Science.gov

Sample records for 3-phase voltage source

  1. 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…

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. An Inexpensive Source of High Voltage

    ERIC Educational Resources Information Center

    Saraiva, Carlos

    2012-01-01

    As a physics teacher I like recycling old apparatus and using them for demonstrations in my classes. In physics laboratories in schools, sources of high voltage include induction coils or electronic systems that can be bought from companies that sell lab equipment. But these sources can be very expensive. In this article, I will explain how you…

  8. An Inexpensive Source of High Voltage

    NASA Astrophysics Data System (ADS)

    Saraiva, Carlos

    2012-04-01

    As a physics teacher I like recycling old apparatus and using them for demonstrations in my classes.1-4 In physics laboratories in schools, sources of high voltage include induction coils or electronic systems that can be bought from companies that sell lab equipment. But these sources can be very expensive. In this article, I will explain how you can use a car ignition coil as a high voltage source. Such a coil can be obtained from an old car found in a car salvage yard and used to power cathode ray tubes and discharge tubes to observe the spectra. It can also be used as a source of ignition to simulate explosive combustion that occurs in car engines, rockets, etc. You can also buy these coils in shops that sell car accessories and they are cheaper than induction coils. In Fig. 1 you can see a coil that I used.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. A multilevel voltage-source converter system with balanced dc voltages

    SciTech Connect

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

    1995-04-01

    A multilevel voltage-source converter system is proposed for high-voltage, high-power applications such as large induction motor drives, back-to-back interconnected power systems, and electrical traction drives. Multilevel voltage-source converters have a voltage unbalance problem in the dc capacitors. The problem may be solved by use of additional voltage regulators or separate dc sources. However, these solutions are found not to be practicable for most applications. The proposed converter system can solve the voltage unbalance problem of the conventional multilevel voltage-source converters, without using any additional voltage balance circuits or separate voltage sources. Mechanism of the voltage unbalance problem is analyzed theoretically in this paper. The validity of the new converter system is demonstrated by simulation and experiment.

  14. Note: Galvanic isolated voltage source using a single photodiode.

    PubMed

    Stoican, O S

    2010-04-01

    A galvanic isolated voltage source able to provide several volts by using a single photodiode is described. A pulse-modulated laser beam is sent to a photodiode. By using a step-up transformer the amplitude of the variable voltage generated by the photodiode is increased. Adding a rectifier cell the variable voltage is converted back into a dc voltage.

  15. ENSYSTROB - Design, manufacturing and test of a 3-phase resistive fault current limiter based on coated conductors for medium voltage application

    NASA Astrophysics Data System (ADS)

    Elschner, S.; Kudymow, A.; Brand, J.; Fink, S.; Goldacker, W.; Grilli, F.; Noe, M.; Vojenciak, M.; Hobl, A.; Bludau, M.; Jänke, C.; Krämer, S.; Bock, J.

    2012-11-01

    Within the German project ENSYSTROB a 3-phase resistive fault current limiter for medium voltage applications (12 kV, 533 Arms) was designed, built, tested and installed in the grid for a one year’s field test. The superconducting modules are made of YBCO coated conductors and replace the modules of an already successfully tested limiter on the basis of BSCCO 2212 bulk material. The components are multifilar spirals equipped with pairs of 12 mm wide YBCO tapes. The single components were characterized with respect to critical current, AC losses and limitation behavior under all possible operation conditions. The finally mounted limiter was successfully tested with respect to high voltage and limitation according to the standards of the customer. It is now installed and operating in its field test location. Finally we give a first comparison of both materials with respect to the different operational aspects.

  16. Stable voltage source for Penning trap experiments.

    PubMed

    Pinegar, David B; Blaum, Klaus; Biesiadzinski, Tomasz P; Zafonte, Steven L; Van Dyck, Robert S

    2009-06-01

    A voltage reference has been developed to bias ring electrodes of two Penning traps between -90 and 0 V. For output voltages near -90 V, the Allan deviation of the system's voltage instability is less than 1 part in 10(8) over all time scales shorter than 10(4) s. For averaging times longer than several seconds, the system's stability is determined almost completely by the noise, drift, and aging of the zener diodes in the array of voltage reference integrated circuits. For shorter averaging times, active filters built into the new system significantly reduce the intrinsic noise of the zener diodes. The system makes it possible to continuously adjust the ring voltages for frequency locking the axial motion in the two Penning traps. By keeping electrical noise highly correlated between the two traps, measurement uncertainty should be reduced for precision experiments such as Penning trap mass spectrometry.

  17. LOW VOLTAGE 14 Mev NEUTRON SOURCE

    DOEpatents

    Little, R.N. Jr.; Graves, E.R.

    1959-09-29

    An apparatus yielding high-energy neutrons at the rate of 10/sup 8/ or more per second by the D,T or D,D reactions is described. The deuterium gas filling is ionized by electrons emitted from a filament, and the resulting ions are focused into a beam and accelerated against a fixed target. The apparatus is built in accordance with the relationship V/sub s/ = A--B log pd, where V/sub s/ is the sparking voltage, p the gas pressure, and d the gap length between the high voltage electrodes. Typical parameters to obtain the high neutron yields are 55 to 80 kv, 0.5 to 7.0 ma beam current, 5 to 12 microns D/sub 2/, and a gap length of 1 centimeter.

  18. Superconducting, fast rise-time voltage source

    SciTech Connect

    Lumley, R.M.

    1983-01-25

    A pulse generator comprises a toroid of a superconducting material such as niobium on a glass or ceramic substrate. A cryogenic source such as liquid helium cools the toroid to within a few degrees of absolute zero and a perpetually circulatory current is set up in the toroid. A laser beam is fired at the toroid to cause localized heating and the resultant current drop due to the material resistance causes an output pulse to be induced in an adjacent current winding.

  19. 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.

  20. 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.

  1. A virtual source model for Kilo-voltage cone beam CT: Source characteristics and model validation

    SciTech Connect

    Spezi, E.; Volken, W.; Frei, D.; Fix, M. K.

    2011-09-15

    Purpose: The purpose of this investigation was to study the source characteristics of a clinical kilo-voltage cone beam CT unit and to develop and validate a virtual source model that could be used for treatment planning purposes. Methods: We used a previously commissioned full Monte Carlo model and new bespoke software to study the source characteristics of a clinical kilo-voltage cone beam CT (CBCT) unit. We identified the main particle sources, their spatial, energy and angular distribution for all the image acquisition presets currently used in our clinical practice. This includes a combination of two energies (100 and 120 kVp), two filters (neutral and bowtie), and eight different x-ray beam apertures. We subsequently built a virtual source model which we validated against full Monte Carlo calculations. Results: We found that the radiation output of the clinical kilo-voltage cone beam CT unit investigated in this study could be reproduced with a virtual model comprising of two sources (target and filtration cone) or three sources (target, filtration cone and bowtie filter) when additional filtration was used. With this model, we accounted for more than 97% of the photons exiting the unit. Each source in our model was characterised by a origin distribution in both X and Y directions, a fluence map, a single energy spectrum for unfiltered beams and a two dimensional energy spectrum for bowtie filtered beams. The percentage dose difference between full Monte Carlo and virtual source model based dose distributions was well within the statistical uncertainty associated with the calculations ( {+-} 2%, one standard deviation) in all cases studied. Conclusions: The virtual source that we developed is accurate in calculating the dose delivered from a commercial kilo-voltage cone beam CT unit operating with routine clinical image acquisition settings. Our data have also shown that target, filtration cone, and bowtie filter sources needed to be all included in the model

  2. Voltage regulator for battery power source. [using a bipolar transistor

    NASA Technical Reports Server (NTRS)

    Black, J. M. (Inventor)

    1979-01-01

    A bipolar transistor in series with the battery as the control element also in series with a zener diode and a resistor is used to maintain a predetermined voltage until the battery voltage decays to very nearly the predetermined voltage. A field effect transistor between the base of the bipolar transistor and a junction between the zener diode and resistor regulates base current of the bipolar transistor, thereby regulating the conductivity of the bipolar transistor for control of the output voltage.

  3. Load insensitive electrical device. [power converters for supplying direct current at one voltage from a source at another voltage

    NASA Technical Reports Server (NTRS)

    Schwarz, F. C. (Inventor)

    1974-01-01

    A class of power converters is described for supplying direct current at one voltage from a source at another voltage. It includes a simple passive circuit arrangement of solid-state switches, inductors, and capacitors by which the output voltage of the converter tends to remain constant in spite of changes in load. The switches are sensitive to the current flowing in the circuit and are employed to permit the charging of capacitance devices in accordance with the load requirements. Because solid-state switches (such as SCR's) may be used with relatively high voltage and because of the inherent efficiency of the invention that permits relatively high switching frequencies, power supplies built in accordance with the invention, together with their associated cabling, can be substantially lighter in weight for a given output power level and efficiency of operation than systems of the prior art.

  4. High voltage holding in the negative ion sources with cesium deposition.

    PubMed

    Belchenko, Yu; Abdrashitov, G; Ivanov, A; Sanin, A; Sotnikov, O

    2016-02-01

    High voltage holding of the large surface-plasma negative ion source with cesium deposition was studied. It was found that heating of ion-optical system electrodes to temperature >100 °C facilitates the source conditioning by high voltage pulses in vacuum and by beam shots. The procedure of electrode conditioning and the data on high-voltage holding in the negative ion source with small cesium seed are described. The mechanism of high voltage holding improvement by depletion of cesium coverage is discussed.

  5. High voltage holding in the negative ion sources with cesium deposition.

    PubMed

    Belchenko, Yu; Abdrashitov, G; Ivanov, A; Sanin, A; Sotnikov, O

    2016-02-01

    High voltage holding of the large surface-plasma negative ion source with cesium deposition was studied. It was found that heating of ion-optical system electrodes to temperature >100 °C facilitates the source conditioning by high voltage pulses in vacuum and by beam shots. The procedure of electrode conditioning and the data on high-voltage holding in the negative ion source with small cesium seed are described. The mechanism of high voltage holding improvement by depletion of cesium coverage is discussed. PMID:26932002

  6. Pulsed voltage electrospray ion source and method for preventing analyte electrolysis

    DOEpatents

    Kertesz, Vilmos; Van Berkel, Gary

    2011-12-27

    An electrospray ion source and method of operation includes the application of pulsed voltage to prevent electrolysis of analytes with a low electrochemical potential. The electrospray ion source can include an emitter, a counter electrode, and a power supply. The emitter can include a liquid conduit, a primary working electrode having a liquid contacting surface, and a spray tip, where the liquid conduit and the working electrode are in liquid communication. The counter electrode can be proximate to, but separated from, the spray tip. The power system can supply voltage to the working electrode in the form of a pulse wave, where the pulse wave oscillates between at least an energized voltage and a relaxation voltage. The relaxation duration of the relaxation voltage can range from 1 millisecond to 35 milliseconds. The pulse duration of the energized voltage can be less than 1 millisecond and the frequency of the pulse wave can range from 30 to 800 Hz.

  7. A prototype of a high-voltage platform for the KRION ion source

    NASA Astrophysics Data System (ADS)

    Alexandrov, V. S.; Donets, E. E.; Konnov, G. I.; Kosukhin, V. V.; Sidorova, V. O.; Sidorov, A. I.; Shvetsov, V. S.; Trubnikov, G. V.

    2014-09-01

    A high-voltage platform that has been developed for the KRION ion source is described. The platform design concept is explained. The calculations that have been performed of the influence of the design and materials on the source magnetic field make it possible to define a range of materials suitable for manufacturing the platform. The major components of the high-voltage platform, such as a high-voltage power supplier, and decoupling insulators of the high-voltage power source, and the main and supplementary platforms, are chosen and described. It is determined that, to exclude electric breakdowns and corona discharges, one should use an electrically shielded channel with a cryocooler and power supplies for the KRION-source coupling cables.

  8. An ultra-stable voltage source for precision Penning-trap experiments

    NASA Astrophysics Data System (ADS)

    Böhm, Ch.; Sturm, S.; Rischka, A.; Dörr, A.; Eliseev, S.; Goncharov, M.; Höcker, M.; Ketter, J.; Köhler, F.; Marschall, D.; Martin, J.; Obieglo, D.; Repp, J.; Roux, C.; Schüssler, R. X.; Steigleder, M.; Streubel, S.; Wagner, Th.; Westermann, J.; Wieder, V.; Zirpel, R.; Melcher, J.; Blaum, K.

    2016-08-01

    An ultra-stable and low-noise 25-channel voltage source providing 0 to -100 V has been developed. It will supply stable bias potentials for Penning-trap electrodes used in high-precision experiments. The voltage source generates all its supply voltages via a specially designed transformer. Each channel can be operated either in a precision mode or can be dynamically ramped. A reference module provides reference voltages for all the channels, each of which includes a low-noise amplifier to gain a factor of 10 in the output stage. A relative voltage stability of δV / V ≈ 2 ×10-8 has been demonstrated at -89 V within about 10 min.

  9. Analysis of Paralleling Limited Capacity Voltage Sources by Projective Geometry Method

    PubMed Central

    2014-01-01

    The droop current-sharing method for voltage sources of a limited capacity is considered. Influence of equalizing resistors and load resistor is investigated on uniform distribution of relative values of currents when the actual loading corresponds to the capacity of a concrete source. Novel concepts for quantitative representation of operating regimes of sources are entered with use of projective geometry method. PMID:24683335

  10. Source of stray voltage and effect on cow health and performance

    SciTech Connect

    Appleman, R.D.; Gustafson, R.J.

    1985-01-01

    In dairy cows, two distinct and important aspects of the interrelationship between stray voltage problems on the farm and dairy cow productivity can be identified. One is behavioral modification that increases in intensity when currents associated with neutral-to-earth voltages above .7 V find a pathway through the cow. The other is immediate endocrine response. Results of research are less clear on the current necessary for the latter to occur; it may require 8 mA or more. This implies, depending on the pathway and the cow's pathway resistance, that voltage difference between two cow contact points must exceed 3 V. Resistance of different cow pathways range from 350 to 1700 OMEGA. Milk production is more likely to be affected adversely when cows are subjected to shock patterns both intermittent and irregular. This paper identifies various sources of stray voltage problems and discusses appropriate procedures for correction.

  11. Demonstration of Johnson noise thermometry with all-superconducting quantum voltage noise source

    NASA Astrophysics Data System (ADS)

    Yamada, Takahiro; Urano, Chiharu; Maezawa, Masaaki

    2016-01-01

    We present a Johnson noise thermometry (JNT) system based on an integrated quantum voltage noise source (IQVNS) that has been fully implemented using superconducting circuit technology. To enable precise measurement of Boltzmann's constant, an IQVNS chip was designed to produce intrinsically calculable pseudo-white noise to calibrate the JNT system. On-chip real-time generation of pseudo-random codes via simple circuits produced pseudo-voltage noise with a harmonic tone interval of less than 1 Hz, which was one order of magnitude finer than the harmonic tone interval of conventional quantum voltage noise sources. We estimated a value for Boltzmann's constant experimentally by performing JNT measurements at the temperature of the triple point of water using the IQVNS chip.

  12. 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.

  13. A zero-voltage switching technique for minimizing the current-source power of implanted stimulators.

    PubMed

    Çilingiroğlu, Uğur; İpek, Sercan

    2013-08-01

    The current-source power of an implanted stimulator is reduced almost to the theoretical minimum by driving the electrodes directly from the secondary port of the inductive link with a dedicated zero-voltage switching power supply. A feedback loop confined to the secondary of the inductive link adjusts the timing and conduction angle of switching to provide just the right amount of supply voltage needed for keeping the current-source voltage constant at or slightly above the compliance limit. Since drive is based on current rather than voltage, and supply-voltage update is near real-time, the quality of the current pulses is high regardless of how the electrode impedance evolves during stimulation. By scaling the switching frequency according to power demand, the technique further improves overall power consumption of the stimulator. The technique is implemented with a very simple control circuitry comprising a comparator, a Schmitt trigger and a logic gate of seven devices in addition to an on-chip switch and an off-chip capacitor. The power consumed by the proposed supply circuit itself is no larger than what the linear regulator of a conventional supply typically consumes for the same stimulation current. Still, the sum of supply and current-source power is typically between 20% and 75% of the conventional source power alone. Functionality of the proposed driver is verified experimentally on a proof-of-concept prototype built with 3.3 V devices in a 0.18 μm CMOS technology. PMID:23893206

  14. Multifunctional voltage source inverter for renewable energy integration and power quality conditioning.

    PubMed

    Dai, NingYi; Lam, Chi-Seng; Zhang, WenChen

    2014-01-01

    In order to utilize the energy from the renewable energy sources, power conversion system is necessary, in which the voltage source inverter (VSI) is usually the last stage for injecting power to the grid. It is an economical solution to add the function of power quality conditioning to the grid-connected VSI in the low-voltage distribution system. Two multifunctional VSIs are studied in this paper, that is, inductive-coupling VSI and capacitive-coupling VSI, which are named after the fundamental frequency impedance of their coupling branch. The operation voltages of the two VSIs are compared when they are used for renewable energy integration and power quality conditioning simultaneously. The operation voltage of the capacitive-coupling VSI can be set much lower than that of the inductive-coupling VSI when reactive power is for compensating inductive loads. Since a large portion of the loads in the distribution system are inductive, the capacitive-coupling VSI is further studied. The design and control method of the multifunctional capacitive-coupling VSI are proposed in this paper. Simulation and experimental results are provided to show its validity.

  15. Multifunctional Voltage Source Inverter for Renewable Energy Integration and Power Quality Conditioning

    PubMed Central

    Dai, NingYi; Lam, Chi-Seng; Zhang, WenChen

    2014-01-01

    In order to utilize the energy from the renewable energy sources, power conversion system is necessary, in which the voltage source inverter (VSI) is usually the last stage for injecting power to the grid. It is an economical solution to add the function of power quality conditioning to the grid-connected VSI in the low-voltage distribution system. Two multifunctional VSIs are studied in this paper, that is, inductive-coupling VSI and capacitive-coupling VSI, which are named after the fundamental frequency impedance of their coupling branch. The operation voltages of the two VSIs are compared when they are used for renewable energy integration and power quality conditioning simultaneously. The operation voltage of the capacitive-coupling VSI can be set much lower than that of the inductive-coupling VSI when reactive power is for compensating inductive loads. Since a large portion of the loads in the distribution system are inductive, the capacitive-coupling VSI is further studied. The design and control method of the multifunctional capacitive-coupling VSI are proposed in this paper. Simulation and experimental results are provided to show its validity. PMID:25177725

  16. Multifunctional voltage source inverter for renewable energy integration and power quality conditioning.

    PubMed

    Dai, NingYi; Lam, Chi-Seng; Zhang, WenChen

    2014-01-01

    In order to utilize the energy from the renewable energy sources, power conversion system is necessary, in which the voltage source inverter (VSI) is usually the last stage for injecting power to the grid. It is an economical solution to add the function of power quality conditioning to the grid-connected VSI in the low-voltage distribution system. Two multifunctional VSIs are studied in this paper, that is, inductive-coupling VSI and capacitive-coupling VSI, which are named after the fundamental frequency impedance of their coupling branch. The operation voltages of the two VSIs are compared when they are used for renewable energy integration and power quality conditioning simultaneously. The operation voltage of the capacitive-coupling VSI can be set much lower than that of the inductive-coupling VSI when reactive power is for compensating inductive loads. Since a large portion of the loads in the distribution system are inductive, the capacitive-coupling VSI is further studied. The design and control method of the multifunctional capacitive-coupling VSI are proposed in this paper. Simulation and experimental results are provided to show its validity. PMID:25177725

  17. Current Tracking Control of Voltage Source PWM Inverters Using Adaptive Digital Signal Processing

    NASA Astrophysics Data System (ADS)

    Fukuda, Shoji; Furukawa, Yuya

    An active filter (AF) is required to have a high control capability of tracking a time-varying current reference. However, a steady-state current error always exists if a conventional proportional and integral (PI) regulator is used because the current reference varies in time. This paper proposes the application of adaptive digital signal processing (ADSP) to the current control of voltage source PWM inverters. ADSP does not require any additional hardware. It can automatically minimize the mean square-error. Since the processing time available by a computer is limited, ADSP cannot eliminate higher order harmonics but can eliminate lower order harmonics such as 5th to 17th. Experimental results demonstrate that ADSP is useful for improving the reference tracking performance of voltage source inverters.

  18. Improved PHIP polarization using a precision, low noise, voltage controlled current source.

    PubMed

    Agraz, Jose; Grunfeld, Alexander; Cunningham, Karl; Li, Debiao; Wagner, Shawn

    2013-10-01

    Existing para-hydrogen induced polarization (PHIP) instrumentation relies on magnetic fields to hyperpolarize substances. These hyperpolarized substances have enhanced magnetic resonance imaging (MRI) signals over 10,000 fold, allowing for MRI at the molecular level. Required magnetic fields are generated by energizing a solenoid coil with current produced by a voltage controlled voltage source (VCVS), also known as a power supply. A VCVS lacks the current regulation necessary to keep magnetic field fluctuations to a minimum, which results in low PHIP polarization. A voltage controlled current source (VCCS) is an electric circuit that generates a steady flow of electrons proportional to an input voltage. A low noise VCCS provides the solenoid current flow regulation necessary to generate a stable static magnetic field (Bo). We discuss the design and implementation of a low noise, high stability, VCCS for magnetic field generation with minimum variations. We show that a precision, low noise, voltage reference driving a metal oxide semiconductor field effect transistor (MOSFET) based current sink, results in the current flow control necessary for generating a low noise and high stability Bo. In addition, this work: (1) compares current stability for ideal VCVS and VCCS models using transfer functions (TF), (2) develops our VCCS design's TF, (3) measures our VCCS design's thermal & 1/f noise, and (4) measures and compares hydroxyethyl-propionate (HEP) polarization obtained using a VCVS and our VCCS. The hyperpolarization of HEP was done using a PHIP instrument developed in our lab. Using our VCCS design, HEP polarization magnitude data show a statistically significant increase in polarization over using a VCVS. Circuit schematic, bill of materials, board layout, TF derivation, and Matlab simulations code are included as supplemental files.

  19. Improved PHIP polarization using a precision, low noise, voltage controlled current source

    NASA Astrophysics Data System (ADS)

    Agraz, Jose; Grunfeld, Alexander; Cunningham, Karl; Li, Debiao; Wagner, Shawn

    2013-10-01

    Existing para-hydrogen induced polarization (PHIP) instrumentation relies on magnetic fields to hyperpolarize substances. These hyperpolarized substances have enhanced magnetic resonance imaging (MRI) signals over 10,000 fold, allowing for MRI at the molecular level. Required magnetic fields are generated by energizing a solenoid coil with current produced by a voltage controlled voltage source (VCVS), also known as a power supply. A VCVS lacks the current regulation necessary to keep magnetic field fluctuations to a minimum, which results in low PHIP polarization. A voltage controlled current source (VCCS) is an electric circuit that generates a steady flow of electrons proportional to an input voltage. A low noise VCCS provides the solenoid current flow regulation necessary to generate a stable static magnetic field (Bo). We discuss the design and implementation of a low noise, high stability, VCCS for magnetic field generation with minimum variations. We show that a precision, low noise, voltage reference driving a metal oxide semiconductor field effect transistor (MOSFET) based current sink, results in the current flow control necessary for generating a low noise and high stability Bo. In addition, this work: (1) compares current stability for ideal VCVS and VCCS models using transfer functions (TF), (2) develops our VCCS design's TF, (3) measures our VCCS design's thermal & 1/f noise, and (4) measures and compares hydroxyethyl-propionate (HEP) polarization obtained using a VCVS and our VCCS. The hyperpolarization of HEP was done using a PHIP instrument developed in our lab. Using our VCCS design, HEP polarization magnitude data show a statistically significant increase in polarization over using a VCVS. Circuit schematic, bill of materials, board layout, TF derivation, and Matlab simulations code are included as supplemental files.

  20. Improved PHIP polarization using a precision, low noise, voltage controlled current source.

    PubMed

    Agraz, Jose; Grunfeld, Alexander; Cunningham, Karl; Li, Debiao; Wagner, Shawn

    2013-10-01

    Existing para-hydrogen induced polarization (PHIP) instrumentation relies on magnetic fields to hyperpolarize substances. These hyperpolarized substances have enhanced magnetic resonance imaging (MRI) signals over 10,000 fold, allowing for MRI at the molecular level. Required magnetic fields are generated by energizing a solenoid coil with current produced by a voltage controlled voltage source (VCVS), also known as a power supply. A VCVS lacks the current regulation necessary to keep magnetic field fluctuations to a minimum, which results in low PHIP polarization. A voltage controlled current source (VCCS) is an electric circuit that generates a steady flow of electrons proportional to an input voltage. A low noise VCCS provides the solenoid current flow regulation necessary to generate a stable static magnetic field (Bo). We discuss the design and implementation of a low noise, high stability, VCCS for magnetic field generation with minimum variations. We show that a precision, low noise, voltage reference driving a metal oxide semiconductor field effect transistor (MOSFET) based current sink, results in the current flow control necessary for generating a low noise and high stability Bo. In addition, this work: (1) compares current stability for ideal VCVS and VCCS models using transfer functions (TF), (2) develops our VCCS design's TF, (3) measures our VCCS design's thermal & 1/f noise, and (4) measures and compares hydroxyethyl-propionate (HEP) polarization obtained using a VCVS and our VCCS. The hyperpolarization of HEP was done using a PHIP instrument developed in our lab. Using our VCCS design, HEP polarization magnitude data show a statistically significant increase in polarization over using a VCVS. Circuit schematic, bill of materials, board layout, TF derivation, and Matlab simulations code are included as supplemental files. PMID:23988431

  1. 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.

  2. 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

  3. Grid Integration of Single Stage Solar PV System using Three-level Voltage Source Converter

    NASA Astrophysics Data System (ADS)

    Hussain, Ikhlaq; Kandpal, Maulik; Singh, Bhim

    2016-08-01

    This paper presents a single stage solar PV (photovoltaic) grid integrated power generating system using a three level voltage source converter (VSC) operating at low switching frequency of 900 Hz with robust synchronizing phase locked loop (RS-PLL) based control algorithm. To track the maximum power from solar PV array, an incremental conductance algorithm is used and this maximum power is fed to the grid via three-level VSC. The use of single stage system with three level VSC offers the advantage of low switching losses and the operation at high voltages and high power which results in enhancement of power quality in the proposed system. Simulated results validate the design and control algorithm under steady state and dynamic conditions.

  4. FPGA techniques based new hybrid modulation strategies for voltage source inverters.

    PubMed

    Sudha, L U; Baskaran, J; Elankurisil, S A

    2015-01-01

    This paper corroborates three different hybrid modulation strategies suitable for single-phase voltage source inverter. The proposed method is formulated using fundamental switching and carrier based pulse width modulation methods. The main tale of this proposed method is to optimize a specific performance criterion, such as minimization of the total harmonic distortion (THD), lower order harmonics, switching losses, and heat losses. The proposed method is articulated using fundamental switching and carrier based pulse width modulation methods. Thus, the harmonic pollution in the power system will be reduced and the power quality will be augmented with better harmonic profile for a target fundamental output voltage. The proposed modulation strategies are simulated in MATLAB r2010a and implemented in a Xilinx spartan 3E-500 FG 320 FPGA processor. The feasibility of these modulation strategies is authenticated through simulation and experimental results.

  5. FPGA Techniques Based New Hybrid Modulation Strategies for Voltage Source Inverters

    PubMed Central

    Sudha, L. U.; Baskaran, J.; Elankurisil, S. A.

    2015-01-01

    This paper corroborates three different hybrid modulation strategies suitable for single-phase voltage source inverter. The proposed method is formulated using fundamental switching and carrier based pulse width modulation methods. The main tale of this proposed method is to optimize a specific performance criterion, such as minimization of the total harmonic distortion (THD), lower order harmonics, switching losses, and heat losses. The proposed method is articulated using fundamental switching and carrier based pulse width modulation methods. Thus, the harmonic pollution in the power system will be reduced and the power quality will be augmented with better harmonic profile for a target fundamental output voltage. The proposed modulation strategies are simulated in MATLAB r2010a and implemented in a Xilinx spartan 3E-500 FG 320 FPGA processor. The feasibility of these modulation strategies is authenticated through simulation and experimental results. PMID:25821852

  6. Inductive Voltage Adder Driven X-Ray Sources for Hydrodynamic Radiography

    SciTech Connect

    Bailey, V.; Cordova, S.; Droemer, D.; Gustwiller, J.; Hunt, E.; Johnson, D.L.; MacLeod, G.; Maenchen, John; Menge, P.; Molina, I.; Oliver, B; Olson, C.; Rosenthal, S; Rovang, D.; Smith, I.; Welch, D.; Woo, L.

    1999-06-17

    Inductive Voltage Adder (IVA) accelerators were developed to provide high-current (100s of kA) power pulses at high voltage (up to 20 MV) using robust modular components. This architecture simultaneously resolves problems found in conventional pulsed and linear induction accelerators. A variety of high-brightness pulsed x-ray radiographic sources are needed from sub-megavolt to 16-MeV endpoints with greater source brightness (dose/spot) than presently available. We are applying IVA systems to produce very intense (up to 75 TW/cm{sup 2}) electron beams for these flash radiographic applications. The accelerator electromagnetic pulse is converted to a directed electron beam at the end of a self-magnetically insulated vacuum transmission line. The cantilevered cathode threading the accelerator cavities terminates in a small (1-mm diameter) needle, producing the electron beam which is transported to a grounded bremsstrahlung converter within a strong ({approximately}50-T) axial magnetic field. These systems produce mm-sized stable electron beams, yielding very intense x-ray sources. Detailed simulations of the electron beam generation, transport, and target interaction are presented along with scaling laws for the radiation production and x-ray spot size. Experimental studies confirm these simulations and show this reliable, compact, and inexpensive technology scales to 1000-R doses a meter from a mm-diameter source in 50 ns.

  7. 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.

  8. Sources of resonance-related errors in capacitance versus voltage measurement systems

    NASA Astrophysics Data System (ADS)

    Polishchuk, Igor; Brown, George; Huff, Howard

    2000-10-01

    A frequency dependence of the capacitance of metal-oxide-semiconductor devices is often observed in wafer-level probe station measurements for frequencies exceeding 100 kHz. It is well established, however, that the true capacitance value in the SiO2 devices biased into accumulation should remain frequency-independent well into the gigahertz range. Consequently, the apparent frequency dependence of the capacitance versus voltage characteristic may be the result of a resonance present in the measurement setup. We present a quantitative analysis, which can be used to identify the sources of error, characterize a measurement system, and improve the precision of the collected data.

  9. A very low noise, high accuracy, programmable voltage source for low frequency noise measurements

    NASA Astrophysics Data System (ADS)

    Scandurra, Graziella; Giusi, Gino; Ciofi, Carmine

    2014-04-01

    In this paper an approach for designing a programmable, very low noise, high accuracy voltage source for biasing devices under test in low frequency noise measurements is proposed. The core of the system is a supercapacitor based two pole low pass filter used for filtering out the noise produced by a standard DA converter down to 100 mHz with an attenuation in excess of 40 dB. The high leakage current of the supercapacitors, however, introduces large DC errors that need to be compensated in order to obtain high accuracy as well as very low output noise. To this end, a proper circuit topology has been developed that allows to considerably reduce the effect of the supercapacitor leakage current on the DC response of the system while maintaining a very low level of output noise. With a proper design an output noise as low as the equivalent input voltage noise of the OP27 operational amplifier, used as the output buffer of the system, can be obtained with DC accuracies better that 0.05% up to the maximum output of 8 V. The expected performances of the proposed voltage source have been confirmed both by means of SPICE simulations and by means of measurements on actual prototypes. Turn on and stabilization times for the system are of the order of a few hundred seconds. These times are fully compatible with noise measurements down to 100 mHz, since measurement times of the order of several tens of minutes are required in any case in order to reduce the statistical error in the measured spectra down to an acceptable level.

  10. A very low noise, high accuracy, programmable voltage source for low frequency noise measurements.

    PubMed

    Scandurra, Graziella; Giusi, Gino; Ciofi, Carmine

    2014-04-01

    In this paper an approach for designing a programmable, very low noise, high accuracy voltage source for biasing devices under test in low frequency noise measurements is proposed. The core of the system is a supercapacitor based two pole low pass filter used for filtering out the noise produced by a standard DA converter down to 100 mHz with an attenuation in excess of 40 dB. The high leakage current of the supercapacitors, however, introduces large DC errors that need to be compensated in order to obtain high accuracy as well as very low output noise. To this end, a proper circuit topology has been developed that allows to considerably reduce the effect of the supercapacitor leakage current on the DC response of the system while maintaining a very low level of output noise. With a proper design an output noise as low as the equivalent input voltage noise of the OP27 operational amplifier, used as the output buffer of the system, can be obtained with DC accuracies better that 0.05% up to the maximum output of 8 V. The expected performances of the proposed voltage source have been confirmed both by means of SPICE simulations and by means of measurements on actual prototypes. Turn on and stabilization times for the system are of the order of a few hundred seconds. These times are fully compatible with noise measurements down to 100 mHz, since measurement times of the order of several tens of minutes are required in any case in order to reduce the statistical error in the measured spectra down to an acceptable level. PMID:24784633

  11. Experimental Verification of Application of Looped System and Centralized Voltage Control in a Distribution System with Renewable Energy Sources

    NASA Astrophysics Data System (ADS)

    Hanai, Yuji; Hayashi, Yasuhiro; Matsuki, Junya

    The line voltage control in a distribution network is one of the most important issues for a penetration of Renewable Energy Sources (RES). A loop distribution network configuration is an effective solution to resolve voltage and distribution loss issues concerned about a penetration of RES. In this paper, for a loop distribution network, the authors propose a voltage control method based on tap change control of LRT and active/reactive power control of RES. The tap change control of LRT takes a major role of the proposed voltage control. Additionally the active/reactive power control of RES supports the voltage control when voltage deviation from the upper or lower voltage limit is unavoidable. The proposed method adopts SCADA system based on measured data from IT switches, which are sectionalizing switch with sensor installed in distribution feeder. In order to check the validity of the proposed voltage control method, experimental simulations using a distribution system analog simulator “ANSWER” are carried out. In the simulations, the voltage maintenance capability in the normal and the emergency is evaluated.

  12. Design and Development of High Voltage Direct Current (DC) Sources for the Solar Array Module Plasma Interaction Experiment

    NASA Technical Reports Server (NTRS)

    Bibyk, Irene K.; Wald, Lawrence W.

    1995-01-01

    Two programmable, high voltage DC power supplies were developed as part of the flight electronics for the Solar Array Module Plasma Interaction Experiment (SAMPIE). SAMPIE's primary objectives were to study and characterize the high voltage arcing and parasitic current losses of various solar cells and metal samples within the space plasma of low earth orbit (LEO). High voltage arcing can cause large discontinuous changes in spacecraft potential which lead to damage of the power system materials and significant Electromagnetic Interference (EMI). Parasitic currents cause a change in floating potential which lead to reduced power efficiency. These primary SAMPIE objectives were accomplished by applying artificial biases across test samples over a voltage range from -600 VDC to +300 VDC. This paper chronicles the design, final development, and test of the two programmable high voltage sources for SAMPIE. The technical challenges to the design for these power supplies included vacuum, space plasma effects, thermal protection, Shuttle vibrations and accelerations.

  13. Measuring bi-directional current through a field-effect transistor by virtue of drain-to-source voltage measurement

    DOEpatents

    Turner, Steven Richard

    2006-12-26

    A method and apparatus for measuring current, and particularly bi-directional current, in a field-effect transistor (FET) using drain-to-source voltage measurements. The drain-to-source voltage of the FET is measured and amplified. This signal is then compensated for variations in the temperature of the FET, which affects the impedance of the FET when it is switched on. The output is a signal representative of the direction of the flow of current through the field-effect transistor and the level of the current through the field-effect transistor. Preferably, the measurement only occurs when the FET is switched on.

  14. The Digital Simulation of Synchronous Motors Fed by Voltage-Source Inverters Over Wide Speed and Frequency Ranges

    NASA Astrophysics Data System (ADS)

    Rowihal, Said Soliman

    Both voltage-source and current-source inverters are widely used for supplying three-phase power to induction motor drives, each having their advantages and disadvantages. For high power drives and applications requiring accurate speed and tracking coordination, the synchronous motors are the optimum choice. For constant speed applications of synchronous motor drives, current-source inverters tend to be favored as the motor can usually be operated in the overexcited leading power factor region, thus providing the inverter with sufficient electro-motive force to allow natural commutation. Generally speaking low speed operation of synchronous motors is not satisfactory from naturally commutated current-source inverters. To provide a dynamic range of speed and frequency would require expensive control circuitry and complicates the performance of the drive. The advantage of the voltage-source inverter for the wide range of speed and frequency control herein envisaged is that forced commutation is employed throughout the range and the commutating circuits have been well developed and established. On balance, voltage-source inverters represent a viable compromise for variable-speed three -phase synchronous motor drives including start-up. To investigate the transient response of the voltage -source fed-synchronous motor drives, a digital computer program is developed. The program is based on two models --machine model and inverter model. The machine is represented by a detailed two-axis model which includes the effects due to saliency, damper windings, and machine resistances. The inverter model represents a forced-commutated voltage-source inverter assuming ideal switching devices (thyristors and diodes). To cope with the wide variations of power factor during start-up, a thyristor with a reverse connected parallel diode are integrated as a bidirectional switch. The digital program provides the machine variables of interest (phase currents, field current, damper winding

  15. Spatio-temporal behavior of microwave sheath-voltage combination plasma source

    NASA Astrophysics Data System (ADS)

    Kar, Satyananda; Kousaka, Hiroyuki; Raja, Laxminarayan L.

