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Security approaches for Radio Frequency Identification systems
In this thesis, I explore the challenges related to the security of the Electronic Product Code (EPC) class of Radio Frequency Identification (RFID) tags and associated data. RFID systems can be used to improve supply chain ...
Foley, Joseph Timothy, 1976-
Radio Frequency Identification : regulating information privacy protection
As applications of Radio Frequency Identification (RFID) become more profuse, the technology itself is stirring up some controversy. Due to its potential for amassing large amounts of information about both people and ...
Laufer, Deanna (Deanna Raquel)
RFIDSim : a discrete event simulator for Radio Frequency Identification systems
This thesis presents RFIDSim, a discrete event process-oriented simulator designed to model Radio Frequency Identification (RFID) communication. The simulator focuses on the discovery and identification process of passive ...
Yu, Kenneth Kwan-Wai, 1979-
Chips, tags and scanners: Ethical challenges for radio frequency identification
Science Conference Proceedings (OSTI)
Radio Frequency Identification (RFID) systems identify and track objects, animals and, in principle, people. The ability to gather information obtained by tracking consumer goods, government documents, monetary transactions and human beings raises a ... Keywords: RFID, business ethics, ethics, privacy, radio frequency identification, surveillance
Dara J. Glasser; Kenneth W. Goodman; Norman G. Einspruch
Radio-Frequency Identification (RFID) applications: A brief introduction
Science Conference Proceedings (OSTI)
This short paper introduces the key concepts behind RFID technology and presents a brief historical perspective. Examples of RFID applications are also given to highlight the developing popularity of the technology in many sectors. This paper will provide ... Keywords: Antenna, Radio-Frequency Identification, Reader, Tagging, Tracking, Transponder
Konstantinos Domdouzis; Bimal Kumar; Chimay Anumba
Multi-dimensional ultra-high frequency passive radio frequency identification tag antenna designs
In this thesis, we present the design, simulation, and empirical evaluation of two novel multi-dimensional ultra-high frequency (UHF) passive radio frequency identification (RFID) tag antennas, the Albano-Dipole antenna ...
Delichatsios, Stefanie Alkistis
Enhancement of electromagnetic propagation through complex media for Radio Frequency Identification
In this thesis, I present and examine the fundamental limitations involved in Radio Frequency Identification (RFID) as well as provide a means to improve reader-tag communication in ultra high frequency RFID systems. The ...
Marti, Uttara P
A Radio Frequency Identification (RFID) evaluation strategy for customer fulfillment centers
Radio Frequency Identification (RFID) is a wireless technology that can be used to track inventory labeled with microchip-embedded identifiers communicating passively with scanners without operator involvement. This ...
Shen, Howard H. (Howard Hao)
A new method for indoor location base on radio frequency identification
Science Conference Proceedings (OSTI)
In recent years, there has dramatic proliferation of research concerned with Radio Frequency Identification (RFID). The RFID technologies are getting considerable attentions not only academic research but also the applications of enterprise. One of most ... Keywords: LANDMRC, RFID, RSS, indoor position location, location identification, powel level
Rung-Ching Chen; Sheng-Ling Huang
Science Conference Proceedings (OSTI)
The research literature on Radio Frequency Identification (RFID) has grown exponentially in recent years. In a domain where new concepts and techniques are constantly being introduced, it is of interest to analyze recent trends in this literature. Although ... Keywords: Citation analysis, Radio Frequency Identification (RFID), Science Citation Index (SCI), Social Science Citation Index (SSCI)
Wei-Pang Liao; Tom M. Y. Lin; Shu-Hsien Liao
Investigation of the State and Uses of Ultra-Wide-Band Radio-Frequency Identification Technology
Radio-frequency identification (RFID) technology has revolutionized the concept of asset tracking. By affixing an RFID tag to a valued asset, one can track the item throughout any facility where RIFD readers are in place, thereby alerting inspectors to theft, misuse, and misplacement of the tracked item. While not yet implemented for tracking very high value assets, RFID technology is already widely used in many industries as the standard for asset tracking. A subset of RFID technology exists called Ultra-Wide-Band (UWB) RFID. While traditional (sometimes called narrow-band) RFID technology transmits a continuous sine-wave signal of a narrow frequency range, UWB technology works by transmitting signals as short pulses of a broad frequency range. This improves performance in several areas, namely, range, precision, and accuracy of motion detection. Because of the nature of the technology, it also performs well in close proximity to metal, which sets it apart from traditional RFID. The purpose of this paper is to investigate the current state of UWB RFID technology and research the areas where it already is being used. This is accomplished through study of publicly known uses of the technology as well as personal exploration of RFID hardware and software. This paper presents the findings in a general manner to facilitate their usefulness for diverse applications.
Hickerson, Jonathan W [ORNL; Younkin, James R [ORNL
Recent advances in radio frequency identification devices (RFIDs) have engendered a growing interest among international safeguards experts. Potentially, RFIDs could reduce inspection work, viz. the number of inspections, number of samples, and duration of the visits, and thus improve the efficiency and effectiveness of international safeguards. This study systematically examined the applications of RFIDs for IAEA safeguards at large gas-centrifuge enrichment plants (GCEPs). These analyses are expected to help identify the requirements and desirable properties for RFIDs, to provide insights into which vulnerabilities matter most, and help formulate the required assurance tests. This work, specifically assesses the application of RFIDs for the ''Option 4'' safeguards approach, proposed by Bruce Moran, U. S. Nuclear Regulatory Commission (NRC), for large gas-centrifuge uranium-enrichment plants. The features of ''Option 4'' safeguards include placing RFIDs on all feed, product and tails (F/P/T) cylinders, along with WID readers in all FP/T stations and accountability scales. Other features of Moran's ''Option 4'' are Mailbox declarations, monitoring of load-cell-based weighing systems at the F/P/T stations and accountability scales, and continuous enrichment monitors. Relevant diversion paths were explored to evaluate how RFIDs improve the efficiency and effectiveness of safeguards. Additionally, the analysis addresses the use of RFIDs in conjunction with video monitoring and neutron detectors in a perimeter-monitoring approach to show that RFIDs can help to detect unidentified cylinders.
Science Conference Proceedings (OSTI)
Global expansion of nuclear power has made the need for improved safeguards measures at Gas Centrifuge Enrichment Plants (GCEPs) imperative. One technology under consideration for safeguards applications is Radio Frequency Identification Devices (RFIDs). RFIDs have the potential to increase IAEA inspector"s efficiency and effectiveness either by reducing the number of inspection visits necessary or by reducing inspection effort at those visits. This study assesses the use of RFIDs as an integral component of the "Option 4" safeguards approach developed by Bruce Moran, U.S. Nuclear Regulatory Commission (NRC), for a model GCEP [1]. A previous analysis of RFIDs was conducted by Jae Jo, Brookhaven National Laboratory (BNL), which evaluated the effectiveness of an RFID tag applied by the facility operator [2]. This paper presents a similar evaluation carried out in the framework of Jo�s paper, but it is predicated on the assumption that the RFID tag is applied by the manufacturer at the birth of the cylinder, rather than by the operator. Relevant diversion scenarios are examined to determine if RFIDs increase the effectiveness and/ or efficiency of safeguards in these scenarios. Conclusions on the benefits offered to inspectors by using in-born RFID tagging are presented.
Ward,R.; Rosenthal,M.
Stabilized radio frequency quadrupole
Disclosed is a long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator. 5 figs.
Lancaster, H.D.; Fugitt, J.A.; Howard, D.R.
Science Conference Proceedings (OSTI)
The US Department of Energy (DOE) [Environmental Management (EM), Office of Packaging and Transportation (EM-45)] Packaging Certification Program (PCP) has developed a radiofrequency identification (RFID) tracking and monitoring system for the management of nuclear materials packages during storage and transportation. The system, developed by the PCP team at Argonne National Laboratory, involves hardware modification, application software development, secured database and web server development, and irradiation experiments. In April 2008, Argonne tested key features of the RFID tracking and monitoring system in a weeklong, 1700 mile (2736 km) demonstration employing 14 empty type B fissile material drums of three designs (models 9975, 9977 and ES-3100) that have been certified for shipment by the DOE and the US Nuclear Regulatory Commission. The demonstration successfully integrated global positioning system (GPS) technology for vehicle tracking, satellite/cellular (general packet radio service, or GPRS) technologies for wireless communication, and active RFID tags with multiple sensors (seal integrity, shock, temperature, humidity and battery status) on drums. In addition, the demonstration integrated geographic information system (GIS) technology with automatic alarm notifications of incidents and generated buffer zone reports for emergency response and management of staged incidents. The demonstration was sponsored by EM and the US National Nuclear Security Administration, with the participation of Argonne, Savannah River and Oak Ridge National Laboratories. Over 50 authorised stakeholders across the country observed the demonstration via secured Internet access. The DOE PCP and national laboratories are working on several RFID system implementation projects at selected DOE sites, as well as continuing device and systems development and widening applications beyond DOE sites and possibly beyond nuclear materials to include other radioactive materials.
Tsai, H. C.; Chen, K.; Liu, Y. Y.; Shuler, J. (Decision and Information Sciences); (USDOE)
Radio Frequency Engineering, MDE, Accelerator Operations and...
NLE Websites -- All DOE Office Websites (Extended Search)
Home Teams Low-Level Radio Frequency Magnet Power Supplies, Pulsed Power Radio Frequency, High Voltage Technologies Radio Frequency Operations CONTACTS Group Leader Dan Rees Deputy...
Radio frequency coaxial feedthrough
An improved radio frequency coaxial transmission line vacuum feed-through provided based on the use of a half-wavelength annular dielectric pressure barrier disk, or multiple disks comprising an effective half wavelength structure to eliminate reflections from the barrier surfaces. Gas-tight seals are formed about the outer and inner diameter surfaces of the barrier disk using a sealing technique which generates radial forces sufficient to form seals by forcing the conductor walls against the surfaces of the barrier disks in a manner which does not deform the radii of the inner and outer conductors, thereby preventing enhancement of the electric field at the barrier faces which limits voltage and power handling capabilities of a feedthrough.
Owens, Thomas L. (Kingston, TN)
Stabilized radio-frequency quadrupole
A long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator.
Lancaster, H.D.; Fugitt, J.A.; Howard, D.R.
The Packaging Certification Program (PCP) of the U.S. Department of Energy (DOE) Environmental Management (EM), Office of Packaging and Transportation (EM-14), has developed a radio frequency identification (RFID) tracking and monitoring system for the management of nuclear materials during storage and transportation. The system, developed by the PCP team at Argonne National Laboratory, consists of hardware (Mk-series sensor tags, fixed and handheld readers, form factor for multiple drum types, seal integrity sensors, and enhanced battery management), software (application programming interface, ARG-US software for local and remote/web applications, secure server and database management), and cellular/satellite communication interfaces for vehicle tracking and item monitoring during transport. The ability of the above system to provide accurate, real-time tracking and monitoring of the status of multiple, certified containers of nuclear materials has been successfully demonstrated in a week-long, 1,700-mile DEMO performed in April 2008. While the feedback from the approximately fifty (50) stakeholders who participated in and/or observed the DEMO progression were very positive and encouraging, two major areas of further improvements - system integration and web application enhancement - were identified in the post-DEMO evaluation. The principal purpose of the MiniDemo described in this report was to verify these two specific improvements. The MiniDemo was conducted on August 28, 2009. In terms of system integration, a hybrid communication interface - combining the RFID item-monitoring features and a commercial vehicle tracking system by Qualcomm - was developed and implemented. In the MiniDemo, the new integrated system worked well in reporting tag status and vehicle location accurately and promptly. There was no incompatibility of components. The robust commercial communication gear, as expected, helped improve system reliability. The MiniDemo confirmed that system integration is technically feasible and reliable with the existing RFID and Qualcomm satellite equipment. In terms of web application, improvements in mapping, tracking, data presentation, and post-incident spatial query reporting were implemented in ARG-US, the application software that manages the dataflow among the RFID tags, readers, and servers. These features were tested in the MiniDemo and found to be satisfactory. The resulting web application is both informative and user-friendly. A joint developmental project is being planned between the PCP and the DOE TRANSCOM that uses the Qualcomm gear in vehicles for tracking and communication of radioactive material shipments across the country. Adding an RFID interface to TRANSCOM is a significant enhancement to the DOE infrastructure for tracking and monitoring shipments of radioactive materials.
Tsai, H.; Chen, K.; Jusko, M.; Craig, B.; Liu, Y.; Decision and Information Sciences
Radio frequency coaxial feedthrough device
A radio frequency coaxial vacuum feedthrough is provided which utilizes a cylindrical ceramic vacuum break formed of an alumina ceramic. The cylinder is coaxially disposed and brazed between tapered coaxial conductors to form a vacuum sealed connection between a pressurized upstream coaxial transmission line and a utilization device located within a vacuum container. The feedthrough provides 50 ohm matched impedance RF feedthrough up to about 500 MHz at power levels in the multimegawatt range.
Owens, Thomas L. (Kingston, TN); Baity, Frederick W. (Oak Ridge, TN); Hoffman, Daniel J. (Oak Ridge, TN); Whealton, John H. (Oak Ridge, TN)
Radio frequency fingerprinting commercial communication devices to enhance electronic security
Science Conference Proceedings (OSTI)
There is a current shift toward protecting against unauthorised network access at the open systems interconnection physical layer by exploiting radio frequency characteristics that are difficult to mimic. This work addresses the use of RF 'fingerprints' ... Keywords: Fisher linear discriminant, OSI, PHY layer authentication, RF fingerprinting, RF forensics, SEI, access authorisation, anti-spoofing, burst detection, commercial communication devices, electronic security, feature generation, multiple discriminant analysis, network access, physical layer authentication, radio frequency fingerprinting, signal features, specific emitter identification, transient detection
William C. Suski II; Michael A. Temple; Michael J. Mendenhall; Robert F. Mills
A radio frequency coaxial feedthrough
An improved radio frequency coaxial transmission line vacuum feedthrough is provided based on the use of a half-wavelength annular dielectric pressure barrier disk, or multiple disks comprising an effective half wavelength structure to eliminate reflection from the barrier surfaces. Gas-tight seals are formed about the outer and inner diameter surfaces of the barrier disk using a sealing technique which generates radial forces sufficient to form seals by forcing the conductor walls against the surfaces of the barrier disks in a manner which does not deform the radii of the inner and outer conductors, thereby preventing enhancement of the electric field at the barrier faces which limits the voltage and power handling capabilities of a feedthrough.
Owens, T.L.
Radio frequency sustained ion energy
Electromagnetic (E.M.) energy injection method and apparatus for producing and sustaining suprathermal ordered ions in a neutral, two-ion-species, toroidal, bulk equilibrium plasma. More particularly, the ions are produced and sustained in an ordered suprathermal state of existence above the average energy and velocity of the bulk equilibrium plasma by resonant rf energy injection in resonance with the natural frequency of one of the ion species. In one embodiment, the electromagnetic energy is injected to clamp the energy and velocity of one of the ion species so that the ion energy is increased, sustained, prolonged and continued in a suprathermal ordered state of existence containing appreciable stored energy that counteracts the slowing down effects of the bulk equilibrium plasma drag. Thus, selective deuteron absorption may be used for ion-tail creation by radio-frequency excitation alone. Also, the rf can be used to increase the fusion output of a two-component neutral injected plasma by selective heating of the injected deuterons.
Jassby, Daniel L. (Princeton, NJ); Hooke, William M. (Princeton, NJ)
Integrally formed radio frequency quadrupole
An improved radio frequency quadrupole (10) is provided having an elongate housing (11) with an elongate central axis (12) and top, bottom and two side walls (13a-d) symmetrically disposed about the axis, and vanes (14a-d) formed integrally with the walls (13a-d), the vanes (14a-d) each having a cross-section at right angles to the central axis (12) which tapers inwardly toward the axis to form electrode tips (15a-d) spaced from each other by predetermined distances. Each of the four walls (13a-d), and the vanes (14a-d) integral therewith, is a separate structural element having a central lengthwise plane (16) passing through the tip of the vane, the walls (13a-d) having flat mounting surfaces (17, 18) at right angles to and parallel to the control plane (16), respectively, which are butted together to position the walls and vane tips relative to each other.
Abbott, Steven R. (Concord, CA)
High power radio frequency attenuation device
A resistor device for attenuating radio frequency power includes a radio frequency conductor connected to a series of fins formed of high relative magnetic permeability material. The fins are dimensional to accommodate the skin depth of the current conduction therethrough, as well as an inner heat conducting portion where current does not travel. Thermal connections for air or water cooling are provided for the inner heat conducting portions of each fin. Also disclosed is a resistor device to selectively alternate unwanted radio frequency energy in a resonant cavity.
Kerns, Quentin A. (Bloomingdale, IL); Miller, Harold W. (Winfield, IL)
Overview of Personal Radio Frequency Communication Technologies
Science Conference Proceedings (OSTI)
The growth of wireless electronic communication devices and their applications is creating an increasingly complex radio frequency (RF) environment in the workplace and home. Personal communication applications discussed in this report include cordless telephones, analog cellular telephones, digital cellular telephones, and a dozen more. Depending on the specific wireless device, different frequency ranges, modulation types, multiple access types, and power levels can be encountered. The significant grow...
Development of Radio Frequency Exposure Standards
Science Conference Proceedings (OSTI)
While unconfirmed claims of adverse human health effects from electromagnetic radiation date to the 1930s, development of modern safety standards did not begin until the 1952 Hirsch study of eye damage at a microwave power density of 100 mW/cm2. Early work on standards focused on microwave frequencies due to rapid development of radar and microwave communications links. In the years since 1952, radio frequency (RF) exposure standards have kept pace with those technological advancements. While refinements...
Home monitoring using wearable radio frequency transmitters
Science Conference Proceedings (OSTI)
Background: Location tracking of a wearable radio frequency (RF) transmitter in a wireless network is a potentially useful tool for the home monitoring of patients in clinical applications. However, the problem of converting RF signals into accurate ... Keywords: Gaussian mixture models, Home monitoring, Motion tracking, Wireless network
Anthony Almudevar; Adrian Leibovici; Aleksey Tentler
A Power-efficient Radio Frequency Energy-harvesting Circuit .
??This work aims to demonstrate the design and simulation of a Radio Frequency (RF) energy-harvesting circuit, from receiving antenna to the point of charge collection.� (more)
Khoury, Philip
Trirotron: triode rotating beam radio frequency amplifier
High efficiency amplification of radio frequencies to very high power levels including: establishing a cylindrical cloud of electrons; establishing an electrical field surrounding and coaxial with the electron cloud to bias the electrons to remain in the cloud; establishing a rotating electrical field that surrounds and is coaxial with the steady field, the circular path of the rotating field being one wavelength long, whereby the peak of one phase of the rotating field is used to accelerate electrons in a beam through the bias field in synchronism with the peak of the rotating field so that there is a beam of electrons continuously extracted from the cloud and rotating with the peak; establishing a steady electrical field that surrounds and is coaxial with the rotating field for high-energy radial acceleration of the rotating beam of electrons; and resonating the rotating beam of electrons within a space surrounding the second field, the space being selected to have a phase velocity equal to that of the rotating field to thereby produce a high-power output at the frequency of the rotating field.
Lebacqz, Jean V. (Stanford, CA)
Macroscopic Diversity in Frequency Reuse Radio Systems
Science Conference Proceedings (OSTI)
Macroscopic diversity is a technique that can facilitate high quality and ubiquitous communications between low-power portable radiotelephones and data terminals, and radio base stations (ports) that are connected to the local network. It uses radio ...
R. Bernhardt
Method and apparatus for radio frequency ceramic sintering
Radio frequency energy is used to sinter ceramic materials. A coaxial waveguide resonator produces a TEM mode wave which generates a high field capacitive region in which a sample of the ceramic material is located. Frequency of the power source is kept in the range of radio frequency, and preferably between 60-80 MHz. An alternative embodiment provides a tunable radio frequency circuit which includes a series input capacitor and a parallel capacitor, with the sintered ceramic connected by an inductive lead. This arrangement permits matching of impedance over a wide range of dielectric constants, ceramic volumes, and loss tangents. 6 figures.
Hoffman, D.J.; Kimrey, H.D. Jr.
Method and apparatus for radio frequency ceramic sintering
Radio frequency energy is used to sinter ceramic materials. A coaxial waveguide resonator produces a TEM mode wave which generates a high field capacitive region in which a sample of the ceramic material is located. Frequency of the power source is kept in the range of radio frequency, and preferably between 60-80 MHz. An alternative embodiment provides a tunable radio frequency circuit which includes a series input capacitor and a parallel capacitor, with the sintered ceramic connected by an inductive lead. This arrangement permits matching of impedance over a wide range of dielectric constants, ceramic volumes, and loss tangents.
Hoffman, Daniel J. (Oak Ridge, TN); Kimrey, Jr., Harold D. (Knoxville, TN)
High-power radio-frequency attenuation device
A resistor device for attenuating radio frequency power includes a radio frequency conductor connected to a series of fins formed of high relative magnetic permeability material. The fins are dimensional to accommodate the skin depth of the current conduction therethrough, as well as an inner heat conducting portion where current does not travel. Thermal connections for air or water cooling are provided for the inner heat conducting portions of each fin. Also disclosed is a resistor device to selectively alternate unwanted radio frequency energy in a resonant cavity.
Kerns, Q.A.; Miller, H.W.
Radio-frequency spectroscopy of ultracold atomic Fermi gases
This thesis presents experiments investigating the phase diagram of ultracold atomic Fermi gases using radio-frequency spectroscopy. The tunability of many experimental parameters including the temperature, the interparticle ...
Schirotzek, Andre
UTag: Long-range Ultra-wideband Passive Radio Frequency Tags
Long-range, ultra-wideband (UWB), passive radio frequency (RF) tags are key components in Radio Frequency IDentification (RFID) system that will revolutionize inventory control and tracking applications. Unlike conventional, battery-operated (active) RFID tags, LLNL's small UWB tags, called 'UTag', operate at long range (up to 20 meters) in harsh, cluttered environments. Because they are battery-less (that is, passive), they have practically infinite lifetimes without human intervention, and they are lower in cost to manufacture and maintain than active RFID tags. These robust, energy-efficient passive tags are remotely powered by UWB radio signals, which are much more difficult to detect, intercept, and jam than conventional narrowband frequencies. The features of long range, battery-less, and low cost give UTag significant advantage over other existing RFID tags.
Dowla, F
UTag: Long-range Ultra-wideband Passive Radio Frequency Tags
Long-range, ultra-wideband (UWB), passive radio frequency (RF) tags are key components in Radio Frequency IDentification (RFID) system that will revolutionize inventory control and tracking applications. Unlike conventional, battery-operated (active) RFID tags, LLNL's small UWB tags, called 'UTag', operate at long range (up to 20 meters) in harsh, cluttered environments. Because they are battery-less (that is, passive), they have practically infinite lifetimes without human intervention, and they are lower in cost to manufacture and maintain than active RFID tags. These robust, energy-efficient passive tags are remotely powered by UWB radio signals, which are much more difficult to detect, intercept, and jam than conventional narrowband frequencies. The features of long range, battery-less, and low cost give UTag significant advantage over other existing RFID tags.
Dowla, F
Method and Apparatus for Pasteurizing Shell Eggs Using Radio Frequency
NLE Websites -- All DOE Office Websites (Extended Search)
Method and Apparatus for Pasteurizing Shell Eggs Using Radio Frequency Method and Apparatus for Pasteurizing Shell Eggs Using Radio Frequency Heating" Inventors..--.. Christopher D. Brunkhorst, David J. Geveke, Andrew B. W. Bigley. This disclosure is directed to a system for pasteurizing shell eggs. The system includes an egg rotating assembly structured to rotate the egg, and electrodes that are in contact with the egg. The system is structured so that, as the rotating assembly rotates the egg, radio frequency energy is directed to the egg to pasteurize it. Nearly 200 million "shell eggs" are consumed in the United States (US) each day. "Shell eggs" are non-powdered conventional eggs that are naturally produced by hens. Shell eggs are among the most nutritious foods on earth and can be part of a healthy diet. However, some unbroken, clean, fresh
Radio frequency dc-dc power conversion
THIS THESIS addresses the development of system architectures and circuit topologies for dc-dc power conversion at very high frequencies. The systems architectures that are developed are structured to overcome limitations ...
Rivas, Juan, 1976-
Plasma ignition schemes for the SNS radio-frequency driven H- source
on the Spallation Neutron Source (SNS) Project,� EPAC �98,ignition schemes for the SNS radio-frequency driven H -the Spallation Neutron Source (SNS) is a cesiated, radio-
Towards Optimization of Probe Placement for Radio-Frequency Ablation
's electric potential and of the steady state of the heat distribution during RF ablation. The optimization of the optimization to artificial data and a comparison to a real RF ablation are presented. 1 Introduction on Cartesian or tetrahedral grids. In this work we consider the radio-frequency (RF) ablation of liver tumors
Preusser, Tobias
Radio frequency communication system utilizing radiating transmission lines
A radio communication system for use in tunnels, mines, buildings or other shielded locations in which a pair of radiating transmission lines (30), (31) extend through such location in spaced coextensive relation to each other. Each transmission line (30), (31) has at least one unidirectional amplifier (32), (33) interposed therein with the sense of the unidirectional amplifier (32) of one transmission line (30) being opposite to the sense of the unidirectional amplifier (33) of the other transmission line (31). Each of the amplifiers (32), (33) has a gain which is less than the coupling loss between the transmission lines (30), (31). Two or more mobile transceivers (35) in the location served by the system are coupled to the transmission lines (30), (31) by electromagnetic wave propagation in space in order to communicate directly with each other at a given radio frequency within the frequency range of the system.
Struven, Warren C. (San Carlos, CA)
Electronic Radio-Frequency (Electrodeless) Induction Lamps: A Fluorescent Technology
Science Conference Proceedings (OSTI)
This EPRI Technical Update addresses an expanding energy efficient light source electronic radio-frequency (electrodeless) induction lamps. Business and technical market factors (Chapter 2) use the past and future growth of the CFL market to illustrate the potential for the induction lighting market while emphasizing future technical improvements. Discussion of the importance of utility involvement in helping their customers consider induction lamps for high-efficiency fluorescent applications with long-...
Ross Ice Shelf in situ radio-frequency ice attenuation
We have measured the in situ average electric field attenuation length for radio-frequency signals broadcast vertically through the Ross Ice Shelf. We chose a location, Moore Embayment, south of Minna Bluff, known for its high reflectivity at the ice-sea interface. We confirmed specular reflection and used the return pulses to measure the average attenuation length from 75-1250 MHz over the round-trip distance of 1155 m. We find the average electric field attenuation length to vary from 500 m at 75 MHz to 300 m at 1250 MHz, with an experimental uncertainty of 55 to 15 m. We discuss the implications for neutrino telescopes that use the radio technique and include the Ross Ice Shelf as part of their sensitive volume.
Taylor Barrella; Steven Barwick; David Saltzberg
Radio-Frequency (RF) Devices for Safeguards: Where We Are and Where We Need to Go
Science Conference Proceedings (OSTI)
Radio-Frequency (RF) devices have revolutionized many aspects of modern industrial processes. RF technology can enable wireless communication for tag identification, sensor communication, and asset tracking. Radio-frequency identification (RFID) is a technology that utilizes wireless communication to interrogate and identify an electronic tag attached to an item in order to identify the item. The technology can come in many forms: passive or active tags, low to ultra-wideband frequencies, small paper-thin tags to brick-sized units, and simple tags or highly integrated sensor packages. RF technology, and specifically RFID, has been applied widely in commercial markets for inventory, supply chain management, and asset tracking. Several recent studies have demonstrated the safeguards benefits of utilizing RFID versus conventional inventory tagging methods for tracking nuclear material. These studies have indicated that the RF requirements for safeguards functions are more stringent than the RF requirements for other inventory tracking and accounting applications. Additionally, other requirements must be addressed, including environmental and operating conditions, authentication, and tag location and attachment. Facility restrictions on radio spectrum, method of tag attachment, and sensitivity of the data collected impact the tag selection and system design. More important, the intended use of the system must be considered. The requirements for using RF to simply replace or supplement container identifiers such as bar codes that facilitate the inventory function will differ greatly from the requirements for deploying RF for unattended monitoring applications. Several studies have investigated these considerations to advance commercial RF devices for safeguards use, and a number of system concepts have been developed. This paper will provide an overview of past studies and current technologies, and will investigate the requirements, existing gaps, and several potential next steps for advancing RF techniques for safeguards use.
Rowe, Nathan C [ORNL; Younkin, James R [ORNL; Pickett, Chris A [ORNL; Whitaker, J Michael [ORNL
Design and characterization of a radio-frequency dc/dc power converter
The use of radio-frequency (RF) amplifier topologies in dc/dc power converters allows the operating frequency to be increased by more than two orders of magnitude over the frequency of conventional converters. This enables ...
Jackson, David A. (David Alexander)
Radio-Frequency Interference (RFI) From Extra-High- Voltage (EHV) Transmission Lines
The subject of radio-frequency interference (RFI) generated by high-voltage transmission lines has long been of both academic and commercial interest because of concerns about
Patrick C. Crane
RFQ (radio-frequency quadrupole) acceleration section and its optimization
The acceleration section is a crucial component of any radio- frequency quadrupole (RFQ). It is common a practice to design this section with a constant modulation factor equal to its value at the end of the gentle buncher. A new method of design is proposed in this paper. The algorithm is based on the fact that the transverse space-charge current limit (TCL) is approximately proportional to the instantaneous velocity of the accelerated particle and the longitudinal space-charge current limit (LCL) is nearly independent of the velocity in the acceleration section. The modulation factor is increased such that the TCL is slightly larger than the double of the design current. Simulation using this method shows that transmission efficiency and emittances are the same as the conventional design. The advantage gained is a 50-75% increase in accelerating rate. The optimization of the length of this section is also discussed. 3 refs., 4 figs., 1 tab.
Raparia, D.
Superconducting radio-frequency modules test faciilty operating experience
Science Conference Proceedings (OSTI)
Fermilab is heavily engaged and making strong technical contributions to the superconducting radio-frequency research and development program (SRF R&D). Four major SRF test areas are being constructed to enable vertical and horizontal cavity testing, as well as cryomodule testing. The existing Fermilab cryogenic infrastructure has been modified to service Fermilab SRF R&D needs. The first stage of the project has been successfully completed, which allows for distribution of cryogens for a single cavity cryomodule using the existing Cryogenic Test Facility (CTF) that houses three Tevatron satellite refrigerators. The cooling capacity available for cryomodule testing at MDB results from the liquefaction capacity of the CTF cryogenic system. The cryogenic system for a single 9-cell cryomodule is currently operational. The paper describes the status, challenges and operational experience of the initial phase of the project.
Soyars, W.; Bossert, R.; Darve, C.; Degraff, B.; Klebaner, A.; Martinez, A.; Pei, L.; Theilacker, J.; /Fermilab
Free-Free Emission at Low Radio Frequencies
We discuss free-free radio emission from ionized gas in the intergalactic medium. Because the emissivity is proportional to the square of the electron density, the mean background is strongly sensitive to the spatial clumping of free electrons. Using several existing models for the clumping of ionized gas, we find that the expected free-free distortion to the cosmic microwave background (CMB) blackbody spectrum is at a level detectable with upcoming experiments such as the Absolute Radiometer for Cosmology, Astrophysics, and Diffuse Emission (ARCADE). However, the dominant contribution to the distortion comes from clumpy gas at z free-free background and the extent to which these anisotropies confuse the search for fluctuations in 21 cm line emission from neutral hydrogen during and prior to reionization. This background is smooth in frequency space and hence can be removed through frequency differencing, but only so long as the 21 cm signal and the free-free emission are uncorrelated. We show that, because the free-free background is generated primarily at low redshifts, the cross-correlation between the two fields is smaller than a few percent. Thus, multifrequency cleaning should be an effective way to eliminate the free-free confusion.
Asantha Cooray; Steven Furlanetto
Energy Saving Glass Lamination via Selective Radio Frequency Heating
Ceralink Inc. developed FastFuse�, a rapid, new, energy saving process for lamination of glass and composites using radio frequency (RF) heating technology. The Inventions and Innovations program supported the technical and commercial research and development needed to elevate the innovation from bench scale to a self-supporting technology with significant potential for growth. The attached report provides an overview of the technical and commerical progress achieved for FastFuse� during the course of the project. FastFuse� has the potential to revolutionize the laminate manufacturing industries by replacing energy intensive, multi-step processes with an energy efficient, single-step process that allows higher throughput. FastFuse� transmits RF energy directly into the interlayer to generate heat, eliminating the need to directly heat glass layers and the surrounding enclosures, such as autoclaves or vacuum systems. FastFuse� offers lower start-up and energy costs (up to 90% or more reduction in energy costs), and faster cycles times (less than 5 minutes). FastFuse� is compatible with EVA, TPU, and PVB interlayers, and has been demonstrated for glass, plastics, and multi-material structures such as photovoltaics and transparent armor.
Shawn M. Allan; Patricia M. Strickland; Holly S. Shulman
Economics of shale oil production by radio frequency heating
A conceptual facility for the production of shale oil by radio frequency(rf) heating has been designed to evaluate the economic feasibility of this technique. In the proposed procedure, the shale is processed in situ without being rubbed or explosively fractured. Metal electrodes inserted in a set of vertical drill holes are energized by a group of rf oscillators. The holes bound a block of shale that is to be retorted. The electric field is developed in such a way that heating within the block is almost uniform, and heating outside the block is very low. Retorting of the shale results in a pressure buildup of the hydrocarbon fluids. The oil and gas move horizontally (parallel to bedding planes), then down the electrode holes to a collection manifold. The facility schedule is planned so that off-peak electric power from existing generating stations can be used to operate the oscillators. Thus, the cost of power and the capital requirements for the facility are held to a minimum. Oil production costs and capital requirements indicate that the proposed procedure is economically attractive. The two principal costs are purchase of electric power and mining operations. The largest capital requirement is oscillators and associated electrical equipment.
Mallon, R.G.
Method of making radio frequency ion source antenna
In the method, the radio frequency (RF) antenna is made by providing a clean coil made of copper tubing or other metal conductor, which is coated with a tacky organic binder, and then with a powdered glass frit, as by sprinkling the frit uniformly over the binder. The coil is then heated internally in an inert gas atmosphere, preferably by passing an electrical heating current along the coil. Initially, the coil is internally heated to about 200.degree. C. to boil off the water from the binder, and then to about 750.degree. C.-850.degree. C. to melt the glass frit, while also burning off the organic binder. The melted frit forms a molten glass coating on the metal coil, which is then cooled to solidify the glass, so that the metal coil is covered with a thin continuous homogeneous impervious glass coating of substantially uniform thickness. The glass coating affords complete electrical insulation and complete dielectric protection for the metal coil of the RF antenna, to withstand voltage breakdown and to prevent sputtering, while also doubling the plasma generating efficiency of the RF antenna, when energized with RF power in the vacuum chamber of an ion source for a particle accelerator or the like. The glass frit preferably contains apprxoimately 45% lead oxide.
Ehlers, Kenneth W. (Alamo, CA); Leung, Ka-Ngo (Hercules, CA)
Proposal for the Purchase, Without a Call for Tenders, of a Fourth Radio-Frequency Transmission Line for the SPS
H- radio frequency source development at the Spallation Neutron Source
Science Conference Proceedings (OSTI)
The Spallation Neutron Source (SNS) now routinely operates nearly 1 MW of beam power on target with a highly persistent {approx}38 mA peak current in the linac and an availability of {approx}90%. H{sup -} beam pulses ({approx}1 ms, 60 Hz) are produced by a Cs-enhanced, multicusp ion source closely coupled with an electrostatic low energy beam transport (LEBT), which focuses the 65 kV beam into a radio frequency quadrupole accelerator. The source plasma is generated by RF excitation (2 MHz, {approx}60 kW) of a copper antenna that has been encased with a thickness of {approx}0.7 mm of porcelain enamel and immersed into the plasma chamber. The ion source and LEBT normally have a combined availability of {approx}99%. Recent increases in duty-factor and RF power have made antenna failures a leading cause of downtime. This report first identifies the physical mechanism of antenna failure from a statistical inspection of {approx}75 antennas which ran at the SNS, scanning electron microscopy studies of antenna surface, and cross sectional cuts and analysis of calorimetric heating measurements. Failure mitigation efforts are then described which include modifying the antenna geometry and our acceptance/installation criteria. Progress and status of the development of the SNS external antenna source, a long-term solution to the internal antenna problem, are then discussed. Currently, this source is capable of delivering comparable beam currents to the baseline source to the SNS and, an earlier version, has briefly demonstrated unanalyzed currents up to {approx}100 mA (1 ms, 60 Hz) on the test stand. In particular, this paper discusses plasma ignition (dc and RF plasma guns), antenna reliability, magnet overheating, and insufficient beam persistence.
Welton, Robert F [ORNL; Pennisi, Terry R [ORNL; Roseberry, Ron T [ORNL; Stockli, Martin P [ORNL
Energy Saving Glass Lamination via Selective Radio-Frequency Heating
This Inventions and Innovations program supported the technical and commercial research and development needed to elevate Ceralink's energy saving process for flat glass lamination from bench scale to a self-supporting technology with significant potential for growth. Radio-frequency heating was any un-explored option for laminating glass prior to this program. With significant commercial success through time and energy savings in the wood, paper, and plastics industries, RF heating was found to have significant promise for the energy intensive glass lamination industry. A major technical goal of the program was to demonstrate RF lamination across a wide range of laminate sizes and materials. This was successfully accomplished, dispelling many skeptics' concerns about the abilities of the technology. Ceralink laminated panels up to 2 ft x 3 ft, with four sets processed simultaneously, in a 3 minute cycle. All major categories of interlayer materials were found to work with RF lamination. In addition to laminating glass, other materials including photovoltaic silicon solar cells, light emitting diodes, metallized glass, plastics (acrylic and polycarbonate), and ceramics (alumina) were found compatible with the RF process. This opens up a wide range of commercial opportunities beyond the initially targeted automotive industry. The dramatic energy savings reported for RF lamination at the bench scale were found to be maintained through the scale up of the process. Even at 2 ft x 3 ft panel sizes, energy savings are estimated to be at least 90% compared to autoclaving or vacuum lamination. With targeted promotion through conference presentations, press releases and internet presence, RF lamination has gained significant attention, drawing large audiences at American Ceramic Society meetings. The commercialization success of the project includes the establishment of a revenue-generating business model for providing process development and demonstrations for potential RF lamination users. A path to industrial energy benefits and revenue through industrial equipment sales was established in a partnership with Thermex Thermatron, a manufacturer of RF equipment.
Shulman, Holly S.; Allan, Shawn M.
Adaptive-rate techniques for frequency-hop multiple-access packet-radio networks
The effects of adaptive-rate transmissions and routing on the total throughput of a slow-frequency-hop packet-radio network are considered. Adaptive rates are achieved through the use of error-control coding with perfect ...
Block, Frederick J., IV
Radio Frequency Station - Beam Dynamics Interaction in Circular Accelerators
Science Conference Proceedings (OSTI)
The longitudinal beam dynamics in circular accelerators is mainly defined by the interaction of the beam current with the accelerating Radio Frequency (RF) stations. For stable operation, Low Level RF (LLRF) feedback systems are employed to reduce coherent instabilities and regulate the accelerating voltage. The LLRF system design has implications for the dynamics and stability of the closed-loop RF systems as well as for the particle beam, and is very sensitive to the operating range of accelerator currents and energies. Stability of the RF loop and the beam are necessary conditions for reliable machine operation. This dissertation describes theoretical formalisms and models that determine the longitudinal beam dynamics based on the LLRF implementation, time domain simulations that capture the dynamic behavior of the RF station-beam interaction, and measurements from the Positron-Electron Project (PEP-II) and the Large Hadron Collider (LHC) that validate the models and simulations. These models and simulations are structured to capture the technical characteristics of the system (noise contributions, non-linear elements, and more). As such, they provide useful results and insight for the development and design of future LLRF feedback systems. They also provide the opportunity to study diverse longitudinal beam dynamics effects such as coupled-bunch impedance driven instabilities and single bunch longitudinal emittance growth. Coupled-bunch instabilities and RF station power were the performance limiting effects for PEP-II. The sensitivity of the instabilities to individual LLRF parameters, the effectiveness of alternative operational algorithms, and the possible tradeoffs between RF loop and beam stability were studied. New algorithms were implemented, with significant performance improvement leading to a world record current during the last PEP-II run of 3212 mA for the Low Energy Ring. Longitudinal beam emittance growth due to RF noise is a major concern for LHC. Simulations studies and measurements were conducted that clearly show the correlation between RF noise and longitudinal bunch emittance, identify the major LLRF noise contributions, and determine the RF component dominating this effect. With these results, LHC upgrades and alternative algorithms are evaluated to reduce longitudinal emittance growth during operations. The applications of this work are described with regard to future machines and analysis of new technical implementations, as well as to possible future work which would continue the directions of this dissertation.
Mastoridis, Themistoklis; /Stanford U., Elect. Eng. Dept. /SLAC
Science Conference Proceedings (OSTI)
The number of sources of radio-frequency (RF) electromagnetic fields in our midst has increased dramatically in the past three decades.�From cordless phones, to cellular phones and their base stations, to pagers and walkie-talkies, to WiFi in public venues, such as coffee shops and airports, and to smart meters and other wireless components of the smart grid.�Of course, since the advent of broadcast radio and TV during the 20th century, radio-frequency electromagnetic fields have been an ...
Energy Saving Glass Lamination via Selective Radio Frequency Heating
This project focused on advancing radio-frequency (RF) lamination technology closer to commercial implementation, in order to reduce the energy intensity of glass lamination by up to 90%. Lamination comprises a wide range of products including autoglass, architectural safety and innovative design glass, transparent armor (e.g. bullet proof glass), smart glass, mirrors, and encapsulation of photovoltaics. Lamination is also the fastest growing segment of glass manufacturing, with photovoltaics, architectural needs, and an anticipated transition to laminated side windows in vehicles. The state-of-the-art for glass lamination is to use autoclaves, which apply heat and uniform gas pressure to bond the laminates over the course of 1 to 18 hours. Laminates consist of layers of glass or other materials bonded with vinyl or urethane interlayers. In autoclaving, significant heat energy is lost heating the chamber, pressurized air, glass racks, and the glass. In RF lamination, the heat is generated directly in the vinyl interlayer, causing it to heat and melt quickly, in just 1 to 10 minutes, without significantly heating the glass or the equipment. The main purpose of this project was to provide evidence that low energy, rapid RF lamination quality met the same standards as conventionally autoclaved windows. The development of concepts for laminating curved glass with RF lamination was a major goal. Other primary goals included developing a stronger understanding of the lamination product markets described above, and to refine the potential benefits of commercial implementation. The scope of the project was to complete implementation concept studies in preparation for continuation into advanced development, pilot studies, and commercial implementation. The project consisted of 6 main tasks. The first dealt with lamination with poly-vinyl butyral (PVB) interlayers, which prior work had shown difficulties in achieving good quality laminates, working with Pilkington North America. The second task dealt with a study of current lamination processes in the various laminate industries, and development of concepts for integrating RF lamination into new or existing processes. The third task explored the use of a non-destructive technique for analyzing laminate adhesion with the University of Illinois at Urbana-Champaign. The fourth task focused on developing concepts for curved glass lamination using RF lamination. The fifth and sixth tasks together comprised an analysis of laminate product markets, ranking for applicability and commercialization potential, and the development of commercialization strategies for those products. In addition, throughout the project as new experimental data and conventional process data were obtained, the benefits analysis of RF lamination was refined. The goals of the project described above were achieved, positioning RF lamination for the next stage growth envisioned in the original Industrial Grand Challenge proposal. Working with Pilkington North America, lamination of flat autoglass with PVB was achieved, meeting all 16 stringent industry tests. In particular, PVB laminates made with RF lamination passed environmental tests including the high temperature, 120 C bake test, without significant formation of bubbles (defects). The adhesion of PVB to glass was measured using the pummel method. Adhesion values ranging from 1 to 7 out of 10 were obtained. The significant process parameters affecting the environmental and adhesion performance were identified through a designed experiment. Pre-lamination process variables including PVB storage humidity and the de-airing process (vacuum or nip rolling) were significant, as well as the level of pressure applied to the laminate during the RF process. Analysis of manufacturing with RF lamination equipment, based on the processes developed indicated that 3 RF presses could replace a typical auto-industry autoclave to achieve equal or greater throughput with possibly less capital cost and smaller footprint. Concepts for curved lamination identifying castable molds for
Allan, Shawn M.
