Energy Technology Data Exchange (ETDEWEB)

The concept of a direct energy recovery system that applies a varying magnetic field is proposed for a negative-ion-based neutral beam injection system (NNB) to heat a plasma and/or drive a plasma current in a fusion reactor. The output beam energy and power of such an NNB will be {approximately}1 MeV and {approximately}1- MW/beam-line, respectively, and nearly the same amounts of positive- and negative-ion beams remain unneutralized in an NNB by using a gas-neutralizing cell. Therefore, the output of a beam direct convertor in an NNB is a bipolar direct current (dc) electric power with close to {plus_minus} 1 MV and several amperes if a conventional electrostatic or magnetostatic field is applied for ion beam separation. However, such high-voltage dc power is difficult to handle at the point of the regeneration of the ...

Energy Technology Data Exchange (ETDEWEB)

Abstracts of research projects are presented in the following areas: measurements and special facilities; cellular and subcellular studies; physiology; behavior; environmental effects; modeling, scaling and dosimetry; and high voltage direct current. (ACR)

Energy Technology Data Exchange (ETDEWEB)

A railgun has an armature driven between two rail-like conductors. In other words, it is a linear drive device system that drives airframes by using the Lorentz`s force. The system is expected as a next-generation high-speed transport means, or as a means to create such ultimate fields as ultra-high pressures, ultra-high temperatures, and ultra-ferromagnetic fields. This paper is a report on investigations on the relevant technological trends as surveyed by the investigation committee at the Institute of Electrical Engineers of Japan using research reports published inside and outside the country. The reported themes cover explanations from the construction to the pulse power supply that forms the core of the technology, problems in switching, recent status of research and development, and to application fields. Compatibility in the high-level electrical and mechanical performances demanded in the ...

Energy Technology Data Exchange (ETDEWEB)

A concept of direct energy recovery system applying an alternating or rotating magnetic field is proposed for a negative-ion-based neutral beam injection system (NNB) to heat a plasma and/or drive a plasma current in a fusion reactor. Nearly same amounts of residual positive and negative hydrogen-isotope ion beams with beam energy of {approx}1 MeV are produced in an NNB using a gas neutralizing cell. Consequently, a recovered energy is obtained directly in the form of ac electric power, if these positive- and negative-ion beams are alternated or rotated and introduced to two or more recovery electrodes in turn by an alternating or rotating magnetic field. This concept will greatly reduce a technological difficulty in regeneration of a recovered electric energy with such a very high voltage. (author).

Energy Technology Data Exchange (ETDEWEB)

A computer-aided design procedure has been developed for the series compensation of an extra high voltage line with a compensating network connected at one or the other end or both ends. Higher degree polynomial equations are derived in terms of compensating elements to compute the network parameters for optimum received power with constrained capacitor terminal voltage, safe line current, Ferranti voltage and transient stability. It is shown that series capacitors located at both ends provide the most effective means from the viewpoint of power transmission capability in either direction, transmission efficiency and series capacitor rating in comparison with a capacitor located at one or the other end.

Energy Technology Data Exchange (ETDEWEB)

Bremstrahlung Isochromat Spectroscopy (BIS). The XES spectra were collected using a Specs electron gun for the excitation and the XES 350 grating monochromator and channel plate system from Scienta as the photon detection. Spectra were collected in 'normal mode,' where the electron gun kinetic energy (KE) and the energy position of the center of the channel plate were both fixed and the energy distribution in the photon (hv) spectrum was derived from the intensities distributed across the channel plate detector in the energy dispersal direction. The polycrystalline Ce sample was oxidized by exposure to air at ambient pressures. After introduction to the ultra-high vacuum system, the oxidized sample was bombarded with Ar, to clean the topmost surface region and stabilize the surface and near surface regions. Although CeO{sub 2} would be the thermodynamically preferred composition in an ...

British Library Electronic Table of Contents (United Kingdom)

The problem of electrical parameters identification in complex systems, and in particular in electric railway traction systems, is considered. Parameters are determined by an indirect approach: only the terminal variables (voltages and currents and, impedance and admittance, which can be readily calculated) are measured and the per-unit-length electrical parameters are determined using a multiconductor transmission line model of the track section under test. It will be shown that some parameters cannot be measured directly, that they are not constant with frequency and that they may depend on other external conditions. An indirect method for parameters identification is proposed through an adaptive algorithm (AA), so that the calculated terminal variables match the measured ones. The AA is...

Energy Technology Data Exchange (ETDEWEB)

Distance protection, differential protection and directional comparison schemes are presently used for protecting transmission lines. Directional comparison relays are set to respond to faults in the protection zone without intentional time delay and are, therefore, used where high-speed fault clearing is needed. Artificial Neural Networks (ANNs) can handle most situations which cannot be defined sufficiently for finding a deterministic solution. The design and testing of an ANN for directional comparison protection of transmission lines are presented in this paper. Training patterns were generated using voltage and current samples for faults at various locations along a transmission line. The faults were simulated using an electromagnetic transient program and a sample three-phase power system. The performance of the proposed discriminator was checked using ...

Energy Technology Data Exchange (ETDEWEB)

The current-carrying capacity of oil-filled cables is increased by forced cooling, which is accomplished by three methods: direct, surface and internal, depending on the relative positions of the cable and the cooling agent. The surface and indirect methods are the simplest and are sufficiently effective methods of cooling and make it possible to improve the current-carrying capacity of cables already mastered by the USSR's industry. A calculation method is suggested for the proper determination of the permissible load on lines of these sorts. A procedure is presented whereby equations are derived which make it possible to calculate the temperature of elements of the system and by means of an iteration calculation a determination is made of the total heat flow from the cable with which the temperature of the conductor along the line does not exceed the permissible value. The permissible ...

Science.gov (United States)

A film of GaSb grown epitaxially on a Si substrate is a direct transition semiconductor useful for application as a light source in Si photonics and channel material in next-generation field effect transistors because its energy bandgap is close to the optical fibre communication wavelength and it possesses high carrier mobility. Here, we report a novel method for heteroepitaxial growth of high-quality GaSb/Si films, despite having a lattice mismatch as large as ? 12%, using elastically strain-relaxed GaSb nanodots with ultrahigh density as seed crystals for film growth. The nanodot seed crystals were grown epitaxially by restricted contact with the Si substrate through nanowindows in an ultrathin SiO(2) film on the Si substrate. A light-emitting diode containing GaSb/Si films with a thickness of ? 90 nm fabricated by this method operated at room temperature. The growth method was also used to fabricate AlGaSb films of high quality. Our method ...

International Nuclear Information System (INIS)

Manitoba Hydro's Ice Storm Management Program to reduce ice damage to overhead power lines in the voltage range of 8 kV to 115 kV is described. Overhead power lines are de-iced either by AC ice melting, which involves placing a three-phase short at a calculated point, or ice rolling, which is a process of mechanically stripping ice from conductors. Direct current heating and underground distribution systems are also accepted prevention measures. Advantages and disadvantages of each of these methods of de-icing are reviewed. Material for this paper has been extracted from a workshop manual prepared for the 1993 and 1998 Ice Storm Management workshops organized by Manitoba Hydro through the Canadian Electrical Association. 1 ref.

International Nuclear Information System (INIS)

In the last two decades, due to increased inspection demands, eddy current instrumentation has advanced from single-frequency, single-output instruments to multifrequency, computer-aided systems. This has significantly increased the scope of eddy current testing, but, unfortunately, it has also increased the cost and complexity of inspections. In addition, this approach has not always improved defect detectability or signal-to-noise. Most eddy current testing applications are still performed with impedance probes, which have well known limitations. However, recent research at AECL has led to improved eddy current inspections through the design and development of transmit-receive (T/R) probes. T/R eddy current probes, with laterally displaced transmit and receive coils, present a number of advantages over impedance probes. They have improved signal-to-noise ratio ...

International Nuclear Information System (INIS)

The experimental superconducting magnetic system of 0.5 MJ energy storage is described. The step variation of the winding inductance provides a control by the discharge current at the energy output on a high-ohmic load. The voltage on a load is 45 kV at the current 1100 A under the controllable discharge conditions. The energy transfer coefficient constitutes 0,76 under the maximum-to-minimal current ratio equal to 1.3. 7 refs., 3 figs., 2 tabs.

Energy Technology Data Exchange (ETDEWEB)

The performance of a 6 kW proton exchange membrane (PEM) electrolyzer was modeled using a semiempirical equation. Total cell voltage was represented as a sum of the Nernst voltage, activation overpotential and ohmic overpotential. A temperature and pressure dependent Nernst potential, derived from thermodynamic principles, was used to model the 20 cell PEM electrolyzer stack. The importance of including the temperature dependence of various model components is clearly demonstrated. The reversible potential without the pressure effect decreases with increasing temperature in a linear fashion. The exchange current densities at both the electrodes and the membrane conductivity were the coefficients of the semiempirical equation. An experimental system designed around a 6 kW PEM electrolyzer was used to obtain the current-voltage characteristics at different stack temperatures. A ...

International Nuclear Information System (INIS)

It is experimentally demonstrated that a relatively strong ion-rich sheath formed at a fixed negative bias of the grid can be changed to a rather weak ion sheath (sheath potential weakly retards electrons) only by increasing the discharge voltage in the system. At sufficiently high negative grid bias, an increase of discharge voltage enhances the ion collection current at the grid. An explanation is put forward in support of this experimental observation. A slight density enhancement with a fall in plasma electron temperature is also observed with the increasing negative grid bias. (authors)

International Nuclear Information System (INIS)

Nike is a recently completed multi-kilojoule krypton fluoride (KrF) laser that has been built to study the physics of direct drive inertial confinement fusion. This paper describes in detail both the pulsed power and optical performance of the largest amplifier in the Nike laser, the 60 cm amplifier. This is a double pass, double sided, electron beam-pumped system that amplifies the laser beam from an input of 50 J to an output of up to 5 kJ. It has an optical aperture of 60 cm x 60 cm and a gain length of 200 cm. The two electron beams are 60 cm high x 200 cm wide, have a voltage of 640 kV, a current of 540 kA, and a flat top power pulse duration of 250 ns. A 2 kG magnetic field is used to guide the beams and prevent self-pinching. Each electron beam is produced by its own Marx/pulse forming line system. The amplifier has been fully integrated into the Nike ...

Energy Technology Data Exchange (ETDEWEB)

A new type of impregnation jelly can be used instead of traditional oil may reduce the formation of cavities in marine high-voltage direct current cables. This provides a foundation for the development of cables with improved insulation and for higher power. This was a conclusion of the Norwegian ''EFFEKT''-project. Using the jelly reduces the size of the cavities substantially and no discharges seem to occur during formation, growth and collapse of cavities. It is also environmentally friendly, since there is no leakage of oil.

Energy Technology Data Exchange (ETDEWEB)

For over 50 years, the Bonneville Power Administration (BPA) has evolved to supply electric power to more than 170 customer utilities and direct service industries across 14,800 miles of high voltage transmission lines. BPA's Office of Engineering provides the planning, development, and engineering for the required expansion, upgrade, and replacement of the transmission system. The purpose of this 10-Year Plan is to present strategies to maintain a reliable energy delivery system within changing public, business, technological, and environmental climates. The issues and trends discussed in this document and our strategies for addressing them provide the background for the Office of Engineering programs and projects. With a budget in the hundreds of millions annually and increasing public concern, we welcome the opportunity to communicate with our customers. In addition to the factors, trends ...

International Nuclear Information System (INIS)

It is a traditional method to diagnose electron-cyclotron-resonance (ECR) plasma source, using a single probe to measure the current-voltage curve of the plasma, based on which and theoretic formula the plasma density can be computed. The article adopts a Langmuir probe having a role of emission electrons to measure two different current-voltage curves with and without emission. It is ease to get the plasma potential via the inflexion of the two curves and compute directly various physical quantities by the assistant computer, such as electron temperature, electron/ion density, plasma potential etc. The deviation is about percent 1.8 between the measurement results by traditional and the new method, but the latter has higher efficiency. (authors)

Energy Technology Data Exchange (ETDEWEB)

The paper begins with an introduction on the reasons that lead to the use of HVDC submarine cable links. The main aspects for the choice of direct current are presented as well as the advantages deriving from the utilization of submarine cables. The second part is dedicated to a discussion on the various type of insulation that could be used in power cables and their possible application to HVDC submarine cables. In the following there is a description of the main characteristics and technical details of some particular project that at present time (1995) are in progress. Two projects are briefly presented: Spain-Morocco, a 26 km long interconnection for the transmission, in a first phase, of 700 MW from Spain to Morocco at 400 kV a.c. by means of three cables, plus one spare, of the fluid filled type. The cables are designed for a future change to d.c. 450 kV, allowing a transmission of 500 MW each (i.e., 2 GW total). One of the peculiarities ...

International Nuclear Information System (INIS)

The nation's electric power system would be subject to induced surges in the event of a high altitude nuclear burst. The HEMP would be coupled to overhead power lines and cause severe overvoltage to components connected to the line. This paper discusses the design of pulsed power equipment needed to simulate this induced EMP. A facility is described which is capable of testing the vulnerability of components by applying appropriate voltage and current waveforms. The pulser can provide waveforms under a variety of test conditions to meet the requirements of different types of components. A 3-5 MV Marx pulser is described. It has the capability of generating a fast rising voltage followed by two distinct exponential decays. The testing of components, charged with their normal voltage is also described.