    2015-05-01

    Microwave sheath-Voltage combination Plasma (MVP) is a high density plasma source and can be used as a suitable plasma processing device (e.g., ionized physical vapor deposition). In the present report, the spatio-temporal behavior of an argon MVP sustained along a direct-current biased Ti rod is investigated. Two plasma modes are observed, one is an "oxidized state" (OS) at the early time of the microwave plasma and the other is "ionized sputter state" (ISS) at the later times. Transition of the plasma from OS to ISS results a prominent change in the visible color of the plasma, resulting from a significant increase in the plasma density, as measured by a Langmuir probe. In the OS, plasma is dominated by Ar ions, and the density is in amplitude order of 1011 cm-3. In the ISS, metal ions from the Ti rod contribute significantly to the ion composition, and higher density plasma (1012 cm-3) is produced. Nearly uniform high density plasma along the length of the Ti rod is produced at very low input microwave powers (around 30 W). Optical emission spectroscopy measurements confirm the presence of sputtered Ti ions and Ti neutrals in the ISS.

  16. 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-source

  17. Photovoltaic on-demand high-voltage pulse generator as an on-board power source for electrostatic actuator array

    NASA Astrophysics Data System (ADS)

    Lee, Jeong-Bong; Allen, Mark G.; Rohatgi, Ajeet

    1999-09-01

    The use of amorphous silicon solar cell array high voltage power source as an on-demand wireless power source for electrostatically actuated 32 X 32 micromirror array is presented. The amorphous silicon solar cell array has been reported previously by authors of this paper. In this work, the solar cell array has been used to drive distributed electrostatic actuator array (micromirror array in this particular paper). A 32 X 32 micromirror array has been fabricated and the size of single micromirror is 200 micrometer X 200 micrometer. Static deflection test of micromirrors has been carried out and pull-in voltage of 44 V and releasing voltage of 30 V was found. The electrical output of the solar cell array has been directly connected to the 32 X 32 micromirror array to demonstrate a wireless powered distributed MEMS actuator array. A total solar cell array area of 0.3 cm2 (30 series-interconnected solar cells) were used to drive a part of 32 X 32 micromirror array (a total array area of 0.4 cm2). Motion of multiple numbers of micromirrors was reproducibly observed. The ultimate goal of this research is to achieve power-integrated autonomous MEMS using solar cell array as a miniaturized wireless on-board power source and distributed actuator array as a locomotive engine.

  18. Microfluidic circuit designs for performing electrokinetic manipulations that reduce the number of voltage sources and fluid reservoirs

    SciTech Connect

    Jacobson, S.C.; Ramsey, J.M.

    2000-05-16

    A microfabricated device and method for proportioning and mixing electrokinetically manipulated biological or chemical materials is disclosed. The microfabricated device mixes a plurality of materials in volumetric proportions controlled by the electrical resistances of tributary reagent channels through which the materials are transported. The microchip includes two or more tributary reagent channels combining at one or more junctions to form one or more mixing channels. By varying the geometries of the channels (length, cross section, etc.), a plurality of reagent materials can be mixed at a junction such that the proportions of the reagent materials in the mixing channel depend on a ratio of the channel geometries and material properties. Such an approach facilitates voltage division on the microchip without relying on external wiring schemes and voltage division techniques external to the microchip. Microchannel designs that provide the necessary voltage division to accomplish electrokinetic valving operations using a single voltage source and a switch are also described. In addition, microchannel designs that accomplish fluidic operation utilizing a minimal number of fluidic reservoirs are disclosed.

  19. MicrofluIdic circuit designs for performing electrokinetic manipulations that reduce the number of voltage sources and fluid reservoirs

    DOEpatents

    Jacobson, Stephen C.; Ramsey, J. Michael

    2000-01-01

    A microfabricated device and method for proportioning and mixing electrokinetically manipulated biological or chemical materials is disclosed. The microfabricated device mixes a plurality of materials in volumetric proportions controlled by the electrical resistances of tributary reagent channels through which the materials are transported. The microchip includes two or more tributary reagent channels combining at one or more junctions to form one or more mixing channels. By varying the geometries of the channels (length, cross section, etc.), a plurality of reagent materials can be mixed at a junction such that the proportions of the reagent materials in the mixing channel depend on a ratio of the channel geometries and material properties. Such an approach facilitates voltage division on the microchip without relying on external wiring schemes and voltage division techniques external to the microchip. Microchannel designs that provide the necessary voltage division to accomplish electrokinetic valving operations using a single voltage source and a switch are also described. In addition, microchannel designs that accomplish fluidic operation utilizing a minimal number of fluidic reservoirs are disclosed.

  20. Testing Single Phase IGBT H-Bridge Switch Plates for the High Voltage Converter Modulator at the Spallation Neutron Source

    SciTech Connect

    Peplov, Vladimir V; Anderson, David E; Solley, Dennis J

    2014-01-01

    Three IGBT H-bridge switching networks are used in each High Voltage Converter Modulator (HVCM) system at the Spallation Neutron Source (SNS) to generate drive currents to three boost transformer primaries switching between positive and negative bus voltages at 20 kHz. Every switch plate assembly is tested before installing it into an operational HVCM. A Single Phase Test Stand has been built for this purpose, and it is used for adjustment, measurement and testing of different configurations of switch plates. This paper will present a description of the Test Stand configuration and discuss the results of testing switch plates with two different types of IGBT gate drivers currently in use on the HVCM systems. Comparison of timing characteristics of the original and new drivers and the resulting performance reinforces the necessity to replace the original H-bridge network drivers with the upgraded units.

  1. Improvement of voltage holding capability in the 500 keV negative ion source for JT-60SA.

    PubMed

    Tanaka, Y; Hanada, M; Kojima, A; Akino, N; Shimizu, T; Ohshima, K; Inoue, T; Watanabe, K; Taniguchi, M; Kashiwagi, M; Umeda, N; Tobari, H; Grisham, L R

    2010-02-01

    Voltage holding capability of JT-60 negative ion source that has a large electrostatic negative ion accelerator with 45 cm x 1.1 m acceleration grids was experimentally examined and improved to realize 500 keV, 22 A, and 100 s D- ion beams for JT-60 Super Advanced. The gap lengths in the acceleration stages were extended to reduce electric fields in a gap between the large grids and at the corner of the support flanges from the original 4-5 to 3-4 kV/mm. As a result, the voltage holding capability without beam acceleration has been successfully improved from 400 to 500 kV. The pulse duration to hold 500 kV reached 40 s of the power supply limitation.

  2. Voltage management of distribution networks with high penetration of distributed photovoltaic generation sources

    NASA Astrophysics Data System (ADS)

    Alyami, Saeed

    Installation of photovoltaic (PV) units could lead to great challenges to the existing electrical systems. Issues such as voltage rise, protection coordination, islanding detection, harmonics, increased or changed short-circuit levels, etc., need to be carefully addressed before we can see a wide adoption of this environmentally friendly technology. Voltage rise or overvoltage issues are of particular importance to be addressed for deploying more PV systems to distribution networks. This dissertation proposes a comprehensive solution to deal with the voltage violations in distribution networks, from controlling PV power outputs and electricity consumption of smart appliances in real time to optimal placement of PVs at the planning stage. The dissertation is composed of three parts: the literature review, the work that has already been done and the future research tasks. An overview on renewable energy generation and its challenges are given in Chapter 1. The overall literature survey, motivation and the scope of study are also outlined in the chapter. Detailed literature reviews are given in the rest of chapters. The overvoltage and undervoltage phenomena in typical distribution networks with integration of PVs are further explained in Chapter 2. Possible approaches for voltage quality control are also discussed in this chapter, followed by the discussion on the importance of the load management for PHEVs and appliances and its benefits to electric utilities and end users. A new real power capping method is presented in Chapter 3 to prevent overvoltage by adaptively setting the power caps for PV inverters in real time. The proposed method can maintain voltage profiles below a pre-set upper limit while maximizing the PV generation and fairly distributing the real power curtailments among all the PV systems in the network. As a result, each of the PV systems in the network has equal opportunity to generate electricity and shares the responsibility of voltage

  3. A Mathematical Model to Predict Voltage Fluctuations in a Distribution System with Renewable Energy Sources

    NASA Astrophysics Data System (ADS)

    Iyer, Shivkumar Venkatraman; Wu, Bin; Li, Yunwei; Singh, Birendra

    2015-12-01

    This paper proposes a simplified mathematical model to predict the impact of connection of Distributed Generators (DGs) to the ac grid. The model allows the user to examine the fluctuations in the magnitude of voltages at different nodes in the distribution system. In order to use the model, the user does not require a commercial simulation software making it a handy tool for a practicing engineer. Analysis has been presented to describe how the detailed mathematical model of the system is reduced using elementary matrix manipulation techniques to obtain the final simplified mathematical model. Simulation results are presented to verify the mathematical model with a ring distribution system with three DGs connected to it and the results validate those attained from the mathematical model.

  4. A Novel Method of Suppressing the Inrush Current of Transformers Using a Series-Connected Voltage-Source PWM Converter

    NASA Astrophysics Data System (ADS)

    Yamada, Hiroaki; Tanaka, Toshihiko; Funabiki, Shigeyuki

    This paper proposes a novel method of suppressing the inrush current of transformers. A small-rated voltage-source PWM converter is connected in series to the transformers through a matching transformer. As the connected PWM converter performs a resistor for the source current, no inrush phenomena occurs. The required-ratings of the PWM converter, which performs the damping resistor for the inrush phenomena, is one-four-hundredth as compared to that of the main transformers in single-phase circuits. In three-phase circuits, it is one-nine-hundredth. The basic principle of the proposed method is discussed. Digital computer simulation is implemented to confirm the validity and excellent practicability of the proposed method using the PSCAD/EMTDC. A prototype experimental-model is constructed and tested. The experimental results demonstrate that the proposed method can perfectly suppress the inrush phenomena.

  5. A low-frequency high-voltage rf-barrier-bunching system for high-intensity neutron source compressor rings

    SciTech Connect

    Hardek, T.W.; Ziomek, C.; Rees, D.

    1995-05-01

    A Los Alamos design for a 1-MW pulsed neutron source incorporates a ring utilizing an rf-barrier bunching system. This bunching concept allows uniform longitudinal beam distributions with low momentum spread. Bunching cavities are operated at the revolution frequency (1.5 MHz in this case) and each of the 2nd, 3rd, 4th, and 5th revolution frequency harmonics. Their effects combine to maintain a beam free gap in the longitudinal distribution of the accumulated beam. The cavities are driven by low-plate-resistance common-cathode configured retrode amplifiers incorporating local rf feedback. Additional adaptive feed-forward hardware is included to reduce the beam-induced bunching-gap voltages well below that achievable solely with rf feedback. Details of this system are presented along with a discussion of the various feed-back and feed-forward techniques incorporated.

  6. A dual-energy medical instrument for measurement of x-ray source voltage and dose rate

    NASA Astrophysics Data System (ADS)

    Ryzhikov, V. D.; Naydenov, S. V.; Volkov, V. G.; Opolonin, O. D.; Makhota, S.; Pochet, T.; Smith, C. F.

    2016-03-01

    An original dual-energy detector and medical instrument have been developed to measure the output voltages and dose rates of X-ray sources. Theoretical and experimental studies were carried out to characterize the parameters of a new scintillator-photodiode sandwich-detector based on specially-prepared zinc selenide crystals in which the low-energy detector (LED) works both as the detector of the low-energy radiation and as an absorption filter allowing the highenergy fraction of the radiation to pass through to the high-energy detector (HED). The use of the LED as a low-energy filter in combination with a separate HED opens broad possibilities for such sandwich structures. In particular, it becomes possible to analyze and process the sum, difference and ratio of signals coming from these detectors, ensuring a broad (up to 106) measurement range of X-ray intensity from the source and a leveling of the energy dependence. We have chosen an optimum design of the detector and the geometry of the component LED and HED parts that allow energy-dependence leveling to within specified limits. The deviation in energy dependence of the detector does not exceed about 5% in the energy range from 30 to 120 keV. The developed detector and instrument allow contactless measurement of the anode voltage of an X-ray emitter from 40 to 140 kV with an error no greater than 3%. The dose rate measurement range is from 1 to 200 R/min. An original medical instrument has passed clinical testing and was recommended for use in medical institutions for X-ray diagnostics.

  7. Characteristics of temperature rise in variable inductor employing magnetorheological fluid driven by a high-frequency pulsed voltage source

    NASA Astrophysics Data System (ADS)

    Lee, Ho-Young; Kang, In Man; Shon, Chae-Hwa; Lee, Se-Hee

    2015-05-01

    A variable inductor with magnetorheological (MR) fluid has been successfully applied to power electronics applications; however, its thermal characteristics have not been investigated. To evaluate the performance of the variable inductor with respect to temperature, we measured the characteristics of temperature rise and developed a numerical analysis technique. The characteristics of temperature rise were determined experimentally and verified numerically by adopting a multiphysics analysis technique. In order to accurately estimate the temperature distribution in a variable inductor with an MR fluid-gap, the thermal solver should import the heat source from the electromagnetic solver to solve the eddy current problem. To improve accuracy, the B-H curves of the MR fluid under operating temperature were obtained using the magnetic property measurement system. In addition, the Steinmetz equation was applied to evaluate the core loss in a ferrite core. The predicted temperature rise for a variable inductor showed good agreement with the experimental data and the developed numerical technique can be employed to design a variable inductor with a high-frequency pulsed voltage source.

  8. Characteristics of temperature rise in variable inductor employing magnetorheological fluid driven by a high-frequency pulsed voltage source

    SciTech Connect

    Lee, Ho-Young; Kang, In Man; Shon, Chae-Hwa; Lee, Se-Hee

    2015-05-07

    A variable inductor with magnetorheological (MR) fluid has been successfully applied to power electronics applications; however, its thermal characteristics have not been investigated. To evaluate the performance of the variable inductor with respect to temperature, we measured the characteristics of temperature rise and developed a numerical analysis technique. The characteristics of temperature rise were determined experimentally and verified numerically by adopting a multiphysics analysis technique. In order to accurately estimate the temperature distribution in a variable inductor with an MR fluid-gap, the thermal solver should import the heat source from the electromagnetic solver to solve the eddy current problem. To improve accuracy, the B–H curves of the MR fluid under operating temperature were obtained using the magnetic property measurement system. In addition, the Steinmetz equation was applied to evaluate the core loss in a ferrite core. The predicted temperature rise for a variable inductor showed good agreement with the experimental data and the developed numerical technique can be employed to design a variable inductor with a high-frequency pulsed voltage source.

  9. Measurement of Parasitic Inductances in the Bus-Bar Assembly of a High Power Voltage Source Converter

    NASA Astrophysics Data System (ADS)

    Datta, Aniket; Narayanan, G.

    2016-05-01

    Insulated gate bipolar transistor (IGBT) based voltage source converters use copper plates with insulating sheets in between them (sandwich bus-bar arrangement) for connecting the different device terminals in the power circuit. In such converters, the parasitic inductances in the power circuit are crucial as they cause overvoltage spikes across the device. Also, the parasitics affect the current sharing between IGBTs when they are connected in parallel in high power converters. The conduction path through plates and fasteners in the bus-bar assembly is three-dimensional and quite complex, making analytical evaluation of the stray inductance quite challenging. The first objective here is to present a simple experimental setup and experimental procedure, which are convenient for power electronic engineers, to measure the bus-bar inductance. The next objective is to carry out experimental studies on the inductances offered by different components and sub-assemblies in a bus-bar assembly. This includes evaluation of inductances of the different conduction paths in typical bus-bar plates. The third objective is to experimentally evaluate the parasitic inductances in the bus-bar assembly of a commercial 250 kVA high power converter. Each leg of this converter consists of two 300 A/1200 V IGBTs connected in parallel. The effective inductance seen by the individual device modules are determined experimentally.

  10. Pulsed Operation of a Compact Fusion Neutron Source Using a High-Voltage Pulse Generator Developed for Landmine Detection

    SciTech Connect

    Yamauchi, Kunihito; Watanabe, Masato; Okino, Akitoshi; Kohno, Toshiyuki; Hotta, Eiki; Yuura, Morimasa

    2005-05-15

    Preliminary experimental results of pulsed neutron source based on a discharge-type beam fusion called Inertial Electrostatic Confinement Fusion (IECF) for landmine detection are presented. In Japan, a research and development project for constructing an advanced anti-personnel landmine detection system by using IECF, which is effective not only for metal landmines but also for plastic ones, is now in progress. This project consists of some R and D topics, and one of them is R and D of a high-voltage pulse generator system specialized for landmine detection, which can be used in the severe environment such as that in the field in Afghanistan. Thus a prototype of the system for landmine detection was designed and fabricated in consideration of compactness, lightness, cooling performance, dustproof and robustness. By using this prototype pulse generator system, a conventional IECF device was operated as a preliminary experiment. As a result, it was confirmed that the suggested pulse generator system is suitable for landmine detection system, and the results follow the empirical law obtained by the previous experiments. The maximum neutron production rate of 2.0x10{sup 8} n/s was obtained at a pulsed discharge of -51 kV, 7.3 A.

  11. An Analytical Threshold Voltage Model of Fully Depleted (FD) Recessed-Source/Drain (Re-S/D) SOI MOSFETs with Back-Gate Control

    NASA Astrophysics Data System (ADS)

    Saramekala, Gopi Krishna; Tiwari, Pramod Kumar

    2016-10-01

    This paper presents an analytical threshold voltage model for back-gated fully depleted (FD), recessed-source drain silicon-on-insulator metal-oxide-semiconductor field-effect transistors (MOSFETs). Analytical surface potential models have been developed at front and back surfaces of the channel by solving the two-dimensional (2-D) Poisson's equation in the channel region with appropriate boundary conditions assuming a parabolic potential profile in the transverse direction of the channel. The strong inversion criterion is applied to the front surface potential as well as on the back one in order to find two separate threshold voltages for front and back channels of the device, respectively. The device threshold voltage has been assumed to be associated with the surface that offers a lower threshold voltage. The developed model was analyzed extensively for a variety of device geometry parameters like the oxide and silicon channel thicknesses, the thickness of the source/drain extension in the buried oxide, and the applied bias voltages with back-gate control. The proposed model has been validated by comparing the analytical results with numerical simulation data obtained from ATLAS™, a 2-D device simulator from SILVACO.

  12. An Analytical Threshold Voltage Model of Fully Depleted (FD) Recessed-Source/Drain (Re-S/D) SOI MOSFETs with Back-Gate Control

    NASA Astrophysics Data System (ADS)

    Saramekala, Gopi Krishna; Tiwari, Pramod Kumar

    2016-06-01

    This paper presents an analytical threshold voltage model for back-gated fully depleted (FD), recessed-source drain silicon-on-insulator metal-oxide-semiconductor field-effect transistors (MOSFETs). Analytical surface potential models have been developed at front and back surfaces of the channel by solving the two-dimensional (2-D) Poisson's equation in the channel region with appropriate boundary conditions assuming a parabolic potential profile in the transverse direction of the channel. The strong inversion criterion is applied to the front surface potential as well as on the back one in order to find two separate threshold voltages for front and back channels of the device, respectively. The device threshold voltage has been assumed to be associated with the surface that offers a lower threshold voltage. The developed model was analyzed extensively for a variety of device geometry parameters like the oxide and silicon channel thicknesses, the thickness of the source/drain extension in the buried oxide, and the applied bias voltages with back-gate control. The proposed model has been validated by comparing the analytical results with numerical simulation data obtained from ATLAS™, a 2-D device simulator from SILVACO.

  13. Deposition and characterization of zirconium nitride (ZrN) thin films by reactive magnetron sputtering with linear gas ion source and bias voltage

    NASA Astrophysics Data System (ADS)

    Kavitha, A.; Subramanian, N. Sankara; Loganathan, S.; Kannan, R.

    2014-04-01

    Zirconium nitride thin films have been prepared on stainless steel substrate (304L grade) by reactive cylindrical magnetron sputtering method with Gas Ion Source (GIS) and bias voltage using optimized coating parameters. The structure and surface morphologies of the ZrN films were characterized using X-ray diffraction, atomic microscopy and scanning electron microscopy. The adhesion property of ZrN thin film has been increased due to the GIS. The coating exhibits better adhesion strength up to 10 N whereas the ZrN thin film with bias voltage exhibits adhesion up to 500 mN.

  14. Deposition and characterization of zirconium nitride (ZrN) thin films by reactive magnetron sputtering with linear gas ion source and bias voltage

    SciTech Connect

    Kavitha, A.; Kannan, R.; Subramanian, N. Sankara; Loganathan, S.

    2014-04-24

    Zirconium nitride thin films have been prepared on stainless steel substrate (304L grade) by reactive cylindrical magnetron sputtering method with Gas Ion Source (GIS) and bias voltage using optimized coating parameters. The structure and surface morphologies of the ZrN films were characterized using X-ray diffraction, atomic microscopy and scanning electron microscopy. The adhesion property of ZrN thin film has been increased due to the GIS. The coating exhibits better adhesion strength up to 10 N whereas the ZrN thin film with bias voltage exhibits adhesion up to 500 mN.

  15. Array of solid-state dye-sensitized solar cells with micropatterned TiO2 nanoparticles for a high-voltage power source.

    PubMed

    Cho, Seong-Min; Park, Hea-Lim; Kim, Min-Hoi; Kim, Se-Um; Lee, Sin-Doo

    2013-11-20

    We demonstrate an array of solid-state dye-sensitized solar cells (SS-DSSCs) for a high-voltage power source based on micropatterned titanium dioxide nanoparticles (TNPs) as photoanodes connected in series. The underlying concept of patterning the TNP of a few micrometers thick lies on the combination of the lift-off process of transfer-printed patterns of a sacrificial layer and the soft-cure treatment of the TNP for fixation. This sacrificial layer approach allows for high pattern fidelity and stability, and it enables to construct stable, micrometer-thick, and contamination-free TNP patterns for developing the SS-DSSC array for miniature high-voltage applications. The array of 20 SS-DSSCs integrated in series is found to show a voltage output of around 7 V.

  16. 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.

  17. 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.

  18. The Application of Auto-Disturbance Rejection Control Optimized by Least Squares Support Vector Machines Method and Time-Frequency Representation in Voltage Source Converter-High Voltage Direct Current System.

    PubMed

    Liu, Ying-Pei; Liang, Hai-Ping; Gao, Zhong-Ke

    2015-01-01

    In order to improve the performance of voltage source converter-high voltage direct current (VSC-HVDC) system, we propose an improved auto-disturbance rejection control (ADRC) method based on least squares support vector machines (LSSVM) in the rectifier side. Firstly, we deduce the high frequency transient mathematical model of VSC-HVDC system. Then we investigate the ADRC and LSSVM principles. We ignore the tracking differentiator in the ADRC controller aiming to improve the system dynamic response speed. On this basis, we derive the mathematical model of ADRC controller optimized by LSSVM for direct current voltage loop. Finally we carry out simulations to verify the feasibility and effectiveness of our proposed control method. In addition, we employ the time-frequency representation methods, i.e., Wigner-Ville distribution (WVD) and adaptive optimal kernel (AOK) time-frequency representation, to demonstrate our proposed method performs better than the traditional method from the perspective of energy distribution in time and frequency plane.

  19. The Application of Auto-Disturbance Rejection Control Optimized by Least Squares Support Vector Machines Method and Time-Frequency Representation in Voltage Source Converter-High Voltage Direct Current System

    PubMed Central

    Gao, Zhong-Ke

    2015-01-01

    In order to improve the performance of voltage source converter-high voltage direct current (VSC-HVDC) system, we propose an improved auto-disturbance rejection control (ADRC) method based on least squares support vector machines (LSSVM) in the rectifier side. Firstly, we deduce the high frequency transient mathematical model of VSC-HVDC system. Then we investigate the ADRC and LSSVM principles. We ignore the tracking differentiator in the ADRC controller aiming to improve the system dynamic response speed. On this basis, we derive the mathematical model of ADRC controller optimized by LSSVM for direct current voltage loop. Finally we carry out simulations to verify the feasibility and effectiveness of our proposed control method. In addition, we employ the time-frequency representation methods, i.e., Wigner-Ville distribution (WVD) and adaptive optimal kernel (AOK) time-frequency representation, to demonstrate our proposed method performs better than the traditional method from the perspective of energy distribution in time and frequency plane. PMID:26098556

  20. 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.

  1. Preparation of diamond-like carbon films using reactive Ar/CH4 high power impulse magnetron sputtering system with negative pulse voltage source for substrate

    NASA Astrophysics Data System (ADS)

    Kimura, Takashi; Kamata, Hikaru

    2016-04-01

    Diamond-like carbon films were prepared using a reactive Ar/CH4 high-power impulse magnetron sputtering system with a negative pulse voltage source for the substrate, changing the CH4 fraction up to 15% in the total pressure range from 0.3 to 2 Pa. The magnitude of the negative pulse voltage for the substrate was also varied up to about 500 V. The hardness of films monotonically increased with increasing magnitude of the negative pulse voltage. The films with hardnesses between 16.5 and 23 GPa were prepared at total pressures less than 0.5 Pa and CH4 fractions less than 10% by applying an appropriate negative pulse voltage of 300-400 V. In X-ray photoelectron spectroscopy, the area ratio C-C sp3/(C-C sp2 + C-C sp3) in the C 1s core level was higher than 30% at pressures less than 0.5 Pa and CH4 fractions less than 15%. On the other hand, the films with hardnesses between 5 and 10 GPa were prepared with a relatively high growth rate at the partial pressures of CH4 higher than 0.1 Pa. However, the observation of the photoluminescence background in Raman spectroscopy indicated a relatively high hydrogen content.

  2. Power trench gate MOSFET with an integrated 6-pack configuration for a 3-phase inverter

    NASA Astrophysics Data System (ADS)

    Won, Jong-Il; Koo, Jin-Gun; Cho, Doo-Hyung; Park, Kun-Sik; Yang, Yil-Suk; Kim, Sang-Gi

    2015-10-01

    In this paper, we present a new 6-pack power module for a 3-phase inverter that is integrated with the six trench gate double diffused metal-oxide semiconductor field-effect transistor (TDMOS) on a single chip. An integration of each power device is performed through a trench isolation technique using deep reactive-ion etching trench technologies. Through this new technology, the integrated power metal-oxide semiconductor field-effect transistor (MOSFET) produces a high current of above 30 A at a gate bias of 10 V. In addition, each trench power MOSFET (1-pack) has a minimum specific on-resistance of 21 mohm.cm2 and a typical breakdown voltage of 95 V. The trench isolation provides good isolation up to 120 V. The measurement results show that this 6-pack structure can successfully be integrated with other analog/driver integrated circuit on a single chip. Furthermore, to monitor the operating current of the MOSFET under an inverter-operating condition, sensing FET is integrated a FET into the main MOSFET source region without compromising either the area or the operation of the MOSFET.

  3. 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.

  4. 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)

  5. Voltage-Boosting Driver For Switching Regulator

    NASA Technical Reports Server (NTRS)

    Trump, Ronald C.

    1990-01-01

    Driver circuit assures availability of 10- to 15-V gate-to-source voltage needed to turn on n-channel metal oxide/semiconductor field-effect transistor (MOSFET) acting as switch in switching voltage regulator. Includes voltage-boosting circuit efficiently providing gate voltage 10 to 15 V above supply voltage. Contains no exotic parts and does not require additional power supply. Consists of NAND gate and dual voltage booster operating in conjunction with pulse-width modulator part of regulator.

  6. [Flow of high-voltage current in coal electrodes of arc furnaces as a source of noise of special nature].

    PubMed

    Polanowska, R

    1984-01-01

    The noise level for working arc furnace has been measured. Arc furnaces were found to be the source of infrasounds and acoustic field. The sound pressure levels for infrasounds range from 55 to 77 dB. It has been showed that particular noise level includes the onethird-octave band with middle frequency 100 Hz. The sound pressure levels in this band range from 105 to 110 dB.

  7. A study of the effect on human mesenchymal stem cells of an atmospheric pressure plasma source driven by different voltage waveforms

    NASA Astrophysics Data System (ADS)

    Laurita, R.; Alviano, F.; Marchionni, C.; Abruzzo, P. M.; Bolotta, A.; Bonsi, L.; Colombo, V.; Gherardi, M.; Liguori, A.; Ricci, F.; Rossi, M.; Stancampiano, A.; Tazzari, P. L.; Marini, M.

    2016-09-01

    The effect of an atmospheric pressure non-equilibrium plasma on human mesenchymal stem cells was investigated. A dielectric barrier discharge non-equilibrium plasma source driven by two different high-voltage pulsed generators was used and cell survival, senescence, proliferation, and differentiation were evaluated. Cells deprived of the culture medium and treated with nanosecond pulsed plasma showed a higher mortality rate, while higher survival and retention of proliferation were observed in cells treated with microsecond pulsed plasma in the presence of the culture medium. While a few treated cells showed the hallmarks of senescence, unexpected delayed apoptosis ensued in cells exposed to plasma-treated medium. The plasma treatment did not change the expression of OCT4, a marker of mesenchymal stem cell differentiation.

  8. Parametric effect of a spatially periodic voltage depression on operation of [hacek C]erenkov sources of electromagnetic radiation

    SciTech Connect

    Nusinovich, G.S.; Vlasov, A.N. )

    1994-03-01

    In microwave sources of coherent [hacek C]erenkov radiation the electrons usually propagate near the rippled wall of a slow-wave structure. These ripples cause the periodic modulation of electron potential depression, and therefore, lead to periodic modulation of electron axial velocities. Since the period of this electrostatic pumping is the period of the slow-wave structure the parametric coupling of electrons to originally nonsynchronous spatial harmonics of the microwave field may occur. This effect can be especially important for backward-wave oscillators (BWO's) driven by high current, relativistic electron beams. In the paper both linear and nonlinear theories of the relativistic resonant BWO with periodic modulation of electron axial velocities are developed and results illustrating the evolution of the linear gain function and the efficiency of operation in the large-signal regime are presented.

  9. An electrostatic 3-phase linear stepper motor fabricated by vertical trench isolation technology

    NASA Astrophysics Data System (ADS)

    Sarajlic, Edin; Yamahata, Christophe; Cordero, Mauricio; Fujita, Hiroyuki

    2009-07-01

    We present the design, microfabrication and characterization of an electrostatic 3-phase linear stepper micromotor constructed with vertical trench isolation technology. This suitable technology was used to create a monolithic stepper motor with high-aspect-ratio poles and an integrated 3-phase electrical network in the bulk of a standard single-crystal silicon wafer. The shuttle of the stepper motor is suspended by a flexure to avoid any mechanical contact during operation, enhancing the precision, repeatability and reliability of the stepping motion. The prototype is capable of a maximum travel of +/-26 µm (52 µm) at an actuation voltage of 30 V and a step size of 1.4 µm during a half-stepping sequence. This work was presented in part at the 19th MicroMechanics Europe Workshop (MME), 28-30 September 2008, Aachen, Germany.

  10. 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.

  11. Tuning and Cold Test of a Four-Vane RFQ with Ramped Inter-Vane Voltage for the Compact Pulsed Hadron Source

    NASA Astrophysics Data System (ADS)

    Xing, Qing-Zi; Du, Lei; Zheng, Shu-Xin; Guan, Xia-Ling; Li, Jian; Cai, Jin-Chi; Gong, Cun-Kui; Wang, Xue-Wu; Tang, Chuan-Xiang; James, Billen; James, Stovall; Lloyd, Young

    2013-05-01

    A four-vane radio-frequency quadrupole (RFQ) accelerator is under construction for the Compact Pulsed Hadron Source (CPHS) project at Tsinghua University. The 3 m-long RFQ will accelerate a 50keV proton beam from the ECR source to 3MeV, and deliver it to the downstream drift tube linac (DTL) with a peak current of 50mA, pulse length of 0.5 ms and beam duty factor of 2.5%. The inter-vane voltage is designed to increase with the longitudinal position to produce a short RFQ. Coupling plates are therefore not necessary. The cavity cross section and vane-tip geometry are tailored as a function of the longitudinal position, while limiting the peak surface electric field to 1.8 Kilpatrick. The RFQ is designed, manufactured, and installed at Tsinghua University. We also present the tuning and cold test results of the RFQ accelerator. After final tuning, the relative error of the quadrupole field is within 2%, and the admixture of the two dipole modes are less than 2% of the quadrupole mode.

  12. Distribution System Voltage Regulation by Distributed Energy Resources

    SciTech Connect

    Ceylan, Oguzhan; Liu, Guodong; Xu, Yan; Tomsovic, Kevin

    2014-01-01

    This paper proposes a control method to regulate voltages in 3 phase unbalanced electrical distribution systems. A constrained optimization problem to minimize voltage deviations and maximize distributed energy resource (DER) active power output is solved by harmony search algorithm. IEEE 13 Bus Distribution Test System was modified to test three different cases: a) only voltage regulator controlled system b) only DER controlled system and c) both voltage regulator and DER controlled system. The simulation results show that systems with both voltage regulators and DER control provide better voltage profile.

  13. Fault diagnosis and fault-tolerant finite control set-model predictive control of a multiphase voltage-source inverter supplying BLDC motor.

    PubMed

    Salehifar, Mehdi; Moreno-Equilaz, Manuel

    2016-01-01

    Due to its fault tolerance, a multiphase brushless direct current (BLDC) motor can meet high reliability demand for application in electric vehicles. The voltage-source inverter (VSI) supplying the motor is subjected to open circuit faults. Therefore, it is necessary to design a fault-tolerant (FT) control algorithm with an embedded fault diagnosis (FD) block. In this paper, finite control set-model predictive control (FCS-MPC) is developed to implement the fault-tolerant control algorithm of a five-phase BLDC motor. The developed control method is fast, simple, and flexible. A FD method based on available information from the control block is proposed; this method is simple, robust to common transients in motor and able to localize multiple open circuit faults. The proposed FD and FT control algorithm are embedded in a five-phase BLDC motor drive. In order to validate the theory presented, simulation and experimental results are conducted on a five-phase two-level VSI supplying a five-phase BLDC motor. PMID:26549566

  14. Fault diagnosis and fault-tolerant finite control set-model predictive control of a multiphase voltage-source inverter supplying BLDC motor.

    PubMed

    Salehifar, Mehdi; Moreno-Equilaz, Manuel

    2016-01-01

    Due to its fault tolerance, a multiphase brushless direct current (BLDC) motor can meet high reliability demand for application in electric vehicles. The voltage-source inverter (VSI) supplying the motor is subjected to open circuit faults. Therefore, it is necessary to design a fault-tolerant (FT) control algorithm with an embedded fault diagnosis (FD) block. In this paper, finite control set-model predictive control (FCS-MPC) is developed to implement the fault-tolerant control algorithm of a five-phase BLDC motor. The developed control method is fast, simple, and flexible. A FD method based on available information from the control block is proposed; this method is simple, robust to common transients in motor and able to localize multiple open circuit faults. The proposed FD and FT control algorithm are embedded in a five-phase BLDC motor drive. In order to validate the theory presented, simulation and experimental results are conducted on a five-phase two-level VSI supplying a five-phase BLDC motor.

  15. Analysis of coronary arterial calcification components with coronary CT angiography using single-source dual-energy CT with fast tube voltage switching.

    PubMed

    Matsui, Kazuhiro; Machida, Haruhiko; Mitsuhashi, Tetsuya; Omori, Hisako; Nakaoka, Takashi; Sakura, Hiroshi; Ueno, Eiko

    2015-03-01

    Clinical cardiac applications of single-source dual-energy computed tomography (DECT) have recently been introduced. This study aimed to analyze the components of coronary arterial calcification (CAC) in vivo by material decomposition achieved with DECT. We reconstructed computed tomography (CT) angiography images for 51 consecutive patients with CACs who had undergone electrocardiography-gated coronary CT angiography by single-source DECT with fast tube voltage switching. We placed regions of interest (ROIs) within the CAC with margins of at least 0.5 mm to minimize partial volume averaging. We compared histograms for the effective atomic number (EAN) and the median, mean, and maximum EANs for each CAC with the theoretical EANs for possible CAC components, including hydroxyapatite (HA), calcium oxalate monohydrate (COM), and dicalcium phosphate dehydrate. We also investigated the in vivo EAN for COM and in vitro EAN for HA by our phantom experiment. Analysis of the CAC components was feasible in 177 ROIs from 28 patients. The median EAN was 13.8 ± 0.8 (95% confidence interval 13.7-13.9), which is similar to the theoretical EAN for COM (13.8). The EAN for HA in vitro was 16.5 ± 0.1, which was slightly higher than the theoretical EAN value for HA (16.1). Notably, the median EAN in 144 ROIs (81.4%) was between 11.2 and 14.4, which is the reported range of the in vivo EAN for COM. Our results suggest that COM might be a more frequent CAC component than previously reported. PMID:25407480

  16. High voltage MOSFET switching circuit

    DOEpatents

    McEwan, T.E.

    1994-07-26

    The problem of source lead inductance in a MOSFET switching circuit is compensated for by adding an inductor to the gate circuit. The gate circuit inductor produces an inductive spike which counters the source lead inductive drop to produce a rectangular drive voltage waveform at the internal gate-source terminals of the MOSFET. 2 figs.

  17. High voltage MOSFET switching circuit

    DOEpatents

    McEwan, Thomas E.

    1994-01-01

    The problem of source lead inductance in a MOSFET switching circuit is compensated for by adding an inductor to the gate circuit. The gate circuit inductor produces an inductive spike which counters the source lead inductive drop to produce a rectangular drive voltage waveform at the internal gate-source terminals of the MOSFET.

  18. 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

  19. Nanosecond pulsed electric fields (nsPEFs) low cost generator design using power MOSFET and Cockcroft-Walton multiplier circuit as high voltage DC source

    NASA Astrophysics Data System (ADS)

    Sulaeman, M. Y.; Widita, R.

