Based Astronomy" guide that contains background information, worksheets, assessment activities, extensions, and alignment to national education standards.
Classical analogs of double electromagnetically induced transparency
NASA Astrophysics Data System (ADS)
Bai, Zhengyang; Hang, Chao; Huang, Guoxiang
Double electromagnetically induced transparency (DEIT) in a four-level atomic system with tripod-type energy-level configuration is modeled by using two classical systems. The first is a set of three coupled harmonic oscillators subject to frictional forces and external drives and the second is a set of three coupled RLC circuits with electric resistors and alternating voltage sources. It is shown that both of the two classical systems have absorption spectra of DEIT similar to that of the four-level tripod-type atomic system. These classical analogies provide simple and intuitive physical description of quantum interference processes and can be used to illustrate experimental observations of the DEIT in quantum systems.
Level 0 to 1 processing of the imaging Fourier transform spectrometer GLORIA: generation of radiometrically and spectrally calibrated spectra
NASA Astrophysics Data System (ADS)
Kleinert, A.; Friedl-Vallon, F.; Guggenmoser, T.; Höpfner, M.; Neubert, T.; Ribalda, R.; Sha, M. K.; Ungermann, J.; Blank, J.; Ebersoldt, A.; Kretschmer, E.; Latzko, T.; Oelhaf, H.; Olschewski, F.; Preusse, P.
The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) is an imaging Fourier transform spectrometer that is capable of operating on various high altitude research aircraft. It measures the atmospheric emission in the thermal infrared spectral region in limb and nadir geometry. GLORIA consists of a classical Michelson interferometer combined with an infrared camera. The infrared detector has a usable range of 128 × 128 pixels, measuring up to 16 384 interferograms simultaneously. Imaging Fourier transform spectrometers impose a number of challenges with respect to instrument calibration and algorithm development. The innovative optical setup with extremely high optical throughput requires the development of new methods and algorithms for spectral and radiometric calibration. Due to the vast amount of data there is a high demand for scientifically intelligent optimisation of the data processing. This paper outlines the characterisation and processing steps required for the generation of radiometrically and spectrally calibrated spectra. Methods for performance optimisation of the processing algorithm are presented. The performance of the data processing and the quality of the calibrated spectra are demonstrated for measurements collected during the first deployments of GLORIA on aircraft.
Level 0 to 1 processing of the imaging Fourier transform spectrometer GLORIA: generation of radiometrically and spectrally calibrated spectra
NASA Astrophysics Data System (ADS)
Kleinert, A.; Friedl-Vallon, F.; Guggenmoser, T.; Höpfner, M.; Neubert, T.; Ribalda, R.; Sha, M. K.; Ungermann, J.; Blank, J.; Ebersoldt, A.; Kretschmer, E.; Latzko, T.; Oelhaf, H.; Olschewski, F.; Preusse, P.
The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) is an imaging Fourier transform spectrometer that is capable of operating on various high-altitude research aircraft. It measures the atmospheric emission in the thermal infrared spectral region in limb and nadir geometry. GLORIA consists of a classical Michelson interferometer combined with an infrared camera. The infrared detector has a usable area of 128 × 128 pixels, measuring up to 16 384 interferograms simultaneously. Imaging Fourier transform spectrometers impose a number of challenges with respect to instrument calibration and algorithm development. The optical setup with extremely high optical throughput requires the development of new methods and algorithms for spectral and radiometric calibration. Due to the vast amount of data there is a high demand for scientifically intelligent optimisation of the data processing. This paper outlines the characterisation and processing steps required for the generation of radiometrically and spectrally calibrated spectra. Methods for performance optimisation of the processing algorithm are presented. The performance of the data processing and the quality of the calibrated spectra are demonstrated for measurements collected during the first deployments of GLORIA on aircraft.
Crane, Randolph W.; Marts, Donna J.
An electromagnetic fastener for manipulating objects in space uses the matic attraction of various metals. An end effector is attached to a robotic manipulating system having an electromagnet such that when current is supplied to the electromagnet, the object is drawn and affixed to the end effector, and when the current is withheld, the object is released. The object to be manipulated includes a multiplicity of ferromagnetic patches at various locations to provide multiple areas for the effector on the manipulator to become affixed to the object. The ferromagnetic patches are sized relative to the object's geometry and mass.
Crane, Randolph W. (Idaho Falls, ID); Marts, Donna J. (Idaho Falls, ID)
An electromagnetic fastener for manipulating objects in space uses the matic attraction of various metals. An end effector is attached to a robotic manipulating system having an electromagnet such that when current is supplied to the electromagnet, the object is drawn and affixed to the end effector, and when the current is withheld, the object is released. The object to be manipulated includes a multiplicity of ferromagnetic patches at various locations to provide multiple areas for the effector on the manipulator to become affixed to the object. The ferromagnetic patches are sized relative to the object's geometry and mass.
... off radio-frequency energy (RF), a form of electromagnetic radiation. Scientists need to do more research on this before they can say for sure. NIH: National Institute of Environmental Health Sciences
Nuclear level densities in {sup 47}V, {sup 48}V, {sup 49}V, {sup 53}Mn, and {sup 54}Mn from neutron evaporation spectra
Zhuravlev, B. V., E-mail: firstname.lastname@example.com; Lychagin, A. A.; Titarenko, N. N.; Demenkov, V. G.; Trykova, V. I. [Institute for Physics and Power Engineering (Russian Federation)
The spectra of neutrons from the (p, n) reactions on {sup 47}Ti, {sup 48}Ti, {sup 49}Ti, {sup 53}Cr, and {sup 54}Cr nuclei were measured in the proton-energy range 7-11 MeV. The measurements were performed with the aid of a fast-neutron spectrometer by the time-of-flight method over the base of the EGP-15 tandem accelerator of the Institute for Physics and Power Engineering (IPPE, Obninsk). Owing to a high resolution and a high stability of the time-of-flight spectrometer used, low-lying discrete levels could be identified reliably along with a continuum section of neutron spectra. An analysis of measured data was performed within the statistical equilibrium and preequilibrium models of nuclear reactions. The relevant calculations were performed by using the exact formalism of Hauser-Feshbach statistical theory supplemented with the generalized model of a superfluid nucleus, the back-shifted Fermi gas model, and the Gilbert-Cameron composite formula for the nuclear level density. The nuclear level densities for {sup 47}V, {sup 48}V, {sup 49}V, {sup 53}Mn, and {sup 54}Mn were determined along with their energy dependences and model parameters. The results are discussed together with available experimental data and recommendations of model systematics.
Nuclear level densities in 208Bi and 209Po from the neutron spectra in the ( p, n) reactions on 208Pb and 209Bi nuclei
NASA Astrophysics Data System (ADS)
Zhuravlev, B. V.; Lychagin, A. A.; Titarenko, N. N.; Demenkov, V. G.; Trykova, V. I.
The spectra of neutrons from the ( p, n) reactions on the 208Pb and 209Bi nuclei were measured in the proton-energy range 8-11 MeV. These measurements were performed by using a time-of-flight spectrometer of fast neutrons on the basis of the pulsed tandem accelerator EGP-15 of the Institute of Physics and Power Engineering (Obninsk, Russian Federation). A high resolution and stability of the time-of-flight spectrometermade it possible to identify reliably low-lying discrete levels alongwith the continuum section of the neutron spectra. The measured data were analyzed on the basis of the statistical equilibrium and preequilibrium models of nuclear reactions. The respective calculations were performed by using the precise formalism of Hauser-Feshbach statistical theory together with the generalizedmodel of a superfluid nucleus and the back-shifted Fermi gas model for the nuclear-level density. The nuclear-level densities in 208Bi and 209Po were determined along with their energy dependences and model parameters. Our results are discussed together with available experimental data and recommendations of model systematics.
Single vibronic level fluorescence spectra from the S 1( 1B 2u) state of p-difluorobenzene vapor
NASA Astrophysics Data System (ADS)
Coveleskie, R. A.; Parmenter, C. S.
1B 2u ? 1A 1g fluorescence spectra have been obtained after pumping each of 19 bands in the S1 ? S0 absorption of p-difluorobenzene under collision-free conditions. The fluorescence analyses provide new assignments of some absorption bands and confirmations of others so that the assignment of the principal structure in absorption is essentially secure. Only the identity of some sequence forming modes remains unconfirmed. The assignments confirm a number of excited-state fundamentals and provide new values for others (Table I). Analysis of the weaker structure in zero-point S1 fluorescence gives a full picture of vibrational activity in the S1 ? S0 transition. In so far as can be determined, the vibrational activities in fluorescence and absorption are in complete correspondence. The vibrational activity in the allowed p-difluorobenzene transition replicates to a good degree that found in the forbidden transition of benzene. Evidence suggesting a nonplanar S1 state is found. A Franck-Condon analysis is given for progressions in three modes, and several strong Fermi resonances are identified in the S1 state.
atomic spectra 1 Atomic Spectra
Glashausser, Charles
Physics, pp. 88-93 (Rutherford nuclear model), 93-106 (atomic structure and electron spectra) 2. D. Watomic spectra 1 Atomic Spectra '96, THK-MRM Object To become familiar with the construction and interpret spin-orbit doublets and triplets in alkali spectra. References 1. Serway, Moses and Moyer: Modern
Comparison of the electronic excitation spectra of chlorophyll a and pheophytin a calculated at density functional theory level
NASA Astrophysics Data System (ADS)
Sundholm, Dage
The molecular structures of chlorophyll a and pheophytin a, with the phytyl group replaced by a hydrogen, have been optimized at the density functional theory (DFT) level. The excitation energies and oscillator strengths obtained at the DFT level using the time-dependent perturbation theory approach are compared to experimental data. In the visible region, 12 electronic transitions are obtained which is in a good agreement with the experimental observations. The present calculations show that Gouterman's generally accepted four-orbital model does not correctly describe the excitation spectrum of chlorophylls.
Electromagnetic Theory 1 /56 Electromagnetic Theory
Bicknell, Geoff
Electromagnetic Theory 1 /56 Electromagnetic Theory Summary: · Maxwell's equations · EM Potentials · Equations of motion of particles in electromagnetic fields · Green's functions · Lienard-Weichert potentials · Spectral distribution of electromagnetic energy from an arbitrarily moving charge #12;Electromagnetic
IUPAC critical evaluation of the rotational-vibrational spectra of water vapor, Part III: Energy levels and transition wavenumbers for H216O
NASA Astrophysics Data System (ADS)
Tennyson, Jonathan; Bernath, Peter F.; Brown, Linda R.; Campargue, Alain; Császár, Attila G.; Daumont, Ludovic; Gamache, Robert R.; Hodges, Joseph T.; Naumenko, Olga V.; Polyansky, Oleg L.; Rothman, Laurence S.; Vandaele, Ann Carine; Zobov, Nikolai F.; Al Derzi, Afaf R.; Fábri, Csaba; Fazliev, Alexander Z.; Furtenbacher, Tibor; Gordon, Iouli E.; Lodi, Lorenzo; Mizus, Irina I.
This is the third of a series of articles reporting critically evaluated rotational-vibrational line positions, transition intensities, and energy levels, with associated critically reviewed labels and uncertainties, for all the main isotopologues of water. This paper presents experimental line positions, experimental-quality energy levels, and validated labels for rotational-vibrational transitions of the most abundant isotopologue of water, H216O. The latest version of the MARVEL (Measured Active Rotational-Vibrational Energy Levels) line-inversion procedure is used to determine the rovibrational energy levels of the electronic ground state of H216O from experimentally measured lines, together with their self-consistent uncertainties, for the spectral region up to the first dissociation limit. The spectroscopic network of H216O containstwo components, an ortho (o) and a para (p) one. For o-H216O and p-H216O, experimentally measured, assigned, and labeled transitions were analyzed from more than 100 sources. The measured lines come from one-photon spectra recorded at room temperature in absorption, from hot samples with temperatures up to 3000 K recorded in emission, and from multiresonance excitation spectra which sample levels up to dissociation. The total number of transitions considered is 184 667 of which 182 156 are validated: 68 027 between para states and 114 129 ortho ones. These transitions give rise to 18 486 validated energy levels, of which 10 446 and 8040 belong to o-H216O and p-H216O, respectively. The energy levels, including their labeling with approximate normal-mode and rigid-rotor quantum numbers, have been checked against ones determined from accurate variational nuclear motion computations employing exact kinetic energy operators as well as against previous compilations of energy levels. The extensive list of MARVEL lines and levels obtained are deposited in the supplementary data of this paper, as well as in a distributed information system applied to water, W@DIS, where they can easily be retrieved.
Evidence for replicate 5p core levels in photoelectron spectra of Eu metal due to nonconstant kinetic-energy resonant Auger decay
Haffner, S. [Department of Physics and Ames Laboratory, U. S. Department of Energy, Iowa State University, Ames, Iowa 50011 (United States)] [Department of Physics and Ames Laboratory, U. S. Department of Energy, Iowa State University, Ames, Iowa 50011 (United States); Olson, C. G. [Department of Physics and Ames Laboratory, U. S. Department of Energy, Iowa State University, Ames, Iowa 50011 (United States)] [Department of Physics and Ames Laboratory, U. S. Department of Energy, Iowa State University, Ames, Iowa 50011 (United States); Lynch, D. W. [Department of Physics and Ames Laboratory, U. S. Department of Energy, Iowa State University, Ames, Iowa 50011 (United States)] [Department of Physics and Ames Laboratory, U. S. Department of Energy, Iowa State University, Ames, Iowa 50011 (United States)
Satellites on the low-binding-energy side of core-level photoelectron emission due to extra 4f screening are a well-known feature in the x-ray photoelectron spectra of valence fluctuation materials and rare-earth metals. A notable exception is Eu metal, where up to now no low-binding-energy satellite has been observed. In this paper we show that in Eu metal the 4d-4f resonance can decay via a resonant Auger decay, which is not a constant kinetic-energy feature due to a rapid change of the strength of 4f screening with excitation energy, establishing a low-binding-energy replica of the 5p core-level photoelectron emission. (c) 1999 The American Physical Society.
Simulation of the temperature elevation in children exposed to plane wave electromagnetic fields (10 MHz-1 GHz) at the ICNIRP reference level.
Niedermayr, Florian; Leitgeb, Norbert; Siegl, Werner
Because of a lack of thermal models, to date, limitation of exposure to an electromagnetic field (EMF) has been based on restricting intracorporal specific absorption rates. To allow convenient compliance checks, reference field values have been defined. If they are met, compliance with basic restrictions is assumed. This article demonstrates that this assumption is not valid in every case. It has therefore been investigated as to whether the biological goal of limiting tissue heating is still met, in particular with regard to children. The thermal solver applied is based on the bioheat equation, with implemented additional improvements that allow consideration of blood flow and metabolic rate as a function of local tissue temperature rise and, in addition, adapt the blood temperature relative to the absorbed power. As a further improvement, heat exchange at the tissue/air boundary has been modeled, with radiation, convection, and sweating considered as well. The mathematical equations describing these additional thermoregulatory mechanisms were taken from the literature and unified in the thermoregulatory model used for this study. For the investigated case of plane wave exposure, the results confirm the violation of the basic restrictions in five of the six models when exposed to reference EMF levels. However, using thermal modeling, it was possible to demonstrate that heating remained within the biological tolerances. In particular, temperature elevation of the body core temperature remained <0.014°C and the local peak temperature did not exceed 1°C. PMID:22691427
Milton, Graeme W
The electromagnetic analog of an elastic spring-mass network is constructed. These are called electromagnetic circuits and linear electrical circuits correspond to a subclass of them. They consist of thin triangular magnetic components joined at the edges by cylindrical dielectric components. Some of the edges can be terminal edges to which electric fields are applied. The response is measured in terms of the free currents associated with the terminal edges. The relation between the terminal electric fields and the terminal free currents is governed by a symmetric complex matrix W. In the case where all the terminal edges are disjoint, and the frequency is fixed, a complete characterization is obtained of all possible response matrices W, both in the lossless and lossy cases. There are also dual electromagnetic circuits consisting of thin triangular dielectric components joined at the edges by cylindrical magnetic components
M. Novello; F. T. Falciano; E. Goulart
We show that Maxwell's electromagnetism can be mapped into the Born-Infeld theory in a curved space-time, which depends only on the electromagnetic field in a specific way. This map is valid for any value of the two lorentz invariants $F$ and $G$ confirming that we have included all possible solutions of Maxwell's equations. Our result seems to show that specifying the dynamics and the space-time structure of a given theory can be viewed merely as a choice of representation to describe the physical system.
NSDL National Science Digital Library
Orzali, Joe
This hands-on classroom activity will help students understand the connections between magnets and electricity generation. The learning cycle planner includes an exploration phase with a hands-on activity and a suggested video. The concept development phase suggests showing the film "Who Killed the Electric Car?" The main part of this learning unit is the electromagnet lesson, which is a two day small group activity in which students will create an electromagnet. This document may be downloaded in PDF file format; student worksheets are included.
Deriving electromagnetic radial diffusion coefficients of radiation belt equatorial particles for different levels of magnetic activity based on magnetic field measurements at geostationary orbit
NASA Astrophysics Data System (ADS)
Lejosne, SolčNe; Boscher, Daniel; Maget, Vincent; Rolland, Guy
In this paper, we show that the correlation that exists between magnetic variations and induced electric fields through Faraday's law is of prime importance for adequately characterizing electromagnetic radial diffusion. Accordingly, we present an approach to derive electromagnetic radial diffusion coefficients based on magnetic field measurements at geostationary orbit. It consists of setting a very simple theoretical electromagnetic field model, considering the magnetic field as a background dipolar field on which two small time disturbances are superimposed: a symmetric disturbance and an asymmetric disturbance. Within this framework, electromagnetic radial diffusion is quantified analytically, taking into account both induced electric and magnetic contributions. The role played by the time variations of the field asymmetry is highlighted. From this, we deduce instantaneous field asymmetries from measurements of the magnetic field at the same time in two different places of the geostationary orbit. Then, we perform a statistical analysis of the time variations of this signal based on more than 7 years of data from the NOAA-GOES 8, NOAA-GOES 10, and NOAA-GOES 12 spacecraft, working with time resolutions of 1 and 5 min. We show that the asymmetry signal is not stationary, having time-dependent statistical properties, and we question accordingly the standard formulation of the electromagnetic radial diffusion coefficient and the role of drift-resonant interactions. Finally, we provide new electromagnetic radial diffusion coefficients at geostationary orbit as a function of electron kinetic energy and Kp index from 0 to 4.
A USGS hydrologist conducts a near-surface electromagnetic induction survey to characterize the shallow earth. The survey was conducted as part of an applied research effort by the USGS Office of Groundwater Branch of Geophysics at Camp Rell, Connecticut, in 2008....
USGS hydrologist conducts a broadband electromagnetic survey in New Orleans, Louisiana. The survey was one of several geophysical methods used during USGS applied research on the utility of the multi-channel analysis of surface waves (MASW) seismic method for non-invasive assessment of earthen levee...
The influence of oxygen adsorption on the NEXAFS and core-level XPS spectra of the C60 derivative PCBM
NASA Astrophysics Data System (ADS)
Brumboiu, Iulia Emilia; Ericsson, Leif; Hansson, Rickard; Moons, Ellen; Eriksson, Olle; Brena, Barbara
Fullerenes have been a main focus of scientific research since their discovery due to the interesting possible applications in various fields like organic photovoltaics (OPVs). In particular, the derivative [6,6]-phenyl-C60-butyric acid methyl ester (PCBM) is currently one of the most popular choices due to its higher solubility in organic solvents compared to unsubstituted C60. One of the central issues in the field of OPVs is device stability, since modules undergo deterioration (losses in efficiency, open circuit voltage, and short circuit current) during operation. In the case of fullerenes, several possibilities have been proposed, including dimerization, oxidation, and impurity related deterioration. We have studied by means of density functional theory the possibility of oxygen adsorption on the C60 molecular moiety of PCBM. The aim is to provide guidelines for near edge X-ray absorption fine structure (NEXAFS) and X-ray photoelectron spectroscopy (XPS) measurements which can probe the presence of atomic or molecular oxygen on the fullerene cage. By analysing several configurations of PCBM with one or more adsorbed oxygen atoms, we show that a joint core level XPS and O1s NEXAFS investigation could be effectively used not only to confirm oxygen adsorption but also to pinpoint the bonding configuration and the nature of the adsorbate.
Personal radiofrequency electromagnetic field measurements in The Netherlands: exposure level and variability for everyday activities, times of day and types of area.
Bolte, John F B; Eikelboom, Tessa
Knowledge of the exposure to radiofrequency electromagnetic fields is necessary for epidemiological studies on possible health effects. The main goal of this study is to determine the exposure level and spatial and temporal variances during 39 everyday activities in 12 frequency bands used in mobile telecommunication and broadcasting. Therefore, 24 h measurements were gathered from 98 volunteers living in or near Amsterdam and Purmerend, The Netherlands. They carried an activity diary to be kept to the minute, a GPS logger sampling at an interval of 1 s, and an EME Spy exposimeter with a detection limit of 0.0066 mW/m(2) sampling at an interval of 10s in 12 frequency bands. The mean exposure over 24 h, excluding own mobile phone use, was 0.180 mW/m(2). During daytime exposure was about the same, but during night it was about half, and in the evening it was about twice as high. The main contribution to environmental exposure (calling by participant not included) is from calling with mobile phones (37.5%), from cordless DECT phones and their docking stations (31.7%), and from the base stations (12.7%). The exposure to mobile phone base stations increases with the percentage of urban ground use, which is an indication for high people density. In agreement, the highest mean exposure relates to the activities with high people density, such as travelling by public transport, visiting social events, pubs or shopping malls. Exposure at home depends mainly on exposure from people calling in the neighbourhood of the participant and thus on the number of persons in a household. In addition just the possession of DECT docking stations leads to exposure as most models transmit continuously in stand-by. Also wireless internet routers continuously transmit in the WiFi band. Though the highest exposure peaks in the WiFi band, up to 0.265 W/m(2), come from stray radiation of microwave ovens. The mean total exposure largely depends on phone calls of a high exposure level and short duration. These calls lead to potentially high contrasts as well in exposure levels between sessions of the same activity as between persons, thus posing a challenge for personal exposure prediction. PMID:22906414
Nuclear Level Densities of 56Co, 57Co, 90Nb, and 94Nb from Neutron Evaporation Spectra in the (p,n) Reaction
NASA Astrophysics Data System (ADS)
Zhuravlev, Boris V.; Kornilov, Nikolai V.; Lychagin, Anatoliy A.; Titarenko, Nikolai N.; Trykova, Valentina I.
Excitation functions, neutron spectra, and angular distributions in the (p,n) reaction on isotopes of 56Fe, 57Fe, 90Zr, and 94Zr have been measured in the proton energy range of (7-11) MeV. The measurements were performed on the pulsed tandem accelerator EGP-15 of IPPE by time-of-flight fast neutron spectrometer. Analyses of the measured data have been carried out in the framework of statistical equilibrium and pre-equilibrium models of nuclear reactions. The contribution of non-equilibrium emission has been studied. The nuclear level densities of 56Co, 57Co 90Nb, 94Nb, and their energy dependences have been determined.
Nuclear Level Densities of 56Co, 57Co, 90Nb, and 94Nb from Neutron Evaporation Spectra in the (p,n) Reaction
Zhuravlev, Boris V.; Kornilov, Nikolai V.; Lychagin, Anatoliy A.; Titarenko, Nikolai N.; Trykova, Valentina I. [Institute for Physics and Power Engineering, 249033 Obninsk, Kaluga Region (Russian Federation)
Excitation functions, neutron spectra, and angular distributions in the (p,n) reaction on isotopes of 56Fe, 57Fe, 90Zr, and 94Zr have been measured in the proton energy range of (7-11) MeV. The measurements were performed on the pulsed tandem accelerator EGP-15 of IPPE by time-of-flight fast neutron spectrometer. Analyses of the measured data have been carried out in the framework of statistical equilibrium and pre-equilibrium models of nuclear reactions. The contribution of non-equilibrium emission has been studied. The nuclear level densities of 56Co, 57Co 90Nb, 94Nb, and their energy dependences have been determined.
Strong permanent magnet-assisted electromagnetic undulator
Halbach, Klaus (Berkeley, CA)
This invention discloses an improved undulator comprising a plurality of electromagnet poles located along opposite sides of a particle beam axis with alternate north and south poles on each side of the beam to cause the beam to wiggle or undulate as it travels generally along the beam axis and permanent magnets spaced adjacent the electromagnetic poles on each side of the axis of said particle beam in an orientation sufficient to reduce the saturation of the electromagnet poles whereby the field strength of the electromagnet poles can be increased beyond the normal saturation levels of the electromagnetic poles.
C. Furse
The focus of this issue's column is teaching electromagnetic compatibility. A summary of resources for this topic is found in the article by Levent Sevgi, and additional online course materials are summarized on the IEEE AP-S education course material repository Web site: www.ece.utah.edu\\/?cfurse\\/APS\\/course.htm. The column also provides a set of suggestions that are applicable to a variety of courses on
Aldridge, David F.
A reciprocity theorem is an explicit mathematical relationship between two different wavefields that can exist within the same space - time configuration. Reciprocity theorems provi de the theoretical underpinning for mod ern full waveform inversion solutions, and also suggest practical strategies for speed ing up large - scale numerical modeling of geophysical datasets . In the present work, several previously - developed electromagnetic r eciprocity theorems are generalized to accommodate a broader range of medi um, source , and receiver types. Reciprocity relations enabling the interchange of various types of point sources and point receivers within a three - dimensional electromagnetic model are derived. Two numerical modeling algorithms in current use are successfully tested for adherence to reciprocity. Finally, the reciprocity theorem forms the point of departure for a lengthy derivation of electromagnetic Frechet derivatives. These mathe matical objects quantify the sensitivity of geophysical electromagnetic data to variatio ns in medium parameters, and thus constitute indispensable tools for solution of the full waveform inverse problem. ACKNOWLEDGEMENTS Sandia National Labor atories is a multi - program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the US Department of Energy's National Nuclear Security Administration under contract DE - AC04 - 94AL85000. Signif icant portions of the work reported herein were conducted under a Cooperative Research and Development Agreement (CRADA) between Sandia National Laboratories (SNL) and CARBO Ceramics Incorporated. The author acknowledges Mr. Chad Cannan and Mr. Terry Pa lisch of CARBO Ceramics, and Ms. Amy Halloran, manager of SNL's Geophysics and Atmospheric Sciences Department, for their interest in and encouragement of this work. Special thanks are due to Dr . Lewis C. Bartel ( recently retired from Sandia National Labo ratories and now a geophysical consultant ) and Dr. Chester J. Weiss (recently rejoined with Sandia National Laboratories) for many stimulating (and reciprocal!) discussions regar ding the topic at hand.
NSDL National Science Digital Library
Part of the larger Imagine the Universe educational site, the Electromagnetic Spectrum site is another great resource from NASA. The site gives clear and easy-to-understand explanations, while providing keywords throughout the page that are linked to a dictionary of terms for easy access to further information. Students will enjoy the colorful illustrations accompanying the text, which vertically follow the spectrum from radio to gamma rays, while teachers will appreciate the related lesson plans link that will help reinforce the learning.
Dipole-induced electromagnetic transparency.
Puthumpally-Joseph, Raiju; Sukharev, Maxim; Atabek, Osman; Charron, Eric
We determine the optical response of a thin and dense layer of interacting quantum emitters. We show that, in such a dense system, the Lorentz redshift and the associated interaction broadening can be used to control the transmission and reflection spectra. In the presence of overlapping resonances, a dipole-induced electromagnetic transparency (DIET) regime, similar to electromagnetically induced transparency (EIT), may be achieved. DIET relies on destructive interference between the electromagnetic waves emitted by quantum emitters. Carefully tuning material parameters allows us to achieve narrow transmission windows in, otherwise, completely opaque media. We analyze in detail this coherent and collective effect using a generalized Lorentz model and show how it can be controlled. Several potential applications of the phenomenon, such as slow light, are proposed. PMID:25361258
Dipole-Induced Electromagnetic Transparency
NASA Astrophysics Data System (ADS)
Puthumpally-Joseph, Raiju; Sukharev, Maxim; Atabek, Osman; Charron, Eric
We determine the optical response of a thin and dense layer of interacting quantum emitters. We show that, in such a dense system, the Lorentz redshift and the associated interaction broadening can be used to control the transmission and reflection spectra. In the presence of overlapping resonances, a dipole-induced electromagnetic transparency (DIET) regime, similar to electromagnetically induced transparency (EIT), may be achieved. DIET relies on destructive interference between the electromagnetic waves emitted by quantum emitters. Carefully tuning material parameters allows us to achieve narrow transmission windows in, otherwise, completely opaque media. We analyze in detail this coherent and collective effect using a generalized Lorentz model and show how it can be controlled. Several potential applications of the phenomenon, such as slow light, are proposed.
Out-of-plane (e,2e) angular distributions and energy spectra of helium L = 0,1,2 autoionizing levels
Harak, B. A. de [Physics Department, Illinois Wesleyan University, P.O. Box 2900, Bloomington, Illinois 61702-2900 (United States); Bartschat, K. [Department of Physics and Astronomy, Drake University, Des Moines, Iowa 50311 (United States); Martin, N. L. S. [Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506-0055 (United States)
Angular distribution and spectral (e,2e) measurements are reported for the helium autoionizing levels (2s{sup 2}){sup 1}S, (2p{sup 2}){sup 1}D, and (2s2p){sup 1}P. A special out-of-plane geometry is used where the ejected electrons are emitted in a plane perpendicular to the scattered electron direction. The kinematics are chosen so that this plane contains the momentum-transfer direction. While the recoil peak almost vanishes in the angular distribution for direct ionization, it remains significant for the autoionizing levels and exhibits a characteristic shape for each orbital angular momentum L=0,1,2. A second-order model in the projectile-target interaction correctly reproduces the observed magnitudes of the recoil peaks, but is a factor of 2 too large in the central out-of-plane region. Observed (e,2e) energy spectra for the three resonances over the full angular range are well reproduced by the second-order calculation. Calculations using a first-order model fail to reproduce both the magnitudes of the recoil peaks and the spectral line profiles.
Analytical method of spectra calculations in the Bargmann representation
Andrzej J. Maciejewski; Maria Przybylska; Tomasz Stachowiak
We formulate a universal method for solving an arbitrary quantum system which, in the Bargmann representation, is described by a system of linear equations with one independent variable, such as one- and multi-photon Rabi models, or $N$ level systems interacting with a single mode of the electromagnetic field and their various generalizations. We explain three types of conditions that determine the spectrum and show their usage for two deformations of the Rabi model. We prove that the spectra of both models are just zeros of transcendental functions, which in one case are given explicitly in terms of confluent Heun functions.
Electromagnetic radiation generated by arcing in low density plasma
NASA Technical Reports Server (NTRS)
Vayner, Boris V.; Ferguson, Dale C.; Snyder, David B.; Doreswamy, C. V.
An unavoidable step in the process of space exploration is to use high-power, very large spacecraft launched into Earth orbit. Obviously, the spacecraft will need powerful energy sources. Previous experience has shown that electrical discharges occur on the surfaces of a high-voltage array, and these discharges (arcs) are undesirable in many respects. Moreover, any high voltage conductor will interact with the surrounding plasma, and that interaction may result in electrical discharges between the conductor and plasma (or between two conductors with different potentials, for example, during docking and extravehicular activity). One very important aspect is the generation of electromagnetic radiation by arcing. To prevent the negative influence of electromagnetic noise on the operation of spacecraft systems, it seems necessary to determine the spectra and absolute levels of the radiation, and to determine limitations on the solar array bias voltage that depend on the parameters of LEO plasma and the technical requirements of the spacecraft equipment. This report describes the results of an experimental study and computer simulation of the electromagnetic radiation generated by arcing on spacecraft surfaces. A large set of high quality data was obtained during the Solar Array Module Plasma Interaction Experiment (SAMPIE, flight STS-62) and ground test. These data include the amplitudes of current, pulse forms, duration of each arc, and spectra of plasma waves. A theoretical explanation of the observed features is presented in this report too. The elaborated model allows us to determine the parameters of the electromagnetic noise for different frequency ranges, distances from the arcing site, and distinct kinds of plasma waves.
Electromagnetic microactuators
NASA Astrophysics Data System (ADS)
Büttgenbach, S.; Al-Halhouli, A. T.; Feldmann, M.; Seidemann, V.; Waldschik, A.
High precision microactuators have become key elements for many applications of MEMS, for example for positioning and handling systems as well as for microfluidic devices. Electromagnetic microactuators exhibit considerable benefits such as high forces, large deflections, low input impedances and thus, the involvement of only low voltages. Most of the magnetic microactuators developed so far are based on the variable reluctance principle and use soft magnetic materials. Since the driving force of such actuators is proportional to their volume, they require structures with rather great heights and aspect ratios. Therefore, the development of new photo resists, which allow UV exposure of thick layers of resist, has been essential for the advancement of variable reluctance microactuators. On the other hand, hard magnetic materials have the potential for larger forces and larger deflections. Accordingly, polymer magnets, in which micro particles of hard magnetic material are suspended in a polymer matrix, have been used to fabricate permanent magnet microactuators. In this paper we give an overview of sophisticated electromagnetic microactuators which have been developed in our laboratory in the framework of the Collaborative Research Center "Design and Manufacturing of Active Microsystems". In particular, concept, fabrication and test of variable reluctance micro stepper motors, of permanent magnet synchronous micromotors and of microactuators based on the Lorentz force principle will be described. Special emphasis will be given to applications in lab-on-chip systems.
Transient electromagnetic interference in substations
C. M. Wiggins; D. E. Thomas; F. S. Nickel; T. M. Salas; S. E. Wright
Electromagnetic interference levels on sensitive electronic equipment are quantified experimentally and theoretically in air and gas insulated substations of different voltages. Measurement techniques for recording interference voltages and currents and electric and magnetic fields are reviewed and actual interference data are summarized. Conducted and radiated interference coupling mechanisms and levels in substation control wiring are described using both measurement results
ECE 203 Spring 2012 Engineering Electromagnetics Waves (3)
Gilchrist, James F.
ECE 203 Â Spring 2012 Engineering Electromagnetics Waves (3) Lecture Time: Spring 2012, Monday, and A. S. Inan, Electromagnetic Waves, Prentice Hall (2000). Useful EM textbook for ECE 203-level. 2. D. Morgenthaler, J. A. Kong, Electromagnetic Waves, Prentice Hall (1994). Useful textbook for ECE 203-level
Effects of whole body exposure to extremely low frequency electromagnetic fields (ELF-EMF) on serum and liver lipid levels, in the rat
Patricia V Torres-Duran; Aldo Ferreira-Hermosillo; Marco A Juarez-Oropeza; David Elias-Vińas; Leticia Verdugo-Diaz
BACKGOUND: The effects of extremely low-frequency electromagnetic fields (ELF-EMF) on the blood serum and liver lipid concentrations of male Wistar rats were assessed. METHODS: Animals were exposed to a single stimulation (2 h) of ELF-EMF (60 Hz, 2.4 mT) or sham-stimulated and thereafter sacrificed at different times (24, 48 or 96 h after beginning the exposure). RESULTS: Blood lipids showed,
Spontaneous emission of a two-level static atom coupling with the electromagnetic vacuum fluctuations outside a high-dimensional Einstein Gauss-Bonnet black hole
Ming Zhang; Zhan-Ying Yang; Rui-Hong Yue
In present paper, by using the generalized DDC formalism, we investigate the spontaneous excitation of an static atom interacting with electromagnetic vacuum fluctuations outside a EGB black hole in $d$-dimensions. We find that spontaneous excitation does not occur in Boulware vacuum. The Gauss-Bonnet term has no effect on the stability of the atom. Finally, we discuss the contribution of the coupling constant and dimensional factor to the results in three different kinds of spacetime.
Evaluation of the maximum permissible level of low-intensity electromagnetic radiation at mobile connection frequency (1 GHz) by changes in motor activity of Spirostomum Ambiguum.