DEFF Research Database (Denmark)

We present a theoretical study of the resonant interaction between dynamical localized states (discrete breathers) and linear electromagnetic excitations (EE's) in Josephson junction ladders. By making use of direct numerical simulations we find that such an interaction manifests itself by resonant steps and various sharp switchings (voltage jumps) in the current-voltage characteristics. Moreover, the power of ac oscillations away from the breather center (the breather tail) displays singularities as the externally applied dc bias decreases. All these features may be mapped to the spectrum of EE's that has been derived analytically and numerically. Using an improved analysis of the breather tail, a spectroscopy of the EE's is developed, The nature of breather instability driven by localized EE's is established.

Energy Technology Data Exchange (ETDEWEB)

This patent describes an ignition system of an internal combustion engine which consists of: a permanent magnet supported by a rotary member of the engine adapted to rotate in synchronism with a rotary shaft of the engine; a generating coil for generating an electromotive force to produce an electric current as the permanent magnet acts on the generating coil during the rotation of the rotary member; an ignition capacitor charged by the electric current generated by the generating coil; a thyristor caused to turn on by a counter electromotive force generated by the generating coil to thereby cause the ignition capacitor to begin to discharge; and an ignition coil generating a high voltage as the ignition capacitor begins to discharge, to cause a spark discharge to take place in an ignition plug of the internal combustion engine.

International Nuclear Information System (INIS)

Measurements of the Kapitza conductance to liquid helium II across the (100) surface of single crystals of copper are presented. The temperature range of these measurements was 1.6-- 2.1 K. The sample surfaces were subjected to several different treatments. Some surfaces were cleaned by low-energy argon ion bombardment, annealed in an ultrahigh-vacuum system, and preserved under vacuum until purified liquid helium was admitted. Other surfaces were intentionally damaged by machining and/or exposure to the atmosphere. The conductance after these latter treatments was found to be about a factor of three higher than that of the more ideally cleaned and annealed surfaces, and a significant difference in the temperature dependence of the conductance was also observed. Conductances were reproducible for similarly treated surfaces and correlated with surface damage determined by x-ray diffraction. The relationship of these results to the numerous ...

Energy Technology Data Exchange (ETDEWEB)

The authors address the question of the limitations on voltage and current transfer to loads in magnetic storage systems utilizing microsecond conduction time plasma opening switches. They propose that the limitation of performance results from neutral atoms that are not entrained into the ionized material that is driven by the magnetic field of the rising generator current. Evidence in support of this proposition is gathered from experiments performed on the Ace-4 and Hawk generators. They set forth a theory to describe the effect of neutrals on the electrical performance of plasma opening switches. The neutral gas is assumed to be present in the region between the moving plasma mass and the generator, primarily in the region in which the plasma is injected initially. The essential elements of the theory are a weak photoionization source to seed the gas with a low concentration of electrons, and joule ...

Energy Technology Data Exchange (ETDEWEB)

An integrated voltage regulator and power system stabilizer based on one step ahead prediction is presented. The fixed parameter predictive control scheme is shown capable of providing consistently good voltage response and contribution to system damping over a wide range of operating conditions and system configuration. This is in contrast to the case with conventional automatic voltage regulator and power system stabilizer where performance varies widely with the operating situation and can even cause system instability. (author)

International Nuclear Information System (INIS)

The authors report on observations of plasma wave turbulence generated during electron beam injections, spacecraft potential variations, and neutral gas emissions of the CHARGE 2 sounding rocket experiment. The payload was flown in a mother/daughter configuration, with the two sub-payloads electrically connected by an insulated, conducting tether. While tethered, the two platforms were separated, drifting apart in a direction perpendicular to both the magnetic field and to the spacecraft velocity, reaching a maximum distance of 426 m at the end of the flight. The mother carried a high-voltage (HV) system (0-460 V), biasing the mother negative relative to the daughter. The operation of the HV bias system simulated the motional emf induced in larger orbiting space structures like the Tethered Satellite System 1 (TSS 1) space shuttle mission scheduled for the spring of 1992. In ...

Energy Technology Data Exchange (ETDEWEB)

In the 14 MeV Neutron Laboratory, we have continued the development of a facility that is now the only one of its kind in operation in the United States. We have refined the klystron bunching system described in last year's report to the point that 1.2 nanosecond pulses have been directly measured. We have tested the pulse shape discrimination capability of our primary NE 213 neutron detector. We have converted the RF sweeper section of the beamline to a frequency of 1 MHz to replace the function of the high voltage pulser described in last year's report which proved to be difficult to maintain and unreliable in its operation. We have also overcome several other significant experimental difficulties, including a major problem with a vacuum leak in the main accelerator column. We have completed additional testing to prove the remainder of the generation and measurement systems, but ...

Energy Technology Data Exchange (ETDEWEB)

Radio interference and TV interference are being a problem in urban and rural areas. This interference is generated by high voltage transmission lines as well as distribution lines. The radio noise can be produced by polluted or damaged insulators, and by metal parts of the distribution lines. The corona effect on the surface of the dielectric material produces high frequency electromagnetic fields during the ionization and during the recombination period. Fields of different intensity are produced by positive voltage and negative voltage. The insulator flashover (leaking current) also produces electromagnetic fields. A new technique to measure these fields was developed. This technique measures the radiated fields on time domain and on frequency domain. This permits us to characterize the radiated field and thus identify the type of the source. Several measurements were done varying the type of the RF ...

Energy Technology Data Exchange (ETDEWEB)

The paper-insulated low-pressure oil-filled cable invented in 1917 has been used throughout the world as the major cable system for voltages from 33kV to 525kV and experimentally to 1100kV. The proven reliability of the design is amply demonstrated by the cables installed in the early 1930s still currently in service. The inherent design of an oil-filled cable requires that the low viscosity oil is retained within a lead or aluminium sheath. Changes in oil volume due to changes in ambient temperature and load are accommodated by oil reservoirs which maintain the cable oil pressure within design limits. A microprocessor monitoring system that allows early detection and quick location of oil leaks from high voltage oil-filled cables is described.

KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

Heat exchangers for high and ultrahigh temperatures are a need and a precondition to realise high efficient fossil fired power plants based on the so-called Externally Fired Combined Cycle (EFCC) or the Indirect Fired Gas Turbines (IFGT). The main target of both processes is to increase the thermal efficiency of existing power plants by approximately 25% resulting in the same decrease in fuel consumption and, therefore, in the same reduction of CO{sub 2} formation. The main activities of the MPA University of Stuttgart in this project is focused on the characterisation and qualification of the structural material of the ultrahigh temperature heat exchanger (UHTHE) necessary in the above mentioned processes. The influence of the temperature and load on the material behaviour have been analysed by means of tensile tests and creep tests. The effectiveness of different coating systems and the interaction between coating ...

Energy Technology Data Exchange (ETDEWEB)

This paper presents some results of lightning induced over voltages for a typical high voltage transmission line configuration. The authors developed an elaborated electromagnetic coupling between the lightning channel and characteristics and the resulting induced overvoltage. The lightning current parameters, for local data, in order to determine the occurrence severity for high voltage transmission lines. (author)

Energy Technology Data Exchange (ETDEWEB)

This work describes the development of a synchronous key based on micro controller to the switching of three-phase power transformers, which makes possible the achievement of tests to register the inrush current, and the previous establishment of the instantaneous values of the voltage firstly applied to different phases of the energy process. This key is a value tool to the development electric power system projects and to the teaching and researching activities at the laboratory related to transitory phenomena and electric system protection.

UK PubMed Central (United Kingdom)

In the American educational system, school transitions are frequent and predictable, but they can disrupt student functioning across developmental domains. How students experience school transitions...Full Text Available

Science.gov (United States)

Electric utilities have been surprised by recent opposition to the construction of very-high-voltage transmission lines, which met with little resistance in the past. Concerns over health and safety factors are associated with the increase in the number of such lines, although their presence has always been an inconvenience and a hazard for those living and working in the immediate vicinity. The new lines present additional hazards due to the continuous flow of small electric currents and the charges that build up in the area of the towers and lines. The lines are also a threat to persons wearing cardiac pacemakers. There is experimental evidence from the Soviet Union and the U.S. that electric and magnetic fields at the frequencies of such power lines can have serious biological effects on growth rates and the functioning of the central nervous system. Full disclosure that possible risks are involved and the opportunity to ...

Energy Technology Data Exchange (ETDEWEB)

The study of audible noise from high voltage transmission lines and a high voltage transformer station was conducted in three parts. Part 1 consisted of long-term measurement and statistical analysis by computer reduction of audible noise as a result of corona discharge from high voltage transmission lines and the associated weather conditions which contribute to this noise. Recommendations are given concerning further computer programming in order to improve the statistical reliability of corona noise presence and reduce the degree of background noise contamination of the present results. Part 2 consisted of categorizing and cataloguing of corona noise spectra from long-term measurements on 550, 735 and 765 kV transmission lines and to provide a library of such sounds on magnetic tape to be used in the ongoing study of corona noise. Twenty-five different corona sound spectra have been identified and documented in a tape ...

Energy Technology Data Exchange (ETDEWEB)

A general calculation method for the analysis of transmission capability of a long-distance single-core ac submarine cable system is presented. The method is based on modal transformation of voltages and currents in multiconductor cable systems. Using this method, numerical calculations on 500 kV submarine cable systems have been performed with particular reference to the effect of the distance between bonds connecting metallic sheath, outer conductor and armor on the transmission capacity of the system. It was clarified that the transmission capacity of the system increased with decreasing bond intervals. Examination of the current distributions between various conductors along the length showed that this increase of transmission capacity was mainly due to the dispersion of the charging current into ...

Energy Technology Data Exchange (ETDEWEB)

In this thesis a study is made of the of voltage characteristics and reactive power control in the transmission network of the Electric Power Systems (EPS) with static compensators of VARs (SCVs). The necessity of voltage and reactive power control and the application of SCVs as a solution means for three representative operation stages of the EPS, considering balanced operation conditions and fundamental frequency is analyzed: Operation in the presence of incremental voltage changes, quasi-stationary operation or steady state and behavior at the occurrence of big disturbances. The application of SCVs to systems of integral transmission is in general a closed loop control system, reason why the analysis of the interaction of the system EPS-SCV is considered as an essential part of the voltage and reactive power control ...

Science.gov (United States)

This paper discusses a new control strategy for photovoltaic power generation systems with consideration of dynamic characteristics of the photovoltaic cells. The controller estimates internal currents of an equivalent circuit for the cells. This estimated, or the virtual current and the actual voltage of the cells are fed to a conventional Maximum-Power-Point-Tracking (MPPT) controller. Consequently, this MPPT controller still tracks the optimum point even though it is so designed that the seeking speed of the operating point is extremely high. This system may suit for applications, which are installed in rapidly changeable insolation and temperature-conditions e.g. automobiles, trains, and airplanes. The proposed method is verified by experiment with a combination of this estimating function and the modified Boehringer's MPPT algorithm.

International Nuclear Information System (INIS)

Macroparticle acceleration driven by low current, high voltage cathode spots has been investigated for potential applications ranging from micrometeoroid simulation to nanoparticle deposition/implantation. Acceleration by this process was observed to occur when nanometer and micrometer-sized particles were exposed to a high voltage pulse in the presence of a plasma discharge. The applied negative voltage pulse initiates the formation of multiple, high voltage, low current cathode spots which provide the mechanism of actual acceleration of the charged dust particles. Dust streams generated by this process were detected using laser scattering techniques. Cathode spot behavior was also documented. The particle impact craters observed at the surface of downstream witness badges were documented using scanning electron microscopy and light microscopy. The observed ...

Energy Technology Data Exchange (ETDEWEB)

The Segmented Rail Phased Induction Motor (SERAPHIM) is a compact, pulsed linear induction motor (LIM) offering a unique capability for very high speed train propulsion. It uses technology developed for the Sandia coilgun, an electromagnetic launcher designed to accelerate projectiles to several kilometers per second. Both aluminum cylinders and plates were accelerated to a kilometer per second (Mach 3) by passing through a sequence of coils which were energized at the appropriate time. Although this technology was developed for ultra-high velocity, it can be readily adapted to train propulsion for which, at sea level, the power required to overcome air resistance limits the operational speed to a more modest 300 mph. Here, the geometry is reversed. The coils are on the vehicle and the ``projectiles`` are fixed along the roadbed. SERAPHIM operates not by embedding flux in a conductor, but by excluding it. In this propulsion scheme, pairs of closely spaced coils on ...

Environmental Research Database

ObjectivesObjectives Not AvailableDescriptionThis proposal seeks to extend what is currently the most comprehensive offshore environmental data collection programme at a platform on the UKGS involving continuous collection of wave height and direction, wind speed and direction, current and wave particle kinematics. Data has been collected with this system since 1994 and the proposal is to extend this until 1999 thus providing an extensive set of storm data collected at 5Hz which will allow examination of the joint behaviour of wave, wind [continued...

Energy Technology Data Exchange (ETDEWEB)

A physical explanation is given for the positive differential voltage-current characteristic seen at low current in weakly ionized, low-pressure positive column discharges in argon/mercury gas mixtures. {copyright} {ital 1996 The American Physical Society.}

Energy Technology Data Exchange (ETDEWEB)

Transmission line faults must be located accurately to allow maintenance crews to arrive at the scene and repair the faulted section as soon as possible. Rugged terrain and geographical layout cause some sections of power transmission lines to be difficult to reach. In the past, a variety of fault location algorithms were introduced as either an add-on feature in protective relays or stand-alone implementation in fault locators. In both cases, the measurements of current and voltages were taken at one terminal of a transmission line only. Under such conditions, it may become difficult to determine the fault location accurately, since data from other transmission line ends are required for more precise computations. In the absence of data from the other end, existing algorithms have accuracy problems under several circumstances, such as varying switching and loading conditions, fault infeed from the other end, and random value of fault ...