Energy Saving Glass Lamination via Selective Radio Frequency Heating
This project focused on advancing radio-frequency (RF) lamination technology closer to commercial implementation, in order to reduce the energy intensity of glass lamination by up to 90%. Lamination comprises a wide range of products including autoglass, architectural safety and innovative design glass, transparent armor (e.g. bullet proof glass), smart glass, mirrors, and encapsulation of photovoltaics. Lamination is also the fastest growing segment of glass manufacturing, with photovoltaics, architectural needs, and an anticipated transition to laminated side windows in vehicles. The state-of-the-art for glass lamination is to use autoclaves, which apply heat and uniform gas pressure to bond the laminates over the course of 1 to 18 hours. Laminates consist of layers of glass or other materials bonded with vinyl or urethane interlayers. In autoclaving, significant heat energy is lost heating the chamber, pressurized air, glass racks, and the glass. In RF lamination, the heat is generated directly in the vinyl interlayer, causing it to heat and melt quickly, in just 1 to 10 minutes, without significantly heating the glass or the equipment. The main purpose of this project was to provide evidence that low energy, rapid RF lamination quality met the same standards as conventionally autoclaved windows. The development of concepts for laminating curved glass with RF lamination was a major goal. Other primary goals included developing a stronger understanding of the lamination product markets described above, and to refine the potential benefits of commercial implementation. The scope of the project was to complete implementation concept studies in preparation for continuation into advanced development, pilot studies, and commercial implementation. The project consisted of 6 main tasks. The first dealt with lamination with poly-vinyl butyral (PVB) interlayers, which prior work had shown difficulties in achieving good quality laminates, working with Pilkington North America. The second task dealt with a study of current lamination processes in the various laminate industries, and development of concepts for integrating RF lamination into new or existing processes. The third task explored the use of a non-destructive technique for analyzing laminate adhesion with the University of Illinois at Urbana-Champaign. The fourth task focused on developing concepts for curved glass lamination using RF lamination. The fifth and sixth tasks together comprised an analysis of laminate product markets, ranking for applicability and commercialization potential, and the development of commercialization strategies for those products. In addition, throughout the project as new experimental data and conventional process data were obtained, the benefits analysis of RF lamination was refined. The goals of the project described above were achieved, positioning RF lamination for the next stage growth envisioned in the original Industrial Grand Challenge proposal. Working with Pilkington North America, lamination of flat autoglass with PVB was achieved, meeting all 16 stringent industry tests. In particular, PVB laminates made with RF lamination passed environmental tests including the high temperature, 120 �?�?�?°C bake test, without significant formation of bubbles (defects). The adhesion of PVB to glass was measured using the pummel method. Adhesion values ranging from 1 to 7 out of 10 were obtained. The significant process parameters affecting the environmental and adhesion performance were identified through a designed experiment. Pre-lamination process variables including PVB storage humidity and the de-airing process (vacuum or nip rolling) were significant, as well as the level of pressure applied to the laminate during the RF process. Analysis of manufacturing with RF lamination equipment, based on the processes developed indicated that 3 RF presses could replace a typical auto-industry autoclave to achieve equal or greater throughput with possibly less capital cost and smaller footprint. Concepts for curved lamination id
Allan, Shawn M.; Baranova, Inessa; Poley, Joseph; Reis, Henrique
Electronic and Embedded Systems Low-frequency radio identification
-cost hardware and easy installation. Users: Stewards of high-valued assets, protective forces, DOE, NNSA, DOD
Science Conference Proceedings (OSTI)
Self-excited plasma series resonance is observed in low pressure capacitvely coupled radio frequency discharges as high-frequency oscillations superimposed on the normal radio frequency current. This high-frequency contribution to the radio frequency current is generated by a series resonance between the capacitive sheath and the inductive and resistive bulk plasma. In this report, we present an experimental method to measure the plasma series resonance in a capacitively coupled radio frequency argon plasma by modifying the homogeneous discharge model. The homogeneous discharge model is modified by introducing a correction factor to the plasma resistance. Plasma parameters are also calculated by considering the plasma series resonances effect. Experimental measurements show that the self-excitation of the plasma series resonance, which arises in capacitive discharge due to the nonlinear interaction of plasma bulk and sheath, significantly enhances both the Ohmic and stochastic heating. The experimentally measured total dissipation, which is the sum of the Ohmic and stochastic heating, is found to increase significantly with decreasing pressure.
Bora, B.; Bhuyan, H.; Favre, M.; Wyndham, E.; Chuaqui, H. [Facultad de Fisica, Pontificia Universidad Catolica de Chile, Ave. Vicuna Mackenna 4860, Santiago 22 (Chile); Kakati, M. [Thermal Plasma Processed Materials Laboratory, Centre of Plasma Physics, Institute for Plasma Research, Sonapur 782 402, Assam (India)
Science Conference Proceedings (OSTI)
Advanced Metering Infrastructure (AMI) is rapidly expanding to improve the service quality and efficiency of our electrical power systems. This short paper focuses on questions that have arisen with regard to residential radio-frequency exposure from Automatic Meter Reading technology (or the use of so-called Smart Meters), a component of AMI, which over time is replacing conventional electrical meters.
The effect of radio frequency plasma processing reactor circuitry on plasma characteristics
, developed an equivalent circuit model of the plasma reactor using this data, and later devel- oped a sheath was supported by the National Institute of Standards and Technology, Air Force Office of Scientific ResearchThe effect of radio frequency plasma processing reactor circuitry on plasma characteristics Shahid
Kushner, Mark
Radio frequency circuits for wireless receiver front-ends
The beginning of the 21st century sees great development and demands on wireless communication technologies. Wireless technologies, either based on a cable replacement or on a networked environment, penetrate our daily life more rapidly than ever. Low operational power, low cost, small form factor, and function diversity are the crucial requirements for a successful wireless product. The receiver??s front-end circuits play an important role in faithfully recovering the information transmitted through the wireless channel. Bluetooth is a short-range cable replacement wireless technology. A Bluetooth receiver architecture was proposed and designed using a pure CMOS process. The front-end of the receiver consists of a low noise ampli?er (LNA) and mixer. The intermediate frequency was chosen to be 2MHz to save battery power and alleviate the low frequency noise problem. A conventional LNA architecture was used for reliability. The mixer is a modi?ed Gilbert-cell using the current bleeding technique to further reduce the low frequency noise. The front-end draws 10 mA current from a 3 V power supply, has a 8.5 dB noise ?gure, and a voltage gain of 25 dB and -9 dBm IIP3. A front-end for dual-mode receiver is also designed to explore the capability of a multi-standard application. The two standards are IEEE 802.11b and Bluetooth. They work together making the wireless experience more exciting. The front-end is designed using BiCMOS technology and incorporating a direct conversion receiver architecture. A number of circuit techniques are used in the front-end design to achieve optimal results. It consumes 13.6 mA from a 2.5 V power supply with a 5.5 dB noise ?gure, 33 dB voltage gain and -13 dBm IIP3. Besides the system level contributions, intensive studies were carried out on the development of quality LNA circuits. Based on the multi-gated LNA structure, a CMOS LNA structure using bipolar transistors to provide linearization is proposed. This LNA con?guration can achieve comparable linearity to its CMOS multi-gated counterpart and work at a higher frequency with less power consumption. A LNA using an on-chip transformer source degeneration is proposed to realize input impedance matching. The possibility of a dual-band cellular application is studied. Finally, a study on ultra-wide band (UWB) LNA implementation is performed to explore the possibility and capability of CMOS technology on the latest UWB standard for multimedia applications.
Xin, Chunyu
Science Conference Proceedings (OSTI)
We process solar flare observations of Nobeyama Radio Polarimeters with an improved maximum likelihood method developed recently by Clauset et al. The method accurately extracts power-law behaviors of the peak fluxes in 486 radio bursts at six frequencies (1-35 GHz) and shows an excellent performance in this study. The power-law indices on 1-35 GHz given by this study vary around 1.74-1.87, which is consistent with earlier statistics in different solar cycles and very close to the simulations of the avalanche model by Lu.
Song Qiwu; Huang Guangli [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Tan Baolin, E-mail: email@example.com, E-mail: firstname.lastname@example.com, E-mail: email@example.com [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)
Characterization of Radio Frequency Emissions From Two Models of Wireless Smart Meters
Science Conference Proceedings (OSTI)
Concomitant with the widespread deployment of Advanced Metering Infrastructure (AMI) is the need to characterize radio-frequency (RF) emissions from wireless smart meters. A previous EPRI Technical Report (1021126) provided a detailed characterization of RF emissions from one type of wireless smart meter deployed across several service territories in the U.S. This report describes emissions from wireless smart meters produced by two manufacturers that are currently in operation within a large service ter...
We present the first spectroscopic images of solar radio transients from the prototype for the Murchison Widefield Array, observed on 2010 March 27. Our observations span the instantaneous frequency band 170.9�201.6 MHz. ...
Oberoi, Divya
On the application of radio frequency voltages to ion traps via helical resonators
Ions confined using a Paul trap require a stable, high voltage and low noise radio frequency (RF) potential. We present a guide for the design and construction of a helical coil resonator for a desired frequency that maximises the quality factor for a set of experimental constraints. We provide an in-depth analysis of the system formed from a shielded helical coil and an ion trap by treating the system as a lumped element model. This allows us to predict the resonant frequency and quality factor in terms of the physical parameters of the resonator and the properties of the ion trap. We also compare theoretical predictions with experimental data for different resonators, and predict the voltage applied to the ion trap as a function of the Q-factor, input power and the properties of the resonant circuit.
Siverns, J D; Weidt, S; Hensinger, W K
On the application of radio frequency voltages to ion traps via helical resonators
Ions confined using a Paul trap require a stable, high voltage and low noise radio frequency (RF) potential. We present a guide for the design and construction of a helical coil resonator for a desired frequency that maximises the quality factor for a set of experimental constraints. We provide an in-depth analysis of the system formed from a shielded helical coil and an ion trap by treating the system as a lumped element model. This allows us to predict the resonant frequency and quality factor in terms of the physical parameters of the resonator and the properties of the ion trap. We also compare theoretical predictions with experimental data for different resonators, and predict the voltage applied to the ion trap as a function of the Q-factor, input power and the properties of the resonant circuit.
J. D. Siverns; L. R. Simkins; S. Weidt; W. K. Hensinger
A description is given of the ferrite biasing system for the four tuned radio frequency cavities of the synchrotron. Each ferrite loaded double cavity has a single turn bias winding which is driven to a peak current of 13,500 amperes by a push-pull transformer arrangement. There is automatic tap changing of the transformer to accommodate the variable impedance load (for power considerations). The programming and frequency response of the system have to be such that each cavity can operate as the reso nant circuit of a self tracking radio frequency amplifier over the frequency range 6.5 to 30 Mc at the 20 cps repetition rate of the synchrotron. Between acceleration cycles it is necessary to program the ferrite to a given magnetic state, near that of maximum radio frequency permeability. (auth)
Rees, G.H.
Simulation of an RFQ (radio-frequency quadruple) funnel for heavy-ion beams
Science Conference Proceedings (OSTI)
Use of the magnetic force to focus and deflect heavy-ion beams is marginal at low ion velocities. Low-emittance-growth funnels using discrete magnetic elements are difficult to design for these beams. We show that a new type of radio-frequency quadruple (RFQ) funnel is especially suitable for this application. Simulation procedures, which include space-charge and image effects, have produced a high-quality funnel design for 20-MeV Bi/sup +1/ ions. 4 refs., 4 figs., 2 tabs.
Guy, F.W.; Stokes, R.H.
Vane fabrication for the proof-of-principle radio-frequency quadrupole accelerator
The electrodes for the Proof-of-Principle (POP) Radio-Frequency Quadrupole (RFQ) accelerator were machined on a numerically controlled, three-axis, vertical mill. These pole tips, or vanes, were prepared for, and used, in the successful demonstration of RFQ practicality at Los Alamos National Laboratory in February 1980. The data set that described the vanes contained about 10 million bits of tool position data. The vanes were cut from OFHC copper blanks. The tolerances achieved were approximately +- 0.005 cm. The design and manufacturing procedures are described.
Williams, S.W.; Potter, J.M.
A prototype system for detecting the radio-frequency pulse associated with cosmic ray air showers
The development of a system to detect the radio-frequency (RF) pulse associated with extensive air showers of cosmic rays is described. This work was performed at the CASA/MIA array in Utah, with the intention of designing equipment that can be used in conjunction with the Auger Giant Array. A small subset of data (less than 40 out of a total of 600 hours of running time), taken under low-noise conditions, permitted upper limits to be placed on the rate for pulses accompanying showers of energies around $10^{17}$ eV.
Kevin Green; Jonathan L. Rosner; Denis A. Suprun; J. F. Wilkerson
A new Main Injector radio frequency system for 2.3 MW Project X operations
For Project X Fermilab Main Injector will be required to provide up to 2.3 MW to a neutrino production target at energies between 60 and 120 GeV. To accomplish the above power levels 3 times the current beam intensity will need to be accelerated. In addition the injection energy of Main Injector will need to be as low as 6 GeV. The current 30 year old Main Injector radio frequency system will not be able to provide the required power and a new system will be required. The specifications of the new system will be described.
Dey, J.; Kourbanis, I.; /Fermilab
Radio Frequency Phototube, Optical Clock and Precise Measurements in Nuclear Physics
Recently a new experimental program of novel systematic studies of light hypernuclei using pionic decay was established at JLab (Study of Light Hypernuclei by Pionic Decay at JLab, JLab Experiment PR-08-012). The highlights of the proposed program include high precision measurements of binding energies of hypernuclei by using a high resolution pion spectrometer, HpiS. The average values of binding energies will be determined within an accuracy of ~10 keV or better. Therefore, the crucial point of this program is an absolute calibration of the HpiS with accuracy 10E-4 or better. The merging of continuous wave laser-based precision optical-frequency metrology with mode-locked ultrafast lasers has led to precision control of the visible frequency spectrum produced by mode-locked lasers. Such a phase-controlled mode-locked laser forms the foundation of an optical clock or femtosecond optical frequency comb (OFC) generator, with a regular comb of sharp lines with well defined frequencies. Combination of this technique with a recently developed radio frequency (RF) phototube results in a new tool for precision time measurement. We are proposing a new time-of-flight (TOF) system based on an RF phototube and OFC technique. The proposed TOF system achieves 10 fs instability level and opens new possibilities for precise measurements in nuclear physics such as an absolute calibration of magnetic spectrometers within accuracy 10E-4 - 10E-5.
Amur Margaryan
Small Satellite Applications of Commercial off the Shelf Radio Frequency Integrated Circuits
Within the first decade of the 21st century, the aerospace community has seen many more opportunities to launch small spacecraft in the 10 to 100 kg mass class. Coupled with this has been consistent interest from the government in developing small-spacecraft platforms to expand civil and military mission possibilities. Small spacecraft have also given small organizations such as universities an increased access to space. Because small satellites are limited in size, power, and mass, new and often nontraditional capabilities must be explored and developed to make them viable and attractive when compared with larger and more proven spacecraft. Moreover, small organizations that wish to contribute technically are often limited by the small size of their teams and available resources, and need creative solutions for meeting mission requirements. A key need is in space-to-ground communications. Complex missions typically require large amounts of data transfer to the ground and in a timely fashion. Available options trade hardware cost, available ground stations or networks, available operating-frequency range, data-rate performance, and ease of use. A system for small spacecraft will be presented based upon Radio Frequency Integrated Circuits (RFIC) that minimizes development effort and maximizes interface control to meet typical small-spacecraft communications requirements. RFICs are low-cost components that feature pre-built radio hardware on a chip that can be expanded easily by developers with little or no radio experience. These devices are widespread in domestic applications for short-range connectivity. A preliminary design and prototype is presented that meets basic spaceflight requirements, offers data rates in the 55 to 85 kbps range, and has completed basic proof-of-concept testing. While there are higher-data-rate alternatives in existence, the solution presented here strikes a useful balance among data rate, parts cost, and ease of use for non experts, and gives the user operational control necessary to make air-to-ground communications time effective.
Graves, John
Collisionless electron heating by radio frequency bias in low gas pressure inductive discharge
We show experimental observations of collisionless electron heating by the combinations of the capacitive radio frequency (RF) bias power and the inductive power in low argon gas pressure RF biased inductively coupled plasma (ICP). With small RF bias powers in the ICP, the electron energy distribution (EED) evolved from bi-Maxwellian distribution to Maxwellian distribution by enhanced plasma bulk heating and the collisionless sheath heating was weak. In the capacitive RF bias dominant regime, however, high energy electrons by the RF bias were heated on the EEDs in the presence of the ICP. The collisionless heating mechanism of the high energy electrons transited from collisionless inductive heating to capacitive coupled collisionless heating by the electron bounce resonance in the RF biased ICP.
Lee, Hyo-Chang; Chung, Chin-Wook [Department of Electrical Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)
Supersonic combustion of a transverse injected H sub 2 jet in a radio frequency heated flow
The combustion of a single hydrogen jet, normally injected into a radio frequency (RF) heated, oxidant-containing, supersonic flow, has been established to characterize the chemical and fluid dynamic phenomena associated with the reaction process and ultimately validate the predictive capability of computational computer dynamic (CFD) codes. The experimental system employed for this study is unique in that it uses an electrodeless, inductively coupled plasma tube to generate the high temperature oxidant-containing gas for subsequent nozzle expansion. Advantages of an RF heated flow system include reduced free-stream chemical contamination, continuous operation, and relative ease of integration into a typical flow laboratory environment. A description of the system utilized for this study is presented including preliminary results of the reactive flow characterization. In addition, the use of the laser-based diagnostic techniques, such as planar laser-induced fluorescence (PLIF), for measuring flow properties is also discussed. 8 refs., 7 figs.
Wantuck, P.J.; Tennant, R.A.; Watanabe, H.H.
Laser polishing of niobium for application to superconducting radio frequency cavities
Superconducting radio frequency niobium cavities are at the heart of an increasing number of particle accelerators. Their performance is dominated by a several nanometer thick layer at the interior surface. Maximizing the smoothness of this surface is critical, and aggressive chemical treatments are now employed to this end. The authors describe laser-induced surface melting as an alternative �greener� approach. Selection of laser parameters guided by modeling achieved melting that reduced the surface roughness from the fabrication process. The resulting topography was examined by scanning electron microscope and atomic force microscope (AFM). Plots of power spectral density computed from the AFM data give further insight into the effect of laser melting on the topography of the mechanically polished (only) niobium.
Senthil Singaravelu ,John Klopf, Chen Xu, Geoffrey Krafft, Michael Kelley
Science Conference Proceedings (OSTI)
We present the results of from DC magnetization and penetration depth measurements of cylindrical bulk large-grain (LG) and fine-grain (FG) niobium samples used for the fabrication of superconducting radio frequency (SRF) cavities. The surface treatment consisted of electropolishing and low temperature baking as they are typically applied to SRF cavities. The magnetization data were fitted using a modified critical state model. The critical current density Jc and pinning force Fp are calculated from the magnetization data and their temperature dependence and field dependence are presented. The LG samples have lower critical current density and pinning force density compared to FG samples which implies a lower flux trapping efficiency. This effect may explain the lower values of residual resistance often observed in LG cavities than FG cavities.
Dhavale Ashavai, Pashupati Dhakal, Anatolii A Polyanskii, Gianluigi Ciovati
Coupled microwave ECR and radio-frequency plasma source for plasma processing
In a dual plasma device, the first plasma is a microwave discharge having its own means of plasma initiation and control. The microwave discharge operates at electron cyclotron resonance (ECR), and generates a uniform plasma over a large area of about 1000 cm.sup.2 at low pressures below 0.1 mtorr. The ECR microwave plasma initiates the second plasma, a radio frequency (RF) plasma maintained between parallel plates. The ECR microwave plasma acts as a source of charged particles, supplying copious amounts of a desired charged excited species in uniform manner to the RF plasma. The parallel plate portion of the apparatus includes a magnetic filter with static magnetic field structure that aids the formation of ECR zones in the two plasma regions, and also assists in the RF plasma also operating at electron cyclotron resonance.
Tsai, Chin-Chi (Oak Ridge, TN); Haselton, Halsey H. (Knoxville, TN)
Coupled microwave ECR and radio-frequency plasma source for plasma processing
In a dual plasma device, the first plasma is a microwave discharge having its own means of plasma initiation and control. The microwave discharge operates at electron cyclotron resonance (ECR), and generates a uniform plasma over a large area of about 1000 cm[sup 2] at low pressures below 0.1 mtorr. The ECR microwave plasma initiates the second plasma, a radio frequency (RF) plasma maintained between parallel plates. The ECR microwave plasma acts as a source of charged particles, supplying copious amounts of a desired charged excited species in uniform manner to the RF plasma. The parallel plate portion of the apparatus includes a magnetic filter with static magnetic field structure that aids the formation of ECR zones in the two plasma regions, and also assists in the RF plasma also operating at electron cyclotron resonance. 4 figures.
Tsai, C.C.; Haselton, H.H.
Temperature distributions of radio-frequency plasma in water by spectroscopic analysis
Science Conference Proceedings (OSTI)
Distributions of emission intensity from radicals, electron temperature, and rotational temperature at a radio frequency of 27.12 MHz plasma in water are clarified by detailed spectroscopy measurement. Through this investigation, the following were observed. The points of maximum emission intensity of Halpha, Hbeta, O (777 nm), and O (845 nm) are almost the same, while that of OH shifts upward. The electron temperature decreases, while the rotational temperature increases with pressure. The distribution of the electron temperature changes at a threshold pressure, which is concerned with a change in the electron discharge mechanism. The self-bias of the electrode changes from a negative to positive at a threshold pressure. The point of the maximum rotational temperature of OH radicals shifts to approximately 1 mm above that for the maximum intensity of OH emission.
Mukasa, Shinobu; Nomura, Shinfuku; Toyota, Hiromichi; Maehara, Tsunehiro; Abe, Fumiaki [Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama 790-8577 (Japan); Kawashima, Ayato [Faculty of Agriculture, Ehime University, Matsuyama 790-8566 (Japan)
Radio Frequency Noise Effects on the CERN Large Hadron Collider Beam Diffusion
Radio frequency (rf) accelerating system noise can have a detrimental impact on the Large Hadron Collider (LHC) performance through longitudinal motion and longitudinal emittance growth. A theoretical formalism has been developed to relate the beam and rf station dynamics with the bunch length growth. Measurements were conducted at LHC to determine the performance limiting rf components and validate the formalism through studies of the beam diffusion dependence on rf noise. As a result, a noise threshold was established for acceptable performance which provides the foundation for beam diffusion estimates for higher energies and intensities. Measurements were also conducted to determine the low level rf noise spectrum and its major contributions, as well as to validate models and simulations of this system.
Mastoridis, T.; Baudrenghien, P.; Butterworth, A.; Molendijk, J.; /CERN; Rivetta, C.; Fox, J.D.; /SLAC
A radio frequency (RF) dielectric heater has been developed for isolating thermal and nonthermal effects of RF energy on microorganisms in liquid foods. The modified heater enables the simultaneous application of RF energy and removal of thermal energy from the liquids. A double-pipe heat exchanger is an integral part of the heater. The outer pipe is made of Teflon. The inner pipe is made of stainless steel that is grounded in the RF circuit. Liquid food flows through the annular region between the two concentric pipes. Cooling water flows through the stainless steel pipe. The food in the annular region absorbs the RF energy. Concurrently, the cooling water flowing in the inner pipe removes the thermal energy from the food, thus controlling the temperature.
D.J. Geveke; M. Kozempel; C. Brunkhorst
Low-Level Radio Frequency System Development for the National Synchrotron Light Source II
The National Synchrotron Light Source-II (NSLS-II) is a new ultra-bright 3GeV 3rd generation synchrotron radiation light source. The performance goals require operation with a beam current of 500mA and a bunch current of at least 0.5mA. The position and timing specifications of the ultra-bright photon beam imposes a set of stringent requirements on the performance of radio frequency (RF) control. In addition, commissioning and staged installation of damping wigglers and insertion devices requires the flexibility of handling varying beam conditions. To meet these requirements, a digital implementation of the LLRF is chosen, and digital serial links are planned for the system integration. The first prototype of the controller front-end hardware has been built, and is currently being tested.
Ma,H.; Rose, J.
Electromagnetic and mechanical design of gridded radio-frequency cavity windows
Electromagnetic, thermal and structural analyses of radio-frequency (RF) cavities were performed as part of a developmental RF cavity program for muon cooling. RF cavities are necessary to provide longitudinal focusing of the muons and to compensate for their energy loss. Closing the cavity ends by electrically conducting windows reduces the power requirement and increases the on-axis electric field for a given maximum surface electric field. Many factors must be considered in the design of RF cavity windows. RF heating can cause the windows to deform in the axial direction of the cavity. The resulting thermal stresses in the window must be maintained below the yield stress of the window material. The out-of-plane deflection must be small enough so that the consequent frequency shift is tolerable. For example, for an 805 MHz cavity, the out-of-plane deflection must be kept below 25 microns to prevent the frequency of the cavity from shifting more than 10 kHz. In addition, the window design should yield smooth electric and magnetic fields, terminate field leakage beyond the window, and minimize beam scattering. In the present thesis, gridded-tube window designs were considered because of their high structural integrity. As a starting point in the analysis, a cylindrical pillbox cavity was considered as a benchmark problem. Analytical and finite element solutions were obtained for the electric and magnetic fields, power loss density, and temperature profile. Excellent agreement was obtained between the analytical and finite element results. The finite element method was then used to study a variety of gridded-tube windows. It was found that cooling of the gridded-tube windows by passing helium gas inside the tubes significantly reduces the out-of-plane deflection and the thermal stresses. Certain tube geometries and grid patterns were found to satisfy all of the design requirements.
Alsharoa, Mohammad M.; /IIT, Chicago /Fermilab
The national livestock identification system: the importance of traceability in E-business
Science Conference Proceedings (OSTI)
This paper aims to explore how Radio Frequency Identification (RFID) can be utilized on dairy farms to enhance total farm management. There is a growing worldwide trend for countries to implement whole-of-life traceability systems for livestock, and ... Keywords: livestock, radio frequency identification, total farm management, traceability
Adam Trevarthen
Radio frequency pulse compression experiments at SLAC (Stanford Linear Accelerator Center)
Science Conference Proceedings (OSTI)
Proposed future positron-electron linear colliders would be capable of investigating fundamental processes of interest in the 0.5--5 TeV beam-energy range. At the SLAC Linear Collider (SLC) gradient of about 20 MV/m this would imply prohibitive lengths of about 50--250 kilometers per linac. We can reduce the length by increasing the gradient but this implies high peak power, on the order of 400-- to 1000-MW at X-Band. One possible way to generate high peak power is to generate a relatively long pulse at a relatively low power and compress it into a short pulse with higher peak power. It is possible to compress before DC to RF conversion, as is done using magnetic switching for induction linacs, or after DC to RF conversion, as is done for the SLC. Using RF pulse compression it is possible to boost the 50-- to 100-MW output that has already been obtained from high-power X-Band klystrons the levels required by the linear colliders. In this note only radio frequency pulse compression (RFPC) is considered.
Farkas, Z.D.; Lavine, T.L.; Menegat, A.; Miller, R.H.; Nantista, C.; Spalek, G.; Wilson, P.B.
Characterization of nonthermal Ne-N{sub 2} mixture radio frequency discharge
Science Conference Proceedings (OSTI)
This paper deals with optical emission spectroscopic studies of low pressure (p=0.1{yields}0.5 mbar) Ne-N{sub 2} capacitively coupled radio frequency (rf) plasma that can be used for plasma nitriding, etc. It reports the methods to calculate the electron temperature (T{sub e}) in nonthermal plasmas. Since, the selected Ne I lines, used to calculate electron temperature, are found in corona balance; therefore, it allows us to use modified Boltzmann technique to calculate electron temperature. Langmuir probe is also used to calculate electron temperature and electron energy distribution functions (EEDFs). The measurements are worked out for different discharge parameters like neon percentage, filling pressure and RF power. It is found that electron temperature increases with the increase in neon percentage and decreases with the increase in pressure, whereas excitation temperature (T{sub exc}) increases with power, neon percentage, and decreases with pressure. It is also observed that electron temperature measured by Langmuir probe technique is slightly greater than the one measured via modified Boltzmann plot method. The tails of the EEDFs gain height and extend toward the higher energy with the increase in neon percentage in the mixture.
Rehman, N. U.; Zakaullah, M. [Department of Physics, Quaid-i-Azam University, 45320 Islamabad (Pakistan); Khan, F. U. [Department of Physics, Gomal University, 29050 D.I. Khan (Pakistan); Naseer, S. [Department of Physics, Peshawar University, 25120 Peshawar (Pakistan)
Development of Ultra High Gradient and High Q{sub 0} Superconducting Radio Frequency Cavities
We report on the recent progress at Jefferson Lab in developing ultra high gradient and high Q{sub 0} superconducting radio frequency (SRF) cavities for future SRF based machines. A new 1300 MHz 9-cell prototype cavity is being fabricated. This cavity has an optimized shape in terms of the ratio of the peak surface field (both magnetic and electric) to the acceleration gradient, hence the name low surface field (LSF) shape. The goal of the effort is to demonstrate an acceleration gradient of 50 MV/m with Q{sub 0} of 10{sup 10} at 2 K in a 9-cell SRF cavity. Fine-grain niobium material is used. Conventional forming, machining and electron beam welding method are used for cavity fabrication. New techniques are adopted to ensure repeatable, accurate and inexpensive fabrication of components and the full assembly. The completed cavity is to be first mechanically polished to a mirror-finish, a newly acquired in-house capability at JLab, followed by the proven ILC-style processing recipe established already at JLab. In parallel, new single-cell cavities made from large-grain niobium material are made to further advance the cavity treatment and processing procedures, aiming for the demonstration of an acceleration gradient of 50 MV/m with Q{sub 0} of 2?10{sup 10} at 2K.
Geng, Rongli [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Clemens, William A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Follkie, James E. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Harris, Teena M. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Kushnick, Peter W. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Machie, Danny [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Martin, Robert E. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Palczewski, Ari D. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Perry, Era A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Slack, Gary L. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Williams, R. S. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Adolphsen, C. [SLAC, Menlo Park, California, (United States); Li, Z. [SLAC, Menlo Park, California, (United States); Hao, J. K. [Peking University, Beijing (China); Li, Y. M. [Peking University, Beijing (China); Liu, K. X. [Peking University, Beijing (China)
Method of making radio frequency ion source antenna and such antenna
In the method, the radio frequency (rf) antenna is made by providing a clean coil made of copper tubing or other metal conductor, which is coated with a tacky organic binder, and then with a powdered glass frit, as by sprinkling the frit uniformly over the binder. The coil is then heated internally in an inert gas atmosphere, preferably by passing an electrical heating current along the coil. Initially, the coil is internally heated to about 200/sup 0/C to boil off the water from the binder, and then to about 750 to 850/sup 0/C to melt the glass frit, while also burning off the organic binder. The melted frit forms a molten glass coating on the metal coil, which is then cooled to solidify the glass, so that the metal coil is covered with a thin continuous homogeneous impervious glass coating of substantially uniform thickness. The glass coating affords complete electrical insulation and complete dielectric protection for the metal coil of the rf antenna, to withstand voltage breakdown and to prevent sputtering, while also doubling the plasma generating efficiency of the rf antenna, when energized with RF power in the vacuum chamber of an ion source for a particle accelerator or the like. The glass frit preferably contains approximately 45% lead oxide.
Ehlers, K.W.; Leung, K.N.
Particles are generated in low pressure radio frequency (13.56 MHz) CH{sub 4}/N{sub 2} discharges containing 90% of nitrogen. The influence of the radio frequency power supply on the particle presence within the plasma is studied. Particles are evidenced by laser light scattering. The particle formation leads to modifications in the discharge electrical parameters such as the dc self-bias voltage and the phase angle third harmonic. The plasma is analyzed by optical emission spectroscopy by following the temporal evolution of excited species such as CN, N{sub 2}, N{sub 2}{sup +}, Ar, and He. Finally, the particle morphology and size are analyzed by scanning electron microscopy. The correlation between these results allows a better understanding of the power influence on the particle growth within the plasma.
Massereau-Guilbaud, Veronique; Pereira, Jeremy; Geraud-Grenier, Isabelle; Plain, Andre [GREMI, Groupe de Recherches sur l'Energetique des Milieux Ionises, UMR6606, CNRS/Universite d' Orleans, Site de Bourges, Rue G. Berger, BP 4043, 18028 Bourges Cedex (France)
Throughput and delay analysis for hybrid radio-frequency and free-space-optical (RF/FSO) networks
Science Conference Proceedings (OSTI)
In this paper the per-node throughput and end-to-end delay of randomly deployed (i.e. ad-hoc) hybrid radio frequency - free space optics (RF/FSO) networks are studied. The hybrid RF/FSO network consists of an RF ad hoc network of n nodes, f(n) ... Keywords: Ad hoc networks, Delay, Free space optics, Hybrid networks, Throughput capacity
Di Wang; Alhussein A. Abouzeid
H{sup -} radio frequency source development at the Spallation Neutron Source
Science Conference Proceedings (OSTI)
The Spallation Neutron Source (SNS) now routinely operates nearly 1 MW of beam power on target with a highly persistent {approx}38 mA peak current in the linac and an availability of {approx}90%. H{sup -} beam pulses ({approx}1 ms, 60 Hz) are produced by a Cs-enhanced, multicusp ion source closely coupled with an electrostatic low energy beam transport (LEBT), which focuses the 65 kV beam into a radio frequency quadrupole accelerator. The source plasma is generated by RF excitation (2 MHz, {approx}60 kW) of a copper antenna that has been encased with a thickness of {approx}0.7 mm of porcelain enamel and immersed into the plasma chamber. The ion source and LEBT normally have a combined availability of {approx}99%. Recent increases in duty-factor and RF power have made antenna failures a leading cause of downtime. This report first identifies the physical mechanism of antenna failure from a statistical inspection of {approx}75 antennas which ran at the SNS, scanning electron microscopy studies of antenna surface, and cross sectional cuts and analysis of calorimetric heating measurements. Failure mitigation efforts are then described which include modifying the antenna geometry and our acceptance/installation criteria. Progress and status of the development of the SNS external antenna source, a long-term solution to the internal antenna problem, are then discussed. Currently, this source is capable of delivering comparable beam currents to the baseline source to the SNS and, an earlier version, has briefly demonstrated unanalyzed currents up to {approx}100 mA (1 ms, 60 Hz) on the test stand. In particular, this paper discusses plasma ignition (dc and RF plasma guns), antenna reliability, magnet overheating, and insufficient beam persistence.
Welton, R. F.; Gawne, K. R.; Han, B. X.; Murray, S. N.; Pennisi, T. R.; Roseberry, R. T.; Santana, M.; Stockli, M. P. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37830-6471 (United States); Dudnikov, V. G. [Muons, Inc., 552 N. Batavia Avenue, Batavia, Illinois 60510 (United States); Turvey, M. W. [Villanova University, 800E. Lancaster Ave, Villanova, Pennsylvania 19085 (United States)
H{sup -} beam was successfully extracted from a cesium seeded ion source operated using a field effect transistor inverter power supply as a radio frequency (RF) wave source. High density hydrogen plasma more than 10{sup 19} m{sup -3} was obtained using an external type antenna with RF frequency of lower than 0.5 MHz. The source was isolated by an isolation transformer and H{sup -} ion beam was extracted from a single aperture. Acceleration current and extraction current increased with the increase of extraction voltage. Addition of a small amount of cesium vapor into the source enhanced the currents.
Ando, A.; Matsuno, T.; Funaoi, T.; Tanaka, N. [School of Engineering, Tohoku University, Sendai 980-8579 (Japan); Tsumori, K.; Takeiri, Y. [National Institute for Fusion Science, Toki 509-5292 (Japan)
A multi-scale numerical model based on hydrodynamic equations with semi-kinetic treatment of electrons is used to investigate the influence of dual frequency excitation on the effective electron energy distribution function (EEDF) in a radio-frequency driven atmospheric pressure plasma. It is found that variations of power density, voltage ratio, and phase relationship provide separate control over the electron density and the mean electron energy. This is exploited to directly influence both the phase dependent and time averaged effective EEDF. This enables tailoring the EEDF for enhanced control of non-equilibrium plasma chemical kinetics at ambient pressure and temperature.
O'Neill, C.; Waskoenig, J. [Centre for Plasma Physics, School of Maths and Physics, Queen's University Belfast, Belfast BT7 1NN (United Kingdom); Gans, T. [Centre for Plasma Physics, School of Maths and Physics, Queen's University Belfast, Belfast BT7 1NN (United Kingdom); York Plasma Institute, Department of Physics, University of York, York YO10 5DD (United Kingdom)
Slow Radio-Frequency Processing of Large Oil Shale Volumes to Produce Petroleum-Like Shale Oil
Science Conference Proceedings (OSTI)
A process is proposed to convert oil shale by radio frequency heating over a period of months to years to create a product similar to natural petroleum. Electrodes would be placed in drill holes, either vertical or horizontal, and a radio frequency chosen so that the penetration depth of the radio waves is of the order of tens to hundreds of meters. A combination of excess volume production and overburden compaction drives the oil and gas from the shale into the drill holes, where it is pumped to the surface. Electrical energy for the process could be provided initially by excess regional capacity, especially off-peak power, which would generate {approx}3 x 10{sup 5} bbl/day of synthetic crude oil, depending on shale grade. The electricity cost, using conservative efficiency assumptions, is $4.70 to $6.30/bbl, depending on grade and heating rate. At steady state, co-produced gas can generate more than half the electric power needed for the process, with the fraction depending on oil shale grade. This would increase production to 7.3 x 10{sup 5} bbl/day for 104 l/Mg shale and 1.6 x 10{sup 6} bbl/day for 146 l/Mg shale using a combination of off-peak power and power from co-produced gas.
Burnham, A K
Determining an accurate position for a submm galaxy (SMG) is the crucial step that enables us to move from the basic properties of an SMG sample - source counts and 2-D clustering - to an assessment of their detailed, multi-wavelength properties, their contribution to the history of cosmic star formation and their links with present-day galaxy populations. In this paper, we identify robust radio and/or IR counterparts, and hence accurate positions, for over two thirds of the SCUBA HAlf-Degree Extragalactic Survey (SHADES) Source Catalogue, presenting optical, 24-um and radio images of each SMG. Observed trends in identification rate have given no strong rationale for pruning the sample. Uncertainties in submm position are found to be consistent with theoretical expectations, with no evidence for significant additional sources of error. Employing the submm/radio redshift indicator, via a parameterisation appropriate for radio-identified SMGs with spectroscopic redshifts, yields a median redshift of 2.8 for the radio-identified subset of SHADES, somewhat higher than the median spectroscopic redshift. We present a diagnostic colour-colour plot, exploiting Spitzer photometry, in which we identify regions commensurate with SMGs at very high redshift. Finally, we find that significantly more SMGs have multiple robust counterparts than would be expected by chance, indicative of physical associations. These multiple systems are most common amongst the brightest SMGs and are typically separated by 2-6", or 15-50/(sin i) kpc at z ~ 2, consistent with early bursts seen in merger simulations.
R. J. Ivison; T. R. Greve; J. S. Dunlop; J. A. Peacock; E. Egami; Ian Smail; E. Ibar; E. van Kampen; I. Aretxaga; T. Babbedge; A. D. Biggs; A. W. Blain; S. C. Chapman; D. L. Clements; K. Coppin; D. Farrah; M. Halpern; D. H. Hughes; M. J. Jarvis; T. Jenness; J. R. Jones; A. M. J. Mortier; S. Oliver; C. Papovich; P. G. Perez-Gonzalez; A. Pope; S. Rawlings; G. H. Rieke; M. Rowan-Robinson; R. S. Savage; D. Scott; M. Seigar; S. Serjeant; C. Simpson; J. A. Stevens; M. Vaccari; J. Wagg; C. J. Willott
Radio frequency dc-dc converters : device characterization, topology evaluation, and design
High frequency power conversion is attractive for the opportunities it affords for improved performance. Dc-dc converters operating at high frequencies use smaller-valued energy storage elements, which tend to be physically ...
Leitermann, Olivia
Radio-frequency measurements of UNiX compounds (X= Al, Ga, Ge) in high magnetic fields
We performed radio-frequency (RF) skin-depth measurements of antiferromagnetic UNiX compounds (X=Al, Ga, Ge) in magnetic fields up to 60 T and at temperatures between 1.4 to {approx}60 K. Magnetic fields are applied along different crystallographic directions and RF penetration-depth was measured using a tunnel-diode oscillator (TDO) circuit. The sample is coupled to the inductive element of a TDO resonant tank circuit, and the shift in the resonant frequency {Delta}f of the circuit is measured. The UNiX compounds exhibit field-induced magnetic transitions at low temperatures, and those transitions are accompanied by a drastic change in {Delta}f. The results of our skin-depth measurements were compared with previously published B-T phase diagrams for these three compounds.
Mielke, Charles H [Los Alamos National Laboratory; Mcdonald, David R [Los Alamos National Laboratory; Zapf, Vivien [Los Alamos National Laboratory; Altarawneh, Moaz M [Los Alamos National Laboratory; Lacerda, Alex H [Los Alamos National Laboratory; Adak, Sourav [Los Alamos National Laboratory; Karunakar, Kothapalli [Los Alamos National Laboratory; Nakotte, Heinrich [Los Alamos National Laboratory; Chang, S [NIST; Alsmadi, A M [HASHEMITE UNIV; Alyones, S [HASHEMIT UNIV
Communication and reconnaissance systems are requiring increasing flexibility concerning functionality and efficiency for multiband and broadband frequency applications. Circuit-based reconfiguration mechanisms continue to promote radio frequency (RF) application flexibility; however, increasing limitations have resulted in hindering performance. Therefore, the implementation of a "wireless" reconfiguration mechanism provides the required agility and amicability for microwave circuits and antennas without local overhead. The wireless reconfiguration mechanism in this thesis integrates dynamic, fluidic-based material systems to achieve electromagnetic agility and reduce the need for "wired" reconfiguration technologies. The dynamic material system component has become known as electromagnetically functionalized colloidal dispersions (EFCDs). In a microfluidic reconfiguration system, they provide electromagnetic agility by altering the colloidal volume fraction of EFCDs - their name highlights the special considerations we give to material systems in applied electromagnetics towards lowering loss and reducing system complexity. Utilizing EFCDs at the RF device-level produced the first circuit-type integration of this reconfiguration system; this is identified as the coaxial stub microfluidic impedance transformer (COSMIX). The COSMIX is a small hollowed segment of transmission line with results showing a full reactive loop (capacitive to inductive tuning) around the Smith chart over a 1.2 GHz bandwidth. A second microfluidic application demonstrates a novel antenna reconfiguration mechanism for a 3 GHz microstrip patch antenna. Results showed a 300 MHz downward frequency shift by dielectric colloidal dispersions. Magnetic material produced a 40 MHz frequency shift. The final application demonstrates the dynamically altering microfluidic system for a 3 GHz 1x2 array of linearly polarized microstrip patch antennas. The parallel microfluidic capillaries were imbedded in polydimethylsiloxane (PDMS). Both E- and H-plane designs showed a 250 MHz frequency shift by dielectric colloidal dispersions. Results showed a strong correlation between decreasing electrical length of the elements and an increase of the volume fraction, causing frequency to decrease and mutual coupling to increase. Measured, modeled, and analytical results for impedance, voltage standing wave ratio (VSWR), and radiation behavior (where applicable) are provided.
Goldberger, Sean A.
The global village in which we live enables increased trade and commerce across regions but also brings a complicated new set of challenges such as terrorist activity, human and drug smuggling and theft in foreign or ...
Schlesinger, Adam Ian
Approved for public release; distribution is unlimitedTHIS PAGE INTENTIONALLY LEFT BLANKREPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-
Barry A. Craft; J. D. Fulp
Analyzing the use of radio frequency identification (RFID) on the container industry
After the terrorist attacks of 9/11 US realized the importance of building and maintaining a secure environment that would protect US borders. The significance of having a secure supply chain in the US is apparent, since ...
Panagopoulos, Nikolaos-Stavros
The impact of radio frequency identification on the Sarbanes-Oxley Act of 2002
In the early years of the 21st century, a number of corporate accounting scandals forced the government to hastily adopt regulations aimed at protecting investors and restoring confidence in the financial markets. Among ...
Schannon, David R. (David Reed)
Lossless multi-way power combining and outphasing for radio frequency power amplifiers
For applications requiring the use of power amplifiers (PAs) operating at high frequencies and power levels, it is often preferable to construct multiple low power PAs and combine their output powers to form a high-power ...