Sarapultseva, E I; Igolkina, J V; Litovchenko, A V
Electromagnetic radiation at the mobile connection frequency (1 GHz) at maximum energy flow density (10 microW/cm(2)) permitted in Russia causes serious functional disorders in the studied unicellular hydrobionts infusoria Spirostomum ambiguum: reduction of their spontaneous motor activity. The form of biological reaction is uncommon: the effect is threshold, overall, and does not depend on the duration of microwave exposure. PMID:19704941
Evaluation of the Maximum Permissible Level of Low-Intensity Electromagnetic Radiation at Mobile Connection Frequency (1 GHz) by Changes in Motor Activity of Spirostomum Ambiguum
E. I. Sarapultseva; J. V. Igolkina; A. V. Litovchenko
Electromagnetic radiation at the mobile connection frequency (1 GHz) at maximum energy flow density (10 ?W\\/cm2) permitted in Russia causes serious functional disorders in the studied unicellular hydrobionts infusoria Spirostomum ambiguum: reduction of their spontaneous motor activity. The form of biological reaction is uncommon: the effect is threshold, overall,\\u000a and does not depend on the duration of microwave exposure.
Electromagnetic topology: Characterization of internal electromagnetic coupling
NASA Technical Reports Server (NTRS)
Parmantier, J. P.; Aparicio, J. P.; Faure, F.
The main principles are presented of a method dealing with the resolution of electromagnetic internal problems: Electromagnetic Topology. A very interesting way is to generalize the multiconductor transmission line network theory to the basic equation of the Electromagnetic Topology: the BLT equation. This generalization is illustrated by the treatment of an aperture as a four port junction. Analytical and experimental derivations of the scattering parameters are presented. These concepts are used to study the electromagnetic coupling in a scale model of an aircraft, and can be seen as a convenient means to test internal electromagnetic interference.
Hart, Gus
Electromagnetic Field Theory BO THID� UPSILON BOOKS #12;#12;ELECTROMAGNETIC FIELD THEORY #12;#12;Electromagnetic Field Theory BO THID� Swedish Institute of Space Physics and Department of Astronomy and Space, Sweden UPSILON BOOKS · COMMUNA AB · UPPSALA · SWEDEN #12;Also available ELECTROMAGNETIC FIELD THEORY
R. K. Matthews; S. A. Stepanek
Electromagnetic wave testing, which represents a relatively new test technique that involves the union of several disciplines (aerothermodynamics, electromagnetics, materials\\/structures, and advanced diagnostics) is introduced. The essence of this new technique deals with the transmission and possible distortion of electromagnetic waves (RF or IR) as they pass through the bow shock, flow field, and electromagnetic window of a missile flying
Correlation Electromagnetic Analysis for Cryptographic Device
Guo Liang Ding; Jie Chu; Liang Yuan; Qiang Zhao
The article analyzes the CMOS logical gate's electric current characteristic under the active status, establishes the electromagnetic information leakage hamming distance model in registers level. Aimed at the data encryption standard (DES) cryptographic system realized by the P89C668 microcomputer, Correlation Electromagnetic Analysis (CEMA) algorithm was described, the choosing of attack point D and the computational method were analyzed, an attack
Strong permanent magnet-assisted electromagnetic undulator
Halbach, K.
This patent describes an undulator wherein electromagnet poles are located along opposite sides of a particle beam axis normal to the beam axis with alternate north and south poles on each side of the beam to cause the beam to wiggle or undulate as it travels generally along the beam axis, the improvement which comprises reducing the saturation of the electromagnet poles by the use of permanent magnets spaced in between adjacent electromagnetic poles on each side of the axis of the particle beam in an orientation wherein the north and south poles of the permanent magnets are parallel to the particle beam axis and normal to the magnetic axes of the electromagnetic poles to reduce the saturation of the electromagnets to thereby permit the increasing of the field strength of the electromagnets beyond normal saturation levels.
NASA Astrophysics Data System (ADS)
Kolm, H.; Mongeau, P.; Williams, F.
Recent advances in energy storage, switching and magnet technology make electromagnetic acceleration a viable alternative to chemical propulsion for certain tasks, and a means to perform other tasks not previously feasible. Applications include the acceleration of gram-size particles for hypervelocity research and the initiation of fusion by impact, a replacement for chemically propelled artillery, the transportation of cargo and personnel over inaccessible terrain, and the launching of space vehicles to supply massive space operations, and for the disposal of nuclear waste. The simplest launcher of interest is the railgun, in which a short-circuit slide or an arc is driven along two rails by direct current. The most sophisticated studied thus far is the mass driver, in which a superconducting shuttle bucket is accelerated by a line of pulse coils energized by capacitors at energy conversion efficiencies better than 90%. Other accelerators of interest include helical, brush-commutated motors, discrete coil arc commutated drivers, flux compression momentum transformers, and various hybrid electrochemical devices.
Experimental investigation of the ionospheric hysteresis effect on the threshold excitation level of the Stimulated Electromagnetic Emission (SEE) during heating at the second electron gyro-harmonic frequency
NASA Astrophysics Data System (ADS)
Samimi, A.; Scales, W.; Cruz, M.; Isham, B.; Bernhardt, P. A.
Recent experimental observations of the stimulated electromagnetic emission (SEE) spectrum during heating at the second electron gyro-harmonic show structures ordered by ion gyro-frequency. The proposed generation mechanism considers parametric decay of a pump upper hybrid/electron Bernstein (UH/EB) wave into another UH/EB and a group of neutralized ion Bernstein waves. The presumption of the proposed mechanism is that the pump electromagnetic wave is converted into the UH/EB wave. This conversion process generates field aligned irregularity which exhibits hysteresis effect. The predicted ionospheric hysteresis effect is studied during the PARS 2012 at HAARP. The preliminary results are presented for the first time. Also, experimental study of the effects of 1) the transmitter beam angle and 2) the transmitter frequency offset relative to the second electron gyro-harmonic frequency on the ion gyro-harmonic structures in the SEE spectrum are provided. The aforementioned observations are compared to the predictions of the analytical model. Possible connection of the SEE spectral features and artificially generated ionospheric descending layer is also discussed
NSDL National Science Digital Library
Nave, Carl R.
This page from Hyperphysics contains images depicting the light emitted by several elements and their respective spectra. The page also provides a description of how the size of a holographic image scales with the wavelength of the light used to observe it.
Preliminary Spectroscopic Measurements for a Gallium Electromagnetic (GEM) Thruster
NASA Technical Reports Server (NTRS)
Thomas, Robert E.; Burton, Rodney L.; Glumac, Nick G.; Polzin, Kurt A.
As a propellant option for electromagnetic thrusters, liquid ,gallium appears to have several advantages relative to other propellants. The merits of using gallium in an electromagnetic thruster (EMT) are discussed and estimates of discharge current levels and mass flow rates yielding efficient operation are given. The gallium atomic weight of 70 predicts high efficiency in the 1500-2000 s specific impulse range, making it ideal for higher-thrust, near-Earth missions. A spatially and temporally broad spectroscopic survey in the 220-520 nm range is used to determine which species are present in the plasma and estimate electron temperature. The spectra show that neutral, singly, and doubly ionized gallium species are present in a 20 J, 1.8 kA (peak) are discharge. With graphite present on the insulator to facilitate breakdown, singly and doubly ionized carbon atoms are also present, and emission is observed from molecular carbon (CZ) radicals. A determination of the electron temperature was attempted using relative emission line data, and while the spatially and temporally averaged, spectra don't fit well to single temperatures, the data and presence of doubly ionized gallium are consistent with distributions in the 1-3 eV range.
National Institute of Standards and Technology Data Gateway
SRD 78 NIST Atomic Spectra Database (ASD) (Web, free access) This database provides access and search capability for NIST critically evaluated data on atomic energy levels, wavelengths, and transition probabilities that are reasonably up-to-date. The NIST Atomic Spectroscopy Data Center has carried out these critical compilations.
Action of an electromagnetic pulse on a plasma with a high level of ion-acoustic turbulence. Field diffusion and subdiffusion
Ovchinnikov, K. N.; Uryupin, S. A., E-mail: email@example.com [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)
Specific features of the interaction of a relatively weak electromagnetic pulse with a nonisothermal current-carrying plasma in which the electron drift velocity is much higher than the ion-acoustic velocity, but lower than the electron thermal velocity, are studied. If the state of the plasma with ion-acoustic turbulence does not change during the pulse action, the field penetrates into the plasma in the ordinary diffusion regime, but the diffusion coefficient in this case is inversely proportional to the anomalous conductivity. If, during the pulse action, the particle temperatures and the current-driving field change due to turbulent heating, the field penetrates into the plasma in the subdiffusion regime. It is shown how the presence of subdiffusion can be detected by measuring the reflected field.
7. Electromagnetic relations 1 7. ELECTROMAGNETIC RELATIONS
7. Electromagnetic relations 1 7. ELECTROMAGNETIC RELATIONS Revised September 2005 by H.G. Spieler = 10-7 N A-2 ; c = 1 0 0 = 2.997 924 58 Ă? 108 m s-1 #12;2 7. Electromagnetic relations 7.1. Impedances of self-inductance L: Z = jL . Impedance of capacitance C: Z = 1/jC . Impedance of free space: Z = 0/ 0
Electromagnetic propulsion for spacecraft
NASA Technical Reports Server (NTRS)
Myers, Roger M.
Three electromagnetic propulsion technologies, solid propellant pulsed plasma thrusters (PPT), magnetoplasmadynamic (MPD) thrusters, and pulsed inductive thrusters (PIT), were developed for application to auxiliary and primary spacecraft propulsion. Both the PPT and MPD thrusters were flown in space, though only PPT's were used on operational satellites. The performance of operational PPT's is quite poor, providing only approximately 8 percent efficiency at approximately 1000 s specific impulse. However, laboratory PPT's yielding 34 percent efficiency at 2000 s specific impulse were extensively tested, and peak performance levels of 53 percent efficiency at 5170 s specific impulse were demonstrated. MPD thrusters were flown as experiments on the Japanese MS-T4 spacecraft and the Space Shuttle and were qualified for a flight in 1994. The flight MPD thrusters were pulsed, with a peak performance of 22 percent efficiency at 2500 s specific impulse using ammonia propellant. Laboratory MPD thrusters were demonstrated with up to 70 percent efficiency and 700 s specific impulse using lithium propellant. While the PIT thruster has never been flown, recent performance measurements using ammonia and hydrazine propellants are extremely encouraging, reaching 50 percent efficiency for specific impulses between 4000 to 8000 s. The fundamental operating principles, performance measurements, and system level design for the three types of electromagnetic thrusters are reviewed, and available data on flight tests are discussed for the PPT and MPD thrusters.
Secondary electron energy spectra and current density levels emitted from rf biased plasma electrodes in He, Ar, H2, and N2 feedstock gases
NASA Astrophysics Data System (ADS)
Shaw, D. M.; Watanabe, M.; Uchiyama, H.; Collins, G. J.
Ion-induced secondary electron energy spectra I(E) are studied both experimentally and theoretically. The results are based on a radio frequency (rf) biased (13.56 MHz) electrically insulating (Al2O3) plasma electrode surface immersed in a separately powered inductively coupled plasma. Electrode rf bias voltages of 140, 285 and 425 V (peak to ground) are employed and the emitted I(E) spectra are measured 14 cm from the rf biased electrode using a differentially pumped retarding potential analyzer. Plasma feedstock gases employed are H2, N2, Ar, and He in the pressure range of 1 to 20 mTorr. Although generally ignored in the literature, the total measured secondary electron current density je in a 10 mTorr Ar ICP with plasma electron density ne = 1012 cm-3 is je = 2 mA / cm2, which is comparable to the ion current density from the ICP. Such I(E) spectra may play roles in rf discharge mode changes and other phenomena. A crude collisionless rf Child-Langmuir sheath model is used to explain the experimentally measured electron energy spectra.
Skyglow effects in UV and visible spectra: Radiative fluxes
NASA Astrophysics Data System (ADS)
Kocifaj, Miroslav; Solano Lamphar, Hector Antonio
Several studies have tried to understand the mechanisms and effects of radiative transfer under different night-sky conditions. However, most of these studies are limited to the various effects of visible spectra. Nevertheless, the invisible parts of the electromagnetic spectrum can pose a more profound threat to nature. One visible threat is from what is popularly termed skyglow. Such skyglow is caused by injudiciously situated or designed artificial night lighting systems which degrade desired sky viewing. Therefore, since lamp emissions are not limited to visible electromagnetic spectra, it is necessary to consider the complete spectrum of such lamps in order to understand the physical behaviour of diffuse radiation at terrain level. In this paper, the downward diffuse radiative flux is computed in a two-stream approximation and obtained ultraviolet spectral radiative fluxes are inter-related with luminous fluxes. Such a method then permits an estimate of ultraviolet radiation if the traditionally measured illuminance on a horizontal plane is available. The utility of such a comparison of two spectral bands is shown, using the different lamp types employed in street lighting. The data demonstrate that it is insufficient to specify lamp type and its visible flux production independently of each other. Also the UV emissions have to be treated by modellers and environmental scientists because some light sources can be fairly important pollutants in the near ultraviolet. Such light sources can affect both the living organisms and ambient environment.
Gallium Electromagnetic (GEM) Thruster Performance Measurements
NASA Technical Reports Server (NTRS)
Thomas, Robert E.; Burton, Rodney L.; Polzin, K. A.
Discharge current, terminal voltage, and mass bit measurements are performed on a coaxial gallium electromagnetic thruster at discharge currents in the range of 7-23 kA. It is found that the mass bit varies quadratically with the discharge current which yields a constant exhaust velocity of 20 km/s. Increasing the electrode radius ratio of the thruster from to 2.6 to 3.4 increases the thruster efficiency from 21% to 30%. When operating with a central gallium anode, macroparticles are ejected at all energy levels tested. A central gallium cathode ejects macroparticles when the current density exceeds 3.7 10(exp 8) A/square m . A spatially and temporally broad spectroscopic survey in the 220-520 nm range is used to determine which species are present in the plasma. The spectra show that neutral, singly, and doubly ionized gallium species are present in the discharge, as well as annular electrode species at higher energy levels. Axial Langmuir triple probe measurements yield electron temperatures in the range of 0.8-3.8 eV and electron densities in the range of 8 x 10(exp )20 to 1.6 x 10(exp 21) m(exp -3) . Triple probe measurements suggest an exhaust plume with a divergence angle of 9 , and a completely doubly ionized plasma at the ablating thruster cathode.
Electromagnetic properties of neutrinos
Carlo Giunti; Alexander Studenikin
A short review on electromagnetic properties of neutrinos is presented. In spite of many efforts in the theoretical and experimental studies of neutrino electromagnetic properties, they still remain one of the main puzzles related to neutrinos.
Investigation of electromagnetic welding
Pressl, Daniel G. (Daniel Gerd)
We propose several methodologies to study and optimize the electromagnetic process for Electromagnetic Forming (EMF) and Welding (EMW), thereby lowering the necessary process energy up to a factor of three and lengthening ...
Effects of whole body exposure to extremely low frequency electromagnetic fields (ELF-EMF) on serum and liver lipid levels, in the rat
Torres-Duran, Patricia V; Ferreira-Hermosillo, Aldo; Juarez-Oropeza, Marco A; Elias-Vińas, David; Verdugo-Diaz, Leticia
Backgound The effects of extremely low-frequency electromagnetic fields (ELF-EMF) on the blood serum and liver lipid concentrations of male Wistar rats were assessed. Methods Animals were exposed to a single stimulation (2 h) of ELF-EMF (60 Hz, 2.4 mT) or sham-stimulated and thereafter sacrificed at different times (24, 48 or 96 h after beginning the exposure). Results Blood lipids showed, at 48 h stimulated animals, a significant increase of cholesterol associated to high density lipoproteins (HDL-C) than those observed at any other studied time. Free fatty acid serum presented at 24 h significant increases in comparison with control group. The other serum lipids, triacylglycerols and total cholesterol did not show differences between groups, at any time evaluated. No statistical differences were shown on total lipids of the liver but total cholesterol was elevated at 24 h with a significant decrease at 96 h (p = 0.026). The ELF-EMF stimulation increased the liver content of lipoperoxides at 24 h. Conclusion Single exposures to ELF-EMF increases the serum values of HDL-C, the liver content of lipoperoxides and decreases total cholesterol of the liver. The mechanisms for the effects of ELF-EMF on lipid metabolism are not well understand yet, but could be associated to the nitric oxide synthase EMF-stimulation. PMID:18021407
Electromagnetic Interference (Emi)
Mike Hardage; Philip D. Henry
\\u000a Electric and magnetic signals originating outside of a defibrillator may affect its operation, a phenomenon known as electromagnetic\\u000a interference (EMI). EMI usually refers to interference from environmental electromagnetic instrumentation and should be distinguished\\u000a from other sources of electromagnetic noise causing ICD malfunction (Table 1). Signals most likely to penetrate and affect\\u000a pacemakers and ICDs are electromagnetic waves or signals at
Electromagnetic Properties for Arbitrary Spin Particles: Part 1 $-$ Electromagnetic Current and Multipole Decomposition
Cédric Lorcé
In a set of two papers, we propose to study an old-standing problem, namely the electromagnetic interaction for particles of arbitrary spin. Based on the assumption that light-cone helicity at tree level and $Q^2=0$ should be conserved non-trivially by the electromagnetic interaction, we are able to derive \\emph{all} the natural electromagnetic moments for a pointlike particle of \\emph{any} spin. In this first paper, we propose a transparent decomposition of the electromagnetic current in terms of covariant vertex functions. We also define in a general way the electromagnetic multipole form factors, and show their relation with the electromagnetic moments. Finally, by considering the Breit frame, we relate the covariant vertex functions to multipole form factors.
Electromagnetic Measurements at RHIC
Hamagaki, Hideki
Electromagnetic Measurements at RHIC Hideki Hamagaki Center for Nuclear Study Graduate School of Science the University of Tokyo #12;2006/06/29 "Electromagnetic measurements at RHIC"@ATHIC 2006 Hideki;2006/06/29 "Electromagnetic measurements at RHIC"@ATHIC 2006 Hideki Hamagaki 3 Prologue  scope of EM measurements · EM
Electromagnetic Measurements at RHIC
Hamagaki, Hideki
Electromagnetic Measurements at RHIC Hideki Hamagaki Center for Nuclear Study University of Tokyo #12;2/10/2005 "Electromagnetic measurements at RHIC"@ICPAQGP 05 Hideki Hamagaki 2 Prologue · EM probe and where they are produced; #12;2/10/2005 "Electromagnetic measurements at RHIC"@ICPAQGP 05 Hideki Hamagaki
Electromagnetic Abdulaziz Hanif
Masoudi, Husain M.
Electromagnetic Propulsion Abdulaziz Hanif Electrical Engineering Department King Fahd University of spacecraft, which would be jolted through space by electromagnets, could take us farther than any of these other methods. When cooled to extremely low temperatures, electromagnets demonstrate an unusual behavior
NASA Technical Reports Server (NTRS)
Wahid, Parveen
This project involved the determination of the effective radiated power of lightning sources and the polarization of the radiating source. This requires the computation of the antenna patterns at all the LDAR site receiving antennas. The known radiation patterns and RF signal levels measured at the antennas will be used to determine the effective radiated power of the lightning source. The azimuth and elevation patterns of the antennas in the LDAR system were computed using flight test data that was gathered specifically for this purpose. The results presented in this report deal with the azimuth patterns for all the antennas and the elevation patterns for three of the seven sites.
Carbon X-ray absorption spectra of fluoroethenes and acetone: A study at the coupled cluster, density functional, and static-exchange levels of theory
Fransson, Thomas; Norman, Patrick [Department of Physics, Chemistry and Biology, Linkoeping University, SE-581 83 Linkoeping (Sweden); Coriani, Sonia [Dipartimento di Scienze Chimiche e Farmaceutiche, Universita degli Studi di Trieste, Via Licio Giorgieri 1, I-34127 Trieste (Italy); Christiansen, Ove [Department of Chemistry, University of Aarhus, DK-8000 Arhus C (Denmark)
Near carbon K-edge X-ray absorption fine structure spectra of a series of fluorine-substituted ethenes and acetone have been studied using coupled cluster and density functional theory (DFT) polarization propagator methods, as well as the static-exchange (STEX) approach. With the complex polarization propagator (CPP) implemented in coupled cluster theory, relaxation effects following the excitation of core electrons are accounted for in terms of electron correlation, enabling a systematic convergence of these effects with respect to electron excitations in the cluster operator. Coupled cluster results have been used as benchmarks for the assessment of propagator methods in DFT as well as the state-specific static-exchange approach. Calculations on ethene and 1,1-difluoroethene illustrate the possibility of using nonrelativistic coupled cluster singles and doubles (CCSD) with additional effects of electron correlation and relativity added as scalar shifts in energetics. It has been demonstrated that CPP spectra obtained with coupled cluster singles and approximate doubles (CC2), CCSD, and DFT (with a Coulomb attenuated exchange-correlation functional) yield excellent predictions of chemical shifts for vinylfluoride, 1,1-difluoroethene, trifluoroethene, as well as good spectral features for acetone in the case of CCSD and DFT. Following this, CPP-DFT is considered to be a viable option for the calculation of X-ray absorption spectra of larger {pi}-conjugated systems, and CC2 is deemed applicable for chemical shifts but not for studies of fine structure features. The CCSD method as well as the more approximate CC2 method are shown to yield spectral features relating to {pi}*-resonances in good agreement with experiment, not only for the aforementioned molecules but also for ethene, cis-1,2-difluoroethene, and tetrafluoroethene. The STEX approach is shown to underestimate {pi}*-peak separations due to spectral compressions, a characteristic which is inherent to this method.
Electromagnetically revolving sphere viscometer
NASA Astrophysics Data System (ADS)
Hosoda, Maiko; Sakai, Keiji
In this paper, we propose a new method of low viscosity measurement, in which the rolling of a probe sphere on the flat solid bottom of a sample cell is driven remotely and the revolution speed of the probe in a sample liquid gives the viscosity measurements. The principle of this method is based on the electromagnetically spinning technique that we developed, and the method is effective especially for viscosity measurements at levels below 100 mPa·s with an accuracy higher than 1%. The probe motion is similar to that in the well-known rolling sphere (ball) method. However, our system enables a steady and continuous measurement of viscosity, which is problematic using the conventional method. We also discuss the limits of the measurable viscosity range common to rolling-sphere-type viscometers by considering the accelerating motion of a probe sphere due to gravity, and we demonstrate the performance of our methods.
A strong permanent magnet-assisted electromagnetic undulator
Halbach, K.
This invention discloses an improved undulator comprising a plurality of electromagnet poles located along opposite sides of a particle beam axis with alternate north and south poles on each side of the beam to cause the beam to wiggle or undulate as it travels generally along the beam axis and permanent magnets spaced adjacent the electromagnetic poles on each side of the axis of said particle beam in an orientation sufficient to reduce the saturation of the electromagnet poles whereby the field strength of the electromagnet poles can be increased beyond the normal saturation levels of the electromagnetic poles. 4 figs.
arXiv:nucl-th/001006218Oct2000 Electromagnetic Structure of Few-Nucleon Systems: a Critical Review
Thomas Jefferson National Accelerator Facility
, including energy spectra, electromagnetic form factors, and capture reactions, is critically reviewed within-lying states, electromagnetic form factors, and low-energy capture reactions. 2. Interactions and EnergyarXiv:nucl-th/001006218Oct2000 1 Electromagnetic Structure of Few-Nucleon Systems: a Critical
Jet-cooled infrared spectra and investigation of the Torsion-rotation energy levels of methanol in the C-H stretch region
Hu, Li-Hong [Univ. of New Brunswick, Saint John (Canada); Wang, X.; Perry, D.S. [Univ. of Akron, OH (United States)] [and others
Jet-cooled absorption spectra of the C-H stretching bands of methanol have been recorded between 2965 and 3027 cm{sup -1} on two different molecular beam machines. In both cases, a color-center laser pumped by {approximately}1.6 W from a krypton ion laser at 647 nm was used to generate 8-9 mW of tunable IR radiation. The first spectrum between 2977-3027 cm{sup -1} was recorded in direct absorption with a 2 x 0.01 cm slit nozzle. The molecular rotational temperature was {approximately}17 K, and the linewidth was {approximately}75 MHz due to residual Doppler spread. Baseline subtraction was employed to suppress laser intensity fluctuations. Frequency calibration was accomplished by simultaneously recording absorption lines of ethylene and the transmission fringes of a vacuum-spaced 150 MHz-marker etalon. The second spectrum between 2965-3627 cm{sup -1} was recorded on a molecular-beam optothermal spectrometer. A mixture of a few percent methanol in He carrier was introduced to the beam chamber through a 60-{mu}m pinhole nozzle with {approximately}1atm backing pressure, giving a rotational temperature of {approximately}10 K. The beam was focused onto a He-cooled bolometer using quadrupole focusing in the flight chamber between the skimmer and the detector. In a few pathological regions, H{sub 2}O absorption completely obscured the methanol spectrum and spoiled control of the laser scan. Calibration traces were recorded to minimize errors due to gaps and drifts. On a given day the calibration interferometer drift was typically less than {approximately}10 MHz, defining the overall precision. Separations of close lines in a single scan should have precision better than 1 MHz. The two spectra were combined for analysis, with the straight absorption spectrum giving particularly nice and easily recognizable spectral patterns.
Level 2 processing for the imaging Fourier transform spectrometer GLORIA: derivation and validation of temperature and trace gas volume mixing ratios from calibrated dynamics mode spectra
NASA Astrophysics Data System (ADS)
Ungermann, J.; Blank, J.; Dick, M.; Ebersoldt, A.; Friedl-Vallon, F.; Giez, A.; Guggenmoser, T.; Höpfner, M.; Jurkat, T.; Kaufmann, M.; Kaufmann, S.; Kleinert, A.; Krämer, M.; Latzko, T.; Oelhaf, H.; Olchewski, F.; Preusse, P.; Rolf, C.; Schillings, J.; Suminska-Ebersoldt, O.; Tan, V.; Thomas, N.; Voigt, C.; Zahn, A.; Zöger, M.; Riese, M.
The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) is an airborne infrared limb-imager combining a two-dimensional infrared detector with a Fourier transform spectrometer. It was operated aboard the new German Gulfstream G550 research aircraft HALO during the Transport And Composition in the upper Troposphere/lowermost Stratosphere (TACTS) and Earth System Model Validation (ESMVAL) campaigns in summer 2012. This paper describes the retrieval of temperature and trace gas (H2O, O3, HNO3) volume mixing ratios from GLORIA dynamics mode spectra. 26 integrated spectral windows are employed in a joint fit to retrieve seven targets using consecutively a fast and an accurate tabulated radiative transfer model. Typical diagnostic quantities are provided including effects of uncertainties in the calibration and horizontal resolution along the line-of-sight. Simultaneous in-situ observations by the BAsic HALO Measurement And Sensor System (BAHAMAS), the Fast In-Situ Stratospheric Hygrometer (FISH), FAIRO, and the Atmospheric chemical Ionization Mass Spectrometer (AIMS) allow a validation of retrieved values for three flights in the upper troposphere/lowermost stratosphere region spanning polar and sub-tropical latitudes. A high correlation is achieved between the remote sensing and the in-situ trace gas data, and discrepancies can to a large fraction be attributed to differences in the probed air masses caused by different sampling characteristics of the instruments. This 1-D processing of GLORIA dynamics mode spectra provides the basis for future tomographic inversions from circular and linear flight paths to better understand selected dynamical processes of the upper troposphere and lowermost stratosphere.
ERIC Educational Resources Information Center
Cromer, Alan
When salt (NaCl) is introduced into a colorless flame, a bright yellow light (characteristic of sodium) is produced. Why doesn't the chlorine produce a characteristic color of light? The answer to this question is provided, indicating that the flame does not excite the appropriate energy levels in chlorine. (JN)
Electromagnetic structure of pion
Mello, Clayton S.; Cruz Filho, Jose P.; Da Silva, Edson O.; El-Bennich, Bruno; De Melo, J. P.; Filho, Victo S. [Laboratorio de Fisica Teorica e Computacional (LFTC), Universidade Cruzeiro do Sul, 01506-000, Sao Paulo (Brazil)
In this work, we analyze the electromagnetic structure of the pion, an elementary particle composed by a quark-antiquark bound state, by considering the calculation of its electromagnetic radius and its electromagnetic form factor in low and intermediate energy range. Such observables are determined by means of a theoretical model that takes into account the constituent quark and antiquark of the pion, in the formalism of the light-front field theory. In particular, it is considered a nonsymmetrical vertex for such a model, in which we have calculated the electromagnetic form factor of the pion in an optimized way, by varying its regulator mass, so that we can obtain the best value for the pion electromagnetic radius when compared with the experimental one. The theoretical calculations are also compared with the most recent experimental data involving the pion electromagnetic form factor and the results show very good agreement.
8.07 Electromagnetism II, Fall 2002
Zwiebach, Barton
Survey of basic electromagnetic phenomena: electrostatics, magnetostatics; electromagnetic properties of matter. Time-dependent electromagnetic fields and Maxwell's equations. Electromagnetic waves, emission, absorption, ...
Nuclear level densities in {sup 208}Bi and {sup 209}Po from the neutron spectra in the (p, n) reactions on {sup 208}Pb and {sup 209}Bi nuclei
Zhuravlev, B. V., E-mail: email@example.com; Lychagin, A. A., E-mail: firstname.lastname@example.com; Titarenko, N. N.; Demenkov, V. G.; Trykova, V. I. [Institute of Physics and Power Engineering (Russian Federation)
The spectra of neutrons from the (p, n) reactions on the {sup 208}Pb and {sup 209}Bi nuclei were measured in the proton-energy range 8-11 MeV. These measurements were performed by using a time-of-flight spectrometer of fast neutrons on the basis of the pulsed tandem accelerator EGP-15 of the Institute of Physics and Power Engineering (Obninsk, Russian Federation). A high resolution and stability of the time-of-flight spectrometermade it possible to identify reliably low-lying discrete levels alongwith the continuum section of the neutron spectra. The measured data were analyzed on the basis of the statistical equilibrium and preequilibrium models of nuclear reactions. The respective calculations were performed by using the precise formalism of Hauser-Feshbach statistical theory together with the generalized model of a superfluid nucleus and the back-shifted Fermi gas model for the nuclear-level density. The nuclear-level densities in {sup 208}Bi and {sup 209}Po were determined along with their energy dependencies and model parameters. Our results are discussed together with available experimental data and recommendations of model systematics.
Exploring the Electromagnetic Spectrum
NSDL National Science Digital Library
Students learn the basics of the electromagnetic spectrum and how various types of electromagnetic waves are related in terms of wavelength and energy. In addition, they are introduced to the various types of waves that make up the electromagnetic spectrum including, radio waves, ultraviolet waves, visible light and infrared waves. These topics help inform students before they turn to designing solutions to an overarching engineering challenge question.
Perfect electromagnetic conductor
Ismo V. Lindell; Ari Sihvola
In differential-form representation, the Maxwell equations are represented by simple differential relations between the electromagnetic two-forms and source three-forms while the electromagnetic medium is defined through a constitutive relation between the two-forms. The simplest of such relations expresses the electromagnetic two-forms as scalar multiples of one another. Because of its strange properties, the corresponding medium has been considered as nonphysical.
Meson electromagnetic form factors
Stanislav Dubnicka; Anna Z. Dubnickova
The electromagnetic structure of the pseudoscalar meson nonet is completely described by the sophisticated Unitary&Analytic model, respecting all known theoretical properties of the corresponding form factors.
How Strong are Electromagnets?
NSDL National Science Digital Library
This is an activity about electromagnetism. Using a battery and a length of wire, learners will construct an electromagnet and investigate the number of paperclips the electromagnet can hold for an electromagnet with twenty loops of wire versus one with forty loops of wire. A six to twelve volt battery, a large nail or metal rod, and insulated wire are required for this activity. This is the fourth activity in the Exploring the Earth's Magnetic Field: An IMAGE Satellite Guide to the Magnetosphere educators guide.
Megawatt Electromagnetic Plasma Propulsion
NASA Technical Reports Server (NTRS)
Gilland, James; Lapointe, Michael; Mikellides, Pavlos
The NASA Glenn Research Center program in megawatt level electric propulsion is centered on electromagnetic acceleration of quasi-neutral plasmas. Specific concepts currently being examined are the Magnetoplasmadynamic (MPD) thruster and the Pulsed Inductive Thruster (PIT). In the case of the MPD thruster, a multifaceted approach of experiments, computational modeling, and systems-level models of self field MPD thrusters is underway. The MPD thruster experimental research consists of a 1-10 MWe, 2 ms pulse-forming-network, a vacuum chamber with two 32 diffusion pumps, and voltage, current, mass flow rate, and thrust stand diagnostics. Current focus is on obtaining repeatable thrust measurements of a Princeton Benchmark type self field thruster operating at 0.5-1 gls of argon. Operation with hydrogen is the ultimate goal to realize the increased efficiency anticipated using the lighter gas. Computational modeling is done using the MACH2 MHD code, which can include real gas effects for propellants of interest to MPD operation. The MACH2 code has been benchmarked against other MPD thruster data, and has been used to create a point design for a 3000 second specific impulse (Isp) MPD thruster. This design is awaiting testing in the experimental facility. For the PIT, a computational investigation using MACH2 has been initiated, with experiments awaiting further funding. Although the calculated results have been found to be sensitive to the initial ionization assumptions, recent results have agreed well with experimental data. Finally, a systems level self-field MPD thruster model has been developed that allows for a mission planner or system designer to input Isp and power level into the model equations and obtain values for efficiency, mass flow rate, and input current and voltage. This model emphasizes algebraic simplicity to allow its incorporation into larger trajectory or system optimization codes. The systems level approach will be extended to the pulsed inductive thruster and other electrodeless thrusters at a future date.
Collum, David B.
S16 1 H and 13 C NMR Spectra (see p S3) Me N-i-Pr #12;S17 1 H and 13 C NMR Spectra (see p S3) Me NBn #12;S18 1 H and 13 C NMR Spectra (see p S4) NBn #12;S19 1 H and 13 C NMR Spectra (see p S4) NBn Me Me Me #12;S20 1 H and 13 C NMR Spectra (see p S4) N-n-Bu Me Me Me #12;S21 1 H and 13 C NMR Spectra
Experimental investigation of the hyperfine spectra of Pr I-lines: Discovery of new fine structure levels with high angular momentum
NASA Astrophysics Data System (ADS)
Siddiqui, Imran; Khan, Shamim; Windholz, Laurentius
We present 66 even and 58 odd parity newly discovered fine structure levels of Pr I with high angular momentum: J = 15/2, 17/2 and 19/2 and 21/2. Spectral lines in the range 4200 Ĺ to 7500 Ĺ were experimentally investigated using laser induced fluorescence spectroscopy in a hollow cathode discharge lamp. The levels were discovered by analysis of the recorded hyperfine patterns of the investigated transitions. More than 800 spectral lines could be classified with help of these levels. Supplementary material in the form of one pdf file available from the Journal web page at http://dx.doi.org/10.1140/epjd/e2014-50025-7
NISTHB 150-11 NVLAP Electromagnetic Compatibility and Telecommunications Bethany Hackett Bradley. #12;NISTHB 150-11 NVLAP Electromagnetic Compatibility and Telecommunications Bethany Hackett Bradley Programs Dennis Camell Electromagnetics Division Physical Measurement Laboratory http://dx.doi.org/10
Electromagnetic shielding in quantum metrology
NASA Astrophysics Data System (ADS)
Jin, Yao; Yu, Hongwei
The dynamics of the quantum Fisher information of the parameters of the initial atomic state and atomic transition frequency is studied, in the framework of open quantum systems, for a static polarizable two-level atom coupled in the multipolar scheme to a bath of fluctuating vacuum electromagnetic fields without and with the presence of a reflecting boundary. Our results show that in the case without a boundary, the electromagnetic vacuum fluctuations always cause the quantum Fisher information of the initial parameters and thus the precision limit of parameter estimation to decrease. Remarkably, however, with the presence of a boundary, the quantum Fisher information becomes position and atomic polarization dependent and, as a result, it may be enhanced as compared to that in the case without a boundary and may even be shielded from the influence of the vacuum fluctuations in certain circumstances as if it were a closed system.
NSDL National Science Digital Library
This is a lesson about the electromagnetic spectrum. Learners will read two pages of information about the electromagnetic spectrum and answer questions in an accompanying worksheet. This activity is from the Stanford Solar Center's All About the Sun: Sun and Stars activity guide for Grades 5-8 and can also accompany the Stanford Solar Center's Build Your Own Spectroscope activity.
NSDL National Science Digital Library
This tutorial introduces students to the concepts of electromagnetic waves, wavelength, and the electromagnetic spectrum. Diagrams and written descriptions explain how wavelength is measured and explore the traditional divisions of the spectrum: radio, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.
