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Sample records for ac line voltage

  1. Increased deposition of polychlorinated biphenyls (PCBs) under an AC high-voltage power line

    NASA Astrophysics Data System (ADS)

    Öberg, Tomas; Peltola, Pasi

    2009-12-01

    There is considerable public concern regarding the potential risks to health of electromagnetic fields in general and high-voltage power lines in particular. As epidemiological findings are not supported by a clearly defined mechanism of direct magnetic field interactions with the human body, potential indirect effects are of interest. It has been suggested that an increased exposure to chemical pollutants could occur near high-voltage power lines due to formation and deposition of charged aerosols. The current study reports empirical evidence that seems to support this hypothesis. The deposition of 18 congeners of polychlorinated biphenyls (PCBs) was studied by collecting samples of pine needles under a 400 kV AC power line and at reference sites in the vicinity. Compared to the reference sites, the average deposition of PCB congeners under the power line was almost double. This difference between the two groups of samples was statistically significant. While it is premature to draw any conclusions regarding the human exposure near high-voltage power lines, the issue deserves attention and further investigations.

  2. Basic concepts of induced AC voltages on pipelines

    SciTech Connect

    Kirkpatrick, E.L.

    1995-07-01

    The phenomena of induced AC on pipelines sharing common rights-of-way with overhead high-voltage electrical transmission power lines is discussed. Basic concepts and techniques for personnel safety and some pipeline protective measures are reviewed.

  3. An automatic AC/DC thermal voltage converter and AC voltage calibration system

    NASA Astrophysics Data System (ADS)

    Lentner, K. J.; Flach, D. R.; Bell, B. A.

    1985-10-01

    An automatic ac/dc difference calibration system is described which uses direct measurement of thermoelement emfs. In addition to ac/dc difference testing, the system can be used to measure some important characteristics of thermoelements, as well as to calibrate ac voltage calibrators and precision voltmeters. The system operates over a frquency range from 20 Hz to 100 kHz, covering the voltage range from 0.5 V to 1 kv. For all voltages the total measurement uncertainties expected (including the uncertainty of the specific reference thermal converters used) were 50 parts per million (ppm) at frequencies from 20 Hz to 20 kHz, inclusive, and 100 ppm at higher frequencies up to 100 kHz.

  4. Automatic ac/dc thermal voltage converter and ac voltage calibration system

    NASA Astrophysics Data System (ADS)

    Lentner, K. J.; Flach, D. R.; Bell, B. A.

    1984-11-01

    An automatic ac/dc difference calibration system is described which uses direct measurement of thermoelement emfs. In addition to ac/dc difference testing, the system can be used to measure some important characteristics of thermoelements, as well as to calibrate ac voltage calibrators and precision voltmeters. The system operates over a frequency range from 20 Hz to 100 kHz, covering the voltage range from 0.5 V to 1 kv. For all voltages the total measurement uncertainties expected (including the uncertainty of the specific reference thermal converters used) were 50 parts per million (ppm) at frequencies from 20 Hz to 20 kHz, inclusive, and 100 ppm at higher frequencies up to 100 kHz.

  5. An Annotated Bibliography of High-Voltage Direct-Current Transmission and Flexible AC Transmission (FACTS) Devices, 1991-1993.

    SciTech Connect

    Litzenberger, Wayne; Lava, Val

    1994-08-01

    References are contained for HVDC systems, converter stations and components, overhead transmission lines, cable transmission, system design and operations, simulation of high voltage direct current systems, high-voltage direct current installations, and flexible AC transmission system (FACTS).

  6. Transient AC voltage related phenomena for HVDC schemes connected to weak AC systems

    SciTech Connect

    Pilotto, L.A.S.; Szechtman, M. ); Hammad, A.E. )

    1992-07-01

    In this paper a didactic explanation of voltage stability associated phenomena at HVDC terminals is presented. Conditions leading to ac voltage collapse problems are identified. A mechanism that excites control-induced voltage oscillations is shown. The voltage stability factor is used for obtaining the maximum power limits of ac/dc systems operating with different control strategies. Correlation to Pd {times} Id curves is given. Solutions for eliminating the risks of voltage collapse and for avoiding control-induced oscillations are discussed. The results are supported by detailed digital simulations of a weak ac/dc system using EMTP.

  7. A Generalised Fault Protection Structure Proposed for Uni-grounded Low-Voltage AC Microgrids

    NASA Astrophysics Data System (ADS)

    Bui, Duong Minh; Chen, Shi-Lin; Lien, Keng-Yu; Jiang, Jheng-Lun

    2016-04-01

    This paper presents three main configurations of uni-grounded low-voltage AC microgrids. Transient situations of a uni-grounded low-voltage (LV) AC microgrid (MG) are simulated through various fault tests and operation transition tests between grid-connected and islanded modes. Based on transient simulation results, available fault protection methods are proposed for main and back-up protection of a uni-grounded AC microgrid. In addition, concept of a generalised fault protection structure of uni-grounded LVAC MGs is mentioned in the paper. As a result, main contributions of the paper are: (i) definition of different uni-grounded LVAC MG configurations; (ii) analysing transient responses of a uni-grounded LVAC microgrid through line-to-line faults, line-to-ground faults, three-phase faults and a microgrid operation transition test, (iii) proposing available fault protection methods for uni-grounded microgrids, such as: non-directional or directional overcurrent protection, under/over voltage protection, differential current protection, voltage-restrained overcurrent protection, and other fault protection principles not based on phase currents and voltages (e.g. total harmonic distortion detection of currents and voltages, using sequence components of current and voltage, 3I0 or 3V0 components), and (iv) developing a generalised fault protection structure with six individual protection zones to be suitable for different uni-grounded AC MG configurations.

  8. Effect of low voltage AC fields on cardiovascular implants.

    PubMed

    Kothandaraman, Anjana; Anson, Tony; Reynolds, Alan

    2015-01-01

    Coronary Artery Stents have been the preferred form of treatment for vascular occlusive disease, due to the minimally invasive surgical procedure, post-operative recovery time and cost, when compared to open coronary bypass surgery. The cellular response upon applying an AC electric field to type 316LM Stainless Steel stent mimics was investigated in this paper. The highest RBC adhesion was observed at voltages higher than 88 mV and lower than 74 mV. Their unique alignment along the lines of fracture on the stent surface at 88 mV was a phenomenon caused by an increase in electrical conductivity in these regions. Being able to control RBC adhesion may have various clinical implications such as inhibition of thrombus formation, and provide a basis to analyse whether electric fields may be applied to cancer therapy as well.

  9. Advanced Sensors for Accurate, Broadband AC Voltage Metrology

    NASA Astrophysics Data System (ADS)

    Lipe, Thomas E.; Kinard, Joseph R.; Novotny, Donald B.; Sims, June E.

    2013-06-01

    We report on advances in ac voltage metrology made possible by a new generation of Multijunction Thermal Converters (MJTCs). Although intended for use primarily in high-frequency (1 MHz to 100 MHz) metrology, their exceptional low-frequency qualities, combined with a large dynamic range, makes these MJTCs excellent devices for the frequency range 10 Hz to 100 MHz at voltages from 1 V to 20 V, depending on the design. We anticipate that these devices will form the future basis for ac voltage metrology at the National Institute of Standards and Technology (NIST).

  10. Fast recovery, high voltage silicon diodes for AC motor controllers

    NASA Technical Reports Server (NTRS)

    Balodis, V.; Berman, A. H.; Gaugh, C.

    1982-01-01

    The fabrication and characterization of a high voltage, high current, fast recovery silicon diode for use in AC motor controllers, originally developed for NASA for use in avionics power supplies, is presented. The diode utilizes a positive bevel PIN mesa structure with glass passivation and has the following characteristics: peak inverse voltage - 1200 volts, forward voltage at 50 amperes - 1.5 volts, reverse recovery time of 200 nanoseconds. Characterization data for the diode, included in a table, show agreement with design concepts developed for power diodes. Circuit diagrams of the diode are also given.

  11. Diagnostic of water trees using DC and AC voltages

    SciTech Connect

    Romero, P.; Puerta, J.

    1996-12-31

    Electric tools for non-destructive water tree diagnostic in XLPE medium voltage cables, by means of DC and AC voltages are presented. The DC method is related to the determination of a non-linear dependence of the polarization current on the applied DC step voltage, in contrast to a linear dependence found in non-water tree-damaged cables. In both cases the current follows the Curie-von Schweidler empirical law, I(t) = I{sub 0}t{sup {minus}n}. The AC method is based on the measurement of the dispersion relation of both the loss factor and the capacitance in the low and very low frequency ranges by means of the Fourier Transform techniques. The devised measuring instrumentation is presented.

  12. Strongly nonlinear dynamics of electrolytes in large ac voltages.

    PubMed

    Højgaard Olesen, Laurits; Bazant, Martin Z; Bruus, Henrik

    2010-07-01

    We study the response of a model microelectrochemical cell to a large ac voltage of frequency comparable to the inverse cell relaxation time. To bring out the basic physics, we consider the simplest possible model of a symmetric binary electrolyte confined between parallel-plate blocking electrodes, ignoring any transverse instability or fluid flow. We analyze the resulting one-dimensional problem by matched asymptotic expansions in the limit of thin double layers and extend previous work into the strongly nonlinear regime, which is characterized by two features--significant salt depletion in the electrolyte near the electrodes and, at very large voltage, the breakdown of the quasiequilibrium structure of the double layers. The former leads to the prediction of "ac capacitive desalination" since there is a time-averaged transfer of salt from the bulk to the double layers, via oscillating diffusion layers. The latter is associated with transient diffusion limitation, which drives the formation and collapse of space-charge layers, even in the absence of any net Faradaic current through the cell. We also predict that steric effects of finite ion sizes (going beyond dilute-solution theory) act to suppress the strongly nonlinear regime in the limit of concentrated electrolytes, ionic liquids, and molten salts. Beyond the model problem, our reduced equations for thin double layers, based on uniformly valid matched asymptotic expansions, provide a useful mathematical framework to describe additional nonlinear responses to large ac voltages, such as Faradaic reactions, electro-osmotic instabilities, and induced-charge electrokinetic phenomena.

  13. High Voltage Lines: Hazard at a Distance.

    ERIC Educational Resources Information Center

    Marino, Andrew A.; Becker, Robert O.

    1978-01-01

    It appears that a variety of biological organisms, including man, are sensitive to both long and short-term exposure to the extra low frequency electric and magnetic fields produced by high voltage lines. (BB)

  14. Moderately nonlinear diffuse-charge dynamics under an ac voltage.

    PubMed

    Stout, Robert F; Khair, Aditya S

    2015-09-01

    The response of a symmetric binary electrolyte between two parallel, blocking electrodes to a moderate amplitude ac voltage is quantified. The diffuse charge dynamics are modeled via the Poisson-Nernst-Planck equations for a dilute solution of point-like ions. The solution to these equations is expressed as a Fourier series with a voltage perturbation expansion for arbitrary Debye layer thickness and ac frequency. Here, the perturbation expansion in voltage proceeds in powers of V_{o}/(k_{B}T/e), where V_{o} is the amplitude of the driving voltage and k_{B}T/e is the thermal voltage with k_{B} as Boltzmann's constant, T as the temperature, and e as the fundamental charge. We show that the response of the electrolyte remains essentially linear in voltage amplitude at frequencies greater than the RC frequency of Debye layer charging, D/λ_{D}L, where D is the ion diffusivity, λ_{D} is the Debye layer thickness, and L is half the cell width. In contrast, nonlinear response is predicted at frequencies below the RC frequency. We find that the ion densities exhibit symmetric deviations from the (uniform) equilibrium density at even orders of the voltage amplitude. This leads to the voltage dependence of the current in the external circuit arising from the odd orders of voltage. For instance, the first nonlinear contribution to the current is O(V_{o}^{3}) which contains the expected third harmonic but also a component oscillating at the applied frequency. We use this to compute a generalized impedance for moderate voltages, the first nonlinear contribution to which is quadratic in V_{o}. This contribution predicts a decrease in the imaginary part of the impedance at low frequency, which is due to the increase in Debye layer capacitance with increasing V_{o}. In contrast, the real part of the impedance increases at low frequency, due to adsorption of neutral salt from the bulk to the Debye layer. PMID:26465471

  15. Strongly nonlinear dynamics of electrolytes in large ac voltages

    NASA Astrophysics Data System (ADS)

    Højgaard Olesen, Laurits; Bazant, Martin Z.; Bruus, Henrik

    2010-07-01

    We study the response of a model microelectrochemical cell to a large ac voltage of frequency comparable to the inverse cell relaxation time. To bring out the basic physics, we consider the simplest possible model of a symmetric binary electrolyte confined between parallel-plate blocking electrodes, ignoring any transverse instability or fluid flow. We analyze the resulting one-dimensional problem by matched asymptotic expansions in the limit of thin double layers and extend previous work into the strongly nonlinear regime, which is characterized by two features—significant salt depletion in the electrolyte near the electrodes and, at very large voltage, the breakdown of the quasiequilibrium structure of the double layers. The former leads to the prediction of “ac capacitive desalination” since there is a time-averaged transfer of salt from the bulk to the double layers, via oscillating diffusion layers. The latter is associated with transient diffusion limitation, which drives the formation and collapse of space-charge layers, even in the absence of any net Faradaic current through the cell. We also predict that steric effects of finite ion sizes (going beyond dilute-solution theory) act to suppress the strongly nonlinear regime in the limit of concentrated electrolytes, ionic liquids, and molten salts. Beyond the model problem, our reduced equations for thin double layers, based on uniformly valid matched asymptotic expansions, provide a useful mathematical framework to describe additional nonlinear responses to large ac voltages, such as Faradaic reactions, electro-osmotic instabilities, and induced-charge electrokinetic phenomena.

  16. Nonlinear oscillations in an electrolyte solution under ac voltage.

    PubMed

    Schnitzer, Ory; Yariv, Ehud

    2014-03-01

    The response of an electrolyte solution bounded between two blocking electrodes subjected to an ac voltage is considered. We focus on the pertinent thin-double-layer limit, where this response is governed by a reduced dynamic model [L. Højgaard Olesen, M. Z. Bazant, and H. Bruus, Phys. Rev. E 82, 011501 (2010)]. During a transient stage, the system is nonlinearly entrained towards periodic oscillations of the same frequency as that of the applied voltage. Employing a strained-coordinate perturbation scheme, valid for moderately large values of the applied voltage amplitude V, we obtain a closed-form asymptotic approximation for the periodic orbit which is in remarkable agreement with numerical computations. The analysis elucidates the nonlinear characteristics of the system, including a slow (logarithmic) growth of the zeta-potential amplitude with V and a phase straining scaling as V-1lnV. In addition, an asymptotic current-voltage relation is provided, capturing the numerically observed rapid temporal variations in the electric current. PMID:24730837

  17. Electric power high-voltage transmission lines: Design options, cost, and electric and magnetic field levels

    SciTech Connect

    Stoffel, J.B.; Pentecost, E.D.; Roman, R.D.; Traczyk, P.A.

    1994-11-01

    This report provides background information about (1) the electric and magnetic fields (EMFs) of high-voltage transmission lines at typical voltages and line configurations and (2) typical transmission line costs to assist on alternatives in environmental documents. EMF strengths at 0 {+-} 200 ft from centerline were calculated for ac overhead lines, and for 345 and 230-kV ac underground line and for a {+-}450-kV dc overhead line. Compacting and height sensitivity factors were computed for the variation in EMFs when line conductors are moved closer or raised. Estimated costs for the lines are presented and discussed so that the impact of using alternative strategies for reducing EMF strengths and the implications of implementing the strategies can be better appreciated.

  18. A system for tranmitting low frequency analog signals over ac power lines

    DOEpatents

    Baker, S.P.; Durall, R.L.; Haynes, H.D.

    1987-07-30

    A system for transmitting low frequency analog signals over ac power lines using FM modulation. A low frequency analog signal to be transmitted is first applied to a voltage-to-frequency converter where it is converted to a signal whose frequency varies in proportion to the analog signal amplitude. This signal is then used to modulate the carrier frequency of an FM transmitter coupled to an ac power line. The modulation signal frequency range is selected to be within the response band of the FM transmitter. The FM modulated carrier signal is received by an FM receiver coupled to the ac power line, demodulated and the demodulated signal frequency is converted by a frequency-to-voltage converter back to the form of the original low frequency analog input signal. 4 figs.

  19. System for transmitting low frequency analog signals over AC power lines

    DOEpatents

    Baker, Steven P.; Durall, Robert L.; Haynes, Howard D.

    1989-09-05

    A system for transmitting low frequency analog signals over AC power lines using FM modulation. A low frequency analog signal to be transmitted is first applied to a voltage-to-frequency converter where it is converted to a signal whose frequency varies in proportion to the analog signal amplitude. This signal is then used to modulate the carrier frequency of an FM transmitter coupled to an AC power line. The modulation signal frequency range in selected to be within the response band of the FM transmitter. The FM modulated carrier signal is received by an FM receiver coupled to the AC power line, demodulated and the demodulated signal frequency is converted by a frequency-to-voltage converter back to the form of the original low frequency analog input signal.

  20. System for transmitting low frequency analog signals over AC power lines

    DOEpatents

    Baker, Steven P.; Durall, Robert L.; Haynes, Howard D.

    1989-01-01

    A system for transmitting low frequency analog signals over AC power lines using FM modulation. A low frequency analog signal to be transmitted is first applied to a voltage-to-frequency converter where it is converted to a signal whose frequency varies in proportion to the analog signal amplitude. This signal is then used to modulate the carrier frequency of an FM transmitter coupled to an AC power line. The modulation signal frequency range in selected to be within the response band of the FM transmitter. The FM modulated carrier signal is received by an FM receiver coupled to the AC power line, demodulated and the demodulated signal frequency is converted by a frequency-to-voltage converter back to the form of the original low frequency analog input signal.

  1. Voltage source ac-to-dc converters for high-power transmitters

    NASA Technical Reports Server (NTRS)

    Cormier, R.

    1990-01-01

    This work was done to optimize the design of the components used for the beam power supply, which is a component of the transmitters in the Deep Space Network (DSN). The major findings are: (1) the difference in regulation between a six-pulse and a twelve-pulse converter is at most 7 percent worse for the twelve-pulse converter; (2) the commutation overlap angle of a current source converter equals that of a voltage source converter with continuous line currents; (3) the sources of uncharacteristic harmonics are identified with SPICE simulation; (4) the use of an imperfect phase-shifting transformer for the twelve-pulse converter generates a harmonic at six times the line frequency; and (5) the assumptions usually made in analyzing converters can be relaxed with SPICE simulation. The results demonstrate the suitability of using SPICE simulation to obtain detailed performance predictions of ac-to-dc converters.

  2. AC and lightning performance of fiberglass crossarms aged in 115 kV transmission line

    SciTech Connect

    Grzybowski, S. . Dept. of Electrical and Computer Engineering); Jenkins, E.B. . Generation and Transmission Group)

    1993-10-01

    This paper presents the results of an investigation of the electrical performance of 115 kV transmission line fiberglass cross-arm used by Mississippi Power and Light Company. A transmission line fiberglass crossarm removed from service and companion cross-arms outdoors but not in service were examined. The evaluation of electrical performance was based on flashover voltage value at AC voltage and standard lightning impulses as well as under dry and wet conditions. The tests were performed in the Mississippi State University High Voltage Laboratory. The obtained flashover voltages show no large differences in electrical strength of fiberglass crossarms removed from service and those stored outdoors. The Added CFO voltage by fiberglass crossarm to the porcelain suspension insulators is presented versus the length of the fiberglass crossarm for dry and wet conditions.

  3. Derivation of Instantaneous Wye and Zero-Phase Sequence Voltages from Line-Line Voltages in Unbalanced 3-Phase 3-Wire Systems and Application of This Method to 3-Phase PWM Converter Control

    NASA Astrophysics Data System (ADS)

    Yuzurihara, Itsuo; Kawamura, Atsuo

    In general, voltage imbalances in 3-phase AC power systems are inevitable. 3-Phase PWM (Pulse Width Modulation) converter used in 3-wire systems are generally designed for use under limited imbalances of input voltages, and problems such as input current distortion, deterioration of output properties, degradation of efficiency and failure may occur in some cases. These problems cause severe damages to industries in some cases, for example, semiconductor production machines: SEMI defined “SEMI F47-0200” and “SEMI F47-0706” standards that have to be satisfied to realize voltage sag immunity. In order to compensate the remained problems due to the unbalanced input voltages, particular storage devices are designed additionally for conventional converters. This paper proposes that the determination of both the instantaneous zero-phase sequence voltage and wye voltages is essential for 3-phase PWM converter control used for a 3-wire system to keep its output rated under occasional or long-term voltage imbalances in an AC system. This paper also describes a general new method to derive the components of the voltages of instantaneous wye and zero-phase sequence voltage from line-line voltages of a 3-wire system. This paper also describes a method to apply the voltages to control the converter. The results obtained on implementation verify that this new converter keeps its output rated under unbalanced conditions wider than those defined by SEMIs without particular storage devices as far as the AC voltages are remained live.

  4. Phase-sensitive detection of both inductive and non-inductive ac voltages in ferromagnetic resonance

    NASA Astrophysics Data System (ADS)

    Weiler, Mathias; Shaw, Justin M.; Nembach, Hans T.; Schoen, Martin A.; Boone, Carl T.; Silva, Thomas J.

    2014-03-01

    Spin pumping causes significant damping in ultrathin ferromagnetic/normal metal (NM) multilayers via spin-current generation of both dc and ac character in the NM system. While the nonlinear dc component has been investigated in detail by utilization of the inverse spin Hall effect (iSHE) in NMs, much less is known about the linear ac component that is presumably much larger in the small-excitation limit. We measured generated ac voltages in a wide variety of Permalloy/NM multilayers via vector-network-analyzer ferromagnetic resonance. We employ a custom, impedance-matched, broadband microwave coupler that features a ferromagnetic thin film reference resonator to accurately compare ac voltage amplitudes and phases between varieties of multilayers. By use of the fact that inductive and ac iSHE signals are phase-shifted by π/2, we find that inductive signals are major contributors in all investigated samples. It is only by comparison of the phase and amplitude of the recorded ac voltages between multiple samples that we can extract the non-inductive contributions due to spin-currents. Voltages due to the ac iSHE in Permalloy(10nm)/platinum(5nm) bilayers are weaker than inductive signals, in agreement with calculations based upon recent theoretical predictions. M.W. acknowledges financial support by the German Academic Exchange service (DAAD).

  5. Ac irreversibility line of bismuth-based high temperature superconductors

    SciTech Connect

    Mehdaoui, A.; Beille, J.; Berling, D.; Loegel, B.; Noudem, J.G.; Tournier, R.

    1997-09-01

    We discuss the magnetic properties of lead doped Bi-2223 bulk samples obtained through combined magnetic melt texturing and hot pressing (MMTHP). The ac complex susceptibility measurements are achieved over a broad ac field range (1 Oe{lt}h{sub ac}{lt}100 Oe) and show highly anisotropic properties. The intergranular coupling is improved in the direction perpendicular to the applied stress and magnetic field direction, and an intragranular loss peak is observed for the first time. A comparison is made with other bismuth-based compounds and it is shown that the MMTHP process shifts the ac irreversibility line (ac IL) toward higher fields. It is also shown that all the ac IL{close_quote}s for quasi 2D bismuth-based compounds show a nearly quadratic temperature dependence and deviate therefore strongly from the linear behavior observed in quasi 3D compounds and expected from a critical state model.{copyright} {ital 1997 Materials Research Society.}

  6. New internal multi-range resistors for ac voltage calibration by using TVC

    NASA Astrophysics Data System (ADS)

    Ali, Rasha S. M.

    2015-10-01

    Accurate calibration of ac voltages up to 1000 V by using thermal converters requires range resistors connected in series with the converter. The combination of a thermal converter and range resistor is known as the thermal voltage converter. In this paper, multi-range internal range resistors are designed and implemented in the National Institute for Standards (NIS), Egypt to cover the ac voltage ranges from 10 V to 750 V. The range resistor values are 2 kΩ, 10 kΩ, 20 kΩ, 40 kΩ, 100 kΩ, and 150 kΩ to cover the voltage ranges 10 V, 50 V, 100 V, 200 V, 500 V, and 750 V, respectively. The six range resistors are mounted in series with a single-junction thermo-element in the same box to provide a new thermal voltage converter. The required range resistor is selected by using a six-pin selector switch. Each resistor is connected to a selector pin. The new thermal voltage converter ranges are automatically calibrated against other standard thermal voltage converters at different frequencies by using a LabVIEW program to determine their ac-dc transfer difference at each range. The expanded uncertainties are estimated according to the GUM for all ranges at different frequencies. The performance of the new thermal voltage converter is also evaluated by comparing its ac-dc differences and its accuracy in measuring the ac voltage at different frequencies with a traditional thermal voltage converter.

  7. Living and Working Safely Around High-Voltage Power Lines.

    SciTech Connect

    United States. Bonneville Power Administration.

    2001-06-01

    High-voltage transmission lines can be just as safe as the electrical wiring in the homes--or just as dangerous. The crucial factor is ourselves: they must learn to behave safely around them. This booklet is a basic safety guide for those who live and work around power lines. It deals primarily with nuisance shocks due to induced voltages, and with potential electric shock hazards from contact with high-voltage lines. References on possible long-term biological effects of transmission lines are shown. In preparing this booklet, the Bonneville Power Administration has drawn on more than 50 years of experience with high-voltage transmission. BPA operates one of the world`s largest networks of long-distance, high-voltage lines. This system has more than 400 substations and about 15,000 miles of transmission lines, almost 4,400 miles of which are operated at 500,000 volts.

  8. Switch contact device for interrupting high current, high voltage, AC and DC circuits

    DOEpatents

    Via, Lester C.; Witherspoon, F. Douglas; Ryan, John M.

    2005-01-04

    A high voltage switch contact structure capable of interrupting high voltage, high current AC and DC circuits. The contact structure confines the arc created when contacts open to the thin area between two insulating surfaces in intimate contact. This forces the arc into the shape of a thin sheet which loses heat energy far more rapidly than an arc column having a circular cross-section. These high heat losses require a dramatic increase in the voltage required to maintain the arc, thus extinguishing it when the required voltage exceeds the available voltage. The arc extinguishing process with this invention is not dependent on the occurrence of a current zero crossing and, consequently, is capable of rapidly interrupting both AC and DC circuits. The contact structure achieves its high performance without the use of sulfur hexafluoride.

  9. High voltage AC/AC electrochemical capacitor operating at low temperature in salt aqueous electrolyte

    NASA Astrophysics Data System (ADS)

    Abbas, Qamar; Béguin, François

    2016-06-01

    We demonstrate that an activated carbon (AC)-based electrochemical capacitor implementing aqueous lithium sulfate electrolyte in 7:3 vol:vol water/methanol mixture can operate down to -40 °C with good electrochemical performance. Three-electrode cell investigations show that the faradaic contributions related with hydrogen chemisorption in the negative AC electrode are thermodynamically unfavored at -40 °C, enabling the system to work as a typical electrical double-layer (EDL) capacitor. After prolonged floating of the AC/AC capacitor at 1.6 V and -40°C, the capacitance, equivalent series resistance and efficiency remain constant, demonstrating the absence of ageing related with side redox reactions at this temperature. Interestingly, when temperature is increased back to 24 °C, the redox behavior due to hydrogen storage reappears and the system behaves as a freshly prepared one.

  10. Cryocooler operation of SNIS Josephson arrays for AC Voltage standards

    NASA Astrophysics Data System (ADS)

    Sosso, A.; De Leo, N.; Fretto, M.; Monticone, E.; Roncaglione, L.; Rocci, R.; Lacquaniti, V.

    2014-05-01

    Avoiding liquid helium is now a worldwide issue, thus cryocooler operation is becoming mandatory for a wider use of superconductive electronics. Josephson voltage standards hold a peculiar position among superconducting devices, as they are in use in high precision voltage metrology since decades. Higher temperature operation would reduce the refrigerator size and complexity, however, arrays of Josephson junctions made with high temperature superconductors for voltage standard applications are not to date available. The SNIS (Superconductor-Normal metal-Insulator-Superconductor) junction technology developed at INRIM, based on low temperature superconductors, but capable of operation well above liquid helium temperature, is interesting for application to a compact cryocooled standard, allowing to set a compromise between device and refrigerator requirements. In this work, the behavior of SNIS devices cooled with a closed-cycle refrigerator has been investigated, both in DC and under RF irradiation. Issues related to thermal design of the apparatus to solve specific problems not faced with liquid coolants, like reduced cooling power and minimization of thermal gradients for uniform operation of the chip are discussed in detail.

  11. Development of Low-Frequency AC Voltage Measurement System Using Single-Junction Thermal Converter

    NASA Astrophysics Data System (ADS)

    Amagai, Yasutaka; Nakamura, Yasuhiro

    Accurate measurement of low-frequency AC voltage using a digital multimeter at frequencies of 4-200Hz is a challenge in the mechanical engineering industry. At the National Metrology Institute of Japan, we developed a low-frequency AC voltage measurement system for calibrating digital multimeters operating at frequencies down to 1 Hz. The system uses a single-junction thermal converter and employs a theoretical model and a three-parameter sine wave fitting algorithm based on the least-square (LS) method. We calibrated the AC voltage down to 1Hz using our measurement system and reduced the measurement time compared with that using thin-film thermal converters. Our measurement results are verified by comparison with those of a digital sampling method using a high-resolution analog-to-digital converter; our data are in agreement to within a few parts in 105. Our proposed method enables us to measure AC voltage with an uncertainty of 25 μV/V (k = 1) at frequencies down to 4 Hz and a voltage of 10 V.

  12. Electronic Current Transducer (ECT) for high voltage dc lines

    NASA Astrophysics Data System (ADS)

    Houston, J. M.; Peters, P. H., Jr.; Summerayes, H. R., Jr.; Carlson, G. J.; Itani, A. M.

    1980-02-01

    The development of a bipolar electronic current transducer (ECT) for measuring the current in a high voltage dc (HVDC) power line at line potential is discussed. The design and construction of a free standing ECT for use on a 400 kV line having a nominal line current of 2000 A is described. Line current is measured by a 0.0001 ohm shunt whose voltage output is sampled by a 14 bit digital data link. The high voltage interface between line and ground is traversed by optical fibers which carry digital light signals as far as 300 m to a control room where the digital signal is converted back to an analog representation of the shunt voltage. Two redundant electronic and optical data links are used in the prototype. Power to operate digital and optical electronics and temperature controlling heaters at the line is supplied by a resistively and capacitively graded 10 stage cascade of ferrite core transformers located inside the hollow, SF6 filled, porcelain support insulator. The cascade is driven by a silicon controlled rectifier inverter which supplies about 100 W of power at 30 kHz.

  13. Statistical evaluation of telephone noise interference caused by AC power line harmonic currents

    SciTech Connect

    Kuussaari, M. )

    1993-04-01

    A statistical approach is applied for the evaluation of the limits for harmonic currents in AC power lines, the goal being to prevent excessive telephone noise interference voltages in subscriber cables in rural areas. The analysis is based on Monte-Carlo simulation which takes into account the effect of the experiental probability distributions of the relevant parameters. In the Finnish conditions, the properties of communication cables permit equivalent disturbing phase currents of 8 to 10 A. The digital exchanges permit approximately the same currents. Some new telephone types that have a low balance may make it necessary to limit the currents to a level that is somewhat lower.

  14. Nonlinear control of voltage source converters in AC-DC power system.

    PubMed

    Dash, P K; Nayak, N

    2014-07-01

    This paper presents the design of a robust nonlinear controller for a parallel AC-DC power system using a Lyapunov function-based sliding mode control (LYPSMC) strategy. The inputs for the proposed control scheme are the DC voltage and reactive power errors at the converter station and the active and reactive power errors at the inverter station of the voltage-source converter-based high voltage direct current transmission (VSC-HVDC) link. The stability and robust tracking of the system parameters are ensured by applying the Lyapunov direct method. Also the gains of the sliding mode control (SMC) are made adaptive using the stability conditions of the Lyapunov function. The proposed control strategy offers invariant stability to a class of systems having modeling uncertainties due to parameter changes and exogenous inputs. Comprehensive computer simulations are carried out to verify the proposed control scheme under several system disturbances like changes in short-circuit ratio, converter parametric changes, and faults on the converter and inverter buses for single generating system connected to the power grid in a single machine infinite-bus AC-DC network and also for a 3-machine two-area power system. Furthermore, a second order super twisting sliding mode control scheme has been presented in this paper that provides a higher degree of nonlinearity than the LYPSMC and damps faster the converter and inverter voltage and power oscillations.

  15. Nonlinear control of voltage source converters in AC-DC power system.

    PubMed

    Dash, P K; Nayak, N

    2014-07-01

    This paper presents the design of a robust nonlinear controller for a parallel AC-DC power system using a Lyapunov function-based sliding mode control (LYPSMC) strategy. The inputs for the proposed control scheme are the DC voltage and reactive power errors at the converter station and the active and reactive power errors at the inverter station of the voltage-source converter-based high voltage direct current transmission (VSC-HVDC) link. The stability and robust tracking of the system parameters are ensured by applying the Lyapunov direct method. Also the gains of the sliding mode control (SMC) are made adaptive using the stability conditions of the Lyapunov function. The proposed control strategy offers invariant stability to a class of systems having modeling uncertainties due to parameter changes and exogenous inputs. Comprehensive computer simulations are carried out to verify the proposed control scheme under several system disturbances like changes in short-circuit ratio, converter parametric changes, and faults on the converter and inverter buses for single generating system connected to the power grid in a single machine infinite-bus AC-DC network and also for a 3-machine two-area power system. Furthermore, a second order super twisting sliding mode control scheme has been presented in this paper that provides a higher degree of nonlinearity than the LYPSMC and damps faster the converter and inverter voltage and power oscillations. PMID:24906895

  16. 30 CFR 75.705 - Work on high-voltage lines; deenergizing and grounding.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Work on high-voltage lines; deenergizing and... Work on high-voltage lines; deenergizing and grounding. High-voltage lines, both on the surface and... permitted, in the case of energized surface high-voltage lines, if such repairs are made by a...

  17. 30 CFR 75.705 - Work on high-voltage lines; deenergizing and grounding.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Work on high-voltage lines; deenergizing and... Work on high-voltage lines; deenergizing and grounding. High-voltage lines, both on the surface and... permitted, in the case of energized surface high-voltage lines, if such repairs are made by a...

  18. 30 CFR 75.705 - Work on high-voltage lines; deenergizing and grounding.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Work on high-voltage lines; deenergizing and... Work on high-voltage lines; deenergizing and grounding. High-voltage lines, both on the surface and... permitted, in the case of energized surface high-voltage lines, if such repairs are made by a...

  19. 30 CFR 75.705 - Work on high-voltage lines; deenergizing and grounding.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Work on high-voltage lines; deenergizing and... Work on high-voltage lines; deenergizing and grounding. High-voltage lines, both on the surface and... permitted, in the case of energized surface high-voltage lines, if such repairs are made by a...

  20. High voltage gas insulated transmission line with continuous particle trapping

    DOEpatents

    Cookson, Alan H.; Dale, Steinar J.

    1983-01-01

    This invention provides a novel high voltage gas insulated transmission line utilizing insulating supports spaced at intervals with snap-in means for supporting a continuous trapping apparatus and said trapping apparatus having perforations and cutouts to facilitate trapping of contaminating particles and system flexibility.

  1. Metrological traceability for AC High-Voltage in Inmetro up to 40 kV

    NASA Astrophysics Data System (ADS)

    Vitorio, P. C. O.; de Lima, V. R.; Borges Filho, O.; de Souza, L. A. A.; Asencios, O. W. G.

    2016-07-01

    This paper refers to a project carried out in Inmetro aiming to provide internal metrological traceability for 60 Hz AC High-Voltage up to 40 kV. It presents details about the method used, its equations and obtained results. A capacitance and tanb bridge, with a built-in current comparator, was used in combination with two standard capacitors to calibrate a standard potential transformer (PT), both in ratio and phase angle. The results obtained by Inmetro showed good agreement with PTB ones, for the same PT. The maximum estimated uncertainty was 0,0049% for ratio error and 104 μrad for phase angle error.

  2. Spin Hall voltages from a.c. and d.c. spin currents

    PubMed Central

    Wei, Dahai; Obstbaum, Martin; Ribow, Mirko; Back, Christian H.; Woltersdorf, Georg

    2014-01-01

    In spin electronics, the spin degree of freedom is used to transmit and store information. To this end the ability to create pure spin currents—that is, without net charge transfer—is essential. When the magnetization vector in a ferromagnet–normal metal junction is excited, the spin pumping effect leads to the injection of pure spin currents into the normal metal. The polarization of this spin current is time-dependent and contains a very small d.c. component. Here we show that the large a.c. component of the spin currents can be detected efficiently using the inverse spin Hall effect. The observed a.c.-inverse spin Hall voltages are one order of magnitude larger than the conventional d.c.-inverse spin Hall voltages measured on the same device. Our results demonstrate that ferromagnet–normal metal junctions are efficient sources of pure spin currents in the gigahertz frequency range. PMID:24780927

  3. Self-monitoring high voltage transmission line suspension insulator

    DOEpatents

    Stemler, Gary E.; Scott, Donald N.

    1981-01-01

    A high voltage transmission line suspension insulator (18 or 22) which monitors its own dielectric integrity. A dielectric rod (10) has one larger diameter end fitting attachable to a transmission line and another larger diameter end fitting attachable to a support tower. The rod is enclosed in a dielectric tube (14) which is hermetically sealed to the rod's end fittings such that a liquidtight space (20) is formed between the rod and the tube. A pressurized dielectric liquid is placed within that space. A discoloring dye placed within this space is used to detect the loss of the pressurized liquid.

  4. Effects of electromagnetic fields produced by high voltage transmission lines

    NASA Astrophysics Data System (ADS)

    Young, T.

    1984-06-01

    The potential impacts of higher transmission line voltages on people, animals, and plants were determined. The differences among various studies are reviewed. Although there are some obvious dangers posed by transmission line operation, construction, and maintenance, most of these concerns are addressed by safety measures taken by utility companies. The indirect effects of power transission is reported. Three major categories of field effects are covered: (1) corona effects due to the electric field at the conductor's surface; (2) indirect coupling effects, arising from induced currents in nearby conducting objects; and (3) direct coupling effects, caused by induced currents in organisms.

  5. Generalised mc × nc -stage switched-capacitor-voltage-multiplier-based boost DC-AC inverter

    NASA Astrophysics Data System (ADS)

    Chang, Yuen-Haw; Wu, Ming-Zong

    2012-01-01

    A closed-loop scheme of a generalised ? -stage (multistage) switched-capacitor-voltage-multiplier inverter (SCVMI) is proposed by combining a two-phase interleaved phase generator and a sinusoidal-pulse-width-modulation (SPWM) control for low-power boost dc-ac conversion and regulation. In this SCVMI, the power unit contains two parts: SCVM booster (front) and H-bridge (rear). The SCVM booster is composed of two ? -stage SC cells and two ? -stage SC cells in series for a boost dc-dc conversion, and these cells are operated with two-phase non-overlapping clocks of phase generator for a high conversion ratio of ? at most (like a voltage multiplier). The H-bridge consists of four switches for a dc-ac conversion, and these switches are controlled by SPWM not only for realising full-wave operation, but also for enhancing output regulation as well as robustness to source/loading variation. Further, some aspects of theoretical analysis and design are included: SCVMI formulation, steady-state/dynamic analysis, conversion ratio, power efficiency, stability, capacitance selection, output filter and control design. Finally, the closed-loop SCVMI is simulated and the hardware implemented and tested. All the results are illustrated to show the efficacy of the proposed scheme.

  6. 30 CFR 77.704-2 - Repairs to energized high-voltage lines.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... UNDERGROUND COAL MINES Grounding § 77.704-2 Repairs to energized high-voltage lines. An energized high-voltage... performed only with the use of live line tools; and, (4) Weather conditions will not interfere with...

  7. 30 CFR 77.704-2 - Repairs to energized high-voltage lines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... UNDERGROUND COAL MINES Grounding § 77.704-2 Repairs to energized high-voltage lines. An energized high-voltage... performed only with the use of live line tools; and, (4) Weather conditions will not interfere with...

  8. 30 CFR 77.704-2 - Repairs to energized high-voltage lines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... UNDERGROUND COAL MINES Grounding § 77.704-2 Repairs to energized high-voltage lines. An energized high-voltage... performed only with the use of live line tools; and, (4) Weather conditions will not interfere with...

  9. Protection against lightning surge voltages on communication lines and power lines

    SciTech Connect

    Haseborg, J.L.t.; Trinks, H.

    1983-01-01

    Sensitive electronic systems are shielded against electromagnetic interferences (lightning, EMP). The shielding efficiency is reduced by field coupling through apertures and particularly by feeding of interfering currents through cable entries. In case these cables are connected to the inputs of electronic devices, the surge voltages may disturb or even destroy these devices or single electronic components, particularly semiconductors. Special passive protection circuits for communication and power lines against lightning- and EMP-induced surge voltages are developed. The edge steepnesses of the applying surge voltages show values of 2kV/us (lightning) up to 2kV/ns (EMP).

  10. 30 CFR 77.704-1 - Work on high-voltage lines.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Work on high-voltage lines. 77.704-1 Section 77... MINES Grounding § 77.704-1 Work on high-voltage lines. (a) No high-voltage line shall be regarded as... provided in § 77.103) that such high-voltage line has been deenergized and grounded. Such qualified...

  11. 30 CFR 77.704-1 - Work on high-voltage lines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Work on high-voltage lines. 77.704-1 Section 77... MINES Grounding § 77.704-1 Work on high-voltage lines. (a) No high-voltage line shall be regarded as... provided in § 77.103) that such high-voltage line has been deenergized and grounded. Such qualified...

  12. 30 CFR 75.705-3 - Work on energized high-voltage surface lines; reporting.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Work on energized high-voltage surface lines... Work on energized high-voltage surface lines; reporting. Any operator designating and assigning qualified persons to perform repairs on energized high-voltage surface lines under the provisions of §...

  13. 30 CFR 77.104 - Repair of energized surface high-voltage lines; qualified person.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Repair of energized surface high-voltage lines... high-voltage lines; qualified person. An individual is a qualified person within the meaning of § 77.704 of this part for the purpose of repairing energized surface high-voltage lines only if he has...

  14. 30 CFR 75.705-2 - Repairs to energized surface high-voltage lines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Repairs to energized surface high-voltage lines. 75.705-2 Section 75.705-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... Repairs to energized surface high-voltage lines. An energized high-voltage surface line may be...

  15. 30 CFR 75.154 - Repair of energized surface high voltage lines; qualified person.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Repair of energized surface high voltage lines... Certified Persons § 75.154 Repair of energized surface high voltage lines; qualified person. An individual... high voltage lines only if he has had at least 2 years experience in electrical maintenance, and...

  16. 30 CFR 77.704 - Work on high-voltage lines; deenergizing and grounding.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Work on high-voltage lines; deenergizing and... OF UNDERGROUND COAL MINES Grounding § 77.704 Work on high-voltage lines; deenergizing and grounding. High-voltage lines shall be deenergized and grounded before work is performed on them, except...

  17. 30 CFR 77.704-1 - Work on high-voltage lines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Work on high-voltage lines. 77.704-1 Section 77... AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Grounding § 77.704-1 Work on high-voltage lines. (a) No high-voltage line shall be regarded...

  18. 30 CFR 75.705-1 - Work on high-voltage lines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Work on high-voltage lines. 75.705-1 Section 75... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Grounding § 75.705-1 Work on high-voltage lines. (a) Section 75.705 specifically prohibits work on energized high-voltage lines underground;...

  19. 30 CFR 75.705-1 - Work on high-voltage lines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Work on high-voltage lines. 75.705-1 Section 75... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Grounding § 75.705-1 Work on high-voltage lines. (a) Section 75.705 specifically prohibits work on energized high-voltage lines underground;...

  20. 30 CFR 77.704-1 - Work on high-voltage lines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Work on high-voltage lines. 77.704-1 Section 77... AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Grounding § 77.704-1 Work on high-voltage lines. (a) No high-voltage line shall be regarded...

  1. 30 CFR 77.704-1 - Work on high-voltage lines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Work on high-voltage lines. 77.704-1 Section 77... AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Grounding § 77.704-1 Work on high-voltage lines. (a) No high-voltage line shall be regarded...

  2. 30 CFR 75.705-1 - Work on high-voltage lines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Work on high-voltage lines. 75.705-1 Section 75... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Grounding § 75.705-1 Work on high-voltage lines. (a) Section 75.705 specifically prohibits work on energized high-voltage lines underground;...

  3. 30 CFR 75.154 - Repair of energized surface high voltage lines; qualified person.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Repair of energized surface high voltage lines... Certified Persons § 75.154 Repair of energized surface high voltage lines; qualified person. An individual... high voltage lines only if he has had at least 2 years experience in electrical maintenance, and...

  4. 30 CFR 75.705-3 - Work on energized high-voltage surface lines; reporting.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Work on energized high-voltage surface lines... Work on energized high-voltage surface lines; reporting. Any operator designating and assigning qualified persons to perform repairs on energized high-voltage surface lines under the provisions of §...

  5. 30 CFR 75.154 - Repair of energized surface high voltage lines; qualified person.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Repair of energized surface high voltage lines... Certified Persons § 75.154 Repair of energized surface high voltage lines; qualified person. An individual... high voltage lines only if he has had at least 2 years experience in electrical maintenance, and...

  6. 30 CFR 77.704 - Work on high-voltage lines; deenergizing and grounding.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Work on high-voltage lines; deenergizing and... OF UNDERGROUND COAL MINES Grounding § 77.704 Work on high-voltage lines; deenergizing and grounding. High-voltage lines shall be deenergized and grounded before work is performed on them, except...

  7. 30 CFR 75.154 - Repair of energized surface high voltage lines; qualified person.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Repair of energized surface high voltage lines... Certified Persons § 75.154 Repair of energized surface high voltage lines; qualified person. An individual... high voltage lines only if he has had at least 2 years experience in electrical maintenance, and...

  8. 30 CFR 75.705-1 - Work on high-voltage lines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Work on high-voltage lines. 75.705-1 Section 75... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Grounding § 75.705-1 Work on high-voltage lines. (a) Section 75.705 specifically prohibits work on energized high-voltage lines underground;...

  9. 30 CFR 77.104 - Repair of energized surface high-voltage lines; qualified person.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Repair of energized surface high-voltage lines... high-voltage lines; qualified person. An individual is a qualified person within the meaning of § 77.704 of this part for the purpose of repairing energized surface high-voltage lines only if he has...

  10. 30 CFR 77.704 - Work on high-voltage lines; deenergizing and grounding.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Work on high-voltage lines; deenergizing and... OF UNDERGROUND COAL MINES Grounding § 77.704 Work on high-voltage lines; deenergizing and grounding. High-voltage lines shall be deenergized and grounded before work is performed on them, except...

  11. 30 CFR 77.704 - Work on high-voltage lines; deenergizing and grounding.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Work on high-voltage lines; deenergizing and... OF UNDERGROUND COAL MINES Grounding § 77.704 Work on high-voltage lines; deenergizing and grounding. High-voltage lines shall be deenergized and grounded before work is performed on them, except...

  12. 30 CFR 75.705-1 - Work on high-voltage lines.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Work on high-voltage lines. 75.705-1 Section 75... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Grounding § 75.705-1 Work on high-voltage lines. (a) Section 75.705 specifically prohibits work on energized high-voltage lines underground;...

  13. 30 CFR 75.705-3 - Work on energized high-voltage surface lines; reporting.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Work on energized high-voltage surface lines... Work on energized high-voltage surface lines; reporting. Any operator designating and assigning qualified persons to perform repairs on energized high-voltage surface lines under the provisions of §...

  14. 30 CFR 77.104 - Repair of energized surface high-voltage lines; qualified person.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Repair of energized surface high-voltage lines... high-voltage lines; qualified person. An individual is a qualified person within the meaning of § 77.704 of this part for the purpose of repairing energized surface high-voltage lines only if he has...

  15. 30 CFR 77.104 - Repair of energized surface high-voltage lines; qualified person.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Repair of energized surface high-voltage lines... high-voltage lines; qualified person. An individual is a qualified person within the meaning of § 77.704 of this part for the purpose of repairing energized surface high-voltage lines only if he has...

  16. 30 CFR 75.705-3 - Work on energized high-voltage surface lines; reporting.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Work on energized high-voltage surface lines... Work on energized high-voltage surface lines; reporting. Any operator designating and assigning qualified persons to perform repairs on energized high-voltage surface lines under the provisions of §...

  17. 30 CFR 77.807-3 - Movement of equipment; minimum distance from high-voltage lines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... high-voltage lines. 77.807-3 Section 77.807-3 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.807-3 Movement of equipment; minimum distance from high-voltage lines. When any part of any equipment operated on the surface of...

  18. 30 CFR 77.807-3 - Movement of equipment; minimum distance from high-voltage lines.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... high-voltage lines. 77.807-3 Section 77.807-3 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.807-3 Movement of equipment; minimum distance from high-voltage lines. When any part of any equipment operated on the surface of...

  19. 30 CFR 77.807-3 - Movement of equipment; minimum distance from high-voltage lines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... high-voltage lines. 77.807-3 Section 77.807-3 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.807-3 Movement of equipment; minimum distance from high-voltage lines. When any part of any equipment operated on the surface of...

  20. 30 CFR 77.807-3 - Movement of equipment; minimum distance from high-voltage lines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... high-voltage lines. 77.807-3 Section 77.807-3 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.807-3 Movement of equipment; minimum distance from high-voltage lines. When any part of any equipment operated on the surface of...

  1. Monolithic high voltage nonlinear transmission line fabrication process

    DOEpatents

    Cooper, Gregory A.

    1994-01-01

    A process for fabricating sequential inductors and varactor diodes of a monolithic, high voltage, nonlinear, transmission line in GaAs is disclosed. An epitaxially grown laminate is produced by applying a low doped active n-type GaAs layer to an n-plus type GaAs substrate. A heavily doped p-type GaAs layer is applied to the active n-type layer and a heavily doped n-type GaAs layer is applied to the p-type layer. Ohmic contacts are applied to the heavily doped n-type layer where diodes are desired. Multiple layers are then either etched away or Oxygen ion implanted to isolate individual varactor diodes. An insulator is applied between the diodes and a conductive/inductive layer is thereafter applied on top of the insulator layer to complete the process.

  2. Monolithic high voltage nonlinear transmission line fabrication process

    DOEpatents

    Cooper, G.A.

    1994-10-04

    A process for fabricating sequential inductors and varistor diodes of a monolithic, high voltage, nonlinear, transmission line in GaAs is disclosed. An epitaxially grown laminate is produced by applying a low doped active n-type GaAs layer to an n-plus type GaAs substrate. A heavily doped p-type GaAs layer is applied to the active n-type layer and a heavily doped n-type GaAs layer is applied to the p-type layer. Ohmic contacts are applied to the heavily doped n-type layer where diodes are desired. Multiple layers are then either etched away or Oxygen ion implanted to isolate individual varistor diodes. An insulator is applied between the diodes and a conductive/inductive layer is thereafter applied on top of the insulator layer to complete the process. 6 figs.

  3. A Field Study of Lightning Overvoltages on Low-voltage Distribution Lines

    NASA Astrophysics Data System (ADS)

    Ishii, Tsunayoshi; Oguchi, Syuichi; Sakamoto, Yoshiki; Okabe, Shigemitsu

    Recently, the number of home electric appliances, such as personal computers and telephones, is rapidly increased. Lightning damage to these home electric appliances has a great impact on highly sophisticated information society. There are some cases that lightning overvoltages on low-voltage distribution lines cause malfunction of them, though they equipped surge protective devices to protect against lightning overvoltages. Therefore, for lightning protection of low-voltage equipments including home electric appliances, it's important to understand the phenomenon of lightning overvoltages on low-voltage distribution lines. However, it's not so clear including the generation of them. The Tokyo Electric Power Company carries out the lightning observation on low-voltage distribution lines. The observation results provide the statistical distribution of lightning overvoltages on low-voltage distribution lines. The generation mechanism of lightning overvoltages on low-voltage distribution lines is assumed based on observed waveforms and facilities data.

  4. 30 CFR 77.704-2 - Repairs to energized high-voltage lines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Repairs to energized high-voltage lines. 77.704-2 Section 77.704-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL... UNDERGROUND COAL MINES Grounding § 77.704-2 Repairs to energized high-voltage lines. An energized...

  5. 30 CFR 77.704-3 - Work on energized high-voltage surface lines; reporting.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Work on energized high-voltage surface lines... OF UNDERGROUND COAL MINES Grounding § 77.704-3 Work on energized high-voltage surface lines; reporting. Any operator designating and assigning qualified persons to perform repairs on energized...

  6. 40 CFR Table B-4 to Subpart B of... - Line Voltage and Room Temperature Test Conditions

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 6 2013-07-01 2013-07-01 false Line Voltage and Room Temperature Test... B-4 Table B-4 to Subpart B of Part 53—Line Voltage and Room Temperature Test Conditions Test day... Temperatures shall be controlled to ± 1 °C....

  7. 30 CFR 77.704-3 - Work on energized high-voltage surface lines; reporting.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Work on energized high-voltage surface lines... OF UNDERGROUND COAL MINES Grounding § 77.704-3 Work on energized high-voltage surface lines; reporting. Any operator designating and assigning qualified persons to perform repairs on energized...

  8. 30 CFR 77.704-3 - Work on energized high-voltage surface lines; reporting.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Work on energized high-voltage surface lines... OF UNDERGROUND COAL MINES Grounding § 77.704-3 Work on energized high-voltage surface lines; reporting. Any operator designating and assigning qualified persons to perform repairs on energized...

  9. 30 CFR 77.704-3 - Work on energized high-voltage surface lines; reporting.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Work on energized high-voltage surface lines... OF UNDERGROUND COAL MINES Grounding § 77.704-3 Work on energized high-voltage surface lines; reporting. Any operator designating and assigning qualified persons to perform repairs on energized...

  10. 30 CFR 75.705 - Work on high-voltage lines; deenergizing and grounding.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Work on high-voltage lines; deenergizing and grounding. 75.705 Section 75.705 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Grounding § 75.705 Work on high-voltage lines; deenergizing...