Science.gov (United States)

The possibility of using lead or lead-bismuth mixed oxides as positive materials in organic electrolyte lithium cells with a working voltage similar to those of conventional systems (1.5 V) has been considered. Performances and main characteristics of this new class of lithium batteries are described.

International Nuclear Information System (INIS)

We have fabricated MgB_2 dc SQUIDs (superconducting quantum interference devices) containing inter-grain nanobridges as Josephson elements by a focused ion beam (FIB) etching method and measured their transport properties. The entire structure including the SQUID loop was patterned only using a FIB. The beam energy was 30 kV and the current was 0.9 nA for larger structures and 34 and 1.5 pA for the nanobridge pattern. Each bridge with a nominal width of 100 nm crossed a single grain boundary in the normal direction. The SQUID loop had a 3.1 #mu#m x 3.1 #mu#m hole with a 2 #mu#m average linewidth, corresponding to an inductance of 5.1 pH. The nanobridges had a two-step transition with an increase in the resistivity of more than a decade and a substantial decrease in the critical current density. Current-voltage characteristics showed a resistively shunted junction behavior at all temperatures below T_c, ...

Energy Technology Data Exchange (ETDEWEB)

Pd was deposited onto Si (111) 7x7 surface at approximately 700 K inside an ultrahigh vacuum transmission electron microscope. Plan-viewed transmission electron microscopy (TEM) observation indicated that the islands have two kinds of shapes, round and rectangular (one-dimensional) ones. In a diffraction pattern for the rectangular islands, extra spots along the <110> direction of the Si surface, spacing of which is 1/8 times as long as that of Si (220) spots, were seen. A high resolution TEM image showed the corresponding superstructure in the rectangular islands. In situ observation of the growing process of the rectangular islands showed repeat of introduction and relief of strains during the growth, suggesting that such superstructure would be constructed by stacking compositionally different phases or introducing defects so that the periodically maximized strain is relieved.

Energy Technology Data Exchange (ETDEWEB)

This third report covers the period October 1 to November 30, 1991. During this period the authors: (1) fabricated a test fixture for studying hybrid armature brush behavior, (2) reactivated a 140kJ, 1MA capacitor bank, (3) reactivated 25 channels digital data acquisition and reduction system and (4) concluded the use of a DNA funded railgun would serve as the most expedient means to acquire a railgun test bed. Fabrication of a plasma brush test fixture for studying the formation, evolution and stability of plasma brushes was completed. The fixture will serve to study plasma brush parameters, such as brush length and voltage drop, as a function of initial solid foil mass, gap size and current concentration. A 4OkV, 168{mu}f, 140kJ capacitor bank capable of providing more than 1MA of current was reactivated. (The LLNL bank had been developed for opening switch research which was successfully completed.) ...

Energy Technology Data Exchange (ETDEWEB)

An IEC-TDG waveform analysis program that can accurately calculate the waveform parameters in waveforms containing much noise as well as waveforms based on the IEC 1083-2 standard was developed in the impulse voltage and current test field. In the conventional curve fitting method, it is difficult to solve the non-linear equation directly when obtaining waveform parameters from the assigned discrete data. An approximate solution method is low in precision. Therefore, the residual between the standardized data and approximate function was calculated for high-speed Fourier transformation. Unrelated components were eliminated from the calculated frequency spectrum to synthesize waveforms. An L-M method is used for analysis. The solution is first tracked by a maximum diving method. If the convergence is judged to have been largely promoted, the method is switched into a Newton method to continue the calculation. The non-linear ...

Energy Technology Data Exchange (ETDEWEB)

Much attention is being paid to electric vehicles from environmental standpoints. One disadvantage of the electric vehicle is that its operative range is short. A means to overcome this difficulty is to use a hybrid battery which consist of a energy battery and a power battery. A method to make it possible to calculate the discharge characteristics of the battery hybrid system taking into account the charging behavior from the energy battery to the power battery is presented. In the proposed method, first the output voltage and the output current of an equivalent battery, which is required for realizing the given operating pattern are calculated. Next, the conduction ratio of the main chopper and the equivalent discharge of electric charge of each battery are calculated. These calculated data are used to calculate the operating range.

KoreaScience (Korea)

Full Text Available

International Nuclear Information System (INIS)

Current effort of the TAMA project is focused on establishment of the interferometer operation with a new vibration isolation system, called 'Seismic Attenuation System' (SAS). The SAS employs a multiple stage structure to realize soft spring for all of directions, as well as utilizes active control systems to stabilize mechanical resonances in the low frequency region below 1 Hz. The SASs were installed for four test masses, resulting in improvement of cavity length fluctuation below 150 Hz. We describe the structure of the SAS and its local active control system, and the status of the interferometer.

International Nuclear Information System (INIS)

We investigate the efficacy of mitigating radiation-based single event effects (SEE) within circuits incorporating SiGe heterojunction bipolar transistors (HBTs) built with an N-Ring, a transistor-level layout-based radiation hardened by design (RHBD) technique. Previous work of single-device ion-beam induced charge collection (IBICC) studies has demonstrated significant reductions in peak collector charge collection and sensitive area for charge collection; however, few circuit studies using this technique have been performed. Transient studies performed with Sandia National Laboratory's (SNL) 36 MeV 16O microbeam on voltage references built with N-Ring SiGe HBTs have shown mixed results, with reductions in the number of large voltage disruptions in addition to new sensitive areas of low-level output voltage disturbances. Similar discrepancies between device-level IBICC results and circuit measurements are found for the ...

International Nuclear Information System (INIS)

Full text: As you know, thin films which generate anomalous big photovoltage (APhV) , as film photo resistive structures made of the combinations of A_2B_6 respond to X-ray and #gamma#- radiations. In this work the influence of X-ray and #gamma#-radiations on the quantity of APhV in the system APhV-film-photoresistor was investigated. Earlier polycrystal films with anomalous photo voltage properties were received only on the clean and flat surface with high isolation property (R>10"1"4 #OMEGA#). We worked out the technology of receiving APhV films CdTe on the surface of the photosensitive film CdS. The main condition under which this effect may be observed is that the lining must be slant concerning to the direction of the motion of evaporated substance's molecular bunch during the growing of the film, i.e. received film must have a dendritic structure. That is why photosensitive film CdS was received with thermo vacuum ...

Energy Technology Data Exchange (ETDEWEB)

The author explains current developments in high voltage cable technology and subsequently describes problems inherent in its application, from the users viewpoint, in municipal electricity supply. The planning of a high voltage cable network and the selection of a specific type of cable are not only dependent on the typical properties of various cables but to a major degree also on the feasible laying technique, the power transmitted, the costs, the stellation treatment of the high voltage network, the acceptance requirement, the inductive influence from telecommunication cable, thermal influences from the environment, eventual safeguards from mechanical and chemical damage to the network, frequency of failure and surveillance and breakdown location. In conclusion, the author portrays potential developments in the fields of high and maximum voltage cable from the perspectives of ...

Energy Technology Data Exchange (ETDEWEB)

The effects of gate and drain bias stresses on thin film transistors fabricated in polysilicon films crystallized using the advanced sequential lateral solidification excimer laser annealing (SLS ELA) process, which yields very elongated polysilicon grains and allows the fabrication of TFTs without grain boundary barriers to current flow, are investigated as a function of the active layer thickness and of the TFT orientation relative to the grains. The application of hot carrier stress, with a condition of V{sub GS} = V{sub DS}/2, was determined to induce threshold voltage, subthreshold swing and transconductance degradation for TFTs in thicker polysilicon films and the associated stress-induced increase in the active layer trap density was evaluated. However, this device degradation was drastically reduced for TFTs fabricated in ultra-thin films. Furthermore, the application of the same stress condition to TFTs oriented vertically to the ...

Energy Technology Data Exchange (ETDEWEB)

The microelectronic cable diagnosis is a substantial tool to determine destruction free the residual strength and the lifetime of laid PE/XLPE medium voltage cables. Fundamentals of the ageing diagnosis and a cost reduced inspection concept are the `Isothermal-Relaxation-Current` Analysis and the Neuro-Fuzzy evaluation software. These new tools are able to determine the ageing status of the investigated cable without any references. The authors also show that the test breakdown during the assessment of the ageing status of criterial systems can be reduced by this approach. The cable diagnosis equipment KDA is also useful for the steering of investment as well as for preventive maintenance. (orig.) [Deutsch] Die zerstoerungsfreie dielektrische Kabeldiagnostik kann heute einen wesentlichen Beitrag zur Bestimmung der Restfestigkeit und der Restlebensdauer eines PE/VPE-isolierten Mittelspannungskabels leisten. Basis der ...

International Nuclear Information System (INIS)

The existing Tokamak Fusion Test Reactor Neutral Beam system is proposed to be modified for long pulse operation on the Tokamak Physics Experiment (TPX). Day one of TPX will call for one TFTR beamline modified for 1000 second pulse lengths oriented co-directional to the plasma current. The system design will be capable of accommodating an additional co-directional and a single counter directional beamline. For the TPX conceptual design, every attempt was made to use existing Neutral Beam hardware, plant facilities, auxiliary systems, service infrastructure, and control systems. This paper describes the moderate modifications required to the power systems, the ion sources, and the beam impinged surfaces of the ion dumps, the calorimeters, the various beam scrapers, and the neutralizers. Also described ...

Energy Technology Data Exchange (ETDEWEB)

This report describes a study to evaluate methods for locating leaks of dielectric fluid from buried high-voltage cable systems. Two primary types of leak location systems were investigated: (1) systems that will rapidly isolate the leak within a manhole section, typically 1000-m long on a feeder that might be 30-km long; and (2) systems that will then pinpoint the location of the leak. Rapid leak isolation was accomplished by developing an enhanced conductivity oil probe which allows the injection of a small quantity of conductive oil and which indicates the path of the oil as it drifts downstream in the direction of the leak. Two methods for pinpointing the leak were proven. The more successful method was the use of trained leak location dogs which were found to have far better sensitivity than instruments and which could detect cable oil alone without the ...

International Nuclear Information System (INIS)

Mini-LIA is a miniature of a linear induction accelerator developed by China Academy of Engineering Physics and Tsinghua University in 2007. It has been constructed with a thermionic cathode in an electron injector and a metglas core in the induction accelerator cavities. A double-pulsed electron beam was produced for the first time in China on the Mini-LIA with a thermionic cathode in the electron gun and a metglas core in the induction accelerator cavities. A double-pulsed beam current of more than 1.1A was obtained on condition of 80 kV double-pulsed high voltage produced by pulsed power system supplying to the injector and accelerating modules. Some primary experiments for measuring the parameters of Mini-LIA has been performed, and some beam characterizations of Mini-LIA are presented. Further improvement is underway. (authors)

International Nuclear Information System (INIS)

We present and characterize a very efficient optical device that employs the plasma mirror technique to increase the contrast of high-power laser systems. Contrast improvements higher than 104 with 50% transmission are shown to be routinely achieved on a typical 10 TW laser system when the pulse is reflected on two consecutive plasma mirrors. Used at the end of the laser system, this double plasma mirror preserves the spatial profile of the initial beam, is unaffected by shot-to-shot fluctuations, and is suitable for most high peak power laser systems. We use the generation of high-order harmonics as an effective test for the contrast improvement produced by the double plasma mirrors. (authors)

Energy Technology Data Exchange (ETDEWEB)

In this work we present the electrical characterization of non self-aligned p-channel thin film transistors fabricated by using laser doping technique for source/drain contact formation and gate oxide deposited at room temperature by Electron Cyclotron Resonance Plasma Enhanced Chemical Vapour Deposition. These techniques are suitable for a very low temperature process for TFT fabrication. The output characteristics show a current increase at high drain voltage ('kink' effect) rather moderate, if compared to self aligned polysilicon TFTs, probably due to the gradual doping profile induced by laser doping process. After bias stress at low gate voltage and high drain voltage condition a strong reduction of kink current has been observed in the output characteristics at high drain voltage, whereas minor changes has been observed in the transfer ...

Energy Technology Data Exchange (ETDEWEB)

This report describes the physical characteristics of a ceramic-lined, joule-heated glass melter that is directly connected to the discharge of a spray calciner and is currently being used to study the vitrification of simulated nuclear-waste slurries. Melter performance characteristics and subsequent design improvements are described. The melter contains 0.24 m/sup 3/ of glass with a glass surface area of 0.76 m/sup 2/, and is heated by the flow of an alternating current (ranging from 600 to 1200 amps) between two Inconel-690 slab-type electrodes immersed in the glass at either end of the melter tank. The melter was maintained at operating temperature (900 to 1260/sup 0/C) for 15 months, and produced 62,000 kg of glass. The maximum sustained operating period was 122 h, during which glass was produced at the rate of 70 kg/h.

Energy Technology Data Exchange (ETDEWEB)

Railways and electrical traction systems require high power rates to achieve their operating performances. Systems of power supply based on super-capacitors should offer high power density along with good energy efficiency and expected operating safety. We investigate general behaviours of super-capacitors with two powerful methods of analysis. The first is constant charge/discharge current at high level value (500 A), the second is impedance spectroscopy which leads to the acquisition of a set of parameters that are considered sufficient to describe general properties of super-capacitor, in particular the state of health and the available energy in any operating conditions. An electrical circuit model is defined for super-capacitors based on activated carbon and organic electrolyte. It takes into account the dependence of super-capacitor to voltage and current. The mixture of data ...