Tunability enhanced electromagnetic wiggler
Schlueter, Ross D. (Albany, CA); Deis, Gary A. (Livermore, CA)
The invention discloses a wiggler used in synchrotron radiation sources and free electron lasers, where each pole is surrounded by at least two electromagnetic coils. The electromagnetic coils are energized with different amounts of current to provide a wide tunable range of the on-axis magnetic flux density, while preventing magnetic saturation of the poles.
NSDL National Science Digital Library
VU Bioengineering RET Program,
Students design and construct an electromagnet that must pick up 10 staples. They begin with only minimal guidance, and after the basic concept is understood, are informed of the properties that affect the strength of that magnet. They conclude by designing their own electromagnet to complete the challenge of separating scrap steel from scrap aluminum for recycling and share it with the class.
Electromagnetic Analysis: Concrete Results
Karine Gandolfi; Christophe Mourtel; Francis Olivier
Abstract Although the possibility of attacking smart - cards by analyz - ing their electromagnetic power radiation repeatedly appears in research papers, all accessible references evade the essence of reporting conclusive experiments where actual cryptographic algorithms such as des or rsa were successfully attacked This work describes electromagnetic experiments conducted on three dif - ferent cmos chips, featuring di erent
Tunability enhanced electromagnetic wiggler
Schlueter, R.D.; Deis, G.A.
The invention discloses a wiggler used in synchrotron radiation sources and free electron lasers, where each pole is surrounded by at least two electromagnetic coils. The electromagnetic coils are energized with different amounts of current to provide a wide tunable range of the on-axis magnetic flux density, while preventing magnetic saturation of the poles. 14 figs.
Introducing Electromagnetic Field Momentum
ERIC Educational Resources Information Center
Hu, Ben Yu-Kuang
I describe an elementary way of introducing electromagnetic field momentum. By considering a system of a long solenoid and line charge, the dependence of the field momentum on the electric and magnetic fields can be deduced. I obtain the electromagnetic angular momentum for a point charge and magnetic monopole pair partially through dimensional…
Theoretical energy level spectra and transition data for 4p$^6$4d$^2$, 4p$^6$4d4f and 4p$^5$4d$^3$ configurations of W$^{36+}$ ion
Bogdanovich, P
The ab initio quasirelativistic Hartree-Fock method developed specifically for the calculation of spectral parameters of heavy atoms and highly charged ions is used to derive transition data for multicharged tungsten ion. The configuration interaction method is applied to include electron correlation effects. The relativistic effects are taken into account in the Breit-Pauli approximation for quasirelativistic Hartree-Fock radial orbitals. The energy level spectra, radiative lifetimes $\\tau$, Lande $g$-factors are calculated for the $\\mathrm{4p^64d^2}$, $\\mathrm{4p^64d4f}$ and $\\mathrm{4p^54d^3}$ configurations of W$^{36+}$ ion. The transition wavelengths $\\lambda$, spontaneous transition probabilities $A$, oscillator strengths $gf$ and line strengths $S$ for the electric dipole, electric quadrupole, electric octupole and magnetic dipole transitions among the levels of these configurations are tabulated.
Theoretical energy level spectra and transition data for 4p$^6$4d, 4p$^6$4f and 4p$^5$4d$^2$ configurations of W$^{37+}$ ion
Bogdanovich, P
The ab initio quasirelativistic Hartree-Fock method developed specifically for the calculation of spectral parameters of heavy atoms and highly charged ions was applied to determine atomic data for tungsten ions. The correlation effects were included by adopting configuration interaction method. The Breit-Pauli approximation for quasirelativistic Hartree-Fock radial orbitals was employed to take into account relativistic effects. The energy level spectra, radiative lifetimes, Lande factors $g$ were calculated for the $\\mathrm{4p^64d}$, $\\mathrm{4p^64f}$ and $\\mathrm{4p^54d^2}$ configurations of W$^{37+}$ ion. The atomic data, namely, the transition wavelengths, spontaneous emission rates and oscillator strengths for the electric dipole, electric quadrupole and magnetic dipole transitions among and within the levels of these configurations are tabulated.
Spectra of bigyrotropic magnetic photonic crystals
I. L. Lyubchanskii; N. N. Dadoenkova; M. I. Lyubchanskii; E. A. Shapovalov; A. Lakhtakia; T. H. M. Rasing
We calculated the photonic band gap spectra of a one-dimensional magnetic photonic crystal made of alternating layers of bigyrotropic magnetic yttrium-iron garnet and nonmagnetic gadolinium gallium garnet. The forbidden regimes or band gaps in the electromagnetic wave spectrum were numerically obtained for the transversal magneto-optical configuration and compared with those for the polar and longitudinal magneto-optical configurations.
Electromagnetic probes of the QGP
E. L. Bratkovskaya; O. Linnyk; W. Cassing
We investigate the properties of the QCD matter across the deconfinement phase transition in the scope of the parton-hadron string dynamics (PHSD) transport approach. We present here in particular the results on the electromagnetic radiation, i.e. photon and dilepton production, in relativistic heavy-ion collisions. By comparing our calculations for the heavy-ion collisions to the available data, we determine the relative importance of the various production sources and address the possible origin of the observed strong elliptic flow $v_2$ of direct photons. We argue that the different centrality dependence of the hadronic and partonic sources for direct photon production in nucleus-nucleus collisions can be employed to shed some more light on the origin of the photon $v_2$ "puzzle". While the dilepton spectra at low invariant mass show in-medium effects like an enhancement from multiple baryonic resonance formation or a collisional broadening of the vector meson spectral functions, the dilepton yield at high invariant masses (above 1.1 GeV) is dominated by QGP contributions for central heavy-ion collisions at ultra-relativistic energies. This allows to have an independent view on the parton dynamics via their electromagnetic massive radiation.
NASA Astrophysics Data System (ADS)
Matthews, R. K.; Stepanek, S. A.
Electromagnetic wave testing, which represents a relatively new test technique that involves the union of several disciplines (aerothermodynamics, electromagnetics, materials/structures, and advanced diagnostics) is introduced. The essence of this new technique deals with the transmission and possible distortion of electromagnetic waves (RF or IR) as they pass through the bow shock, flow field, and electromagnetic window of a missile flying at hypersonic speeds. Variations in gas density along the optical path can cause significant distortion of the electromagnetic waves and, therefore the missile seeker system may not effectively track the target. Two specific test techniques are described. The first example deals with the combining of a wind tunnel and an RF range while the second example discusses the complexities of evaluating IR seeker system performance.
[Conformational states of NADH molecules in hydrated shell under weak electromagnetic irradiation].
The work deals with spectra of capillary waves of water distillate and water solution of NADH and dynamics of NADH under electromagnetic irradiation in the range of millimeters at different space frequencies of surface wave k. PMID:25868340
Velocity anisotropy effect in pump-probe spectra of cesium in a micrometric thickness optical cell
NASA Astrophysics Data System (ADS)
Ghosh, P. N.; Mitra, S.; Ray, B.; Krasteva, A.; Slavov, D.; Todorov, P.; Cartaleva, S.
The pump-probe spectra in a cell of micrometric thickness containing cesium vapor are reported. The line shape and nonlinear features observed in the case of fluorescence in the direction parallel to the cell windows and the transmission spectra observed along the propagation direction of the probe beam show considerable differences in the spectral profiles. We observed Electromagnetically Induced Transparency (EIT) and enhanced Velocity Selective Optical Pumping (VSOP) signals. Atoms moving nearly parallel to the windows and perpendicular to the collinear pump and probe beams will see much lower Doppler shift of incident frequencies and hence will lead to considerable narrowing of the Doppler background in the fluorescence spectra. The coherence decay rate is also low for such atoms as they do not meet with the cell walls. A theoretical model based on five level optical Bloch equations is used to simulate the spectra. The Doppler convolution includes all possible orientation of atomic velocities with respect to the laser beam direction. The simulated curves reproduce the observed sharp EIT peaks and enhanced broad VSOP signals for the closed probe transition in the fluorescence and absorption spectra. The observed effect of the light intensity and temperature change on the non-linear features is reproduced by the simulation.
IUPAC critical evaluation of the rotational-vibrational spectra of water vapor. Part IV. Energy levels and transition wavenumbers for D216O, D217O, and D218O
NASA Astrophysics Data System (ADS)
Tennyson, Jonathan; Bernath, Peter F.; Brown, Linda R.; Campargue, Alain; Császár, Attila G.; Daumont, Ludovic; Gamache, Robert R.; Hodges, Joseph T.; Naumenko, Olga V.; Polyansky, Oleg L.; Rothman, Laurence S.; Vandaele, Ann Carine; Zobov, Nikolai F.; Dénes, Nóra; Fazliev, Alexander Z.; Furtenbacher, Tibor; Gordon, Iouli E.; Hu, Shui-Ming; Szidarovszky, Tamás; Vasilenko, Irina A.
This paper is the fourth of a series of papers reporting critically evaluated rotational-vibrational line positions, transition intensities, pressure dependences, and energy levels, with associated critically reviewed assignments and uncertainties, for all the main isotopologues of water. This paper presents energy level and transition data for the following doubly and triply substituted isotopologues of water: D216O, D217O, and D218O. The MARVEL (Measured Active Rotational-Vibrational Energy Levels) procedure is used to determine the levels, the lines, and their self-consistent uncertainties for the spectral regions 0-14 016, 0-7969, and 0-9108 cm-1 for D216O, D217O, and D218O, respectively. For D216O, D217O, and D218O, 53 534, 600, and 12 167 lines are considered, respectively, from spectra recorded in absorption at room temperature and in emission at elevated temperatures. The number of validated energy levels is 12 269, 338, and 3351 for D216O, D217O, and D218O, respectively. The energy levels have been checked against the ones determined, with an average accuracy of about 0.03 cm-1, from variational rovibrational computations employing exact kinetic energy operators and an accurate potential energy surface. Furthermore, the rovibrational labels of the energy levels have been validated by an analysis of the computed wavefunctions using the rigid-rotor decomposition (RRD) scheme. The extensive list of MARVEL lines and levels obtained is deposited in the Supplementary Material of this paper, in a distributed information system applied to water, W@DIS, and on the official MARVEL website, where they can easily be retrieved.
Electromagnetic fluctuations and normal modes of a drifting relativistic plasma
Ruyer, C.; Gremillet, L.; Bénisti, D. [CEA, DAM, DIF, F-91297 Arpajon (France)] [CEA, DAM, DIF, F-91297 Arpajon (France); Bonnaud, G. [CEA, Saclay, INSTN, F-91191 Gif-sur-Yvette (France)] [CEA, Saclay, INSTN, F-91191 Gif-sur-Yvette (France)
We present an exact calculation of the power spectrum of the electromagnetic fluctuations in a relativistic equilibrium plasma described by Maxwell-Jüttner distribution functions. We consider the cases of wave vectors parallel or normal to the plasma mean velocity. The relative contributions of the subluminal and supraluminal fluctuations are evaluated. Analytical expressions of the spatial fluctuation spectra are derived in each case. These theoretical results are compared to particle-in-cell simulations, showing a good reproduction of the subluminal fluctuation spectra.
NASA Technical Reports Server (NTRS)
Korman, Valentin (Inventor); Wiley, John T. (Inventor); Duffell, Amanda G. (Inventor)
A liquid level sensing system includes waveguides disposed in a liquid and distributed along a path with a gap between adjacent waveguides. A source introduces electromagnetic energy into the waveguides at a first end of the path. A portion of the electromagnetic energy exits the waveguides at a second end of the path. A detector measures the portion of the electromagnetic energy exiting the second end of the path.
[Electromagnetic fields: their biological effects and regulation].
Nakagawa, M
Concern over the effects of humans of ELF-(extremely low frequency; less than 300 Hz) electromagnetic fields has rapidly increased in recent years. The effects seem to be related to gene level aberrations such as carcinogenesis and developmental malformations, but it is difficult to obtain experimental evidences on field effects. Several safety guidelines or permissible doses have been proposed for electromagnetic wave, but they mainly cover the range of microwave frequencies. Three of the guidelines made in 1989-1990 included ELF-electromagnetic fields and two newly approved guidelines on power-frequency electromagnetic fields appeared in 1990. However, they adopted considerably different values based on different theoretical standpoints. Generally, the concept of electromagnetic fields appears to be confused with that of magnetic field and thus the ideas for protective measures conflict between the two. The author first presented the concepts of electromagnetic and magnetic fields, then briefly discussed their biological effects together with the underlying mechanism, and lastly described these drafts on safety standards or permissible doses. Since subtle and difficult problems remain to be resolved, further investigation will be required in order to put these guidelines into practice. PMID:1753442
NSDL National Science Digital Library
This interactive, online module reviews the basics of the the electromagnetic spectrum and makes the connection between radiation theory and the images we get from weather satellites. Students will learn about: the electromagnetic spectrum; electromagnetic waves; the electromagnetic spectrum and radiation theory; and how satellite radiometers "see" different sections of the spectrum. The module is part of an online course for grades 7-12 in satellite meteorology, which includes 10 interactive modules. The site also includes lesson plans developed by teachers and links to related resources. Each module is designed to serve as a stand-alone lesson, however, a sequential approach is recommended. Designed to challenge students through the end of 12th grade, middle school teachers and students may choose to skim or skip a few sections.
Geant4 Electromagnetic Physics
S. Chauvie; V. Grichine; P. Gumplinger; V. Ivanchenko; R. Kokoulin; S. Magni; M. Maire; P. Nieminen; M. G. Pia; A. Rybin; L. Urban
An overview of the main features of Geant4 electromagnetic physics is presented. The role played by advanced software engineering methodologies and by Object Oriented technology is illustrated. The main physics functionalities are described.
Purely electromagnetic spacetimes
B. V. Ivanov
Electrovacuum solutions devoid of usual mass sources are classified in the case of one, two and three commuting Killing vectors. Three branches of solutions exist. Electromagnetically induced mass terms appear in some of them.
The classical geometrization electromagnetism
C. A. Duarte
Following the line of the history, if by one side the electromagnetic theory was consolidated on the 19th century, the emergence of the special and the general relativity theories on the 20th century opened possibilities of further developments, with the search for the unification of the gravitation and the electromagnetism on a single unified theory. Some attempts to the geometrization of the electromagnetism emerged in this context, where these first models resided strictly on a classical basis. Posteriorly, they were followed by more complete and embracing quantum field theories. The present work reconsiders the classical viewpoint, with the purpose of showing that in a first order of approximation the electromagnetism constitutes a geometric structure aside other phenomena as gravitation. Even though being limited, the model is consistent and offers the possibility of an experimental test of validity.
Electromagnetism in the Movies.
ERIC Educational Resources Information Center
Everitt, Lori R.; Patterson, Evelyn T.
Describes how the authors used portions of popular movies to help students review concepts related to electromagnetism. Movies used and concepts covered in the review are listed, and a sample activity is described. (WRM)
Microslots : scalable electromagnetic instrumentation
Maguire, Yael G., 1975-
This thesis explores spin manipulation, fabrication techniques and boundary conditions of electromagnetism to bridge the macroscopic and microscopic worlds of biology, chemistry and electronics. This work is centered around ...
An opening electromagnetic transducer
NASA Astrophysics Data System (ADS)
Sun, Yanhua; Kang, Yihua
Tubular solenoids have been widely used without any change since an electrical wire was discovered to create magnetic fields by Hans Christian Oersted in 1820 and thereby the wire was first coiled as a helix into a solenoid coil by William Sturgeon in 1823 and was improved by Joseph Henry in 1829 [see http://www.myetymology.com/encyclopedia/History_of_the_electricity.html; J. M. D. Coey, Magnetism and Magnetic Materials (Cambridge University Press, New York, 2010); and F. Winterberg, Plasma Phys. 8, 541553 (1996)]. A magnetic control method of C-shaped carrying-current wire is proposed, and thereby a new opening electromagnetic transducer evidently differing from the traditional tubular solenoid is created, capable of directly encircling and centering the acted objects in it, bringing about convenient and innovative electromagnetic energy conversion for electromagnetic heating, electromagnetic excitation, physical information capture, and electro-mechanical motion used in science research, industry, and even biomedical activities.
Inverse problems in electromagnetics
Chen, Xudong, 1977-
Two inverse problems in electromagnetics are investigated in this thesis. The first is the retrieval of the effective constitutive parameters of metamaterials from the measurement of the reflection and the transmission ...
Rigorous theory of spectra and radiation for a model in quantum electrodynamics
Asao Arai
We study rigorously the problem of the lamb shift and the spontaneous emission of light in a framework of nonrelativistic quantum electrodynamics by using an exactly soluble model of a harmonic oscillator atom interacting with a quantized electromagnetic field. We show that, under the perturbation of the electromagnetic field, all the point spectra corresponding to the excited states of the
THERMAL RADIATION The type of electromagnetic radiation that is pertinentThe type of electromagnetic radiation that is pertinent
Kostic, Milivoje M.
THERMAL RADIATION The type of electromagnetic radiation that is pertinentThe type of electromagnetic radiation that is pertinent to heat transfer is the thermal radiation emitted as a result of the strength of these activities at the microscopic level, and the rate of thermal radiation emission increases
Classical Trajectories and Quantum Spectra
NASA Technical Reports Server (NTRS)
Mielnik, Bogdan; Reyes, Marco A.
A classical model of the Schrodinger's wave packet is considered. The problem of finding the energy levels corresponds to a classical manipulation game. It leads to an approximate but non-perturbative method of finding the eigenvalues, exploring the bifurcations of classical trajectories. The role of squeezing turns out decisive in the generation of the discrete spectra.
Charging Ahead: An Introduction to Electromagnetism.
ERIC Educational Resources Information Center
Shafer, Larry E.
This guide explores the connection between electricity and magnetism with middle level and high school students. The phenomenon of electromagnetism is broken down into four lesson plans that provide students and teachers with a carefully constructed yet easy way to learn about their history. All four activities prompt students to use inexpensive,…
Electromagnetic modeling of plasmonic nanostructures
NASA Astrophysics Data System (ADS)
Pavaskar, Prathamesh
In this thesis, plasmonic properties of metal nanostructures are investigated by electromagnetic simulations using the finite difference time domain (FDTD) method. Chapter 1 covers the background knowledge required to read this thesis. It talks about the fundamentals of the FDTD method, the physics of plasmonics and a brief description of photocatalysis. In chapter 2, we perform optimization of plasmonic nanoparticle geometries. An iterative optimization algorithm is used to determine the configuration of the nanoparticles that gives the maximum electric field intensity at the center of the cluster. We observe that the optimum configurations of these clusters have mirror symmetry about the axis of planewave propagation, but are otherwise non-symmetric and non-intuitive. The maximum field intensity is found to increase monotonically with the number nanoparticles in the cluster, producing intensities that are 2500 times larger than the incident electromagnetic field. In chapter 3, evaporated thin films are imaged with high resolution transmission electron microscopy (HRTEM), to reveal the structure of the semicontinuous metal island film with sub-nm resolution. The electric field distributions and the absorption spectra of these semicontinuous island film geometries are calculated using the finite difference time domain (FDTD) method and compared with the experimentally measured absorption spectra. In addition to that, we calculate the SERS enhancement factors and photocatalytic enhancement factors of these films. We also study the effect of annealing on these films, which results in a large reduction in electric field strength due to increased nanoparticle spacing. In chapter 4, we study the effects of surrounding nanoparticles on a plasmonic hot spot. From our simulations, we show that the surrounding film contributes significantly to the electric field intensity at the hot spot by focusing energy to it. Widening of the gap size causes a decrease in the intensity at the hot spot. However, these island-like nanoparticle hot spots are shown to be robust to gap size than nanoparticle dimer geometries, studied previously. In fact, the main factor in determining the hot spot intensity is the focusing effect of the surrounding nano-islands. In chapter 5, we demonstrate plasmon-enhanced photocatalytic water splitting, and reduction of CO2 with H2O to form hydrocarbon fuels. Under visible illumination, we observe enhancements of up to 66X in the photocatalytic splitting of water in TiO2 with the addition of Au nanoparticles. We also perform a systematic study of the mechanisms of Au nanoparticle/TiO 2-catalyzed photoreduction of CO2 and water vapor over a wide range of wavelengths. In this case, under visible light illumination, we observe a 24-fold enhancement in the photocatalytic activity due to the intense local electromagnetic fields created by the surface plasmons of the Au nanoparticles. Above the plasmon resonance, under ultraviolet radiation we observe a reduction in the photocatalytic activity. Electromagnetic simulations indicate that the improvement of photocatalytic activity in the visible range is caused by the local electric field enhancement near the TiO2 surface, rather than by the direct transfer of charge between the two materials. In chapter 6, I will talk about a method for fabricating arrays of plasmonic nanoparticles with separations on the order of 1nm using an angle evaporation technique. High resolution transmission electron microscopy (HRTEM) is used to resolve the small separations achieved between nanoparticles fabricated on thin SiN membranes. These nearly touching metal nanoparticles produce extremely high electric field intensities when irradiated with laser light. We perform surface enhanced Raman spectroscopy (SERS) a non-resonant dye molecule (p-ATP) deposited on the nanoparticle arrays using confocal micro-Raman spectroscopy. Our results show significant enhancement when the incident laser is polarized parallel to the axis of the nanoparticle pairs, whereas no enhancement is observed for the p
Electromagnetic attachment mechanism
NASA Technical Reports Server (NTRS)
Monford, Leo G., Jr. (inventor)
An electromagnetic attachment mechanism is disclosed for use as an end effector of a remote manipulator system. A pair of electromagnets, each with a U-shaped magnetic core with a pull-in coil and two holding coils, are mounted by a spring suspension system on a base plate of the mechanism housing with end pole pieces adapted to move through openings in the base plate when the attractive force of the electromagnets is exerted on a strike plate of a grapple fixture affixed to a target object. The pole pieces are spaced by an air gap from the strike plate when the mechanism first contacts the grapple fixture. An individual control circuit and power source is provided for the pull-in coil and one holding coil of each electromagnet. A back-up control circuit connected to the two power sources and a third power source is provided for the remaining holding coils. When energized, the pull-in coils overcome the suspension system and air gap and are automatically de-energized when the pole pieces move to grapple and impose a preload force across the grapple interface. A battery backup is a redundant power source for each electromagnet in each individual control circuit and is automatically connected upon failure of the primary source. A centerline mounted camera and video monitor are used in cooperation with a target pattern on the reflective surface of the strike plate to effect targeting and alignment.
Electromagnetically induced absorption via incoherent collisions
Yang Xihua [Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701 (United States); Department of Physics, Shanghai University, Shanghai 200444 (China); Sheng Jiteng; Xiao Min [Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701 (United States)
We conduct theoretical studies on electromagnetically induced absorption via incoherent collisions in an inhomogeneously broadened ladder-type three-level system with the density-matrix approach. The effects of the collision-induced coherence decay rates as well as the probe laser field intensity on the probe field absorption are examined. It is shown that with the increase of the collisional decay rates in a moderate range, a narrow dip due to electromagnetically induced transparency superimposed on the Doppler-broadened absorption background can be turned into a narrow peak under the conditions that the probe field intensity is not very weak as compared to the pump field, which results from the enhancement of constructive interference and suppression of destructive interference between one-photon and multiphoton transition pathways. The physical origin of the collision-assisted electromagnetically induced absorption is analyzed with a power-series solution of the density-matrix equations.
EMACK electromagnetic launcher commissioning
NASA Astrophysics Data System (ADS)
Deis, D. W.; Scherbarth, D. W.; Ferrentino, G. L.
The Laboratory Demonstration Electromagnetic Launcher Program (EMACK) was initiated in April 1979, with the objective to design, construct, and demonstrate a complete electromagnetic launcher (EML) system capable of accelerating projectiles of substantial mass to velocities significantly greater than those achievable with conventional chemical systems. The last hardware was installed in late 1981. During February 1982, a series of five test shots was made to evaluate the system's performance. Particular attention is given to the parameters of the final, as-built hardware, and the results of the commissioning tests. The results of these tests have demonstrated the viability of the components required for large scale electromagnetic launchers. It has been shown that large projectiles with velocities significantly greater than those achievable by chemical systems can be accelerated intact.
Aircraft electromagnetic compatibility
NASA Technical Reports Server (NTRS)
Clarke, Clifton A.; Larsen, William E.
Illustrated are aircraft architecture, electromagnetic interference environments, electromagnetic compatibility protection techniques, program specifications, tasks, and verification and validation procedures. The environment of 400 Hz power, electrical transients, and radio frequency fields are portrayed and related to thresholds of avionics electronics. Five layers of protection for avionics are defined. Recognition is given to some present day electromagnetic compatibility weaknesses and issues which serve to reemphasize the importance of EMC verification of equipment and parts, and their ultimate EMC validation on the aircraft. Proven standards of grounding, bonding, shielding, wiring, and packaging are laid out to help provide a foundation for a comprehensive approach to successful future aircraft design and an understanding of cost effective EMC in an aircraft setting.
Electromagnetic properties of baryons
Ledwig, T.; Pascalutsa, V.; Vanderhaeghen, M. [Institut fuer Kernphysik, Universitaet Mainz, D-55099 Mainz (Germany); Martin-Camalich, J. [Departamento de Fisica Teorica and IFIC, Universidad de Valencia-CSIC, Spain and Department of Physics and Astronomy, University of Sussex, BN1 9Qh, Brighton (United Kingdom)
We discuss the chiral behavior of the nucleon and {Delta}(1232) electromagnetic properties within the framework of a SU(2) covariant baryon chiral perturbation theory. Our one-loop calculation is complete to the order p{sup 3} and p{sup 4}/{Delta} with {Delta} as the {Delta}(1232)-nucleon energy gap. We show that the magnetic moment of a resonance can be defined by the linear energy shift only when an additional relation between the involved masses and the applied magnetic field strength is fulfilled. Singularities and cusps in the pion mass dependence of the {Delta}(1232) electromagnetic moments reflect a non-fulfillment. We show results for the pion mass dependence of the nucleon iso-vector electromagnetic quantities and present preliminary results for finite volume effects on the iso-vector anomalous magnetic moment.
Electromagnetic particle simulation codes
NASA Technical Reports Server (NTRS)
Pritchett, P. L.
Electromagnetic particle simulations solve the full set of Maxwell's equations. They thus include the effects of self-consistent electric and magnetic fields, magnetic induction, and electromagnetic radiation. The algorithms for an electromagnetic code which works directly with the electric and magnetic fields are described. The fields and current are separated into transverse and longitudinal components. The transverse E and B fields are integrated in time using a leapfrog scheme applied to the Fourier components. The particle pushing is performed via the relativistic Lorentz force equation for the particle momentum. As an example, simulation results are presented for the electron cyclotron maser instability which illustrate the importance of relativistic effects on the wave-particle resonance condition and on wave dispersion.
Electromagnetic properties of baryons
T. Ledwig; J. Martin-Camalich; V. Pascalutsa; M. Vanderhaeghen
We discuss the chiral behavior of nucleon and Delta(1232) electromagnetic properties within the framework of a SU(2) covariant baryon chiral perturbation theory. Our one-loop calculation is complete to the order p^3 and p^4/Delta with Delta as the Delta(1232)-nucleon energy gap. We show that the magnetic moment of a resonance can be defined through the linear energy shift only when an additional relation between the involved masses and the applied magnetic field strength is fulfilled. Singularities and cusps in the pion mass dependence of the Delta(1232) electromagnetic moments reflect a non-fulfillment. We show results for the pion mass dependence of the nucleon iso-vector electromagnetic quantities and present results for finite volume effects on the iso-vector anomalous magnetic moment.
David Branch; E. Baron; David J. Jeffery
Supernova flux and polarization spectra bring vital information on the geometry, physical conditions, and composition structure of the ejected matter. For some supernovae the circumstellar matter is also probed by the observed spectra. Some of this information can be inferred directly from the observed line profiles and fluxes, but because of the Doppler broadening and severe line blending, interpretation often involves the use of synthetic spectra. The emphasis in this Chapter is on recent results obtained with the help of synthetic spectra.
Microwave Spectra of Fluoroformyloxyl and Fluorosulfate Radicals
S. Urban; J. Varga; L. Kolesniková; Z. Meltzerová; T. Uhlíková; J. Koucký; P. Kania; H. Beckers; H. Willner
Rotational spectra of fluoroformyloxyl (FCO_2) and fluorosulfate radicals (FSO_3) were studied in their ground states. The spectra measured involve fine structures due to a unpaired electron as well as hyperfine interaction features due to 19F nucleus that can give rise to an additional hyperfine doubling of levels. These radicals are of the atmospheric interest, for example the FCO_2 radical may
A class of non-null toroidal electromagnetic fields and its relation to the model of electromagnetic knots
NASA Astrophysics Data System (ADS)
Arrayás, Manuel; Trueba, José L.
An electromagnetic knot is an electromagnetic field in vacuum in which the magnetic lines and the electric lines coincide with the level curves of a pair of complex scalar fields ? and ? (see equations (A.1), (A.2)). When electromagnetism is expressed in terms of electromagnetic knots, it includes mechanisms for the topological quantization of the electromagnetic helicity, the electric charge, the electromagnetic energy inside a cavity and the magnetic flux through a superconducting ring. In the case of electromagnetic helicity, its topological quantization depends on the linking number of the field lines, both electric and magnetic. Consequently, to find solutions of the electromagnetic knot equations with nontrivial topology of the field lines has important physical consequences. We study a new class of solutions of Maxwell?s equations in vacuum Arrayás and Trueba (2011 arXiv:1106.1122) obtained from complex scalar fields that can be interpreted as maps {{S}3}\\to {{S}2}, in which the topology of the field lines is that of the whole torus-knot set. Thus this class of solutions is built as electromagnetic knots at initial time. We study some properties of those fields and consider if detection based on the energy and momentum observables is possible.
Biological effects of electromagnetic fields
Anderson, L.E.
Natural background levels of atmospheric electric and geomagnetic field levels are extremely low. Over the past several decades, however, human beings and other life forms on this planet have been subjected to a dramatically changing electromagnetic milieu. Exponential increases in exposure to EM fields have occurred, largely because of technological advances associated with increased use of electricity; e.g. expanding power generation and transmission systems, the increased use of wireless communications, and radar. EM field generating devices have proliferated in industrial plants, office buildings, homes, public transportation systems, and elsewhere. Significant increases have occurred in EM field strengths spanning all frequency ranges; therefore, this paper presents a brief overview of the potential impacts of these fields, primarily at extremely low frequencies (ELF), but also at MW and RF. 2 refs.
Electromagnetic propulsion test facility
NASA Technical Reports Server (NTRS)
Gooder, S. T.
A test facility for the exploration of electromagnetic propulsion concept is described. The facility is designed to accommodate electromagnetic rail accelerators of various lengths (1 to 10 meters) and to provide accelerating energies of up to 240 kiloJoules. This accelerating energy is supplied as a current pulse of hundreds of kiloAmps lasting as long as 1 millisecond. The design, installation, and operating characteristics of the pulsed energy system are discussed. The test chamber and its operation at pressures down to 1300 Pascals (10 mm of mercury) are described. Some aspects of safety (interlocking, personnel protection, and operating procedures) are included.
Improved Electromagnetic Brake
NASA Technical Reports Server (NTRS)
Martin, Toby B.
A proposed design for an electromagnetic brake would increase the reliability while reducing the number of parts and the weight, relative to a prior commercially available electromagnetic brake. The reductions of weight and the number of parts could also lead to a reduction of cost. A description of the commercial brake is prerequisite to a description of the proposed electromagnetic brake. The commercial brake (see upper part of figure) includes (1) a permanent magnet and an electromagnet coil on a stator and (2) a rotor that includes a steel contact plate mounted, with tension spring loading, on an aluminum hub. The stator is mounted securely on a stationary object, which would ordinarily be the housing of a gear drive or a motor. The rotor is mounted on the shaft of the gear drive or motor. The commercial brake nominally operates in a fail-safe (in the sense of normally braking) mode: In the absence of current in the electromagnet coil, the permanent magnet pulls the contact plate, against the spring tension, into contact with the stator. To release the brake, one excites the electromagnet with a current of the magnitude and polarity chosen to cancel the magnetic flux of the permanent magnet, thereby enabling the spring tension to pull the contact plate out of contact with the stator. The fail-safe operation of the commercial brake depends on careful mounting of the rotor in relation to the stator. The rotor/stator gap must be set with a tolerance between 10 and 15 mils (between about 0.25 and about 0.38 mm). If the gap or the contact pad is thicker than the maximum allowable value, then the permanent magnetic field will not be strong enough to pull the steel plate across the gap. (For this reason, any contact pad between the contact plate and the stator must also be correspondingly thin.) If the gap exceeds the maximum allowable value because of shaft end play, it becomes impossible to set the brake by turning off the electromagnet current. Although it may still be possible to set the brake by applying an electromagnet current to aid the permanent magnetic field instead of canceling it, this action can mask an out-of-tolerance condition in the brake and it does not restore the fail-safe function of setting the brake when current is lost.
Electromagnetic analysis and design of electromagnetic devices using permanent magnets
M. Nagrial; J. Rizk
The design of electromagnetic devices requires accurate calculation of the design parameters. The finite element method is extensively employed in the design of electrical machines and other electromagnetic and magnetic systems. The finite element method provides an accurate and simple approach to parameters evaluation from the determination of electromagnetic field distribution. The details of designed permanent magnet machines and magnetic
Electromagnetically Induced Flows Michiel de Reus
Vuik, Kees
Electromagnetically Induced Flows in Water Michiel de Reus 8 maart 2013 () Electromagnetically Conclusion and future research () Electromagnetically Induced Flows 2 / 56 #12;1 Introduction 2 Maxwell Navier Stokes equations 5 Simulations 6 Conclusion and future research () Electromagnetically Induced
8.07 Electromagnetism II, Fall 2005
Bertschinger, Edmund
This course is the second in a series on Electromagnetism beginning with Electromagnetism I (8.02 or 8.022). It is a survey of basic electromagnetic phenomena: electrostatics; magnetostatics; electromagnetic properties of ...
How Astronomers Use Spectra to Learn About the Sun and Other Stars
NSDL National Science Digital Library
This is a booklet about spectra and their usefulness to astronomers. Learners will read about the electromagnetic spectrum, how atomic physics is used to obtain information out of stellar spectra, and how the Doppler effect is used to measure stellar motions. An activity at the end allows learners to analyze and identify several emission lines in the spectrum of the Sun.
Spectrally isomorphic Dirac systems: graphene in electromagnetic field
Vit Jakubsky
We construct the new one-dimensional Dirac Hamiltonians that are spectrally isomorphic (not isospectral) with the known exactly solvable models. Explicit formulas for their spectra and eigenstates are provided. The operators are utilized for description of Dirac fermions in graphene in presence of an inhomogeneous electromagnetic field. We discuss explicit, physically relevant, examples of spectrally isomorphic systems with both non-periodic and periodic electromagnetic barriers. In the latter case, spectrally isomorphic two- and three-gap systems associated with the Ablowitz-Kaup-Newell-Segur hierarchy are considered.
Spectrally isomorphic Dirac systems: Graphene in an electromagnetic field
NASA Astrophysics Data System (ADS)
Jakubský, Vít
We construct the new one-dimensional Dirac Hamiltonians that are spectrally isomorphic (not isospectral) with the known exactly solvable models. Explicit formulas for their spectra and eigenstates are provided. The operators are utilized for the description of Dirac fermions in graphene in the presence of an inhomogeneous electromagnetic field. We discuss explicit, physically relevant, examples of spectrally isomorphic systems with both nonperiodic and periodic electromagnetic barriers. In the latter case, spectrally isomorphic two- and three-gap systems associated with the Ablowitz-Kaup-Newell-Segur hierarchy are considered.
Analytical model for electromagnetic cascades in rotating electric field
Nerush, E. N.; Bashmakov, V. F.; Kostyukov, I. Yu. [Institute of Applied Physics, Russian Academy of Sciences, 603950 Nizhny Novgorod (Russian Federation)
Electromagnetic cascades attract a lot of attention as an important quantum electrodynamics effect that will reveal itself in various electromagnetic field configurations at ultrahigh intensities. We study cascade dynamics in rotating electric field analytically and numerically. The kinetic equations for the electron-positron plasma and gamma-quanta are formulated. The scaling laws are derived and analyzed. For the cascades arising far above the threshold the dependence of the cascade parameters on the field frequency is derived. The spectra of high-energy cascade particles are calculated. The analytical results are verified by numerical simulations.