    2014-09-01

    Purpose: Non-ionizing radiation therapy for cancer using pulsed electric field with high intensity field has become an interesting field new research topic. A new method using nanosecond pulsed electric fields (nsPEFs) offers a novel means to treat cancer. Not like the conventional electroporation, nsPEFs able to create nanopores in all membranes of the cell, including membrane in cell organelles, like mitochondria and nucleus. NsPEFs will promote cell death in several cell types, including cancer cell by apoptosis mechanism. NsPEFs will use pulse with intensity of electric field higher than conventional electroporation, between 20-100 kV/cm and with shorter duration of pulse than conventional electroporation. NsPEFs requires a generator to produce high voltage pulse and to achieve high intensity electric field with proper pulse width. However, manufacturing cost for creating generator that generates a high voltage with short duration for nsPEFs purposes is highly expensive. Hence, the aim of this research is to obtain the low cost generator design that is able to produce a high voltage pulse with nanosecond width and will be used for nsPEFs purposes. Method: Cockcroft-Walton multiplier circuit will boost the input of 220 volt AC into high voltage DC around 1500 volt and it will be combined by a series of power MOSFET as a fast switch to obtain a high voltage with nanosecond pulse width. The motivation using Cockcroft-Walton multiplier is to acquire a low-cost high voltage DC generator; it will use capacitors and diodes arranged like a step. Power MOSFET connected in series is used as voltage divider to share the high voltage in order not to damage them. Results: This design is expected to acquire a low-cost generator that can achieve the high voltage pulse in amount of -1.5 kV with falltime 3 ns and risetime 15 ns into a 50Ω load that will be used for nsPEFs purposes. Further detailed on the circuit design will be explained at presentation.

  20. Nanosecond pulsed electric fields (nsPEFs) low cost generator design using power MOSFET and Cockcroft-Walton multiplier circuit as high voltage DC source

    SciTech Connect

    Sulaeman, M. Y.; Widita, R.

    2014-09-30

    Purpose: Non-ionizing radiation therapy for cancer using pulsed electric field with high intensity field has become an interesting field new research topic. A new method using nanosecond pulsed electric fields (nsPEFs) offers a novel means to treat cancer. Not like the conventional electroporation, nsPEFs able to create nanopores in all membranes of the cell, including membrane in cell organelles, like mitochondria and nucleus. NsPEFs will promote cell death in several cell types, including cancer cell by apoptosis mechanism. NsPEFs will use pulse with intensity of electric field higher than conventional electroporation, between 20–100 kV/cm and with shorter duration of pulse than conventional electroporation. NsPEFs requires a generator to produce high voltage pulse and to achieve high intensity electric field with proper pulse width. However, manufacturing cost for creating generator that generates a high voltage with short duration for nsPEFs purposes is highly expensive. Hence, the aim of this research is to obtain the low cost generator design that is able to produce a high voltage pulse with nanosecond width and will be used for nsPEFs purposes. Method: Cockcroft-Walton multiplier circuit will boost the input of 220 volt AC into high voltage DC around 1500 volt and it will be combined by a series of power MOSFET as a fast switch to obtain a high voltage with nanosecond pulse width. The motivation using Cockcroft-Walton multiplier is to acquire a low-cost high voltage DC generator; it will use capacitors and diodes arranged like a step. Power MOSFET connected in series is used as voltage divider to share the high voltage in order not to damage them. Results: This design is expected to acquire a low-cost generator that can achieve the high voltage pulse in amount of −1.5 kV with falltime 3 ns and risetime 15 ns into a 50Ω load that will be used for nsPEFs purposes. Further detailed on the circuit design will be explained at presentation.

  1. Modular high voltage power supply for chemical analysis

    SciTech Connect

    Stamps, James F.; Yee, Daniel D.

    2010-05-04

    A high voltage power supply for use in a system such as a microfluidics system, uses a DC-DC converter in parallel with a voltage-controlled resistor. A feedback circuit provides a control signal for the DC-DC converter and voltage-controlled resistor so as to regulate the output voltage of the high voltage power supply, as well as, to sink or source current from the high voltage supply.

  2. Modular high voltage power supply for chemical analysis

    DOEpatents

    Stamps, James F.; Yee, Daniel D.

    2007-01-09

    A high voltage power supply for use in a system such as a microfluidics system, uses a DC--DC converter in parallel with a voltage-controlled resistor. A feedback circuit provides a control signal for the DC--DC converter and voltage-controlled resistor so as to regulate the output voltage of the high voltage power supply, as well as, to sink or source current from the high voltage supply.

  3. Modular high voltage power supply for chemical analysis

    SciTech Connect

    Stamps, James F.; Yee, Daniel D.

    2008-07-15

    A high voltage power supply for use in a system such as a microfluidics system, uses a DC-DC converter in parallel with a voltage-controlled resistor. A feedback circuit provides a control signal for the DC-DC converter and voltage-controlled resistor so as to regulate the output voltage of the high voltage power supply, as well as, to sink or source current from the high voltage supply.

  4. Comparative study of SVPWM (space vector pulse width modulation) & SPWM (sinusoidal pulse width modulation) based three phase voltage source inverters for variable speed drive

    NASA Astrophysics Data System (ADS)

    Ahmed, Waheed; Usman Ali, Syed M.

    2013-12-01

    We have performed comparative studies of Space Vector Pulse Width Modulation (SVPWM) and Sinusoidal Pulse Width Modulation (SPWM) techniques utilizing MATLAB tools. During these investigations, we carried out intensive simulations, comprehensively analyzed the obtained results and compared the harmonic density, power factor (PF), & switching losses of SVPWM and SPWM. It has been observed during investigations that if the switching frequency is high then losses due to harmonics are negligible, thus based on obtained results we suggested that the SVPWM technique is a more reliable solution. Because SVPWM utilizes DC bus voltage more efficiently, generates less Total Harmonic Distortion (THD) and has higher output quality it provides flexible control of output voltage and output frequency for Variable Speed Drive (VSD).

  5. High voltage solar array experiments

    NASA Technical Reports Server (NTRS)

    Kennerud, K. L.

    1974-01-01

    The interaction between the components of a high voltage solar array and a simulated space plasma is studied to obtain data for the design of a high voltage solar array capable of 15kW at 2 to 16kV. Testing was conducted in a vacuum chamber 1.5-m long by 1.5-m diameter having a plasma source which simulated the plasma conditions existing in earth orbit between 400 nautical miles and synchronous altitude. Test samples included solar array segments pinholes in insulation covering high voltage electrodes, and plain dielectric samples. Quantitative data are presented in the areas of plasma power losses, plasma and high voltage induced damage, and dielectric properties. Limitations of the investigation are described.

  6. 46 CFR 129.326 - Dual-voltage generators.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Dual-voltage generators. 129.326 Section 129.326... INSTALLATIONS Power Sources and Distribution Systems § 129.326 Dual-voltage generators. If a dual-voltage generator is installed on an OSV— (a) The neutral of the dual-voltage system must be solidly grounded at...

  7. 46 CFR 129.326 - Dual-voltage generators.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Dual-voltage generators. 129.326 Section 129.326... INSTALLATIONS Power Sources and Distribution Systems § 129.326 Dual-voltage generators. If a dual-voltage generator is installed on an OSV— (a) The neutral of the dual-voltage system must be solidly grounded at...

  8. 46 CFR 129.326 - Dual-voltage generators.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Dual-voltage generators. 129.326 Section 129.326... INSTALLATIONS Power Sources and Distribution Systems § 129.326 Dual-voltage generators. If a dual-voltage generator is installed on an OSV— (a) The neutral of the dual-voltage system must be solidly grounded at...

  9. 46 CFR 129.326 - Dual-voltage generators.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Dual-voltage generators. 129.326 Section 129.326... INSTALLATIONS Power Sources and Distribution Systems § 129.326 Dual-voltage generators. If a dual-voltage generator is installed on an OSV— (a) The neutral of the dual-voltage system must be solidly grounded at...

  10. 46 CFR 129.326 - Dual-voltage generators.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Dual-voltage generators. 129.326 Section 129.326... INSTALLATIONS Power Sources and Distribution Systems § 129.326 Dual-voltage generators. If a dual-voltage generator is installed on an OSV— (a) The neutral of the dual-voltage system must be solidly grounded at...

  11. Power conditioning using dynamic voltage restorers under different voltage sag types

    PubMed Central

    Saeed, Ahmed M.; Abdel Aleem, Shady H.E.; Ibrahim, Ahmed M.; Balci, Murat E.; El-Zahab, Essam E.A.

    2015-01-01

    Voltage sags can be symmetrical or unsymmetrical depending on the causes of the sag. At the present time, one of the most common procedures for mitigating voltage sags is by the use of dynamic voltage restorers (DVRs). By definition, a DVR is a controlled voltage source inserted between the network and a sensitive load through a booster transformer injecting voltage into the network in order to correct any disturbance affecting a sensitive load voltage. In this paper, modelling of DVR for voltage correction using MatLab software is presented. The performance of the device under different voltage sag types is described, where the voltage sag types are introduced using the different types of short-circuit faults included in the environment of the MatLab/Simulink package. The robustness of the proposed device is evaluated using the common voltage sag indices, while taking into account voltage and current unbalance percentages, where maintaining the total harmonic distortion percentage of the load voltage within a specified range is desired. Finally, several simulation results are shown in order to highlight that the DVR is capable of effective correction of the voltage sag while minimizing the grid voltage unbalance and distortion, regardless of the fault type. PMID:26843975

  12. The NaNO3-KNO3 phase diagram

    NASA Astrophysics Data System (ADS)

    Benages-Vilau, R.; Calvet, T.; Cuevas-Diarte, M. A.; Oonk, H. A. J.

    2016-01-01

    Many papers have been published in relation to the NaNO3-KNO3 phase diagram determination in the last 160 years. These papers fall in two categories: (1) the solid-liquid equilibrium is assumed to be of the eutectic type, and (2) the solid-liquid equilibrium is considered as a loop with a minimum. The discordance between the two views is related to the slow transition kinetics that complicate the assessment of thermal 'fluctuations', and also to the appearance of a metastable form of potassium nitrate. The main result of this paper is the experimental phase diagram constructed with new experimental data so that we can assure that the second option is correct. This phase diagram is defined by a eutectoid invariant, an asymmetric immiscibility gap and a continuous solid solution with a minimum of melting point. Additionally, the ABθ model simulates correctly the experimental piece of evidence.

  13. A Five-Level Three-Phase Cascade Multilevel Inverter Using a Single DC Source for a PM Synchronous Motor Drive

    SciTech Connect

    Ozpineci, Burak; Chiasson, John N; Tolbert, Leon M

    2007-01-01

    The interest here is in using a single DC power source to construct a 3-phase 5-level cascade multilevel inverter to be used as a drive for a PM traction motor. The 5-level inverter consists of a standard 3-leg inverter (one leg for each phase) and an H-bridge in series with each inverter leg, which use a capacitor as a DC source. It is shown that one can simultaneously maintain the regulation of the capacitor voltage while achieving an output voltage waveform which is 25% higher than that obtained using a standard 3-leg inverter by itself.

  14. 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.

  15. 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.

  16. 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.

  17. Automated setup for magnetic hysteresis characterization based on a voltage controlled current source with 500 kHz full power bandwidth and 10 A peak-to-peak current

    SciTech Connect

    Calabrese, G.; Capineri, L.; Granato, M.; Frattini, G.

    2015-04-15

    This paper describes the design of a system for the characterization of magnetic hysteresis behavior in soft ferrite magnetic cores. The proposed setup can test magnetic materials exciting them with controlled arbitrary magnetic field waveforms, including the capability of providing a DC bias, in a frequency bandwidth up to 500 kHz, with voltages up to 32 V peak-to-peak, and currents up to 10 A peak-to-peak. In order to have an accurate control of the magnetic field waveform, the system is based on a voltage controlled current source. The electronic design is described focusing on closed loop feedback stabilization and passive components choice. The system has real-time hysteretic loop acquisition and visualization. The comparisons between measured hysteresis loops of sample magnetic materials and datasheet available ones are shown. Results showing frequency and thermal behavior of the hysteresis of a test sample prove the system capabilities. Moreover, the B-H loops obtained with a multiple waveforms excitation signal, including DC bias, are reported. The proposal is a low-cost and replicable solution for hysteresis characterization of magnetic materials used in power electronics.

  18. Automated setup for magnetic hysteresis characterization based on a voltage controlled current source with 500 kHz full power bandwidth and 10 A peak-to-peak current.

    PubMed

    Calabrese, G; Capineri, L; Granato, M; Frattini, G

    2015-04-01

    This paper describes the design of a system for the characterization of magnetic hysteresis behavior in soft ferrite magnetic cores. The proposed setup can test magnetic materials exciting them with controlled arbitrary magnetic field waveforms, including the capability of providing a DC bias, in a frequency bandwidth up to 500 kHz, with voltages up to 32 V peak-to-peak, and currents up to 10 A peak-to-peak. In order to have an accurate control of the magnetic field waveform, the system is based on a voltage controlled current source. The electronic design is described focusing on closed loop feedback stabilization and passive components choice. The system has real-time hysteretic loop acquisition and visualization. The comparisons between measured hysteresis loops of sample magnetic materials and datasheet available ones are shown. Results showing frequency and thermal behavior of the hysteresis of a test sample prove the system capabilities. Moreover, the B-H loops obtained with a multiple waveforms excitation signal, including DC bias, are reported. The proposal is a low-cost and replicable solution for hysteresis characterization of magnetic materials used in power electronics.

  19. 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.

  20. 46 CFR 183.324 - Dual voltage generators.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Dual voltage generators. 183.324 Section 183.324... TONS) ELECTRICAL INSTALLATION Power Sources and Distribution Systems § 183.324 Dual voltage generators. (a) A dual voltage generator installed on a vessel shall be of the grounded type, where: (1)...

  1. 46 CFR 120.324 - Dual voltage generators.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Dual voltage generators. 120.324 Section 120.324... INSTALLATION Power Sources and Distribution Systems § 120.324 Dual voltage generators. (a) A dual voltage generator installed on a vessel shall be of the grounded type, where: (1) The neutral of a dual...

  2. 46 CFR 183.324 - Dual voltage generators.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Dual voltage generators. 183.324 Section 183.324... TONS) ELECTRICAL INSTALLATION Power Sources and Distribution Systems § 183.324 Dual voltage generators. (a) A dual voltage generator installed on a vessel shall be of the grounded type, where: (1)...

  3. 46 CFR 183.324 - Dual voltage generators.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Dual voltage generators. 183.324 Section 183.324... TONS) ELECTRICAL INSTALLATION Power Sources and Distribution Systems § 183.324 Dual voltage generators. (a) A dual voltage generator installed on a vessel shall be of the grounded type, where: (1)...

  4. 46 CFR 120.324 - Dual voltage generators.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Dual voltage generators. 120.324 Section 120.324... INSTALLATION Power Sources and Distribution Systems § 120.324 Dual voltage generators. (a) A dual voltage generator installed on a vessel shall be of the grounded type, where: (1) The neutral of a dual...

  5. 46 CFR 183.324 - Dual voltage generators.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Dual voltage generators. 183.324 Section 183.324... TONS) ELECTRICAL INSTALLATION Power Sources and Distribution Systems § 183.324 Dual voltage generators. (a) A dual voltage generator installed on a vessel shall be of the grounded type, where: (1)...

  6. 46 CFR 120.324 - Dual voltage generators.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Dual voltage generators. 120.324 Section 120.324... INSTALLATION Power Sources and Distribution Systems § 120.324 Dual voltage generators. (a) A dual voltage generator installed on a vessel shall be of the grounded type, where: (1) The neutral of a dual...

  7. 46 CFR 120.324 - Dual voltage generators.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Dual voltage generators. 120.324 Section 120.324... INSTALLATION Power Sources and Distribution Systems § 120.324 Dual voltage generators. (a) A dual voltage generator installed on a vessel shall be of the grounded type, where: (1) The neutral of a dual...

  8. 46 CFR 183.324 - Dual voltage generators.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Dual voltage generators. 183.324 Section 183.324... TONS) ELECTRICAL INSTALLATION Power Sources and Distribution Systems § 183.324 Dual voltage generators. (a) A dual voltage generator installed on a vessel shall be of the grounded type, where: (1)...

  9. 46 CFR 120.324 - Dual voltage generators.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Dual voltage generators. 120.324 Section 120.324... INSTALLATION Power Sources and Distribution Systems § 120.324 Dual voltage generators. (a) A dual voltage generator installed on a vessel shall be of the grounded type, where: (1) The neutral of a dual...

  10. High voltage supply for neutron tubes in well logging applications

    DOEpatents

    Humphreys, D. Russell

    1989-01-01

    A high voltage supply is provided for a neutron tube used in well logging. The "biased pulse" supply of the invention combines DC and "full pulse" techniques and produces a target voltage comprising a substantial negative DC bias component on which is superimposed a pulse whose negative peak provides the desired negative voltage level for the neutron tube. The target voltage is preferably generated using voltage doubling techniques and employing a voltage source which generates bipolar pulse pairs having an amplitude corresponding to the DC bias level.

  11. A Matching Transformer-less Inrush Current Suppressor for Transformers Using a Series-Connected Small-Rated Voltage-Source PWM Converter

    NASA Astrophysics Data System (ADS)

    Yamada, Hiroaki; Tanaka, Toshihiko; Funabiki, Shigeyuki

    This paper proposes a new inrush current suppressor using a series-connected small-rated PWM converter for a transformer. The PWM converter is directly connected in series between the source and transformer without a matching transformer. The inrush phenomena of the matching transformer, thus, can be avoided. The control gain and required-ratings of the series-connected small-rated PWM converter is discussed in detail. The capacity of the dc capacitor of the PWM converter is also discussed considering the active power flows into the PWM converter. The PSCAD/EMTDC is used to verify the validity of the proposed inrush current suppressor. A prototype experimental model is constructed and tested. The experimental results demonstrate that the proposed suppressor can perfectly overcome the inrush phenomena of transformers.

  12. Voltage controlled spintronic devices for logic applications

    DOEpatents

    You, Chun-Yeol; Bader, Samuel D.

    2001-01-01

    A reprogrammable logic gate comprising first and second voltage-controlled rotation transistors. Each transistor comprises three ferromagnetic layers with a spacer and insulating layer between the first and second ferromagnetic layers and an additional insulating layer between the second and third ferromagnetic layers. The third ferromagnetic layer of each transistor is connected to each other, and a constant external voltage source is applied to the second ferromagnetic layer of the first transistor. As input voltages are applied to the first ferromagnetic layer of each transistor, the relative directions of magnetization of the ferromagnetic layers and the magnitude of the external voltage determines the output voltage of the gate. By altering these parameters, the logic gate is capable of behaving as AND, OR, NAND, or NOR gates.

  13. The LMF triaxial MITL voltage adder system

    SciTech Connect

    Mazarakis, M.G.; Smith, D.L.; Bennett, L.F.; Lockner, T.R.; Olson, R.E.; Poukey, J.W.

    1992-12-31

    The light-ion microfusion driver design consists of multiple accelerating modules fired in coincidence and sequentially in order to provide the desired ion energy, power pulse shape and energy deposition uniformity on an Inertial Confinement Fusion (ICF) target. The basic energy source is a number of Marx generators which, through the appropriate pulse power conditioning, provide the necessary voltage pulse wave form to the accelerating gaps or feeds of each module. The cavity gaps are inductively isolated, and the voltage addition occurs in the center conductor of the voltage adder which is the positive electrode while the electrons of the sheath flow closer to the outer cylinder which is the magnetically insulated cathode electrode. Each module powers a separate two-stage extraction diode which provides a low divergence ion beam. In order to provide the two separate voltage pulses required by the diode, a triaxial adder system is designed for each module. The voltage addition occurs in two separate MITLs. The center hollow cylinder (anode) of the second MITL also serves as the outer cathode electrode for the extension of the first voltage adder MITL. The voltage of the second stage is about twice that of the first stage. The cavities are connected in series to form the outer cylinder of each module. The accelerating modules are positioned radially in a symmetrical way around the fusion chamber. A preliminary conceptual design of the LMF modules with emphasis on the voltage adders and extension MITLs will be presented and discussed.

  14. High voltage photovoltaic power converter

    DOEpatents

    Haigh, Ronald E.; Wojtczuk, Steve; Jacobson, Gerard F.; Hagans, Karla G.

    2001-01-01

    An array of independently connected photovoltaic cells on a semi-insulating substrate contains reflective coatings between the cells to enhance efficiency. A uniform, flat top laser beam profile is illuminated upon the array to produce electrical current having high voltage. An essentially wireless system includes a laser energy source being fed through optic fiber and cast upon the photovoltaic cell array to prevent stray electrical signals prior to use of the current from the array. Direct bandgap, single crystal semiconductor materials, such as GaAs, are commonly used in the array. Useful applications of the system include locations where high voltages are provided to confined spaces such as in explosive detonation, accelerators, photo cathodes and medical appliances.

  15. 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.

  16. 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.

  17. 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%.

  18. 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.

  19. 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

  20. Electro-optic high voltage sensor

    DOEpatents

    Davidson, James R.; Seifert, Gary D.

    2003-09-16

    A small sized electro-optic voltage sensor capable of accurate measurement of high voltages without contact with a conductor or voltage source is provided. When placed in the presence of an electric field, the sensor receives an input beam of electromagnetic radiation. A polarization beam displacer separates the input beam into two beams with orthogonal linear polarizations and causes one linearly polarized beam to impinge a crystal at a desired angle independent of temperature. The Pockels effect elliptically polarizes the beam as it travels through the crystal. A reflector redirects the beam back through the crystal and the beam displacer. On the return path, the polarization beam displacer separates the elliptically polarized beam into two output beams of orthogonal linear polarization. The system may include a detector for converting the output beams into electrical signals and a signal processor for determining the voltage based on an analysis of the output beams.

  1. Low voltage arc formation in railguns

    DOEpatents

    Hawke, R.S.

    1985-08-05

    A low voltage plasma arc is first established across the rails behind the projectile by switching a low voltage high current source across the rails to establish a plasma arc by vaporizing a fuse mounted on the back of the projectile, maintaining the voltage across the rails below the railgun breakdown voltage to prevent arc formation ahead of the projectile. After the plasma arc has been formed behind the projectile a discriminator switches the full energy bank across the rails to accelerate the projectile. A gas gun injector may be utilized to inject a projectile into the breech of a railgun. The invention permits the use of a gas gun or gun powder injector and an evacuated barrel without the risk of spurious arc formation in front of the projectile.

  2. Low voltage arc formation in railguns

    DOEpatents

    Hawke, R.S.

    1987-11-17

    A low voltage plasma arc is first established across the rails behind the projectile by switching a low voltage high current source across the rails to establish a plasma arc by vaporizing a fuse mounted on the back of the projectile, maintaining the voltage across the rails below the railgun breakdown voltage to prevent arc formation ahead of the projectile. After the plasma arc has been formed behind the projectile a discriminator switches the full energy bank across the rails to accelerate the projectile. A gas gun injector may be utilized to inject a projectile into the breech of a railgun. The invention permits the use of a gas gun or gun powder injector and an evacuated barrel without the risk of spurious arc formation in front of the projectile. 2 figs.

  3. Low voltage arc formation in railguns

    DOEpatents

    Hawke, Ronald S.

    1987-01-01

    A low voltage plasma arc is first established across the rails behind the projectile by switching a low voltage high current source across the rails to establish a plasma arc by vaporizing a fuse mounted on the back of the projectile, maintaining the voltage across the rails below the railgun breakdown voltage to prevent arc formation ahead of the projectile. After the plasma arc has been formed behind the projectile a discriminator switches the full energy bank across the rails to accelerate the projectile. A gas gun injector may be utilized to inject a projectile into the breech of a railgun. The invention permits the use of a gas gun or gun powder injector and an evacuated barrel without the risk of spurious arc formation in front of the projectile.

  4. 30 CFR 75.812-2 - High-voltage power centers and transformers; record of examination.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false High-voltage power centers and transformers... High-Voltage Distribution § 75.812-2 High-voltage power centers and transformers; record of examination... record shall be kept in a book approved by the Secretary. High-Voltage Longwalls Source: 67 FR 11001,...

  5. 30 CFR 75.812-2 - High-voltage power centers and transformers; record of examination.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false High-voltage power centers and transformers... High-Voltage Distribution § 75.812-2 High-voltage power centers and transformers; record of examination... record shall be kept in a book approved by the Secretary. High-Voltage Longwalls Source: 67 FR 11001,...

  6. 30 CFR 75.812-2 - High-voltage power centers and transformers; record of examination.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false High-voltage power centers and transformers... High-Voltage Distribution § 75.812-2 High-voltage power centers and transformers; record of examination... record shall be kept in a book approved by the Secretary. High-Voltage Longwalls Source: 67 FR 11001,...

  7. 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.

  8. Voltage-current-power meter for photovoltaic solar arrays

    NASA Technical Reports Server (NTRS)

    Ross, Ronald G. (Inventor)

    1979-01-01

    A meter is disclosed for measuring the voltage, current, and power (VIP) parameters of a photovoltaic solar array, or array module, under sunlight operating conditions utilizing a variable load connected across the array and controlled by a voltage regulator which responds to the difference between the output voltage of the array and a programmed test voltage from a source which generates a single ramp voltage for measuring and recording current as a function of voltage, repeated ramp voltages at a high rate for peak output measurements or a DC voltage for VIP measurements at selected points on the I-V characteristic curve of the array. The voltage signal from a current sensing element, such as a shunt resistor in series with the variable load, is compared with the output current of a reference solar cell to provide a normalizing signal to be added to the signal from the current-sensing element in order to provide a record of array current as a function of array voltage, i.e., for all load conditions from short circuit to open circuit. As the normalized current is thus measured, an analog multiplier multiplies the array voltage and normalized current to provide a measurement of power. Switches are provided to selectively connect the power, P, current, I, or voltage, V, to a meter, directly or through a peak detector. At the same time any one of the parameters V, I and P may be recorded as a function of any other parameter.

  9. 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.

  10. Fuel injection pump having voltage variation compensation

    SciTech Connect

    Takemoto, E.; Miyaki, M.; Norimatsu, H.; Hobo, N.; Tsuzuki, Y.; Konishi, Y.

    1986-08-05

    A fuel injection pump is described for internal combustion engine, comprising: an enclosure; pump means including a plunger rotatingly and reciprocally movable in the enclosure to define a compression chamber of variable volume, the pump means coupling the compression chamber to a fuel inlet during an intake stroke of the plunger and connecting the compression chamber to a fuel outlet during a compression stroke of the plunger to thereby initiate injection of fuel to the outlet, the pump means being responsive to the speed of rotation of the engine to pressurize the fuel in the inlet; means for detecting the speed of the engine; a source of voltage having a tendency to vary; solenoid valve means operable when a voltage is applied thereto from the source for providing a pressure relief action of the fuel in the compression chamber to terminate the injection of fuel; a memory storing trimming data in locations addressable as a function of the detected voltage and as a function of the detected engine speed; and control means for detecting the voltage of the source and responsive to the initiation of the fuel injection for determining the basic timing at which the fuel injection is to be terminated, reading trimming data out of the memory as a function of the detected voltage and as a function of the detected engine speed, correcting the basic timing in accordance with the trimming data and applying the voltage of the source to the solenoid valve means at the corrected timing to thereby terminate the fuel injection.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Power conditioning system for energy sources

    DOEpatents

    Mazumder, Sudip K.; Burra, Rajni K.; Acharya, Kaustuva

    2008-05-13

    Apparatus for conditioning power generated by an energy source includes an inverter for converting a DC input voltage from the energy source to a square wave AC output voltage, and a converter for converting the AC output voltage from the inverter to a sine wave AC output voltage.

  16. Voltage-Dependent Gating of hERG Potassium Channels

    PubMed Central

    Cheng, Yen May; Claydon, Tom W.

    2012-01-01

    The mechanisms by which voltage-gated channels sense changes in membrane voltage and energetically couple this with opening of the ion conducting pore has been the source of significant interest. In voltage-gated potassium (Kv) channels, much of our knowledge in this area comes from Shaker-type channels, for which voltage-dependent gating is quite rapid. In these channels, activation and deactivation are associated with rapid reconfiguration of the voltage-sensing domain unit that is electromechanically coupled, via the S4–S5 linker helix, to the rate-limiting opening of an intracellular pore gate. However, fast voltage-dependent gating kinetics are not typical of all Kv channels, such as Kv11.1 (human ether-à-go-go related gene, hERG), which activates and deactivates very slowly. Compared to Shaker channels, our understanding of the mechanisms underlying slow hERG gating is much poorer. Here, we present a comparative review of the structure–function relationships underlying activation and deactivation gating in Shaker and hERG channels, with a focus on the roles of the voltage-sensing domain and the S4–S5 linker that couples voltage sensor movements to the pore. Measurements of gating current kinetics and fluorimetric analysis of voltage sensor movement are consistent with models suggesting that the hERG activation pathway contains a voltage independent step, which limits voltage sensor transitions. Constraints upon hERG voltage sensor movement may result from loose packing of the S4 helices and additional intra-voltage sensor counter-charge interactions. More recent data suggest that key amino acid differences in the hERG voltage-sensing unit and S4–S5 linker, relative to fast activating Shaker-type Kv channels, may also contribute to the increased stability of the resting state of the voltage sensor. PMID:22586397

  17. 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.

  18. 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.

  19. 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…

  20. 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)

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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).

  11. Voltage Control in Distribution Systems Considered Reactive Power Output Sharing

    NASA Astrophysics Data System (ADS)

    Oshiro, Masato; Senjyu, Tomonobu; Yona, Atsushi; Urasaki, Naomitsu; Funabashi, Toshihisa

    In recent years, distributed generation (DG) and renewable energy source (RES) are attracting special attention to distribution systems. Renewable energy such as photovoltaic (PV) system and wind turbine generator are used as a source of clean energy. However, the large amount of distributed generation causes voltage deviation beyond a statutory range in distribution systems. This paper proposes a methodology for voltage control by using inverters interfaced with DG and tap changing transformers. In the proposed method a one-day schedule of voltage references for the control devices are determined by an optimization technique based on predicted values of load demand and PV power generation. Furthermore, decided reactive power output according to the locally measurable voltage based on droop characteristic. Slope and base value on droop characteristic are selected by fuzzy control. The proposed method accomplishes improvement against voltage distribution considered the reactive power output sharing and reduction of distribution loss. The effectiveness of the proposed method is verified by using MATLAB®.

  12. Lyotropic liquid crystalline L3 phase silicated nanoporous monolithic composites and their production

    DOEpatents

    McGrath, Kathryn M.; Dabbs, Daniel M.; Aksay, Ilhan A.; Gruner, Sol M.

    2003-10-28

    A mesoporous ceramic material is provided having a pore size diameter in the range of about 10-100 nanometers produced by templating with a ceramic precursor a lyotropic liquid crystalline L.sub.3 phase consisting of a three-dimensional, random, nonperiodic network packing of a multiple connected continuous membrane. A preferred process for producing the inesoporous ceramic material includes producing a template of a lyotropic liquid crystalline L.sub.3 phase by mixing a surfactant, a co-surfactant and hydrochloric acid, coating the template with an inorganic ceramic precursor by adding to the L.sub.3 phase tetramethoxysilane (TMOS) or tetraethoxysilane (TEOS) and then converting the coated template to a ceramic by removing any remaining liquids.

  13. Electrical system architecture having high voltage bus

    DOEpatents

    Hoff, Brian Douglas; Akasam, Sivaprasad

    2011-03-22

    An electrical system architecture is disclosed. The architecture has a power source configured to generate a first power, and a first bus configured to receive the first power from the power source. The architecture also has a converter configured to receive the first power from the first bus and convert the first power to a second power, wherein a voltage of the second power is greater than a voltage of the first power, and a second bus configured to receive the second power from the converter. The architecture further has a power storage device configured to receive the second power from the second bus and deliver the second power to the second bus, a propulsion motor configured to receive the second power from the second bus, and an accessory motor configured to receive the second power from the second bus.

  14. Triple voltage dc-to-dc converter and method

    SciTech Connect

    Su, Gui-Jia

    2008-08-05

    A circuit and method of providing three dc voltage buses and transforming power between a low voltage dc converter and a high voltage dc converter, by coupling a primary dc power circuit and a secondary dc power circuit through an isolation transformer; providing the gating signals to power semiconductor switches in the primary and secondary circuits to control power flow between the primary and secondary circuits and by controlling a phase shift between the primary voltage and the secondary voltage. The primary dc power circuit and the secondary dc power circuit each further comprising at least two tank capacitances arranged in series as a tank leg, at least two resonant switching devices arranged in series with each other and arranged in parallel with the tank leg, and at least one voltage source arranged in parallel with the tank leg and the resonant switching devices, said resonant switching devices including power semiconductor switches that are operated by gating signals. Additional embodiments having a center-tapped battery on the low voltage side and a plurality of modules on both the low voltage side and the high voltage side are also disclosed for the purpose of reducing ripple current and for reducing the size of the components.

  15. High-voltage supply for neutron tubes in well-logging applications

    DOEpatents

    Humphreys, D.R.

    1982-09-15

    A high voltage supply is provided for a neutron tube used in well logging. The biased pulse supply of the invention combines DC and full pulse techniques and produces a target voltage comprising a substantial negative DC bias component on which is superimposed a pulse whose negative peak provides the desired negative voltage level for the neutron tube. The target voltage is preferably generated using voltage doubling techniques and employing a voltage source which generates bipolar pulse pairs having an amplitude corresponding to the DC bias level.

  16. SEMICONDUCTOR DEVICES: A novel high voltage start up circuit for an integrated switched mode power supply

    NASA Astrophysics Data System (ADS)

    Hao, Hu; Xingbi, Chen

    2010-09-01

    A novel high voltage start up circuit for providing an initial bias voltage to an integrated switched mode power supply (SMPS) is presented. An enhanced mode VDMOS transistor, the gate of which is biased by a floating p-island, is used to provide start up current and sustain high voltage. An NMOS transistor having a high source to ground breakdown voltage is included to extend the bias voltage range to the SMPS. Simulation results indicate that the high voltage start up circuit can start and restart as designed. The proposed structure is believed to be more energy saving and cost-effective compared with other solutions.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. High voltage solar cell power generating system

    NASA Technical Reports Server (NTRS)

    Levy, E., Jr.; Opjorden, R. W.; Hoffman, A. C.

    1974-01-01

    A laboratory solar power system regulated by on-panel switches has been delivered for operating high power (3 kW), high voltage (15,000 volt) loads (communication tubes, ion thrusters). The modular system consists of 26 solar arrays, each with an integral light source and cooling system. A typical array contains 2,560 series-connected cells. Each light source consists of twenty 500-watt tungsten iodide lamps providing plus or minus 5 percent uniformity at one solar constant. An array temperature of less than 40 C is achieved using an infrared filter, a water-cooled plate, a vacuum hold-down system, and air flushing.

  2. Development of a fast voltage control method for electrostatic accelerators

    NASA Astrophysics Data System (ADS)

    Lobanov, Nikolai R.; Linardakis, Peter; Tsifakis, Dimitrios

    2014-12-01

    The concept of a novel fast voltage control loop for tandem electrostatic accelerators is described. This control loop utilises high-frequency components of the ion beam current intercepted by the image slits to generate a correction voltage that is applied to the first few gaps of the low- and high-energy acceleration tubes adjoining the high voltage terminal. New techniques for the direct measurement of the transfer function of an ultra-high impedance structure, such as an electrostatic accelerator, have been developed. For the first time, the transfer function for the fast feedback loop has been measured directly. Slow voltage variations are stabilised with common corona control loop and the relationship between transfer functions for the slow and new fast control loops required for optimum operation is discussed. The main source of terminal voltage instabilities, which are due to variation of the charging current caused by mechanical oscillations of charging chains, has been analysed.

  3. Source circuit design considerations

    NASA Technical Reports Server (NTRS)

    Noel, G. T.

    1983-01-01

    The cost of several circuit configurations for large (5MW) array fields were investigated to assess the relative costs of high and low voltage configurations. Three source circuit NOC voltages were evaluated: 400V (ungrounded), 800V (+ or 400V center grounded), and 2000V (+ or - 1000V center grounded). Four source circuit configurations were considered for each of the three NOC voltages. The configurations correspond to source circuit currents of 15, 30, 45, and 60 amperes, respectively. Conceptual layouts for 5MW building blocks for each of the above configurations were developed. The designs were optimized to minimize BOS electrical and structural costs. Only the BOS electrical costs were evaluated. The designs were broken down into the following elements for cost: (1) basic source circuit intermodule wiring, bypass diodes and associated hardware, source circuit to J-Box wiring, etc; (2) J-Box blocking diodes, varistors, heat sinks, and housing; (3) disconnects source circuit disconnects, fuses, and housing; (4) bus cabling J-Box to PCU interface wiring, and trenching; (5) interface bus bar, group disconnects, and fuses; and (6) fault detection shunts, signal wire, electronics, and alarm. It is concluded that high voltage low current circuits are not economical, at higher currents high and low voltage circuit costs approach each other, high voltage circuits are not likely to offer near term advantage, and development work/manufacturer stimulation is needed to develop low cost high voltage hardware.

  4. 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.

  5. Electro-optic high voltage sensor

    DOEpatents

    Davidson, James R.; Seifert, Gary D.

    2002-01-01

    A small sized electro-optic voltage sensor capable of accurate measurement of high levels of voltages without contact with a conductor or voltage source is provided. When placed in the presence of an electric field, the sensor receives an input beam of electromagnetic radiation into the sensor. A polarization beam displacer serves as a filter to separate the input beam into two beams with orthogonal linear polarizations. The beam displacer is oriented in such a way as to rotate the linearly polarized beams such that they enter a Pockels crystal having at a preferred angle of 45 degrees. The beam displacer is therefore capable of causing a linearly polarized beam to impinge a crystal at a desired angle independent of temperature. The Pockels electro-optic effect induces a differential phase shift on the major and minor axes of the input beam as it travels through the Pockels crystal, which causes the input beam to be elliptically polarized. A reflecting prism redirects the beam back through the crystal and the beam displacer. On the return path, the polarization beam displacer separates the elliptically polarized beam into two output beams of orthogonal linear polarization representing the major and minor axes. The system may include a detector for converting the output beams into electrical signals, and a signal processor for determining the voltage based on an analysis of the output beams. The output beams are amplitude modulated by the frequency of the electric field and the amplitude of the output beams is proportional to the magnitude of the electric field, which is related to the voltage being measured.