Jurkov, Alexander S
The magnetic field along the jets of NGC 4258 as deduced from high frequency radio observations
We present 2.4" resolution, high sensitivity radio continuum observations of the nearby spiral galaxy NGC 4258 in total intensity and linear polarization obtained with the Very Large Array at 3.6 cm (8.44 GHz). The radio emission along the northern jet and the center of the galaxy is polarized and allows investigation of the magnetic field. Assuming energy-equipartition between the magnetic field and the relativistic particles and distinguishing between (1) a relativistic electron-proton jet and (2) a relativistic electron-positron jet, we obtain average magnetic field strengths of about (1) 310\\muG and (2) 90\\muG. The rotation measure is determined to range from -400 to -800 rad/m^2 in the northern jet. Correcting the observed E-vectors of polarized intensity for Faraday rotation, the magnetic field along the jet turns out to be orientated mainly along the jet axis. An observed tilt with respect to the jet axis may indicate also a toroidal magnetic field component or a slightly helical magnetic field around the northern jet.
M. Krause; A. L"ohr
Recent progress in the seismic interpretation of field beta Cep stars has resulted in improvements of the physics in the stellar structure and evolution models of massive stars. Further asteroseismic constraints can be obtained from studying ensembles of stars in a young open cluster, which all have similar age, distance and chemical composition. We present an observational asteroseismology study based on the discovery of numerous multi-periodic and mono-periodic B-stars in the open cluster NGC 884. We describe a thorough investigation of the pulsational properties of all B-type stars in the cluster. Overall, our detailed frequency analysis resulted in 115 detected frequencies in 65 stars. We found 36 mono-periodic, 16 bi-periodic, 10 tri-periodic, and 2 quadru-periodic stars and one star with 9 independent frequencies. We also derived the amplitudes and phases of all detected frequencies in the U, B, V and I filter, if available. We achieved unambiguous identifications of the mode degree for twelve of the de...
Saesen, S; Aerts, C; Miglio, A; Carrier, F
It has been proposed that cosmic ray events could have a causal relationship with cloud formation rates. Given the weak constraints on the role that cloud formation plays in climate forcing it is essential to understand the role such a relationship could have in shaping the Earth's climate. This issue has been previously investigated in the context of the long-term effect of cosmic ray events on climate. However, in order to establish whether or not such a relationship exists, measurements of short-timescale solar events, individual cosmic ray events, and spatially correlated cloud parameters could be of great significance. Here we propose such a comparison using observations from a pair of radio telescopes arrays, the Long Wavelength Array (LWA) and the Eight-meter-wavelength Transient Array (ETA). These low-frequency radio arrays have a unique ability to simultaneously conduct solar, ionospheric and cosmic rays observations and are thus ideal for such a comparison. We will outline plans for a comparison usi...
Magee, Nathan
Science Conference Proceedings (OSTI)
Space and phase resolved optical emission spectroscopic measurements reveal that in certain parameter regimes, inductively coupled radio-frequency driven plasmas exhibit three distinct operation modes. At low powers, the plasma operates as an alpha-mode capacitively coupled plasma driven through the dynamics of the plasma boundary sheath potential in front of the antenna. At high powers, the plasma operates in inductive mode sustained through induced electric fields due to the time varying currents and associated magnetic fields from the antenna. At intermediate powers, close to the often observed capacitive to inductive (E-H) transition regime, energetic electron avalanches are identified to play a significant role in plasma sustainment, similar to gamma-mode capacitively coupled plasmas. These energetic electrons traverse the whole plasma gap, potentially influencing plasma surface interactions as exploited in technological applications.
Zaka-ul-Islam, M.; Niemi, K. [Centre for Plasma Physics, School of Mathematics and Physics, Queen's University Belfast, University Road, Belfast BT7 1NN, Northern Ireland (United Kingdom); Gans, T.; O'Connell, D. [Centre for Plasma Physics, School of Mathematics and Physics, Queen's University Belfast, University Road, Belfast BT7 1NN, Northern Ireland (United Kingdom); York Plasma Institute, Department of Physics, University of York, Innovation Way, Heslington York YO10 5DQ (United Kingdom)
An operational radio frequency discharge-driven supersonic flow system, which utilizes an inductively and capacitively coupled plasma (ICCP) tube to produce high enthalpy source gas, is described. The ICCP coupled to a properly designed nozzle represents a potential electric propulsion device. The high gas temperatures achieved in the plasma discharge (> 5000 K) and the electrodeless nature of the tube's operation offers potentially high thruster performance coupled and long operational lifetime. A preliminary characterization of the current system was established using emission and probe-based measurements. A nominal peak specific impulse of 155 s was estimated for operation with argon. The calculated thrust based upon the peak velocity and mass flow through the device is 1.1 N. 14 refs., 10 figs.
Wantuck, P.J.; Hull, D.E.
Reduced leakage in epitaxial BiFeO{sub 3} films following oxygen radio frequency plasma treatment
Epitaxial BiFeO{sub 3} (BFO) films were deposited using pulsed laser deposition method. The prepared films were characterized using x-ray diffraction, x-ray reflectivity, ferroelectric loop tracer, and leakage current measurements before and after oxygen plasma treatment. The leakage current of the films, a crucial parameter in device applications, is observed to be reduced by two orders of magnitude with oxygen plasma treatment at room temperature. P-E hysteresis loops were observed in oxygen plasma treated BFO films. The observed results indicate the usefulness of oxygen radio frequency plasma treatment (RF 13.56 MHz), which is an effective and low temperature processing technique, in such lossy ferroelectric thin films.
Kothari, Deepti [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India) [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India); UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452 017 (India); Upadhyay, Sanjay K.; Raghavendra Reddy, V. [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452 017 (India)] [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452 017 (India); Jariwala, C.; Raole, P. M. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)] [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)
This paper will examine the implementation of scene-change detection and radio frequency technology within a Dual Containment/Surveillance (C/S) System. Additionally, this paper will examine the human performance factors in the operation of these systems. Currently, Westinghouse Savannah River Company utilizes the Continuous Item Monitoring and Surveillance System (CIMS) in the performance of Dual C/S to monitor special nuclear materials within International Atomic Energy Agency (IAEA) Safeguards and Domestic Safeguards. CIMS is comprised of the Material Monitoring System (MMS) (R), a multi-media electronic surveillance system developed by Sandia National Laboratory which incorporates the use of active seals commonly called Radio Frequency Tamper Indicating Devices (RFTIDs), NT Vision (R) as developed by Los Alamos National Laboratory, a Microsoft Windows NT (R) based operating system providing for domestic scene-change detection and the Digital Multi-Camera Optical Surveillance System (DMOS) (R) which provides scene-change detection for IAEA. Although this paper will focus on the implementation of Dual C/S utilizing the Continuous Item Monitoring and Surveillance System, the necessity for a thorough review of Safeguards and Security requirements with organizations and personnel having minimal to no prior MPC&A training will also be covered. Successful Dual C/S implementation plans must consider not only system design and failure modes, but must also be accompanied with the appropriate ''mind shift'' within operations and technical personnel. This is required to ensure completion of both physical and electronic activities, and system design changes are performed conscientiously and with full awareness of MPC&A requirements.
CMOS injection locked oscillators for quadrature generation at radio-frequency
Science Conference Proceedings (OSTI)
The design of quadrature local oscillators for CMOS wireless transceivers is still one of the most challenging issues. This paper focuses the advantages of injection locking techniques to achieve high-performance quadrature generators. A synchronizing ... Keywords: CMOS RF integrated circuits, Frequency dividers, Injection locking, Phase noise, Quadrature local oscillators, VCO
Andrea Mazzanti; Francesco Svelto
Method and apparatus for powering an electrodeless lamp with reduced radio frequency interference
An electrodeless lamp waveguide structure includes tuned absorbers for spurious RF signals. A lamp waveguide with an integral frequency selective attenuation includes resonant absorbers positioned within the waveguide to absorb spurious out-of-band RF energy. The absorbers have a negligible effect on energy at the selected frequency used to excite plasma in the lamp. In a first embodiment, one or more thin slabs of lossy magnetic material are affixed to the sidewalls of the waveguide at approximately one quarter wavelength of the spurious signal from an end wall of the waveguide. The positioning of the lossy material optimizes absorption of power from the spurious signal. In a second embodiment, one or more thin slabs of lossy magnetic material are used in conjunction with band rejection waveguide filter elements. In a third embodiment, one or more microstrip filter elements are tuned to the frequency of the spurious signal and positioned within the waveguide to couple and absorb the spurious signal's energy. All three embodiments absorb negligible energy at the selected frequency and so do not significantly diminish the energy efficiency of the lamp.
Simpson, James E. (Gaithersburg, MD)
Method and apparatus for powering an electrodeless lamp with reduced radio frequency interference
An electrodeless lamp waveguide structure includes tuned absorbers for spurious RF signals. A lamp waveguide with an integral frequency selective attenuation includes resonant absorbers positioned within the waveguide to absorb spurious out-of-band RF energy. The absorbers have a negligible effect on energy at the selected frequency used to excite plasma in the lamp. In a first embodiment, one or more thin slabs of lossy magnetic material are affixed to the sidewalls of the waveguide at approximately one quarter wavelength of the spurious signal from an end wall of the waveguide. The positioning of the lossy material optimizes absorption of power from the spurious signal. In a second embodiment, one or more thin slabs of lossy magnetic material are used in conjunction with band rejection waveguide filter elements. In a third embodiment, one or more microstrip filter elements are tuned to the frequency of the spurious signal and positioned within the waveguide to couple and absorb the spurious signal's energy. All three embodiments absorb negligible energy at the selected frequency and so do not significantly diminish the energy efficiency of the lamp. 18 figs.
Simpson, J.E.
The PARMTEQ code is used for generating the complete cell design of a radio-frequency quadrupole linear accelerator and for multiparticle simulation of the beam dynamics. We present a review of the code, with an emphasis on the physics used to describe the particle motion and the cell generation. 9 refs., 1 fig.
Crandall, K.R.; Wangler, T.P.
Dust removal in radio-frequency plasmas by a traveling potential modulation
Science Conference Proceedings (OSTI)
The dust contamination in plasma deposition processes plays a crucial role in the quality and the yield of the products. To improve the quality and the yield of plasma processing, a favorable way is to remove the dust particles actively from the plasma reactors.Our recent experiments in the striped electrode device show that a traveling plasma modulation allows for a systematic particle removal independent of the reactor size. Besides the rf powered electrode, the striped electrode device includes a segmented electrode that consists of 100 electrically insulated narrow stripes. A traveling potential profile is produced by the modulation of the voltage signals applied on the stripes. The dust particles are trapped in the potential wells and transported with the traveling of the potential profile.The particle-in-cell (PIC) simulation on the potential above the segmented electrode indicates that the traveling potential profile can be realized either by applying low-frequency (0.1-10 Hz) voltage signals with a fixed phase shift between adjacent stripes or high-frequency (10 kHz a circumflex AS 100 MHz) signals with the amplitudes modulated by a low-frequency envelope. The transportation of the dust particles is simulated with a two-dimensional molecular dynamics (MD) code with the potential profile obtained from the PIC simulation. The MD results reproduce the experimental observations successfully.This technology allows for an active removal of the contaminating particles in processing plasmas and it is independent of the reactor size. The removal velocity is controllable by adjusting the parameters for the modulation.
Li Yangfang; Jiang Ke; Thomas, Hubertus M.; Morfill, Gregor E. [Max-Planck-Institute for Extraterrestrial Physics, 85748 Garching (Germany)
Radio frequency plasma heating in large tokamak systems near the lower hybrid resonance
The frequency range, power, efficiency, and pulse length of a high power rf system are discussed as they might be applied to the TFTR Tokamak facility as well as on a full scale reactor. Comparisons are made of the size, power output, and costs to obtain microwave power sufficient to satisfy the physics requirements. A new microwave feed concept is discussed which will improve the coupling of the microwave energy into the plasma. The unique advantages of waveguide feed systems is apparent when one considers the practical problems associated with coupling supplementary heating energy into a reactor. (auth)
Deitz, A.; Hooke, W.M.
Science Conference Proceedings (OSTI)
The paper contains an overview of unique identification issues and of the various radio frequency identification techniques that are available now or will become available in the short term. The paper also compares RFID with traditional ID technologies. ... Keywords: Automatic identification, Data transfer, Identifier-based operations, Supply-chain
Elisabeth Ilie-Zudor; Zsolt Kem�ny; Fred van Blommestein; L�szl� Monostori; Andr� van der Meulen
Safe operation of superconducting radio frequency (SRF) cavities require design consideration of a sudden catastrophic loss of vacuum (SCLV) adjacent with liquid helium (LHe) vessels and subsequent dangers. An experiment is discussed to test the longitudinal effects of SCLV along the beam line of a string of scaled SRF cavities. Each scaled cavity includes one segment of beam tube within a LHe vessel containing 2 K saturated LHe, and a riser pipe connecting the LHe vessel to a common gas header. At the beam tube inlet is a fast acting solenoid valve to simulate SCLV and a high/low range orifice plate flow-meter to measure air influx to the cavity. The gas header exit also has an orifice plate flow-meter to measure helium venting the system at the relief pressure of 0.4 MPa. Each cavity is instrumented with Validyne pressure transducers and Cernox thermometers. The purpose of this experiment is to quantify the time required to spoil the beam vacuum and the effects of transient heat and mass transfer on the helium system. Heat transfer data is expected to reveal a longitudinal effect due to the geometry of the experiment. Details of the experimental design criteria and objectives are presented.
Dalesandro, A.; Theilacker, J.; /Fermilab; Van Sciver, S.W.; /Natl. High Mag. Field Lab.
Radio-frequency integrated-circuit design for CMOS single-chip UWB systems
Low cost, a high-integrated capability, and low-power consumption are the basic requirements for ultra wide band (UWB) system design in order for the system to be adopted in various commercial electronic devices in the near future. Thus, the highly integrated transceiver is trended to be manufactured by companies using the latest silicon based complimentary metal-oxide-silicon (CMOS) processes. In this dissertation, several new structural designs are proposed, which provide solutions for some crucial RF blocks in CMOS for UWB for commercial applications. In this dissertation, there is a discussion of the development, as well as an illustration, of a fully-integrated ultra-broadband transmit/receive (T/R) switch which uses nMOS transistors with deep n-well in a standard 0.18-?m CMOS process. The new CMOS T/R switch exploits patterned-ground-shield on-chip inductors together with MOSFET�s parasitic capacitances in order to synthesize artificial transmission lines which result in low insertion loss over an extremely wide bandwidth. Within DC-10 GHz, 10-18 GHz, and 18-20 GHz, the developed CMOS T/R switch exhibits insertion loss of less than 0.7, 1.0 and 2.5 dB and isolation between 32-60 dB, 25-32 dB, and 25-27 dB, respectively. The measured 1-dB power compression point and input third-order intercept point reach as high as 26.2 and 41 dBm, respectively. Further, there is a discussion and demonstration of a tunable Carrier-based Time-gated UWB transmitter in this dissertation which uses a broadband multiplier, a novel fully integrated single pole single throw (SPST) switch designed by the CMOS process, where a tunable instantaneous bandwidth from 500 MHz to 4 GHz is exhibited by adjusting the width of the base band impulses in time domain. The SPST switch utilizes the synthetic transmission line concept and multiple reflections technique in order to realize a flat insertion loss less than 1.5 dB from 3.1 GHz to 10.6 GHz and an extremely high isolation of more than 45 dB within this frequency range. A fully integrated complementary LC voltage control oscillator (VCO), designed with a tunable buffer, operates from 4.6 GHz to 5.9 GHz. The measurement results demonstrate that the integrated VCO has a very low phase noise of �117 dBc/ Hz at 1 MHz offset. The fully integrated VCO achieves a very high figure of merit (FOM) of 183.5 using standard CMOS process while consuming 4 mA DC current.
Jin, Yalin
Comparison of LaBr3:Ce and NaI(Tl) Scintillators for Radio-Isotope Identification Devices
Lanthanum halide (LaBr3:Ce) scintillators offer significantly better resolution (<3 percent at 662 kilo-electron volt [keV]) relative to sodium iodide (NaI(Tl)) and have recently become commercially available in sizes large enough for the hand-held radio-isotope identification device (RIID) market. There are drawbacks to lanthanum halide detectors, however. These include internal radioactivity that contributes to spectral counts and a low-energy response that can cause detector resolution to be lower than that of NaI(Tl) below 100 keV. To study the potential of this new material for RIIDs, we performed a series of measurements comparing a 1.5?1.5 inch LaBr?3:Ce detector with an Exploranium GR 135 RIID, which contains a 1.5-2.2 inch NaI(Tl) detector. Measurements were taken for short time frames, as typifies RIID usage. Measurements included examples of naturally occurring radioactive material (NORM), typically found in cargo, and special nuclear materials. Some measurements were noncontact, involving short distances or cargo shielding scenarios. To facilitate direct comparison, spectra from the different detectors were analyzed with the same isotope identification software (ORTEC ScintiVision TM). In general, the LaBr3:Ce detector was able to find more peaks and find them faster than the NaI(Tl) detector. To the same level of significance, the LaBr3:Ce detector was usually two to three times faster. The notable exception was for 40K containing NORM where interfering internal contamination in the LaBr3:Ce detector exist. NaI(Tl) consistently outperformed LaBr3:Ce for this important isotope. LaBr3:Ce currently costs much more than NaI(Tl), though this cost-difference is expected to diminish (but not completely) with time. As is true of all detectors, LaBr3:Ce will need to be gain-stabilized for RIID applications. This could possibly be done using the internal contaminants themselves. It is the experience of the authors that peak finding software in RIIDs needs to be improved, regardless of the detector material.
Milbrath, Brian D.; Choate, Bethany J.; Fast, Jim E.; Hensley, Walter K.; Kouzes, Richard T.; Schweppe, John E.
A method and apparatus of obtaining a record of repetitive optical or other phenomena having durations in the picosecond range, comprising a circular scan electron tube to receive light pulses and convert them to electron images consisting with fast nanosecond electronic signals, a continuous wave light or other particle pulses, e.g. electron picosecond pulses, and a synchronizing mechanism arranged to synchronize the deflection of the electron image (images) in the tube (tubes) with the repetition rate of the incident pulse train. There is also provided a method and apparatus for digitization of a repetitive and random optical waveform with a bandwidth higher than 10 GHz.
Margaryan, Amur (Yerevan, AM); Gynashyan, Karlen (Yerevan, AM); Hashimoto, Osamu (Sendai, JP); Majewski, Stanislaw (Morgantown, WV); Tang, Linguang (Yorktown, VA); Marikyan, Gagik (Yerevan, AM); Marikyan, legal representative, Lia (Yerevan, AM)
A frequency scanning method for the identification of harmonic instabilities in HVDC systems
A Frequency Scanning Method is introduced in the paper to obtain a more accurate frequency characteristic for identifying harmonic instability in HVdc systems. An example of the application is used to identify the resonance frequencies in the CIGRE benchmark model. The paper shows that the Benchmark model is not tuned to the resonance frequency that it was designed for. Using the scanning method, the resonance frequency of the benchmark model may be shifted to demonstrate a simulation of core-saturation type instability.
Jiang, X.; Gole, A.M. [Univ. of Manitoba, Winnipeg, Manitoba (Canada). Dept. of Electrical and Computer Engineering
Science Conference Proceedings (OSTI)
The particle formation in low pressure radio-frequency (13.56 MHz) CH{sub 4}/N{sub 2} discharges results from the gas decomposition and from the sputtering of the powered electrode. The particle formation and behavior are strongly modified with the nitrogen amount increase in the mixture. The observation of the particles in the CH{sub 4}/N{sub 2} mixture containing 70% of N{sub 2} reveals a particular particle behavior. The particle behavior is correlated with the electrical parameters of the discharge.
Pereira, J.; Massereau-Guilbaud, V.; Geraud-Grenier, I.; Plain, A. [LASEP, Faculte des Sciences, Universite d'Orleans, Site de Bourges, rue G. Berger, BP 4043, 18028 BOURGES CEDEX (France)
Nitrogen effect on the dust presence and behavior in a radio frequency CH{sub 4}/N{sub 2} discharge
Science Conference Proceedings (OSTI)
In this paper, we have studied the effects of the nitrogen percentage on particles generated in low pressure radio frequency CH{sub 4}/N{sub 2} discharges. The particle behavior has been analyzed by laser beam extinction and scattering. The nitrogen percentage in the mixture influences the particle presence, behavior, and size in the discharge. For nitrogen percentages greater than 50%, we have evidenced a particle multigeneration and oscillations in particle clouds. These oscillations have been correlated with the discharge electrical parameters.
Pereira, Jeremy; Massereau-Guilbaud, Veronique; Geraud-Grenier, Isabelle; Plain, Andre [LASEP, Faculte des Sciences, Universite d'Orleans, Site de Bourges, rue G. Berger, BP 4043, 18028 Bourges Cedex (France)
A frequency domain model for 3 kV dc traction dc-side resonance identification
Frequency-dependent effects in railway traction power systems arise from the impedance of substation and locomotive line filters and the traction line. Harmonic noise from traction drives and substations can excite resonances and produce overcurrent or overvoltage conditions at critical points in the network. In this paper, the harmonic feeding impedances of a 3 kV DC traction system seen from the rectifier substation, locomotive drive converter and pantograph terminals are presented. Several substation and locomotive filters are considered with a frequency-dependent traction line. Resonances attributed to the substation filter, locomotive filter and traction line are separate and distinct, the line introducing poles and zeros in the audio frequency (AF) range which vary in frequency and magnitude with locomotive position.
Hill, R.J. [Univ. of Bath (United Kingdom). School of Electronic and Electrical Engineering; Fracchia, M.; Pozzobon, P.; Sciutto, G. [Univ. degli Studi di Genova (Italy). Dipt. di Ingegneria Elettrica
Science Conference Proceedings (OSTI)
In this paper, the authors the inventory control practices of a small-to-medium retailer to identify common challenges this type of organization experiences with respect to automated data capture ADC and the implementation of an enterprise wide information ... Keywords: Automatic Identification and Data Capture AIDC, Barcode, Business Process, Information Systems, Inventory Control, Radio-Frequency Identification RFID, Small-to-Medium Retailer
Dane Hamilton; Katina Michael; Samuel Fosso Wamba
energy launched by the reader. Data for the study are calculated using CST microwave studio which applies and controllers, and the software platform made up of the middleware and the enabled applications. The transponder to attract rectifiable electromagnetic energy from the interrogating field of the reader which is used
Haddadi, Hamed
Frequency Identification of a Historical Masonry Building Based on the Bayesian Inference
Science Conference Proceedings (OSTI)
The frequency of historical masonry buildings is difficult to evaluate because of the uncertain nature of the material properties, existing damages and structural configurations. A Markov Chain Monte Carlo (MCMC) method based on the Bayesian Inference ... Keywords: Piezoelectricity, surface acoustic, wave guided wave
Rongliu Gu, Bin Peng, Zhihong Cai
Reactive atomic species play a key role in emerging cold atmospheric pressure plasma applications, in particular, in plasma medicine. Absolute densities of atomic oxygen and atomic nitrogen were measured in a radio-frequency driven non-equilibrium plasma operated at atmospheric pressure using vacuum ultra-violet (VUV) absorption spectroscopy. The experiment was conducted on the DESIRS synchrotron beamline using a unique VUV Fourier-transform spectrometer. Measurements were carried out in plasmas operated in helium with air-like N{sub 2}/O{sub 2} (4:1) admixtures. A maximum in the O-atom concentration of (9.1 {+-} 0.7) Multiplication-Sign 10{sup 20} m{sup -3} was found at admixtures of 0.35 vol. %, while the N-atom concentration exhibits a maximum of (5.7 {+-} 0.4) Multiplication-Sign 10{sup 19} m{sup -3} at 0.1 vol. %.
Niemi, K.; O'Connell, D.; Gans, T. [York Plasma Institute, Department of Physics, University of York, York YO10 5DD (United Kingdom); Oliveira, N. de; Joyeux, D.; Nahon, L. [Synchrotron Soleil, l'Orme des Merisiers, St. Aubin BP 48, 91192 Gif sur Yvette Cedex (France); Booth, J. P. [Laboratoire de Physique des Plasmas-CNRS, Ecole Polytechnique, 91128 Palaiseau (France)
Science Conference Proceedings (OSTI)
A new Heusler alloy, Fe{sub 2}(Mn,Cr)Si, that is likely to have high spin polarization (P) and high damping constant ({alpha}) was proposed to obtain high magneto-resistance ratio and low spin torque noise in a magnetic read head with a current-perpendicular-to-plane (CPP) giant magneto-resistance (GMR) multilayer. A very high frequency (VHF) plasma irradiation process during radio frequency (RF) sputter deposition was investigated to form the highly ordered structure of the Heusler alloy film with low thermal treatment temperature. The main results are as follows: (1) P and magnetic moment of Fe{sub 2}(Mn{sub 0.5}Cr{sub 0.5})Si with an L2{sub 1} structure were estimated at 0.99 and 2.49 {mu}{sub B}/f.u., respectively, and {alpha} was also estimated to be larger compared with the case of Co{sub 2}MnSi, according to density of states (DOS) calculations. (2) The ordering (at least B2 structure) temperature of Fe{sub 2}(Mn{sub 0.6}Cr{sub 0.4})Si film decreased from 500 to 300 deg. C by using the VHF plasma irradiation process with optimized condition. (3) The surface roughness of Fe{sub 2}(Mn{sub 0.6}Cr{sub 0.4})Si film also reduced from 1.7 to 0.5 nm by using the VHF plasma irradiation process. It is found that the Fe{sub 2}(Mn,Cr)Si Heusler alloy and the VHF plasma irradiation process with optimized condition seems to be applicable for fabrication of high-performance magnetic read head with CPP-GMR device.
Yoshimura, S.; Kobayashi, H.; Egawa, G.; Saito, H. [Center for Geo-environmental Science, Graduate School of Engineering and Resource Science, Akita University, Akita, 010-8502 (Japan); Ishida, S. [Department of Physics, Graduate School of Science and Engineering, Kagoshima University, Kagoshima, 890-8580 (Japan)
Predictive protocol for the scalable identification of RFID tags through collaborative readers
Science Conference Proceedings (OSTI)
Radio frequency identification (RFID) is a technology aimed at efficiently identifying products that has greatly influenced the manufacturing businesses in recent years. Although the RFID technology has been widely accepted by the manufacturing and retailing ... Keywords: Privacy, RFID, Scalable collaboration, Secure information sharing, Trajectory analysis
Rolando Trujillo-Rasua; Agusti Solanas; Pablo A. P�Rez-Mart�Nez; Josep Domingo-Ferrer
Are Cluster Radio Relics Revived Fossil Radio Cocoons?
A new model for the, so called, `cluster radio relics' is presented (Ensslin & Gopal-Krishna 2000). Fossil radio cocoons, resulting from the former activity of radio galaxies, should contain a low energy relativistic electron population and magnetic fields. Electrons with an age of even up to 2 Gyr can be re-accelerated adiabatically to radio emitting energies, if the fossil radio plasma gets compressed in an environmental shock wave. Such a wave can be caused by a merging event of galaxy clusters, or by the accretion onto galaxy clusters. An implication of this model is the existence of a population of diffuse, ultra-steep spectrum, very low-frequency radio sources located inside and possibly outside of clusters of galaxies, tracing the revival of aged fossil radio plasma by the shock waves associated with large-scale structure formation.
Torsten A. Ensslin; Gopal-Krishna
Collaborative spectrum sensing in cognitive radio networks.
??The radio frequency (RF) spectrum is a scarce natural resource, currently regulated by government agencies. With the explosive emergence of wireless applications, the demands for� (more)
Sun, Hongjian
: analysis time, power and hardware usage all scale linearly with , the number of output frequency bins cochlea designs with sharper rolloff slopes and lower group delay than prior all-pole versions. Index with position: The membrane gradually becomes wider and less stiff, and resonates at lower frequencies. Thus
Sarpeshkar, Rahul
Science Conference Proceedings (OSTI)
We report a method to fabricate high quality Bi{sub 2}Se{sub 3} thin films using molecular beam epitaxy with a radio frequency cracker cell as an atomic selenium source. With Se-to-Bi ratios close to exact stoichiometry, optimal layer-by-layer growth of high quality Bi{sub 2}Se{sub 3} thin films with smooth surfaces has been achieved on CaF{sub 2}(111) substrates and Si(111) substrates with a thin epitaxial CaF{sub 2} buffer layer (CaF{sub 2}/Si). Transport measurements show a characteristic weak-antilocalization magnetoresistance in all the films, with the emergence of a weak-localization contribution in the ultrathin film limit. Quantum oscillations, attributed to the topological surface states have been observed, including in films grown on CaF{sub 2}/Si.
Zhang Li; Dolev, Merav [Department of Applied Physics, Stanford University, Stanford, California 94305 (United States); Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305 (United States); Hammond, Robert [Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305 (United States); Liu Min [Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305 (United States); Department of Physics, Stanford University, Stanford, California 94305 (United States); Palevski, Alexander [School of Physics and Astronomy, Tel Aviv University, 69978 Tel Aviv (Israel); Kapitulnik, Aharon [Department of Applied Physics, Stanford University, Stanford, California 94305 (United States); Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305 (United States); Department of Physics, Stanford University, Stanford, California 94305 (United States)
This thesis reviews the current logistics processes and issues for container shipments in the supply chain. In particular, the problems associated with container shipments from China to the US, via the Hong Kong Port, ...
Han, Taehee
Identification of information is one key to the development of intelligent decision systems of the future. Frequency agnostic automatic identification is only one step in the physical world to make physical objects identify ...
A commercially-available titanium-sapphire laser system has recently been installed at the Fermilab A0 photoinjector laboratory in support of photoemission and electron beam diagnostics studies. The laser system is synchronized to both the 1.3-GHz master oscillator and a 1-Hz signal use to trigger the radiofrequency system and instrumentation acquisition. The synchronization scheme and performance are detailed. Long-term temporal and intensity drifts are identified and actively suppressed to within 1 ps and 1.5%, respectively. Measurement and optimization of the laser's temporal profile are accomplished using frequency-resolved optical gating.
Maxwell, Timothy; Ruan, Jinhao; Piot, Philippe; Lumpkin, Alex
Chinook salmon in the Snake River basin were listed as threatened under the Endangered Species Act in 1992 (NMFS 1992). The Secesh River represents the only stream in the Snake River basin where natural origin (wild) salmon escapement monitoring occurs at the population level, absent a supplementation program. As such the Secesh River has been identified as a long term salmon escapement and productivity monitoring site by the Nez Perce Tribe Department of Fisheries Resources Management. Salmon managers will use this data for effective population management and evaluation of the effect of conservation actions on a natural origin salmon population. The Secesh River also acts as a reference stream for supplementation program comparison. Dual frequency identification sonar (DIDSON) was used to determine adult spring and summer Chinook salmon escapement in the Secesh River in 2008. DIDSON technology was selected because it provided a non-invasive method for escapement monitoring that avoided listed species trapping and handling incidental mortality, and fish impedance related concerns. The DIDSON monitoring site was operated continuously from June 13 to September 14. The first salmon passage was observed on July 3. DIDSON site total estimated salmon escapement, natural and hatchery fish, was 888 fish {+-} 65 fish (95% confidence interval). Coefficient of variation associated with the escapement estimate was 3.7%. The DIDSON unit was operational 98.1% of the salmon migration period. Adult salmon migration timing in the Secesh River occurred over 74 days from July 3 to September 14, with 5,262 total fish passages observed. The spawning migration had 10%, median, and 90% passage dates of July 8, July 16, and August 12, respectively. The maximum number of net upstream migrating salmon was above the DIDSON monitoring site on August 27. Validation monitoring of DIDSON target counts with underwater optical cameras occurred for species identification. A total of 860 optical camera identified salmon passage observations were identical to DIDSON target counts. However, optical cameras identified eight jack salmon (3 upstream, 5 downstream) less than 55 cm in length that DIDSON did not count as salmon because of the length criteria employed ({ge} 55 cm). Precision of the DIDSON technology was evaluated by comparing estimated net upstream salmon escapement and associated 95% confidence intervals between two DIDSON sonar units operated over a five day period. The DIDSON 1 salmon escapement was 145.7 fish ({+-} 2.3), and the DIDSON 2 escapement estimate was 150.5 fish ({+-} 5). The overlap in the 95% confidence intervals suggested that the two escapement estimates were not significantly different from each other. Known length salmon carcass trials were conducted in 2008 to examine the accuracy of manually measured lengths, obtained using DIDSON software, on high frequency files at a 5 m window length. Linear regression demonstrated a highly significant relationship between known lengths and manually measured salmon carcass lengths (p < 0.0001). A positive bias in manual length measurement of 6.8% to 8% existed among the two observers in the analysis. Total Secesh River salmon escapement (natural origin and hatchery) in 2008 was 912 fish. Natural origin salmon escapement in the entire Secesh River drainage was 847 fish. The estimated natural origin spawner abundance was 836 fish. Salmon spawner abundance in 2008 increased by three fold compared to 2007 abundance levels. The 10 year geometric mean natural origin spawner abundance was 538 salmon and was below the recommended viable population threshold level established by the ICTRT (2007). One additional Snake River basin salmon population was assessed for comparison of natural origin salmon spawner abundance. The Johnson Creek/EFSF Salmon River population had a 10 year geometric mean natural origin spawner abundance of 254 salmon. Salmon spawner abundance levels in both streams were below viable population thresholds. DIDSON technology has been used in the Secesh River to determine salmo
Kucera, Paul A. [Nez Perce Tribe Department of Fisheries Resources Management
The environments of radio-loud quasars
We have obtained multi-colour imaging of a representative, statistically complete sample of low-frequency selected (S_408MHz > 0.95Jy) radio loud quasars at intermediate (0.6 environmental richness, based upon single-band observations are inadequate at these redshifts for a variety of reasons. Environmental richness seems correlated with the size and morphology of the radio source, as expected if the energy density in the radio lobes is approximately the equipartition value and the lobes are in pressure equilbrium with a surrounding intragroup/cluster medium. Selecting on radio size therefore efficiently selects dense galactic sytems at these redshifts.
J. M. Barr; M. N. Bremer; J. C. Baker
NLE Websites -- All DOE Office Websites (Extended Search)
. . Coherent radio Cherenkov radiation detectors: Revised February 2013 by S.R. Klein (LBNL/UC Berkeley) 100 10 10 -4 10 -3 10 -5 1.0 0.1 0.01 E 2 I(E ν ) [GeV m -2 s -1 sr -1 ] E ν [GeV] ν NuMoon 10 9 10 10 10 11 10 12 10 13 10 14 10 15 ATCA (no SSR) ATCA (SSR incl.) RICE ANITA Central GZK ν flux predictions Central GZK ν flux predictions Figure 1: Representative ν flux limits from radio-detection experiments, illustrating the energy ranges for different techniques. Shown are limits from the Rice, ANITA, NuMoon and Lunaska (ATCA) collaborations. NuMoon and Lunaska are low and high frequency lunar scans respectively, showing the strengths of the two different frequency bands. The two limits for ATCA are for different models of the lunar regolith; their separation is a measure of the resultant uncertainty. Also shown, for comparison is the mid-range of flux predictions
Light modulated switches and radio frequency emitters
The disclosure relates to a light modulated electron beam driven radiofrequency emitter. Pulses of light impinge on a photoemissive device which generates an electron beam having the pulse characteristics of the light. The electron beam is accelerated through a radiofrequency resonator which produces radiofrequency emission in accordance with the electron, hence, the light pulses.
Wilson, Mahlon T. (Los Alamos, NM); Tallerico, Paul J. (Los Alamos, NM)
Dielectric supported radio-frequency cavities
A device which improves the electrical and thermomechanical performance of an RF cavity, for example, in a disk-loaded accelerating structure. A washer made of polycrystalline diamond is brazed in the middle to a copper disk washer and at the outer edge to the plane wave transformer tank wall, thus dissipating heat from the copper disk to the outer tank wall while at the same time providing strong mechanical support to the metal disk. The washer structure eliminates the longitudinal connecting rods and cooling channels used in the currently available cavities, and as a result minimizes problems such as shunt impedance degradation and field distortion in the plane wave transformer, and mechanical deflection and uneven cooling of the disk assembly.
Yu, David U. L. (Rancho Palos Verdes, CA); Lee, Terry G. (Cupertino, CA)
Overview of Personal Radio Frequency Communication Technologies
Science Conference Proceedings (OSTI)
Personal wireless communication devices seem to be everywhere. Cell phones, Blackberries, Wi-Fi Internet connections and many other similar devices are in constant use, often simultaneously by a single person. As the proliferation of wireless products expands, their ubiquity raises questions concerning their effects on each other and the people who use them. The effects of one communications device on another one nearby fall under the category of electromagnetic compatibility. Compatibility issues arise ...
Radio Frequency Lamination for Photovoltaic Panels
Science Conference Proceedings (OSTI)
Strategies for overcoming residual stress in interlayers surrounding embedded PV cells will be discussed. Working prototypes of RF laminated solar panels will�...
Radio-Frequency Electronics Group Homepage
Science Conference Proceedings (OSTI)
... High Speed Electronics�This project supports the microwave, telecommunications ... this project we measure the fundamental electrical ...
Radio frequency digital to analog converter
Dynamic performance of high speed, high resolution digital-to-analog converters (DACs) is limited by distortion at the data switching instants. Inter-symbol interference (ISI), imperfect timing synchronization and clock ...
Luschas, Susan, 1975-
Phase manipulation for efficient radio frequency transmission
Power amplifiers (PAs) for microwave communications are generally the most power-hungry element of a transmitter. High linearity is required for modern digital communications standards, and often is achieved at the expense ...
Barton, Taylor Wallis
Auction-Based Throughput Maximization in Cognitive Radio Networks Under Interference Constraint
Science Conference Proceedings (OSTI)
Cognitive radio is an emerging technique to improve the utilization of radio frequency spectrum in wireless communication networks. That is, spectrum efficiency can be increased significantly by giving opportunistic access of the frequency bands to a ... Keywords: Auction, Channel assignment, Cognitive radio, Graph theory, Interference constraint, OSI cross layer applications
Hakan Murat Karaca, Tolga Kurt, Salih Zafer Dicle, Emin Anarim
The effect of O{sub 2} partial pressure on the mechanical properties of Al{sub 2}O{sub 3} films is studied. Using films prepared by inductively coupled plasma-assisted radio frequency magnetron sputtering, the deposition rate of Al{sub 2}O{sub 3} decreases rapidly when oxygen is added to the argon sputtering gas. The internal stresses in the films are compressive, with magnitude decreasing steeply from 1.6 GPa for films sputtered in pure argon gas to 0.5 GPa for films sputtered in argon gas at an O{sub 2} partial pressure of 0.89 Multiplication-Sign 10{sup -2} Pa. Stress increases gradually with increasing O{sub 2} partial pressure. Using a nanoindentation tester with a Berkovich indenter, film hardness was measured to be about 14 GPa for films sputtered in pure argon gas. Hardness decreases rapidly on the addition of O{sub 2} gas, but increases when the O{sub 2} partial pressure is increased. Adhesion, measured using a Vickers microhardness tester, increases with increasing O{sub 2} partial pressure. Electron probe microanalyzer measurements reveal that the argon content of films decreases with increasing O{sub 2} partial pressure, whereas the O to Al composition ratio increases from 1.15 for films sputtered in pure argon gas to 1.5 for films sputtered in argon gas at O{sub 2} partial pressures over 2.4 Multiplication-Sign 10{sup -2} Pa. X-ray diffraction measurements reveal that films sputtered in pure argon gas have an amorphous crystal structure, whereas {gamma}-Al{sub 2}O{sub 3} is produced for films sputtered in argon gas with added O{sub 2} gas. Atomic force microscopy observations reveal that the surface topography of sputtered Al{sub 2}O{sub 3} films changes from spherical to needlelike as O{sub 2} partial pressure is increased. Fracture cross sections of the films observed by scanning electron microscopy reveal that the film morphology exhibits no discernible features at all O{sub 2} partial pressures.
Fujiyama, Hirokazu; Sumomogi, Tsunetaka; Nakamura, Masayoshi [Faculty of Engineering, Fukuoka Institute of Technology, 3-30-1 Wajirohigashi, Higashi-ku, Fukuoka 811-0295 (Japan); Faculty of Engineering, Hiroshima Kokusai Gakuin University, 6-20-1 Nakano, Aki-ku, Hiroshima 739-0321 (Japan)
--In this letter, a novel linear frequency-domain compensation (FDC) of the resonant cavity light emitting diode emitting diodes (RC-LED) have been largely adopted in POF communications with on-off-keying modulation insensitivity, which are extremely suitable for optical home networking [2]. The low-cost resonant cavity light
Recanati, Catherine
Vital Alert's C1000 mine and tunnel radios use magnetic induction...
NLE Websites -- All DOE Office Websites (Extended Search)
Vital Alert's C1000 mine and tunnel radios use magnetic induction, advanced digital communications techniques and ultra-low frequency transmission to wirelessly provide...
Automatic calibration of modulated fractional-N frequency synthesizers
The focus of this research has been the development of a low power, radio frequency transmitter architecture. Specifically, a technique for in service automatic calibration of a modulated phase locked loop (PLL) frequency ...
McMahill, Dan
??The frequency assignment (FAP) consists in assigning the frequency on the radio links of a network which satisfiesthe electromagnetic interference among the links. Given the� (more)
Hu, Jun
Direct analog-to-digital conversion of multi-GHz radio frequency (RF) signals is the ultimate goal in software radio receiver design but remains a daunting challenge for any technology. This thesis examines the potential ...
Bulzacchelli, John F. (John Francis)
Underground radio technology saves miners and emergency response personnel
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Underground radio technology saves miners and emergency response Underground radio technology saves miners and emergency response personnel Underground radio technology saves miners and emergency response personnel Founded through LANL, Vital Alert Technologies, Inc. (Vital Alert) has launched a wireless, two-way real-time voice communication system that is effective through 1,000+ feet of solid rock. April 3, 2012 Vital Alert's C1000 mine and tunnel radios use magnetic induction, advanced digital communications techniques and ultra-low frequency transmission to wirelessly provide reliable 2-way voice, text, or data links through rock strata and other solid media. Vital Alert's C1000 mine and tunnel radios use magnetic induction, advanced digital communications techniques and ultra-low frequency transmission to wirelessly provide reliable 2-way voice, text, or data links through rock
U.S. Energy Information Administration (EIA) Indexed Site
September 10, 2012 September 10, 2012 Test of Energy News Radio Service This is a test audio file of the U.S. Energy Information Administration's energy news radio service to be launched on Tuesday, September 11 th with the release of EIA's monthly Short-Term Energy Outlook. EIA's radio service will provide free short broadcast stories on EIA energy data reports and analysis to radio stations nationwide. The stories will be recorded in MP3 format and can be downloaded from EIA's radio service webpage at www.eia.gov/radio. The first broadcast stories will be posted around noon Eastern Time on Sept. 11 after the release of EIA's monthly Short Term Energy Outlook forecast. These initial stories will focus on the outlook for U.S. gasoline prices, crude oil production and natural gas production.
The national livestock identification system: The importance of traceability in e-business
This paper aims to explore how Radio Frequency Identification (RFID) can be utilized on dairy farms to enhance total farm management. There is a growing worldwide trend for countries to implement whole-of-life traceability systems for livestock, and RFID is clearly the dominant technology being chosen to achieve this aim. In line with this global trend, and to meet the requirements of key trading partners (such as the EU), Australia has implemented the National Livestock Identification System (NLIS) to provide whole-of-life traceability for livestock � a system based on the use of RFID devices. As such, it is proposed that dairy farmers utilise RFID so as to not only comply with NLIS requirements, but to extend the use of RFID onto their farms so as to provide additional benefits for themselves through subsequent enhancements in farm management practices.
Adam Trevarthen
We have searched 75 unidentified radio sources selected from the NRAO VLA Sky Survey catalog for the presence of rapidly spinning pulsars and short, dispersed radio bursts. The sources are radio bright, have no identifications or optical source coincidences, are more than 5% linearly polarized, and are spatially unresolved in the catalog. If these sources are fast-spinning pulsars (e.g., sub-millisecond pulsars), previous large-scale pulsar surveys may have missed detection due to instrumental and computational limitations, eclipsing effects, or diffractive scintillation. The discovery of a sub-millisecond pulsar would significantly constrain the neutron star equation of state and would have implications for models predicting a rapid slowdown of highly recycled X-ray pulsars to millisecond periods from, e.g., accretion disk decoupling. These same sources were previously searched unsuccessfully for pulsations at 610 MHz with the Lovell Telescope at Jodrell Bank. This new search was conducted at a different epoch with a new 800 MHz backend on the NRAO 43 m Telescope at a center frequency of 1200 MHz. Our search was sensitive to sub-millisecond pulsars in highly accelerated binary systems and to short transient pulses. No periodic or transient signals were detected from any of the target sources. We conclude that diffractive scintillation, dispersive smearing, and binary acceleration are unlikely to have prevented detection of the large majority of the sources if they are pulsars, though we cannot rule out eclipsing, nulling or intermittent emission, or radio interference as possible factors for some non-detections. Other (speculative) possibilities for what these sources might include radio-emitting magnetic cataclysmic variables or older pulsars with aligned magnetic and spin axes.