Electromagnetic shock absorber
S. Mirzaei; S. M. Saghaiannejad; V. Tahani; M. Moallem
This paper introduces a novel passive suspension system for ground vehicles. The system is based a flexible electromagnetic shock absorber (EMSA). In the proposed system, it is attempted: (a) to select a variable high damping coefficient usable in a car; (b) physical dimensions and the geometry of EMSA not to be very different from mechanical shock absorbers; and (c) its
Global electromagnetic induction
R. G. Roberts
Methods of analysis of long period geomagnetic variations (periods over a few hours), the available electromagnetic response function estimates, and the effect of lateral inhomogeneity within the Earth are reviewed. Recent advances in the inversion of response function data to produce conductivitydepth profiles are mentioned, and aspects of the inverse problem specific to global (spherical Earth) induction are discussed. There
S. Baillet; J. C. Mosher; R. M. Leahy
There has been tremendous advances in our ability to produce images of human brain function. Applications of functional brain imaging extend from improving our understanding of the basic mechanisms of cognitive processes to better characterization of pathologies that impair normal function. Magnetoencephalography (MEG) and electroencephalography (EEG) (MEG\\/EEG) localize neural electrical activity using noninvasive measurements of external electromagnetic signals. Among the
Electromagnetic pulsar spindown
I. Contopoulos
We evaluate the result of the recent pioneering numerical simulations in Spitkovsky~2006 on the spindown of an oblique relativistic magnetic dipole rotator. Our discussion is based on our experience from two idealized cases, that of an aligned dipole rotator, and that of an oblique split-monopole rotator. We conclude that the issue of electromagnetic pulsar spindown may not have been resolved yet.
Equivalence principles and electromagnetism
NASA Technical Reports Server (NTRS)
Ni, W.-T.
The implications of the weak equivalence principles are investigated in detail for electromagnetic systems in a general framework. In particular, it is shown that the universality of free-fall trajectories (Galileo weak equivalence principle) does not imply the validity of the Einstein equivalence principle. However, the Galileo principle plus the universality of free-fall rotation states does imply the Einstein principle.
Electromagnetism and Gravitation
Kenneth Dalton
The classical concept of "mass density" is not fundamental to the quantum theory of matter. Therefore, mass density cannot be the source of gravitation. Here, we treat electromagnetic energy, momentum, and stress as its source. The resulting theory predicts that the gravitational potential near any charged elementary particle is many orders of magnitude greater than the Newtonian value.
Adaptive electromagnetic shunt damping
Dominik Niederberger; Sam Behrens; Andrew J. Fleming; S. O. R. Moheimani; Manfred Morari
This paper presents a new type of passive vibration control: adaptive electromagnetic shunt damping. We propose a single-mode resonant shunt controller that adapts to environmental conditions using two different adaptation strategies. The first technique is based on minimizing the root mean square (RMS) vibration, while the second minimizes the phase difference between two measurable signals. An experimental comparison shows that
Electromagnetic radiations from rocks
Toshio Ogawa; Kazuo Oike; Taiji Miura
To test the possibility of the emission of electromagnetic waves from rocks, experiments have been made to measure the electric field by using mainly granite samples that were struck together or struck by a hammer or a weight and were fractured by a bending moment. The wide-band (10 Hz to 100 kHz) waveforms of electric signals were digitally recorded. Roughly
Simple Superconducting "Permanent" Electromagnet
NASA Technical Reports Server (NTRS)
Israelson, Ulf E.; Strayer, Donald M.
Proposed short tube of high-temperature-superconducting material like YBa2Cu3O7 acts as strong electromagnet that flows as long as magnetic field remains below critical value and temperature of cylinder maintained sufficiently below superconducting-transition temperature. Design exploits maximally anisotropy of high-temperature-superconducting material.
Noncontact Electromagnetic Vibration Source
NASA Technical Reports Server (NTRS)
Namkung, Min; Fulton, James P.; Wincheski, Buzz A.
Metal aircraft skins scanned rapidly in vibration tests. Relatively simple combination of permanent magnets and electromagnet serves as noncontact vibration source for nondestructive testing of metal aircraft skins. In test, source excites vibrations, and vibration waveforms measured, then analyzed for changes in resonances signifying cracks and other flaws.
What are Electromagnetic Metamaterials?
NSDL National Science Digital Library
Metamaterials are artificial structures that display properties beyond those available in naturally occuring materials. Materials interact with light and other electromagnetic fields. Because of this, materials can be used to control light in various ways, forming the basis for optical devices. This website from Duke University gives more details and graphs.
S. Takada; T. Makimura; M. Matsubara
This patent describes an electromagnetic fuel injector for an internal combustion engine. This device is seated in a valve housing with a fuel injection nozzle and a valve seat at its front end and a guide hole extending along its axis to contain the valve body. The valve body of this device includes a cylindrical slide unit which has a
Electromagnetic Momentum, Energy, and Mass
F. Rohrlich
Electromagnetic systems of finite mass (m > 0) and of zero mass (m = 0) are considered. For both cases the electromagnetic energy and momentum are computed and are shown to lead to essentially different formulas. An invariant expression for the electromagnetic mass in m > 0 systems is derived. All m > 0 results are then specialized to the
Spectroscopy Interaction of electromagnetic radiation
Gerwert, Klaus
Spectroscopy 691 Interaction of electromagnetic radiation with atoms or molecules #12;Bacteriorhodopsin: a light-driven proton pump 486 #12;Electromagnetic Radiation 692 harmonic wave (Maxwell): y;Spectroscopy 691 Interaction of electromagnetic radiation with atoms or molecules two processes: emission
Computational Electronics and Electromagnetics
DeFord, J.F.
The Computational Electronics and Electromagnetics thrust area is a focal point for computer modeling activities in electronics and electromagnetics in the Electronics Engineering Department of Lawrence Livermore National Laboratory (LLNL). Traditionally, they have focused their efforts in technical areas of importance to existing and developing LLNL programs, and this continues to form the basis for much of their research. A relatively new and increasingly important emphasis for the thrust area is the formation of partnerships with industry and the application of their simulation technology and expertise to the solution of problems faced by industry. The activities of the thrust area fall into three broad categories: (1) the development of theoretical and computational models of electronic and electromagnetic phenomena, (2) the development of useful and robust software tools based on these models, and (3) the application of these tools to programmatic and industrial problems. In FY-92, they worked on projects in all of the areas outlined above. The object of their work on numerical electromagnetic algorithms continues to be the improvement of time-domain algorithms for electromagnetic simulation on unstructured conforming grids. The thrust area is also investigating various technologies for conforming-grid mesh generation to simplify the application of their advanced field solvers to design problems involving complicated geometries. They are developing a major code suite based on the three-dimensional (3-D), conforming-grid, time-domain code DSI3D. They continue to maintain and distribute the 3-D, finite-difference time-domain (FDTD) code TSAR, which is installed at several dozen university, government, and industry sites.
Combined quantum mechanics (TDDFT) and classical electrodynamics (Mie theory) methods for calculating surface enhanced Raman and hyper-Raman spectra.
Mullin, Jonathan; Valley, Nicholas; Blaber, Martin G; Schatz, George C
Multiscale models that combine quantum mechanics and classical electrodynamics are presented, which allow for the evaluation of surface-enhanced Raman (SERS) and hyper-Raman scattering spectra (SEHRS) for both chemical (CHEM) and electrodynamic (EM) enhancement mechanisms. In these models, time-dependent density functional theory (TDDFT) for a system consisting of the adsorbed molecule and a metal cluster fragment of the metal particle is coupled to Mie theory for the metal particle, with the surface of the cluster being overlaid with the surface of the metal particle. In model A, the electromagnetic enhancement from plasmon-excitation of the metal particle is combined with the chemical enhancement associated with a static treatment of the molecule-metal structure to determine overall spectra. In model B, the frequency dependence of the Raman spectrum of the isolated molecule is combined with the enhancements determined in model A to refine the enhancement estimate. An equivalent theory at the level of model A is developed for hyper-Raman spectra calculations. Application to pyridine interacting with a 20 nm diameter silver sphere is presented, including comparisons with an earlier model (denoted G), which combines plasmon enhanced fields with gas-phase Raman (or hyper-Raman) spectra. The EM enhancement factor for spherical particles at 357 nm is found to be 10(4) and 10(6) for SERS and SEHRS, respectively. Including both chemical and electromagnetic mechanisms at the level of model A leads to enhancements on the order of 10(4) and 10(9) for SERS and SEHRS. PMID:22946645
Electromagnetic Environment of Grounding Systems
NASA Astrophysics Data System (ADS)
Lefouili, M.; Hafsaoui, I.; Kerroum, K.; Drissi, K. El Khamlichi
Electromagnetic compatibility (EMC) and lightning protection studies in large installations require knowledge of spatial and temporal distribution of electromagnetic fields in case of lightning and power system faults. A new hybrid method for modeling electromagnetic environment of grounding systems is developed in this work. The electromagnetic fields in the surrounding soil are determined from the previously calculated current distribution using dipoles theory with analytical formulas. The model can be used to predict the EM environment of grounding systems because it can calculate electromagnetic fields in any points of interest.
Optimal classification of HCI spectra
Gaigalas, G; Rudzikas, Z
Energy levels of highly charged ions as a rule cannot be classified using LS coupling due to rapid increase of relativistic effects. It is suggested, for optimal classification of energy spectra, to calculate them in LS coupling and to transform the weights of the wave functions, obtained after diagonalization of the energy matrix, to the other coupling schemes. F-like ions are considered as an example.
Broadband cavity electromagnetically induced transparency
Wei Xiaogang [Department of Physics, Florida International University, Miami, Florida 33199 (United States); College of Physics, Jilin University, Changchun 130023 (China); Wang Yanhua [Department of Physics, Florida International University, Miami, Florida 33199 (United States); College of Physics and Electronics, Shanxi University, Taiyuan 030006 (China); Zhang Jiepeng [Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Physics Division P-23, Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States); Zhu Yifu [Department of Physics, Florida International University, Miami, Florida 33199 (United States)
Cavity electromagnetically induced transparency (EIT) is created in a three-level atomic system confined in a cavity and coupled to a free-space control laser and is manifested as a narrow transmission peak of a probe laser coupled into the cavity mode and tuned to the two-photon Raman resonance with the control laser. Cavity EIT can be observed with a control laser detuned from the atomic transition frequency in a range limited by the vacuum Rabi splitting of two cavity-atom normal modes. This leads to the broadband cavity EIT obtained in the coupled-cavity-atom system with a free-space, broadband control laser. We report an experimental observation of broadband cavity EIT in cold Rb atoms with a frequency-modulated control laser and discuss its application in multichannel and multifrequency light memory.
Tiernan, M.
Crack spectra derived from velocity data have been shown to exhibit systematics which reflect microstructural and textural differences between samples (Warren and Tiernan, 1980). Further research into both properties and information content of crack spectra have yielded the following: Spectral features are reproducible even at low pressures; certain observed spectral features may correspond to non-in-situ crack populations created during sample retrieval; the functional form of a crack spectra may be diagnostic of the sample's grain texture; hysteresis is observed in crack spectra between up and down pressure runs - it may be due to friction between the faces of closed crack populations.
Electromagnetic wave energy converter
NASA Technical Reports Server (NTRS)
Bailey, R. L. (inventor)
Electromagnetic wave energy is converted into electric power with an array of mutually insulated electromagnetic wave absorber elements each responsive to an electric field component of the wave as it impinges thereon. Each element includes a portion tapered in the direction of wave propagation to provide a relatively wideband response spectrum. Each element includes an output for deriving a voltage replica of the electric field variations intercepted by it. Adjacent elements are positioned relative to each other so that an electric field subsists between adjacent elements in response to the impinging wave. The electric field results in a voltage difference between adjacent elements that is fed to a rectifier to derive dc output power.
Magnetism and Electromagnetism
NSDL National Science Digital Library
Kuphaldt, Tony R.
All About Circuits is a website that â??provides a series of online textbooks covering electricity and electronics.â?ť Written by Tony R. Kuphaldt, the textbooks available here are wonderful resources for students, teachers, and anyone who is interested in learning more about electronics. This specific section, Magnetism and Electromagnetism, is the fourteenth chapter in Volume I â?? Direct Current. A few of the topics covered in this chapter include: Permanent magnets; Electromagnetic induction; and Mutual inductance. Diagrams and detailed descriptions of concepts are included throughout the chapter to provide users with a comprehensive lesson. Visitors to the site are also encouraged to discuss concepts and topics using the All About Circuits discussion forums (registration with the site is required to post materials).
Isotropic metamaterial electromagnetic lens
E. Verney; B. Sauviac; C. R. Simovski
Several authors have recently exhibited the focusing activity in the domain of so-called electromagnetic lenses. These lenses are parallel-plate layers of metamaterials whose properties can be described in terms of negative index of refraction. Known works on this subject refer to 2D structures. This work is our first attempt to show the focusing effect by a parallel-plate layer of a
Gravitation and Electromagnetism
B. G. Sidharth
The realms of gravitation, belonging to Classical Physics, and Electromagnetism, belonging to the Theory of the Electron and Quantum Mechanics have remained apart as two separate pillars, inspite of a century of effort by Physicists to reconcile them. In this paper it is argued that if we extend ideas of Classical spacetime to include in addition to non integrability non commutavity also, then such a reconcilation is possible.
Quaternion Gravi-Electromagnetism
A. S. Rawat; O. P. S. Negi
Defining the generalized charge, potential, current and generalized fields as complex quantities where real and imaginary parts represent gravitation and electromagnetism respectively, corresponding field equation, equation of motion and other quantum equations are derived in manifestly covariant manner. It has been shown that the field equations are invariant under Lorentz as well as duality transformations. It has been shown that the quaternionic formulation presented here remains invariant under quaternion transformations.
Banded electromagnetic stator core
Fanning, Alan W. (San Jose, CA); Gonzales, Aaron A. (San Jose, CA); Patel, Mahadeo R. (San Jose, CA); Olich, Eugene E. (Aptos, CA)
A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups.
Banded electromagnetic stator core
Fanning, A.W.; Gonzales, A.A.; Patel, M.R.; Olich, E.E.
A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups. 5 figures.
Banded electromagnetic stator core
Fanning, Alan W. (San Jose, CA); Gonzales, Aaron A. (San Jose, CA); Patel, Mahadeo R. (San Jose, CA); Olich, Eugene E. (Aptos, CA)
A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups.
Banded electromagnetic stator core
Fanning, A.W.; Gonzales, A.A.; Patel, M.R.; Olich, E.E.
A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups. 5 figs.
Electromagnetic tornadoes in space
Chang, T.; Crew, G.B.; Retterer, J.M.
The exotic phenomenon of energetic-ion conic formation by plasma waves in the magnetosphere is considered. Two particular transverse heating mechanisms are reviewed in detail; lower-hybrid energization of ions in the boundary layer of the plasma sheet and electromagnetic ion cyclotron resonance heating in the central region of the plasma sheet. Mean particle calculations, plasma simulations and analytical treatments of the heating processes are described.
Method of electromagnetic exploration
Nekut, A.G. Jr.
A method is described of electromagnetic exploration comprising the following steps: obtaining measures of two horizontal components of the earth's magnetic field at each reference sites; obtaining a measure of the vertical component of the earth's magnetic field for at least one exploratory site; and determining a measure of a multidimensional earth resistivity structure by correlating the measures of horizontal and vertical components of the earth's magnetic field.
Fractional Electromagnetic Waves
J. F. Gómez; J. J. Rosales; J. J. Bernal; V. I. Tkach; M. Guía
In the present work we consider the electromagnetic wave equation in terms of the fractional derivative of the Caputo type. The order of the derivative being considered is 0 <\\gamma<1. A new parameter \\sigma, is introduced which characterizes the existence of the fractional components in the system. We analyze the fractional derivative with respect to time and space, for \\gamma = 1 and \\gamma = 1/2 cases.
The KLOE electromagnetic calorimeter
M. Adinolfi; F. Ambrosino; A. Antonelli; M. Antonelli; F. Anulli; G. Barbiellini; G. Bencivenni; S. Bertolucci; C. Bini; C. Bloise; V. Bocci; F. Bossi; P. Branchini; G. Cabibbo; R. Caloi; P. Campana; M. Casarsa; G. Cataldi; F. Ceradini; F. Cervelli; P. Ciambrone; E De Lucia; P De Simone; G De Zorzi; S Dell'Agnello; A. Denig; A. Di Domenico; C. Di Donato; S Di Falco; A. Doria; O. Erriquez; A. Farilla; A. Ferrari; M. L Ferrer; G. Finocchiaro; C. Forti; A. Franceschi; P. Franzini; M. L Gao; C. Gatti; P. Gauzzi; A. Giannasi; S. Giovannella; E. Graziani; H. G Han; S. W Han; X. Huang; M. Incagli; L. Ingrosso; L. Keeble; W. Kim; C. Kuo; G. Lanfranchi; J. Lee-Franzini; T. Lomtadze; C. S Mao; M. Martemianov; W. Mei; R. Messi; S. Miscetti; S. Moccia; M. Moulson; S. Müller; F. Murtas; L. Pacciani; M. Palomba; M. Palutan; E. Pasqualucci; L. Passalacqua; A. Passeri; D. Picca; G. Pirozzi; L. Pontecorvo; M. Primavera; P. Santangelo; E. Santovetti; G. Saracino; R. D Schamberger; B. Sciascia; F. Scuri; I. Sfiligoi; P. Silano; T. Spadaro; E. Spiriti; L. Tortora; P. Valente; B. Valeriani; G. Venanzoni; A. Ventura; S. Wölfle; Y. Wu; Y. G Xie; P. F Zema; C. D Zhang; J. Q Zhang; P. P. Zhao
The KLOE detector was designed primarily for the study of CP violation in neutral kaon decays at DA?NE, the Frascati ?-factory. The detector consists of a tracker and an electromagnetic calorimeter. A lead-scintillating-fiber sampling calorimeter satisfies best the requirements of the experiment, providing adequate energy resolution and superior timing accuracy. We describe in the following the construction of the calorimeter,
Gravito-electromagnetic analogies
NASA Astrophysics Data System (ADS)
Costa, L. Filipe O.; Natário, José
We reexamine and further develop different gravito-electromagnetic (GEM) analogies found in the literature, and clarify the connection between them. Special emphasis is placed in two exact physical analogies: the analogy based on inertial fields from the so-called "1+3 formalism", and the analogy based on tidal tensors. Both are reformulated, extended and generalized. We write in both formalisms the Maxwell and the full exact Einstein field equations with sources, plus the algebraic Bianchi identities, which are cast as the source-free equations for the gravitational field. New results within each approach are unveiled. The well known analogy between linearized gravity and electromagnetism in Lorentz frames is obtained as a limiting case of the exact ones. The formal analogies between the Maxwell and Weyl tensors are also discussed, and, together with insight from the other approaches, used to physically interpret gravitational radiation. The precise conditions under which a similarity between gravity and electromagnetism occurs are discussed, and we conclude by summarizing the main outcome of each approach.
Electromagnetically induced transparency with amplification in superconducting circuits.
Joo, Jaewoo; Bourassa, Jérôme; Blais, Alexandre; Sanders, Barry C
We show that controlling relative phases of electromagnetic fields driving an atom with a ?-configuration energy-level structure enables optical susceptibility to be engineered in novel ways. In particular, relative-phase control can yield electromagnetically induced transparency but with the benefit that the transparency window is sandwiched between an absorption and an amplification band rather than between two absorption bands in typical electromagnetically induced transparency. We show that this new phenomenon is achievable for a microwave field interacting with a fluxonium superconducting circuit. PMID:20868042
Observations of ELF electromagnetic waves associated with equatorial spread F
NASA Technical Reports Server (NTRS)
Kelley, M. C.; Holtet, J. A.; Tsurutani, B. T.
Extreme low frequency electromagnetic waves have been observed below the F peak in the equatorial ionosphere by instruments onboard OGO-6. Electrostatic wave observations indicate that the steep gradient was unstable to the process which causes equatorial spread F above the region where the electromagnetic waves were observed. The data are very similar to observations near the polar cusp and give further evidence that ELF waves are excluded from regions of rapid and irregular density increases. Low level electromagnetic waves with similar properties were occasionally observed on the nightside by the OVI-17 electric field sensor and may be plasmaspheric hiss which has propagated to low altitude.
Theory of electromagnetic fluctuations for magnetized multi-species plasmas
Navarro, Roberto E., E-mail: firstname.lastname@example.com; Muńoz, Víctor [Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Araneda, Jaime [Departamento de Física, Universidad de Concepción, Concepción 4070386 (Chile); Moya, Pablo S. [NASA Goddard Space Flight Center, Heliophysics Science Division, Geospace Physics Laboratory, Mail Code 673, Greenbelt, Maryland 20771 (United States); Department of Physics, Catholic University of America, Washington, D. C. 20064 (United States); Vińas, Adolfo F. [NASA Goddard Space Flight Center, Heliophysics Science Division, Geospace Physics Laboratory, Mail Code 673, Greenbelt, Maryland 20771 (United States); Valdivia, Juan A. [Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Centro de Estudios Interdisciplinarios Básicos y Aplicados en Complejidad, CEIBA complejidad, Bogotá (Colombia)
Analysis of electromagnetic fluctuations in plasma provides relevant information about the plasma state and its macroscopic properties. In particular, the solar wind persistently sustains a small but detectable level of magnetic fluctuation power even near thermal equilibrium. These fluctuations may be related to spontaneous electromagnetic fluctuations arising from the discreteness of charged particles. Here, we derive general expressions for the plasma fluctuations in a multi-species plasma following arbitrary distribution functions. This formalism, which generalizes and includes previous works on the subject, is then applied to the generation of electromagnetic fluctuations propagating along a background magnetic field in a plasma of two proton populations described by drifting bi-Maxwellians.
Deduction of the chemical state and the electronic structure of Nd{sub 2}Fe{sub 14}B compound from X-ray photoelectron spectroscopy core-level and valence-band spectra
Wang, Jing; Liang, Le [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhang, Lanting, E-mail: email@example.com, E-mail: firstname.lastname@example.com [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Hirano Institute for Materials Innovation, Shanghai Jiao Tong University, Shanghai 200240 (China); Sun, Limin, E-mail: email@example.com, E-mail: email@example.com [Instrumental Analysis Center, Shanghai Jiao Tong University, Shanghai 200240 (China); Hirano, Shinichi [Hirano Institute for Materials Innovation, Shanghai Jiao Tong University, Shanghai 200240 (China)
Characterization of chemical state and electronic structure of the technologically important Nd{sub 2}Fe{sub 14}B compound is attractive for understanding the physical nature of its excellent magnetic properties. X-ray photoelectron spectroscopy (XPS) study of such rare-earth compound is important and also challenging due to the easy oxidation of surface and small photoelectron cross-sections of rare-earth 4f electrons and B 2p electrons, etc. Here, we reported an investigation based on XPS spectra of Nd{sub 2}Fe{sub 14}B compound as a function of Ar ion sputtering time. The chemical state of Fe and that of B in Nd{sub 2}Fe{sub 14}B compound can be clearly determined to be 0 and ?3, respectively. The Nd in Nd{sub 2}Fe{sub 14}B compound is found to have the chemical state of close to +3 instead of +3 as compared with the Nd in Nd{sub 2}O{sub 3}. In addition, by comparing the valence-band spectrum of Nd{sub 2}Fe{sub 14}B compound to that of the pure Fe, the contributions from Nd, Fe, and B to the valence-band structure of Nd{sub 2}Fe{sub 14}B compound is made more clear. The B 2p states and B 2s states are identified to be at ?11.2 eV and ?24.6 eV, respectively, which is reported for the first time. The contribution from Nd 4f states can be identified both in XPS core-level spectrum and XPS valence-band spectrum. Although Nd 4f states partially hybridize with Fe 3d states, Nd 4f states are mainly localized in Nd{sub 2}Fe{sub 14}B compound.
Psychological studies in nonionizing electromagnetic energy research.
O'Connor, M E
Research on nonionizing electromagnetic (NIEM) energy has focused on potential hazards, and to a lesser degree beneficial applications, of radiofrequency (RF) fields and extremely low frequency (ELF) fields. The history of research on the potential biological effects of NIEM contains many psychological investigations. These psychological investigations were conducted primarily in the discipline of biopsychology and included interdisciplinary cooperation with engineering, physical sciences, and other disciplines not routinely associated with psychology. The current recommended exposure level for RF is based on behavioral observations of laboratory animals. Psychology has been and continues to be in the midst of controversy regarding the ability of low-frequency, low-level electromagnetic energy or electric and magnetic fields to affect living organisms. PMID:8340784
Space physics and the teaching of undergraduate electromagnetism
NASA Astrophysics Data System (ADS)
Lopez, R.; Mitchell, E.
Space physics is not a subject typically found in the undergraduate curriculum and it is rare even at the graduate level On the other hand the basis of space physics is electromagnetism and the motion of charged particles which is a common topics in both the introductory and advanced undergraduate physics curriculum This presentation will discuss various topics commonly found in both introductory and upper-division electricity and magnetism classes where examples from space physics may facilitate student understanding or provide interesting real-life examples of electromagnetism in action We chose these examples based on current research around student difficulties with electromagnetic phenomena and we will provide preliminary evidence on the efficacy of our interventions I will also discuss research in visualization of 3-D magnetic fields and the implications for teach both space physics and regular electromagnetism at both the graduate and undergraduate levels
Coherent hybrid electromagnetic field imaging
Cooke, Bradly J. (Jemez Springs, NM); Guenther, David C. (Los Alamos, NM)
An apparatus and corresponding method for coherent hybrid electromagnetic field imaging of a target, where an energy source is used to generate a propagating electromagnetic beam, an electromagnetic beam splitting means to split the beam into two or more coherently matched beams of about equal amplitude, and where the spatial and temporal self-coherence between each two or more coherently matched beams is preserved. Two or more differential modulation means are employed to modulate each two or more coherently matched beams with a time-varying polarization, frequency, phase, and amplitude signal. An electromagnetic beam combining means is used to coherently combine said two or more coherently matched beams into a coherent electromagnetic beam. One or more electromagnetic beam controlling means are used for collimating, guiding, or focusing the coherent electromagnetic beam. One or more apertures are used for transmitting and receiving the coherent electromagnetic beam to and from the target. A receiver is used that is capable of square-law detection of the coherent electromagnetic beam. A waveform generator is used that is capable of generation and control of time-varying polarization, frequency, phase, or amplitude modulation waveforms and sequences. A means of synchronizing time varying waveform is used between the energy source and the receiver. Finally, a means of displaying the images created by the interaction of the coherent electromagnetic beam with target is employed.
Alexei V. Filippenko
The temporal evolution of the optical spectra of various types of supernovae (SNe) is illustrated, in part to aid observers classifying supernova candidates. Type II SNe are defined by the presence of hydrogen, and they exhibit a very wide variety of photometric and spectroscopic properties. Among hydrogen-deficient SNe (Type I), three subclasses are now known: those whose early-time spectra show
Cognitive Effects of Electromagnetic Fields in Humans
Alan W. Preece
\\u000a Electromagnetic fields interact with human tissue in a number of ways, depending on power level and frequency, and have been\\u000a long suspected by some to give rise to harmful effects. In particular, the use of a mobile phone against the head has aroused\\u000a suspicions of various cognitive effects. Accordingly, there have been a large number of studies of behavioural effects
G. H. Dieke; H. M. Crosswhite
The present status of the knowledge of the structure of the spectra of ; the doubly and triply ionized spectra of the rare earths is derived partly from ; experimental data of the emission spectra of the free ions which provide the ; energy level scheme in great detail but are difficuit and laborious to analyze. ; For the lower
Radio frequency electromagnetic fields: mild hyperthermia and safety standards
John A. D'Andrea; John M. Ziriax; Eleanor R. Adair
This chapter is a short review of literature that serves as the basis for current safe exposure recommendations by ICNIRP (International Commission on Non-Ionizing Radiation Protection, 1998). and the IEEE C95.1 (IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3kHz to 300GHz, 2005) for exposure to radio frequency electromagnetic radiation (RF-EMF). Covered here
Electromagnetic Force as consequence of the Geometry of Minkowskian Spacetime
J. Buitrago
By describing the dynamical evolution of a test charged particle in the presence of an electromagnetic field as a succession of infinitesimal Lorentz boosts and rotations it is possible to obtain the Lorentz Force of Electrodynamics. A consequence of this derivation at the classical level is that, given the existence of electric and magnetic fields, the form of the electromagnetic force acting on the particle can be regarded as arising from the geometry of Minkowskian spacetime.
Electromagnetic WavesElectromagnetic Waves In this chapter we will review selected properties of electromagnetic waves since
Rutledge, Steven
Electromagnetic WavesElectromagnetic Waves In this chapter we will review selected properties of electromagnetic waves since radar involves the transmission, propagation and scattering of EM waves by various is the electrostatic force between two point charges. #12;Electromagnetic WavesElectromagnetic Waves Electric fields
Optical Spectra and Electronic Structure
NASA Astrophysics Data System (ADS)
Liu, Guokui; Beitz, James V.
Much of our knowledge of the electronic properties of actinides in solutions and solids is obtained from optical spectroscopy. One of the features that sets actinide spectra apart from those of other elements in the periodic table, aside from the lanthanide series, is that their f-orbitals can be considered both as containing optically active electrons and as belonging to the core of inner shells. As a result of this dominant characteristic, the spectra of these elements, particularly of the lower valence states, are moderately insensitive to changes in the ionic environment. Although ion-ligand interactions shift and split the energy levels of the f-orbitals, the scale of this crystal-field splitting is generally smaller than the intra-ionic Coulomb interaction and spin-orbit coupling. The relative insensitivity of these f-electrons to external forces also means that for these elements there is a close connection between energy levels in compounds and those in gaseous free atoms and ions. Table 18.1 lists the scales of various mechanisms of electronic interactions that will be discussed in this chapter through analysis and modeling of the optical spectra of the various valence states of actinide ions in solutions and compounds.
Electromagnetic studies in geothermal regions
NASA Astrophysics Data System (ADS)
Berktold, A.
During the past 25 yr, nearly all available electromagnetic and geoelectric techniques have been tested for their usefulness in geothermal exploration and exploitation. Dipole-dipole profiling, audiomagnetotellurics and controlled source electromagnetic methods are examples of those which have proven to be rather efficient for geothermal exploration. From the hundreds of field surveys which have been performed in many geothermal regions of the world, a large variety of geothermal regions and local geothermal systems, with different geological, hydrological and heat transfer characteristics, has been found to exist. Depending on the combination of these different characteristics each geothermal region or system presents a new problem which may need a different field technique or group of field techniques for optimal exploration. Despite these problems, new geothermal regions have been detected and structures and processes in geothermal systems are now much better understood. For example, advances have been made in the study of (a) the characteristics of porous/permeable hot water/vapor reservoirs and of fractioned zones for hot water/vapor circulation and production (b) the distribution and movement of cold meteoric and of hot water (c) the thermal insulation of reservoirs by cap-rocks (d) convective and/or conductive heat transfer and (e) the thermal influence of magma intrusions to high crustal levels. New exploration techniques, data analysis procedures and model calculations have been developed in the course of research in geothermal areas. They include the controlled source electromagnetic methods, the remote reference field technique and the development of better and faster algorithms for direct and inverse model calculations. Problems for the future are (a) the development and improvement of equipment and field techniques for more precise delineation and resolution of the conductivity distribution in geothermal areas especially those with productive zones of high porosity/permeability and fracturing, (b) the improvement of computerised data analysis in the field to optimise progress during the field measurements and (c) the development of more efficient interpretation procedures for the rather inhomogeneous conductivity distribution which exists in most geothermal areas.
NASA Astrophysics Data System (ADS)
Nishida, Kiwamu
The observation of seismic hum from 2 to 20 mHz, also known as Earth's background free oscillations, has been established. Recent observations by broad-band seismometers show simultaneous excitation of Love waves (fundamental toroidal modes) and Rayleigh waves (fundamental spheroidal modes). The excitation amplitudes above 10 mHz can be explained by random shear traction sources on Earth's surface. With estimated source distributions, the most likely excitation mechanism is a linear coupling between ocean infragravity waves and seismic surface waves through seafloor topography. Observed Love and Rayleigh wave amplitudes below 5 mHz suggest that surface pressure sources could also contribute to their excitations, although the amplitudes have large uncertainties due to the high noise levels of the horizontal components. To quantify the observation, we develop a new method for estimation of the source spectra of random tractions on Earth's surface by modelling cross-spectra between pairs of stations. The method is to calculate synthetic cross-spectra for spatially isotropic and homogeneous excitations by random shear traction and pressure sources, and invert them with the observed cross-spectra to obtain the source spectra. We applied this method to the IRIS, ORFEUS, and F-net records from 618 stations with three components of broad-band seismometers for 2004-2011. The results show the dominance of shear traction above 5 mHz, which is consistent with past studies. Below 5 mHz, however, the spectral amplitudes of the pressure sources are comparable to those of shear traction. Observed acoustic resonance between the atmosphere and the solid Earth at 3.7 and 4.4 mHz suggests that atmospheric disturbances are responsible for the surface pressure sources, although non-linear ocean wave processes are also candidates for the pressure sources. Excitation mechanisms of seismic hum should be considered as a superposition of the processes of the solid Earth, atmosphere and ocean as a coupled system.
Electromagnetic field and cosmic censorship
Koray Düzta?
We construct a gedanken experiment in which an extremal Kerr black hole interacts with a test electromagnetic field. Using Teukolsky's solutions for electromagnetic perturbations in Kerr spacetime, and the conservation laws imposed by the energy momentum tensor of the electromagnetic field and the Killing vectors of the spacetime, we prove that this interaction cannot convert the black hole into a naked singularity, thus cosmic censorship conjecture is not violated in this case.
Electromagnetic Theory 3 Volume Set
NASA Astrophysics Data System (ADS)
Heaviside, Oliver
Volume 1: Preface; 1. Introduction; 2. Outline of the electromagnetic connections; 3. The elements of vectorial algebra and analysis; 4. Theory of plane electromagnetic waves; Appendix. Volume 2: Preface; 5. Mathematics and the age of the earth; 6. Pure diffusion of electric displacement; 7. Electromagnetic waves and generalised differentiation; 8. Generalised differentiation and divergent series; Appendix. Volume 3: 9. Waves from moving sources; 10. Waves in the ether.
Electromagnetic field and cosmic censorship
Düzta?, Koray
We construct a gedanken experiment in which an extremal Kerr black hole interacts with a test electromagnetic field. Using Teukolsky's solutions for electromagnetic perturbations in Kerr spacetime, and the conservation laws imposed by the energy momentum tensor of the electromagnetic field and the Killing vectors of the spacetime, we prove that this interaction cannot convert the black hole into a naked singularity, thus cosmic censorship conjecture is not violated in this case.
Electromagnetic field and cosmic censorship
NASA Astrophysics Data System (ADS)
Düzta?, Koray
We construct a gedanken experiment in which an extremal Kerr black hole interacts with a test electromagnetic field. Using Teukolsky's solutions for electromagnetic perturbations in Kerr spacetime, and the conservation laws imposed by the energy momentum tensor of the electromagnetic field and the Killing vectors of the spacetime, we prove that this interaction cannot convert the black hole into a naked singularity, thus cosmic censorship conjecture is not violated in this case.
Achievable Transverse Cylindrical Electromagnetic Mode
R. Chen; X. Li
The system of Maxwell equations with an initial condition in a vacuum is solved in a cylindrical coordinate system. It derives the cylindrical transverse electromagnetic wave mode in which the electric field and magnetic field are not in phase. Such electromagnetic wave can generate and exist in actual application, and there is no violation of the law of conservation of energy during the electromagnetic field interchanges.
SAR-ocean wave inversion using image cross spectra
Geir Engen; Harald Johnsen
Image cross-spectra obtained by combining pairs of single look SAR images are utilized in an inversion scheme for extracting the underlying ocean wave spectrum. The reasons for proposing the use of image cross-spectra instead of standard multilook spectra are twofold. First, the image cross-spectra are shown to significantly reduce the speckle noise level while preserving the spectral shape. Second, the
Absorption cross section and Hawking radiation of the electromagnetic field with Weyl corrections
Hao Liao; Songbai Chen; Jiliang Jing
We have investigated the absorption cross section and the Hawking radiation of electromagnetic field with Weyl correction in the background of a four-dimensional Schwarzschild black hole spacetime. Our results show that the properties of the absorption cross section and the Hawking radiation depend not only on the Weyl correction parameter, but also on the parity of the electromagnetic field, which is quite different from those of the usual electromagnetic field without Weyl correction in the four-dimensional spacetime. With increase of Weyl correction parameter, the absorption probability, the absorption cross section, the power emission spectra and the luminosity of Hawking radiation decreases with Weyl correction parameter for the odd-parity electromagnetic field and increases with the event-parity electromagnetic field.