  6. Dynamics of laser-guided alternating current high voltage discharges

    NASA Astrophysics Data System (ADS)

    Daigle, J.-F.; Théberge, F.; Lassonde, P.; Kieffer, J.-C.; Fujii, T.; Fortin, J.; Châteauneuf, M.; Dubois, J.

    2013-10-01

    The dynamics of laser-guided alternating current high voltage discharges are characterized using a streak camera. Laser filaments were used to trigger and guide the discharges produced by a commercial Tesla coil. The streaking images revealed that the dynamics of the guided alternating current high voltage corona are different from that of a direct current source. The measured effective corona velocity and the absence of leader streamers confirmed that it evolves in a pure leader regime.

  7. 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.

  8. 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.

  9. 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.

  10. PV String to 3-Phase Inverter with Highest Voltage Capabilities, Highest Efficiency and 25 Year Lifetime: Final Technical Report, November 7, 2011 - November 6, 2012

    SciTech Connect

    West, R.

    2012-12-01

    Final report for Renewable Power Conversion. The overall objective of this project was to develop a prototype PV inverter which enables a new utility-scale PV system approach where the cost, performance, reliability and safety benefits of this new approach have the potential to make all others obsolete.

  11. Subthreshold voltage noise of rat neocortical pyramidal neurones.

    PubMed

    Jacobson, Gilad A; Diba, Kamran; Yaron-Jakoubovitch, Anat; Oz, Yasmin; Koch, Christof; Segev, Idan; Yarom, Yosef

    2005-04-01

    Neurones are noisy elements. Noise arises from both intrinsic and extrinsic sources, and manifests itself as fluctuations in the membrane potential. These fluctuations limit the accuracy of a neurone's output but have also been suggested to play a computational role. We present a detailed study of the amplitude and spectrum of voltage noise recorded at the soma of layer IV-V pyramidal neurones in slices taken from rat neocortex. The dependence of the noise on holding potential, synaptic activity and Na+ conductance is systematically analysed. We demonstrate that voltage noise increases non-linearly as the cell depolarizes (from a standard deviation (s.d.) of 0.19 mV at -75 mV to an s.d. of 0.54 mV at -55 mV). The increase in voltage noise is accompanied by an increase in the cell impedance, due to voltage dependence of Na+ conductance. The impedance increase accounts for the majority (70%) of the voltage noise increase. The increase in voltage noise and impedance is restricted to the low-frequency range (0.2-2 Hz). At the high frequency range (5-100 Hz) the voltage noise is dominated by synaptic activity. In our slice preparation, synaptic noise has little effect on the cell impedance. A minimal model reproduces qualitatively these data. Our results imply that ion channel noise contributes significantly to membrane voltage fluctuations at the subthreshold voltage range, and that Na+ conductance plays a key role in determining the amplitude of this noise by acting as a voltage-dependent amplifier of low-frequency transients. PMID:15695244

  12. Subthreshold voltage noise of rat neocortical pyramidal neurones

    PubMed Central

    Jacobson, Gilad A; Diba, Kamran; Yaron-Jakoubovitch, Anat; Oz, Yasmin; Koch, Christof; Segev, Idan; Yarom, Yosef

    2005-01-01

    Neurones are noisy elements. Noise arises from both intrinsic and extrinsic sources, and manifests itself as fluctuations in the membrane potential. These fluctuations limit the accuracy of a neurone's output but have also been suggested to play a computational role. We present a detailed study of the amplitude and spectrum of voltage noise recorded at the soma of layer IV–V pyramidal neurones in slices taken from rat neocortex. The dependence of the noise on holding potential, synaptic activity and Na+ conductance is systematically analysed. We demonstrate that voltage noise increases non-linearly as the cell depolarizes (from a standard deviation (s.d.) of 0.19 mV at −75 mV to an s.d. of 0.54 mV at −55 mV). The increase in voltage noise is accompanied by an increase in the cell impedance, due to voltage dependence of Na+ conductance. The impedance increase accounts for the majority (70%) of the voltage noise increase. The increase in voltage noise and impedance is restricted to the low-frequency range (0.2–2 Hz). At the high frequency range (5–100 Hz) the voltage noise is dominated by synaptic activity. In our slice preparation, synaptic noise has little effect on the cell impedance. A minimal model reproduces qualitatively these data. Our results imply that ion channel noise contributes significantly to membrane voltage fluctuations at the subthreshold voltage range, and that Na+ conductance plays a key role in determining the amplitude of this noise by acting as a voltage-dependent amplifier of low-frequency transients. PMID:15695244

  13. 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.

  14. 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.

  15. 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.

  16. Synthesis of Dense BC3 Phases under High-Pressure and High-Temperature

    NASA Astrophysics Data System (ADS)

    Zinin, P.; Ming, L.; Acosta, T.; Jia, R.; Hellebrand, E.; Ishii, H.

    2010-12-01

    The finding of the new diamond-like B-C phases is of fundamental importance. These phases are potential high-temperature superconductors and their development is important for understanding the nature of high-temperature superconductivity (Moussa, Cohen, Phys. Rev. B, 77, 064518 2008). They will shed light on the nature of the bonding of the boron atoms in a diamond-like structure. Recently, theoretical simulations of pressure- and temperature-induced phase transition in the B-C system demonstrated that the incorporation of B atoms into a diamond structure should not lead to a drastic distortion of the cubic cell of a diamond (Lowther, J. Phys. Condense Matter. 17, 3221, 2005). In this report we present data on the synthesis of new dense phases cubic BC3 (c-BC3) phase from graphitic BC3 phase (g-BC3) phase under high pressure and high temperature. Two graphitic polycrystalline BCx samples were compressed in a diamond-anvil cell to about 24 GPa and 45 GPa, respectively, and then were laser-heated to ~2000 K. After quenching, each sample was decompressed gradually stepwise to the atmospheric pressure. Synchrotron-based X-ray diffraction patterns were taken before and after the laser-heating, and also at each pressure step-down. The experimental data showed that two new phases were synthesized: (a) an orthorhombic phase with a0 = 3.74 Å, b0 = 3.24 Å, c0=4.25 Å; and (b) a cubic phase with a0 = 3.587Å recovered from 24 GPa and 44 GPa, respectively. The zero-pressure lattice parameter of the cubic phase obtained in this study is larger than that of diamond (i.e., a0=3.5667 Å, ASTM # 6-0675), which is consistent with theoretical prediction The micro-Raman measurements were directly performed on the new phases. The Raman spectra excited by a green (Nd-YAG, 532-nm) laser were taken with a confocal Raman system (WiTec alpha300). The Raman spectrum of the c-BC3 phase is similar to that of diamond-like BC3 phase (Zinin et al., J. Raman Spectrosc., 38, 1362, 2007) with a

  17. 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.

  18. Low input voltage switching amplifiers for piezoelectric actuators

    NASA Astrophysics Data System (ADS)

    Lindner, Douglas K.; Zhu, Huiyu; Song, Chunping; Huang, Weixing; Cheng, Danling

    2002-07-01

    The Inertially Stabilized Rifle is a new stabilized rifle system that can eliminate the disturbances induced by the shooter. Recurve actuator is used in this system to provide the precise movement of the rifle barrel. In such a portable device, only low voltage electrical sources are available yet the piezoelectric actuator needs high voltage to drive the actuator. The actuators consume little real power but a large amount of reactive power. Furthermore, the piezoelectric actuators are present an almost purely capacitive load. In this paper, we describe the development of a low input voltage amplifier for a high voltage piezoelectric actuator. This amplifier is based on switching technology so it efficiently handles the regenerative energy from the piezoelectric actuator. This amplifier consists of two stages. The first stage is a flyback converter which boosts the (low) input voltage to the maximum voltage required by the piezoelectric actuator. The second stage is a half-bridge amplifier which delivers the output voltage to the actuator as commanded by the reference signal. The basic structure of the amplifier is described, and its performance is characterized in terms of bandwidth, distortion, and efficiency.

  19. Genetically Engineered Fluorescent Voltage Reporters

    PubMed Central

    2012-01-01

    Fluorescent membrane voltage indicators that enable optical imaging of neuronal circuit operations in the living mammalian brain are powerful tools for biology and particularly neuroscience. Classical voltage-sensitive dyes, typically low molecular-weight organic compounds, have been in widespread use for decades but are limited by issues related to optical noise, the lack of generally applicable procedures that enable staining of specific cell populations, and difficulties in performing imaging experiments over days and weeks. Genetically encoded voltage indicators (GEVIs) represent a newer alternative that overcomes several of the limitations inherent to classical voltage-sensitive dyes. We critically review the fundamental concepts of this approach, the variety of available probes and their state of development. PMID:22896802

  20. Low-Voltage Bypass Device

    NASA Technical Reports Server (NTRS)

    Wilson, J. P.

    1994-01-01

    Improved bypass device provides low-resistance current shunt around low-voltage power cell when cell fails in open-circuit condition during operation. In comparison with older bypass devices for same application, this one weighs less, generates less heat, and has lower voltage drop (less resistance). Bypass device connected in parallel with power cell. Draws very little current during normal operation of cell.

  1. Switched-Capacitor Voltage Multiplier

    NASA Technical Reports Server (NTRS)

    Sridharan, Govind

    1991-01-01

    Dc-to-dc power converter multiplies input supply potential by factor of nearly 40. Design does not make use of transformers or inductors but effects voltage boost-up by capacitive energy transfer. Circuit primarily made up of banks of capacitors, connected by network of integrated-circuit relays. Converter functionally linear voltage amplifier with fixed gain figure. Bipolar in operation. Output fully floating, and excellent dc isolation between input and output terminals.

  2. High voltage power transistor development

    NASA Technical Reports Server (NTRS)

    Hower, P. L.

    1981-01-01

    Design considerations, fabrication procedures, and methods of evaluation for high-voltage power-transistor development are discussed. Technique improvements such as controlling the electric field at the surface and perserving lifetimes in the collector region which have advanced the state of the art in high-voltage transistors are discussed. These improvements can be applied directly to the development of 1200 volt, 200 ampere transistors.

  3. A matter of quantum voltages.

    PubMed

    Sellner, Bernhard; Kathmann, Shawn M

    2014-11-14

    Voltages inside matter are relevant to crystallization, materials science, biology, catalysis, and aqueous chemistry. The variation of voltages in matter can be measured by experiment, however, modern supercomputers allow the calculation of accurate quantum voltages with spatial resolutions of bulk systems well beyond what can currently be measured provided a sufficient level of theory is employed. Of particular interest is the Mean Inner Potential (V(o))--the spatial average of these quantum voltages referenced to the vacuum. Here we establish a protocol to reliably evaluate V(o) from quantum calculations. 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 V(o) for vitrified water and salt crystals and demonstrate the impact of covalent and ionic bonding as well as intermolecular/atomic interactions. Certain aspects in this regard are highlighted making use of simple model systems/approximations. Furthermore, we predict V(o) 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. PMID:25399199

  4. A matter of quantum voltages.

    PubMed

    Sellner, Bernhard; Kathmann, Shawn M

    2014-11-14

    Voltages inside matter are relevant to crystallization, materials science, biology, catalysis, and aqueous chemistry. The variation of voltages in matter can be measured by experiment, however, modern supercomputers allow the calculation of accurate quantum voltages with spatial resolutions of bulk systems well beyond what can currently be measured provided a sufficient level of theory is employed. Of particular interest is the Mean Inner Potential (V(o))--the spatial average of these quantum voltages referenced to the vacuum. Here we establish a protocol to reliably evaluate V(o) from quantum calculations. 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 V(o) for vitrified water and salt crystals and demonstrate the impact of covalent and ionic bonding as well as intermolecular/atomic interactions. Certain aspects in this regard are highlighted making use of simple model systems/approximations. Furthermore, we predict V(o) 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.

  5. 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.

  6. 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. The variation of voltages in matter can be measured by experiment, however, modern supercomputers allow the calculation of accurate quantum voltages with spatial resolutions of bulk systems well beyond what can currently be measured provided a sufficient level of theory is employed. Of particular interest is the Mean Inner Potential (V{sub o}) – the spatial average of these quantum voltages referenced to the vacuum. Here we establish a protocol to reliably evaluate V{sub o} from quantum calculations. 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 V{sub o} for vitrified water and salt crystals and demonstrate the impact of covalent and ionic bonding as well as intermolecular/atomic interactions. Certain aspects in this regard are highlighted making use of simple model systems/approximations. Furthermore, we predict V{sub o} 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.

  7. Manipulating photoinduced voltage in metasurface with circularly polarized light.

    PubMed

    Bai, Qiang

    2015-02-23

    Recently, the concept of metasurface has provided one an unprecedented opportunity and ability to control the light in the deep subwavelength scale. However, so far most efforts are devoted to exploiting the novel scattering properties and applications of metasurface in optics. Here, I theoretically and numerically demonstrate that longitudinal and transverse photoinduced voltages can be simultaneously realized in the proposed metasurface utilizing the magnetic resonance under the normal incidence of circularly polarized light, which may extend the concept and functionality of metasurface into the electronics and may provide a potential scheme to realize a nanoscale tunable voltage source through a nanophotonic roadmap. The signs of longitudinal and transverse photoin-duced voltages can be manipulated by tuning the resonant frequency and the handedness of circularly polarized light, respectively. Analytical formulae of photoinduced voltage are presented based on the theory of symmetry of field. This work may bridge nanophotonics and electronics, expands the capability of metasurface and has many potential applications. PMID:25836566

  8. Design & Fabrication of a High-Voltage Photovoltaic Cell

    SciTech Connect

    Felder, Jennifer; /North Carolina State U. /SLAC

    2012-09-05

    Silicon photovoltaic (PV) cells are alternative energy sources that are important in sustainable power generation. Currently, applications of PV cells are limited by the low output voltage and somewhat low efficiency of such devices. In light of this fact, this project investigates the possibility of fabricating high-voltage PV cells on float-zone silicon wafers having output voltages ranging from 50 V to 2000 V. Three designs with different geometries of diffusion layers were simulated and compared in terms of metal coverage, recombination, built-in potential, and conduction current density. One design was then chosen and optimized to be implemented in the final device design. The results of the simulation serve as a feasibility test for the design concept and provide supportive evidence of the effectiveness of silicon PV cells as high-voltage power supplies.

  9. Spectroscopic and Structural Investigations of alpha-beta-, and gamma-AIH3 Phases

    SciTech Connect

    Manciu, F.S.; Graetz, J.; Reza, L.; Durrer, W.G.; Bronson, A.; Lacina, D.

    2010-07-01

    With its reputation as a high-energy density fuel, aluminum hydride (AlH{sub 3}) has received renewed attention as a material that is particularly suitable, not only for hydrogen storage but also for rocket propulsion. While the various phases of AlH{sub 3} have been investigated theoretically, there is a shortage of experimental studies corroborating the theoretical findings. In response to this, we present here an investigation of these compounds based primarily on two research areas in which there is the greatest scarcity of information in the literature, namely Raman and infrared (IR) absorption analysis. To the authors knowledge, this is the first report of experimental far-IR absorption results on these compounds. Two different samples prepared by broadly similar ethereal reactions of AlCl{sub 3} with LiAlH{sub 4} were analyzed. Both Raman and IR absorption measurements indicate that one sample is purely {gamma}-AlH{sub 3} and that the other is a mixture of {alpha}-, {beta}-, and {gamma}-AlH{sub 3} phases. X-ray diffraction confirms the spectroscopic findings, most notably for the {beta}-AlH{sub 3} phase, for which optical spectroscopic data are reported here for the first time.

  10. On voltage collapse in electric power systems

    SciTech Connect

    Chiang, H.D.; Dobson, I.; Thomas, R.J.; Thorp, J.S.; Fekih-Ahmed, L. . School of Electrical Engineering)

    1990-05-01

    Several voltage collapses have had a period of slowly decreasing voltage followed by an accelerating collapse in voltage. This paper analyzes this type of voltage collapse based on a center manifold voltage collapse model. The essence of this model is that the system dynamics after bifurcation are captured by the center manifold trajectory and it is a computable model that allows prediction of voltage collapse. Both physical explanations and computational considerations of this model are presented. The authors clarify the use of static and dynamic models to explain voltage collapse. Voltage collapse dynamics are demonstrated on a simple power system model.

  11. Control of Analyte Electrolysis in Electrospray Ionization Mass Spectrometry Using Repetitively Pulsed High Voltage

    SciTech Connect

    Kertesz, Vilmos; Van Berkel, Gary J

    2011-01-01

    Analyte electrolysis using a repetitively pulsed high voltage ion source was investigated and compared to that using a regular, continuously operating direct current high voltage ion source in electrospray ionization mass spectrometry. The extent of analyte electrolysis was explored as a function of the length and frequency of the high voltage pulse using the model compound reserpine in positive ion mode. Using +5 kV as the maximum high voltage amplitude, reserpine was oxidized to its 2, 4, 6 and 8-electron oxidation products when direct current high voltage was employed. In contrast, when using a pulsed high voltage, oxidation of reserpine was eliminated by employing the appropriate high voltage pulse length and frequency. This effect was caused by inefficient mass transport of the analyte to the electrode surface during the duration of the high voltage pulse and the subsequent relaxation of the emitter electrode/ electrolyte interface during the time period when the high voltage was turned off. This mode of ESI source operation allows for analyte electrolysis to be quickly and simply switched on or off electronically via a change in voltage pulse variables.

  12. Electrode voltage fall and total voltage of a transient arc

    NASA Astrophysics Data System (ADS)

    Valensi, F.; Ratovoson, L.; Razafinimanana, M.; Masquère, M.; Freton, P.; Gleizes, A.

    2016-06-01

    This paper deals with an experimental study of the components of a transient arc total voltage with duration of a few tens of ms and a current peak close to 1000 A. The cathode tip is made of graphite whereas the flat anode is made either of copper or of graphite; the electrodes gap is a few mm. The analysis of the electrical parameters is supported and validated by fast imaging and by two models: the first one is a 2D physical model of the arc allowing to calculate both the plasma temperature field and the arc voltage; the second model is able to estimate the transient heating of the graphite electrode. The main aim of the study was to detect the possible change of the cathode voltage fall (CVF) during the first instants of the arc. Indeed it is expected that during the first ms the graphite cathode is rather cool and the main mechanism of the electron emission should be the field effect emission, whereas after several tens of ms the cathode is strongly heated and thermionic emission should be predominant. We have observed some change in the apparent CVF but we have shown that this apparent change can be attributed to the variation of the solid cathode resistance. On the other hand, the possible change of CVF corresponding to the transition between a ‘cold’ and a ‘hot’ cathode should be weak and could not be characterized considering our measurement uncertainty of about 2 V. The arc column voltage (ACV) was estimated by subtracting the electrode voltage fall from the total arc voltage. The experimental transient evolution of the ACV is in very good agreement with the theoretical variation predicted by the model, showing the good ability of the model to study this kind of transient arc.

  13. Electro-optic voltage sensor for sensing voltage in an E-field

    DOEpatents

    Davidson, James R.; Crawford, Thomas M.; Seifert, Gary D.

    2002-03-26

    A miniature electro-optic voltage sensor and system capable of accurate operation at high voltages has a sensor body disposed in an E-field. The body receives a source beam of electromagnetic radiation. A polarization beam displacer separates the source light beam into two beams with orthogonal linear polarizations. A wave plate rotates the linear polarization to rotated polarization. A transducer utilizes Pockels electro-optic effect and induces a differential phase shift on the major and minor axes of the rotated polarization in response to the E-field. A prism redirects the beam back through the transducer, wave plate, and polarization beam displacer. The prism also converts the rotated polarization to circular or elliptical polarization. The wave plate rotates the major and minor axes of the circular or elliptical polarization to linear polarization. The polarization beam displacer separates the beam into two beams of orthogonal linear polarization representing the major and minor axes. The system may have a transmitter for producing the beam of electro-magnetic radiation; a detector for converting the two beams into electrical signals; and a signal processor for determining the voltage.

  14. Apparatus Characterizes Transient Voltages in Real Time

    NASA Technical Reports Server (NTRS)

    Medelius, Pedro

    2005-01-01

    The figure shows a prototype of a relatively inexpensive electronic monitoring apparatus that measures and records selected parameters of lightning-induced transient voltages on communication and power cables. The selected parameters, listed below, are those most relevant to the ability of lightning-induced transients to damage electronic equipment. This apparatus bridges a gap between some traditional transient-voltage recorders that record complete waveforms and other traditional transient-voltage recorders that record only peak values: By recording the most relevant parameters and only those parameters this apparatus yields more useful information than does a traditional peak-value (only) recorder while imposing much smaller data-storage and data-transmission burdens than does a traditional complete-waveform recorder. Also, relative to a complete-waveform recorder, this apparatus is more reliable and can be built at lower cost because it contains fewer electronic components. The transients generated by sources other than lightning tend to have frequency components well below 1 MHz. Most commercial transient recorders can detect and record such transients, but cannot respond rapidly enough for recording lightning-induced transient voltage peaks, which can rise from 10 to 90 percent of maximum amplitude in a fraction of a microsecond. Moreover, commercial transient recorders cannot rearm themselves rapidly enough to respond to the multiple transients that occur within milliseconds of each other on some lightning strikes. One transient recorder, designed for Kennedy Space Center earlier [ Fast Transient-Voltage Recorder (KSC- 11991), NASA Tech Briefs, Vol. 23, No. 10, page 6a (October 1999)], is capable of sampling transient voltages at peak values up to 50 V in four channels at a rate of 20 MHz. That recorder contains a trigger circuit that continuously compares the amplitudes of the signals on four channels to a preset triggering threshold. When a trigger signal

  15. Stabilization of ZnMnO3 Phase from Sol-gel Synthesized Nitrate Precursors

    SciTech Connect

    Saraf, Laxmikant V.; Nachimuthu, Ponnusamy; Engelhard, Mark H.; Baer, Donald R.

    2010-02-01

    The stabilization and analysis of pure ZnMnO3 spinel phase may help to understand the solubility limits of Mn in ZnO in wurtzite and spinel cubic structures. In this report, synthesis and characterization of stable ZnMnO3 phase is discussed which is extracted from sol-gel synthesis of zinc and manganese nitrate precursors. The reflections at higher diffraction angles for this known cubic system with space group Fd3m were calculated with the help of JADE 8.0 program. High resolution X-ray photoelectron spectroscopy measurements of Mn3p position of ZnMnO3 compared with ZnMn2O4 showed a higher binding energy shift ~0.85 eV indicating Mn4+ valence state in ZnMnO3.

  16. Cost-Optimal Design of a 3-Phase Core Type Transformer by Gradient Search Technique

    NASA Astrophysics Data System (ADS)

    Basak, R.; Das, A.; Sensarma, A. K.; Sanyal, A. N.

    2014-04-01

    3-phase core type transformers are extensively used as power and distribution transformers in power system and their cost is a sizable proportion of the total system cost. Therefore they should be designed cost-optimally. The design methodology for reaching cost-optimality has been discussed in details by authors like Ramamoorty. It has also been discussed in brief in some of the text-books of electrical design. The paper gives a method for optimizing design, in presence of constraints specified by the customer and the regulatory authorities, through gradient search technique. The starting point has been chosen within the allowable parameter space the steepest decent path has been followed for convergence. The step length has been judiciously chosen and the program has been maneuvered to avoid local minimal points. The method appears to be best as its convergence is quickest amongst different optimizing techniques.

  17. Modulated voltage metastable ionization detector

    NASA Technical Reports Server (NTRS)

    Carle, G. C.; Kojiro, D. R.; Humphrey, D. E. (Inventor)

    1985-01-01

    The output current from a metastable ionization detector (MID) is applied to a modulation voltage circuit. An adjustment is made to balance out the background current, and an output current, above background, is applied to an input of a strip chart recorder. For low level concentrations, i.e., low detected output current, the ionization potential will be at a maximum and the metastable ionization detector will operate at its most sensitive level. When the detected current from the metastable ionization detector increases above a predetermined threshold level, a voltage control circuit is activated which turns on a high voltage transistor which acts to reduce the ionization potential. The ionization potential applied to the metastable ionization detector is then varied so as to maintain the detected signal level constant. The variation in ionization potential is now related to the concentration of the constituent and a representative amplitude is applied to another input of said strip chart recorder.

  18. Voltage-Gated Hydrophobic Nanopores

    SciTech Connect

    Lavrik, Nickolay V

    2011-01-01

    Hydrophobicity is a fundamental property that is responsible for numerous physical and biophysical aspects of molecular interactions in water. Peculiar behavior is expected for water in the vicinity of hydrophobic structures, such as nanopores. Indeed, hydrophobic nanopores can be found in two distinct states, dry and wet, even though the latter is thermodynamically unstable. Transitions between these two states are kinetically hindered in long pores but can be much faster in shorter pores. As it is demonstrated for the first time in this paper, these transitions can be induced by applying a voltage across a membrane with a single hydrophobic nanopore. Such voltage-induced gating in single nanopores can be realized in a reversible manner through electrowetting of inner walls of the nanopores. The resulting I-V curves of such artificial hydrophobic nanopores mimic biological voltage-gated channels.

  19. Ancillary service details: Voltage control

    SciTech Connect

    Kirby, B.; Hirst, E.

    1997-12-01

    Voltage control is accomplished by managing reactive power on an alternating-current power system. Reactive power can be produced and absorbed by both generation and transmission equipment. Reactive-power devices differ substantially in the magnitude and speed of response and in their capital costs. System operators, transmission owners, generators, customers, power marketers, and government regulators need to pay close attention to voltage control as they restructure the U.S. electricity industry. Voltage control can affect reliability and commerce in three ways: (1) Voltages must be maintained within an acceptable range for both customer and power-system equipment to function properly. (2) The movement of reactive power consumes transmission resources, which limits the ability to move real power and worsens congestion. (3) The movement of reactive power results in real-power losses. When generators are required to supply excessive amounts of reactive power, their real-power production must be curtailed. These opportunity costs are not currently compensated for in most regions. Current tariffs are based on embedded costs. These embedded-cost tariffs average about $0.51/MWh, equivalent to $1.5 billion annually for the United States as a whole. Although this cost is low when compared with the cost of energy, it still aggregates to a significant amount of money. This report takes a basic look at why the power system requires reactive power (an appendix explains the fundamentals of real and reactive power). The report then examines the various types of generation and transmission resources used to supply reactive power and to control voltage. Finally it discusses how these resources are deployed and paid for in several reliability regions around the country. As the U.S. electricity industry is restructured, the generation, transmission, and system-control equipment and functions that maintain voltages within the appropriate ranges are being deintegrated.

  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. Low Voltage Spatial Light Modulator

    SciTech Connect

    Papavasiliou, A

    2003-02-19

    This project studied the feasibility of a Low-Voltage actuator technology that promises to reduce the switched voltage requirements and linearize the response of spatial light modulators. We created computer models that demonstrate substantial advantages offered by this technology, and fabricated and tested those devices. SLMs are electro-optic devices for modulating the phase, amplitude or angle of light beams, laser or other. Applications for arrays of SLMs include turbulence correction for high-speed optical communications, imaging through distorting media, input devices for holographic memories, optical manipulation of DNA molecules, and optical computers. Devices based on micro electro-mechanical systems (MEMS) technology have recently become of special interest because of their potential for greatly improved performance at a much lower cost than piezoelectric or liquid crystal based devices. The new MEMS-based SLM devices could have important applications in high-speed optical communication and remote optical sensing, in support of DoD and DOE missions. Virtually all previously demonstrated MEMS SLMs are based on parallel-plate capacitors where an applied voltage causes a mirror attached to a suspended electrode to move towards a fixed electrode. They require relatively high voltages, typically on the order of 100 V, resulting in (1) large transistor sizes, available only from specialized foundries at significant cost and limiting the amount/sophistication of electronics under each SLM pixel, and (2) large power dissipation/area, resulting in a heat removal issue because of the optical precision required ({approx} 1/50-th of a wavelength). The actuator described in this process uses an advanced geometry that was invented at LLNL and is currently still proprietary. The new geometry allows the application of a bias voltage. This applied bias voltage results in a reduction of the required switched voltage and a linearization of the response curve. When this

  2. High Input Voltage, Silicon Carbide Power Processing Unit Performance Demonstration

    NASA Technical Reports Server (NTRS)

    Bozak, Karin E.; Pinero, Luis R.; Scheidegger, Robert J.; Aulisio, Michael V.; Gonzalez, Marcelo C.; Birchenough, Arthur G.

    2015-01-01

    A silicon carbide brassboard power processing unit has been developed by the NASA Glenn Research Center in Cleveland, Ohio. The power processing unit operates from two sources: a nominal 300 Volt high voltage input bus and a nominal 28 Volt low voltage input bus. The design of the power processing unit includes four low voltage, low power auxiliary supplies, and two parallel 7.5 kilowatt (kW) discharge power supplies that are capable of providing up to 15 kilowatts of total power at 300 to 500 Volts (V) to the thruster. Additionally, the unit contains a housekeeping supply, high voltage input filter, low voltage input filter, and master control board, such that the complete brassboard unit is capable of operating a 12.5 kilowatt Hall effect thruster. The performance of the unit was characterized under both ambient and thermal vacuum test conditions, and the results demonstrate exceptional performance with full power efficiencies exceeding 97%. The unit was also tested with a 12.5kW Hall effect thruster to verify compatibility and output filter specifications. With space-qualified silicon carbide or similar high voltage, high efficiency power devices, this would provide a design solution to address the need for high power electric propulsion systems.

  3. High Input Voltage, Silicon Carbide Power Processing Unit Performance Demonstration

    NASA Technical Reports Server (NTRS)

    Bozak, Karin E.; Pinero, Luis R.; Scheidegger, Robert J.; Aulisio, Michael V.; Gonzalez, Marcelo C.; Birchenough, Arthur G.

    2015-01-01

    A silicon carbide brassboard power processing unit has been developed by the NASA Glenn Research Center in Cleveland, Ohio. The power processing unit operates from two sources - a nominal 300-Volt high voltage input bus and a nominal 28-Volt low voltage input bus. The design of the power processing unit includes four low voltage, low power supplies that provide power to the thruster auxiliary supplies, and two parallel 7.5 kilowatt power supplies that are capable of providing up to 15 kilowatts of total power at 300-Volts to 500-Volts to the thruster discharge supply. Additionally, the unit contains a housekeeping supply, high voltage input filter, low voltage input filter, and master control board, such that the complete brassboard unit is capable of operating a 12.5 kilowatt Hall Effect Thruster. The performance of unit was characterized under both ambient and thermal vacuum test conditions, and the results demonstrate the exceptional performance with full power efficiencies exceeding 97. With a space-qualified silicon carbide or similar high voltage, high efficiency power device, this design could evolve into a flight design for future missions that require high power electric propulsion systems.

  4. Developing Fast Fluorescent Protein Voltage Sensors by Optimizing FRET Interactions

    PubMed Central

    Sung, Uhna; Sepehri-Rad, Masoud; Piao, Hong Hua; Jin, Lei; Hughes, Thomas; Cohen, Lawrence B.; Baker, Bradley J.

    2015-01-01

    FRET (Förster Resonance Energy Transfer)-based protein voltage sensors can be useful for monitoring neuronal activity in vivo because the ratio of signals between the donor and acceptor pair reduces common sources of noise such as heart beat artifacts. We improved the performance of FRET based genetically encoded Fluorescent Protein (FP) voltage sensors by optimizing the location of donor and acceptor FPs flanking the voltage sensitive domain of the Ciona intestinalis voltage sensitive phosphatase. First, we created 39 different “Nabi1” constructs by positioning the donor FP, UKG, at 8 different locations downstream of the voltage-sensing domain and the acceptor FP, mKO, at 6 positions upstream. Several of these combinations resulted in large voltage dependent signals and relatively fast kinetics. Nabi1 probes responded with signal size up to 11% ΔF/F for a 100 mV depolarization and fast response time constants both for signal activation (~2 ms) and signal decay (~3 ms). We improved expression in neuronal cells by replacing the mKO and UKG FRET pair with Clover (donor FP) and mRuby2 (acceptor FP) to create Nabi2 probes. Nabi2 probes also had large signals and relatively fast time constants in HEK293 cells. In primary neuronal culture, a Nabi2 probe was able to differentiate individual action potentials at 45 Hz. PMID:26587834

  5. Developing Fast Fluorescent Protein Voltage Sensors by Optimizing FRET Interactions.

    PubMed

    Sung, Uhna; Sepehri-Rad, Masoud; Piao, Hong Hua; Jin, Lei; Hughes, Thomas; Cohen, Lawrence B; Baker, Bradley J

    2015-01-01

    FRET (Förster Resonance Energy Transfer)-based protein voltage sensors can be useful for monitoring neuronal activity in vivo because the ratio of signals between the donor and acceptor pair reduces common sources of noise such as heart beat artifacts. We improved the performance of FRET based genetically encoded Fluorescent Protein (FP) voltage sensors by optimizing the location of donor and acceptor FPs flanking the voltage sensitive domain of the Ciona intestinalis voltage sensitive phosphatase. First, we created 39 different "Nabi1" constructs by positioning the donor FP, UKG, at 8 different locations downstream of the voltage-sensing domain and the acceptor FP, mKO, at 6 positions upstream. Several of these combinations resulted in large voltage dependent signals and relatively fast kinetics. Nabi1 probes responded with signal size up to 11% ΔF/F for a 100 mV depolarization and fast response time constants both for signal activation (~2 ms) and signal decay (~3 ms). We improved expression in neuronal cells by replacing the mKO and UKG FRET pair with Clover (donor FP) and mRuby2 (acceptor FP) to create Nabi2 probes. Nabi2 probes also had large signals and relatively fast time constants in HEK293 cells. In primary neuronal culture, a Nabi2 probe was able to differentiate individual action potentials at 45 Hz. PMID:26587834

  6. Incrementally Variable High-Voltage Supply

    NASA Technical Reports Server (NTRS)

    Potter, D. W.; Chin, J.; Anderson, H. R.; Loveless, R. L.

    1985-01-01

    Programable power supply provides regulated output ranging from 2.5 to 2,500 volts. Exponential digital-to-analog converter provides low-voltage analog signal to power converter and to negative and positive high-voltage regulators. In response, converter furnishes voltage of approximate magnitude represented by analog signal, and regulators adjust voltage to precise magnitude. Entire voltage range covered in 169 steps. Total power consumption expected to be less than 2 watts.

  7. Effects of Electrode Material on the Voltage of a Tree-Based Energy Generator

    PubMed Central

    2015-01-01

    The voltage between a standing tree and its surrounding soil is regarded as an innovative renewable energy source. This source is expected to provide a new power generation system for the low-power electrical equipment used in forestry. However, the voltage is weak, which has caused great difficulty in application. Consequently, the development of a method to increase the voltage is a key issue that must be addressed in this area of applied research. As the front-end component for energy harvesting, a metal electrode has a material effect on the level and stability of the voltage obtained. This study aimed to preliminarily ascertain the rules and mechanisms that underlie the effects of electrode material on voltage. Electrodes of different materials were used to measure the tree-source voltage, and the data were employed in a comparative analysis. The results indicate that the conductivity of the metal electrode significantly affects the contact resistance of the electrode-soil and electrode-trunk contact surfaces, thereby influencing the voltage level. The metal reactivity of the electrode has no significant effect on the voltage. However, passivation of the electrode materials markedly reduces the voltage. Suitable electrode materials are demonstrated and recommended. PMID:26302491

  8. Novel bandgap-based under-voltage-lockout methods with high reliability

    NASA Astrophysics Data System (ADS)

    Yongrui, Zhao; Xinquan, Lai

    2013-10-01

    Highly reliable bandgap-based under-voltage-lockout (UVLO) methods are presented in this paper. The proposed under-voltage state to signal conversion methods take full advantages of the high temperature stability characteristics and the enhancement low-voltage protection methods which protect the core circuit from error operation; moreover, a common-source stage amplifier method is introduced to expand the output voltage range. All of these methods are verified in a UVLO circuit fabricated with a 0.5 μm standard BCD process technology. The experimental result shows that the proposed bandgap method exhibits a good temperature coefficient of 20 ppm/°C, which ensures that the UVLO keeps a stable output until the under-voltage state changes. Moreover, at room temperature, the high threshold voltage VTH+ generated by the UVLO is 12.3 V with maximum drift voltage of ±80 mV, and the low threshold voltage VTH- is 9.5 V with maximum drift voltage of ±70 mV. Also, the low voltage protection method used in the circuit brings a high reliability when the supply voltage is very low.

  9. Voltage control of ferromagnetic resonance

    NASA Astrophysics Data System (ADS)

    Zhou, Ziyao; Peng, Bin; Zhu, Mingmin; Liu, Ming

    2016-05-01

    Voltage control of magnetism in multiferroics, where the ferromagnetism and ferroelectricity are simultaneously exhibiting, is of great importance to achieve compact, fast and energy efficient voltage controllable magnetic/microwave devices. Particularly, these devices are widely used in radar, aircraft, cell phones and satellites, where volume, response time and energy consumption is critical. Researchers realized electric field tuning of magnetic properties like magnetization, magnetic anisotropy and permeability in varied multiferroic heterostructures such as bulk, thin films and nanostructure by different magnetoelectric (ME) coupling mechanism: strain/stress, interfacial charge, spin-electromagnetic (EM) coupling and exchange coupling, etc. In this review, we focus on voltage control of ferromagnetic resonance (FMR) in multiferroics. ME coupling-induced FMR change is critical in microwave devices, where the electric field tuning of magnetic effective anisotropic field determines the tunability of the performance of microwave devices. Experimentally, FMR measurement technique is also an important method to determine the small effective magnetic field change in small amount of magnetic material precisely due to its high sensitivity and to reveal the deep science of multiferroics, especially, voltage control of magnetism in novel mechanisms like interfacial charge, spin-EM coupling and exchange coupling.