British Library Electronic Table of Contents (United Kingdom)

The characteristics of diffuse glow discharges in pure argon and the Ar + 1%N2 mixture at pressures of 2?80 Torr were studied experimentally and numerically. The discharge operated in a molybdenumglass tube with an inner diameter of 2.8 cm and interelectrode distance of 75 cm. The current-voltage characteristic of the discharge and the populations of the N2(B3? g ) and N2(C3? u ) states were measured. It is shown that, at relatively low pressures (P 15 Torr), the current-voltage characteristic of a discharge in the mixture lies lower than that in pure argon. As the pressure increases, the effect of the reduction in the discha...

British Library Electronic Table of Contents (United Kingdom)

A solar water splitting cell composed of WO3, Polymer Electrolyte Membrane (PEM) and Pt was constructed for producing hydrogen from deionized water in sunlight. Spectral responsivity measurements under various temperatures and bias voltages were conducted for the cell using the Incident Photon to Current Efficiency (IPCE) method. For comparison, a known WO3 Photo Electro Chemical (PEC) cell containing H3PO4 electrolyte, WO3/H3PO4/Pt, was tested using the same test method. The WO3/PEM-H2O/Pt cell showed better Quantum Efficiency (QE) performance compared to that obtained from the cell with the chemical electrolyte. For the first time, spectral responsivity of photo water splitting process without bias power was unveiled in the new WO3 cell, demonstrating the self-sustained photo electrolysi...

Energy Technology Data Exchange (ETDEWEB)

A low voltage FEL operating at 130 kV which can be run cw with a continuous electron beam current level up to 12 mA has been constructed for the X-Band microwave range (8-12 GHz). In this poster, we will report on the dependence on time, after the electron beam is switched on, of the growth and competition of those longitudinal modes in the cavity having nett gain.

Energy Technology Data Exchange (ETDEWEB)

We present two new techniques that enhance conventional focused ion beam (FIB) system capabilities for integrated circuit (IC) analysis: in situ electrical biasing and voltage contrast imaging. We have used in situ electrical biasing to enable a number of advanced failure analysis applications including (1) real time evaluation of device electrical behavior during milling and deposition, (2) verification of IC functional modifications without removal from the FIB system, and (3) ultraprecision control for cross sectioning of deep submicron structures, such as programmed amorphous silicon antifuses. We have also developed FIB system voltage contrast imaging that can be used for a variety of failure analysis applications. The use of passive voltage contrast imaging for defect localization and for navigation on planarized devices will be illustrated. In addition, ...

Science.gov (United States)

... Multivibrators were used in the first model, which is called the "MV Model." Mwe second model, "1ST Model," has a saw-toothed voltage. ...

Energy Technology Data Exchange (ETDEWEB)

The paper presents an alternative approach for the studies of high voltage transmission lines based on artificial intelligence and more specifically artificial neural networks (ANNs). In contrast to the existing conventional-analytical techniques and simulations which are using in the calculations empirical and/or approximating equations, this approach is based only on actual field data and actual measurements. The proposed approach is applied on high voltage transmission lines in order to calculate the lightning outages, on grounding systems in order to assess the grounding resistance and on high voltage transmission lines' polluted insulators in order to estimate the critical flashover voltage. The obtained results are very close to the actual ones for all three case studies, something which clearly implies that the ANN approach is well working and has an acceptable ...

CERN Document Server

The goal of this work is to minimize the energy dissipation of embedded controllers without jeopardizing the quality of control (QoC). Taking advantage of the dynamic voltage scaling (DVS) technology, this paper develops a performance-aware power management scheme for embedded controllers with processors that allow multiple voltage levels. The periods of control tasks are adapted online with respect to the current QoC, thus facilitating additional energy reduction over standard DVS. To avoid the waste of CPU resources as a result of the discrete voltage levels, a resource reclaiming mechanism is employed to maximize the CPU utilization and also to improve the QoC. Simulations are conducted to evaluate the performance of the proposed scheme. Compared with the optimal standard DVS scheme, the proposed scheme is shown to be able to save remarkably more energy while maintaining comparable QoC.

Energy Technology Data Exchange (ETDEWEB)

Recently, the public has become aware of keywords like ''Quantum computer'' or ''Quantum cryptography''. Regarding their potential application in solid state based quantum information processing and their overall benefit in fundamental research quantum dots have gained more and more public interest. In this context, quantum dots are often referred to as ''artificial atoms'', a term subsuming their physical properties quite nicely and emphasizing the huge potential for further investigations. The basic mechanism to be considered is the theoretical model of a two-level system. A quantum dot itself represents this kind of system quite nicely, provided that only the presence or absence of a single exciton in the ground state of that structure is regarded. This concept can also be expanded to the presence of two excitons (bi-exciton). ...

Energy Technology Data Exchange (ETDEWEB)

Development of electronic devices with better performance and smaller size requires the passive components to be embedded within a printed wire board (PWB). The 'film-on-foil' approach is the most viable method for embedding these components within a PWB. We have deposited high-permittivity ferroelectric lead lanthanum zirconate titanate (Pb{sub 0.92}La{sub 0.08}Zr{sub 0.52}Ti{sub 0.48}O{sub x}, PLZT 8/52/48) films on base metal foils by chemical solution deposition. These prefabricated capacitor sheets can be embedded into PWBs for power electronic applications. To eliminate the parasitic effect caused by the formation of a low-permittivity interfacial oxide, a conductive buffer layer of lanthanum nickel oxide (LNO) was applied by chemical solution deposition on nickel foil before the deposition of PLZT. With a {approx} 0.7-{micro}m-thick ferroelectric PLZT film grown on LNO-buffered nickel foil, we measured capacitance densities of 1.5 {micro}F/cm{sup 2}, breakdown ...

Energy Technology Data Exchange (ETDEWEB)

The current--density profile of a focused ion beam (FIB) has a central peak accompanied by broader ``wings`` that, while unimportant in lithographic applications, can lead to unwanted effects during an implantation operation. The origin of the wings, and hence the best way to minimize them, is not clear and needs further study. We have measured the line profiles of several of the ions available in our FIB machine as a function of a number of variables, under ultrahigh vacuum (UHV) conditions. No effects are observed from changes in emission current or deliberate defocusing of the objective lens. There are some changes with beam aperture and/or current, but the biggest differences seem to be associated with a change of source type and hence, possibly, with a change in the source/extractor configuration or in the alloy and the emission process. The wing amplitudes are appreciably lower than many ...

Energy Technology Data Exchange (ETDEWEB)

This paper presents a new application in dynamic voltage control based on an older method of voltage regulation. The resulting method is suitable for adoption inn multi-unit pumped storage plants. Inherent operation characteristics of pumped storage plants in the pumping mode can created visible load rejection overvoltages on the transmission and the nearby distribution networks and cause customer complaints. This paper proposes a method in which the on-line units' excitation system impedance compensators are utilized to reduce the magnitude of these overvoltages. This paper presents the theoretical background, computer simulation results, and the field test results at the Pacific Gas and Electric Company's Helms Pumped Storage Plant. This paper should be of interest in the areas of power system planning as well as power system operation.

Energy Technology Data Exchange (ETDEWEB)

The numerous challenges facing the North American electric utility industry were discussed. In addition to competition, electric utilities are faced with low demand growth, public pressure to avoid adding transmission and distribution capacity, and strict environmental requirements. In view of these developments, large central generation additions that have been industry norm until recently, do not always make economic sense in the current environment. Instead, smaller, distributed additions to generating capacity is becoming the new norm. Small-scale on-site generating capacity has the added advantage of reducing the need for expensive high-voltage transmission lines. The Ballard generation system described here is a modular, efficient fuel cell-based solution to implementing distributed power concepts. The system is natural gas fueled, with low noise, vibration and emissions. Apart from its other ...

British Library Electronic Table of Contents (United Kingdom)

We investigate quantum mechanical electron transport along the long axis of the DNA molecule using an effective tight-binding model. The overall contour plot of transmission, the current-voltage characteristics, and the differential conductance are examined for the variation of backbone onsite energy, the energy-dependent hopping strength, and the contact coupling between the leads and the DNA molecule. It is shown that as backbone asymmetry increases, the merging and collapse of the two mini-bands take place and an extra resonance peak in the transmission appears. In addition, we present the modulation of voltage threshold in the current-voltage curves and a double-peak structure in the differential conductance due to the disappearance of the merged mini-band. Finally, in the Coulomb bloc...

Energy Technology Data Exchange (ETDEWEB)

The purpose of this paper is to evaluate the role of the strain-relaxation processes on the leakage current of embedded SiGe S/D junctions. Current-voltage (I-V) and capacitance-voltage (C-V) characteristics were measured to further investigate the relaxation degree of embedded SiGe S/D junctions in the regime where partial relaxation by misfits dislocations is assumed, yielding a reduction of the leakage current density. Further, the impact of the ion implantation-related defects on the electrical performance is discussed. The analysis is complemented with structural characterization based on High Resolution Transmission Electron Microscopy (HRTEM) and Nomarski microscopy. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Energy Technology Data Exchange (ETDEWEB)

A Vacuum Circuit Breaker demonstrated its ability to interrupt short circuits with faster than normal rates of rise of Transient Recovery Voltage (TRV) at levels greater than those produced by most transformer secondary faults. Two recent exploratory test programs evaluated the interrupting ability of a 15kV Vacuum Circuit Breaker containing interrupters of the rotating arc type with contacts made from a Chromium-Copper powder metal mixture. The interrupting conditions covered a wide range of currents from 10% to 130% of the 28kA rated short circuit current of the tested circuit breaker and a wide range of TRV rates of rise, including the relatively slow rate of rise, normally used in testing and found in most indoor circuit breaker applications; two faster rates of rise equaling and exceeding those found in a known power plant transformer secondary protection application; and the fastest rates of rise possible in the ...

Energy Technology Data Exchange (ETDEWEB)

In the Joule II project JOU2-CT 94-0428 `Development and Testing of Stand-Alone small-size Solar Photovoltaic-Hydrogen power Systems (SAPHYS)`, different design configurations are compared and discussed. In this paper we present some of the proposed design configurations and discuss their benefits and drawbacks. Simplified expressions for system efficiency for the different configurations are presented. These expressions are based on average efficiencies for the solar cells, the electrolyzer, the batteries, the hydrogen storage and the fuel cells. Mean fractions of energy passing through the energy storages are also assumed. From considerations in the paper one conclusion becomes apparent, i.e. the direct use of the energy should be maximized. Another conclusion is that one of the most important factors in Solar Photovoltaic Hydrogen Power Systems is the solar cell efficiency. This point seems to be ...

KoreaScience (Korea)

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British Library Electronic Table of Contents (United Kingdom)

Rare-earth oxides are doped into ZnO varistors as grain growth inhibitors for increasing the varistors' voltage gradients. However, their leakage currents become large and their nonlinear coefficients decrease at the same time. The reasonable explanation for such a phenomenon has not yet been available. In this paper, the temperature dependences of varistor samples' leakage currents are investigated, which reveal that the increased leakage currents of ZnO varistors with Y2O3 doping are mainly due to the bypass paths through the intergranular materials at grain corners.

Energy Technology Data Exchange (ETDEWEB)

In this paper the availability and properties of radioisotopes for both radioimmunodiagnosis (RAID) and radioimmunotherapy (RAIT) are discussed. Examples are provided for radioisotopes available via direct production in nuclear reactors and accelerators or as daughters obtained from radionuclide generator systems whose parents are either reactor or accelerator produced. Important factors which must be considered for the use of a particular radioisotope include availability, the physical half-life and decay properties, and chemical versatility for protein attachment. Although both direct'' and indirect'' methods are available for attachment of radioisotopes to antibodies, this broad field of research is not reviewed in detail. Practical issues related to the availability and use of a variety of radionuclides are described. 47 refs., 5 tabs.

Energy Technology Data Exchange (ETDEWEB)

As an interim report on the study on vibration of transmission lines when gust is blowing, this paper introduces events of confused and other contacts between transmission lines, photographing of transmission line vibration, physical measurement on transmission line response, and development of simulation software. Events of confused contacts of high-voltage transmission lines with overhead ground wires have the following common conditions: gust blows nearly perpendicularly to the line direction; no obstacles exist in upwind directions; the wind blows upward or downward against high-voltage transmission lines; and size of the high-voltage transmission lines is 25 mm{sup 2}. According to photographs of transmission line vibration, it appears that gust caused a high-voltage transmission line on the upwind side to jump resulting in confused contact with the ...

International Nuclear Information System (INIS)

A 2-stage cold (non-tritium) PMR system was tested with the ITER mix in 61 days of continuous operation. No decrease in performance was observed over the duration of the test. Decontamination factor (DF) was found to increase with decreasing inlet rate. Decontamination factors in excess of 1.4x10"5 were obtained, but the exact value of the highest DF could not be determined because of analysis limitations. Results of the 61-day test were used to design a 2-stage PMR system for use in tritium testing. The PMR system was scaled up by a factor of 6 and built into a glovebox in the Tritium Systems Test Assembly (TSTA) of the Los Alamos National Laboratory. This system is approximately 1/5"t"h of the expected full ITER scale. The ITER mix was injected into the PMR system for 31 hours, during which 4.5 g of tritium were processed. The 1"s"t stage had DF =200 and the ...