  11. System and component design and test of a 10 hp, 18,000 rpm AC dynamometer utilizing a high frequency AC voltage link, part 1

    NASA Technical Reports Server (NTRS)

    Lipo, Thomas A.; Alan, Irfan

    1991-01-01

    Hard and soft switching test results conducted with one of the samples of first generation MOS-controlled thyristor (MCTs) and similar test results with several different samples of second generation MCT's are reported. A simple chopper circuit is used to investigate the basic switching characteristics of MCT under hard switching and various types of resonant circuits are used to determine soft switching characteristics of MCT under both zero voltage and zero current switching. Next, operation principles of a pulse density modulated converter (PDMC) for three phase (3F) to 3F two-step power conversion via parallel resonant high frequency (HF) AC link are reviewed. The details for the selection of power switches and other power components required for the construction of the power circuit for the second generation 3F to 3F converter system are discussed. The problems encountered in the first generation system are considered. Design and performance of the first generation 3F to 3F power converter system and field oriented induction moter drive based upon a 3 kVA, 20 kHz parallel resonant HF AC link are described. Low harmonic current at the input and output, unity power factor operation of input, and bidirectional flow capability of the system are shown via both computer and experimental results. The work completed on the construction and testing of the second generation converter and field oriented induction motor drive based upon specifications for a 10 hp squirrel cage dynamometer and a 20 kHz parallel resonant HF AC link is discussed. The induction machine is designed to deliver 10 hp or 7.46 kW when operated as an AC-dynamo with power fed back to the source through the converter. Results presented reveal that the proposed power level requires additional energy storage elements to overcome difficulties with a peak link voltage variation problem that limits reaching to the desired power level. The power level test of the second generation converter after the

  12. Coupling an induction motor type generator to ac power lines. [making windmill generators compatible with public power lines

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1984-01-01

    A system for coupling an induction motor type generator to an A.C. power line includes an electronic switch means that is controlled by a control system and is regulated to turn on at a relatively late point in each half cycle of its operation. The energizing power supplied by the line to the induction motor type generator is decreased and the net power delivered to the line is increased.

  13. WATER QUALITY AND TREATMENT CONSIDERATIONS FOR CEMENT-LINED AND A-C PIPE

    EPA Science Inventory

    Both cement mortar lined (CML) and asbestos-cement pipes (A-C) are widely used in many water systems. Cement linings are also commonly applied in-situ after pipe cleaning, usually to prevent the recurrence of red water or tuberculation problems. Unfortunately, little consideratio...

  14. New live line tester for porcelain suspension insulators on high-voltage power lines

    SciTech Connect

    Vaillancourt, G.H.; St-Jean, M. ); Bellerive, J.P. ); Jean, C. )

    1994-01-01

    Suspension insulator assemblies known as insulator strings are used in overhead power transmission lines to mechanically support high-voltage conductors while providing adequate insulation to withstand switching and lightning overvoltages. Since the useful life in service of the individual insulator elements making up these strings is hard to predict, they must be verified periodically to insure that adequate line reliability is maintained at all times. Over the years many testing methods have been used for this purpose, each one with its own advantages and disadvantages. Until now at Hydro-Quebec, porcelain insulators had been tested by the buzz method which simply consists of applying a short-circuit to each insulator in a string and listening for a buzz-like sound indicating a good insulator. However, safety considerations that preclude short-circuiting insulators and other disadvantages of that method have led Hydro-Quebec to undertake and complete the development of a new insulator tester. The working principle of this new device is based on the automatic measurement and recording of the electric field along the insulator string which decreases considerably in front of an internally-shorted insulator. The tester is slid along the string while the insulators are counted automatically. The information from tests on up to 200 strings can be stored in the device to be later transferred in a host computer for interpretation and/or permanent storage. The new tester also gives information on voltage distribution along the insulator strings which can be useful for the design of future power transmission lines.

  15. Why an ac magnetic field shifts the irreversibility line in type-II superconductors.

    PubMed

    Brandt, Ernst Helmut; Mikitik, Grigorii P

    2002-07-01

    We show that for a thin superconducting strip placed in a transverse dc magnetic field--the typical geometry of experiments with high-T(c) superconductors--the application of a weak ac magnetic field perpendicular to the dc field generates a dc voltage in the strip. This voltage leads to the decay of the critical currents circulating in the strip, and eventually the equilibrium state of the superconductor is established. This relaxation is not due to thermally activated flux creep but to the "walking" motion of vortices in the two-dimensional critical state of the strip with in-plane ac field. Our theory explains the shaking effect that was used for detecting phase transitions of the vortex lattice in superconductors.

  16. Study of the Dependency on Magnetic Field and Bias Voltage of an AC-Biased TES Microcalorimeter

    NASA Technical Reports Server (NTRS)

    Gottardi, L.; Bruijn, M.; denHartog, R.; Hoevers, H.; deKorte, P.; vanderKuur, J.; Linderman, M.; Adams, J.; Bailey, C.; Bandler, S.; Chervenak, J.; Eckart, M.; Finkbeiner, F.; Kelley, R.; Kilbourne, C.; Porter, F.; Sadlier, J.; Smith, S.

    2012-01-01

    At SRON we are studying the performance of a Goddard Space Flight Center single pixel TES microcalorimeter operated in an AC bias configuration. For x-ray photons at 6 keV the pixel shows an x-ray energy resolution Delta E(sub FWHM) = 3.7 eV, which is about a factor 2 worse than the energy resolution observed in an identical DC-biased pixel. In order to better understand the reasons for this discrepancy we characterized the detector as a function of temperature, bias working point and applied perpendicular magnetic field. A strong periodic dependency of the detector noise on the TES AC bias voltage is measured. We discuss the results in the framework of the recently observed weak-link behaviour of a TES microcalorimeter.

  17. Analysis of three-phase rectifiers with AC-side switches and interleaved three-phase voltage-source converters

    NASA Astrophysics Data System (ADS)

    Miller, Stephanie Katherine Teixeira

    Of all the alternative and renewable energy sources, wind power is the fastest growing alternative energy source with a total worldwide capacity of over 93 GW as of the end of 2007. However, making wind energy a sustainable and reliable source of electricity doesn't come without its set of challenges. As the wind turbines increase in size and turbine technology moves towards off-shore wind farms and direct drive transmission, the need for a reliable and efficient power electronics interface to convert the variable-frequency variable-magnitude output of the wind turbine's generator into the fixed-frequency fixed-magnitude voltage of the utility grid is critical. This dissertation investigates a power electronics interface envisioned to operate with an induction generator-based variable-speed wind turbine. The research conclusions and the interface itself are applicable to a variety of applications, including uninterruptible power supplies, industrial drives, and power quality applications, among others. The three-phase PWM rectifiers with ac-side bidirectional switches are proposed as the rectification stage of the power electronics interface. Modulation strategies are proposed for the rectifiers and the operation of the rectifiers in conjunction with an induction generator is demonstrated. The viability of using these rectifiers in place of the standard three-phase voltage-source converter is analyzed by comparing losses and common-mode voltage generation of the two topologies. Parallel three-phase voltage-source converter modules operated in an interleaved fashion are proposed for the inversion stage of the power electronics interface. The interleaved three-phase voltage-source converters are analyzed by deriving analytical models for the common-mode voltage, ac phase current, and dc-link current to reveal their spectra and the harmonic cancellation effects of interleaving. The practical problem of low frequency circulating current in parallel voltage

  18. 30 CFR 77.807-2 - Booms and masts; minimum distance from high-voltage lines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.807-2 Booms and masts; minimum distance from high-voltage lines. The booms and masts of equipment operated on the surface of any... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Booms and masts; minimum distance from...

  19. 30 CFR 56.12071 - Movement or operation of equipment near high-voltage power lines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... NONMETAL MINES Electricity § 56.12071 Movement or operation of equipment near high-voltage power lines. When equipment must be moved or operated near energized high-voltage powerlines (other than trolley... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Movement or operation of equipment near...

  20. 30 CFR 77.807-2 - Booms and masts; minimum distance from high-voltage lines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.807-2 Booms and masts; minimum distance from high-voltage lines. The booms and masts of equipment operated on the surface of any... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Booms and masts; minimum distance from...

  1. 30 CFR 56.12071 - Movement or operation of equipment near high-voltage power lines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... NONMETAL MINES Electricity § 56.12071 Movement or operation of equipment near high-voltage power lines. When equipment must be moved or operated near energized high-voltage powerlines (other than trolley... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Movement or operation of equipment near...

  2. 30 CFR 77.807-2 - Booms and masts; minimum distance from high-voltage lines.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.807-2 Booms and masts; minimum distance from high-voltage lines. The booms and masts of equipment operated on the surface of any... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Booms and masts; minimum distance from...

  3. 30 CFR 56.12071 - Movement or operation of equipment near high-voltage power lines.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... NONMETAL MINES Electricity § 56.12071 Movement or operation of equipment near high-voltage power lines. When equipment must be moved or operated near energized high-voltage powerlines (other than trolley... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Movement or operation of equipment near...

  4. 30 CFR 77.807-2 - Booms and masts; minimum distance from high-voltage lines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.807-2 Booms and masts; minimum distance from high-voltage lines. The booms and masts of equipment operated on the surface of any... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Booms and masts; minimum distance from...

  5. 30 CFR 56.12071 - Movement or operation of equipment near high-voltage power lines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... NONMETAL MINES Electricity § 56.12071 Movement or operation of equipment near high-voltage power lines. When equipment must be moved or operated near energized high-voltage powerlines (other than trolley... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Movement or operation of equipment near...

  6. 33 CFR 165.T01-0992 - Safety Zone; repair of high voltage transmission lines to Logan International Airport; Saugus...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... voltage transmission lines to Logan International Airport; Saugus River, Saugus, MA. 165.T01-0992 Section... high voltage transmission lines to Logan International Airport; Saugus River, Saugus, MA. (a) General... high voltage transmission lines to Logan International Airport; Saugus River, Saugus, MA. (i)...

  7. Study and Experiment on Non-Contact Voltage Sensor Suitable for Three-Phase Transmission Line.

    PubMed

    Zhou, Qiang; He, Wei; Xiao, Dongping; Li, Songnong; Zhou, Kongjun

    2015-12-30

    A voltage transformer, as voltage signal detection equipment, plays an important role in a power system. Presently, more and more electric power systems are adopting potential transformer and capacitance voltage transformers. Transformers are often large in volume and heavyweight, their insulation design is difficult, and an iron core or multi-grade capacitance voltage division structure is generally adopted. As a result, the detection accuracy of transformer is reduced, a huge phase difference exists between detection signal and voltage signal to be measured, and the detection signal cannot accurately and timely reflect the change of conductor voltage signal to be measured. By aiming at the current problems of electric transformation, based on electrostatic induction principle, this paper designed a non-contact voltage sensor and gained detection signal of the sensor through electrostatic coupling for the electric field generated by electric charges of the conductor to be measured. The insulation structure design of the sensor is simple and its volume is small; phase difference of sensor measurement is effectively reduced through optimization design of the electrode; and voltage division ratio and measurement accuracy are increased. The voltage sensor was tested on the experimental platform of simulating three-phase transmission line. According to the result, the designed non-contact voltage sensor can realize accurate and real-time measurement for the conductor voltage. It can be applied to online monitoring for the voltage of three-phase transmission line or three-phase distribution network line, which is in accordance with the development direction of the smart grid.

  8. Study and Experiment on Non-Contact Voltage Sensor Suitable for Three-Phase Transmission Line

    PubMed Central

    Zhou, Qiang; He, Wei; Xiao, Dongping; Li, Songnong; Zhou, Kongjun

    2015-01-01

    A voltage transformer, as voltage signal detection equipment, plays an important role in a power system. Presently, more and more electric power systems are adopting potential transformer and capacitance voltage transformers. Transformers are often large in volume and heavyweight, their insulation design is difficult, and an iron core or multi-grade capacitance voltage division structure is generally adopted. As a result, the detection accuracy of transformer is reduced, a huge phase difference exists between detection signal and voltage signal to be measured, and the detection signal cannot accurately and timely reflect the change of conductor voltage signal to be measured. By aiming at the current problems of electric transformation, based on electrostatic induction principle, this paper designed a non-contact voltage sensor and gained detection signal of the sensor through electrostatic coupling for the electric field generated by electric charges of the conductor to be measured. The insulation structure design of the sensor is simple and its volume is small; phase difference of sensor measurement is effectively reduced through optimization design of the electrode; and voltage division ratio and measurement accuracy are increased. The voltage sensor was tested on the experimental platform of simulating three-phase transmission line. According to the result, the designed non-contact voltage sensor can realize accurate and real-time measurement for the conductor voltage. It can be applied to online monitoring for the voltage of three-phase transmission line or three-phase distribution network line, which is in accordance with the development direction of the smart grid. PMID:26729119

  9. Gates to Gregg High Voltage Transmission Line Study. [California

    NASA Technical Reports Server (NTRS)

    Bergis, V.; Maw, K.; Newland, W.; Sinnott, D.; Thornbury, G.; Easterwood, P.; Bonderud, J.

    1982-01-01

    The usefulness of LANDSAT data in the planning of transmission line routes was assessed. LANDSAT digital data and image processing techniques, specifically a multi-date supervised classification aproach, were used to develop a land cover map for an agricultural area near Fresno, California. Twenty-six land cover classes were identified, of which twenty classes were agricultural crops. High classification accuracies (greater than 80%) were attained for several classes, including cotton, grain, and vineyards. The primary products generated were 1:24,000, 1:100,000 and 1:250,000 scale maps of the classification and acreage summaries for all land cover classes within four alternate transmission line routes.

  10. Electrical Experiments. VT-214-12-4. Part IV. A-C Reduced Voltage Controls.

    ERIC Educational Resources Information Center

    Connecticut State Dept. of Education, Hartford. Div. of Vocational Education.

    Designed for high school electronics students, this fourth document in a series of six electrical learning activity packages focuses on alternating current-reduced voltage controls. An introductory section gives the objective for the activities, an introduction, and an outline of the content. The remainder of the guidebook is comprised of…

  11. Wireless power transfer and fault diagnosis of high-voltage power line via robotic bird

    NASA Astrophysics Data System (ADS)

    Liu, Chunhua; Chau, K. T.; Zhang, Zhen; Qiu, Chun; Li, Wenlong; Ching, T. W.

    2015-05-01

    This paper presents a new idea of wireless power transfer (WPT) and fault diagnosis (FD) of high-voltage power line via robotic bird. The key is to present the conceptual robotic bird with WPT coupling coil for detecting and capturing the energy from the high-voltage power line. If the power line works in normal condition, the robotic bird is able to stand on the power line and extract energy from it. If fault occurs on the power line, the corresponding magnetic field distribution will become different from that in the normal situation. By analyzing the magnetic field distribution of the power line, the WPT to the robotic bird and the FD by the robotic bird are performed and verified.

  12. Higher harmonics in voltage on superconductor carrying AC current due to non-linear I- V curve

    NASA Astrophysics Data System (ADS)

    Janíková, Edita; Gömöry, Fedor; Šouc, Ján

    2004-01-01

    When superconducting wire carries AC current with amplitude exceeding its critical current, additional losses appear due to non-zero resistivity. The voltage attributed to this mechanism will contain higher harmonics because of non-linear I- V curve of superconducting material. This curve can be derived using the following simple model: parallel combination of superconductor standing for the properties of all the filaments and the normal resistor representing the matrix. I- V relation is then characterized by three parameters: the critical current, I0, the n-exponent, n, and the ratio of the cross-section to the resistivity of metallic matrix. Expressions for Fourier coefficients have been calculated for this model. Extensive analysis of the influence that the model parameters exhibit on higher harmonics have revealed some useful features: 3rd harmonic could be nicely used to detect I0 and n, while from the maximum of 5th harmonic the value of matrix resistivity can be estimated.

  13. 30 CFR 75.705-3 - Work on energized high-voltage surface lines; reporting.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Work on energized high-voltage surface lines; reporting. 75.705-3 Section 75.705-3 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Grounding § 75.705-3 Work on energized high-voltage...

  14. Design and realization of the low voltage power line carrier channel simulation platform

    NASA Astrophysics Data System (ADS)

    Zhang, Xuhui; Zhang, Liyong; Zou, Bing; Zhang, Xuhai

    2006-11-01

    Proposed a visualized modeling and simulating scheme on the basis of object-oriented software for the power line communication channels. Combined with the research on the theories about transmitting lines, applies a equivalent concentrated parameter model to replace the traditional distributed parameter model of the transmitting lines, and studied the realizing process of the simulation. Constructed the network topology model database, noise model database, typical load model database aiming at the low-voltage power line features. And developed a visual, easy-to-operate power line communication simulation platform under Windows operation system.

  15. Effects of high-voltage transmission lines on honeybees

    SciTech Connect

    Greenberg, B.; Bindokas, V.P.; Gauger, J.R.

    1985-05-01

    When shielded and exposed colonies were placed at incremental distances at a right angle from a 760-kV transmission line different thresholds for biologic effects were obtained. Hive exposures were controlled (E-field: 7, 5.5, 4.1, 1.8, and 0.65 to 0.85 kV/m) by variable height current collectors; shielded hives under the line behave normally. Exposure to 7 kV/m can produce the following sequence of events: (1) increased motor activity and transient hive temperature increase; (2) abnormal propolization; (3) retarded hive weight gain; (4) excess queen cell production with queen loss; (5) reduction of sealed brood area; and (6) poor winter survival. No biological effects were detected below 4.1 kV/m, thus the ''biological effects corridor'' is limited to approximately 23 m beyond a ground projection of each outer phase wire. Hive architecture enhances E-fields and creates shock hazards for bees. Intra-hive E-fields (15 to 100+ kV/m) were measured with a displacement current sensor and fiber optic telemetry link. Step-potential-induced currents up to 0.5 uA were measured with a bee model in hives at 7 kV/m. To investigate further the role of shock versus electric field exposure the study was continued to develop hive entrance extensions (porches), which produce controlled bee exposure to E-field or shock, and to test the feasibility of using these porches in such a study. Biological effects (e.g., abnormal propolization, retarded hive weight, queen loss) found in colonies with total-hive exposure were produced by entrance-only exposure of adult bees. We now have an exposure system in which E-field and shock can be separately controlled to reproduce the biological effects. 10 refs.

  16. Characteristics of plasma sterilizer using microwave torch plasma with AC high-voltage discharge plasma

    NASA Astrophysics Data System (ADS)

    Itarashiki, Tomomasa; Hayashi, Nobuya; Yonesu, Akira

    2016-01-01

    Microwave plasma sterilization has recently been attracting attention for medical applications. However, it is difficult to perform low-temperature sterilization in short time periods. Increasing the output power shortens the time required for sterilization but causes the temperature to increase. To overcome this issue, we have developed a hybrid plasma system that combines a microwave torch plasma and a high-voltage mesh plasma, which allows radicals to be produced at low temperatures. Using this system, successful sterilization was shown to be possible in a period of 45 min at a temperature of 41 °C.

  17. Bias-voltage-controlled ac and dc magnetotransport phenomena in hybrid structures

    NASA Astrophysics Data System (ADS)

    Volkov, N. V.; Tarasov, A. S.; Smolyakov, D. A.; Varnakov, S. N.; Ovchinnikov, S. G.

    2015-06-01

    We report some ac and dc magnetotransport phenomena in silicon-based hybrid structures. The giant impedance change under an applied magnetic field has been experimentally found in the metal/insulator/semiconductor (MIS) diode with the Schottky barrier based on the Fe/SiO2/p-Si and Fe/SiO2/n-Si structures. The maximum effect is found to observe at temperatures of 10-30 K in the frequency range 10 Hz-1 MHz. Below 1 kHz the magnetoresistance can be controlled in a wide range by applying a bias to the device. A photoinduced dc magnetoresistance of over 104% has been found in the Fe/SiO2/p-Si back-to-back Schottky diode. The observed magnetic-field-dependent effects are caused by the interface states localized in the insula-tor/semiconductor interface.

  18. Final report on COOMET.EM-S5: Supplementary comparison of AC voltage ratio standards (COOMET project 396/UA/07)

    NASA Astrophysics Data System (ADS)

    Kikalo, V. N.; Petrovich, M. L.; Lobzhanidze, N. G.; Kisilev, V. V.; Styblikova, R.

    2013-01-01

    The comparison COOMET No 396/UA/07 of AC voltage ratio standards is registered in the BIPM key comparison database (KCDB) as supplementary comparison COOMET.EM-S5. It was conducted from June 2008 to July 2010 and involved the National Metrology Institutes of the Republic of Belarus, Georgia, the Russian Federation, the Czech Republic and Ukraine. SE "Ukrmetrteststandard" (Ukraine) was the Pilot laboratory for this exercise. The final report lists all data of measurement results and declared uncertainties as obtained by the participating NMIs. The degrees to which the values of the national standards correspond to the reference values of the supplementary comparison are quantitatively evaluated with the conclusions that the results obtained are recognized to be consistent taking into account the declared uncertainties. This gives evidence for supporting the corresponding Calibration and Measurement Capabilities for those values of voltage ratio at which NMIs have performed measurements. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by COOMET, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  19. Emission lines in the spectra of the RV Tauri stars U Monocerotis and AC Herculis

    NASA Technical Reports Server (NTRS)

    Bopp, B. W.

    1984-01-01

    Strong metallic emission lines have been observed in the spectra of the RV Tauri stars U Mon and AC Her near recent light minima. While these two variables differ in a number of significant respects, the metallic emission spectra are quite similar, resembling the emission that was previously reported as present in the spectrum of R Sct at a deep minimum. The data appear to support Baird's shock-wave model for the spectral behavior of RV Tauri stars.

  20. Effects of high-voltage transmission lines on honey bees

    SciTech Connect

    Greenberg, B.; Bindokas, V.P.

    1981-04-01

    Data are reported on the effect of hive height and current distribution on honey bees hived under a 765 kV line (E-field ca. 7 kV/m). Hive height was standardized with adjustable collectors to 1 meter (59 ..mu..A total hive current) or 1.5 meter (85 ..mu..A) equivalents; controls were shielded. A 1.5 meter group with completely painted supers was included. After 8 or 16 weeks of exposure there was no effect on honey moisture content or weight of young workers in any group. Worker capped brood was not affected in 1 m hives but declined significantly in 1.5 m hives after 4 weeks of exposure and this was associated with queen loss, abnormal queen cell production, and colony failure. Weight gain was depressed in all hives after 2 weeks of exposure and was dose related, with the taller hives more severely affected. Only the exposed hives propolized entrances but the amount and time of onset were not dose related. The 1.5 m hives with painted interiors behaved like the 1 m hives with unpainted interiors in all respects, although their total hive current approximated the other group of 1.5 m hives. Reversal of treatments at midseason resulted in reversal of colony behavior, manifested most clearly with respect to hive weight, less with respect to brood. When first exposed, colonies exhibit pronounced but transient elevations in hive temperature. Bio-effects were more severe during the first period when hives had fewer bees. Total hive current was greater in wet than in dry periods. All these factors influence observed bioeffects.

  1. Test Results From a Simulated High-Voltage Lunar Power Transmission Line

    NASA Technical Reports Server (NTRS)

    Birchenough, Arthur; Hervol, David

    2008-01-01

    The Alternator Test Unit (ATU) in the Lunar Power System Facility (LPSF) located at the NASA Glenn Research Center (GRC) in Cleveland, Ohio was modified to simulate high-voltage transmission capability. The testbed simulated a 1 km transmission cable length from the ATU to the LPSF using resistors and inductors installed between the distribution transformers. Power factor correction circuitry was used to compensate for the reactance of the distribution system to improve the overall power factor. This test demonstrated that a permanent magnet alternator can successfully provide high-frequency ac power to a lunar facility located at a distance.

  2. Test Results from a Simulated High Voltage Lunar Power Transmission Line

    NASA Technical Reports Server (NTRS)

    Birchenough, Arthur; Hervol, David

    2008-01-01

    The Alternator Test Unit (ATU) in the Lunar Power System Facility (LPSF) located at the NASA Glenn Research Center (GRC) in Cleveland, OH was modified to simulate high voltage transmission capability. The testbed simulated a 1 km transmission cable length from the ATU to the LPSF using resistors and inductors installed between the distribution transformers. Power factor correction circuitry was used to compensate for the reactance of the distribution system to improve the overall power factor. This test demonstrated that a permanent magnet alternator can successfully provide high frequency AC power to a lunar facility located at a distance.

  3. Revealing the charge transport mechanism of a photoelectrochemical cell: analysis using A.C. voltage perturbation.

    PubMed

    Patel, Dipal B; Chauhan, Khushbu R; Mukhopadhyay, Indrajit

    2014-10-14

    In this paper, we have carefully investigated the operation of a photoelectrochemical (PEC) cell configured of PbOx|Fe(CN)6(-4/-3)|Pt in the accumulation, flat band, depletion, inversion and deep-depletion regions using impedance measurements. The increases in the photocurrent for the different regions differ in their nature: a logarithmic increase in the depletion region, a linear increase in the inversion region along with a linear increase in the dark current and an exponential increase in the photo- and dark current in the deep-depletion region. All these variations are studied in detail to correlate these observations to the charge transfer mechanisms. The characteristics of the impedance spectrum itself can be assigned to the mentioned regions. We have found that the maximum photocurrent of the PEC cell, in the present investigation, can be extracted when the cell is working in the inversion region, while the maximum rate of the increase in photocurrent is found when the junction behaves as an ideal Schottky diode with a single RC element. Systematic experiments are suggested to establish a correlation between the observations obtained from the photocurrent, impedance, conductance, low frequency and high frequency capacitance measurements. It was found that light induced trap states in the semiconductor limit the photocurrent which has a linear dependency on the irradiance. A detailed investigation with A.C. conductivity measurements showed that the trap states actively participate in the current mechanism via a hopping phenomenon with small activation energies of 0.2 and 0.8 meV. The hopping rate increased exponentially with the applied bias under dark and illumination conditions. We also show a new way of finding the potential at which the maximum photocurrent will be extracted from the PEC cell, wherein the hopping via trap states is a dominating charge transfer mechanism. This study will help in pin pointing the key affecting parameters which limit the

  4. 40 CFR Table B-4 to Subpart B of... - Line Voltage and Room Temperature Test Conditions

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Conditions B Table B-4 to Subpart B of Part 53 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Testing Performance Characteristics of Automated Methods for SO2, CO, O3, and NO2 Pt. 53, Subpt. B, Table B-4 Table B-4 to Subpart B of Part 53—Line Voltage and Room Temperature Test Conditions Test...

  5. 40 CFR Table B-4 to Subpart B of... - Line Voltage and Room Temperature Test Conditions

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Conditions B Table B-4 to Subpart B of Part 53 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Testing Performance Characteristics of Automated Methods for SO2, CO, O3, and NO2 Pt. 53, Subpt. B, Table B-4 Table B-4 to Subpart B of Part 53—Line Voltage and Room Temperature Test Conditions Test...

  6. 30 CFR 75.705-2 - Repairs to energized surface high-voltage lines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Repairs to energized surface high-voltage lines. 75.705-2 Section 75.705-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Grounding § 75.705-2 Repairs to energized surface...

  7. 30 CFR 77.704-2 - Repairs to energized high-voltage lines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Repairs to energized high-voltage lines. 77.704-2 Section 77.704-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Grounding § 77.704-2...

  8. 30 CFR 77.104 - Repair of energized surface high-voltage lines; qualified person.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Repair of energized surface high-voltage lines; qualified person. 77.104 Section 77.104 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL...

  9. 30 CFR 77.704-3 - Work on energized high-voltage surface lines; reporting.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Work on energized high-voltage surface lines; reporting. 77.704-3 Section 77.704-3 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Grounding...

  10. 30 CFR 75.154 - Repair of energized surface high voltage lines; qualified person.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Repair of energized surface high voltage lines; qualified person. 75.154 Section 75.154 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Qualified and Certified Persons § 75.154 Repair...

  11. 30 CFR 77.704 - Work on high-voltage lines; deenergizing and grounding.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Work on high-voltage lines; deenergizing and grounding. 77.704 Section 77.704 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Grounding §...

  12. 30 CFR 77.807-2 - Booms and masts; minimum distance from high-voltage lines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Booms and masts; minimum distance from high-voltage lines. 77.807-2 Section 77.807-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES...

  13. 30 CFR 77.807-3 - Movement of equipment; minimum distance from high-voltage lines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Movement of equipment; minimum distance from high-voltage lines. 77.807-3 Section 77.807-3 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL...

  14. 30 CFR 56.12071 - Movement or operation of equipment near high-voltage power lines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Movement or operation of equipment near high-voltage power lines. 56.12071 Section 56.12071 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Electricity §...

  15. Frequency and voltage dependent profile of dielectric properties, electric modulus and ac electrical conductivity in the PrBaCoO nanofiber capacitors

    NASA Astrophysics Data System (ADS)

    Demirezen, S.; Kaya, A.; Yerişkin, S. A.; Balbaşı, M.; Uslu, İ.

    In this study, praseodymium barium cobalt oxide nanofiber interfacial layer was sandwiched between Au and n-Si. Frequency and voltage dependence of ε‧, ε‧, tanδ, electric modulus (M‧ and M″) and σac of PrBaCoO nanofiber capacitor have been investigated by using impedance spectroscopy method. The obtained experimental results show that the values of ε‧, ε‧, tanδ, M‧, M″ and σac of the PrBaCoO nanofiber capacitor are strongly dependent on frequency of applied bias voltage. The values of ε‧, ε″ and tanδ show a steep decrease with increasing frequency for each forward bias voltage, whereas the values of σac and the electric modulus increase with increasing frequency. The high dispersion in ε‧ and ε″ values at low frequencies may be attributed to the Maxwell-Wagner and space charge polarization. The high values of ε‧ may be due to the interfacial effects within the material, PrBaCoO nanofibers interfacial layer and electron effect. The values of M‧ and M″ reach a maximum constant value corresponding to M∞ ≈ 1/ε∞ due to the relaxation process at high frequencies, but both the values of M‧ and M″ approach almost to zero at low frequencies. The changes in the dielectric and electrical properties with frequency can be also attributed to the existence of Nss and Rs of the capacitors. As a result, the change in the ε‧, ε″, tanδ, M‧, M″ and ac electric conductivity (σac) is a result of restructuring and reordering of charges at the PrBaCoO/n-Si interface under an external electric field or voltage and interface polarization.

  16. Line profile analysis and low temperature AC susceptibility of Cu-Zn ferrites

    SciTech Connect

    Lamani, Ashok. R.; Jayanna, H. S.; Prasanna, G. D.

    2012-06-05

    The Cu{sub 1-x}Zn{sub x}Fe{sub 2}O{sub 4} (x = 0, 0{center_dot}2, 0{center_dot}4, 0{center_dot}6, 0{center_dot}8, 1.0) samples were prepared using double sintering ceramic method by adding Zn{sup 2+} at different concentration. The X-ray line profile analysis were carried out to confirm the spinel phase formation as well as to know the (%) strain in the crystal. The real and imaginary part of a.c. susceptibility measured from 77K to room temperature. The high temperature peak corresponds to magnetic blocking of individual particles, while the low temperature peak is attributed to surface spin-glass freezing. To prove the dynamics of the spin (dis)order in both regimes of freezing and blocking, the frequency dependent ac susceptibility is investigated under a biasing dc field. The frequency shift in the ''frozen'' low-temperature ac susceptibility peak is fitted to a dynamic scaling law which indicates a spin-glass phase. Exchange bias is turned on at low temperature which signifies the existence of a strong core-shell interaction.

  17. Identification and characterization of populations living near high-voltage transmission lines: a pilot study.

    PubMed Central

    Wartenberg, D; Greenberg, M; Lathrop, R

    1993-01-01

    Populations living close to high-voltage transmission lines often have residential magnetic field exposures in excess of 1 microT, and sometimes over 2 microT. Yet, populations studied in most epidemiologic investigations of the association between residential magnetic field exposure and cancer typically have exposures below 1 microT and frequently below 0.5 microT. To improve statistical power and precision, it would be useful to compare high exposure populations with low exposure populations rather than only studying small differences within low exposure populations. Toward this end, we have developed an automated method for identifying populations living near high-voltage transmission lines. These populations likely have more highly exposed individuals than the population at large. The method uses a geographic information system (GIS) to superimpose digitized transmission line locations on U.S. Census block location data and then extract relevant demographic data. Analysis of data from a pilot study of the populations residing within 100 m of a 29-km segment of one 230-kV line in New Jersey shows that when compared to populations in the surrounding census blocks farther than 100 m from this line, those populations close to the line have similar demographics but differ in terms of perceived housing value variables. We believe that the approach we have developed will enable investigators to rapidly identify and characterize populations living near high-voltage transmission lines on a statewide basis for considering the impact of exposures and for public policy and that these populations also can be used for epidemiologic study. Images p626-a Figure 1. Figure 2. Figure 3. PMID:8143596

  18. Voltages induced on a power distribution line by overhead cloud lightning

    NASA Technical Reports Server (NTRS)

    Yacoub, Ziad; Rubinstein, Marcos; Uman, Martin A.; Thomson, Ewen M.; Medelius, Pedro J.

    1991-01-01

    Voltages induced by overhead cloud lightning on a 448 m open circuited power distribution line and the corresponding north-south component of the lightning magnetic field were simultaneously measured at the NASA Kennedy Space Center during the summer of 1986. The incident electric field was calculated from the measured magnetic field. The electric field was then used as an input to the computer program, EMPLIN, that calculated the voltages at the two ends of the power line. EMPLIN models the frequency domain field/power coupling theory found, for example, in Ianoz et al. The direction of the source, which is also one of the inputs to EMPLIN, was crudely determined from a three station time delay technique. The authors found reasonably good agreement between calculated and measured waveforms.

  19. Comparison of charged nanoparticle concentrations near busy roads and overhead high-voltage power lines.

    PubMed

    Jayaratne, E R; Ling, X; Morawska, L

    2015-09-01

    Overhead high-voltage power lines are known sources of corona ions. These ions rapidly attach to aerosols to form charged particles in the environment. Although the effect of ions and charged particles on human health is largely unknown, much attention has focused on the increasing exposure as a result of the expanding power network in urban residential areas. However, it is not widely known that a large number of charged particles in urban environments originate from motor vehicle emissions. In this study, for the first time, we compare the concentrations of charged nanoparticles near busy roads and overhead power lines. We show that large concentrations of both positive and negative charged nanoparticles are present near busy roadways and that these concentrations commonly exceed those under high-voltage power lines. We estimate that the concentration of charged nanoparticles found near two freeways carrying around 120 vehicles per minute exceeded the corresponding maximum concentrations under two corona-emitting overhead power lines by as much as a factor of 5. The difference was most pronounced when a significant fraction of traffic consisted of heavy-duty diesel vehicles which typically have high particle and charge emission rates.

  20. Comparison of charged nanoparticle concentrations near busy roads and overhead high-voltage power lines.

    PubMed

    Jayaratne, E R; Ling, X; Morawska, L

    2015-09-01

    Overhead high-voltage power lines are known sources of corona ions. These ions rapidly attach to aerosols to form charged particles in the environment. Although the effect of ions and charged particles on human health is largely unknown, much attention has focused on the increasing exposure as a result of the expanding power network in urban residential areas. However, it is not widely known that a large number of charged particles in urban environments originate from motor vehicle emissions. In this study, for the first time, we compare the concentrations of charged nanoparticles near busy roads and overhead power lines. We show that large concentrations of both positive and negative charged nanoparticles are present near busy roadways and that these concentrations commonly exceed those under high-voltage power lines. We estimate that the concentration of charged nanoparticles found near two freeways carrying around 120 vehicles per minute exceeded the corresponding maximum concentrations under two corona-emitting overhead power lines by as much as a factor of 5. The difference was most pronounced when a significant fraction of traffic consisted of heavy-duty diesel vehicles which typically have high particle and charge emission rates. PMID:25917858

  1. Application of Magnetically Insulated Transmission Lines for high current, high voltage electron beam accelerators

    SciTech Connect

    Shope, S.L.; Mazarakis, M.G.; Frost, C.A.; Poukey, J.W.; Turman, B.N.

    1991-01-01

    Self Magnetically Insulated Transmission Lines (MITL) adders have been used successfully in a number of Sandia accelerators such as HELIA, HERMES III, and SABRE. Most recently we used at MITL adder in the RADLAC/SMILE electron beam accelerator to produce high quality, small radius (r{sub {rho}} < 2 cm), 11 to 15 MeV, 50 to 100-kA beams with a small transverse velocity v{perpendicular}/c = {beta}{perpendicular} {le} 0.1. In RADLAC/SMILE, a coaxial MITL passed through the eight, 2 MV vacuum envelopes. The MITL summed the voltages of all eight feeds to a single foilless diode. The experimental results are in good agreement with code simulations. Our success with the MITL technology led us to investigate the application to higher energy accelerator designs. We have a conceptual design for a cavity-fed MITL that sums the voltages from 100 identical, inductively-isolated cavities. Each cavity is a toroidal structure that is driven simultaneously by four 8-ohm pulse-forming lines, providing a 1-MV voltage pulse to each of the 100 cavities. The point design accelerator is 100 MV, 500 kA, with a 30--50 ns FWHM output pulse. 10 refs.

  2. Application of Magnetically Insulated Transmission Lines for high current, high voltage electron beam accelerators

    SciTech Connect

    Shope, S.L.; Mazarakis, M.G.; Frost, C.A.; Poukey, J.W.; Turman, B.N.

    1991-12-31

    Self Magnetically Insulated Transmission Lines (MITL) adders have been used successfully in a number of Sandia accelerators such as HELIA, HERMES III, and SABRE. Most recently we used at MITL adder in the RADLAC/SMILE electron beam accelerator to produce high quality, small radius (r{sub {rho}} < 2 cm), 11 to 15 MeV, 50 to 100-kA beams with a small transverse velocity v{perpendicular}/c = {beta}{perpendicular} {le} 0.1. In RADLAC/SMILE, a coaxial MITL passed through the eight, 2 MV vacuum envelopes. The MITL summed the voltages of all eight feeds to a single foilless diode. The experimental results are in good agreement with code simulations. Our success with the MITL technology led us to investigate the application to higher energy accelerator designs. We have a conceptual design for a cavity-fed MITL that sums the voltages from 100 identical, inductively-isolated cavities. Each cavity is a toroidal structure that is driven simultaneously by four 8-ohm pulse-forming lines, providing a 1-MV voltage pulse to each of the 100 cavities. The point design accelerator is 100 MV, 500 kA, with a 30--50 ns FWHM output pulse. 10 refs.

  3. Increase in the scattering of electric field lines in a new high voltage SOI MESFET

    NASA Astrophysics Data System (ADS)

    Anvarifard, Mohammad K.

    2016-09-01

    This paper illustrates a new efficient technique to enhance the critical features of a silicon-on-insulator metal-semiconductor field-effect transistor (SOI MESFET) applied in high voltage applications. The structure we proposed utilizes a new method to scatter the electric field lines along the channel region. Realization of two trenches with different materials, which a trench is created in the channel region and the other one is created in the buried oxide, helps the proposed structure to improve the breakdown voltage, driving current, drain-source conductance, minimum noise figure, unilateral power gain and output power density. Exploring the obtained results, the proposed structure has superior electrical performance in comparison to the conventional structure.

  4. Frequency and voltage dependence dielectric properties, ac electrical conductivity and electric modulus profiles in Al/Co3O4-PVA/p-Si structures

    NASA Astrophysics Data System (ADS)

    Bilkan, Çiğdem; Azizian-Kalandaragh, Yashar; Altındal, Şemsettin; Shokrani-Havigh, Roya

    2016-11-01

    In this research a simple microwave-assisted method have been used for preparation of cobalt oxide nanostructures. The as-prepared sample has been investigated by UV-vis spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM). On the other hand, frequency and voltage dependence of both the real and imaginary parts of dielectric constants (ε‧, ε″) and electric modulus (M‧ and M″), loss tangent (tanδ), and ac electrical conductivity (σac) values of Al/Co3O4-PVA/p-Si structures were obtained in the wide range of frequency and voltage using capacitance (C) and conductance (G/ω) data at room temperature. The values of ε‧, ε″ and tanδ were found to decrease with increasing frequency almost for each applied bias voltage, but the changes in these parameters become more effective in the depletion region at low frequencies due to the charges at surface states and their relaxation time and polarization effect. While the value of σ is almost constant at low frequency, increases almost as exponentially at high frequency which are corresponding to σdc and σac, respectively. The M‧ and M″ have low values at low frequencies region and then an increase with frequency due to short-range mobility of charge carriers. While the value of M‧ increase with increasing frequency, the value of M″ shows two peak and the peaks positions shifts to higher frequency with increasing applied voltage due to the decrease of the polarization and Nss effects with increasing frequency.

  5. Assumption or Fact? Line-to-Neutral Voltage Expression in an Unbalanced 3-Phase Circuit during Inverter Switching

    ERIC Educational Resources Information Center

    Masrur, M. A.

    2009-01-01

    This paper discusses the situation in a 3-phase motor or any other 3-phase system operating under unbalanced operating conditions caused by an open fault in an inverter switch. A dc voltage source is assumed as the input to the inverter, and under faulty conditions of the inverter switch, the actual voltage applied between the line to neutral…

  6. Association between Exposure to Electromagnetic Fields from High Voltage Transmission Lines and Neurobehavioral Function in Children

    PubMed Central

    Huang, Jiongli; Tang, Tiantong; Hu, Guocheng; Zheng, Jing; Wang, Yuyu; Wang, Qiang; Su, Jing; Zou, Yunfeng; Peng, Xiaowu

    2013-01-01

    Background Evidence for a possible causal relationship between exposure to electromagnetic fields (EMF) emitted by high voltage transmission (HVT) lines and neurobehavioral dysfunction in children is insufficient. The present study aims to investigate the association between EMF exposure from HVT lines and neurobehavioral function in children. Methods Two primary schools were chosen based on monitoring data of ambient electromagnetic radiation. A cross-sectional study with 437 children (9 to 13 years old) was conducted. Exposure to EMF from HVT lines was monitored at each school. Information was collected on possible confounders and relevant exposure predictors using standardized questionnaires. Neurobehavioral function in children was evaluated using established computerized neurobehavioral tests. Data was analyzed using multivariable regression models adjusted for relevant confounders. Results After controlling for potential confounding factors, multivariable regression revealed that children attending a school near 500 kV HVT lines had poorer performance on the computerized neurobehavioral tests for Visual Retention and Pursuit Aiming compared to children attending a school that was not in close proximity to HVT lines. Conclusions The results suggest long-term low-level exposure to EMF from HVT lines might have a negative impact on neurobehavioral function in children. However, because of differences in results only for two of four tests achieved statistical significance and potential limitations, more studies are needed to explore the effects of exposure to extremely low frequency EMF on neurobehavioral function and development in children. PMID:23843999

  7. The commercial development of water repellent coatings for high voltage transmission lines

    SciTech Connect

    Hunter, Scott Robert

    2013-10-01

    The purpose of the Cooperative Research and Development Agreement (CRADA) between UT-Battelle, LLC and Southwire Company was to jointly develop a low cost, commercially viable, water-repellant anti-icing coating system for high voltage transmission lines. Icing of power lines and other structures caused by freezing rain events occurs annually in the United States, and leads to severe and prolonged power outages. These outages cause untold economic and personal distress for many American families and businesses. Researchers at the Department of Energy s Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee have previously developed a set of superhydrophobic coatings with remarkable anti-icing properties that could potentially be sprayed or painted onto high-tension power lines and pylons. These coatings drastically reduce ice accumulation on these structures during freezing rain events. The project involved obtaining technical input, supplies and test high voltage cables from Southwire, along with the joint development of anti-icing coating techniques, which would result in a commercial license agreement between Southwire and ORNL, and potentially other companies requiring water repellent anti-icing coatings.

  8. The commercial development of water repellent coatings for high voltage transmission lines

    SciTech Connect

    Hunter, S. R.; Daniel, A.

    2013-10-31

    The purpose of the Cooperative Research and Development Agreement (CRADA) between UT-Battelle, LLC and Southwire Company was to jointly develop a low cost, commercially viable, water-repellant anti-icing coating system for high voltage transmission lines. Icing of power lines and other structures caused by freezing rain events occurs annually in the United States, and leads to severe and prolonged power outages. These outages cause untold economic and personal distress for many American families and businesses. Researchers at the Department of Energy?s Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee have previously developed a set of superhydrophobic coatings with remarkable anti-icing properties that could potentially be sprayed or painted onto high-tension power lines and pylons. These coatings drastically reduce ice accumulation on these structures during freezing rain events. The project involved obtaining technical input, supplies and test high voltage cables from Southwire, along with the joint development of anti-icing coating techniques, which would result in a commercial license agreement between Southwire and ORNL, and potentially other companies requiring water repellent anti-icing coatings.

  9. Apparatus and Method for Compensating for Process, Voltage, and Temperature Variation of the Time Delay of a Digital Delay Line

    NASA Technical Reports Server (NTRS)

    Seefeldt, James (Inventor); Feng, Xiaoxin (Inventor); Roper, Weston (Inventor)

    2013-01-01

    A process, voltage, and temperature (PVT) compensation circuit and a method of continuously generating a delay measure are provided. The compensation circuit includes two delay lines, each delay line providing a delay output. The two delay lines may each include a number of delay elements, which in turn may include one or more current-starved inverters. The number of delay lines may differ between the two delay lines. The delay outputs are provided to a combining circuit that determines an offset pulse based on the two delay outputs and then averages the voltage of the offset pulse to determine a delay measure. The delay measure may be one or more currents or voltages indicating an amount of PVT compensation to apply to input or output signals of an application circuit, such as a memory-bus driver, dynamic random access memory (DRAM), a synchronous DRAM, a processor or other clocked circuit.

  10. Temperature sensing in high voltage transmission lines using fiber Bragg grating and free-space-optics

    NASA Astrophysics Data System (ADS)

    Floridia, Claudio; Rosolem, Joao B.; Leonardi, Ariovaldo A.; Hortencio, Claudio A.; Fonseca, Romeu F.; Moreira, Rodrigo O. C.; Souza, Giovani C. L.; Melo, Altair L.; Nascimento, Carlos A. M.

    2013-05-01

    In this work we proposed the use of free-space-optics (FSO) to transmit and receive the optical signals from optical fiber placed in ground potential to the FBG fiber optics at high voltage potential, using a pair of optical collimators. The technique evaluation was performed in a prototype for the study of sensitivity to optical alignment and in an external environment using emulated sensing systems for both bus bar and overhead transmission line with real isolator chain. It has been shown that the FSO system allows collimators operate at distances of 500 mm to 2.000 mm. This range of distances is similar to the length of insulator's chain up to 230 kV. It was also shown that the proposed system can be used in real external environment for bus bar temperature monitoring in substations, where, even if the time out of the system is of 45%, with major interruption time of almost 15 hours, the majority of the interruption time was less than 18 minutes long. On the other hand, system has to be improved in order to be used in overhead transmission line. As tested for a real isolator chain the system shown a time out of 80.3%, with significant number of events of interruption acquisition time greater than 150 minutes. It is believed that for overhead power lines, system must be installed in rigid surge arresters or in a line post where it is expected to have similar results as in substation bus bars monitoring.

  11. Scaling behaviors and novel creep motion of ac-driven flux lines in type II superconductor with random point pins

    NASA Astrophysics Data System (ADS)

    Cao, Wei-Ping; Luo, Meng-Bo; Hu, Xiao

    2012-01-01

    We performed Langevin dynamics simulations for the ac-driven flux lines in a type II superconductor with random point-like pinning centers. Scaling properties of flux-line velocity with respect to an instantaneous driving force of small frequency and around the critical dc depinning force are revealed successfully, which provides precise estimates on dynamic critical exponents. From the scaling function, we derive a creep law associated with activation by regular shaking. The effective energy barrier vanishes at the critical dc depinning point in a square-root way when the instantaneous driving force increases. The frequency plays a similar role to temperature in conventional creep motions, but in a nontrivial way governed by the critical exponents. We have also performed systematic finite-size scaling analysis for flux-line velocity in transient processes with dc driving, which provide estimates on critical exponents in good agreement with those derived with ac driving. The scaling law is checked successfully.

  12. Environmental justice: a contrary finding for the case of high-voltage electric power transmission lines.

    PubMed

    Wartenberg, Daniel; Greenberg, Michael R; Harris, Gerald

    2010-05-01

    Environmental justice is the consideration of whether minority and/or lower-income residents in a geographic area are likely to have disproportionately higher exposures to environmental toxins than those living elsewhere. Such situations have been identified for a variety of factors, such as air pollution, hazardous waste, water quality, noise, residential crowding, and housing quality. This study investigates the application of this concept to high-voltage electric power transmission lines (HVTL), which some perceive as a health risk because of the magnetic fields they generate, and also as esthetically unpleasing. We mapped all 345 kV and higher voltage HVTL in New York State and extracted and summarized proximate US Census sociodemographic and housing characteristic data into four categories on the basis of distances from HVTL. Contrary to our expectation, people living within 2000 ft from HVTL were more likely to be exposed to magnetic fields, white, of higher income, more educated and home owners, than those living farther away, particularly in urban areas. Possible explanations for these patterns include the desire for the open space created by the rights-of-way, the preference for new homes/subdivisions that are often located near HVTL, and moving closer to HVTL before EMFs were considered a risk. This study suggests that environmental justice may not apply to all environmental risk factors and that one must be cautious in generalizing. In addition, it shows the utility of geographical information system methodology for summarizing information from extremely large populations, often a challenge in epidemiology.

  13. Protection relay of phase-shifting device with thyristor switch for high voltage power transmission lines

    NASA Astrophysics Data System (ADS)

    Lachugin, V. F.; Panfilov, D. I.; Akhmetov, I. M.; Astashev, M. G.; Shevelev, A. V.

    2014-12-01

    Problems of functioning of differential current protection systems of phase shifting devices (PSD) with mechanically changed coefficient of transformation of shunt transformer are analyzed. Requirements for devices of protection of PSD with thyristor switch are formulated. Based on use of nonlinear models of series-wound and shunt transformers of PSD modes of operation of major protection during PSD, switching to zero load operation and to operation under load and during short circuit operation were studied for testing PSD with failures. Use of the principle of duplicating by devices of differential current protection (with realization of functions of breaking) of failures of separate pares of PSD with thyristor switch was substantiated. To ensure protection sensitivity to the shunt transformer winding short circuit, in particular, to a short circuit that is not implemented in the current differential protection for PSD with mechanical switch, the differential current protection reacting to the amount of primary ampere-turns of high-voltage and low-voltage winding of this transformer was designed. Studies have shown that the use of differential current cutoff instead of overcurrent protection for the shunt transformer wndings allows one to provide the sensitivity during thyristor failure with the formation of a short circuit. The results of simulation mode for the PSD with switch thyristor designed to be installed as switching point of Voskhod-Tatarskaya-Barabinsk 220 kV transmission line point out the efficiency of the developed solutions that ensure reliable functioning of the PSD.

  14. Measurements of induced voltages and currents in a distribution power line and associated atmospheric parameters

    NASA Technical Reports Server (NTRS)

    Santiago-Perez, Julio

    1988-01-01

    The frequency and intensity of thunderstorms around the Kennedy Space Center (KSC) has affected scheduled launch, landing, and other ground operations for many years. In order to protect against and provide safe working facilities, KSC has performed and hosted several studies on lightning phenomena. For the reasons mentioned above, KSC has established the Atmospheric Science Field Laboratory (ASFL). At these facilities KSC launches wire-towing rockets into thunderstorms to trigger natural lightning to the launch site. A program named Rocket Triggered Lightning Program (RTLP) is being conducted at the ASFL. This report calls for two of the experiments conducted in the summer 1988 Rocket Triggered Lightning Program. One experiment suspended an electric field mill over the launching areas from a balloon about 500 meters high to measure the space charges over the launching area. The other was to connect a waveform recorder to a nearby distribution power line to record currents and voltages wave forms induced by natural and triggered lightning.

  15. Power factor control system for AC induction motors

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1977-01-01

    A power factor control system for use with ac induction motors was designed which samples lines voltage and current through the motor and decreases power input to the motor proportional to the detected phase displacement between current and voltage. This system provides, less power to the motor, as it is less loaded.

  16. Critical Length Criterion and the Arc Chain Model for Calculating the Arcing Time of the Secondary Arc Related to AC Transmission Lines

    NASA Astrophysics Data System (ADS)

    Cong, Haoxi; Li, Qingmin; Xing, Jinyuan; Li, Jinsong; Chen, Qiang

    2015-06-01

    The prompt extinction of the secondary arc is critical to the single-phase reclosing of AC transmission lines, including half-wavelength power transmission lines. In this paper, a low-voltage physical experimental platform was established and the motion process of the secondary arc was recorded by a high-speed camera. It was found that the arcing time of the secondary arc rendered a close relationship with its arc length. Through the input and output power energy analysis of the secondary arc, a new critical length criterion for the arcing time was proposed. The arc chain model was then adopted to calculate the arcing time with both the traditional and the proposed critical length criteria, and the simulation results were compared with the experimental data. The study showed that the arcing time calculated from the new critical length criterion gave more accurate results, which can provide a reliable criterion in term of arcing time for modeling and simulation of the secondary arc related with power transmission lines. supported by National Natural Science Foundation of China (Nos. 51277061 and 51420105011)

  17. A novel method for predicting critical flashover (CFO) voltages insulation strength of multiple dielectrics on distribution overhead lines

    SciTech Connect

    Shwehdi, M.H.; Shahzad, F.

    1996-12-31

    Electric utilities are striving to improve the appearance of distribution lines, apply different combinations of insulating components to establish the necessary insulation for such lines, by the use of new insulators and simultaneously reduce lightning outages. The impulse critical flashover (CFO) voltages of many overhead line insulators are determined for single and multiple (porcelain, fiberglass, polymers and wood). Laboratory investigation and studies relating to the evaluation of CFO values of distribution lines for multiple dielectrics were reported. Data used by the industry for transmission lines are not fully applicable to estimate CFO`s for distribution lines. Many engineers concerned with the design or operation of high voltage transmission lines have devised methods to estimate the performance of lightning impulse. There is at the present time no such method available on estimating insulation strengths of multiple dielectrics of distribution lines subjected to impulse CFO. This paper presents a method of estimating the CFO insulation strengths of two and three dielectric combinations used on distribution overhead lines using the developed Extended Multi Curves (EMC). The proper use and evaluation of the insulation level by this novel method has a major influence on the design and cost of distribution line construction, application, also improving the performance of specific line designs.