  10. High Voltage Space Solar Arrays

    NASA Technical Reports Server (NTRS)

    Ferguson, D. C.; Hillard, G. B.; Vayner, B. V.; Galofaro, J. T.; Lyons, Valerie (Technical Monitor)

    2002-01-01

    Recent tests performed at the NASA Glenn Research Center and elsewhere have shown promise in the design and construction of high voltage (300-1000 V) solar arrays for space applications. Preliminary results and implications for solar array design will be discussed, with application to direct-drive electric propulsion and space solar power.

  11. LHCb calorimeters high voltage system

    NASA Astrophysics Data System (ADS)

    Gilitsky, Yu.; Golutvin, A.; Konoplyannikov, A.; Lefrancois, J.; Perret, P.; Schopper, A.; Soldatov, M.; Yakimchuk, V.

    2007-02-01

    The calorimeter system in LHCb aims to identify electrons, photons and hadrons. All calorimeters are equipped with Hamamatsu photo tubes as devices for light to signal conversion. Eight thousand R7899-20 tubes are used for electromagnetic and hadronic calorimeters and two hundred 64 channels multi-anode R7600-00-M64 for Scintillator-Pad/Preshower detectors. The calorimeter high voltage (HV) system is based on a Cockroft Walton (CW) voltage converter and a control board connected to the Experiment Control System (ECS) by serial bus. The base of each photomultiplier tube (PMT) is built with a high voltage converter and constructed on an individual printed circuit board, using compact surface mount components. The base is attached directly to the PMT. There are no HV cables in the system. A Field Programmable Gate Array (FPGA) is used on the control board as an interface between the ECS and the 200 control channels. The FPGA includes also additional functionalities allowing automated monitoring and ramp up of the high voltage values. This paper describes the HV system architecture, some technical details of the electronics implementation and summarizes the system performance. This safe and low power consumption HV electronic system for the photomultiplier tubes can be used for various biomedical apparatus too.

  12. High-Voltage Droplet Dispenser

    NASA Technical Reports Server (NTRS)

    Eichenberg, Dennis J.

    2003-01-01

    An apparatus that is extremely effective in dispensing a wide range of droplets has been developed. This droplet dispenser is unique in that it utilizes a droplet bias voltage, as well as an ionization pulse, to release a droplet. Apparatuses that deploy individual droplets have been used in many applications, including, notably, study of combustion of liquid fuels. Experiments on isolated droplets are useful in that they enable the study of droplet phenomena under well-controlled and simplified conditions. In this apparatus, a syringe dispenses a known value of liquid, which emerges from, and hangs onto, the outer end of a flat-tipped, stainless steel needle. Somewhat below the needle tip and droplet is a ring electrode. A bias high voltage, followed by a high-voltage pulse, is applied so as to attract the droplet sufficiently to pull it off the needle. The voltages are such that the droplet and needle are negatively charged and the ring electrode is positively charged.

  13. Miniature x-ray source

    DOEpatents

    Trebes, James E.; Bell, Perry M.; Robinson, Ronald B.

    2000-01-01

    A miniature x-ray source utilizing a hot filament cathode. The source has a millimeter scale size and is capable of producing broad spectrum x-ray emission over a wide range of x-ray energies. The miniature source consists of a compact vacuum tube assembly containing the hot filament cathode, an anode, a high voltage feedthru for delivering high voltage to the cathode, a getter for maintaining high vacuum, a connector for initial vacuum pump down and crimp-off, and a high voltage connection for attaching a compact high voltage cable to the high voltage feedthru. At least a portion of the vacuum tube wall is fabricated from highly x-ray transparent materials, such as sapphire, diamond, or boron nitride.

  14. Miniature x-ray source

    DOEpatents

    Trebes, James E.; Stone, Gary F.; Bell, Perry M.; Robinson, Ronald B.; Chornenky, Victor I.

    2002-01-01

    A miniature x-ray source capable of producing broad spectrum x-ray emission over a wide range of x-ray energies. The miniature x-ray source comprises a compact vacuum tube assembly containing a cathode, an anode, a high voltage feedthru for delivering high voltage to the anode, a getter for maintaining high vacuum, a connection for an initial vacuum pump down and crimp-off, and a high voltage connection for attaching a compact high voltage cable to the high voltage feedthru. At least a portion of the vacuum tube wall is highly x-ray transparent and made, for example, from boron nitride. The compact size and potential for remote operation allows the x-ray source, for example, to be placed adjacent to a material sample undergoing analysis or in proximity to the region to be treated for medical applications.

  15. Voltage-gated Proton Channels

    PubMed Central

    DeCoursey, Thomas E.

    2014-01-01

    Voltage-gated proton channels, HV1, have vaulted from the realm of the esoteric into the forefront of a central question facing ion channel biophysicists, namely the mechanism by which voltage-dependent gating occurs. This transformation is the result of several factors. Identification of the gene in 2006 revealed that proton channels are homologues of the voltage-sensing domain of most other voltage-gated ion channels. Unique, or at least eccentric, properties of proton channels include dimeric architecture with dual conduction pathways, perfect proton selectivity, a single-channel conductance ~103 smaller than most ion channels, voltage-dependent gating that is strongly modulated by the pH gradient, ΔpH, and potent inhibition by Zn2+ (in many species) but an absence of other potent inhibitors. The recent identification of HV1 in three unicellular marine plankton species has dramatically expanded the phylogenetic family tree. Interest in proton channels in their own right has increased as important physiological roles have been identified in many cells. Proton channels trigger the bioluminescent flash of dinoflagellates, facilitate calcification by coccolithophores, regulate pH-dependent processes in eggs and sperm during fertilization, secrete acid to control the pH of airway fluids, facilitate histamine secretion by basophils, and play a signaling role in facilitating B-cell receptor mediated responses in B lymphocytes. The most elaborate and best-established functions occur in phagocytes, where proton channels optimize the activity of NADPH oxidase, an important producer of reactive oxygen species. Proton efflux mediated by HV1 balances the charge translocated across the membrane by electrons through NADPH oxidase, minimizes changes in cytoplasmic and phagosomal pH, limits osmotic swelling of the phagosome, and provides substrate H+ for the production of H2O2 and HOCl, reactive oxygen species crucial to killing pathogens. PMID:23798303

  16. Voltage-gated proton channels.

    PubMed

    Decoursey, Thomas E

    2012-04-01

    Voltage-gated proton channels, HV1, have vaulted from the realm of the esoteric into the forefront of a central question facing ion channel biophysicists, namely, the mechanism by which voltage-dependent gating occurs. This transformation is the result of several factors. Identification of the gene in 2006 revealed that proton channels are homologues of the voltage-sensing domain of most other voltage-gated ion channels. Unique, or at least eccentric, properties of proton channels include dimeric architecture with dual conduction pathways, perfect proton selectivity, a single-channel conductance approximately 10(3) times smaller than most ion channels, voltage-dependent gating that is strongly modulated by the pH gradient, ΔpH, and potent inhibition by Zn(2+) (in many species) but an absence of other potent inhibitors. The recent identification of HV1 in three unicellular marine plankton species has dramatically expanded the phylogenetic family tree. Interest in proton channels in their own right has increased as important physiological roles have been identified in many cells. Proton channels trigger the bioluminescent flash of dinoflagellates, facilitate calcification by coccolithophores, regulate pH-dependent processes in eggs and sperm during fertilization, secrete acid to control the pH of airway fluids, facilitate histamine secretion by basophils, and play a signaling role in facilitating B-cell receptor mediated responses in B-lymphocytes. The most elaborate and best-established functions occur in phagocytes, where proton channels optimize the activity of NADPH oxidase, an important producer of reactive oxygen species. Proton efflux mediated by HV1 balances the charge translocated across the membrane by electrons through NADPH oxidase, minimizes changes in cytoplasmic and phagosomal pH, limits osmotic swelling of the phagosome, and provides substrate H(+) for the production of H2O2 and HOCl, reactive oxygen species crucial to killing pathogens.

  17. Module Five: Relationships of Current, Voltage, and Resistance; Basic Electricity and Electronics Individualized Learning System.

    ERIC Educational Resources Information Center

    Bureau of Naval Personnel, Washington, DC.

    This module covers the relationships between current and voltage; resistance in a series circuit; how to determine the values of current, voltage, resistance, and power in resistive series circuits; the effects of source internal resistance; and an introduction to the troubleshooting of series circuits. This module is divided into five lessons:…

  18. 30 CFR 77.802 - Protection of high-voltage circuits; neutral grounding resistors; disconnecting devices.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... grounding resistors; disconnecting devices. 77.802 Section 77.802 Mineral Resources MINE SAFETY AND HEALTH... of high-voltage circuits; neutral grounding resistors; disconnecting devices. High-voltage circuits... grounded through a suitable resistor at the source transformers, and a grounding circuit, originating...

  19. 30 CFR 77.802 - Protection of high-voltage circuits; neutral grounding resistors; disconnecting devices.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... grounding resistors; disconnecting devices. 77.802 Section 77.802 Mineral Resources MINE SAFETY AND HEALTH... of high-voltage circuits; neutral grounding resistors; disconnecting devices. High-voltage circuits... grounded through a suitable resistor at the source transformers, and a grounding circuit, originating...

  20. 30 CFR 77.802 - Protection of high-voltage circuits; neutral grounding resistors; disconnecting devices.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... grounding resistors; disconnecting devices. 77.802 Section 77.802 Mineral Resources MINE SAFETY AND HEALTH... of high-voltage circuits; neutral grounding resistors; disconnecting devices. High-voltage circuits... grounded through a suitable resistor at the source transformers, and a grounding circuit, originating...

  1. 30 CFR 77.802 - Protection of high-voltage circuits; neutral grounding resistors; disconnecting devices.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... grounding resistors; disconnecting devices. 77.802 Section 77.802 Mineral Resources MINE SAFETY AND HEALTH... of high-voltage circuits; neutral grounding resistors; disconnecting devices. High-voltage circuits... grounded through a suitable resistor at the source transformers, and a grounding circuit, originating...

  2. Eleven years of monitoring an ultra-stable 10 V zener-based voltage standard

    NASA Astrophysics Data System (ADS)

    de Souza, H.; Trigo, L.; Slomovitz, D.

    2016-07-01

    The long-term behaviour of a voltage standard based on 140 zeners is analyzed. This standard was developed in 2004 and was monitored up to now. Noise and drift are evaluated showing better results than commercial similar devices. This source is used as the National Voltage Standard in the Uruguayan Designated National Metrology Institute (UTE).

  3. High voltage battery cell scanner development

    NASA Technical Reports Server (NTRS)

    Lepisto, J. W.; Decker, D. K.; Graves, J.

    1983-01-01

    Battery cell voltage scanners have been previously used in low voltage spacecraft applications. In connection with future missions involving an employment of high-power high voltage power subsystems and/or autonomous power subsystem management for unattended operation, it will be necessary to utilize battery cell voltage scanners to provide battery cell voltage information for early detection of impending battery cell degradation/failures. In preparation for such missions, a novel battery cell voltage scanner design has been developed. The novel design makes use of low voltage circuit modules which can be applied to high voltage batteries in a building block fashion. A description is presented of the design concept and test results of the high voltage battery cell scanner, and its operation with an autonomously managed power subsystem is discussed.

  4. High voltage switch triggered by a laser-photocathode subsystem

    DOEpatents

    Chen, Ping; Lundquist, Martin L.; Yu, David U. L.

    2013-01-08

    A spark gap switch for controlling the output of a high voltage pulse from a high voltage source, for example, a capacitor bank or a pulse forming network, to an external load such as a high gradient electron gun, laser, pulsed power accelerator or wide band radar. The combination of a UV laser and a high vacuum quartz cell, in which a photocathode and an anode are installed, is utilized as triggering devices to switch the spark gap from a non-conducting state to a conducting state with low delay and low jitter.

  5. Spontaneous formation of superconducting NiBi{sub 3} phase in Ni-Bi bilayer films

    SciTech Connect

    Siva, Vantari; Senapati, Kartik Prusty, Sudakshina; Sahoo, Pratap K.; Satpati, Biswarup

    2015-02-28

    We report the spontaneous formation of superconducting NiBi{sub 3} phase in thermally evaporated Ni-Bi bilayer films. High reaction-diffusion coefficient of Bi is believed to drive the formation of NiBi{sub 3} during the deposition of Bi on the Ni film. Cross sectional transmission electron microscopy and glancing incidence X-ray depth profiling confirmed the presence of NiBi{sub 3} throughout the top Bi layer. Superconducting transition at ∼3.9 K, close to the bulk value, was confirmed by transport and magnetization measurements. The bilayers were irradiated with varying fluence of 100 MeV Au ions to study the robustness of superconducting order in presence of large concentration of defects. Superconducting parameters of NiBi{sub 3}, such as transition temperature and upper critical field, remained unchanged upto an ion dose of 1 × 10{sup 14} ions/cm{sup 2}. The diffusive formation of NiBi{sub 3} in Ni opens the possibility of studying superconducting proximity effect at a truly clean superconductor-ferromagnet interface.

  6. First-principles study of amorphous Ga4Sb6Te3 phase-change alloys

    NASA Astrophysics Data System (ADS)

    Bouzid, Assil; Gabardi, Silvia; Massobrio, Carlo; Boero, Mauro; Bernasconi, Marco

    2015-05-01

    First-principles molecular dynamics simulations within the density functional theory framework were performed to generate amorphous models of the Ga4Sb6Te3 phase change alloy by quenching from the melt. We find that Ga-Sb and Ga-Te are the most abundant bonds with only a minor amount of Sb-Te bonds participating to the alloy network. Ga and four-coordinated Sb atoms present a tetrahedral-like geometry, whereas three-coordinated Sb atoms are in a pyramidal configuration. The tetrahedral-like geometries are similar to those of the crystalline phase of the two binary compounds GaTe and GaSb. A sizable fraction of Sb-Sb bonds is also present, indicating a partial nanoscale segregation of Sb. Despite the fact that the composition Ga4Sb6Te3 lies on the pseudobinary Ga Sb -Sb2Te3 tie line, the amorphous network can be seen as a mixture of the two binary compounds GaTe and GaSb with intertwined elemental Sb.

  7. High-voltage CMOS detectors

    NASA Astrophysics Data System (ADS)

    Ehrler, F.; Blanco, R.; Leys, R.; Perić, I.

    2016-07-01

    High-voltage CMOS (HVCMOS) pixel sensors are depleted active pixel sensors implemented in standard commercial CMOS processes. The sensor element is the n-well/p-substrate diode. The sensor electronics are entirely placed inside the n-well which is at the same time used as the charge collection electrode. High voltage is used to deplete the part of the substrate around the n-well. HVCMOS sensors allow implementation of complex in-pixel electronics. This, together with fast signal collection, allows a good time resolution, which is required for particle tracking in high energy physics. HVCMOS sensors will be used in Mu3e experiment at PSI and are considered as an option for both ATLAS and CLIC (CERN). Radiation tolerance and time walk compensation have been tested and results are presented.

  8. TRANSISTOR HIGH VOLTAGE POWER SUPPLY

    DOEpatents

    Driver, G.E.

    1958-07-15

    High voltage, direct current power supplies are described for use with battery powered nuclear detection equipment. The particular advantages of the power supply described, are increased efficiency and reduced size and welght brought about by the use of transistors in the circuit. An important feature resides tn the employment of a pair of transistors in an alternatefiring oscillator circuit having a coupling transformer and other circuit components which are used for interconnecting the various electrodes of the transistors.

  9. 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.

  10. E-beam high voltage switching power supply

    DOEpatents

    Shimer, Daniel W.; Lange, Arnold C.

    1997-01-01

    A high power, solid state power supply is described for producing a controllable, constant high voltage output under varying and arcing loads suitable for powering an electron beam gun or other ion source. The present power supply is most useful for outputs in a range of about 100-400 kW or more. The power supply is comprised of a plurality of discrete switching type dc-dc converter modules, each comprising a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, and an output rectifier for producing a dc voltage at the output of each module. The inputs to the converter modules are fed from a common dc rectifier/filter and are linked together in parallel through decoupling networks to suppress high frequency input interactions. The outputs of the converter modules are linked together in series and connected to the input of the transmission line to the load through a decoupling and line matching network. The dc-dc converter modules are phase activated such that for n modules, each module is activated equally 360.degree./n out of phase with respect to a successive module. The phased activation of the converter modules, combined with the square current waveforms out of the step up transformers, allows the power supply to operate with greatly reduced output capacitance values which minimizes the stored energy available for discharge into an electron beam gun or the like during arcing. The present power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle using simulated voltage feedback signals and voltage feedback loops. Circuitry is also provided for sensing incipient arc currents reflected at the output of the power supply and for simultaneously decoupling the power supply circuitry from the arcing load.

  11. E-beam high voltage switching power supply

    DOEpatents

    Shimer, D.W.; Lange, A.C.

    1997-03-11

    A high power, solid state power supply is described for producing a controllable, constant high voltage output under varying and arcing loads suitable for powering an electron beam gun or other ion source. The present power supply is most useful for outputs in a range of about 100-400 kW or more. The power supply is comprised of a plurality of discrete switching type dc-dc converter modules, each comprising a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, and an output rectifier for producing a dc voltage at the output of each module. The inputs to the converter modules are fed from a common dc rectifier/filter and are linked together in parallel through decoupling networks to suppress high frequency input interactions. The outputs of the converter modules are linked together in series and connected to the input of the transmission line to the load through a decoupling and line matching network. The dc-dc converter modules are phase activated such that for n modules, each module is activated equally 360{degree}/n out of phase with respect to a successive module. The phased activation of the converter modules, combined with the square current waveforms out of the step up transformers, allows the power supply to operate with greatly reduced output capacitance values which minimizes the stored energy available for discharge into an electron beam gun or the like during arcing. The present power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle using simulated voltage feedback signals and voltage feedback loops. Circuitry is also provided for sensing incipient arc currents reflected at the output of the power supply and for simultaneously decoupling the power supply circuitry from the arcing load. 7 figs.

  12. High-Voltage, Low-Power BNC Feedthrough Terminator

    NASA Technical Reports Server (NTRS)

    Bearden, Douglas

    2012-01-01

    This innovation is a high-voltage, lowpower BNC (Bayonet Neill-Concelman) feedthrough that enables the user to terminate an instrumentation cable properly while connected to a high voltage, without the use of a voltage divider. This feedthrough is low power, which will not load the source, and will properly terminate the instrumentation cable to the instrumentation, even if the cable impedance is not constant. The Space Shuttle Program had a requirement to measure voltage transients on the orbiter bus through the Ground Lightning Measurement System (GLMS). This measurement has a bandwidth requirement of 1 MHz. The GLMS voltage measurement is connected to the orbiter through a DC panel. The DC panel is connected to the bus through a nonuniform cable that is approximately 75 ft (approximately equal to 23 m) long. A 15-ft (approximately equal to 5-m), 50-ohm triaxial cable is connected between the DC panel and the digitizer. Based on calculations and simulations, cable resonances and reflections due to mismatched impedances of the cable connecting the orbiter bus and the digitizer causes the output not to reflect accurately what is on the bus. A voltage divider at the DC panel, and terminating the 50-ohm cable properly, would eliminate this issue. Due to implementation issues, an alternative design was needed to terminate the cable properly without the use of a voltage divider. Analysis shows how the cable resonances and reflections due to the mismatched impedances of the cable connecting the orbiter bus and the digitizer causes the output not to reflect accurately what is on the bus. After simulating a dampening circuit located at the digitizer, simulations were performed to show how the cable resonances were dampened and the accuracy was improved significantly. Test cables built to verify simulations were accurate. Since the dampening circuit is low power, it can be packaged in a BNC feedthrough.

  13. Measurement of rf voltages on the plasma-touching surfaces of ICRF antennas

    SciTech Connect

    Hoffman, D.J.; Baity, F.W.; Bell, G.L.; Bigelow, T.S.; Caughman, J.B.O.; Goulding, R.H.; Haste, G.R.; Ryan, P.M.; Zhang, H.

    1995-09-01

    Measurements of the rf voltages on Faraday shields and protection bumpers have been made for several loop antennas, including the mock-up antenna and Al for JET, the original antenna for Tore Supra, the present ASDEX-U antenna, and the folded waveguide. The loop antennas show voltages that scale to {approx}12 kV for a maximum input voltage of 30 kV with 0/0 phasing. The voltages are dramatically reduced for 0/{pi} phasing. These voltages are significant in that they can substantially increase the rf sheath potential beyond the levels associated with the simple electromagnetic field linkage from the current straps that results in plasma heating. In this paper, we investigate and measure the source of these voltages, their scaling with antenna impedance, and the differences between the loop arrays.

  14. A PLL Scheme for Synchronization with Grid Voltage Phasor in Active Power Filter Systems

    NASA Astrophysics Data System (ADS)

    Krievs, Oskars; Steiks, Ingars; Ribickis, Leonids

    2010-01-01

    Voltage source inverters connected to the grid in applications such as active power filters require synchronization with the grid voltage. Since in practice the grid voltage can be unbalanced and distorted, but the operation of the whole active filter control system is strongly dependant on precise estimation of grid voltage phase, the fundamental positive sequence phasor of the grid voltage has to be extracted. In this paper a system for smooth estimation of the position of the voltage phasor at the point of common coupling of a parallel active filter system is presented using a sinusoidal signal integrator and a simple software PLL. The performance of the proposed system is verified by simulation and experimental results. The proposed PLL scheme can also be used in other vector oriented control systems.

  15. High voltage compliance constant current ballast

    NASA Technical Reports Server (NTRS)

    Rosenthal, L. A.

    1976-01-01

    A ballast circuit employing a constant current diode and a vacuum tube that can provide a constant current over a voltage range of 1000 volts. The simple circuit can prove useful in studying voltage breakdown characteristics.

  16. Electrooptic polymer voltage sensor and method of manufacture thereof

    NASA Technical Reports Server (NTRS)

    Gottsche, Allan (Inventor); Perry, Joseph W. (Inventor)

    1993-01-01

    An optical voltage sensor utilizing an electrooptic polymer is disclosed for application to electric power distribution systems. The sensor, which can be manufactured at low cost in accordance with a disclosed method, measures voltages across a greater range than prior art sensors. The electrooptic polymer, which replaces the optical crystal used in prior art sensors, is sandwiched directly between two high voltage electrodes. Voltage is measured by fiber optical means, and no voltage division is required. The sample of electrooptic polymer is fabricated in a special mold and later mounted in a sensor housing. Alternatively, mold and sensor housing may be identical. The sensor housing is made out of a machinable polymeric material and is equipped with two opposing optical windows. The optical windows are mounted in the bottom of machined holes in the wall of the mold. These holes provide for mounting of the polarizing optical components and for mounting of the fiber optic connectors. One connecting fiber is equipped with a light emitting diode as a light source. Another connecting fiber is equipped with a photodiode as a detector.

  17. High-voltage discharge in supersonic jet of plumbum vapor

    NASA Astrophysics Data System (ADS)

    Amirov, R. Kh; Antonov, N. N.; Liziakin, G. D.; Polistchook, V. P.; Samoylov, I. S.; Usmanov, R. A.; Yartsev, I. M.

    2015-11-01

    During study of vacuum discharge in plumbum evaporating from molybdenum crucible in identical geometry of discharge gap and the same crucible temperature existence of two different discharge forms were observed. These two forms are vacuum arc with current above 10 A and voltage about 15 V and high-voltage discharge with current about 10 mA and voltage of 340 V. Plumbum was placed in heat-isolated crucible (cathode). Electron-beam heater was situated under the crucible. At the temperature of 1.25 kK that corresponds to plumbum saturated vapor pressure about 0.1 kPa voltage from power source (380 V, 200 A) was applied to anode and high-voltage discharge initiated with characteristics mentioned above. After a few seconds this discharge could turn into arc or could exist hundreds of seconds until total plumbum evaporation. Glow of discharge could take the form of a cone, harness or plasma bunch that hanged at the appreciable distance from the electrodes. The estimations of plasma parameters are presented.

  18. Analysing the thermal state of voltage transformer based on resistive voltage divider

    NASA Astrophysics Data System (ADS)

    Lebedev, V.; Zhukov, V.; Yablokov, A.

    2015-10-01

    We performed a simulation of the thermal state of a resistive voltage divider based on an equation of heat conductivity with internal sources of heat, solving this equation by using two numerical procedures. We also conducted experimental research regarding transformer thermal state on a laboratory stand. We obtained numerical results of the above heat conductivity equation, taking into account the supply of heat energy from internal sources, and compared the results of our calculations with our experimental data. Transformer thermal state simulation and numerical solution procedures enable us to formulate and resolve the problems of choosing optimal transformer design and operating modes, ensuring maximum measuring accuracy when limiting the thermal state of resistive elements.

  19. A tunable CMOS constant current source

    NASA Technical Reports Server (NTRS)

    Thelen, D.

    1991-01-01

    A constant current source has been designed which makes use of on chip electrically erasable memory to adjust the magnitude and temperature coefficient of the output current. The current source includes a voltage reference based on the difference between enhancement and depletion transistor threshold voltages. Accuracy is +/- 3% over the full range of power supply, process variations, and temperature using eight bits for tuning.

  20. Driver circuit for solid state light sources

    DOEpatents

    Palmer, Fred; Denvir, Kerry; Allen, Steven

    2016-02-16

    A driver circuit for a light source including one or more solid state light sources, a luminaire including the same, and a method of so driving the solid state light sources are provided. The driver circuit includes a rectifier circuit that receives an alternating current (AC) input voltage and provides a rectified AC voltage. The driver circuit also includes a switching converter circuit coupled to the light source. The switching converter circuit provides a direct current (DC) output to the light source in response to the rectified AC voltage. The driver circuit also includes a mixing circuit, coupled to the light source, to switch current through at least one solid state light source of the light source in response to each of a plurality of consecutive half-waves of the rectified AC voltage.

  1. Study on the Formation and Precipitation Mechanism of Mn5Si3 Phase in the MBA-2 Brass Alloy

    NASA Astrophysics Data System (ADS)

    Li, Hang; Jie, Jinchuan; Zhang, Pengchao; Jia, Chunxu; Wang, Tongmin; Li, Tingju

    2016-06-01

    Mn5Si3 is an attractive dispersion in the special brass, owing to its high hardness and high wear resistance. In the present study, synchrotron X-ray radiography and rapid cooling were applied to investigate the formation mechanism of Mn5Si3 phase in the MBA-2 brass alloy. The primary Mn5Si3 phase is proved to exist stably in the alloy melt and nucleate from the melt at temperatures above 1373 K (1100 °C). In addition, the precipitation mechanism of Mn5Si3 phase is addressed systematically by the isothermal heat treatment. The Mn5Si3 particles are observed to precipitate from the matrix at temperatures above 1023 K (750 °C), and a crystallographic orientation relationship is found between the precipitated Mn5Si3 particle and β phase: (110)_{β } //(1overline{1} 00)_{{{{Mn}}5 {{Si}}3 }} and [overline{1} 11]_{β } //[11overline{2} overline{2} ]_{{{{Mn}}5 {{Si}}3 }} . However, the precipitation of Mn5Si3 phase is thermodynamically inhibited at lower temperatures, which can be ascribed to the increase in the Gibbs free energy of formation of Mn5Si3 with decreasing the temperature.

  2. Voltage-Gated Sodium Channels

    NASA Astrophysics Data System (ADS)

    Hanck, Dorothy A.; Fozzard, Harry A.

    Voltage-gated sodium channels subserve regenerative excitation throughout the nervous system, as well as in skeletal and cardiac muscle. This excitation results from a voltage-dependent mechanism that increases regeneratively and selectively the sodium conductance of the channel e-fold for a 4-7 mV depolarization of the membrane with time constants in the range of tens of microseconds. Entry of Na+ into the cell without a companion anion depolarizes the cell. This depolarization, called the action potential, is propagated at rates of 1-20 meters/sec. In nerve it subserves rapid transmission of information and, in muscle cells, coordinates the trigger for contraction. Sodium-dependent action potentials depolarize the membrane to inside positive values of about 30-40 mV (approaching the electrochemical potential for the transmembrane sodium gradient). Repolarization to the resting potential (usually between -60 and -90 mV) occurs because of inactivation (closure) of sodium channels, which is assisted in different tissues by variable amounts of activation of voltage-gated potassium channels. This sequence results in all-or-nothing action potentials in nerve and fast skeletal muscle of 1-2 ms duration, and in heart muscle of 100-300 ms duration. Recovery of regenerative excitation, i.e., recovery of the ability of sodium channels to open, occurs after restoration of the resting potential with time constants of a few to several hundreds of milliseconds, depending on the channel isoform, and this rate controls the minimum interval for repetitive action potentials (refractory period).

  3. Piezo Voltage Controlled Planar Hall Effect Devices

    NASA Astrophysics Data System (ADS)

    Zhang, Bao; Meng, Kang-Kang; Yang, Mei-Yin; Edmonds, K. W.; Zhang, Hao; Cai, Kai-Ming; Sheng, Yu; Zhang, Nan; Ji, Yang; Zhao, Jian-Hua; Zheng, Hou-Zhi; Wang, Kai-You

    2016-06-01

    The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the piezo voltage controlled Co2FeAl planar Hall effect devices without the external magnetic field. Our demonstration may lead to the realization of both information storage and processing using ferromagnetic materials.

  4. Piezo Voltage Controlled Planar Hall Effect Devices.

    PubMed

    Zhang, Bao; Meng, Kang-Kang; Yang, Mei-Yin; Edmonds, K W; Zhang, Hao; Cai, Kai-Ming; Sheng, Yu; Zhang, Nan; Ji, Yang; Zhao, Jian-Hua; Zheng, Hou-Zhi; Wang, Kai-You

    2016-06-22

    The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the piezo voltage controlled Co2FeAl planar Hall effect devices without the external magnetic field. Our demonstration may lead to the realization of both information storage and processing using ferromagnetic materials.

  5. VOLTAGE-CONTROLLED TRANSISTOR OSCILLATOR

    DOEpatents

    Scheele, P.F.

    1958-09-16

    This patent relates to transistor oscillators and in particular to those transistor oscillators whose frequencies vary according to controlling voltages. A principal feature of the disclosed transistor oscillator circuit resides in the temperature compensation of the frequency modulating stage by the use of a resistorthermistor network. The resistor-thermistor network components are selected to have the network resistance, which is in series with the modulator transistor emitter circuit, vary with temperature to compensate for variation in the parameters of the transistor due to temperature change.

  6. High voltage RF feedthrough bushing

    DOEpatents

    Grotz, Glenn F.

    1984-01-01

    Described is a multi-element, high voltage radio frequency bushing for trmitting RF energy to an antenna located in a vacuum container. The bushing includes a center conductor of complex geometrical shape, an outer coaxial shield conductor, and a thin-walled hollow truncated cone insulator disposed between central and outer conductors. The shape of the center conductor, which includes a reverse curvature portion formed of a radially inwardly directed shoulder and a convex portion, controls the uniformity of the axial surface gradient on the insulator cone. The outer shield has a first substantially cylindrical portion and a second radially inwardly extending truncated cone portion.

  7. Low Voltage Silicon Dioxide Reliability

    NASA Astrophysics Data System (ADS)

    Schuegraf, Klaus Florian

    This study investigates the low voltage breakdown and conduction properties of thin thermal silicon dioxides with thickness ranging from 25 A to 130 A using silicon metal-oxide-semiconductor (MOS) capacitors and transistors. Investigation of oxide breakdown shows that anode hole injection is the likely mechanism responsible for silicon dioxide wearout. A quantitative model for oxide breakdown based on anode hole injection is proposed. This model not only agrees with the predictions of an empirical inverse oxide field model ("1 over E model"), it offers a methodology to extrapolate high field oxide breakdown data into the low voltage operating regime. Investigation of low voltage silicon dioxide tunneling current shows that leakage current increases dramatically above that predicted by the Fowler-Nordheim theory for oxide voltages less than 3.15 Volts, possibly setting a scaling limit on thickness at 40 A. The model is also used to compare the breakdown of p^+ and n^+ polysilicon gate, showing no change in damage initiation mechanism. The temperature dependence of breakdown is also investigated, showing that anode hole injection models the breakdown characteristics accurately for temperatures below 150^circC. The temperature acceleration of breakdown is attributed to the oxide's reduced hole immunity at higher temperatures. The anode hole injection model is thereby shown to model the breakdown characteristics of defect-free, "intrinsic" oxide very accurately. A defect model combining the breakdown mechanism of anode hole injection with "effective thinning" is able to characterize defect breakdown distributions by attributing the breakdown to an effective thinning of the oxide at some localized point. Substrate current measurements during electrical breakdown stress establish the basis for the anode hole injection model. Investigations of substrate current in oxides thinner than 55 A show that the anode hole injection current becomes dominated by the tunneling of

  8. High Voltage TAL Erosion Characterization

    NASA Technical Reports Server (NTRS)

    Jacobson, David T.

    2003-01-01

    Extended operation of a D-80 anode layer thruster at high voltage was investigated. The thruster was operated for 1200 hours at 700 Volts and 4 Amperes. Laser profilometry was employed to quantify the erosion of the thruster's graphite guard rings and electrodes at 0, 300, 600, 900, and 1200 hours. Thruster performance and electrical characteristics were monitored over the duration of the investigation. The guard rings exhibited asymmetric erosion that was greatest in the region of the cathode. Erosion of the guard rings exposed the magnet poles between 600 to 900 hours of operation.

  9. 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.

  10. 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.

  11. Rapid and precise measurement of flatband voltage

    NASA Technical Reports Server (NTRS)

    Li, S. P.; Ryan, M.; Bates, E. T.

    1976-01-01

    The paper outlines the design, principles of operation, and calibration of a five-IC network intended to give a rapid, precise, and automatic determination of the flatband voltage of MOS capacitors. The basic principle of measurement is to compare the analog output voltage of a capacitance meter - which is directly proportional to the capacitance being measured - with a preset or dialed-in voltage proportional to the calculated flatband capacitance by means of a comparator circuit. The bias to the MOS capacitor supplied through the capacitance meter is provided by a ramp voltage going from a negative toward a positive voltage level and vice versa. The network employs two monostable multivibrators for reading and recording the flatband voltage and for resetting the initial conditions and restarting the ramp. The flatband voltage can be held and read on a digital voltmeter.

  12. 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.

  13. 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.

  14. 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

  15. Association of residential magnetic fields with contact voltage.

    PubMed

    Kavet, Robert; Zaffanella, Luciano E; Pearson, Robert L; Dallapiazza, John

    2004-10-01

    The US National Electrical Code's (NEC) requirement to ground a home's electrical service to the residential water line results in a voltage between the water line and earth, V W-E. The voltage may result from ground return current that flows into the earth via the water line or from inductive effects from other sources of magnetic fields, such as transmission lines. This voltage can, in turn, serve as a source for Vbath, the voltage between the water fixtures and conductive drain pipes sunk into the earth beneath a residence. Vbath can be a source of contact current exposure to a child touching a water fixture while bathing. Previous research has suggested that exposure to these currents could be the basis for the association between power-frequency magnetic fields and childhood leukemia. In this study, we assessed the association between measured Vbath and VW-E with the average spot-measured magnetic field, Bavg, in a sample of 191 single-family residences in the Denver metropolitan area. This area was the source of cases and controls for previous studies of electric and magnetic field (EMF) and childhood cancer. The association of both Vbath and VW-E with Bavg had upward trends across magnetic field strata (<0.1 microT (reference); 0.1-<0.3 microT; and > or = 0.3 microT). In addition, VW-E was associated with Vbath. Without further study, these results cannot be applied to multi-dwelling residences or to electrical systems prevalent in other nations. Nonetheless, when combined with the finding that contact current is a far more plausible candidate than the residential magnetic field for mediating biological effects on the basis of comparative dose to bone marrow, these associations indicate that contact current exposure deserves further study.

  16. Development of a one-chip quantized Hall resistance voltage divider

    NASA Astrophysics Data System (ADS)

    Domae, Atsushi; Oe, Takehiko; Matsuhiro, Kenjiro; Kiryu, Syogo; Kaneko, Nobu-hisa

    2012-12-01

    A resistive voltage divider, which is constructed from a binary segmented series array of quantized Hall resistance (QHR) bars fabricated on one chip, named the ‘QHR voltage divider’, has been developed. The QHR voltage divider does not, in principle, require time-consuming bootstrap self-calibration and will provide voltage ratios that are defined by fundamental physical constants with small uncertainties. To evaluate the performance of the QHR voltage divider, the dependence of the Hall resistances RH of all serial segments on the magnetic flux density was measured. The results of the RH measurement showed large and well-defined plateaus, and it was confirmed that the fabricated QHR divider in conjunction with a suitable voltage source would function as a voltage divider. From a preliminary test of the voltage ratios of the QHR voltage divider, deviations from nominal ratios were measured to be less than 1.4 × 10-6, and the expanded uncertainty of the measurement was estimated to be less than 4.1 × 10-6.

  17. Biased low differential input impedance current receiver/converter device and method for low noise readout from voltage-controlled detectors

    DOEpatents

    Degtiarenko, Pavel V.; Popov, Vladimir E.

    2011-03-22

    A first stage electronic system for receiving charge or current from voltage-controlled sensors or detectors that includes a low input impedance current receiver/converter device (for example, a transimpedance amplifier), which is directly coupled to the sensor output, a source of bias voltage, and the device's power supply (or supplies), which use the biased voltage point as a baseline.

  18. Peristaltic ion source

    SciTech Connect

    Brown, I.G.; Anders, A.; Anders, S.; Dickinson, M.R.; MacGill, R.A.

    1995-08-01

    Conventional ion sources generate energetic ion beams by accelerating the plasma-produced ions through a voltage drop at the extractor, and since it is usual that the ion beam is to propagate in a space which is at ground potential, the plasma source is biased at extractor voltage. For high ion beam energy the plasma source and electrical systems need to be raised to high voltage, a task that adds considerable complexity and expense to the total ion source system. The authors have developed a system which though forming energetic ion beams at ground potential as usual, operates with the plasma source and electronics at ground potential also. Plasma produced by a nearby source streams into a grided chamber that is repetitively pulsed from ground to high positive potential, sequentially accepting plasma into its interior region and ejecting it energetically. They call the device a peristaltic ion source. In preliminary tests they`ve produced nitrogen and titanium ion beams at energies from 1 to 40 keV. Here they describe the philosophy behind the approach, the test embodiment that they have made, and some preliminary results.