Electromagnetically controllable osteoclast activity.
Hong, Jung Min; Kang, Kyung Shin; Yi, Hee-Gyeong; Kim, Shin-Yoon; Cho, Dong-Woo
The time-varying electromagnetic field (EMF) has been widely studied as one of the exogenous stimulation methods for improving bone healing. Our previous study showed that osteogenic differentiation of adipose-derived stem cells was accelerated by a 45-Hz EMF, whereas a 7.5-Hz EMF inhibited osteogenic marker expression. Accordingly, we hypothesized that each negative and positive condition for the osteogenic differentiation could inversely influence osteoclast formation and differentiation. Here, we demonstrated that osteoclast formation, differentiation, and activity can be regulated by altering the frequency of the electromagnetic stimulation, such as 7.5 (negative for osteogenic differentiation) and 45 Hz (positive for osteogenic differentiation). A 45 Hz EMF inhibited osteoclast formation whereas a 7.5-Hz EMF induced differentiation and activity. Osteoclastogenic markers, such as NFATc1, TRAP, CTSK, MMP9, and DC-STAMP were highly expressed under the 7.5-Hz EMF, while they were decreased at 45 Hz. We found that the 7.5-Hz EMF directly regulated osteoclast differentiation through ERK and p38 MAPK activation, whereas the EMF at 45 Hz suppressed RANKL-induced phosphorylation of I?B. Additionally, actin ring formation with tubules and bone resorptive activity were enhanced at 7.5 Hz through increased integrin ?3 expression. However, these were inhibited at 45 Hz. Although many questions remain unanswered, our study indicates that osteoclast formation and differentiation were controllable using physical tools, such as an EMF. It will now be of great interest to study the ill-defined correlation between electromagnetic conditions and osteoclast activities, which eventually could lead to determining the therapeutic characteristics of an EMF that will treat bone-related diseases. PMID:24556539
Electromagnetism on Anisotropic Fractals
Martin Ostoja-Starzewski
We derive basic equations of electromagnetic fields in fractal media which are specified by three indepedent fractal dimensions {\\alpha}_{i} in the respective directions x_{i} (i=1,2,3) of the Cartesian space in which the fractal is embedded. To grasp the generally anisotropic structure of a fractal, we employ the product measure, so that the global forms of governing equations may be cast in forms involving conventional (integer-order) integrals, while the local forms are expressed through partial differential equations with derivatives of integer order but containing coefficients involving the {\\alpha}_{i}'s. First, a formulation based on product measures is shown to satisfy the four basic identities of vector calculus. This allows a generalization of the Green-Gauss and Stokes theorems as well as the charge conservation equation on anisotropic fractals. Then, pursuing the conceptual approach, we derive the Faraday and Amp\\`ere laws for such fractal media, which, along with two auxiliary null-divergence conditions, effectively give the modified Maxwell equations. Proceeding on a separate track, we employ a variational principle for electromagnetic fields, appropriately adapted to fractal media, to independently derive the same forms of these two laws. It is next found that the parabolic (for a conducting medium) and the hyperbolic (for a dielectric medium) equations involve modified gradient operators, while the Poynting vector has the same form as in the non-fractal case. Finally, Maxwell's electromagnetic stress tensor is reformulated for fractal systems. In all the cases, the derived equations for fractal media depend explicitly on fractal dimensions and reduce to conventional forms for continuous media with Euclidean geometries upon setting the dimensions to integers.
Interpreting marine controlled source electromagnetic field behaviour with streamlines
NASA Astrophysics Data System (ADS)
Pethick, A. M.; Harris, B. D.
Streamlines represent particle motion within a vector field as a single line structure and have been used in many areas of geophysics. We extend the concept of streamlines to interactive three dimensional representations of the coupled vector fields generated during marine controlled source electromagnetic surveys. These vector fields have measurable amplitudes throughout many hundreds of cubic kilometres. Electromagnetic streamline representation makes electromagnetic interactions within complex geo-electrical setting comprehensible. We develop an interface to rapidly compute and interactively visualise the electric and magnetic fields as streamlines for 3D marine controlled source electromagnetic surveys. Several examples highlighting how interactive use has value in marine controlled source electromagnetic survey design, interpretation and teaching are provided. The first videos of electric, magnetic and Poynting vector field streamlines are provided along with the first published example of the airwave represented as streamlines. We demonstrate that the electric field airwave is a circulating vortex moving down and out from the air-water interface towards the ocean floor. The use of interactive streamlines is not limited to marine controlled source electromagnetic methods. Streamlines provides a high level visualisation tool for interpreting the electric and magnetic field behaviour generated by a wide range of electromagnetic survey configurations for complex 3D geo-electrical settings.
Advanced electromagnetic gun simulation
NASA Astrophysics Data System (ADS)
Brown, J. L.; George, E. B.; Lippert, J. R.; Balius, A. R.
The architecture, software and application of a simulation system for evaluating electromagnetic gun (EMG) operability, maintainability, test data and performance tradeoffs are described. The system features a generic preprocessor designed for handling the large data rates necessary for EMG simulations. The preprocessor and postprocessor operate independent of the EMG simulation, which is viewed through windows by the user, who can then select the areas of the simulation desired. The simulation considers a homopolar generator, busbars, pulse shaping coils, the barrel, switches, and prime movers. In particular, account is taken of barrel loading by the magnetic field, Lorentz force and plasma pressure.
Electromagnetic Probes in PHENIX
Gabor David
Electromagnetic probes are arguably the most universal tools to study the different physics processes in high energy hadron and heavy ion collisions. In this paper we summarize recent measurements of real and virtual direct photons at central rapidity by the PHENIX experiment at RHIC in p+p, d+Au and Au+Au collisions. We also discuss the impact of the results and the constraints they put on theoretical models. At the end we report on the immediate as well as on the mid-term future of photon measurements at RHIC.
Electromagnetic Meissner effect launcher
NASA Technical Reports Server (NTRS)
Robertson, Glen A. (inventor)
An electromagnetic projectile launcher provides acceleration of a superconducting projectile through the diamagnetic repulsion of the superconducting projectile. A superconducting layer is provided aft of the projectile, either directly on the projectile or on a platform upon which the projectile is carried, and a traveling magnetic field is caused to propagate along a magnetic field drive coil in which the projectile is disposed. The resulting diamagnetic repulsion between the superconducting projectile and the traveling magnetic field causes the projectile to be propelled along the coil. In one embodiment, a segmented drive coil is used to generate the traveling magnetic field.
Electromagnetic pump stator coil
Fanning, Alan W. (San Jose, CA); Dahl, Leslie R. (Livermore, CA)
An electrical stator coil for an electromagnetic pump includes a continuous conductor strip having first and second terminals at opposite ends thereof and an intermediate section disposed therebetween. The strip is configured in first and second coil halves, with the first coil half including a plurality of windings extending from the first terminal to the intermediate section, and the second coil half including a plurality of windings extending from the second terminal to the intermediate section. The first and second coil halves are disposed coaxially, and the first and second terminals are disposed radially inwardly therefrom with the intermediate section being disposed radially outwardly therefrom.
Electromagnetic pump stator coil
Fanning, A.W.; Dahl, L.R.
An electrical stator coil for an electromagnetic pump includes a continuous conductor strip having first and second terminals at opposite ends thereof and an intermediate section disposed therebetween. The strip is configured in first and second coil halves, with the first coil half including a plurality of windings extending from the first terminal to the intermediate section, and the second coil half including a plurality of windings extending from the second terminal to the intermediate section. The first and second coil halves are disposed coaxially, and the first and second terminals are disposed radially inwardly therefrom with the intermediate section being disposed radially outwardly therefrom. 9 figs.
The application of the high-frequency electromagnetic sounding method in the exploration of underground thermal water
Hui Cao; Lanfang He; Zhanxiang He; Xiaoming Zhao
High-frequency electromagnetic sounding is an electromagnetic exploration method using the natural high-frequency electromagnetic\\u000a field as a field source. It has higher resolution and greater depth penetration than the direct current method and is especially\\u000a fit for geothermal energy exploration and low-and mid-level groundwater detection. We introduce a successful application of\\u000a high-frequency electromagnetic sounding for evaluating geothermal water resources. The high
Power spectra of the interplanetary magnetic field
James W. Sari; Norman F. Ness
Power spectra based on Pioneer 6 interplanetary magnetic field data in early 1966 exhibit a frequency dependence of f-2 in the range 2.8 × 10-4 to 1.6 × 10-2 cps for periods of both quiet and disturbed field conditions. Both the shape and power levels of these spectra are found to be due to the presence of directional discontinuities in
Mathematical Tripos, Part IB : Electromagnetism 4 Electromagnetic induction
Mathematical Tripos, Part IB : Electromagnetism 4 Electromagnetic induction Recall the paragraph's theorem to a fixed curve C = S bounding a fixed open surface S. If we define the electromotive force (orS, (3) then we get Faraday's Law of induction E = - d dt . (4) This will be studied now. In chapter two
Acute bioeffects of electromagnetic lithotripsy.
Atahan, O; Alkibay, T; Karao?lan, U; Deniz, N; Bozkirli, I
Acute effects of extracorporeal shock wave lithotripsy (ESWL) with Siemens Lithostar on kidney and surrounding tissues were examined on 42 patients with unilateral kidney stones in the Department of Urology, Gazi University, Medical Faculty, Ankara, Türkiye. Radiological examinations were done and 24-h urine and blood samples were obtained a day before, the day after and 30 days after ESWL. Urinary excretion of proteins, glycosaminoglycan, and immunoglobulin G were significantly elevated the day after ESWL. Thirty days after excretion levels of these were statistically insignificant in regard to pretreatment levels. Creatinine clearance of the patients was significantly lowered the day after ESWL. One month later differences were insignificant. Excretory urography detected 12 (29%) kidneys with abnormalities the day after ESWL. Thirty days after only 3 (7%) of the kidneys had persistent abnormalities. The number of abnormalities with ultrasonography 24 h and 30 days after ESWL were 15 (36%) and 5 (12%) respectively. With CT-scanning kidney abnormalities 24 h after and 30 days after ESWL were 24 (57%) and 6 (14%) respectively. There was not any statistically significant difference between patients with either radiological or functional changes after ESWL and with patients without these changes in regard to patient age, sex, stone burden and shock wave number. In conclusion, electromagnetic lithotripsy induces acute renal morphologic and functional changes. Functional changes are transient and subside within a month but although decreasing either in size or number some morphologic changes persist during this period. PMID:8908646
Metamaterials beyond electromagnetism.
Kadic, Muamer; Bückmann, Tiemo; Schittny, Robert; Wegener, Martin
Metamaterials are rationally designed man-made structures composed of functional building blocks that are densely packed into an effective (crystalline) material. While metamaterials are mostly associated with negative refractive indices and invisibility cloaking in electromagnetism or optics, the deceptively simple metamaterial concept also applies to rather different areas such as thermodynamics, classical mechanics (including elastostatics, acoustics, fluid dynamics and elastodynamics), and, in principle, also to quantum mechanics. We review the basic concepts, analogies and differences to electromagnetism, and give an overview on the current state of the art regarding theory and experiment-all from the viewpoint of an experimentalist. This review includes homogeneous metamaterials as well as intentionally inhomogeneous metamaterial architectures designed by coordinate-transformation-based approaches analogous to transformation optics. Examples are laminates, transient thermal cloaks, thermal concentrators and inverters, 'space-coiling' metamaterials, anisotropic acoustic metamaterials, acoustic free-space and carpet cloaks, cloaks for gravitational surface waves, auxetic mechanical metamaterials, pentamode metamaterials ('meta-liquids'), mechanical metamaterials with negative dynamic mass density, negative dynamic bulk modulus, or negative phase velocity, seismic metamaterials, cloaks for flexural waves in thin plates and three-dimensional elastostatic cloaks. PMID:24190877
Metamaterials beyond electromagnetism
NASA Astrophysics Data System (ADS)
Kadic, Muamer; Bückmann, Tiemo; Schittny, Robert; Wegener, Martin
Metamaterials are rationally designed man-made structures composed of functional building blocks that are densely packed into an effective (crystalline) material. While metamaterials are mostly associated with negative refractive indices and invisibility cloaking in electromagnetism or optics, the deceptively simple metamaterial concept also applies to rather different areas such as thermodynamics, classical mechanics (including elastostatics, acoustics, fluid dynamics and elastodynamics), and, in principle, also to quantum mechanics. We review the basic concepts, analogies and differences to electromagnetism, and give an overview on the current state of the art regarding theory and experiment—all from the viewpoint of an experimentalist. This review includes homogeneous metamaterials as well as intentionally inhomogeneous metamaterial architectures designed by coordinate-transformation-based approaches analogous to transformation optics. Examples are laminates, transient thermal cloaks, thermal concentrators and inverters, 'space-coiling' metamaterials, anisotropic acoustic metamaterials, acoustic free-space and carpet cloaks, cloaks for gravitational surface waves, auxetic mechanical metamaterials, pentamode metamaterials ('meta-liquids'), mechanical metamaterials with negative dynamic mass density, negative dynamic bulk modulus, or negative phase velocity, seismic metamaterials, cloaks for flexural waves in thin plates and three-dimensional elastostatic cloaks.
Localization of Classical Waves II: Electromagnetic Waves.
Localization of Classical Waves II: Electromagnetic Waves. Alexander Figotin \\Lambda Department We consider electromagnetic waves in a medium described by a position dependent dielectric constant at all times. Localization of electromagnetic waves is a consequence of Anderson localization
NSDL National Science Digital Library
This resource explains why we go to the expense of launching satellites to gather spectral data in space. The earth's atmosphere does not allow light of all wavelengths to pass through it. In order to see gamma, X ray, ultraviolet (UV), infrared, and microwave radiation, we must place telescopes and other light-gathering instruments above the atmosphere. At this site, students investigate satellite missions operating in four electromagnetic bands using the internet and hands-on activities. After successfully completing these activities, students will be able to identify four different regions of the electromagnetic spectrum and order them by wavelength, describe one or more of the four satellite missions featured in the site, its capabilities, and some objects it is used to observe, and conduct and draw appropriate conclusions from some or all of four hands-on activities.
Electromagnetic radiation from beam-plasma instabilities
NASA Technical Reports Server (NTRS)
Pritchett, P. L.; Dawson, J. M.
A computer simulation is developed for the generation of electromagnetic radiation in an electron beam-plasma interaction. The plasma is treated as a two-dimensional finite system, and effects of a continuous nonrelativistic beam input are accounted for. Three momentum and three field components are included in the simulation, and an external magnetic field is excluded. EM radiation generation is possible through interaction among Langmuir oscillations, ion-acoustic waves, and the electromagnetic wave, producing radiation perpendicular to the beam. The radiation is located near the plasma frequency, and polarized with the E component parallel to the beam. The scattering of Langmuir waves caused by ion-acoustic fluctuations generates the radiation. Comparison with laboratory data for the three-wave interactions shows good agreement in terms of the radiation levels produced, which are small relative to the plasma thermal energy.
Coherent spin control by electromagnetic vacuum fluctuations
Wang Jing [Department of Physics, Chinese University of Hong Kong, Shatin, N.T. (Hong Kong); Department of Physics, Tsinghua University, Beijing 100084 (China); Liu Renbao [Department of Physics, Chinese University of Hong Kong, Shatin, N.T. (Hong Kong); Zhu Bangfen [Department of Physics, Tsinghua University, Beijing 100084 (China); Institute of Advanced Study, Tsinghua University, Beijing 100084 (China); Sham, L. J. [Department of Physics, University of California-San Diego, La Jolla, California 92093-0319 (United States); Steel, D. G. [H. M. Randall Laboratory of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)
In coherent control, electromagnetic vacuum fluctuations usually cause coherence loss through irreversible spontaneous emission. However, since the dissipation via emission is essentially due to correlation of the fluctuations, when emission ends in a superposition of multiple final states, correlation between different pathways may build up if the 'which way' information is not fully resolved (i.e., the emission spectrum is broader than the transition energy range). Such correlation can be exploited for spin-flip control in a {Lambda}-type three-level system, which manifests itself as an all-optical spin echo in nonlinear optics with two orders of optical fields saved as compared with stimulated Raman processes. This finding represents a class of optical nonlinearity induced by electromagnetic vacuum fluctuations.
ERIC Educational Resources Information Center
Electromagnetic neutrino: a short review
Alexander I. Studenikin
A short review on selected issues related to the problem of neutrino electromagnetic properties is given. After a flash look at the theoretical basis of neutrino electromagnetic form factors, constraints on neutrino magnetic moments and electric millicharge from terrestrial experiments and astrophysical observations are discussed. We also focus on some recent studies of the problem and on perspectives.
Particle swarm optimization in electromagnetics
Jacob Robinson; Yahya Rahmat-Samii
The particle swarm optimization (PSO), new to the electromagnetics community, is a robust stochastic evolutionary computation technique based on the movement and intelligence of swarms. This paper introduces a conceptual overview and detailed explanation of the PSO algorithm, as well as how it can be used for electromagnetic optimizations. This paper also presents several results illustrating the swarm behavior in
Exploration of the Electromagnetic Environment
ERIC Educational Resources Information Center
Fullekrug, M.
The electromagnetic environment is composed of electric and magnetic fields which result from man-made and natural sources. An elementary experiment is described to explore the electromagnetic environment by measuring electric fields in the frequency range from approximately equal to 10 to 24 000 Hz. The equipment required to conduct the…
Electromagnetic self interaction in strings
Brandon Carter
To facilitate the treatment of electromagnetic effects in applications such as dynamically perturbed vortons, this work employs a covariantly formulated string-source Green measure to obtain a coherent relativistic scheme for describing the self interaction of electromagnetic currents in string models of a very general kind, at leading order in the relevant field gradients, using a regularised gradient operator given by $\\hat\
Electromagnetics laboratory annual report, 1994
I. V. Lindell; A. H. Sihvola
Activities of the Electromagnetics Laboratory during 1994 are described in this report. As highlights of the output stand the monographs Electromagnetic Waves in Chiral and Bi-Isotropic Media (Artech House, Boston) and History of Electrical Engineering (Otatieto, Espoo, in Finnish). Also, the total number of papers published and accepted for publication in international refereed journals show a new record, 40 items.
Electromagnetic energy around Hertzian dipoles
Hans Gregory Schantz
This paper considers the behavior of electromagnetic energy around Hertzian dipoles. The method of "causal surfaces" (surfaces through which there is no net flow of electromagnetic energy) is used to partition and track the energy. A variety of examples, involving both transient and harmonic time dependence, are presented, to illustrate the way in which static and\\/or reactive energy is converted
Transmitting Electromagnetic Energy into Liquids
NASA Technical Reports Server (NTRS)
Johnston, E. J.
Rough liquid surface enhances coupling. Agitating surface of liquid nitrogen bath with periodic or aperiodic excitation enhances electromagnetic coupling between microwave horn and blackbody temperature standard immersed in liquid. Useful in interfaces between electromagnetic radiation and liquids. Biomedical, radar, and meteorological applications.
The CLAS Forward Electromagnetic Calorimeter
Thomas Jefferson National Accelerator Facility
The CLAS Forward Electromagnetic Calorimeter M. Amarian d , G. Asryan d , K. Beard b , W. Brooks ) of each sector is equipped with a lead-scintillator electromagnetic sampling calorimeter (EC), 16 radiation lengths thick, using a novel triangular geometry with stereo readout. With its good energy
Electromagnetism IB Dr Natalia Berloff
Electromagnetism IB Dr Natalia Berloff Summary of Vector Calculus The following results apply to any (suitably differentiable) scalar field (x) and vector fields E(x) and B(x). They all have important applications in electromagnetism. Derivatives of a vector field: div E ·E = Ei xi has one
Torsion as electromagnetism and spin
Nikodem J. Poplawski
We show that it is possible to formulate the classical Einstein-Maxwell-Dirac theory of spinors interacting with the gravitational and electromagnetic fields as the Einstein-Cartan-Kibble-Sciama theory with the Ricci scalar of the traceless torsion, describing gravity, and the torsion trace acting as the electromagnetic potential.
Numerical calculation of electromagnetic actuators
B. Aldefeld
Contents The paper describes a numerical method of calculating the magnetic fields, forces, inductances, and the dynamic behaviour of electromagnetic actuators. The solution of the non-linear partial differential equation for the magnetic vector potential is obtained by finite difference techniques using line iteration and acceleration of convergence. Examples of application are given for an electromagnetic print needle actuator.
Gravitational scattering of electromagnetic radiation
NASA Technical Reports Server (NTRS)
Brooker, J. T.; Janis, A. I.
The scattering of electromagnetic radiation by linearized gravitational fields is studied to second order in a perturbation expansion. The incoming electromagnetic radiation can be of arbitrary multipole structure, and the gravitational fields are also taken to be advanced fields of arbitrary multipole structure. All electromagnetic multipole radiation is found to be scattered by gravitational monopole and time-varying dipole fields. No case has been found, however, in which any electromagnetic multipole radiation is scattered by gravitational fields of quadrupole or higher-order multipole structure. This lack of scattering is established for infinite classes of special cases, and is conjectured to hold in general. The results of the scattering analysis are applied to the case of electromagnetic radiation scattered by a moving mass. It is shown how the mass and velocity may be determined by a knowledge of the incident and scattered radiation.
NASA Astrophysics Data System (ADS)
Allamandola, Louis; Bauschlicher, Charlie, Jr.; Mattioda, Andrew
The Ames Astrochemistry Laboratory now has PAH IR spectra of more than 220 laboratory measured and over 600 theoretically calculated IR spectra of polycyclic aromatic hydrocarbons (PAHs) in a multitude of forms. The vast majority of these spectra are not readily accessible to the public. We propose to make the full collection of the Ames experimental and computational collection of PAH IR spectra available to the entire Spitzer community and accessible via the World Wide Web (WWW). The laboratory measured mid-IR spectral collection includes over 220 neutral, cationic, and anionic PAHs, PAHs with deuterium in place of hydrogen, PAHs containing oxygen, and PAHs containing nitrogen (PANHs). The formulae of the PAHs in the experimental data collection range from C10H8 to C50H22. Unfortunately, it is not possible to obtain physical samples of all of the types of PAHs that are of astrophysical interest for experimental study. We also have an extensive collection of accurate computational spectra to fill in gaps in the experimentally available spectra. Our theoretical PAH spectral collection includes very large PAHs, PAHs containing 40 to 132 carbon atoms which are comparable to the size of the PAHs thought to dominate the interstellar emission spectrum. Large PAHs might be multiply charged and these are also represented in the theoretical database. There is also observational evidence for PAH cations with nitrogen in the inner rings (PANHs) and interest in the spectroscopy of aromatic species containing oxygen and deuterium as well as PAH metal clusters. All of these types of PAHs are represented in the Ames computational PAH IR spectroscopic collection. If funded, we plan to make our entire inventory of the lab spectra available to the Spitzer community within the next two years.
Electromagnetic cascades in pulsars
NASA Technical Reports Server (NTRS)
Daugherty, J. K.; Harding, A. K.
The development of pair photon cascades initiated by high energy electrons above a pulsar polar cap is simulated numerically. The calculation uses the energy of the primary electron, the magnetic field strength, and the period of rotation as parameters and follows the curvature radiation emitted by the primary, the conversion of this radiation e(+) - e(-) pairs in the intense fields, and the quantized synchrotron radiation by the secondary pairs. A recursive technique allows the tracing of an indefinite number of generations using a Monte Carlo method. Gamma ray and pair spectra are calculated for cascades in different parts of the polar cap and with different acceleration models. It is found that synchrotron radiation from secondary pairs makes an important contribution to the gamma ray spectrum above 25 MeV, and that the final gamma ray and pair spectra are insensitive to the height of the accelerating region, as long as the acceleration of the primary electrons is not limited by radiation reaction.
Electromagnetic Radiation (Light)
NSDL National Science Digital Library
Strobel, Nick
Authored by Nick Strobel, "Astronomy Notes" is an educational resource for introductory astronomy classes for undergraduates. This section describes general properties of light, frequency, the spectrum, and temperature. Other topics include: light production, continuous spectra, emission lines, absorption lines and the Bohr model for the atom. There is also an explanation of the Doppler Effect and why spectral lines are used to measure doppler shifts.
Nucleon Electromagnetic Form Factors
Marc Vanderhaeghen; Charles Perdrisat; Vina Punjabi
There has been much activity in the measurement of the elastic electromagnetic proton and neutron form factors in the last decade, and the quality of the data has greatly improved by performing double polarization experiments, in comparison with previous unpolarized data. Here we review the experimental data base in view of the new results for the proton, and neutron, obtained at JLab, MAMI, and MIT-Bates. The rapid evolution of phenomenological models triggered by these high-precision experiments will be discussed, including the recent progress in the determination of the valence quark generalized parton distributions of the nucleon, as well as the steady rate of improvements made in the lattice QCD calculations.
Causal electromagnetic interaction equations
Zinoviev, Yury M. [Steklov Mathematical Institute, Gubkin Street 8, 119991, Moscow (Russian Federation)
For the electromagnetic interaction of two particles the relativistic causal quantum mechanics equations are proposed. These equations are solved for the case when the second particle moves freely. The initial wave functions are supposed to be smooth and rapidly decreasing at the infinity. This condition is important for the convergence of the integrals similar to the integrals of quantum electrodynamics. We also consider the singular initial wave functions in the particular case when the second particle mass is equal to zero. The discrete energy spectrum of the first particle wave function is defined by the initial wave function of the free-moving second particle. Choosing the initial wave functions of the free-moving second particle it is possible to obtain a practically arbitrary discrete energy spectrum.
The Electromagnetic Code Consortium
NASA Astrophysics Data System (ADS)
Faison, Joseph C.
A decision was made in 1987 to consolidate radar cross section (RCS) code development sponsored by the U.S. armed services and NASA. An RCS code consortium was formed, consisting of a government steering group and members from the industrial/academic community. Since the formation of the consortium, significant progress has been made to advance code development work sponsored by the U.S. government. This paper is intended to make the RCS community aware of the Electromagnetic Code Consortium, so that potential contributors to code development can become involved with its work. It covers the approach taken by the consortium, the acquisition of a government-owned geometry code, validation, language and documentation, the support contractor, a survey of industry codes, and benchmarking.
Pulsed electromagnetic gas acceleration
NASA Technical Reports Server (NTRS)
Jahn, R. G.; Vonjaskowsky, W. F.; Clark, K. E.
Experimental data were combined with one-dimensional conservation relations to yield information on the energy deposition ratio in a parallel-plate accelerator, where the downstream flow was confined to a constant area channel. Approximately 70% of the total input power was detected in the exhaust flow, of which only about 20% appeared as directed kinetic energy, thus implying that a downstream expansion to convert chamber enthalpy into kinetic energy must be an important aspect of conventional high power MPD arcs. Spectroscopic experiments on a quasi-steady MPD argon accelerator verified the presence of A(III) and the absence of A(I), and indicated an azimuthal structure in the jet related to the mass injection locations. Measurements of pressure in the arc chamber and impact pressure in the exhaust jet using a piezocrystal backed by a Plexiglas rod were in good agreement with the electromagnetic thrust model.
Computational electronics and electromagnetics
Shang, C. C.
The Computational Electronics and Electromagnetics thrust area at Lawrence Livermore National Laboratory serves as the focal point for engineering R&D activities for developing computer-based design, analysis, and tools for theory. Key representative applications include design of particle accelerator cells and beamline components; engineering analysis and design of high-power components, photonics, and optoelectronics circuit design; EMI susceptibility analysis; and antenna synthesis. The FY-96 technology-base effort focused code development on (1) accelerator design codes; (2) 3-D massively parallel, object-oriented time-domain EM codes; (3) material models; (4) coupling and application of engineering tools for analysis and design of high-power components; (5) 3-D spectral-domain CEM tools; and (6) enhancement of laser drilling codes. Joint efforts with the Power Conversion Technologies thrust area include development of antenna systems for compact, high-performance radar, in addition to novel, compact Marx generators. 18 refs., 25 figs., 1 tab.
Superconducting electromagnetic thruster
Meng, J.
An electromagnetic thruster for marine vehicles using a jet of water driven by the interaction of a mutually perpendicular intensified magnetic field and an intensified electric field is disclosed. The intensified magnetic field is produced by superconducting coils cooled by a coolant such as liquid helium. An intensified electric field is produced by passing high amperage current across the seawater jet. These interacting fields produce a Lorentz force perpendicular to mutually perpendicular electric and magnetic field vectors which is used to drive the seawater jet. In some embodiments, the force may also be used to draw water into the jet from the boundary layer flow around the vehicle thereby reducing boundary layer turbulence and associated radiated noise.
Electromagnetic scattering theory
NASA Technical Reports Server (NTRS)
Bird, J. F.; Farrell, R. A.
Electromagnetic scattering theory is discussed with emphasis on the general stochastic variational principle (SVP) and its applications. The stochastic version of the Schwinger-type variational principle is presented, and explicit expressions for its integrals are considered. Results are summarized for scalar wave scattering from a classic rough-surface model and for vector wave scattering from a random dielectric-body model. Also considered are the selection of trial functions and the variational improvement of the Kirchhoff short-wave approximation appropriate to large size-parameters. Other applications of vector field theory discussed include a general vision theory and the analysis of hydromagnetism induced by ocean motion across the geomagnetic field. Levitational force-torque in the magnetic suspension of the disturbance compensation system (DISCOS), now deployed in NOVA satellites, is also analyzed using the developed theory.
Electromagnetically Clean Solar Arrays
NASA Technical Reports Server (NTRS)
Stem, Theodore G.; Kenniston, Anthony E.
The term 'electromagnetically clean solar array' ('EMCSA') refers to a panel that contains a planar array of solar photovoltaic cells and that, in comparison with a functionally equivalent solar-array panel of a type heretofore used on spacecraft, (1) exhibits less electromagnetic interferences to and from other nearby electrical and electronic equipment and (2) can be manufactured at lower cost. The reduction of electromagnetic interferences is effected through a combination of (1) electrically conductive, electrically grounded shielding and (2) reduction of areas of current loops (in order to reduce magnetic moments). The reduction of cost is effected by designing the array to be fabricated as a more nearly unitary structure, using fewer components and fewer process steps. Although EMCSAs were conceived primarily for use on spacecraft they are also potentially advantageous for terrestrial applications in which there are requirements to limit electromagnetic interference. In a conventional solar panel of the type meant to be supplanted by an EMCSA panel, the wiring is normally located on the back side, separated from the cells, thereby giving rise to current loops having significant areas and, consequently, significant magnetic moments. Current-loop geometries are chosen in an effort to balance opposing magnetic moments to limit far-0field magnetic interactions, but the relatively large distances separating current loops makes full cancellation of magnetic fields problematic. The panel is assembled from bare photovoltaic cells by means of multiple sensitive process steps that contribute significantly to cost, especially if electomagnetic cleanliness is desired. The steps include applying a cover glass and electrical-interconnect-cell (CIC) sub-assemble, connecting the CIC subassemblies into strings of series-connected cells, laying down and adhesively bonding the strings onto a panel structure that has been made in a separate multi-step process, and mounting the wiring on the back of the panel. Each step increases the potential for occurrence of latent defects, loss of process control, and attrition of components. An EMCSA panel includes an integral cover made from a transparent material. The silicone cover supplants the individual cover glasses on the cells and serves as an additional unitary structural support that offers the advantage, relative to glass, of the robust, forgiving nature of the silcone material. The cover contains pockets that hold the solar cells in place during the lamination process. The cover is coated with indium tin oxide to make its surface electrically conductive, so that it serves as a contiguous, electrically grounded shield over the entire panel surface. The cells are mounted in proximity to metallic printed wiring. The painted-wiring layer comprises metal-film traces on a sheet of Kapton (or equivalent) polyimide. The traces include contact pads on one side of the sheet for interconnecting the cells. Return leads are on the opposite side of the sheet, positioned to form the return currents substantially as mirror images of, and in proximity to, the cell sheet currents, thereby minimizing magnetic moments. The printed-wiring arrangement mimics the back-wiring arrangement of conventional solar arrays, but the current-loop areas and the resulting magnetic moments are much smaller because the return-current paths are much closer to the solar-cell sheet currents. The contact pads are prepared with solder fo electrical and mechanical bonding to the cells. The pocketed cover/shield, the solar cells, the printed-wiring layer, an electrical bonding agent, a mechanical-bonding agent, a composite structural front-side face sheet, an aluminum honeycomb core, and a composite back-side face sheet are all assembled, then contact pads are soldered to the cells and the agents are cured in a single lamination process.
NSDL National Science Digital Library
In this lesson, students are introduced to the electromagnetic spectrum. They observe a demonstration of the visible light spectrum created by a flashlight and a prism, complete an activity sheet where they identify the wavelength that is involved in technologies used in their communities, and learn about satellite sensors that remotely sense data. Student worksheets, a data sheet, answer keys, and Web links are included. This is Lesson 3 in Understanding Light, part of IMAGERS, Interactive Media Adventures for Grade School Education using Remote Sensing. The website provides hands-on activities in the classroom supporting the science content in two interactive media books, The Adventures of Echo the Bat and Amelia the Pigeon.
Inelastic processes and interference effects during the interaction of positronium with ultrashort electromagnetic pulses
Eseev, M. K., E-mail: firstname.lastname@example.com; Matveev, V. I., E-mail: email@example.com [Lomonosov Northern (Arctic) Federal University (Russian Federation)
The excitation, breakup, and reradiation during the interaction of a positronium atom with ultrashort electromagnetic pulses are considered. The probabilities of inelastic processes and reradiation spectra have been obtained. The interference between the amplitudes of the photon emission by the electron and positron is shown to contribute noticeably to the reradiation spectra. The developed approach is applicable for describing the interaction of positronium with ultrashort pulses of attosecond or shorter duration.
Comparison between electroglottography and electromagnetic glottography
Titze, Ingo R. [Department of Speech Pathology and Audiology and National Center for Voice and Speech, The University of Iowa and the Denver Center for the Performing Arts, Iowa City, Iowa 52242 (United States)] [Department of Speech Pathology and Audiology and National Center for Voice and Speech, The University of Iowa and the Denver Center for the Performing Arts, Iowa City, Iowa 52242 (United States); Story, Brad H. [Department of Speech Pathology and Audiology and National Center for Voice and Speech, The University of Iowa and the Denver Center for the Performing Arts, Iowa City, Iowa 52242 (United States)] [Department of Speech Pathology and Audiology and National Center for Voice and Speech, The University of Iowa and the Denver Center for the Performing Arts, Iowa City, Iowa 52242 (United States); Burnett, Gregory C. [Department of Applied Science, University of California at Davis, and Lawrence Livermore National Laboratory, Livermore, California 94557 (United States)] [Department of Applied Science, University of California at Davis, and Lawrence Livermore National Laboratory, Livermore, California 94557 (United States); Holzrichter, John F. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)] [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Ng, Lawrence C. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)] [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Lea, Wayne A. [Speech Sciences Institute, Apple Valley, Minnesota 55124 (United States)] [Speech Sciences Institute, Apple Valley, Minnesota 55124 (United States)
Newly developed glottographic sensors, utilizing high-frequency propagating electromagnetic waves, were compared to a well-established electroglottographic device. The comparison was made on four male subjects under different phonation conditions, including three levels of vocal fold adduction (normal, breathy, and pressed), three different registers (falsetto, chest, and fry), and two different pitches. Agreement between the sensors was always found for the glottal closure event, but for the general wave shape the agreement was better for falsetto and breathy voice than for pressed voice and vocal fry. Differences are attributed to the field patterns of the devices. Whereas the electroglottographic device can operate only in a conduction mode, the electromagnetic device can operate in either the forward scattering (diffraction) mode or in the backward scattering (reflection) mode. Results of our tests favor the diffraction mode because a more favorable angle imposed on receiving the scattered (reflected) signal did not improve the signal strength. Several observations are made on the uses of the electromagnetic sensors for operation without skin contact and possibly in an array configuration for improved spatial resolution within the glottis. (c) 2000 Acoustical Society of America.