  18. Environmental justice: a contrary finding for the case of high-voltage electric power transmission lines.

    PubMed

    Wartenberg, Daniel; Greenberg, Michael R; Harris, Gerald

    2010-05-01

    Environmental justice is the consideration of whether minority and/or lower-income residents in a geographic area are likely to have disproportionately higher exposures to environmental toxins than those living elsewhere. Such situations have been identified for a variety of factors, such as air pollution, hazardous waste, water quality, noise, residential crowding, and housing quality. This study investigates the application of this concept to high-voltage electric power transmission lines (HVTL), which some perceive as a health risk because of the magnetic fields they generate, and also as esthetically unpleasing. We mapped all 345 kV and higher voltage HVTL in New York State and extracted and summarized proximate US Census sociodemographic and housing characteristic data into four categories on the basis of distances from HVTL. Contrary to our expectation, people living within 2000 ft from HVTL were more likely to be exposed to magnetic fields, white, of higher income, more educated and home owners, than those living farther away, particularly in urban areas. Possible explanations for these patterns include the desire for the open space created by the rights-of-way, the preference for new homes/subdivisions that are often located near HVTL, and moving closer to HVTL before EMFs were considered a risk. This study suggests that environmental justice may not apply to all environmental risk factors and that one must be cautious in generalizing. In addition, it shows the utility of geographical information system methodology for summarizing information from extremely large populations, often a challenge in epidemiology. PMID:19352413

  19. The EP-4(0) shielding kits: a new approach to protection from induced voltage

    SciTech Connect

    Vorob'ev, A. Yu.; Otmorskii, S. G.; Smekalov, V. V.; Gorozhankina, E. N.; Sosunov, N. N.; Bol'shunov, A. M.

    2011-09-15

    Problems of safety in work on overhead power lines and the overhead railroad ac contact network under induced voltages are considered. The use of additional individual protection systems is proposed to provide protection from electric shock during such work.

  20. An all solid-state high-voltage ns trigger generator based on magnetic pulse compression and transmission line transformer.

    PubMed

    Lin, Jiajin; Yang, Jianhua; Zhang, Jiande; Chen, Xinbing

    2013-09-01

    Innovative design of an all solid-state high-voltage ns trigger generator, based on magnetic pulse compression and transmission line transformer, is presented. The repetitive trigger pulse generator was developed to trigger a 700 kV trigatron, which has been used to pulse a repetitive intense electron beam accelerator with Tesla transformer charged double pulse forming lines (PFLs). Experimental results show that the trigger pulse generator could produce 180 kV 65 ns duration pulses with a rise time of 20 ns. The repetitive trigger pulses have nice uniform in the voltage waveform. The control time jitter is less then 3 ns. Owing to its good stability and low time jitter, the high-voltage trigger generator is an excellent candidate to trigger the repetitive accelerator.

  1. AC resistance measuring instrument

    DOEpatents

    Hof, P.J.

    1983-10-04

    An auto-ranging AC resistance measuring instrument for remote measurement of the resistance of an electrical device or circuit connected to the instrument includes a signal generator which generates an AC excitation signal for application to a load, including the device and the transmission line, a monitoring circuit which provides a digitally encoded signal representing the voltage across the load, and a microprocessor which operates under program control to provide an auto-ranging function by which range resistance is connected in circuit with the load to limit the load voltage to an acceptable range for the instrument, and an auto-compensating function by which compensating capacitance is connected in shunt with the range resistance to compensate for the effects of line capacitance. After the auto-ranging and auto-compensation functions are complete, the microprocessor calculates the resistance of the load from the selected range resistance, the excitation signal, and the load voltage signal, and displays of the measured resistance on a digital display of the instrument. 8 figs.

  2. AC Resistance measuring instrument

    DOEpatents

    Hof, Peter J.

    1983-01-01

    An auto-ranging AC resistance measuring instrument for remote measurement of the resistance of an electrical device or circuit connected to the instrument includes a signal generator which generates an AC excitation signal for application to a load, including the device and the transmission line, a monitoring circuit which provides a digitally encoded signal representing the voltage across the load, and a microprocessor which operates under program control to provide an auto-ranging function by which range resistance is connected in circuit with the load to limit the load voltage to an acceptable range for the instrument, and an auto-compensating function by which compensating capacitance is connected in shunt with the range resistance to compensate for the effects of line capacitance. After the auto-ranging and auto-compensation functions are complete, the microprocessor calculates the resistance of the load from the selected range resistance, the excitation signal, and the load voltage signal, and displays of the measured resistance on a digital display of the instrument.

  3. 29 CFR 1926.1410 - Power line safety (all voltages)-equipment operations closer than the Table A zone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 8 2013-07-01 2013-07-01 false Power line safety (all voltages)-equipment operations... video equipment), equipped with flags or similar high-visibility markings, to prevent electrical contact... November 8, 2013, the following procedure may be substituted for the requirement in (d)(4)(i) of...

  4. 40 CFR 53.55 - Test for effect of variations in power line voltage and ambient temperature.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... measurement adaptor (40 CFR part 50, appendix L, figure L-30) or equivalent adaptor to facilitate measurement... specified in section 6 of 40 CFR part 50, appendix L (if required). (d) Calibration of test measurement... line voltage and ambient temperature. 53.55 Section 53.55 Protection of Environment...

  5. 40 CFR 53.55 - Test for effect of variations in power line voltage and ambient temperature.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... measurement adaptor (40 CFR part 50, appendix L, figure L-30) or equivalent adaptor to facilitate measurement... specified in section 6 of 40 CFR part 50, appendix L (if required). (d) Calibration of test measurement... line voltage and ambient temperature. 53.55 Section 53.55 Protection of Environment...

  6. 40 CFR 53.55 - Test for effect of variations in power line voltage and ambient temperature.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... to exceed 5 minutes. (6) Flow measurement adaptor (40 CFR part 50, appendix L, figure L-30) or.... (9) Teflon sample filter, as specified in section 6 of 40 CFR part 50, appendix L (if required). (d... line voltage and ambient temperature. 53.55 Section 53.55 Protection of Environment...

  7. 40 CFR 53.55 - Test for effect of variations in power line voltage and ambient temperature.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... to exceed 5 minutes. (6) Flow measurement adaptor (40 CFR part 50, appendix L, figure L-30) or.... (9) Teflon sample filter, as specified in section 6 of 40 CFR part 50, appendix L (if required). (d... line voltage and ambient temperature. 53.55 Section 53.55 Protection of Environment...

  8. 40 CFR 53.55 - Test for effect of variations in power line voltage and ambient temperature.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... measurement adaptor (40 CFR part 50, appendix L, figure L-30) or equivalent adaptor to facilitate measurement... specified in section 6 of 40 CFR part 50, appendix L (if required). (d) Calibration of test measurement... line voltage and ambient temperature. 53.55 Section 53.55 Protection of Environment...

  9. Voltage-dependent gating of single gap junction channels in an insect cell line.

    PubMed Central

    Bukauskas, F F; Weingart, R

    1994-01-01

    De novo formation of cell pairs was used to examine the gating properties of single gap junction channels. Two separate cells of an insect cell line (clone C6/36, derived from the mosquito Aedes albopictus) were pushed against each other to provoke formation of gap junction channels. A dual voltage-clamp method was used to control the voltage gradient between the cells (Vj) and measure the intercellular current (Ij). The first sign of channel activity was apparent 4.7 min after cell contact. Steady-state coupling reached after 30 min revealed a conductance of 8.7 nS. Channel formation involved no leak between the intra- and extracellular space. The first opening of a newly formed channel was slow (25-28 ms). Each preparation passed through a phase with only one operational gap junction channel. This period was exploited to examine the single channel properties. We found that single channels exhibit several conductance states with different conductances gamma j; a fully open state (gamma j(main state)), several substates (gamma j(substates)), a residual state (gamma j(residual)) and a closed state (gamma j(closed)). The gamma j(main state) was 375 pS, and gamma j(residual) ranged from 30 to 90 pS. The transitions between adjacent substates were 1/7-1/4 of gamma j(main state). Vj had no effect on gamma j(main state), but slightly affected gamma j (residual). The lj transitions involving gamma j(closed) were slow (15-60 ms), whereas those not involving gamma j(closed) were fast (< 2 ms). An increase in Vj led to a decrease in open channel probability. Depolarization of the membrane potential (Vm) increased the incidence of slow transitions leading to gamma j(closed). We conclude that insect gap junctions possess two gates, a fast gate controlled by Vj and giving rise to gamma j(substates) and gamma j(residual), and a slow gate sensitive to Vm and able to close the channel completely. PMID:7524710

  10. Non-Antithrombotic Medical Options in ACS: Old Agents and New Lines on the Horizon

    PubMed Central

    Soukoulis, Victor; Boden, William E.; Smith, Sidney C.; O'Gara, Patrick T.

    2014-01-01

    Acute coronary syndromes (ACS) constitute a spectrum of clinical presentations ranging from unstable angina and non-ST-segment elevation myocardial infarction to ST-segment myocardial infarction. Myocardial ischemia in this context occurs as a result of an abrupt decrease in coronary blood flow and resultant imbalance in the myocardial oxygen supply-demand relationship. Coronary blood flow is further compromised by other mechanisms that increase coronary vascular resistance or reduce coronary driving pressure. The goals of treatment are to decrease myocardial oxygen demand, increase coronary blood flow and oxygen supply, and limit myocardial injury. Treatments are generally divided into “disease-modifying” agents or interventions that improve hard clinical outcomes and other strategies that can reduce ischemia. In addition to traditional drugs such as beta-blockers and inhibitors of the reninangiotensin-aldosterone system, newer agents have expanded the number of molecular pathways targeted for treatment of ACS. Ranolazine, trimetazidine, nicorandil, and ivabradine are medications that have been shown to reduce myocardial ischemia through diverse mechanisms and have been tested in limited fashion in patients with ACS. Attenuating the no-reflow phenomenon and reducing the injury compounded by acute reperfusion after a period of coronary occlusion are active areas of research. Additionally, interventions aimed at ischemic pre- and post-conditioning may be useful means by which to limit myocardial infarct size. Trials are also underway to examine altered metabolic and oxygen-related pathways in ACS. This review will discuss traditional and newer anti-ischemic therapies for patients with ACS, exclusive of revascularization, anti-thrombotic agents, and the use of high-intensity statins. PMID:24902977

  11. Asymmetric synthesis of crambescin A-C carboxylic acids and their inhibitory activity on voltage-gated sodium channels.

    PubMed

    Nakazaki, Atsuo; Nakane, Yoshiki; Ishikawa, Yuki; Yotsu-Yamashita, Mari; Nishikawa, Toshio

    2016-06-21

    Synthesis of both enantiomers of crambescin B carboxylic acid is described. A cis-enyne starting material was epoxidized under the conditions of Katsuki asymmetric epoxidation to give 95% ee of the epoxide, which was transformed to crambescin B carboxylic acid via bromocation-triggered cascade cyclization as the key step. Enantiomerically pure crambescin A and C carboxylic acids were also synthesized from the product of the cascade reaction. Structure-activity relationship (SAR) studies against voltage-gated sodium channel (VGSC) inhibition using those synthetic compounds revealed that the natural enantiomer of crambescin B carboxylic acid was most active and comparable to tetrodotoxin, and the unalkylated cyclic guanidinium structure is indispensible, while the carboxylate moiety is not important. The absolute stereochemistry of crambescin A was determined by a comparison of the methyl ester derived from natural crambescin A with that derived from the stereochemically defined crambescin A carboxylic acid synthesized in this study.

  12. The monitoring results of electromagnetic radiation of 110-kV high-voltage lines in one urban location in Chongqing P.R. China.

    PubMed

    Qin, Qi-Zhong; Chen, Yu; Fu, Ting-Ting; Ding, Li; Han, Ling-Li; Li, Jian-Chao

    2012-03-01

    To understand electromagnetic radiation field strength and its influencing factors of certain 110-kV high-voltage lines in one urban area of Chongqing by measuring 110-kV high-voltage line's electromagnetic radiation level. According to the methodology as determined by the National Hygienic Standards, we selected certain adjacent residential buildings, high-voltage lines along a specific street and selected different distances around its vertical projection point as monitoring points. The levels of electromagnetic radiations were measured respectively. In this investigation within the frequency of 5-1,000 Hz both the electric field strength and magnetic field strength of each monitoring sites were lower than the public exposure standards as determined by the International Commission on Non-Ionizing Radiation Protection. However, the electrical field strength on the roof adjacent to the high-voltage lines was significantly higher than that as measured on the other floors in the same buildings (p < 0.05). The electromagnetic radiation measurements of different monitoring points, under the same high-voltage lines, showed the location which is nearer the high-voltage line maintain a consistently higher level of radiation than the more distant locations (p < 0.05). Electromagnetic radiation generated by high-voltage lines decreases proportionally to the distance from the lines. The buildings can to some extent shield (or absorb) the electric fields generated by high-voltage lines nearby. The electromagnetic radiation intensity near high-voltage lines may be mitigated or intensified by the manner in which the high-voltage lines are set up, and it merits attention for the potential impact on human health.

  13. Effects of dietary green tea polyphenol supplementation on the health of workers exposed to high-voltage power lines.

    PubMed

    Zhang, Yang; Zhang, Dan; Zhu, Baoyu; Zhang, He; Sun, Ye; Sun, Chengxun

    2016-09-01

    Although it has been several decades since the focus on the effect of extremely low frequency electromagnetic fields (ELF-EMF) of high-voltage power lines on human health, no consistent conclusion has been drawn. The present study aimed to investigate the change in oxidative stress after exposure to ELF-EMFs, and potential protective effects of green tea polyphenol supplementation (GTPS) on ELF-EMFs induced oxidative stress. A total of 867 subjects, including workers with or without exposure to ELF-EMFs of 110-420kV power lines, participated and were randomized into GTPS and placebo treatment groups. Oxidative stress and oxidative damage to DNA were assessed by urinary tests of 8-isoprostane and 8-OHdG. Significant increased urinary 8-isoprostane and 8-OHdG were observed in workers with ELF-EMFs exposure, which were diminished after 12 months of GTPS. No protective effects of GTPS on oxidative stress and oxidative damage to DNA were observed after three months of GTPS withdraw. We found a negative impact of high-voltage power lines on the health of workers. Long-term GTPS could be an efficient protection against the health issues induced by high-voltage power lines. PMID:27490209

  14. Effects of dietary green tea polyphenol supplementation on the health of workers exposed to high-voltage power lines.

    PubMed

    Zhang, Yang; Zhang, Dan; Zhu, Baoyu; Zhang, He; Sun, Ye; Sun, Chengxun

    2016-09-01

    Although it has been several decades since the focus on the effect of extremely low frequency electromagnetic fields (ELF-EMF) of high-voltage power lines on human health, no consistent conclusion has been drawn. The present study aimed to investigate the change in oxidative stress after exposure to ELF-EMFs, and potential protective effects of green tea polyphenol supplementation (GTPS) on ELF-EMFs induced oxidative stress. A total of 867 subjects, including workers with or without exposure to ELF-EMFs of 110-420kV power lines, participated and were randomized into GTPS and placebo treatment groups. Oxidative stress and oxidative damage to DNA were assessed by urinary tests of 8-isoprostane and 8-OHdG. Significant increased urinary 8-isoprostane and 8-OHdG were observed in workers with ELF-EMFs exposure, which were diminished after 12 months of GTPS. No protective effects of GTPS on oxidative stress and oxidative damage to DNA were observed after three months of GTPS withdraw. We found a negative impact of high-voltage power lines on the health of workers. Long-term GTPS could be an efficient protection against the health issues induced by high-voltage power lines.

  15. Single and three-phase AC losses in HTS superconducting power transmission line prototype cables

    SciTech Connect

    Daney, D.E.; Boenig, H.J.; Maley, M.P.; Coulter, J.Y.; Fleshler, S.

    1997-11-01

    AC losses in two, one-meter-long lengths of HTS prototype multi-strand conductors (PMC`s) are measured with a temperature-difference calorimeter. Both single-phase and three-phase losses are examined with ac currents up to 1,000 A rms. The calorimeter, designed specifically for these measurements, has a precision of 1 mW. PMC {number_sign}1 has two helically-wound, non-insulated layers of HTS tape (19 tapes per layer), each layer wrapped with opposite pitch. PMC {number_sign}2 is identical except for insulation between the layers. The measured ac losses show no significant effect of interlayer insulation and depend on about the third power of the current--a result in agreement with the Bean-Norris model adapted to the double-helix configuration. The three-phase losses are a factor of two higher than those exhibited by a single isolated conductor, indicating a significant interaction between phases.

  16. Development of Voltage Regulation Plan by Composing Subsystem with the SFES for DC On-line Electric Vehicle

    NASA Astrophysics Data System (ADS)

    Jung, S.; Lee, J. H.; Yoon, M.; Lee, H.; Jang, G.

    The study of the application process of the relatively small size 'Superconducting Flywheel Energy Storage (SFES)' system is conducted to regulate voltage fluctuation of the DC On-Line Electric Vehicle (OLEV) system, which is designed by using DC power system network. It is recommended to construct the power conversion system nearby the substation because the charging system is under the low voltage. But as the system is usually built around urban area and it makes hard to construct the subsystems at every station, voltage drop can occur in power supply inverter that is some distance from the substation. As the alternative of this issue, DC distribution system is recently introduced and has possibility to solve the above issue. In this paper, SFES is introduced to solve the voltage drop under the low voltage distribution system by using the concept of the proposed DC OLEV which results in building the longer distance power supply system. The simulation to design the SFES by using DC power flow analysis is carried out and it is verified in this paper.

  17. Project resumes: biological effects from electric fields associated with high-voltage transmission lines

    SciTech Connect

    1980-01-01

    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)

  18. High-voltage isolation transformer for sub-nanosecond rise time pulses constructed with annular parallel-strip transmission lines.

    PubMed

    Homma, Akira

    2011-07-01

    A novel annular parallel-strip transmission line was devised to construct high-voltage high-speed pulse isolation transformers. The transmission lines can easily realize stable high-voltage operation and good impedance matching between primary and secondary circuits. The time constant for the step response of the transformer was calculated by introducing a simple low-frequency equivalent circuit model. Results show that the relation between the time constant and low-cut-off frequency of the transformer conforms to the theory of the general first-order linear time-invariant system. Results also show that the test transformer composed of the new transmission lines can transmit about 600 ps rise time pulses across the dc potential difference of more than 150 kV with insertion loss of -2.5 dB. The measured effective time constant of 12 ns agreed exactly with the theoretically predicted value. For practical applications involving the delivery of synchronized trigger signals to a dc high-voltage electron gun station, the transformer described in this paper exhibited advantages over methods using fiber optic cables for the signal transfer system. This transformer has no jitter or breakdown problems that invariably occur in active circuit components.

  19. An On-Chip Noise Canceller with High Voltage Supply Lines for Nanosecond-Range Power Supply Noise

    NASA Astrophysics Data System (ADS)

    Nakamura, Yasumi; Takamiya, Makoto; Sakurai, Takayasu

    An on-chip power supply noise canceller with higher voltage supply and switching transistor is proposed and the effectiveness of the canceller is experimentally verified. The noise canceller is effective for nano-second order noise caused by circuit wakeup or step increase of frequency in frequency hopping. The principle of the noise canceller is to reduce the current flowing through the supply line of VDD by injecting additional current from the higher voltage supply, so that the voltage drop across the VDD supply line is reduced. As additional current flow from higher supply, switching transistor has to be turned off not to increase the power consumption. With turn-off time of 2L/R, this current can be turned off without inducting another droop due to the increase of current flowing through the power supply line. The measurement shows the canceller reduces 68% of the noise with load circuit equivalent to 530k logic gates in 90-nm CMOS with 9% wire overhead, 1.5% area overhead, and 3% power overhead at 50k wake-ups/s. Compared to passive noise reduction, proposed noise canceller reduces power supply noise by 64% without wire overhead and to achieve same noise reduction with passive method, 77 times more C or 45 times less L is required. Too large switching transistor results in saturated noise reduction effect and higher power consumption. A rule-of-thumb is to set the on-resistance to supply 100% of load current when turned-on.

  20. Improving the output voltage waveform of an intense electron-beam accelerator based on helical type Blumlein pulse forming line

    NASA Astrophysics Data System (ADS)

    Cheng, Xin-Bing; Liu, Jin-Liang; Zhang, Hong-Bo; Feng, Jia-Huai; Qian, Bao-Liang

    2010-07-01

    The Blumlein pulse forming line (BPFL) consisting of an inner coaxial pulse forming line (PFL) and an outer coaxial PFL is widely used in the field of pulsed power, especially for intense electron-beam accelerators (IEBA). The output voltage waveform determines the quality and characteristics of the output beam current of the IEBA. Comparing with the conventional BPFL, an IEBA based on a helical type BPFL can increase the duration of the output voltage in the same geometrical volume. However, for the helical type BPFL, the voltage waveform on a matched load may be distorted which influences the electron-beam quality. In this paper, an IEBA based on helical type BPFL is studied theoretically. Based on telegrapher equations of the BPFL, a formula for the output voltage of IEBA is obtained when the transition section is taken into account, where the transition section is between the middle cylinder of BPFL and the load. From the theoretical analysis, it is found that the wave impedance and transit time of the transition section influence considerably the main pulse voltage waveform at the load, a step is formed in front of the main pulse, and a sharp spike is also formed at the end of the main pulse. In order to get a well-shaped square waveform at the load and to improve the electron-beam quality of such an accelerator, the wave impedance of the transition section should be equal to that of the inner PFL of helical type BPFL and the transit time of the transition section should be designed as short as possible. Experiments performed on an IEBA with the helical type BPFL show reasonable agreement with theoretical analysis.

  1. VOLTAGE REGULATOR

    DOEpatents

    Von Eschen, R.L.; Scheele, P.F.

    1962-04-24

    A transistorized voltage regulator which provides very close voitage regulation up to about 180 deg F is described. A diode in the positive line provides a constant voltage drop from the input to a regulating transistor emitter. An amplifier is coupled to the positive line through a resistor and is connected between a difference circuit and the regulating transistor base which is negative due to the difference in voltage drop across thc diode and the resistor so that a change in the regulator output causes the amplifier to increase or decrease the base voltage and current and incrcase or decrease the transistor impedance to return the regulator output to normal. (AEC)

  2. Ion diode performance on a positive polarity inductive voltage adder with layered magnetically insulated transmission line flow

    SciTech Connect

    Hinshelwood, D. D.; Schumer, J. W.; Allen, R. J.; Commisso, R. J.; Jackson, S. L.; Murphy, D. P.; Phipps, D.; Swanekamp, S. B.; Weber, B. V.; Ottinger, P. F.; Apruzese, J. P.; Cooperstein, G.; Young, F. C.

    2011-05-15

    A pinch-reflex ion diode is fielded on the pulsed-power machine Mercury (R. J. Allen, et al., 15th IEEE Intl. Pulsed Power Conf., Monterey, CA, 2005, p. 339), which has an inductive voltage adder (IVA) architecture and a magnetically insulated transmission line (MITL). Mercury is operated in positive polarity resulting in layered MITL flow as emitted electrons are born at a different potential in each of the adder cavities. The usual method for estimating the voltage by measuring the bound current in the cathode and anode of the MITL is not accurate with layered flow, and the interaction of the MITL flow with a pinched-beam ion diode load has not been studied previously. Other methods for determining the diode voltage are applied, ion diode performance is experimentally characterized and evaluated, and circuit and particle-in-cell (PIC) simulations are performed. Results indicate that the ion diode couples efficiently to the machine operating at a diode voltage of about 3.5 MV and a total current of about 325 kA, with an ion current of about 70 kA of which about 60 kA is proton current. It is also found that the layered flow impedance of the MITL is about half the vacuum impedance.

  3. A differential line protection scheme for power systems based on composite voltage and current measurements

    SciTech Connect

    Aggarwal, R.K.; Johns, A.T.

    1989-07-01

    A differential feeder protection scheme that utilizes voltage and current signals is described. This approach obviates the need for relay bias to compensate for capacitance spill current, thus improving the relay sensitivity. From a practical point of view, the scheme has been designed to simplify the digital hardware requirements and reduce the bandwidth requirements for signal transmission over a fibre optic link.

  4. Electrical Experiments. VT-214-12-2. Part II. A-C Across the Line Control.

    ERIC Educational Resources Information Center

    Connecticut State Dept. of Education, Hartford. Div. of Vocational Education.

    Designed for high school electronics students, this second document in a series of six electrical learning activity packages focuses on alternating current across-the-line control. An introductory section gives the objective for the activities, an introduction, and an outline of the content. The remainder of the activity book is comprised of…

  5. Optical sensing in high voltage transmission lines using power over fiber and free space optics

    NASA Astrophysics Data System (ADS)

    Rosolem, João Batista; Bassan, Fabio Renato; Penze, Rivael Strobel; Leonardi, Ariovaldo Antonio; Fracarolli, João Paulo Vicentini; Floridia, Claudio

    2015-12-01

    In this work we propose the use of power over fiber (PoF) and free space optics (FSO) techniques to powering and receive signals from an electrical current sensor placed at high voltage potential using a pair of optical collimators. The technique evaluation was performed in a laboratorial prototype using 62.5/125 μm multimode fiber to study the sensitivity of the optical alignment and the influence of the collimation process in the sensing system wavelengths: data communication (1310 nm) and powering (830 nm). The collimators were installed in a rigid electric insulator in order to maintain the stability of transmission.

  6. 30 CFR 75.705-2 - Repairs to energized surface high-voltage lines.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Grounding § 75.705-2... with the use of live line tools; (4) Weather conditions will not interfere with such repairs or...

  7. 30 CFR 75.705-2 - Repairs to energized surface high-voltage lines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Grounding § 75.705-2... with the use of live line tools; (4) Weather conditions will not interfere with such repairs or...

  8. 30 CFR 75.705-2 - Repairs to energized surface high-voltage lines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Grounding § 75.705-2... with the use of live line tools; (4) Weather conditions will not interfere with such repairs or...

  9. Transmission line pulse properties for a bidirectional transient voltage suppression diode fabricated using low-temperature epitaxy

    NASA Astrophysics Data System (ADS)

    Bouangeune, Daoheung; Cho, Deok-Ho; Yun, Hyung-Joong; Shim, Kyu-Hwan; Choi, Chel-Jong

    2015-01-01

    Based on low temperature epitaxy technology, a bidirectional transient voltage suppression (TVS) diode with abrupt multi-junctions was developed. The bidirectional triggering voltage of ±16 V was controlled by the thickness and dopant concentration in the multi-junctions using a reduced-pressure chemical vapor deposition (RPCVD) process. The manufactured TVS diode showed a small leakage current density and dynamic resistance of less than 5.1 × 10-14 A/ µm2 and 1 O, respectively, which could be associated with the epitaxially grown abrupt multijunctions. The transmission line pulse (TLP) analysis results demonstrated that the bidirectional TVS diodes were capable of withstanding a peak pulse current of up to ±20 A or ±1.02 × 10-3 A/ µm2, which is equivalent to ±40 kV of the human body model (HBM) and ±12 kV of IEC61000-4-2 (IEC). Nevertheless, the electrostatic discharge (ESD) design window showed that bidirectional TVS diodes meet IEC level 4 standard ESD protection requirements (8 kV in contact discharge). In addition, because of the bidirectional structure, the TVS devices exhibited a small capacitance of 4.9 pF, which confirms that the TVS diode can be used for protecting high data rate communication lines (over 500 Mbps) from ESD shock.

  10. An Approach to the Lightning Overvoltage Protection of Medium Voltage Lines in Severe Lightning Areas

    SciTech Connect

    Omidiora, M. A.; Lehtonen, M.

    2008-05-08

    This paper deals with the effect of shield wires on lightning overvoltage reduction and the energy relief of MOV (Metal Oxide Varistor) arresters from direct strokes to distribution lines. The subject of discussion is the enhancement of lightning protection in Finnish distribution networks where lightning is most severe. The true index of lightning severity in these areas is based on the ground flash densities and return stroke data collected from the Finnish meteorological institute. The presented test case is the IEEE 34-node test feeder injected with multiple lightning strokes and simulated with the Alternative Transients Program/Electromagnetic Transients program (ATP/EMTP). The response of the distribution line to lightning strokes was modeled with three different cases: no protection, protection with surge arresters and protection with a combination of shield wire and arresters. Simulations were made to compare the resulting overvoltages on the line for all the analyzed cases.

  11. 76 FR 26183 - Safety Zone; Repair of High Voltage Transmission Lines to Logan International Airport, Saugus...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-06

    ... to Logan International Airport, Saugus River, Saugus, MA AGENCY: Coast Guard, DHS. ACTION: Temporary... Lines to Logan International Airport, Saugus River, Saugus, Massachusetts, in the Federal Register (76 FR 4575-4577). We received no comments on the proposed rule. No public meeting was requested,...

  12. On-line solid-phase extraction LC-MS/MS for the determination of Ac-SDKP peptide in human plasma from hemodialysis patients.

    PubMed

    Inoue, Koichi; Ikemura, Ayaka; Tsuruta, Yoshinari; Tsutsumiuchi, Kaname; Hino, Tomoaki; Oka, Hisao

    2012-02-01

    We developed a high-throughput method based on on-line solid-phase extraction liquid chromatography tandem mass spectrometry (SPE-LC-MS/MS) to determine N-terminal thymosin-β fragment peptide (N-acetyl-seryl-aspartyl-lysyl-proline, Ac-SDKP) in human plasma samples. Quantification of Ac-SDKP was performed using direct injection for on-line SPE based on C(18), reversed-phase LC separation and stable isotope dilution electrospray ionization-MS/MS in multiple reaction-monitoring (MRM) mode. The Ac-SDKP-(13)C(6), (15)N(2) (m/z 496 → 137) was synthesized for the internal standard. The MRM ion for Ac-SDKP was m/z 488 → 129 (quantitative ion)/226. The limit of detection and lower limit of quantitation were 0.05 and 0.1 ng/mL in standard solution, respectively. Recovery values were 98.3-100.4% with inter-day (relative standard deviation, RSD, 0.4-14.1%) and intra-day (RSD, 0.8-19.7%) assays. This method was applied to the measurement of Ac-SDKP levels in plasma from hemodialyzed subjects. Concentrations were 0.59 ± 0.23 ng/mL (pre-hemodialyzed subjects, n = 9) and 0.44 ± 0.19 ng/mL (post-hemodialyzed subjects, n = 9). All plasma Ac-SDKP levels were decreased by dialysis. Thus, plasma Ac-SDKP was decreased through dialysis in chronic kidney disease. The findings in this study will be useful for the treatment of anemia in chronic kidney disease with dialysis.

  13. Correction: BTI-Tnao38, a new cell line derived from Trichoplusia ni, is permissive for AcMNPV infection and produces high levels of recombinant proteins

    PubMed Central

    2012-01-01

    After publication we discovered an error in the identification of the origin of the cell line reported in our article in BMC Biotechnology (2010, 10:50), entitled "Ao38, a new cell line from eggs of the black witch moth, Ascalapha odorata (Lepidoptera: Noctuidae), is permissive for AcMNPV infection and produces high levels of recombinant proteins". Upon analysis of primary A. odorata cultures, we found that they were contaminated with cells of Trichoplusia ni origin. The origin of the Ao38 cell line was determined as T. ni using three marker genes and the Ao38 cell line was renamed BTI-Tnao38. References to the origin of the cell line as Ascalapha odorata should be replaced with "a cell line of Trichoplusia ni origin". The absence of TNCL virus detection in the BTI-Tnao38 (Ao38) cell line was confirmed using a highly sensitive RT-PCR protocol capable of detecting TNCL virus RNA at approximately 0.018 copies/cell. Because of these observations, we have revised the title of the original article to "Correction: BTI-Tnao38, a new cell line derived from Trichoplusia ni, is permissive for AcMNPV infection and produces high levels of recombinant proteins" and two additional authors were added to reflect their contributions to the analysis of this cell line. PMID:22531032

  14. Extra-high voltage transmission lines: mechanisms of biological effects on honeybees. Final report

    SciTech Connect

    Greenberg, B.; Bindokas, V.

    1985-08-01

    The authors confirmed that bee exposure to E fields, including 100 kV/m, under the dry conditions cause no detectable effect on colony behavior. If, however, exposure occurs when moisture is present, or if bees are on a conductive surface, they become visibly disturbed, mortality is increased, abnormal propolization occurs, and colony development may be impaired. It seems plausible that bees on conductive surfaces within a hive under a 765-kV/m transmission line can perceive shocks from body currents induced by enhanced intra-hive E fields. Hives exposed under a 765-kV/m transmission line to an ambient E field of 7 kV/m have internal step-potential-induced currents and interchamber chort-circuit currents which range from one-half to several microamperes. Total hive currents can exceed 100 ..mu..A. Thus, induced hive currents exceed the empirical sting threshold by up to a factor of 100 and the E-field-induced body current by up to a factor of 1000. The degree of disturbance which could be produced by these intra-hive currents will eclipse that produced by perception of E-field-induced body currents. The authors therefore attribute the disturbance of colonies under a transmission line primarily to electric shock from induced hive currents. 10 refs., 51 figs., 18 tabs. (DT)

  15. Fiber Bragg grating sensor for fault detection in high voltage overhead transmission lines

    NASA Astrophysics Data System (ADS)

    Moghadas, Amin

    2011-12-01

    A fiber optic based sensor capable of fault detection in both radial and network overhead transmission power line systems is investigated. Bragg wavelength shift is used to measure the fault current and detect fault in power systems. Magnetic fields generated by currents in the overhead transmission lines cause a strain in magnetostrictive material which is then detected by fiber Bragg grating (FBG) sensors. The Fiber Bragg interrogator senses the reflected FBG signals, and the Bragg wavelength shift is calculated and the signals are processed. A broadband light source in the control room scans the shift in the reflected signals. Any surge in the magnetic field relates to an increased fault current at a certain location. Also, fault location can be precisely defined with an artificial neural network (ANN) algorithm. This algorithm can be easily coordinated with other protective devices. It is shown that the faults in the overhead transmission line cause a detectable wavelength shift on the reflected signal of FBG sensors and can be used to detect and classify different kind of faults. The proposed method has been extensively tested by simulation and results confirm that the proposed scheme is able to detect different kinds of fault in both radial and network system.

  16. Carbon Nanotube-Based Supercapacitors with Excellent ac Line Filtering and Rate Capability via Improved Interfacial Impedance.

    PubMed

    Rangom, Yverick; Tang, Xiaowu Shirley; Nazar, Linda F

    2015-07-28

    We report the fabrication of high-performance, self-standing composite sp(2)-carbon supercapacitor electrodes using single-walled carbon nanotubes (CNTs) as conductive binder. The 3-D mesoporous mesh architecture of CNT-based composite electrodes grants unimpaired ionic transport throughout relatively thick films and allows superior performance compared to graphene-based devices at an ac line frequency of 120 Hz. Metrics of 601 μF/cm(2) with a -81° phase angle and a rate capability (RC) time constant of 199 μs are obtained for thin carbon films. The free-standing carbon films were obtained from a chlorosulfonic acid dispersion and interfaced to stainless steel current collectors with various surface treatments. CNT electrodes were able to cycle at 200 V/s and beyond, still showing a characteristic parallelepipedic cyclic votammetry shape at 1 kV/s. Current densities are measured in excess of 6400 A/g, and the electrodes retain more than 98% capacity after 1 million cycles. These promising results are attributed to a reduction of series resistance in the film through the CNT conductive network and especially to the surface treatment of the stainless steel current collector. PMID:26046685

  17. Carbon Nanotube-Based Supercapacitors with Excellent ac Line Filtering and Rate Capability via Improved Interfacial Impedance.

    PubMed

    Rangom, Yverick; Tang, Xiaowu Shirley; Nazar, Linda F

    2015-07-28

    We report the fabrication of high-performance, self-standing composite sp(2)-carbon supercapacitor electrodes using single-walled carbon nanotubes (CNTs) as conductive binder. The 3-D mesoporous mesh architecture of CNT-based composite electrodes grants unimpaired ionic transport throughout relatively thick films and allows superior performance compared to graphene-based devices at an ac line frequency of 120 Hz. Metrics of 601 μF/cm(2) with a -81° phase angle and a rate capability (RC) time constant of 199 μs are obtained for thin carbon films. The free-standing carbon films were obtained from a chlorosulfonic acid dispersion and interfaced to stainless steel current collectors with various surface treatments. CNT electrodes were able to cycle at 200 V/s and beyond, still showing a characteristic parallelepipedic cyclic votammetry shape at 1 kV/s. Current densities are measured in excess of 6400 A/g, and the electrodes retain more than 98% capacity after 1 million cycles. These promising results are attributed to a reduction of series resistance in the film through the CNT conductive network and especially to the surface treatment of the stainless steel current collector.

  18. Final report on SIM bilateral INMETRO-LNE comparisons SIM.EM-K6.1 and SIM.EM-K9.1: AC-DC voltage transfer difference

    NASA Astrophysics Data System (ADS)

    Vasconcellos, Renata de Barros e.; Poletaeff, Andre

    2014-01-01

    The objective of this comparison was to compare the measurement capabilities of INMETRO and LNE in the field of AC-DC voltage transfer. INMETRO participated in the previous SIM comparison of AC-DC voltage transfer standards in 2004. In the last few years INMETRO has been improving the methodology of its AC-DC voltage transfer difference measurements, now using multijunction thermal converters. The degrees of equivalence of INMETRO relative to the corresponding CCEM key comparison reference values range between 0.1 µV/V and 10 µV/V in the frame of the SIM.EM-K6.1 key comparison, and between 0.5 µV/V and 4 µV/V in the frame of the SIM.EM-K9.1 key comparison. In all cases, they are consistent with the associated uncertainties. For results that are not linked to CCEM key comparisons, the agreement between INMETRO and LNE is very good at 1.5 V/50 kHz (0.1 µV/V). At 10 Hz (at 1.5 V and at 1000 V) a larger difference is observed between the two laboratories, which remains nevertheless consistent with the given uncertainties. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  19. Effects of magnetic fields during high voltage live-line maintenance

    NASA Astrophysics Data System (ADS)

    Göcsei, Gábor; Kiss, István, Dr; Németh, Bálint

    2015-10-01

    In case of transmission and distribution networks, extra low frequency (typically 50 or 60 Hz) electric and magnetic fields have to be taken into consideration separately from each other. Health effects have been documented from exposures to both types of fields. Magnetic fields are qualified as possibly carcinogenic to humans (category “2B”) by WHO's cancer research institute, International Agency for Research on Cancer (IARC), so it is essential to protect the workers against their harmful effects. During live-line maintenance (LLM) electric fields can be shielded effectively by different kinds of conductive clothing, which are enclosed metal surfaces acting as a Faraday-cage. In practice laboratory measurements also prove their efficiency, the required shielding ratio is above 99% by the related standard.. A set of measurements have proved that regular conductive clothing used against the electric fields cannot shield the magnetic fields effectively at all. This paper introduces the possible risks of LLM from the aspect of the health effects of magnetic fields. Although in this case the principle of shielding the electric fields cannot be applied, new considerations in equipment design and technology can be used as a possible solution. Calculations and simulations based on the data of the Hungarian transmission network - which represents the European grid as a part of ENTSO-E - and high-current laboratory measurement results also prove the importance of the topic.

  20. A straightforward electro-optic polymer covered titanium dioxide strip line modulator with a low driving voltage

    NASA Astrophysics Data System (ADS)

    Qiu, Feng; Spring, Andrew M.; Maeda, Daisuke; Ozawa, Masa-aki; Odoi, Keisuke; Aoki, Isao; Otomo, Akira; Yokoyama, Shiyoshi

    2014-08-01

    An electro-optic (EO) modulator composed of an EO polymer/titanium dioxide (TiO2) hybrid waveguide has been designed and fabricated. By using a TiO2 strip line (0.3 × 0.3 μm2 cross-section) as the core, the confinement factor in the EO polymer is optimized, thus achieving a high EO activity. The coplanar electrode spacing is tuned to enable an effective poling and a small propagation loss. The measured in-device EO coefficient is 100 pm/V at 1550 nm, with a driving voltage (Vπ) 3.2 V for the 12 mm-electrode length. The results also predict a possible Vπ of ˜1 V in a push-pull MZI structure. The EO activity of the modulator exhibited an excellent temporal stability at 85 °C for 500 h due to the high glass transition temperature of the EO polymer and the temperature-insensitive TiO2 strip line.

  1. Re-creation of aerosol charge state found near HV power lines using a high voltage corona charger

    NASA Astrophysics Data System (ADS)

    Matthews, J. C.; Wright, M. D.; Biddiscombe, M. F.; Underwood, R.; Usmani, O. S.; Shallcross, D. E.; Henshaw, D. L.

    2015-10-01

    Corona ionisation from AC HV power lines (HVPL) can release ions into the environment, which have the potential to electrically charge pollutant aerosol in the atmosphere. It has been hypothesised that these charged particles have an enhanced probability of being deposited in human airways upon inhalation due to electrostatic attraction by image charge within the lung, with implications for human health. Carbonaceous aerosol particles from a Technegas generator were artificially charge-enhanced using a corona charger. Once generated, particles were passed through the charger, which was either on or off, and stored in a 15 litre conducting bag for ∼20 minutes to observe size and charge distribution changes over time. Charge states were estimated using two Sequential Mobility Particle Sizers measuring the size and mobility distributions. Charge-neutral particles were measured 7 times and positive particles 9 times, the average charge-neutral value of x was 1.00 (sd = 0.06) while the average positive value was 4.60 (0.72). The system will be used to generate positive or charge neutral particles for delivery to human volunteers in an inhalation study to assess the impact of charge on ultrafine (size < 100 nm) particle deposition.

  2. Application of HFCT and UHF sensors in on-line partial discharge measurements for insulation diagnosis of high voltage equipment.

    PubMed

    Álvarez, Fernando; Garnacho, Fernando; Ortego, Javier; Sánchez-Urán, Miguel Ángel

    2015-01-01

    Partial discharge (PD) measurements provide valuable information for assessing the condition of high voltage (HV) insulation systems, contributing to their quality assurance. Different PD measuring techniques have been developed in the last years specially designed to perform on-line measurements. Non-conventional PD methods operating in high frequency bands are usually used when this type of tests are carried out. In PD measurements the signal acquisition, the subsequent signal processing and the capability to obtain an accurate diagnosis are conditioned by the selection of a suitable detection technique and by the implementation of effective signal processing tools. This paper proposes an optimized electromagnetic detection method based on the combined use of wideband PD sensors for measurements performed in the HF and UHF frequency ranges, together with the implementation of powerful processing tools. The effectiveness of the measuring techniques proposed is demonstrated through an example, where several PD sources are measured simultaneously in a HV installation consisting of a cable system connected by a plug-in terminal to a gas insulated substation (GIS) compartment. PMID:25815452

  3. Application of HFCT and UHF sensors in on-line partial discharge measurements for insulation diagnosis of high voltage equipment.

    PubMed

    Álvarez, Fernando; Garnacho, Fernando; Ortego, Javier; Sánchez-Urán, Miguel Ángel

    2015-03-25

    Partial discharge (PD) measurements provide valuable information for assessing the condition of high voltage (HV) insulation systems, contributing to their quality assurance. Different PD measuring techniques have been developed in the last years specially designed to perform on-line measurements. Non-conventional PD methods operating in high frequency bands are usually used when this type of tests are carried out. In PD measurements the signal acquisition, the subsequent signal processing and the capability to obtain an accurate diagnosis are conditioned by the selection of a suitable detection technique and by the implementation of effective signal processing tools. This paper proposes an optimized electromagnetic detection method based on the combined use of wideband PD sensors for measurements performed in the HF and UHF frequency ranges, together with the implementation of powerful processing tools. The effectiveness of the measuring techniques proposed is demonstrated through an example, where several PD sources are measured simultaneously in a HV installation consisting of a cable system connected by a plug-in terminal to a gas insulated substation (GIS) compartment.

  4. Application of HFCT and UHF Sensors in On-Line Partial Discharge Measurements for Insulation Diagnosis of High Voltage Equipment

    PubMed Central

    Álvarez, Fernando; Garnacho, Fernando; Ortego, Javier; Sánchez-Urán, Miguel Ángel

    2015-01-01

    Partial discharge (PD) measurements provide valuable information for assessing the condition of high voltage (HV) insulation systems, contributing to their quality assurance. Different PD measuring techniques have been developed in the last years specially designed to perform on-line measurements. Non-conventional PD methods operating in high frequency bands are usually used when this type of tests are carried out. In PD measurements the signal acquisition, the subsequent signal processing and the capability to obtain an accurate diagnosis are conditioned by the selection of a suitable detection technique and by the implementation of effective signal processing tools. This paper proposes an optimized electromagnetic detection method based on the combined use of wideband PD sensors for measurements performed in the HF and UHF frequency ranges, together with the implementation of powerful processing tools. The effectiveness of the measuring techniques proposed is demonstrated through an example, where several PD sources are measured simultaneously in a HV installation consisting of a cable system connected by a plug-in terminal to a gas insulated substation (GIS) compartment. PMID:25815452

  5. Operation Method for AC Motor Control during Power Interruption in Direct AC/AC Converter System

    NASA Astrophysics Data System (ADS)

    Shizu, Keiichiro; Azuma, Satoshi

    Direct AC/AC converters have been studied due to their potential use in power converters with no DC-link capacitor, which can contribute to the miniaturization of power converters. However, the absence of a DC-link capacitor makes it difficult to control the AC motor during power interruption. First, this paper proposes a system that realizes AC motor control during power interruption by utilizing a clamp capacitor. In general, direct AC/AC converters have a clamp circuit consisting of a rectifier diode(s) and a clamp capacitor in order to avoid over-voltages. In the proposed system, there is an additional semiconductor switch reverse-parallel to the rectifier diode(s), and the clamp capacitor voltage can be utilized for AC motor control by turning on the additional switch. Second, this paper discusses an operation method for AC motor control and clamp capacitor voltage control during power interruption. In the proposed method “DC-link voltage control”, the kinetic energy in the AC motor is transformed into electrical energy and stored in the clamp capacitor; the clamp capacitor is therefore charged and the capacitor voltage is controlled to remain constant at an instruction value. Third, this paper discusses a switching operation during power interruption. A dead-time is introduced between the operation of turning off all switches on the rectifier side and the operation of turning on the additional switch, which prevents the occurrence of a short circuit between the interrupted power source and the clamp capacitor. Finally, experimental results are presented. During power interruptions, an output current was continuously obtained and the clamp capacitor voltage was maintained to be equal to the instruction value of the capacitor voltage. These results indicate that both AC motor control and capacitor voltage control were successfully achieved by using the proposed system.

  6. The Power Behind the Controversy: Understanding Local Policy Elites' Perceptions on the Benefits and Risks Associated with High Voltage Power Line Installation in the State of Arkansas

    NASA Astrophysics Data System (ADS)

    Moyer, Rachael M.

    Following a proposal for the installation of high voltage power lines in northwest Arkansas, a controversial policy debate emerged. Proponents of the transmission line argue that such an installation is inevitable and necessary to efficiently and reliably support the identified electric load in the region. Opponents claim that the lines will degrade the natural environment and hamper the tourism-based local economy in affected regions, notably in Ozark Mountain areas. This study seeks to understand how local policy elites perceive the benefits and risks associated with proposed transmission lines, which is a critical step in comprehending the formation and changes of related government policies. First, based upon the dual process theory of judgment, this study systematically investigates the triadic relationships between (a) more profound personal value predispositions, (b) affects and feelings, and (c) perceived benefits and risks related to the proposed installation of high voltage power lines among local policy elites in the state of Arkansas. Next, this study focuses more specifically on the role of value predispositions, specific emotional dimensions of affect heuristics, and perceptions pertaining to high voltage power line risks and benefits. Using original data collected from a statewide Internet survey of 420 local leaders and key policymakers about their opinions on the related issues, other factors claimed by previous literature, including trust, knowledge level, and demographic characteristics are considered. Analytical results suggest that grid-group cultural predispositions, as deeply held core values within local policy elites' individual belief systems, both directly and indirectly -- through affective feelings -- shape perceived utility associated with the installation of high voltage power lines. Recognizing that risk perceptions factor into policy decisions, some practical considerations for better designing policy addressing controversial issues

  7. Development of an in-line filter to prevent intrusion of NO2 toxic vapors into A/C systems

    NASA Technical Reports Server (NTRS)

    Meneghelli, Barry; Mcnulty, R. J.; Springer, Mike; Lueck, Dale E.

    1995-01-01

    The hypergolic propellant nitrogen tetroxide (N2O4 or NTO) is routinely used in spacecraft launched at Kennedy Space Center (KSC) and Cape Canaveral Air Station (CCAS). In the case of a catastrophic failure of the spacecraft, there would be a release of the unspent propellant in the form of a toxic cloud. Inhalation of this material at downwind concentrations which may be as high as 20 parts per million (ppm) for 30 minutes in duration, may produce irritation to the eyes, nose and respiratory tract. Studies at both KSC and CCAS have shown that the indoor concentrations of N2O4 during a toxic release may range from 1 to 15 ppm and depend on the air change rate (ACR) for a particular building and whether or not the air conditioning (A/C) system has been shut down or left in an operating mode. This project was initiated in order to assess how current A/C systems could be easily modified to prevent personnel from being exposed to toxic vapors. A sample system has been constructed to test the ability of several types of filter material to capture the N2O4 vapors prior to their infiltration into the A/C system. Test results will be presented which compare the efficiencies of standard A/C filters, water wash systems, and chemically impregnated filter material in taking toxic vapors out of the incoming air stream.

  8. Health responses to a new high-voltage power line route: design of a quasi-experimental prospective field study in the Netherlands

    PubMed Central

    2014-01-01

    Background New high-voltage power transmission lines will be introduced due to increasing demand for reliable and renewable energy supplies. Some residents associate non-specific health complaints with exposure to electromagnetic fields from nearby power lines. This study protocol describes the design and rationale of a prospective study investigating whether the introduction of a new power line triggers health responses in residents living nearby. Methods/Design The study is designed as a quasi-experimental field study with two pretests during the construction of a new power line route, and two posttests after it has been put into operation. Key outcomes are self-reported non-specific somatic and cognitive health complaints, and attribution of these health complaints to a power line. The main determinant is proximity to the new power line route. One member of every household (n = 2379) residing in close proximity (0-500 meters) to the overhead parts of a new power line route in the Netherlands is invited to participate, as well as a sample of household members (n = 2382) residing farther away (500-2000 meters). Multilevel analysis will be employed to test whether an increase in key outcome measures is related to proximity to the line. Longitudinal structural equation models will be applied to test to what extent health responses are mediated by psychosocial health mechanisms and moderated by negative oriented personality traits. Discussion This is the first study to investigate health responses to a new power line route in a prospective manner. The results will provide theoretical insight into psychosocial mechanisms operating during the introduction of an environmental health risk, and may offer suggestions to policymakers and other stakeholders for minimizing adverse health responses when introducing new high-voltage power lines. PMID:24606914

  9. [Childhood leukaemia in a residential area with a high-voltage power line: approach according to the Dutch Community Health Services' guideline 'Cancer Clusters'].

    PubMed

    Hegger, Carola; Reedijk, Ardine M J

    2013-01-01

    The new Dutch Community Health Services' (GGD) guideline titled 'Cancer Clusters' describes a phased plan for investigating reported cancer clusters. In each phase, attention is paid to both health and environmental issues and their possible links to one another. Throughout the entire cluster investigation, good risk communication is essential. In accordance with the new guideline, the Rotterdam-Rijnmond Public Health Services investigated the incidence of childhood leukaemia in a residential area as well as the data available on the high-voltage power line located there. More children in this residential area had been diagnosed with leukaemia than expected. However, the children had not been subjected to prolonged exposure to strong magnetic fields emitted from the high-voltage power line. With this type of cluster investigation, it is not possible to establish a causal relationship between childhood leukaemia and high-voltage power lines. However, the research did provide stakeholders insight into the health-and-environment situation and thereby, the opportunity to assess the situation appropriately and to act accordingly, if desired.

  10. UPS with input commutation between ac and dc sources of power

    SciTech Connect

    Severinsky, A.J.

    1993-08-31

    An uninterruptible power supply is described, said power supply comprising: AC input terminal means for receiving a first AC voltage from an AC power source; DC input terminal means for receiving a first DC voltage from a DC power source; AC output terminal means for connecting to a load; converter means for converting said first AC voltage to a second DC voltage across electrical charge storage means coupled to said converter means, said second DC voltage being larger than the maximum peak voltage of said first AC voltage and said first DC voltage; switching means coupled to said AC power source and said DC power source for selectively connecting said AC power source or said DC power source to said converter means; inverter means coupled to said electrical charge storage means for receiving said second DC voltage and inverting said second DC voltage to a second AC voltage, said second AC voltage being coupled to said AC output terminal means; and control means coupled to said switching means for controlling the operation of said switching means, said control means operating said switching means to connect said AC power source to said converter means only when said first AC voltage is within a predetermined range and operating to connect said DC power source to said converter means when said first AC voltage is outside of said range.

  11. Digital ac monitor

    DOEpatents

    Hart, G.W.; Kern, E.C. Jr.

    1987-06-09

    An apparatus and method is provided for monitoring a plurality of analog ac circuits by sampling the voltage and current waveform in each circuit at predetermined intervals, converting the analog current and voltage samples to digital format, storing the digitized current and voltage samples and using the stored digitized current and voltage samples to calculate a variety of electrical parameters; some of which are derived from the stored samples. The non-derived quantities are repeatedly calculated and stored over many separate cycles then averaged. The derived quantities are then calculated at the end of an averaging period. This produces a more accurate reading, especially when averaging over a period in which the power varies over a wide dynamic range. Frequency is measured by timing three cycles of the voltage waveform using the upward zero crossover point as a starting point for a digital timer. 24 figs.

  12. Digital ac monitor

    DOEpatents

    Hart, George W.; Kern, Jr., Edward C.