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Cell voltage monitoring (CVM) systems are essential for the operation of fuel cell stacks and some battery systems, in the field as well as in the laboratory, because they allow the diagnosis and correction of problems that would otherwise go unnoticed and cause impaired performance or even permanent damage. A robust, safe, and low-cost design for a CVM unit is presented, using electromechanical relays as multiplexing switches. Some examples from the application of the unit on the University of Delaware's fuel cell battery hybrid buses are presented, including its use in automatically correcting anode flooding and diagnosing air channel blockage. (author)

International Nuclear Information System (INIS)

In this paper, an improved soft switched two cell interleaved boost AC/DC converter with high power factor is proposed and investigated. A new auxiliary circuit is designed and added to two cell interleaved boost converter to reduce the switching losses. The proposed auxiliary circuit is implemented using only one auxiliary switch and a minimum number of passive components without an important increase in the cost and complexity of the converter. The main advantage of this auxiliary circuit is that it not only provides zero-voltage-transition (ZVT) for the main switches but also provides soft switching for the auxiliary switch and diodes. Though all semiconductor devices operate under soft switching, they do not have any additional voltage and current stresses. The proposed converter operates successfully in soft switching operation mode for a wide range of input voltage level and the load. In addition, ...

Energy Technology Data Exchange (ETDEWEB)

This paper introduces a novel three-phase power flow approach for unbalanced radial distribution systems. The proposed approach is developed based on the loop frame of reference, rather than the traditional bus frame of reference. On the basis of the loop frame of reference, a simple direct iterative method in impedance form is applied. Basic graph theory and injection current technique are also applied in the proposed approach. The clear theoretical foundation and the simple topology of the radial distribution network make the proposed method efficient and reliable. To demonstrate the better convergence performance and the efficiency of the proposed approach, four three-phase IEEE test feeders are used for comparisons. The test results show that the proposed method has robust convergence characteristics and high performance, especially for large-scale radial distribution systems. (author)

Energy Technology Data Exchange (ETDEWEB)

Problems relating to electromagnetic compatibility and power quality were discussed, combined with a discussion of the role that consulting engineers can play in resolving them. The need for the consulting engineer to be aware of design specifications of equipment was considered essential. Similarly, the interrelationship between installations using variable speed drives, halogenous lighting systems, capacitor banks, high-voltage power lines, power transformers, etc., and the need for familiarity with the operating characteristics of different types of power systems were stressed as key ingredients to success in ascertaining events and causes of equipment failure or power system problems on the network. The main sources of disturbances, impact of voltage variations, the importance of controlling voltage imbalance, and system protection were ...

International Nuclear Information System (INIS)

In recent years, there has been a significant increase in concern over the health and safety aspects of high voltage transmission lines (HVTL). The majority of research has focused on effects directly or indirectly involved with the central nervous system, including physiological, ultrastructural, and biochemical alterations, changes in blood composition, behaviour, reproduction, and development. Several recent epidemiological reports have presented preliminary data suggesting an increase in the incidence of cancer among children and adults exposed to magnetic fields through living close to various types of electrical power lines or devices. With the increase in environmental concerns there has been a concomitant consideration of biological effects and health implications related to presently existing HVTL and those planned in the future. It was concluded that the electric and magnetic field strengths and the electrical ...

Energy Technology Data Exchange (ETDEWEB)

The B-Factory which is constructed by National Laboratory for High Energy Physics is the device for elucidating the breakdown of symmetry of matter and antimatter by studying the behavior of B mesons which are generated in large quantity when the electrons and the positrons which are accelerated to light velocity level are collided. In order to maintain electron beam-positron beam bunch circling the ring at light velocity stably, the instability of the coupled bunch must be overcome. For this purpose, the ultrahigh speed beam position digital feedback control system was developed. This system is composed of the high speed input-output substrate using GaAs LSI, the feedback computation substrate using complementary metal oxide semiconductor and the memory mounted on it, and the real time operation device. The development of both substrates and their functions are explained. The real time data collection and the change of ...

Energy Technology Data Exchange (ETDEWEB)

Four 10 MW, highly-stabilized power supply modules have been installed at the National High Magnetic Field Laboratory in Tallahassee, FL, to energize water-cooled, resistive, high-field research magnets. The power supply modules achieve a long term current stability if 10 ppM over a 12 h period with a short term ripple and noise variation of <10 ppM over a time period of one cycle. The power supply modules can operate independently, feeding four separate magnets, or two, three or four modules can operate in parallel. Each power supply module consists of a 12.5 kV vacuum circuit breaker, two three-winding, step-down transformers, a 24-pulse rectifier with interphase reactors, and a passive and an active filter. Two different transformer tap settings allow rated dc supply output voltages of 400 and 500 V. The rated current of a supply module is 17 kA and each supply module has a one-hour overload capability of 20 kA. The ...

Energy Technology Data Exchange (ETDEWEB)

The standard protocol in multislice spiral CT (MSCT) angiography for coronary arteries with fixed tube current-time settings leads to an overexposure and thus to an unnecessary high radiation dose in patients with lower weight when compared to heavier patients. The purpose of this study was to estimate the effect of reducing the radiation dose by adapting the tube current-time settings individually. Fifty patients underwent retrospectively ECG-gated MSCT of the heart. In 25 patients (group A{sub 1}) a standard protocol with constant tube current-time settings was used (4 x 1-mm collimation, 120 kV, 400 mAs{sub eff}). Subsequently, artificial image noise was added to the data of these patients simulating a directive for weight-adapted tube current-time settings (group A{sub 2}). In the other 25 patients (group B) an alternative protocol with individually weight-adapted tube ...

International Nuclear Information System (INIS)

With the increasing use of high voltage alternating current (HVAC) transmission lines there is a growing concern among the public about possible human health effects resulting from exposure to the electric fields associated with these lines. While there is no definitive evidence of such effects, mounting public fear and activism over hypothesized health risks is already causing delays in the licensing and constuction of major power transmission facilities, and is encouraging the formation of regulatory policy. This paper briefly reviews the concerns, biological effects data and standards for HVAC transmission lines.

Energy Technology Data Exchange (ETDEWEB)

Results obtained on induced current and voltage caused by a high voltage transmission lines running parallel at a trolley bus contact lines, are presented. A computer program in Basic language, was developed to calculate the electric induction, problems of safety, a theoretical development and mathematical model of the electric factors between two lines (inductor and induced) are also discussed. 11 figs., 1 tab., 8 refs.

Energy Technology Data Exchange (ETDEWEB)

A delta connected, resonant snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the dc supply voltage through the main inverter switches and the auxiliary switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter.

Science.gov (United States)

The identification of crystallographic phases in the scanning electron microscope (SEM) has been limited by the lack of a simple way to obtain electron diffraction data of an unknown while observing the micro structure of the specimen. With the development of Charge Coupled Device (CCD) based detectors, backscattered electron Kikuchi patterns (BEKP), alternately referred to as electron backscattered diffraction patterns (EBSP), can be easily collected. Previously, BEKP has been limited to crystallographic orientation studies due to the poor pattern quality collected with video rate detector systems. With CCD detectors, a typical BEKP can now be acquired from a micron or sub-micron-sized crystal using an exposure time of 1-10 seconds with an accelerating voltage of 10-40 kV and a beam current as low as 0.1 nA. Crystallographic phase analysis using BEKP is unique in that the properly equipped SEM permits high magnification ...

Energy Technology Data Exchange (ETDEWEB)

Operating the Stanford Linear Collider (SLC) at 120Hz repetition rate requires the presence of two bunches in both the electron and the positron damping ring. The {pi}-mode instability, a coupled bunch instability where the two bunches oscillate with a phase difference of 180{degrees}, had been observed in both rings with low current thresholds of 7{sup *}10{sup 9} particles per bunch. To avoid the instability, the RF system had to be operated in ways which in general reduced the cavity gap voltages and required constant operational attention. For the 1992 running cycle a passive cavity was installed and successfully tested. It is tuned to the frequency of the lower synchrotron oscillation sideband of an odd revolution harmonic. The impedance of the cavity then damps {pi}-mode oscillations very similar to the Robinson damping provided by the main RF cavities which damps O-mode synchrotron oscillations. In this report we ...

Energy Technology Data Exchange (ETDEWEB)

Abstract: We report for the selective-area chemical synthesis of semiconductor single-crystal organic nanowires of silver-tetracyanoquinodimethane (Ag-TCNQ). Straight and smooth Ag-TCNQ nanowires can be produced and patterned on micrometer and nanometer scale on silicon substrates covered with a thin layer of Ag film through the reaction of TCNQ and Ag in a simple gas-solid chemical reaction process. Ag-TCNQ nanowires are characterized by UV-vis, IR and Raman spectroscopy, respectively. The Ag-TCNQ nanowires grows preferentially along the [100] direction of strong - stacking of Ag-TCNQ molecules. Nanodevices based on these nanowires are fabricated using focus ion beam (FIB) technique. Electrical properties are characterized and I-V hysteresis is observed, which shows memory effect with electrical switching of three orders on-off ratio. These nanowires could be potential for use in optical storage, ultrahigh-density nanoscale memory and logic ...

Science.gov (United States)

This current awareness bulletin announces on a semimonthly basis the current worldwide information entered into the Energy Data Base on all aspects of direct energy conversion. Categories include photovoltaic conversion, magnetohydrodynamic generators, electrohydrodynamic generators, thermoelectric generators, thermionic converters, fuel cells, and miscellaneous converters. An abstract is inclluded with each citation. (WHK)

KoreaScience (Korea)

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International Nuclear Information System (INIS)

Closing and breaking of current in microsecond megaampere plasma opening switches are considered. Conductivity current scaling in the switch due to plasma acceleration by a magnetic piston is discussed and compared with experimental data. Two ways of determining the width of a current channel are taken up. This channel results from the diffusion of the magnetic field in the plane of the piston followed by the convective ejection of the field frozen in the accelerated plasma flow behind the shock wave into the bridge. Based on experimental data, a scaling law for the voltage on the switch according to the switch parameters is derived. The problem of reverse closing, which limits the efficiency of storage energy extraction into the load, is considered

DEFF Research Database (Denmark)

This paper presents a new grid connected inverter for fuel cells. It consists of a two stage power conversion topology. Since the fuel cell operates with a low voltage in a wide voltage range (25 V-45 V) this volt- age must be transformed to around 350-400 V in order to invert this dc power into ac power to the grid. The proposed converter consists of an isolated dc-dc converter cascaded with a single phase H-bridge inverter. The dc-dc converter is a current-fed push-pull converter. A new dedicated voltage mode startup procedure has been developed in order to limit the inrush current during startup. The inverter is controlled as a power factor controller with resistor emulation.Experimental results of converter efficiency, grid performance and fuel cell response are shown for a 1 kW prototype. The proposed converter exhibits a high efficiency in a wide power range (higher than 92%) ...

Energy Technology Data Exchange (ETDEWEB)

Four HVDC (high voltage DC) {+-} 250kV submarine OF (oil-filled) cables are to be installed each capable of 1.4-million kW for one dipole channel and two returns for forwarding to Yura Switchyard a part of the power to be generated by a Tachibanawan coal-fired power plant to open in 2000. The first cable is now being laid. They are to cover a distance of 48km on the sea bottom, and their 190mm diameter is the largest in the world and this decreases the required number of cables for a reduction in the construction cost. The installation is executed by use of a dedicated cable laying ship loaded with cables. The ship is equipped with five thruster screws by adjusting which a cable is fed into the sea and laid on the bottom with high positional accuracy in all directions, and with a 10m-accurate DPS (Dynamic Positioning System) besides GPS (Global Positioning System). Operating on the sea bottom is a ...

Energy Technology Data Exchange (ETDEWEB)

As a central supervision authority the National Electrical Safety Board (Elsaekerhetsverket) has the main responsibility for the safety of high voltage power lines and other power electric equipment. It is therefore also responsible for questions concerning the effects of power frequency magnetic fields on the environment. According to the rules it is not allowed to draw overhead power lines with a voltage exceeding 1000 V above buildings. Their minimum distance to buildings must not be below 5 m. For regions comprised by rural development plans the directions prescribe a minimum distance of 10 m between buildings and high voltage transmission lines with a voltage of 55 kV or more. The publication of two large epidemiological studies about exposure to magnetic fields and cancer in Sweden in autumn 1992 has brought magnetic fields problems to general notice again. A statement on ...

Energy Technology Data Exchange (ETDEWEB)

The feasibility of using of current-biased superconducting strips for radiation detection is investigated. Narrow Ta strips are exposed to 5.5 MeV [alpha]-particle radiation and the rise-time of the induced voltage pulses is measured as function of temperature and bias current. The rise-time of the voltage signal strongly depends on the site on the strip which is hit by the [alpha]-particle. In order to determine the spatial resolution of a superconducting strip detector, position-sensitive measurements were performed. The maximum lateral resolution estimated so far is 25[mu]m in a 7[mu]m wide, 340 nm thick and 0.6 mm long Ta-strip. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Developing models for the electrical behavior of exploding bridgewire circuits requires high-quality data of a type not usually generated in routine tests of detonator hardware. To obtain a precise measurement of the time of bridgewire burst relative to current start, one must simultaneously record the current, i, and either di/dt or the voltage across the bridgewire. To fully develop and test a model it is also necessary to vary the bridgewire cross sections and geometry, firing circuit characteristics and charging voltage for the firing circuits over as wide a range as possible. As a part of developing an electrical model for aluminum and copper bridgewires, we have conducted parameter studies on some flat copper and aluminum bridgewires. Most of the work was done on aluminum bridgewires, with a few experiments on copper. We will report the experimental results from these studies and compare them with ...