Schmidt, Deborah; Crawford, Fronefield; Gilpin, Claire [Department of Physics and Astronomy, Franklin and Marshall College, P.O. Box 3003, Lancaster, PA 17604 (United States); Langston, Glen [National Radio Astronomy Observatory, P.O. Box 2, Green Bank, WV 24944 (United States)
Smart Radio Spectrum Management for Cognitive Radio
Today's wireless networks are characterized by fixed spectrum assignment policy. The limited available spectrum and the inefficiency in the spectrum usage necessitate a new communication paradigm to exploit the existing wireless spectrum opportunistically. Cognitive radio is a paradigm for wireless communication in which either a network or a wireless node changes its transmission or reception parameters to communicate efficiently avoiding interference with licensed or unlicensed users. In this work, a fuzzy logic based system for spectrum management is proposed where the radio can share unused spectrum depending on some parameters like distance, signal strength, node velocity and availability of unused spectrum. The system is simulated and is found to give satisfactory results.
Bhattacharya, Partha Pratim; Gera, Rishita; Agarwal, Anjali
IEEE Proof W eb Version IEEE TRANSACTIONS ON SMART GRID 1 Cognitive Radio Network for the Smart Grid: Experimental System Architecture, Control Algorithms, Security, and Microgrid Testbed Robert of applying the next generation wireless technology, cognitive radio network, for the smart grid
Schenato, Luca
We use frequency-dependent position shifts of flat-spectrum radio cores to estimate the kinetic power of active galactic nucleus (AGN) jets. We find a correlation between the derived jet powers and AGN narrow-line luminosity, consistent with the well-known relation for radio galaxies and steep spectrum quasars. This technique can be applied to intrinsically weak jets even at high redshift.
Shabala, S. S.; Santoso, J. S. [School of Mathematics and Physics, University of Tasmania, Private Bag 37, Hobart, TAS 7001 (Australia); Godfrey, L. E. H. [International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth, Western Australia 6845 (Australia)
Interaction Between AM Radio Broadcast Antennas and Overhead Power Lines
Science Conference Proceedings (OSTI)
Metallic structures, power lines or otherwise, can affect the operation of AM radio broadcast station antennas if the dimensions of those structures are related to the wavelength of the radio signal at the station's operating frequency. For power lines, the dimensions of interest can be either the height of the support structures themselves or the length of a loop formed by adjacent structures, the shield wires connecting them, and the return path in the earth. When resonance occurs between the power lin...
Power Quality Waveform Identification
Science Conference Proceedings (OSTI)
This report describes the desired functionality, attributes and proposed development approach of a power quality (PQ) event identification tool that is planned to be developed under the Electric Power Research Institute (EPRI) Power Quality program P1.BackgroundPQ monitors capture a wide variety of disturbance events, ranging in frequency from direct current to a few megahertz. Advances in PQ monitoring and instrumentation allow continuous measurement and ...
Applications and noise properties of high repetition rate : TiSapphire frequency combs
Femtosecond mode-locked lasers are a unique laser technology due to their broad optical bandwidth and potential for linking the optical and radio frequency domains when these lasers are configured as frequency combs. ...
Benedick, Andrew John
eRadio : empowerment through community Web radio
The eRadio project proposes to be an effective aid to increase interaction and reduce alienation among the members of dispersed communities by using a holistic approach to participatory and interactive web radio-production, ...
Gomez-Monroy, Carla, 1977-
Radio emissions from terrestrial gamma-ray flashes Joseph R. Dwyer1
. Introduction 1.1. TGF Theory Overview [2] Terrestrial gamma-ray flashes (TGFs) are bright bursts of gamma raysRadio emissions from terrestrial gamma-ray flashes Joseph R. Dwyer1 and Steven A. Cummer2 Received frequency (RF) emissions by terrestrial gamma-ray flashes (TGFs) is developed. These radio emissions, which
Cummer, Steven A.
Ion cyclotron range of frequencies heating of plasma with small impurity production
Plasma including plasma ions is magnetically confined by a magnetic field. The plasma has a defined outer surface and is intersected by resonance surfaces of respective common ion cyclotron frequency of a predetermined species of plasma ions moving in the magnetic field. A radio frequency source provides radio frequency power at a radio frequency corresponding to the ion cyclotron frequency of the predetermined species of plasma ions moving in the field at a respective said resonance surface. RF launchers coupled to the radio frequency source radiate radio frequency energy at the resonance frequency onto the respective resonance surface within the plasma from a plurality of locations located outside the plasma at such respective distances from the intersections of the respective resonance surface and the defined outer surface and at such relative phases that the resulting interference pattern provides substantially null net radio frequency energy over regions near and including substantial portions of the intersections relative to the radio frequency energy provided thereby at other portions of the respective resonance surface within the plasma.
Ohkawa, Tihiro (La Jolla, CA)
Special Presentation: Key Findings from the Barrier Immune Radio
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Special Presentation: Key Findings from the Barrier Immune Radio Special Presentation: Key Findings from the Barrier Immune Radio Communications Project Speaker(s): Francis Rubinstein Girish Ghatikar Peter Haugen Date: November 29, 2007 - 12:00pm Location: 90-3122 The Barrier Immune Radio Communications (BIRC) Project was established in January 2007 by the Demand Response Emerging Technologies Program (DRETD) to identify radio frequency technologies that could enable the widespread deployment of Demand Response strategies in buildings. Researchers from Lawrence Berkeley National Laboratory and Lawrence Livermore National Laboratory will present the key findings from this project in a one-hour presentation. Researchers found that several of the RF technologies tested at LBNL's Molecular Foundry building were able to provide sufficiently
First `Winged' and `X'-shaped Radio Source Candidates
A small number of double-lobed radio galaxies (17 from our own census of the literature) show an additional pair of low surface brightness ''wings'', thus forming an overall ''X''-shaped appearance. The origin of the wings in these radio sources is unclear. They may be the result of back-flowing plasma from the currently active radio lobes into an asymmetric medium surrounding the active nucleus, which would make these ideal systems in which to study thermal/non-thermal plasma interactions in extragalactic radio sources. Another possibility is that the wings are the aging radio lobes left over after a (rapid) realignment of the central supermassive black-hole/accretion disk system due perhaps to a merger. Generally, these models are not well tested; with the small number of known examples, previous works focused on detailed case studies of selected sources with little attempt at a systematic study of a large sample. Using the VLA-FIRST survey database, we are compiling a large sample of winged and X-shaped radio sources for such studies. As a first step toward this goal, an initial sample of 100 new candidate objects of this type are presented in this paper. The search process is described, optical identifications from available literature data, and basic radio data are presented. From the limited resolution FIRST images ({approx} 5''), we can already confidently classify a sufficient number of these objects as having the characteristic wing lengths >80% of the active lobes to more than double the number of known X-shaped radio sources. We have also included as candidates, radio sources with shorter wings (<80% wing to lobe length ratios), or simply ''winged'' sources, as it is probable that projection effects are important. Finally, among the candidates are four quasars (z=0.37 to 0.84), and several have morphologies suggestive of Fanaroff-Riley type-I (low-power) radio galaxies. While followup observations are necessary to confirm these identifications, this stresses the importance of source orientation and imaging limitations in finding these enigmatic objects.
Cheung, C.C.
A radio ranging device is described. It utilizes a super regenerative detector-oscillator in which echoes of transmitted pulses are received in proper phase to reduce noise energy at a selected range and also at multiples of the selected range.
Nieset, R.T.
Satellite Radio: Its Global Impact
Geo-Stationary High-powered Satellites · Processed and Transparent Payloads · Solar-Powered Provides A is the satellite transmit characteristics, determined by state-of art satellite power, coverage area; B is Receive WorldSpace XM Sirius MBSAT #12;8 Satellite Radio: A Confluence of Technologies Radio Radio Internet
Udgaonkar, Jayant B.
RASDR: Benchtop Demonstration of SDR for Radio Astronomy
The Society of Amateur Radio Astronomers (SARA) members present the benchtop version of RASDR, a Software Defined Radio (SDR) that is optimized for Radio Astronomy. RASDR has the potential to be a common digital receiver interface useful to many SARA members. This document describes the RASDR 0.0 , which provides digitized radio data to a backend computer through a USB 2.0 interface. A primary component of RASDR is the Lime Microsystems Femtocell chip which tunes from a 0.4-4 GHz center frequency with several selectable bandwidths from 0.75 MHz to 14 MHz. A second component is a board with a Complex Programmable Logic Device (CPLD) chip that connects to the Femtocell and provides two USB connections to the backend computer. A third component is an analog balanced mixer up conversion section. Together these three components enable RASDR to tune from 0.015 MHz thru 3.8GHz of the radio frequency (RF) spectrum. We will demonstrate and discuss capabilities of the breadboard system and SARA members will be able to operate the unit hands-on throughout the workshop.
Vacaliuc, Bogdan [ORNL; Oxley, Paul [Retired; Fields, David [ORNL; Kurtz, Dr. Stan [Universidad Nacional Autonoma de Mexico (UNAM); Leech, Marcus [Shirleys Bay Radio Astronomy Consortium
Surface plasma source with saddle antenna radio frequency plasma generator
Science Conference Proceedings (OSTI)
A prototype RF H{sup -} surface plasma source (SPS) with saddle (SA) RF antenna is developed which will provide better power efficiency for high pulsed and average current, higher brightness with longer lifetime and higher reliability. Several versions of new plasma generators with small AlN discharge chambers and different antennas and magnetic field configurations were tested in the plasma source test stand. A prototype SA SPS was installed in the Spallation Neutron Source (SNS) ion source test stand with a larger, normal-sized SNS AlN chamber that achieved unanalyzed peak currents of up to 67 mA with an apparent efficiency up to 1.6 mA/kW. Control experiments with H{sup -} beam produced by SNS SPS with internal and external antennas were conducted. A new version of the RF triggering plasma gun has been designed. A saddle antenna SPS with water cooling is fabricated for high duty factor testing.
Dudnikov, V.; Johnson, R. P. [Muons, Inc., Batavia, Illinios 60510 (United States); Murray, S.; Pennisi, T.; Piller, C.; Santana, M.; Stockli, M.; Welton, R. [ORNL, Oak Ridge, Tennessee 37831 (United States)
Compact, low power radio frequency cavity for femtosecond electron microscopy
Science Conference Proceedings (OSTI)
Reported here is the design, construction, and characterization of a small, power efficient, tunable dielectric filled cavity for the creation of femtosecond electron bunches in an existing electron microscope without the mandatory use of femtosecond lasers. A 3 GHz pillbox cavity operating in the TM{sub 110} mode was specially designed for chopping the beam of a 30 keV scanning electron microscope. The dielectric material used is ZrTiO{sub 4}, chosen for the high relative permittivity ({epsilon}{sub r}= 37 at 10 GHz) and low loss tangent (tan {delta}= 2 x 10{sup -4}). This allows the cavity radius to be reduced by a factor of six, while the power consumption is reduced by an order of magnitude compared to a vacuum pillbox cavity. These features make this cavity ideal as a module for existing electron microscopes, and an alternative to femtosecond laser systems integrated with electron microscopes.
Lassise, A.; Mutsaers, P. H. A.; Luiten, O. J. [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)
Radio frequency discharge with control of plasma potential distribution
Science Conference Proceedings (OSTI)
A RF discharge plasma generator with additional electrodes for independent control of plasma potential distribution is proposed. With positive biasing of this ring electrode relative end flanges and longitudinal magnetic field a confinement of fast electrons in the discharge will be improved for reliable triggering of pulsed RF discharge at low gas density and rate of ion generation will be enhanced. In the proposed discharge combination, the electron energy is enhanced by RF field and the fast electron confinement is improved by enhanced positive plasma potential which improves the efficiency of plasma generation significantly. This combination creates a synergetic effect with a significantly improving the plasma generation performance at low gas density. The discharge parameters can be optimized for enhance plasma generation with acceptable electrode sputtering.
Dudnikov, Vadim [Muons, Inc., Batavia, Illinois 60510 (United States); Dudnikov, A. [BINP, Novosibirsk 63090 (Russian Federation)
A bio-inspired active radio-frequency silicon cochlea
Fast wideband spectrum analysis is expensive in power and hardware resources. We show that the spectrum-analysis architecture used by the biological cochlea is extremely efficient: analysis time, power and hardware usage ...
Sarpeshkar, Rahul
Narrowband high temperature superconducting receiver for low frequency radio waves
An underground communicating device has a low-noise SQUID using high temperature superconductor components connected to detect a modulated external magnetic flux for outputting a voltage signal spectrum that is related to the varying magnetic flux. A narrow bandwidth filter may be used to select a portion of the voltage signal spectrum that is relatively free of power line noise to output a relatively low noise output signal when operating in a portion of the electromagnetic spectra where such power line noise exists. A demodulator outputs a communication signal, which may be an FM signal, indicative of a modulation on the modulated external magnetic flux.
Reagor, David W. (Los Alamos, NM)
Bootstrap currents in radio-frequency-driven tokamak equilibria
Interest in the bootstrap current arising from neoclassical transport in tokamaks has increased recently in view of certain experimental observations. In this study, the bootstrap current is calculated for a number of rf current-driven tokamaks. Two-dimensional, self-consistent, steady-state tokamak MHD equilibria are obtained by including both the transport-driven bootstrap current and the externally driven rf current. The self-consistency is acomplished by iterating between two-dimensional MHD equilibrium calculations and the current calculations (including bootstrap and rf ray-tracing). Calculations for other reactor parameters of interest are also carried out. It is found that for reactor-grade plasmas, the bootstrap current contribution to the toroidal current is, in general, important. An approxiamte scaling law for GAMMA, based on parametric survey performed, is also obtained. 16 refs., 8 figs., 1 tab.
Hsiao, Ming-Yuan; Ehst, D.A.; Evans, K. Jr.
NIST Time and Frequency Radio Stations: WWV, WWVH, and ...
Science Conference Proceedings (OSTI)
... that would later also become the home of WWV. ... They include heating coils and run year round. ... company provides power through an oil-filled, 500 ...
Radio-frequency quadrupole resonator for linear accelerator
An RFQ resonator for a linear accelerator having a reduced level of interfering modes and producing a quadrupole mode for focusing, bunching and accelerating beams of heavy charged particles, with the construction being characterized by four elongated resonating rods within a cylinder with the rods being alternately shorted and open electrically to the shell at common ends of the rods to provide an LC parallel resonant circuit when activated by a magnetic field transverse to the longitudinal axis.
Moretti, A.
Quantum dots and radio-frequency electrometry in silicon.
??This thesis describes the development and demonstration of a new technique for the fabrication of well-defined quantum dots in a bulk silicon substrate, for potential� (more)
Angus, Susan J.
NIST SP 800-98, Guidelines for Securing Radio Frequency ...
Science Conference Proceedings (OSTI)
... business risks associated with implementing RFID technology. ... GUIDELINES FOR SECURING RFID SYSTEMS ... to understand later material in the ...
Current Challenges and Physics of Superconducting Radio-Frequency...
NLE Websites -- All DOE Office Websites (Extended Search)
Recent performance advances in superconducting RF (SRF) cavities have made RF superconductivity a vital technology for accelerators which serve a variety of experimental...
19th Topical Conference on Radio Frequency Power in Plasmas ...
NLE Websites -- All DOE Office Websites (Extended Search)
Join Our Mailing List A Collaborative National Center for Fusion & Plasma Research Search form Search Search Home About Overview Learn More Visiting PPPL History...
NIST Time and Frequency Radio Stations: WWV, WWVH, and ...
Science Conference Proceedings (OSTI)
... year, depending on weather conditions and irrigation ... The air conditioning units currently in operation ... kVA, Y-connected three-phase transformer. ...
Cerenkov radio pulses from electromagnetic showers in the time domain
Science Conference Proceedings (OSTI)
The electric field of the Cerenkov radio pulse produced by a single charged particle track in a dielectric medium is derived from first principles. An algorithm is developed to obtain the pulse in the time domain for numerical calculations. The algorithm is implemented in a Monte Carlo simulation of electromagnetic showers in dense media (specifically designed for coherent radio emission applications) as might be induced by interactions of ultrahigh energy neutrinos. The coherent Cerenkov radio emission produced by such showers is obtained simultaneously both in the time and frequency domains. A consistency check performed by Fourier transforming the pulse in time and comparing it to the frequency spectrum obtained directly in the simulations yields, as expected, fully consistent results. The reversal of the time structure inside the Cerenkov cone and the signs of the corresponding pulses are addressed in detail. The results, besides testing algorithms used for reference calculations in the frequency domain, shed new light into the properties of the radio pulse in the time domain. The shape of the pulse in the time domain is directly related to the depth development of the excess charge in the shower and its width to the observation angle with respect to the Cerenkov direction. This information can be of great practical importance for interpreting actual data.
Alvarez-Muniz, Jaime; Romero-Wolf, Andres; Zas, Enrique [Depto. de Fisica de Particulas and Instituto Galego de Fisica de Altas Enerxias, Universidade de Santiago de Compostela, 15782 Santiago de Compostela (Spain); Department of Physics and Astronomy, University of Hawaii at Manoa, Honolulu, Hawaii 96822 (United States); Depto. de Fisica de Particulas and Instituto Galego de Fisica de Altas Enerxias, Universidad de Santiago de Compostela, 15782 Santiago de Compostela (Spain)
NLE Websites -- All DOE Office Websites (Extended Search)
Gene Frequency Gene Frequency Name: donna Location: N/A Country: N/A Date: N/A Question: If six fingers is a dominant human trait why do we have only five? Replies: This is simple. There are just not many genes in the human population for six fingers. Steve Sample Look in any high school biology book for what is known as Hardy-Weinberg equilibrium. These two scientists (separately) said that gene frequencies do not change much unless something in the environment selects them over other genes. In other words, unless 6 fingers somehow becomes an advantage, and five-fingered people have less of an advantage, the frequency of six fingered people in the population will not necessarily increase. This is the same reason that recessive traits don't disappear from the population. Also, six fingers is not considered attractive and they may not get as many mates. Also, more people are born with six fingers than you might imagine but just have them amputated shortly after birth.
Higher layer issues in cognitive radio network
Science Conference Proceedings (OSTI)
Cognitive radio networks are smart networks that automatically sense the channel and adjust the network parameters accordingly. Cognitive radio is an emerging technology that enables the dynamic deployment of highly adaptive radios that are built upon ... Keywords: cognitive radio network (CRN), issues, routing issues, security issues, software defined radio
Saed Alrabaee; Anjali Agarwal; Nishith Goel; Marzia Zaman; Mahmoud Khasawneh
Interplanetary Radio Transmission Through Serial Ionospheric and Material Barriers
Science Conference Proceedings (OSTI)
A usual first principle in planning radio astronomy observations from the earth is that monitoring must be carried out well above the ionospheric plasma cutoff frequency (~5 MHz). Before space probes existed, radio astronomy was almost entirely done above 6 MHz, and this value is considered a practical lower limit by most radio astronomers. Furthermore, daytime ionization (especially D-layer formation) places additional constraints on wave propagation, and waves of frequency below 10-20 MHz suffer significant attenuation. More careful calculations of wave propagation through the earth s ionosphere suggest that for certain conditions (primarily the presence of a magnetic field) there may be a transmission window well below this assumed limit. Indeed, for receiving extraterrestrial radiation below the ionospheric plasma cutoff frequency, a choice of VLF frequency appears optimal to minimize loss. The calculation, experimental validation, and conclusions are presented here. This work demonstrates the possibility of VLF transmission through the ionosphere and various subsequent material barriers. Implications include development of a new robust communications channel, communications with submerged or subterranean receivers / instruments on or offworld, and a new approach to SETI.
Fields, David [ORNL; Kennedy, Robert G [ORNL; Roy, Kenneth I [ORNL; Vacaliuc, Bogdan [ORNL
Radio Remote Sensing of the Corona and the Solar Wind
Modern radio telescopes are extremely sensitive to plasma on the line of sight from a radio source to the antenna. Plasmas in the corona and solar wind produce measurable changes in the radio wave amplitude and phase, and the phase difference between wave fields of opposite circular polarization. Such measurements can be made of radio waves from spacecraft transmitters and extragalactic radio sources, using radio telescopes and spacecraft tracking antennas. Data have been taken at frequencies from about 80 MHz to 8000 MHz. Lower frequencies probe plasma at greater heliocentric distances. Analysis of these data yields information on the plasma density, density fluctuations, and plasma flow speeds in the corona and solar wind, and on the magnetic field in the solar corona. This paper will concentrate on the information that can be obtained from measurements of Faraday rotation through the corona and inner solar wind. The magnitude of Faraday rotation is proportional to the line of sight integral of the plasma density and the line-of-sight component of the magnetic field. Faraday rotation provides an almost unique means of estimating the magnetic field in this part of space. This technique has contributed to measurement of the large scale coronal magnetic field, the properties of electromagnetic turbulence in the corona, possible detection of electrical currents in the corona, and probing of the internal structure of coronal mass ejections (CMEs). This paper concentrates on the search for small-scale coronal turbulence and remote sensing of the structure of CMEs. Future investigations with the Expanded Very Large Array (EVLA) or Murchison Widefield Array (MWA) could provide unique observational input on the astrophysics of CMEs.
Steven R. Spangler; Catherine A. Whiting
Science Conference Proceedings (OSTI)
Type II solar radio bursts are the primary radio emissions generated by shocks and they are linked with impending space weather events at Earth. We simulate type II bursts by combining elaborate three-dimensional MHD simulations of realistic coronal mass ejections (CMEs) at the Sun with an analytic kinetic radiation theory developed recently. The modeling includes initialization with solar magnetic and active region fields reconstructed from magnetograms of the Sun, a flux rope of the initial CME dimensioned with STEREO spacecraft observations, and a solar wind driven with averaged empirical data. We demonstrate impressive accuracy in time, frequency, and intensity for the CME and type II burst observed on 2011 February 15. This implies real understanding of the physical processes involved regarding the radio emission excitation by shocks and supports the near-term development of a capability to predict and track these events for space weather prediction.
Schmidt, J. M.; Cairns, Iver H. [School of Physics, University of Sydney, NSW 2006 (Australia); Hillan, D. S., E-mail: email@example.com [CSIRO Earth Science and Resource Engineering, North Ryde, NSW 2113 (Australia)
Science Conference Proceedings (OSTI)
Recent discoveries of dispersed, non-periodic impulsive radio signals with single-dish radio telescopes have sparked significant interest in exploring the relatively uncharted space of fast transient radio signals. Here we describe V-FASTR, an experiment to perform a blind search for fast transient radio signals using the Very Long Baseline Array (VLBA). The experiment runs entirely in a commensal mode, alongside normal VLBA observations and operations. It is made possible by the features and flexibility of the DiFX software correlator that is used to process VLBA data. Using the VLBA for this type of experiment offers significant advantages over single-dish experiments, including a larger field of view, the ability to easily distinguish local radio-frequency interference from real signals, and the possibility to localize detected events on the sky to milliarcsecond accuracy. We describe our software pipeline, which accepts short integration ({approx} ms) spectrometer data from each antenna in real time during correlation and performs an incoherent dedispersion separately for each antenna, over a range of trial dispersion measures. The dedispersed data are processed by a sophisticated detector and candidate events are recorded. At the end of the correlation, small snippets of the raw data at the time of the events are stored for further analysis. We present the results of our event detection pipeline from some test observations of the pulsars B0329+54 and B0531+21 (the Crab pulsar).
Wayth, Randall B.; Tingay, Steven J. [International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth, WA 6845 (Australia); Brisken, Walter F.; Deller, Adam T. [NRAO, P.O. Box O, Socorro, NM 87801 (United States); Majid, Walid A.; Thompson, David R.; Wagstaff, Kiri L., E-mail: firstname.lastname@example.com [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)
ISM band to U-NII band frequency transverter and method of frequency transversion
A frequency transverter (10) and method for enabling bi-frequency dual-directional transfer of digitally encoded data on an RF carrier by translating between a crowded or otherwise undesirable first frequency band, such as the 2.4 GHz ISM band, and a less-crowded or otherwise desirable second frequency band, such as the 5.0 GHz 6.0 GHz U-NII band. In a preferred embodiment, the transverter (10) connects between an existing data radio (11) and its existing antenna (30), and comprises a bandswitch (12); an input RF isolating device (14); a transmuter (16); a converter (18); a dual output local oscillator (20); an output RF isolating device (22); and an antenna (24) tuned to the second frequency band. The bandswitch (12) allows for bypassing the transverter (10), thereby facilitating its use with legacy systems. The transmuter (14) and converter (16) are adapted to convert to and from, respectively, the second frequency band.
Stepp, Jeffrey David (Grandview, MO); Hensley, Dale (Grandview, MO)
ISM band to U-NII band frequency transverter and method of frequency transversion
A frequency transverter (10) and method for enabling bi-frequency dual-directional transfer of digitally encoded data on an RF carrier by translating between a crowded or otherwise undesirable first frequency band, such as the 2.4 GHz ISM band, and a less-crowded or otherwise desirable second frequency band, such as the 5.0 GHz-6.0 GHz U-NII band. In a preferred embodiment, the transverter (10) connects between an existing data radio (11) and its existing antenna (30), and comprises a bandswitch (12); an input RF isolating device (14); a transmuter (16); a converter (18); a dual output local oscillator (20); an output RF isolating device (22); and an antenna (24) tuned to the second frequency band. The bandswitch (12) allows for bypassing the transverter (10), thereby facilitating its use with legacy systems. The transmuter (14) and converter (16) are adapted to convert to and from, respectively, the second frequency band.
Stepp, Jeffrey David (Grandview, MO); Hensley, Dale (Grandview, MO)
Resonant circuit which provides dual-frequency excitation for rapid cycling of an electromagnet
Disclosed is a novel ring-magnet control circuit that permits synchrotron repetition rates much higher than the frequency of the sinusoidal guide field of the ring magnet during particle acceleration. The control circuit generates sinusoidal excitation currents of different frequencies in the half waves. During radio-frequency acceleration of the synchrotron, the control circuit operates with a lower frequency sine wave and, thereafter, the electromagnets are reset with a higher-frequency half sine wave.
Praeg, W.F.
X-ray Detection of a Rotating Radio Transient
Abstract �Rotating RAdio Transients � (RRATs) are a newly discovered astronomical phenomenon, characterised by occasional brief radio bursts, with average intervals between bursts ranging from minutes to hours. The burst spacings allow identification of periodicities, which fall in the range 0.4 to 7 seconds. The RRATs thus seem to be rotating neutron stars, albeit with properties very different from the rest of the population. We here present the serendipitous detection with the Chandra X-ray Observatory of a bright point-like X-ray source coincident with one of the RRATs. We discuss the temporal and spectral properties of this X-ray emission, consider counterparts in other wavebands, and interpret these results in the context of possible explanations for the RRAT population.
Bryan M. Gaensler; Maura Mclaughlin; Stephen Reynolds Kazik; Borkowski N; Burgay Fern; Andrew Lyne; Ingrid Stairs; B. M. Gaensler; S. Chatterjee; M. Mclaughlin; S. Reynolds; K. Borkowski; N. Rea; A. Possenti; M. Burgay; Osservatorio Astronomico Di Roma; F. Camilo; M. Kramer; A. Lyne
Amplitude calibration of a digital radio antenna array for measuring cosmic ray air showers
Radio pulses are emitted during the development of air showers, where air showers are generated by ultra-high energy cosmic rays entering the Earth's atmosphere. These nanosecond short pulses are presently investigated by various experiments for the purpose of using them as a new detection technique for cosmic particles. For an array of 30 digital radio antennas (LOPES experiment) an absolute amplitude calibration of the radio antennas including the full electronic chain of the data acquisition system is performed, in order to estimate absolute values of the electric field strength for these short radio pulses. This is mandatory, because the measured radio signals in the MHz frequency range have to be compared with theoretical estimates and with predictions from Monte Carlo simulations to reconstruct features of the primary cosmic particle. A commercial reference radio emitter is used to estimate frequency dependent correction factors for each single antenna of the radio antenna array. The expected received power is related to the power recorded by the full electronic chain. Systematic uncertainties due to different environmental conditions and the described calibration procedure are of order 20%.
S. Nehls; A. Hakenjos; M. J. Arts; J. Bluemer; H. Bozdog; W. A. van Cappellen; H. Falcke; A. Haungs; A. Horneffer; T. Huege; P. G. Isar; O. Kroemer
Broadcasting in unreliable radio networks
Practitioners agree that unreliable links, which sometimes deliver messages and sometime do not, are an important characteristic of wireless networks. In contrast, most theoretical models of radio networks fix a static set ...
Kuhn, Fabian
Broadcasting in Unreliable Radio Networks
Practitioners agree that unreliable links, which fluctuate between working and not working, are an important characteristic of wireless networks. In contrast, most theoretical models of radio networks fix a static set of ...
Oshman, Rotem
Radio frequency waves in the ion cyclotron range of frequencies (ICRF) are widely used to heat tokamak plasmas. In ICRF heating schemes involving multiple ion species, the launched fast waves convert to ion cyclotron waves ...
Jaeger, E. F.
A procedure for oscillatory parameter identification
A procedure is proposed where a power system is excited with a low-level pseduo-random probing signal and the frequency, damping, magnitude, and shape of oscillatory modes are identified using spectral density estimation and frequency-domain transfer-function identification. Attention is focussed on identifying system modes in the presence of noise. Two examples cases are studied: identification of electromechanical oscillation modes in a 16-machine power system; and turbine-generator shaft modes of a 3-machine power plant feeding a series-compensated 500-kV network.
Trudnowski, D.J.; Donnelly, M.K. [Pacific Northwest Lab., Richland, WA (United States); Hauer, J.F. [Bonneville Power Administration, Portland, OR (United States)
A procedure of oscillatory parameter identification
Science Conference Proceedings (OSTI)
A procedure is proposed where a power system is excited with a low-level pseudorandom probing signal and the frequency, damping, magnitude, and shape of oscillatory modes are identified using spectral density estimation and frequency-domain transfer-function identification. Attention is focused on identifying system modes in the presence of noise. Two example cases are studied: identification of electromechanical oscillation modes in a 16-machine power system; and turbine-generator shaft modes of a 3-machine power plant feeding a series-compensated 500-kV network.
Trudnowski, D.J.; Donnelly, M.K. (Pacific Northwest Lab., Richland, WA (United States)); Hauer, J.F. (Bonneville Power Administration, Portland, OR (United States))
Reliable wireless communication links for local-area (short-range) and regional (long-range) reach capabilities are crucial for emergency response to disasters. Lack of a dependable communication system can result in disruptions in the situational awareness between the local responders in the field and the emergency command and control centers. To date, all wireless communications systems such as cell phones and walkie-talkies use narrowband radio frequency (RF) signaling for data communication. However, the hostile radio propagation environment caused by collapsed structures and rubble in various disaster sites results in significant degradation and attenuation of narrowband RF signals, which ends up in frequent communication breakdowns. To address the challenges of reliable radio communication in disaster fields, we propose an approach to use ultra-wideband (UWB) or wideband RF waveforms for implementation on Software Defined Radio (SDR) platforms. Ultra-wideband communications has been proven by many research groups to be effective in addressing many of the limitations faced by conventional narrowband radio technologies. In addition, LLNL's radio and wireless team have shown significant success in field deployment of various UWB communications system for harsh environments based on LLNL's patented UWB modulation and equalization techniques. Furthermore, using software defined radio platform for UWB communications offers a great deal of flexibility in operational parameters and helps the radio system to dynamically adapt itself to its environment for optimal performance.
Nekoogar, F; Dowla, F
We give for a plasma with a history of several expansion and contraction phases an analytical model of the evolution of a contained relativistic electron population under synchrotron, inverse Compton and adiabatic energy losses or gains. This is applied to different scenarios for evolution of radio plasma inside the cocoons of radio galaxies, after the activity of the central engine has ceased. It is demonstrated that fossil radio plasma with an age of even up to 2 Gyr can be revived by compression in a shock wave of large-scale structure formation, caused during the merging events of galaxy clusters, or by the accretion onto galaxy clusters. We argue, that this is a highly plausible explanation for the observed cluster radio relics, which are the regions of diffuse radio emission found in clusters of galaxies, without any likely parent radio galaxy seen nearby. An implication of this model is the existence of a population of diffuse, ultra-steep spectrum, very low frequency radio sources located inside and possibly outside of clusters of galaxies, tracing the revival of aged fossil radio plasma by the shock waves associated with large-scale structure formation.
Torsten A. Ensslin; Gopal-Krishna
Science Conference Proceedings (OSTI)
NIST Home > Time and Frequency Portal. Time and Frequency Portal. Programs and Projects. CODATA values of the fundamental constants ...
Science Conference Proceedings (OSTI)
Some type III bursts are observed to undergo sudden flux modifications, e.g., reductions and intensifications, when type III beams cross shocks in the upper corona or solar wind. First simulations are presented for type III bursts perturbed by weak coronal shocks, which type III beams traverse. The simulations incorporate spatially localized jumps in plasma density and electron and ion temperatures downstream of a shock. A shock is predicted to produce significant modulations to a type III burst: (1) a broadband flux reduction or frequency gap caused by the shock's density jump, (2) a narrowband flux intensification originating from where the downstream plasma density locally has a small gradient, (3) a possible intensification from the shock front or just upstream, and (4) changes in the frequency drift rate profile and the temporal evolution of radiation flux at frequencies corresponding to the shocked plasma. The modulations are caused primarily by fundamental modifications to the radiation processes in response to the shocked density and temperatures. The predicted intensifications and reductions appear qualitatively consistent with the available small number of reported observations, although it is unclear how representative these observations are. It is demonstrated that a weak shock can cause an otherwise radio-quiet type III beam to produce observable levels of narrowband radio emission. The simulations suggest that type III bursts with frequency-time fine structures may provide a tool to probe shocks in the corona and solar wind, especially for weak shocks that do not radiate by themselves.
Li, B.; Cairns, Iver H. [School of Physics, University of Sydney, New South Wales 2006 (Australia)
Relationship between Frequency of RFID Tags and Its Ability to Penetrate Fresh Concrete
The concrete maturity method can be utilized to determine in situ strength of concrete. It uses the temperature of concrete to determine a maturity index that can then be used to determine strength of concrete. However, monitoring the concrete temperature using thermocouples brings up a wiring issue, which is not advisable in an equipment and human intensive area like a construction site. One of the ways to get around this wiring issue is to use Radio Frequency Identification (RFID) technology, which is capable of transmitting information wirelessly. Previous research implemented using ultra high frequency RFID tags embedded in fresh concrete found that water could be the impediment for transmitting RFID signal from within concrete during early stages of curing. From literature it was found that lower the frequency, better the chances of the wave penetrating water. The objective of the research was to figure out whether the frequency of RFID tags has any relationship with the readability of RFID tags embedded in fresh concrete. For this investigation, low frequency, high frequency, and ultra high frequency RFID tags were tested within fresh concrete to see any difference between tags in terms of transmitting information. This experiment was carried out in a controlled space to reduce the number of variables affecting the experiment outcome. The low frequency, high frequency, and ultra high frequency RFID tags were placed within 2 in x 3 in x 2 in wooden formwork at a depth of 4 in, 8 in, and 12 in. Ready mix concrete was poured into the formwork and 3 concrete cubes were cast with the tags embedded within them. Readers that could be connected to a laptop were used to monitor and collect the time at which these RFID tags can be detected. The test showed that the RFID signals from the low frequency tags at all depths were detected as soon as concrete was poured. The Ultra High Frequency tags placed at the 4" level could be detected 15 minutes after concrete was poured. The UHF tags at the 8" level could be detected after 30 minutes. The UHF tags at the 12" level took on an average 2 hours to be detected from the vicinity of the formwork. The greater the depth at which the ultra high frequency tag was buried the longer it took for it to be detected. The high frequency tags could be detected only at the 4" level. The reason the performance of the HF card degraded in concrete could be because it uses an aluminum foil antenna which is more susceptible to the environment changing the relative permeability. A copper wire antenna could have fared better in this condition, increasing the chances of detecting the tag. Moreover a passive tag was used. The read range and chances of detection could have been increased had an active tag been used. The power of the reader that was used was also very less which might have contributed to the tag not being detected. Among the tags that were used in the experiment it was found that low frequency tags was the tag that could be detected the earliest after concrete was poured into the forms. However, the maximum read range of the tag observed in the experiment was 20" which is too small a distance to be used on an actual construction site.
Sridharan, Rajasekaran
Science Conference Proceedings (OSTI)
A quantitative study of the observable radio signatures of the sausage, kink, and torsional magnetohydrodynamic (MHD) oscillation modes in flaring coronal loops is performed. Considering first non-zero order effect of these various MHD oscillation modes on the radio source parameters such as magnetic field, line of sight, plasma density and temperature, electron distribution function, and the source dimensions, we compute time-dependent radio emission (spectra and light curves). The radio light curves (of both flux density and degree of polarization) at all considered radio frequencies are then quantified in both time domain (via computation of the full modulation amplitude as a function of frequency) and in Fourier domain (oscillation spectra, phases, and partial modulation amplitude) to form the signatures specific to a particular oscillation mode and/or source parameter regime. We found that the parameter regime and the involved MHD mode can indeed be distinguished using the quantitative measures derived in the modeling. We apply the developed approach to analyze radio burst recorded by Owens Valley Solar Array and report possible detection of the sausage mode oscillation in one (partly occulted) flare and kink or torsional oscillations in another flare.
Mossessian, George; Fleishman, Gregory D. [Center For Solar-Terrestrial Research, New Jersey Institute of Technology, Newark, NJ 07102 (United States)
Radio detection of high-energy cosmic rays at the Pierre Auger Observatory
The southern Auger Observatory provides an excellent test bed to study the radio detection of extensive air showers as an alternative, cost-effective, and accurate tool for cosmic-ray physics. The data from the radio setup can be correlated with those from the well-calibrated baseline detectors of the Pierre Auger Observatory. Furthermore, human-induced radio noise levels at the southern Auger site are relatively low. We have started an R&D program to test various radio-detection concepts. Our studies will reveal Radio Frequency Interferences (RFI) caused by natural effects such as day-night variations, thunderstorms, and by human-made disturbances. These RFI studies are conducted to optimise detection parameters such as antenna design, frequency interval, antenna spacing and signal processing. The data from our initial setups, which presently consist of typically 3 - 4 antennas, will be used to characterise the shower from radio signals and to optimise the initial concepts. Furthermore, the operation of a large detection array requires autonomous detector stations. The current design is aiming at stations with antennas for two polarisations, solar power, wireless communication, and local trigger logic. The results of this initial phase will provide an important stepping stone for the design of a few tens kilometers square engineering array
A. M. van den Berg; for the Pierre Auger Collaboration
Synchronizing carrier frequencies of co-channel amplitude-modulated broadcast
Systems and methods are described for carrier-frequency synchronization for improved AM and TV broadcast reception. A method includes synchronizing a carrier frequency of a broadcast signal with a remote reference frequency. An apparatus includes a reference signal receiver; a phase comparator coupled to the reference signal receiver; a voltage controlled oscillator coupled to the phase comparator; and a radio frequency output coupled to the voltage controlled oscillator.
Smith, Stephen F. (London, TN); Moore, James A. (Powell, TN)
RapidRadio: Signal Classification and Radio Deployment Framework
Science Conference Proceedings (OSTI)
In this article, the RapidRadio framework for signal classification and receiver deployment is discussed. The framework is a productivity-enhancing tool that reduces the required knowledge base for implementing a receiver on an FPGA-based SDR platform. ... Keywords: FPGA, signal classification, system synthesis
Jorge A. Sur�s; Adolfo Recio; Peter Athanas
Measurements of the effects of humidity on radio-aerosol penetration through ultrafine capillaries
The purpose of this research was to examine the effects of humidity on radio-aerosol penetration through ultrafine capillaries. A number of tests were conducted at relative humidities of 20%, 50%, and 80%, with sampling times of 20, 40, and 60 min. The radio-aerosol consisted of polystyrene particles with a diameter of 0.1 {micro}m. The ultrafine capillaries had a diameter of 250 {micro}m. The data from these tests varied significantly. These results made the identification of radio-aerosol penetration trends inconclusive. The standard deviation for all penetration data ranged from 3% to 30%. The results of this study suggest that a better control of the experimental parameters was needed to obtain more accurate data from experiments associated with radio-aerosol penetration in the presence of moisture. The experimental parameters that may have contributed to the wide variance of data, include aerosol flow, radio-aerosol generation, capillary characteristics, humidity control, and radiation measurements. It was the uncertainty of these parameters that contributed to the poor data which made conclusive deductions about radio-aerosol penetration dependence on humidity difficult. The application of this study is to ultrafine leaks resulting from stress fractures in high-level nuclear waste transportation casks under accident scenarios.
Cullen, C.
Comparison between Poissonian and Markovian Primary Traffics in Cognitive Radio Networks
Cognitive Radio generates a big interest as a key cost-effective solution for the underutilization of frequency spectrum in legacy communication networks. The objective of this work lies in conducting a performance evaluation of the end-to-end message delivery under both Markovian and Poissonian primary traffics in lossy Cognitive Radio networks. We aim at inferring the most appropriate conditions for an efficient secondary service provision according to the Cognitive Radio network characteristics. Meanwhile, we have performed a general analysis for many still open issues in Cognitive Radio, but at the end only two critical aspects have been considered, namely, the unforeseen primary reclaims in addition to the collided cognitive transmissions due to the Opportunistic Spectrum Sharing. Some graphs, in view of the average Spectral Efficiency, have been computed and plotted to report some comparative results for a given video transmission under the Markovian and the Poissonian primary interruptions.
Chaoub, Abdelaali
Cognitive radio: an enabling technology for the green radio communications concept
Science Conference Proceedings (OSTI)
In this paper, Cognitive Radio (CR) is proposed as an efficient technology to meet the Green communications concept. First of all, the concept of "green communications" is extended to the radio communications world. The main topics, described for example ... Keywords: cognitive radio, consumption, electromagnetic pollution, green communications, health, peak-to-average power ratio (PAPR), radio communications, sustainable development
Jacques Palicot
Radio access network power management considering radio over fiber technique for 4G mobile system
Science Conference Proceedings (OSTI)
Radio over fiber technique was suggested as excelent candidates for 4G radio access network considering large number mobile users. With higher number of base stations, a microwave link presents more disadvantages across base stations in relation to power ... Keywords: 4G mobile system, fiber dispersion, power manaegment, radio access network, radio over fiber
Jalal J. Hamad Ameen; Widad Ismail; Sevia M. Idrus
A ubiquitous mobile telemedicine system for the elderly using RFID
Science Conference Proceedings (OSTI)
The last two years have witnessed an explosion of interest in Radio-Frequency Identification (RFID) and mobile technologies. Radio frequency identification systems have many applications in manufacturing, supply chain and healthcare. In an ... Keywords: ADL, RFID, WIFI network, chronic diseases, elderly, electrocardiograms, emergency situations, healthcare technology, mobile telemedicine, radio frequency identification, smart cards, ubiquitous, vital signs, wearable RFID tags
Muhammad Wassim Raad
The 2001 April 15 event was one of the largest of the last solar cycle. A former study established that this event was associated with a coronal mass ejection (CME) observed both at white light and radio frequencies. This radio CME is illuminated by synchrotron emission from relativistic electrons. In this paper, we investigate the relation of the radio CME to its extreme-ultraviolet (EUV) and white-light counterpart and reach four main conclusions. (1) The radio CME corresponds to the white-light flux rope cavity. (2) The presence of a reconnecting current sheet behind the erupting flux rope is framed, both from below and above, by bursty radio sources. This reconnection is the source of relativistic radiating electrons which are injected down along the reconnected coronal arches and up along the flux rope border forming the radio CME. (3) Radio imaging reveals an important lateral overexpansion in the low corona; this overexpansion is at the origin of compression regions where type II and III bursts are imaged. (4) Already in the initiation phase, radio images reveal large-scale interactions of the source active region (AR) with its surroundings, including another AR and open magnetic fields. Thus, these complementary radio, EUV, and white-light data validate the flux rope eruption model of CMEs.
Demoulin, P.; Pick, M.; Bouteille, A. [LESIA, UMR 8109 CNRS, UPMC, Universite Paris-Diderot, Observatoire de Paris-Meudon, Meudon 92195 (France); Vourlidas, A., E-mail: email@example.com [Space Sciences Division, Naval Research Laboratory, Washington, DC 20375 (United States)
Using the Sloan Digital Sky Survey (SDSS) and the Faint Images of the Radio Sky at Twenty Centimeters (FIRST) catalogs, we examined the optical environments around double-lobed radio sources. Previous studies have shown that multi-component radio sources exhibiting some degree of bending between components are likely to be found in galaxy clusters. Often this radio emission is associated with a cD-type galaxy at the center of a cluster. We cross-correlated the SDSS and FIRST catalogs and measured the richness of the cluster environments surrounding both bent and straight multi-component radio sources. This led to the discovery and classification of a large number of galaxy clusters out to a redshift of z {approx} 0.5. We divided our sample into smaller subgroups based on their optical and radio properties. We find that FR I radio sources are more likely to be found in galaxy clusters than FR II sources. Further, we find that bent radio sources are more often found in galaxy clusters than non-bent radio sources. We also examined the environments around single-component radio sources and find that single-component radio sources are less likely to be associated with galaxy clusters than extended, multi-component radio sources. Bent, visually selected sources are found in clusters or rich groups {approx}78% of the time. Those without optical hosts in SDSS are likely associated with clusters at even higher redshifts, most with redshifts of z>0.7.