  19. 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.

  20. High voltage load resistor array

    DOEpatents

    Lehmann, Monty Ray

    2005-01-18

    A high voltage resistor comprising an array of a plurality of parallel electrically connected resistor elements each containing a resistive solution, attached at each end thereof to an end plate, and about the circumference of each of the end plates, a corona reduction ring. Each of the resistor elements comprises an insulating tube having an electrode inserted into each end thereof and held in position by one or more hose clamps about the outer periphery of the insulating tube. According to a preferred embodiment, the electrode is fabricated from stainless steel and has a mushroom shape at one end, that inserted into the tube, and a flat end for engagement with the end plates that provides connection of the resistor array and with a load.

  1. High voltage feed through bushing

    DOEpatents

    Brucker, J.P.

    1993-04-06

    A feed through 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. Modelling of macrosegregation in direct chill casting considering columnar-to-equiaxed transition using 3-phase Eulerian approach

    NASA Astrophysics Data System (ADS)

    Hao, J.; Lin, Y. J.; Nie, Y.; Wu, M.; Ludwig, A.

    2015-06-01

    A 3-phase Eulerian approach is used to model the macrosegregation during solidification in direct chill (DC) casting of binary bronze (Cu-Sn). The three phases are the melt, the solidifying columnar dendrites and the equiaxed grains. The thermodynamic information of Cu-Sn is included based on published thermodynamic data, which are coupled with the 3-phase solidification model. The occurrence of columnar-to-equiaxed transition (CET), phase interactions, feeding flow, equiaxed sedimentation and their influence on macrosegregation are considered in the model. The model is applied to a laboratory DC casting process of bronze as a benchmark to demonstrate the model potentials. The simulation results of mixed columnar and equiaxed solidification as well as the formation of macrosegregation are presented. The focus of this work is to analyze and discuss the macrosegregation mechanisms by different flow including feeding flow and crystal sedimentation.

  3. 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.

  4. Cooperative Voltage Control Method by Power Factor Control of PV Systems and LRT

    NASA Astrophysics Data System (ADS)

    Kawasaki, Shoji; Kanemoto, Noriaki; Taoka, Hisao; Matsuki, Junya; Hayashi, Yasuhiro

    Recently, the number of system interconnection of the renewable energy sources (RES) such as the photovoltaic generation (PV) and wind power generation is increasing drastically, and there is in danger of changing the voltages in a distribution system by the precipitous output variation of RESs. In this study, the authors propose one voltage control method of the distribution system by the power factor control of plural PV systems in consideration of cooperation with the load ratio control transformer (LRT) of laggard control response installed beforehand in the distribution system. In the proposed method, the slow voltage variation is controlled by LRT, and the steep voltage variation uncontrollable by LRT is controlled by plural PV systems, as a result, all the node voltages are controllable within the proper limits. In order to verify the validity of the proposed method, the numerical calculations are carried out by using an analytical model of distribution system which interconnected PV systems.

  5. Programable Driver for Voltage-Controlled Oscillators

    NASA Technical Reports Server (NTRS)

    Fowler, L. E.; Mcneil, J. A.

    1985-01-01

    Electronically programable read-only memory (EPROM) and digital-to-analog converter provide customized time-varying voltage for frequency modulation. Voltage used to modulate IMPATT oscillator that serves as microwave pump for solid-state maser in low-noise amplifier. EPROM simple to tailor voltage waveform to suit characteristics of given maser. Digital information for waveform programed into EPROM chip; digital-to-analog converter reads information and produces corresponding analog wave. Principle readily adapted to other applications.

  6. Electro-Optical High-Voltage Sensors

    NASA Technical Reports Server (NTRS)

    Gottsche, Allan; Johnston, Alan R.

    1992-01-01

    Electro-optical sensors for measuring high voltages developed for use in automatically controlled power-distribution systems. Sensors connected to optoelectronic interrogating equipment by optical fibers. Because sensitive material and optical fibers are all dielectric, no problem in electrically isolating interrogating circuitry from high voltage, and no need for voltage dividers. Sensor signals transmitted along fibers immune to electromagnetic noise at radio and lower frequencies.

  7. High-Voltage CMOS Controller for Microfluidics.

    PubMed

    Khorasani, M; Behnam, M; van den Berg, L; Backhouse, C J; Elliott, D G

    2009-04-01

    A high-voltage microfluidic controller designed using DALSA semiconductor's 0.8-mum low-voltage/high-voltage complementary metal-oxide semiconductor/double diffused metal-oxide semiconductor process is presented. The chip's four high-voltage output drivers can switch 300 V, and the dc-dc boost converter can generate up to 68 V using external passive components. This integrated circuit represents an advancement in microfluidic technology when used in conjunction with a charge coupling device (CCD)-based optical system and a glass microfluidic channel, enabling a portable and cost-efficient platform for genetic analysis.

  8. Multijunction high voltage concentrator solar cells

    NASA Technical Reports Server (NTRS)

    Valco, G. J.; Kapoor, V. J.; Evans, J. C.; Chai, A.-T.

    1981-01-01

    The standard integrated circuit technology has been developed to design and fabricate new innovative planar multi-junction solar cell chips for concentrated sunlight applications. This 1 cm x 1 cm cell consisted of several voltage generating regions called unit cells which were internally connected in series within a single chip resulting in high open circuit voltages. Typical open-circuit voltages of 3.6 V and short-circuit currents of 90 ma were obtained at 80 AM1 suns. A dramatic increase in both short circuit current and open circuit voltage with increased light levels was observed.

  9. 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.

  10. Proton-exchanged optical waveguides in LiTaO3: phase composition and stress

    NASA Astrophysics Data System (ADS)

    Kuneva, M.; Christova, K.; Tonchev, S.

    2012-12-01

    Planar optical waveguide layers were obtained in Z-cut LiTaO3 crystal substrates via proton exchange. Two different media were used as proton sources: benzoic acid melt and lithium hydrogensulphate vapors, controlling the thickness of the waveguides by duration and temperature of the proton exchange process and also by post-exchange annealing. The intrinsic stress caused by the penetration of the hydrogen ions into the crystal lattice was estimated by the optical integral method. The phase composition of proton-exchanged layers was analyzed based on the mode and IR-absorption spectra. An attempt to relate the level of stress to the level of proton doping has been made.

  11. Thermally-induced voltage alteration for analysis of microelectromechanical devices

    DOEpatents

    Walraven, Jeremy A.; Cole, Jr., Edward I.

    2002-01-01

    A thermally-induced voltage alteration (TIVA) apparatus and method are disclosed for analyzing a microelectromechanical (MEM) device with or without on-board integrated circuitry. One embodiment of the TIVA apparatus uses constant-current biasing of the MEM device while scanning a focused laser beam over electrically-active members therein to produce localized heating which alters the power demand of the MEM device and thereby changes the voltage of the constant-current source. This changing voltage of the constant-current source can be measured and used in combination with the position of the focused and scanned laser beam to generate an image of any short-circuit defects in the MEM device (e.g. due to stiction or fabrication defects). In another embodiment of the TIVA apparatus, an image can be generated directly from a thermoelectric potential produced by localized laser heating at the location of any short-circuit defects in the MEM device, without any need for supplying power to the MEM device. The TIVA apparatus can be formed, in part, from a scanning optical microscope, and has applications for qualification testing or failure analysis of MEM devices.

  12. Effects of voltage errors caused by gap-voltage and automatic-frequency tuning in an alternating-phase-focused linac

    NASA Astrophysics Data System (ADS)

    Iwata, Y.; Yamada, S.; Murakami, T.; Fujimoto, T.; Fujisawa, T.; Ogawa, H.; Miyahara, N.; Yamamoto, K.; Hojo, S.; Sakamoto, Y.; Muramatsu, M.; Takeuchi, T.; Mitsumoto, T.; Tsutsui, H.; Watanabe, T.; Ueda, T.

    2008-05-01

    A compact injector for a heavy-ion medical-accelerator complex was developed. It consists of an electron-cyclotron-resonance ion-source (ECRIS) and two linacs, which are a radio-frequency-quadrupole (RFQ) linac and an Interdigital H-mode drift-tube-linac (IH-DTL). Beam acceleration tests of the compact injector were performed, and the designed beam quality was verified by the measured results, as reported earlier. Because the method of alternating-phase-focusing (APF) was used for beam focusing of the IH-DTL, the motion of beam ions would be sensitive to gap-voltage errors, caused during tuning of the gap-voltage distribution and by automatic-frequency tuning in actual operation. To study the effects of voltage errors to beam quality, further measurements were performed during acceleration tests. In this report, the effects of voltage errors for the APF IH-DTL are discussed.

  13. A novel series connected batteries state of high voltage safety monitor system for electric vehicle application.

    PubMed

    Jiaxi, Qiang; Lin, Yang; Jianhui, He; Qisheng, Zhou

    2013-01-01

    Batteries, as the main or assistant power source of EV (Electric Vehicle), are usually connected in series with high voltage to improve the drivability and energy efficiency. Today, more and more batteries are connected in series with high voltage, if there is any fault in high voltage system (HVS), the consequence is serious and dangerous. Therefore, it is necessary to monitor the electric parameters of HVS to ensure the high voltage safety and protect personal safety. In this study, a high voltage safety monitor system is developed to solve this critical issue. Four key electric parameters including precharge, contact resistance, insulation resistance, and remaining capacity are monitored and analyzed based on the equivalent models presented in this study. The high voltage safety controller which integrates the equivalent models and control strategy is developed. By the help of hardware-in-loop system, the equivalent models integrated in the high voltage safety controller are validated, and the online electric parameters monitor strategy is analyzed and discussed. The test results indicate that the high voltage safety monitor system designed in this paper is suitable for EV application.

  14. Application of Microsecond Voltage Pulses for Water Disinfection by Diaphragm Electric Discharge

    NASA Astrophysics Data System (ADS)

    Kakaurov, S. V.; Suvorov, I. F.; Yudin, A. S.; Solovyova, T. L.; Kuznetsova, N. S.

    2015-11-01

    The paper presents the dependence of copper and silver ions formation on the duration of voltage pulses of diaphragm electric discharge and on the pH of treated liquid medium. Knowing it allows one to create an automatic control system to control bactericidal agent's parameters obtained in diaphragm electric discharge reactor. The current-voltage characteristic of the reactor with a horizontal to the diaphragm membrane water flow powered from the author's custom pulse voltage source is also presented. The results of studies of the power consumption of diaphragm electric discharge depending on temperature of the treated liquid medium are given.

  15. Voltage divider operation using high-Tc superconducting interface-engineered Josephson junctions

    NASA Astrophysics Data System (ADS)

    Saitoh, Kazuo; Soutome, Yoshihisa; Fukazawa, Tokuumi; Tarutani, Yoshinobu; Takagi, Kazumasa

    2000-05-01

    A rapid-single-flux-quantum toggle-flip-flop logic gate was fabricated using high-temperature superconducting interface-engineered Josephson junctions. It was shown that the gate can operate as a voltage divider up to 155 GHz at 15 K and 19 GHz at 27 K. At the same time, the temperature dependence of the IcRn product and the maximum divided voltage was compared. As a result, it was found that the ratio of these values is 0.4-0.1 for 15 K>T>27 K. Circuit simulation with noise sources reveals this peculiar temperature dependence of the maximum divided voltage.

  16. Voltage-dependent membrane displacements measured by atomic force microscopy.

    PubMed

    Mosbacher, J; Langer, M; Hörber, J K; Sachs, F

    1998-01-01

    Cells use polar molecules in the membrane to sense changes in the transmembrane potential. The opening of voltage-gated ion channels and membrane bending due to the inverse flexoelectric effect are two examples of such electromechanical coupling. We have looked for membrane motions in an electric field using atomic (or scanning) force microscopy (AFM) with the intent of studying voltage-dependent conformational changes of ion channels. Voltage-clamped HEK293 cells were either untransfected controls or transfected with Shaker K+ channels. Using a +/- 10-mV peak-peak AC carrier stimulus, untransfected cells moved 0.5-15 nm normal to the plane of the membrane. These movements tracked the voltage at frequencies >1 kHz with a phase lead of 60-120 degrees, as expected of a displacement current. The movement was outward with depolarization, but the holding potential only weakly influenced the amplitude of the movement. In contrast, cells transfected with a noninactivating mutant of Shaker K+channels showed similar movements, but these were sensitive to the holding potential; decreasing with depolarization between -80 and 0 mV. Searching for artifactual origins of these movements, we used open or sealed pipettes and AFM cantilever placements just above the cells. These results were negative, suggesting that the observed movements were produced by the cell membrane rather than by movement of the patch pipette, or by acoustic or electrical interactions of the membrane with the AFM tip. In control cells, the electrical motor may arise from the flexoelectric effect, where changes in potential induce changes in curvature. In transfected cells, it appears that channel-specific movements also occurred. These experiments demonstrate that the AFM may be able to exploit voltage-dependent movements as a source of contrast for imaging membrane components. The electrically induced motility will cause twitching during action potentials, and may have physiological consequences. PMID

  17. Steep front short duration low voltage impulse performance of distribution transformers

    SciTech Connect

    Burrage, L.M.; Veverka, E.F.; McConnell, B.W.

    1987-01-01

    An extensive literature search of steep front short duration (SFSD) impulse sources, their characteristics and effect on power system equipment has led to the specification of a test program to evaluate key apparatus and insulations. Distribution transformers, although not overly susceptible to impulse damage, have been selected as one of the candidate apparatus for low and high voltage SFSD impulse tests. This paper covers the low voltage SFSD impulse response of conventional oil insulated shell form and core form distribution transformers.

  18. Wide-range voltage modulation

    SciTech Connect

    Rust, K.R.; Wilson, J.M.

    1992-06-01

    The Superconducting Super Collider`s Medium Energy Booster Abort (MEBA) kicker modulator will supply a current pulse to the abort magnets which deflect the proton beam from the MEB ring into a designated beam stop. The abort kicker will be used extensively during testing of the Low Energy Booster (LEB) and the MEB rings. When the Collider is in full operation, the MEBA kicker modulator will abort the MEB beam in the event of a malfunction during the filling process. The modulator must generate a 14-{mu}s wide pulse with a rise time of less than 1 {mu}s, including the delay and jitter times. It must also be able to deliver a current pulse to the magnet proportional to the beam energy at any time during ramp-up of the accelerator. Tracking the beam energy, which increases from 12 GeV at injection to 200 GeV at extraction, requires the modulator to operate over a wide range of voltages (4 kV to 80 kV). A vacuum spark gap and a thyratron have been chosen for test and evaluation as candidate switches for the abort modulator. Modulator design, switching time delay, jitter and pre-fire data are presented.

  19. Voltage regulation in linear induction accelerators

    DOEpatents

    Parsons, W.M.

    1992-12-29

    Improvement in voltage regulation in a linear induction accelerator wherein a varistor, such as a metal oxide varistor, is placed in parallel with the beam accelerating cavity and the magnetic core is disclosed. The non-linear properties of the varistor result in a more stable voltage across the beam accelerating cavity than with a conventional compensating resistance. 4 figs.

  20. Voltage regulation in linear induction accelerators

    DOEpatents

    Parsons, William M.

    1992-01-01

    Improvement in voltage regulation in a Linear Induction Accelerator wherein a varistor, such as a metal oxide varistor, is placed in parallel with the beam accelerating cavity and the magnetic core. The non-linear properties of the varistor result in a more stable voltage across the beam accelerating cavity than with a conventional compensating resistance.

  1. 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.

  2. Would You Believe...? The Concept of Voltage.

    ERIC Educational Resources Information Center

    Iona, Mario

    1983-01-01

    Because voltage is a difficult concept to comprehend, it is expected that textbook authors would be clear/consistent in their presentation. Presents 11 examples in which the concept is explained or used (taken from one book), suggesting that the presentation makes it difficult for students to develop an understanding of voltage. (JN)

  3. A new very high voltage semiconductor switch

    NASA Technical Reports Server (NTRS)

    Sundberg, G. R.

    1985-01-01

    A new family of semiconductor switches using double injection techniques and compensated deep impurities is described. They have the potential to raise switching voltages a factor of 10 higher (up to 100 kV) than p-n junction devices while exhibiting extremely low (or zero) forward voltage. Several potential power switching applications are indicated.

  4. BANSHEE: High-voltage repetitively pulsed electron-beam driver

    SciTech Connect

    VanHaaften, F.

    1992-01-01

    BANSHEE (Beam Accelerator for a New Source of High-Energy Electrons) this is a high-voltage modulator is used to produce a high-current relativistic electron beam for high-power microwave tube development. The goal of the BANSHEE research is first to achieve a voltage pulse of 700--750 kV with a 1-{mu}s pulse width driving a load of {approximately}100 {Omega}, the pulse repetition frequency (PRF) of a few hertz. The ensuing goal is to increase the pulse amplitude to a level approaching 1 MV. We conducted tests using half the modulator with an output load of 200 {Omega}, up to a level of {approximately}650 kV at a PRF of 1 Hz and 525 kV at a PRF of 5 Hz. We then conducted additional testing using the complete system driving a load of {approximately}100 {Omega}.

  5. BANSHEE: High-voltage repetitively pulsed electron-beam driver

    SciTech Connect

    VanHaaften, F.

    1992-08-01

    BANSHEE (Beam Accelerator for a New Source of High-Energy Electrons) this is a high-voltage modulator is used to produce a high-current relativistic electron beam for high-power microwave tube development. The goal of the BANSHEE research is first to achieve a voltage pulse of 700--750 kV with a 1-{mu}s pulse width driving a load of {approximately}100 {Omega}, the pulse repetition frequency (PRF) of a few hertz. The ensuing goal is to increase the pulse amplitude to a level approaching 1 MV. We conducted tests using half the modulator with an output load of 200 {Omega}, up to a level of {approximately}650 kV at a PRF of 1 Hz and 525 kV at a PRF of 5 Hz. We then conducted additional testing using the complete system driving a load of {approximately}100 {Omega}.

  6. 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.

  7. Corona and Motor Voltage Interim Report

    SciTech Connect

    Hsu, J.S.

    2005-05-06

    It has been suggested that to meet the FreedomCAR objectives for cost, size, weight, efficiency, and reliability higher buss voltages be utilized in HEV and FC automotive applications. The reasoning is that since electric power is equal to the product of voltage and current for a given power a higher voltage and lower current would result in smaller cable and inverter switching components. Consequently, the system can be lighter and smaller. On the other hand, higher voltages are known to require better and thicker electrical insulation that reduce the available slot area for motor windings. One cause of slow insulation breakdown is corona that gradually erodes the insulation and shortens the life expectancy of the motor. This study reports on the results of a study on corona initiating voltages for mush-wound and bobbin-wound stators. A unique testing method is illustrated.

  8. Voltage collapse in complex power grids

    PubMed Central

    Simpson-Porco, John W.; Dörfler, Florian; Bullo, Francesco

    2016-01-01

    A large-scale power grid's ability to transfer energy from producers to consumers is constrained by both the network structure and the nonlinear physics of power flow. Violations of these constraints have been observed to result in voltage collapse blackouts, where nodal voltages slowly decline before precipitously falling. However, methods to test for voltage collapse are dominantly simulation-based, offering little theoretical insight into how grid structure influences stability margins. For a simplified power flow model, here we derive a closed-form condition under which a power network is safe from voltage collapse. The condition combines the complex structure of the network with the reactive power demands of loads to produce a node-by-node measure of grid stress, a prediction of the largest nodal voltage deviation, and an estimate of the distance to collapse. We extensively test our predictions on large-scale systems, highlighting how our condition can be leveraged to increase grid stability margins. PMID:26887284

  9. Flexible method for monitoring fuel cell voltage

    DOEpatents

    Mowery, Kenneth D.; Ripley, Eugene V.

    2002-01-01

    A method for equalizing the measured voltage of each cluster in a fuel cell stack wherein at least one of the clusters has a different number of cells than the identical number of cells in the remaining clusters by creating a pseudo voltage for the different cell numbered cluster. The average cell voltage of the all of the cells in the fuel cell stack is calculated and multiplied by a constant equal to the difference in the number of cells in the identical cell clusters and the number of cells in the different numbered cell cluster. The resultant product is added to the actual voltage measured across the different numbered cell cluster to create a pseudo voltage which is equivalent in cell number to the number of cells in the other identical numbered cell clusters.

  10. Piezo Voltage Controlled Planar Hall Effect Devices

    PubMed Central

    Zhang, Bao; Meng, Kang-Kang; Yang, Mei-Yin; Edmonds, K. W.; Zhang, Hao; Cai, Kai-Ming; Sheng, Yu; Zhang, Nan; Ji, Yang; Zhao, Jian-Hua; Zheng, Hou-Zhi; Wang, Kai-You

    2016-01-01

    The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the piezo voltage controlled Co2FeAl planar Hall effect devices without the external magnetic field. Our demonstration may lead to the realization of both information storage and processing using ferromagnetic materials. PMID:27329068

  11. Piezo Voltage Controlled Planar Hall Effect Devices.

    PubMed

    Zhang, Bao; Meng, Kang-Kang; Yang, Mei-Yin; Edmonds, K W; Zhang, Hao; Cai, Kai-Ming; Sheng, Yu; Zhang, Nan; Ji, Yang; Zhao, Jian-Hua; Zheng, Hou-Zhi; Wang, Kai-You

    2016-01-01

    The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the piezo voltage controlled Co2FeAl planar Hall effect devices without the external magnetic field. Our demonstration may lead to the realization of both information storage and processing using ferromagnetic materials. PMID:27329068

  12. PULSED ION SOURCE

    DOEpatents

    Ford, F.C.; Ruff, J.W.; Zizzo, S.G.; Cook, B.

    1958-11-11

    An ion source is described adapted for pulsed operation and producing copious quantities of ions with a particular ion egress geometry. The particular source construction comprises a conical member having a conducting surface formed of a metal with a gas occladed therein and narrow non-conducting portions hereon dividing the conducting surface. A high voltage pulse is applied across the conducting surface or producing a discharge across the surface. After the gas ions have been produced by the discharge, the ions are drawn from the source in a diverging conical beam by a specially constructed accelerating electrode.

  13. Electro-optical voltage sensor head

    DOEpatents

    Woods, G.K.

    1998-03-24

    A miniature electro-optic voltage sensor system capable of accurate operation at high voltages is disclosed. The system employs a transmitter, a sensor disposed adjacent to but out of direct electrical contact with a conductor on which the voltage is to be measured, a detector, and a signal processor. The transmitter produces a beam of electromagnetic radiation which is routed into the sensor where the beam undergoes the Pockels electro-optic effect. The electro-optic effect causes phase shifting in the beam, which is in turn converted to a pair of independent beams, from which the voltage of a system based on its E-field is determined when the two beams are normalized by the signal processor. The sensor converts the beam by splitting the beam in accordance with the axes of the beam`s polarization state (an ellipse whose ellipticity varies between -1 and +1 in proportion to voltage) into at least two AM signals. These AM signals are fed into a signal processor and processed to determine the voltage between a ground conductor and the conductor on which voltage is being measured. 6 figs.

  14. Electro-optical voltage sensor head

    DOEpatents

    Woods, Gregory K.

    1998-01-01

    A miniature electro-optic voltage sensor system capable of accurate operation at high voltages. The system employs a transmitter, a sensor disposed adjacent to but out of direct electrical contact with a conductor on which the voltage is to be measured, a detector, and a signal processor. The transmitter produces a beam of electromagnetic radiation which is routed into the sensor where the beam undergoes the Pockels electro-optic effect. The electro-optic effect causes phase shifting in the beam, which is in turn converted to a pair of independent beams, from which the voltage of a system based on its E-field is determined when the two beams are normalized by the signal processor. The sensor converts the beam by splitting the beam in accordance with the axes of the beam's polarization state (an ellipse whose ellipticity varies between -1 and +1 in proportion to voltage) into at least two AM signals. These AM signals are fed into a signal processor and processed to determine the voltage between a ground conductor and the conductor on which voltage is being measured.

  15. Enhanced Archaerhodopsin Fluorescent Protein Voltage Indicators

    PubMed Central

    Gong, Yiyang; Li, Jin Zhong; Schnitzer, Mark J.

    2013-01-01

    A longstanding goal in neuroscience has been to develop techniques for imaging the voltage dynamics of genetically defined subsets of neurons. Optical sensors of transmembrane voltage would enhance studies of neural activity in contexts ranging from individual neurons cultured in vitro to neuronal populations in awake-behaving animals. Recent progress has identified Archaerhodopsin (Arch) based sensors as a promising, genetically encoded class of fluorescent voltage indicators that can report single action potentials. Wild-type Arch exhibits sub-millisecond fluorescence responses to trans-membrane voltage, but its light-activated proton pump also responds to the imaging illumination. An Arch mutant (Arch-D95N) exhibits no photocurrent, but has a slower, ~40 ms response to voltage transients. Here we present Arch-derived voltage sensors with trafficking signals that enhance their localization to the neural membrane. We also describe Arch mutant sensors (Arch-EEN and -EEQ) that exhibit faster kinetics and greater fluorescence dynamic range than Arch-D95N, and no photocurrent at the illumination intensities normally used for imaging. We benchmarked these voltage sensors regarding their spike detection fidelity by using a signal detection theoretic framework that takes into account the experimentally measured photon shot noise and optical waveforms for single action potentials. This analysis revealed that by combining the sequence mutations and enhanced trafficking sequences, the new sensors improved the fidelity of spike detection by nearly three-fold in comparison to Arch-D95N. PMID:23840563

  16. Photoacoustic imaging of voltage signals (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Rao, Bin; Zhang, Ruiying; Wang, Lihong V.

    2016-03-01

    Optical imaging of brain voltage signals is significantly limited in depth due to optical scattering and the absorptive property of brain tissue. Photoacoustic (PA) imaging promises to break this hard limit by utilizing both ballistic and diffused photons. To demonstrate the feasibility of PA, we used an in vivo mouse model. The brain cortex tissue was stained with dipicrylamine dye, electrically stimulated, and imaged with a customized dual-isosbestic-wavelength PA microscope (DIW-PAM). DIW-PAM separates voltage-induced PA signals from blood-induced PA signals and thereby allows recording the voltage response of mouse cortex tissue without interference from hemoglobin responses. The resting state PA voltage response signal exhibited a noise-like signal in the frequency domain. Upon 3 Hz electrical stimulation, the PA voltage response signal showed frequency peaks of 3.2 Hz and 6.3 Hz (Fig. 1). Although dipicrylamine dye is not fast enough for recording neuron action potentials, it served well for the purpose of this feasibility study. In conclusion, we successfully demonstrated in vivo photoacoustic imaging of mouse brain voltage signals for the first time. If a fast voltage-sensitive dye is available, using photoacoustic computed tomography (PACT) instead of PA microscopy could allow acquiring full-field PA action potential images at a speed limited only by the laser pulse repetition rate.

  17. 30 CFR 75.826 - High-voltage trailing cables.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage trailing cables. 75.826 Section 75... HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution High-Voltage Longwalls § 75.826 High-voltage trailing cables. High-voltage trailing cables must: (a)...

  18. 30 CFR 75.826 - High-voltage trailing cables.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false High-voltage trailing cables. 75.826 Section 75... HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution High-Voltage Longwalls § 75.826 High-voltage trailing cables. High-voltage trailing cables must: (a)...

  19. 30 CFR 75.826 - High-voltage trailing cables.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false High-voltage trailing cables. 75.826 Section 75... HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution High-Voltage Longwalls § 75.826 High-voltage trailing cables. High-voltage trailing cables must: (a)...

  20. 30 CFR 75.826 - High-voltage trailing cables.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false High-voltage trailing cables. 75.826 Section 75... HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution High-Voltage Longwalls § 75.826 High-voltage trailing cables. High-voltage trailing cables must: (a)...

  1. Fuel Cell/Electrochemical Cell Voltage Monitor

    NASA Technical Reports Server (NTRS)

    Vasquez, Arturo

    2012-01-01

    A concept has been developed for a new fuel cell individual-cell-voltage monitor that can be directly connected to a multi-cell fuel cell stack for direct substack power provisioning. It can also provide voltage isolation for applications in high-voltage fuel cell stacks. The technology consists of basic modules, each with an 8- to 16-cell input electrical measurement connection port. For each basic module, a power input connection would be provided for direct connection to a sub-stack of fuel cells in series within the larger stack. This power connection would allow for module power to be available in the range of 9-15 volts DC. The relatively low voltage differences that the module would encounter from the input electrical measurement connection port, coupled with the fact that the module's operating power is supplied by the same substack voltage input (and so will be at similar voltage), provides for elimination of high-commonmode voltage issues within each module. Within each module, there would be options for analog-to-digital conversion and data transfer schemes. Each module would also include a data-output/communication port. Each of these ports would be required to be either non-electrical (e.g., optically isolated) or electrically isolated. This is necessary to account for the fact that the plurality of modules attached to the stack will normally be at a range of voltages approaching the full range of the fuel cell stack operating voltages. A communications/ data bus could interface with the several basic modules. Options have been identified for command inputs from the spacecraft vehicle controller, and for output-status/data feeds to the vehicle.

  2. High-voltage terminal test of a test stand for a 1-MV electrostatic accelerator

    NASA Astrophysics Data System (ADS)

    Park, Sae-Hoon; Kim, Yu-Seok

    2015-10-01

    The Korea Multipurpose Accelerator Complex has been developing a 300-kV test stand for a 1-MV electrostatic accelerator ion source. The ion source and accelerating tube will be installed in a high-pressure vessel. The ion source in the high-pressure vessel is required to have a high reliability. The test stand has been proposed and developed to confirm the stable operating conditions of the ion source. The ion source will be tested at the test stand to verify the long-time operating conditions. The test stand comprises a 300-kV high-voltage terminal, a battery for the ion-source power, a 60-Hz inverter, 200-MHz radio-frequency power supply, a 5-kV extraction power supply, a 300-kV accelerating tube, and a vacuum system. The results of the 300-kV high-voltage terminal tests are presented in this paper.

  3. Analysis of NSTX TF Joint Voltage Measurements

    SciTech Connect

    R, Woolley

    2005-10-07

    This report presents findings of analyses of recorded current and voltage data associated with 72 electrical joints operating at high current and high mechanical stress. The analysis goal was to characterize the mechanical behavior of each joint and thus evaluate its mechanical supports. The joints are part of the toroidal field (TF) magnet system of the National Spherical Torus Experiment (NSTX) pulsed plasma device operating at the Princeton Plasma Physics Laboratory (PPPL). Since there is not sufficient space near the joints for much traditional mechanical instrumentation, small voltage probes were installed on each joint and their voltage monitoring waveforms have been recorded on sampling digitizers during each NSTX ''shot''.

  4. Ultrasonic evaluation of high voltage circuit boards

    NASA Technical Reports Server (NTRS)

    Klima, S. J.; Riley, T. J.

    1976-01-01

    Preliminary observations indicate that an ultrasonic scanning technique may be useful as a quick, low cost, nondestructive method for judging the quality of circuit board materials for high voltage applications. Corona inception voltage tests were conducted on fiberglass-epoxy and fiberglass-polyimide high pressure laminates from 20 to 140 C. The same materials were scanned ultrasonically by utilizing the single transducer, through-transmission technique with reflector plate, and recording variations in ultrasonic energy transmitted through the board thickness. A direct relationship was observed between ultrasonic transmission level and corona inception voltage. The ultrasonic technique was subsequently used to aid selection of high quality circuit boards for the Communications Technology Satellite.

  5. 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

  6. Inductive voltage adder advanced hydrodynamic radiographic technology demonstration

    SciTech Connect

    Mazarakis, M.G.; Poukey, J.W.; Maenchen; Rovang, D.C.

    1997-04-01

    This paper presents the design, results, and analysis of a high-brightness electron beam technology demonstration experiment completed at Sandia National Laboratories, performed in collaboration with Los Alamos National Laboratory. The anticipated electron beam parameters were: 12 MeV, 35-40 kA, 0.5-mm rms radius, and 40-ns full width half maximum (FWHM) pulse duration. This beam, on an optimum thickness tantalum converter, should produce a very intense x-ray source of {approximately} 1.5-mm spot size and 1 kR dose @ 1 m. The accelerator utilized was SABRE, a pulsed inductive voltage adder, and the electron source was a magnetically immersed foilless electron diode. For these experiments, SABRE was modified to high-impedance negative-polarity operation. A new 100-ohm magnetically insulated transmission line cathode electrode was designed and constructed; the cavities were rotated 180{degrees} poloidally to invert the central electrode polarity to negative; and only one of the two pulse forming lines per cavity was energized. A twenty- to thirty-Tesla solenoidal magnet insulated the diode and contained the beam at its extremely small size. These experiments were designed to demonstrate high electron currents in submillimeter radius beams resulting in a high-brightness high-intensity flash x-ray source for high-resolution thick-object hydrodynamic radiography. The SABRE facility high-impedance performance was less than what was hoped. The modifications resulted in a lower amplitude (9 MV), narrower-than-anticipated triangular voltage pulse, which limited the dose to {approximately} 20% of the expected value. In addition, halo and ion-hose instabilities increased the electron beam spot size to > 1.5 mm. Subsequent, more detailed calculations explain these reduced output parameters. An accelerator designed (versus retrofit) for this purpose would provide the desired voltage and pulse shape.

  7. 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.

  8. 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.

  9. 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

  10. Thermally-induced voltage alteration for integrated circuit analysis

    DOEpatents

    Cole, Jr., Edward I.

    2000-01-01

    A thermally-induced voltage alteration (TIVA) apparatus and method are disclosed for analyzing an integrated circuit (IC) either from a device side of the IC or through the IC substrate to locate any open-circuit or short-circuit defects therein. The TIVA apparatus uses constant-current biasing of the IC while scanning a focused laser beam over electrical conductors (i.e. a patterned metallization) in the IC to produce localized heating of the conductors. This localized heating produces a thermoelectric potential due to the Seebeck effect in any conductors with open-circuit defects and a resistance change in any conductors with short-circuit defects, both of which alter the power demand by the IC and thereby change the voltage of a source or power supply providing the constant-current biasing. By measuring the change in the supply voltage and the position of the focused and scanned laser beam over time, any open-circuit or short-circuit defects in the IC can be located and imaged. The TIVA apparatus can be formed in part from a scanning optical microscope, and has applications for qualification testing or failure analysis of ICs.

  11. 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.

  12. Bipolar high-repetition-rate high-voltage nanosecond pulser

    SciTech Connect

    Tian Fuqiang; Wang Yi; Shi Hongsheng; Lei Qingquan

    2008-06-15

    The pulser designed is mainly used for producing corona plasma in waste water treatment system. Also its application in study of dielectric electrical properties will be discussed. The pulser consists of a variable dc power source for high-voltage supply, two graded capacitors for energy storage, and the rotating spark gap switch. The key part is the multielectrode rotating spark gap switch (MER-SGS), which can ensure wider range modulation of pulse repetition rate, longer pulse width, shorter pulse rise time, remarkable electrical field distortion, and greatly favors recovery of the gap insulation strength, insulation design, the life of the switch, etc. The voltage of the output pulses switched by the MER-SGS is in the order of 3-50 kV with pulse rise time of less than 10 ns and pulse repetition rate of 1-3 kHz. An energy of 1.25-125 J per pulse and an average power of up to 10-50 kW are attainable. The highest pulse repetition rate is determined by the driver motor revolution and the electrode number of MER-SGS. Even higher voltage and energy can be switched by adjusting the gas pressure or employing N{sub 2} as the insulation gas or enlarging the size of MER-SGS to guarantee enough insulation level.

  13. Source-circuit design overview

    NASA Technical Reports Server (NTRS)

    Ross, R. G., Jr.

    1983-01-01

    The source circuit is the fundamental electrical building block of a large central-station array; it consists of a series-parallel network of solar cells that develops full system voltage. The array field is generally made up of a large number of parallel source circuits. Source-circuit electrical configuration is driven by a number of design considerations, which must be considered simultaneously. Array fault tolerance and hot spot heating endurance are examined in detail.

  14. Concrete coatings: High-voltage spark testing and pinhole elimination

    SciTech Connect

    1999-10-01

    Polyurethane (PU) coatings are a popular means of protecting concrete surfaces. However, the interaction of the coating with the concrete can cause holiday detection to be difficult. Recently, the high-voltage spark method was used to test a PU coating on a concrete tank. Holidays were found and marked and the coating was repaired and retested. However, leaks appeared when the vessel was filled with water for hydrotesting, and a trough was drained to pinpoint the source of the leaks. The paper attempts to answer why the first tests not detect these pinholes.

  15. High-voltage-compatible, fully depleted CCDs

    SciTech Connect

    Holland, Stephen E.; Bebek, Chris J.; Dawson, Kyle S.; Emes, JohnE.; Fabricius, Max H.; Fairfield, Jessaym A.; Groom, Don E.; Karcher, A.; Kolbe, William F.; Palaio, Nick P.; Roe, Natalie A.; Wang, Guobin

    2006-05-15

    We describe charge-coupled device (CCD) developmentactivities at the Lawrence Berkeley National Laboratory (LBNL).Back-illuminated CCDs fabricated on 200-300 mu m thick, fully depleted,high-resistivity silicon substrates are produced in partnership with acommercial CCD foundry.The CCDs are fully depleted by the application ofa substrate bias voltage. Spatial resolution considerations requireoperation of thick, fully depleted CCDs at high substrate bias voltages.We have developed CCDs that are compatible with substrate bias voltagesof at least 200V. This improves spatial resolution for a given thickness,and allows for full depletion of thicker CCDs than previously considered.We have demonstrated full depletion of 650-675 mu m thick CCDs, withpotential applications in direct x-ray detection. In this work we discussthe issues related to high-voltage operation of fully depleted CCDs, aswell as experimental results on high-voltage-compatible CCDs.