Energy Technology Data Exchange (ETDEWEB)

Midway Labs currently produces a 335x concentrator module that has reached as high as 19{percent} active area efficiency in production. The current production module uses the single crystal silicon back contact SunPower cell. The National Renewable Energy Lab has developed a multi junction cell using GalnP/GaAs technologies. The high efficiency ({gt}30{percent}) and high cell voltage offer an opportunity for Midway Labs to develop a tracking concentrator module that will provide 24 volts in the 140 to 160 watt range. This voltage and wattage range is applicable to a range of small scale water pumping applications that make up the bulk of water pumping solar panel sales. {copyright} {ital 1997 American Institute of Physics.}

Science.gov (United States)

We report on the formation of current blocking regions by O2 plasma treatment to reduce current crowding at the active region above the p-type electrodes of GaN-based vertical light emitting diodes (LEDs). The forward voltage and reverse current (at -5 V) of the plasma-treated LEDs slightly increase with increasing aging time. The output power (at 350 mA) of the plasma-treated LEDs is enhanced by 26% as compared to that of reference LEDs and is comparable to that of LEDs with SiO2 current blocking layers. It is shown that the output power (at 700 mA) of the plasma-treated LEDs is degraded by less than 2% of the initial value after 500 h.

Science.gov (United States)

A novel reactor combining a flame-deposited nanostructured titanium dioxide film and a set of embedded ceramic electrodes was designed, developed and tested for degradation of methyl tert-butyl ether (MTBE) in water. On applying a voltage to the ceramic electrodes, a surface coro...

International Nuclear Information System (INIS)

The first long pulse production of high power D"- ion beams has been demonstrated in the JT-60 U negative ion sources, each of which was designed to produce 22 A, 500 keV D"- ion beams. Voltage holding capability and the grid power loading were examined for long pulse production of high power D"- ion beams. From the correlation between voltage holding and the light intensity of cathodoluminescence from the Fiber Reinforced Plastic insulators, the acceleration voltage for stable voltage holding capability was found to be less than 320-340 kV where the light was sufficiently suppressed. By tuning the extraction voltage, the grid power loadings in the ion sources were decreased to the allowable levels for long pulse injection without a significant reduction of the beam power. After tuning the acceleration and extraction voltages, D"- ion beams of 12.5 and 9.8 A ...

UK PubMed Central (United Kingdom)

The Mitochondrial Free Radical Theory of Aging (MFRTA) is currently one of the most widely accepted theories used to explain aging....Full Text Available

Science.gov (United States)

In 1978, China's coal mining industry achieved an output of 618,000,000 metric tons of raw hard coal, an increase of 128,000,000 tons compared with 1977. This has been achieved primarily by increased new mine development and the modernizaion and expansion of existing mines. While 96% of China's coal is currently produced from underground mines, only 33% of this output is from full mechanized operations, i.e., mechanized longwall retreat faces. Over 1% is produced by hydraulic mining. The current Ten-Year Plan (1975-1985) established that the major thrust of new development and activity should be made particularly in the Shandong, Anhui, Henan, Guizhou, and Yunnan provinces. China is presently concentrating on the construction/enlargement of eight major coal mining centers, mainly in the north and northeast of the country, each with a designed capacity in excess of 10,000,000 tons a year. China has elected to import large ...

International Nuclear Information System (INIS)

Full text. Here we present a status report of the Schenberg antenna, which started commissioning runs in September 2006 under the full support of FAPESP. In its first commissioning runs we tested three preliminary parametric transducer systems, which did not achieve a high enough performance for placing the antenna sensitivity in the range of the calibrator capacitor. Instead of improving the calibrator, making it capable of introducing a larger input force, we decided to go to a radical upgrading operation: replacing the three transducers for a complete set of six transducers, with better sensitivity and arranged according to the truncated icosahedron configuration, plus two extra ones; starting to install the dilution refrigerator; installing wires, cables, and amplifiers for the complete set of transducer circuits; and a new suspension and vibration isolation system for the cabling and microstrip antennas. We also have been developing a new ...

Energy Technology Data Exchange (ETDEWEB)

A highly efficient integrated energy conversion system is built based on a methane catalytic decomposition reactor (MCDR) together with a direct carbon fuel cell (DCFC) and an internal reforming solid oxide fuel cell (IRSOFC). In the MCDR, methane is decomposed to pure carbon and hydrogen. Carbon is used as the fuel of DCFC to generate power and produce pure carbon dioxide. The hydrogen and unconverted methane are used as the fuel in the IRSOFC. A gas turbine cycle is also used to produce more power output from the thermal energy generated in the IRSOFC. The output performance and efficiency of both the DCFC and IRSOFC are investigated and compared by development of exact models of them. It is found that this system has a unique loading flexibility due to the good high-loading property of DCFC and the good low loading property of IRSOFC. The effects of temperature, pressure, current densities, and ...

CERN Document Server

The PEP-II storage rings at SLAC each have 3492 'buckets' into which electrons and positrons can be injected into the high- and low-energy rings. Equipment to measure the currents of all the individual buckets was originally provided by the Lawrence Berkeley Laboratory and is implemented in VXI-based hardware. Data from this equipment as well as high precision direct current measurement provide the hard data for the Bunch Injection Controller. A large number of parameters determined by injection design considerations as well as set by operators for different circumstances are also used by the software algorithms to determine the desired bucket injection order and charge quantity for each injection pulse. These requests are then passed on to the venerable SLAC master pattern generator, which provides beams for other applications as well. This highly visible and highly successful system is implemented ...

International Nuclear Information System (INIS)

The design and analysis of a high brightness electron beam experiment under construction at Sandia National Laboratory is presented. The beam energy is 12 MeV, the current 35 endash 40 kA, the rms radius 0.5 mm, and the pulse duration FWHM 40 ns. The accelerator is SABRE [J. Corley, J. A. Alexander, P. J. Pankuch, C. E. Heath, D. L. Johnson, J. J. Ramirez, and G. J. Denison, in Proceedings of the Eighth International IEEE Pulsed Power Conference, San Diego, California, 1991 (IEEE, New York, 1991), p. 920], a pulsed inductive voltage adder, and the electron source is a magnetically immersed foilless diode. This experiment has as its goal to stretch the technology to the edge and produce the highest possible electron current in a submillimiter radius beam. copyright 1996 American Institute of Physics.

Energy Technology Data Exchange (ETDEWEB)

Comparative indices are given for the efficiency of phase control of remote-controlled self-compensating high-voltage transmission lines, including a consideration of the power transfer effect between high-voltage line circuits. A description is given of certain circuit variations for performing the technical means of regulating phase shift, and their characteristics which make it possible to evaluate the effect of the phase regulators on the electrical transmission system are also given. An examination is made of problems concerned with the design of lines, relay protection, computation of transfer processes and dynamic stability as well as the computation of over-voltage when shutting off short circuits during amplified electromagnetic ties between line circuits.

Energy Technology Data Exchange (ETDEWEB)

Polysilicon thin-film technology has become of great interest due to the demand for large area electronic devices. Active matrix liquid crystal displays (AMLCDs) and active matrix organic light emitting displays (AMOLEDs) are among the fields where polysilicon thin-film transistors (poly-Si TFTs) are most commonly used. Such devices, generally, require analog signal processing. This fact makes the performance of basic analog blocks, such as current mirrors implemented with poly-Si TFTs, crucial. This paper examines the performance of various current mirror designs through simulation. Finally, a novel design of a current mirror is proposed aimed to be used in low voltage applications.

UK PubMed Central (United Kingdom)

The rapidly activating and inactivating voltage-dependent outward K⁺ (Kv) current, I_A, is widely expressed in central and peripheral neurons. I_A has long been...Full Text Available

International Nuclear Information System (INIS)

The influence of MeV electrons irradiation on the gate oxide layers of hydrogenated polysilicon thin film transistors (TFTs) was investigated by measuring gate leakage currents and threshold voltages. The experimental data revealed a decrease of oxide trap density and increase of positive oxide charge. Improvement in the interface roughness and in the oxide quality near the bottom interface was observed.

Energy Technology Data Exchange (ETDEWEB)

GaAs-based dc high voltage photoguns used at accelerators with extensive user programs must exhibit long photocathode operating lifetime. Achieving this goal represents a significant challenge for proposed high average current facilities that must operate at tens of milliamperes or more. This paper describes techniques to maintain good vacuum while delivering beam, and techniques that minimize the ill effects of ion bombardment, the dominant mechanism that reduces photocathode yield of a GaAs-based dc high voltage photogun. Experimental results presented here demonstrate enhanced lifetime at high beam currents by: (a) operating with the drive laser beam positioned away from the electrostatic center of the photocathode, (b) limiting the photocathode active area to eliminate photoemission from regions of the photocathode that do not support efficient beam delivery, (c) using a large drive laser beam to ...

Environmental Research Database

Summary'THE ROLE OF THE UK PLANNING SYSTEM IN PROTECTING AND ENHANCING SOILS PROJECT REF: UKLQ01 APRIL 2004 INTRODUCTION Soil has long been overlooked in environmental planning. Whilst it has sometimes benefited from indirect protection, until recently its importance and vulnerability have not been reflected in more explicit strategies. This study explored the current and potential role of the planning system in protecting and enhancing soils. Soil is the physical material that covers much o [continued...]DescriptionSNIFFER has commissioned this study on behalf of SEPA, SNH, EHS and the Environment Agency for England and Wales. These UK agencies have an interest in protecting soil quality through a combination of direct regulation of emissions to land, protection of designated sites of special value or sensitivity and engaging other regulatory regimes such as land use planning. All UK environment ...

Energy Technology Data Exchange (ETDEWEB)

We describe a liquid hydrogen droplet as an optical cavity via whispering gallery modes. We show that the droplet leads to an ultrahigh-cavity-Q value of 2.5x10{sup 9} in visible region. We show also that the high-Q droplet results in a huge Raman nonlinearity, generating a stimulated Raman comb series covering whole visible region.

Energy Technology Data Exchange (ETDEWEB)

The current status of rare B decays is reviewed based on recent observation of the penguin-diagram decay B {yields} K{sup *}{gamma} at CLEO. Rare B decays provide valuable information on the Standard Model parameters, and also could be a source of direct CP violation. It is emphasized that new physics beyond the Standard Model can appear in rare B decays, in some cases more drastically than in the CP Asymmetry of the B system. Inclusive measurement of the radiative transition b {yields} s{gamma} is promising. Hadronic penguin modes are very close to being observed at CLEO, and a discovery might be just around the corner. (author). 48 refs., 6 figs., 4 tabs.

Energy Technology Data Exchange (ETDEWEB)

Acrylonitrile is a versatile intermediate and is produced by the Sohio ammoxidation process world-wide at a level of 8 billion pounds per year. In the catalytic process, propylene, ammonia and air are converted to acrylonitrile directly. The most widely used catalysts are mixed metal molybdates or antimonates. The current investigation deals with metal tellurates as possible low temperature ammoxidation catalysts. Of the catalysts investigated, iron-selenium-tellurates are of particular interest since they exhibit good ammoxidation activity already at 320/sup 0/C which is about 100/sup 0/C lower than the temperature required for molybdate or antimonate systems. Mechanistically, the tellurates behave more similarly to the antimonates than the molybdates. 3 tabs., 4 figs., 13 refs.

Energy Technology Data Exchange (ETDEWEB)

A high voltage self-blowing circuit breaker with closing resistors is equipped with an auxiliary contact inserted in the trip control circuit of an electrical circuit breaker. The auxiliary contact is actuated by the mechanical control rod of the circuit breaker in such a way as to prevent any operator closing error. A high-speed mechanism is inserted in the link system connecting the control rod and the auxiliary contact, with dead travel to delay closing of the auxiliary contact when a closing operation takes place and to prevent a tripping order from being transmitted too early. Such an early transmission would be liable to cause a flashover on the inserter contacts and damage to the circuit breaker.

International Nuclear Information System (INIS)

Considerations for longevity of nuclear facilities and ease of decommissioning are of great importance for future nuclear power plants. To this end, a concept of an optimal structural concept for nuclear reactor buildings has been studied: the main feature of this concept is to utilize large-sized, light weight prefabricated members with ultrahigh strength materials. The following two items have been selected to study the prospective structure: (1) Applicability of ultrahigh strength materials for reinforced concrete shear walls (2) Construction using large sized prefabricated members As the first step (1), material and structural tests using ultrahigh strength materials, and the subsequent analysis of those tests for reinforced concrete shear walls, has been conducted. The positive results of this study show a bright future for the use of ultrahigh strength materials for the reinforced concrete shear ...

International Nuclear Information System (INIS)

A study has been performed of the initial corrosion of support structure alloys in crevices of various geometries, when galvanically coupled to alloy 600. Corrosion rates were monitored continuously by measuring the galvanic current flowing in each couple, transduced by a zero impedance ammeter. Experiments were performed in a single-pass flowing electrolyte system, with AVT water pumped through alloy 600 tubing past the orifice of each crevice. Fourteen crevices were studied simultaneously in two parallel flow arms containing seven specimens each. The steady state AVT water pH/hydrazine/oxygen concentrations were controlled by microcomputer, allowing the effect of secondary water chemistry on the corrosion rate to be studied easily. Control of the crevice electrolyte composition was achieved by separately pumping electrolyte, at a low rate, directly into the crevices of the seven specimens in the lower flow arm. In ...