Wing, Joshua D.; Blanton, Elizabeth L., E-mail: email@example.com [Astronomy Department and Institute for Astrophysical Research, Boston University, Boston, MA 02215 (United States)
'Pirate' radio, convergence and reception in Zimbabwe
Science Conference Proceedings (OSTI)
Using a qualitative research approach, this study examines the appropriation of digital technologies and their implications for the reception of the so-called 'pirate' radio in Zimbabwe. It specifically explores how the use of the Internet (and its associated ... Keywords: Convergence, Internet, Mobile phone, Oral tradition, Pirate radio, Reception, SMS, SW Radio Africa, Studio 7, Zimbabwe
Hayes Mawindi Mabweazara
We present a catalog of radio afterglow observations of gamma-ray bursts (GRBs) over a 14 year period from 1997 to 2011. Our sample of 304 afterglows consists of 2995 flux density measurements (including upper limits) at frequencies between 0.6 GHz and 660 GHz, with the majority of data taken at 8.5 GHz frequency band (1539 measurements). We use this data set to carry out a statistical analysis of the radio-selected sample. The detection rate of radio afterglows has stayed unchanged almost at 31% before and after the launch of the Swift satellite. The canonical long-duration GRB radio light curve at 8.5 GHz peaks at three to six days in the source rest frame, with a median peak luminosity of 10{sup 31} erg s{sup -1} Hz{sup -1}. The peak radio luminosities for short-hard bursts, X-ray flashes, and the supernova-GRB classes are an order of magnitude or more fainter than this value. There are clear relationships between the detectability of a radio afterglow and the fluence or energy of a GRB, and the X-ray or optical brightness of the afterglow. However, we find few significant correlations between these same GRB and afterglow properties and the peak radio flux density. We also produce synthetic light curves at centimeter and millimeter bands using a range of blast wave and microphysics parameters derived from multiwavelength afterglow modeling, and we use them to compare to the radio sample. Finding agreement, we extrapolate this behavior to predict the centimeter and millimeter behavior of GRBs observed by the Expanded Very Large Array and the Atacama Large Millimeter Array.
Chandra, Poonam [Department of Physics, Royal Military College of Canada, Kingston, ON K7M3C9 (Canada); Frail, Dale A., E-mail: email@example.com [National Radio Astronomy Observatory, Socorro, NM 87801 (United States)
Optimal monitoring in multi-channel multi-radio wireless mesh networks
Science Conference Proceedings (OSTI)
Wireless mesh networks (WMN) are finding increasing usage in city-wide deployments for providing network connectivity. Mesh routers in WMNs typically use multiple wireless channels to enhance the spatial-reuse of frequency bands, often with multiple ... Keywords: approximation algorithm, lp rounding, multi-channel multi-radio wireless networks, security monitoring, wireless mesh networks
Dong-Hoon Shin; Saurabh Bagchi
Parallel radio-wave propagation modeling with image-based ray tracing techniques
Science Conference Proceedings (OSTI)
Ray tracing is a technique based on the numerical simulation of geometrical optics and the uniform theory of diffraction, two well-known approximate methods for estimating a high-frequency electromagnetic field, based on the ray theory of field propagation. ... Keywords: Load balancing, Message passing interface, Performance evaluation, Radio-wave propagation, Ray tracing, Wireless communications
T. E. Athanaileas; G. E. Athanasiadou; G. V. Tsoulos; D. I. Kaklamani
A 610-MHz Galactic Plane Pulsar Search with the Giant Meterwave Radio Telescope
We report on the discovery of three new pulsars in the first blind survey of the north Galactic plane (45 < l < 135 ; |b| < 1) with the Giant Meterwave Radio telescope (GMRT) at an intermediate frequency of 610 MHz. The timing parameters, obtained in follow up observations with the Lovell Telescope at Jodrell Bank Observatory and the GMRT, are presented.
B. C. Joshi; M. A. McLaughlin; M. Kramer; A. G. Lyne; D. R. Lorimer; D. A. Ludovici; M. Davies; A. J. Faulkner
Science Conference Proceedings (OSTI)
We study the radio spectra of two magnetars, PSR J1550-5418 and J1622-4950. We argue that they are good candidates for pulsars with gigahertz-peaked spectra (GPS), as their observed flux density decreases at frequencies below 7 GHz. We suggest that this behavior is due to the influence of the pulsars' environments on radio waves. Both of the magnetars are associated with supernova remnants and thus are surrounded by hot, ionized gas, which can be responsible for the free-free absorption of radio waves. We conclude that the GPS feature of both magnetars and typical pulsars are formed by similar processes in the surrounding media rather than by different radio-emission mechanisms. Thus, the radio magnetars PSR J1550-5418 and J1622-4950 can be included in the class of GPS pulsars.
Kijak, J.; Tarczewski, L.; Lewandowski, W. [Kepler Institute of Astronomy, University of Zielona Gora, Lubuska 2, 65-265 Zielona Gora (Poland); Melikidze, G., E-mail: firstname.lastname@example.com [Also at Abastumani Astrophysical Observatory, Ilia State University, 3-5 Cholokashvili Avenue, Tbilisi 0160, Georgia. (Georgia)
Performance enhancement of the EPCglobal network by aggregating data at the EPCIS.
??RFID is a well known acronym for Radio-Frequency Identification, which is a technology similar to the existing bar code identification. This particular technology is capable� (more)
Conganige, Ruvin Anthony
A self-calibration scheme for extended frequency-band-decomposition sigma-delta ADC
Science Conference Proceedings (OSTI)
Frequency-band-decomposition (FBD) is a good candidate to be used to increase the bandwidths of ADC converters based on sigma-delta modulators for software and cognitive radio applications where we need to convert wide bandwidths. Each modulator processes ... Keywords: Analog-to-digital conversion, Bandpass, Filter bank, Frequency-band-decomposition, Self-calibration, Sigma-delta
Philippe Benabes; Ali Beydoun
Radio astronomical imaging in the presence of strong radio interference
Abstract�Radio-astronomical observations are increasingly contaminated by interference, and suppression techniques become essential. A powerful candidate for interference mitigation is adaptive spatial filtering. We study the effect of spatial filtering techniques on radio-astronomical imaging. Current deconvolution procedures, such as CLEAN, are shown to be unsuitable for spatially filtered data, and the necessary corrections are derived. To that end, we reformulate the imaging (deconvolution/calibration) process as a sequential estimation of the locations of astronomical sources. This not only leads to an extended CLEAN algorithm, but also the formulation allows the insertion of other array signal processing techniques for direction finding and gives estimates of the expected image quality and the amount of interference suppression that can be achieved. Finally, a maximum-likelihood (ML) procedure for the imaging is derived, and an approximate ML image formation technique is proposed to overcome the computational burden involved. Some of the effects of the new algorithms are shown in simulated images. Index Terms�CLEAN, interference mitigation, maximum likelihood, minimum variance, parametric imaging, radio astronomy, spatial filtering, synthesis imaging. I.
Amir Leshem; Alle-jan Van Der Veen
Electromagnetic Compatibility from a Time-Frequency Perspective
Abstract � In wireless communication, interference between two radio systems may occur when they operate at close frequency bands, sharing the same environment at the same time. Such systems coexist if both of them perform correctly in the presence of the other. To ensure their coexistence, Electromagnetic Compatibility (EMC) is used to specify rules within standardization bodies. According to current EMC standards, the radio spectrum has been divided into non-overlapping bands often with exclusive access. However, nowadays there is a proliferation of new digital systems sharing common frequency bands because the spectrum is a limited resource. Many of them are operating in unlicensed bands regulated by The International Telecommunications Union (ITU), for example the 2.45 GHz Industrial, Scientific and Medical (ISM) band. The frequency allocation is also changing with the emergence of digital systems and this is the case for white spaces in the broadcast television (TV) spectrum. To avoid high interference levels, it is necessary to consider some parameters related to signal variations, representing more accurately the environment. Some techniques have been proposed in the literature to reduce interference levels but they are applied to specific sharing studies. Hence, we evaluate in this paper the impact of time-frequency considerations for radio coexistence. We show that EMC studies are more precise and more representative of the reality when additional parameters relevant to the time domain are taken into account in the analysis framework. We illustrate these concepts through a specific study case. We evaluate the results for different system parameters, first considering that both of them occupy the same band and then assuming that they use overlapping but non-equal frequency bands. Index Terms � Radio coexistence, electromagnetic compatibility, frequency-domain analysis, time-domain analysis.
Najett Neji; Raul De Lacerda; Alain Azoulay; Thierry Letertre
Science Conference Proceedings (OSTI)
This Letter presents the results of studies of solar cycle variations of the occurrence rate of coronal type III radio bursts. The radio spectra are provided by the Learmonth Solar Radio Observatory (Western Australia), part of the USAF Radio Solar Telescope Network (RSTN). It is found that the occurrence rate of type III bursts strongly correlates with solar activity. However, the profiles for the smoothed type III burst occurrence rate differ considerably from those for the sunspot number, 10.7 cm solar radio flux, and solar flare index. The type III burst occurrence rate (T3BOR) is proposed as a new index of solar activity. T3BOR provides complementary information about solar activity and should be useful in different studies including solar cycle predictions and searches for different periodicities in solar activity. This index can be estimated from daily results of the Automated Radio Burst Identification System. Access to data from other RSTN sites will allow processing 24 hr radio spectra in near-real time and estimating true daily values of this index. It is also shown that coronal type III bursts can even occur when there are no visible sunspots on the Sun. However, no evidence is found that the bursts are not associated with active regions. It is also concluded that the type III burst productivity of active regions exhibits solar cycle variations.
Lobzin, Vasili; Cairns, Iver H.; Robinson, Peter A. [School of Physics, University of Sydney, New South Wales (Australia)
The Triggering and Bias of Radio Galaxies
We present new results on the clustering and three-dimensional distribution of radio galaxies from the Texas-Oxford NVSS Structure (TONS) survey. The TONS survey was constructed to look at the distribution of radio galaxies in a region of moderate (0 3 mJy) radio galaxies over large areas on the sky. We find that redshift spikes, which represent large concentrations of radio galaxies which trace (~ 100 Mpc^3) super-structures are a common phenomena in these surveys. Under the assumption of quasi-linear structure formation theory and a canonical radio galaxy bias, the structures represent ~ 4-5 sigma peaks in the primordial density field and their expected number is low. The most plausible explanation for these low probabilities is an increase in the radio galaxy bias with redshift. To investigate potential mechanisms which have triggered the radio activity in these galaxies - and hence may account for an increase in the bias of this population, we performed imaging studies of the cluster environment of the radio galaxies in super-structure regions. Preliminary results show that these radio galaxies may reside preferentially at the edges of rich clusters. If radio galaxies are preferentially triggered as they fall towards rich clusters then they would effectively adopt the cluster bias.
Kate Brand; Steve Rawlings; Joe Tufts; Gary Hill
Survey on solar X-ray flares and associated coherent radio emissions
The radio emission during 201 X-ray selected solar flares was surveyed from 100 MHz to 4 GHz with the Phoenix-2 spectrometer of ETH Zurich. The selection includes all RHESSI flares larger than C5.0 jointly observed from launch until June 30, 2003. Detailed association rates of radio emission during X-ray flares are reported. In the decimeter wavelength range, type III bursts and the genuinely decimetric emissions (pulsations, continua, and narrowband spikes) were found equally frequently. Both occur predominantly in the peak phase of hard X-ray (HXR) emission, but are less in tune with HXRs than the high-frequency continuum exceeding 4 GHz, attributed to gyrosynchrotron radiation. In 10% of the HXR flares, an intense radiation of the above genuine decimetric types followed in the decay phase or later. Classic meter-wave type III bursts are associated in 33% of all HXR flares, but only in 4% they are the exclusive radio emission. Noise storms were the only radio emission in 5% of the HXR flares, some of them with extended duration. Despite the spatial association (same active region), the noise storm variations are found to be only loosely correlated in time with the X-ray flux. In a surprising 17% of the HXR flares, no coherent radio emission was found in the extremely broad band surveyed. The association but loose correlation between HXR and coherent radio emission is interpreted by multiple reconnection sites connected by common field lines.
Arnold O. Benz; Paolo Grigis; Andre Csillagy; Pascal Saint-Hilaire
The commonly used classical equipartition or minimum-energy estimate of total magnetic fields strengths from radio synchrotron intensities is of limited practical use because it is based on the hardly known ratio K of the total energies of cosmic ray protons and electrons and also has inherent problems. We present a revised formula, using the number density ratio K for which we give estimates. For particle acceleration in strong shocks K is about 40 and increases with decreasing shock strength. Our revised estimate for the field strength gives larger values than the classical estimate for flat radio spectra with spectral indices of about 0.5-0.6, but smaller values for steep spectra and total fields stronger than about 10 muG. In very young supernova remnants, for example, the classical estimate may be too large by up to 10x. On the other hand, if energy losses of cosmic ray electrons are important, K increases with particle energy and the equipartition field may be underestimated significantly. Our revised larger equipartition estimates in galaxy clusters and radio lobes are consistent with independent estimates from Faraday rotation measures, while estimates from the ratio between radio synchrotron and X-ray inverse Compton intensities generally give much weaker fields. This may be explained e.g. by a concentration of the field in filaments. Our revised field strengths may also lead to major revisions of electron lifetimes in jets and radio lobes estimated from the synchrotron break frequency in the radio spectrum.
Rainer Beck; Marita Krause
A Search for the Radio Counterpart to the March 1, 1994 Gamma Ray Burst
We report on the results of a search for the radio counterpart to the bright gamma-ray burst of March 1, 1994. Using the Dominion Radio Astrophysical Observatory Synthesis Telescope sensitive, wide-field radio images at 1.4 GHz and 0.4 GHz were made of a region around GRB940301. A total of 15 separate radio images were obtained at each frequency, sampling a near-continuous range of post-burst timescales between 3 and 15 days, as well as 26, 47 and 99 days. We place an upper limit of 3.5 mJy on a fading/flaring radio counterpart at 1.4 GHz and 55 mJy at 0.4 GHz. Previous searches have concentrated on searching for a counterpart at only one epoch following the outburst. In contrast, the present search maintains high sensitivity over two decades of post-burst time durations. Time-variable radio emission after the initial gamma-ray burst is a prediction of all fireball models, currently the most popular model for gamma-ray bursts. Our observations allow us to put significant constraints on the fireball parameters for cosmological models of gamma-ray bursts.
Frail; Kulkarni; Hurley; Fishman; Kouveliotou; Meegan; Sommer; Boer; Niel; Cline
A new generation of low-frequency radio telescopes is seeking to observe the redshifted 21 cm signal from the epoch of reionization (EoR), requiring innovative methods of calibration and imaging to overcome the difficulties of wide-field low-frequency radio interferometry. Precise calibration will be required to separate the expected small EoR signal from the strong foreground emission at the frequencies of interest between 80 and 300 MHz. The Moon may be useful as a calibration source for detection of the EoR signature, as it should have a smooth and predictable thermal spectrum across the frequency band of interest. Initial observations of the Moon with the Murchison Widefield Array 32 tile prototype show that the Moon does exhibit a similar trend to that expected for a cool thermally emitting body in the observed frequency range, but that the spectrum is corrupted by reflected radio emission from Earth. In particular, there is an abrupt increase in the observed flux density of the Moon within the internationally recognized frequency modulated (FM) radio band. The observations have implications for future low-frequency surveys and EoR detection experiments that will need to take this reflected emission from the Moon into account. The results also allow us to estimate the equivalent isotropic power emitted by the Earth in the FM band and to determine how bright the Earth might appear at meter wavelengths to an observer beyond our own solar system.
McKinley, B.; Briggs, F. [Research School of Astronomy and Astrophysics, Australian National University, Canberra (Australia); Kaplan, D. L. [Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI (United States); Greenhill, L. J.; Bernardi, G.; De Oliveira-Costa, A. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Bowman, J. D. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ (United States); Tingay, S. J.; Gaensler, B. M. [ARC Centre of Excellence for All-Sky Astrophysics (CAASTRO), School of Physics, The University of Sydney, Sydney, NSW (Australia); Oberoi, D. [National Centre for Radio Astrophysics, Tata Institute for Fundamental Research, Pune (India); Johnston-Hollitt, M. [School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington (New Zealand); Arcus, W.; Emrich, D. [International Centre for Radio Astronomy Research, Curtin University, Perth (Australia); Barnes, D. [Center for Astrophysics and Supercomputing, Swinburne University of Technology, Melbourne (Australia); Bunton, J. D. [CSIRO Astronomy and Space Science, Canberra (Australia); Cappallo, R. J.; Corey, B. E. [MIT Haystack Observatory, Westford, MA (United States); Deshpande, A. [Raman Research Institute, Bangalore (India); DeSouza, L. [Sydney Institute for Astronomy, School of Physics, University of Sydney, Sydney (Australia); Goeke, R. [MIT Kavli Institute for Astrophysics and Space Research, Cambridge, MA (United States); and others
High-resolution radio observations of submillimetre galaxies
We have produced sensitive, high-resolution radio maps of 12 SMGs in the Lockman Hole using combined MERLIN and VLA data at a frequency of 1.4 GHz. Integrating for 350hr yielded an r.m.s. noise of 6.0 uJy/beam and a resolution of 0.2-0.5". For the first time, wide-field data from the two arrays have been combined in the (u,v) plane and the bandwidth smearing response of the VLA data has been removed. All of the SMGs are detected in our maps as well as sources comprising a non-submm luminous control sample. We find evidence that SMGs are more extended than the general uJy radio population and that therefore, unlike in local ULIRGs, the starburst component of the radio emission is extended and not confined to the galactic nucleus. For the eight sources with redshifts we measure linear sizes between 1 and 8 kpc with a median of 5 kpc. Therefore, they are in general larger than local ULIRGs which may support an early-stage merger scenario for the starburst trigger. X-rays betray AGN in six of the 33 sources in the combined sample. All but one of these are in the control sample, suggesting a lower incidence of AGN amongst the submm-luminous galaxies which is, in turn, consistent with increased X-ray absorption in these dust-obscured starbursts. Only one of our sources is resolved into multiple, distinct components with our high-resolution data. Finally, compared to a previous study of faint radio sources in the GOODS-N field we find systematically smaller source sizes and no evidence for a tail extending to ~4". Possible reasons for this are discussed.
A. D. Biggs; R. J. Ivison
Using a novel technique, we achieve {approx}100 picoarcsec resolution and set an upper bound of less than 4 km for the characteristic size of the Vela pulsar's emission region. Specifically, we analyze flux-density statistics of the Vela pulsar at 760 MHz. Because the pulsar exhibits strong diffractive scintillation, these statistics convey information about the spatial extent of the radio emission region. We measure both a characteristic size of the emission region and the emission sizes for individual pulses. Our results imply that the radio emission altitude for the Vela pulsar at this frequency is less than 340 km.
Johnson, M. D.; Gwinn, C. R. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Demorest, P., E-mail: firstname.lastname@example.com, E-mail: email@example.com, E-mail: email@example.com [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22093 (United States)
The depolarisation properties of powerful extragalactic radio sources as a function of cosmic epoch
We use the observed polarisation properties of a sample of 26 powerful radio galaxies and radio-loud quasars to constrain the conditions in the Faraday screens local to the sources. We adopt the cosmological redshift, low-frequency radio luminosity and physical size of the large-scale radio structures as our `fundamental' parameters. We find no correlation of the radio spectral index with any of the fundamental parameters. The observed rotation measure is also independent of these parameters. The difference between the rotation measures of the two lobes of an individual source as well as the dispersion of the rotation measure show significant correlations with the source redshift, but not with the radio luminosity or source size. Thus the small-scale structure observed in the rotation measure is caused by a Faraday screen local to the sources. The observed asymmetries between the lobes of our sources show no significant trends with each other or other source properties. Finally, we show that the commonly used model for the depolarisation of synchrotron radio emission by foreground Faraday screens is inconsistent with our observations. We apply alternative models to our data and show that they require a strong increase of the dispersion of the rotation measure inside the Faraday screens with cosmological redshift. Correcting our observations with these models for redshift effects, we find a strong correlation of the depolarisation measure with redshift and a significantly weaker correlation with radio luminosity. All our results are consistent with a decrease in the order of the magnetic field structure of the Faraday screen local to the sources for increasing cosmological redshift. (abridged)
J. A. Goodlet; C. R. Kaiser
Post-outburst radio observation of the region around McNeil's nebula (V1647 Ori)
We present post-outburst (~ 100 days after outburst) radio continuum observation of the region (~ 30' x 30') around McNeil's nebula (V1647 Orionis). The observations were carried out using the Giant Metrewave Radio Telescope (GMRT), India, at 1272 MHz on 2004 Feb 14.5 UT. Although 8 sources have been detected within a circular diameter of 25' centred on V1647 Ori, we did not detect any radio continuum emission from McNeil's nebula. We assign a 5-sigma upper limit of 0.15 mJy/beam for V1647 Ori where the beam size is 5.6" x 2.7". Even at higher frequencies of 4.9 and 8.5 GHz (VLA archival data), no radio emission has been detected from this region. Three scenarios namely, emission from homogeneous HII region, ionised stellar wind and shock ionised gas, are explored in the light of our GMRT upper-limit. For the case of homogeneous HII region, the radius of the emitting region is constrained to be ~ 2,500 K, which is consistent with the reported radio and H-alpha emission. In the ionised stellar wind picture, our upper limit of radio emission translates to the ratio of mass loss rate and terminal velocity, (M_dot/v_infinity) wind shocks the dense neutral (molecular) cloud, the radio upper limit implies that the fraction of the wind encountering the dense obstacle is ~ 7.2 x 10^7 cm^(-3) of the radio emitting plasma have been constrained using a two phase medium in pressure equilibrium for a volume filling factor of 0.9.
S. Vig; S. K. Ghosh; V. K. Kulkarni; D. K. Ojha
With the goal of identifying high redshift radio galaxies with FRI classification, here are presented high resolution, wide-field radio observations, near infra-red and optical imaging and multi-object spectroscopy of two fields of the Leiden-Berkeley Deep Survey. These fields, Hercules.1 and Lynx.2, contain a complete sample of 81 radio sources with S(1.4 GHz) > 0.5 mJy within 0.6 square degrees. This sample will form the basis for a study of the population and cosmic evolution of high redshift, low power, FRI radio sources which will be presented in Paper II. Currently, the host galaxy identification fraction is 86% with 11 sources remaining unidentified at a level of r > 25.2 mag (Hercules; 4 sources) or r > 24.4 mag (Lynx; 7 sources) or K > 20 mag. Spectroscopic redshifts have been determined for 49% of the sample and photometric redshift estimates are presented for the remainder of the sample.
Rigby, E E; Best, P N
With the goal of identifying high redshift radio galaxies with FRI classification, here are presented high resolution, wide-field radio observations, near infra-red and optical imaging and multi-object spectroscopy of two fields of the Leiden-Berkeley Deep Survey. These fields, Hercules.1 and Lynx.2, contain a complete sample of 81 radio sources with S(1.4 GHz) > 0.5 mJy within 0.6 square degrees. This sample will form the basis for a study of the population and cosmic evolution of high redshift, low power, FRI radio sources which will be presented in Paper II. Currently, the host galaxy identification fraction is 86% with 11 sources remaining unidentified at a level of r > 25.2 mag (Hercules; 4 sources) or r > 24.4 mag (Lynx; 7 sources) or K > 20 mag. Spectroscopic redshifts have been determined for 49% of the sample and photometric redshift estimates are presented for the remainder of the sample.
E. E. Rigby; I. A. Snellen; P. N. Best
NIST Radio Station WWV Broadcast Format
Science Conference Proceedings (OSTI)
... 2, Space Weather for the past 24 hours has been severe. Solar radiation storm(s) reaching the S4 level is in progress. Radio ...
Science Conference Proceedings (OSTI)
... 2, Space Weather for the past 24 hours has been severe. Solar radiation storm(s) reaching the S4 level is in progress. Radio ...
Science Conference Proceedings (OSTI)
Return to Table of Contents NIST Recommended Rest Frequencies for Observed Interstellar Molecular Microwave Transitions. by Frank J. Lovas. ...
Eastern Frequency Response Study
Science Conference Proceedings (OSTI)
This study was specifically designed to investigate the frequency response of the Eastern Interconnection that results from large loss-of-generation events of the type targeted by the North American Electric Reliability Corp. Standard BAL-003 Frequency Response and Frequency Bias Setting (NERC 2012a), under possible future system conditions with high levels of wind generation.
Miller, N.W.; Shao, M.; Pajic, S.; D'Aquila, R.
Hanford Identification (HID) PIA, Richland Operations Office...
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
Identification (HID) PIA, Richland Operations Office Hanford Identification (HID) PIA, Richland Operations Office Hanford Identification (HID) PIA, Richland Operations Office...
Hanford Identification (HID) PIA, Richland Operations Office...
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
Hanford Identification (HID) PIA, Richland Operations Office Hanford Identification (HID) PIA, Richland Operations Office Hanford Identification (HID) PIA, Richland Operations...
New radio observations of QSO 0957+561 confirm optical-to radio time delay
In our previous publications have been reported about possible time delay between optical and radio (6 cm) variations in QSO 0957+561 and noted that the result can be tested with new radio observations. Here we have made this test using new published (Haarasma et al., 1999) radio observations of the object in 6 cm and 4 cm. We have found that the new observations confirm optical-to-radio time delay. Additionally we have found that radio 6 cm variations followed 4 cm ones with time delay about 230 days. Obtained results imply existence of the variable beamed hard radiation in the nucleus of the QSO.
V. L. Oknyanskij
This paper introduces a machine learning based collaborative multi band spectrum sensing policy for cognitive radios. The proposed sensing policy guides secondary users to focus the search of unused radio spectrum to those frequencies that persistently provide them high data rate. The proposed policy is based on machine learning, which makes it adaptive with the temporally and spatially varying radio spectrum. Furthermore, there is no need for dynamic modeling of the primary activity since it is implicitly learned over time. Energy efficiency is achieved by minimizing the number of assigned sensors per each subband under a constraint on miss detection probability. It is important to control the missed detections because they cause collisions with primary transmissions and lead to retransmissions at both the primary and secondary user. The minimization of the number of active sensors is formulated as a binary integer programming problem. Simulations show that the proposed machine learning based sensing policy ...
Oksanen, Jan; Koivunen, Visa
The new amateur radio university network: AMUNET
Science Conference Proceedings (OSTI)
The intention of this paper is to give the readers an opportunity to become familiar with nonofficial and often ad-hoc constructed, computerized amateur radio networks, that might be easily used as AMUNETs - the digital links between university centers, ... Keywords: ADL, AMUNET, amateur radio, communication, computer, education, rural area, university
Miroslav Skoric
Review: Cognitive radio network security: A survey
Science Conference Proceedings (OSTI)
Recent advancements in wireless communication are creating a spectrum shortage problem on a daily basis. Recently, Cognitive Radio (CR), a novel technology, has attempted to minimize this problem by dynamically using the free spectrum in wireless communications ... Keywords: Attacks, Primary users, Radio, Secondary users, Security, Trust
Sazia Parvin; Farookh Khadeer Hussain; Omar Khadeer Hussain; Song Han; Biming Tian; Elizabeth Chang
Radio channel modeling for mobile ad hoc wireless networks .
??The radio channel places fundamental limitations on the performance of mobile ad hoc wireless networks. In the mobile radio environment, fading due to multipath delay� (more)
Sng, Sin Hie
Underground radio technology saves miners and emergency response...
NLE Websites -- All DOE Office Websites (Extended Search)
Underground radio technology saves miners and emergency response personnel Underground radio technology saves miners and emergency response personnel Founded through LANL, Vital...
Security - Identification Badges
Science Conference Proceedings (OSTI)
Security - Identification Badges. All doors to the Child Care Center are locked at all times and access is via the card reader system only. ...
Science Conference Proceedings (OSTI)
The performance of a three-dimensional ionospheric electron density model derived from FormoSat3/COSMIC GPS Radio Occultation measurements, called the TaiWan Ionosphere Model (TWIM), in removing the ionospheric delays in single-frequency pseudorange ... Keywords: Ionospheric delay, Ionospheric model, Single-frequency GPS positioning
Ernest Pagaran Macalalad; Lung-Chih Tsai; Joz Wu; Chao-Han Liu
Science Conference Proceedings (OSTI)
We have searched for prompt radio emission from nine gamma-ray bursts (GRBs) with a 12 m telescope at 1.4 GHz, with a time resolution of 64 {mu}s to 1 s. We detected single dispersed radio pulses with significances >6{sigma} in the few minutes following two GRBs. The dispersion measures of both pulses are well in excess of the expected Galactic values, and the implied rate is incompatible with known sources of single dispersed pulses. The arrival times of both pulses also coincide with breaks in the GRB X-ray light curves. A null trial and statistical arguments rule out random fluctuations as the origin of these pulses with >95% and {approx}97% confidence, respectively, although a simple population argument supports a GRB origin with confidence of only 2%. We caution that we cannot rule out radio frequency interference (RFI) as the origin of these pulses. If the single pulses are not related to the GRBs, we set an upper limit on the flux density of radio pulses emitted between 200 and 1800 s after a GRB of 1.27w {sup -1/2} Jy, where 6.4 Multiplication-Sign 10{sup -5} s 1 s) variations. These limits are some of the most constraining at high time resolution and GHz frequencies in the early stages of the GRB phenomenon.
Bannister, K. W.; Murphy, T.; Gaensler, B. M. [Sydney Institute for Astronomy (SIfA), School of Physics A29, University of Sydney, NSW 2006 (Australia); Reynolds, J. E., E-mail: email@example.com [CSIRO Astronomy and Space Science, P.O. Box 76, Epping, NSW 1710 (Australia)
Science Conference Proceedings (OSTI)
NIST-F1 Cesium Fountain Atomic Clock The Primary Time and Frequency Standard for the United States. NIST-F1, the nation's ...
Science Conference Proceedings (OSTI)
Recent radio observations have identified a class of structures, so-called radio relics, in clusters of galaxies. The radio emission from these sources is interpreted as synchrotron radiation from GeV electrons gyrating in {mu}G-level magnetic fields. Radio relics, located mostly in the outskirts of clusters, seem to associate with shock waves, especially those developed during mergers. In fact, they seem to be good structures to identify and probe such shocks in intracluster media (ICMs), provided we understand the electron acceleration and re-acceleration at those shocks. In this paper, we describe time-dependent simulations for diffusive shock acceleration at weak shocks that are expected to be found in ICMs. Freshly injected as well as pre-existing populations of cosmic-ray (CR) electrons are considered, and energy losses via synchrotron and inverse Compton are included. We then compare the synchrotron flux and spectral distributions estimated from the simulations with those in two well-observed radio relics in CIZA J2242.8+5301 and ZwCl0008.8+5215. Considering that CR electron injection is expected to be rather inefficient at weak shocks with Mach number M {approx}< a few, the existence of radio relics could indicate the pre-existing population of low-energy CR electrons in ICMs. The implication of our results on the merger shock scenario of radio relics is discussed.
Kang, Hyesung [Department of Earth Sciences, Pusan National University, Pusan 609-735 (Korea, Republic of); Ryu, Dongsu [Department of Astronomy and Space Science, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Jones, T. W., E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)
The emission of fundamental and harmonic frequency radio waves of type II radio bursts are assumed to be products of three-wave interaction processes of beam-excited Langmuir waves. Using a particle-in-cell code, we have performed simulations of the assumed emission region, a coronal mass ejection foreshock with two counterstreaming electron beams. Analysis of wavemodes within the simulation shows self-consistent excitation of beam-driven modes, which yield interaction products at both fundamental and harmonic emission frequencies. Through variation of the beam strength, we have investigated the dependence of energy transfer into electrostatic and electromagnetic modes, confirming the quadratic dependence of electromagnetic emission on electron beam strength.
Ganse, Urs; Kilian, Patrick; Spanier, Felix [Lehrstuhl fuer Astronomie, Universitaet Wuerzburg, Wuerzburg (Germany); Vainio, Rami, E-mail: email@example.com [Department of Physics, University of Helsinki, Helsinki (Finland)
Estimating frequency of change
Science Conference Proceedings (OSTI)
Many online data sources are updated autonomously and independently. In this article, we make the case for estimating the change frequency of data to improve Web crawlers, Web caches and to help data mining. We first identify various scenarios, where ... Keywords: Change frequency estimation, Poisson process
Junghoo Cho; Hector Garcia-Molina
Microfabricated ion frequency standard
A microfabricated ion frequency standard (i.e. an ion clock) is disclosed with a permanently-sealed vacuum package containing a source of ytterbium (Yb) ions and an octupole ion trap. The source of Yb ions is a micro-hotplate which generates Yb atoms which are then ionized by a ultraviolet light-emitting diode or a field-emission electron source. The octupole ion trap, which confines the Yb ions, is formed from suspended electrodes on a number of stacked-up substrates. A microwave source excites a ground-state transition frequency of the Yb ions, with a frequency-doubled vertical-external-cavity laser (VECSEL) then exciting the Yb ions up to an excited state to produce fluorescent light which is used to tune the microwave source to the ground-state transition frequency, with the microwave source providing a precise frequency output for the ion clock.
Schwindt, Peter (Albuquerque, NM); Biedermann, Grant (Albuquerque, NM); Blain, Matthew G. (Albuquerque, NM); Stick, Daniel L. (Albuquerque, NM); Serkland, Darwin K. (Albuquerque, NM); Olsson, III, Roy H. (Albuquerque, NM)
'Radio Wave Cooling' Offers New Twist on Laser Cooling
Science Conference Proceedings (OSTI)
'Radio Wave Cooling' Offers New Twist on Laser Cooling. From NIST Tech Beat: September 13, 2007. ...
Acousto-optical correlation spectrometer for radio astronomy
Science Conference Proceedings (OSTI)
The objective of this thesis is to develop and construct a wide-band, high-resolution, two-channel prototype acousto-optic correlation spectrometer (AOCS) to analyze signals received by the three-element millimeter-wave interferometer at Caltech's Owens Valley Radio Observatory (OVRO), which may be used to study the distribution of carbon monoxide and other molecules in galaxies. The proposed correlation spectrometer has the main advantage of large time-bandwidth products and hence of low cost per frequency channel. Thus, it is suitable for many scientific objectives that require both large bandwidth and high resolution, such as mapping the distribution and temperature of the interstellar gases of galactic sources and extragalactic sources or studying the atmospheric conditions of planets in the solar system. Phase switching has been used to reduce the zero level variation of this instrument, and is found to be more effective than other schemes used by the single dish acousto-optical spectrometers. Both the frequency resolution and the frequency coverage of this instrument can be changed easily, and give it a flexibility not attainable by the filter-bank spectrometers.
Cheung, K.
Experimental methodology for non-thermal effects of electromagnetic radiation on biologics
Appropriate equipment is needed for research on the effects of radio-frequency radiation from radio-frequency identification (RF-ID) systems on biological materials. In the present study, a complete test system comprising ...
Cox, Felicia C. A. I
GMRT study of X-shaped radio sources
Context. The nature of X-shaped sources is a matter of considerable debate in the literature: it has even been proposed that they provide evidence for black-hole-mergers/spin-reorientation, and therefore constrain the rate of strong gravitational wave events. Aim. To explore the nature of these X-shaped radio galaxies. Method. We conduct a systematic study of a large sample of known and newly discovered X-shaped sources along with a comparison sample. We used the Giant Metrewave Radio Telescope with resolution of $\\sim6^{\\prime\\prime}$ to $\\sim15^{\\prime\\prime}$ at 610 MHz and 240 MHz in the dual-frequency mode. Preliminary Result. Based on our careful analysis and estimation of the possible systematic errors, the known X-shaped sources divide into the following three categories: (i) the wings have flatter spectral indices than the active lobes, (ii) the wings and the active lobes have comparable spectral indices, and (iii) the wings have steeper spectral indices than the active lobes. In addition, based on our preliminary analysis, one sample source from our comparison sample shows a spectral index result belonging to category (i). Future. Milliarcsecond scale imaging will be conducted on some of these X-shaped sources to investigate if they are examples of binary AGN systems and thereby understand the nature of these sources.
Dharam Vir Lal; A. Pramesh Rao; Martin J. Hardcastle; C. C. Cheung; Sanjay Bhatnagar; Ralph P. Kraft; Andrei P. Lobanov; Anton J. Zensus
GNSS radio occultation constellation observing system experiments
Science Conference Proceedings (OSTI)
Observing system experiments within the operational ECMWF data assimilation framework have been performed for summer 2008 when the largest recorded number of GNSS radio occultation observations from both operational and experimental satellites ...
Peter Bauer; G�bor Radn�ti; Sean Healy; Carla Cardinali
Errors in Radio Acoustic Sounding of Temperature
Science Conference Proceedings (OSTI)
With the use of simultaneous correction for radial wind, the accuracy of radio acoustic sounding systems for the measurement of temperature has been substantially improved. The temperature accuracy can now be affected by a number of factors that ...
Wayne M. Angevine; W. L. Ecklund
Imprint of Intergalactic Shocks on the Radio Sky
Strong intergalactic shocks are a natural consequence of structure formation in the universe. They are expected to deposit large fractions of their energy in relativistic electrons (xi_e~0.05 according to SNR observations) and magnetic fields (xi_B~0.01 according to cluster halo observations). We calculate the synchrotron emission from such shocks using an analytical model, calibrated with a hydrodynamical LCDM simulation. The resulting signal composes a large fraction of the extragalactic radio background (ERB) below 500 MHz. The associated angular fluctuations dominate the sky for frequencies nu3*10^-4. The fluctuating signal is most pronounced for nugas and magnetic fields. Space missions such as ALFA will thus provide important insight into the structure and composition of our Galaxy (abridged).
Uri Keshet; Eli Waxman; Abraham Loeb
Kinetically Dominated FRII Radio Sources
The existence of FR II objects that are kinetically dominated, the jet kinetic luminosity, $Q$, is larger than the total thermal luminosity (IR to X-ray) of the accretion flow, $L_{bol}$, is of profound theoretical interest. Such objects are not expected in most theoretical models of the central engine of radio loud AGN. Thus, establishing such a class of objects is an important diagnostic for filtering through the myriad of theoretical possibilities. This paper attempts to establish a class of quasars that have existed in a state of kinetic dominance, $R(t)\\equiv Q(t)/L_{bol}(t)>1$, at some epoch, $t$. It is argued that the 10 quasars in this article with a long term time average $Q(t)$, $\\bar{Q}$, that exceed $L_{Edd}$ are likely to have satisfied the condition $R(t)>1$ either presently or in the past based on the rarity of $L_{bol}>L_{Edd}$ quasars. Finally, the existence of these sources is discussed in the context of the theory of the central engine.
Brian Punsly
Contemporaneous observations of the radio galaxy NGC 1275 from radio to very high energy gamma-rays
The radio galaxy NGC 1275, recently identified as a very high energy (VHE, >100 GeV) gamma-ray emitter by MAGIC, is one of the few non-blazar AGN detected in the VHE regime. In order to better understand the origin of the gamma-ray emission and locate it within the galaxy, we study contemporaneous multi-frequency observations of NGC 1275 and model the overall spectral energy distribution (SED). We analyze unpublished MAGIC observations carried out between Oct. 2009 and Feb. 2010, and the already published ones taken between Aug. 2010 and Feb. 2011. We study the multi-band variability and correlations analyzing data of Fermi-LAT (0.1 - 100 GeV), Chandra (X-ray), KVA (optical) and MOJAVE (radio) taken during the same period. Using custom Monte Carlo simulations corresponding to early MAGIC stereo data, we detect NGC 1275 also in the earlier MAGIC campaign. The flux level and energy spectra are similar to the results of the second campaign. The monthly light curve above 100 GeV shows a hint of variability at the...
Aleksi?, J; Antonelli, L A; Antoranz, P; Babic, A; Bangale, P; de Almeida, U Barres; Barrio, J A; Gonz�lez, J Becerra; Bednarek, W; Berger, K; Bernardini, E; Biland, A; Blanch, O; Bock, R K; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T; Carmona, E; Carosi, A; Fidalgo, D Carreto; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Covino, S; Da Vela, P; Dazzi, F; De Angelis, A; De Caneva, G; De Lotto, B; Mendez, C Delgado; Doert, M; Dom�nguez, A; Prester, D Dominis; Dorner, D; Doro, M; Einecke, S; Eisenacher, D; Elsaesser, D; Farina, E; Ferenc, D; Fonseca, M V; Font, L; Frantzen, K; Fruck, C; L�pez, R J Garc�a; Garczarczyk, M; Terrats, D Garrido; Gaug, M; Giavitto, G; Godinovi?, N; Mu�oz, A Gonz�lez; Gozzini, S R; Hadamek, A; Hadasch, D; Herrero, A; Hildebrand, D; Hose, J; Hrupec, D; Idec, W; Kadenius, V; Kellermann, H; Knoetig, M L; Krause, J; Kushida, J; La Barbera, A; Lelas, D; Lewandowska, N; Lindfors, E; Lombardi, S; L�pez, M; L�pez-Coto, R; L�pez-Oramas, A; Lorenz, E; Lozano, I; Makariev, M; Mallot, K; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Mart�nez, M; Mazin, D; Menzel, U; Meucci, M; Miranda, J M; Mirzoyan, R; Moralejo, A; Munar-Adrover, P; Nakajima, D; Niedzwiecki, A; Nilsson, K; Nowak, N; Orito, R; Overkemping, A; Paiano, S; Palatiello, M; Paneque, D; Paoletti, R; Paredes, J M; Paredes-Fortuny, X; Partini, S; Persic, M; Prada, F; Moroni, P G Prada; Prandini, E; Preziuso, S; Puljak, I; Reinthal, R; Rhode, W; Rib�, M; Rico, J; Garcia, J Rodriguez; R�gamer, S; Saggion, A; Saito, K; Salvati, M; Satalecka, K; Scalzotto, V; Scapin, V; Schultz, C; Schweizer, T; Shore, S N; Sillanp��, A; Sitarek, J; Snidaric, I; Sobczynska, D; Spanier, F; Stamatescu, V; Stamerra, A; Steinbring, T; Storz, J; Sun, S; Suri?, T; Takalo, L; Tavecchio, F; Temnikov, P; Terzi?, T; Tescaro, D; Teshima, M; Thaele, J; Tibolla, O; Torres, D F; Toyama, T; Treves, A; Uellenbeck, M; Vogler, P; Wagner, R M; Zandanel, F; Zanin, R; Balmaverde, B; Kataoka, J; Rekola, R; Takahashi, Y; .,
Impedance Noise Identification for State-of-Health Prognostics
Impedance Noise Identification is an in-situ method of measuring battery impedance as a function of frequency using a random small signal noise excitation source. Through a series of auto- and cross-correlations and Fast Fourier Transforms, the battery complex impedance as a function of frequency can be determined. The results are similar to those measured under a lab-scale electrochemical impedance spectroscopy measurement. The lab-scale measurements have been shown to correlate well with resistance and power data that are typically used to ascertain the remaining life of a battery. To this end, the Impedance Noise Identification system is designed to acquire the same type of data as an on-board tool. A prototype system is now under development, and results are being compared to standardized measurement techniques such as electrochemical impedance spectroscopy. A brief description of the Impedance Noise Identification hardware system and representative test results are presented.
Jon P. Christophersen; Chester G. Motloch; John L. Morrison; Ian B. Donnellan; William H. Morrison
Comparing LOPES measurements of air-shower radio emission with REAS 3.11 and CoREAS simulations
Cosmic ray air showers emit radio pulses at MHz frequencies, which can be measured with radio antenna arrays - like LOPES at the Karlsruhe Institute of Technology in Germany. To improve the understanding of the radio emission, we test theoretical descriptions with measured data. The observables used for these tests are the absolute amplitude of the radio signal, and the shape of the radio lateral distribution. We compare lateral distributions of more than 500 LOPES events with two recent and public Monte Carlo simulation codes, REAS 3.11 and CoREAS (v 1.0). The absolute radio amplitudes predicted by REAS 3.11 are in good agreement with the LOPES measurements. The amplitudes predicted by CoREAS are lower by a factor of two, and marginally compatible with the LOPES measurements within the systematic scale uncertainties. In contrast to any previous versions of REAS, REAS 3.11 and CoREAS now reproduce the shape of the measured lateral distributions correctly. This reflects a remarkable progress compared to the si...