    1987-06-09

    An apparatus and method is provided for monitoring a plurality of analog ac circuits by sampling the voltage and current waveform in each circuit at predetermined intervals, converting the analog current and voltage samples to digital format, storing the digitized current and voltage samples and using the stored digitized current and voltage samples to calculate a variety of electrical parameters; some of which are derived from the stored samples. The non-derived quantities are repeatedly calculated and stored over many separate cycles then averaged. The derived quantities are then calculated at the end of an averaging period. This produces a more accurate reading, especially when averaging over a period in which the power varies over a wide dynamic range. Frequency is measured by timing three cycles of the voltage waveform using the upward zero crossover point as a starting point for a digital timer.

  13. Composite rod insulators for ac power lines; Electrical performance of various designs at a coastal testing station

    SciTech Connect

    Houlgate, R.G.; Swift, D.A. )

    1990-10-01

    The electrical performance of thirty-six composite insulators - of four commercial types for each AC system level of 34.5 kV, 230 kV and 500 kV - has been determined at the CEGB insulator testing station, Brighton, England. The weathershed materials were epoxy-resin, ethylene propylene rubber and silicone rubber; half of the 230 kV insulators had no stress rings. Surface leakage current was recorded for surge levels of 25 mA, 150 mA and 500 mA; a special technique was developed to obtain the flashover statistics of the 500 kV insulators, thereby enabling performance of the composite insulator to be quantified relative to that of a string of cap and pin porcelain insulators of anti-fog design, the deterioration of the insulators was observed by making regular visual inspections. The practical consequences of the findings and the causes of the degradation are discussed.

  14. AC and DC power transmission

    SciTech Connect

    Not Available

    1985-01-01

    The technical and economic assessment of AC and DC transmission systems; long distance transmission, cable transmission, system inter-connection, voltage support, reactive compensation, stabilisation of systems; parallel operation of DC links with AC systems; comparison between alternatives for particular schemes. Design and application equipment: design, testing and application of equipment for HVDC, series and shunt static compensated AC schemes, including associated controls. Installations: overall design of stations and conductor arrangements for HVDC, series and shunt static AC schemes including insulation co-ordination. System analysis and modelling.

  15. Electrical and Biological Effects of Transmission Lines: A Review.

    SciTech Connect

    Lee, Jack M.

    1989-06-01

    This review describes the electrical properties of a-c and d-c transmission lines and the resulting effects on plants, animals, and people. Methods used by BPA to mitigate undesirable effects are also discussed. Although much of the information in this review pertains to high-voltage transmission lines, information on distribution lines and electrical appliances is included. The electrical properties discussed are electric and magnetic fields and corona: first for alternating-current (a-c) lines, then for direct current (d-c).

  16. Photopyroelectric ac calorimetric study of the nematic-smectic-A phase-transition line in binary liquid crystal mixtures with injected smectic-A phases.

    PubMed

    Caerels, J; Glorieux, C; Thoen, J

    2002-03-01

    Using a recently developed photopyroelectric ac calorimetric technique we investigate two binary liquid crystal mixtures with so-called injected smectic-A phases. Characteristic of these systems is the occurrence of nematic-to-smectic-A transition lines in the phase diagram of mixtures of pure compounds having only a nematic phase. The two binary systems are pentylcyanobiphenyl with either 4-n-propylcyclohexyl-carboxylate or 4-n-pentylphenyl 4(')-n-pentyloxybenzoate. Both these systems have domelike smectic-A ranges with narrow nematic ranges at the top. Near the top the N-SmA transitions are of first order and are crossing over to second order at a tricritical point on either side of the top with the increasing width of the nematic range. The obtained critical exponents are almost completely Fisher renormalized because of the strong concentration dependence of the nematic-to-smectic-A transition temperatures.

  17. The interaction of point defects with line dislocations in HVEM (high voltage electron microscope) irradiated Fe-Ni-Cr alloys

    SciTech Connect

    King, S.L.; Jenkins, M.L. . Dept. of Materials); Kirk, M.A. ); English, C.A. . Materials Development Div.)

    1990-05-01

    This paper presents results of a study of the interaction of point defects produced by high voltage electron microscope (HVEM) irradiation with pre-existing dislocations in austenitic Fe-15% 25%Ni-17%Cr alloys, aimed at the determination of the mechanisms of climb of dissociated dislocations. Dislocations were initially characterized at sub-threshold voltages (here 200kV) using the weak-beam technique. These dislocations were then irradiated with 1MeV electrons in the Argonne HVEM before being returned to a lower voltage microscope for post-irradiation characterization. Interstitial climb was seen only at particularly favorable sites, such as pre-existing jogs, whilst vacancies clustered near dislocations, forming stacking fault tetrahedra (SFT). Partial separations were also observed to have decreased after irradiation. The post-irradiation configuration was found to depend strongly on both dislocation character and pre-irradiation dislocation configuration. These results, and their relevance to the void swelling problem, are discussed. 52 refs., 8 figs.

  18. Field and laboratory studies on the impact of two Bt rice lines expressing a fusion protein Cry1Ab/1Ac on aquatic organisms.

    PubMed

    Wang, Yongmo; Huang, Jiacheng; Hu, Huawei; Li, Jianhong; Liu, Biao; Zhang, Guoan

    2013-06-01

    Genetically modified (GM) rice expressing Bt toxins is at the edge of commercial release in China. However, little information is available concerning the impact of Bt rice on aquatic organisms which are abundant in paddy field. A two-year study was conducted to assess the effects of two GM rice lines expressing a fusion protein Cry1Ab/1Ac (Bt rice) on three groups of zooplankton, rotifers, cladocerans and copepods in field conditions. Multi-factor ANOVA revealed that the population densities of rotifers, cladocerans and copepods in paddy field varied significantly between years and rice developmental stages, but did not differ significantly between Bt and non-Bt rice treatments. In all the field investigations, only one significant difference was found on copepods in the tillering stage of 2009, but the difference was not related to the presence of the Cry toxin. Under open-air conditions, we simulated the farming practice of straw mulch, using Bt rice straw as a food source for the water flea Daphnia hyalina. After one and two months of culture, the density of D. hyalina did not differ between Bt rice treatments and non-Bt rice treatments. A laboratory experiment found that purified Bt toxins Cry1Ab and Cry1Ac had no toxic effect on D. hyalina even in the treatment in which the Bt toxin concentration was as high as 2500ng/ml. Those above results indicate that the two Bt rice lines have no negative effect on the three groups of zooplankton. However, further studies are needed to compare the effects of Bt rice and non-Bt rice on the paddy zooplankton community in the context of integrated pest management which includes the use of pesticides. PMID:23523003

  19. ac bidirectional motor controller

    NASA Technical Reports Server (NTRS)

    Schreiner, K.

    1988-01-01

    Test data are presented and the design of a high-efficiency motor/generator controller at NASA-Lewis for use with the Space Station power system testbed is described. The bidirectional motor driver is a 20 kHz to variable frequency three-phase ac converter that operates from the high-frequency ac bus being designed for the Space Station. A zero-voltage-switching pulse-density-modulation technique is used in the converter to shape the low-frequency output waveform.

  20. Multilevel cascade voltage source inverter with seperate DC sources

    DOEpatents

    Peng, Fang Zheng; Lai, Jih-Sheng

    1997-01-01

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

  1. Multilevel cascade voltage source inverter with separate DC sources

    DOEpatents

    Peng, F.Z.; Lai, J.S.

    1997-06-24

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations. 15 figs.

  2. Multilevel cascade voltage source inverter with seperate DC sources

    DOEpatents

    Peng, Fang Zheng; Lai, Jih-Sheng

    2002-01-01

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

  3. Multilevel cascade voltage source inverter with seperate DC sources

    DOEpatents

    Peng, Fang Zheng; Lai, Jih-Sheng

    2001-04-03

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

  4. High voltage variable diameter insulator

    DOEpatents

    Vanacek, D.L.; Pike, C.D.

    1982-07-13

    A high voltage feedthrough assembly having a tubular insulator extending between the ground plane ring and the high voltage ring. The insulator is made of Pyrex and decreases in diameter from the ground plane ring to the high voltage ring, producing equipotential lines almost perpendicular to the wall of the insulator to optimize the voltage-holding capability of the feedthrough assembly.

  5. Uncertainty evaluation in the measurement of power frequency electric and magnetic fields from AC overhead power lines.

    PubMed

    Ztoupis, I N; Gonos, I F; Stathopulos, I A

    2013-11-01

    Measurements of power frequency electric and magnetic fields from alternating current power lines are carried out in order to evaluate the exposure levels of the human body on the general public. For any electromagnetic field measurement, it is necessary to define the sources of measurement uncertainty and determine the total measurement uncertainty. This paper is concerned with the problems of measurement uncertainty estimation, as the measurement uncertainty budget calculation techniques recommended in standardising documents and research studies are barely described. In this work the total uncertainty of power frequency field measurements near power lines in various measurement sites is assessed by considering not only all available equipment data, but also contributions that depend on the measurement procedures, environmental conditions and characteristics of the field source, which are considered to increase the error of measurement. A detailed application example for power frequency field measurements is presented here by accredited laboratory.

  6. Fiber-optic sensor for real-time monitoring of temperature on high voltage (400KV) power transmission lines

    NASA Astrophysics Data System (ADS)

    Gangopadhyay, Tarun K.; Paul, Mukul C.; Bjerkan, Leif

    2009-10-01

    On-line monitoring of temperature and sag in 400KV power transmission line has successfully been implemented by a novel device using fibre Bragg grating (FBG) sensors. The complete device has been fabricated with aluminum mount connected via fibre-optic cable and installed on ACSR power conductor for continuous two years measurement. This paper presents the excellent results and experience of the tests in controlled indoor environments conducted in Norway and real-field application on installed power conductor in India. Thus, better surveillance of the thermal and mechanical loads on power lines can be possible using this FBG sensor system.

  7. Development of polymer insulators for electrical and high-voltage power lines with the application of radiation-chemical technology

    SciTech Connect

    Kuznetsov, A.V.; Aleksandrov, G.N.; Ivanov, V.S.

    1993-12-31

    In the field of power engineering the problem of replacing traditional high-voltage porcelain and glass insulators by polymer insulators is being investigated. Polymers are desired which are relatively cheap and easy to process by molding. A copolymer of ethylene and vinyl acetate (EVA) filled aluminium hydroxide satisfys the requirements. In order to increase the heat stability of EVA, radiation-chemical technology was used in the present work. A pilot plant with a cobalt 60 radionuclide source was used as the source of ionizing radiation. The process of cross-linking EVA is described.

  8. A Passive EMI Filter with Access to the Ungrounded Motor Neutral Line-The Case that a General-Purpose Inverter is Directly Connected to a Three-Phase Grounded Voltage Source-

    NASA Astrophysics Data System (ADS)

    Doumoto, Takafumi; Akagi, Hirofumi

    This paper proposes a small-sized passive EMI filter for the purpose of eliminating high-frequency shaft voltage and ground leakage current from an ac motor. The motor is driven by a general-purpose PWM inverter connected to a three-phase grounded voltage source. The passive EMI filter requires access to the ungrounded neutral point of the motor. This unique circuit configuration makes the common-mode inductor effective in reducing the high-frequency common-mode voltage generated by the PWM inverter with a carrier frequency of 15kHz. As a result, both high-frequency shaft voltage and ground leakage current can be eliminated very efficiently. However, the common-mode inductor may not play any role in reducing the low-frequency common-mode voltage generated by the diode rectifier, so that a low-frequency component still remains in the shaft voltage. Such a low-frequency shaft voltage may not produce any bad effect on motor bearings. The validity and effectiveness of the EMI filter is verified by experimental results obtained from a 200-V 5-kVA laboratory system.

  9. The pore-lining region of shaker voltage-gated potassium channels: comparison of beta-barrel and alpha-helix bundle models.

    PubMed Central

    Kerr, I D; Sansom, M S

    1997-01-01

    Although there is a large body of site-directed mutagenesis data that identify the pore-lining sequence of the voltage-gated potassium channel, the structure of this region remains unknown. We have interpreted the available biochemical data as a set of topological and orientational restraints and employed these restraints to produce molecular models of the potassium channel pore region, H5. The H5 sequence has been modeled either as a tetramer of membrane-spanning beta-hairpins, thus producing an eight-stranded beta-barrel, or as a tetramer of incompletely membrane-spanning alpha-helical hairpins, thus producing an eight-staved alpha-helix bundle. In total, restraints-directed modeling has produced 40 different configurations of the beta-barrel model, each configuration comprising an ensemble of 20 structures, and 24 different configurations of the alpha-helix bundle model, each comprising an ensemble of 24 structures. Thus, over 1300 model structures for H5 have been generated. Configurations have been ranked on the basis of their predicted pore properties and on the extent of their agreement with the biochemical data. This ranking is employed to identify particular configurations of H5 that may be explored further as models of the pore-lining region of the voltage-gated potassium channel pore. Images FIGURE 7 FIGURE 12 PMID:9251779

  10. 29 CFR 1926.1410 - Power line safety (all voltages)-equipment operations closer than the Table A zone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... high-visibility markings, to prevent electrical contact. However, this provision does not apply to work... for the purposes of this paragraph. (v) Until November 8, 2013, the following procedure may be... be prohibited from touching the load line above the insulating link/device and crane....

  11. Module Two: Voltage; Basic Electricity and Electronics Individualized Learning System.

    ERIC Educational Resources Information Center

    Bureau of Naval Personnel, Washington, DC.

    In this module the student will study and learn what voltage is, how it is generated, what AC (alternating current) and DC (direct current) are and why both kinds are needed, and how to measure voltages. The module is divided into six lessons: EMF (electromotive force) from chemical action, magnetism, electromagnetic induction, AC voltage, the…

  12. Charge Voltages from Magnetization Dynamics

    NASA Astrophysics Data System (ADS)

    Hoffmann, Axel

    2013-03-01

    The main challenge of spin caloritronics is to establish a connection between heat currents and spin currents. Towards this end, spin Hall effects have become very important, since they allow to convert a pure spin current into a transverse charge voltage. I will show how these spin Hall effects can be characterized with great accuracy using spin pumping, where the excitation of ferromagnetic resonance generates a pure spin current in an adjacent non-magnetic conductor.[3] The change in the line-width of the ferromagnetic resonance determines the spin-mixing conductance and thus after proper calibration of the rf magnetic fields and the concomitant opening angles of the magnetization precession, allows to determine the magnitude of the spin current. The charge current generated from inverse spin Hall effect is measured through the associated electrical voltage and the ration of spin and charge current directly determines the spin Hall angle. Furthermore I will present an alternative approach for converting magnetization dynamics into measurable charge voltages. Namely, the dissipation of magnetization dynamics in thin films generally also results in a temperature gradient perpendicular to the film, since the supporting substrate acts as a heat sink. This in turn can generate a transverse voltage through the anomalous Nernst effect. Interestingly this allows to detect spin waves with very good signal to noise[4] and unlike optical or inductive detection techniques there is practically no lower limit for the wavelength of the detected spin waves. Financial support was through U.S. Department of Energy, Office of Science under Contract no. DE-AC02-06CH11357.

  13. STABILITY OF HIGH VOLTAGE MODULATORS FOR NONLINEAR LOADS

    SciTech Connect

    PAWLEY,J.C; TOOKER,J; PEAVY,J; CARY,W.P; NEREM,A; HOYT,D; LOHR,J

    2003-10-01

    OAK-B135 Gyrotrons have a nonlinear voltage--current characteristic such that the small signal or ac impedance changes as operational voltage and currents are reached. The ac impedance determines the stability of a voltage or current control system. this can become particularly challenging when several gyrotron are connected in parallel to a single modulator. With all gyrotrons hooked to a common ground, large current loops can be generated as well as non-canceling currents in individual coaxial lines. These inequalities can provide the required feedback impulse to start an oscillation condition in the power system for the tubes. Recent operation of two CPI 110 GHz gyrotrons in the MN class from a single modulator on DIII-D has shown instability in the power system. An oscillation in the drive current occurs at various points in the ramp up and flat top portions of the 80 kV voltage pulse with each tube drawing 40 A at full voltage. Efforts to stabilize these instabilities are presented along with some modeling and examination of the issues for gyrotron modulators.

  14. Monitoring tumor motion with on-line mega-voltage cone-beam computed tomography imaging in a cine mode

    NASA Astrophysics Data System (ADS)

    Reitz, Bodo; Gayou, Olivier; Parda, David S.; Miften, Moyed

    2008-02-01

    Accurate daily patient localization is becoming increasingly important in external-beam radiotherapy (RT). Mega-voltage cone-beam computed tomography (MV-CBCT) utilizing a therapy beam and an on-board electronic portal imager can be used to localize tumor volumes and verify the patient's position prior to treatment. MV-CBCT produces a static volumetric image and therefore can only account for inter-fractional changes. In this work, the feasibility of using the MV-CBCT raw data as a fluoroscopic series of portal images to monitor tumor changes due to e.g. respiratory motion was investigated. A method was developed to read and convert the CB raw data into a cine. To improve the contrast-to-noise ratio on the MV-CB projection data, image post-processing with filtering techniques was investigated. Volumes of interest from the planning CT were projected onto the MV-cine. Because of the small exposure and the varying thickness of the patient depending on the projection angle, soft-tissue contrast was limited. Tumor visibility as a function of tumor size and projection angle was studied. The method was well suited in the upper chest, where motion of the tumor as well as of the diaphragm could be clearly seen. In the cases of patients with non-small cell lung cancer with medium or large tumor masses, we verified that the tumor mass was always located within the PTV despite respiratory motion. However for small tumors the method is less applicable, because the visibility of those targets becomes marginal. Evaluation of motion in non-superior-inferior directions might also be limited for small tumor masses. Viewing MV-CBCT data in a cine mode adds to the utility of MV-CBCT for verification of tumor motion and for deriving individualized treatment margins.

  15. Monitoring tumor motion with on-line mega-voltage cone-beam computed tomography imaging in a cine mode.

    PubMed

    Reitz, Bodo; Gayou, Olivier; Parda, David S; Miften, Moyed

    2008-02-21

    Accurate daily patient localization is becoming increasingly important in external-beam radiotherapy (RT). Mega-voltage cone-beam computed tomography (MV-CBCT) utilizing a therapy beam and an on-board electronic portal imager can be used to localize tumor volumes and verify the patient's position prior to treatment. MV-CBCT produces a static volumetric image and therefore can only account for inter-fractional changes. In this work, the feasibility of using the MV-CBCT raw data as a fluoroscopic series of portal images to monitor tumor changes due to e.g. respiratory motion was investigated. A method was developed to read and convert the CB raw data into a cine. To improve the contrast-to-noise ratio on the MV-CB projection data, image post-processing with filtering techniques was investigated. Volumes of interest from the planning CT were projected onto the MV-cine. Because of the small exposure and the varying thickness of the patient depending on the projection angle, soft-tissue contrast was limited. Tumor visibility as a function of tumor size and projection angle was studied. The method was well suited in the upper chest, where motion of the tumor as well as of the diaphragm could be clearly seen. In the cases of patients with non-small cell lung cancer with medium or large tumor masses, we verified that the tumor mass was always located within the PTV despite respiratory motion. However for small tumors the method is less applicable, because the visibility of those targets becomes marginal. Evaluation of motion in non-superior-inferior directions might also be limited for small tumor masses. Viewing MV-CBCT data in a cine mode adds to the utility of MV-CBCT for verification of tumor motion and for deriving individualized treatment margins.

  16. Solid-state Marx based two-switch voltage modulator for the On-Line Isotope Mass Separator accelerator at the European Organization for Nuclear Research

    NASA Astrophysics Data System (ADS)

    Redondo, L. M.; Silva, J. Fernando; Canacsinh, H.; Ferrão, N.; Mendes, C.; Soares, R.; Schipper, J.; Fowler, A.

    2010-07-01

    A new circuit topology is proposed to replace the actual pulse transformer and thyratron based resonant modulator that supplies the 60 kV target potential for the ion acceleration of the On-Line Isotope Mass Separator accelerator, the stability of which is critical for the mass resolution downstream separator, at the European Organization for Nuclear Research. The improved modulator uses two solid-state switches working together, each one based on the Marx generator concept, operating as series and parallel switches, reducing the stress on the series stacked semiconductors, and also as auxiliary pulse generator in order to fulfill the target requirements. Preliminary results of a 10 kV prototype, using 1200 V insulated gate bipolar transistors and capacitors in the solid-state Marx circuits, ten stages each, with an electrical equivalent circuit of the target, are presented, demonstrating both the improved voltage stability and pulse flexibility potential wanted for this new modulator.

  17. Solid-state Marx based two-switch voltage modulator for the On-Line Isotope Mass Separator accelerator at the European Organization for Nuclear Research.

    PubMed

    Redondo, L M; Silva, J Fernando; Canacsinh, H; Ferrão, N; Mendes, C; Soares, R; Schipper, J; Fowler, A

    2010-07-01

    A new circuit topology is proposed to replace the actual pulse transformer and thyratron based resonant modulator that supplies the 60 kV target potential for the ion acceleration of the On-Line Isotope Mass Separator accelerator, the stability of which is critical for the mass resolution downstream separator, at the European Organization for Nuclear Research. The improved modulator uses two solid-state switches working together, each one based on the Marx generator concept, operating as series and parallel switches, reducing the stress on the series stacked semiconductors, and also as auxiliary pulse generator in order to fulfill the target requirements. Preliminary results of a 10 kV prototype, using 1200 V insulated gate bipolar transistors and capacitors in the solid-state Marx circuits, ten stages each, with an electrical equivalent circuit of the target, are presented, demonstrating both the improved voltage stability and pulse flexibility potential wanted for this new modulator.

  18. Research on the Error Characteristics of a 110 kV Optical Voltage Transformer under Three Conditions: In the Laboratory, Off-Line in the Field and During On-Line Operation.

    PubMed

    Xiao, Xia; Hu, Haoliang; Xu, Yan; Lei, Min; Xiong, Qianzhu

    2016-01-01

    Optical voltage transformers (OVTs) have been applied in power systems. When performing accuracy performance tests of OVTs large differences exist between the electromagnetic environment and the temperature variation in the laboratory and on-site. Therefore, OVTs may display different error characteristics under different conditions. In this paper, OVT prototypes with typical structures were selected to be tested for the error characteristics with the same testing equipment and testing method. The basic accuracy, the additional error caused by temperature and the adjacent phase in the laboratory, the accuracy in the field off-line, and the real-time monitoring error during on-line operation were tested. The error characteristics under the three conditions-laboratory, in the field off-line and during on-site operation-were compared and analyzed. The results showed that the effect of the transportation process, electromagnetic environment and the adjacent phase on the accuracy of OVTs could be ignored for level 0.2, but the error characteristics of OVTs are dependent on the environmental temperature and are sensitive to the temperature gradient. The temperature characteristics during on-line operation were significantly superior to those observed in the laboratory.

  19. Research on the Error Characteristics of a 110 kV Optical Voltage Transformer under Three Conditions: In the Laboratory, Off-Line in the Field and During On-Line Operation.

    PubMed

    Xiao, Xia; Hu, Haoliang; Xu, Yan; Lei, Min; Xiong, Qianzhu

    2016-01-01

    Optical voltage transformers (OVTs) have been applied in power systems. When performing accuracy performance tests of OVTs large differences exist between the electromagnetic environment and the temperature variation in the laboratory and on-site. Therefore, OVTs may display different error characteristics under different conditions. In this paper, OVT prototypes with typical structures were selected to be tested for the error characteristics with the same testing equipment and testing method. The basic accuracy, the additional error caused by temperature and the adjacent phase in the laboratory, the accuracy in the field off-line, and the real-time monitoring error during on-line operation were tested. The error characteristics under the three conditions-laboratory, in the field off-line and during on-site operation-were compared and analyzed. The results showed that the effect of the transportation process, electromagnetic environment and the adjacent phase on the accuracy of OVTs could be ignored for level 0.2, but the error characteristics of OVTs are dependent on the environmental temperature and are sensitive to the temperature gradient. The temperature characteristics during on-line operation were significantly superior to those observed in the laboratory. PMID:27537895

  20. Research on the Error Characteristics of a 110 kV Optical Voltage Transformer under Three Conditions: In the Laboratory, Off-Line in the Field and During On-Line Operation

    PubMed Central

    Xiao, Xia; Hu, Haoliang; Xu, Yan; Lei, Min; Xiong, Qianzhu

    2016-01-01

    Optical voltage transformers (OVTs) have been applied in power systems. When performing accuracy performance tests of OVTs large differences exist between the electromagnetic environment and the temperature variation in the laboratory and on-site. Therefore, OVTs may display different error characteristics under different conditions. In this paper, OVT prototypes with typical structures were selected to be tested for the error characteristics with the same testing equipment and testing method. The basic accuracy, the additional error caused by temperature and the adjacent phase in the laboratory, the accuracy in the field off-line, and the real-time monitoring error during on-line operation were tested. The error characteristics under the three conditions—laboratory, in the field off-line and during on-site operation—were compared and analyzed. The results showed that the effect of the transportation process, electromagnetic environment and the adjacent phase on the accuracy of OVTs could be ignored for level 0.2, but the error characteristics of OVTs are dependent on the environmental temperature and are sensitive to the temperature gradient. The temperature characteristics during on-line operation were significantly superior to those observed in the laboratory. PMID:27537895

  1. Increased Ac excision (iae): Arabidopsis thaliana mutations affecting Ac transposition.

    PubMed

    Jarvis, P; Belzile, F; Page, T; Dean, C

    1997-05-01

    The maize transposable element Ac is highly active in the heterologous hosts tobacco and tomato, but shows very much reduced levels of activity in Arabidopsis. A mutagenesis experiment was undertaken with the aim of identifying Arabidopsis host factors responsible for the observed low levels of Ac activity. Seed from a line carrying a single copy of the Ac element inserted into the streptomycin phosphotransferase (SPT) reporter fusion, and which displayed typically low levels of Ac activity, were mutagenized using gamma rays. Nineteen mutants displaying high levels of somatic Ac activity, as judged by their highly variegated phenotypes, were isolated after screening the M2 generation on streptomycin-containing medium. The mutations fall into two complementation groups, iae1 and iae2, are unlinked to the SPT::Ac locus and segregate in a Mendelian fashion. The iae1 mutation is recessive and the iae2 mutation is semi-dominant. The iae1 and iae2 mutants show 550- and 70-fold increases, respectively, in the average number of Ac excision sectors per cotyledon. The IAE1 locus maps to chromosome 2, whereas the SPT::Ac reporter maps to chromosome 3. A molecular study of Ac activity in the iae1 mutant confirmed the very high levels of Ac excision predicted using the phenotypic assay, but revealed only low levels of Ac re-insertion. Analyses of germinal transposition in the iae1 mutant demonstrated an average germinal excision frequency of 3% and a frequency of independent Ac re-insertions following germinal excision of 22%. The iae mutants represents a possible means of improving the efficiency of Ac/Ds transposon tagging systems in Arabidopsis, and will enable the dissection of host involvement in Ac transposition and the mechanisms employed for controlling transposable element activity.

  2. Experimental validation of a high voltage pulse measurement method.

    SciTech Connect

    Cular, Stefan; Patel, Nishant Bhupendra; Branch, Darren W.

    2013-09-01

    This report describes X-cut lithium niobates (LiNbO3) utilization for voltage sensing by monitoring the acoustic wave propagation changes through LiNbO3 resulting from applied voltage. Direct current (DC), alternating current (AC) and pulsed voltage signals were applied to the crystal. Voltage induced shift in acoustic wave propagation time scaled quadratically for DC and AC voltages and linearly for pulsed voltages. The measured values ranged from 10 - 273 ps and 189 ps 2 ns for DC and non-DC voltages, respectively. Data suggests LiNbO3 has a frequency sensitive response to voltage. If voltage source error is eliminated through physical modeling from the uncertainty budget, the sensors U95 estimated combined uncertainty could decrease to ~0.025% for DC, AC, and pulsed voltage measurements.

  3. Electron stripping processes of H⁻ ion beam in the 80 kV high voltage extraction column and low energy beam transport line at LANSCE.

    PubMed

    Draganic, I N

    2016-02-01

    Basic vacuum calculations were performed for various operating conditions of the Los Alamos National Neutron Science H(-) Cockcroft-Walton (CW) injector and the Ion Source Test Stand (ISTS). The vacuum pressure was estimated for both the CW and ISTS at five different points: (1) inside the H(-) ion source, (2) in front of the Pierce electrode, (3) at the extraction electrode, (4) at the column electrode, and (5) at the ground electrode. A static vacuum analysis of residual gases and the working hydrogen gas was completed for the normal ion source working regime. Gas density and partial pressure were estimated for the injected hydrogen gas. The attenuation of H(-) beam current and generation of electron current in the high voltage acceleration columns and low energy beam transport lines were calculated. The interaction of H(-) ions on molecular hydrogen (H2) is discussed as a dominant collision process in describing electron stripping rates. These results are used to estimate the observed increase in the ratio of electrons to H(-) ion beam in the ISTS beam transport line.

  4. Electron stripping processes of H- ion beam in the 80 kV high voltage extraction column and low energy beam transport line at LANSCE

    NASA Astrophysics Data System (ADS)

    Draganic, I. N.

    2016-02-01

    Basic vacuum calculations were performed for various operating conditions of the Los Alamos National Neutron Science H- Cockcroft-Walton (CW) injector and the Ion Source Test Stand (ISTS). The vacuum pressure was estimated for both the CW and ISTS at five different points: (1) inside the H- ion source, (2) in front of the Pierce electrode, (3) at the extraction electrode, (4) at the column electrode, and (5) at the ground electrode. A static vacuum analysis of residual gases and the working hydrogen gas was completed for the normal ion source working regime. Gas density and partial pressure were estimated for the injected hydrogen gas. The attenuation of H- beam current and generation of electron current in the high voltage acceleration columns and low energy beam transport lines were calculated. The interaction of H- ions on molecular hydrogen (H2) is discussed as a dominant collision process in describing electron stripping rates. These results are used to estimate the observed increase in the ratio of electrons to H- ion beam in the ISTS beam transport line.

  5. On-line optimization of battery open circuit voltage for improved state-of-charge and state-of-health estimation

    NASA Astrophysics Data System (ADS)

    Tong, Shijie; Klein, Matthew P.; Park, Jae Wan

    2015-10-01

    A battery management system (BMS) ensures performance, safety and longevity of a battery energy storage system in an embedded environment. One important task for a BMS is to estimate the state of charge (SoC) and state of health (SoH) of a battery. The correlation between battery open circuit voltage (OCV) and SoC is an important reference for state estimation. The OCV-SoC correlation changes with respect to battery degradation. To improve the accuracy of state estimation, it is important to have the OCV-SoC correlation updated periodically. This work presents a solution by proposing a novel SoH(SoC) correlation as part of the battery equivalent circuit model (ECM). On-line optimization of SoH(SoC) correlation implicitly optimizes the OCV(SoC) correlation, as well as the capacity of a battery. An associated state and parameter dual estimator is proposed incorporating an Extended Kalman Filter (EKF) as a state observer, Recursive Least Square (RLS) algorithm as an internal resistance identifier, and Parameter Varying Approach as the SoH(SoC) correlation identifier. Battery experiment and simulation results validate that updating the SoH-SoC correlation effectively tracks battery SoH on-line. Furthermore, it implicitly updates OCV(SoC) function, further improving SoC estimation accuracy by 0.5%∼3%.

  6. High voltage variable diameter insulator

    DOEpatents

    Vanecek, David L.; Pike, Chester D.

    1984-01-01

    A high voltage feedthrough assembly (10) having a tubular insulator (15) extending between the ground plane ring (16) and the high voltage ring (30). The insulator (15) is made of Pyrex and decreases in diameter from the ground plane ring (16) to the high voltage ring (30), producing equipotential lines almost perpendicular to the wall (27) of the insulator (15) to optimize the voltage-holding capability of the feedthrough assembly (10).

  7. Cell Cycle-Dependent Localization of Voltage-Dependent Calcium Channels and the Mitotic Apparatus in a Neuroendocrine Cell Line(AtT-20)

    PubMed Central

    Loechner, Karen J.; Salmon, Wendy C.; Fu, Jie; Patel, Shipra; McLaughlin, James T.

    2009-01-01

    Changes in intracellular calcium are necessary for the successful progression of mitosis in many cells. Both elevation and reduction in intracellular calcium can disrupt mitosis by mechanisms that remain ill defined. In this study we explore the role of transmembrane voltage-gated calcium channels (CaV channels) as regulators of mitosis in the mouse corticotroph cell line (AtT-20). We report that the nifedipine-sensitive isoform CaV1.2 is localized to the “poleward side” of kinetechores during metaphase and at the midbody during cytokinesis. A second nifedipine-sensitive isoform, CaV1.3, is present at the mid-spindle zone in telophase, but is also seen at the midbody. Nifedipine reduces the rate of cell proliferation, and, utilizing time-lapse microscopy, we show that this is due to a block at the prometaphase stage of the cell cycle. Using Fluo-4 we detect calcium fluxes at sites corresponding to the mid-spindle zone and the midbody region. Another calcium dye, Fura PE3/AM, causes an inhibition of mitosis prior to anaphase that we attribute to a chelation of intracellular calcium. Our results demonstrate a novel, isoform-specific localization of CaV1 channels during cell division and suggest a possible role for these channels in the calcium-dependent events underlying mitotic progression in pituitary corticotrophs. PMID:20130814

  8. Melatonin affects voltage-dependent calcium and potassium currents in MCF-7 cell line cultured either in growth or differentiation medium.

    PubMed

    Squecco, Roberta; Tani, Alessia; Zecchi-Orlandini, Sandra; Formigli, Lucia; Francini, Fabio

    2015-07-01

    Big efforts have been dedicated up to now to identify novel targets for cancer treatment. The peculiar biophysical profile and the atypical ionic channels activity shown by diverse types of human cancers suggest that ion channels may be possible targets in cancer therapy. Earlier studies have shown that melatonin exerts an oncostatic action on different tumors. In particular, it was shown that melatonin was able to inhibit growth/viability and proliferation, to reduce the invasiveness and metastatic properties of human estrogen-sensitive breast adenocarcinoma MCF-7 cell line cultured in growth medium, with substantial impairments of epidermal growth factor (EGF) and Notch-1-mediated signaling. The purpose of this work was to evaluate on MCF-7 cells the possible effects of melatonin on the biophysical features known to have a role in proliferation and differentiation, by using the patch-clamp technique. Our results show that in cells cultured in growth as well as in differentiation medium melatonin caused a hyperpolarization of resting membrane potential paralleled by significant changes of the inward Ca(2+) currents (T- and L-type), outward delayed rectifier K(+) currents and cell capacitance. All these effects are involved in MCF-7 growth and differentiation. These findings strongly suggest that melatonin, acting as a modulator of different voltage-dependent ion channels, might be considered a new promising tool for specifically disrupting cell viability and differentiation pathways in tumour cells with possible beneficial effects on cancer therapy. PMID:25843408

  9. Effects of water management practices on residue decomposition and degradation of Cry1Ac protein from crop-wild Bt rice hybrids and parental lines during winter fallow season.

    PubMed

    Xiao, Manqiu; Dong, Shanshan; Li, Zhaolei; Tang, Xu; Chen, Yi; Yang, Shengmao; Wu, Chunyan; Ouyang, Dongxin; Fang, Changming; Song, Zhiping

    2015-12-01

    Rice is the staple diet of over half of the world's population and Bacillus thuringiensis (Bt) rice expressing insecticidal Cry proteins is ready for deployment. An assessment of the potential impact of Bt rice on the soil ecosystem under varied field management practices is urgently required. We used litter bags to assess the residue (leaves, stems and roots) decomposition dynamics of two transgenic rice lines (Kefeng6 and Kefeng8) containing stacked genes from Bt and sck (a modified CpTI gene encoding a cowpea trypsin inhibitor) (Bt/CpTI), a non-transgenic rice near-isoline (Minghui86), wild rice (Oryza rufipogon) and crop-wild Bt rice hybrid under contrasting conditions (drainage or continuous flooding) in the field. No significant difference was detected in the remaining mass, total C and total N among cultivars under aerobic conditions, whereas significant differences in the remaining mass and total C were detected between Kefeng6 and Kefeng8 and Minghui86 under the flooded condition. A higher decomposition rate constant (km) was measured under the flooded condition compared with the aerobic condition for leaf residues, whereas the reverse was observed for root residues. The enzyme-linked immunosorbent assay (ELISA), which was used to monitor the changes in the Cry1Ac protein in Bt rice residues, indicated that (1) the degradation of the Cry1Ac protein under both conditions best fit first-order kinetics, and the predicted DT50 (50% degradation time) of the Cry1Ac protein ranged from 3.6 to 32.5 days; (2) the Cry1Ac protein in the residue degraded relatively faster under aerobic conditions; and (3) by the end of the study (~154 days), the protein was present at a low concentration in the remaining residues under both conditions. The degradation rate constant was negatively correlated with the initial carbon content and positively correlated with the initial Cry1Ac protein concentration, but it was only correlated with the mass decomposition rate constants under

  10. A multilevel voltage-source inverter with separate dc sources for static var generation

    SciTech Connect

    Peng, Fang Zheng |; Lai, Jih-Sheng; McKeever, J.; VanCoevering, J.

    1995-09-01

    A new multilevel voltage-source inverter with a separate dc sources is proposed for high-voltage, high-power applications, such as flexible ac transmission systems (FACTS) including static var generation (SVG), power line conditioning, series compensation, phase shifting, voltage balancing, fuel cell and photovoltaic utility systems interfacing, etc. The new M-level inverter consists of (M-1)/2 single phase full bridges in which each bridge has its own separate dc source. This inverter can generate almost sinusoidal waveform voltage with only one time switching per cycle as the number of levels increases. It can solve the problems of conventional transformer-based multipulse inverters and the problems of the multilevel diode-clamped inverter and the multilevel flying capacitor inverter. To demonstrate the superiority of the new inverter, a SVG system using the new inverter topology is discussed through analysis, simulation and experiment.

  11. An automatic bridge for inductive voltage dividers

    SciTech Connect

    Chang, P.; Liang, C.P.; Hsiao, J.C.

    1994-12-31

    We describe an automatic, injection-type bridge for inductive voltage divider (IVD) applications at low audio frequencies. We used it to self-calibrate programmable IVDs fabricated in house, by an automated {open_quotes}boot-strap{close_quotes} procedure. It is the heart of our reference standard for ac voltage ratios as well as a calibration system for IVDs.

  12. Infrared thermography at EDF: common technique for high-voltage lines but new in monitoring and diagnosis of PWR plant components

    NASA Astrophysics Data System (ADS)

    Provost, Daniel

    1996-03-01

    Infrared thermography is a remarkable aid in maintenance, and has been used for a number of years in testing high-voltage lines and transformer substations. Electricite de France (EDF) has developed a special infrared thermography system for this type of application. Until recently, use of IRT in both fossil and nuclear power plants was only sporadic and depended on the interest shown in the technique by individual maintenance managers. In power stations, it was primarily used for tests on switchyards, electrical control cabinets and insulation. The General Engineering Department of the EDF Generation and Transmission Division was responsible for assessing new equipment and studying special development requirements as they arose. Routine infrared thermography tests were performed by two teams from the Division, one handling northern France and the other southern France. Today, infrared thermography has become a fully-fledged monitoring and diagnosis tool in its own right, and related activities are being reorganized accordingly. Its recent success can be attributed to a number of factors: more high-powered IRT techniques, valuable feedback from American utility companies, and technical and economic assessments conducted by EDF over the last two years on equipment such as electrical and mechanical components, valves and insulation. EDF's reorganization of infrared thermography activities will begin with an overview of the resources now existing within the company. This inventory will be carried out by the General Engineering Department. At the same time, a report will be drawn up bearing on IRT testing over the last decade in conventional and nuclear power plants in France and the United States. Lastly, EDF will draw up a list of components to be monitored in this way, essentially on the basis of RCM studies. These measures will provide power plants with a catalogue of infrared thermography applications for specific component/failure combinations.

  13. High-voltage portable pulsed power supply fed by low voltage source

    NASA Astrophysics Data System (ADS)

    Rezanejad, Mohammad; Sheikholeslami, Abdolreza; Adabi, Jafar; Valinejad, Mohammadreza

    2016-05-01

    This article proposes a new structure of voltage multiplier for portable pulsed power applications. In this configuration, which is based on capacitor-diode voltage multiplier, the capacitors are charged by low AC input voltage and discharge through the load in series during pulse generation mode. The proposed topology is achieved by integrating of solid-state switches with conventional voltage multiplier, which can increase the low input voltage step by step and generate high-voltage high-frequency pulsed power across the load. After some discussion, simulations and experimental results are provided to verify the effectiveness of the proposed topology.

  14. Modelling a single phase voltage controlled rectifier using Laplace transforms

    NASA Technical Reports Server (NTRS)

    Kraft, L. Alan; Kankam, M. David

    1992-01-01

    The development of a 20 kHz, AC power system by NASA for large space projects has spurred a need to develop models for the equipment which will be used on these single phase systems. To date, models for the AC source (i.e., inverters) have been developed. It is the intent of this paper to develop a method to model the single phase voltage controlled rectifiers which will be attached to the AC power grid as an interface for connected loads. A modified version of EPRI's HARMFLO program is used as the shell for these models. The results obtained from the model developed in this paper are quite adequate for the analysis of problems such as voltage resonance. The unique technique presented in this paper uses the Laplace transforms to determine the harmonic content of the load current of the rectifier rather than a curve fitting technique. Laplace transforms yield the coefficient of the differential equations which model the line current to the rectifier directly.

  15. Voltage balanced multilevel voltage source converter system

    DOEpatents

    Peng, Fang Zheng; Lai, Jih-Sheng

    1997-01-01

    A voltage balanced multilevel converter for high power AC applications such as adjustable speed motor drives and back-to-back DC intertie of adjacent power systems. This converter provides a multilevel rectifier, a multilevel inverter, and a DC link between the rectifier and the inverter allowing voltage balancing between each of the voltage levels within the multilevel converter. The rectifier is equipped with at least one phase leg and a source input node for each of the phases. The rectifier is further equipped with a plurality of rectifier DC output nodes. The inverter is equipped with at least one phase leg and a load output node for each of the phases. The inverter is further equipped with a plurality of inverter DC input nodes. The DC link is equipped with a plurality of rectifier charging means and a plurality of inverter discharging means. The plurality of rectifier charging means are connected in series with one of the rectifier charging means disposed between and connected in an operable relationship with each adjacent pair of rectifier DC output nodes. The plurality of inverter discharging means are connected in series with one of the inverter discharging means disposed between and connected in an operable relationship with each adjacent pair of inverter DC input nodes. Each of said rectifier DC output nodes are individually electrically connected to the respective inverter DC input nodes. By this means, each of the rectifier DC output nodes and each of the inverter DC input nodes are voltage balanced by the respective charging and discharging of the rectifier charging means and the inverter discharging means.

  16. Voltage balanced multilevel voltage source converter system

    DOEpatents

    Peng, F.Z.; Lai, J.S.

    1997-07-01

    Disclosed is a voltage balanced multilevel converter for high power AC applications such as adjustable speed motor drives and back-to-back DC intertie of adjacent power systems. This converter provides a multilevel rectifier, a multilevel inverter, and a DC link between the rectifier and the inverter allowing voltage balancing between each of the voltage levels within the multilevel converter. The rectifier is equipped with at least one phase leg and a source input node for each of the phases. The rectifier is further equipped with a plurality of rectifier DC output nodes. The inverter is equipped with at least one phase leg and a load output node for each of the phases. The inverter is further equipped with a plurality of inverter DC input nodes. The DC link is equipped with a plurality of rectifier charging means and a plurality of inverter discharging means. The plurality of rectifier charging means are connected in series with one of the rectifier charging means disposed between and connected in an operable relationship with each adjacent pair of rectifier DC output nodes. The plurality of inverter discharging means are connected in series with one of the inverter discharging means disposed between and connected in an operable relationship with each adjacent pair of inverter DC input nodes. Each of said rectifier DC output nodes are individually electrically connected to the respective inverter DC input nodes. By this means, each of the rectifier DC output nodes and each of the inverter DC input nodes are voltage balanced by the respective charging and discharging of the rectifier charging means and the inverter discharging means. 15 figs.

  17. High voltage pulse conditioning

    DOEpatents

    Springfield, Ray M.; Wheat, Jr., Robert M.

    1990-01-01

    Apparatus for conditioning high voltage pulses from particle accelerators in order to shorten the rise times of the pulses. Flashover switches in the cathode stalk of the transmission line hold off conduction for a determinable period of time, reflecting the early portion of the pulses. Diodes upstream of the switches divert energy into the magnetic and electrostatic storage of the capacitance and inductance inherent to the transmission line until the switches close.

  18. Lines

    ERIC Educational Resources Information Center

    Mires, Peter B.

    2006-01-01

    National Geography Standards for the middle school years generally stress the teaching of latitude and longitude. There are many creative ways to explain the great grid that encircles our planet, but the author has found that students in his college-level geography courses especially enjoy human-interest stories associated with lines of latitude…

  19. Preparation of Power Distribution System for High Penetration of Renewable Energy Part I. Dynamic Voltage Restorer for Voltage Regulation Pat II. Distribution Circuit Modeling and Validation

    NASA Astrophysics Data System (ADS)

    Khoshkbar Sadigh, Arash

    Part I: Dynamic Voltage Restorer In the present power grids, voltage sags are recognized as a serious threat and a frequently occurring power-quality problem and have costly consequence such as sensitive loads tripping and production loss. Consequently, the demand for high power quality and voltage stability becomes a pressing issue. Dynamic voltage restorer (DVR), as a custom power device, is more effective and direct solutions for "restoring" the quality of voltage at its load-side terminals when the quality of voltage at its source-side terminals is disturbed. In the first part of this thesis, a DVR configuration with no need of bulky dc link capacitor or energy storage is proposed. This fact causes to reduce the size of the DVR and increase the reliability of the circuit. In addition, the proposed DVR topology is based on high-frequency isolation transformer resulting in the size reduction of transformer. The proposed DVR circuit, which is suitable for both low- and medium-voltage applications, is based on dc-ac converters connected in series to split the main dc link between the inputs of dc-ac converters. This feature makes it possible to use modular dc-ac converters and utilize low-voltage components in these converters whenever it is required to use DVR in medium-voltage application. The proposed configuration is tested under different conditions of load power factor and grid voltage harmonic. It has been shown that proposed DVR can compensate the voltage sag effectively and protect the sensitive loads. Following the proposition of the DVR topology, a fundamental voltage amplitude detection method which is applicable in both single/three-phase systems for DVR applications is proposed. The advantages of proposed method include application in distorted power grid with no need of any low-pass filter, precise and reliable detection, simple computation and implementation without using a phased locked loop and lookup table. The proposed method has been verified

  20. Fabrication of a flexible Ag-grid transparent electrode using ac based electrohydrodynamic Jet printing

    NASA Astrophysics Data System (ADS)

    Park, Jaehong; Hwang, Jungho

    2014-10-01

    In the dc voltage-applied electrohydrodynamic (EHD) jet printing of metal nanoparticles, the residual charge of droplets deposited on a substrate changes the electrostatic field distribution and interrupts the subsequent printing behaviour, especially for insulating substrates that have slow charge decay rates. In this paper, a sinusoidal ac voltage was used in the EHD jet printing process to switch the charge polarity of droplets containing Ag nanoparticles, thereby neutralizing the charge on a polyethylene terephthalate (PET) substrate. Printed Ag lines with a width of 10 µm were invisible to the naked eye. After sintering lines with 500 µm of line pitch at 180 °C, a grid-type transparent electrode (TE) with a sheet resistance of ˜7 Ω sq-1 and a dc to optical conductivity ratio of ˜300 at ˜84.2% optical transmittance was obtained, values that were superior to previously reported results. In order to evaluate the durability of the TE under bending stresses, the sheet resistance was measured as the number of bending cycles was increased. The sheet resistance of the Ag grid electrode increased only slightly, by less than 20% from its original value, even after 500 cycles. To the best of our knowledge, this is the first time that Ag (invisible) grid TEs have been fabricated on PET substrates by ac voltage applied EHD jet printing.

  1. Border Collision of Three-Phase Voltage-Source Inverter System with Interacting Loads

    NASA Astrophysics Data System (ADS)

    Li, Zhen; Liu, Bin; Li, Yining; Wong, Siu-Chung; Liu, Xiangdong; Huang, Yuehui

    As a commercial interface, three-phase voltage-source inverters (VSI) are commonly equipped for energy conversion to export DC power from most distributed generation (DG) to the AC utility. Not only do voltage-source converters take charge of converting the power to the loads but support the grid voltage at the point of common connection (PCC) as well, which is dependent on the condition of the grid-connected loads. This paper explores the border collision and its interacting mechanism among the VSI, resistive interacting loads and grids, which manifests as the alternating emergence of the inverting and rectifying operations, where the normal operation is terminated and a new one is assumed. Their mutual effect on the power quality under investigation will cause the circuital stability issue and further deteriorate the voltage regulation capability of VSI by dramatically raising the grid voltage harmonics. It is found in a design-oriented view that the border collision operation will be induced within the unsuitable parameter space with respect to transmission lines of AC grid, resistive loads and internal resistance of VSI. The physical phenomenon is also identified by the theoretical analysis. With numerical simulations for various circuit conditions, the corresponding bifurcation boundaries are collected, where the stability of the system is lost via border collision.

  2. Design studies for the Mead-Phoenix 500 kV AC transmission project

    SciTech Connect

    Thallam, R.S.; Lundquist, T.G.; Gerlach, D.W.; Atmuri, S.R.; Selin, D.A.

    1995-10-01

    The Mead-Phoenix 500 kV ac line is 243 miles long and runs parallel to the existing Mead-Liberty 345 kV line. This line is planned for 70% series and 70% shunt compensation; it also incorporates the first application of a 50 kV phase shifting transformer that enables a 1,300 MW transmission capacity. This paper presents the design studies that were undertaken in arriving at the equipment ratings and insulation levels that lead to the equipment specifications. The shunt reactor switching requirements utilizing MOV across the breaker, line switching with line connected arresters and the breaker transient recovery voltage are also dealt with in the paper.

  3. Index-based reactive power compensation scheme for voltage regulation

    NASA Astrophysics Data System (ADS)

    Dike, Damian Obioma

    2008-10-01

    Increasing demand for electrical power arising from deregulation and the restrictions posed to the construction of new transmission lines by environment, socioeconomic, and political issues had led to higher grid loading. Consequently, voltage instability has become a major concern, and reactive power support is vital to enhance transmission grid performance. Improved reactive power support to distressed grid is possible through the application of relatively unfamiliar emerging technologies of "Flexible AC Transmission Systems (FACTS)" devices and "Distributed Energy Resources (DERS)." In addition to these infrastructure issues, a lack of situational awareness by system operators can cause major power outages as evidenced by the August 14, 2003 widespread North American blackout. This and many other recent major outages have highlighted the inadequacies of existing power system indexes. In this work, a novel "Index-based reactive compensation scheme" appropriate for both on-line and off-line computation of grid status has been developed. A new voltage stability index (Ls-index) suitable for long transmission lines was developed, simulated, and compared to the existing two-machine modeled L-index. This showed the effect of long distance power wheeling amongst regional transmission organizations. The dissertation further provided models for index modulated voltage source converters (VSC) and index-based load flow analysis of both FACTS and microgrid interconnected power systems using the Newton-Raphson's load flow model incorporated with multi-FACTS devices. The developed package has been made user-friendly through the embodiment of interactive graphical user interface and implemented on the IEEE 14, 30, and 300 bus systems. The results showed reactive compensation has system wide-effect, provided readily accessible system status indicators, ensured seamless DERs interconnection through new islanding modes and enhanced VSC utilization. These outcomes may contribute

  4. Dynamic voltage-current characteristics for a water jet plasma arc

    SciTech Connect

    Yang Jiaxiang; Lan Sheng; Xu Zuoming

    2008-05-05

    A virtual instrument technology is used to measure arc current, arc voltage, dynamic V-I characteristics, and nonlinear conductance for a cone-shaped water jet plasma arc under ac voltage. Experimental results show that ac arc discharge mainly happens in water vapor evaporated from water when heated. However, due to water's cooling effect and its conductance, arc conductance, reignition voltage, extinguish voltage, and current zero time are very different from those for ac arc discharge in gas work fluid. These can be valuable to further studies on mechanism and characteristics of plasma ac discharge in water, and even in gas work fluid.

  5. A Kalman filtering based control scheme for the improvement of dynamic performance of an AC/DC power system

    NASA Astrophysics Data System (ADS)

    Pecen, Recayi

    In this dissertation, two major accomplishments are achieved. First, the feasibility of a proposed Wyoming to California HVDC system having the ratings of 1000 MW, ±500 kV, 2 kA, 860 miles and 12-pulse bipolar lines is shown for exporting Wyoming's electrical power resources to the heavy loaded western states. The second and the main objective of this dissertation is the development of a Kalman filtering (KF) based control scheme applied to an ac/dc power system. It is shown that the use KF algorithm to estimate some of the system states and utilizing them in a proportional Integral (PI) controller which has a better performance for this specific control scheme have resulted in a better dynamic performance of the proposed system. A set of case studies has shown that the system dynamic performance is improved for most of the contingencies. Ac and dc noisy voltage and current measurements received from the simulated ac/dc power system are sent to the KF estimation algorithm. The noise-separated best estimates of measurable states are computed and sent to a PI controller-based current and firing angle control subsections in order to provide a set of optimum thyristor firing angles for both converter stations during and after contingencies until the normal operation is reached. To evaluate the dynamic performance of the system with the KF algorithm, the model is simulated by a well-known digital simulation package, Electromagnetic Transients DC Program (PSCAD/EMTDC) of Manitoba HVDC Research Center. To apply the KF algorithm, a general, linearized, state-space model of the proposed ac/dc system, appropriate for analyzing both the KF and the electromagnetics transients, is derived first. The derived model enables the representation of an ac power system with two ac sources and one HVDC line with a parallel ac line connecting the two systems. It is shown that system eigenvalues of the discretized system model for a normal operating point are inside the unit circle that

  6. Voltage modulation of propagating spin waves in Fe

    SciTech Connect

    Nawaoka, Kohei; Shiota, Yoichi; Miwa, Shinji; Tamura, Eiiti; Tomita, Hiroyuki; Mizuochi, Norikazu; Shinjo, Teruya; Suzuki, Yoshishige

    2015-05-07

    The effect of a voltage application on propagating spin waves in single-crystalline 5 nm-Fe layer was investigated. Two micro-sized antennas were employed to excite and detect the propagating spin waves. The voltage effect was characterized using AC lock-in technique. As a result, the resonant field of the magnetostatic surface wave in the Fe was clearly modulated by the voltage application. The modulation is attributed to the voltage induced magnetic anisotropy change in ferromagnetic metals.