Nonlinear evolution of electromagnetic ion cyclotron waves
Silin, I.; Sydora, R. D.; Mann, I. R.; Sauer, K. [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2G7 (Canada); Mace, R. L. [School of Physics, University of KwaZulu-Natal, Durban 4000 (South Africa)
Hybrid Vlasov-Fourier modeling is used to investigate the nonlinear evolution of electromagnetic ion cyclotron (EMIC) waves driven by proton temperature anisotropy in plasmas with a population of He{sup +} ions and a cold proton background. In the pure proton-electron plasma, most of the free energy is converted into high-amplitude waves and currents. In the nonlinear stage, within a few hundred proton gyroperiods after the saturation, the wave spectrum shifts toward lower wave numbers and frequencies, from {omega}{approx}0.6{Omega}{sub p} to below {omega}{approx}0.25{Omega}{sub p}. In the presence of even a small population of He{sup +} ions almost all of the free energy is used in He{sup +} heating. The wave activity in the saturated state moves from the linearly unstable upper branch to the linearly stable lower one. In the presence of a background of cold protons, the waves can propagate in the frequency stop-band. Our results demonstrate that linear stability theory cannot be used to estimate the characteristics of the expected saturated wave spectra in the terrestrial magnetosphere. Significantly, our nonlinear simulations produce wave spectra which are in close agreement with the EMIC waves observed in situ by satellites as well as by ground-based magnetometers positioned at the ends of the magnetic field lines.
Bobbing and kicks in electromagnetism and gravity
Gralla, Samuel E.; Harte, Abraham I.; Wald, Robert M. [Enrico Fermi Institute and Department of Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637 (United States)
We study systems analogous to binary black holes with spin in order to gain some insight into the origin and nature of 'bobbing' motion and 'kicks' that occur in this system. Our basic tool is a general formalism for describing the motion of extended test bodies in an external electromagnetic field in curved spacetime and possibly subject to other forces. We first show that bobbing of exactly the type as observed in numerical simulations of the binary black hole system occurs in a simple system consisting of two spinning balls connected by an elastic band in flat spacetime. This bobbing may be understood as arising from the difference between a spinning body's 'lab frame centroid' and its true center of mass, and is purely 'kinematical' in the sense that it will appear regardless of the forces holding two spinning bodies in orbit. Next, we develop precise rules for relating the motion of charged bodies in a stationary external electromagnetic field in flat spacetime with the motion of bodies in a weakly curved stationary spacetime. We then consider the system consisting of two orbiting charges with magnetic dipole moment and spin at a level of approximation corresponding to 1.5 post-Newtonian order. Here we find that considerable amounts of momentum are exchanged between the bodies and the electromagnetic field; however, the bodies store this momentum entirely as ''hidden'' mechanical momentum, so that the interchange does not give rise to any net bobbing. The net bobbing that does occur is due solely to the kinematical spin effect, and we therefore argue that the net bobbing of the electromagnetic binary is not associated with possible kicks. We believe that this conclusion holds in the gravitational case as well.
Bobbing and kicks in electromagnetism and gravity
NASA Astrophysics Data System (ADS)
Gralla, Samuel E.; Harte, Abraham I.; Wald, Robert M.
We study systems analogous to binary black holes with spin in order to gain some insight into the origin and nature of "bobbing" motion and "kicks" that occur in this system. Our basic tool is a general formalism for describing the motion of extended test bodies in an external electromagnetic field in curved spacetime and possibly subject to other forces. We first show that bobbing of exactly the type as observed in numerical simulations of the binary black hole system occurs in a simple system consisting of two spinning balls connected by an elastic band in flat spacetime. This bobbing may be understood as arising from the difference between a spinning body's "lab frame centroid" and its true center of mass, and is purely "kinematical" in the sense that it will appear regardless of the forces holding two spinning bodies in orbit. Next, we develop precise rules for relating the motion of charged bodies in a stationary external electromagnetic field in flat spacetime with the motion of bodies in a weakly curved stationary spacetime. We then consider the system consisting of two orbiting charges with magnetic dipole moment and spin at a level of approximation corresponding to 1.5 post-Newtonian order. Here we find that considerable amounts of momentum are exchanged between the bodies and the electromagnetic field; however, the bodies store this momentum entirely as "hidden" mechanical momentum, so that the interchange does not give rise to any net bobbing. The net bobbing that does occur is due solely to the kinematical spin effect, and we therefore argue that the net bobbing of the electromagnetic binary is not associated with possible kicks. We believe that this conclusion holds in the gravitational case as well.
Cam McLeman; Erin McNicholas
We introduce a new invariant, the coronal of a graph, and use it to compute the spectrum of the corona G?H of two graphs G and H. In particular, we show that this spectrum is completely determined by the spectra of G and H and the coronal of H. Previous work has computed the spectrum of a corona only in
PHYSICS 417. Electromagnetism. Lecturer: Tim Gorringe.
MacAdam, Keith
PHYSICS 417. Electromagnetism. Lecturer: Tim Gorringe. Office: CP273. Phone: 257-8740. Textbook: Electromagnetic Fields, R. Wangsness, 2nd Ed. Web page www.pa.uky.edu/gorringe/phy417/index.html Class hours: MWF-semester sequence on electromagnetic theory. 1 Course Objectives. The electromagnetic field binds electrons
Phase-space representation of electromagnetic radiometry
Roman Castaneda
The phase-space representation of electromagnetic radiometry is founded on the electromagnetic generalized radiance tensors, which allow overcoming the limitations due to the scalar electromagnetic generalized radiances. The fundamental quantities of both scalar generalized radiometry and classical radiometry or photometry become particular cases. The transport of measurable radiometric quantities by the electromagnetic field is described in terms of the propagation of
Natural electromagnetic ULF noise due to fluctuations of ionospheric currents
NASA Astrophysics Data System (ADS)
Surkov, V. V.; Hayakawa, M.
An origin of natural electromagnetic noise observed on the ground surface in the frequency range 10-4-10-2 Hz was examined. Following a recent paper by Surkov and Hayakawa (2007), a flicker noise or 1/f noise, provided by random currents, is treated as a possible source of the ULF electromagnetic noise. In contrast to the cited paper, MHD wave incident on the ionosphere and neutral gas flow in the altitude range of conducting E layer of the ionosphere are considered to be a candidate mechanism for random current fluctuations, which in turn produce random electromagnetic fluctuations in the atmosphere. The main emphasis is on the flicker noise provided by the wind-driven ionospheric currents, which is assumed to be steady, uniform, and isotropic random fields inside the ionosphere. A correlation radius of random ionospheric fields is supposed to be controlled by neutral gas transfer and by acoustic/gravity wave propagation inside the E layer. A correlation matrix and power spectra of the random electromagnetic fields on the ground surface were calculated. The predicted spectral index of the power spectrum of the ULF magnetic noise was found to be 3, which is consistent with ground-based observations. The experimental data were demonstrated to be sandwiched between two theoretical lines, which correspond to daytime and nighttime ionospheric parameters.
Structures in the cosmic ray energy spectra
Erlykin, Anatoly
All the components of cosmic rays have 'structure' in their energy spectra at some level, ie deviations from a simple power law, and their examination is relevant to the origin of the particles. Emphasis, here, is placed on the large-scale structures in the spectra of nuclei (the 'knee' at about 3 PeV), that of electrons and positrons (a shallow 'upturn' at about 100 GeV) and the positron to electron plus positron ratio (an upturn starting at about 5 GeV). Fine structure is defined as deviations from the smooth spectra which already allow for the large-scale structure. Search for the fine structure has been performed in the precise data on positron to electron plus positron ratio measured by the AMS-02 experiment. Although no fine structure is indicated, it could in fact be present at the few percent level.
Electromagnetic metamaterials: Simplicity unlocks complexity
NASA Astrophysics Data System (ADS)
Dal Negro, Luca
By carefully selecting only two elemental 'building block materials' at the nanoscale, it is possible to digitally design composite electromagnetic media with properties vastly different from their individual constituents and suitable for performing complex optical functions.
Electromagnetic Dissociation and Space Radiation
John W. Norbury; Khin Maung Maung
Relativistic nucleus-nucleus reactions occur mainly through the Strong or Electromagnetic (EM) interactions. Transport codes often neglect the latter. This work shows the importance of including EM interactions for space radiation applications.
Conical electromagnetic radiation flux concentrator
NASA Technical Reports Server (NTRS)
Miller, E. R.
Concentrator provides method of concentrating a beam of electromagnetic radiation into a smaller beam, presenting a higher flux density. Smaller beam may be made larger by sending radiation through the device in the reverse direction.
Electromagnetic Showers at High Energy
ERIC Educational Resources Information Center
Loos, J. S.; Dawson, S. L.
Some of the properties of electromagnetic showers observed in an experimental study are illustrated. Experimental data and results from quantum electrodynamics are discussed. Data and theory are compared using computer simulation. (BB)
Photoreflectance spectra of excitonic polaritons in GaN substrate prepared by lateral epitaxial overgrowth
S. F. Chichibu; K. Torii; T. Deguchi; T. Sota; A. Setoguchi; H. Nakanishi; T. Azuhata; S. Nakamura
Photoreflectance (PR) spectra of high-purity, nearly free-standing GaN substrate were compared with emission and reflectance spectra, which were analyzed based on a model exciton-polariton picture in which A, B, and C free excitons couple simultaneously to an electromagnetic wave. The GaN substrate with reduced dislocation density was prepared by lateral epitaxial overgrowth technique and it exhibited predominant excitonic emissions with
Black Hole Thermodynamics and Electromagnetism
Burra G. Sidharth
We show a strong parallel between the Hawking, Beckenstein black hole Thermodynamics and electromagnetism: When the gravitational coupling constant transform into the electromagnetic coupling constant, the Schwarzchild radius, the Beckenstein temperature, the Beckenstein decay time and the Planck mass transform to respectively the Compton wavelength, the Hagedorn temperature, the Compton time and a typical elementary particle mass. The reasons underlying this parallalism are then discussed in detail.
Time Reversal of Electromagnetic Waves
G. Lerosey; J. de Rosny; A. Tourin; A. Derode; G. Montaldo; M. Fink
We report the first experimental demonstration of time-reversal focusing with electromagnetic waves. An antenna transmits a 1-mus electromagnetic pulse at a central frequency of 2.45GHz in a high-Q cavity. Another antenna records the strongly reverberated signal. The time-reversed wave is built and transmitted back by the same antenna acting now as a time-reversal mirror. The wave is found to converge
Electromagnetically induced grating with maximal atomic coherence
Carvalho, Silvania A.; Araujo, Luis E. E. de [Instituto de Fisica ''Gleb Wataghin'', Universidade Estadual de Campinas, Campinas-SP, 13083-859 Sao Paulo (Brazil)
We describe theoretically an atomic diffraction grating that combines an electromagnetically induced grating with a coherence grating in a double-{Lambda} atomic system. With the atom in a condition of maximal coherence between its lower levels, the combined gratings simultaneously diffract both the incident probe beam as well as the signal beam generated through four-wave mixing. A special feature of the atomic grating is that it will diffract any beam resonantly tuned to any excited state of the atom accessible by a dipole transition from its ground state.
Steven D. Novack; Dale K. Kotter; Dennis Slafer; Patrick Pinhero
This research explores a new efficient approach for producing electricity from the abundant energy of the sun. A nanoantenna electromagnetic collector (NEC) has been designed, prototyped, and tested. Proof of concept has been validated. The device targets mid-infrared wavelengths where conventional photovoltaic (PV) solar cells do not respond but is abundant in solar energy. The initial concept of designing NEC antennas was based on scaling of radio frequency antenna theory. This approach has proven unsuccessful by many due to not fully understanding and accounting for the optical behavior of materials in the THz region. Also until recent years the nanofabrication methods were not available to fabricate the optical antenna elements. We have addressed and overcome both technology barriers. Several factors were critical in successful implementation of NEC including: 1) frequency-dependent modeling of antenna elements, 2) selection of materials with proper THz properties and 3) novel manufacturing methods that enable economical large-scale manufacturing. The work represents an important step toward the ultimate realization of a low-cost device that will collect as well as convert this radiation into electricity, which will lead to a wide spectrum, high conversion efficiency, and low cost solution to complement conventional PVs.
Electromagnetism of Bacterial Growth
NASA Astrophysics Data System (ADS)
Ainiwaer, Ailiyasi
There has been increasing concern from the public about personal health due to the significant rise in the daily use of electrical devices such as cell phones, radios, computers, GPS, video games and television. All of these devices create electromagnetic (EM) fields, which are simply magnetic and electric fields surrounding the appliances that simultaneously affect the human bio-system. Although these can affect the human system, obstacles can easily shield or weaken the electrical fields; however, magnetic fields cannot be weakened and can pass through walls, human bodies and most other objects. The present study was conducted to examine the possible effects of bacteria when exposed to magnetic fields. The results indicate that a strong causal relationship is not clear, since different magnetic fields affect the bacteria differently, with some causing an increase in bacterial cells, and others causing a decrease in the same cells. This phenomenon has yet to be explained, but the current study attempts to offer a mathematical explanation for this occurrence. The researchers added cultures to the magnetic fields to examine any effects to ion transportation. Researchers discovered ions such as potassium and sodium are affected by the magnetic field. A formula is presented in the analysis section to explain this effect.
Electromagnetic Calorimeter for HADES
W. Czyzycki; E. Epple; L. Fabbietti; M. Golubeva; F. Guber; A. Ivashkin; M. Kajetanowicz; A. Krasa; F. Krizek; A. Kugler; K. Lapidus; E. Lisowski; J. Pietraszko; A. Reshetin; P. Salabura; Y. Sobolev; J. Stanislav; P. Tlusty; T. Torrieri; M. Traxler
We propose to build the Electromagnetic calorimeter for the HADES di-lepton spectrometer. It will enable to measure the data on neutral meson production from nucleus-nucleus collisions, which are essential for interpretation of dilepton data, but are unknown in the energy range of planned experiments (2-10 GeV per nucleon). The calorimeter will improve the electron-hadron separation, and will be used for detection of photons from strange resonances in elementary and HI reactions. Detailed description of the detector layout, the support structure, the electronic readout and its performance studied via Monte Carlo simulations and series of dedicated test experiments is presented. The device will cover the total area of about 8 m^2 at polar angles between 12 and 45 degrees with almost full azimuthal coverage. The photon and electron energy resolution achieved in test experiments amounts to 5-6%/sqrt(E[GeV]) which is sufficient for the eta meson reconstruction with S/B ratio of 0.4% in Ni+Ni collisions at 8 AGeV. A purity of the identified leptons after the hadron rejection, resulting from simulations based on the test measurements, is better than 80% at momenta above 500 MeV/c, where time-of-flight cannot be used.
Electromagnetic Interference on Pacemakers
Erdogan, Okan
External sources, either within or outside the hospital environment, may interfere with the appropriate function of pacemakers which are being implanted all around the world in current medical practice. The patient and the physician who is responsible for follow-up of the pacing systems may be confronted with some specific problems regarding the various types of electromagnetic interference (EMI). To avoid these unwanted EMI effects one must be aware of this potential problem and need to take some precautions. The effects of EMI on pacemaker function and precautions to overcome some specific problems were discussed in this review article. There are many sources of EMI interacting with pacemakers. Magnetic resonance imaging creates real problem and should be avoided in pacemaker patients. Cellular phones might be responsible for EMI when they were held on the same side with the pacemaker. Otherwise they don't cause any specific type of interaction with pacemakers. Sale security systems are not a problem if one walks through it without lingering in or near it. Patients having unipolar pacemaker systems are prone to develop EMI because of pectoral muscle artifacts during vigorous active physical exercise. PMID:17006562
Observation and theoretical simulation of electromagnetically induced transparency and enhanced velocity selective optical pumping in cesium vapour in a micrometric thickness optical cell
NASA Astrophysics Data System (ADS)
Krasteva, A.; Ray, B.; Slavov, D.; Todorov, P.; Ghosh, P. N.; Mitra, S.; Cartaleva, S.
Observation of electromagnetically induced transparency (EIT) and enhanced velocity selective optical pumping (VSOP) signals in a micrometric cell with cesium is reported. The line shape and non-linear features observed in the case of fluorescence in the direction parallel to the cell windows and the transmission spectra observed along the propagation direction of the probe beam show considerable differences in the spectral profile. A theoretical model based on five level optical Bloch equations is used to simulate the spectra. The Doppler convolution includes all possible orientations of atomic velocities with respect to the laser beam direction. Atoms moving nearly parallel to the windows and perpendicular to the collinear pump and probe beams have much lower Doppler shift and hence produce considerable narrowing of the Doppler background in the fluorescence spectra. The coherence decay rate is also low for such atoms as they do not meet with the cell walls. The simulated curves reproduce the observed sharp EIT peaks and enhanced broad VSOP signals for the closed probe transition in the fluorescence and absorption spectra. The observed effect of detuning of the pump frequency on the non-linear features is also reproduced by the simulation.
A new electromagnetic code for ICRF antenna in EAST
Yang, Hua; Dong, Sa; Zhang, Xin-Jun; Zhao, Yan-Ping; Shang, Lei
The demand for an effective tool to help in the design of ion cyclotron radio frequency (ICRF) antenna system for fusion experiment has driven the development of predictive codes. A new electromagnetic code based on the method of moments (MOM) is described in the paper. The code computes the electromagnetic field by the solution of the electric field integral equation. The structure of ICRF antennas are discretized with triangular mesh. By using the new code, the scattering parameter and the surface current are given and compared with the result by commercial code CST. Moreover, the power spectra are studied with different toroidal phases for heating and current drive. Good agreement of simulation results between the new code and CST are obtained. The code has been validated against CST for EAST ICRF antenna.
Electron beam injection during active experiments. I - Electromagnetic wave emissions
NASA Technical Reports Server (NTRS)
Winglee, R. M.; Kellogg, P. J.
The wave emissions produced in Echo 7 experiment by active injections of electron beams were investigated to determine the properties of the electromagnetic and electrostatic fields for both the field-aligned and cross-field injection in such experiments and to evaluate the sources of free energy and relative efficiencies for the generation of the VLF and HF emissions. It is shown that, for typical beam energies in active experiments, electromagnetic effects do not substantially change the bulk properties of the beam, spacecraft charging, and plasma particle acceleration. Through simulations, beam-generated whistlers; fundamental z-mode and harmonic x-mode radiation; and electrostatic electron-cyclotron, upper-hybrid, Langmuir, and lower-hybrid waves were identified. The characteristics of the observed wave spectra were found to be sensitive to both the ratio of the electron plasma frequency to the cyclotron frequency and the angle of injection relative to the magnetic field.
Energy harvesting devices for harvesting energy from terahertz electromagnetic radiation
Novack, Steven D.; Kotter, Dale K.; Pinhero, Patrick J.
Methods, devices and systems for harvesting energy from electromagnetic radiation are provided including harvesting energy from electromagnetic radiation. In one embodiment, a device includes a substrate and one or more resonance elements disposed in or on the substrate. The resonance elements are configured to have a resonant frequency, for example, in at least one of the infrared, near-infrared and visible light spectra. A layer of conductive material may be disposed over a portion of the substrate to form a ground plane. An optical resonance gap or stand-off layer may be formed between the resonance elements and the ground plane. The optical resonance gap extends a distance between the resonance elements and the layer of conductive material approximately one-quarter wavelength of a wavelength of the at least one resonance element's resonant frequency. At least one energy transfer element may be associated with the at least one resonance element.
Structures, systems and methods for harvesting energy from electromagnetic radiation
Novack, Steven D. (Idaho Falls, ID); Kotter, Dale K. (Shelley, ID); Pinhero, Patrick J. (Columbia, MO)
Methods, devices and systems for harvesting energy from electromagnetic radiation are provided including harvesting energy from electromagnetic radiation. In one embodiment, a device includes a substrate and one or more resonance elements disposed in or on the substrate. The resonance elements are configured to have a resonant frequency, for example, in at least one of the infrared, near-infrared and visible light spectra. A layer of conductive material may be disposed over a portion of the substrate to form a ground plane. An optical resonance gap or stand-off layer may be formed between the resonance elements and the ground plane. The optical resonance gap extends a distance between the resonance elements and the layer of conductive material approximately one-quarter wavelength of a wavelength of the at least one resonance element's resonant frequency. At least one energy transfer element may be associated with the at least one resonance element.
Temperatures of Fragment Kinetic Energy Spectra
Wolfgang Bauer
Multifragmentation reactions without large compression in the initial state (proton-induced reactions, reverse-kinematics, projectile fragmentation) are examined, and it is verified quantitatively that the high temperatures obtained from fragment kinetic energy spectra and lower temperatures obtained from observables such as level population or isotope ratios can be understood in a common framework.
Dipolar radiation from spinning dust grains coupled to an electromagnetic wave
Guerreiro, A; Mendonça, J T; Bingham, R
In this letter we investigate how the complex rotation and quivering motion of an elongated polarized dust grain in the presence of a monochromatic electromagnetic wave can originate dipolar emission with two distinct spectral components. We present a model for the emission of radiation by elongated polarized dust grains under the influence of both an external electromagnetic wave and a constant background magnetic field. The dust, exhibiting rotational motion at the external electromagnetic field frequency w0 as well as quivering motion at frequency W0, proportional to the em field amplitude, will radiate with frequencies that will depend on the external field wavelength and amplitude. The radiated spectra exibits a frequency around w0, and sidebands at w0+-W0 and w0+-2W0. Since the amplitude and the frequency of the background electromagnetic field are independent parameters, this model establishes a correlation between different spectral components of galactic dipolar emission, which may help to explain th...
Level Anticrossing of Impurity States in Semiconductor Nanocrystals
Baimuratov, Anvar S.; Rukhlenko, Ivan D.; Turkov, Vadim K.; Ponomareva, Irina O.; Leonov, Mikhail Yu.; Perova, Tatiana S.; Berwick, Kevin; Baranov, Alexander V.; Fedorov, Anatoly V.
The size dependence of the quantized energies of elementary excitations is an essential feature of quantum nanostructures, underlying most of their applications in science and technology. Here we report on a fundamental property of impurity states in semiconductor nanocrystals that appears to have been overlooked—the anticrossing of energy levels exhibiting different size dependencies. We show that this property is inherent to the energy spectra of charge carriers whose spatial motion is simultaneously affected by the Coulomb potential of the impurity ion and the confining potential of the nanocrystal. The coupling of impurity states, which leads to the anticrossing, can be induced by interactions with elementary excitations residing inside the nanocrystal or an external electromagnetic field. We formulate physical conditions that allow a straightforward interpretation of level anticrossings in the nanocrystal energy spectrum and an accurate estimation of the states' coupling strength. PMID:25369911
Background noise spectra of global seismic stations
Wada, M.M.; Claassen, J.P.
Over an extended period of time station noise spectra were collected from various sources for use in estimating the detection and location performance of global networks of seismic stations. As the database of noise spectra enlarged and duplicate entries became available, an effort was mounted to more carefully select station noise spectra while discarding others. This report discusses the methodology and criteria by which the noise spectra were selected. It also identifies and illustrates the station noise spectra which survived the selection process and which currently contribute to the modeling efforts. The resulting catalog of noise statistics not only benefits those who model network performance but also those who wish to select stations on the basis of their noise level as may occur in designing networks or in selecting seismological data for analysis on the basis of station noise level. In view of the various ways by which station noise were estimated by the different contributors, it is advisable that future efforts which predict network performance have available station noise data and spectral estimation methods which are compatible with the statistics underlying seismic noise. This appropriately requires (1) averaging noise over seasonal and/or diurnal cycles, (2) averaging noise over time intervals comparable to those employed by actual detectors, and (3) using logarithmic measures of the noise.
NSDL National Science Digital Library
This activity introduces two different representations of spectra: the photographic representation, such as the rainbow, and the graphical representation used more often by astronomers. A rainbow is often given as an everyday example of a spectrum. Most students have seen a rainbow, so this example is used to help make the unfamiliar more familiar. However, the spectra that scientists use, which students will see in this lesson plan, appear very different than a rainbow. In this activity, students will explore for themselves two different representations of the same spectrum, noting advantages and disadvantages of each. They will explore the differences and similarities of both these representations, and will develop a more intuitive feel for a graphical representation, which may not yet be familiar to them.
NASA Technical Reports Server (NTRS)
The color image on the lower left shows a rock outcrop at Meridiani Planum, Mars. This image was taken by the panoramic camera on the Mars Exploration Rover Opportunity, looking north, and was acquired on the 4th sol, or martian day, of the rover's mission (Jan. 27, 2004). The yellow box outlines an area detailed in the top left image, which is a monochrome (single filter) image from the rover's panoramic camera. The top image uses solid colors to show several regions on or near the rock outcrop from which spectra were extracted: the dark soil above the outcrop (yellow), the distant horizon surface (aqua), a bright rock in the outcrop (green), a darker rock in the outcrop (red), and a small dark cobblestone (blue). Spectra from these regions are shown in the plot to the right.
Experimental evidence of electromagnetic pollution of ionosphere
NASA Astrophysics Data System (ADS)
Pronenko, Vira; Korepanov, Valery; Dudkin, Denis
The Earth's ionosphere responds to external perturbations originated mainly in the Sun, which is the primary driver of the space weather (SW). But solar activity influences on the ionosphere and the Earth's atmosphere (i.e., the energy transfer in the direction of the Sun-magnetosphere-ionosphere-atmosphere-surface of the Earth), though important, is not a unique factor affecting its state - there is also a significant impact of the powerful natural and anthropogenic processes, which occur on the Earth's surface and propagating in opposite direction along the Earth's surface-atmosphere-ionosphere-magnetosphere chain. Numerous experimental data confirm that the powerful sources and consumers of electrical energy (radio transmitters, power plants, power lines and industrial objects) cause different ionospheric phenomena, for example, changes of the electromagnetic (EM) field and plasma in the ionosphere, and affect on the state of the Earth atmosphere. Anthropogenic EM effects in the ionosphere are already observed by the scientific satellites and the consequences of their impact on the ionosphere are not currently known. Therefore, it is very important and urgent task to conduct the statistically significant research of the ionospheric parameters variations due to the influence of the powerful man-made factors, primarily owing to substantial increase of the EM energy production. Naturally, the satellite monitoring of the ionosphere and magnetosphere in the frequency range from tens of hertz to tens of MHz with wide ground support offers the best opportunity to observe the EM energy release, both in the global and local scales. Parasitic EM radiation from the power supply lines, when entering the ionosphere-magnetosphere system, might have an impact on the electron population in the radiation belt. Its interaction with trapped particles will change their energy and pitch angles; as a result particle precipitations might occur. Observations of EM emission by multiple low orbiting satellites have confirmed a significant increase in their intensity over the populated areas of Europe and Asia. Recently, there are many experimental evidences of the existence of power line harmonic radiation (PLHR) in the ionosphere. Their spectra consist of succession of 50 (60) Hz harmonics which is accompanied by a set of lines separated by 50 (60) or 100 (120) Hz - the central frequency of which is shifted to high frequency. These lines cover rather wide band - according to the available experimental data, their central frequencies are observed from ~1.5 - 3 kHz up to 15 kHz, and recently the main mains frequencies are also observed. The examples of power line harmonic radiation, which were detected by "Sich-1M", "Chibis-M" and "Demeter" satellites, have been presented and discussed. The available experimental data, as well as theoretical estimations, allow us with a high degree of certainty to say that the permanent satellite monitoring of the ionospheric and magnetospheric anthropogenic EM perturbations is necessary for: a) objective assessment and prediction of the space weather conditions; b) evaluation of the daily or seasonal changes in the level of energy consumption; c) construction of a map for estimation of near space EM pollution. This study is partially supported by SSAU contract N 4-03/13.
A. B. Kaidalov; V. A. Khoze; A. D. Martin; M. G. Ryskin
It is shown that the observation of the spectra of leading neutrons from proton beams can be a good probe of absorptive and migration effects. We quantify how these effects modify the Reggeized pion-exchange description of the measurements of leading neutrons at HERA. We are able to obtain a satisfactory description of all the features of these data. We also briefly discuss the corresponding data for leading baryons produced in hadron-hadron collisions.
NASA Technical Reports Server (NTRS)
Young, L. G.
A historical account of observations of Venus and their interpretation is given. The major constituent of the atmosphere on Venus (CO2) was detected spectroscopically forty years ago, and minor constituents (CO, HF, HCl) have been found more recently. The infrared spectra also provide a means of studying the motions of her cloudly atmosphere. The composition of the clouds has been sought in the reflection spectrum of Venus, and some of the evidence for their nature is discussed.
FOREWORD: Special section on electromagnetic characterization of buried obstacles
Dominique Lesselier; Weng Cho Chew
This Inverse Problems special section on electromagnetic characterization of buried obstacles contains a selection of 14 invited papers, involving 41 authors and 19 research groups worldwide. (Though this section consists of invited papers, the standard refereeing procedures of Inverse Problems have been rigorously observed.) We do not claim to have reached all the high-level researchers in the field, but we
Nonionizing electromagnetic wave effects in biological materials and systems
C. C. Johnson; A. W. Guy
Electromagnetic waves from the lower radio frequencies up through the optical spectrum can generate a myriad of effects and responses in biological specimens. Some of these effects can be harmful to man at high radiation intensities, producing burns, cataracts, chemical changes, etc. Biological effects have been reported at lower radiation intensities, but it is not now known if low-level effects
Design of a bounded wave EMP (Electromagnetic Pulse) simulator
P. A. A. Sevat
Electromagnetic Pulse (EMP) simulators are used to simulate the EMP generated by a nuclear weapon and to harden equipment against the effects of EMP. At present, DREO has a 1 m EMP simulator for testing computer terminal size equipment. To develop the R and D capability for testing larger objects, such as a helicopter, a much bigger threat level facility
Introduction to Eye-Opening Technology: The Electromagnetic Spectrum.
ERIC Educational Resources Information Center
Smith, Denise; Eisenhamer, Bonnie; DeVore, Edna; Bianchi, Luciana
Provides classroom activities centered around how the electromagnetic spectrum yields vital insights about the evolution of the universe. Activities targeted for grade levels 6-12 illustrate the importance of light and color in space exploration. Includes a poster. (Author/SOE)
Analytical calculation of two-dimensional spectra.
Bell, Joshua D; Conrad, Rebecca; Siemens, Mark E
We demonstrate an analytical calculation of two-dimensional (2D) coherent spectra of electronic or vibrational resonances. Starting with the solution to the optical Bloch equations for a two-level system in the 2D time domain, we show that a fully analytical 2D Fourier transform can be performed if the projection-slice and Fourier-shift theorems of Fourier transforms are applied. Results can be fit to experimental 2D coherent spectra of resonances with arbitrary inhomogeneity. PMID:25831281
Velocity determination from velocity spectra
Yang, Sung Jin
' 1300C 14 00 I SUOX 5DQ SOQ ((CP I UI. O HEI/g ng Q T I m E. ITI 5 I'0 I'K )) tQ~P Tl fflE ITS ()l) ) -" SOD (& (U) 0GU 9 5 3 00 ~SP 3500 B ODD Sooof I ODQC flooo 12CD f 3000 1400$ I SRlG Q Figure 15. Ve1ocity spectra...; interval velocity, ft/sec h; thickness, ft d; depth from sea level, ft layer no. 12. 5 20. 5 location (89 no, ) 28. 5 39 43 52 V 1 h d V 2 h d V V 4 h d V 5 h d V 6 h d V 7 h d 6, 400 1, 312 1 &312 8, 549 898 2, 210 11, 311...
Statistical Properties of Electromagnetic Environment in Wireless Networks, Intra-Network Electromagnetic Compatibility and Safety
Loyka, Sergey
and Radioelectronics (BSUIR) Electromagnetic Compatibility Laboratory 6, P.Brovki st., Minsk 220013, Belarus E Electromagnetic compatibility (EMC) and safety (EMS) of wireless communication networks have been recently
Step-up converter for electromagnetic vibrational energy scavenger
Saha, C; Godsell, J; Carlioz, L; Wang, N; Mccloskey, P; Beeby, S; Tudor, J; Torah, Russel
This paper introduces a voltage multiplier (VM) circuit which can step up a minimum voltage of 150 mV (peak). The operation and characteristics of this converter circuit are described. The voltage multiplier circuit is also tested with micro and macro scale electromagnetic vibrational generators and the effect of the VM on the optimum load conditions of the electromagnetic generator is presented. The measured results show that 85% efficiency can be achieved from this VM circuit at a power level of 18 ?W.
Electromagnetic absorption of semiconductor 2D Majorana nanowires.
Ruiz, Daniel; Osca, Javier; Serra, Llorenç
We calculate the cross section for the electromagnetic absorption of planar 2D Majorana nanowires. The electromagnetic field is described in the dipole approximation. We discuss the signatures on the cross section of a near-zero-energy mode. A low energy peak for transverse polarization, absent in the longitudinal one, reveals the presence of the Majorana-like state. This peak is relatively robust against the thermal smearing of the level occupations. We consider the influence of optical masks hiding parts of the nanowire from the radiation. PMID:25756993
Electromagnetically Induced Transparency from a Single Atom in Free Space
L. Slodicka; G. Hetet; S. Gerber; M. Hennrich; R. Blatt
We report an absorption spectroscopy experiment and the observation of electromagnetically induced transparency from a single trapped atom. We focus a weak and narrowband Gaussian light beam onto an optically cooled Barium ion using a high numerical aperture lens. Extinction of this beam is observed with measured values of up to 1.3 %. We demonstrate electromagnetically induced transparency of the ion by tuning a strong control beam over a two-photon resonance in a three-level lambda-type system. The probe beam extinction is inhibited by more than 75 % due to population trapping.
Space physics and the teaching of undergraduate electromagnetism
NASA Astrophysics Data System (ADS)
Lopez, R. E.
Space physics is not a subject typically found in the undergraduate curriculum, and it is rare even at the graduate level. On the other hand, the basis of space physics is electromagnetism and the motion of charged particles, which are common topics in both the introductory and advanced undergraduate physics curriculum, and examples from space physics can be used to enliven instruction. In this paper, I will discuss various topics commonly found in both introductory and upper-division electricity and magnetism classes where examples from space physics may facilitate student understanding or provide interesting, real-life examples of electromagnetism in action.
Electromagnetic absorption of semiconductor 2D Majorana nanowires
NASA Astrophysics Data System (ADS)
Ruiz, Daniel; Osca, Javier; Serra, Llorenç
We calculate the cross section for the electromagnetic absorption of planar 2D Majorana nanowires. The electromagnetic field is described in the dipole approximation. We discuss the signatures on the cross section of a near-zero-energy mode. A low energy peak for transverse polarization, absent in the longitudinal one, reveals the presence of the Majorana-like state. This peak is relatively robust against the thermal smearing of the level occupations. We consider the influence of optical masks hiding parts of the nanowire from the radiation.
Magnetically coupled electromagnetically induced transparency analogy of dielectric metamaterial
Zhang, Fuli, E-mail: email@example.com; He, Xuan [Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education and Department of Applied Physics, School of Science, Northwestern Polytechnical University, Xi'an 710072 (China); Zhao, Qian [State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Lan, Chuwen; Zhou, Ji [State Key Laboratory of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Zhang, Weihong, E-mail: firstname.lastname@example.com; Qiu, Kepeng [School of Mechanical Engineering, P.O. Box 552, Northwestern Polytechnical University, Xi'an 710072 (China)
In this manuscript, we experimentally demonstrate magnetically coupled electromagnetically induced transparency (EIT) analogy effect inside dielectric metamaterial. In contrast to previous studies employed different metallic topological microstructures to introduce dissipation loss change, barium strontium titanate, and calcium titanate (CaTiO{sub 3}) are chosen as the bright and dark EIT resonators, respectively, due to their different intrinsic dielectric loss. Under incident magnetic field excitation, dielectric metamaterial exhibits an EIT-type transparency window around 8.9?GHz, which is accompanied by abrupt change of transmission phase. Numerical calculations show good agreement with experiment spectra and reveal remarkably increased group index, indicating potential application in slow light.