Apel, W D; B�hren, L; Bekk, K; Bertaina, M; Biermann, P L; Bl�mer, J; Bozdog, H; Brancus, I M; Chiavassa, A; Daumiller, K; de Souza, V; Di Pierro, F; Doll, P; Engel, R; Falcke, H; Fuchs, B; Fuhrmann, D; Gemmeke, H; Grupen, C; Haungs, A; Heck, D; H�randel, J R; Horneffer, A; Huber, D; Huege, T; Isar, P G; Kampert, K -H; Kang, D; Kr�mer, O; Kuijpers, J; Link, K; Luczak, P; Ludwig, M; Mathes, H J; Melissas, M; Morello, C; Oehlschl�ger, J; Palmieri, N; Pierog, T; Rautenberg, J; Rebel, H; Roth, M; R�hle, C; Saftoiu, A; Schieler, H; Schmidt, A; Schr�der, F G; Sima, O; Toma, G; Trinchero, G C; Weindl, A; Wochele, J; Zabierowski, J; Zensus, J A
Graphene Frequency Multipliers
In this letter, the ambipolar transport properties of graphene flakes have been used to fabricate full-wave signal rectifiers and frequency-doubling devices. By correctly biasing an ambipolar graphene field-effect transistor ...
Wang, Han
High frequency breakdown voltage
This report contains information about the effect of frequency on the breakdown voltage of an air gap at standard pressure and temperature, 76 mm Hg and O{degrees}C, respectively. The frequencies of interest are 47 MHz and 60 MHz. Additionally, the breakdown in vacuum is briefly considered. The breakdown mechanism is explained on the basis of collision and ionization. The presence of the positive ions produced by ionization enhances the field in the gap, and thus determines the breakdown. When a low-frequency voltage is applied across the gap, the breakdown mechanism is the same as that caused by the DC or static voltage. However, when the frequency exceeds the first critical value f{sub c}, the positive ions are trapped in the gap, increasing the field considerably. This makes the breakdown occur earlier; in other words, the breakdown voltage is lowered. As the frequency increases two decades or more, the second critical frequency, f{sub ce}, is reached. This time the electrons start being trapped in the gap. Those electrons that travel multiple times across the gap before reaching the positive electrode result in an enormous number of electrons and positive ions being present in the gap. The result is a further decrease of the breakdown voltage. However, increasing the frequency does not decrease the breakdown voltage correspondingly. In fact, the associated breakdown field intensity is almost constant (about 29 kV/cm).The reason is that the recombination rate increases and counterbalances the production rate, thus reducing the effect of the positive ions` concentration in the gap. The theory of collision and ionization does not apply to the breakdown in vacuum. It seems that the breakdown in vacuum is primarily determined by the irregularities on the surfaces of the electrodes. Therefore, the effect of frequency on the breakdown, if any, is of secondary importance.
Chu, Thanh Duy
Science Conference Proceedings (OSTI)
This paper presents a search for radio transients at a frequency of 73.8 MHz (4 m wavelength) using the all-sky imaging capabilities of the Long Wavelength Demonstrator Array (LWDA). The LWDA was a 16-dipole phased array telescope, located on the site of the Very Large Array in New Mexico. The field of view of the individual dipoles was essentially the entire sky, and the number of dipoles was sufficiently small that a simple software correlator could be used to make all-sky images. From 2006 October to 2007 February, we conducted an all-sky transient search program, acquiring a total of 106 hr of data; the time sampling varied, being 5 minutes at the start of the program and improving to 2 minutes by the end of the program. We were able to detect solar flares, and in a special-purpose mode, radio reflections from ionized meteor trails during the 2006 Leonid meteor shower. We detected no transients originating outside of the solar system above a flux density limit of 500 Jy, equivalent to a limit of no more than about 10{sup -2} events yr{sup -1} deg{sup -2}, having a pulse energy density {approx}>1.5 x 10{sup -20} J m{sup -2} Hz{sup -1} at 73.8 MHz for pulse widths of about 300 s. This event rate is comparable to that determined from previous all-sky transient searches, but at a lower frequency than most previous all-sky searches. We believe that the LWDA illustrates how an all-sky imaging mode could be a useful operational model for low-frequency instruments such as the Low Frequency Array, the Long Wavelength Array station, the low-frequency component of the Square Kilometre Array, and potentially the Lunar Radio Array.
Lazio, T. Joseph W.; Clarke, Tracy E.; Lane, W. M.; Gross, C.; Kassim, N. E.; Hicks, B.; Polisensky, E.; Stewart, K. [Remote Sensing Division, Naval Research Laboratory, 4555 Overlook Ave., SW, Washington, DC 20375 (United States); Ray, P. S. [Space Science Division, Naval Research Laboratory, 4555 Overlook Ave., SW, Washington, DC 20375-5382 (United States); Wood, D. [Praxis, Inc., 5845 Richmond Highway, Suite 700, Alexandria, VA 22303 (United States); York, J. A.; Kerkhoff, A. [Applied Research Laboratories, University of Texas at Austin, P.O. Box 8029, Austin, TX 78713-8029 (United States); Dalal, N. Paravastu [American Society for Engineering Education, Washington, DC 20036 (United States); Cohen, A. S. [Johns Hopkins University, Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Erickson, W. C., E-mail: firstname.lastname@example.com [School of Mathematics and Science, University of Tasmania, Churchill Ave., Sandy Bay, Tasmania 7005 (Australia)
Science Conference Proceedings (OSTI)
Identification and analysis of temporal trends and low-frequency variability in discrete time series is an important practical topic in the understanding and prediction of many atmospheric processes, for example, in analysis of climate change. ...
Illia Horenko
Interplanetary shocks lacking type II radio bursts
We report on the radio-emission characteristics of 222 interplanetary (IP) shocks. A surprisingly large fraction of the IP shocks (~34%) is radio quiet (i.e., the shocks lacked type II radio bursts). The CMEs associated with the RQ shocks are generally slow (average speed ~535 km/s) and only ~40% of the CMEs were halos. The corresponding numbers for CMEs associated with radio loud (RL) shocks are 1237 km/s and 72%, respectively. The RQ shocks are also accompanied by lower peak soft X-ray flux. CMEs associated with RQ (RL) shocks are generally accelerating (decelerating). The kinematics of CMEs associated with the km type II bursts is similar to those of RQ shocks, except that the former are slightly more energetic. Comparison of the shock The RQ shocks seem to be mostly subcritical and quasi-perpendicular. The radio-quietness is predominant in the rise phase and decreases through the maximum and declining phases of solar cycle 23. The solar sources of the shock-driving CMEs follow the sunspot butterfly diagra...
Gopalswamy, N; Makela, P; Akiyama, S; Yashiro, S; Kaiser, M L; Howard, R A; Bougeret, J -L
Java-Applet For Radio Spectra Analysis
New services for Clusters of Galaxies Database created in the Astronomical Institute of SPbU have been constructed. The detailed description of database and its content is available at http://www.astro.spbu.ru/CLUSTERS/. The information contained in the database can be used for solution of the specific astronomical problems. One of these problems is the researches of radio emission spectra of clusters' objects. The researches can give help in solution of the problems of origin and evolution of extragalactic radio sources. Spectra of radio galaxies contain important information about radio power in the processes responsible for their activity. This report presents the software for the database that provides work with radio spectra of extragalactic sources. This client-application has been released as the Java-applet and thus provides a Web based interface that is supported on many operating systems. The facilities of the applet such as approximations of spectra measurement points and calculation of spectral parameters are illustrated in the report. Also we demonstrate new version of the application that realized on Java2 and gave access to additional functions such as printing.
A. S. Trushkina; A. G. Gubanov
Science Conference Proceedings (OSTI)
The double pulsar PSR J0737-3039A/B displays short, 30 s eclipses that arise around conjunction when the radio waves emitted by pulsar A are absorbed as they propagate through the magnetosphere of its companion pulsar B. These eclipses offer a unique opportunity to directly probe the magnetospheric structure and the plasma properties of pulsar B. We have performed a comprehensive analysis of the eclipse phenomenology using multi-frequency radio observations obtained with the Green Bank Telescope. We have characterized the periodic flux modulations previously discovered at 820 MHz by McLaughlin et al. and investigated the radio frequency dependence of the duration and depth of the eclipses. Based on their weak radio frequency evolution, we conclude that the plasma in pulsar B's magnetosphere requires a large multiplicity factor ({approx}10{sup 5}). We also found that, as expected, flux modulations are present at all radio frequencies in which eclipses can be detected. Their complex behavior is consistent with the confinement of the absorbing plasma in the dipolar magnetic field of pulsar B as suggested by Lyutikov and Thompson and such a geometric connection explains that the observed periodicity is harmonically related to pulsar B's spin frequency. We observe that the eclipses require a sharp transition region beyond which the plasma density drops off abruptly. Such a region defines a plasmasphere that would be well inside the magnetospheric boundary of an undisturbed pulsar. It is also two times smaller than the expected standoff radius calculated using the balance of the wind pressure from pulsar A and the nominally estimated magnetic pressure of pulsar B.
Breton, R. P. [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada); Kaspi, V. M. [Department of Physics, McGill University, Montreal, QC H3A 2T8 (Canada); McLaughlin, M. A. [Department of Physics, West Virginia University, Morgantown, WV 26506 (United States); Lyutikov, M. [Department of Physics, Purdue University, West Lafayette, IN 47907 (United States); Kramer, M. [Max Planck Institut fuer Radioastronomie, Auf dem Huegel 69, 53121 Bonn (Germany); Stairs, I. H. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada); Ransom, S. M. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Ferdman, R. D. [University of Manchester, Jodrell Bank Centre for Astrophysics, Alan Turing Building, Manchester, M13 9PL (United Kingdom); Camilo, F. [Columbia University, New York, NY 10027 (United States); Possenti, A., E-mail: email@example.com [INAF-Osservatorio Astronomico di Cagliari, Poggio dei Pini, strada 54, I-09012 Capoterra (Italy)
A GMRT multifrequency radio study of the isothermal core of the poor galaxy cluster AWM 4
We present a detailed radio morphological study and spectral analysis of the wide-angle-tail radio source 4C +24.36 associated with the dominant galaxy in the relaxed galaxy cluster AWM 4. Our study is based on new high sensitivity GMRT observations at 235 MHz, 327 MHz and 610 MHz, and on literature and archival data at other frequencies. We find that the source major axis is likely oriented at a small angle with respect to the plane of the sky. The wide-angle-tail morphology can be reasonably explained by adopting a simple hydrodynamical model in which both ram pressure (driven by the motion of the host galaxy) and buoyancy forces contribute to bend the radio structure. The spectral index progressively steepens along the source major axis from $\\alpha \\sim$0.3 in the region close to the radio nucleus to beyond 1.5 in the lobes. The results of the analysis of the spectral index image allow us to derive an estimate of the radiative age of the source of $\\sim$ 160 Myr. The cluster X-ray emitting gas has a relax...
Giacintucci, S; Murgia, M; Raychaudhuri, S; O'Sullivan, E J; Venturi, T; David, L P; Mazzotta, P; Clarke, T E; Athreya, R M
Survey on solar X-ray flares and associated coherent radio emissions
The radio emission during 201 X-ray selected solar flares was surveyed from 100 MHz to 4 GHz with the Phoenix-2 spectrometer of ETH Zurich. The selection includes all RHESSI flares larger than C5.0 jointly observed from launch until June 30, 2003. Detailed association rates of radio emission during X-ray flares are reported. In the decimeter wavelength range, type III bursts and the genuinely decimetric emissions (pulsations, continua, and narrowband spikes) were found equally frequently. Both occur predominantly in the peak phase of hard X-ray (HXR) emission, but are less in tune with HXRs than the high-frequency continuum exceeding 4 GHz, attributed to gyrosynchrotron radiation. In 10% of the HXR flares, an intense radiation of the above genuine decimetric types followed in the decay phase or later. Classic meter-wave type III bursts are associated in 33% of all HXR flares, but only in 4% they are the exclusive radio emission. Noise storms were the only radio emission in 5% of the HXR flares, some of them w...
Benz, A O; Csillagy, A; Saint-Hilaire, P; Benz, Arnold O.; Grigis, Paolo; Csillagy, Andre; Saint-Hilaire, Pascal
In recent studies, we proposed that source properties of type II radio bursts can be inferred through a causal relationship between the special shape of the type II dynamic spectrum (e.g., bump or break) and simultaneous extreme ultraviolet (EUV)/white light imaging observations (e.g., CME-shock crossing streamer structures). As a further extension of these studies, in this paper we examine the coronal mass ejection (CME) event on 2007 December 31 associated with a multiple type II radio burst. We identify the presence of two spectral bump features on the observed dynamic spectrum. By combining observational analyses of the radio spectral observations and the EUV-white light imaging data, we conclude that the two spectral bumps result from a CME-shock propagating across dense streamers on the southern and northern sides of the CME. It is inferred that the corresponding two type II emissions originate separately from the two CME-shock flanks where the shock geometries are likely quasi-perpendicular or oblique. Since the emission lanes are bumped as a whole within a relatively short time, it suggests that the type II radio bursts with bumps of this study are emitted from spatially confined sources (with a projected lateral dimension smaller than 0.05-0.1 R{sub Sun} at a fundamental frequency level of 20-30 MHz).
Feng, S. W.; Chen, Y.; Kong, X. L.; Li, G.; Song, H. Q. [Institute of Space Sciences and School of Space Science and Physics, Shandong University, Weihai 264209 (China)] [Institute of Space Sciences and School of Space Science and Physics, Shandong University, Weihai 264209 (China); Feng, X. S. [SIGMA Weather Group, State Key laboratory for Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190 (China)] [SIGMA Weather Group, State Key laboratory for Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190 (China); Guo, Fan, E-mail: firstname.lastname@example.com [Department of Planetary Sciences and Lunar and Planetary laboratory, University of Arizona, Tucson, AZ 85721 (United States)] [Department of Planetary Sciences and Lunar and Planetary laboratory, University of Arizona, Tucson, AZ 85721 (United States)
An adaptive location estimator using tracking algorithms for indoor WLANs
Science Conference Proceedings (OSTI)
This paper presents adaptive algorithms for estimating the location of a mobile terminal (MT) based on radio propagation modeling (RPM), Kalman filtering (KF), and radio-frequency identification (RFID) assisting for indoor wireless local area networks ... Keywords: Calibration, Kalman filtering, Location estimation, Neural network, Radio-frequency identification, Tracking, Wireless local area network
Yih-Shyh Chiou; Chin-Liang Wang; Sheng-Cheng Yeh
Radio Towers Geothermal Area | Open Energy Information
Radio Towers Geothermal Area Radio Towers Geothermal Area Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Geothermal Resource Area: Radio Towers Geothermal Area Contents 1 Area Overview 2 History and Infrastructure 3 Regulatory and Environmental Issues 4 Exploration History 5 Well Field Description 6 Geology of the Area 7 Geofluid Geochemistry 8 NEPA-Related Analyses (0) 9 Exploration Activities (0) 10 References Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"TERRAIN","zoom":6,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"500px","height":"300px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":43.03666667,"lon":-115.4566667,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}
Dual-etalon, cavity-ring-down, frequency comb spectroscopy.
Science Conference Proceedings (OSTI)
The 'dual etalon frequency comb spectrometer' is a novel low cost spectometer with limited moving parts. A broad band light source (pulsed laser, LED, lamp ...) is split into two beam paths. One travels through an etalon and a sample gas, while the second arm is just an etalon cavity, and the two beams are recombined onto a single detector. If the free spectral ranges (FSR) of the two cavities are not identical, the intensity pattern at the detector with consist of a series of heterodyne frequencies. Each mode out of the sample arm etalon with have a unique frequency in RF (radio-frequency) range, where modern electronics can easily record the signals. By monitoring these RF beat frequencies we can then determine when an optical frequencies is absorbed. The resolution is set by the FSR of the cavity, typically 10 MHz, with a bandwidth up to 100s of cm{sup -1}. In this report, the new spectrometer is described in detail and demonstration experiments on Iodine absorption are carried out. Further we discuss powerful potential next generation steps to developing this into a point sensor for monitoring combustion by-products, environmental pollutants, and warfare agents.
Strecker, Kevin E.; Chandler, David W.
Why inverse document frequency?
Science Conference Proceedings (OSTI)
Inverse Document Frequency (IDF) is a popular measure of a word's importance. The IDF invariably appears in a host of heuristic measures used in information retrieval. However, so far the IDF has itself been a heuristic. In this paper, we show IDF to ...
Kishore Papineni
Science Conference Proceedings (OSTI)
We revisit the concept of a blazar sequence that relates the synchrotron peak frequency ({nu}{sub peak}) in blazars with synchrotron peak luminosity (L{sub peak}, in {nu}L{sub {nu}}) using a large sample of radio-loud active galactic nuclei. We present observational evidence that the blazar sequence is formed from two populations in the synchrotron {nu}{sub peak}-L{sub peak} plane, each forming an upper edge to an envelope of progressively misaligned blazars, and connecting to an adjacent group of radio galaxies having jets viewed at much larger angles to the line of sight. When binned by jet kinetic power (L{sub kin}; as measured through a scaling relationship with extended radio power), we find that radio core dominance decreases with decreasing synchrotron L{sub peak}, revealing that sources in the envelope are generally more misaligned. We find population-based evidence of velocity gradients in jets at low kinetic powers ({approx}10{sup 42}-10{sup 44.5} erg s{sup -1}), corresponding to Fanaroff-Riley (FR) I radio galaxies and most BL Lac objects. These low jet power 'weak-jet' sources, thought to exhibit radiatively inefficient accretion, are distinguished from the population of non-decelerating, low synchrotron-peaking (LSP) blazars and FR II radio galaxies ('strong' jets) which are thought to exhibit radiatively efficient accretion. The two-population interpretation explains the apparent contradiction of the existence of highly core-dominated, low-power blazars at both low and high synchrotron peak frequencies, and further implies that most intermediate synchrotron peak sources are not intermediate in intrinsic jet power between LSP and high synchrotron-peaking (HSP) sources, but are more misaligned versions of HSP sources with similar jet powers.
Meyer, Eileen T.; Fossati, Giovanni [Department of Physics and Astronomy, Rice University, Houston, TX 77005 (United States); Georganopoulos, Markos [Department of Physics, University of Maryland Baltimore County, Baltimore, MD 21250 (United States); Lister, Matthew L., E-mail: firstname.lastname@example.com [Department of Physics, Purdue University, West Lafayette, IN 47907 (United States)
Impulse Radio Ultra-Wideband Communication Over Free-Space Optical Links
A composite impulse radio ultra-wideband (IR-UWB) communication system is presented. The proposed system model aims to transmit UWB pulses over several kilometers through free-space optical (FSO) links and depending on the link design, the electrical estimates of the FSO system can be directly used or distributed to end-user through radio-frequency (RF) links over short ranges. However, inhomogeneities on the FSO transmission path cause random fluctuations in the received signal intensity and these effects induced by atmospheric turbulence closely effect the system performance. Several distinct probability distributions based on experimental measurements are used to characterize FSO channels and using these probabilistic models, detection error probability analysis of the proposed system for different link designs are carried out under weak, moderate and strong turbulence conditions. The results of the analysis show that depending on the atmospheric conditions, system performance of the composite link can hav...
Davaslioglu, Kemal
Maximizing available spectrum for cognitive radios
located primary transmitter/receiver, FDD mode If the systemis Frequency Division Duplexed (FDD) (the two transmitter-
Mishra, Shridhar Mubaraq
Large Radio Astronomy: next 70 Years Step
Some attempts to predict the very distant future of Radio Astronomy are given. It is not easy to predict a list of the first priority problems which may appear, but the facilities potential is more predictable. It is suggested, that in addition to the "dedicated for Radio Astronomy", facilities may be extended greatly by integration with the next generation living standards facilities, connected with People-to-People communications through the global networks and by incorporating of the "Natural facilities", such as grav. lensing, maser amplification in the ISM etc. As an examples of the extreme cases of the $10^9 m^2$ class of the new generation Radio Telescopes, utilization of the personal dipole size communication facilities by SKA type instrument, and array from the asteroids first "Frehnel zones" will be mentioned. Radio Astronomy from the secondary to optical facilities tool will be the only tool in the exploration of the $z>10$ Universe. The reality of all predictions depend mostly on the way, the Civilization will prefer : "Ahead, to HOMO SAPIENCE" or "BACK TO PRIMATES".
Yu. N. Parijskij
Molecular gas in nearby elliptical radio galaxies
Powerful radio-AGN are hosted by massive elliptical galaxies which are usually very poor in molecular gas. Nevertheless the central Black Hole (BH) needs molecular gas for the nuclear activity. Thus it is important to study the origin, the distribution and the kinematics of the molecular gas in such objects. We have performed at the IRAM-30m telescope a survey of the CO(1-0) and CO(2-1) emission in the most powerful radio galaxies of the Local Universe, selected only on the basis of their radio continuum fluxes. The main result of that survey is the low content in molecular gas of such galaxies compared to Seyfert galaxies. The median value of the molecular gas mass is 4x10^8 Msun. Moreover, the CO spectra indicate the presence of a central molecular gas disk in some of these radio galaxies. We complemented this survey with photometric data of SPITZER and IRAS fluxes with the purpose to study the dust and its relation with the molecular gas and AGN.
B. Ocana-Flaquer; S. Leon; J. Lim; F. Combes; Dinh-V-Trung
Molecular gas in nearby elliptical radio galaxies
Powerful radio-AGN are hosted by massive elliptical galaxies which are usually very poor in molecular gas. Nevertheless the central Black Hole (BH) needs molecular gas for the nuclear activity. Thus it is important to study the origin, the distribution and the kinematics of the molecular gas in such objects. We have performed at the IRAM-30m telescope a survey of the CO(1-0) and CO(2-1) emission in the most powerful radio galaxies of the Local Universe, selected only on the basis of their radio continuum fluxes. The main result of that survey is the low content in molecular gas of such galaxies compared to Seyfert galaxies. The median value of the molecular gas mass is 4x10^8 Msun. Moreover, the CO spectra indicate the presence of a central molecular gas disk in some of these radio galaxies. We complemented this survey with photometric data of SPITZER and IRAS fluxes with the purpose to study the dust and its relation with the molecular gas and AGN.
Ocana-Flaquer, B; Lim, J; Combes, F; Dinh-V-Trung,
FM radio: family interplay with sonic mementos
Science Conference Proceedings (OSTI)
Digital mementos are increasingly problematic, as people acquire large amounts of digital belongings that are hard to access and often forgotten. Based on fieldwork with 10 families, we designed a new type of embodied digital memento, the FM Radio. It ... Keywords: audio, mementos, memories, narrative, tangible interaction.
Daniela Petrelli; Nicolas Villar; Vaiva Kalnikaite; Lina Dib; Steve Whittaker
Rapidly Deployable Radio Networks Network Architecture
Quality Radio Link Setup and Control Figure 2: Remote Node Components. 2 #12;passing the cells of handling failure of the master node versus maintaining a hot backup for the master node is to be studied & SEND NEWSWITCH PACKET NODES HANDLE REMOTE Figure 14: State Diagram for Master. START PACKET NEWSWITCH
Bush, Stephen F.
Cosmological Parameters and Quintessence From Radio Galaxies
FRIIb radio galaxies provide a tool to determine the coordinate distance to sources at redshifts from zero to two. The coordinate distance depends on the present values of global cosmological parameters, quintessence, and the equation of state of quintessence. The coordinate distance provides one of the cleanest determinations of global cosmological parameters because it does not depend on the clustering properties of any of the mass-energy components present in the universe. Two complementary methods that provide direct determinations of the coordinate distance to sources with redshifts out to one or two are the modified standard yardstick method utilizing FRIIb radio galaxies, and the modified standard candle method utilizing type Ia supernovae. These two methods are compared here, and are found to be complementary in many ways. The two methods do differ in some regards; perhaps the most significant difference is that the radio galaxy method is completely independent of the local distance scale and independent of the properties of local sources, while the supernovae method is very closely tied to the local distance scale and the properties of local sources. FRIIb radio galaxies provide one of the very few reliable probes of the coordinate distance to sources with redshifts out to two. This method indicates that the current value of the density parameter in non-relativistic matter, ?m, must be low, irrespective of whether the universe is spatially flat, and of whether a significant cosmological constant or quintessence pervades the universe at the present epoch. The effect of quintessence, with equation of state w, is considered. FRIIb radio galaxies indicate that the universe is currently accelerating in its expansion if the primary components of the universe at the present epoch are non-relativistic matter and quintessence, and the universe is spatially flat. 1.
A. Daly; Erick J. Guerra
The large scale clustering of radio sources
The observed two-point angular correlation function, w(theta), of mJy radio sources exhibits the puzzling feature of a power-law behaviour up to very large (almost 10 degrees) angular scales which cannot be accounted for in the standard hierarchical clustering scenario for any realistic redshift distribution of such sources. After having discarded the possibility that the signal can be explained by a high density local source population, we find no alternatives to assuming that - at variance with all the other extragalactic populations studied so far, and in particular with optically selected quasars - radio sources responsible for the large-scale clustering signal were increasingly less clustered with increasing look-back time, up to at least z=1. The data are accurately accounted for in terms of a bias function which decreases with increasing redshift, mirroring the evolution with cosmic time of the characteristic halo mass, M_{star}, entering the non linear regime. In the framework of the `concordance cosmology', the effective halo mass controlling the bias parameter is found to decrease from about 10^{15} M_{sun}/h at z=0 to the value appropriate for optically selected quasars, 10^{13} M_{sun}/h, at z=1.5. This suggests that, in the redshift range probed by the data, the clustering evolution of radio sources is ruled by the growth of large-scale structure, and that they are associated with the densest environments virializing at any cosmic epoch. The data provide only loose constraints on radio source clustering at z>1 so we cannot rule out the possibility that at these redshifts the clustering evolution of radio sources enters a different regime, perhaps similar to that found for optically selected quasars. The dependence of w(theta) on cosmological parameters is also discussed.
M. Negrello; M. Magliocchetti; G. De Zotti
On the Brightness and Waiting-time Distributions of a Type III Radio Storm observed by STEREO/WAVES
Type III solar radio storms, observed at frequencies below approximately 16 MHz by space borne radio experiments, correspond to the quasi-continuous, bursty emission of electron beams onto open field lines above active regions. The mechanisms by which a storm can persist in some cases for more than a solar rotation whilst exhibiting considerable radio activity are poorly understood. To address this issue, the statistical properties of a type III storm observed by the STEREO/WAVES radio experiment are presented, examining both the brightness distribution and (for the first time) the waiting-time distribution. Single power law behavior is observed in the number distribution as a function of brightness; the power law index is approximately 2.1 and is largely independent of frequency. The waiting-time distribution is found to be consistent with a piecewise-constant Poisson process. This indicates that during the storm individual type III bursts occur independently and suggests that the storm dynamics are consiste...
Eastwood, J P; Hudson, H S; Krucker, S; Bale, S D; Maksimovic, M; Goetz, K; Bougeret, J -L
Type III solar radio storms, observed at frequencies below {approx}16 MHz by space-borne radio experiments, correspond to the quasi-continuous, bursty emission of electron beams onto open field lines above active regions. The mechanisms by which a storm can persist in some cases for more than a solar rotation whilst exhibiting considerable radio activity are poorly understood. To address this issue, the statistical properties of a type III storm observed by the STEREO/WAVES radio experiment are presented, examining both the brightness distribution and (for the first time) the waiting-time distribution (WTD). Single power-law behavior is observed in the number distribution as a function of brightness; the power-law index is {approx}2.1 and is largely independent of frequency. The WTD is found to be consistent with a piecewise-constant Poisson process. This indicates that during the storm individual type III bursts occur independently and suggests that the storm dynamics are consistent with avalanche-type behavior in the underlying active region.
Eastwood, J. P.; Hudson, H. S.; Krucker, S.; Bale, S. D. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Wheatland, M. S. [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia); Maksimovic, M.; Bougeret, J.-L. [LESIA, Observatoire de Paris, F-92195 Meudon (France); Goetz, K. [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)], E-mail: email@example.com
High frequency reference electrode
A high frequency reference electrode for electrochemical experiments comprises a mercury-calomel or silver-silver chloride reference electrode with a layer of platinum around it and a layer of a chemically and electrically resistant material such as TEFLON around the platinum covering all but a small ring or halo'' at the tip of the reference electrode, adjacent to the active portion of the reference electrode. The voltage output of the platinum layer, which serves as a redox electrode, and that of the reference electrode are coupled by a capacitor or a set of capacitors and the coupled output transmitted to a standard laboratory potentiostat. The platinum may be applied by thermal decomposition to the surface of the reference electrode. The electrode provides superior high-frequency response over conventional electrodes.
Kronberg, J.W.
High frequency reference electrode
A high frequency reference electrode for electrochemical experiments comprises a mercury-calomel or silver-silver chloride reference electrode with a layer of platinum around it and a layer of a chemically and electrically resistant material such as TEFLON around the platinum covering all but a small ring or halo' at the tip of the reference electrode, adjacent to the active portion of the reference electrode. The voltage output of the platinum layer, which serves as a redox electrode, and that of the reference electrode are coupled by a capacitor or a set of capacitors and the coupled output transmitted to a standard laboratory potentiostat. The platinum may be applied by thermal decomposition to the surface of the reference electrode. The electrode provides superior high-frequency response over conventional electrodes. 4 figs.
Kronberg, J.W.
High frequency reference electrode
A high frequency reference electrode for electrochemical experiments comprises a mercury-calomel or silver-silver chloride reference electrode with a layer of platinum around it and a layer of a chemically and electrically resistant material such as TEFLON around the platinum covering all but a small ring or "halo" at the tip of the reference electrode, adjacent to the active portion of the reference electrode. The voltage output of the platinum layer, which serves as a redox electrode, and that of the reference electrode are coupled by a capacitor or a set of capacitors and the coupled output transmitted to a standard laboratory potentiostat. The platinum may be applied by thermal decomposition to the surface of the reference electrode. The electrode provides superior high-frequency response over conventional electrodes.
Kronberg, James W. (Aiken, SC)
Two-dimensional numerical modeling of Radio-Frequency ion engine discharge
Small satellites are gaining popularity in the space industry and reduction in spacecraft size requires scaling down its propulsion system. Low-power electric propulsion poses a unique challenge due to various scaling ...
Tsay, Michael Meng-Tsuan
c: 0.04 0.3% for 30 m Q) ""C -e. Meters Figure 3 "C ttl Ic: ttl Q) "C -e- Meters Figure 4 FEl amplifier L- lCl "T1 c
Kuenning, R.W.
??Ultrasonic additive manufacturing (UAM) is a low temperature, solid-state manufacturing process that enables the creation of layered solid metal structures with designed anisotropies and embedded� (more)
Wolcott, Paul Joseph
We report on the first detailed analysis of large three dimensional (3D) complex plasma structures in experiments performed in pure rf and combined rf+dc discharge modes. Inductively coupled plasma (ICP) is generated by an rf coil wrapped around the vertically positioned cylindrical glass tube at a pressure of 0.3 mbar. In addition, dc plasma can be generated by applying voltage to the electrodes at the ends of the tube far from the rf coil. The injected monodisperse particles are levitated in the plasma below the coil. A scanning laser sheet and a high resolution camera are used to determine the 3D positions of about $10^5$ particles. The observed bowl-shaped particle clouds reveal coexistence of various structures, including well-distinguished solid-like, less ordered liquid-like, and pronounced string-like phases. New criteria to identify string-like structures are proposed.
S. Mitic; B. A. Klumov; S. A. Khrapak; G. E. Morfill
Origin of stress in radio frequency magnetron sputtered zinc oxide thin films
Highly c-axis oriented ZnO thin films have been deposited on silicon substrates by planar rf magnetron sputtering under varying pressure (10-50 mTorr) and oxygen percentage (50-100%) in the reactive gas (Ar + O{sub 2}) mixture. The as-grown films were found to be stressed over a wide range from -1 x 10{sup 11} to -2 x 10{sup 8} dyne/cm{sup 2} that in turn depends strongly on the processing conditions, and the film becomes stress free at a unique combination of sputtering pressure and reactive gas composition. Raman spectroscopy and photoluminescence (PL) analyses identified the origin of stress as lattice distortion due to defects introduced in the ZnO thin film. FTIR study reveals that Zn-O bond becomes stronger with the increase in oxygen fraction in the reactive gas mixture. The lattice distortion or stress depends on the type of defects introduced during deposition. PL spectra show the formation of a shoulder in band emission with an increase in the processing pressure and are related to the presence of stress. The ratio of band emission to defect emission decreases with the increase in oxygen percentage from 50 to 100%. The studies show a correlation of stress with the structural, vibrational, and photoluminescence properties of the ZnO thin film. The systematic study of the stress will help in the fabrication of efficient devices based on ZnO film.
Menon, Rashmi; Gupta, Vinay; Sreenivas, K. [Electronic Material and Devices Laboratory, Department of Physics and Astrophysics, University of Delhi, Delhi 11007 (India); Tan, H. H.; Jagadish, C. [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia)
Science Conference Proceedings (OSTI)
Large and powerful negative hydrogen ion sources are required for the neutral beam injection (NBI) systems of future fusion devices. Simplicity and maintenance-free operation favors RF sources, which are developed intensively at the Max-Planck-Institut fuer Plasmaphysik (IPP) since many years. The negative hydrogen ions are generated by caesium-enhanced surface conversion of atoms and positive ions on the plasma grid surface. With a small scale prototype the required high ion current density and the low fraction of co-extracted electrons at low pressure as well as stable pulses up to 1 h could be demonstrated. The modular design allows extension to large source dimensions. This has led to the decision to choose RF sources for the NBI of the international fusion reactor, ITER. As an intermediate step towards the full size ITER source at IPP, the development will be continued with a half-size source on the new ELISE testbed. This will enable to gain experience for the first time with negative hydrogen ion beams from RF sources of these dimensions.
Kraus, W.; Fantz, U.; Franzen, P.; Froeschle, M.; Heinemann, B.; Riedl, R.; Wuenderlich, D. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, 85748 Garching (Germany)
Direct thrust measurements and modelling of a radio-frequency expanding plasma thruster
It is shown analytically that the thrust from a simple plasma thruster (in the absence of a magnetic field) is given by the maximum upstream electron pressure, even if the plasma diverges downstream. Direct thrust measurements of a thruster are then performed using a pendulum thrust balance and a laser displacement sensor. A maximum thrust of about 2 mN is obtained at 700 W for a thruster length of 17.5 cm and a flow rate of 0.9 mg s{sup -1}, while a larger thrust of 4 mN is obtained at a similar power for a length of 9.5 cm and a flow rate of 1.65 mg s{sup -1}. The measured thrusts are in good agreement with the maximum upstream electron pressure found from measurements of the plasma parameters and in fair agreement with a simple global approach used to model the thruster.
Lafleur, T.; Charles, C.; Boswell, R. W. [Space Plasma, Power and Propulsion Group, Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200 (Australia); Takahashi, K. [Space Plasma, Power and Propulsion Group, Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200 (Australia); Department of Electrical Engineering and Computer Science, Iwate University, Morioka 020-8551 (Japan)
Fluid modeling of radio frequency and direct currents in a biased magnetized plasma
This model aims at simulating a magnetized plasma column connected on one side to a probe and on the other side to an ICRH (Ion Cyclotron Resonant Heating) antenna. This is a double probe modeling of a plasma flux tube exchanging perpendicular currents: rf polarization current and dc currents (inertia, viscous, and friction) perpendicular to the magnetic field. A self consistent solution for the rectified potential and the density is obtained under the assumptions of flute hypothesis, inertialess electrons, and no collision in parallel direction. The main effect of rf biasing on the antenna side is to shift the IV characteristic so that the floating potential can be increased up to ln(I{sub 0}(eV{sub rf}/(k{sub B}T{sub e}))), with I{sub 0} the modified Bessel function of the first kind. On the contrary, the effect of dc currents is to decrease the plasma potential and the sheath potential which can be lower than 3k{sub B}T{sub e}/e or even be negative. Experimental characteristics are well matched by the 1D fluid code and exhibit very high negative currents (more than 30 j{sub i} the ion saturation current) for high positive biasing of the probe and for long flux tube (10 m). The non-saturation of the electron current is here due to high transverse transport enhanced by convective fluxes and dc currents able to bring an amount of density around the biased flux tube. During comparisons with experiments, the floating potential measured by a reciprocating probe is recovered by the code revealing that for a 120 V measured peak potential on the probe, the rf potential on the ICRH antenna is twice this value. Finally, the density profile can be flattened or steepened as a function of the transverse dc current direction.
Faudot, E.; Heuraux, S. [IJL-P2M UMR 7198 CNRS, F-54506 Vandoeuvre les Nancy, IJL, P2M-Faculte des Sciences, Vandoeuvre les Nancy 54506 (France); Kubic, M.; Gunn, J.; Colas, L. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France)
Porcelain-coated antenna for radio-frequency driven plasma source
A new porcelain-enamel coated antenna creates a clean plasma for volume or surface-conversion ion sources. The porcelain-enamel coating is hard, electrically insulating, long lasting, non fragile, and resistant to puncture by high energy ions in the plasma. Plasma and ion production using the porcelain enamel coated antenna is uncontaminated with filament or extraneous metal ion because the porcelain does not evaporate and is not sputtered into the plasma during operation. Ion beams produced using the new porcelain-enamel coated antenna are useful in ion implantation, high energy accelerators, negative, positive, or neutral beam applications, fusion, and treatment of chemical or radioactive waste for disposal. For ion implantation, the appropriate species ion beam generated with the inventive antenna will penetrate large or small, irregularly shaped conducting objects with a narrow implantation profile.
Leung, Ka-Ngo (Hercules, CA); Wells, Russell P. (Kensington, CA); Craven, Glen E. (Fremont, CA)
Radio-frequency powered glow discharge device and method with high voltage interface
A high voltage accelerating potential, which is supplied by a high voltage direct current power supply, is applied to the electrically conducting interior wall of an RF powered glow discharge cell. The RF power supply desirably is electrically grounded, and the conductor carrying the RF power to the sample held by the probe is desirably shielded completely excepting only the conductor's terminal point of contact with the sample. The high voltage DC accelerating potential is not supplied to the sample. A high voltage capacitance is electrically connected in series between the sample on the one hand and the RF power supply and an impedance matching network on the other hand. The high voltage capacitance isolates the high DC voltage from the RF electronics, while the RF potential is passed across the high voltage capacitance to the plasma. An inductor protects at least the RF power supply, and desirably the impedance matching network as well, from a short that might occur across the high voltage capacitance. The discharge cell and the probe which holds the sample are configured and disposed to prevent the probe's components, which are maintained at ground potential, from bridging between the relatively low vacuum region in communication with the glow discharge maintained within the cell on the one hand, and the relatively high vacuum region surrounding the probe and cell on the other hand. The probe and cell also are configured and disposed to prevent the probe's components from electrically shorting the cell's components. 11 figures.
Duckworth, D.C.; Marcus, R.K.; Donohue, D.L.; Lewis, T.A.
Radio-frequency powered glow discharge device and method with high voltage interface
A high voltage accelerating potential, which is supplied by a high voltage direct current power supply, is applied to the electrically conducting interior wall of an RF powered glow discharge cell. The RF power supply desirably is electrically grounded, and the conductor carrying the RF power to the sample held by the probe is desirably shielded completely excepting only the conductor's terminal point of contact with the sample. The high voltage DC accelerating potential is not supplied to the sample. A high voltage capacitance is electrically connected in series between the sample on the one hand and the RF power supply and an impedance matching network on the other hand. The high voltage capacitance isolates the high DC voltage from the RF electronics, while the RF potential is passed across the high voltage capacitance to the plasma. An inductor protects at least the RF power supply, and desirably the impedance matching network as well, from a short that might occur across the high voltage capacitance. The discharge cell and the probe which holds the sample are configured and disposed to prevent the probe's components, which are maintained at ground potential, from bridging between the relatively low vacuum region in communication with the glow discharge maintained within the cell on the one hand, and the relatively high vacuum region surrounding the probe and cell on the other hand. The probe and cell also are configured and disposed to prevent the probe's components from electrically shorting the cell's components.
Duckworth, Douglas C. (Knoxville, TN); Marcus, R. Kenneth (Clemson, SC); Donohue, David L. (Vienna, AT); Lewis, Trousdale A. (Oak Ridge, TN)
Sympathetic Cooling of 4 Ions in a Radio-Frequency Trap
interesting perspectives for performing precision tests of QED and measurements of nuclear radii. This Letter) as input. Precise values of the He nuclear radii can test theoretical nuclear methods and force models experimental uncertainty test the nuclear and the recently improved theoretical QED contributions
Schiller, Stephan
Design of the Radio-Frequency System for the 184-inch Cyclotron
dee by a half-wave transmission line. Much of the history oftor connected by a transmission line, operating wi th a nodenodal point of the transmission lines, greatly simplifying
McKenzie, K.R.
by liquid spray injection of disilanes into an argonhydrogen RF plasma operat- ing at 2040 kPa [4]. Here
Zachariah, Michael R.
Design of the Radio-Frequency System for the 184-inch Cyclotron
per second by a rotating condenser conneoted to the dee by amodulation by a rotating condenser were fairly certainin which a rotating condenser is mounted directly at the
McKenzie, K.R.
Measuring High-Frequency Humidity, Temperature and Radio Refractive Index in the Surface Layer
Science Conference Proceedings (OSTI)
Three different instrument systems are compared in their ability to either directly or indirectly measure humidity, temperature, and refractive-index fluctuations. Each system consists of a basic instrument�a Lyman-? hygrometer, an infrared ...
J. T. Priestley; R. J. Hill
Radio-frequency emission from an explosive instability in an electron beam
The explosive instability which occurs when an electron beam moves through a helical resonator is studied. This instability can be exploited to generate rf oscillations at high efficiency (20% in these experiments). The spectral width is narrower than the characteristic width for linear instabilities.
Buts, V.A.; Izmailov, A.N.
Preliminary Concept for the Project X CW Radio Frequency Quadrupole (RFQ)
Spallation Neutron Source (SNS) Front End [3] as well as awas used successfully on the SNS RFQ, which used Glidcop forsimilar to those used on the SNS RFQ. The preliminary design
Virostek, S. P.
Localized electrical fine tuning of passive microwave and radio frequency devices
A method and apparatus for the localized electrical fine tuning of passive multiple element microwave or RF devices in which a nonlinear dielectric material is deposited onto predetermined areas of a substrate containing the device. An appropriate electrically conductive material is deposited over predetermined areas of the nonlinear dielectric and the signal line of the device for providing electrical contact with the nonlinear dielectric. Individual, adjustable bias voltages are applied to the electrically conductive material allowing localized electrical fine tuning of the devices. The method of the present invention can be applied to manufactured devices, or can be incorporated into the design of the devices so that it is applied at the time the devices are manufactured. The invention can be configured to provide localized fine tuning for devices including but not limited to coplanar waveguides, slotline devices, stripline devices, and microstrip devices.
Findikoglu, Alp T. (Los Alamos, NM)
Faraday Acceleration with Radio-frequency Assisted Discharge Edgar Y. Choueiri and Kurt A. Polzin
, CA, July 10-12, 1989. AIAA 89-2266. 18 T.E. Markusic. Current sheet canting in pulsed electromagnetic accelerators. PhD thesis, Dept. of Mechanical and 27 #12;CHOUEIRI AND POLZIN FARAD Concept Aerospace
Choueiri, Edgar
Electrical Powering Concept for ITER Electron Cyclotron Radio-Frequency Sources
Science Conference Proceedings (OSTI)
Technical Paper / Special Issue on Electron Cyclotron Wave Physics, Technology, and Applications - Part 2
D. Fasel; T. Bonicelli; M. A. Henderson; M. Q. Tran
Structural properties of dusty plasma in direct current and radio frequency gas discharges
Science Conference Proceedings (OSTI)
This paper presents radial distribution functions of dust particles obtained experimentally in dc and rf discharges. Pressure and interaction energy of dusty particles were calculated on the basis of these functions. The Langevin dynamics computer simulation for each experiment was performed. The comparisons with computer simulations are made.
Ramazanov, T. S.; Dzhumagulova, K. N.; Jumabekov, A. N.; Dosbolayev, M. K. [Al Farabi Kazakh National University, IETP, Tole bi 96a, Almaty, 050012 (Kazakhstan)
·11 /2 Tbsp whole wheat flour · 1 /2 Tbsp whole wheat flour and 1 /2 Tbsp all-purpose flour Flour, 1 flour, result in a rye flour or whole wheat flour and reduced volume 1 /2 cup all-purpose flour and a · 3 /4 cup whole wheat flour or bran heavier product. flour and 1 /4 cup all-purpose flour ·1 cup rye
Tang, Juming
Radio-Frequency Beam Conditioner for Fast-Wave Free-Electron Generators of Coherent Radiation
California 94720 Li-Hua Yu Brookhaven National Laboratory,California Li-Hua Yu Brookhaven National Laboratory, Upton,based upon the proposed Brookhaven National Laboratory VUV
Sessler, Andrew M.