  7. A Matter of Quantum Voltages

    SciTech Connect

    Sellner, Bernhard; Kathmann, Shawn M.

    2014-11-14

    Voltages inside matter are relevant to crystallization, materials science, biology, catalysis, and aqueous chemistry. Electron holography is able to measure the variation of voltages in matter and modern supercomputers allow the calculation of quantum voltages with practically unlimited spatial and temporal resolution of bulk systems. Of particular interest is the Mean Inner Potential (Vo) - the spatial average of these voltages. Voltages are very sensitive to the distribution of electrons and provide metrics to understand interactions in condensed phases. In the present study, we find excellent agreement with measurements of Vo for vitrified water and salt crystals and demonstrate the impact of covalent and ionic bonding as well as intermolecular/atomic interactions. Furthermore, we predict Vo as well as the fluctuations of these voltages in aqueous NaCl electrolytes and characterize the changes in their behavior as the resolution increases below the size of atoms. This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. Pacific Northwest National Laboratory (PNNL) is a multiprogram national laboratory operated for DOE by Battelle. This research used resources of the National Energy Research Scientific Computing Center, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

  8. System and method for determining stator winding resistance in an AC motor using motor drives

    DOEpatents

    Lu, Bin; Habetler, Thomas G; Zhang, Pinjia

    2013-02-26

    A system and method for determining the stator winding resistance of AC motors is provided. The system includes an AC motor drive having an input connectable to an AC source and an output connectable to an input terminal of an AC motor, a pulse width modulation (PWM) converter having switches therein to control current flow and terminal voltages in the AC motor, and a control system connected to the PWM converter. The control system generates a command signal to cause the PWM converter to control an output of the AC motor drive corresponding to an input to the AC motor, selectively generates a modified command signal to cause the PWM converter to inject a DC signal into the output of the AC motor drive, and determines a stator winding resistance of the AC motor based on the DC signal of at least one of the voltage and current.

  9. METALLICITIES OF EMISSION-LINE GALAXIES FROM HST ACS PEARS AND HST WFC3 ERS GRISM SPECTROSCOPY AT 0.6 < z < 2.4

    SciTech Connect

    Xia Lifang; Malhotra, Sangeeta; Rhoads, James; Cohen, Seth; Windhorst, Rogier A.; Pirzkal, Nor; Straughn, Amber; Finkelstein, Steven; Kuntschner, Harald; Kuemmel, Martin; Walsh, Jeremy; O'Connell, Robert

    2012-07-15

    Galaxies selected on the basis of their emission-line strength show low metallicities, regardless of their redshifts. We conclude this from a sample of faint galaxies at redshifts between 0.6 < z < 2.4, selected by their prominent emission lines in low-resolution grism spectra in the optical with the Advanced Camera for Surveys on the Hubble Space Telescope and in the near-infrared using Wide-Field Camera 3. Using a sample of 11 emission-line galaxies at 0.6 < z < 2.4 with luminosities of -22 {approx}< M{sub B} {approx}< -19 which have [O II], H{beta}, and [O III] line flux measurements from the combination of two grism spectral surveys, we use the R23 method to derive the gas-phase oxygen abundances: 7.5 < 12 + log (O/H) < 8.5. The galaxy stellar masses are derived using Bayesian-based Markov Chain Monte Carlo ({pi}MC{sup 2}) fitting of their spectral energy distribution, and span the mass range 8.1 < log (M{sub *}/M{sub Sun} ) < 10.1. These galaxies show mass-metallicity (M-Z) and luminosity-metallicity (L-Z) relations, which are offset by -0.6 dex in metallicity at given absolute magnitude and stellar mass relative to the local Sloan Digital Sky Survey galaxies, as well as continuum-selected DEEP2 samples at similar redshifts. The emission-line-selected galaxies most resemble the local 'green peas' galaxies and Ly{alpha} galaxies at z {approx_equal} 0.3 and z {approx_equal} 2.3 in the M-Z and L-Z relations and their morphologies. The G - M{sub 20} morphology analysis shows that 10 out of 11 show disturbed morphology, even as the star-forming regions are compact. These galaxies may be intrinsically metal poor, being at early stages of formation, or the low metallicities may be due to gas infall and accretion due to mergers.

  10. Hybrid particle traps and conditioning procedure for gas insulated transmission lines

    DOEpatents

    Dale, Steinar J.; Cookson, Alan H.

    1982-01-01

    A gas insulated transmission line includes an outer sheath, an inner condor within the outer sheath, insulating supports supporting the inner conductor within the outer sheath, and an insulating gas electrically insulating the inner conductor from the outer sheath. An apertured particle trapping ring is disposed within the outer sheath, and the trapping ring has a pair of dielectric members secured at each longitudinal end thereof, with the dielectric members extending outwardly from the trapping ring along an arc. A support sheet having an adhesive coating thereon is secured to the trapping ring and disposed on the outer sheath within the low field region formed between the trapping ring and the outer sheath. A conditioning method used to condition the transmission line prior to activation in service comprises applying an AC voltage to the inner conductor in a plurality of voltage-time steps, with the voltage-time steps increasing in voltage magnitude while decreasing in time duration.

  11. Recovery of consciousness in broilers following combined dc and ac stunning

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Broilers in the United States are typically electrically stunned using low voltage-high frequency pulsed DC water bath stunners and in the European Union broilers are electrocuted using high voltage-low frequency AC. DC stunned broilers regain consciousness in the absence of exsanguination and AC st...

  12. Voltage Controller

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Power Efficiency Corporation, specifically formed to manufacture and develop products from NASA technology, has a license to a three-phase power factor controller originally developed by Frank Nola, an engineer at Marshall Space Flight Center. Power Efficiency and two major distributors, Performance Control and Edison Power Technologies, use the electronic control boards to assemble three different motor controllers: Power Commander, Performance Controller, and Energy Master. The company Power Factor Controller reduces excessive energy waste in AC induction motors. It is used in industries and applications where motors operate under variable loads, including elevators and escalators, machine tools, intake and exhaust fans, oil wells, conveyors, pumps, die casting, and compressors. Customer lists include companies such as May Department Stores, Caesars Atlantic City, Ford Motors, and American Axle.

  13. Distance to high-voltage power lines and risk of childhood leukemia--an analysis of confounding by and interaction with other potential risk factors.

    PubMed

    Pedersen, Camilla; Bräuner, Elvira V; Rod, Naja H; Albieri, Vanna; Andersen, Claus E; Ulbak, Kaare; Hertel, Ole; Johansen, Christoffer; Schüz, Joachim; Raaschou-Nielsen, Ole

    2014-01-01

    We investigated whether there is an interaction between distance from residence at birth to nearest power line and domestic radon and traffic-related air pollution, respectively, in relation to childhood leukemia risk. Further, we investigated whether adjusting for potential confounders alters the association between distance to nearest power line and childhood leukemia. We included 1024 cases aged <15, diagnosed with leukemia during 1968-1991, from the Danish Cancer Registry and 2048 controls randomly selected from the Danish childhood population and individually matched by gender and year of birth. We used geographical information systems to determine the distance between residence at birth and the nearest 132-400 kV overhead power line. Concentrations of domestic radon and traffic-related air pollution (NOx at the front door) were estimated using validated models. We found a statistically significant interaction between distance to nearest power line and domestic radon regarding risk of childhood leukemia (p = 0.01) when using the median radon level as cut-off point but not when using the 75th percentile (p = 0.90). We found no evidence of an interaction between distance to nearest power line and traffic-related air pollution (p = 0.73). We found almost no change in the estimated association between distance to power line and risk of childhood leukemia when adjusting for socioeconomic status of the municipality, urbanization, maternal age, birth order, domestic radon and traffic-related air pollution. The statistically significant interaction between distance to nearest power line and domestic radon was based on few exposed cases and controls and sensitive to the choice of exposure categorization and might, therefore, be due to chance. PMID:25259740

  14. A single-phase embedded Z-source DC-AC inverter.

    PubMed

    Kim, Se-Jin; Lim, Young-Cheol

    2014-01-01

    In the conventional DC-AC inverter consisting of two DC-DC converters with unipolar output capacitors, the output capacitor voltages of the DC-DC converters must be higher than the DC input voltage. To overcome this weakness, this paper proposes a single-phase DC-AC inverter consisting of two embedded Z-source converters with bipolar output capacitors. The proposed inverter is composed of two embedded Z-source converters with a common DC source and output AC load. Though the output capacitor voltages of the converters are relatively low compared to those of a conventional inverter, an equivalent level of AC output voltages can be obtained. Moreover, by controlling the output capacitor voltages asymmetrically, the AC output voltage of the proposed inverter can be higher than the DC input voltage. To verify the validity of the proposed inverter, experiments were performed with a DC source voltage of 38 V. By controlling the output capacitor voltages of the converters symmetrically or asymmetrically, the proposed inverter can produce sinusoidal AC output voltages. The experiments show that efficiencies of up to 95% and 97% can be achieved with the proposed inverter using symmetric and asymmetric control, respectively.

  15. A Single-Phase Embedded Z-Source DC-AC Inverter

    PubMed Central

    Kim, Se-Jin; Lim, Young-Cheol

    2014-01-01

    In the conventional DC-AC inverter consisting of two DC-DC converters with unipolar output capacitors, the output capacitor voltages of the DC-DC converters must be higher than the DC input voltage. To overcome this weakness, this paper proposes a single-phase DC-AC inverter consisting of two embedded Z-source converters with bipolar output capacitors. The proposed inverter is composed of two embedded Z-source converters with a common DC source and output AC load. Though the output capacitor voltages of the converters are relatively low compared to those of a conventional inverter, an equivalent level of AC output voltages can be obtained. Moreover, by controlling the output capacitor voltages asymmetrically, the AC output voltage of the proposed inverter can be higher than the DC input voltage. To verify the validity of the proposed inverter, experiments were performed with a DC source voltage of 38 V. By controlling the output capacitor voltages of the converters symmetrically or asymmetrically, the proposed inverter can produce sinusoidal AC output voltages. The experiments show that efficiencies of up to 95% and 97% can be achieved with the proposed inverter using symmetric and asymmetric control, respectively. PMID:25133241

  16. A single-phase embedded Z-source DC-AC inverter.

    PubMed

    Kim, Se-Jin; Lim, Young-Cheol

    2014-01-01

    In the conventional DC-AC inverter consisting of two DC-DC converters with unipolar output capacitors, the output capacitor voltages of the DC-DC converters must be higher than the DC input voltage. To overcome this weakness, this paper proposes a single-phase DC-AC inverter consisting of two embedded Z-source converters with bipolar output capacitors. The proposed inverter is composed of two embedded Z-source converters with a common DC source and output AC load. Though the output capacitor voltages of the converters are relatively low compared to those of a conventional inverter, an equivalent level of AC output voltages can be obtained. Moreover, by controlling the output capacitor voltages asymmetrically, the AC output voltage of the proposed inverter can be higher than the DC input voltage. To verify the validity of the proposed inverter, experiments were performed with a DC source voltage of 38 V. By controlling the output capacitor voltages of the converters symmetrically or asymmetrically, the proposed inverter can produce sinusoidal AC output voltages. The experiments show that efficiencies of up to 95% and 97% can be achieved with the proposed inverter using symmetric and asymmetric control, respectively. PMID:25133241

  17. Response of dairy cattle to transient voltages and magnetic fields

    SciTech Connect

    Reinemann, D.J.; Laughlin, N.K.; Stetson, L.E.

    1995-07-01

    Stray voltages in dairy facilities have been studied since the 1970`s. Previous research using steady-state ac and dc voltages has defined cow-contact voltage levels which may cause behavior and associated production problems. This research was designed to address concerns over possible effects of transient voltages and magnetic fields on dairy cows. Dairy cows response to transient voltages and magnetic fields was measured. The waveforms of the transient voltages applied were: 5 cycles of 60-Hz ac with a total pulse time of 83 ms, 1 cycle of 60-Hz ac with a total pulse time of 16 ms, and 1 cycle of an ac square wave (spiking positive and negative) of 2-ms duration. Alternating magnetic fields were produced by passing 60-Hz ac fundamental frequency with 2nd and 3rd harmonic and random noise components in metal structures around the cows. The maximum magnetic field associated with this current flow was in excess of 4 G. A wide range of sensitivity to transient voltages was observed among cows. Response levels from 24 cows to each transient exposure were normally distributed. No responses to magnetic fields were observed.

  18. Low power, scalable multichannel high voltage controller

    DOEpatents

    Stamps, James Frederick; Crocker, Robert Ward; Yee, Daniel Dadwa; Dils, David Wright

    2006-03-14

    A low voltage control circuit is provided for individually controlling high voltage power provided over bus lines to a multitude of interconnected loads. An example of a load is a drive for capillary channels in a microfluidic system. Control is distributed from a central high voltage circuit, rather than using a number of large expensive central high voltage circuits to enable reducing circuit size and cost. Voltage is distributed to each individual load and controlled using a number of high voltage controller channel switches connected to high voltage bus lines. The channel switches each include complementary pull up and pull down photo isolator relays with photo isolator switching controlled from the central high voltage circuit to provide a desired bus line voltage. Switching of the photo isolator relays is further controlled in each channel switch using feedback from a resistor divider circuit to maintain the bus voltage swing within desired limits. Current sensing is provided using a switched resistive load in each channel switch, with switching of the resistive loads controlled from the central high voltage circuit.

  19. Low power, scalable multichannel high voltage controller

    DOEpatents

    Stamps, James Frederick; Crocker, Robert Ward; Yee, Daniel Dadwa; Dils, David Wright

    2008-03-25

    A low voltage control circuit is provided for individually controlling high voltage power provided over bus lines to a multitude of interconnected loads. An example of a load is a drive for capillary channels in a microfluidic system. Control is distributed from a central high voltage circuit, rather than using a number of large expensive central high voltage circuits to enable reducing circuit size and cost. Voltage is distributed to each individual load and controlled using a number of high voltage controller channel switches connected to high voltage bus lines. The channel switches each include complementary pull up and pull down photo isolator relays with photo isolator switching controlled from the central high voltage circuit to provide a desired bus line voltage. Switching of the photo isolator relays is further controlled in each channel switch using feedback from a resistor divider circuit to maintain the bus voltage swing within desired limits. Current sensing is provided using a switched resistive load in each channel switch, with switching of the resistive loads controlled from the central high voltage circuit.

  20. A dry-cooled AC quantum voltmeter

    NASA Astrophysics Data System (ADS)

    Schubert, M.; Starkloff, M.; Peiselt, K.; Anders, S.; Knipper, R.; Lee, J.; Behr, R.; Palafox, L.; Böck, A. C.; Schaidhammer, L.; Fleischmann, P. M.; Meyer, H.-G.

    2016-10-01

    The paper describes a dry-cooled AC quantum voltmeter system operated up to kilohertz frequencies and 7 V rms. A 10 V programmable Josephson voltage standard (PJVS) array was installed on a pulse tube cooler (PTC) driven with a 4 kW air-cooled compressor. The operating margins at 70 GHz frequencies were investigated in detail and found to exceed 1 mA Shapiro step width. A key factor for the successful chip operation was the low on-chip power consumption of 65 mW in total. A thermal interface between PJVS chip and PTC cold stage was used to avoid a significant chip overheating. By installing the cryocooled PJVS array into an AC quantum voltmeter setup, several calibration measurements of dc standards and calibrator ac voltages up to 2 kHz frequencies were carried out to demonstrate the full functionality. The results are discussed and compared to systems with standard liquid helium cooling. For dc voltages, a direct comparison measurement between the dry-cooled AC quantum voltmeter and a liquid-helium based 10 V PJVS shows an agreement better than 1 part in 1010.

  1. Ac-dc converter firing error detection

    SciTech Connect

    Gould, O.L.

    1996-07-15

    Each of the twelve Booster Main Magnet Power Supply modules consist of two three-phase, full-wave rectifier bridges in series to provide a 560 VDC maximum output. The harmonic contents of the twelve-pulse ac-dc converter output are multiples of the 60 Hz ac power input, with a predominant 720 Hz signal greater than 14 dB in magnitude above the closest harmonic components at maximum output. The 720 Hz harmonic is typically greater than 20 dB below the 500 VDC output signal under normal operation. Extracting specific harmonics from the rectifier output signal of a 6, 12, or 24 pulse ac-dc converter allows the detection of SCR firing angle errors or complete misfires. A bandpass filter provides the input signal to a frequency-to-voltage converter. Comparing the output of the frequency-to-voltage converter to a reference voltage level provides an indication of the magnitude of the harmonics in the ac-dc converter output signal.

  2. Structure of the Surface Streamers of an AC Barrier Corona in Argon

    SciTech Connect

    Akishev, Yu.S.; Aponin, G.I.; Karal'nik, V.B.; Monich, A.E.; Trushkin, N.I.

    2004-12-15

    Results are presented from experimental studies of the structure of an ac surface discharge excited by a metal needle over a plane dielectric surface. A barrier corona discharge was ignited in atmospheric-pressure argon at frequencies of the applied sinusoidal voltage from 50 Hz to 30 kHz. In experiments, the area of a dielectric covered with the discharge plasma increased with applied voltage. The discharge structure in diffuse and streamer modes was recorded using a digital camera and a high-speed image tube operating in a frame mode. It is found that, in the positive and negative half-periods of the applied voltage, the structure of the surface discharge is substantially different. The statistical characteristics of the branching surface streamers in the positive and negative half-periods are determined as functions of the voltage frequency. The most intense lines in the emission spectrum of the barrier corona are determined for both half-periods. The correlation between the dynamics of the emission intensity and the dynamics of the discharge current and voltage is investigated.

  3. Fabrication of alumina films with laminated structures by ac anodization

    NASA Astrophysics Data System (ADS)

    Segawa, Hiroyo; Okano, Hironaga; Wada, Kenji; Inoue, Satoru

    2014-02-01

    Anodization techniques by alternating current (ac) are introduced in this review. By using ac anodization, laminated alumina films are fabricated. Different types of alumina films consisting of 50-200 nm layers were obtained by varying both the ac power supply and the electrolyte. The total film thickness increased with an increase in the total charge transferred. The thickness of the individual layers increased with the ac voltage; however, the anodization time had little effect on the film thickness. The laminated alumina films resembled the nacre structure of shells, and the different morphologies exhibited by bivalves and spiral shells could be replicated by controlling the rate of increase of the applied potentials.

  4. Effect of hepatitis B virus infection on trophoblast cell line (HTR-8/SVneo) and choriocarcinoma cell line (JEG3) is linked to CD133-2 (AC141) expression.

    PubMed

    Cui, Hong; Chen, Jing; Na, Quan

    2016-01-01

    Mother-to-infant transmission of hepatitis B virus (HBV) plays an important role in the chronic carrier state in China. In our studies, the response of trophoblast cell and choriocarcinoma cell to HBV infection regarding the expression of CD133-2 (AC141) was evaluated. Western blot and RT-PCR showed that a high level of CD133-2 protein and mRNA in HTR-8/SVneo cells, but a low level in JEG-3 cells. Lower proliferation and mobility, and higher apoptosis were observed in HTR-8/SVneo cells and JEG-3-CD133-2(+) cells after HBV infection than those in HTR-8-CD133-2(-) cells and JEG-3 cells. Our main finding is that CD133-negative cells (HTR-8-CD133-2(-) and JEG-3) are prone to HBV infection. In the last, our data indicated that the activation of Smad signaling pathway and the induction of epithelial-mesenchymal transition (EMT) in CD133-negative cells after HBV infection. In summary, our study demonstrated that CD133 is a key factor that mediated HBV infection to trophoblast cell and choriocarcinoma cell. PMID:27508045

  5. Non-contact current and voltage sensor

    SciTech Connect

    Carpenter, Gary D; El-Essawy, Wael; Ferreira, Alexandre Peixoto; Keller, Thomas Walter; Rubio, Juan C; Schappert, Michael A

    2014-03-25

    A detachable current and voltage sensor provides an isolated and convenient device to measure current passing through a conductor such as an AC branch circuit wire, as well as providing an indication of an electrostatic potential on the wire, which can be used to indicate the phase of the voltage on the wire, and optionally a magnitude of the voltage. The device includes a housing that contains the current and voltage sensors, which may be a ferrite cylinder with a hall effect sensor disposed in a gap along the circumference to measure current, or alternative a winding provided through the cylinder along its axis and a capacitive plate or wire disposed adjacent to, or within, the ferrite cylinder to provide the indication of the voltage.

  6. Methods, systems and apparatus for controlling operation of two alternating current (AC) machines

    DOEpatents

    Gallegos-Lopez, Gabriel; Nagashima, James M.; Perisic, Milun; Hiti, Silva

    2012-02-14

    A system is provided for controlling two AC machines. The system comprises a DC input voltage source that provides a DC input voltage, a voltage boost command control module (VBCCM), a five-phase PWM inverter module coupled to the two AC machines, and a boost converter coupled to the inverter module and the DC input voltage source. The boost converter is designed to supply a new DC input voltage to the inverter module having a value that is greater than or equal to a value of the DC input voltage. The VBCCM generates a boost command signal (BCS) based on modulation indexes from the two AC machines. The BCS controls the boost converter such that the boost converter generates the new DC input voltage in response to the BCS. When the two AC machines require additional voltage that exceeds the DC input voltage required to meet a combined target mechanical power required by the two AC machines, the BCS controls the boost converter to drive the new DC input voltage generated by the boost converter to a value greater than the DC input voltage.

  7. Metallicities of Emission-Line Galaxies from HST ACS PEARS and HST WFC3 ERS Grism Spectroscopy at 0.6 is less than z is less than 2.4

    NASA Technical Reports Server (NTRS)

    Xia, Lifang; Malhotra, Sangetta; Rhoads, James; Pirzkal, Nor; Straughn, Amber; Finkelstein, Steven; Cohen, Seth; Kuntschner, Harald; Walsh, Jeremy; Windhorst, Rogier A.; O'Connell, Robert; Kuemmel, Martin

    2012-01-01

    Galaxies selected on the basis of their emission line strength. show low metallicities, regardless of their redshifts. We conclude this from a sample of faint galaxies at redshifts between 0.6 < z < 2.4, selected by their prominent emission lines in low resolution grism spectra in the optiCa.i with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST) and in the near-infrared using Wide-Field Camera 3 (WFC3). Using a sample of 11 emission line galaxies (ELGs) at 0.6 < z < 2.4 with luminosities of -22 approx < MB approx -19 which have [OII], H-Beta, and [OIII] line flux measurements from the combination of two grism spectral surveys, we use the R23 method to derive the gas-phase oxygen abundances: 7.5 <12+log(0/H)<8.5. The galaxy stellar masses are derived using Bayesian based Markov Chain Monte Carlo (pi MC(exp 2)) fitting of their Spectral Energy Distribution (SED), and span the mass range 8.1 < log(M(stellar)/M(solar)) < 10.1. These galaxies show a mass-metal1icity (M-L) and Luminosity-Metallicity (LZ) relation, which is offset by -line selected galaxies most resemble the local "green peas" galaxies and Lyman-alpha galaxies at z approx = 0.3 and z approx = 2.3 in the M-Z and L-Z relations and their morphologies. The G - M(sub 20) morphology analysis shows that 10 out of 11 show disturbed morphology, even as the star-forming regions are compact. These galaxies may be intrinsically metal poor, being at early stages of formation, or the low metallicities may be due to gas infall and accretion due to mergers.

  8. Diagnostics of AC excited Atmospheric Pressure Plasma Jet with He for Biomedical Applications

    NASA Astrophysics Data System (ADS)

    Hori, Masaru; Takeda, Keigo; Kumakura, Takumi; Ishikawa, Kenji; Tanaka, Hiromasa; Kondo, Hiroki; Sekine, Makoto; Nakai, Yoshihiro

    2014-10-01

    Atmospheric pressure plasma jets (APPJ) are frequently used for biomedical applications. Reactive species generated by the APPJ play important roles for treatments of biomedical samples. Therefore, high density APPJ sources are required to realize the high performance. Our group has developed AC excited Ar APPJ with electron density as high as 1015 cm-3, and realized the selective killing of cancer cells and the inactivate spores of Penicillium digitatum. Recently, a new spot-size AC excited APPJ with He gas have been developed. In this study, the He APPJ was characterized by using spectroscopy. The plasma was discharged at a He flow rate of 5 slm and a discharge voltage of AC 9 kV. Gas temperature and electron density of the APPJ were measured by optical emission spectroscopy. From theoretical fitting of 2nd positive system of N2 emission (380.4 nm) and Stark broadening of Balmer β line of H atom (486.1 nm), the gas temperature and the electron density was estimated to be 299 K and 3.4. × 1015 cm-3. The AC excited He APPJ has a potential to realize high density with room temperature and become a very powerful tool for biomedical applications.

  9. Helicopter-based live-line work. Volume 1, Helicopter platform work between phases: Final report

    SciTech Connect

    Gela, G.

    1993-06-01

    This report presents experimental data on tests of a configuration consisting of a helicopter between two energized phases (for AC and switching surge) or poles (for DC). The configuration is that related to live-line work from a hovering helicopter. The McDonnell Douglas 500 Series helicopter was used for the tests. All tests were performed with phase-to-phase, or pole-to-pole energization. For AC tests, proper relationship between the phase-to-ground voltages and the phase-to-phase voltage was maintained by energizing the experimental setup from a balanced 3-{phi} AC source. For DC tests, one pole was energized with positive DC voltage to ground, while the other pole was energized with negative DC voltage to ground. For switching surge tests, a surge of positive polarity and a specific peak voltage magnitude was applied to one phase while a surge of negative polarity and the same peak voltage Magnitude was simultaneously applied to the other phase, resulting in {alpha} = 0.5 ({alpha} is the ratio between negative and total surge). In the research program, four conditions were investigated, namely helicopter operating versus not operating, and helicopter bonded to one phase or pole versus not bonded. Results from this research show effects of the rotating main rotor blade of the helicopter, effect of the position of the electrically floating helicopter in the phase-to-phase or pole-to-pole gap, effects of the mannequin, importance of the polarity of the DC poles and switching surges, and effects of inclement weather such as rain. The overall conclusion of this research is that the phase-to-phase or pole-to-pole spacings that cause sparkover with the helicopter between phases (poles) were always significantly smaller than the typical spacings on actual existing overhead transmission lines of the corresponding voltage rating.

  10. AC Loss Measurements on a 2G YBCO Coil

    SciTech Connect

    Rey, Christopher M; Duckworth, Robert C; Schwenterly, S W

    2011-01-01

    The Oak Ridge National Laboratory (ORNL) is collaborating with Waukesha Electric Systems (WES) to continue development of HTS power transformers. For compatibility with the existing power grid, a commercially viable HTS transformer will have to operate at high voltages in the range of 138 kV and above, and will have to withstand 550-kV impulse voltages as well. Second-generation (2G) YBCO coated conductors will be required for an economically-competitive design. In order to adequately size the refrigeration system for these transformers, the ac loss of these HTS coils must be characterized. Electrical AC loss measurements were conducted on a prototype high voltage (HV) coil with co-wound stainless steel at 60 Hz in a liquid nitrogen bath using a lock-in amplifier technique. The prototype HV coil consisted of 26 continuous (without splice) single pancake coils concentrically centered on a stainless steel former. For ac loss measurement purposes, voltage tap pairs were soldered across each set of two single pancake coils so that a total of 13 separate voltage measurements could be made across the entire length of the coil. AC loss measurements were taken as a function of ac excitation current. Results show that the loss is primarily concentrated at the ends of the coil where the operating fraction of critical current is the highest and show a distinct difference in current scaling of the losses between low current and high current regimes.

  11. High voltage isolation transformer

    NASA Technical Reports Server (NTRS)

    Clatterbuck, C. H.; Ruitberg, A. P. (Inventor)

    1985-01-01

    A high voltage isolation transformer is provided with primary and secondary coils separated by discrete electrostatic shields from the surfaces of insulating spools on which the coils are wound. The electrostatic shields are formed by coatings of a compound with a low electrical conductivity which completely encase the coils and adhere to the surfaces of the insulating spools adjacent to the coils. Coatings of the compound also line axial bores of the spools, thereby forming electrostatic shields separating the spools from legs of a ferromagnetic core extending through the bores. The transformer is able to isolate a high constant potential applied to one of its coils, without the occurrence of sparking or corona, by coupling the coatings, lining the axial bores to the ferromagnetic core and by coupling one terminal of each coil to the respective coating encasing the coil.

  12. High Voltage Seismic Generator

    NASA Astrophysics Data System (ADS)

    Bogacz, Adrian; Pala, Damian; Knafel, Marcin

    2015-04-01

    This contribution describes the preliminary result of annual cooperation of three student research groups from AGH UST in Krakow, Poland. The aim of this cooperation was to develop and construct a high voltage seismic wave generator. Constructed device uses a high-energy electrical discharge to generate seismic wave in ground. This type of device can be applied in several different methods of seismic measurement, but because of its limited power it is mainly dedicated for engineering geophysics. The source operates on a basic physical principles. The energy is stored in capacitor bank, which is charged by two stage low to high voltage converter. Stored energy is then released in very short time through high voltage thyristor in spark gap. The whole appliance is powered from li-ion battery and controlled by ATmega microcontroller. It is possible to construct larger and more powerful device. In this contribution the structure of device with technical specifications is resented. As a part of the investigation the prototype was built and series of experiments conducted. System parameter was measured, on this basis specification of elements for the final device were chosen. First stage of the project was successful. It was possible to efficiently generate seismic waves with constructed device. Then the field test was conducted. Spark gap wasplaced in shallowborehole(0.5 m) filled with salt water. Geophones were placed on the ground in straight line. The comparison of signal registered with hammer source and sparker source was made. The results of the test measurements are presented and discussed. Analysis of the collected data shows that characteristic of generated seismic signal is very promising, thus confirms possibility of practical application of the new high voltage generator. The biggest advantage of presented device after signal characteristics is its size which is 0.5 x 0.25 x 0.2 m and weight approximately 7 kg. This features with small li-ion battery makes

  13. Preparation of Power Distribution System for High Penetration of Renewable Energy Part I. Dynamic Voltage Restorer for Voltage Regulation Pat II. Distribution Circuit Modeling and Validation

    NASA Astrophysics Data System (ADS)

    Khoshkbar Sadigh, Arash

    Part I: Dynamic Voltage Restorer In the present power grids, voltage sags are recognized as a serious threat and a frequently occurring power-quality problem and have costly consequence such as sensitive loads tripping and production loss. Consequently, the demand for high power quality and voltage stability becomes a pressing issue. Dynamic voltage restorer (DVR), as a custom power device, is more effective and direct solutions for "restoring" the quality of voltage at its load-side terminals when the quality of voltage at its source-side terminals is disturbed. In the first part of this thesis, a DVR configuration with no need of bulky dc link capacitor or energy storage is proposed. This fact causes to reduce the size of the DVR and increase the reliability of the circuit. In addition, the proposed DVR topology is based on high-frequency isolation transformer resulting in the size reduction of transformer. The proposed DVR circuit, which is suitable for both low- and medium-voltage applications, is based on dc-ac converters connected in series to split the main dc link between the inputs of dc-ac converters. This feature makes it possible to use modular dc-ac converters and utilize low-voltage components in these converters whenever it is required to use DVR in medium-voltage application. The proposed configuration is tested under different conditions of load power factor and grid voltage harmonic. It has been shown that proposed DVR can compensate the voltage sag effectively and protect the sensitive loads. Following the proposition of the DVR topology, a fundamental voltage amplitude detection method which is applicable in both single/three-phase systems for DVR applications is proposed. The advantages of proposed method include application in distorted power grid with no need of any low-pass filter, precise and reliable detection, simple computation and implementation without using a phased locked loop and lookup table. The proposed method has been verified

  14. Programmable high voltage power supply with regulation confined to the high voltage section

    NASA Technical Reports Server (NTRS)

    Castell, Karen D. (Inventor); Ruitberg, Arthur P. (Inventor)

    1994-01-01

    A high voltage power supply in a dc-dc converter configuration includes a pre-regulator which filters and regulates the dc input and drives an oscillator which applies, in turn, a low voltage ac signal to the low side of a step-up high voltage transformer. The high voltage side of the transformer drives a voltage multiplier which provides a stepped up dc voltage to an output filter. The output voltage is sensed by a feedback network which then controls a regulator. Both the input and output of the regulator are on the high voltage side, avoiding isolation problems. The regulator furnishes a portion of the drive to the voltage multiplier, avoiding having a regulator in series with the load with its attendant, relatively high power losses. This power supply is highly regulated, has low power consumption, a low parts count and may be manufactured at low cost. The power supply has a programmability feature that allows for the selection of a large range of output voltages.

  15. Programmable high voltage power supply with regulation confined to the high voltage section

    NASA Astrophysics Data System (ADS)

    Castell, Karen D.; Ruitberg, Arthur P.

    1994-11-01

    A high voltage power supply in a dc-dc converter configuration includes a pre-regulator which filters and regulates the dc input and drives an oscillator which applies, in turn, a low voltage ac signal to the low side of a step-up high voltage transformer. The high voltage side of the transformer drives a voltage multiplier which provides a stepped up dc voltage to an output filter. The output voltage is sensed by a feedback network which then controls a regulator. Both the input and output of the regulator are on the high voltage side, avoiding isolation problems. The regulator furnishes a portion of the drive to the voltage multiplier, avoiding having a regulator in series with the load with its attendant, relatively high power losses. This power supply is highly regulated, has low power consumption, a low parts count and may be manufactured at low cost. The power supply has a programmability feature that allows for the selection of a large range of output voltages.

  16. Capacitively coupled RF voltage probe having optimized flux linkage

    DOEpatents

    Moore, James A.; Sparks, Dennis O.

    1999-02-02

    An RF sensor having a novel current sensing probe and a voltage sensing probe to measure voltage and current. The current sensor is disposed in a transmission line to link all of the flux generated by the flowing current in order to obtain an accurate measurement. The voltage sensor is a flat plate which operates as a capacitive plate to sense voltage on a center conductor of the transmission line, in which the measured voltage is obtained across a resistance leg of a R-C differentiator circuit formed by the characteristic impedance of a connecting transmission line and a capacitance of the plate, which is positioned proximal to the center conductor.

  17. ACS: ALMA Common Software

    NASA Astrophysics Data System (ADS)

    Chiozzi, Gianluca; Šekoranja, Matej

    2013-02-01

    ALMA Common Software (ACS) provides a software infrastructure common to all ALMA partners and consists of a documented collection of common patterns and components which implement those patterns. The heart of ACS is based on a distributed Component-Container model, with ACS Components implemented as CORBA objects in any of the supported programming languages. ACS provides common CORBA-based services such as logging, error and alarm management, configuration database and lifecycle management. Although designed for ALMA, ACS can and is being used in other control systems and distributed software projects, since it implements proven design patterns using state of the art, reliable technology. It also allows, through the use of well-known standard constructs and components, that other team members whom are not authors of ACS easily understand the architecture of software modules, making maintenance affordable even on a very large project.

  18. Detonator comprising a nonlinear transmission line

    SciTech Connect

    Elizondo-Decanini, Juan M

    2014-12-30

    Detonators are described herein. In a general embodiment, the detonator includes a nonlinear transmission line that has a variable capacitance. Capacitance of the nonlinear transmission line is a function of voltage on the nonlinear transmission line. The nonlinear transmission line receives a voltage pulse from a voltage source and compresses the voltage pulse to generate a trigger signal. Compressing the voltage pulse includes increasing amplitude of the voltage pulse and decreasing length of the voltage pulse in time. An igniter receives the trigger signal and detonates an explosive responsive to receipt of the trigger signal.

  19. Calculation of the ac to dc resistance ratio of conductive nonmagnetic straight conductors by applying FEM simulations

    NASA Astrophysics Data System (ADS)

    Riba, Jordi-Roger

    2015-09-01

    This paper analyzes the skin and proximity effects in different conductive nonmagnetic straight conductor configurations subjected to applied alternating currents and voltages. These effects have important consequences, including a rise of the ac resistance, which in turn increases power loss, thus limiting the rating for the conductor. Alternating current (ac) resistance is important in power conductors and bus bars for line frequency applications, as well as in smaller conductors for high frequency applications. Despite the importance of this topic, it is not usually analyzed in detail in undergraduate and even in graduate studies. To address this, this paper compares the results provided by available exact formulas for simple geometries with those obtained by means of two-dimensional finite element method (FEM) simulations and experimental results. The paper also shows that FEM results are very accurate and more general than those provided by the formulas, since FEM models can be applied in a wide range of electrical frequencies and configurations.

  20. Heterologous expression and functional analysis of rat Nav1.8 (SNS) voltage-gated sodium channels in the dorsal root ganglion neuroblastoma cell line ND7-23.

    PubMed

    John, Victoria H; Main, Martin J; Powell, Andrew J; Gladwell, Zoe M; Hick, Caroline; Sidhu, Harjeet S; Clare, Jeff J; Tate, Simon; Trezise, Derek J

    2004-03-01

    The voltage-gated sodium channel NaV1.8 (SNS, PN3) is thought to be a molecular correlate of the dorsal root ganglion (DRG) tetrodotoxin resistant (TTX-R) Na+ current. TTX-R/NaV1.8 is an attractive therapeutic drug target for inflammatory and neuropathic pain on the basis of its specific distribution in sensory neurones and its modulation by inflammatory mediators. However, detailed analysis of recombinant NaV1.8 has been hampered by difficulties in stably expressing the functional protein in mammalian cells. Here, we show stable expression and functional analysis of rat NaV1.8 (rNaV1.8) in the rat DRG/mouse N18Tg2 neuroblastoma hybridoma cell line ND7-23. Rat NaV1.8 Na+ currents were recorded (789 +/- 89 pA, n=62, over 20-cell passages) that qualitatively resembled DRG TTX-R in terms of gating kinetics and voltage-dependence of activation and inactivation. The local anaesthetic drug tetracaine produced tonic inhibition of rNaV1.8 (mean IC50 value 12.5 microM) and in repeated gating paradigms (2-10 Hz) also showed frequency-dependent block. There was a correlation between the ability of several analogues of the anticonvulsant/analgesic compound lamotrigine to inhibit TTX-R and rNaV1.8 (r=0.72, P<0.001). RT-PCR analysis of wild type ND7-23 cells revealed endogenous expression of the beta1 and beta3 accessory Na+ channel subunits-the possibility that the presence of these subunits assists and stabilises expression of rNaV1.8 is discussed. We conclude that the neuroblastoma ND7-23 cell line is a suitable heterologous expression system for rNaV1.8 Na+ channels in that it allows stable expression of a channel with biophysical properties that closely resemble the native TTX-R currents in DRG neurones. This reagent will prove useful in the search for pharmacological inhibitors of rNaV1.8 as novel analgesics. PMID:14975698

  1. ac electroosmosis in rectangular microchannels.

    PubMed

    Campisi, Michele; Accoto, Dino; Dario, Paolo

    2005-11-22

    Motivated by the growing interest in ac electroosmosis as a reliable no moving parts strategy to control fluid motion in microfluidic devices for biomedical applications, such as lab-on-a-chip, we study transient and steady-state electrokinetic phenomena (electroosmosis and streaming currents) in infinitely extended rectangular charged microchannels. With the aid of Fourier series and Laplace transforms we provide a general formal solution of the problem, which is used to study the time-dependent response to sudden ac applied voltage differences in case of finite electric double layer. The Debye-Huckel approximation has been adopted to allow for an algebraic solution of the Poisson-Boltzmann problem in Fourier space. We obtain the expressions of flow velocity profiles, flow rates, streaming currents, as well as expressions of the complex hydraulic and electrokinetic conductances. We analyze in detail the dependence of the electrokinetic conductance on the extension of linear dimensions relative to the Debye length, with an eye on finite electric double layer effects. PMID:16351310

  2. An Ac transposon system based on maize chromosome 4S for isolating long-distance-transposed Ac tags in the maize genome.

    PubMed

    Wang, Fei; Li, Zhaoying; Fan, Jun; Li, Pengfei; Hu, Wei; Wang, Gang; Xu, Zhengkai; Song, Rentao

    2010-12-01

    Transposon tagging is an important tool for gene isolation and functional studies. In maize, several transposon-tagging systems have been developed, mostly using Activator/Dissociation (Ac/Ds) and Mutator systems. Here, we establish another Ac-based transposon system with the donor Ac tightly linked with sugary1 (su1) on maize chromosome 4S. Newly transposed Ac (tr-Acs) were detected based on a negative dosage effect, and long-distance-transposed Ac events were identified and isolated from the donor Ac by a simple backcross scheme. In this study, we identified 208 independent long-distance-transposed Ac lines. Thirty-one flanking sequences of these tr-Acs were isolated and localized in the maize genome. As found in previous studies, the tr-Acs preferentially inserted into genic sequences. The distribution of tr-Acs is not random. In our study, the tr-Acs preferentially transposed into chromosomes 1, 2, 9 and 10. We discuss the preferential distribution of tr-Acs from Ac systems. Our system is complementary to two other Ac-based regional-mutagenesis systems in maize, and the combined use of these systems will achieve an even and high-density distribution of Ac elements throughout the maize genome for functional-genomics studies.

  3. Plasma characteristics of argon glow discharge produced by AC power supply operating at low frequencies

    SciTech Connect

    Kongpiboolkid, Watcharapon; Mongkolnavin, Rattachat

    2015-04-24

    Non-thermal properties of Argon glow discharge operating with various operating pressures were measured and presented in this work. The Argon plasma is produced by a parallel conducting electrodes coupling with a high voltage AC power supply. The power supply can generate high AC voltage at various frequencies. The frequencies for the operation are in the range of a few kHz. The system is capable of generating electric field between the two metal electrodes discharge system. The characteristics of plasma produced were measured by optical emission spectroscopy (OES) technique where electron temperature (T{sub e}) and electron number density (n{sub e}) can be determined by line intensity ratio method. The value of electron number density was then determined from the Saha-Eggert equation. Our results show that the electron number density of the discharge obtained is of the order of 10{sup −17} − 10{sup −18} m{sup −3} where the electron temperature is between 1.00−2.00 eV for various operating frequencies used which are in good agreement with similar results published earlier.

  4. Wind Power Plant Voltage Stability Evaluation: Preprint

    SciTech Connect

    Muljadi, E.; Zhang, Y. C.

    2014-09-01

    Voltage stability refers to the ability of a power system to maintain steady voltages at all buses in the system after being subjected to a disturbance from a given initial operating condition. Voltage stability depends on a power system's ability to maintain and/or restore equilibrium between load demand and supply. Instability that may result occurs in the form of a progressive fall or rise of voltages of some buses. Possible outcomes of voltage instability are the loss of load in an area or tripped transmission lines and other elements by their protective systems, which may lead to cascading outages. The loss of synchronism of some generators may result from these outages or from operating conditions that violate a synchronous generator's field current limit, or in the case of variable speed wind turbine generator, the current limits of power switches. This paper investigates the impact of wind power plants on power system voltage stability by using synchrophasor measurements.

  5. AC corrosion -- A new challenge to pipeline integrity

    SciTech Connect

    Gummow, R.A.; Wakelin, R.G.; Segall, S.M.

    1998-12-31

    Corrosion of steel by alternating current was investigated as far back as the early 1900`s. These early studies and others in the 1950--60`s indicated that AC corrosion of steel was only a fraction of an equivalent amount of direct current (i.e. less than 1% of a like amount of DC) and in addition was controlled to negligible levels when cathodic protection was applied to industry standards. In 1986 however, an investigation into a corrosion failure on a high pressure gas pipeline in Germany indicated that the sole cause of the failure was AC corrosion. This corrosion failure on an otherwise well protected pipeline resulted in the initiation of several laboratory and field studies which indicated, that above a certain minimum AC current density, normal levels of cathodic protection will not control AC corrosion to acceptable levels and that AC mitigation is often required to prevent serious corrosion. Several other AC corrosion sites were discovered at coating holidays during the follow-up investigations in Germany. A graph, relating AC voltage to holiday size at the minimum AC current density for corrosion, is presented to assist the pipeline operator in determining whether or not a pipeline is susceptible to AC corrosion activity.

  6. Local Voltage Support from Distributed Energy Resources to Prevent Air Conditioner Motor Stalling

    SciTech Connect

    Baone, Chaitanya A; Xu, Yan; Kueck, John D

    2010-01-01

    Microgrid voltage collapse often happens when there is a high percentage of low inertia air-conditioning (AC) motors in the power systems. The stalling of the AC motors results in Fault Induced Delayed Voltage Recovery (FIDVR). A hybrid load model including typical building loads, AC motor loads, and other induction motor loads is built to simulate the motoring stalling phenomena. Furthermore, distributed energy resources (DE) with local voltage support capability are utilized to boost the local bus voltage during a fault, and prevent the motor stalling. The simulation results are presented. The analysis of the simulation results show that local voltage support from multiple DEs can effectively and economically solve the microgrid voltage collapse problem.

  7. Dynamical Coulomb blockade of tunnel junctions driven by alternating voltages

    NASA Astrophysics Data System (ADS)

    Grabert, Hermann

    2015-12-01

    The theory of the dynamical Coulomb blockade is extended to tunneling elements driven by a time-dependent voltage. It is shown that, for standard setups where an external voltage is applied to a tunnel junction via an impedance, time-dependent driving entails an excitation of the modes of the electromagnetic environment by the applied voltage. Previous approaches for ac driven circuits need to be extended to account for the driven bath modes. A unitary transformation involving also the variables of the electromagnetic environment is introduced which allows us to split off the time dependence from the Hamiltonian in the absence of tunneling. This greatly simplifies perturbation-theoretical calculations based on treating the tunneling Hamiltonian as a perturbation. In particular, the average current flowing in the leads of the tunnel junction is studied. Explicit results are given for the case of an applied voltage with a constant dc part and a sinusoidal ac part. The connection with standard dynamical Coulomb blockade theory for constant applied voltage is established. It is shown that an alternating voltage source reveals significant additional effects caused by the electromagnetic environment. The hallmark of the dynamical Coulomb blockade in ac driven devices is a suppression of higher harmonics of the current by the electromagnetic environment. The theory presented basically applies to all tunneling devices driven by alternating voltages.

  8. Onboard power line conditioning system for an electric or hybrid vehicle

    DOEpatents

    Kajouke, Lateef A.; Perisic, Milun

    2016-06-14

    A power line quality conditioning system for a vehicle includes an onboard rechargeable direct current (DC) energy storage system and an onboard electrical system coupled to the energy storage system. The energy storage system provides DC energy to drive an electric traction motor of the vehicle. The electrical system operates in a charging mode such that alternating current (AC) energy from a power grid external to the vehicle is converted to DC energy to charge the DC energy storage system. The electrical system also operates in a vehicle-to-grid power conditioning mode such that DC energy from the DC energy storage system is converted to AC energy to condition an AC voltage of the power grid.

  9. Recent applications of AC electrokinetics in biomolecular analysis on microfluidic devices.

    PubMed

    Sasaki, Naoki

    2012-01-01

    AC electrokinetics is a generic term that refers to an induced motion of particles and fluids under nonuniform AC electric fields. The AC electric fields are formed by application of AC voltages to microelectrodes, which can be easily integrated into microfluidic devices by standard microfabrication techniques. Moreover, the magnitude of the motion is large enough to control the mass transfer on the devices. These advantages are attractive for biomolecular analysis on the microfluidic devices, in which the characteristics of small space and microfluidics have been mainly employed. In this review, I describe recent applications of AC electrokinetics in biomolecular analysis on microfluidic devices. The applications include fluid pumping and mixing by AC electrokinetic flow, and manipulation of biomolecules such as DNA and proteins by various AC electrokinetic techniques. Future prospects for highly functional biomolecular analysis on microfluidic devices with the aid of AC electrokinetics are also discussed.

  10. Microfabricated AC impedance sensor

    DOEpatents

    Krulevitch, Peter; Ackler, Harold D.; Becker, Frederick; Boser, Bernhard E.; Eldredge, Adam B.; Fuller, Christopher K.; Gascoyne, Peter R. C.; Hamilton, Julie K.; Swierkowski, Stefan P.; Wang, Xiao-Bo

    2002-01-01

    A microfabricated instrument for detecting and identifying cells and other particles based on alternating current (AC) impedance measurements. The microfabricated AC impedance sensor includes two critical elements: 1) a microfluidic chip, preferably of glass substrates, having at least one microchannel therein and with electrodes patterned on both substrates, and 2) electrical circuits that connect to the electrodes on the microfluidic chip and detect signals associated with particles traveling down the microchannels. These circuits enable multiple AC impedance measurements of individual particles at high throughput rates with sufficient resolution to identify different particle and cell types as appropriate for environmental detection and clinical diagnostic applications.

  11. System and method for determining stator winding resistance in an AC motor

    DOEpatents

    Lu, Bin; Habetler, Thomas G.; Zhang, Pinjia; Theisen, Peter J.

    2011-05-31

    A system and method for determining stator winding resistance in an AC motor is disclosed. The system includes a circuit having an input connectable to an AC source and an output connectable to an input terminal of an AC motor. The circuit includes at least one contactor and at least one switch to control current flow and terminal voltages in the AC motor. The system also includes a controller connected to the circuit and configured to modify a switching time of the at least one switch to create a DC component in an output of the system corresponding to an input to the AC motor and determine a stator winding resistance of the AC motor based on the injected DC component of the voltage and current.

  12. Variable transposition of eight maize activator (ac) elements located on the short arm of chromosome 1.

    PubMed

    Sheridan, William F

    2011-09-01

    Eight Activator (Ac) transposable elements mapped to the maize chromosome arm 1S were assessed for Ac transposition rates. For each of the Ac stocks, plants homozygous for the single Ac element and the Ds reporter r1-sc:m3 on chromosome 10 were crossed as females by a homozygous r1-sc:m3 tester color-converted W22 line. The resulting ears produced mostly coarsely spotted kernels and a low frequency of either near-colorless fine-spotted kernels or nonspotted kernels. The relative frequency of these two types of near-colorless kernels differed among the eight Ac stocks. The extent to which increased Ac dosage results in nonspotted kernels may be Ac-specific. Although all of the Ac elements are in near-isogenic inbred W22 lines, they varied to a large extent in their transposition frequency. These differences might possibly result from structural differences among the Ac elements. Because one pair of Ac elements derived from Ac33 on chromosome arm 5S differed about 13-fold in transposition frequency and a second pair of Ac elements derived from Ac12 on chromosome arm 1S differed about 3-fold in transposition frequency, this is not a likely explanation for all eight Ac elements. The data presented here support the notion that the differences in transposition frequency of the eight Ac elements may be a reflection of variability in Ac transcription or accessibility of the transposase to the Ac element, resulting from differences in the chromatin environments wherein the Ac elements are located. This is the first report of variability in transposition rates among different Ac donor lines.

  13. Variable-frequency inverter controls torque, speed, and braking in ac induction motors

    NASA Technical Reports Server (NTRS)

    Nola, F. J.

    1974-01-01

    Dc to ac inverter provides optimum frequency and voltage to ac induction motor, in response to different motor-load and speed requirements. Inverter varies slip frequency of motor in proportion to required torque. Inverter protects motor from high current surges, controls negative slip to apply braking, and returns energy stored in momentum of load to dc power source.

  14. High-power ac/dc variable load simulator

    NASA Technical Reports Server (NTRS)

    Joncas, K. P.; Birnbach, S.; Bruce, L. D.; Smith, L.

    1975-01-01

    Design of medium-power dynamic electrical load simulator has been extended to permit simulation of ac as well as dc loads and to provide for operation at higher power levels. Simulator is internally protected against reverse voltage, overvoltage, overcurrent, and overload conditions.

  15. Batteries: Widening voltage windows

    NASA Astrophysics Data System (ADS)

    Xu, Kang; Wang, Chunsheng

    2016-10-01

    The energy output of aqueous batteries is largely limited by the narrow voltage window of their electrolytes. Now, a hydrate melt consisting of lithium salts is shown to expand such voltage windows, leading to a high-energy aqueous battery.

  16. AC magnetohydrodynamic microfluidic switch

    SciTech Connect

    Lemoff, A V; Lee, A P

    2000-03-02

    A microfluidic switch has been demonstrated using an AC Magnetohydrodynamic (MHD) pumping mechanism in which the Lorentz force is used to pump an electrolytic solution. By integrating two AC MHD pumps into different arms of a Y-shaped fluidic circuit, flow can be switched between the two arms. This type of switch can be used to produce complex fluidic routing, which may have multiple applications in {micro}TAS.

  17. Automatic voltage imbalance detector

    DOEpatents

    Bobbett, Ronald E.; McCormick, J. Byron; Kerwin, William J.

    1984-01-01

    A device for indicating and preventing damage to voltage cells such as galvanic cells and fuel cells connected in series by detecting sequential voltages and comparing these voltages to adjacent voltage cells. The device is implemented by using operational amplifiers and switching circuitry is provided by transistors. The device can be utilized in battery powered electric vehicles to prevent galvanic cell damage and also in series connected fuel cells to prevent fuel cell damage.

  18. AC power generation from microbial fuel cells

    NASA Astrophysics Data System (ADS)

    Lobo, Fernanda Leite; Wang, Heming; Forrestal, Casey; Ren, Zhiyong Jason

    2015-11-01

    Microbial fuel cells (MFCs) directly convert biodegradable substrates to electricity and carry good potential for energy-positive wastewater treatment. However, the low and direct current (DC) output from MFC is not usable for general electronics except small sensors, yet commercial DC-AC converters or inverters used in solar systems cannot be directly applied to MFCs. This study presents a new DC-AC converter system for MFCs that can generate alternating voltage in any desired frequency. Results show that AC power can be easily achieved in three different frequencies tested (1, 10, 60 Hz), and no energy storage layer such as capacitors was needed. The DC-AC converter efficiency was higher than 95% when powered by either individual MFCs or simple MFC stacks. Total harmonic distortion (THD) was used to investigate the quality of the energy, and it showed that the energy could be directly usable for linear electronic loads. This study shows that through electrical conversion MFCs can be potentially used in household electronics for decentralized off-grid communities.