Energy Technology Data Exchange (ETDEWEB)

Improvements in electric submersible pumping systems have resulted in a demonstrated downhole running life of one year for low horsepower units operating in 180 C brine. The implementation of a prototype pressurized lubrication system to prevent brine intrusion and loss of lubricating oil from the motor and protector sections has been successfully tested. Second generation pressurized lubrication systems have been designed and fabricated and will be utilized in downhole production pumping tests during FY84. Pumping system lifetime is currently limited by available power cable designs that are degraded by high-temperature brine. A prototype metal-sheathed power cable has been designed and fabricated and is currently undergoing destructive and nondestructive laboratory testing. This cable design has the potential for eliminating brine intrusion into the power ...

International Nuclear Information System (INIS)

In this paper experimental observations and a theoretical analysis of periodic radiation bursts and macropulse formation in the start-up phase of a free-electron laser (FEL) oscillator are presented. This microwave FEL uses a long pulse electron beam with a slowly decaying voltage. The output radiation consists of a superposition of bell-shaped macropulses, each of which is composed of a periodic sequence of short micropulses. The micropulses are separated by a cavity round-trip time. Each bell-shaped macropulse has a random start-up time and amplitude. The startup of the radiation macropulses is correlated with random current spikes on the continuous electron beam. The observed macropulse signal agrees with a theoretical calculation of the impulse response of the FEL oscillator when the shift in the FEL resonance frequency arising from the slow voltage drop of the electron beam is included in the analysis. Possible ...

Science.gov (United States)

... geographically flexible rapid- deployment forecasting system that directly leverages the CORIE modeling and information management capabilities. ...

Energy Technology Data Exchange (ETDEWEB)

Various electrochemical capacitors (ultracapacitors) are being developed for hybrid vehicles as candidate power assist devices for the fast response engine. The primary functions of the ultracapacitor are to level the dynamic power loads on the primary propulsion device and recover available energy from regenerative breaking during off-peak power periods. Ultracapacitors show promise toward being able to accept high regenerative pulses while exhibiting very high cycle life. This paper will present test data from selected US Department of Energy (DOE) supported ultracapacitor projects designed to meet the fast response engine requirements. Devices containing carbon, conducting polymers, and metal oxide electrode materials in combination with aqueous or organic electrolytes are being supported by the DOE. This paper will present and discuss testing data obtained from recent prototype capacitors supplied by Maxwell Energy Products, Inc., SAFT America, Inc., Federal Fabrics-Fibers and the ...

International Nuclear Information System (INIS)

The barrier glow discharge between two planar electrodes, covered with dielectric, is studied under high-voltage pulsed power supply. Wide applications of such type of discharges, in particular, for ozone production, stimulated a number of investigations in this direction. In this work we investigated the dependence of ozone concentration on the duration and the rate of pulse rise of the applied voltage. The thyristor converter circuit with the shortening of input pulses on the base of the saturable throttle was used for the realization of this task. The output pulses with amplitude up to 15 kV, repetition frequency of 1 kHz, pulse duration of 0.3 #mu#s (or 7 #mu#s) and the rate of pulse rise of 0.1 #mu#s were generated with this scheme. Measurements of the ozone concentration produced in the air mixture have shown that its value increased by factor two with variation of the rate of pulse rise from 0.5 #mu#s to 0.1 #mu#s ...

Energy Technology Data Exchange (ETDEWEB)

This paper presents the technical and economic studies performed by CEMIG, Companhia Energetica de Minas Gerais, Brazil, concerning the use of closing resistor in its extra-high voltage (EHV) breakers. The analysis emphasizes the advantages which could be achieved with the elimination of the resistor as far as costs and reliability are concerned. This evaluation was motivated by two 500 kV breaker failures resulting from the breakdown of the closing resistor operation mechanism. These occurrences resulted in operative restriction for CEMIG EHV system. The analysis demanded a review of the capability criteria of silicon carbide (Si C) gap arresters, which are still greatly used in CEMIG EHV System, and of the procedures to be applied when carrying out the transient studies. The investigation resulted in the prompt removal of closing resistors from circuit breakers in CEMIG extra-high voltage ...

Energy Technology Data Exchange (ETDEWEB)

Mixed-conducting ceramic oxides have potential uses in high-temperature electrochemical applications such as solid oxide fuel cells, advanced batteries, sensors, and oxygen-permeable membranes. The Sr-Fe-Co-O system combines high electronic/ionic conductivity with appreciable oxygen permeability at elevated temperatures. Dense ceramic membranes made of this material can be used to separate high-purity oxygen from air without the need for external electrical circuitry, or to partially oxidize methane to produce syngas. Samples of Sr{sub 2}Fe{sub 3{minus}x}Co{sub x}O{sub y} (with x = 0, 0.6, 1.0, and 1.4) were prepared by solid-state reaction in atmospheres with various oxygen partial pressures (pO{sub 2}) and were characterized by X-ray diffraction, scanning electron microscopy, and electrical conductivity measurements. Phase components of the samples are dependent on cobalt concentration and synthesis pO{sub 2}. Total conductivity increases with increasing ...

Energy Technology Data Exchange (ETDEWEB)

This paper describes the development and testing of a system to provide isolated power to the cathode-subsystem electronics of an x-ray tube. These components are located at the cathode potential of several hundred kilovolts, requiring a supply of power isolated from this high voltage. In this design a fiber-optically connected photonic power system (PPS) is used to recharge a lithium-ion battery pack, which will subsequently supply power to the cathode-subsystem electronics. The suitability of the commercially available JDSU PPS for this application is evaluated. The output of the ppe converter is characterized. The technical aspects of its use for charging a variety of Li-Ion batteries are discussed. Battery charge protection requirements and safety concerns are also addressed.

Energy Technology Data Exchange (ETDEWEB)

It is shown that a gun similar to that in the SSPX could demonstrate the high fields required for Pulsed Spheromak reactors merely by prolonging the pulse. Important considerations are choosing the voltage to exceed ohmic losses; designing the gun to avoid wasteful short-circuiting of current within the gun; and the injection efficiency factor, f, determined by the ''sag'' in the profile of {lambda} = {mu}{sub o}j/B. Typically f = 0.75 in experiments, giving an overall efficiency > 50 % if short-circuiting is avoided. Theoretical transport models agree qualitatively with the need for a finite gradient in h to pump in helicity by current-driven tearing modes and suggest that pressure-driven resistive modes would not compete with current-driven modes during a buildup to ohmic ignition.

Energy Technology Data Exchange (ETDEWEB)

Direct electric heating by passing an electrical current directly through a bed of adsorbent may prove to be an efficient means of regenerating activated charcoal in continuous and batch adsorption processes. Obvious advantages of this type of regeneration are its almost complete lack of inertia, which makes it possible to reduce the number and dimensions of the adsorbers, and its highly efficient use of energy due to the small number of steps in the conversion of the energy, as well as the reduction of heat losses involved in warming the structure and making up for losses to the surroundings. The authors consider the kinetics of direct electric heating of a stationary bed of activated charcoal not containing adsorbed substances.

Energy Technology Data Exchange (ETDEWEB)

Density functional theory (DFT) calculations using plane-wave methods were performed for Li2TMPO4F, LiTMPO4F, and TMPO4F (TM=V, Mn, Fe, Co, Ni) to address their feasibility as high-voltage cathode materials for Li ion batteries. We computed their structures, average open circuit voltages, and thermal stabilities for step-wise lithiation/delithation (discharge/charge) reactions. The calculations suggest that associated unit cell volume changes are sufficiently small on average that they should not be a significant detriment to the mechanical stability of the cathode. In the nickel case, the calculated volume change deviates from the series by increasing during the first delithiation step. Furthermore, the volume increases for all these materials during the second delithiation step. It appears that the relative volume expansion in the series during delithiation is directly correlated to the degree of d-p rehybridization. ...

Energy Technology Data Exchange (ETDEWEB)

Noncollinear (NC) magnetism is common in nature, especially when there exist geometrical frustration and chemical imparity in the system. In this work we studied the NC magnetism and the response to external magnetic fields in surfaces and interfaces of transition metals by using an semi-empirical tight-binding (TB) method that parameterized to the ab initio TB-LMTO calculations. We implemented this method to study two systems. The first one is the system of 6 Mn monolayers on Fe(001) substrate. Due to the complex structure and magnetic properties of Mn, we found 23 collinear magnetic configurations but only one NC configuration. The collinear ground state has a layered antiferromagnetic (AFM) coupling which agrees with previous experiments and calculations. In the NC configuration the local AFM coupling in the Mn layers is preserved, but the surface is 90 degree coupled to the substrate. Similar to the experiment in ...

CERN Document Server

Each of the two LHC injection kicker magnet systems must produce a kick of 1.3 T.m with a flattop duration variable up to 7.86 microseconds, and rise and fall times of less than 900 ns and 3 microseconds, respectively. A kicker magnet system consists of four 5 Ohm transmission line magnets with matching terminating resistors, four 5 Ohm Pulse Forming Networks (PFN) and two Resonant Charging Power Supplies (RCPS). Nine PFNs, together with associated switch tanks, and dump switch terminating resistors have been built at TRIUMF and all have been tested at high voltage (54 kV) to ensure that the performance is within specification. This paper describes the HV measurements, compares these results with low voltage measurements and analyses the pulse performance of the PFNs. The measurements are compared with results from PSpice simulations and small discrepancies between the predictions and measurements are ...

Energy Technology Data Exchange (ETDEWEB)

This report presents information obtained during five different studies of field effects from high voltage transmission lines performed at EPRI's High Voltage Transmission Research Center. The first study is the development of a methodology for the evaluation of the expected frequency of occurrence of specific short-term effects of spark discharges and induced currents caused by overhead high voltage transmission lines. The methodology is divided into the analysis of the expected frequency of occurrence of situations in which induction effects may occur, and the analysis of the expected severity of the effect. The second study is of the electric field in the surface and on the immediate proximity of the strands of stranded conductors used for overhead high voltage lines. In particular, the cases of deformations of stranded conductors, caused by air expansion or by popped ...

International Nuclear Information System (INIS)

Objective: To explore the feasibility of real-time monitoring exposure dose and image quality by using the data stored in the DICOM image archive of direct digital radiography system. Methods: Model TO. 16 was exposed, the current increased gradually from 0.5 to 125 mAs. The displayed number of model A( diameter 11.1 mm), D (diameter 4.0 mm) and J( diameter 0.7 mm) were recorded, and the detect factors (H_T) was also calculated. Images were sent to workstation before the end of DR examination. An automatic procedure was implemented to extract dose data and exposure parameters from the DICOM header file. Maximum, minimum and 3rd quartile values were preinstalled. Mean values exceeding the threshold trigger alarm signal to guide radiologist to explore the cause. Results: When the current of point A was less than 10 mAs and the current of point D and J were less than 16 mAs, the detect ...

Energy Technology Data Exchange (ETDEWEB)

Threat characterization is a key component in evaluating the threat faced by control systems. Without a thorough understanding of the threat faced by critical infrastructure networks, adequate resources cannot be allocated or directed effectively to the defense of these systems. Traditional methods of threat analysis focus on identifying the capabilities and motivations of a specific attacker, assessing the value the adversary would place on targeted systems, and deploying defenses according to the threat posed by the potential adversary. Too many effective exploits and tools exist and are easily accessible to anyone with access to an Internet connection, minimal technical skills, and a significantly reduced motivational threshold to be able to narrow the field of potential adversaries effectively. Understanding how hackers evaluate new IT security research and incorporate significant new ideas into ...

Energy Technology Data Exchange (ETDEWEB)

The technical development of electric cables in the history of the Berlin electric utilities looks back on more than one century of continuous progress from jute-insulated direct-voltage cables, to 30 kV paper-insulated mass-impregnated cables, 110 kV plastic-insulated cables, 380 kV oil-filled cables, and 380 kV XLPE cables which are increasingly used today. A brief review informs about the major stages of power cable development. (orig.).

Science.gov (United States)

... The combustible cartridge cases currently used by the USArmy in fielded system- are manufactured by two distinct processes. ...

Energy Technology Data Exchange (ETDEWEB)

The RF system for the SuperHILAC injector linac was designed and constructed for minimum system complexity, wide dynamic range, and ease of maintenance. The final amplifier is close coupled to the linac and operates in an efficient semilinear mode, eliminating troublesome transmission lines, modulators, and high level regulators. The system has been operated at over 250 kW, 23 MHz with good regulation. The low level RF electronics are contained in a single chassis adjacent to the RF control computer, which monitors all important operating parameters. A unique 360/sup 0/ phase and amplitude modular is used for precise control and regulation of the accelerating voltage.

Energy Technology Data Exchange (ETDEWEB)

Work over the last few years at the Idaho National Engineering and Environmental Laboratory (INEEL) has included a major focus on applying human performance and human reliability knowledge and methods as an integral element of system design and development. This work has been pursued in programs in a wide variety of technical domains, beginning with nuclear power plant operations. Since the mid-1980`s the laboratory has transferred the methods and tools developed in the nuclear domain to military weapons systems and aircraft, offshore oil and shipping operations, and commercial aviation operations and aircraft design. Through these diverse applications the laboratory has developed an integrated approach and framework for application of human performance analysis, human reliability analysis (HRA), operational data analysis, and simulation studies of human performance to the design and development of complex systems. This ...