  16. Pyrotechnic Simulator/Stray-Voltage Detector

    NASA Technical Reports Server (NTRS)

    Greenfield, Terry

    2009-01-01

    The concept for a dual test item has been developed for use in simulating live initiators/detonators during ground testing to verify the proper operation of the safing and firing circuitry for ground and flight systems ordnance as well as continuous monitoring for any stray voltages. Previous ordnance simulators have consisted of fuses, flash bulbs, inert devices with bridge wires, and actual live ordnance items mounted in test chambers. Stray voltage detectors have included devices connected to the firing circuits for continuous monitoring and a final no-voltage test just prior to ordnance connection. The purpose of this combined ordnance simulation and stray-voltage detection is to provide an improved and comprehensive method to ensure the ordnance circuitry is verified safe and operational.

  17. pH-Insensitive FRET voltage dyes.

    PubMed

    Maher, Michael P; Wu, Nyan-Tsz; Ao, Hong

    2007-08-01

    Many high-throughput ion channel assays require the use of voltage-sensitive dyes to detect channel activity in the presence of test compounds. Dye systems employing Förster resonance energy transfer (FRET) between 2 membrane-bound dyes are advantageous in combining high sensitivity, relatively fast response, and ratiometric output. The most widely used FRET voltage dye system employs a coumarin fluorescence donor whose excitation spectrum is pH dependent. The authors have validated a new class of voltage-sensitive FRET donors based on a pyrene moiety. These dyes are significantly brighter than CC2-DMPE and are not pH sensitive in the physiological range. With the new dye system, the authors demonstrate a new high-throughput assay for the acid-sensing ion channel (ASIC) family. They also introduce a novel method for absolute calibration of voltage-sensitive dyes, simultaneously determining the resting membrane potential of a cell. PMID:17517905

  18. 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)

  19. Boeing's High Voltage Solar Tile Test Results

    NASA Technical Reports Server (NTRS)

    Reed, Brian J.; Harden, David E.; Ferguson, Dale C.; Snyder, David B.

    2002-01-01

    Real concerns of spacecraft charging and experience with solar array augmented electrostatic discharge arcs on spacecraft have minimized the use of high voltages on large solar arrays despite numerous vehicle system mass and efficiency advantages. Boeing's solar tile (patent pending) allows high voltage to be generated at the array without the mass and efficiency losses of electronic conversion. Direct drive electric propulsion and higher power payloads (lower spacecraft weight) will benefit from this design. As future power demand grows, spacecraft designers must use higher voltage to minimize transmission loss and power cable mass for very large area arrays. This paper will describe the design and discuss the successful test of Boeing's 500-Volt Solar Tile in NASA Glenn's Tenney chamber in the Space Plasma Interaction Facility. The work was sponsored by NASA's Space Solar Power Exploratory Research and Technology (SERT) Program and will result in updated high voltage solar array design guidelines being published.

  20. 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.

  1. System for increasing corona inception voltage of insulating oils

    DOEpatents

    Rohwein, Gerald J.

    1998-01-01

    The Corona Inception Voltage of insulating oils is increased by repetitive cycles of prestressing the oil with a voltage greater than the corona inception voltage, and either simultaneously or serially removing byproducts of corona by evacuation and heating the oil.

  2. The use of the charge-induced voltage alteration technique to analyze precursors to dielectric breakdown

    SciTech Connect

    Barton, D.L.; Cole, E.I. Jr.

    1992-09-01

    Charge-Induced Voltage Alteration (CIVA) is a new scanning electron microscopy technique to rapidly localize open conductors on integrated circuits (ICs). CIVA uses a constant current source to power the IC under test and produces an image by monitoring the variation in voltage supplied to the IC as a function of electron beam position. This concept of observing supply voltage changes as in CIVA has been applied to Tunneling Current Microscopy (TCM). TCM has been used to localize oxide defects in biased, large area MOS capacitors before oxide breakdown by measuring the fluctuations in current with electron beam position. These changes are normally on the order of 10 nA. Conventional current amplifiers normally limit the applied voltage thereby reducing the operational range of the TCM technique unless special circuit modifications are employed. By using a constant current source and monitoring the voltage changes across the capacitor being analyzed, there are no voltage limitations. Signal magnitudes on the order of 5 mV have been recorded from capacitor defects using the CIVA setup. A detailed description of the CIVA acquisition system used for TCM and a comparison with conventional TCM are provided. Images of oxide defects before breakdown are presented to show that, while the two approaches are comparable wid each has its own strengths and weaknesses, the CIVA approach is a superior technique for precursor localization.

  3. The use of the charge-induced voltage alteration technique to analyze precursors to dielectric breakdown

    SciTech Connect

    Barton, D.L.; Cole, E.I. Jr.

    1992-01-01

    Charge-Induced Voltage Alteration (CIVA) is a new scanning electron microscopy technique to rapidly localize open conductors on integrated circuits (ICs). CIVA uses a constant current source to power the IC under test and produces an image by monitoring the variation in voltage supplied to the IC as a function of electron beam position. This concept of observing supply voltage changes as in CIVA has been applied to Tunneling Current Microscopy (TCM). TCM has been used to localize oxide defects in biased, large area MOS capacitors before oxide breakdown by measuring the fluctuations in current with electron beam position. These changes are normally on the order of 10 nA. Conventional current amplifiers normally limit the applied voltage thereby reducing the operational range of the TCM technique unless special circuit modifications are employed. By using a constant current source and monitoring the voltage changes across the capacitor being analyzed, there are no voltage limitations. Signal magnitudes on the order of 5 mV have been recorded from capacitor defects using the CIVA setup. A detailed description of the CIVA acquisition system used for TCM and a comparison with conventional TCM are provided. Images of oxide defects before breakdown are presented to show that, while the two approaches are comparable wid each has its own strengths and weaknesses, the CIVA approach is a superior technique for precursor localization.

  4. Spacecraft high-voltage power supply construction

    NASA Technical Reports Server (NTRS)

    Sutton, J. F.; Stern, J. E.

    1975-01-01

    The design techniques, circuit components, fabrication techniques, and past experience used in successful high-voltage power supplies for spacecraft flight systems are described. A discussion of the basic physics of electrical discharges in gases is included and a design rationale for the prevention of electrical discharges is provided. Also included are typical examples of proven spacecraft high-voltage power supplies with typical specifications for design, fabrication, and testing.

  5. Spark gap with low breakdown voltage jitter

    DOEpatents

    Rohwein, G.J.; Roose, L.D.

    1996-04-23

    Novel spark gap devices and electrodes are disclosed. The novel spark gap devices and electrodes are suitable for use in a variety of spark gap device applications. The shape of the electrodes gives rise to local field enhancements and reduces breakdown voltage jitter. Breakdown voltage jitter of approximately 5% has been measured in spark gaps according the invention. Novel electrode geometries and materials are disclosed. 13 figs.

  6. Spark gap with low breakdown voltage jitter

    DOEpatents

    Rohwein, Gerald J.; Roose, Lars D.

    1996-01-01

    Novel spark gap devices and electrodes are disclosed. The novel spark gap devices and electrodes are suitable for use in a variety of spark gap device applications. The shape of the electrodes gives rise to local field enhancements and reduces breakdown voltage jitter. Breakdown voltage jitter of approximately 5% has been measured in spark gaps according the invention. Novel electrode geometries and materials are disclosed.

  7. 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.

  8. Constant voltage electro-slag remelting control

    DOEpatents

    Schlienger, Max E.

    1996-01-01

    A system for controlling electrode gap in an electro-slag remelt furnace has a constant regulated voltage and an eletrode which is fed into the slag pool at a constant rate. The impedance of the circuit through the slag pool is directly proportional to the gap distance. Because of the constant voltage, the system current changes are inversely proportional to changes in gap. This negative feedback causes the gap to remain stable.

  9. Constant voltage electro-slag remelting control

    DOEpatents

    Schlienger, M.E.

    1996-10-22

    A system for controlling electrode gap in an electro-slag remelt furnace has a constant regulated voltage and an electrode which is fed into the slag pool at a constant rate. The impedance of the circuit through the slag pool is directly proportional to the gap distance. Because of the constant voltage, the system current changes are inversely proportional to changes in gap. This negative feedback causes the gap to remain stable. 1 fig.

  10. Joint voltages resulting from lightning currents.

    SciTech Connect

    Johnson, William Arthur; Warne, Larry Kevin; Merewether, Kimball O.; Chen, Kenneth C.

    2007-03-01

    Simple formulas are given for the interior voltages appearing across bolted joints from exterior lightning currents. External slot and bolt inductances as well as internal slot and bolt diffusion effects are included. Both linear and ferromagnetic wall materials are considered. A useful simplification of the slot current distribution into linear stripline and cylindrical parts (near the bolts) allows the nonlinear voltages to be estimated in closed form.

  11. Improving transition voltage spectroscopy of molecular junctions

    NASA Astrophysics Data System (ADS)

    Markussen, Troels; Chen, Jingzhe; Thygesen, Kristian S.

    2011-04-01

    Transition voltage spectroscopy (TVS) is a promising spectroscopic tool for molecular junctions. The principles in TVS is to find the minimum on a Fowler-Nordheim plot where ln(I/V2) is plotted against 1/V and relate the voltage at the minimum Vmin to the closest molecular level. Importantly, Vmin is approximately half the voltage required to see a peak in the dI/dV curve. Information about the molecular level position can thus be obtained at relatively low voltages. In this work we show that the molecular level position can be determined at even lower voltages, Vmin(α), by finding the minimum of ln(I/Vα) with α<2. On the basis of a simple Lorentzian transmission model we analyze theoretical ab initio as well as experimental I-V curves and show that the voltage required to determine the molecular levels can be reduced by ~30% as compared to conventional TVS. As for conventional TVS, the symmetry/asymmetry of the molecular junction needs to be taken into account in order to gain quantitative information. We show that the degree of asymmetry may be estimated from a plot of Vmin(α) vs α.

  12. 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.

  13. 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

  14. The world's first high voltage GaN-on-Diamond power semiconductor devices

    NASA Astrophysics Data System (ADS)

    Baltynov, Turar; Unni, Vineet; Narayanan, E. M. Sankara

    2016-11-01

    This paper presents the detailed fabrication method and extensive electrical characterisation results of the first-ever demonstrated high voltage GaN power semiconductor devices on CVD Diamond substrate. Fabricated circular GaN-on-Diamond HEMTs with gate-to-drain drift length of 17 μm and source field plate length of 3 μm show an off-state breakdown voltage of ∼1100 V. Temperature characterisation of capacitance-voltage characteristics and on-state characteristics provides insight on the temperature dependence of key parameters such as threshold voltage, 2DEG sheet carrier concentration, specific on-state resistance, and drain saturation current in the fabricated devices.

  15. Continuous-flow multi-pulse electroporation at low DC voltages by microfluidic flipping of the voltage space topology

    NASA Astrophysics Data System (ADS)

    Bhattacharjee, N.; Horowitz, L. F.; Folch, A.

    2016-10-01

    Concerns over biosafety, cost, and carrying capacity of viral vectors have accelerated research into physical techniques for gene delivery such as electroporation and mechanoporation. Advances in microfabrication have made it possible to create high electric fields over microscales, resulting in more efficient DNA delivery and higher cell viability. Continuous-flow microfluidic methods are typically more suitable for cellular therapies where a large number of cells need to be transfected under sterile conditions. However, the existing continuous-flow designs used to generate multiple pulses either require expensive peripherals such as high-voltage (>400 V) sources or function generators, or result in reduced cell viability due to the proximity of the cells to the electrodes. In this paper, we report a continuous-flow microfluidic device whose channel geometry reduces instrumentation demands and minimizes cellular toxicity. Our design can generate multiple pulses of high DC electric field strength using significantly lower voltages (15-60 V) than previous designs. The cells flow along a serpentine channel that repeatedly flips the cells between a cathode and an anode at high throughput. The cells must flow through a constriction each time they pass from an anode to a cathode, exposing them to high electric field strength for short durations of time (the "pulse-width"). A conductive biocompatible poly-aniline hydrogel network formed in situ is used to apply the DC voltage without bringing the metal electrodes close to the cells, further sheltering cells from the already low voltage electrodes. The device was used to electroporate multiple cell lines using electric field strengths between 700 and 800 V/cm with transfection efficiencies superior than previous flow-through designs.

  16. A dynamic infrared source

    NASA Astrophysics Data System (ADS)

    Persky, M. J.

    2003-12-01

    A system is described that can be used for testing infrared focal plane cameras in situations where conventional blackbody sources are deficient. The system uses readily available components, electronics, and software. It can provide either a wide area or a point source of infrared flux that can be programmed to follow a prescribed temporal profile at higher rates than available from commercial blackbody sources and with excellent repeatability. Additionally, the system provides flux without suffering from the temporal noise characteristic of commercial, wide area, flat sheet sources that results from turbulence in front of the blackbody. The system consists of commercially available, rapid rise time infrared radiators, either coupled to an integrating sphere for broad area flux, or used individually with a pinhole and collimator as a point source. A programmable voltage supply provides the power versus time profile at frequencies to several Hertz. Transfer from a standard blackbody calibrates the flux levels. This article provides a description, testing results, and application examples.

  17. Piezotube borehole seismic source

    DOEpatents

    Daley, Tom M; Solbau, Ray D; Majer, Ernest L

    2014-05-06

    A piezoelectric borehole source capable of permanent or semipermanent insertion into a well for uninterrupted well operations is described. The source itself comprises a series of piezoelectric rings mounted to an insulative mandrel internally sized to fit over a section of well tubing, the rings encased in a protective housing and electrically connected to a power source. Providing an AC voltage to the rings will cause expansion and contraction sufficient to create a sonic pulse. The piezoelectric borehole source fits into a standard well, and allows for uninterrupted pass-through of production tubing, and other tubing and electrical cables. Testing using the source may be done at any time, even concurrent with well operations, during standard production.

  18. Radiation source

    DOEpatents

    Thode, Lester E.

    1981-01-01

    A device and method for relativistic electron beam heating of a high-density plasma in a small localized region. A relativistic electron beam generator or accelerator produces a high-voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low-density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high-density target plasma which typically comprises DT, DD, or similar thermonuclear gas at a density of 10.sup.17 to 10.sup.20 electrons per cubic centimeter. The target gas is ionized prior to application of the relativistic electron beam by means of a laser or other preionization source to form a plasma. Utilizing a relativistic electron beam with an individual particle energy exceeding 3 MeV, classical scattering by relativistic electrons passing through isolation foils is negligible. As a result, relativistic streaming instabilities are initiated within the high-density target plasma causing the relativistic electron beam to efficiently deposit its energy into a small localized region of the high-density plasma target.

  19. Experimental verification of HVDC test sources requirements for pollution tests

    SciTech Connect

    Chagas, F.A.; Kuffel, E.

    1995-04-01

    This paper presents the results of tests conducted to verify the effect of the voltage source on the critical flashover voltage of dc insulators under pollution. Tests were performed under 3 pollution levels using voltage sources with different voltage drop x leakage current characteristics. A data acquisition system was used to record all current pulses above a certain pre selected current pulse duration, which made possible a complete analysis of current pulses and voltage drops characteristics. The experimental results show that the present restrictions imposed on the dc voltage sources can probably be relaxed. Also from the experimental data collected it was found that the insulator tested presents a constant impedance x current characteristic. This characteristic can be useful in checking theoretical models for polluted insulator flashover.

  20. OLED area illumination source

    DOEpatents

    Foust, Donald Franklin; Duggal, Anil Raj; Shiang, Joseph John; Nealon, William Francis; Bortscheller, Jacob Charles

    2008-03-25

    The present invention relates to an area illumination light source comprising a plurality of individual OLED panels. The individual OLED panels are configured in a physically modular fashion. Each OLED panel comprising a plurality of OLED devices. Each OLED panel comprises a first electrode and a second electrode such that the power being supplied to each individual OLED panel may be varied independently. A power supply unit capable of delivering varying levels of voltage simultaneously to the first and second electrodes of each of the individual OLED panels is also provided. The area illumination light source also comprises a mount within which the OLED panels are arrayed.

  1. Multilevel-Dc-Bus Inverter For Providing Sinusoidal And Pwm Electrical Machine Voltages

    DOEpatents

    Su, Gui-Jia [Knoxville, TN

    2005-11-29

    A circuit for controlling an ac machine comprises a full bridge network of commutation switches which are connected to supply current for a corresponding voltage phase to the stator windings, a plurality of diodes, each in parallel connection to a respective one of the commutation switches, a plurality of dc source connections providing a multi-level dc bus for the full bridge network of commutation switches to produce sinusoidal voltages or PWM signals, and a controller connected for control of said dc source connections and said full bridge network of commutation switches to output substantially sinusoidal voltages to the stator windings. With the invention, the number of semiconductor switches is reduced to m+3 for a multi-level dc bus having m levels. A method of machine control is also disclosed.

  2. High voltage testing for the Majorana Demonstrator

    DOE PAGES

    Abgrall, N.; Arnquist, I. J.; Avignone, III, F. T.; Barabash, A. S.; Bertrand, F. E.; Bradley, A. W.; Brudanin, V.; Busch, M.; Buuck, M.; Byram, D.; et al

    2016-04-04

    The Majorana Collaboration is constructing the Majorana Demonstrator, an ultra-low background, 44-kg modular high-purity Ge (HPGe) detector array to search for neutrinoless double-beta decay in 76Ge. The phenomenon of surface micro-discharge induced by high-voltage has been studied in the context of the Majorana Demonstrator. This effect can damage the front-end electronics or mimic detector signals. To ensure the correct performance, every high-voltage cable and feedthrough must be capable of supplying HPGe detector operating voltages as high as 5 kV without exhibiting discharge. R&D measurements were carried out to understand the testing system and determine the optimum design configuration of themore » high-voltage path, including different improvements of the cable layout and feedthrough flange model selection. Every cable and feedthrough to be used at the Majorana Demonstrator was characterized and the micro-discharge effects during the Majorana Demonstrator commissioning phase were studied. Furthermore, a stable configuration has been achieved, and the cables and connectors can supply HPGe detector operating voltages without exhibiting discharge.« less

  3. High voltage testing for the MAJORANA DEMONSTRATOR

    NASA Astrophysics Data System (ADS)

    Abgrall, N.; Arnquist, I. J.; Avignone, F. T.; Barabash, A. S.; Bertrand, F. E.; Bradley, A. W.; Brudanin, V.; Busch, M.; Buuck, M.; Byram, D.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Chu, P.-H.; Cuesta, C.; Detwiler, J. A.; Doe, P. J.; Dunagan, C.; Efremenko, Yu.; Ejiri, H.; Elliott, S. R.; Fu, Z.; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guinn, I. S.; Guiseppe, V. E.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Jasinski, B. R.; Keeter, K. J.; Kidd, M. F.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; Li, A.; MacMullin, J.; Martin, R. D.; Massarczyk, R.; Meijer, S. J.; Mertens, S.; Orrell, J. L.; O'Shaughnessy, C.; Poon, A. W. P.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G. H.; Romero-Romero, E.; Shanks, B.; Shirchenko, M.; Snyder, N.; Suriano, A. M.; Tedeschi, D.; Thompson, A.; Ton, K. T.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Yu, C.-H.; Yumatov, V.

    2016-07-01

    The MAJORANA Collaboration is constructing the MAJORANA DEMONSTRATOR, an ultra-low background, 44-kg modular high-purity Ge (HPGe) detector array to search for neutrinoless double-beta decay in 76Ge. The phenomenon of surface micro-discharge induced by high-voltage has been studied in the context of the MAJORANA DEMONSTRATOR. This effect can damage the front-end electronics or mimic detector signals. To ensure the correct performance, every high-voltage cable and feedthrough must be capable of supplying HPGe detector operating voltages as high as 5 kV without exhibiting discharge. R&D measurements were carried out to understand the testing system and determine the optimum design configuration of the high-voltage path, including different improvements of the cable layout and feedthrough flange model selection. Every cable and feedthrough to be used at the MAJORANA DEMONSTRATOR was characterized and the micro-discharge effects during the MAJORANA DEMONSTRATOR commissioning phase were studied. A stable configuration has been achieved, and the cables and connectors can supply HPGe detector operating voltages without exhibiting discharge.

  4. Maximum permissible voltage of YBCO coated conductors

    NASA Astrophysics Data System (ADS)

    Wen, J.; Lin, B.; Sheng, J.; Xu, J.; Jin, Z.; Hong, Z.; Wang, D.; Zhou, H.; Shen, X.; Shen, C.

    2014-06-01

    Superconducting fault current limiter (SFCL) could reduce short circuit currents in electrical power system. One of the most important thing in developing SFCL is to find out the maximum permissible voltage of each limiting element. The maximum permissible voltage is defined as the maximum voltage per unit length at which the YBCO coated conductors (CC) do not suffer from critical current (Ic) degradation or burnout. In this research, the time of quenching process is changed and voltage is raised until the Ic degradation or burnout happens. YBCO coated conductors test in the experiment are from American superconductor (AMSC) and Shanghai Jiao Tong University (SJTU). Along with the quenching duration increasing, the maximum permissible voltage of CC decreases. When quenching duration is 100 ms, the maximum permissible of SJTU CC, 12 mm AMSC CC and 4 mm AMSC CC are 0.72 V/cm, 0.52 V/cm and 1.2 V/cm respectively. Based on the results of samples, the whole length of CCs used in the design of a SFCL can be determined.

  5. Failure Modes during Low-Voltage Electrowetting.

    PubMed

    Mibus, Marcel; Hu, Xiaoyu; Knospe, Carl; Reed, Michael L; Zangari, Giovanni

    2016-06-22

    Low-voltage electrowetting devices allow significant contact angle changes below a 50 V bias; however, operation under prolonged cycling and failure modes have not yet been sufficiently elucidated. In this work, the failure modes and performance degradation of Cytop (23-210 nm)/aluminum oxide (15-44 nm) bilayers have been investigated. Contact angle and leakage current were measured during stepped voltage measurements up to failure, showing three electrowetting response regimes: ideal Young-Lippmann behavior, contact angle saturation, and dielectric breakdown. The onset of ionic conduction in aluminum oxide and the resulting breakdown control when the layer would ultimately fail, but the thickness of the Cytop layer determined the achievable contact angle versus voltage characteristics. Cyclic electrowetting measurements studied the repeatability of contact angle change using an applied voltage above or below the voltage drop needed for polymer breakdown (VT). Results show repeatable electrowetting below VT and a rapidly diminishing contact angle response above VT. The leakage current and injected charge cannot be used to comprehensively assess the stability of the system during operation. The contact potential difference measured with a Kelvin probe provides an alternative means of assessing the extent of the damage. PMID:27253515

  6. Two-Photon Lifetime Imaging of Voltage Indicating Proteins as a Probe of Absolute Membrane Voltage.

    PubMed

    Brinks, Daan; Klein, Aaron J; Cohen, Adam E

    2015-09-01

    Genetically encoded voltage indicators (GEVIs) can report cellular electrophysiology with high resolution in space and time. Two-photon (2P) fluorescence has been explored as a means to image voltage in tissue. Here, we used the 2P electronic excited-state lifetime to probe absolute membrane voltage in a manner that is insensitive to the protein expression level, illumination intensity, or photon detection efficiency. First, we tested several GEVIs for 2P brightness, response speed, and voltage sensitivity. ASAP1 and a previously described citrine-Arch electrochromic Förster resonance energy transfer sensor (dubbed CAESR) showed the best characteristics. We then characterized the voltage-dependent lifetime of ASAP1, CAESR, and ArcLight under voltage-clamp conditions. ASAP1 and CAESR showed voltage-dependent lifetimes, whereas ArcLight did not. These results establish 2P fluorescence lifetime imaging as a viable means of measuring absolute membrane voltage. We discuss the prospects and improvements necessary for applications in tissue.

  7. Two-Photon Lifetime Imaging of Voltage Indicating Proteins as a Probe of Absolute Membrane Voltage.

    PubMed

    Brinks, Daan; Klein, Aaron J; Cohen, Adam E

    2015-09-01

    Genetically encoded voltage indicators (GEVIs) can report cellular electrophysiology with high resolution in space and time. Two-photon (2P) fluorescence has been explored as a means to image voltage in tissue. Here, we used the 2P electronic excited-state lifetime to probe absolute membrane voltage in a manner that is insensitive to the protein expression level, illumination intensity, or photon detection efficiency. First, we tested several GEVIs for 2P brightness, response speed, and voltage sensitivity. ASAP1 and a previously described citrine-Arch electrochromic Förster resonance energy transfer sensor (dubbed CAESR) showed the best characteristics. We then characterized the voltage-dependent lifetime of ASAP1, CAESR, and ArcLight under voltage-clamp conditions. ASAP1 and CAESR showed voltage-dependent lifetimes, whereas ArcLight did not. These results establish 2P fluorescence lifetime imaging as a viable means of measuring absolute membrane voltage. We discuss the prospects and improvements necessary for applications in tissue. PMID:26331249

  8. A Comparison of High-Voltage Switches

    SciTech Connect

    Chu, K.W.; Scott, G.L.

    1999-02-01

    This report summarizes our work on high-voltage switches during the past few years. With joint funding from the Department of Energy (DOE) and the Department of Defense (DOD), we tested a wide variety of switches to a common standard. This approach permitted meaningful comparisons between disparate switches. Most switches were purchased from commercial sources, though some were experimental devices. For the purposes of this report, we divided the switches into three generic types (gas, vacuum, and semiconductor) and selected data that best illustrates important strengths and weaknesses of each switch type. Test techniques that indicate the state of health of the switches are emphasized. For example, a good indicator of residual gas in a vacuum switch is the systematic variation of the switching delay in response to changes in temperature and/or operating conditions. We believe that the presentation of this kind of information will help engineers to select and to test switches for their particular applications. Our work was limited to switches capable of driving slappers. Also known as exploding-foil initiators, slappers are detonators that initiate a secondary explosive by direct impact with a small piece of matter moving at the detonation velocity (several thousands of meters per second). A slapper is desirable for enhanced safety (no primary explosive), but it also places extra demands on the capacitor-discharge circuit to deliver a fast-rising current pulse (greater than 10 A/ns) of several thousand amperes. The required energy is substantially less than one joule; but this energy is delivered in less than one microsecond, taking the peak power into the megawatt regime. In our study, the switches operated in the 1 kV to 3 kV range and were physically small, roughly 1 cm{sup 3} or less. Although a fuze functions only once in actual use, multiple-shot capability is important for production testing and for research work. For this reason, we restricted this report

  9. Voltage control of cavity magnon polariton

    NASA Astrophysics Data System (ADS)

    Kaur, S.; Yao, B. M.; Rao, J. W.; Gui, Y. S.; Hu, C.-M.

    2016-07-01

    We have experimentally investigated the microwave transmission of the cavity-magnon-polariton (CMP) generated by integrating a low damping magnetic insulator onto a 2D microwave cavity. The high tunability of our planar cavity allows the cavity resonance frequency to be precisely controlled using a DC voltage. By appropriately tuning the voltage and magnetic bias, we can observe the cavity photon magnon coupling and the magnetic coupling between a magnetostatic mode and the generated CMP. The dispersion of the generated CMP was measured by either tuning the magnetic field or the applied voltage. This electrical control of CMP may open up avenues for designing advanced on-chip microwave devices that utilize light-matter interaction.

  10. Compact high voltage solid state switch

    DOEpatents

    Glidden, Steven C.

    2003-09-23

    A compact, solid state, high voltage switch capable of high conduction current with a high rate of current risetime (high di/dt) that can be used to replace thyratrons in existing and new applications. The switch has multiple thyristors packaged in a single enclosure. Each thyristor has its own gate drive circuit that circuit obtains its energy from the energy that is being switched in the main circuit. The gate drives are triggered with a low voltage, low current pulse isolated by a small inexpensive transformer. The gate circuits can also be triggered with an optical signal, eliminating the trigger transformer altogether. This approach makes it easier to connect many thyristors in series to obtain the hold off voltages of greater than 80 kV.

  11. Adhesive curing through low-voltage activation

    NASA Astrophysics Data System (ADS)

    Ping, Jianfeng; Gao, Feng; Chen, Jian Lin; Webster, Richard D.; Steele, Terry W. J.

    2015-08-01

    Instant curing adhesives typically fall within three categories, being activated by either light (photocuring), heat (thermocuring) or chemical means. These curing strategies limit applications to specific substrates and can only be activated under certain conditions. Here we present the development of an instant curing adhesive through low-voltage activation. The electrocuring adhesive is synthesized by grafting carbene precursors on polyamidoamine dendrimers and dissolving in aqueous solvents to form viscous gels. The electrocuring adhesives are activated at -2 V versus Ag/AgCl, allowing tunable crosslinking within the dendrimer matrix and on both electrode surfaces. As the applied voltage discontinued, crosslinking immediately terminated. Thus, crosslinking initiation and propagation are observed to be voltage and time dependent, enabling tuning of both material properties and adhesive strength. The electrocuring adhesive has immediate implications in manufacturing and development of implantable bioadhesives.

  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. Adhesive curing through low-voltage activation

    PubMed Central

    Ping, Jianfeng; Gao, Feng; Chen, Jian Lin; Webster, Richard D.; Steele, Terry W. J.

    2015-01-01

    Instant curing adhesives typically fall within three categories, being activated by either light (photocuring), heat (thermocuring) or chemical means. These curing strategies limit applications to specific substrates and can only be activated under certain conditions. Here we present the development of an instant curing adhesive through low-voltage activation. The electrocuring adhesive is synthesized by grafting carbene precursors on polyamidoamine dendrimers and dissolving in aqueous solvents to form viscous gels. The electrocuring adhesives are activated at −2 V versus Ag/AgCl, allowing tunable crosslinking within the dendrimer matrix and on both electrode surfaces. As the applied voltage discontinued, crosslinking immediately terminated. Thus, crosslinking initiation and propagation are observed to be voltage and time dependent, enabling tuning of both material properties and adhesive strength. The electrocuring adhesive has immediate implications in manufacturing and development of implantable bioadhesives. PMID:26282730

  14. High-voltage electrocution causing bulbar dysfunction.

    PubMed

    Parvathy, G; Shaji, C V; Kabeer, K A; Prasanth, S R

    2016-01-01

    Electrical shock can result in neurological complications, involving both peripheral and central nervous systems, which may present immediately or later on. High-voltage electrical injuries are uncommonly reported and may predispose to both immediate and delayed neurologic complications. We report the case of a 68-year-old man who experienced a high-voltage electrocution injury, subsequently developed bulbar dysfunction and spontaneously recovered. We describe the development of bulbar palsy following a significant electrical injury, which showed no evidence of this on magnetic resonance imaging. High-voltage electrocution injuries are a serious problem with potential for both immediate and delayed neurologic sequelae. The existing literature has no reports on bulbar dysfunction following electrocution, apart from motor neuron disease.

  15. Tuning decoherence with a voltage probe.

    PubMed

    Roulleau, P; Portier, F; Roche, P; Cavanna, A; Faini, G; Gennser, U; Mailly, D

    2009-06-12

    We present an experiment where we tune the decoherence in a quantum interferometer using one of the simplest objects available in the physics of quantum conductors: an Ohmic contact. For that purpose, we designed an electronic Mach-Zehnder interferometer which has one of its two arms connected to an Ohmic contact through a quantum point contact. At low temperature, we observe quantum interference patterns with a visibility up to 57%. Increasing the connection between one arm of the interferometer to the floating Ohmic contact, the voltage probe, reduces quantum interference as it probes the electron trajectory. This unique experimental realization of a voltage probe works as a trivial which-path detector whose efficiency can be simply tuned by a gate voltage.

  16. 30 CFR 75.813 - High-voltage longwalls; scope.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage longwalls; scope. 75.813 Section... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution High-Voltage Longwalls § 75.813 High-voltage longwalls; scope. Sections 75.814 through 75.822 of...

  17. 30 CFR 75.804 - Underground high-voltage cables.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Underground high-voltage cables. 75.804 Section... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution § 75.804 Underground high-voltage cables. (a) Underground high-voltage cables used in...

  18. 30 CFR 77.810 - High-voltage equipment; grounding.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false High-voltage equipment; grounding. 77.810... COAL MINES Surface High-Voltage Distribution § 77.810 High-voltage equipment; grounding. Frames, supporting structures, and enclosures of stationary, portable, or mobile high-voltage equipment shall...

  19. 30 CFR 77.810 - High-voltage equipment; grounding.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false High-voltage equipment; grounding. 77.810... COAL MINES Surface High-Voltage Distribution § 77.810 High-voltage equipment; grounding. Frames, supporting structures, and enclosures of stationary, portable, or mobile high-voltage equipment shall...

  20. 30 CFR 75.813 - High-voltage longwalls; scope.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false High-voltage longwalls; scope. 75.813 Section... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution High-Voltage Longwalls § 75.813 High-voltage longwalls; scope. Sections 75.814 through 75.822 of...

  1. 30 CFR 75.804 - Underground high-voltage cables.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Underground high-voltage cables. 75.804 Section... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution § 75.804 Underground high-voltage cables. (a) Underground high-voltage cables used in...

  2. 30 CFR 75.804 - Underground high-voltage cables.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Underground high-voltage cables. 75.804 Section... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution § 75.804 Underground high-voltage cables. (a) Underground high-voltage cables used in...

  3. 30 CFR 77.810 - High-voltage equipment; grounding.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false High-voltage equipment; grounding. 77.810... COAL MINES Surface High-Voltage Distribution § 77.810 High-voltage equipment; grounding. Frames, supporting structures, and enclosures of stationary, portable, or mobile high-voltage equipment shall...

  4. 30 CFR 75.813 - High-voltage longwalls; scope.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false High-voltage longwalls; scope. 75.813 Section... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution High-Voltage Longwalls § 75.813 High-voltage longwalls; scope. Sections 75.814 through 75.822 of...

  5. 30 CFR 75.813 - High-voltage longwalls; scope.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false High-voltage longwalls; scope. 75.813 Section... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution High-Voltage Longwalls § 75.813 High-voltage longwalls; scope. Sections 75.814 through 75.822 of...

  6. 30 CFR 75.804 - Underground high-voltage cables.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Underground high-voltage cables. 75.804 Section... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution § 75.804 Underground high-voltage cables. (a) Underground high-voltage cables used in...

  7. Electronic circuit for measuring series connected electrochemical cell voltages

    DOEpatents

    Ashtiani, Cyrus N.; Stuart, Thomas A.

    2000-01-01

    An electronic circuit for measuring voltage signals in an energy storage device is disclosed. The electronic circuit includes a plurality of energy storage cells forming the energy storage device. A voltage divider circuit is connected to at least one of the energy storage cells. A current regulating circuit is provided for regulating the current through the voltage divider circuit. A voltage measurement node is associated with the voltage divider circuit for producing a voltage signal which is proportional to the voltage across the energy storage cell.

  8. Gain results for low voltage FEL

    SciTech Connect

    Shaw, A.; Stuart, R.A.; Al-Shamma`a, A.

    1995-12-31

    We have designed and constructed a low voltage (130 kV) FEL system capable of operating in the microwave frequency range for which the electron beam current is cw (rather than pulsed) in time at a level of {approximately} 12 mA. The gain of this system has been measured as a function of the electron beam accelerating voltage and current level, and the input microwave frequency (8-10 GHz). The results are compared with the predictions of a simple theoretical model.

  9. Low-voltage differentially-signaled modulators.

    PubMed

    Zortman, William A; Lentine, Anthony L; Trotter, Douglas C; Watts, Michael R

    2011-12-19

    For exascale computing applications, viable optical solutions will need to operate using low voltage signaling and with low power consumption. In this work, the first differentially signaled silicon resonator is demonstrated which can provide a 5dB extinction ratio using 3fJ/bit and 500mV signal amplitude at 10Gbps. Modulation with asymmetric voltage amplitudes as low as 150mV with 3dB extinction are demonstrated at 10Gbps as well. Differentially signaled resonators simplify and expand the design space for modulator implementation and require no special drivers.

  10. Voltage Quench Dynamics of a Kondo System.

    PubMed

    Antipov, Andrey E; Dong, Qiaoyuan; Gull, Emanuel

    2016-01-22

    We examine the dynamics of a correlated quantum dot in the mixed valence regime. We perform numerically exact calculations of the current after a quantum quench from equilibrium by rapidly applying a bias voltage in a wide range of initial temperatures. The current exhibits short equilibration times and saturates upon the decrease of temperature at all times, indicating Kondo behavior both in the transient regime and in the steady state. The time-dependent current saturation temperature connects the equilibrium Kondo temperature to a substantially increased value at voltages outside of the linear response. These signatures are directly observable by experiments in the time domain. PMID:26849606

  11. Electrochemical microstructuring with short voltage pulses.

    PubMed

    Schuster, Rolf

    2007-01-01

    The application of short (nanosecond) voltage pulses between a tool electrode and a work piece immersed in an electrolyte solution allows the three-dimensional machining of electrochemically active materials with submicrometer resolution. The method is based on the finite charging time constant of the double-layer capacitance, which varies approximately linearly with the local separation between the electrode surfaces. Hence, the polarization of the electrodes during short pulses and subsequent electrochemical reactions are confined to regions where the electrodes are in sufficiently close proximity. This Minireview describes the principles behind electrochemical micro-structuring with short voltage pulses, and its current achievements and limitations. PMID:17111455

  12. An optimal control strategy for DC bus voltage regulation in photovoltaic system with battery energy storage.

    PubMed

    Daud, Muhamad Zalani; Mohamed, Azah; Hannan, M A

    2014-01-01

    This paper presents an evaluation of an optimal DC bus voltage regulation strategy for grid-connected photovoltaic (PV) system with battery energy storage (BES). The BES is connected to the PV system DC bus using a DC/DC buck-boost converter. The converter facilitates the BES power charge/discharge to compensate for the DC bus voltage deviation during severe disturbance conditions. In this way, the regulation of DC bus voltage of the PV/BES system can be enhanced as compared to the conventional regulation that is solely based on the voltage-sourced converter (VSC). For the grid side VSC (G-VSC), two control methods, namely, the voltage-mode and current-mode controls, are applied. For control parameter optimization, the simplex optimization technique is applied for the G-VSC voltage- and current-mode controls, including the BES DC/DC buck-boost converter controllers. A new set of optimized parameters are obtained for each of the power converters for comparison purposes. The PSCAD/EMTDC-based simulation case studies are presented to evaluate the performance of the proposed optimized control scheme in comparison to the conventional methods.