The Spectrum of Electromagnetic Jets from Kerr Black Holes and Naked Singularities in the Teukolsky Perturbation Theory
Denitsa R. Staicova; Plamen P. Fiziev
We give a new theoretical basis for examination of the presence of the Kerr black hole (KBH) or the Kerr naked singularity (KNS) in the central engine of different astrophysical objects around which astrophysical jets are typically formed: X-ray binary systems, gamma ray bursts (GRBs), active galactic nuclei (AGN), etc. Our method is based on the study of the exact solutions of the Teukolsky master equation for electromagnetic perturbations of the Kerr metric. By imposing original boundary conditions on the solutions so that they describe a collimated electromagnetic outflow, we obtain the spectra of possible {\\em primary jets} of radiation, introduced here for the first time. The theoretical spectra of primary electromagnetic jets are calculated numerically. Our main result is a detailed description of the qualitative change of the behavior of primary electromagnetic jet frequencies under the transition from the KBH to the KNS, considered here as a bifurcation of the Kerr metric. We show that quite surprisingly the novel spectra describe linearly stable primary electromagnetic jets from both the KBH and the KNS. Numerical investigation of the dependence of these primary jet spectra on the rotation of the Kerr metric is presented and discussed.
Terahertz electromagnetic wave generation and amplification by an electron beam in the elliptical plasma waveguides with dielectric rod
Rahmani, Z., E-mail: email@example.com; Jazi, B. [Department of Laser and Photonics, Faculty of Physics, University of Kashan, Kashan (Iran, Islamic Republic of); Heidari-Semiromi, E. [Department of Condense Matter, Faculty of Physics, University of Kashan, Kashan (Iran, Islamic Republic of)
The propagation of electromagnetic waves in an elliptical plasma waveguide including strongly magnetized plasma column and a dielectric rod is investigated. The dispersion relation of guided hybrid electromagnetic waves is obtained. Excitation of the waves by a thin annular relativistic elliptical electron beam will be studied. The time growth rate of electromagnetic waves is obtained. The effects of relative permittivity constant of dielectric rod, radius of dielectric rod, accelerating voltage, and current density of the annular elliptical beam on the growth rate and the frequency spectra are numerically presented.
Theoretical Studies of Molecular Spectra
NASA Technical Reports Server (NTRS)
McKay, Christopher (Technical Monitor); Freedman, Richard S.
This summary describes the research activities of the principal investigator during the reporting period. The research includes spectroscopy, management of molecular databases, and generation of spectral line profiles and opacity data. The spectroscopy research includes oxygen broadening of nitric oxide (NO), analysis of CO2 spectra, analysis of HNO3 spectra, and analysis of CO spectra.
REVIEWS OF TOPICAL PROBLEMS: Thermally stimulated electromagnetic fields of solids
NASA Astrophysics Data System (ADS)
Vinogradov, Evgeny A.; Dorofeev, Illarion A.
Different ways to calculate the spectral properties of fluctuating electromagnetic fields produced by solids are reviewed, all of which essentially reduce to solving the Maxwell equations for a specified geometry and boundary conditions and then using the fluctuation--dissipation theorem. It is shown that in the practical case of plane-layered solids, all correlation characteristics of thermal fields can be expressed in terms of the Fresnel coefficients. The experimental results on thermally stimulated electromagnetic fields from solids are in qualitative and quantitative agreement with model calculations and theoretical expectations. The dispersion interaction between solid bodies in different thermodynamic states, the fluctuating fields as a means of body-to-body energy transfer, and the shift, broadening, and deexcitation of energy levels in a particle near a solid surface are discussed using the theory of thermally stimulated electromagnetic fields.
Design of a bounded wave EMP (Electromagnetic Pulse) simulator
NASA Astrophysics Data System (ADS)
Sevat, P. A. A.
Electromagnetic Pulse (EMP) simulators are used to simulate the EMP generated by a nuclear weapon and to harden equipment against the effects of EMP. At present, DREO has a 1 m EMP simulator for testing computer terminal size equipment. To develop the R and D capability for testing larger objects, such as a helicopter, a much bigger threat level facility is required. This report concerns the design of a bounded wave EMP simulator suitable for testing large size equipment. Different types of simulators are described and their pros and cons are discussed. A bounded wave parallel plate type simulator is chosen for it's efficiency and the least environmental impact. Detailed designs are given for 6 m and 10 m parallel plate type wire grid simulators. Electromagnetic fields inside and outside the simulators are computed. Preliminary specifications for a pulse generator required for the simulator are also given. Finally, the electromagnetic fields radiated from the simulator are computed and discussed.
Active System for Electromagnetic Perturbation Monitoring in Vehicles
NASA Astrophysics Data System (ADS)
Matoi, Adrian Marian; Helerea, Elena
Nowadays electromagnetic environment is rapidly expanding in frequency domain and wireless services extend in terms of covered area. European electromagnetic compatibility regulations refer to limit values regarding emissions, as well as procedures for determining susceptibility of the vehicle. Approval procedure for a series of cars is based on determining emissions/immunity level for a few vehicles picked randomly from the entire series, supposing that entire vehicle series is compliant. During immunity assessment, the vehicle is not subjected to real perturbation sources, but exposed to electric/magnetic fields generated by laboratory equipment. Since current approach takes into account only partially real situation regarding perturbation sources, this paper proposes an active system for determining electromagnetic parameters of vehicle's environment, that implements a logical diagram for measurement, satisfying the imposed requirements. This new and original solution is useful for EMC assessment of hybrid and electrical vehicles.
NASA Technical Reports Server (NTRS)
Sullivan, Edward C.; Bohlin, Ralph C.; Heap, Sara R.; West, Donald K.; Schmitz, Marion
The International Ultraviolet Explorer (IUE) Satellite has been in continuous operation since January 26, 1978. To date, approximately 65,000 spectra have been stored in an archive at Goddard Space Flight Center in Greenbelt, MD. A number of procedures have been generated to facilitate access to the data in the IUE spectral archive. This document describes the procedures which include on-line quick look of the displays, search of an observation data base for selected observations, and several methods for ordering data from the archive.
Wang, Rong; Zhang, Bao-Min
By testing the Raman spectra of megacryst pyroxene, enstatite and diopside in terms of location, shape and intensity, the symmetries of the main spectral band of pyroxene and the vibration modes of Raman shift were identified. The spectral bands of corresponding ionic groups such as non-bridge oxygen Si-O- and bridge oxygen Si-O0, O-Si-O and M-O were assigned for vibrational mode. Through the change in the intensity of the spectral band in different section direction and the deficiency of some spectral bands, the orientation problem in mineral crystallography was preliminarily studied. PMID:20384128
NASA Astrophysics Data System (ADS)
Kaler, James B.
1. Stars; 2. Atoms and spectra; 3. The spectral sequence; 4. The M stars: red supergiants to dwarfs; 5. Descending the staircase: class L; 6. The wet basement: class T; 7. The K stars: orange giants and brighter dwarfs; 8. Our Sun and its cousins: the G stars; 9. Class F: stars in transition; 10. The white stars of class A; 11. The B stars: beacons of the skies; 12. Class O: the head of the spectral sequence; 13. Extraordinary classes; 14. Journeys on the HR diagram; Star index; Subject index.
Electromagnetically induced transparency for a double Fano-profile system
NASA Astrophysics Data System (ADS)
Bui Dinh, Thuan; Cao Long, Van; Leo?ski, Wies?aw; Pe?ina, Jan
A ?-like model of atomic levels involving two auto-ionizing states is considered. The levels are irradiated by two external electromagnetic fields, a strong driving and a weak probing ones. The analytical formula for medium susceptibility shows an additional electromagnetically induced transparency window caused by the second auto-ionizing level. Characteristics of both transparency windows are analyzed depending on parameters of auto-ionizing levels and the external driving field. Manipulation of these characteristics seems to be very effective because of their large sensitivity with respect to the parameters involved in the problem. This manipulation becomes even more feasible when considered model is implemented in so-called laser-induced continuum structure.
Electromagnetic fields and public health.
Aldrich, T E; Easterly, C E
A review of the literature is provided for the topic of health-related research and power frequency electromagnetic fields. Minimal evidence for concern is present on the basis of animal and plant research. General observation would accord with the implication that there is no single and manifest health effect as the result of exposure to these fields. There are persistent indications, however, that these fields have biologic activity, and consequently, there may be a deleterious component to their action, possibly in the presence of other factors. Power frequency electromagnetic field exposures are essentially ubiquitous in modern society, and their implications in the larger perspective of public health are unclear at this time. Electromagnetic fields represent a methodological obstacle for epidemiologic studies and a quandary for risk assessment; there is need for more data. PMID:3319560
Un-renormalized classical electromagnetism
Ibison, Michael [Institute for Advanced Studies at Austin, 4030 West Braker Lane, Suite 300, Austin, TX 78759 (United States)]. E-mail: firstname.lastname@example.com
This paper follows in the tradition of direct-action versions of electromagnetism having the aim of avoiding a balance of infinities wherein a mechanical mass offsets an infinite electromagnetic mass so as to arrive at a finite observed value. However, the direct-action approach ultimately failed in that respect because its initial exclusion of self-action was later found to be untenable in the relativistic domain. Pursing the same end, this paper examines instead a version of electromagnetism wherein mechanical action is excluded and self-action is retained. It is shown that the resulting theory is effectively interacting due to the presence of infinite forces. A vehicle for the investigation is a pair of classical point charges in a positronium-like arrangement for which the orbits are found to be self-sustaining and naturally quantized.
Electromagnetic Fields and Public Health
Timothy E. Aldrich; Clay E. Easterly
A review of the literature is provided for the topic of health-related research and power frequency electromagnetic fields. Minimal evidence for concern is present on the basis of animal and plant research. General observation would accord with the implication that there is no single and manifest health effect as the result of exposure to these fields. There are persistent indications, however, that these fields have biologic activity, and consequently, there may be a deleterious component to their action, possibly in the presence of other factors. Power frequency electromagnetic field exposures are essentially ubiquitous in modern society, and their implications in the larger perspective of public health are unclear at this time. Electromagnetic fields represent a methodological obstacle for epidemiologic studies and a quandary for risk assessment; there is need for more data.
Biological effects of electromagnetic fields.
Macrě, M. A.; Di Luzio, Sr.; Di Luzio, S.
Nowadays, concerns about hazards from electromagnetic fields represent an alarming source for human lives in technologically developed countries. We are surrounded by electromagnetic fields everywhere we spend our working hours, rest or recreational activities. The aim of this review is to summarize the biological effects due to these fields arising from power and transmission lines, electrical cable splices, electronic devices inside our homes and work-places, distribution networks and associated devices such as cellular telephones and wireless communication tower, etc. Special care has been reserved to study the biological effects of electromagnetic fields on cell lines of the mammalian immune system about which our research group has been working for several years. PMID:12590871
Constraining neutrino electromagnetic properties by germanium detectors
Jiunn-Wei Chen; Hsin-Chang Chi; Keh-Ning Huang; Hau-Bin Li; C. -P. Liu; Lakhwinder Singh; Henry T. Wong; Chih-Liang Wu; Chih-Pan Wu
The electromagnetic properties of neutrinos, which are either trivial or negligible in the context of the Standard Model, can probe new physics and have significant implications in astrophysics and cosmology. The current best direct limits on the neutrino millicharges and magnetic moments are both derived from data taken with germanium detectors with low thresholds at keV levels. In this paper, we discuss in detail a robust, ab initio method: the multiconfiguration relativistic random phase approximation, that enables us to reliably understand the germanium detector response at the sub-keV level, where atomic many-body physics matters. Using existing data with sub-keV thresholds, limits on reactor antineutrino's millicharge, magnetic moment, and charge radius squared are derived. The projected sensitivities for next generation experiments are also given and discussed.
Holographic Estimate of Electromagnetic Mass
Deog Ki Hong
Using the gauge/gravity duality, we calculate the electromagnetic contributions to hadron masses, where mass generates dynamically by strong QCD interactions. Based on the Sakai-Sugimoto model of holographic QCD we find that the electromagnetic mass of proton is 0.48 MeV larger than that of neutron, which is in agreement with recent lattice results. Similarly for pions we obtain $m_{\\pi^{\\pm}}-m_{\\pi^0}$=3.6 ~ 7.2 MeV, close to the experimental value, taking a ultraviolet cutoff $\\Lambda\\simeq 4M_{\\rm KK}$.
Electromagnetic Gun With Commutated Coils
NASA Technical Reports Server (NTRS)
Elliott, David G.
Proposed electromagnetic gun includes electromagnet coil, turns of which commutated in sequence along barrel. Electrical current fed to two armatures by brushes sliding on bus bars in barrel. Interaction between armature currents and magnetic field from coil produces force accelerating armature, which in turn, pushes on projectile. Commutation scheme chosen so magnetic field approximately coincides and moves with cylindrical region defined by armatures. Scheme has disadvantage of complexity, but in return, enables designer to increase driving magnetic field without increasing armature current. Attainable muzzle velocity increased substantially.
Electromagnetic radiation by gravitating bodies
Iwo Bialynicki-Birula; Zofia Bialynicka-Birula
Gravitating bodies in motion, regardless of their constitution, always produce electromagnetic radiation in the form of photon pairs. This phenomenon is an analog of the radiation caused by the motion of dielectric (or magnetic) bodies. It is a member of a wide class of phenomena named dynamical Casimir effects, and it may be viewed as the squeezing of the electromagnetic vacuum. Production of photon pairs is a purely quantum-mechanical effect. Unfortunately, as we show, the emitted radiation is extremely weak as compared to radiation produced by other mechanisms.
Electromagnetic decay of {lambda}(1520)
Myhrer, F. [Department of Physics and Astronomy, University of South Carolina, Columbia, South Carolina 29208 (United States)
The electromagnetic decay processes of excited hyperon states are a very sensitive probe of the structure of hyperons. We will argue that the recent measurements of electromagnetic decay rates indicate that the wave functions of the hyperon ground states should contain sizable components of excited quark states (configuration mixing). Flavor-SU(3) is a broken symmetry and it appears that the hyperon wave functions should preferably be written in a uds-basis, where only the light u and d-quarks are symmetrized, and not in the usual SU(6)-basis.
Electromagnetic interference (EMI) of system-on-package (SOP)
Toshio Sudo; Hideki Sasaki; Norio Masuda; James L. Drewniak
Electromagnetic interference (EMI) issues are expected to be crucial for next-generation system-on-package (SOP) integrated high-performance digital LSIs and for radio frequency (RF) and analog circuits. Ordinarily in SOPs, high-performance digital LSIs are sources of EMI, while RF and analog circuits are affected by EMI (victims). This paper describes the following aspects of EMI in SOPs: 1) die\\/package-level EMI; 2) substrate-level
Nonlinear wave mixing with electromagnetically induced transparency in cold atoms
Hoonsoo Kang; Gessler Hernandez; Yifu Zhu
Electromagnetically induced transparency (EIT) in a four-level atomic system suppresses linear absorption and leads to resonantly enhanced slow-light four-wave mixing at low light intensities. We analyse the backward four-wave mixing in the four-level system under the EIT conditions, derive the four-wave-mixing efficiency and discuss slow-light propagation conditions. We present experimental measurements of resonant four-wave mixing with the backward scheme in
Observation of atomic localization using electromagnetically induced transparency
Proite, N. A.; Simmons, Z. J.; Yavuz, D. D. [Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706 (United States)
We present a proof-of-principle experiment in which the population of an atomic level is spatially localized using the technique of electromagnetically induced transparency (EIT). The key idea is to utilize the sensitive dependence of the dark state of EIT on the intensity of the coupling laser beam. By using a sinusoidal intensity variation (standing wave), we demonstrate that the population of a specific hyperfine level can be localized much more tightly than the spatial period.
I. What is electromagnetic radiation and the electromagnetic spectrum?
Sitko, Michael L.
, they are all the same kind of "stuff." They all travel through space and have similar electrical and magnetic effects on matter. This "stuff" is called electromagnetic radiation, because it travels (radiates) and has. Human Eye Response { increasing increasing decreasing decreasing decreasing increasing ENERGY frequency
Visible Light and the Electromagnetic Spectrum
NSDL National Science Digital Library
Integrated Teaching and Learning Program,
During this lesson, the electromagnetic spectrum is explained and students learn that visible light makes up only a portion of this wide spectrum. Students also learn that engineers use electromagnetic waves for many different applications.
Electromagnetic formation flight dipole solution planning
Schweighart, Samuel A. (Samuel Adam), 1977-
Electromagnetic Formation Flight (EMFF) describes the concept of using electromagnets (coupled with reaction wheels) to provide all of the necessary forces and torques needed to maintain a satellite's relative position and ...
The electromagnetic spectrum : waves of energy
NSDL National Science Digital Library
Tracy Coulson
In this lesson, students will (1) understand that the sun energy is transferred to Earth by electromagnetic waves, which are transverse waves, (2) understand that there are eight main types of electromagnetic waves, classified on the electromagnetic spectrum according to their wavelengths, and (3) understand how each of the types of electromagnetic radiation is used or found in our everyday lives. This would be a suitable activity for small groups.
Electromagnetic effects on geodesic acoustic modes
Bashir, M. F., E-mail: firstname.lastname@example.com [Salam Chair in Physics, G. C. University Lahore, Katchery Road, Lahore 54000 (Pakistan); Department of Physics, G. C. University Lahore, Katchery Road, Lahore 54000 (Pakistan); Smolyakov, A. I. [University of Saskatchewan, 116 Science Place, Saskatoon S7N 5E2 (Canada); Institute of Tokamak Physics, NRC "Kurchatov Institute," 123182 Moscow (Russian Federation); Elfimov, A. G. [Institute of Physics, University of Săo Paulo, Săo Paulo 05508-090 (Brazil); Melnikov, A. V. [Institute of Tokamak Physics, NRC "Kurchatov Institute," 123182 Moscow (Russian Federation); National Research Nuclear University MEPhI, 115409, Moscow (Russian Federation); Murtaza, G. [Visiting Professor, Department of Physics, Quaid-e-Azam University, Islamabad (Pakistan)
By using the full electromagnetic drift kinetic equations for electrons and ions, the general dispersion relation for geodesic acoustic modes (GAMs) is derived incorporating the electromagnetic effects. It is shown that m?=?1 harmonic of the GAM mode has a finite electromagnetic component. The electromagnetic corrections appear for finite values of the radial wave numbers and modify the GAM frequency. The effects of plasma pressure ?{sub e}, the safety factor q, and the temperature ratio ? on GAM dispersion are analyzed.
Why Study Electromagnetics: The First Unit in an Undergraduate Electromagnetics Course
Taflove, Allen
1 Why Study Electromagnetics: The First Unit in an Undergraduate Electromagnetics Course Allen unification of electric and magnetic fields predicting electromagnetic wave phenomena which Nobel Laureate: "Of what relevance is the study of electromagnetics to our modern society?" The goal of this unit
STIMULATED ELECTROMAGNETIC EMISSIONS BY HIGH-FREQUENCY ELECTROMAGNETIC PUMPING OF THE IONOSPHERIC.S.A. Abstract. A high frequency electromagnetic pump wave transmitted into the ionospheric plasma from the ground can stimulate electromagnetic radiation with frequencies around that of the ionospher- ically
Donuts make diffractionless electromagnetic waves
Ya-Lun Tsai; Jyun-Hong Lu; Hua-Kung Chiu; Ching-Yi Chen; Chii-Chang Chen; Jenq-Yang Chang
This work finds that a diffractionless beam can be obtained using periodically arranged donut (torus) waveguides. The Bessel-like field distribution is observed at the output of the waveguide. The structure may be built for electromagnetic waves of any wavelength, including radiowaves, microwaves, infrared light, visible light and UV light. The diameter of the diffractionless beam is of the order of
Explanations, Education, and Electromagnetic Fields.
ERIC Educational Resources Information Center
Friedman, Sharon M.
Explaining complex scientific and environmental subjects in the mass media is difficult to do, particularly under such constraints as short deadlines and lack of space or time. When a scientific controversy and human health risk are involved, this becomes an even harder task to accomplish. The subject of electromagnetic fields (EMF) involves…
Proposed electromagnetic wave energy converter
NASA Technical Reports Server (NTRS)
Bailey, R. L.
Device converts wave energy into electric power through array of insulated absorber elements responsive to field of impinging electromagnetic radiation. Device could also serve as solar energy converter that is potentially less expensive and fragile than solar cells, yet substantially more efficient.
The Electromagnetic Spectrum: Resonating Atmosphere
NSDL National Science Digital Library
Using a paper and tape device, students experience how atoms and molecules of gas in Earth's atmosphere absorb electromagnetic energy through resonance. This activity is part of Unit 2 in the Space Based Astronomy guide that contains background information, worksheets, assessments, extensions, and standards.
Technology-based electromagnetic education
Magdy F. Iskander
In this paper, we briefly review the various roles of technology in stimulating interest and deepening understanding of abstract and highly mathematical subjects such as electromagnetics (EM). The general advantages of using technology in offering Web-based courses and professional training are described and examples of the ongoing activities in this area are summarized. Focus, however, is placed on the development
Interpreting Electromagnetic Reflections In Glaciology
O. Eisen; U. Nixdorf; F. Wilhelms; D. Steinhage; H. Miller
Electromagnetic reflection (EMR) measurements are active remote sensing methods that have become a major tool for glaciological investigations. Although the basic pro- cesses are well understood, the unambiguous interpretation of EMR data, especially internal layering, still requires further information. The Antacrtic ice sheet provides a unique setting for investigating the relation between physicalchemical properties of ice and EMR data. Cold
Carbon onions for electromagnetic applications
S. Maksimenko; P. Kuzhir; G. Slepyan; V. Kuznetsov; O. Shenderova; A. Okotrub; L. G. Bulusheva; J. Macutkevic; P. Lambin
Electromagnetic (EM) absorption properties of a novel nanocarbon material - onion-like carbon (OLC) produced by annealing of detonation nanodiamonds (ND) in vacuum - have been studied in low-frequency, microwave and THz frequency ranges. It was proved experimentally that OLC EM absorption capacity can be optimized by varying the nanocarbon cluster size and ND annealing temperature so that effective EM coatings
Electromagnetic electron temperature anisotropy instabilities
NASA Technical Reports Server (NTRS)
Gary, S. P.; Madland, C. D.
This paper considers electromagnetic Vlasov instabilities driven by electron temperature anisotropies in a homogeneous, nonrelativistic magnetized plasma. Numerical solutions of the full linear dispersion equation for bi-Maxwellian distribution functions and instabilities propagating parallel to the magnetic field are presented. Parametric dependences of the maximum growth rates of the electron fire hose and whistler anisotropy instabilities are given.
Electromagnetic electron temperature anisotropy instabilities
NASA Astrophysics Data System (ADS)
Gary, S. P.; Madland, C. D.
This paper considers electromagnetic Vlasov instabilities driven by electron temperature anisotropies in a homogeneous, nonrelativistic magnetized plasma. Numerical solutions of the full linear dispersion equation for bi-Maxwellian distribution functions and instabilities propagating parallel to the magnetic field are presented. Parametric dependences of the maximum growth rates of the electron fire hose and whistler anisotropy instabilities are given.
Electromagnetic scattering from dielectric bodies
Tapan K. Sarkar; Ercument Arvas; Saila Ponnapalli
Far-field results obtained by two different methods are compared for the problem of electromagnetic scattering from dielectric objects. The two methods are the surface integral formulation, utilizing equivalent electric and magnetic surface currents, and the volume formulation, utilizing the equivalent electric polarization current. Triangular patches are used in the surface formulation and cubical cells are used in the volume formulation.
Electromagnetic calorimeter for Belle II
NASA Astrophysics Data System (ADS)
Belle-ECL; Aulchenko, V.; Bobrov, A.; Bondar, A.; Cheon, B. G.; Eidelman, S.; Epifanov, D.; Garmash, Yu; Goh, Y. M.; Kim, S. H.; Krokovny, P.; Kuzmin, A.; Lee, I. S.; Matvienko, D.; Miyabayashi, K.; Nakamura, I.; Shebalin, V.; Shwartz, B.; Unno, Y.; Usov, Yu; Vinokurova, A.; Vorobjev, V.; Zhilich, V.; Zhulanov, V.
The electromagnetic calorimeter of the BELLE II detector for experiments at Super B-factory SuperKEKB is briefly described. The project of the calorimeter upgrade to meet severe background conditions expected at the upgraded KEK B factory is presented.
Electromagnetic Levitation of a Disc
ERIC Educational Resources Information Center
Valle, R.; Neves, F.; de Andrade, R., Jr.; Stephan, R. M.
This paper presents a teaching experiment that explores the levitation of a disc of ferromagnetic material in the presence of the magnetic field produced by a single electromagnet. In comparison to the classical experiment of the levitation of a sphere, the main advantage of the proposed laboratory bench is that the uniform magnetic field…
Electromagnetic Design With Transformation Optics
Nathan B. Kundtz; David R. Smith; John B. Pendry
Transformation optics is an emerging technique for the design of advanced electromagnetic media. Transfor- mation optical devices exploit the form invariance of Maxwell's equations, allowing geometry to play the dominant role in the design process rather than traditional wave or ray optics. The use of coordinate transformations vastly eases the burden of design for a large class of devices, though
W. Sieber
Problems solved? Pulsar research must be considered - 35 years after the detection of pulsars - a mature science, where the basic questions have been raised and discussed. One would hope that many if not all generic and important problems have found some kind of answer and that scientific work can concentrate now on specific details requiring more in depth investigation. We know, however, that this picture is not true. Even well studied areas did in the past not always lead to a general accepted model and some were investigated at the beginning with enthusiasm but left behind. This paper will concentrate on one narrow topic, pulsar radio spectra. It is the attempt to work out, what features are now generally accepted, but also what features are still in discussion after so many years of pulsar research. In this sense the paper will enlighten in a personal view those aspects which are still under discussion.
NASA Astrophysics Data System (ADS)
Tomková, E.
Methods of TDS spectra analysis start usually from the Polanyi-Wigner desorption rate equation. The Redhead approximative solution of the equation can be rearranged into a reduced form in which it serves as an analytical expression for the desorption rate versus time or temperature. Fitting the analytical form to an experimental curve we can confirm or deny the invariability of kinetic parameters — a desorption energy Ed and a preexponential factor ?l — and determine their values. If the parameters depend on surface coverage ? the application of the reduced form allows us to determine their values at ??0 and ?? ?0 and estimate the dependence Ed( ?), ?(?) from a single TDS spectrum. The method proposed in this paper is valid for the first-order kinetics of desorption; for the estimation mentioned above an assumption is made that desorption sites are identical and that E d as well as ?l changes with ? monotonously.
611: Electromagnetic Theory Problem Sheet 5
Pope, Christopher
611: Electromagnetic Theory Problem Sheet 5 (1a) The Null Energy Condition on an energy = (k, 0, 0, k), show that the energy-momentum tensor Tµ = 1 4 Fµ F - 1 4µ F F (1) for electromagnetism if the equality kµ k Tµ = 0 is attained. (2) Show that the energy-momentum tensor for electromagnetism can
Course Outline Physics 433: Electromagnetism II
Course Outline Physics 433: Electromagnetism II Spring 2014 Prof. Keun Hyuk "Ken" Ahn 483 Tiernan of this course is on the elementary concepts of electromagnetic fields. Upon completion of the course, students are expected to be capable of using the Maxwell equations to calculate simple electromagnetic problems, ranging
611: Electromagnetic Theory Problem Sheet 5
Pope, Christopher
611: Electromagnetic Theory Problem Sheet 5 (1a) Show that the energy-momentum tensor for the electromagnetic field is tracefree, i.e. Tµ µ = 0. What would happen, in a spacetime dimension d = 4? (Assume) Show that the energy-momentum tensor for the electromagnetic field can be written as Tµ = 1 8 (Fµ F
611: Electromagnetic Theory Problem Sheet 5
Pope, Christopher
611: Electromagnetic Theory Problem Sheet 5 (1) Consider the expression for the electric field due · dS over a spherical surface that encloses the moving charge. (2a) Consider an electromagnetic wave density and the Poynting vector. (2c) Repeat the steps in (2a) and (2b) for an electromagnetic wave
Electromagnetic Formation Flight of Satellite Arrays
Electromagnetic Formation Flight of Satellite Arrays Daniel W. Kwon and David W. Miller February 2005 SSL # 2-05 #12;#12;Electromagnetic Formation Flight of Satellite Arrays By DANIEL W. KWON S;#12;Electromagnetic Formation Flight of Satellite Arrays by DANIEL W. KWON Submitted to the Department of Aeronautics
611: Electromagnetic Theory Problem Sheet 6
Pope, Christopher
611: Electromagnetic Theory Problem Sheet 6 (1) Consider the expression for the electric field due · dS over a spherical surface that encloses the moving charge. (2a) Consider an electromagnetic wave density and the Poynting vector. (2c) Repeat the steps in (2a) and (2b) for an electromagnetic wave
Electromagnetics from Simulation to Optimal Design
Lang, Annika
1 Electromagnetics from Simulation to Optimal Design Christian Hafner Laboratory for Electromagnetic Fields and Microwave Electronics (IFH) ETH Zurich (Switzerland) Lab: http://www.ifh.ee.ethz.ch COG 23, 2013 #12;2 IFH courses · Advanced engineering electromagnetics (Leuchtmann, start spring 2014
Electromagnetic Interrogation of Dielectric Materials 1
Electromagnetic Interrogation of Dielectric Materials 1 H.T. Banks M.W. Buksas Center for Research grant P200A40730. #12; Abstract We investigate time domain based electromagnetic inverse problems electromagnetic phenomenon. For our purposes, we categorize the materials and the models employed to describe them
Emission of Electromagnetic Radiation Upon Electric Stimulation
Karczmarek, Joanna
Emission of Electromagnetic Radiation Upon Electric Stimulation of Preserved Cucumis sativus of ElectromagneticEmission of Electromagnetic Radiation Upon ElectricRadiation Upon Electric Stimulation of PreservedStimulation-Pronged Electrical Cord · Electrical Tape · 2 Pins · Variac · Spectroscopes #12;How it all goes together
ABSORBING BOUNDARY CONDITIONS FOR ELECTROMAGNETIC WAVE PROPAGATION Xiaobing Feng y Abstract of the electromagnetic fields indi vidually. This boundary condition allows any wave motion generated within the domain, and the electromagnetic wave scattering related to antennas. Because of the limitations of both speed and memory
Electromagnetic Radiation REFERENCE: Remote Sensing of
Gilbes, Fernando
1 CHAPTER 2: Electromagnetic Radiation Principles REFERENCE: Remote Sensing of the Environment John Radiation Models To understand how electromagnetic radiation is created, how it propagates through space: · the wave model · the particle model Wave Model of Electromagnetic Radiation In the 1860s, James Clerk
Paris-Sud XI, Université de
293 JOSEPHSON DETECTORS OF MILLIMETER ELECTROMAGNETIC RADIATION V. A. KULIKOV, N. N. KURDJUMOV, G. 2014 The possibility of construction of high sensitive detectors of electromagnetic radiation is devoted to detectors of electromagnetic radiation in the upper millimeter range, designed for use
Electromagnetic Corrections in Staggered Chiral Perturbation Theory
Bernard, Claude
Electromagnetic Corrections in Staggered Chiral Perturbation Theory C. Bernard and E.D. Freeland perturbation theory including electromagnetism, and discuss the extent to which quenched-photon simulations can-lat]17Nov2010 #12;Electromagnetic Corrections in Staggered Chiral Perturbation Theory E.D. Freeland 1
Acousto-electromagnetic Tomography Habib Ammari
Garnier, Josselin
Acousto-electromagnetic Tomography Habib Ammari Emmanuel Bossy Josselin Garnier§ Laurent Seppecher June 28, 2012 Abstract The aim of this paper is to develop a mathematical framework for acousto-electromagnetic tomography and to introduce an efficient reconstruction algorithm. In electromagnetic wave imaging
Physics 4: Introductory Physics Electromagnetism and Light
Fygenson, Deborah Kuchnir
loop; electromagnets vs. permanent magnets; Ampere's Law and "circulation"; magnetic materials 28Physics 4: Introductory Physics Electromagnetism and Light Professor Jeffrey D. Richman Department: Electromagnetism and Light Welcome to Physics 4! What is your goal in life? If it is to become an engineer
A technology that squeezes electromagnetic waves
Atwater, Harry
A technology that squeezes electromagnetic waves into minuscule structures may yield a new and manipulate visible light and other electromagnetic waves--could someday replace electronic circuits in micro plasmons with the same frequency as the outside electromagnetic waves but with a much shorter wavelength
Results of 2007 test beam of AMS-02 Electromagnetic Calorimeter
NASA Astrophysics Data System (ADS)
Falco, Stefano Di
The AMS-02 experiment will be delivered by the Space Shuttle Discovery to the ISS in summer 2010. The main goals of the experiment are search for antimatter and dark matter, high precision measurement of charged cosmic ray spectra and fluxes and study of gamma rays, in the GeV to TeV energy range. In AMS-02 the Electromagnetic Calorimeter (ECAL) is required to measure e+,e- and gamma energy and to discriminate electromagnetic showers from hadronic cascades. ECAL is based on a lead/scintillating fiber sandwich, providing a 3D imaging reconstruction of the showers. The electronics equipping the detector has low power consumption, low noise, large dynamic range readout and full double redundancy. The calorimeter successfully got through several space qualification tests concerning the mechanical and thermal stability, the electromagnetic compatibility and radiation hardness. The ECAL Flight Model was calibrated during Summer 2007 in a test beam at CERN, using 6-250 GeV electron and proton beams: angular and energy resolutions, obtained from these data, are reported.
Power Spectra to 1% Accuracy between Dynamical Dark Energy Cosmologies
Matthew J. Francis; Geraint F. Lewis; Eric V. Linder
For dynamical dark energy cosmologies we carry out a series of N-body gravitational simulations, achieving percent level accuracy in the relative mass power spectra at any redshift. Such accuracy in the power spectrum is necessary for next generation cosmological mass probes. Our matching procedure reproduces the CMB distance to last scattering and delivers subpercent level power spectra at z=0 and z~3. We discuss the physical implications for probing dark energy with surveys of large scale structure.
Electromagnetics for Detecting Shallow Tunnels
NASA Astrophysics Data System (ADS)
Won, I.
Detecting tunnels by geophysical means, even very shallow ones, has been difficult, to say the least. Despite heavy R&D funding from the military since the early 70s, geophysicists have not produced tools that are simple and practical enough to meet the military needs. The initial interest and R&D funding on the subject perhaps started with the Vietcong tunnels in the 60s. Tunnels in the Korean DMZ, first found in the mid 70s, sharply escalated the R&D spending. During the 90s, covert tunnels along the US-Mexico border have kept the topic alive but at a minimal funding level. Most recent interest appears to be in the terrorism-related shallow tunnels, more or less anywhere in the regions of conflict. Despite the longstanding effort in the geophysical community under heavy public funding, there is a dearth of success stories where geophysicists can actually claim to have found hitherto unknown tunnels. For instance, geophysics has not discovered a single tunnel in Vietnam or in Korea! All tunnels across the Korean DMZ were found from human intelligence. The same is true to all illicit tunnels found along the southwestern border. The tunnels under discussion are clandestine, which implies that the people who built them do not wish others to succeed in finding them. The place around the tunnel, therefore, may not be the friendliest venue for surveyors to linger around. The situation requires tools that are fast, little noticeable, and hardly intrusive. Many geophysical sensors that require ground contacts, such as geophones and electrodes that are connected by a myriad of cables, may not be ideal in this situation. On the other hand, a sensor that can be carried by vehicle without stopping, and is nothing obviously noticeable to bystanders, could be much more acceptable. Working at unfriendly environment also requires forgoing our usual practices where we collect data leisurely and make pretty maps later. To be useful, geophysical tools must be able to process observed data and translate them into actionable results. They may in forms of audio (similar to the beeper of a landmine detector), strip chart, or even a 2D graphic display on a computer screen. In short, the tool must be able to declare a contact, audibly or graphically, in real time or shortly thereafter. In summary, we have two questions here. The first one is if any of the available geophysical tools can detect tunnels. If the answer is yes, then the next question is if any of them are able to perform fast in an unfriendly environment. Electromagnetic sensors may be able to meet the operational requirements: under what circumstances it can find tunnels would be another outstanding question.