Radio frequency magnetron sputter deposition of CaF{sub 2} films
Science Conference Proceedings (OSTI)
Calcium fluoride films have been deposited onto unheated ({lt}100{degree}C) substrates by low power rf magnetron sputtering of CaF{sub 2} targets using Ar and Ne process gases at pressures of 0.5{endash}2.7 Pa, biased and floating substrate potentials, and various geometries of the substrate with respect to the source. The thickness and composition of the films are very sensitive to resputtering of the growing film. Uniform and stoichiometric films were most readily obtained on off-axis substrates using two sputter sources oriented with the targets facing each other. The films were found to be crystalline, have a fine textured microstructure, and to be transparent and highly resistive. {copyright} {ital 1998 American Vacuum Society.}
Dudney, N.J. [Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6030 (United States)
Radio-frequency and microwave load comprising a carbon-bonded carbon fiber composite
A billet of low-density carbon-bonded carbon fiber (CBCF) composite is machined into a desired attenuator or load element shape (usually tapering). The CBCF composite is used as a free-standing load element or, preferably, brazed to the copper, brass or aluminum components of coaxial transmission lines or microwave waveguides. A novel braze method was developed for the brazing step. The resulting attenuator and/or load devices are robust, relatively inexpensive, more easily fabricated, and have improved performance over conventional graded-coating loads.
Lauf, Robert J. (Oak Ridge, TN); McMillan, April D. (Knoxville, TN); Johnson, Arvid C. (Lake in the Hills, IL); Everleigh, Carl A. (Raleigh, NC); Moorhead, Arthur J. (Knoxville, TN)
Radio-frequency and microwave load comprising a carbon-bonded carbon fiber composite
A billet of low-density carbon-bonded carbon fiber (CBCF) composite is machined into a desired attenuator or load element shape (usually tapering). The CBCF composite is used as a free-standing load element or, preferably, brazed to the copper, brass or aluminum components of coaxial transmission lines or microwave waveguides. A novel braze method was developed for the brazing step. The resulting attenuator and/or load devices are robust, relatively inexpensive, more easily fabricated, and have improved performance over conventional graded-coating loads. 9 figs.
Lauf, R.J.; McMillan, A.D.; Johnson, A.C.; Everleigh, C.A.; Moorhead, A.J.
Preliminary Concept for the Project X CW Radio Frequency Quadrupole (RFQ)
This work was supported by the Director, Office of Science,Office of Fusion Energy Sciences, of the U.S. Department ofwas supported by the Office of Science, U. S. Department of
Virostek, S. P.
Science Conference Proceedings (OSTI)
The Large Area Telescope (LAT) instrument onboard GLAST offers a tremendous opportunity for future blazar studies. In order to fully benefit from its capabilities and to maximize the scientific return from the LAT, it is of great importance to conduct dedicated multi-frequency monitoring campaigns that will result comprehensive observations. Consequently, we initiated an effort to conduct a GLAST-dedicated, quasi-simultaneous, broad-band flux-density (and polarization) monitoring of potential GLAST blazars with the Effelsberg and OVRO radio telescopes (11 cm to 7mm wavelength). Here, we present a short overview of these activities which will complement the multi-wavelengths activities of the GLAST/LAT collaboration towards the 'low-energy' radio bands. Further we will give a brief outlook including the extension of this coordinated campaign towards higher frequencies and future scientific aims.
Fuhrmann, L.; Zensus, J.A.; Krichbaum, T.P.; Angelakis, E.; /Bonn, Max Planck Inst., Radioastron.; Readhead, A.C.S.; /Caltech
AEGIS20: a radio survey of the Extended Groth Strip
We describe AEGIS20 - a radio survey of the Extended Groth Strip (EGS) conducted with the Very Large Array (VLA) at 1.4GHz. The resulting catalog contains 1,123 emitters and is sensitive to ultraluminous starbursts to z1 where correcting for contamination by radio-loud active galactic nuclei (AGN) comes at the price of rejecting luminous starbursts. Whilst stacking radio images is a useful technique, accurate radio-based SFRs for z>>1 galaxies require precise redshifts and extraordinarily high-fidelity radio data to identify and remove accretion-related emission.
R. J. Ivison; S. C. Chapman; S. M. Faber; Ian Smail; A. D. Biggs; C. J. Conselice; G. Wilson; S. Salim; J. -S. Huang; S. P. Wilner
Design and implementation of frequency synthesizers for 3-10 ghz mulitband ofdm uwb communication
The allocation of frequency spectrum by the FCC for Ultra Wideband (UWB) communications in the 3.1-10.6 GHz has paved the path for very high data rate Gb/s wireless communications. Frequency synthesis in these communication systems involves great challenges such as high frequency and wideband operation in addition to stringent requirements on frequency hopping time and coexistence with other wireless standards. This research proposes frequency generation schemes for such radio systems and their integrated implementations in silicon based technologies. Special emphasis is placed on efficient frequency planning and other system level considerations for building compact and practical systems for carrier frequency generation in an integrated UWB radio. This work proposes a frequency band plan for multiband OFDM based UWB radios in the 3.1-10.6 GHz range. Based on this frequency plan, two 11-band frequency synthesizers are designed, implemented and tested making them one of the first frequency synthesizers for UWB covering 78% of the licensed spectrum. The circuits are implemented in 0.25�m SiGe BiCMOS and the architectures are based on a single VCO at a fixed frequency followed by an array of dividers, multiplexers and single sideband (SSB) mixers to generate the 11 required bands in quadrature with fast hopping in much less than 9.5 ns. One of the synthesizers is integrated and tested as part of a 3-10 GHz packaged receiver. It draws 80 mA current from a 2.5 V supply and occupies an area of 2.25 mm2. Finally, an architecture for a UWB synthesizer is proposed that is based on a single multiband quadrature VCO, a programmable integer divider with 50% duty cycle and a single sideband mixer. A frequency band plan is proposed that greatly relaxes the tuning range requirement of the multiband VCO and leads to a very digitally intensive architecture for wideband frequency synthesis suitable for implementation in deep submicron CMOS processes. A design in 130nm CMOS occupies less than 1 mm2 while consuming 90 mW. This architecture provides an efficient solution in terms of area and power consumption with very low complexity.
Mishra, Chinmaya
Type I noise storms constitute a sizeable faction of the active-Sun radio emission component. Observations of isolated instances of such bursts, in the swept-frequency-mode at metric wavelengths, have remained sparse, with several unfilled regions in the frequency coverage. Dynamic spectra of the burst radiation, in the 30 - 130 MHz band, obtained from the recently commissioned digital High Resolution Spectrograph (HRS) at the Gauribidanur Radio Observatory, on account of the superior frequency and time resolution, have unravelled in explicit detail the temporal and spectral profiles of isolated bursts. Apart from presenting details on their fundamental emission features, the time and frequency profile symmetry, with reference to custom-specific Gaussian distributions, has been chosen as the nodal criterion to statistically explain the state of the source regions in the vicinity of magnetic reconnections, the latent excitation agent that contributes to plasma wave energetics, and the quenching phenomenon that causes damping of the burst emission.
G. A. Shanmugha Sundaram; K. R. Subramanian
Type I noise storms constitute a sizeable faction of the active-Sun radio emission component. Observations of isolated instances of such bursts, in the swept-frequency-mode at metric wavelengths, have remained sparse, with several unfilled regions in the frequency coverage. Dynamic spectra of the burst radiation, in the 30 - 130 MHz band, obtained from the recently commissioned digital High Resolution Spectrograph (HRS) at the Gauribidanur Radio Observatory, on account of the superior frequency and time resolution, have unravelled in explicit detail the temporal and spectral profiles of isolated bursts. Apart from presenting details on their fundamental emission features, the time and frequency profile symmetry, with reference to custom-specific Gaussian distributions, has been chosen as the nodal criterion to statistically explain the state of the source regions in the vicinity of magnetic reconnections, the latent excitation agent that contributes to plasma wave energetics, and the quenching phenomenon that...
Sundaram, G A S
Marine asset security and tracking (MAST) system
Methods and apparatus are described for marine asset security and tracking (MAST). A method includes transmitting identification data, location data and environmental state sensor data from a radio frequency tag. An apparatus includes a radio frequency tag that transmits identification data, location data and environmental state sensor data. Another method includes transmitting identification data and location data from a radio frequency tag using hybrid spread-spectrum modulation. Another apparatus includes a radio frequency tag that transmits both identification data and location data using hybrid spread-spectrum modulation.
Hanson, Gregory Richard (Clinton, TN); Smith, Stephen Fulton (Loudon, TN); Moore, Michael Roy (Corryton, TN); Dobson, Eric Lesley (Charleston, SC); Blair, Jeffrey Scott (Charleston, SC); Duncan, Christopher Allen (Marietta, GA); Lenarduzzi, Roberto (Knoxville, TN)
A New Trend in Collection and Transportation Management of ...
Science Conference Proceedings (OSTI)
In the system, Radio Frequency Identification (RFID) technology is applied to the integrated management of MSW, which include collection, transportation, and�...
A13: In Vivo Evaluation of Zirconia Toughened Alumina Ceramics
Science Conference Proceedings (OSTI)
G8: Low-Cost Corrosion Monitoring Sensors Based on Radio Frequency Identification (RFID) Technology � G9: The Protection of Iron Reducing Bacteria (
H11: Crystalline Approximants of SiCO: Implications on Structure ...
Science Conference Proceedings (OSTI)
G8: Low-Cost Corrosion Monitoring Sensors Based on Radio Frequency Identification (RFID) Technology � G9: The Protection of Iron Reducing Bacteria (
B4: Dielectric and Ferroelectric Characteristics of Ba0.90Sr0.10TiO3 ...
Science Conference Proceedings (OSTI)
G8: Low-Cost Corrosion Monitoring Sensors Based on Radio Frequency Identification (RFID) Technology � G9: The Protection of Iron Reducing Bacteria (
B48: Fast Sintering of SnO 2 Nanoparticles after Chemical Lixiviation
Science Conference Proceedings (OSTI)
G8: Low-Cost Corrosion Monitoring Sensors Based on Radio Frequency Identification (RFID) Technology � G9: The Protection of Iron Reducing Bacteria (
Chemical and Thermal Reductions of Carboxylate-protected ...
Science Conference Proceedings (OSTI)
... manufacture fine-pitch electrical line patterns for organic transistors and radio frequency identification (RFID) antennas, not only because of the high electrical�...
E38: Structural, Mossbauer and Magnetic Properties of Z-Type ...
Science Conference Proceedings (OSTI)
G8: Low-Cost Corrosion Monitoring Sensors Based on Radio Frequency Identification (RFID) Technology � G9: The Protection of Iron Reducing Bacteria (
H18: Comparaison of a Gamma Titanium Aluminide Fabricated by ...
Science Conference Proceedings (OSTI)
G8: Low-Cost Corrosion Monitoring Sensors Based on Radio Frequency Identification (RFID) Technology � G9: The Protection of Iron Reducing Bacteria (
F4: Microstructure and Mechanical Properties of Mn-Based ...
Science Conference Proceedings (OSTI)
G8: Low-Cost Corrosion Monitoring Sensors Based on Radio Frequency Identification (RFID) Technology � G9: The Protection of Iron Reducing Bacteria (
D18: Pure and Doped Ceria Nanoparticles for Green Natural Gas ...
Science Conference Proceedings (OSTI)
G8: Low-Cost Corrosion Monitoring Sensors Based on Radio Frequency Identification (RFID) Technology � G9: The Protection of Iron Reducing Bacteria (
B40: The Properties of Austenitic Stainless Steel Reinforced with ...
Science Conference Proceedings (OSTI)
G8: Low-Cost Corrosion Monitoring Sensors Based on Radio Frequency Identification (RFID) Technology � G9: The Protection of Iron Reducing Bacteria (
H16: Microstructural Evolution and Its Affect on Mechanical ...
Science Conference Proceedings (OSTI)
G8: Low-Cost Corrosion Monitoring Sensors Based on Radio Frequency Identification (RFID) Technology � G9: The Protection of Iron Reducing Bacteria (
J14: Synthesis and Characterization of Porous Titania through ...
Science Conference Proceedings (OSTI)
G8: Low-Cost Corrosion Monitoring Sensors Based on Radio Frequency Identification (RFID) Technology � G9: The Protection of Iron Reducing Bacteria (
RFID security protocols simulation and prototyping.
??As Radio Frequency Identification (RFID) technology achieves commercial success, its privacy and security issues are becoming a barrier to limit its potential for future start� (more)
Yu, Xiaohui
Resonant circuit which provides dual frequency excitation for rapid cycling of an electromagnet
Disclosed is a ring magnet control circuit that permits synchrotron repetition rates much higher than the frequency of the cosinusoidal guide field of the ring magnet during particle acceleration. the control circuit generates cosinusoidal excitation currents of different frequencies in the half waves. During radio frequency acceleration of the particles in the synchrotron, the control circuit operates with a lower frequency cosine wave and thereafter the electromagnets are reset with a higher frequency half cosine wave. Flat-bottom and flat-top wave shaping circuits maintain the magnetic guide field in a relatively time-invariant mode during times when the particles are being injected into the ring magnets and when the particles are being ejected from the ring magnets.
Praeg, Walter F. (Palos Park, IL)
A dichotomy in radio jet orientations
We examine the relative orientations of radio jets, central dust and stars in low-power (i.e., FR I and FR I/II) radio galaxies. We use the position angles of jet and dust to constrain the three-dimensional angle $\\theta_{\\rm DJ}$ between jet and dust. For galaxies with filamentary dust 'lanes' (which tend to be misaligned with the galaxy major axis) the jet is approximately perpendicular to the dust structure, while for galaxies with elliptical dust distributions (typically aligned with the galaxy major axis) there is a much wider distribution of $\\theta_{\\rm DJ}$. nThe dust ellipses are consistent with being nearly circular thin disks viewed at random viewing angles. The lanes are likely warped, unsettled dust structures. We consider two scenarios to explain the dust/jet orientation dichotomy.
Gijs Verdoes Kleijn; Tim de Zeeuw
Vectorial Radio Interferometry with LOPES 3D
One successful detection technique for high-energy cosmic rays is based on the radio signal emitted by the charged particles in an air shower. The LOPES experiment at Karlsruhe Institute of Technology, Germany, has made major contributions to the evolution of this technique. LOPES was reconfigured several times to improve and further develop the radio detection technique. In the latest setup LOPES consisted of 10 tripole antennas. With this, LOPES 3D was the first cosmic ray experiment measuring all three vectorial field components at once and thereby gaining the full information about the electric field vector. We present an analysis based on the data taken with special focus on the benefits of a direct measurement of the vertical polarization component. We demonstrate that by measuring all polarization components the detection and reconstruction efficiency is increased and noisy single channel data can be reconstructed by utilising the information from the other two channels of one antenna station.
Huber, D; Arteaga, J C; B�hren, L; Bekk, K; Bertaina, M; Biermann, P L; Bl�mer, J; Bozdog, H; Brancus, I M; Chiavassa, A; Daumiller, K; de Souza, V; Di Pierro, F; Doll, P; Engel, R; Falcke, H; Fuchs, B; Fuhrmann, D; Gemmeke, H; Grupen, C; Haungs, A; Heck, D; H�randel, J R; Horneffer, A; Huege, T; Isar, P G; Kampert, K H; Kang, D; Kr�mer, O; Kuijpers, J; Link, K; ?uczak, P; Ludwig, M; Mathes, H J; Melissas, M; Morello, C; Oehlschl�ger, J; Palmieri, N; Pierog, T; Rautenberg, J; Rebel, H; Roth, M; R�hle, C; Saftoiu, A; Schieler, H; Schmid, A; Schr�der, F G; Sima, O; Toma, G; Trinchero, G C; Weindl, A; Wochele, J; Wommer, M; Zabierowski, J; Zensus, J A
Office of Legacy Management (LM)
RADIoLOGICALsURvEY RADIoLOGICALsURvEY AT 1411 CENTRAL AVENUE DETROIT, MICHIGAN Prepared by M.R. LANDIS Environmental Survey and Site Assessment Program Energy/Environment Systems Division Oak Ridge Associated Universities Oak Ridge, TN 37831-0117 Project Staff J.D. Berger H.J. Laudeman C.H. Searcy T.J. Sowell D.A. Gibson E.A. Powell S.M. Shanmugan C.F. Weaver Prepared for U.S. Department of Energy as part of the Formerly Utilized Sites - Remedial Action Program FINAL REPORT FEBRUARY 1990 This report is based on work performed under contract number DE-AC05-760R00033 with the U.S. Department of Energy. TABLE OF CONTENTS ListofFigures .......................... List of Tables. ........................... Introduction ............................ Facility Description. ........................
PINS Spectrum Identification Guide
The Portable Isotopic Neutron Spectroscopy�PINS, for short�system identifies the chemicals inside munitions and containers without opening them, a decided safety advantage if the fill chemical is a hazardous substance like a chemical warfare agent or an explosive. The PINS Spectrum Identification Guide is intended as a reference for technical professionals responsible for the interpretation of PINS gamma-ray spectra. The guide is divided into two parts. The three chapters that constitute Part I cover the science and technology of PINS. Neutron activation analysis is the focus of Chapter 1. Chapter 2 explores PINS hardware, software, and related operational issues. Gamma-ray spectral analysis basics are introduced in Chapter 3. The six chapters of Part II cover the identification of PINS spectra in detail. Like the PINS decision tree logic, these chapters are organized by chemical element: phosphorus-based chemicals, chlorine-based chemicals, etc. These descriptions of hazardous, toxic, and/or explosive chemicals conclude with a chapter on the identification of the inert chemicals, e.g. sand, used to fill practice munitions.
A.J. Caffrey
Animation of JILA Frequency Comb Spectroscopy Technique
Science Conference Proceedings (OSTI)
Animation of JILA Frequency Comb Spectroscopy Technique. The new JILA "frequency comb spectroscopy" technique ...
Laser-frequency multiplication
A high quality mode locked pulse train was obtained at 9.55 micrometers, the CO2 wavelength chosen for frequency doubling into the atmospheric window at 4.8 micrometers. The pulse train consists of a 3 micro sec burst of 1.5 nsec pulses separated by 40 nsec, in a TEM(00) mode and with a total energy of 100 mJ. The pulse intensity without focussing is about 3 MW/sq.cm., already quite close to the target intensity of 10 MW/sq.cm. for frequency doubling in a AgGaSe2 crystal. The mode-locked train is obtained by intracavity modulation at 12.5 MHz using a germanium crystal driven with a power of about 30 Watts. Line selection is achieved firstly by the use of a 0.92 mm thick CaF2 plate at the Brewster angle within the cavity, which completely suppresses 10.6 micrometer band radiation. Secondly, a particular rotational line, the P20 at 9.55 micrometers, is selected by the injection of a continuous beam is mode-matched to the pulsed laser cavity using a long focal length lens, and for best line-locking it is necessary to fine tune the length of the pulsed laser resonator. Injection causes substantial depression of the gain switched spike.
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Barrier Immune Radio Communications for Demand Response
NLE Websites -- All DOE Office Websites (Extended Search)
Barrier Immune Radio Communications for Demand Response Barrier Immune Radio Communications for Demand Response Title Barrier Immune Radio Communications for Demand Response Publication Type Report LBNL Report Number LBNL-2294e Year of Publication 2009 Authors Rubinstein, Francis M., Girish Ghatikar, Jessica Granderson, Paul Haugen, Carlos Romero, and David S. Watson Keywords technologies Abstract Various wireless technologies were field-tested in a six-story laboratory building to identify wireless technologies that can scale for future DR applications through very low node density power consumption, and unit cost. Data analysis included analysis of the signal-to-noise ratio (SNR), packet loss, and link quality at varying power levels and node densities. The narrowband technologies performed well, penetrating the floors of the building with little loss and exhibiting better range than the wideband technology. 900 MHz provided full coverage at 1 watt and substantially complete coverage at 500 mW at the test site. 900 MHz was able to provide full coverage at 100 mW with only one additional relay transmitter, and was the highest-performing technology in the study. 2.4 GHz could not provide full coverage with only a single transmitter at the highest power level tested (63 mW). However, substantially complete coverage was provided at 2.4 GHz at 63 mW with the addition of one repeater node.
The hydrodynamics of dead radio galaxies
We present a numerical investigation of dead, or relic, radio galaxies and the environmental impact that radio galaxy activity has on the host galaxy or galaxy cluster. We perform axisymmetric hydrodynamical calculations of light, supersonic, back-to-back jets propagating in a beta-model galaxy/cluster atmosphere. We then shut down the jet activity and let the resulting structure evolve passively. The dead source undergoes an initial phase of pressure driven expansion until it achieves pressure equilibrium with its surroundings. Thereafter, buoyancy forces drive the evolution and lead to the formation of two oppositely directed plumes that float high into the galaxy/cluster atmosphere. These plumes entrain a significant amount of low entropy material from the galaxy/cluster core and lift it high into the atmosphere. An important result is that a large fraction (at least half) of the energy injected by the jet activity is thermalized in the ISM/ICM core. The whole ISM/ICM atmosphere inflates in order to regain hydrostatic equilibrium. This inflation is mediated by an approximately spherical disturbance which propagates into the atmosphere at the sound speed. The fact that such a large fraction of the injected energy is thermalized suggests that radio galaxies may have an important role in the overall energy budget of rich ISM/ICM atmospheres. In particular, they may act as a strong and highly time-dependent source of negative feedback for galaxy/cluster cooling flows.
C. S. Reynolds; S. Heinz; M. C. Begelman
Design of frequency synthesizers for short range wireless transceivers
The rapid growth of the market for short-range wireless devices, with standards such as Bluetooth and Wireless LAN (IEEE 802.11) being the most important, has created a need for highly integrated transceivers that target drastic power and area reduction while providing a high level of integration. The radio section of the devices designed to establish communications using these standards is the limiting factor for the power reduction efforts. A key building block in a transceiver is the frequency synthesizer, since it operates at the highest frequency of the system and consumes a very large portion of the total power in the radio. This dissertation presents the basic theory and a design methodology of frequency synthesizers targeted for short-range wireless applications. Three different examples of synthesizers are presented. First a frequency synthesizer integrated in a Bluetooth receiver fabricated in 0.35?m CMOS technology. The receiver uses a low-IF architecture to downconvert the incoming Bluetooth signal to 2MHz. The second synthesizer is integrated within a dual-mode receiver capable of processing signals of the Bluetooth and Wireless LAN (IEEE 802.11b) standards. It is implemented in BiCMOS technology and operates the voltage controlled oscillator at twice the required frequency to generate quadrature signals through a divide-by-two circuit. A phase switching prescaler is featured in the synthesizer. A large capacitance is integrated on-chip using a capacitance multiplier circuit that provides a drastic area reduction while adding a negligible phase noise contribution. The third synthesizer is an extension of the second example. The operation range of the VCO is extended to cover a frequency band from 4.8GHz to 5.85GHz. By doing this, the synthesizer is capable of generating LO signals for Bluetooth and IEEE 802.11a, b and g standards. The quadrature output of the 5 - 6 GHz signal is generated through a first order RC - CR network with an automatic calibration loop. The loop uses a high frequency phase detector to measure the deviation from the 90� separation between the I and Q branches and implements an algorithm to minimize the phase errors between the I and Q branches and their differential counterparts.
Valero Lopez, Ari Yakov
Science Conference Proceedings (OSTI)
Green Peas are a new class of young, emission line galaxies that were discovered by citizen volunteers in the Galaxy Zoo project. Their low stellar mass, low metallicity, and very high star formation rates make Green Peas the nearby (z {approx} 0.2) analogs of the Lyman break galaxies which account for the bulk of the star formation in the early universe (z {approx} 2-5). They thus provide accessible laboratories in the nearby universe for understanding star formation, supernova feedback, particle acceleration, and magnetic field amplification in early galaxies. We report the first direct radio detection of Green Peas with low frequency Giant Metrewave Radio Telescope observations and our stacking detection with archival Very Large Array FIRST data. We show that the radio emission implies that these extremely young galaxies already have magnetic fields ({approx}> 30 {mu}G) even larger than that of the Milky Way. This is at odds with the present understanding of magnetic field growth based on amplification of seed fields by dynamo action over a galaxy's lifetime. Our observations strongly favor models with pregalactic magnetic fields at {mu}G levels.
Chakraborti, Sayan; Yadav, Naveen; Ray, Alak [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Colaba, Mumbai 400005 (India); Cardamone, Carolin, E-mail: firstname.lastname@example.com [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Bldg. 26-331, Cambridge, MA 02139 (United States)
Source Catalog Data from FIRST (Faint Images of the Radio Sky at Twenty-Centimeters)
FIRST, Faint Images of the Radio Sky at Twenty-Centimeters, is a project designed to produce the radio equivalent of the Palomar Observatory Sky Survey over 10,000 square degrees of the North Galactic Cap. Using the National Radio Astronomy Observatory's (NRAO) Very Large Array (VLA) in its B-configuration, the Survey acquired 3-minute snapshots covering a hexagonal grid using 2?7 3-MHz frequency channels centered at 1365 and 1435 MHz. The data were edited, self-calibrated, mapped, and CLEANed using an automated pipeline based largely on routines in the Astronomical Image Processing System (AIPS). A final atlas of maps is produced by coadding the twelve images adjacent to each pointing center. Source catalogs with flux densities and size information are generated from the coadded images also. The July, 2008 catalog is the latest version and has been tested to ensure reliability and completness. The catalog, generated from the 1993 through 2004 images, contains 816,000 sources and covers more than 9000 square degrees. A specialized search interface for the catalog resides at this website, and the catalog is also available as a compressed ASCII file. The user may also view earlier versions of the source catalog. The FIRST survey area was chosen to coincide with that of the Sloan Digital Sky Survey (SDSS); at the m(v)~24 limit of SDSS, ~50% of the optical counterparts to FIRST sources will be detected.
Becker, Robert H.; Helfand, David J.; White, Richard L.; Gregg, Michael D.; Laurent-Muehleisen, Sally A.
Probing Signal Design for Power System Identification
Science Conference Proceedings (OSTI)
This paper investigates the design of effective input signals for low-level probing of power systems. In 2005, 2006, and 2008 the Western Electricity Coordinating Council (WECC) conducted four large-scale system wide tests of the western interconnected power system where probing signals were injected by modulating the control signal at the Celilo end of the Pacific DC intertie. A major objective of these tests is the accurate estimation of the inter-area electromechanical modes. A key aspect of any such test is the design of an effective probing signal that leads to measured outputs rich in information about the modes. This paper specifically studies low-level probing signal design for power-system identification. The paper describes the design methodology and the advantages of this new probing signal which was successfully applied during these tests. This probing input is a multi-sine signal with its frequency content focused in the range of the inter-area modes. The period of the signal is over two minutes providing high-frequency resolution. Up to 15 cycles of the signal are injected resulting in a processing gain of 15. The resulting system response is studied in the time and frequency domains. Because of the new probing signal characteristics, these results show significant improvement in the output SNR compared to previous tests.
Pierre, John W.; Zhou, Ning; Tuffner, Francis K.; Hauer, John F.; Trudnowski, Daniel J.; Mittelstadt, William
In a laser system for converting infrared laser light waves to visible light comprising a source of infrared laser light waves and means of harmonic generation associated therewith for production of light waves at integral multiples of the frequency of the original wave, the improvement of said means of harmonic generation comprising a crystal having the chemical formula X{sub 2} Y(NO{sub 3}){sub 5} {center_dot} 2 nZ{sub 2}O wherein X is selected from the group consisting of Li, Na, K, Rb, Cs, and Tl; Y is selected from the group consisting of Sc, Y, La, Ce, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Ga, and In; Z is selected from the group consisting of H and D; and n ranges from 0 to 4.
Ebbers, C.A.; Davis, L.E.; Webb, M.
In a laser system for converting infrared laser light waves to visible light comprising a source of infrared laser light waves and means of harmonic generation associated therewith for production of light waves at integral multiples of the frequency of the original wave, the improvement of said means of harmonic generation comprising a crystal having the chemical formula X{sub 2} Y(NO{sub 3}){sub 5} {center dot} 2 nZ{sub 2}O wherein X is selected from the group consisting of Li, Na, K, Rb, Cs, and Tl; Y is selected from the group consisting of Sc, Y, La, Ce, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Ga, and In; Z is selected from the group consisting of H and D; and n ranges from 0 to 4.
Ebbers, C.A.; Davis, L.E.; Webb, M.
In a laser system for converting infrared laser light waves to visible light comprising a source of infrared laser light waves and means of harmoic generation associated therewith for production of light waves at integral multiples of the frequency of the original wave, the improvement of said means of harmonic generation comprising a crystal having the chemical formula X.sub.2 Y(NO.sub.3).sub.5 .multidot.2 nZ.sub.2 o wherein X is selected from the group consisting of Li, Na, K, Rb, Cs, and Tl; Y is selected from the group consisting of Sc, Y, La, Ce, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Ga, and In; Z is selected from the group consisting of H and D; and n ranges from 0 to 4.
Ebbers, Christopher A. (Livermore, CA); Davis, Laura E. (Manteca, CA); Webb, Mark (Salida, CA)
Low-power impulse UWB architectures and circuits
Ultra-wide-band (UWB) communication has a variety of applications ranging from wireless USB to radio frequency (RF) identification tags. For many of these applications, energy is critical due to the fact that the radios ...
Chandrakasan, Anantha P.
We present the results of deep, high-resolution, 5 GHz Expanded Very Large Array (EVLA) observations of the nearby, dwarf lenticular galaxy and intermediate-mass black hole candidate (M{sub BH} {approx} 4.5 Multiplication-Sign 10{sup 5} M{sub Sun }), NGC 404. For the first time, radio emission at frequencies above 1.4 GHz has been detected in this galaxy. We found a modestly resolved source in the NGC 404 nucleus with a total radio luminosity of 7.6 {+-} 0.7 Multiplication-Sign 10{sup 17} W Hz{sup -1} at 5 GHz and a spectral index from 5 to 7.45 GHz of {alpha} = -0.88 {+-} 0.30. NGC 404 is only the third central intermediate-mass black hole candidate detected in the radio regime with subarcsecond resolution. The position of the radio source is consistent with the optical center of the galaxy and the location of a known, hard X-ray point source (L{sub X} {approx} 1.2 Multiplication-Sign 10{sup 37} erg s{sup -1}). The faint radio and X-ray emission could conceivably be produced by an X-ray binary, star formation, a supernova remnant, or a low-luminosity active galactic nucleus powered by an intermediate-mass black hole. In light of our new EVLA observations, we find that the most likely scenario is an accreting intermediate-mass black hole, with other explanations being either incompatible with the observed X-ray and/or radio luminosities or statistically unlikely.
Nyland, Kristina; Marvil, Josh; Young, Lisa M. [Department of Physics, New Mexico Tech., 801 Leroy Place, Socorro, NM 87801 (United States); Wrobel, J. M. [National Radio Astronomy Observatory, Socorro, NM 87801 (United States); Zauderer, B. Ashley, E-mail: email@example.com [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
The F-GAMMA program is a coordinated effort to investigate the physics of Active Galactic Nuclei (AGNs) via multi-frequency monitoring of {\\em Fermi} blazars. The current study is concerned with the broad-band radio spectra composed of measurement at ten frequencies between 2.64 and 142 GHz. It is shown that any of the 78 sources studied can be classified in terms of their variability characteristics in merely 5 types of variability. The first four types are dominated by spectral evolution and can be reproduced by a simple two-component system made of the quiescent spectrum of a large scale jet populated with a flaring event evolving according to Marscher & Gear (1985). The last type is characterized by an achromatic change of the broad-band spectrum which must be attributed to a completely different mechanism. Here are presented, the classification, the assumed physical system and the results of simulations that have been conducted.
Angelakis, E; Nestoras, I; Fromm, C M; Schmidt, R; Zensus, J A; Marchili, N; Krichbaum, T P; Perucho-Pla, M; Ungerechts, H; Sievers, A; Riquelme, D
Solving the Frequency Assignment Problem by Site Availability and Constraint Programming
The efficient use of bandwidth for radio communications becomes more and more crucial when developing new information technologies and their applications. The core issues are addressed by the so-called Frequency Assignment Problems (FAP). Our work investigates static FAP, where an attempt is first made to configure a kernel of links. We study the problem based on the concepts and techniques of Constraint Programming and integrate the site availability concept. Numerical simulations conducted on scenarios provided by CELAR are very promising.
Linhares, Andrea Carneiro; Peinl, Peter; Michelon, Philippe
Distributed cooperative spectrum sensing in cognitive radio for ad hoc networks
Science Conference Proceedings (OSTI)
Cognitive radio refers to an intelligent radio with the capability of sensing the radio environment and dynamically reconfiguring the operating parameters. Recent research has focused on using cognitive radios in ad hoc environments. Spectrum sensing ... Keywords: Ad hoc networks, Cognitive radio, Spectrum sensing, TV spectrum
Waleed Ejaz, Najam Ul Hasan, Hyung Seok Kim
Radio ways| Society, locality, and FM technology in Koutiala, Mali.
?? This study in media anthropology uses participant observation, interviews, questionnaires, and recorded broadcasts to analyze how people use FM radio technology in the Koutiala� (more)
Tower, Craig
Most radiation from galaxies containing active galactic nuclei (AGNs) is emitted not by the stars composing the galaxy, but from an active source at the galactic center, most likely a supermassive black hole. Of particular interest are radio galaxies, active galaxies that emit much of their radiation at radio wavelengths. Within each radio galaxy, an AGN powers a pair of collimated jets of relativistic particles, forming a pair of giant lobes at the end of the jets and thus giving a characteristic double-lobed appearance. A particular class of radio galaxies has an �X�-or winged-shaped morphology: in these, two pairs of lobes appear to originate from the galactic center, producing a distinctive X-shape. Two main mechanisms have been proposed to explain the X-shape morphology: one being a realignment of the black hole within the AGN and the second positing that the radio jets are expanding into an asymmetric medium, causing backflow and producing secondary wings. By analyzing radio host galaxy shapes, the distribution of the stellar mass is compared to the differing model expectations regarding the distribution of the surrounding gas and stellar material about the AGN. Results show elliptical host galaxies with an orthogonal offset between the semi-major axis of the host galaxy and the secondary radio wings, which lends support to the hydrodynamical model. However, results also show circular host galaxies with radio wings, making the realignment scenario a more likely model to describe the formation of these X-shaped radio sources.
Springmann, A.; Cheung, C.
Radio-adaptive regimen attenuates features of cellular senescence
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Radio-Adaptive Regimen Attenuates Features of Cellular Senescence Albert Davalos Lawrence Berkeley National Laboratory Abstract Recent work from several laboratories suggest that...
Solar Radio Burst Effects on Global Positioning System Receivers .
??This thesis presents a series of studies investigating solar radio burst effects on Global Positioning System (GPS) receivers along with supporting instrumentation and analysis techniques.� (more)
Cerruti, Alessandro Paolo
Here Comes the Sun: NIST Radio Station WWVH in Hawaii ...
Science Conference Proceedings (OSTI)
... The sun is now a significant power source for ... Illustration of the solar array that powers NIST radio ... and connected to the local electrical grid last week ...
Optical frequency combs: From frequency metrology to optical ...
Science Conference Proceedings (OSTI)
... and to dis- tribute the load of the ... measurements of frequency ratios (ie, energy ratios), and ... accuracy or stability versus power consumption, cost, or ...
A giant radio jet ejected by an ultramassive black hole in a single-lobed radio galaxy
We report the discovery of a very unusual, highly asymmetric radio galaxy whose radio jet, the largest yet detected, emits strongly polarized synchrotron radiation and can be traced all the way from the galactic nucleus to the hot spot located ~440 kpc away. This jet emanates from an extremely massive black hole (>10^9 solar mass) and forms a strikingly compact radio lobe. No radio lobe is detected on the side of the counterjet, even though it is similar to the main jet in brightness up to a scale of tens of kiloparsecs. Thus, contrary to the nearly universal trend, the brightness asymmetry in this radio galaxy increases with distance from the nucleus. With several unusual properties, including a predominantly toroidal magnetic field, this Fanaroff-Riley type II megajet is an exceptionally useful laboratory for testing the role of magnetic field in jet stabilization and radio lobe formation.
Joydeep Bagchi; Gopal-Krishna; Marita Krause; Santosh Joshi
Computational strategy for modeling radio wave propagation in lossy circular waveguides
The propagation of radio waves in lossy waveguides and tunnels has been researched extensively for many years as can be seen in the detailed book by Wait. The mathematics used to model waveguides for communications is essentially the same as that needed to model radio frequency (RF) propagation in simple tunnels. The presence or lack of conductors inside a waveguide or tunnel is a key driver in the nature of the solutions one will find for a particular application, Delogne. When there are conductors passing through a waveguide or tunnel, the simplest modes of propagation are surface-guided waves following the conductor and typically enabling long-range transmission. A tunnel containing a core conductor can act rather like a coaxial cable, propagating waves at a nearly constant speed, regardless of frequency. Conversely, a tunnel or waveguide without internal conductors is subject to very different wave patterns, resulting in a much more complex propagation analysis. Holloway et al. presented an exhaustive study of RF propagation in circular structures embedded in lossy surroundings. The work of Holloway et al. is the basis for this paper, where we discuss application of their computational techniques and present refinements gleaned from our work on similar problems.
Moses, Ronald [Los Alamos National Laboratory; Cai, D Michael [Los Alamos National Laboratory
Barrier Immune Radio Communications for Demand Response
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94E 94E Barrier Immune Radio Communications for Demand Response F. Rubinstein, G. Ghatikar, J. Granderson, D. Watson Lawrence Berkeley National Laboratory P. Haugen, C. Romero Lawrence Livermore National Laboratory February 2009 DISCLAIMER This document was prepared as an account of work sponsored by the United States Government. While this document is believed to contain correct information, neither the United States Government nor any agency thereof, nor The Regents of the University of California, nor any of their employees, makes any warranty, express or implied, or assumes any legal responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe
RadioJockey: Mining Program Execution to Optimize Cellular Radio Usage Pavan K. Athivarapu1
dormancy is typically invoked with a fixed short inactivity timer (e.g., 3-5s), thereby reducing the energy. BACKGROUND AND MOTIVATION 2.1 Energy and Signaling Overhead During normal usage, a cellular radio switches costs. This has a major implication on the energy consumed by background applications that typically
Frequency Control Performance Measurement and Requirements
power systems operations could significantly influence primary frequency control.power system operations could not significantly influence primary frequency control.power system operations. Determination of frequency control
Illian, Howard F.
Science Conference Proceedings (OSTI)
A dense ionized cloud of gas has been recently discovered to be moving directly toward the supermassive black hole, Sgr A*, at the Galactic center. In 2013 June, at the pericenter of its highly eccentric orbit, the cloud will be approximately 3100 Schwarzschild radii from the black hole and will move supersonically through the ambient hot gas with a velocity of v{sub p} Almost-Equal-To 5400 km s{sup -1}. A bow shock is likely to form in front of the cloud and could accelerate electrons to relativistic energies. We estimate via particle-in-cell simulations the energy distribution of the accelerated electrons and show that the non-thermal synchrotron emission from these electrons might exceed the quiescent radio emission from Sgr A* by a factor of several. The enhanced radio emission should be detectable at GHz and higher frequencies around the time of pericentric passage and in the following months. The bow shock emission is expected to be displaced from the quiescent radio emission of Sgr A* by {approx}33 mas. Interferometric observations could resolve potential changes in the radio image of Sgr A* at wavelengths {approx}< 6 cm.
Narayan, Ramesh; Sironi, Lorenzo [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Oezel, Feryal [Department of Astronomy, University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721 (United States)
The Chandra X-ray Observatory is finding a large number of cavities in the X-ray emitting intra-cluster medium which often coincide with the lobes of the central radio galaxy. We propose high-resolution Sunyaev-Zel'dovich (SZ) observations in order to infer the still unknown dynamically dominating component of the radio plasma bubbles. This work calculates the thermal and relativistic SZ emission of different compositions of these plasma bubbles while simultaneously allowing for the cluster's kinetic SZ effect. As examples, we present simulations of an Atacama Large Millimeter Array (ALMA) observation and of a Green Bank Telescope (GBT) observation of the cores of the Perseus cluster and Abell 2052. We predict a 5 sigma detection of the southern radio bubble of Perseus in a few hours with the GBT and ALMA while assuming a relativistic electron population within the bubble. In Abell 2052, a similar detection would require a few ten hours with either telescope, the longer exposures mainly being the result of the higher redshift and the lower central temperature of this cluster. Future high-sensitivity multi-frequency SZ observations will be able to infer the energy spectrum of the dynamically dominating electron population in order to measure its temperature or spectral characteristics. This knowledge can yield indirect indications for an underlying radio jet model.
Christoph Pfrommer; Torsten A. Ensslin; Craig L. Sarazin
Source options for nuclear weapons identification system
Science Conference Proceedings (OSTI)
This report briefly presents the advantages and disadvantages of two timed sources of neutrons that can be used with the source-driven noise analysis method: (1) {sup 252}Cf in an ionization chamber and (2) an associated-particle sealed tube neutron generator (APSTNG). These sources can be used with frequency and time analysis methods for nuclear weapons identification, quality assurance in production, special nuclear materials assay, criticality safety, and provision of measured data for verification of neutron and gamma ray transport calculational methods. The advantages of {sup 252}Cf for a nuclear materials identification system are that it is simple, reliable, and small and that all source events are detected. The disadvantages are that it cannot be turned off, leads to small radiation doses in handling, and produces more than one neutron per fission event. The advantages of APSTNG are that it is directional, can be turned off, and has one particle per deuterium-tritium reaction. The disadvantages are that it is large and complicated compared to {sup 252}Cf.
Mihalczo, J.T.; Koehler, P.E.; Valentine, T.E.; Phillips, L.D.
Uniform power plant identification system
Science Conference Proceedings (OSTI)
In the seventies in the Federal Republic of Germany a uniform power plant identification system (Kraftwerks-Kennzeichen-System, KKS) was developed and introduced. It allows to keep the identification by all engineering disciplines from planning to waste management for any type of power plant. The paper explains the historical development, the structure and the application of this system.
Christiansen, W. (RWE Energie AG, Hauptverwaltung, Essen (DE)); Pannenbacker, K. (GABO mbH, Erlangen (DE)); Popp, H. (Siemens AG, Bereich Anlagentechnik, Erlangen (DE)); Seltmann, A. (ABB Kraftwerke AG, Mannheim (DE))
The Extended GMRT Radio Halo Survey I: New upper limits on radio halos and mini-halos
A fraction of galaxy clusters host diffuse radio sources called radio halos, radio relics and mini-halos. We present the sample and first results from the Extended GMRT Radio Halo Survey (EGRHS)- an extension of the GMRT Radio Halo Survey (GRHS, Venturi et al. 2007, 2008). It is a systematic radio survey of galaxy clusters selected from the REFLEX and eBCS X-ray catalogs . Analysis of GMRT data at 610/ 235/ 325 MHz on 12 galaxy clusters are presented. We report the detection of a newly discovered mini-halo in the cluster RXJ1532.9+3021 at 610 MHz. A small scale relic (~200 kpc) is suspected in the cluster Z348. We do not detect cluster-scale diffuse emission in 11 clusters. Robust upper limits on the detection of radio halo of size of 1 Mpc are determined. We also present upper limits on the detections of mini-halos in a sub-sample of cool-core clusters. The upper limits for radio halos and mini-halos are plotted in the radio power- X-ray luminosity plane and the correlations are discussed. Diffuse extended e...
Kale, R; Giacintucci, S; Dallacasa, D; Cassano, R; Brunetti, G; Macario, G; Athreya, R
Effective switching frequency multiplier inverter
A switching frequency multiplier inverter for low inductance machines that uses parallel connection of switches and each switch is independently controlled according to a pulse width modulation scheme. The effective switching frequency is multiplied by the number of switches connected in parallel while each individual switch operates within its limit of switching frequency. This technique can also be used for other power converters such as DC/DC, AC/DC converters.
Su, Gui-Jia (Oak Ridge, TN); Peng, Fang Z. (Okemos, MI)
Alternative Fuels Data Center: Renewable Identification Numbers
Alternative Fuels and Advanced Vehicles Data Center (EERE)
Renewable Renewable Identification Numbers to someone by E-mail Share Alternative Fuels Data Center: Renewable Identification Numbers on Facebook Tweet about Alternative Fuels Data Center: Renewable Identification Numbers on Twitter Bookmark Alternative Fuels Data Center: Renewable Identification Numbers on Google Bookmark Alternative Fuels Data Center: Renewable Identification Numbers on Delicious Rank Alternative Fuels Data Center: Renewable Identification Numbers on Digg Find More places to share Alternative Fuels Data Center: Renewable Identification Numbers on AddThis.com... More in this section... Federal State Advanced Search All Laws & Incentives Sorted by Type Renewable Identification Numbers RIN Format EPA uses the following format to determine RINs for each physical gallon of
Infrastructure Failure - Types and Frequency
U.S. Energy Information Administration (EIA)
Infrastructure Failure - Types and Frequency. Small events that have no impact on supplies Events that require supply/demand responses Events that result in a ...