  19. Isolation of sequences flanking Ac insertion sites by Ac casting.

    PubMed

    Wang, Dafang; Peterson, Thomas

    2013-01-01

    Localizing Ac insertions is a fundamental task in studying Ac-induced mutation and chromosomal rearrangements involving Ac elements. Researchers may sometimes be faced with the situation in which the sequence flanking one side of an Ac/Ds element is known, but the other flank is unknown. Or, a researcher may have a small sequence surrounding the Ac/Ds insertion site and needs to obtain additional flanking genomic sequences. One way to rapidly clone unknown Ac/Ds flanking sequences is via a PCR-based method termed Ac casting. This approach utilizes the somatic transposition activity of Ac during plant development, and provides an efficient means for short-range genome walking. Here we describe the principle of Ac casting, and show how it can be applied to isolate Ac macrotransposon insertion sites.

  20. A low voltage CMOS low drop-out voltage regulator

    NASA Astrophysics Data System (ADS)

    Bakr, Salma Ali; Abbasi, Tanvir Ahmad; Abbasi, Mohammas Suhaib; Aldessouky, Mohamed Samir; Abbasi, Mohammad Usaid

    2009-05-01

    A low voltage implementation of a CMOS Low Drop-Out voltage regulator (LDO) is presented. The requirement of low voltage devices is crucial for portable devices that require extensive computations in a low power environment. The LDO is implemented in 90nm generic CMOS technology. It generates a fixed 0.8V from a 2.5V supply which on discharging goes to 1V. The buffer stage used is unity gain configured unbuffered OpAmp with rail-to-rail swing input stage. The simulation result shows that the implemented circuit provides load regulation of 0.004%/mA and line regulation of -11.09mV/V. The LDO provides full load transient response with a settling time of 5.2μs. Further, the dropout voltage is 200mV and the quiescent current through the pass transistor (Iload=0) is 20μA. The total power consumption of this LDO (excluding bandgap reference) is only 80μW.

  1. Voltage-clearance recommendations for printed boards

    SciTech Connect

    Jennings, C W; Cave, G; Evans, A; Harrington, D J; Kirchenbaum, J; Martz, R E; Mierendorf, R C; Smith, G A

    1980-01-01

    Present and future trends in printed board designs point to higher circuit densities with narrower lines and closer spacings. Some designers are now laying out boards with 0.13 mm lines and spacings. The reduction of nominal spacing between conductive elements has raised questions concerning the adequacy of present voltage-clearance recommendations. The present recommendations are considered too conservative in that they are weighted with large safety factors, especially for small clearances, and are frequently disregarded by many designers. Published voltage breakdown measurements made on printed boards with comb patterns with their enhanced conductor test lengths show breakdowns occurring at much higher voltages than those specified for the clearances in existing documents. A Task Group was set up to review published breakdown measurements and to make any additional measurements necessary to provide voltage-clearance recommendations. These recommendations are reported.

  2. AC plasma anemometer—characteristics and design

    NASA Astrophysics Data System (ADS)

    Marshall, Curtis; Matlis, Eric; Corke, Thomas; Gogineni, Sivaram

    2015-08-01

    The characteristics and design of a high-bandwidth flow sensor that uses an AC glow discharge (plasma) as the sensing element is presented. The plasma forms in the air gap between two protruding low profile electrodes attached to a probe body. The output from the anemometer is an amplitude modulated version of the AC voltage input that contains information about the mean and fluctuating velocity components. The anemometer circuitry includes resistance and capacitance elements that simulate a dielectric-barrier to maintain a diffuse plasma, and a constant-current feedback control that maintains operation within the desired glow discharge regime over an extended range of air velocities. Mean velocity calibrations are demonstrated over a range from 0 to 140 m s-1. Over this velocity range, the mean output voltage varied linearly with air velocity, providing a constant static sensitivity. The effect of the electrode gap and input AC carrier frequency on the anemometer static sensitivity and dynamic response are investigated. Experiments are performed to compare measurements obtained with a plasma sensor operating at two AC carrier frequencies against that of a constant-temperature hot-wire. All three sensors were calibrated against the same known velocity reference. An uncertainty based on the standard deviation of the velocity calibration fit was applied to the mean and fluctuating velocity measurements of the three sensors. The motivation is not to replace hot-wires as a general measurement tool, but rather as an alternative to hot-wires in harsh environments or at high Mach numbers where they either have difficulty in surviving or lack the necessary frequency response.

  3. High Voltage SPT Performance

    NASA Technical Reports Server (NTRS)

    Manzella, David; Jacobson, David; Jankovsky, Robert

    2001-01-01

    A 2.3 kW stationary plasma thruster designed to operate at high voltage was tested at discharge voltages between 300 and 1250 V. Discharge specific impulses between 1600 and 3700 sec were demonstrated with thrust between 40 and 145 mN. Test data indicated that discharge voltage can be optimized for maximum discharge efficiency. The optimum discharge voltage was between 500 and 700 V for the various anode mass flow rates considered. The effect of operating voltage on optimal magnet field strength was investigated. The effect of cathode flow rate on thruster efficiency was considered for an 800 V discharge.

  4. HIGH VOLTAGE, HIGH CURRENT SPARK GAP SWITCH

    DOEpatents

    Dike, R.S.; Lier, D.W.; Schofield, A.E.; Tuck, J.L.

    1962-04-17

    A high voltage and current spark gap switch comprising two main electrodes insulatingly supported in opposed spaced relationship and a middle electrode supported medially between the main electrodes and symmetrically about the median line of the main electrodes is described. The middle electrode has a perforation aligned with the median line and an irradiation electrode insulatingly supported in the body of the middle electrode normal to the median line and protruding into the perforation. (AEC)

  5. High voltage spacecraft electrical systems design

    NASA Technical Reports Server (NTRS)

    Stone, R. E.

    1993-01-01

    Factors which must be considered when designing the best and the most cost-effective high-voltage electrical system for a spacecraft are discussed with particular attention given to the EMC considerations, high-voltage power bus, and harnesses. It is emphasized that the use of serial data buses and lines greatly simplify the harness design and weight. Careful attention to the grounding concept and the EMC requirements is necessary for insuring a 'quiet' spacecraft.

  6. Module Twelve: Series AC Resistive-Reactive Circuits; Basic Electricity and Electronics Individualized Learning System.

    ERIC Educational Resources Information Center

    Bureau of Naval Personnel, Washington, DC.

    The module covers series circuits which contain both resistive and reactive components and methods of solving these circuits for current, voltage, impedance, and phase angle. The module is divided into six lessons: voltage and impedance in AC (alternating current) series circuits, vector computations, rectangular and polar notation, variational…

  7. Tracking MOV operability under degraded voltage condition by periodic test measurements

    SciTech Connect

    Hussain, B.; Behera, A.K.; Alsammarae, A.J.

    1996-12-31

    The purpose of this paper is to develop a methodology for evaluating the operability of Alternating Current (AC) Motor Operated Valve (MOV) under degraded voltage condition, based on the seating parameter measured during surveillance/testing. This approach will help resolve Nuclear Regulatory Commission`s (NRC`s) concern on verifying the AC MOV`s design basis capability through periodic testing.

  8. Frequency Domain Analysis of Beat-Less Control Method for Converter-Inverter Driving Systems Applied to AC Electric Cars

    NASA Astrophysics Data System (ADS)

    Kimura, Akira

    In inverter-converter driving systems for AC electric cars, the DC input voltage of an inverter contains a ripple component with a frequency that is twice as high as the line voltage frequency, because of a single-phase converter. The ripple component of the inverter input voltage causes pulsations on torques and currents of driving motors. To decrease the pulsations, a beat-less control method, which modifies a slip frequency depending on the ripple component, is applied to the inverter control. In the present paper, the beat-less control method was analyzed in the frequency domain. In the first step of the analysis, transfer functions, which revealed the relationship among the ripple component of the inverter input voltage, the slip frequency, the motor torque pulsation and the current pulsation, were derived with a synchronous rotating model of induction motors. An analysis model of the beat-less control method was then constructed using the transfer functions. The optimal setting of the control method was obtained according to the analysis model. The transfer functions and the analysis model were verified through simulations.

  9. Line Replaceable Unit Analysis

    NASA Technical Reports Server (NTRS)

    Oepomo, T.; Prouty, T. V.

    1982-01-01

    Shuttle LRU (Line Replaceable Unit) Analysis Program (SLAP) aids in evaluation of LRU interface voltages in Shuttle orbiter electrical system. Slap includes reduced model of Shuttle LRU circuit. Although primarily intended for analysis of Shuttle LRU's SLAP could be adapted for voltage analysis in other situations.

  10. Strategies for Voltage Control and Transient Stability Assessment

    SciTech Connect

    Hiskens, Ian A.

    2013-09-25

    the impact of wind-power variability. It was also used to explore interactions between multiple wind-farms. Furthermore, these tools have been used to examine the impact of wind injection on transformer tap operation in subtransmission networks. The results of a tap operation simulation study show that voltage regulation at wind injection nodes increases tap change operations. The tradeo ff between local voltage regulation and tap change frequency is fundamentally important in optimizing the size of reactive compensation used for voltage regulation at wind injection nodes. Line congestion arising as a consequence of variable patterns of wind-power production has also been investigated. Two optimization problems have been formulated, based respectively on the DC and AC power flow models, for identifying vulnerable line segments. The DC optimization is computationally more e fficient, whereas the AC sensitivity-based optimization provides greater accuracy.

  11. Comparative study of 0° X-cut and Y + 36°-cut lithium niobate high-voltage sensing

    SciTech Connect

    Patel, N.; Branch, D. W.; Cular, S.; Schamiloglu, E.

    2015-08-15

    A comparison study between Y + 36° and 0° X-cut lithium niobate (LiNbO{sub 3}) was performed to evaluate the influence of crystal cut on the acoustic propagation to realize a piezoelectric high-voltage sensor. The acoustic time-of-flight for each crystal cut was measured when applying direct current (DC), alternating current (AC), and pulsed voltages. Results show that the voltage-induced shift in the acoustic wave propagation time scaled quadratically with voltage for DC and AC voltages applied to X-cut crystals. For the Y + 36° crystal, the voltage-induced shift scales linearly with DC voltages and quadratically with AC voltages. When applying 5 μs voltage pulses to both crystals, the voltage-induced shift scaled linearly with voltage. For the Y + 36° cut, the voltage-induced shift from applying DC voltages ranged from 10 to 54 ps and 35 to 778 ps for AC voltages at 640 V over the frequency range of 100 Hz–100 kHz. Using the same conditions as the Y + 36° cut, the 0° X-cut crystal sensed a shift of 10–273 ps for DC voltages and 189–813 ps for AC voltage application. For 5 μs voltage pulses, the 0° X-cut crystal sensed a voltage induced shift of 0.250–2 ns and the Y + 36°-cut crystal sensed a time shift of 0.115–1.6 ns. This suggests a frequency sensitive response to voltage where the influence of the crystal cut was not a significant contributor under DC, AC, or pulsed voltage conditions. The measured DC data were compared to a 1-D impedance matrix model where the predicted incremental length changed as a function of voltage. When the voltage source error was eliminated through physical modeling from the uncertainty budget, the combined uncertainty of the sensor (within a 95% confidence interval) decreased to 0.0033% using a Y + 36°-cut crystal and 0.0032% using an X-cut crystal for all the voltage conditions used in this experiment.

  12. Comparative study of 0° X-cut and Y+36°-cut lithium niobate high-voltage sensing

    SciTech Connect

    Patel, N.; Branch, D. W.; Schamiloglu, E.; Cular, S.

    2015-08-11

    A comparison study between Y+36° and 0° X-cut lithium niobate (LiNbO3) was performed to evaluate the influence of crystal cut on the acoustic propagation to realize a piezoelectric high-voltage sensor. The acoustic time-of-flight for each crystal cut was measured when applying direct current (DC), alternating current (AC), and pulsed voltages. Results show that the voltage-induced shift in the acoustic wave propagation time scaled quadratically with voltage for DC and AC voltages applied to X-cut crystals. For the Y+36° crystal, the voltage-induced shift scales linearly with DC voltages and quadratically with AC voltages. When applying 5 μs voltage pulses to both crystals, the voltage-induced shift scaled linearly with voltage. For the Y+36° cut, the voltage-induced shift from applying DC voltages ranged from 10 to 54 ps and 35 to 778 ps for AC voltages at 640 V over the frequency range of 100 Hz–100 kHz. Using the same conditions as the Y+36° cut, the 0° X-cut crystal sensed a shift of 10–273 ps for DC voltages and 189–813 ps for AC voltage application. For 5 μs voltage pulses, the 0° X-cut crystal sensed a voltage induced shift of 0.250–2 ns and the Y+36°-cut crystal sensed a time shift of 0.115–1.6 ns. This suggests a frequency sensitive response to voltage where the influence of the crystal cut was not a significant contributor under DC, AC, or pulsed voltage conditions. The measured DC data were compared to a 1-D impedance matrix model where the predicted incremental length changed as a function of voltage. Furthermore, when the voltage source error was eliminated through physical modeling from the uncertainty budget, the combined uncertainty of the sensor (within a 95% confidence interval) decreased to 0.0033% using a Y + 36°-cut crystal and 0.0032% using an X-cut crystal for all the voltage conditions used in this experiment.

  13. Comparative study of 0° X-cut and Y+36°-cut lithium niobate high-voltage sensing

    DOE PAGES

    Patel, N.; Branch, D. W.; Schamiloglu, E.; Cular, S.

    2015-08-11

    A comparison study between Y+36° and 0° X-cut lithium niobate (LiNbO3) was performed to evaluate the influence of crystal cut on the acoustic propagation to realize a piezoelectric high-voltage sensor. The acoustic time-of-flight for each crystal cut was measured when applying direct current (DC), alternating current (AC), and pulsed voltages. Results show that the voltage-induced shift in the acoustic wave propagation time scaled quadratically with voltage for DC and AC voltages applied to X-cut crystals. For the Y+36° crystal, the voltage-induced shift scales linearly with DC voltages and quadratically with AC voltages. When applying 5 μs voltage pulses to bothmore » crystals, the voltage-induced shift scaled linearly with voltage. For the Y+36° cut, the voltage-induced shift from applying DC voltages ranged from 10 to 54 ps and 35 to 778 ps for AC voltages at 640 V over the frequency range of 100 Hz–100 kHz. Using the same conditions as the Y+36° cut, the 0° X-cut crystal sensed a shift of 10–273 ps for DC voltages and 189–813 ps for AC voltage application. For 5 μs voltage pulses, the 0° X-cut crystal sensed a voltage induced shift of 0.250–2 ns and the Y+36°-cut crystal sensed a time shift of 0.115–1.6 ns. This suggests a frequency sensitive response to voltage where the influence of the crystal cut was not a significant contributor under DC, AC, or pulsed voltage conditions. The measured DC data were compared to a 1-D impedance matrix model where the predicted incremental length changed as a function of voltage. Furthermore, when the voltage source error was eliminated through physical modeling from the uncertainty budget, the combined uncertainty of the sensor (within a 95% confidence interval) decreased to 0.0033% using a Y + 36°-cut crystal and 0.0032% using an X-cut crystal for all the voltage conditions used in this experiment.« less

  14. Tevatron AC dipole system

    SciTech Connect

    Miyamoto, R.; Kopp, S.E.; Jansson, A.; Syphers, M.J.; /Fermilab

    2007-06-01

    The AC dipole is an oscillating dipole magnet which can induce large amplitude oscillations without the emittance growth and decoherence. These properties make it a good tool to measure optics of a hadron synchrotron. The vertical AC dipole for the Tevatron is powered by an inexpensive high power audio amplifier since its operating frequency is approximately 20 kHz. The magnet is incorporated into a parallel resonant system to maximize the current. The use of a vertical pinger magnet which has been installed in the Tevatron made the cost relatively inexpensive. Recently, the initial system was upgraded with a more powerful amplifier and oscillation amplitudes up to 2-3{sigma} were achieved with the 980 GeV proton beam. This paper discusses details of the Tevatron AC dipole system and also shows its test results.

  15. AC-3 audio coder

    NASA Astrophysics Data System (ADS)

    Todd, Craig

    1995-12-01

    AC-3 is a system for coding up to 5.1 channels of audio into a low bit-rate data stream. High quality may be obtained with compression ratios approaching 12-1 for multichannel audio programs. The high compression ratio is achieved by methods which do not increase decoder memory, and thus cost. The methods employed include: the transmission of a high frequency resolution spectral envelope; and a novel forward/backward adaptive bit allocation algorithm. In order to satisfy practical requirements of an emissions coder, the AC-3 syntax includes a number of features useful to broadcasters and consumers. These features include: loudness uniformity between programs; dynamic range control; and broadcaster control of downmix coefficients. The AC-3 coder has been formally selected for inclusion of the U.S. HDTV broadcast standard, and has been informally selected for several additional applications.

  16. Optical voltage reference

    DOEpatents

    Rankin, R.; Kotter, D.

    1994-04-26

    An optical voltage reference for providing an alternative to a battery source is described. The optical reference apparatus provides a temperature stable, high precision, isolated voltage reference through the use of optical isolation techniques to eliminate current and impedance coupling errors. Pulse rate frequency modulation is employed to eliminate errors in the optical transmission link while phase-lock feedback is employed to stabilize the frequency to voltage transfer function. 2 figures.

  17. AC/RF Superconductivity

    SciTech Connect

    Ciovati, Gianluigi

    2015-02-01

    This contribution provides a brief introduction to AC/RF superconductivity, with an emphasis on application to accelerators. The topics covered include the surface impedance of normal conductors and superconductors, the residual resistance, the field dependence of the surface resistance, and the superheating field.

  18. Power conditioning for low-voltage piezoelectric stack energy harvesters

    NASA Astrophysics Data System (ADS)

    Skow, E.; Leadenham, S.; Cunefare, K. A.; Erturk, A.

    2016-04-01

    Low-power vibration and acoustic energy harvesting scenarios typically require a storage component to be charged to enable wireless sensor networks, which necessitates power conditioning of the AC output. Piezoelectric beam-type bending mode energy harvesters or other devices that operate using a piezoelectric element at resonance produce high voltage levels, for which AC-DC converters and step-down DC-DC converters have been previously investigated. However, for piezoelectric stack energy harvesters operating off-resonance and producing low voltage outputs, a step-up circuit is required for power conditioning, such as seen in electromagnetic vibration energy scavengers, RF communications, and MEMS harvesters. This paper theoretically and experimentally investigates power conditioning of a low-voltage piezoelectric stack energy harvester.

  19. ac electroosmotic pumping induced by noncontact external electrodes.

    PubMed

    Wang, Shau-Chun; Chen, Hsiao-Ping; Chang, Hsueh-Chia

    2007-01-01

    Electroosmotic (EO) pumps based on dc electroosmosis is plagued by bubble generation and other electrochemical reactions at the electrodes at voltages beyond 1 V for electrolytes. These disadvantages limit their throughput and offset their portability advantage over mechanical syringe or pneumatic pumps. ac electroosmotic pumps at high frequency (>100 kHz) circumvent the bubble problem by inducing polarization and slip velocity on embedded electrodes,1 but they require complex electrode designs to produce a net flow. We report a new high-throughput ac EO pump design based on induced-polarization on the entire channel surface instead of just on the electrodes. Like dc EO pumps, our pump electrodes are outside of the load section and form a cm-long pump unit consisting of three circular reservoirs (3 mm in diameter) connected by a 1x1 mm channel. The field-induced polarization can produce an effective Zeta potential exceeding 1 V and an ac slip velocity estimated as 1 mmsec or higher, both one order of magnitude higher than earlier dc and ac pumps, giving rise to a maximum throughput of 1 mulsec. Polarization over the entire channel surface, quadratic scaling with respect to the field and high voltage at high frequency without electrode bubble generation are the reasons why the current pump is superior to earlier dc and ac EO pumps. PMID:19693362

  20. Background information on high voltage fields.

    PubMed

    Janes, D E

    1977-10-01

    The increased demand for power has led to higher voltages for overhead transmission lines. Environmentalists, governmental agencies, and some members of the scientific community have questioned if past biological effects research and experience with lower voltage lines provide adequate bases for predicting the possible health and environmental effects of the higher voltage lines. Only a small amount of work has been done to explore the possible effects, especially long term effects, of the exposure of biological systems to electric fields from transmission lines. Research in Western Europe and the United States has not identified any prompt or acute effects other than spark and electric discharge and no permanent effects. Contrasted with this are the studies of workers in Soviet and Spanish high voltage switchyards that report effects, such as excitability, headaches, drowsiness, fatique, and nausea, that are not found in Soviet line maintenance workers. The results of current and planned research, supported by both U.S. Government agencies and the private sector, should resolve a number of the present uncertanties and provide answers for the many questions concerning potential effects.

  1. Background information on high voltage fields.

    PubMed Central

    Janes, D E

    1977-01-01

    The increased demand for power has led to higher voltages for overhead transmission lines. Environmentalists, governmental agencies, and some members of the scientific community have questioned if past biological effects research and experience with lower voltage lines provide adequate bases for predicting the possible health and environmental effects of the higher voltage lines. Only a small amount of work has been done to explore the possible effects, especially long term effects, of the exposure of biological systems to electric fields from transmission lines. Research in Western Europe and the United States has not identified any prompt or acute effects other than spark and electric discharge and no permanent effects. Contrasted with this are the studies of workers in Soviet and Spanish high voltage switchyards that report effects, such as excitability, headaches, drowsiness, fatique, and nausea, that are not found in Soviet line maintenance workers. The results of current and planned research, supported by both U.S. Government agencies and the private sector, should resolve a number of the present uncertanties and provide answers for the many questions concerning potential effects. PMID:598346

  2. Understanding Voltage Decay in Lithium-Rich Manganese-Based Layered Cathode Materials by Limiting Cutoff Voltage.

    PubMed

    Yang, Jingsong; Xiao, Lifen; He, Wei; Fan, Jiangwei; Chen, Zhongxue; Ai, Xinping; Yang, Hanxi; Cao, Yuliang

    2016-07-27

    The effect of the cutoff voltages on the working voltage decay and cyclability of the lithium-rich manganese-based layered cathode (LRMO) was investigated by electrochemical measurements, electrochemical impedance spectroscopy, ex situ X-ray diffraction, transmission electron microscopy, and energy dispersive spectroscopy line scan technologies. It was found that both lower (2.0 V) and upper (4.8 V) cutoff voltages cause severe voltage decay with cycling due to formation of the spinel phase and migration of the transition metals inside the particles. Appropriate cutoff voltage between 2.8 and 4.4 V can effectively inhibit structural variation as the electrode demonstrates 92% capacity retention and indiscernible working voltage decay over 430 cycles. The results also show that phase transformation not only on high charge voltage but also on low discharge voltage should be addressed to obtain highly stable LRMO materials. PMID:27383918

  3. Magnetic fields and childhood cancer: an epidemiological investigation of the effects of high-voltage underground cables.

    PubMed

    Bunch, K J; Swanson, J; Vincent, T J; Murphy, M F G

    2015-09-01

    Epidemiological evidence of increased risks for childhood leukaemia from magnetic fields has implicated, as one source of such fields, high-voltage overhead lines. Magnetic fields are not the only factor that varies in their vicinity, complicating interpretation of any associations. Underground cables (UGCs), however, produce magnetic fields but have no other discernible effects in their vicinity. We report here the largest ever epidemiological study of high voltage UGCs, based on 52,525 cases occurring from 1962-2008, with matched birth controls. We calculated the distance of the mother's address at child's birth to the closest 275 or 400 kV ac or high-voltage dc UGC in England and Wales and the resulting magnetic fields. Few people are exposed to magnetic fields from UGCs limiting the statistical power. We found no indications of an association of risk with distance or of trend in risk with increasing magnetic field for leukaemia, and no convincing pattern of risks for any other cancer. Trend estimates for leukaemia as shown by the odds ratio (and 95% confidence interval) per unit increase in exposure were: reciprocal of distance 0.99 (0.95-1.03), magnetic field 1.01 (0.76-1.33). The absence of risk detected in relation to UGCs tends to add to the argument that any risks from overhead lines may not be caused by magnetic fields.

  4. Cytotoxicity of 213Bi- and 225Ac-immunoconjugates.

    PubMed

    Kaspersen, F M; Bos, E; Doornmalen, A V; Geerlings, M W; Apostolidis, C; Molinet, R

    1995-06-01

    This paper describes in vitro cytotoxicity experiments with 213Bi- and 225Ac-immunoconjugates on the human epidermoid tumour cell line A431 using a blood group A-reactive murine IgG (2D11) as the specific antibody and MOPC 21 as the control antibody. With both radionuclides, specific cell-killing was achieved. The observed cytotoxicity of 213Bi (T1/2 - 47 min) indicates that this radionuclide is a useful alternative for the alpha-emitter 212Bi in the treatment of blood-borne malignancies. 225Ac-immunoconjugates (T1/2 of 225Ac is 10 days) may be applicable for the treatment of solid tumours, since the daughter radionuclides of 225Ac contribute to the cytotoxic efficacy by a field effect (i.e. toxicity in an area distal from the antibody-binding site). The lack of an adequate chelator for 225Ac is a major drawback.

  5. Interplay between electron overheating and ac Josephson effect

    NASA Astrophysics Data System (ADS)

    De Cecco, A.; Le Calvez, K.; Sacépé, B.; Winkelmann, C. B.; Courtois, H.

    2016-05-01

    We study the response of high-critical-current proximity Josephson junctions to a microwave excitation. Electron overheating in such devices is known to create hysteretic dc voltage-current characteristics. Here we demonstrate that it also strongly influences the ac response. The interplay of electron overheating and ac Josephson dynamics is revealed by the evolution of the Shapiro steps with the microwave drive amplitude. Extending the resistively shunted Josephson junction model by including a thermal balance for the electronic bath coupled to phonons, a strong electron overheating is obtained.

  6. Electric voltage generation by antiferromagnetic dynamics

    NASA Astrophysics Data System (ADS)

    Yamane, Yuta; Ieda, Jun'ichi; Sinova, Jairo

    2016-05-01

    We theoretically demonstrate dc and ac electric voltage generation due to spin motive forces originating from domain wall motion and magnetic resonance, respectively, in two-sublattice antiferromagnets. Our theory accounts for the canting between the sublattice magnetizations, the nonadiabatic electron spin dynamics, and the Rashba spin-orbit coupling, with the intersublattice electron dynamics treated as a perturbation. This work suggests a way to observe and explore the dynamics of antiferromagnetic textures by electrical means, an important aspect in the emerging field of antiferromagnetic spintronics, where both manipulation and detection of antiferromagnets are needed.

  7. Voltage verification unit

    DOEpatents

    Martin, Edward J.

    2008-01-15

    A voltage verification unit and method for determining the absence of potentially dangerous potentials within a power supply enclosure without Mode 2 work is disclosed. With this device and method, a qualified worker, following a relatively simple protocol that involves a function test (hot, cold, hot) of the voltage verification unit before Lock Out/Tag Out and, and once the Lock Out/Tag Out is completed, testing or "trying" by simply reading a display on the voltage verification unit can be accomplished without exposure of the operator to the interior of the voltage supply enclosure. According to a preferred embodiment, the voltage verification unit includes test leads to allow diagnostics with other meters, without the necessity of accessing potentially dangerous bus bars or the like.

  8. Voltage tunable polymer laser device

    NASA Astrophysics Data System (ADS)

    Döring, Sebastian; Kollosche, Matthias; Rabe, Torsten; Kofod, Guggi; Stumpe, Joachim

    2012-03-01

    Since organic laser materials offer broad optical gain spectra they are predestined for the realization of widely tunable laser sources. Here we report on a compact organic laser device that allows for voltage controlled continuously wavelength tuning in the visible range of the spectrum by external deformation. The device consists of an elastomeric distributed feedback (DFB) laser and an electro-active elastomer actuator also known as artificial muscle. Second order DFB lasing is realized by a grating line structured elastomer substrate covered with a thin layer of dye doped polymer. To enable wavelength tuning the elastomer laser is placed at the center of the electro-active elastomer actuator. Chosen design of the actuator gives rise to homogeneous compression at this position. The voltage induced deformation of the artificial muscle is transferred to the elastomer laser and results in a decrease of grating period. This leads to an emission wavelength shift of the elastomer laser. The increase of actuation voltage to 3.25 kV decreased the emission wavelength from 604 nm to 557 nm, a change of 47 nm or 7.8%.

  9. Local Dynamic Reactive Power for Correction of System Voltage Problems

    SciTech Connect

    Kueck, John D; Rizy, D Tom; Li, Fangxing; Xu, Yan; Li, Huijuan; Adhikari, Sarina; Irminger, Philip

    2008-12-01

    Distribution systems are experiencing outages due to a phenomenon known as local voltage collapse. Local voltage collapse is occurring in part because modern air conditioner compressor motors are much more susceptible to stalling during a voltage dip than older motors. These motors can stall in less than 3 cycles (.05s) when a fault, such as on the sub-transmission system, causes voltage to sag to 70 to 60%. The reasons for this susceptibility are discussed in the report. During the local voltage collapse, voltages are depressed for a period of perhaps one or two minutes. There is a concern that these local events are interacting together over larger areas and may present a challenge to system reliability. An effective method of preventing local voltage collapse is the use of voltage regulation from Distributed Energy Resources (DER) that can supply or absorb reactive power. DER, when properly controlled, can provide a rapid correction to voltage dips and prevent motor stall. This report discusses the phenomenon and causes of local voltage collapse as well as the control methodology we have developed to counter voltage sag. The problem is growing because of the use of low inertia, high efficiency air conditioner (A/C) compressor motors and because the use of electric A/C is growing in use and becoming a larger percentage of system load. A method for local dynamic voltage regulation is discussed which uses reactive power injection or absorption from local DER. This method is independent, rapid, and will not interfere with conventional utility system voltage control. The results of simulations of this method are provided. The method has also been tested at the ORNL s Distributed Energy Communications and Control (DECC) Laboratory using our research inverter and synchronous condenser. These systems at the DECC Lab are interconnected to an actual distribution system, the ORNL distribution system, which is fed from TVA s 161kV sub-transmission backbone. The test results

  10. Control voltage and power fluctuations when connecting wind farms

    SciTech Connect

    Berinde, Ioan Bălan, Horia Oros, Teodora Susana

    2015-12-23

    Voltage, frequency, active power and reactive power are very important parameters in terms of power quality. These parameters are followed when connecting any power plant, the more the connection of wind farms. Connecting wind farms to the electricity system must not cause interference outside the limits set by regulations. Modern solutions for fast and automatic voltage control and power fluctuations using electronic control systems of reactive power flows. FACTS (Flexible Alternating Current Transmision System) systems, established on the basis of power electronic circuits ensure control of electrical status quantities to achieve the necessary transfer of power to the power grid. FACTS devices can quickly control parameters and sizes of state power lines, such as impedance line voltages and phase angles of the voltages of the two ends of the line. Their use can lead to improvement in power system operation by increasing the transmission capacity of power lines, power flow control lines, improved static and transient stability reserve.

  11. AC power systems handbook

    SciTech Connect

    Whitaker, J.

    1991-01-01

    Transient disturbances are what headaches are made of. Whatever you call them-spikes, surges, are power bumps-they can take your equipment down and leave you with a complicated and expensive repair job. Protection against transient disturbances is a science that demands attention to detail. This book explains how the power distribution system works, what can go wrong with it, and how to protect a facility against abnormalities. system grounding and shielding are covered in detail. Each major method of transient protection is analyzed and its relative merits discussed. The book provides a complete look at the critical elements of the ac power system. Provides a complete look at the ac power system from generation to consumption. Discusses the mechanisms that produce transient disturbances and how to protect against them. Presents diagrams to facilitate system design. Covers new areas, such as the extent of the transient disturbance problem, transient protection options, and stand-by power systems.

  12. Ultrafast high-pressure AC electro-osmotic pumps for portable biomedical microfluidics.

    PubMed

    Huang, Chien-Chih; Bazant, Martin Z; Thorsen, Todd

    2010-01-01

    This paper details the development of an integrated AC electro-osmotic (ACEO) microfluidic pump for dilute electrolytes consisting of a long serpentine microchannel lined with three dimensional (3D) stepped electrode arrays. Using low AC voltage (1 V rms, 1 kHz), power (5 mW) and current (4.5 mA) in water, the pump is capable of generating a 1.3 kPa head pressure, a 100-fold increase over prior ACEO pumps, and a 1.3 mm/s effective slip velocity over the electrodes without flow reversal. The integrated ACEO pump can utilize low ionic strength solutions such as distilled water as the working solution to pump physiological strength (100 mM) biological solutions in separate microfluidic devices, with potential applications in portable or implantable biomedical microfluidic devices. As a proof-of-concept experiment, the use of the ACEO pumps for DNA hybridization in a microfluidic microarray is demonstrated. PMID:20024054

  13. Microfluidic flow-focusing in ac electric fields.

    PubMed

    Tan, Say Hwa; Semin, Benoît; Baret, Jean-Christophe

    2014-03-21

    We demonstrate the control of droplet sizes by an ac voltage applied across microelectrodes patterned around a flow-focusing junction. The electrodes do not come in contact with the fluids to avoid electrochemical effects. We found several regimes of droplet production in electric fields, controlled by the connection of the chip, the conductivity of the dispersed phase and the frequency of the applied field. A simple electrical modelling of the chip reveals that the effective voltage at the tip of the liquid to be dispersed controls the production mechanism. At low voltages (≲ 600 V), droplets are produced in dripping regime; the droplet size is a function of the ac electric field. The introduction of an effective capillary number that takes into account the Maxwell stress can explain the dependance of droplet size with the applied voltage. At higher voltages (≳ 600 V), jets are observed. The stability of droplet production is a function of the fluid conductivity and applied field frequency reported in a set of flow diagrams. PMID:24401868

  14. Measurement of coupling resonance driving terms with the AC dipole

    SciTech Connect

    Miyamoto, R.

    2010-10-01

    Resonance driving terms for linear coupled betatron motion in a synchrotron ring can be determined from corresponding spectral lines of an excited coherent beam motion. An AC dipole is one of instruments to excite such a motion. When a coherent motion is excited with an AC dipole, measured Courant-Snyder parameters and betatron phase advance have apparent modulations, as if there is an additional quadrupole field at the location of the AC dipole. Hence, measurements of these parameters using the AC dipole require a proper interpretation of observed quantities. The situation is similar in measurements of resonance driving terms using the AC dipole. In this note, we derive an expression of coupled betatron motion excited with two AC dipoles in presence of skew quadrupole fields, discuss an impact of this quadrupole like effect of the AC dipole on a measurement of coupling resonance driving terms, and present an analytical method to determine the coupling resonance driving terms from quantities observed using the AC dipole.

  15. Low voltage to high voltage level shifter and related methods

    NASA Technical Reports Server (NTRS)

    Mentze, Erik J. (Inventor); Hess, Herbert L. (Inventor); Buck, Kevin M. (Inventor); Cox, David F. (Inventor)

    2006-01-01

    A shifter circuit comprises a high and low voltage buffer stages and an output buffer stage. The high voltage buffer stage comprises multiple transistors arranged in a transistor stack having a plurality of intermediate nodes connecting individual transistors along the stack. The transistor stack is connected between a voltage level being shifted to and an input voltage. An inverter of this stage comprises multiple inputs and an output. Inverter inputs are connected to a respective intermediate node of the transistor stack. The low voltage buffer stage has an input connected to the input voltage and an output, and is operably connected to the high voltage buffer stage. The low voltage buffer stage is connected between a voltage level being shifted away from and a lower voltage. The output buffer stage is driven by the outputs of the high voltage buffer stage inverter and the low voltage buffer stage.

  16. Equivalent Electrical Circuit Representations of AC Quantized Hall Resistance Standards

    PubMed Central

    Cage, M. E.; Jeffery, A.; Matthews, J.

    1999-01-01

    We use equivalent electrical circuits to analyze the effects of large parasitic impedances existing in all sample probes on four-terminal-pair measurements of the ac quantized Hall resistance RH. The circuit components include the externally measurable parasitic capacitances, inductances, lead resistances, and leakage resistances of ac quantized Hall resistance standards, as well as components that represent the electrical characteristics of the quantum Hall effect device (QHE). Two kinds of electrical circuit connections to the QHE are described and considered: single-series “offset” and quadruple-series. (We eliminated other connections in earlier analyses because they did not provide the desired accuracy with all sample probe leads attached at the device.) Exact, but complicated, algebraic equations are derived for the currents and measured quantized Hall voltages for these two circuits. Only the quadruple-series connection circuit meets our desired goal of measuring RH for both ac and dc currents with a one-standard-deviation uncertainty of 10−8 RH or less during the same cool-down with all leads attached at the device. The single-series “offset” connection circuit meets our other desired goal of also measuring the longitudinal resistance Rx for both ac and dc currents during that same cool-down. We will use these predictions to apply small measurable corrections, and uncertainties of the corrections, to ac measurements of RH in order to realize an intrinsic ac quantized Hall resistance standard of 10−8 RH uncertainty or less.

  17. Transmission Line Security Monitor

    SciTech Connect

    2011-01-01

    The Transmission Line Security Monitor is a multi-sensor monitor that mounts directly on high-voltage transmission lines to detect, characterize and communicate terrorist activity, human tampering and threatening conditions around support towers. For more information about INL's critical infrastructure protection research, visit http://www.facebook.com/idahonationallaboratory.

  18. Transmission Line Security Monitor

    ScienceCinema

    None

    2016-07-12

    The Transmission Line Security Monitor is a multi-sensor monitor that mounts directly on high-voltage transmission lines to detect, characterize and communicate terrorist activity, human tampering and threatening conditions around support towers. For more information about INL's critical infrastructure protection research, visit http://www.facebook.com/idahonationallaboratory.

  19. Three-phase ac-to-ac series-resonant power converter with a reduced number of thyristors

    SciTech Connect

    Klaassens, J.B.; de Beer, F. )

    1991-07-01

    This paper reports that ac-ac series-resonant converters have been proven to be functional and useful. Power pulse modulation with internal frequencies of tens of kHz and suited for multikilowatt power levels is applied to a series-resonant converter system for generating synthesized multiphase bipolar waveforms with reversible power flow and flow distortion. The use of a series-resonant circuit for power transfer and control obtains natural current commutation of the thyristors and the prevention of excessive stresses on components. Switches are required which have bidirectional current conduction and voltage blocking ability. The conventional series-resonant ac-ac converter applies a total for 24 anti-parallel thyristors. An alternative circuit configuration for the series-resonant ac-ac converter with only 12 thyristors is also presented. The alternative power circuit has three neutrals, related to the polyphase source, the load and the converter, which may be interconnected. If they are connected, the high-frequency component of the source and load currents will flow through the connection between the neutrals. The test results of a converter system generating three-phase sinusoidal input and output waveforms have demonstrated the significant aspects of this type of power interfaces.

  20. A New Regulation for Rural Power Grid Low-Voltage Controlling

    NASA Astrophysics Data System (ADS)

    Xian, L.; Wu, L. Z.; Yu, G. K.; Zhou, H.

    To solve the low voltage problem of rural power grid, this paper proposed a new mode of regulating voltage through substation, line and distribute substation. Through establish the mathematics module to analysis the three joint voltage regulation, and the control strategy of three joint regulation is also given in this paper. Through three joint voltage and reactive power compensation regulation, the voltage quality would be improved and the network loss would be reduced.

  1. High voltage power supply

    NASA Technical Reports Server (NTRS)

    Ruitberg, A. P.; Young, K. M. (Inventor)

    1985-01-01

    A high voltage power supply is formed by three discrete circuits energized by a battery to provide a plurality of concurrent output signals floating at a high output voltage on the order of several tens of kilovolts. In the first two circuits, the regulator stages are pulse width modulated and include adjustable ressistances for varying the duty cycles of pulse trains provided to corresponding oscillator stages while the third regulator stage includes an adjustable resistance for varying the amplitude of a steady signal provided to a third oscillator stage. In the first circuit, the oscillator, formed by a constant current drive network and a tuned resonant network included a step up transformer, is coupled to a second step up transformer which, in turn, supplies an amplified sinusoidal signal to a parallel pair of complementary poled rectifying, voltage multiplier stages to generate the high output voltage.

  2. Imaging voltage in neurons

    PubMed Central

    Peterka, Darcy S.; Takahashi, Hiroto; Yuste, Rafael

    2011-01-01

    In the last decades, imaging membrane potential has become a fruitful approach to study neural circuits, especially in invertebrate preparations with large, resilient neurons. At the same time, particularly in mammalian preparations, voltage imaging methods suffer from poor signal to noise and secondary side effects, and they fall short of providing single-cell resolution when imaging of the activity of neuronal populations. As an introduction to these techniques, we briefly review different voltage imaging methods (including organic fluorophores, SHG chromophores, genetic indicators, hybrid, nanoparticles and intrinsic approaches), and illustrate some of their applications to neuronal biophysics and mammalian circuit analysis. We discuss their mechanisms of voltage sensitivity, from reorientation, electrochromic or electro-optical phenomena, to interaction among chromophores or membrane scattering, and highlight their advantages and shortcomings, commenting on the outlook for development of novel voltage imaging methods. PMID:21220095

  3. High voltage DC power supply

    DOEpatents

    Droege, T.F.

    1989-12-19

    A high voltage DC power supply having a first series resistor at the output for limiting current in the event of a short-circuited output, a second series resistor for sensing the magnitude of output current, and a voltage divider circuit for providing a source of feedback voltage for use in voltage regulation is disclosed. The voltage divider circuit is coupled to the second series resistor so as to compensate the feedback voltage for a voltage drop across the first series resistor. The power supply also includes a pulse-width modulated control circuit, having dual clock signals, which is responsive to both the feedback voltage and a command voltage, and also includes voltage and current measuring circuits responsive to the feedback voltage and the voltage developed across the second series resistor respectively. 7 figs.

  4. High voltage DC power supply

    DOEpatents

    Droege, Thomas F.

    1989-01-01

    A high voltage DC power supply having a first series resistor at the output for limiting current in the event of a short-circuited output, a second series resistor for sensing the magnitude of output current, and a voltage divider circuit for providing a source of feedback voltage for use in voltage regulation is disclosed. The voltage divider circuit is coupled to the second series resistor so as to compensate the feedback voltage for a voltage drop across the first series resistor. The power supply also includes a pulse-width modulated control circuit, having dual clock signals, which is responsive to both the feedback voltage and a command voltage, and also includes voltage and current measuring circuits responsive to the feedback voltage and the voltage developed across the second series resistor respectively.

  5. A cascaded three-phase symmetrical multistage voltage multiplier

    NASA Astrophysics Data System (ADS)

    Iqbal, Shahid; Singh, G. K.; Besar, R.; Muhammad, G.

    2006-10-01

    A cascaded three-phase symmetrical multistage Cockcroft-Walton voltage multiplier (CW-VM) is proposed in this report. It consists of three single-phase symmetrical voltage multipliers, which are connected in series at their smoothing columns like string of batteries and are driven by three-phase ac power source. The smoothing column of each voltage multiplier is charged twice every cycle independently by respective oscillating columns and discharged in series through load. The charging discharging process completes six times a cycle and therefore the output voltage ripple's frequency is of sixth order of the drive signal frequency. Thus the proposed approach eliminates the first five harmonic components of load generated voltage ripples and sixth harmonic is the major ripple component. The proposed cascaded three-phase symmetrical voltage multiplier has less than half the voltage ripple, and three times larger output voltage and output power than the conventional single-phase symmetrical CW-VM. Experimental and simulation results of the laboratory prototype are given to show the feasibility of proposed cascaded three-phase symmetrical CW-VM.

  6. A calculable, transportable audio-frequency AC reference standard

    SciTech Connect

    Oldham, N.M.; Hetrick, P.S. ); Zeng, X. )

    1989-04-01

    A transportable ac voltage source is described, in which sinusoidal signals are synthesized digitally in the audio-frequency range. The rms value of the output waveform may be calculated by measuring the dc level of the individual steps used to generate the waveform. The uncertainty of this calculation at the 7-V level is typically less than +-5 ppm from 60 Hz to 2 kHz and less than +-10 ppm from 30 Hz to 15 kHz.

  7. Influence of Relative Humidity on AC Corona Discharge from Algae Attached on the Silicone Rubber

    NASA Astrophysics Data System (ADS)

    Sato, Daisuke; Hara, Yoshiaki; Kokufu, Morihide; Higashiyama, Yoshio

    To make clear the influence of algae growth at the surface of a polymer insulator in a practical transmission line, the characteristics of ac corona discharge from an aggregate algae particle were investigated. The aggregate algae particle was made of Protococcus viridis. Corona onset voltage from an aggregate algae particle was decreased as relative humidity increased. Under the condition of relatively higher relative humidity, luminous channel of corona discharge became more strongly and the number of corona pulses in the current waveform was increased. For an aggregate algae particle contaminated with sea salt including MgCl2, corona onset voltage decreased drastically at relative humidity above 40%. This property would result from deliquescence of MgCl2. Corona discharge was strongly affected by existence of MgCl2 in an aggregate algae particle. Surface resistance of algae attached to the surface of the silicone rubber sheet decreased in fourth figures for relative humidity from 20 to 90%. Therefore, the existence of algae on the polymer insulator inevitably affects the electric property and the surface property of the polymer insulator.

  8. 25 CFR 169.22 - Service lines.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER RIGHTS-OF-WAY OVER INDIAN LANDS § 169.22... power lines to a voltage of 14.5 kv. or less except lines to serve irrigation pumps and commercial and industrial uses which shall be limited to a voltage not to exceed 34.5 kv. A service line shall be for...

  9. [The Emission Spectroscopy of Nitrogen Discharge under Low Voltage at Room Temperature].

    PubMed

    Shen, Li-hua; Yu, Chun-xia; Yan, Bei; Zhang, Cheng-xiao

    2015-03-01

    A set of direct current (DC) discharge device of N2 plasma was developed, carbon nanotubes (CNT) modified ITO electrode was used as anode, aluminum plate as cathode, with -80 μm separation between them. Nitrogen emission spectra was observed at room temperature and low DC voltage (less than 150 V), and the emission spectrometry was used to diagnose the active species of the process of nitrogen discharge. Under DC discharge, the strongest energy band N2 (C3π(u)), the weak Gaydon's Green system N2 (H3 -Φ(u)-G3 Δ(g)) and the emission line of nitrogen atoms (4 p-4 p0) at 820 nm were observed. Found that metastable state of nitrogen molecules were the main factors leading to a series of excited state nitrogen atoms and nitrogen ionization. Compared the emission spectra under DC with that under alternating current (AC) (1.1 kV), and it can be seen that under DC the spectra band of nitrogen atoms can be obviously observed, and there was a molecular band in the range of 500 - 800 nm. The effect of oxygen and hydrogen on the emission spectra of nitrogen was investigated. The results showed that the oxygen inhibited the luminescence intensity of nitrogen, but the shape of spectra unchanged. All of the second positive system, Gaydon's Green system and atomic lines of nitrogen can be observed. The second positive system and Gaydon's Green system of nitrogen will be greatly affected when the volume ratio of nitrogen and hydrogen greatly affected is 1 : 1, which was due to the hydrogen. The hydrogen can depresse nitrogen plasma activation, and make the Gaydon's Green System disappeared. CNT modified ITO electrode can reduce the breakdown voltage, and the optical signal generated by the weakly ionized gas can be observed by the photo-multiplier tube at low voltage of 10 V. PMID:26117899

  10. Time varying voltage combustion control and diagnostics sensor

    DOEpatents

    Chorpening, Benjamin T.; Thornton, Jimmy D.; Huckaby, E. David; Fincham, William

    2011-04-19

    A time-varying voltage is applied to an electrode, or a pair of electrodes, of a sensor installed in a fuel nozzle disposed adjacent the combustion zone of a continuous combustion system, such as of the gas turbine engine type. The time-varying voltage induces a time-varying current in the flame which is measured and used to determine flame capacitance using AC electrical circuit analysis. Flame capacitance is used to accurately determine the position of the flame from the sensor and the fuel/air ratio. The fuel and/or air flow rate (s) is/are then adjusted to provide reduced flame instability problems such as flashback, combustion dynamics and lean blowout, as well as reduced emissions. The time-varying voltage may be an alternating voltage and the time-varying current may be an alternating current.

  11. Large Capacity SMES for Voltage Dip Compensation

    NASA Astrophysics Data System (ADS)

    Iwatani, Yu; Saito, Fusao; Ito, Toshinobu; Shimada, Mamoru; Ishida, Satoshi; Shimanuki, Yoshio

    Voltage dips of power grids due to thunderbolts, snow damage, and so on, cause serious damage to production lines of precision instruments, for example, semiconductors. In recent years, in order to solve this problem, uninterruptible power supply systems (UPS) are used. UPS, however, has small capacity, so a great number of UPS are needed in large factories. Therefore, we have manufactured the superconducting magnetic energy storage (SMES) system for voltage dip compensation able to protect loads with large capacity collectively. SMES has advantages such as space conservation, long lifetime and others. In field tests, cooperating with CHUBU Electric Power Co., Inc. we proved that SMES is valuable for compensating voltage dips. Since 2007, 10MVA SMES improved from field test machines has been running in a domestic liquid crystal display plant, and in 2008, it protected plant loads from a number of voltage dips. In this paper, we report the action principle and components of the improved SMES for voltage dip compensation, and examples of waveforms when 10MVA SMES compensated voltage dips.

  12. Power Electronic Transformer based Three-Phase PWM AC Drives

    NASA Astrophysics Data System (ADS)

    Basu, Kaushik

    A Transformer is used to provide galvanic isolation and to connect systems at different voltage levels. It is one of the largest and most expensive component in most of the high voltage and high power systems. Its size is inversely proportional to the operating frequency. The central idea behind a power electronic transformer (PET) also known as solid state transformer is to reduce the size of the transformer by increasing the frequency. Power electronic converters are used to change the frequency of operation. Steady reduction in the cost of the semiconductor switches and the advent of advanced magnetic materials with very low loss density and high saturation flux density implies economic viability and feasibility of a design with high power density. Application of PET is in generation of power from renewable energy sources, especially wind and solar. Other important application include grid tied inverters, UPS e.t.c. In this thesis non-resonant, single stage, bi-directional PET is considered. The main objective of this converter is to generate adjustable speed and magnitude pulse width modulated (PWM) ac waveforms from an ac or dc grid with a high frequency ac link. The windings of a high frequency transformer contains leakage inductance. Any switching transition of the power electronic converter connecting the inductive load and the transformer requires commutation of leakage energy. Commutation by passive means results in power loss, decrease in the frequency of operation, distortion in the output voltage waveform, reduction in reliability and power density. In this work a source based partially loss-less commutation of leakage energy has been proposed. This technique also results in partial soft-switching. A series of converters with novel PWM strategies have been proposed to minimize the frequency of leakage inductance commutation. These PETs achieve most of the important features of modern PWM ac drives including 1) Input power factor correction, 2) Common

  13. Simulation of an ac electro-osmotic pump with step microelectrodes

    NASA Astrophysics Data System (ADS)

    Kim, Byoung Jae; Lee, Seung-Hyun; Rezazadeh, Soghra; Sung, Hyung Jin

    2011-05-01

    Pumps with step microelectrodes subjected to an ac voltage are known to have faster pumping rates than those with planar asymmetric microelectrodes. The driving force for pumping in these systems is ac electro-osmosis. This paper aims to understand the flow behaviors of pumps with step microelectrodes by using a realistic model applicable to high external voltages. This model takes the steric effect due to the finite sizes of ions into account and copes with the exponential sensitivity of the counterion concentration to voltage. The effects on the pumping flow rate of varying the pump parameters were investigated. The geometrical parameters were optimized, and the effects of varying the ac frequency and amplitude were examined. The electrical potential of the fluid and the electrical charge at the electrode surface were solved simultaneously, and the Stokes equation was used to describe the fluid flow.

  14. Non-oxidized porous silicon-based power AC switch peripheries

    PubMed Central

    2012-01-01

    We present in this paper a novel application of porous silicon (PS) for low-power alternating current (AC) switches such as triode alternating current devices (TRIACs) frequently used to control small appliances (fridge, vacuum cleaner, washing machine, coffee makers, etc.). More precisely, it seems possible to benefit from the PS electrical insulation properties to ensure the OFF state of the device. Based on the technological aspects of the most commonly used AC switch peripheries physically responsible of the TRIAC blocking performances (leakage current and breakdown voltage), we suggest to isolate upper and lower junctions through the addition of a PS layer anodically etched from existing AC switch diffusion profiles. Then, we comment the voltage capability of practical samples emanating from the proposed architecture. Thanks to the characterization results of simple Al-PS-Si(P) structures, the experimental observations are interpreted, thus opening new outlooks in the field of AC switch peripheries. PMID:23057856

  15. Changes in behavioral responses of Lygus lineolaris (Hemiptera: Miridae) from various applied signal voltages during EPG recordings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A 3rd-generation AC-DC electrical penetration graph (EPG) monitor was used to study feeding behaviors of pre-reproductive adult Lygus lineolaris (Hemiptera: Miridae) on pinhead (<3mm) cotton squares, applying different signal voltages at several input impedances. The AC-DC monitor allows a user to s...

  16. High voltage pulse generator

    DOEpatents

    Fasching, George E.

    1977-03-08

    An improved high-voltage pulse generator has been provided which is especially useful in ultrasonic testing of rock core samples. An N number of capacitors are charged in parallel to V volts and at the proper instance are coupled in series to produce a high-voltage pulse of N times V volts. Rapid switching of the capacitors from the paralleled charging configuration to the series discharging configuration is accomplished by using silicon-controlled rectifiers which are chain self-triggered following the initial triggering of a first one of the rectifiers connected between the first and second of the plurality of charging capacitors. A timing and triggering circuit is provided to properly synchronize triggering pulses to the first SCR at a time when the charging voltage is not being applied to the parallel-connected charging capacitors. Alternate circuits are provided for controlling the application of the charging voltage from a charging circuit to be applied to the parallel capacitors which provides a selection of at least two different intervals in which the charging voltage is turned "off" to allow the SCR's connecting the capacitors in series to turn "off" before recharging begins. The high-voltage pulse-generating circuit including the N capacitors and corresponding SCR's which connect the capacitors in series when triggered "on" further includes diodes and series-connected inductors between the parallel-connected charging capacitors which allow sufficiently fast charging of the capacitors for a high pulse repetition rate and yet allow considerable control of the decay time of the high-voltage pulses from the pulse-generating circuit.