Energy Technology Data Exchange (ETDEWEB)

An all solid-state kicker pulser for a proton radiography system has been designed. Multiple solid-state modulators stacked in an inductive-adder configuration are utilized in this kicker pulser design. Each modulator is comprised of multiple metal-oxide-semiconductor field-effect transistors (MOSFETs) which quickly switch the energy storage capacitors across a magnetic induction core. Metglas is used as the core material to minimize loss. Voltage from each modulator is inductively added by a voltage summing stalk. A circuit model of a prototype inductive adder kicker pulser modulator has been developed to predict the performance of the pulser modulator. The modeling results are compared with experimental data.

Energy Technology Data Exchange (ETDEWEB)

The development and installation, by Hydro-Quebec, of a computerized pressure monitoring and control system on its fluid-filled high voltage underground cable network in Montreal, was described. The average age of these underground fluid-filled cables is more than 30 years and the cost to replace the circuits is estimated to be 230 million dollars. It is, therefore, crucial to maintain at all times and under all operating conditions a positive oil pressure in order to maintain the dielectric strength of paper insulation, and to prevent air and moisture from entering the cables and accessories. The monitoring and control system is reliable, flexible, user friendly and easy to upgrade. It reduces intervention time on the cables and ensures the protection of the cable network by remotely operating valves to connect oil reserve banks and by providing efficient maintenance management tools. 1 ref., 1 tab., 4 figs.

International Nuclear Information System (INIS)

One of the design targets for the ITER Tokamak Exhaust Processing system is not to lose more than 10"-"5 g h"-"1 into the Normal Vent Detritiation System of the Tritium Plant. The plasma exhaust gas, therefore, needs to be processed in a way that an overall tritium removal efficiency of about 10"8 is reached. Such a high decontamination factor can only be achieved by multistage processes. The third step of the three step CAPER process developed at the TLK is based on a so-called permeator catalyst (PERMCAT) reactor, a direct combination of a Pd/Ag permeation membrane and a catalyst bed. The PERMCAT principle is based on isotopic swamping in a counter current mode. Previous tritium experiments employing laboratory scale PERMCAT reactors have revealed decontamination factors as high as 10"5 for the third CAPER step. First tritium tests with a technical scale PERMCAT reactor led to similar decontamination ...

Energy Technology Data Exchange (ETDEWEB)

The objectives of the project were (i) to develop a combination iron oxide production and carbon sequestration plant that will use serpentine ores as the source of iron and the extraction tailings as the storage element for CO2 disposal, (ii) the identification of locations within the US where this process may be implemented and (iii) to create a standardized process to characterize the serpentine deposits in terms of carbon disposal capacity and iron and steel production capacity. The first objective was not accomplished. The research failed to identify a technique to accelerate direct aqueous mineral carbonation, the limiting step in the integration of steel production and carbon sequestration. Objective (ii) was accomplished. It was found that the sequestration potential of the ultramafic resource surfaces in the US and Puerto Rico is approximately 4,647 Gt of CO2 or over 500 years of current US production of CO2. Lastly, a computer model ...

British Library Electronic Table of Contents (United Kingdom)

This paper investigates the effects of the electric current pulse (ECP) on the interface stability of Al-4.5% Cu alloy during the directional solidification. Experimental results show both the cellular spacing and the mushy zone depth decrease with increasing current density, moreover, the solid-liquid interface morphology transforms from dendritic to cellular or even planar interface. The secondary dendrites are suppressed due to the homogeneous distribution of the solute and the increase of temperature gradient originated from ECP. The decrease of the cellular spacing results from branching of the cellular tip caused by Joule heat of the current exerting on cellular tip.

CERN Document Server

New non-stationary non-contracted form of the erosive radially-slotted discharge as a thin round sheet with the current of the azimuth direction have been discovered, its existence beings stipulated by a radial transport-wave fluxes. Characteristic features of this discharge is self-confinement of the discharge current magnitude, corresponding decrease of the current pulse duration and occurrence of an energy and substance ejection with rather unusual properties. Measurements of kinetics of the discharge current, the plasma radiation intensity and an electrical probe signal, as well as the transmission electron microscope investigations of characteristic aerodisperse aggregates arising the erosive phase, have been carried out. The probe signal duration was about 10 times greater than that of the current; its kinetics was complicated suggesting existence in the ...

Energy Technology Data Exchange (ETDEWEB)

This paper presents a real-time wavelet-Fuzzy combined approach for digital relaying. The algorithm for fault classification employs wavelet multi resolution analysis (MRA) to overcome the difficulties associated with conventional voltage and current based measurements due to effect of factors such as fault inception angle, fault impedance and fault distance. The proposed algorithm for fault location, different from conventional algorithms that are based on deterministic computations on a well-defined model to be protected, employs wavelet transform together with fuzzy logic. The wavelet transform captures the dynamic characteristics of the non-stationary transient fault signals using wavelet MRA coefficients. The fuzzy logic is employed to incorporate expert evaluation through fuzzy inference system (FIS) so as to extract important features from wavelet MRA coefficients for obtaining coherent conclusions regarding fault ...

Science.gov (United States)

Integration of Eddy Current probes with MAUS scanning system has been demonstrated to produce scan rates of 36 sqft/hour. System will be designed to ...

Science.gov (United States)

Near-ideal Schottky barrier contacts to n-type Al0.22Ga0.78N have been developed by a two-step surface treatment technique. Plasma etching of the AlxGa1-xN surface prior to Schottky metal deposition, combined with sequential chemical treatment of the etched surface, holds promise for developing high quality low-leakage Schottky contacts for low noise applications and for recessed gate high electron mobility transistors. In this work, the effect of postetch chemical treatment of the n-type Al0.22Ga0.78N surface on the performance of the Ni/Au based Schottky contact has been investigated. Three different types of chemical treatment: viz, reactive ion etching, reactive ion etching plus dipping in hot aqua regia, and reactive ion etching plus dipping in hot KOH, are studied. Detailed current-voltage studies of three different surface treated diodes and a comparison with as-deposited diodes reveal significant improvement in the diode characteristics. The latter surface ...

International Nuclear Information System (INIS)

Full text: The principal nuclear design tools available to the shielding designer include diffusion approximation, transport theory, and Monte Carlo techniques. Full transport theory or Monte Carlo methods are routinely used for shielding analyses, where penetration investigations are more sensitive to directional aspects. However, the aim of this paper is to illustrate the coupled neutron-gamma Albedo method particularly as applied to problems of shielding analysis. The multigroup Albedo method is applied to coupled neutron-gamma radiations considering 'n' neutron energy groups and 'g' gamma energy groups to estimate the probabilities of transmission through, absorption in, and reflection from shieldings composed by multiple material layers, 'm' slabs, in which no fission occurs. In this study, these energy groups were selected in order to minimize upscattering effects of the radiation from lower energy groups to higher energy groups. However, neutrons of all ...

UK PubMed Central (United Kingdom)

The presence of highly heat-resistant spores of Bacillus sporothermodurans in ultrahigh-temperature or sterilized consumer milk has emerged as an important item in the dairy industry....Full Text Available

International Nuclear Information System (INIS)

Based on a detailed analysis of the inter-relationship in the current, voltage, electromagnetic torque and ratio of the difference between the speed of rotor and the speed of rotary magnetic field to the later in the motor, the root cause was point out, which leads to the protection fuses' failure of the motor in the starting stage, which drives the turbine-generator set to rotate at low speed before its startup. Two solutions to avoid the situation are proposed, too. (authors)

Energy Technology Data Exchange (ETDEWEB)

In this paper, an approximate curve fitting method for photovoltaic modules is presented. The operation is based on solving a simple solar cell electrical model by a microcontroller in real time. Only four voltage and current coordinates are needed to obtain the solar module parameters and set its operation at maximum power in any conditions of illumination and temperature. Despite its simplicity, this method is suitable for low cost real time applications, as control loop reference generator in photovoltaic maximum power point circuits. The theory that supports the estimator together with simulations and experimental results are presented. (author)

UK PubMed Central (United Kingdom)

Though central to our understanding of how roots perform their vital function of scavenging water and solutes from the soil, no direct genetic evidence currently exists to support the foundational model...Full Text Available

UK PubMed Central (United Kingdom)

Opioids have been regarded for millennia as among the most effective drugs for the treatment of pain. Their use in the management of acute severe pain and chronic pain related to advanced medical...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

A compact cesium deposition system was used for direct deposition of cesium atoms and ions onto the inner surface of the 1/3 scale Hydrogen Negative Ion Source for the LHD-NBI system. A small, well defined amount of cesium deposition in the range of 3-200 mg was tested. Negative ion extraction and acceleration were carried out both in the pure hydrogen operation mode and in the cesium mode. Single Cs deposition of 3-30 mg to the plasma chamber have produced temporary 2-5 times increases of H-yield, but the yield was decreased within several discharge pulses to the previous steady-state value. Two consecutive 30 mg depositions done within a 3-5 hours/60 shot interval, produced a similar temporary increase of H-beam, but reached a larger H-yield steady-state value. Deposition of larger 0.1-0.2 g Cs portions with a 20-120 hours/150-270 shot interval improved the H-yield for a long (2-5 days) period of operation. ...

Science.gov (United States)

...2010-10-01 false Department of Energy Directives. 970.0470 Section...Acquisition Regulations System DEPARTMENT OF ENERGY AGENCY SUPPLEMENTARY REGULATIONS ...Matters 970.0470 Department of Energy...

International Nuclear Information System (INIS)

The mixed structure of a nuclear reactor building is composed of SC-columns, S-beams, S-joints and PCa-panels. Following the last report (Part 7)[1], the main test results of the mixed structure, that is, the deformation mode, strain distribution and shear strength, are described. The S-joints using ultrahigh strength materials had no buckling nor shear slipping. The proposed mixed structure resisted the external horizontal forces under integrated uniformity among SC-columns, S-joints and PCa-panels. It could be confirmed that the mixed structure can be established. (author)

Energy Technology Data Exchange (ETDEWEB)

An investigation was conducted into alternative techniques for zinc and electrolyte regeneration and reuse in the refuelable zinc/air battery that was developed by LLNL and previously tested on a moving electric bus using cut wire. Mossy zinc was electrodeposited onto a bipolar array of inclined Ni plates with an energy consumption of 1.8 kWh/kg. Using a H{sub 2}-depolarized anode, zinc was deposited at 0.6 V (0.8 kA/m{sup 2}); the open circuit voltage was 0.45 V. Three types of fuel pellets were tested and compared with results for 0.75 mm cut wire: spheres produced in a spouted bed (UCB); coarse powder produced by gas-atomization (Noranda); and irregular pellets produced by chopping 1-mm plates of compacted zinc fines (Eagle-Picher, Inc.). All three types transported within the cell. The coarse powder fed continuously from hopper to cell, as did the compacted pellets (< 0.83 mm). Large particles (> 0.83 mm; Eagle-Picher and UCB) failed to feed from ...

International Nuclear Information System (INIS)

Scanning ion microscopy with polarization analysis (SIMPA) is used to study the spin-resolved surface magnetic structure of nano-sized magnetic systems. SIMPA is utilized for in situ topographic and spin-resolved magnetic domain imaging as well as for focused ion beam (FIB) etching of desired structures in magnetic or non-magnetic systems. Ultra-thin Co films are deposited on surfaces of Si(1 0 0) substrates, and ultra-thin, tri-layered, bct Fe(1 0 0)/Mn/bct Fe(1 0 0) wedged magnetic structures are deposited on fcc Pd(1 0 0) substrates. SIMPA experiments clearly show that ion-induced electrons emitted from magnetic surfaces exhibit non-zero electron spin polarization (ESP), whereas electrons emitted from non-magnetic surfaces such as Si and Pd exhibit zero ESP, which can be used to calibrate sputtering rates in situ. We report on new, spin-resolved magnetic microstructures, such as magnetic 'C' states and magnetic vortices, found at surfaces of ...

Energy Technology Data Exchange (ETDEWEB)

The Conawapa-Winnipeg Power Transmission Complex includes five interrelated transmission and conversion facilities. This booklet describes work done on the upgrade of the southern receiver system, one component of the complex. The southern receiver system is composed of a network of high voltage transmission lines and station facilities. The booklet includes a description of the upgrade, the project setting, short and long-term effects and impact management, and the next steps to be taken in the process, including the regulatory process and public consultation.

British Library Electronic Table of Contents (United Kingdom)

This study correlates the post start cell performance and impedance with the cold start process in the subzero environment. The sequential failed cold starts are deliberately conducted as well as the start at small current density. Here the failed cold start means the cell voltage drops to or below zero within very short time during the start process. It is found that there are reversible performance losses for the sequential failed cold starts, while not obvious degradation and no recovery happen for the start at small current density. Using the thin film and agglomerate model, it is confirmed that this is due to the water blocking effect. Comparing the results from different start processes, a model with respect to the shifting of reactive region within the catalyst layer is applied to e...

British Library Electronic Table of Contents (United Kingdom)

Aim:To examine the electrophysiological effects of sophocarpine on action potentials (AP) and ionic currents of cardiac myocytes and to compare some of these effects with those of amiodarone.Methods:Langendorff perfusion set-up was used in isolated guinea pig heart, and responses to sophocarpine were monitored using electrocardiograph. Conventional microelectrode, voltage clamp technique and perforated patch were employed to record fast response AP (fAP), slow response AP (sAP) and ionic currents in guinea pig papillary muscle or rabbit sinus node cells.Results:Tachyarrhythmia produced by isoprenaline (15 ?mol/L) could be reversed by sophocarpine (300 ?mol/L). Sophocarpine (10 ?mol/L) decreased the amplitude by 4.0%, maximal depolarization velocity (Vmax) of the fAP by 24.4%...