Gold nanoparticle dimer plasmonics: finite element method calculations of the electromagnetic enhancement to surface-enhanced Raman spectroscopy
Jeffrey M. McMahon; Anne-Isabelle Henry; Kristin L. Wustholz; Michael J. Natan; R. Griffith Freeman; Richard P. Van Duyne; George C. Schatz
Finite element method calculations were carried out to determine extinction spectra and the electromagnetic (EM) contributions\\u000a to surface-enhanced Raman spectroscopy (SERS) for 90-nm Au nanoparticle dimers modeled after experimental nanotags. The calculations\\u000a revealed that the EM properties depend significantly on the junction region, specifically the distance between the nanoparticles\\u000a for spacings of less than 1 nm. For extinction spectra, spacings below
Technology Transfer Automated Retrieval System (TEKTRAN)
Infrared spectra were calculated for the low energy geometry optimized structures of glucose and all of its epimers, at B3LYP/6-311++G** level of theory. Calculations were performed both in vacuo and using the COSMO solvation method. Frequencies, zero point energies, enthalpies, entropies, and rel...
Novel electromagnetic materials from functionalized structures
NASA Astrophysics Data System (ADS)
Xiao, Xiao
Materials, exhibiting the novel electromagnetic responses those may not be found in nature, have the potential to manipulate the electromagnetic field passing through them. Consequently, these materials promise a number of applications, such as highly sensitive sensor, superlenses, high-gain antennas and electromagnetic wave cloaking. In the literature we would investigate various electromagnetic materials composed from functionalized structures (components). The novel electromagnetic materials can be photonic crystals, which are composed of the periodic dielectric or metallic structures. The propagation of the electromagnetic wave in photonic crystals is affected in the same way as the electrons propagating in the periodic potential in solid. We demonstrated that the photonic crystals can be used as a tool to tune the birefringence of the electromagnetic field. Metamaterials, which are composed of the artificial structures exhibiting strong local resonances, are also a kind of novel electromagnetic materials. The strong local resonance can squeeze the wavelength of the incoming electromagnetic field to the subwavelength region (i.e. superlenses) and revise the effective electromagnetic response of the materials (i.e. the negative indexes). For metamaterials we focus on the Plasmonic metamaterials in the thesis: we would show that these materials could be used to guide electromagnetic wave or introduce various kinds of extraordinary transmissions, both of which, of course, are achieved at subwavelength region. Moreover, the novel electromagnetic materials can be even the topological insulators, whose non-trivial electronic surface states can have extraordinary responses under the electromagnetic field. These non-trivial quantum hall surface states can introduce the mode conversion between different electromagnetic modes on the surfaces of the topological insulators and thus modify the propagation properties of the electromagnetic field through them. We would demonstrate that the non-trivial surface states of the topological insulators could modify the coherence of the thermal radiation from them.
Observation of Ground Level Muons at Two Geomagnetic Locations
NASA Astrophysics Data System (ADS)
Kremer, Jens
Two extensive measurements of ground level muons were performed with the NMSU-WIZARD/CAPRICE magnet spectrometer at Lynn Lake, Manitoba, Canada and Fort Sumner, New Mexico, USA, in July 1994 and spring 1997, respectively. The spectrometer was equipped with a superconducting magnet, a time-of-flight system, an electromagnetic calorimeter and a Ring Imaging Cherenkov (RICH) detector. Two different versions of the RICH were used: one with a solid NaF radiator in 1994 and one with a gaseous C4 F10 radiator in 1997. Both the muon spectrum and the + to , ratio are presented in the momentum range from 200 MeV/c to 120 GeV/c for the two different geomagnetic locations. The spectra are compared with previous experimental results. The data show latitude dependent geomagnetic effects.
Cross-spectral purity of electromagnetic fields.
Hassinen, Timo; Tervo, Jani; Friberg, Ari T
We extend Mandel's scalar-wave concept of cross-spectral purity to electromagnetic fields. We show that in the electromagnetic case, assumptions similar to the scalar cross-spectral purity lead to a reduction formula, analogous with the one introduced by Mandel. We also derive a condition that shows that the absolute value of the normalized zeroth two-point Stokes parameter of two cross-spectrally pure electromagnetic fields is the same for every frequency component of the field. In analogy with the scalar theory we further introduce a measure of the cross-spectral purity of two electromagnetic fields, namely, the degree of electromagnetic cross-spectral purity. PMID:20016640
Current sheet canting in pulsed electromagnetic accelerators
NASA Astrophysics Data System (ADS)
Markusic, Thomas Edward
The phenomenon of current sheet canting in pulsed electromagnetic accelerators is the departure of the plasma sheet that carries the current from a plane that is perpendicular to the electrodes to one that is skewed, or tipped. Review of pulsed electromagnetic accelerator literature reveals that current sheet canting is a ubiquitous phenomenon---occurring in all of the standard accelerator geometries. Developing an understanding of current sheet canting is important because it can detract from the propellant sweeping capabilities of current sheets and, hence, negatively impact the overall efficiency of pulsed electromagnetic accelerators. In the present study, photographic, magnetic, and laser-interferometric diagnostics were implemented to measure the current sheet canting angle in an experimental pulsed electromagnetic accelerator. Eight different propellants (hydrogen, deuterium, helium, neon, argon, krypton, xenon, and methane) were tested in a rectangular-geometry accelerator, at pressure levels ranging from 75--400 mTorr. The photographic, magnetic, and interferometric diagnostics were used to infer the spatial configuration of the current sheet by measuring its optical emission, current density, and electron density, respectively. The three techniques showed quantitative agreement. Additionally, emission spectroscopy was used to measure the electron temperature in the current sheet plasma. The canting angle was found to increase with the atomic mass of the propellant and the current sheet was always found to tilt such that the anode current attachment leads the cathode attachment. Lighter atoms were observed to yield less canting (the measured angles ranged from approximately 10° for hydrogen to 70° for xenon). Hydrogen, deuterium, and methane were found to exhibit the peculiar, and possibly beneficial, property of having reduced current sheet canting at the highest pressure level. The experimental results also motivated further analysis of the data, and led to the conclusion that current sheet canting is a natural consequence of the manner in which current is conducted in pulsed electromagnetic accelerators. It is postulated that depletion of plasma near the anode, which results from axial density gradient induced diamagnetic drift, occurs during the early stages of the discharge, creating a density gradient normal to the anode, with characteristic length on the order of the ion skin depth. Rapid penetration of the magnetic field through this region ensues, due to Hall effect, leading to a canted current front ahead of the initial current conduction channel. In this model, once the current sheet reaches appreciable speeds, entrainment of stationary propellant replenishes plasma in the anode region, inhibiting further Hall-convective transport of the magnetic field; however, the previously established tilted current sheet remains at a fairly constant canting angle for the remainder of the discharge cycle, exerting a transverse J x B force which drives plasma toward the cathode and accumulates it there. This proposed sequence of events has been incorporated into a phenomenological model. The model is shown to give quantitative agreement with the experimentally measured canting angle mass dependence trends.
Some Wave Equations for Electromagnetism and Gravitation
Zi-Hua Weng
The paper studies the inferences of wave equations for electromagnetic fields when there are gravitational fields at the same time. In the description with the algebra of octonions, the inferences of wave equations are identical with that in conventional electromagnetic theory with vector terminology. By means of the octonion exponential function, we can draw out that the electromagnetic waves are transverse waves in a vacuum, and rephrase the law of reflection, Snell's law, Fresnel formula, and total internal reflection etc. The study claims that the theoretical results of wave equations for electromagnetic strength keep unchanged in the case for coexistence of gravitational and electromagnetic fields. Meanwhile the electric and magnetic components of electromagnetic waves can not be determined simultaneously in electromagnetic fields.
4 -STELLAR SPECTRA The spectra of most stars are approximately
Sitko, Michael L.
classification criteria have been developed. For stars heavily obscured by dust, near-IR (1-2.5 µm) features1 4 - STELLAR SPECTRA The spectra of most stars are approximately blackbodies. The presence features indicated the luminosity L of the star, and Roman numerals were appended to indicate
Electromagnetic Counterparts to Black Hole Mergers
NASA Technical Reports Server (NTRS)
Schnittman, Jeremy D.
During the final moments of a binary black hole (BH) merger, the gravitational wave (GW) luminosity of the system is greater than the combined electromagnetic (EM) output of the entire observable universe. However, the extremely weak coupling between GWs and ordinary matter makes these waves very difficult to detect directly. Fortunately, the inspirating BH system will interact strongly-on a purely Newtonian level-with any surrounding material in the host galaxy, and this matter can in turn produce unique EM signals detectable at Earth. By identifying EM counterparts to GW sources, we will be able to study the host environments of the merging BHs, in turn greatly expanding the scientific yield of a mission like LISA. Here we present a comprehensive review of the recent literature on the subject of EM counterparts, as well as a discussion of the theoretical and observational advances required to fully realize the scientific potential of the field.
Research instrumentation for tornado electromagnetics emissions detection
NASA Technical Reports Server (NTRS)
Jenkins, H. H.; Wilson, C. S.
Instrumentation for receiving, processing, and recording HF/VHF electromagnetic emissions from severe weather activity is described. Both airborne and ground-based instrumentation units are described on system and subsystem levels. Design considerations, design decisions, and the rationale behind the decisions are given. Performance characteristics are summarized and recommendations for improvements are given. The objectives, procedures, and test results of the following are presented: (1) airborne flight test in the Midwest U.S.A. (Spring 1975) and at the Kennedy Space Center, Florida (Summer 1975); (2) ground-based data collected in North Georgia (Summer/Fall 1975); and (3) airborne flight test in the Midwest (late Spring 1976) and at the Kennedy Space Center, Florida (Summer 1976). The Midwest tests concentrated on severe weather with tornadic activity; the Florida and Georgia tests monitored air mass convective thunderstorm characteristics. Supporting ground truth data from weather radars and sferics DF nets are described.
SpectraFactory.net: A Database of Molecular Model Spectra
NASA Astrophysics Data System (ADS)
Cami, J.; van Malderen, R.; Markwick, A. J.
We present a homogeneous database of synthetic molecular absorption and emission spectra from the optical to mm wavelengths for a large range of temperatures and column densities relevant for various astrophysical purposes, but in particular for the analysis, identification, and first-order analysis of molecular bands in spectroscopic observations. All spectra are calculated in the LTE limit from several molecular line lists, and are presented at various spectral resolving powers corresponding to several specific instrument simulations. The database is available online at http://www.spectrafactory.net, where users can freely browse, search, display, and download the spectra. We describe how additional model spectra can be requested for (automatic) calculation and inclusion. The database already contains over half a million model spectra for 39 molecules (96 different isotopologues) over the wavelength range 350 nm-3 mm (?3-30000 cm-1).
Effects of high-frequency electromagnetic fields emitted from card readers of access control systems on electronic pocket dosimeters
Shizuhiko Deji; Kunihide Nishizawa
High-frequency electromagnetic fields in the 120kHz band emitted from card readers for access control systems caused abnormally high doses on electronic pocket dosimeters (EPDs). All EPDs recovered their normal performance by resetting after the exposure ceased. The electric and magnetic immunity levels of the EPDs were estimated by using the distances needed to prevent electromagnetic interference.
Falling Magnets and Electromagnetic Braking
NASA Astrophysics Data System (ADS)
Culbreath, Christopher; Palffy-Muhoray, Peter
The slow fall of a rare earth magnet through a copper pipe is a striking example of electromagnetic braking; this remarkable phenomenon has been the subject of a number of scientific paper s [1, 2]. In a pipe having radius R and wall thickness D, the terminal velocity of the falling magnet is proportional to (R?4)/D. It is interesting to ask what happens in the limit as D becomes very large. We report our experimental observations and theoretical predictions of the dependence of the terminal velocity on pipe radius R for large D. [1] Y. Levin, F.L. da Silveira, and F.B. Rizzato, ``Electromagnetic braking: A simple quantitative model''. American Journal of Physics, 74(9): p. 815-817 (2006). [2] J.A. Pelesko, M. Cesky, and S. Huertas, Lenz's law and dimensional analysis. American Journal of Physics, 3(1): p. 37-39. 2005.
The hidden geometry of electromagnetism
Hadad, Yaron; Kaminer, Ido; Elitzur, Avshalom C
Nearly all field theories suffer from singularities when particles are introduced. This is true in both classical and quantum physics. Classical field singularities result in the notorious self-force problem, where it is unknown how the dynamics of a particle change when the particle interacts with its own (self) field. Self-force is a pressing issue and an active research topic in gravitational phenomena, as well as a source of controversies in classical electromagnetism. In this work, we study a hidden geometrical structure manifested by the electromagnetic field-lines that has the potential of eliminating all singularities from classical electrodynamics. We explore preliminary results towards a consistent way of treating both self- and external fields.
The hidden geometry of electromagnetism
Yaron Hadad; Eliahu Cohen; Ido Kaminer; Avshalom C. Elitzur
Nearly all field theories suffer from singularities when particles are introduced. This is true in both classical and quantum physics. Classical field singularities result in the notorious self-force problem, where it is unknown how the dynamics of a particle change when the particle interacts with its own (self) field. Self-force is a pressing issue and an active research topic in gravitational phenomena, as well as a source of controversies in classical electromagnetism. In this work, we study a hidden geometrical structure manifested by the electromagnetic field-lines that has the potential of eliminating all singularities from classical electrodynamics. We explore preliminary results towards a consistent way of treating both self- and external fields.
Genetic algorithms in engineering electromagnetics
J. Michael Johnson; V. Rahmat-Samii
This paper presents a tutorial and overview of genetic algorithms for electromagnetic optimization. Genetic-algorithm (GA) optimizers are robust, stochastic search methods modeled on the concepts of natural selection and evolution. The relationship between traditional optimization techniques and the GA is discussed. Step-by-step implementation aspects of the GA are detailed, through an example with the objective of providing useful guidelines for
Electromagnetic radiation produces frame dragging
NASA Astrophysics Data System (ADS)
Herrera, L.; Barreto, W.
It is shown that for a generic electrovacuum spacetime, electromagnetic radiation produces vorticity of worldlines of observers in a Bondi-Sachs frame. Such an effect (and the ensuing gyroscope precession with respect to the lattice) which is a reminiscence of generation of vorticity by gravitational radiation, may be linked to the nonvanishing of components of the Poynting and the super-Poynting vectors on the planes othogonal to the vorticity vector. The possible observational relevance of such an effect is commented upon.
Dark Energy, Gravitation and Electromagnetism
B. G. Sidharth
In the context of the fact that the existence of dark energy causing the accelerated expansion of the universe has been confirmed by the WMAP and the Sloan Digital Sky Survey, we re-examine gravitation itself, starting with the formulation of Sakharov and show that it is possible to obtain gravitation in terms of the electromagnetic charge of elementary particles, once the ZPF and its effects at the Compton scale are taken into account.
Localized transmission of electromagnetic energy
Richard W. Ziolkowski
Novel electromagnetic directed-energy pulse train (EDEPT) solutions of Maxwell's equations have been obtained. One particular solution, the modified-power-spectrum (MPS) pulse, will be described in detail. EDEPT's such as the MPS pulses, can be tailored to give localized energy transmission along a specified direction in space that is significantly improved over conventional diffraction-limited beams. Moreover, they represent fields that recover their
Pulsed power for electromagnetic launching
Cowan, M
There are system advantages to producing power for electromagnetic propulsion by real-time generation rather than by a sequence of generation-storage-switching. The best type of generator for this purpose is the flux compression generator. Different types of flux compression generator which have been developed at Sandia National Laboratories are reviewed and their applications to electric launching are discussed. New experimental facilities for producing more powerful generators are described and cost comparisons are made.
Electromagnetic Calorimeter for HADES Experiment
NASA Astrophysics Data System (ADS)
Rodríguez-Ramos, P.; Chlad, L.; Epple, E.; Fabbietti, L.; Galatyuk, T.; Golubeva, M.; Guber, F.; Hlavá?, S.; Ivashkin, A.; Kajetanowic, M.; Kardan, B.; Koenig, W.; Korcyl, G.; Kugler, A.; Lapidus, K.; Linev, S.; Lisowski, E.; Neiser, A.; Ott, O.; Otte, O.; Pethukov, O.; Pietraszko, J.; Reshetin, A.; Rost, A.; Salabura, P.; Sobolev, Y. G.; Svoboda, O.; Thomas, A.; Tlusty, P.; Traxler, M.
Electromagnetic calorimeter (ECAL) is being developed to complement dilepton spectrometer HADES. ECAL will enable the HADES@FAIR experiment to measure data on neutral meson production in heavy ion collisions at the energy range of 2-10 AGeV on the beam of future accelerator SIS100@FAIR. We will report results of the last beam test with quasi-monoenergetic photons carried out in MAMI facility at Johannes Gutenberg Universität Mainz.
Laminated electromagnetic pump stator core
Fanning, Alan W. (San Jose, CA)
A stator core for an electromagnetic pump includes a plurality of circumferentially abutting tapered laminations extending radially outwardly from a centerline axis to collectively define a radially inner bore and a radially outer circumference. Each of the laminations includes radially inner and outer edges and has a thickness increasing from the inner edge toward the outer edge to provide a substantially continuous path adjacent the circumference.
Laminated electromagnetic pump stator core
Fanning, A.W.
A stator core for an electromagnetic pump includes a plurality of circumferentially abutting tapered laminations extending radially outwardly from a centerline axis to collectively define a radially inner bore and a radially outer circumference. Each of the laminations includes radially inner and outer edges and has a thickness increasing from the inner edge toward the outer edge to provide a substantially continuous path adjacent the circumference. This pump is used in nuclear fission reactors. 19 figs.
Electromagnetic brake/clutch device
NASA Astrophysics Data System (ADS)
Vranish, John M.
An electromagnetic brake/clutch device includes a drive shaft supported by at least one bearing for transmitting torque, a housing, affixed to prevent its rotation, surrounding the drive shaft, and an electromagnetically activated device within the housing to selectively prevent and allow rotation of the drive shaft. The electromagnetically activated device includes a plurality of cammed rollers to prevent counter-clockwise rotation of the drive shaft. The drive shaft includes a circumferential disk and the housing includes a reaction ring for engagement with the plurality of cammed rollers. The plurality of cammed rollers are released from engagement with the circumferential disk and the reaction ring by a plurality of tripping mechanisms within the housing. The tripping action uses the locking force to act as a release force merely by changing the boundary conditions of the roller interface angles. The tripping mechanisms include trippers for disengaging the plurality of cammed rollers and an anvil shaped portion for providing lateral movement of the trippers. The plurality of cammed rollers is preloaded to engagement with the circumferential disk and reaction ring by a spring, and is located with respect to an adjacent tripping mechanism with another spring.
Electromagnetism on anisotropic fractal media
NASA Astrophysics Data System (ADS)
Ostoja-Starzewski, Martin
Basic equations of electromagnetic fields in anisotropic fractal media are obtained using a dimensional regularization approach. First, a formulation based on product measures is shown to satisfy the four basic identities of the vector calculus. This allows a generalization of the Green-Gauss and Stokes theorems as well as the charge conservation equation on anisotropic fractals. Then, pursuing the conceptual approach, we derive the Faraday and Ampčre laws for such fractal media, which, along with two auxiliary null-divergence conditions, effectively give the modified Maxwell equations. Proceeding on a separate track, we employ a variational principle for electromagnetic fields, appropriately adapted to fractal media, so as to independently derive the same forms of these two laws. It is next found that the parabolic (for a conducting medium) and the hyperbolic (for a dielectric medium) equations involve modified gradient operators, while the Poynting vector has the same form as in the non-fractal case. Finally, Maxwell's electromagnetic stress tensor is reformulated for fractal systems. In all the cases, the derived equations for fractal media depend explicitly on fractal dimensions in three different directions and reduce to conventional forms for continuous media with Euclidean geometries upon setting these each of dimensions equal to unity.
Inclusive Jet Spectra in p-Pb Collisions at ALICE
Megan Connors; for the ALICE Collaboration
Jet suppression has been observed in central heavy ion collisions. This suppression is attributed to partonic energy loss in the Quark Gluon Plasma (QGP) formed in such collisions. However, this measurement is influenced by all stages of the collision. It is expected that in p-Pb collisions similar initial conditions occur as in Pb-Pb collisions without creating a QGP, allowing modification to the jet spectra due to cold nuclear matter effects to be quantified. Inclusive jet spectra in p-Pb collisions at $\\sqrt{s_{\\rm NN}} = 5.02$ TeV measured by ALICE are presented. Jets are reconstructed via the anti-k$_{\\rm T}$ algorithm with different resolution parameters by combining charged tracks measured in the ALICE tracking system with the neutral energy deposited in the electromagnetic calorimeter. The jet spectra can be used to determine a nuclear modification factor $R_{\\rm pPb}$ while the jet profile in p-Pb is studied by dividing spectra measured with different resolution parameters and comparing to the same ratio measured in pp collisions.
V-type electromagnetically induced transparency and saturation effect at the gas-solid interface
Meng, Tengfei; Ji, Zhonghua; Su, Dianqiang; Xiao, Liantuan; Jia, Suotang
We theoretically study electromagnetically induced transparency (EIT) in reflection spectra of V-type system at the gas-solid interface. In addition to a narrow dip arising from the EIT effect, we find the other particular saturation effect induced by pump field, which does not exist in $\\Lambda$ or $\\Xi$ -type system reflection spectra. The saturation effect only induces an intensity decrement in the reflection spectra, and there is no influence on the narrow dip arising from the EIT effect. We detailedly calculate and analyze the dependence of V-type system reflection spectra on probe field intensity, pump field intensity, coherent decay rate, and the initial population after the collision between atoms and the interface.
Projecting Spectra for Classroom Investigations.
ERIC Educational Resources Information Center
Sadler, Philip
Describes an inexpensive spectrum projector that makes high-dispersion, high-efficiency diffraction gratings using a holographic process. Discusses classroom applications such as transmission spectra, absorption spectra, reflection characteristics of materials, color mixing, florescence and phosphorescence, and break up spectral colors. (MDH)
Two components in meteor spectra
Jiri Borovicka
Through an analysis of fireball spectra it was found that meteor heads consist of two parts with quite different temperatures. The spectra of both parts can be fitted with a simple thermal equilibrium model. The temperature of the main spectrum is about 4000 K, and that of the second spectrum is about 10,000 K. There is little evidence for a
Interaction of electromagnetic and acoustic waves in a stochastic atmosphere
NASA Technical Reports Server (NTRS)
Bhatnagar, N.; Peterson, A. M.
In the Stanford radio acoustic sounding system (RASS) an electromagnetic signal is made to scatter from a moving acoustic pulse train. Under a Bragg-scatter condition maximum electromagnetic scattering occurs. The scattered radio signal contains temperature and wind information as a function of the acoustic-pulse position. In this investigation RASS performance is assessed in an atmosphere characterized by the presence of turbulence and mean atmospheric parameters. The only assumption made is that the electromagnetic wave is not affected by stochastic perturbations in the atmosphere. It is concluded that the received radio signal depends strongly on the intensity of turbulence for altitudes of the acoustic pulse greater than the coherence length of propagation. The effect of mean vertical wind and mean temperature on the strength of the received signal is also demonstrated to be insignificant. Mean horizontal winds, however, shift the focus of the reflected electromagnetic energy from its origin, resulting in a decrease in received signal level when a monostatic radio-frequency (RF) system is used. For a bistatic radar configuration with space diversified receiving antennas, the shifting of the acoustic pulse makes possible the remote measurement of the horizontal wind component.
Geant4 electromagnetic physics updates for space radiation effects simulation
NASA Astrophysics Data System (ADS)
Ivantchenko, Anton; Nieminen, Petteri; Incerti, Sebastien; Santin, Giovanni; Ivantchenko, Vladimir; Grichine, Vladimir; Allison, John; Karamitos, Mathiew
The Geant4 toolkit is used in many applications including space science studies. The new Geant4 version 10.0 released in December 2013 includes a major revision of the toolkit and offers multi-threaded mode for event level parallelism. At the same time, Geant4 electromagnetic and hadronic physics sub-libraries have been significantly updated. In order to validate the new and updated models Geant4 verification tests and benchmarks were extended. Part of these developments was sponsored by the European Space Agency in the context of research aimed at modelling radiation biological end effects. In this work, we present an overview of results of several benchmarks for electromagnetic physics models relevant to space science. For electromagnetic physics, recently Compton scattering, photoelectric effect, and Rayleigh scattering models have been improved and extended down to lower energies. Models of ionization and fluctuations have also been improved; special micro-dosimetry models for Silicon and liquid water were introduced; the main multiple scattering model was consolidated; and the atomic de-excitation module has been made available to all models. As a result, Geant4 predictions for space radiation effects obtained with different Physics Lists are in better agreement with the benchmark data than previous Geant4 versions. Here we present results of electromagnetic tests and models comparison in the energy interval 10 eV - 10 MeV.
Propagation of terahertz electromagnetic wave in plasma with inhomogeneous collision frequency
Tian, Yuan; Han, YiPing; Ling, YingJie [School of Physics and Optoelectronic Engineering, Xidian University, Xi'an 710071 (China)] [School of Physics and Optoelectronic Engineering, Xidian University, Xi'an 710071 (China); Ai, Xia [National Laboratory of Science and Technology on Antennas and Microwaves Xidian University, Xi'an 710071 (China)] [National Laboratory of Science and Technology on Antennas and Microwaves Xidian University, Xi'an 710071 (China)
In this paper, we investigate the absorption spectra of terahertz electromagnetic wave in plasma with inhomogeneous collision frequency. Profiles are introduced to describe the non-uniformity of collision frequency. It is interesting to find that when the plasma is collision frequency inhomogeneous, the absorption spectrum would decreases faster than that in uniform plasma. And the rate of decreasing would be different when the profile changes. Two parameters are set up to predict how the profiles affect the absorption spectra. Furthermore, the effects of electron density are also considered.
Photon-graviton mixing in an electromagnetic field
F. Bastianelli; U. Nucamendi; C. Schubert; V. M. Villanueva
Einstein-Maxwell theory implies the mixing of photons with gravitons in an external electromagnetic field. This process and its possible observable consequences have been studied at tree level for many years. We use the worldline formalism for obtaining an exact integral representation for the one-loop corrections to this amplitude due to scalars and fermions. We study the structure of this amplitude, and obtain exact expressions for various limiting cases.
Electromagnetic Effects in SDF Explosions
Reichenbach, H; Neuwald, P; Kuhl, A L
The notion of high ion and electron concentrations in the detonation of aluminized explosive mixtures has aroused some interest in electro-magnetic effects that the SDF charges might generate when detonated. Motivated by this interest we have started to investigate whether significant electro-magnetic effects show up in our small-scale experiments. However, the design of instrumentation for this purpose is far from straightforward, since there are a number of open questions. Thus the main aim of the feasibility tests is to find - if possible - a simple and reliable method that can be used as a diagnostic tool for electro-magnetic effects. SDF charges with a 0.5-g PETN booster and a filling of 1 g aluminum flakes have been investigated in three barometric bomb calorimeters with volumes ranging from 6.3 l to of 6.6 l. Though similar in volume, the barometric bombs differed in the length-to-diameter ratio. The tests were carried out with the bombs filled with either air or nitrogen at ambient pressure. The comparison of the test in air to those in nitrogen shows that the combustion of TNT detonation products or aluminum generates a substantial increase of the quasi-steady overpressure in the bombs. Repeated tests in the same configuration resulted in some scatter of the experimental results. The most likely reason is that the aluminum combustion in most or all cases is incomplete and that the amount of aluminum actually burned varies from test to test. The mass fraction burned apparently decreases with increasing aspect ratio L/D. Thus an L/D-ratio of about 1 is optimal for the performance of shock-dispersed-fuel combustion. However, at an L/D-ratio of about 5 the combustion still yields appreciable overpressure in excess of the detonation. For a multi-burst scenario in a tunnel environment with a number of SDF charges distributed along a tunnel section a spacing of 5 tunnel diameter and a fuel-specific volume of around 7 l/g might provide an acceptable compromise between optimizing the combustion performance and keeping the number of elementary charges low. Further tests in a barometric bomb calorimeter of 21.2 l volume were performed with four types of aluminum. The mass fraction burned in this case appeared to depend on the morphology of the aluminum particles. Flake aluminum exhibited a better performance than granulated aluminum with particle sizes ranging from below 25 {micro}m to 125 {micro}m for the coarsest material. In addition, a feasibility study on electro-magnetic effects from SDF charges detonated in a tunnel has been performed. A method was developed to measure the local, unsteady electro-conductivity in the detonation/combustion products cloud. This method proved to yield reproducible results. A variety of methods were tested with regard to probing electro-magnetic pulses from the detonation of SDF charges. The results showed little reproducibility and were small compared to the effect from pulsed high voltage discharges of comparatively small energy (around 32 J). Thus either no significant electromagnetic pulse is generated in our small-scale tests or the tested techniques have to be discarded as too insensitive or too limited in bandwidth to detect possibly very high frequency electro-magnetic disturbances.
An Interactive Gallery of Planetary Nebula Spectra
NASA Astrophysics Data System (ADS)
Kwitter, K. B.; Henry, R. B. C.
We have created a website containing high-quality moderate-resolution spectra of 88 planetary nebulae (PNe) from 3600 to 9600 Ĺ, obtained at KPNO and CTIO. Spectra are displayed in a zoomable window, and there are templates available that show wavelength and ion identifications. In addition to the spectra themselves, the website also contains a brief discussion of PNe as astronomical objects and as contributors to our understanding of stellar evolution, and a table with atlas information for each object along with a link to an image. This table can be re-ordered by object name, galactic or equatorial coordinates, distance from the sun, the galactic center, or the galactic plane. We envision that this website, which concentrates a large amount of data in one place, will be of interest to a variety of users. PN researchers might need to check the spectrum of a particular object of interest; the non-specialist astronomer might simply be interested in perusing such a collection of spectra; and finally, teachers of introductory astronomy can use this database to illustrate basic principles of atomic physics and radiation. To encourage such use, we have written two simple exercises at a basic level to introduce beginning astronomy students to the wealth of information that PN spectra contain. We are grateful to Adam Wang of the Williams College OIT and to his summer student teams who worked on various apects of the implementation of this website. This work has been supported by NSF grant AST-9819123 and by Williams College and the University of Oklahoma.
Hidden relationship between the electrical conductivity and the Mn 2p core-level photoemission spectra in La{sub 1-x}Sr{sub x}MnO{sub 3}
Hishida, T.; Ohbayashi, K. [NGK SPARK PLUG CO., LTD., 2808 Iwasaki, Komaki, Aichi 485-8510 (Japan); Saitoh, T. [Department of Applied Physics, Tokyo University of Science, Shinjuku, Tokyo 162-8601 (Japan)
Core-level electronic structure of La{sub 1-x}Sr{sub x}MnO{sub 3} has been studied by x-ray photoemission spectroscopy (XPS). We first report, by the conventional XPS, the well-screened shoulder structure in Mn 2p{sub 3/2} peak, which had been observed only by hard x-ray photoemission spectroscopy so far. Multiple-peak analysis revealed that the Mn{sup 4+} spectral weight was not proportional to the nominal hole concentration x, indicating that a simple Mn{sup 3+}/Mn{sup 4+} intensity ratio analysis may result in a wrong quantitative elemental analysis. Considerable weight of the shoulder at x = 0.0 and the fact that the shoulder weight was even slightly going down from x = 0.2 to 0.4 were not compatible with the idea that this weight simply represents the metallic behavior. Further analysis found that the whole Mn 2p{sub 3/2} peak can be decomposed into four portions, the Mn{sup 4+}, the (nominal) Mn{sup 3+}, the shoulder, and the other spectral weight located almost at the Mn{sup 3+} location. We concluded that this weight represents the well-screened final state at Mn{sup 4+} sites, whereas the shoulder is known as that of the Mn{sup 3+} states. We found that the sum of these two spectral weight has an empirical relationship to the conductivity evolution with x.
Analysis of spectra using correlation functions
NASA Technical Reports Server (NTRS)
Beer, Reinhard; Norton, Robert H.
A novel method is presented for the quantitative analysis of spectra based on the properties of the cross correlation between a real spectrum and either a numerical synthesis or laboratory simulation. A new goodness-of-fit criterion called the heteromorphic coefficient H is proposed that has the property of being zero when a fit is achieved and varying smoothly through zero as the iteration proceeds, providing a powerful tool for automatic or near-automatic analysis. It is also shown that H can be rendered substantially noise-immune, permitting the analysis of very weak spectra well below the apparent noise level and, as a byproduct, providing Doppler shift and radial velocity information with excellent precision. The technique is in regular use in the Atmospheric Trace Molecule Spectroscopy (ATMOS) project and operates in an interactive, realtime computing environment with turn-around times of a few seconds or less.
Automated analysis of stellar spectra
NASA Astrophysics Data System (ADS)
Allende Prieto, C.
Classical model-atmosphere analyses of stellar spectra usually begin by measuring equivalent widths, and then proceed into a loop in which 1) model spectra are calculated for a set of abundances and atmospheric parameters, and 2) observed and computed spectra are compared and corrections to the abundances and parameters are inferred. Automated techniques have been developed to automate the measurement of equivalent widths, and some or all parts in the analysis loop. However, in order to tackle the massive datasets provided by the new spectroscopic surveys with dedicated telescopes, it is necessary to make some radical changes. It is argued that future analyses of stellar spectra should abandon the use of equivalent widths, and rely on tables of synthetic spectra that can be either interpolated extremely fast in minimum-distance optimization methods or used for training genetic algorithms. Examples of ongoing projects involving high-dispersion stellar spectra for a small sample and low-dispersion spectra for a sample of tens of thousands of stars are described.
Quantum electromagnetic waves in nonstationary linear media
NASA Astrophysics Data System (ADS)
Pedrosa, I. A.
We present a quantum description of electromagnetic waves propagating through time-dependent homogeneous nondispersive conducting and nonconducting linear media without charge sources. Based on the Coulomb gauge and the quantum invariant method, we find the exact wave functions for this problem. In addition, we construct coherent and squeezed states for the quantized electromagnetic waves and evaluate the quantum fluctuations in coordinate and momentum space as well as the uncertainty product for each mode of the electromagnetic field.
Electromagnetic interactions at RHIC and LHC
M. C. Guclu
At LHC energies the Lorentz factor will be 3400 for the Pb + Pb collisions and the electromagnetic interactions will play important roles. Cross sections for the electromagnetic particle productions are very large and can not be ignored for the lifetimes of the beams and background. In this article, we are going to study some of the electromagnetic processes at RHIC and LHC and show the cross section calculations of the electron-positron pair production with the giant dipole resonance of the ions.
Manager's Role in Electromagnetic Interference (EMI) Control
NASA Technical Reports Server (NTRS)
Sargent, Noel B.; Lewis, Catherine C.
This presentation captures the essence of electromagnetic compatibility (EMC) engineering from a project manager's perspective. It explains the basics of EMC and the benefits to the project of early incorporation of EMC best practices. The EMC requirement products during a project life cycle are identified, along with the requirement verification methods that should be utilized. The goal of the presentation is to raise awareness and simplify the mystique surrounding electromagnetic compatibility for managers that have little or no electromagnetics background
Thin sheet casting with electromagnetic pressurization
Walk, Steven R. (Winterport, ME); Slepian, R. Michael (Pittsburgh, PA); Nathenson, Richard D. (Pittsburgh, PA); Williams, Robert S. (Fairfield, OH)
An apparatus, method and system for the casting of thin strips or strips of metal upon a moving chill block that includes an electromagnet located so that molten metal poured from a reservoir onto the chill block passes into the magnetic field produced by the electromagnet. The electromagnet produces a force on the molten metal on said chill block in the direction toward said chill block in order to enhance thermal contact between the molten metal and the chill block.
Electromagnetic Imaging Methods for Nondestructive Evaluation Applications
Deng, Yiming; Liu, Xin
Electromagnetic nondestructive tests are important and widely used within the field of nondestructive evaluation (NDE). The recent advances in sensing technology, hardware and software development dedicated to imaging and image processing, and material sciences have greatly expanded the application fields, sophisticated the systems design and made the potential of electromagnetic NDE imaging seemingly unlimited. This review provides a comprehensive summary of research works on electromagnetic imaging methods for NDE applications, followed by the summary and discussions on future directions. PMID:22247693
Scalar invariants in gravitational and electromagnetic fields
Zihua Weng
The paper discusses some scalar invariants in the gravitational field and electromagnetic field by means of the characteristics of the quaternions. When we emphasize some definitions of quaternion physical quantities, the speed of light, mass density, energy density, power density, charge density, and spin magnetic moment density etc. will remain the same respectively in the gravitational and electromagnetic fields under the coordinate transformation. The results explain why there are some relationships among different invariants in the gravitational and electromagnetic fields.

subset: commoncrawl