  17. Device for monitoring cell voltage

    DOEpatents

    Doepke, Matthias; Eisermann, Henning

    2012-08-21

    A device for monitoring a rechargeable battery having a number of electrically connected cells includes at least one current interruption switch for interrupting current flowing through at least one associated cell and a plurality of monitoring units for detecting cell voltage. Each monitoring unit is associated with a single cell and includes a reference voltage unit for producing a defined reference threshold voltage and a voltage comparison unit for comparing the reference threshold voltage with a partial cell voltage of the associated cell. The reference voltage unit is electrically supplied from the cell voltage of the associated cell. The voltage comparison unit is coupled to the at least one current interruption switch for interrupting the current of at least the current flowing through the associated cell, with a defined minimum difference between the reference threshold voltage and the partial cell voltage.

  18. Pulse-Width Control in Ladder Structure Four-Phase Rectifier for AC-Electromotive

    NASA Astrophysics Data System (ADS)

    Ivanov, V. V.; Myatez, S. V.; Langeman, E. G.; Schurov, N. I.

    2016-04-01

    Based on these studies the ways of power factor of the single-phase rectifiers operating in a single-phase AC network improving are suggested. The ladder four-phase rectifier is offered as a technical mean using a pulse-width method of controlling the rectified voltage. The pulse-width control efficiency as a way of the power factor rectifier with a ladder structure for AC electromotive improving is evaluated.

  19. Identification of /sup 233/Ac

    SciTech Connect

    Chu, Y.Y.; Zhou, M.L.

    1983-09-01

    We report in this paper identification of the new isotope /sup 233/Ac. Uranium targets were irradiated with 28 GeV protons; after rapid retrieval of the target and separation of actinium from thorium, /sup 233/Ac was allowed to decay into the known /sup 233/Th daughter. Exhaustive chemical purification was employed to permit the identification of /sup 233/Th via its characteristic ..gamma.. radiations. The half-life derived for /sup 233/Ac from several experiments is 2.3 +- 0.3 min. The production cross section for /sup 233/Ac is 100 ..mu..b.

  20. Fuzzy efficiency optimization of AC induction motors

    NASA Technical Reports Server (NTRS)

    Jani, Yashvant; Sousa, Gilberto; Turner, Wayne; Spiegel, Ron; Chappell, Jeff

    1993-01-01

    This paper describes the early states of work to implement a fuzzy logic controller to optimize the efficiency of AC induction motor/adjustable speed drive (ASD) systems running at less than optimal speed and torque conditions. In this paper, the process by which the membership functions of the controller were tuned is discussed and a controller which operates on frequency as well as voltage is proposed. The membership functions for this dual-variable controller are sketched. Additional topics include an approach for fuzzy logic to motor current control which can be used with vector-controlled drives. Incorporation of a fuzzy controller as an application-specific integrated circuit (ASIC) microchip is planned.

  1. HVDC-AC system interaction from AC harmonics. Volume 1. Harmonic impedance calculations. Final report

    SciTech Connect

    Breuer, G D; Chow, J H; Lindh, C B; Miller, N W; Numrich, F H; Price, W W; Turner, A E; Whitney, R R

    1982-09-01

    Improved methods are needed to characterize ac system harmonic behavior for ac filter design for HVDC systems. The purpose of this General Electric Company RP1138 research is to evaluate the present filter design practice and to investigate methods for calculating system harmonic impedances. An overview of ac filter design for HVDC systems and a survey of literature related to filter design have been performed. Two methods for calculating system harmonic impedances have been investigated. In the measurement method, an instrumentation system for measuring system voltage and current has been assembled. Different schemes of using the measurements to calculate system harmonic impedances have been studied. In the analytical method, a procedure to include various operating conditions has been proposed. Computer programs for both methods have been prepared, and the results of the measurement and analytical methods analyzed. A conclusion of the project is that the measurement and analytical methods both provided reasonable results. There are correlations between the measured and analytical results for most harmonics, although there are discrepancies between the assumptions used in the two methods. A sensitivity approach has been proposed to further correlate the results. From the results of the analysis, it is recommended that both methods should be tested further. For the measurement method, more testing should be done to cover different system operating conditions. In the analytical method, more detailed models for representing system components should be studied. In addition, alternative statistical and sensitivity approaches should be attempted.

  2. ACS after SM4: New Life for an Old Workhorse

    NASA Astrophysics Data System (ADS)

    Golimowski, David; Anderson, Jay; Armstrong, Amber; Arslanian, Steve; Bedin, Luigi; Bohlin, Ralph; Boyce, Kevin; Chapman, George; Cheng, Edward; Chiaberge, Marco; Cox, Colin; Desiardins, Tyler; Dye, Darryl; Ellis, Tracy; Ferguson, Brian; Fruchter, Andrew; Grogin, Norman; Lim, Pey Lian; Loose, Markus; Lucas, Ray; Lupie, Olivia; Mack, Jennifer; Maybhate, Aparna; Mil, Kathleen; Mutchler, Max; Ricardo, Raphael; Scott, Barbara; Serrano, Beverly; Sirianni, Marco; Smith, Linda; Suchkov, Anatoly A.; Waczynski, Augustyn; Welty, Alan; Wheeler, Thomas; Wilson, Erin

    2010-07-01

    The ACS CCD Electronics Box Replacement (CEB-R) installed during SM4 features a Teledyne SIDECAR ASIC that permits optimization of the WFC via adjustment of CCD clock voltages, bias voltages, and pixel transmission timing. An on-orbit campaign to optimize the performance of the WFC was undertaken at the start of the SMOV period. Initial tests with pre-SM4 default voltages and timing patterns showed that WFC's performance matches or exceeds its pre-failure levels, notwithstanding the expected increases in dark current and hot pixels and the decline in charge-transfer efficiency due to prolonged exposure to HST's radiation environment. One WFC CCD exhibited anomalous behavior when operated with nondefault settings of its reset drain voltage. Consequently, the optimization campaign was truncated after two iterations, and ACS science operations commenced with the pre-SM4 default configuration. Several artifacts attributed to the CEB-R appear in post-SM4 WFC images: large-scale but stable bias gradients, low-level but temporally variable horizontal stripes, a signal-dependent bias shift, and amplifier crosstalk. STScI has developed algorithms for the correction or mitigation of these electronic artifacts as well as for the restoration of images affected by continuously degrading CTE. Standalone correction packages are now or will soon be publicly available. These packages will be incorporated into the calacs package of the OPUS data pipeline by September 2011.

  3. ACS after Servicing Mission 4: The WFC Optimization Campaign

    NASA Astrophysics Data System (ADS)

    Golimowski, David; Cheng, Ed; Loose, Markus; Sirianni, Marco; Lupie, Olivia; Smith, Linda; Arslanian, Steve; Boyce, Kevin; Chapman, George; Chiaberge, Marco; Desjardins, Tyler; Dye, Darryl; Grogin, Norman; Lim, Pey Lian; Lucas, Ray; Maybhate, Aparna; Mil, Kathleen; Mutchler, Max; Ricardo, Raphael; Scott, Barbara; Serrano, Beverly; Suchkov, Anatoly; Waczynski, Augustyn; Welty, Alan; Wheeler, Thomas; Wilson, Erin

    2011-07-01

    The ACS CCD Electronics Box Replacement (CEB-R) installed during SM4 features a Teledyne SIDECAR ASIC that permits optimization of the WFC via adjustment of CCD clock voltages, bias voltages, and pixel transmission timing. A built-in oscilloscope mode allows sensing of the analog signal from each output amplifier. An on-orbit campaign to optimize the performance of the WFC was undertaken at the start of the SMOV period. Initial tests with pre-SM4 default voltages and timing patterns showed that WFC's performance matches or exceeds its pre-failure levels, notwithstanding the expected increases in dark current and hot pixels and the decline in charge-transfer efficiency due to prolonged exposure to HST's radiation environment. The WFC2 CCD exhibited anomalous behavior when operated with nondefault settings of its amplifiers' reset-drain voltage (VOD). The CCD again displayed normal behavior when VOD was restored to its default setting. Consequently, the Optimization Campaign was truncated after two iterations, and ACS science operations commenced with the pre-SM4 default configuration.

  4. Inductive energy harvesting from variable frequency and amplitude aircraft power lines

    NASA Astrophysics Data System (ADS)

    Toh, T. T.; Wright, S. W.; Kiziroglou, M. E.; Mueller, J.; Sessinghaus, M.; Yeatman, E. M.; Mitcheson, P. D.

    2014-11-01

    This paper presents a non-contact method of harvesting energy from an aircraft power line that has an AC current of variable amplitude and a frequency range of 360-800 Hz. The current and frequency characteristics of the aircraft power line are dependent on the rotation speed of the electrical generators and will therefore change during a flight. The harvester consists of an inductive coil with a ferrite core, which is interfaced to a rectifier, step-down regulator and supercapacitor. A prototype system was constructed to demonstrate reliable output voltage regulation across a supercapacitor that will supply a peak power of 100 mW under duty cycled load conditions. The system could fully charge a 40 mF supercapacitor to 3.3 V in 78 s from a power line current of 1.5 Arms at 650 Hz.

  5. Voltage controlled current source

    DOEpatents

    Casne, Gregory M.

    1992-01-01

    A seven decade, voltage controlled current source is described for use in testing intermediate range nuclear instruments that covers the entire test current range of from 10 picoamperes to 100 microamperes. High accuracy is obtained throughout the entire seven decades of output current with circuitry that includes a coordinated switching scheme responsive to the input signal from a hybrid computer to control the input voltage to an antilog amplifier, and to selectively connect a resistance to the antilog amplifier output to provide a continuous output current source as a function of a preset range of input voltage. An operator controlled switch provides current adjustment for operation in either a real-time simulation test mode or a time response test mode.

  6. Electron launching voltage monitor

    DOEpatents

    Mendel, Clifford W.; Savage, Mark E.

    1992-01-01

    An electron launching voltage monitor measures MITL voltage using a relationship between anode electric field and electron current launched from a cathode-mounted perturbation. An electron launching probe extends through and is spaced from the edge of an opening in a first MITL conductor, one end of the launching probe being in the gap between the MITL conductor, the other end being adjacent a first side of the first conductor away from the second conductor. A housing surrounds the launching probe and electrically connects the first side of the first conductor to the other end of the launching probe. A detector detects the current passing through the housing to the launching probe, the detected current being representative of the voltage between the conductors.

  7. Electron launching voltage monitor

    DOEpatents

    Mendel, C.W.; Savage, M.E.

    1992-03-17

    An electron launching voltage monitor measures MITL voltage using a relationship between anode electric field and electron current launched from a cathode-mounted perturbation. An electron launching probe extends through and is spaced from the edge of an opening in a first MITL conductor, one end of the launching probe being in the gap between the MITL conductor, the other end being adjacent a first side of the first conductor away from the second conductor. A housing surrounds the launching probe and electrically connects the first side of the first conductor to the other end of the launching probe. A detector detects the current passing through the housing to the launching probe, the detected current being representative of the voltage between the conductors. 5 figs.

  8. Characterization and snubbing of a bidirectional MCT in a resonant ac link converter

    NASA Technical Reports Server (NTRS)

    Lee, Tony; Elbuluk, Malik E.; Zinger, Donald S.

    1993-01-01

    The MOS-Controlled Thyristor (MCT) is emerging as a powerful switch that combines the better characteristics of existing power devices. A study of switching stresses on an MCT switch under zero voltage resonant switching is presented. The MCT is used as a bidirectional switch in an ac/ac pulse density modulated inverter for induction motor drive. Current and voltage spikes are observed and analyzed with variations in the timing of the switching. Different snubber circuit configurations are under investigation to minimize the effect of these transients. The results will be extended to study and test the MCT switching in a medium power (5 hp) induction motor drive.

  9. Voltage Regulators for Photovoltaic Systems

    NASA Technical Reports Server (NTRS)

    Delombard, R.

    1986-01-01

    Two simple circuits developed to provide voltage regulation for highvoltage (i.e., is greater than 75 volts) and low-voltage (i.e., is less than 36 volts) photovoltaic/battery power systems. Use of these circuits results in voltage regulator small, low-cost, and reliable, with very low power dissipation. Simple oscillator circuit controls photovoltaic-array current to regulate system voltage and control battery charging. Circuit senses battery (and system) voltage and adjusts array current to keep battery voltage from exceeding maximum voltage.

  10. Engineering analysis of electrical effects for the COTP 500KV transmission line and EBMUD aqueduct corridor

    SciTech Connect

    Lewis, O.C.; Bell, G.K.; Ma, J.

    1995-12-31

    A study was conducted to determine AC electrical interference effects arising in the East Bay Municipal Utility District`s (EBMUD) Mokelumne Aqueducts due to their proximity to the Olinda-Tracy 500 kilovolt (kV) transmission line operated by the Western Area Power Administration (WESTERN). A six-wire gradient control wire mitigation system selected by EBMUD was modeled and evaluated. The study shows that the mitigation system performs satisfactorily under all conditions examined. During steady state conditions, touch voltages are maintained below 15 volts throughout the entire length of the three aqueducts. During fault conditions, touch voltages are maintained below 263 volts, the design limit calculated according to ANSI/IEEE Standard 80. The currents flowing through the isolator/surge protectors do not exceed the ratings of these devices, during steady state and fault conditions.

  11. New zero voltage switching DC converter with flying capacitors

    NASA Astrophysics Data System (ADS)

    Lin, Bor-Ren; Shiau, Tung-Yuan

    2016-04-01

    A new soft switching converter is presented for medium power applications. Two full-bridge converters are connected in series at high voltage side in order to limit the voltage stress of power switches at Vin/2. Therefore, power metal-oxide-semiconductor field-effect transistors (MOSFETs) with 600 V voltage rating can be adopted for 1200 V input voltage applications. In order to balance two input split capacitor voltages in every switching cycle, two flying capacitors are connected on the AC side of two full-bridge converters. Phase-shift pulse-width modulation (PS-PWM) is adopted to regulate the output voltage. Based on the resonant behaviour by the output capacitance of MOSFETs and the resonant inductance, active MOSFETs can be turned on under zero voltage switching (ZVS) during the transition interval. Thus, the switching losses of power MOSFETs are reduced. Two full-bridge converters are used in the proposed circuit to share load current and reduce the current stress of passive and active components. The circuit analysis and design example of the prototype circuit are provided in detail and the performance of the proposed converter is verified by the experiments.

  12. Microwave integrated circuit for Josephson voltage standards

    NASA Technical Reports Server (NTRS)

    Holdeman, L. B.; Toots, J.; Chang, C. C. (Inventor)

    1980-01-01

    A microwave integrated circuit comprised of one or more Josephson junctions and short sections of microstrip or stripline transmission line is fabricated from thin layers of superconducting metal on a dielectric substrate. The short sections of transmission are combined to form the elements of the circuit and particularly, two microwave resonators. The Josephson junctions are located between the resonators and the impedance of the Josephson junctions forms part of the circuitry that couples the two resonators. The microwave integrated circuit has an application in Josephson voltage standards. In this application, the device is asymmetrically driven at a selected frequency (approximately equal to the resonance frequency of the resonators), and a d.c. bias is applied to the junction. By observing the current voltage characteristic of the junction, a precise voltage, proportional to the frequency of the microwave drive signal, is obtained.

  13. AC Electroosmotic Pumping in Nanofluidic Funnels.

    PubMed

    Kneller, Andrew R; Haywood, Daniel G; Jacobson, Stephen C

    2016-06-21

    We report efficient pumping of fluids through nanofluidic funnels when a symmetric AC waveform is applied. The asymmetric geometry of the nanofluidic funnel induces not only ion current rectification but also electroosmotic flow rectification. In the base-to-tip direction, the funnel exhibits a lower ion conductance and a higher electroosmotic flow velocity, whereas, in the tip-to-base direction, the funnel has a higher ion conductance and a lower electroosmotic flow velocity. Consequently, symmetric AC waveforms easily pump fluid through the nanofunnels over a range of frequencies, e.g., 5 Hz to 5 kHz. In our experiments, the nanofunnels were milled into glass substrates with a focused ion beam (FIB) instrument, and the funnel design had a constant 5° taper with aspect ratios (funnel tip width to funnel depth) of 0.1 to 1.0. We tracked ion current rectification by current-voltage (I-V) response and electroosmotic flow rectification by transport of a zwitterionic fluorescent probe. Rectification of ion current and electroosmotic flow increased with increasing electric field applied to the nanofunnel. Our results support three-dimensional simulations of ion transport and electroosmotic transport through nanofunnels, which suggest the asymmetric electroosmotic transport stems from an induced pressure at the junction of the nanochannel and nanofunnel tip. PMID:27230495

  14. Cooling Floor AC Systems

    NASA Astrophysics Data System (ADS)

    Jun, Lu; Hao, Ding; Hong, Zhang; Ce, Gao Dian

    The present HVAC equipments for the residential buildings in the Hot-summer-and-Cold-winter climate region are still at a high energy consuming level. So that the high efficiency HVAC system is an urgently need for achieving the preset government energy saving goal. With its advantage of highly sanitary, highly comfortable and uniform of temperature field, the hot-water resource floor radiation heating system has been widely accepted. This paper has put forward a new way in air-conditioning, which combines the fresh-air supply unit and such floor radiation system for the dehumidification and cooling in summer or heating in winter. By analyze its advantages and limitations, we found that this so called Cooling/ Heating Floor AC System can improve the IAQ of residential building while keep high efficiency quality. We also recommend a methodology for the HVAC system designing, which will ensure the reduction of energy cost of users.

  15. Transport ac losses of a second-generation HTS tape with a ferromagnetic substrate and conducting stabilizer

    NASA Astrophysics Data System (ADS)

    Li, Shuo; Chen, Du-Xing; Fang, Jin

    2015-12-01

    The current-voltage curve and transport ac loss of a second-generation HTS tape with a ferromagnetic NiW substrate and brass stabilizer are measured. It is found that the ac loss is up to two orders of magnitude larger than what is expected by the power-law E(J) determined by the current-voltage curve and increases with increasing frequency. Modeling results show that the overly large ac loss is contributed by the ac loss in the HTS strip enhanced by the NiW substrate and the magnetic hysteresis loss in the substrate, and the frequency-dependent loss occurs in the brass layer covering the substrate but not in the ferromagnetic substrate itself as assumed previously. The ac loss in the brass layer is associated with transport currents but not eddy currents, and it has some features similar to ordinary eddy-current loss with significant differences.

  16. Simulation analysis of three-phase current type AC-to-DC converter with high power factor

    SciTech Connect

    Okui, Yoshiaki; Yamada, Hajime

    1997-03-01

    A new three-phase current type AC-to-DC converter has been developed by the authors. This paper describes the principle of the circuit operation and the circuit configuration of the AC-to-DC converter controlled by PWM. Simulation analysis of each waveform, such as AC and DC voltages and currents, are calculated by Euler`s method. The simulated values of the total power factor agreed with the measured values within the difference of 5.8% on the condition of full load, 10kW. When the AC side voltage is unbalanced, it is found by simulation that the total harmonic distortion controlled by both feedforward control and AC side current feedback control (proportion gain, k{sub 4} = 1) is restrained at only 38% compared with only feedforward control (k{sub 4} = 0).

  17. Marine High Voltage Power Conditioning and Transmission System with Integrated Storage DE-EE0003640 Final Report

    SciTech Connect

    Frank Hoffmann, PhD; Aspinall, Rik

    2012-12-10

    Design, Development, and test of the three-port power converter for marine hydrokinetic power transmission. Converter provides ports for AC/DC conversion of hydrokinetic power, battery storage, and a low voltage to high voltage DC port for HVDC transmission to shore. The report covers the design, development, implementation, and testing of a prototype built by PPS.

  18. Module Nine: Relationships of Current, Counter EMF, and Voltage in LR Circuits; Basic Electricity and Electronics Individualized Learning System.

    ERIC Educational Resources Information Center

    Bureau of Naval Personnel, Washington, DC.

    The student will study the ways that inductance affects voltage and current in Direct Current (DC) and Alternating Current (AC) circuits and why and how inductors cause these actions. The module is divided into six lessons: rise and decay of current and voltage, LR (inductive-resistive) time constant, using the universal TC (time constant) chart,…

  19. Droplet condensation on superhydrophobic surfaces with enhanced dewetting under a tangential AC electric field

    NASA Astrophysics Data System (ADS)

    Yan, Xinzhu; Li, Jian; Li, Licheng; Huang, Zhengyong; Wang, Feipeng; Wei, Yuan

    2016-10-01

    In this Letter, the dewetting behavior of superhydrophobic condensing surfaces under a tangential AC electric field is reported. The surface coverage of condensed droplets only exhibits a negligible increase with time. The jumping frequency of droplets is enhanced. The AC electric field motivates the dynamic transition of droplets from stretch to recoil, resulting in the counterforce propelling droplet jumping. The considerable horizontal component of jumping velocity facilitates droplet departure from superhydrophobic surfaces. Both the amplitude and frequency of AC voltage are important factors for droplet departure and dewetting effect. Thereby, the tangential electric field provides a unique and easily implementable approach to enhance droplet removal from superhydrophobic condensing surfaces.

  20. Voltage-Controlled Oscillator

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Integrated Component Systems, Inc. incorporated information from a NASA Tech Briefs article into a voltage-controlled oscillator it designed for a customer. The company then applied the technology to its series of phase-locked loop synthesizers, which offer superior phase noise performance.

  1. High Voltage Insulation Technology

    NASA Astrophysics Data System (ADS)

    Scherb, V.; Rogalla, K.; Gollor, M.

    2008-09-01

    In preparation of new Electronic Power Conditioners (EPC's) for Travelling Wave Tub Amplifiers (TWTA's) on telecom satellites a study for the development of new high voltage insulation technology is performed. The initiative is mandatory to allow compact designs and to enable higher operating voltages. In a first task a market analysis was performed, comparing different materials with respect to their properties and processes. A hierarchy of selection criteria was established and finally five material candidates (4 Epoxy resins and 1 Polyurethane resin) were selected to be further investigated in the test program. Samples for the test program were designed to represent core elements of an EPC, the high voltage transformer and Printed Circuit Boards of the high voltage section. All five materials were assessed in the practical work flow of the potting process and electrical, mechanical, thermal and lifetime testing was performed. Although the lifetime tests results were overlayed by a larges scatter, finally two candidates have been identified for use in a subsequent qualification program. This activity forms part of element 5 of the ESA ARTES Programme.

  2. Geomagnetism and Induced Voltage

    ERIC Educational Resources Information Center

    Abdul-Razzaq, W.; Biller, R. D.

    2010-01-01

    Introductory physics laboratories have seen an influx of "conceptual integrated science" over time in their classrooms with elements of other sciences such as chemistry, biology, Earth science, and astronomy. We describe a laboratory to introduce this development, as it attracts attention to the voltage induced in the human brain as it is…

  3. Measuring Breakdown Voltage.

    ERIC Educational Resources Information Center

    Auer, Herbert J.

    1978-01-01

    The article discusses an aspect of conductivity, one of the electrical properties subdivisions, and describes a tester that can be shop-built. Breakdown voltage of an insulation material is specifically examined. Test procedures, parts lists, diagrams, and test data form are included. (MF)

  4. Ac Josephson effect in hysteretic junctions: Range and stability of phase lock

    SciTech Connect

    Kautz, R.L.

    1981-05-01

    The rf-induced constant voltage steps generated by the ac Josephson effect are studied within the context of the Stewart-McCumber model. Simulations are used to determine the range of current bias over which phase lock occurs for model parameters appropriate to hysteretic tunnel junctions. The effect of noise on phase lock is also considered. The results are applied to a zero-bias voltage standard proposed by Levinsen et al.

  5. Distribution of Activator (Ac) Throughout the Maize Genome for Use in Regional Mutagenesis

    PubMed Central

    Kolkman, Judith M.; Conrad, Liza J.; Farmer, Phyllis R.; Hardeman, Kristine; Ahern, Kevin R.; Lewis, Paul E.; Sawers, Ruairidh J. H.; Lebejko, Sara; Chomet, Paul; Brutnell, Thomas P.

    2005-01-01

    A collection of Activator (Ac)-containing, near-isogenic W22 inbred lines has been generated for use in regional mutagenesis experiments. Each line is homozygous for a single, precisely positioned Ac element and the Ds reporter, r1-sc:m3. Through classical and molecular genetic techniques, 158 transposed Ac elements (tr-Acs) were distributed throughout the maize genome and 41 were precisely placed on the linkage map utilizing multiple recombinant inbred populations. Several PCR techniques were utilized to amplify DNA fragments flanking tr-Ac insertions up to 8 kb in length. Sequencing and database searches of flanking DNA revealed that the majority of insertions are in hypomethylated, low- or single-copy sequences, indicating an insertion site preference for genic sequences in the genome. However, a number of Ac transposition events were to highly repetitive sequences in the genome. We present evidence that suggests Ac expression is regulated by genomic context resulting in subtle variations in Ac-mediated excision patterns. These tr-Ac lines can be utilized to isolate genes with unknown function, to conduct fine-scale genetic mapping experiments, and to generate novel allelic diversity in applied breeding programs. PMID:15520264

  6. Excitation of voltage oscillations in an induction voltage adder

    NASA Astrophysics Data System (ADS)

    Bruner, Nichelle; Genoni, Thomas; Madrid, Elizabeth; Welch, Dale; Hahn, Kelly; Oliver, Bryan

    2009-07-01

    The induction voltage adder is an accelerator architecture used in recent designs of pulsed-power driven x-ray radiographic systems such as Sandia National Laboratories’ Radiographic Integrated Test Stand (RITS), the Atomic Weapons Establishment’s planned Hydrus Facility, and the Naval Research Laboratory’s Mercury. Each of these designs relies on magnetic insulation to prevent electron loss across the anode-cathode gap in the vicinity of the adder as well as in the coaxial transmission line. Particle-in-cell simulations of the RITS adder and transmission line show that, as magnetic insulation is being established during a pulse, some electron loss occurs across the gap. Sufficient delay in the cavity pulse timings provides an opportunity for high-momentum electrons to deeply penetrate the cavities of the adder cells where they can excite radio-frequency resonances. These oscillations may be amplified in subsequent gaps, resulting in oscillations in the output power. The specific modes supported by the RITS-6 accelerator and details of the mechanism by which they are excited are presented in this paper.

  7. 30 CFR 77.704-10 - Tying into energized high-voltage surface circuits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Tying into energized high-voltage surface... AREAS OF UNDERGROUND COAL MINES Grounding § 77.704-10 Tying into energized high-voltage surface circuits. If the work of forming an additional circuit by tying into an energized high-voltage surface line...

  8. 30 CFR 75.705-10 - Tying into energized high-voltage surface circuits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Tying into energized high-voltage surface....705-10 Tying into energized high-voltage surface circuits. If the work of forming an additional circuit by tying into an energized high-voltage surface line is performed from the ground, any...

  9. 30 CFR 75.705-10 - Tying into energized high-voltage surface circuits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Tying into energized high-voltage surface....705-10 Tying into energized high-voltage surface circuits. If the work of forming an additional circuit by tying into an energized high-voltage surface line is performed from the ground, any...

  10. 30 CFR 77.704-10 - Tying into energized high-voltage surface circuits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Tying into energized high-voltage surface... AREAS OF UNDERGROUND COAL MINES Grounding § 77.704-10 Tying into energized high-voltage surface circuits. If the work of forming an additional circuit by tying into an energized high-voltage surface line...

  11. 30 CFR 77.704-10 - Tying into energized high-voltage surface circuits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Tying into energized high-voltage surface... AREAS OF UNDERGROUND COAL MINES Grounding § 77.704-10 Tying into energized high-voltage surface circuits. If the work of forming an additional circuit by tying into an energized high-voltage surface line...

  12. 30 CFR 75.705-10 - Tying into energized high-voltage surface circuits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Tying into energized high-voltage surface....705-10 Tying into energized high-voltage surface circuits. If the work of forming an additional circuit by tying into an energized high-voltage surface line is performed from the ground, any...

  13. 30 CFR 75.705-10 - Tying into energized high-voltage surface circuits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Tying into energized high-voltage surface....705-10 Tying into energized high-voltage surface circuits. If the work of forming an additional circuit by tying into an energized high-voltage surface line is performed from the ground, any...

  14. 30 CFR 77.704-10 - Tying into energized high-voltage surface circuits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Tying into energized high-voltage surface... AREAS OF UNDERGROUND COAL MINES Grounding § 77.704-10 Tying into energized high-voltage surface circuits. If the work of forming an additional circuit by tying into an energized high-voltage surface line...

  15. Assessing Fungal Population in Soil Planted with Cry1Ac and CPTI Transgenic Cotton and Its Conventional Parental Line Using 18S and ITS rDNA Sequences over Four Seasons

    PubMed Central

    Qi, Xiemin; Liu, Biao; Song, Qinxin; Zou, Bingjie; Bu, Ying; Wu, Haiping; Ding, Li; Zhou, Guohua

    2016-01-01

    Long-term growth of genetically modified plants (GMPs) has raised concerns regarding their ecological effects. Here, FLX-pyrosequencing of region I (18S) and region II (ITS1, 5.8S, and ITS2) rDNA was used to characterize fungal communities in soil samples after 10-year monoculture of one representative transgenic cotton line (TC-10) and 15-year plantation of various transgenic cotton cultivars (TC-15mix) over four seasons. Soil fungal communities in the rhizosphere of non-transgenic control (CC) were also compared. No notable differences were observed in soil fertility variables among CC, TC-10, and TC-15mix. Within seasons, the different estimations were statistically indistinguishable. There were 411 and 2 067 fungal operational taxonomic units in the two regions, respectively. More than 75% of fungal taxa were stable in both CC and TC except for individual taxa with significantly different abundance between TC and CC. Statistical analysis revealed no significant differences between CC and TC-10, while discrimination of separating TC-15mix from CC and TC-10 with 37.86% explained variance in PCoA and a significant difference of Shannon indexes between TC-10 and TC-15mix were observed in region II. As TC-15mix planted with a mixture of transgenic cottons (Zhongmian-29, 30, and 33B) for over 5 years, different genetic modifications may introduce variations in fungal diversity. Further clarification is necessary by detecting the fungal dynamic changes in sites planted in monoculture of various transgenic cottons. Overall, we conclude that monoculture of one representative transgenic cotton cultivar may have no effect on fungal diversity compared with conventional cotton. Furthermore, the choice of amplified region and methodology has potential to affect the outcome of the comparison between GM-crop and its parental line. PMID:27462344

  16. Assessing Fungal Population in Soil Planted with Cry1Ac and CPTI Transgenic Cotton and Its Conventional Parental Line Using 18S and ITS rDNA Sequences over Four Seasons.

    PubMed

    Qi, Xiemin; Liu, Biao; Song, Qinxin; Zou, Bingjie; Bu, Ying; Wu, Haiping; Ding, Li; Zhou, Guohua

    2016-01-01

    Long-term growth of genetically modified plants (GMPs) has raised concerns regarding their ecological effects. Here, FLX-pyrosequencing of region I (18S) and region II (ITS1, 5.8S, and ITS2) rDNA was used to characterize fungal communities in soil samples after 10-year monoculture of one representative transgenic cotton line (TC-10) and 15-year plantation of various transgenic cotton cultivars (TC-15mix) over four seasons. Soil fungal communities in the rhizosphere of non-transgenic control (CC) were also compared. No notable differences were observed in soil fertility variables among CC, TC-10, and TC-15mix. Within seasons, the different estimations were statistically indistinguishable. There were 411 and 2 067 fungal operational taxonomic units in the two regions, respectively. More than 75% of fungal taxa were stable in both CC and TC except for individual taxa with significantly different abundance between TC and CC. Statistical analysis revealed no significant differences between CC and TC-10, while discrimination of separating TC-15mix from CC and TC-10 with 37.86% explained variance in PCoA and a significant difference of Shannon indexes between TC-10 and TC-15mix were observed in region II. As TC-15mix planted with a mixture of transgenic cottons (Zhongmian-29, 30, and 33B) for over 5 years, different genetic modifications may introduce variations in fungal diversity. Further clarification is necessary by detecting the fungal dynamic changes in sites planted in monoculture of various transgenic cottons. Overall, we conclude that monoculture of one representative transgenic cotton cultivar may have no effect on fungal diversity compared with conventional cotton. Furthermore, the choice of amplified region and methodology has potential to affect the outcome of the comparison between GM-crop and its parental line. PMID:27462344

  17. ACS CCD Stability Monitor

    NASA Astrophysics Data System (ADS)

    Grogin, Norman

    2012-10-01

    A moderately crowded stellar field in the cluster 47 Tuc {6 arcmin West of the cluster core} is observed every four months with the WFC. The first visit exercises the full suite of broad and narrow band imaging filters and sub-array modes; following visits observe with only the six most popular Cycle 18 filters in full-frame mode. The positions and magnitudes of objects will be used to monitor local and large scale variations in the plate scale and the sensitivity of the detectors and to derive an independent measure of the detector CTE. One exposure in each sub-array mode with the WFC will allow us to verify that photometry obtained in full-frame and in sub-array modes are repeatable to better than 1%. This test is important for the ACS Photometric Cross-Calibration program, which uses sub-array exposures. This program may receive additional orbits to investigate ORIENT-dependent geometric distortion, which motivates the ORIENT and BETWEEN requirement on the first visit.

  18. Suppression of spatially periodic patterns by dc voltage

    NASA Astrophysics Data System (ADS)

    Éber, Nándor; Salamon, Péter; Fekete, Balázs András; Karapinar, Ridvan; Krekhov, Alexei; Buka, Ágnes

    2016-04-01

    The effect of superposed dc and ac applied voltages on two types of spatially periodic instabilities in nematic liquid crystals, flexoelectric domains (FD), and electroconvection (EC) was studied. The onset characteristics, threshold voltages, and critical wave vectors were determined. We found that in general the superposition of driving with different time symmetries inhibits the pattern forming mechanisms for FD and EC as well. As a consequence, the onset extends to much higher voltages than the individual dc or ac thresholds. A dc-bias-induced reduction of the crossover frequency from the conductive to the dielectric EC regimes and a peculiar transition between two types of flexodomains with different wavelengths were detected. Direct measurements of the change of the electrical conductivity and its anisotropy, induced by the applied dc voltage component, showed that the dc bias substantially affects both parameters. Taking into account the experimentally detected variations of the conductivity in the linear stability analysis of the underlying nematohydrodynamic equations, a qualitative agreement with the experimental findings on the onset behavior of spatially periodic instabilities was obtained.

  19. A low voltage ``railgun''

    NASA Astrophysics Data System (ADS)

    Starr, Stanley O.; Youngquist, Robert C.; Cox, Robert B.

    2013-01-01

    Due to recent advances in solid-state switches and ultra-capacitors, it is now possible to construct a "railgun" that can operate at voltages below 20 V. Railguns typically operate above a thousand volts, generating huge currents for a few milliseconds to provide thousands of g's of acceleration to a small projectile. The low voltage railgun described herein operates for much longer time periods (tenths of seconds to seconds), has far smaller acceleration and speed, but can potentially propel a much larger object. The impetus for this development is to lay the groundwork for a possible ground-based supersonic launch track, but the resulting system may also have applications as a simple linear motor. The system would also be a useful teaching tool, requiring concepts from electrodynamics, mechanics, and electronics for its understanding, and is relatively straightforward to construct.

  20. Numerical and theoretical evaluations of AC losses for single and infinite numbers of superconductor strips with direct and alternating transport currents in external AC magnetic field

    NASA Astrophysics Data System (ADS)

    Kajikawa, K.; Funaki, K.; Shikimachi, K.; Hirano, N.; Nagaya, S.

    2010-11-01

    AC losses in a superconductor strip are numerically evaluated by means of a finite element method formulated with a current vector potential. The expressions of AC losses in an infinite slab that corresponds to a simple model of infinitely stacked strips are also derived theoretically. It is assumed that the voltage-current characteristics of the superconductors are represented by Bean’s critical state model. The typical operation pattern of a Superconducting Magnetic Energy Storage (SMES) coil with direct and alternating transport currents in an external AC magnetic field is taken into account as the electromagnetic environment for both the single strip and the infinite slab. By using the obtained results of AC losses, the influences of the transport currents on the total losses are discussed quantitatively.

  1. Increased voltage photovoltaic cell

    NASA Technical Reports Server (NTRS)

    Ross, B.; Bickler, D. B.; Gallagher, B. D. (Inventor)

    1985-01-01

    A photovoltaic cell, such as a solar cell, is provided which has a higher output voltage than prior cells. The improved cell includes a substrate of doped silicon, a first layer of silicon disposed on the substrate and having opposite doping, and a second layer of silicon carbide disposed on the first layer. The silicon carbide preferably has the same type of doping as the first layer.

  2. Insulators for high voltages

    SciTech Connect

    Looms, J.S.T.

    1987-01-01

    This book describes electrical insulators for high voltage applications. Topics considered include the insulating materials, the manufacture of wet process porcelain, the manufacture of tempered glass, the glass-fibre core, the polymeric housing, the common problem - terminating an insulator, mechanical constraints, the physics of pollution flashover, the physics of contamination, testing of insulators, conclusions from testing, remedies for flashover, insulators for special cases, interference and noise, and the insulator of the future.

  3. High voltage generator

    DOEpatents

    Schwemin, A. J.

    1959-03-17

    A generator for producing relatively large currents at high voltages is described. In general, the invention comprises a plurality of capacitors connected in series by a plurality of switches alternately disposed with the capacitors. The above-noted circuit is mounted for movement with respect to contact members and switch closure means so that a load device and power supply are connected across successive numbers of capacitors, while the other capacitors are successively charged with the same power supply.

  4. High Voltage Connector

    SciTech Connect

    Kurita, C.H.; /Fermilab

    1987-03-06

    The originally designed high voltage connectors were to be made of brass. However, if treated like a Bellevile spring with the initially given dimensions, the stresses of the connector when crimped were calculated to be much higher than the yield stress of brass. Since the flange and outer diameters of the connector are to remain small, it was necessary to alter the other dimensions and choice of material in order to bring down the stresses applied to the connector.

  5. HIGH VOLTAGE GENERATOR

    DOEpatents

    Schwemin, A.J.

    1959-03-17

    A generator is presented for producing relatively large currents at high voltages. In general, the invention comprises a plurality of capacitors connected in series by a plurality of switches alternately disposed with the capacitors. The circuit is mounted for movement with respect to contact members and switch closure means so that a load device and power supply are connected across successive numbers of capacitors, while the other capacitors are successively charged with the same power supply.

  6. Modified filter prevents conduction of microwave signals along high-voltage power supply leads

    NASA Technical Reports Server (NTRS)

    Mathison, R. P.

    1964-01-01

    Very lossy powdered iron material, in the lining of a polyester resin, replaces the dielectric material in the short coaxial transmission line of a simple filter. The lossy material absorbs microwave signals along high voltage power supply leads.

  7. AC photovoltaic module magnetic fields

    SciTech Connect

    Jennings, C.; Chang, G.J.; Reyes, A.B.; Whitaker, C.M.

    1997-12-31

    Implementation of alternating current (AC) photovoltaic (PV) modules, particularly for distributed applications such as PV rooftops and facades, may be slowed by public concern about electric and magnetic fields (EMF). This paper documents magnetic field measurements on an AC PV module, complementing EMF research on direct-current PV modules conducted by PG and E in 1993. Although not comprehensive, the PV EMF data indicate that 60 Hz magnetic fields (the EMF type of greatest public concern) from PV modules are comparable to, or significantly less than, those from household appliances. Given the present EMF research knowledge, AC PV module EMF may not merit considerable concern.

  8. HIGH VOLTAGE ION SOURCE

    DOEpatents

    Luce, J.S.

    1960-04-19

    A device is described for providing a source of molecular ions having a large output current and with an accelerated energy of the order of 600 kv. Ions are produced in an ion source which is provided with a water-cooled source grid of metal to effect maximum recombination of atomic ions to molecular ions. A very high accelerating voltage is applied to withdraw and accelerate the molecular ions from the source, and means are provided for dumping the excess electrons at the lowest possible potentials. An accelerating grid is placed adjacent to the source grid and a slotted, grounded accelerating electrode is placed adjacent to the accelerating grid. A potential of about 35 kv is maintained between the source grid and accelerating grid, and a potential of about 600 kv is maintained between the accelerating grid and accelerating electrode. In order to keep at a minimum the large number of oscillating electrons which are created when such high voltages are employed in the vicinity of a strong magnetic field, a plurality of high voltage cascaded shields are employed with a conventional electron dumping system being employed between each shield so as to dump the electrons at the lowest possible potential rather than at 600 kv.

  9. Improving thrust by pulse-induced breakdown enhancement in AC surface dielectric barrier discharge actuators for airflow control

    NASA Astrophysics Data System (ADS)

    Yan, Huijie; Yang, Liang; Qi, Xiaohua; Ren, Chunsheng

    2016-07-01

    The characteristics of a plate-to-plate AC surface dielectric barrier discharge (SDBD) actuator using the pulse-induced breakdown enhancing method are experimentally investigated. The encapsulated electrode is supplied with a sine high AC voltage, while the exposed electrode is feed by a synchronized pulse voltage. Based on the thrust force and power consumption measurements, a parametric study was performed using a positive pulse applied at the trough phase of the AC cycles in which the thrust force was observed to increase by about 100% to 300% and the efficiency up to about 100% compared with the AC-only supply conditions for different AC voltages within the tested range. The pulse-induced breakdown effect was analyzed from the electrical and light emission waveforms to reveal the underlying mechanism. The surface potential due to the charge deposition effect was also measured using a specially designed corona-like discharge potential probe. It is shown that the pulse-induced breakdown was able to cause a temporarily intensified local electric field to enhance the glow-like discharge and meanwhile increase the time-average surface potential in the region further downstream. The improvement in the force by the enhancement in the pulse-induced breakdown was mainly due to enhancements in the glow-like discharge and the surface potential increment, with the latter being more important when the AC voltage is higher.

  10. APPARATUS FOR REGULATING HIGH VOLTAGE

    DOEpatents

    Morrison, K.G.

    1951-03-20

    This patent describes a high-voltage regulator of the r-f type wherein the modulation of the r-f voltage is accomplished at a high level, resulting in good stabilization over a large range of load conditions.

  11. Electrical transport properties and current density - voltage characteristic of PVA-Ag nanocomposite film

    NASA Astrophysics Data System (ADS)

    Das, A. K.; Dutta, B.; Sinha, S.; Mukherjee, A.; Basu, S.; Meikap, A. K.

    2016-05-01

    Silver (Ag) nanoparticle and Polyvinyl alcohol (PVA) - Silver (Ag) composite have been prepared and its dielectric constant, ac conductivity, and current density-voltage characteristics have been studied, at and above room temperature. Here correlated barrier hopping found to be the dominant charge transport mechanism with maximum barrier height of 0.11 eV. The sample, under ±5 V applied voltage, show back to back Schottky diode behaviour.

  12. Automatic voltage-imbalance detector

    SciTech Connect

    Bobbett, R.E.; McCormick, J.B.; Kerwin, W.J.

    1981-05-20

    A device is described for indicating and preventing damage to voltage cells such as galvanic cells and fuel cells connected in series by detecting sequential voltages and comparing these voltages to adjacent voltage cells. The device is implemented by using operational amplifiers and switching circuitry is provided by transistors. The device can be utilized in battery powered electric vehicles to prevent galvanic cell damage and also in series connected fuel cells to prevent fuel cell damage.

  13. Variable frequency inverter for ac induction motors with torque, speed and braking control

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1975-01-01

    A variable frequency inverter was designed for driving an ac induction motor which varies the frequency and voltage to the motor windings in response to varying torque requirements for the motor so that the applied voltage amplitude and frequency are of optimal value for any motor load and speed requirement. The slip frequency of the motor is caused to vary proportionally to the torque and feedback is provided so that the most efficient operating voltage is applied to the motor. Winding current surge is limited and a controlled negative slip causes motor braking and return of load energy to a dc power source.

  14. System and method for monitoring and controlling stator winding temperature in a de-energized AC motor

    DOEpatents

    Lu, Bin; Luebke, Charles John; Habetler, Thomas G.; Zhang, Pinjia; Becker, Scott K.

    2011-12-27

    A system and method for measuring and controlling stator winding temperature in an AC motor while idling is disclosed. The system includes a circuit having an input connectable to an AC source and an output connectable to an input terminal of a multi-phase AC motor. The circuit further includes a plurality of switching devices to control current flow and terminal voltages in the multi-phase AC motor and a controller connected to the circuit. The controller is configured to activate the plurality of switching devices to create a DC signal in an output of the motor control device corresponding to an input to the multi-phase AC motor, determine or estimate a stator winding resistance of the multi-phase AC motor based on the DC signal, and estimate a stator temperature from the stator winding resistance. Temperature can then be controlled and regulated by DC injection into the stator windings.

  15. Three-Phase and Six-Phase AC at the Lab Bench

    ERIC Educational Resources Information Center

    Caplan, George M.

    2009-01-01

    Utility companies generate three-phase electric power, which consists of three sinusoidal voltages with phase angles of 0 degrees, 120 degrees, and 240 degrees. The ac generators described in most introductory textbooks are single-phase generators, so physics students are not likely to learn about three-phase power. I have developed a simple way…

  16. Charge-pump voltage converter

    DOEpatents

    Brainard, John P.; Christenson, Todd R.

    2009-11-03

    A charge-pump voltage converter for converting a low voltage provided by a low-voltage source to a higher voltage. Charge is inductively generated on a transfer rotor electrode during its transit past an inductor stator electrode and subsequently transferred by the rotating rotor to a collector stator electrode for storage or use. Repetition of the charge transfer process leads to a build-up of voltage on a charge-receiving device. Connection of multiple charge-pump voltage converters in series can generate higher voltages, and connection of multiple charge-pump voltage converters in parallel can generate higher currents. Microelectromechanical (MEMS) embodiments of this invention provide a small and compact high-voltage (several hundred V) voltage source starting with a few-V initial voltage source. The microscale size of many embodiments of this invention make it ideally suited for MEMS- and other micro-applications where integration of the voltage or charge source in a small package is highly desirable.

  17. The System Impact of Air-Conditioner Under-voltage Protection Schemes

    SciTech Connect

    Lu, Ning; Yang, Bo; Huang, Zhenyu; Bravo, Richard

    2009-03-31

    This paper presents simulation results of evaluating an under-voltage protection scheme designed to take stalled air-conditioner (a/c) units offline such that the slow voltage recovery phenomena can be solved on areas heavily loaded with a/c motors during summer peak periods. A three feeder test-bed has been first used to quantify the effectiveness of the protection scheme and the sensitivity of the under-voltage relay settings. Then two real system events of the Western US power grid have been studied to evaluate the area impact of the protection scheme proposed by Southern California Edison. The study demonstrates that by taking all or most of the stalled a/c unit offline, the feeder voltage will recover in a few seconds, much quicker than the tens of seconds that the standard thermal relays imbedded in the motors need to trip the units. The drawback of the control scheme is that after the voltage recover, it settled at a higher voltage than before the faults because a large chuck of load has been shed.

  18. Mechanism of biological effects observed in honey bees (Apis mellifera, L. ) hived under extra-high-voltage transmission lines: implications derived from bee exposure to simulated intense electric fields and shocks

    SciTech Connect

    Bindokas, V.P.; Gauger, J.R.; Greenberg, B.

    1988-01-01

    This work explores mechanisms for disturbance of honey bee colonies under a 765 kV, 60-Hz transmission line (electric (E) field = 7 kV/m) observed in previous studies. Proposed mechanisms fell into two categories: direct bee perception of enhanced in-hive E fields and perception of shock from induced currents. The adverse biological effects could be reproduced in simulations where only the worker bees were exposed to shock or to E field in elongated hive entranceways (= tunnels). We now report the results of full-scale experiments using the tunnel exposure scheme, which assesses the contribution of shock and intense E field to colony disturbance. Exposure of worker bees (1400 h) to 60-Hz E fields including 100 kV/m under moisture-free conditions within a nonconductive tunnel causes no deleterious affect on colony behavior. Exposure of bees in conductive (e.g., wet) tunnels produces bee disturbance, increased mortality, abnormal propolization, and possible impairment of colony growth. We propose that this substrate dependence of bee disturbance is the result of perception of shock from coupled body currents and enhanced current densities postulated to exist in the legs and thorax of bees on conductors. Similarly, disturbance occurs when bees are exposed to step-potential-induced currents. At 275-350 nA single bees are disturbed; at 600 nA bees begin abnormal propolization behavior; and stinging occurs at 900 nA. We conclude that biological effects seen in bee colonies under a transmission line are primarily the result of electric shock from induced hive currents. This evaluation is based on the limited effects of E-field exposure in tunnels, the observed disturbance thresholds caused by shocks in tunnels, and the ability of hives exposed under a transmission line to source currents 100-1,000 times the shock thresholds.

  19. Lateral separation of colloids or cells by dielectrophoresis augmented by AC electroosmosis.

    PubMed

    Zhou, Hao; White, Lee R; Tilton, Robert D

    2005-05-01

    Colloidal particles and biological cells are patterned and separated laterally adjacent to a micropatterned electrode array by applying AC electric fields that are principally oriented normally to the electrode array. This is demonstrated for yeast cells, red blood cells, and colloidal polystyrene particles of different sizes and zeta-potentials. The separation mechanism is observed experimentally to depend on the applied field frequency and voltage. At high frequencies, particles position themselves in a manner that is consistent with dielectrophoresis, while at low frequencies, the positioning is explained in terms of a strong coupling between gravity, the vertical component of the dielectrophoretic force, and the Stokes drag on particles induced by AC electroosmotic flow. Compared to high frequency dielectrophoretic separations, the low frequency separations are faster and require lower applied voltages. Furthermore, the AC electroosmosis coupling with dielectrophoresis may enable cell separations that are not feasible based on dielectrophoresis alone. PMID:15797412

  20. Methods, systems and apparatus for controlling operation of two alternating current (AC) machines

    DOEpatents

    Gallegos-Lopez, Gabriel; Nagashima, James M.; Perisic, Milun; Hiti, Silva

    2012-06-05

    A system is provided for controlling two alternating current (AC) machines via a five-phase PWM inverter module. The system comprises a first control loop, a second control loop, and a current command adjustment module. The current command adjustment module operates in conjunction with the first control loop and the second control loop to continuously adjust current command signals that control the first AC machine and the second AC machine such that they share the input voltage available to them without compromising the target mechanical output power of either machine. This way, even when the phase voltage available to either one of the machines decreases, that machine outputs its target mechanical output power.

  1. Power control for ac motor

    NASA Technical Reports Server (NTRS)

    Dabney, R. W. (Inventor)

    1984-01-01

    A motor controller employing a triac through which power is supplied to a motor is described. The open circuit voltage appearing across the triac controls the operation of a timing circuit. This timing circuit triggers on the triac at a time following turn off which varies inversely as a function of the amplitude of the open circuit voltage of the triac.

  2. Improved transistorized AC motor controller for battery powered urban electric passenger vehicles

    NASA Technical Reports Server (NTRS)

    Peak, S. C.

    1982-01-01

    An ac motor controller for an induction motor electric vehicle drive system was designed, fabricated, tested, evaluated, and cost analyzed. A vehicle performance analysis was done to establish the vehicle tractive effort-speed requirements. These requirements were then converted into a set of ac motor and ac controller requirements. The power inverter is a three-phase bridge using power Darlington transistors. The induction motor was optimized for use with an inverter power source. The drive system has a constant torque output to base motor speed and a constant horsepower output to maximum speed. A gear shifting transmission is not required. The ac controller was scaled from the base 20 hp (41 hp peak) at 108 volts dec to an expanded horsepower and battery voltage range. Motor reversal was accomplished by electronic reversal of the inverter phase sequence. The ac controller can also be used as a boost chopper battery charger. The drive system was tested on a dynamometer and results are presented. The current-controlled pulse width modulation control scheme yielded improved motor current waveforms. The ac controller favors a higher system voltage.

  3. AC operation and runaway electron behaviour in HT-7 tokamak

    NASA Astrophysics Data System (ADS)

    Lu, Hong-Wei; Hu, Li-Qun; Zhou, Rui-Jie; Lin, Shi-Yao; Zhong, Guo-Qiang; Wang, Shao-Feng; Chen, Kai-Yun; Xu, Ping; Zhang, Ji-Zong; Ling, Bi-Li; Mao, Song-Tao; Duan, Yan-Min

    2010-06-01

    Operation of HT-7 tokamak in a multicycle alternating square wave plasma current regime is reported. A set of AC operation experiments, including LHW heating to enhance plasma ionization during the current transition and current sustainment, is described. The behaviour of runaway electrons is analysed by four HXR detectors tangentially viewing the plasma in the equatorial plane, within energy ranges 0.3-1.2 MeV and 0.3-7 MeV, separately. High energy runaway electrons (~MeV) are found to circulate predominantly in the opposite direction to the plasma current, while the number of low energy runaway electrons (~tens to hundreds of keV) circulating along the plasma current is comparable to that in the direction opposite to the plasma current. AC operation with lower hybrid current drive (LHCD) is observed to have an additional benefit of suppressing the runaway electrons if the drop of the loop voltage is large enough.

  4. Determination of threshold and maximum operating electric stresses for selected high voltage insulations: Investigation of aged polymeric dielectric cable. Final report

    SciTech Connect

    Eager, G.S. Jr.; Seman, G.W.; Fryszczyn, B.