Time and Frequency Division Homepage
Science Conference Proceedings (OSTI)
... Controlled ClocksTelephone TimeDivision HistoryFrequently Asked Questions (FAQ)Time and Frequency from A to Z: An illustrated glossaryA Walk ...
Science Conference Proceedings (OSTI)
We present Arecibo time-aligned, total intensity profiles for 46 pulsars over an unusually wide range of radio frequencies and multi-frequency, polarization-angle density diagrams, and/or polarization profiles for 57 pulsars at some or all of the frequencies 50, 111/130, 430, and 1400 MHz. The frequency-dependent dispersion delay has been removed in order to align the profiles for study of their spectral evolution, and wherever possible the profiles of each pulsar are displayed on the same longitude scale. Most of the pulsars within Arecibo's declination range that are sufficiently bright for such spectral or single pulse analysis are included in this survey. The calibrated single pulse sequences and average profiles are available by web download for further study.
Hankins, Timothy H. [Physics Department, New Mexico Tech, Socorro, NM 87801 (United States); Rankin, Joanna M. [Physics Department, University of Vermont, Burlington, VT 05401 (United States)], E-mail: email@example.com, E-mail: email@example.com
Dynamic frequency allocation in fractional frequency reused OFDMA networks
Science Conference Proceedings (OSTI)
This paper proposes a dynamic fractional frequency reused cell architecture that simplifies the problem of subcarrier allocation with frequency reuse in multicell OFDMA networks. The architecture divides the cell surface into two overlapping geographical ... Keywords: 3G, cellular networks, cross-layer adaptation, data networks, mobile communication systems, opportunistic scheduling, wireless communication
Syed Hussain Ali; Victor C. M. Leung
Radio Astronomy Software Defined Receiver Project
The paper describes a Radio Astronomy Software Defined Receiver (RASDR) that is currently under development. RASDR is targeted for use by amateurs and small institutions where cost is a primary consideration. The receiver will operate from HF thru 2.8 GHz. Front-end components such as preamps, block down-converters and pre-select bandpass filters are outside the scope of this development and will be provided by the user. The receiver includes RF amplifiers and attenuators, synthesized LOs, quadrature down converters, dual 8 bit ADCs and a Signal Processor that provides firmware processing of the digital bit stream. RASDR will interface to a user s PC via a USB or higher speed Ethernet LAN connection. The PC will run software that provides processing of the bit stream, a graphical user interface, as well as data analysis and storage. Software should support MAC OS, Windows and Linux platforms and will focus on such radio astronomy applications as total power measurements, pulsar detection, and spectral line studies.
Vacaliuc, Bogdan [ORNL; Leech, Marcus [Shirleys Bay Radio Astronomy Consortium; Oxley, Paul [Retired; Flagg, Richard [Retired; Fields, David [ORNL
Prof. F. Gorus Dienst Klinische Chemie en Radio-
Promotor Prof. F. Gorus Dienst Klinische Chemie en Radio- immunologie, UZ Brussel Vrije Universiteit Brussel Co-promotoren Dr. V. Maes Dienst Klinische Chemie en Radio- immunologie, UZ Brussel Vrije Varenbergh Dienst Pathologische Anatomie/EXPA Vrije Universiteit Brussel Prof. S. Sarre Farmaceutische chemie
Glineur, François
Searching for Transient Pulses with the ETA Radio Telescope
Science Conference Proceedings (OSTI)
Array-based, direct-sampling radio telescopes have computational and communication requirements unsuited to conventional computer and cluster architectures. Synchronization must be strictly maintained across a large number of parallel data streams, from ... Keywords: Direct sampling radio telescope array, FPGA cluster computing, RFI mitigation, signal dedispersion
C. D. Patterson; S. W. Ellingson; B. S. Martin; K. Deshpande; J. H. Simonetti; M. Kavic; S. E. Cutchin
Downlink Radio Resource Allocation for Multi-Cell OFDMA System
Science Conference Proceedings (OSTI)
This paper presents a radio resource control (RRC) scheme for OFDMA systems where dynamic resource allocation is realized at both a radio network controller (RNC) and base stations (BSs). The scheme is semi-distributed in the sense that the RRC decision ...
Guoqing Li; Hui Liu
General Interest NIST Time and Frequency Publications
Science Conference Proceedings (OSTI)
... Time and Frequency Users Manual A detailed ... Fundamentals of Time and Frequency An overview of ... Lombardi, The Mechatronics Handbook, 2001. ...
High Frequency Power Modulation - TRIMET Smelters Provide ...
Science Conference Proceedings (OSTI)
Presentation Title, High Frequency Power Modulation - TRIMET Smelters Provide Primary Control Power for Stabilizing the Frequency in the Electricity Grid.
Frequency Conversion of Entangled State
The quantum characteristics of sum-frequency process in an optical cavity with an input signal optical beam, which is a half of entangled optical beams, are analyzed. The calculated results show that the quantum properties of the signal beam can be maintained after its frequency is conversed during the intracavity nonlinear optical interaction. The frequency-conversed output signal beam is still in an entangled state with the retained other half of initial entangled beams. The resultant quantum correlation spectra and the parametric dependences of the correlations on the initial squeezing factor, the optical losses and the pump power of the sum-frequency cavity are calculated. The proposed system for the frequency conversion of entangled state can be used in quantum communication network and the calculated results can provide direct references for the design of experimental systems.
Aihong Tan; Xiaojun Jia; Changde Xie
Management of Oak Ridge Radio Transition Projects, DOE/IG-0653...
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
Sites Power Marketing Administration Other Agencies You are here Home Management of Oak Ridge Radio Transition Projects, DOEIG-0653 Management of Oak Ridge Radio Transition...
Contribution au d�veloppement de tag RFID UHF et Microondes sur mat�riaux plastiques.
??La RFID (RadioFrequency Identification) est une technologie d'identification int�lligente qui connait de nombreux d�veloppements car ses domaines d'applications vont de la tra�abilit� de produits et� (more)
B�chevet, Delphine
Ultrawide Bandwidth RFID: The Next Generation?
Future advanced radio-frequency identification (RFID) systems are expected to provide both identification and high-definition localization of objects with improved reliability and security while maintaining low power ...
Dardari, Davide
PKS0347+05: a radio-loud/radio-quiet double AGN system triggered in a major galaxy merger
We present optical, infrared and radio observations of the powerful FRII radio source PKS0347+05 (z=0.3390), and demonstrate that it is a rare example of a radio-loud/radio-quiet double AGN system, comprising a weak line radio galaxy (WLRG) separated by 25 kpc (in projection) from a Seyfert 1 nucleus at the same redshift. Our deep Gemini optical images show a highly disturbed morphology, with a warped dust lane crossing through the halo and nuclear regions of the radio galaxy host, tidal tails, and a bridge connecting the radio galaxy to the Seyfert 1 nucleus. Spectral synthesis modelling of our Gemini optical spectrum of the radio galaxy shows evidence for a reddened young stellar population of age <100 Myr. Further evidence for recent star formation activity in this source is provided by the detection of strong PAH features in mid-IR Spitzer/IRS spectra. Together, these observations support a model in which both AGN have been triggered simultaneously in a major galaxy merger. However, despite the presenc...
Tadhunter, C; Morganti, R; Holt, J; Rose, M; Dicken, D; Inskip, K
Deep radio surveys show a population of very red counterparts of microjansky radio sources, which are unidentified to I = 25 in ground based images and I = 28.5 in the Hubble Deep Field. This population of optically faint radio sources, which comprises about 20% of the microjansky radio samples, may be dust enshrouded starburst galaxies, extreme redshift or dust reddened AGN, or due to displaced radio lobes. Even deeper radio surveys, which will be made possible by next generation radio telescopes such as the Expanded VLA or the Square Kilometer Array, will reach to nanojansky levels which may be dominated by this new population, but only if special care is taken to achieve high angular resolution and dynamic range better than 60 dB. This will reuire array dimensions up to 1000 km to achieve confusion limited performance at 1.4 GHz and up to 10,000 km at 300 MHz. But, even then, the ability to study individual nanojanksy radio sources may be limited by the finite extent of the sources and consequential blending of their images.
K. I. Kellermann; E. A. Richards
Science Conference Proceedings (OSTI)
This article highlights the influence that new ICTs and Computer Mediated Communication is having on the newsroom cultures among community radio journalists in Africa, especially the use of mobile phones and the internet. The discussion is based on findings ... Keywords: Community radio, Glocal, Journalism practice, Mobile phones, New ICTs, New media, Participatory communication
Goretti Linda Nassanga; Linje Manyozo; Claudia Lopes
Noise Reduction with Microphone Arrays for Speaker Identification
Reducing acoustic noise in audio recordings is an ongoing problem that plagues many applications. This noise is hard to reduce because of interfering sources and non-stationary behavior of the overall background noise. Many single channel noise reduction algorithms exist but are limited in that the more the noise is reduced; the more the signal of interest is distorted due to the fact that the signal and noise overlap in frequency. Specifically acoustic background noise causes problems in the area of speaker identification. Recording a speaker in the presence of acoustic noise ultimately limits the performance and confidence of speaker identification algorithms. In situations where it is impossible to control the environment where the speech sample is taken, noise reduction filtering algorithms need to be developed to clean the recorded speech of background noise. Because single channel noise reduction algorithms would distort the speech signal, the overall challenge of this project was to see if spatial information provided by microphone arrays could be exploited to aid in speaker identification. The goals are: (1) Test the feasibility of using microphone arrays to reduce background noise in speech recordings; (2) Characterize and compare different multichannel noise reduction algorithms; (3) Provide recommendations for using these multichannel algorithms; and (4) Ultimately answer the question - Can the use of microphone arrays aid in speaker identification?
Cohen, Z
Probabilistic image reconstruction for radio interferometers
We present a novel, general-purpose method for deconvolving and denoising images from gridded radio interferometric visibilities using Bayesian inference based on a Gaussian process model. The method automatically takes into account incomplete coverage of the uv-plane and mode coupling due to the beam. Our method uses Gibbs sampling to efficiently explore the full posterior distribution of the underlying signal image given the data. We use a set of widely diverse mock images with a realistic interferometer setup and level of noise to assess the method. Compared to results from a proxy for the CLEAN method we find that in terms of RMS error and signal-to-noise ratio our approach performs better than traditional deconvolution techniques, regardless of the structure of the source image in our test suite. Our implementation scales as O(np log np), provides full statistical and uncertainty information of the reconstructed image, requires no supervision, and provides a robust, consistent framework for incorporating...
Sutter, P M; McEwen, Jason D; Bunn, Emory F; Karakci, Ata; Korotkov, Andrei; Timbie, Peter; Tucker, Gregory S; Zhang, Le
MicrobeWorld Radio and Communications Initiative
Science Conference Proceedings (OSTI)
MicrobeWorld is a 90-second feature broadcast daily on more than 90 public radio stations and available from several sources as a podcast, including www.microbeworld.org. The feature has a strong focus on the use and adapatbility of microbes as alternative sources of energy, in bioremediation, their role in climate, and especially the many benefits and scientific advances that have resulting from decoding microbial genomes. These audio features are permanantly archived on an educational outreach site, microbeworld.org, where they are linked to the National Science Education Standards. They are also being used by instructors at all levels to introduce students to the multiple roles and potential of microbes, including a pilot curriculum program for middle-school students in New York.
Barbara Hyde
Science Conference Proceedings (OSTI)
This study looks at the perceived ability of components of IT infrastructure integration and supply chain process integration to predict specific radio frequency identification (RFID) system deployment outcomes-exploration, exploitation, operational ... Keywords: Data consistency, Exploitation, Exploration, IT infrastructure, Information sharing, Market knowledge creation, Operational efficiency, Radio frequency identification (RFID), Supply chain business processes, Supply chain management
Rebecca Angeles
The state of RFID for effective baggage tracking in the airline industry
Science Conference Proceedings (OSTI)
This article examines the state of Radio Frequency Identification (RFID) as a solution to the problem of tracking baggage within the commercial aviation industry. The benefits and drawbacks of RFID are examined. The cost of RFID tags is still ... Keywords: Delta Airlines, RFID, airline industry, baggage handling, baggage tracking, customer service, radio frequency identification
Peter D. DeVries
Science Conference Proceedings (OSTI)
Radio frequency identification (RFID) technology dramatically increases the ability of the organization to acquire a vast array of data about the location and properties of any entity that can be physically tagged ... Keywords: Business value, Diffusion of innovations, IT impacts, Information technology, RFID, Radio frequency identification, Technology adoption
John Curtin; Robert J. Kauffman; Frederick J. Riggins
Surveillance Guides - Identification of Hazards
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
Identification of Hazards Identification of Hazards 1.0 Objective The objective of this surveillance is to evaluate the effectiveness of the contractor's hazards identification programs. Surveillance activities encompass maintenance and implementation of safety basis documentation (SARs, ISBs, BIOs, JCOs, HASPs etc) as well as activity level hazards identification via JHAs, AJHAs, JSAs etc.) 2.0 References 2.1 DOE 4330.4B Maintenance Management Program 2.2 48 CFR 1970 Department of Energy Acquisition Regulations 2.3 DOE O 5480.21, Unreviewed Safety Questions 2.4 DOE O 5480.23, Nuclear Safety Analysis Reports 3.0 Requirements Implemented This surveillance verifies implementation of guiding principle #5 and core value #2 as specified in 48 CFR 1970.5204-2 (b) (5) and (c) (2) respectively. Additionally, it verifies implementation of
Identification of Anonymous Endogenous Interactions
Introduction In theoretical studies of social interactions, we hypothesize a process and seek to deduce the implied outcomes. In inferential studies, we face an inverse logical problem. Given observations of outcomes and maintained assumptions, we seek to deduce the actual process generating the observations. Econometricians have long found it useful to separate inferential problems into statistical and identification components (see Koopmans, 1949). Studies of identification seek to characterize the conclusions that could be drawn if one could use a given sampling process to obtain an unlimited number of observations. Studies of statistical inference seek to characterize the generally weaker conclusions that can be drawn from a finite number of observations. Analysis of identification logically comes first. Negative identification findings imply that statistical inference is fruitless: it makes no sense to try to use a sample of finite size to infer something that could not be learned
Charles F. Manski
Frequency regulator for synchronous generators
The present invention is directed to a novel frequency regulator which controls a generator output frequency for variations in both the input power to the generator and the power supplied to an uncontrolled external load. The present invention further includes over current and current balance protection devices which are relatively inexpensive to manufacture, which may be encapsulated to provide protection from the operating environment and which respond more quickly than previously known electromechanical devices.
Karlicek, Robert F. (1920 Camino Centroloma, Fullerton, CA 92633)
Frequency regulator for synchronous generators
The present invention is directed to a novel frequency regulator which controls a generator output frequency for variations in both the input power to the generator and the power supplied to an uncontrolled external load. The present invention further includes over current and current balance protection devices which are relatively inexpensive to manufacture, which may be encapsulated to provide protection from the operating environment and which respond more quickly than previously known electromechanical devices. 11 figs.
Karlicek, R.F.
Forthcoming occultations of astrometric radio sources by planets
Astrometric observations of the radio source occultations by solar system bodies may be of large interest for testing gravity theories, dynamical astronomy, and planetary physics. In this paper, we present an updated list of the occultations of astrometric radio sources by planets expected in the nearest years. Such events, like the solar eclipses, generally speaking, can be only observed in a limited region. The map of the shadow path is provided for the events occurred in regions with several VLBI stations and hence the most interesting for radio astronomy experiments.
L'vov, Victor; Tsekmeister, Svetlana
It has been suggested that type II radio bursts are due to energetic electrons accelerated at coronal shocks. Radio observations, however, have poor or no spatial resolutions to pinpoint the exact acceleration locations of these electrons. In this paper, we discuss a promising approach to infer the electron acceleration location by combining radio and white light observations. The key assumption is to relate specific morphological features (e.g., spectral bumps) of the dynamic spectra of type II radio bursts to imaging features (e.g., coronal mass ejection (CME) going into a streamer) along the CME (and its driven shock) propagation. In this study, we examine the CME-streamer interaction for the solar eruption dated on 2003 November 1. The presence of spectral bump in the relevant type II radio burst is identified, which is interpreted as a natural result of the shock-radio-emitting region entering the dense streamer structure. The study is useful for further determinations of the location of type II radio burst and the associated electron acceleration by CME-driven shock.
Feng, S. W.; Chen, Y.; Kong, X. L.; Li, G.; Song, H. Q. [Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, School of Space Science and Physics, Shandong University at Weihai, Weihai 264209 (China); Feng, X. S. [SIGMA Weather Group, State Key laboratory for Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190 (China); Liu Ying, E-mail: email@example.com [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States)
Apparatus configured for identification of a material and method of identifying a material
The present invention relates to an apparatus configured for identification of a material and method of identifying a material. One embodiment of the present invention provides an apparatus configured for identification of a material including a first region configured to receive a first sample and output a first spectrum responsive to exposure of the first sample to radiation; a signal generator configured to provide a reference signal having a reference frequency and a modulation signal having a modulation frequency; a modulator configured to selectively modulate the first spectrum using the modulation signal according to the reference frequency; a second region configured to receive a second sample and output a second spectrum responsive to exposure of the second sample to the first spectrum; and a detector configured to detect the second spectrum.
Slater, John M. (Idaho Falls, ID); Crawford, Thomas M. (Idaho Falls, ID); Frickey, Dean A. (Idaho Falls, ID)
DOE Emergency Special Needs Self-Identification Form | Department...
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
Emergency Special Needs Self-Identification Form DOE Emergency Special Needs Self-Identification Form Emergency Special Needs Self-Identification Form DOE Emergency Special Needs...
Production and identification of the ion-temperature-gradient instability
In order to produce and study the ion-temperature-gradient instability, the Columbia Linear Machine has been modified to yield a peaked ion temperature and flattish density profiles. Under these conditions the parameter {eta}{sub {ital i}} (={ital d} ln{ital T}{sub {ital i}}/{ital d} ln{ital N}) exceeded the critical value and a strong instability has been observed. Further identification has been based on observation of the azimuthal and axial wavelengths, and the real frequency, appropriate for the mode.
Sen, A.K.; Chen, J.; Mauel, M. (Plasma Research Laboratory, Columbia University, New York, New York 10027 (US))
On Digital Radio Receiver Performance in Electromagnetic Interference Environments
adiated emission from electronic equipment, co-located to a digital radio receiver, can affect receiving performance. It is therefore of great importance that this undesired emission be considered in the early design phase of a system containing radio equipment. For this purpose, methods to estimate the performance degradation on digital radio receivers in such environment must be available. From a military point of view, such methods are necessary for at least two important situations; 1) The communication system is not subject to interference from hostile jammers. In this case, undesired electromagnetic interference will decrease the operating range of the radio link. 2) The communication system is subject to interference from hostile jammers. In this case, the ability to withstand jamming is degraded by the undesired interference, as the latter degrades the signal protection devices in the communication system. A tactical consequence of this is that the jammer can obtain the same ...
Peter Stenumgaard; Peter Stenumgaard; Isrn Kth/rst/r--/ --se
NIST Physicists Turn to Radio Dial for Finer Atomic ...
Science Conference Proceedings (OSTI)
... Just as it is easier to improve reception on a home radio by both ... The new work shows that, near magnetic field values that have a big effect on the ...
Mobile radio slotted ALOHA with capture and diversity
Science Conference Proceedings (OSTI)
In this paper, the slotted ALOHA protocol in a mobile radio environment, in the presence of Ricean fading, two-fold antenna diversity and multiple reception capability, is considered. The capture probabilities and the average throughput are computed, ...
Michele Zorzi
Mapping GPS Radio Occultation Data by Bayesian Interpolation
Science Conference Proceedings (OSTI)
Bayesian interpolation for mapping GPS radio occultation data on a sphere is explored and its performance evaluated. Bayesian interpolation is ideally suited to the task of fitting data randomly and nonuniformly distributed with unknown error ...
Stephen S. Leroy; Chi O. Ao; Olga Verkhoglyadova
Impacts of Ice Clouds on GPS Radio Occultation Measurements
Science Conference Proceedings (OSTI)
Mathematical solutions accounting for the effects of liquid and ice clouds on the propagation of the GPS radio signals are first derived. The percentage contribution of ice water content (IWC) to the total refractivity increases linearly with the ...
X. Zou; S. Yang; P. S. Ray
Extensive Air Shower Radio Detection: Recent Results and Outlook
A prototype system for detecting radio pulses associated with extensive cosmic ray air showers is described. Sensitivity is compared with that in previous experiments, and lessons are noted for future studies.
Jonathan L. Rosner; Denis A. Suprun
COSMIC Radio Occultation Processing: Cross-Center Comparison and Validation
Science Conference Proceedings (OSTI)
A radio occultation data processing system (OCC) was developed for numerical weather prediction and climate benchmarking. The data processing algorithms use the well-established Fourier integral operator�based methods, which ensure a high accuracy ...
Michael E. Gorbunov; A. V. Shmakov; Stephen S. Leroy; Kent B. Lauritsen
Microsoft Word - CF-Radio-Comm-Upgrades-CX.doc
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
(T13N R34E SEC14) The proposed work at this site includes installing a 150-foot tall radio tower and antenna system, 10x25-foot communications building, 10x15-foot...
Amplified radio emission from cosmic ray air showers in thunderstorms
Cosmic ray air showers produce radio emission, consisting in large part of geosynchrotron emission. Since the radiation mechanism is based on particle acceleration, the atmospheric electric field can play an important role. Especially inside thunderclouds large electric fields can be present. We examine the contribution of an electric field to the emission mechanism theoretically and experimentally. Two mechanisms of amplification of radio emission are considered: the acceleration radiation of the shower particles and the radiation from the current that is produced by ionization electrons moving in the electric field. We selected and evaluated LOPES data recorded during thunderstorms, periods of heavy cloudiness and periods of cloudless weather. We find that during thunderstorms the radio emission can be strongly enhanced. No amplified pulses were found during periods of cloudless sky or heavy cloudiness, suggesting that the electric field effect for radio air shower measurements can be safely ignored during non-thunderstorm conditions.
Stijn Buitink; for the LOPES collaboration
Press Room - Radio - U.S. Energy Information Administration (EIA)
U.S. Energy Information Administration (EIA) Indexed Site
Press Room Press Room Glossary › FAQS › Overview Press Releases Testimony Presentations Radio Events Radio Spots Ready-to-broadcast news stories. Transcripts provided so radio spots can be re-recorded in whole or in part. Residential heating oil prices virtually unchanged mp3 Date: December 18, 2013 Description: The average retail price for home heating oil fell 4-tenths of a penny from a week ago to $3.95 per gallon. That's down 8-tenths of a penny from a year ago, based on the residential heating fuel survey by the U.S. Energy Information Administration. Heating oil prices in the New England region rose 3.92 per gallon, up 3-tenths of a cent from last week, and up 3 cents from a year ago. Contact/Author: Amerine Woodyard, 202-586-1256 Transcript: http://www.eia.gov/radio/transcript/heating_oil_prices_12182013.pdf
Microsoft Word - CX_MerrittRadioStationUpgrade_2013.docx
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
8, 2013 8, 2013 REPLY TO ATTN OF: KEC-4 SUBJECT: Environmental Clearance Memorandum Ben Deschuytter Project Manager - TEP-CSB-1 Proposed Action: Merritt Radio Station Upgrade Categorical Exclusions Applied (from Subpart D, 10 C.F.R. Part 1021): B1.19 Microwave, meteorological, and radio towers Location: Winton, Chelan County, WA Township 26N, Range 16E, and Section 2 Proposed by: Bonneville Power Administration (BPA) Description of the Proposed Action: BPA plans to upgrade its Merritt Radio Station in the Wenatchee River Ranger District of the Okanogan-Wenatchee National Forest (USFS). The proposed radio station upgrade would replace the existing communication building, electrical service, and propane tank with a new building and propane tank in adjacent locations on the
RSTN (Radio Solar Telescope Network) observations of the 16 February 1984 cosmic-ray flare
The radio Solar Telescope Network (RSTN) are located at Sagamore Hill (Massachusetts), Palehua (Hawaii), and Learmonth (Australia). A fourth site at San Vito (Italy) will begin making observations in 1986. The RSTN stations monitor the quiet and disturbed Sun at eight fixed frequencies logarithmically spaced from 245-15400 MHz. The radiometer patrols are operated from sunrise to sunset. Data are stored on magnetic tape with 1 second time resolution and archived at the World Data Center A in Boulder for dissemination to the scientific community. The Palehua site became operational in July 1980, followed by Learmonth in August 1980, and Sagamore Hill in October 1981. Thus digitized radiometer observations of the Sun are available for a significant fraction of the maximum phase of solar cycle 21.
Cliver, E.W.; Gentile, L.C.; Wells, G.D.
Host Galaxies of X-Shaped Radio Sources
The majority of radiation from galaxies containing active galactic nuclei (AGNs) is emitted not by the stars composing the galaxy, but from an active source at the galactic center, most likely a supermassive black hole. Of particular interest are radio galaxies, the active galaxies emitting much of their radiation at radio wavelengths. Within each radio galaxy, an AGN powers a pair of collimated jets of relativistic particles, forming a pair of giant lobes at the end of the jets and thus giving a characteristic double-lobed appearance. A particular class of radio galaxies have an ''X''-shaped morphology: in these, two pairs of lobes appear to originate from the galactic center, producing a distinctive X-shape. Two main mechanisms have been proposed to explain the X-shape morphology: one being through the merger of a binary supermassive black hole system and the second being that the radio jets are expanding into an asymmetric medium. By analyzing radio host galaxy shapes, we probe the distribution of the stellar mass to compare the differing model expectations regarding the distribution of the surrounding gas and stellar material about the AGN.
Springmann, Alessondra; /Wellesley Coll. /SLAC
Minkowski's Object: A Starburst Triggered by a Radio Jet, Revisited
We present neutral hydrogen, ultraviolet, optical and near-infrared imaging, as well as optical spectroscopic observations of Minkowski's Object (MO), a star forming system at the end of a radio jet associated with NGC541 at the center of a cluster of galaxies, Abell 194. The observations strengthen the evidence, first presented in 1985, that MO is a small, peculiar galaxy in which the star formation has been triggered by the radio jet. Key new results are the discovery of a double H I cloud with a mass of 4.9 x 10{sup 8} M{sub {circle_dot}} straddling the radio jet downstream from MO at the location where the jet changes direction and decollimates; a strong detection of MO at near- and far-UV wavelengths and in H{alpha}, both of which also show a double structure; and what appear to be numerous H II regions and associated clusters in MO. The UV morphology of MO along the radio jet resembles the radio-aligned, rest-frame UV morphologies seen in many high redshift radio galaxies, which are also thought to be caused by jet-induced star formation. The UV, optical, and near-IR data show that the stellar population is dominated by a 7.5Myr-old instantaneous burst, with a total stellar mass of 1.9 x 10{sup 7} M{sub {circle_dot}}.
Croft, S; van Breugel, W; de Vries, W; Dopita, M; Martin, C; Morganti, R; Neff, S; Oosterloo, T; Schiminovich, D; Stanford, S A; van Gorkom, J
The evolution of symmetric extragalactic radio sources can be characterized by four distinct growth stages of the radio luminosity versus size of the source. The interaction of the jet with the ambient medium results in the formation and evolution of sources with non-standard (flaring) morphology. In addition, cessation or restarting of the jet power and obstruction of the jet will also result in distinct morphological structures. The radio source population may thus be classified in morphological types that indicate the prevailing physical processes. Compact symmetric objects (CSOs) occupy the earliest evolutionary phase of symmetric radio sources and their dynamical behavior is fundamental for any further evolution. Analysis of CSO dynamics is presented for a sample of 24 CSOs with known redshift and hotspot separation velocity and with a large range of radio power. Observables such as radio power, separation between two hotspots, hotspot separation velocity, and kinematic age of the source are found to be generally consistent with the self-similar predictions for individual sources that reflect the varying density structure of the ambient interstellar medium. Individual sources behave different from the group as a whole. The age and size statistics confirm that a large fraction of CSOs does not evolve into extended doubles.
An Tao [Shanghai Astronomical Observatory, Chinese Academy of Sciences, 200030 Shanghai (China); Baan, Willem A., E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com [ASTRON, P.O. Box 2, 7990-AA Dwingeloo (Netherlands)
Thunderstorm Observations by Air-Shower Radio Antenna Arrays
Relativistic, charged particles present in extensive air showers lead to a coherent emission of radio pulses which are measured to identify the shower initiating high-energy cosmic rays. Especially during thunderstorms, there are additional strong electric fields in the atmosphere, which can lead to further multiplication and acceleration of the charged particles and thus have influence on the form and strength of the radio emission. For a reliable energy reconstruction of the primary cosmic ray by means of the measured radio signal it is very important to understand how electric fields affect the radio emission. In addition, lightning strikes are a prominent source of broadband radio emissions that are visible over very long distances. This, on the one hand, causes difficulties in the detection of the much lower signal of the air shower. On the other hand the recorded signals can be used to study features of the lightning development. The detection of cosmic rays via the radio emission and the influence of s...
Apel, W D; B�hren, L; Bekk, K; Bertaina, M; Biermann, P L; Bl�mer, J; Bozdog, H; Brancus, I M; Buchholz, P; Buitink, S; Cantoni, E; Chiavassa, A; Daumiller, K; de Souza, V; Doll, P; Ender, M; Engel, R; Falcke, H; Finger, M; Fuhrmann, D; Gemmeke, H; Grupen, C; Haungs, A; Heck, D; H�randel, J R; Horneffer, A; Huber, D; Huege, T; Isar, P G; Kampert, K -H; Kang, D; Kr�mer, O; Kuijpers, J; Link, K; Luczak, P; Ludwig, M; Mathes, H J; Melissas, M; Morello, C; Nehls, S; Oehlschl�ger, J; Palmieri, N; Pierog, T; Rautenberg, J; Rebel, H; Roth, M; R�hle, C; Saftoiu, A; Schieler, H; Schmidt, A; Schr�der, F G; Sima, O; Toma, G; Trinchero, G C; Weindl, A; Wochele, J; Wommer, M; Zabierowski, J; Zensus, J A; 10.1016/j.asr.2011.06.003
KTFC Midwest Bible Radio Wind Farm | Open Energy Information
KTFC Midwest Bible Radio Wind Farm KTFC Midwest Bible Radio Wind Farm Jump to: navigation, search Name KTFC Midwest Bible Radio Wind Farm Facility KTFC Midwest Bible Radio Sector Wind energy Facility Type Small Scale Wind Facility Status In Service Owner KTFC Midwest Bible Radio Energy Purchaser KTFC Midwest Bible Radio Location IA Coordinates 42.4837°, -96.3068° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":42.4837,"lon":-96.3068,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}
Investigating the EGRET-radio galaxies link with INTEGRAL: the case of 3EG J1621+8203 and NGC 6251
The analysis of an INTEGRAL AO2 observation of the error contours of the EGRET source 3EG J1621+8203 is presented. The only source found inside the error contours for energies between 20 and 30 keV at 5 sigma detection significance is the FR I radio galaxy NGC 6251. This supports the identification of NGC 6251 with 3EG J1621+8203. The observed flux is higher and softer than observed in the past, but consistent with a variable blazar-like spectral energy distribution.
L. Foschini; M. Chiaberge; P. Grandi; I. A. Grenier; M. Guainazzi; W. Hermsen; G. G. C. Palumbo; J. Rodriguez; S. Chaty; S. Corbel; G. Di Cocco; L. Kuiper; G. Malaguti
We discuss an intriguing type II radio burst that occurred on 2011 March 27. The dynamic spectrum was featured by a sudden break at about 43 MHz on the well-observed harmonic branch. Before the break, the spectrum drifted gradually with a mean rate of about -0.05 MHz s{sup -1}. Following the break, the spectrum jumped to lower frequencies. The post-break emission lasted for about 3 minutes. It consisted of an overall slow drift which appeared to have a few fast-drift sub-bands. Simultaneous observations from the Solar TErrestrial RElations Observatory and the Solar Dynamics Observatory were also available and are examined for this event. We suggest that the slow-drift period before the break was generated inside a streamer by a coronal eruption driven shock, and the spectral break as well as the relatively wide spectrum after the break is a consequence of the shock crossing the streamer boundary where density drops abruptly. It is suggested that this type of radio bursts can be taken as a unique diagnostic tool for inferring the coronal density structure, as well as the radio-emitting source region.
Kong, X. L.; Chen, Y.; Li, G.; Feng, S. W.; Song, H. Q.; Jiao, F. R. [Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, School of Space Science and Physics, Shandong University at Weihai, Weihai 264209 (China); Guo, F., E-mail: firstname.lastname@example.com [Department of Planetary Sciences and Lunar and Planetary laboratory, University of Arizona, Tucson, AZ 85721 (United States)
Power and Energy Measurements Low Frequency
Science Conference Proceedings (OSTI)
... Power and Energy Measurements, Low-Frequency. Rate our Services. ... Power and Energy Measurements, Low-Frequency (56200C-56202C). ...
Science Conference Proceedings (OSTI)
... noise terms are the result of environmental changes affecting ... respond to changes in environment, so this ... is probably of broadest concern, but some ...
Identification of rotordynamic forces in a flexible rotor system using magnetic bearings
Methods are presented for parameter identification of an annular gas seal on a flexiblerotor test rig. Dynamic loads are applied by magnetic bearings (MBs) that support the rotor. MB forces are measured using fiber-optic strain gauges that are bonded to the poles of the MBs. In addition to force and position measurements, a finite element (FE) rotor model is required for the identification algorithms. The FE rotor model matches free-free characteristics of the test rotor. The addition of smooth air seals to the system introduces stiffness and damping terms for identification that are representative of reaction forces in turbomachines. Tests are performed to experimentally determine seal stiffness and damping coefficients for different running speeds and preswirl conditions. Stiffness and damping coefficients are determined using a frequency domain identification method. This method uses an iterative approach to minimize error between theoretical and experimental transfer functions. Several time domain approaches are also considered; however, these approaches do not produce valid identification results. Stiffness coefficients are measured using static test results and an MB current and position based model. Test results produce seal coefficients with low uncertainties for the frequency domain identification method. Static test uncertainties are an order of magnitude larger, and time domain attempts fail to produce sealIn addition to the primary identification research, an investigation of the relationships between MB force, strain, and magnetic field is conducted. The magnetic field of an MB is modeled using commercial FE software. The magnetic field model is used to predict strain measurements for quasi-static test conditions. The strain predictions are compared with experimental strain measurements. Strain predictions agree with experimental measurements, although strain is typically over-predicted. coefficient measurements.
Zutavern, Zachary Scott
Frequency Dependence in Forecast Skill
Science Conference Proceedings (OSTI)
A method is proposed to calculate measures of forecast skill for high, medium and low temporal frequency variations in the atmosphere. This method is applied to a series of 128 consecutive 1 to 10-day forecasts produced at NMC with their ...
H. M. van Den Dool; Suranjana Saha
Frequency agile optical parametric oscillator
The frequency agile OPO device converts a fixed wavelength pump laser beam to arbitrary wavelengths within a specified range with pulse to pulse agility, at a rate limited only by the repetition rate of the pump laser. Uses of this invention include Laser radar, LIDAR, active remote sensing of effluents/pollutants, environmental monitoring, antisensor lasers, and spectroscopy.
Velsko, Stephan P. (Livermore, CA)
Frequency agile optical parametric oscillator
The frequency agile OPO device converts a fixed wavelength pump laser beam to arbitrary wavelengths within a specified range with pulse to pulse agility, at a rate limited only by the repetition rate of the pump laser. Uses of this invention include Laser radar, LIDAR, active remote sensing of effluents/pollutants, environmental monitoring, antisensor lasers, and spectroscopy. 14 figs.
Velsko, S.P.
Investigation of Multi-Frequency Power Transmission and System
This dissertation presents a new power system transmission concept based on frequency selectivity named Multi-Frequency Power System (MFPS). This system allows for selective power transmission among terminals in an interconnected system, and is enabled by power electronic technology. The dissertation starts with a presentation of some of the challenges faced by modern power systems, and includes a description of various power system technologies developed in an attempt to solve them. Then, our proposed solution is presented as an alternative to electric power transmission, and the fundamental concepts are explained. A version of the MFPS is developed, which has relevance to the problem of renewable sources integration. This AC DC Power System is further explored, and the topology of the system and the converters is presented, as well as the control techniques used in its operation. The dissertation also presents a performance study of the AC DC system, which was done in Simulink, and it demonstrates the robustness of the system under various dynamic and fault conditions. Finally, a summary of the work is given in the last section of the dissertation. The contributions of our research to the state of technology are discussed. These contributions include: the demonstration of power selectivity based on frequency identification, the development of a novel transmission system and a AC DC integrated implementation of it, and the development of a control and converter that enables selective power transmission. Also, some of the most relevant future research initiatives related to this topic are presented.
Barazarte Conte, Ronald
Radio emission from shell-type supernova remnants
The evolution of the radio emission of shell-type Supernova remnants (SNRs) is modeled within the framework of the simple and commonly used assumptions that the mechanism of diffusive shock acceleration (DSA) is responsible for generating radio emitting electrons and that the magnetic field is the typical interstellar field compressed at the shock. It is considered that electrons are injected into the mechanism in test-particle regime directly from the high energy tail of the downstream Maxwellian distribution function. The model can be applied to most of the observed SNRs. It is shown that the model successfully explains the many averaged observational properties of evolved shell-type SNRs. In particular, the radio surface brightness ($\\Sigma$) evolves with diameter as $\\sim D^{-(0.3 \\div 0.5)}$, while the bounding shock is strong (Mach number is ${\\mathcal M} \\geq10$), followed by steep decrease (steeper than $\\sim D^{-4.5}$) for ${\\cal M} environmental parameters strongly reduce the usefulness of $\\Sigma - D$ relations as a tool for determining the distances to SNRs. The model predicts no radio emission from SNRs in the late radiative stage of evolution and the existence of radio-quiet but relatively active SNRs is possible. Our model easily explains very large-diameter radio sources such as the Galactic Loops and the candidates for Hypernova radio remnants. The model predicts that most of the observed SNRs are located in a tenuous phase of the ISM. From the comparison of the model results with the statistics of evolved shell-type SNRs, we were able to estimate the fraction of electrons accelerated from the thermal pool in the range $(3\\div 11) \\times 10^{- 4}$.
Abdul Asvarov
Numerical relativity simulations predict that coalescence of supermassive black hole (SMBH) binaries leads not only to a spin flip but also to a recoiling of the merger remnant SMBHs. In the literature, X-shaped radio sources are popularly suggested to be candidates for SMBH mergers with spin flip of jet-ejecting SMBHs. Here we investigate the spectral and spatial observational signatures of the recoiling SMBHs in radio sources undergoing black hole spin flip. Our results show that SMBHs in most spin-flip radio sources have mass ratio q {approx}> 0.3 with a minimum possible value q{sub min} {approx_equal} 0.05. For major mergers, the remnant SMBHs can get a kick velocity as high as 2100 km s{sup -1} in the direction within an angle {approx}< 40 Degree-Sign relative to the spin axes of remnant SMBHs, implying that recoiling quasars are biased to be with high Doppler-shifted broad emission lines while recoiling radio galaxies are biased to large apparent spatial off-center displacements. We also calculate the distribution functions of line-of-sight velocity and apparent spatial off-center displacements for spin-flip radio sources with different apparent jet reorientation angles. Our results show that the larger the apparent jet reorientation angle is, the larger the Doppler-shifting recoiling velocity and apparent spatial off-center displacement will be. We investigate the effects of recoiling velocity on the dust torus in spin-flip radio sources and suggest that recoiling of SMBHs would lead to 'dust-poor' active galactic nuclei. Finally, we collect a sample of 19 X-shaped radio objects and for each object give the probability of detecting the predicted signatures of recoiling SMBH.
Liu, F. K.; Wang Dong [Department of Astronomy, Peking University, 100871 Beijing (China); Chen Xian, E-mail: email@example.com [Kavli Institute for Astronomy and Astrophysics, Peking University, 100871 Beijing (China)
Recoiling Supermassive Black Holes in Spin-flip Radio Galaxies
Numerical relativity simulations predict that coalescence of supermassive black hole (SMBH) binaries not only leads to a spin flip but also to a recoiling of the merger remnant SMBHs. In the literature, X-shaped radio sources are popularly suggested to be candidates for SMBH mergers with spin flip of jet-ejecting SMBHs. Here we investigate the spectral and spatial observational signatures of the recoiling SMBHs in radio sources undergoing black hole spin flip. Our results show that SMBHs in most spin-flip radio sources have mass ratio $q\\ga 0.3$ with a minimum possible value $q_{\\rm min} \\simeq 0.05$. For major mergers, the remnant SMBHs can get a kick velocity as high as $2100 km s^{-1}$ in the direction within an angle $\\la 40^\\circ$ relative to the spin axes of remnant SMBHs, implying that recoiling quasars are biased to be with high Doppler-shifted broad emission lines while recoiling radio galaxies are biased to large apparent spatial off-center displacements. We also calculate the distribution functions of line-of-sight velocity and apparent spatial off-center for spin-flip radio sources with different apparent jet reorientation angles. Our results show that the larger the apparent jet reorientation angle is, the larger the Doppler-shifting recoiling velocity and apparent spatial off-center displacement will be. We investigate the effects of recoiling velocity on the dust torus in spin-flip radio sources and suggest that recoiling of SMBHs would lead to "dust poor" AGNs. Finally, we collect a sample of 19 X-shaped radio objects and for each object give the probability of detecting the predicted signatures of recoiling SMBH.
F. K. Liu; Dong Wang; Xian Chen
Centrifugal compressor identification using LOLIMOT
Science Conference Proceedings (OSTI)
In this paper, the dynamics of a nonlinear centrifugal compressor which is used in compression of natural gas process, is identified using Locally Linear Model Tree (LOLIMOT) algorithm. Real data were collected from the performance maps of the system ... Keywords: LOLIMOT, centrifugal compressor, identification, neuro-fuzzy models, nonlinear, performance maps
Najmeh Daroogheh
Science Conference Proceedings (OSTI)
We report Chandra evidence for a 200 kpc scale shock in the cluster surrounding the powerful radio galaxy 3C 444. Our 20 ks observation allows us to identify a clear surface brightness drop around the outer edge of the radio galaxy, which is likely to correspond to a spheroidal shock propagating into the intracluster medium. We measure a temperature jump across this drop of a factor {approx}1.7, which corresponds to a Mach number of {approx}1.7. This is likely to be an underestimate due to the need to average over fairly large regions. We also detect clear cavities corresponding to the positions of the radio lobes, which is only the second such detection associated with an FRII radio galaxy. We estimate that the total energy transferred to the environment is >8.2 x 10{sup 60} erg, corresponding to a jet power >2.9 x 10{sup 45} erg s{sup -1}. Our results suggest that energy input from FRII radio galaxies is likely to exceed substantially estimates based on cluster cavity scaling relations.
Croston, J. H. [School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Hardcastle, M. J.; Mingo, B. [School of Physics, Astronomy and Mathematics, University of Hertfordshire, Hatfield, Hertfordshire, AL10 9AB (United Kingdom); Evans, D. A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Dicken, D. [Department of Physics and Astronomy, Rochester Institute of Technology, 84 Lomb Memorial Drive, Rochester, NY 14623 (United States); Morganti, R. [Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA, Dwingeloo (Netherlands); Tadhunter, C. N., E-mail: email@example.com [Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH (United Kingdom)
Exploring the infrared/radio correlation at high redshift
We have analysed the 24um properties of a radio-selected sample in the Subaru-XMM/Newton Deep Field in order to explore the behaviour of the FIR/radio relation at high redshifts. Statistically, the correlation is described by q24, the ratio between the observed flux densities at 24um and 1.4GHz, respectively. Using 24um data results in considerably more scatter in the correlation than previous work using data at 60-70um. Nevertheless, we do observe a steady correlation as a function of redshift, up to z~3.5, suggesting its validity back to primeval times. We find q24 = 0.30 +/- 0.56 for the observed and q24 = 0.71 +/- 0.47 for the k-corrected radio sample, based on sources with 300uJy 1mJy. The rest-frame U-B colours of the expected radio-excess population have redder distribution than those that follow the correlation. This is therefore a promising way to select obscured Type-2 AGN, with a radio loud nature, missed by deep X-ray observations. Spectroscopic follow-up of these sources is required to fully test this method.
Edo Ibar; Michele Cirasuolo; Rob Ivison; Philip Best; Ian Smail; Andy Biggs; Chris Simpson; Jim Dunlop; Omar Almaini; Ross McLure; Sebastien Foucaud; Steve Rawlings