    1995-11-01

    Based on the successful completion of the extensive research project DOE/ET/29303-1 February 1982 to develop a new method for the determination of threshold voltage in XLPE and EPR insulated cables, tests were initiated to establish the maximum safe operating voltage stresses of crosslinked polyethylene insulated cables that become wet when they operate in a moist environment. The present report covers the measurement of the threshold voltage, the a.c. breakdown voltage and the impulse breakdown voltage of XLPE cable after undergoing accelerated laboratory aging in water. Model and 15 kV XLPE cables were manufactured in commercial equipment using state-of-the-art semiconducting shields and XLPE insulation. The threshold voltage, a.c. voltage breakdown and impulse voltage breakdown of the model cables were determined before aging, after aging one week and after aging 26 weeks. The model cable, following 26 weeks aging, was dried by passing dry gas through the conductor interstices which removed moisture from the cable. The threshold voltage, the a.c. voltage breakdown and the impulse voltage breakdown of the XLPE model cable after drying was measured.

  5. Research and Experiments on a Unipolar Capacitive Voltage Sensor.

    PubMed

    Zhou, Qiang; He, Wei; Li, Songnong; Hou, Xingzhe

    2015-08-21

    Voltage sensors are an important part of the electric system. In service, traditional voltage sensors need to directly contact a high-voltage charged body. Sensors involve a large volume, complex insulation structures, and high design costs. Typically an iron core structure is adopted. As a result, ferromagnetic resonance can occur easily during practical application. Moreover, owing to the multilevel capacitor divider, the sensor cannot reflect the changes of measured voltage in time. Based on the electric field coupling principle, this paper designs a new voltage sensor; the unipolar structure design solves many problems of traditional voltage sensors like the great insulation design difficulty and high costs caused by grounding electrodes. A differential signal input structure is adopted for the detection circuit, which effectively restrains the influence of the common-mode interference signal. Through sensor modeling, simulation and calculations, the structural design of the sensor electrode was optimized, miniaturization of the sensor was realized, the voltage division ratio of the sensor was enhanced, and the phase difference of sensor measurement was weakened. The voltage sensor is applied to a single-phase voltage class line of 10 kV for testing. According to the test results, the designed sensor is able to meet the requirements of accurate and real-time measurement for voltage of the charged conductor as well as to provide a new method for electricity larceny prevention and on-line monitoring of the power grid in an electric system. Therefore, it can satisfy the development demands of the smart power grid.

  6. Research and Experiments on a Unipolar Capacitive Voltage Sensor

    PubMed Central

    Zhou, Qiang; He, Wei; Li, Songnong; Hou, Xingzhe

    2015-01-01

    Voltage sensors are an important part of the electric system. In service, traditional voltage sensors need to directly contact a high-voltage charged body. Sensors involve a large volume, complex insulation structures, and high design costs. Typically an iron core structure is adopted. As a result, ferromagnetic resonance can occur easily during practical application. Moreover, owing to the multilevel capacitor divider, the sensor cannot reflect the changes of measured voltage in time. Based on the electric field coupling principle, this paper designs a new voltage sensor; the unipolar structure design solves many problems of traditional voltage sensors like the great insulation design difficulty and high costs caused by grounding electrodes. A differential signal input structure is adopted for the detection circuit, which effectively restrains the influence of the common-mode interference signal. Through sensor modeling, simulation and calculations, the structural design of the sensor electrode was optimized, miniaturization of the sensor was realized, the voltage division ratio of the sensor was enhanced, and the phase difference of sensor measurement was weakened. The voltage sensor is applied to a single-phase voltage class line of 10 kV for testing. According to the test results, the designed sensor is able to meet the requirements of accurate and real-time measurement for voltage of the charged conductor as well as to provide a new method for electricity larceny prevention and on-line monitoring of the power grid in an electric system. Therefore, it can satisfy the development demands of the smart power grid. PMID:26307992

  7. Theory of the ac spin-valve effect.

    PubMed

    Kochan, Denis; Gmitra, Martin; Fabian, Jaroslav

    2011-10-21

    The spin-valve complex magnetoimpedance of symmetric ferromagnet-normal-metal-ferromagnet junctions is investigated within the drift-diffusion (standard) model of spin injection. The ac magnetoresistance-the real part difference of the impedances of the parallel and antiparallel magnetization configurations-exhibits an overall damped oscillatory behavior, as an interplay of the diffusion and spin relaxation times. In wide junctions the ac magnetoresistance oscillates between positive and negative values, reflecting resonant amplification and depletion of the spin accumulation, while the line shape for thin tunnel junctions is predicted to be purely Lorentzian. The ac spin-valve effect could be a technique to extract spin transport and spin relaxation parameters in the absence of a magnetic field and for a fixed sample size. PMID:22107552

  8. Input-current shaped ac to dc converters

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The problem of achieving near unity power factor while supplying power to a dc load from a single phase ac source of power is examined. Power processors for this application must perform three functions: input current shaping, energy storage, and output voltage regulation. The methods available for performing each of these three functions are reviewed. Input current shaping methods are either active or passive, with the active methods divided into buck-like and boost-like techniques. In addition to large reactances, energy storage methods include resonant filters, active filters, and active storage schemes. Fast voltage regulation can be achieved by post regulation or by supplementing the current shaping topology with an extra switch. Some indications of which methods are best suited for particular applications concludes the discussion.

  9. An AC drive system for a battery driven moped

    SciTech Connect

    Nandi, S.; Saha, S.; Sharon, M.; Sundersingh, V.P.

    1995-12-31

    A petrol driven moped is converted to an electric one by replacing the petrol engine by a three phase 1.5 HR, AC squirrel cage induction motor drive system. The motor voltage rating selected is 200 V to keep the DC boost voltage level to a reasonable value.f the power source used is a high energy density, 24 V, 110 Ah, Ni-Zn battery. A modified indirect current controlled step-up chopper as well as a standard push-pull DC-DC boost converter is studied for the boost scheme. A simple three phase quasi-square wave inverter is designed along with suitable protection for driving the motor. Successful trial test of the system has been conducted at the laboratory.

  10. Development of AC and DC Power Supply Direct Interface Converter

    NASA Astrophysics Data System (ADS)

    Kato, Koji; Itoh, Jun-Ichi

    This paper proposes a novel control method for a direct interface converter for management of the energy flow in either an AC or DC supply. The proposed converter is constructed based on an indirect matrix converter. Therefore a proposed control strategy is based on an indirect control method with a triangular carrier wave. The basic operation of the proposed control method is confirmed by experimental results. In addition, this paper also proposes a commutation error compensation method of an output voltage error and an input current error for an indirect matrix converter. In the proposed method, the output voltage and input current error by the commutation can be compensated at the same time, because the PWM pulse of each switch is directly compensated. The validity of the proposed method is confirmed by experimental results. Those results prove that the proposed compensation method can decrease total harmonic distortion (THD) of the input and output current.

  11. Isomerically Pure Tetramethylrhodamine Voltage Reporters.

    PubMed

    Deal, Parker E; Kulkarni, Rishikesh U; Al-Abdullatif, Sarah H; Miller, Evan W

    2016-07-27

    We present the design, synthesis, and application of a new family of fluorescent voltage indicators based on isomerically pure tetramethylrhodamines. These new Rhodamine Voltage Reporters, or RhoVRs, use photoinduced electron transfer (PeT) as a trigger for voltage sensing, display excitation and emission profiles in the green to orange region of the visible spectrum, demonstrate high sensitivity to membrane potential changes (up to 47% ΔF/F per 100 mV), and employ a tertiary amide derived from sarcosine, which aids in membrane localization and simultaneously simplifies the synthetic route to the voltage sensors. The most sensitive of the RhoVR dyes, RhoVR 1, features a methoxy-substituted diethylaniline donor and phenylenevinylene molecular wire at the 5'-position of the rhodamine aryl ring, exhibits the highest voltage sensitivity to date for red-shifted PeT-based voltage sensors, and is compatible with simultaneous imaging alongside green fluorescent protein-based indicators. The discoveries that sarcosine-based tertiary amides in the context of molecular-wire voltage indicators prevent dye internalization and 5'-substituted voltage indicators exhibit improved voltage sensitivity should be broadly applicable to other types of PeT-based voltage-sensitive fluorophores. PMID:27428174

  12. Transistor voltage comparator performs own sensing

    NASA Technical Reports Server (NTRS)

    Cliff, R. A.

    1965-01-01

    Detection of the highest voltage input among a group of varying voltage inputs is accomplished by a transistorized voltage comparison circuit. The collector circuits of the transistors perform the sensing function. Input voltage levels are governed by the transistors.

  13. Restrictions on TWT Helix Voltage Ripple for Acceptable Notch Filter Performance

    SciTech Connect

    Hyslop, B.

    1984-12-01

    An ac ripple on the helix voltage of the 1-2 GHz TWT's creates FM sidebands that cause amplitude and phase modulation of the microwave TWT output signal. A limit of 16 volts peak-to-peak is required for acceptable superconducting notch filter performance.

  14. Phase-sensitive detection of spin pumping via the ac inverse spin Hall effect.

    PubMed

    Weiler, Mathias; Shaw, Justin M; Nembach, Hans T; Silva, Thomas J

    2014-10-10

    We use a phase-sensitive, quantitative technique to separate inductive and ac inverse spin Hall effect (ISHE) voltages observed in Ni(81)Fe(19)/normal metal multilayers under the condition of ferromagnetic resonance. For Ni(81)Fe(19)/Pt thin film bilayers and at microwave frequencies from 7 to 20 GHz, we observe an ac ISHE magnitude that is much larger than that expected from the dc spin Hall angle Θ(SH)(Pt) = 0.1. Furthermore, at these frequencies, we find an unexpected, ≈ 110° phase of the ac ISHE signal relative to the in-plane component of the resonant magnetization precession. We attribute our findings to a dominant intrinsic ac ISHE in Pt.

  15. Pulse shaping with transmission lines

    DOEpatents

    Wilcox, R.B.

    1985-08-15

    A method and apparatus for forming shaped voltage pulses uses passive reflection from a transmission line with nonuniform impedance. The impedance of the reflecting line varies with length in accordance with the desired pulse shape. A high voltage input pulse is transmitted to the reflecting line. A reflected pulse is produced having the desired shape and is transmitted by pulse removal means to a load. Light activated photoconductive switches made of silicon can be utilized. The pulse shaper can be used to drive a Pockels cell to produce shaped optical pulses.

  16. Pulse shaping with transmission lines

    DOEpatents

    Wilcox, Russell B.

    1987-01-01

    A method and apparatus for forming shaped voltage pulses uses passive reflection from a transmission line with nonuniform impedance. The impedance of the reflecting line varies with length in accordance with the desired pulse shape. A high voltage input pulse is transmitted to the reflecting line. A reflected pulse is produced having the desired shape and is transmitted by pulse removal means to a load. Light activated photoconductive switches made of silicon can be utilized. The pulse shaper can be used to drive a Pockels cell to produce shaped optical pulses.

  17. Generator voltage stabilisation for series-hybrid electric vehicles.

    PubMed

    Stewart, P; Gladwin, D; Stewart, J; Cowley, R

    2008-04-01

    This paper presents a controller for use in speed control of an internal combustion engine for series-hybrid electric vehicle applications. Particular reference is made to the stability of the rectified DC link voltage under load disturbance. In the system under consideration, the primary power source is a four-cylinder normally aspirated gasoline internal combustion engine, which is mechanically coupled to a three-phase permanent magnet AC generator. The generated AC voltage is subsequently rectified to supply a lead-acid battery, and permanent magnet traction motors via three-phase full bridge power electronic inverters. Two complementary performance objectives exist. Firstly to maintain the internal combustion engine at its optimal operating point, and secondly to supply a stable 42 V supply to the traction drive inverters. Achievement of these goals minimises the transient energy storage requirements at the DC link, with a consequent reduction in both weight and cost. These objectives imply constant velocity operation of the internal combustion engine under external load disturbances and changes in both operating conditions and vehicle speed set-points. An electronically operated throttle allows closed loop engine velocity control. System time delays and nonlinearities render closed loop control design extremely problematic. A model-based controller is designed and shown to be effective in controlling the DC link voltage, resulting in the well-conditioned operation of the hybrid vehicle. PMID:18262528

  18. A high voltage method for measuring low capacitance for tomography.

    PubMed

    Lu, Decai; Shao, Fuqun; Guo, Zhiheng

    2009-05-01

    Low capacitance measurement is involved in many industrial applications, especially in the applications of electrical capacitance tomography (ECT). Most of the low capacitance measurement circuits employ an ac-based method or a charge/discharge method because of high sensitivity, high resolution, and immunity to stray capacitance; and its excitation or charge voltage are not more than 20 V. When ECT techniques for large industrial equipment such as blast furnaces or grain barns are explored, the existing methods for measuring low capacitance have some limitations. This paper proposes a high excitation voltage ac-based method for measuring low capacitance to improve the resolution of measurement. The method uses a high excitation voltage of several hundred volts and a transformer ratio arms as the C/V transducer. Experimental results indicate that the new method has a resolution of 0.005 fF, a good stability (about 0.003 fF over 4 h) and linearity (0.9992). PMID:19485513

  19. A high voltage method for measuring low capacitance for tomography.

    PubMed

    Lu, Decai; Shao, Fuqun; Guo, Zhiheng

    2009-05-01

    Low capacitance measurement is involved in many industrial applications, especially in the applications of electrical capacitance tomography (ECT). Most of the low capacitance measurement circuits employ an ac-based method or a charge/discharge method because of high sensitivity, high resolution, and immunity to stray capacitance; and its excitation or charge voltage are not more than 20 V. When ECT techniques for large industrial equipment such as blast furnaces or grain barns are explored, the existing methods for measuring low capacitance have some limitations. This paper proposes a high excitation voltage ac-based method for measuring low capacitance to improve the resolution of measurement. The method uses a high excitation voltage of several hundred volts and a transformer ratio arms as the C/V transducer. Experimental results indicate that the new method has a resolution of 0.005 fF, a good stability (about 0.003 fF over 4 h) and linearity (0.9992).

  20. Generator voltage stabilisation for series-hybrid electric vehicles.

    PubMed

    Stewart, P; Gladwin, D; Stewart, J; Cowley, R

    2008-04-01

    This paper presents a controller for use in speed control of an internal combustion engine for series-hybrid electric vehicle applications. Particular reference is made to the stability of the rectified DC link voltage under load disturbance. In the system under consideration, the primary power source is a four-cylinder normally aspirated gasoline internal combustion engine, which is mechanically coupled to a three-phase permanent magnet AC generator. The generated AC voltage is subsequently rectified to supply a lead-acid battery, and permanent magnet traction motors via three-phase full bridge power electronic inverters. Two complementary performance objectives exist. Firstly to maintain the internal combustion engine at its optimal operating point, and secondly to supply a stable 42 V supply to the traction drive inverters. Achievement of these goals minimises the transient energy storage requirements at the DC link, with a consequent reduction in both weight and cost. These objectives imply constant velocity operation of the internal combustion engine under external load disturbances and changes in both operating conditions and vehicle speed set-points. An electronically operated throttle allows closed loop engine velocity control. System time delays and nonlinearities render closed loop control design extremely problematic. A model-based controller is designed and shown to be effective in controlling the DC link voltage, resulting in the well-conditioned operation of the hybrid vehicle.

  1. High voltage feedthrough bushing

    DOEpatents

    Brucker, John P.

    1993-01-01

    A feedthrough bushing for a high voltage diode provides for using compression sealing for all sealing surfaces. A diode assembly includes a central conductor extending through the bushing and a grading ring assembly circumferentially surrounding and coaxial with the central conductor. A flexible conductive plate extends between and compressively seals against the central conductor and the grading ring assembly, wherein the flexibility of the plate allows inner and outer portions of the plate to axially translate for compression sealing against the central conductor and the grading ring assembly, respectively. The inner portion of the plate is bolted to the central conductor for affecting sealing. A compression beam is also bolted to the central conductor and engages the outer portion of the plate to urge the outer portion toward the grading ring assembly to obtain compression sealing therebetween.

  2. Analyzing effects of aperture size and applied voltage on the response time

    NASA Astrophysics Data System (ADS)

    Kim, YooKwang; Lee, Jin Su; Won, Yong Hyub

    2016-03-01

    Electrowetting lens is a promising technique for non-mechanical vari-focal lens, because of fast response time, wide expressible diopter, and etc. Although electrowetting related papers are actively published, no one did not clearly define the relationship among electrowetting parameters, especially in AC driven case. Analysis for AC voltage driving is needed because AC electrowetting has many advantages like low hysteresis and short settling time. In this experiment we confirmed that the response time depends on aperture size and applied voltage. Response time measurement for lens aperture of 200-1000um and applied voltage of 0-70V with 1kHz frequency was conducted. Experimental data was compared with simulation result by COMSOL Multiphysics program with the same condition, and they correspond with each other well. As voltage increases, the overshoot height becomes higher, so it has longer oscillation and settling time. On the other hand if aperture size decreases, the surface tension of lens wall could be delivered effectively to the center region of meniscus, so it has less oscillation and shorter settling time. The result was that in 500um aperture no more than 30V should be applied to ensure 1ms response time. In 200um aperture, the voltage limit is disappeared.

  3. Non-contact current and voltage sensing method using a clamshell housing and a ferrite cylinder

    DOEpatents

    Carpenter, Gary D.; El-Essawy, Wael; Ferreira, Alexandre Peixoto; Keller, Thomas Walter; Rubio, Juan C.; Schappert, Michael

    2016-04-26

    A method of measurement using a detachable current and voltage sensor provides an isolated and convenient technique for to measuring current passing through a conductor such as an AC branch circuit wire, as well as providing an indication of an electrostatic potential on the wire, which can be used to indicate the phase of the voltage on the wire, and optionally a magnitude of the voltage. The device includes a housing that contains the current and voltage sensors, which may be a ferrite cylinder with a hall effect sensor disposed in a gap along the circumference to measure current, or alternative a winding provided through the cylinder along its axis and a capacitive plate or wire disposed adjacent to, or within, the ferrite cylinder to provide the indication of the voltage.

  4. Non-contact current and voltage sensor having detachable housing incorporating multiple ferrite cylinder portions

    DOEpatents

    Carpenter, Gary D.; El-Essawy, Wael; Ferreira, Alexandre Peixoto; Keller, Thomas Walter; Rubio, Juan C.; Schappert, Michael A.

    2016-04-26

    A detachable current and voltage sensor provides an isolated and convenient device to measure current passing through a conductor such as an AC branch circuit wire, as well as providing an indication of an electrostatic potential on the wire, which can be used to indicate the phase of the voltage on the wire, and optionally a magnitude of the voltage. The device includes a housing formed from two portions that mechanically close around the wire and that contain the current and voltage sensors. The current sensor is a ferrite cylinder formed from at least three portions that form the cylinder when the sensor is closed around the wire with a hall effect sensor disposed in a gap between two of the ferrite portions along the circumference to measure current. A capacitive plate or wire is disposed adjacent to, or within, the ferrite cylinder to provide the indication of the voltage.

  5. Achieving High Performance in AC-Field Driven Organic Light Sources

    PubMed Central

    Xu, Junwei; Carroll, David L.; Smith, Gregory M.; Dun, Chaochao; Cui, Yue

    2016-01-01

    Charge balance in organic light emitting structures is essential to simultaneously achieving high brightness and high efficiency. In DC-driven organic light emitting devices (OLEDs), this is relatively straight forward. However, in the newly emerging, capacitive, field-activated AC-driven organic devices, charge balance can be a challenge. In this work we introduce the concept of gating the compensation charge in AC-driven organic devices and demonstrate that this can result in exceptional increases in device performance. To do this we replace the insulator layer in a typical field-activated organic light emitting device with a nanostructured, wide band gap semiconductor layer. This layer acts as a gate between the emitter layer and the voltage contact. Time resolved device characterization shows that, at high-frequencies (over 40 kHz), the semiconductor layer allows for charge accumulation in the forward bias, light generating part of the AC cycle and charge compensation in the negative, quiescent part of the AC cycle. Such gated AC organic devices can achieve a non-output coupled luminance of 25,900 cd/m2 with power efficiencies that exceed both the insulator-based AC devices and OLEDs using the same emitters. This work clearly demonstrates that by realizing balanced management of charge, AC-driven organic light emitting devices may well be able to rival today’s OLEDs in performance. PMID:27063414

  6. Achieving High Performance in AC-Field Driven Organic Light Sources.

    PubMed

    Xu, Junwei; Carroll, David L; Smith, Gregory M; Dun, Chaochao; Cui, Yue

    2016-04-11

    Charge balance in organic light emitting structures is essential to simultaneously achieving high brightness and high efficiency. In DC-driven organic light emitting devices (OLEDs), this is relatively straight forward. However, in the newly emerging, capacitive, field-activated AC-driven organic devices, charge balance can be a challenge. In this work we introduce the concept of gating the compensation charge in AC-driven organic devices and demonstrate that this can result in exceptional increases in device performance. To do this we replace the insulator layer in a typical field-activated organic light emitting device with a nanostructured, wide band gap semiconductor layer. This layer acts as a gate between the emitter layer and the voltage contact. Time resolved device characterization shows that, at high-frequencies (over 40 kHz), the semiconductor layer allows for charge accumulation in the forward bias, light generating part of the AC cycle and charge compensation in the negative, quiescent part of the AC cycle. Such gated AC organic devices can achieve a non-output coupled luminance of 25,900 cd/m(2) with power efficiencies that exceed both the insulator-based AC devices and OLEDs using the same emitters. This work clearly demonstrates that by realizing balanced management of charge, AC-driven organic light emitting devices may well be able to rival today's OLEDs in performance.

  7. A feed-forward controlled AC-DC boost converter for biomedical implants.

    PubMed

    Jiang, Hao; Lan, Di; Lin, Dahsien; Zhang, Junmin; Liou, Shyshenq; Shahnasser, Hamid; Shen, Ming; Harrison, Michael; Roy, Shuvo

    2012-01-01

    Miniaturization is important to make implants clinic friendly. Wireless power transfer is an essential technology to miniaturize implants by reducing their battery size or completely eliminating their batteries. Traditionally, a pair of inductively-coupled coils operating at radio-frequency (RF) is employed to deliver electrical power wirelessly. In this approach, a rectifier is needed to convert the received RF power to a stable DC one. To achieve high efficiency, the induced voltage of the receiving coil must be much higher than the turn-on voltage of the rectifying diode (which could be an active circuit for low turn-on voltage) [1]. In order to have a high induced voltage, the size of the receiving coil often is significantly larger than rest of the implant. A rotating magnets based wireless power transfer has been demonstrated to deliver the same amount of power at much lower frequency (around 100 Hz) because of the superior magnetic strength produced by rare-earth magnets [2]. Taking the advantage of the low operating frequency, an innovative feed-forward controlled AC to DC boost converter has been demonstrated for the first time to accomplish the following two tasks simultaneously: (1) rectifying the AC power whose amplitude (500 mV) is less than the rectifier's turn-on voltage (1.44 V) and (2) boosting the DC output voltage to a much higher level (5 V). Within a range, the output DC voltage can be selected by the control circuit. The standard deviation of the output DC voltage is less than 2.1% of its mean. The measured load regulation is 0.4 V/kΩ. The estimated conversion efficiency excluding the power consumption of the control circuits reaches 75%. The converter in this paper has the potential to reduce the size of the receiving coil and yet achieve desirable DC output voltage for powering biomedical implants. PMID:23366230

  8. The ac53, ac78, ac101, and ac103 Genes Are Newly Discovered Core Genes in the Family Baculoviridae

    PubMed Central

    Garavaglia, Matías Javier; Miele, Solange Ana Belén; Iserte, Javier Alonso; Belaich, Mariano Nicolás

    2012-01-01

    The family Baculoviridae is a large group of insect viruses containing circular double-stranded DNA genomes of 80 to 180 kbp, which have broad biotechnological applications. A key feature to understand and manipulate them is the recognition of orthology. However, the differences in gene contents and evolutionary distances among the known members of this family make it difficult to assign sequence orthology. In this study, the genome sequences of 58 baculoviruses were analyzed, with the aim to detect previously undescribed core genes because of their remote homology. A routine based on Multi PSI-Blast/tBlastN and Multi HaMStR allowed us to detect 31 of 33 accepted core genes and 4 orthologous sequences in the Baculoviridae which were not described previously. Our results show that the ac53, ac78, ac101 (p40), and ac103 (p48) genes have orthologs in all genomes and should be considered core genes. Accordingly, there are 37 orthologous genes in the family Baculoviridae. PMID:22933288

  9. Semiconductor ac static power switch

    NASA Technical Reports Server (NTRS)

    Vrancik, J.

    1968-01-01

    Semiconductor ac static power switch has long life and high reliability, contains no moving parts, and operates satisfactorily in severe environments, including high vibration and shock conditions. Due to their resistance to shock and vibration, static switches are used where accidental switching caused by mechanical vibration or shock cannot be tolerated.

  10. High-voltage pulsed generator for dynamic fragmentation of rocks.

    PubMed

    Kovalchuk, B M; Kharlov, A V; Vizir, V A; Kumpyak, V V; Zorin, V B; Kiselev, V N

    2010-10-01

    A portable high-voltage (HV) pulsed generator has been designed for rock fragmentation experiments. The generator can be used also for other technological applications. The installation consists of low voltage block, HV block, coaxial transmission line, fragmentation chamber, and control system block. Low voltage block of the generator, consisting of a primary capacitor bank (300 μF) and a thyristor switch, stores pulse energy and transfers it to the HV block. The primary capacitor bank stores energy of 600 J at the maximum charging voltage of 2 kV. HV block includes HV pulsed step up transformer, HV capacitive storage, and two electrode gas switch. The following technical parameters of the generator were achieved: output voltage up to 300 kV, voltage rise time of ∼50 ns, current amplitude of ∼6 kA with the 40 Ω active load, and ∼20 kA in a rock fragmentation regime (with discharge in a rock-water mixture). Typical operation regime is a burst of 1000 pulses with a frequency of 10 Hz. The operation process can be controlled within a wide range of parameters. The entire installation (generator, transmission line, treatment chamber, and measuring probes) is designed like a continuous Faraday's cage (complete shielding) to exclude external electromagnetic perturbations.

  11. High-voltage pulsed generator for dynamic fragmentation of rocks

    NASA Astrophysics Data System (ADS)

    Kovalchuk, B. M.; Kharlov, A. V.; Vizir, V. A.; Kumpyak, V. V.; Zorin, V. B.; Kiselev, V. N.

    2010-10-01

    A portable high-voltage (HV) pulsed generator has been designed for rock fragmentation experiments. The generator can be used also for other technological applications. The installation consists of low voltage block, HV block, coaxial transmission line, fragmentation chamber, and control system block. Low voltage block of the generator, consisting of a primary capacitor bank (300 μF) and a thyristor switch, stores pulse energy and transfers it to the HV block. The primary capacitor bank stores energy of 600 J at the maximum charging voltage of 2 kV. HV block includes HV pulsed step up transformer, HV capacitive storage, and two electrode gas switch. The following technical parameters of the generator were achieved: output voltage up to 300 kV, voltage rise time of ˜50 ns, current amplitude of ˜6 kA with the 40 Ω active load, and ˜20 kA in a rock fragmentation regime (with discharge in a rock-water mixture). Typical operation regime is a burst of 1000 pulses with a frequency of 10 Hz. The operation process can be controlled within a wide range of parameters. The entire installation (generator, transmission line, treatment chamber, and measuring probes) is designed like a continuous Faraday's cage (complete shielding) to exclude external electromagnetic perturbations.

  12. High-voltage pulsed generator for dynamic fragmentation of rocks.

    PubMed

    Kovalchuk, B M; Kharlov, A V; Vizir, V A; Kumpyak, V V; Zorin, V B; Kiselev, V N

    2010-10-01

    A portable high-voltage (HV) pulsed generator has been designed for rock fragmentation experiments. The generator can be used also for other technological applications. The installation consists of low voltage block, HV block, coaxial transmission line, fragmentation chamber, and control system block. Low voltage block of the generator, consisting of a primary capacitor bank (300 μF) and a thyristor switch, stores pulse energy and transfers it to the HV block. The primary capacitor bank stores energy of 600 J at the maximum charging voltage of 2 kV. HV block includes HV pulsed step up transformer, HV capacitive storage, and two electrode gas switch. The following technical parameters of the generator were achieved: output voltage up to 300 kV, voltage rise time of ∼50 ns, current amplitude of ∼6 kA with the 40 Ω active load, and ∼20 kA in a rock fragmentation regime (with discharge in a rock-water mixture). Typical operation regime is a burst of 1000 pulses with a frequency of 10 Hz. The operation process can be controlled within a wide range of parameters. The entire installation (generator, transmission line, treatment chamber, and measuring probes) is designed like a continuous Faraday's cage (complete shielding) to exclude external electromagnetic perturbations. PMID:21034090

  13. Vortex ratchet reversal in an asymmetric washboard pinning potential subject to combined dc and ac stimuli.

    PubMed

    Shklovskij, Valerij A; Sosedkin, Vladimir V; Dobrovolskiy, Oleksandr V

    2014-01-15

    The mixed-state resistive response of a superconductor thin film with an asymmetric washboard pinning potential subject to superimposed dc and ac currents of arbitrary amplitudes and frequency at finite temperature is theoretically investigated. The problem is considered in the single-vortex approximation, relying upon the exact solution of the Langevin equation in terms of a matrix continued fraction. The dc voltage response and the absorbed power in ac response are analyzed as functions of dc bias and ac current amplitude and frequency in a wide range of corresponding dimensionless parameters. Predictions are made of (i) a reversal of the rectified voltage at small dc biases and strong ac drives and (ii) a non-monotonic enhancement of the absorbed power in the nonlinear ac response at far sub-depinning frequencies. It is elucidated how and why both these effects appear due to the competition of the fixed internal and the tunable, dc bias-induced external asymmetry of the potential as the only reason. This is distinct from other scenarios used for explaining the vortex ratchet reversal effect so far. PMID:24304564

  14. Soliton production with nonlinear homogeneous lines

    DOE PAGES

    Elizondo-Decanini, Juan M.; Coleman, Phillip D.; Moorman, Matthew W.; Petney, Sharon Joy Victor; Dudley, Evan C.; Youngman, Kevin; Penner, Tim Dwight; Fang, Lu; Myers, Katherine M.

    2015-11-24

    Low- and high-voltage Soliton waves were produced and used to demonstrate collision and compression using diode-based nonlinear transmission lines. Experiments demonstrate soliton addition and compression using homogeneous nonlinear lines. We built the nonlinear lines using commercially available diodes. These diodes are chosen after their capacitance versus voltage dependence is used in a model and the line design characteristics are calculated and simulated. Nonlinear ceramic capacitors are then used to demonstrate high-voltage pulse amplification and compression. The line is designed such that a simple capacitor discharge, input signal, develops soliton trains in as few as 12 stages. We also demonstrated outputmore » voltages in excess of 40 kV using Y5V-based commercial capacitors. The results show some key features that determine efficient production of trains of solitons in the kilovolt range.« less

  15. Soliton production with nonlinear homogeneous lines

    SciTech Connect

    Elizondo-Decanini, Juan M.; Coleman, Phillip D.; Moorman, Matthew W.; Petney, Sharon Joy Victor; Dudley, Evan C.; Youngman, Kevin; Penner, Tim Dwight; Fang, Lu; Myers, Katherine M.

    2015-11-24

    Low- and high-voltage Soliton waves were produced and used to demonstrate collision and compression using diode-based nonlinear transmission lines. Experiments demonstrate soliton addition and compression using homogeneous nonlinear lines. We built the nonlinear lines using commercially available diodes. These diodes are chosen after their capacitance versus voltage dependence is used in a model and the line design characteristics are calculated and simulated. Nonlinear ceramic capacitors are then used to demonstrate high-voltage pulse amplification and compression. The line is designed such that a simple capacitor discharge, input signal, develops soliton trains in as few as 12 stages. We also demonstrated output voltages in excess of 40 kV using Y5V-based commercial capacitors. The results show some key features that determine efficient production of trains of solitons in the kilovolt range.

  16. Temperature controlled high voltage regulator

    DOEpatents

    Chiaro, Jr., Peter J.; Schulze, Gerald K.

    2004-04-20

    A temperature controlled high voltage regulator for automatically adjusting the high voltage applied to a radiation detector is described. The regulator is a solid state device that is independent of the attached radiation detector, enabling the regulator to be used by various models of radiation detectors, such as gas flow proportional radiation detectors.

  17. Voltage sensor and dielectric material

    DOEpatents

    Yakymyshyn, Christopher Paul; Yakymyshyn, Pamela Jane; Brubaker, Michael Allen

    2006-10-17

    A voltage sensor is described that consists of an arrangement of impedance elements. The sensor is optimized to provide an output ratio that is substantially immune to changes in voltage, temperature variations or aging. Also disclosed is a material with a large and stable dielectric constant. The dielectric constant can be tailored to vary with position or direction in the material.

  18. Transient voltage oscillations in coils

    SciTech Connect

    Chowdhuri, P.

    1985-01-01

    Magnet coils may be excited into internal voltage oscillations by transient voltages. Such oscillations may electrically stress the magnet's dielectric components to many times its normal stress. This may precipitate a dielectric failure, and the attendant prolonged loss of service and costly repair work. Therefore, it is important to know the natural frequencies of oscillations of a magnet during the design stage, and to determine whether the expected switching transient voltages can excite the magnet into high-voltage internal oscillations. The series capacitance of a winding significantly affects its natural frequencies. However, the series capacitance is difficult to calculate, because it may comprise complex capacitance network, consisting of intra- and inter-coil turn-to-turn capacitances of the coil sections. A method of calculating the series capacitance of a winding is proposed. This method is rigorous but simple to execute. The time-varying transient voltages along the winding are also calculated.

  19. Intermodulation electrostatic force microscopy for imaging surface photo-voltage

    SciTech Connect

    Borgani, Riccardo Forchheimer, Daniel; Thorén, Per-Anders; Haviland, David B.; Bergqvist, Jonas; Inganäs, Olle

    2014-10-06

    We demonstrate an alternative to Kelvin Probe Force Microscopy for imaging surface potential. The open-loop, single-pass technique applies a low-frequency AC voltage to the atomic force microscopy tip while driving the cantilever near its resonance frequency. Frequency mixing due to the nonlinear capacitance gives intermodulation products of the two drive frequencies near the cantilever resonance, where they are measured with high signal to noise ratio. Analysis of this intermodulation response allows for quantitative reconstruction of the contact potential difference. We derive the theory of the method, validate it with numerical simulation and a control experiment, and we demonstrate its utility for fast imaging of the surface photo-voltage on an organic photo-voltaic material.

  20. High voltage insulation of bushing for HTS power equipment

    NASA Astrophysics Data System (ADS)

    Kim, Woo-Jin; Choi, Jae-Hyeong; Kim, Sang-Hyun

    2012-12-01

    For the operation of high temperature superconducting (HTS) power equipments, it is necessary to develop insulating materials and high voltage (HV) insulation technology at cryogenic temperature of bushing. Liquid nitrogen (LN2) is an attractive dielectric liquid. Also, the polymer insulating materials are expected to be used as solid materials such as glass fiber reinforced plastic (GFRP), polytetra-fluoroethylene (PTFE, Teflon), Silicon (Si) rubber, aromatic polyamide (Nomex), EPDM/Silicon alloy compound (EPDM/Si). In this paper, the surface flashover characteristics of various insulating materials in LN2 are studied. These results are studied at both AC and impulse voltage under a non-uniform field. The use of GFRP and Teflon as insulation body for HTS bushing should be much desirable. Especially, GFRP is excellent material not only surface flashover characteristics but also mechanical characteristics at cryogenic temperature. The surface flashover is most serious problem for the shed design in LN2 and operation of superconducting equipments.

  1. Tomato ACS4 is necessary for timely start of and progression through the climacteric phase of fruit ripening

    PubMed Central

    Hoogstrate, Suzanne W.; van Bussel, Lambertus J. A.; Cristescu, Simona M.; Cator, Eric; Mariani, Celestina; Vriezen, Wim H.; Rieu, Ivo

    2014-01-01

    Climacteric fruit ripening, as it occurs in many fruit crops, depends on a rapid, autocatalytic increase in ethylene production. This agriculturally important process has been studied extensively, with tomato simultaneously acting both as a model species and target crop for modification. In tomato, the ethylene biosynthetic genes ACC SYNTHASE2 (ACS2) and ACS4 are highly expressed during fruit ripening, with a combined loss of both ACS2 and ACS4 activity preventing generation of the ethylene burst necessary for fruit ripening. However, the individual roles and importance of ACS2 and ACS4 have not been determined. In this study, we examined specifically the role of ACS4 by comparing the phenotype of an acs4 mutant firstly with that of the wild-type, and secondly with two novel ripening-inhibitor (rin) mutants. Ethylene production during ripening was significantly reduced in both acs4-1, and rin lines, with rin genotypes showing the weaker ethylene burst. Also i) the time between anthesis and the start of fruit ripening and ii) the time required to progress through ripening were significantly longer in acs4-1 than in the wild type, but shorter than in the strongest rin mutant. The delay in ripening was reflected in the lower expression of ripening-related transcripts during the mature green and light red ripening stages. Furthermore, expression of ACS2 and ACS4 was strongly dependent on a functional RIN gene, while ACS2 expression was largely independent of ACS4. Altogether, we show that ACS4 is necessary for normal progression of tomato fruit ripening and that mutation of this gene may provide a useful means for altering ripening traits. PMID:25278945

  2. Screening Fluorescent Voltage Indicators with Spontaneously Spiking HEK Cells

    PubMed Central

    Venkatachalam, Veena; Kralj, Joel M.; Dib-Hajj, Sulayman D.; Waxman, Stephen G.; Cohen, Adam E.

    2013-01-01

    Development of improved fluorescent voltage indicators is a key challenge in neuroscience, but progress has been hampered by the low throughput of patch-clamp characterization. We introduce a line of non-fluorescent HEK cells that stably express NaV 1.3 and KIR 2.1 and generate spontaneous electrical action potentials. These cells enable rapid, electrode-free screening of speed and sensitivity of voltage sensitive dyes or fluorescent proteins on a standard fluorescence microscope. We screened a small library of mutants of archaerhodopsin 3 (Arch) in spiking HEK cells and identified two mutants with greater voltage-sensitivity than found in previously published Arch voltage indicators. PMID:24391999

  3. ACS Expands Role In High School Chemistry.

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1979

    1979-01-01

    Describes some of the services and programs of special interests to high school chemistry teachers that are being provided by ACS, and meant to make ACS membership more attractive to the teachers. (GA)

  4. Electric field in an AC dielectric barrier discharge overlapped with a nanosecond pulse discharge

    NASA Astrophysics Data System (ADS)

    Goldberg, Benjamin M.; Shkurenkov, Ivan; Adamovich, Igor V.; Lempert, Walter R.

    2016-08-01

    The effect of ns discharge pulses on the AC barrier discharge in hydrogen in plane-to-plane geometry is studied using time-resolved measurements of the electric field in the plasma. The AC discharge was operated at a pressure of 300 Torr at frequencies of 500 and 1750 Hz, with ns pulses generated when the AC voltage was near zero. The electric field vector is measured by ps four-wave mixing technique, which generates coherent IR signal proportional to the square of electric field. Absolute calibration was done using an electrostatic (sub-breakdown) field applied to the discharge electrodes, when no plasma was generated. The results are compared with one-dimensional kinetic modeling of the AC discharge and the nanosecond pulse discharge, predicting behavior of both individual micro-discharges and their cumulative effect on the electric field distribution in the electrode gap, using stochastic averaging based on the experimental micro-discharge temporal probability distribution during the AC period. Time evolution of the electric field in the AC discharge without ns pulses, controlled by a superposition of random micro-discharges, exhibits a nearly ‘flat top’ distribution with the maximum near breakdown threshold, reproduced quite well by kinetic modeling. Adding ns pulse discharges on top of the AC voltage waveform changes the AC discharge behavior in a dramatic way, inducing transition from random micro-discharges to a more regular, near-1D discharge. In this case, reproducible volumetric AC breakdown is produced at a well-defined moment after each ns pulse discharge. During the reproducible AC breakdown, the electric field in the plasma exhibits a sudden drop, which coincides in time with a well-defined current pulse. This trend is also predicted by the kinetic model. Analysis of kinetic modeling predictions shows that this effect is caused by large-volume ionization and neutralization of surface charges on the dielectrics by ns discharge pulses. The present

  5. Study of a High Voltage Ion Engine Power Supply

    NASA Technical Reports Server (NTRS)

    Stuart, Thomas A.; King, Roger J.; Mayer, Eric

    1996-01-01

    A complete laboratory breadboard version of a ion engine power converter was built and tested. This prototype operated on a line voltage of 80-120 Vdc, and provided output ratings of 1100 V at 1.8 kW, and 250 V at 20 mA. The high-voltage (HV) output voltage rating was revised from the original value of 1350 V at the beginning of the project. The LV output was designed to hold up during a 1-A surge current lasting up to 1 second. The prototype power converter included a internal housekeeping power supply which also operated from the line input. The power consumed in housekeeping was included in the overall energy budget presented for the ion engine converter. HV and LV output voltage setpoints were commanded through potentiometers. The HV converter itself reached its highest power efficiency of slightly over 93% at low line and maximum output. This would dip below 90% at high line. The no-load (rated output voltages, zero load current) power consumption of the entire system was less than 13 W. A careful loss breakdown shows that converter losses are predominately Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET) conduction losses and HV rectifier snubbing losses, with the rectifier snubbing losses becoming predominant at high line. This suggests that further improvements in power efficiency could best be obtained by either developing a rectifier that was adequately protected against voltage overshoot with less snubbing, or by developing a pre-regulator to reduced the range of line voltage on the converter. The transient testing showed the converter to be fully protected against load faults, including a direct short-circuit from the HV output to the LV output terminals. Two currents sensors were used: one to directly detect any core ratcheting on the output transformer and re-initiate a soft start, and the other to directly detect a load fault and quickly shut down the converter for load protection. The finished converter has been extensively fault tested

  6. Alternative Ac/Ds transposition induces major chromosomal rearrangements in maize.

    PubMed

    Zhang, Jianbo; Yu, Chuanhe; Pulletikurti, Vinay; Lamb, Jonathan; Danilova, Tatiana; Weber, David F; Birchler, James; Peterson, Thomas

    2009-03-15

    Barbara McClintock reported that the Ac/Ds transposable element system can generate major chromosomal rearrangements (MCRs), but the underlying mechanism has not been determined. Here, we identified a series of chromosome rearrangements derived from maize lines containing pairs of closely linked Ac transposable element termini. Molecular and cytogenetic analyses showed that the MCRs in these lines comprised 17 reciprocal translocations and two large inversions. The breakpoints of all 19 MCRs are delineated by Ac termini and characteristic 8-base-pair target site duplications, indicating that the MCRs were generated by precise transposition reactions involving the Ac termini of two closely linked elements. This alternative transposition mechanism may have contributed to chromosome evolution and may also occur during V(D)J recombination resulting in oncogenic translocations. PMID:19299561

  7. Alternative Ac/Ds transposition induces major chromosomal rearrangements in maize.

    PubMed

    Zhang, Jianbo; Yu, Chuanhe; Pulletikurti, Vinay; Lamb, Jonathan; Danilova, Tatiana; Weber, David F; Birchler, James; Peterson, Thomas

    2009-03-15

    Barbara McClintock reported that the Ac/Ds transposable element system can generate major chromosomal rearrangements (MCRs), but the underlying mechanism has not been determined. Here, we identified a series of chromosome rearrangements derived from maize lines containing pairs of closely linked Ac transposable element termini. Molecular and cytogenetic analyses showed that the MCRs in these lines comprised 17 reciprocal translocations and two large inversions. The breakpoints of all 19 MCRs are delineated by Ac termini and characteristic 8-base-pair target site duplications, indicating that the MCRs were generated by precise transposition reactions involving the Ac termini of two closely linked elements. This alternative transposition mechanism may have contributed to chromosome evolution and may also occur during V(D)J recombination resulting in oncogenic translocations.

  8. dc-to-ac power converter for fuel cell system

    SciTech Connect

    Kawabata, T.; Asaeda, T.; Hamasaki, Y.; Yutani, T.

    1983-10-01

    As the interface between fuel cells and the utility line, a self-commutated inverter is preferred to a line-commutated inverter because of its easy controllability. Using the gate turn off (GTO) thyristors, this inverter can have high efficiency and simple circuit configurations. This paper describes the design features and test results of the dc-to-ac power converter, which is principally composed of four-phase transistor chopper and 12-pulse GTO inverter, for a 50kW experimental fuel cell power system. Furthermore, new GTO inverter which improves the circuit efficiency is presented. Special emphasis is placed on a detailed analysis and evaluation of this GTO inverter.

  9. Equivalent circuit modeling of a piezo-patch energy harvester on a thin plate with AC-DC conversion

    NASA Astrophysics Data System (ADS)

    Bayik, B.; Aghakhani, A.; Basdogan, I.; Erturk, A.

    2016-05-01

    As an alternative to beam-like structures, piezoelectric patch-based energy harvesters attached to thin plates can be readily integrated to plate-like structures in automotive, marine, and aerospace applications, in order to directly exploit structural vibration modes of the host system without mass loading and volumetric occupancy of cantilever attachments. In this paper, a multi-mode equivalent circuit model of a piezo-patch energy harvester integrated to a thin plate is developed and coupled with a standard AC-DC conversion circuit. Equivalent circuit parameters are obtained in two different ways: (1) from the modal analysis solution of a distributed-parameter analytical model and (2) from the finite-element numerical model of the harvester by accounting for two-way coupling. After the analytical modeling effort, multi-mode equivalent circuit representation of the harvester is obtained via electronic circuit simulation software SPICE. Using the SPICE software, electromechanical response of the piezoelectric energy harvester connected to linear and nonlinear circuit elements are computed. Simulation results are validated for the standard AC-AC and AC-DC configurations. For the AC input-AC output problem, voltage frequency response functions are calculated for various resistive loads, and they show excellent agreement with modal analysis-based analytical closed-form solution and with the finite-element model. For the standard ideal AC input-DC output case, a full-wave rectifier and a smoothing capacitor are added to the harvester circuit for conversion of the AC voltage to a stable DC voltage, which is also validated against an existing solution by treating the single-mode plate dynamics as a single-degree-of-freedom system.

  10. Improved Programmable High-Voltage Power Supply

    NASA Technical Reports Server (NTRS)

    Castell, Karen; Rutberg, Arthur

    1994-01-01

    Improved dc-to-dc converter functions as programmable high-voltage power supply with low-power-dissipation voltage regulator on high-voltage side. Design of power supply overcomes deficiencies of older designs. Voltage regulation with low power dissipation provided on high-voltage side.

  11. Low voltage nonprimary explosive detonator

    DOEpatents

    Dinegar, Robert H.; Kirkham, John

    1982-01-01

    A low voltage, electrically actuated, nonprimary explosive detonator is disclosed wherein said detonation is achieved by means of an explosive train in which a deflagration-to-detonation transition is made to occur. The explosive train is confined within a cylindrical body and positioned adjacent to low voltage ignition means have electrical leads extending outwardly from the cylindrical confining body. Application of a low voltage current to the electrical leads ignites a self-sustained deflagration in a donor portion of the explosive train which then is made to undergo a transition to detonation further down the train.

  12. Voltage Sensors Monitor Harmful Static

    NASA Technical Reports Server (NTRS)

    2009-01-01

    A tiny sensor, small enough to be worn on clothing, now monitors voltage changes near sensitive instruments after being created to alert Agency workers to dangerous static buildup near fuel operations and avionics. San Diego s Quasar Federal Systems received a Small Business Innovation Research (SBIR) contract from Kennedy Space Center to develop its remote voltage sensor (RVS), a dime-sized electrometer designed to measure triboelectric changes in the environment. One of the unique qualities of the RVS is that it can detect static at greater distances than previous devices, measuring voltage changes from a few centimeters to a few meters away, due to its much-improved sensitivity.

  13. Simultaneous distribution of AC and DC power

    DOEpatents

    Polese, Luigi Gentile

    2015-09-15

    A system and method for the transport and distribution of both AC (alternating current) power and DC (direct current) power over wiring infrastructure normally used for distributing AC power only, for example, residential and/or commercial buildings' electrical wires is disclosed and taught. The system and method permits the combining of AC and DC power sources and the simultaneous distribution of the resulting power over the same wiring. At the utilization site a complementary device permits the separation of the DC power from the AC power and their reconstruction, for use in conventional AC-only and DC-only devices.

  14. Note: Complementary metal-oxide-semiconductor high voltage pulse generation circuits.

    PubMed

    Sun, Jiwei; Wang, Pingshan

    2013-10-01

    We present two types of on-chip pulse generation circuits. The first is based on CMOS pulse-forming-lines (PFLs). It includes a four-stage charge pump, a four-stacked-MOSFET switch and a 5 mm long PFL. The circuit is implemented in a 0.13 μm CMOS process. Pulses of ~1.8 V amplitude with ~135 ps duration on a 50 Ω load are obtained. The obtained voltage is higher than 1.6 V, the rated operating voltage of the process. The second is a high-voltage Marx generator which also uses stacked MOSFETs as high voltage switches. The output voltage is 11.68 V, which is higher than the highest breakdown voltage (~10 V) of the CMOS process. These results significantly extend high-voltage pulse generation capabilities of CMOS technologies.

  15. Electric currents and voltage drops along auroral field lines

    NASA Technical Reports Server (NTRS)

    Stern, D. P.

    1983-01-01

    An assessment is presented of the current state of knowledge concerning Birkeland currents and the parallel electric field, with discussions focusing on the Birkeland primary region 1 sheets, the region 2 sheets which parallel them and appear to close in the partial ring current, the cusp currents (which may be correlated with the interplanetary B(y) component), and the Harang filament. The energy required by the parallel electric field and the associated particle acceleration processes appears to be derived from the Birkeland currents, for which evidence is adduced from particles, inverted V spectra, rising ion beams and expanded loss cones. Conics may on the other hand signify acceleration by electrostatic ion cyclotron waves associated with beams accelerated by the parallel electric field.

  16. Dual design resistor for high voltage conditioning and transmission lines

    DOEpatents

    Siggins, Timothy Lynn; Murray, Charles W.; Walker, Richard L.

    2007-01-23

    A dual resistor for eliminating the requirement for two different value resistors. The dual resistor includes a conditioning resistor at a high resistance value and a run resistor at a low resistance value. The run resistor can travel inside the conditioning resistor. The run resistor is capable of being advanced by a drive assembly until an electrical path is completed through the run resistor thereby shorting out the conditioning resistor and allowing the lower resistance run resistor to take over as the current carrier.

  17. Citizens protest high power lines

    SciTech Connect

    Ray, J.

    1980-04-01

    Survey report:Following an extensive public hearing in New York State concerning the health effects and safety of high voltage power lines, negotiations to establish a research program on the biological effects of the power lines' 60 Hz electric and magnetic fields have been concluded. The aim will be to determine the potential health risks to people who live and work along high voltage rights-of-way. The $5,000,000 program will be designed and administered by three New York State agencies: the Public Service Commission, the Dept. of Health, and the Power Authority. (3 photos)

  18. Low Voltage Electrowetting on Ferroelectric PVDF-HFP Insulator with Highly Tunable Contact Angle Range.

    PubMed

    Sawane, Yogesh B; Ogale, Satishchandra B; Banpurkar, Arun G

    2016-09-14

    We demonstrate a consistent electrowetting response on ferroelectric poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) insulator covered with a thin Teflon AF layer. This bilayer exhibits a factor of 3 enhancement in the contact angle modulation compared to that of conventional single-layered Teflon AF dielectric. On the basis of the proposed model the enhancement is attributed to the high value of effective dielectric constant (εeff ≈ 6) of the bilayer. Furthermore, the bilayer dielectric exhibits a hysteresis-free contact angle modulation over many AC voltage cycles. But the contact angle modulation for DC voltage shows a hysteresis because of the field-induced residual polarization in the ferroelectric layer. Finally, we show that a thin bilayer exhibits contact angle modulation of Δθ (U) ≈ 60° at merely 15 V amplitude of AC voltage indicating a potential dielectric for practical low voltage electrowetting applications. A proof of concept confirms electrowetting based rapid mixing of a fluorescent dye in aqueous glycerol solution for 15 V AC signal.

  19. Low Voltage Electrowetting on Ferroelectric PVDF-HFP Insulator with Highly Tunable Contact Angle Range.

    PubMed

    Sawane, Yogesh B; Ogale, Satishchandra B; Banpurkar, Arun G

    2016-09-14

    We demonstrate a consistent electrowetting response on ferroelectric poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) insulator covered with a thin Teflon AF layer. This bilayer exhibits a factor of 3 enhancement in the contact angle modulation compared to that of conventional single-layered Teflon AF dielectric. On the basis of the proposed model the enhancement is attributed to the high value of effective dielectric constant (εeff ≈ 6) of the bilayer. Furthermore, the bilayer dielectric exhibits a hysteresis-free contact angle modulation over many AC voltage cycles. But the contact angle modulation for DC voltage shows a hysteresis because of the field-induced residual polarization in the ferroelectric layer. Finally, we show that a thin bilayer exhibits contact angle modulation of Δθ (U) ≈ 60° at merely 15 V amplitude of AC voltage indicating a potential dielectric for practical low voltage electrowetting applications. A proof of concept confirms electrowetting based rapid mixing of a fluorescent dye in aqueous glycerol solution for 15 V AC signal. PMID:27553685

  20. An ac quantum voltmeter based on a 10 V programmable Josephson array

    NASA Astrophysics Data System (ADS)

    Lee, Jinni; Behr, Ralf; Palafox, Luis; Katkov, Alexander; Schubert, Marco; Starkloff, Michael; Böck, Andreas Charles

    2013-12-01

    An ac quantum voltmeter based on a 10 V programmable Josephson array that is simple to use, provides dc and ac calibration up to kHz range for equipment widely used in metrology, and ensures direct traceability to a quantum-based standard, is developed. This ac quantum voltmeter is proven to match conventional Josephson standard systems at dc and extends its advantages up to 10 kHz in the low-frequency ac range. The ac quantum voltmeter is capable of performing calibrations up to 7 VRMS in the frequency range from dc to 10 kHz completely under software control. A direct comparison at dc has demonstrated an uncertainty better than 2 parts in 1010 (k = 2). The uncertainty at 1 kHz is better than 1.7 µV V-1 (k = 2) for a measurement time of 1 min. The ac quantum voltmeter is a robust and practical system that fulfils the needs of general metrology laboratories for quantum-based voltage calibrations.