  13. An Optimal Control Strategy for DC Bus Voltage Regulation in Photovoltaic System with Battery Energy Storage

    PubMed Central

    Daud, Muhamad Zalani; Mohamed, Azah; Hannan, M. A.

    2014-01-01

    This paper presents an evaluation of an optimal DC bus voltage regulation strategy for grid-connected photovoltaic (PV) system with battery energy storage (BES). The BES is connected to the PV system DC bus using a DC/DC buck-boost converter. The converter facilitates the BES power charge/discharge to compensate for the DC bus voltage deviation during severe disturbance conditions. In this way, the regulation of DC bus voltage of the PV/BES system can be enhanced as compared to the conventional regulation that is solely based on the voltage-sourced converter (VSC). For the grid side VSC (G-VSC), two control methods, namely, the voltage-mode and current-mode controls, are applied. For control parameter optimization, the simplex optimization technique is applied for the G-VSC voltage- and current-mode controls, including the BES DC/DC buck-boost converter controllers. A new set of optimized parameters are obtained for each of the power converters for comparison purposes. The PSCAD/EMTDC-based simulation case studies are presented to evaluate the performance of the proposed optimized control scheme in comparison to the conventional methods. PMID:24883374

  14. Vacuum test bench for high-voltage tests of storage chambers in the electric dipole moment spectrometer

    NASA Astrophysics Data System (ADS)

    Lasakov, M. S.; Polyushkin, A. O.; Serebrov, A. P.; Kolomenskii, E. A.; Pirozhkov, A. N.; Krasnoshchekova, I. A.

    2016-04-01

    We describe the structure of the high-voltage test bench for checking individual insulators and their assemblies with separate control of leakage currents in each insulator. The test bench is mainly intended for preparing the high-voltage block of the spectrometer for the search for the electric dipole moment (EDM) of the neutron. The main part of the bench is the high-voltage source with controllable polarity and voltages up to 200 kV with complex control over parameters. An analogous converter is used in experiment on measuring the EDM of the neutron. We report on the results of testing the new design of the storage chambers of the EDM spectrometer operating with a high voltage; we also test the maximal potentialities of the converter under nearly working conditions; its optimization and calibration are performed.

  15. 250 kV 6 mA compact Cockcroft-Walton high-voltage power supply.

    PubMed

    Ma, Zhan-Wen; Su, Xiao-Dong; Lu, Xiao-Long; Wei, Zhen; Wang, Jun-Run; Huang, Zhi-Wu; Miao, Tian-You; Su, Tong-Ling; Yao, Ze-En

    2016-08-01

    A compact power supply system for a compact neutron generator has been developed. A 4-stage symmetrical Cockcroft-Walton circuit is adopted to produce 250 kV direct current high-voltage. A 2-stage 280 kV isolation transformer system is used to drive the ion source power supply. For a compact structure, safety, and reliability during the operation, the Cockcroft-Walton circuit and the isolation transformer system are enclosed in an epoxy vessel containing the transformer oil whose size is about ∅350 mm × 766 mm. Test results indicate that the maximum output voltage of the power supply is 282 kV, and the stability of the output voltage is better than 0.63% when the high voltage power supply is operated at 250 kV, 6.9 mA with the input voltage varying ±10%. PMID:27587170

  16. Investigation of channel width-dependent threshold voltage variation in a-InGaZnO thin-film transistors

    SciTech Connect

    Liu, Kuan-Hsien; Chou, Wu-Ching; Chang, Ting-Chang; Wu, Ming-Siou; Hung, Yi-Syuan; Sze, Simon M.; Hung, Pei-Hua; Chu, Ann-Kuo; Hsieh, Tien-Yu; Yeh, Bo-Liang

    2014-03-31

    This Letter investigates abnormal channel width-dependent threshold voltage variation in amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors. Unlike drain-induced source barrier lowering effect, threshold voltage increases with increasing drain voltage. Furthermore, the wider the channel, the larger the threshold voltage observed. Because of the surrounding oxide and other thermal insulating material and the low thermal conductivity of the IGZO layer, the self-heating effect will be pronounced in wider channel devices and those with a larger operating drain bias. To further clarify the physical mechanism, fast IV measurement is utilized to demonstrate the self-heating induced anomalous channel width-dependent threshold voltage variation.

  17. Investigation of channel width-dependent threshold voltage variation in a-InGaZnO thin-film transistors

    NASA Astrophysics Data System (ADS)

    Liu, Kuan-Hsien; Chang, Ting-Chang; Wu, Ming-Siou; Hung, Yi-Syuan; Hung, Pei-Hua; Hsieh, Tien-Yu; Chou, Wu-Ching; Chu, Ann-Kuo; Sze, Simon M.; Yeh, Bo-Liang

    2014-03-01

    This Letter investigates abnormal channel width-dependent threshold voltage variation in amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors. Unlike drain-induced source barrier lowering effect, threshold voltage increases with increasing drain voltage. Furthermore, the wider the channel, the larger the threshold voltage observed. Because of the surrounding oxide and other thermal insulating material and the low thermal conductivity of the IGZO layer, the self-heating effect will be pronounced in wider channel devices and those with a larger operating drain bias. To further clarify the physical mechanism, fast IV measurement is utilized to demonstrate the self-heating induced anomalous channel width-dependent threshold voltage variation.

  18. Activity of Palythoa caribaeorum Venom on Voltage-Gated Ion Channels in Mammalian Superior Cervical Ganglion Neurons

    PubMed Central

    Lazcano-Pérez, Fernando; Castro, Héctor; Arenas, Isabel; García, David E.; González-Muñoz, Ricardo; Arreguín-Espinosa, Roberto

    2016-01-01

    The Zoanthids are an order of cnidarians whose venoms and toxins have been poorly studied. Palythoa caribaeorum is a zoanthid commonly found around the Mexican coastline. In this study, we tested the activity of P. caribaeorum venom on voltage-gated sodium channel (NaV1.7), voltage-gated calcium channel (CaV2.2), the A-type transient outward (IA) and delayed rectifier (IDR) currents of KV channels of the superior cervical ganglion (SCG) neurons of the rat. These results showed that the venom reversibly delays the inactivation process of voltage-gated sodium channels and inhibits voltage-gated calcium and potassium channels in this mammalian model. The compounds responsible for these effects seem to be low molecular weight peptides. Together, these results provide evidence for the potential use of zoanthids as a novel source of cnidarian toxins active on voltage-gated ion channels. PMID:27164140

  19. 250 kV 6 mA compact Cockcroft-Walton high-voltage power supply

    NASA Astrophysics Data System (ADS)

    Ma, Zhan-Wen; Su, Xiao-Dong; Lu, Xiao-Long; Wei, Zhen; Wang, Jun-Run; Huang, Zhi-Wu; Miao, Tian-You; Su, Tong-Ling; Yao, Ze-En

    2016-08-01

    A compact power supply system for a compact neutron generator has been developed. A 4-stage symmetrical Cockcroft-Walton circuit is adopted to produce 250 kV direct current high-voltage. A 2-stage 280 kV isolation transformer system is used to drive the ion source power supply. For a compact structure, safety, and reliability during the operation, the Cockcroft-Walton circuit and the isolation transformer system are enclosed in an epoxy vessel containing the transformer oil whose size is about ∅350 mm × 766 mm. Test results indicate that the maximum output voltage of the power supply is 282 kV, and the stability of the output voltage is better than 0.63% when the high voltage power supply is operated at 250 kV, 6.9 mA with the input voltage varying ±10%.

  20. 250 kV 6 mA compact Cockcroft-Walton high-voltage power supply.

    PubMed

    Ma, Zhan-Wen; Su, Xiao-Dong; Lu, Xiao-Long; Wei, Zhen; Wang, Jun-Run; Huang, Zhi-Wu; Miao, Tian-You; Su, Tong-Ling; Yao, Ze-En

    2016-08-01

    A compact power supply system for a compact neutron generator has been developed. A 4-stage symmetrical Cockcroft-Walton circuit is adopted to produce 250 kV direct current high-voltage. A 2-stage 280 kV isolation transformer system is used to drive the ion source power supply. For a compact structure, safety, and reliability during the operation, the Cockcroft-Walton circuit and the isolation transformer system are enclosed in an epoxy vessel containing the transformer oil whose size is about ∅350 mm × 766 mm. Test results indicate that the maximum output voltage of the power supply is 282 kV, and the stability of the output voltage is better than 0.63% when the high voltage power supply is operated at 250 kV, 6.9 mA with the input voltage varying ±10%.

  1. Activity of Palythoa caribaeorum Venom on Voltage-Gated Ion Channels in Mammalian Superior Cervical Ganglion Neurons.

    PubMed

    Lazcano-Pérez, Fernando; Castro, Héctor; Arenas, Isabel; García, David E; González-Muñoz, Ricardo; Arreguín-Espinosa, Roberto

    2016-01-01

    The Zoanthids are an order of cnidarians whose venoms and toxins have been poorly studied. Palythoa caribaeorum is a zoanthid commonly found around the Mexican coastline. In this study, we tested the activity of P. caribaeorum venom on voltage-gated sodium channel (NaV1.7), voltage-gated calcium channel (CaV2.2), the A-type transient outward (IA) and delayed rectifier (IDR) currents of KV channels of the superior cervical ganglion (SCG) neurons of the rat. These results showed that the venom reversibly delays the inactivation process of voltage-gated sodium channels and inhibits voltage-gated calcium and potassium channels in this mammalian model. The compounds responsible for these effects seem to be low molecular weight peptides. Together, these results provide evidence for the potential use of zoanthids as a novel source of cnidarian toxins active on voltage-gated ion channels. PMID:27164140

  2. Observation of Voltage Oscillations in VO2 with Negative Differential Resistance

    NASA Astrophysics Data System (ADS)

    Kang, Dae-Joon; Yang, Hyoung Woo; Bae, Garam

    Many strongly correlated electron systems exhibit complex nonlinear behaviors with electric fields. The origin of the electrical instabilities is closely related to a negative differential resistance (NDR). Here, we report electrical characteristics of two-terminal devices based on vanadium dioxide (VO2) thin films fabricated on c-cut sapphire substrates, exhibiting NDR behavior in their I-V characteristics that may work as a voltage oscillator of high efficiency. We show that the NDR behavior can be better understood in the context of metal-insulator phase transition. Furthermore, we found that the source voltage and frequency affect greatly the NDR behaviors, which is indicated by an evident shift of oscillation voltage from 10 V to 1 V. Based on the experimental results, with the source voltage and the frequency systematically varied, the mechanism of the oscillation was found to be the ascribed to an alternate occurrence of an electric-field-induced resistance switching in the MIT of VO2. We discuss herein, the origin and potential applications of NDR based devices in detail and investigated the voltage oscillation behaviors of VO2 to elucidate the underlying physics of its metal insulator transition behavior.

  3. A new curvature compensation technique for CMOS voltage reference using |VGS| and ΔVBE

    NASA Astrophysics Data System (ADS)

    Xuemin, Li; Mao, Ye; Gongyuan, Zhao; Yun, Zhang; Yiqiang, Zhao

    2016-05-01

    A new mixed curvature compensation technique for CMOS voltage reference is presented, which resorts to two sub-references with complementary temperature characteristics. The first sub-reference is the source-gate voltage |VGS|p of a PMOS transistor working in the saturated region. The second sub-reference is the weighted sum of gate-source voltages |VGS|n of NMOS transistors in the subthreshold region and the difference between two base-emitter voltages ΔVBE of bipolar junction transistors (BJTs). The voltage reference implemented utilizing the proposed curvature compensation technique exhibits a low temperature coefficient and occupies a small silicon area. The proposed technique was verified in 0.18 μm standard CMOS process technology. The performance of the circuit has been measured. The measured results show a temperature coefficient as low as 12.7 ppm/°C without trimming, over a temperature range from -40 to 120 °C, and the current consumption is 50 μA at room temperature. The measured power-supply rejection ratio (PSRR) is -31.2 dB @ 100 kHz. The circuit occupies an area of 0.045 mm2. Project supported by the National Natural Science Foundation of China (No. 61376032).

  4. SAXS investigation of a cubic to a sponge (L3) phase transition in self-assembled lipid nanocarriers.

    PubMed

    Angelov, Borislav; Angelova, Angelina; Mutafchieva, Rada; Lesieur, Sylviane; Vainio, Ulla; Garamus, Vasil M; Jensen, Grethe V; Pedersen, Jan Skov

    2011-02-28

    The encapsulation and release of peptides, proteins, nucleic acids, and drugs in nanostructured lipid carriers depend on the type of the self-assembled liquid-crystalline organization and the structural dimensions of the aqueous and membraneous compartments, which can be tuned by the multicomponent composition of the systems. In this work, small-angle X-ray scattering (SAXS) investigation is performed on the 'melting' transition of the bicontinuous double diamond cubic phase, formed by pure glycerol monooleate (MO), upon progressive inclusion of varying fractions of pharmaceutical-grade glycerol monooleate (GO) in the hydrated system. The self-assembled MO/GO mixtures are found to form diamond (Pn3m) inverted cubic, inverted hexagonal (H(II)), and sponge (L(3)) phases at ambient temperature in excess of aqueous medium without heat treatment. Mixing of the inverted-cubic-phase-forming MO and the sponge-phase-forming GO components, in equivalent proportions (50/50 w/w), yields an inverted hexagonal (H(II)) phase nanostructured carrier. Scattering models are applied for fitting of the experimental SAXS patterns and identification of the structural changes in the aqueous and lipid bilayer subcompartments. The possibility of transforming, at ambient temperature (20 °C), the bicontinuous cubic nanostructures into inverted hexagonal (H(II)) or sponge (L(3)) mesophases may facilitate novel biomedical applications of the investigated liquid crystalline self-assemblies. PMID:21079857

  5. Electro-optic voltage sensor for sensing voltage in an E-field

    DOEpatents

    Woods, Gregory K.; Renak, Todd W.

    1999-01-01

    A miniature electro-optic voltage sensor system capable of accurate operation at high voltages. The system employs a transmitter, a sensor disposed adjacent to but out of direct electrical contact with a conductor on which the voltage is to be measured, a detector, and a signal processor. The transmitter produces a beam of electromagnetic radiation which is routed into the sensor where the beam undergoes the Pockels electro-optic effect. The electro-optic effect causes phase shifting in the beam, which is in turn converted to a pair of independent beams, from which the voltage of a system based on its E-field is determined when the two beams are normalized by the signal processor. The sensor converts the beam by splitting the beam in accordance with the axes of the beam's polarization state (an ellipse whose ellipticity varies between -1 and +1 in proportion to voltage) into at least two AM signals. These AM signals are fed into a signal processor and processed to determine the voltage between a ground conductor and the conductor on which voltage is being measured.

  6. Electro-optic voltage sensor for sensing voltage in an E-field

    DOEpatents

    Woods, G.K.; Renak, T.W.

    1999-04-06

    A miniature electro-optic voltage sensor system capable of accurate operation at high voltages is disclosed. The system employs a transmitter, a sensor disposed adjacent to but out of direct electrical contact with a conductor on which the voltage is to be measured, a detector, and a signal processor. The transmitter produces a beam of electromagnetic radiation which is routed into the sensor where the beam undergoes the Pockels electro-optic effect. The electro-optic effect causes phase shifting in the beam, which is in turn converted to a pair of independent beams, from which the voltage of a system based on its E-field is determined when the two beams are normalized by the signal processor. The sensor converts the beam by splitting the beam in accordance with the axes of the beam`s polarization state (an ellipse whose ellipticity varies between -1 and +1 in proportion to voltage) into at least two AM signals. These AM signals are fed into a signal processor and processed to determine the voltage between a ground conductor and the conductor on which voltage is being measured. 18 figs.

  7. 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.

  8. Group 3: Humidity, Temperature and Voltage (Presentation)

    SciTech Connect

    Wohlgemuth, J.

    2013-09-01

    This is a summary of the work of Group 3 of the International PV QA Task Force. Group 3 is chartered to develop accelerated stress tests that can be used as comparative predictors of module lifetime versus stresses associated with humidity, temperature and voltage.

  9. Voltage control on a train system

    DOEpatents

    Gordon, Susanna P.; Evans, John A.

    2004-01-20

    The present invention provides methods for preventing low train voltages and managing interference, thereby improving the efficiency, reliability, and passenger comfort associated with commuter trains. An algorithm implementing neural network technology is used to predict low voltages before they occur. Once voltages are predicted, then multiple trains can be controlled to prevent low voltage events. Further, algorithms for managing inference are presented in the present invention. Different types of interference problems are addressed in the present invention such as "Interference During Acceleration", "Interference Near Station Stops", and "Interference During Delay Recovery." Managing such interference avoids unnecessary brake/acceleration cycles during acceleration, immediately before station stops, and after substantial delays. Algorithms are demonstrated to avoid oscillatory brake/acceleration cycles due to interference and to smooth the trajectories of closely following trains. This is achieved by maintaining sufficient following distances to avoid unnecessary braking/accelerating. These methods generate smooth train trajectories, making for a more comfortable ride, and improve train motor reliability by avoiding unnecessary mode-changes between propulsion and braking. These algorithms can also have a favorable impact on traction power system requirements and energy consumption.

  10. 30 CFR 18.47 - Voltage limitation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... § 18.47 Voltage limitation. (a) A tool or switch held in the operator's hand or supported against his... current. (b) A battery-powered machine shall not have a nameplate rating exceeding 240 volts, nominal (120 lead-acid cells or equivalent). (c) Other direct-current machines shall not have a nameplate...

  11. A compact transportable Josephson voltage standard

    SciTech Connect

    Hamilton, C.A.; Burroughs, C.J.; Kupferman, S.L.

    1996-06-01

    The development of a compact, portable 10 V Josephson calibration system is described. Its accuracy is the same as typical laboratory systems and its weight and volume are reduced by more than a factor of three. The new system will replace travelling voltage standards used within several NASA and DOE standards laboratories.

  12. 49 CFR 234.221 - Lamp voltage.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Lamp voltage. 234.221 Section 234.221 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SIGNAL SYSTEM SAFETY AND STATE ACTION PLANS...

  13. 49 CFR 234.221 - Lamp voltage.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Lamp voltage. 234.221 Section 234.221 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SIGNAL SYSTEM SAFETY AND STATE ACTION PLANS...

  14. Module voltage isolation and corrosion research

    NASA Technical Reports Server (NTRS)

    Mon, G. R.

    1985-01-01

    A summary of recent research at JPL on two topics related to achieving long term reliability of photovoltaic modules: voltage isolation and electrochemical corrosion is presented. Special emphasis is given to similarities and differences in performance between crystalline silicon modules and amorphous silicon modules.

  15. Recommended practices for encapsulating high voltage assemblies

    NASA Technical Reports Server (NTRS)

    Tankisley, E. W.

    1974-01-01

    Preparation and encapsulation of high voltage assemblies are considered. Related problems in encapsulating are brought out in these instructions. A test sampling of four frequently used encapsulating compounds is shown in table form. The purpose of this table is to give a general idea of the working time available and the size of the container required for mixing and de-aerating.

  16. Gating systems for high voltage thyristor valves

    SciTech Connect

    Lips, H.P.; Pauli, M. )

    1988-07-01

    The requirements on gating systems for thyristor valves used in High Voltage Direct Current and Static Var Compensator systems are listed. Different techniques used to meet these requirements are discussed with a view on the specific service condition of the particular application and illustrated by service performance.

  17. Stray voltage and milk quality: a review.

    PubMed

    Reinemann, Douglas J

    2012-07-01

    If animal contact voltage reaches sufficient levels, animals coming into contact with grounded devices may receive a mild electric shock that can cause a behavioral response. At voltage levels that are just perceptible to the animal, behaviors indicative of perception (eg, flinches) may result with little change in normal routines. At higher exposure levels, avoidance behaviors may result. The direct effect of animal contact with electrical current can range from: • Mild behavioral reactions indicative of sensation, to • Involuntary muscle contraction, or twitching, to • Intense behavioral responses indicative of pain. The indirect effects of these behaviors can vary considerably depending on the specifics of the contact location, level of current flow, body pathway, frequency of occurrence, and many other factors related to the daily activities of animals. There are several common situations of concern in animal environments: • Animals avoiding certain exposure locations, which may result in: X Reduced water intake if exposure is required for animals to access watering devices, X Reduced feed intake if exposure is required for animals to accesses feeding devices or locations. • Difficulty of moving or handling animals in areas of voltage/current exposure• The physiologic implications of the release of stress hormones produced by contact with painful stimuli. The severity of response will depend on the amount of electrical current (measured in milliamps) flowing through the animal’s body, the pathway it takes through the body, and the sensitivity of the individual animal. The results of the combined current dose-response experiments, voltage exposure response experiments, and measurements of body and contact resistances is consistent with the lowest (worst case) cow + contact resistance as low as 500 as estimated by Lefcourt that may occur in some unusual situations on farms (firm application of the muzzle to a wet metallic watering device and hoof

  18. Potted High Voltage Modules For Space Application

    NASA Astrophysics Data System (ADS)

    Herty, Frank

    2011-10-01

    The European Space Mission GOCE, the Mercury mis- sion BepiColombo and the new High Efficiency Multistage Plasma (HEMP) thruster for the SGEO telecom mission have triggered the development of high voltage power supplies at Astrium Satellites covering different classes of output power (20W up to 1.4kW) and voltages (1kV up to 10kV). These supplies are equipped with encapsulated high voltage modules which have been designed as core functional blocks. The potting material - based on epoxy resin - was developed by Astrium Satellites. It is space-qualified for more than 30 years. Many types of high voltage modules have been manufactured since then, starting from transformer modules for the ERS mission to the modules used for electric propulsion. Technical trends, improvements and future goals of this technology are presented and discussed. New and re- fined processes are presented like the encapsulation of high-power toroidal transformers and the void-free electrical shielding by means of thin copper sheets which are laminated onto the surface of the potting material.

  19. 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

  20. High voltage pulse generator. [Patent application

    DOEpatents

    Fasching, G.E.

    1975-06-12

    An improved high-voltage pulse generator is described 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 the first rectifier connected between the first and second 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. The output voltage can be readily increased by adding additional charging networks. The circuit allows the peak level of the output to be easily varied over a wide range by using a variable autotransformer in the charging circuit.

  1. Surface voltage gradient role in high voltage solar array-plasma interaction: Center Director's discretionary fund

    NASA Technical Reports Server (NTRS)

    Carruth, M. R., Jr.

    1985-01-01

    A large amount of experimental and analytical effort has been directed toward understanding the plasma sheath growth and discharge phenomena which lead to high voltage solar array-space plasma interactions. An important question which has not been addressed is how the surface voltage gradient on such an array may affect these interactions. The results of this study indicate that under certain conditions, the voltage gradient should be taken into account when evaluating the effect on a solar array operating in a plasma environment.

  2. Bias voltage dependence of the electron spin depolarization in quantum wires in the quantum Hall regime detected by the resistively detected NMR

    SciTech Connect

    Chida, K.; Yamauchi, Y.; Arakawa, T.; Kobayashi, K.; Ono, T.; Hashisaka, M.; Nakamura, S.; Machida, T.

    2013-12-04

    We performed the resistively-detected nuclear magnetic resonance (RDNMR) to study the electron spin polarization in the non-equilibrium quantum Hall regime. By measuring the Knight shift, we derive source-drain bias voltage dependence of the electron spin polarization in quantum wires. The electron spin polarization shows minimum value around the threshold voltage of the dynamic nuclear polarization.

  3. Method and apparatus for remote tube crevice detection by current and voltage probe resistance measurement

    DOEpatents

    Kikta, T.J.; Mitchell, R.D.

    1992-11-24

    A method and apparatus for determining the extent of contact between an electrically conducting tube and an electrically conductive tubesheet surrounding the tube, based upon the electrical resistance of the tube and tubesheet. A constant current source is applied to the interior of the electrically conducting tube by probes and a voltmeter is connected between other probes to measure the voltage at the point of current injection, which is inversely proportional to the amount of contact between the tube and tubesheet. Namely, the higher the voltage measured by the voltmeter, the less contact between the tube and tubesheet. 4 figs.

  4. Method and apparatus for remote tube crevice detection by current and voltage probe resistance measurement

    DOEpatents

    Kikta, Thomas J.; Mitchell, Ronald D.

    1992-01-01

    A method and apparatus for determining the extent of contact between an electrically conducting tube and an electrically conductive tubesheet surrounding the tube, based upon the electrical resistance of the tube and tubesheet. A constant current source is applied to the interior of the electrically conducting tube by probes and a voltmeter is connected between other probes to measure the voltage at the point of current injection, which is inversely proportional to the amount of contact between the tube and tubesheet. Namely, the higher the voltage measured by the voltmeter, the less contact between the tube and tubesheet.

  5. 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.

  6. High Voltage Dielectrophoretic and Magnetophoretic Hybrid Integrated Circuit / Microfluidic Chip

    PubMed Central

    Issadore, David; Franke, Thomas; Brown, Keith A.; Hunt, Thomas P.; Westervelt, Robert M.

    2010-01-01

    A hybrid integrated circuit (IC) / microfluidic chip is presented that independently and simultaneously traps and moves microscopic objects suspended in fluid using both electric and magnetic fields. This hybrid chip controls the location of dielectric objects, such as living cells and drops of fluid, on a 60 × 61 array of pixels that are 30 × 38 μm2 in size, each of which can be individually addressed with a 50 V peak-to-peak, DC to 10 MHz radio frequency voltage. These high voltage pixels produce electric fields above the chip’s surface with a magnitude , resulting in strong dielectrophoresis (DEP) forces . Underneath the array of DEP pixels there is a magnetic matrix that consists of two perpendicular sets of 60 metal wires running across the chip. Each wire can be sourced with 120 mA to trap and move magnetically susceptible objects using magnetophoresis (MP). The DEP pixel array and magnetic matrix can be used simultaneously to apply forces to microscopic objects, such as living cells or lipid vesicles, that are tagged with magnetic nanoparticles. The capabilities of the hybrid IC / microfluidic chip demonstrated in this paper provide important building blocks for a platform for biological and chemical applications. PMID:20625468

  7. Voltage-Biased Magnetic Sensors Based on Tuned Varistors

    NASA Astrophysics Data System (ADS)

    Pandey, R. K.; Stapleton, William. A.; Sutanto, Ivan; Shamsuzzoha, M.

    2015-04-01

    In this paper, we explore the possibility of finding practical applications when the nonlinear current-voltage ( I- V) characteristics of a varistor are modified by the application of external magnetic fields. With this goal in mind, varistors based on a pseudobrookite oxide semiconductor have been studied. Pseudobrookite (PsB) is a wide bandgap n-type semiconductor with the bandgap of 2.77 eV. It is also weakly ferromagnetic. The "voltage-dependent resistor" (VDR) mode of the magnetically-tuned pseudobrookite varistors offers an opportunity to advance magnetic sensor technology. The resistive and magnetoresistive parameters of PsB VDRs exhibit good responses to applied magnetic fields and they can therefore be the basis for the fabrication of simple yet practical magnetic sensors. These sensors can cover the range of magnetic fields between 0 and 4500 Oe with good accuracy, and could possibly be considered as a substitute for Hall Effect-based sensors for many applications. Also, due to their simple structure, they would be rugged and not susceptible to abuses. They may also be suitable for applications in hazardous environments such as high temperatures and atmospheres having the presence of radiation, such as neutrons, protons, etc. It is also possible that these novel sensors could be suitable for geological applications such as in well logging in search of energy sources.

  8. Understanding High Voltage Vacuum Insulators for Microsecond Pulses

    SciTech Connect

    J.B., J; D.A., G; T.L., H; E.J., L; R.D., S; L.K., T; G.E., V

    2007-08-15

    High voltage insulation is one of the main areas of pulsed power research and development since the surface of an insulator exposed to vacuum can fail electrically at an applied field more than an order or magnitude below the bulk dielectric strength of the insulator. This is troublesome for applications where high voltage conditioning of the insulator and electrodes is not practical and where relatively long pulses, on the order of several microseconds, are required. Here we give a summary of our approach to modeling and simulation efforts and experimental investigations for understanding flashover mechanism. The computational work is comprised of both filed and particle-in-cell modeling with state-of-the-art commercial codes. Experiments were performed in using an available 100-kV, 10-{micro}s pulse generator and vacuum chamber. The initial experiments were done with polyethylene insulator material in the shape of a truncated cone cut at +45{sup o} angle between flat electrodes with a gap of 1.0 cm. The insulator was sized so there were no flashovers or breakdowns under nominal operating conditions. Insulator flashover or gap closure was induced by introducing a plasma source, a tuft of velvet, in proximity to the insulator or electrode.

  9. Eliminating Voltage Decay of Lithium-Rich Li1.14Mn0.54Ni0.14Co0.14O2 Cathodes by Controlling the Electrochemical Process

    DOE PAGES

    Wei, Z.; Zhu, Y.; Zhang, W.; Wang, F.; Zhang, Q.; Qiu, B.; Han, S.; Xia, Y.; Liu, Z.

    2015-03-27

    Lithium-rich material owns a particularly high capacity owing to the activation of electrochemical inactive Li2MnO3 phase. But at the same time, MnO2 phase formed after Li2MnO3 activation confronts a severe problem of converting to spinel phase, and resulting in voltage decay. To our knowledge, this phenomenon is inherent property of layered manganese oxide materials and can hardly be overcome. Based on this, unlike previous reports, herein we design a method for the first time to accelerate the phase transformation by tuning the charge upper-limit voltage at a high value, so the phase transformation process can be finished in a fewmore » cycles. Then material structure remains stable while cycling at a low upper-limit voltage. By this novel method voltage decay is eliminated significantly.« less

  10. Optimization of power system voltage stability

    NASA Astrophysics Data System (ADS)

    Stamp, Jason Edwin

    Contemporary power systems exist under heavy stress, caused by higher asset utilization in electric power transmission. As networks are operated nearer to their limits, new stability issues have arisen. One of the more destructive problems is voltage instability, where large areas of an electrical network may experience reduced voltages or collapse because of high reactive power demand. Voltage stability margins may be improved through the adjustment of the system operating position, which alters the power flow profile of the transmission network. Furthermore, the margins may be optimized through the application of nonlinear programming, if they are quantified using an index of voltage collapse proximity. This dissertation details the maximization of the eigenvalues of the reduced reactive power-voltage matrix, in an effort to increase voltage security. The nonlinear optimization was solved using four different techniques. First, a conventional optimal power flow was applied to the problem, which solved linear approximations of the original problem and maintained feasibility for the intermediate points. This method was augmented to include a quadratic model of the objective function. In addition, the feasibility requirement was relaxed to produce a third solution technique. Finally, the stability optimization problem was solved using a quadratic model without the feasibility requirement. Tests of all four methods were performed on three sample power systems. The systems included six, 14, and 118 bus examples. In all three cases, each of the four methods effected improvement in the stability margin, as measured by a variety of indicators. The infeasible linear solution provided the best results, based on runtime and the relative stability improvement. Also, the results showed that the additional quadratic approximation did not provide any measurable benefit to the procedure. Moreover, the methods that specified feasibility at each step were inferior compared to the

  11. Varactor with integrated micro-discharge source

    DOEpatents

    Elizondo-Decanini, Juan M.; Manginell, Ronald P.; Moorman, Matthew W.

    2016-10-18

    An apparatus that includes a varactor element and an integrated micro-discharge source is disclosed herein. In a general embodiment, the apparatus includes at least one np junction and at least one voltage source that is configured to apply voltage across the np junction. The apparatus further includes an aperture that extends through the np junction. When the voltage is applied across the np junction, gas in the aperture is ionized, forming a plasma, in turn causing a micro-discharge (of light, charge particles, and space charge) to occur. The light (charge particles, and space charge) impinges upon the surface of the np junction exposed in the aperture, thereby altering capacitance of the np junction. When used within an oscillator circuit, the effect of the plasma on the np-junction extends the capacitance changes of the np-junction and extends the oscillator frequency range in ways not possible by a conventional voltage controlled oscillator (VCO).

  12. Thermo-voltage measurements of atomic contacts at low temperature.

    PubMed

    Ofarim, Ayelet; Kopp, Bastian; Möller, Thomas; Martin, León; Boneberg, Johannes; Leiderer, Paul; Scheer, Elke

    2016-01-01

    We report the development of a novel method to determine the thermopower of atomic-sized gold contacts at low temperature. For these measurements a mechanically controllable break junction (MCBJ) system is used and a laser source generates a temperature difference of a few kelvins across the junction to create a thermo-voltage. Since the temperature difference enters directly into the Seebeck coefficient S = -ΔV/ΔT, the determination of the temperature plays an important role. We present a method for the determination of the temperature difference using a combination of a finite element simulation, which reveals the temperature distribution of the sample, and the measurement of the resistance change due to laser heating of sensor leads on both sides next to the junction. Our results for the measured thermopower are in agreement with recent reports in the literature.

  13. Thermo-voltage measurements of atomic contacts at low temperature

    PubMed Central

    Ofarim, Ayelet; Kopp, Bastian; Möller, Thomas; Martin, León; Boneberg, Johannes; Leiderer, Paul

    2016-01-01

    Summary We report the development of a novel method to determine the thermopower of atomic-sized gold contacts at low temperature. For these measurements a mechanically controllable break junction (MCBJ) system is used and a laser source generates a temperature difference of a few kelvins across the junction to create a thermo-voltage. Since the temperature difference enters directly into the Seebeck coefficient S = −ΔV/ΔT, the determination of the temperature plays an important role. We present a method for the determination of the temperature difference using a combination of a finite element simulation, which reveals the temperature distribution of the sample, and the measurement of the resistance change due to laser heating of sensor leads on both sides next to the junction. Our results for the measured thermopower are in agreement with recent reports in the literature. PMID:27335765

  14. Remote renewable energy resources; Long-distance high voltage interconnections

    SciTech Connect

    Hammons, T.J. )

    1992-06-01

    This paper discusses international perspectives on remote energy made possible by high-voltage interconnections. It will discuss large-scale conversion, transfer, and utilization of renewable energy as a strategy to counter environmental problems caused by the combustion of fossil fuels. Potential development of huge renewable hydro resources in Africa, South America, North America, Eastern Siberia, Australia, and South East China, as well as potential development of geothermal and solar energy sources, will also be discussed. These include the proposed 30 GW Inga hydro power complex in Zaire, Central Africa, along the Congo River, where power will be exported to Southern Europe over a distance of 7000 Km, in Columbia with electrical ties through Central America linking South America with the electricity demand in North America, and developments in Siberia linked by cable across the Bering Strait to Alaska, Quebec to New England, Manitoba to midwest United States, Iceland to the United Kingdom, and in the Persian Gulf States.

  15. Voltage Stability Impact of Grid-Tied Photovoltaic Systems Utilizing Dynamic Reactive Power Control

    NASA Astrophysics Data System (ADS)

    Omole, Adedamola

    Photovoltaic (PV) DGs can be optimized to provide reactive power support to the grid, although this feature is currently rarely utilized as most DG systems are designed to operate with unity power factor and supply real power only to the grid. In this work, the voltage stability of a power system embedded with PV DG is examined in the context of the high reactive power requirement after a voltage sag or fault. A real-time dynamic multi-function power controller that enables renewable source PV DGs to provide the reactive power support necessary to maintain the voltage stability of the microgrid, and consequently, the wider power system is proposed. The loadability limit necessary to maintain the voltage stability of an interconnected microgrid is determined by using bifurcation analysis to test for the singularity of the network Jacobian and load differential equations with and without the contribution of the DG. The maximum and minimum real and reactive power support permissible from the DG is obtained from the loadability limit and used as the limiting factors in controlling the real and reactive power contribution from the PV source. The designed controller regulates the voltage output based on instantaneous power theory at the point-of-common coupling (PCC) while the reactive power supply is controlled by means of the power factor and reactive current droop method. The control method is implemented in a modified IEEE 13-bus test feeder system using PSCADRTM power system analysis software and is applied to the model of a Tampa ElectricRTM PV installation at Lowry Park Zoo in Tampa, FL. This dissertation accomplishes the systematic analysis of the voltage impact of a PV DG-embedded power distribution system. The method employed in this work bases the contribution of the PV resource on the voltage stability margins of the microgrid rather than the commonly used loss-of-load probability (LOLP) and effective load-carrying capability (ELCC) measures. The results of

  16. Development of a quantum-voltage-calibrated noise thermometer at NIM

    SciTech Connect

    Qu, J.; Zhang, J. T.; Fu, Y.; Rogalla, H.; Pollarolo, A.; Benz, S. P.

    2013-09-11

    A quantum-voltage-calibrated Johnson-noise thermometer was developed at NIM, which measures the Boltzmann constant k by comparing the thermal noise across a 100 Ω sense resistor at the temperature of the triple point of water with the pseudo-random frequency-comb voltage waveform synthesized with a bipolar-pulse-driven quantum-voltage-noise source. A measurement with integration period of 10 hours and bandwidth of 640 kHz resulted in a relative offset of 0.5×10{sup −6} from the current CODATA value of k, and a type A relative standard uncertainty of 23×10{sup −6}. Benefiting from closely matched noise powers and transmission-line impedances and small nonlinearities in the cross-correlation electronics, the derived k shows self-consistent values and standard uncertainties for different measurement bandwidths.

  17. Considerations for ground fault protection in medium-voltage industrial and cogeneration systems

    SciTech Connect

    Love, D.J.; Hashemi, N.

    1988-07-01

    Industrial plants utilize medium-voltage systems for in-plant distribution of purchased and cogenerated electrical energy. During the planning stage, system protection is generally specified, including the type of source neutral grounding and ground fault protection. Where medium-voltage systems have expanded, circuit-breaker interrupting ratings have also been increased. Accordingly, grounding consideration should be reviewed, particularly because charging and/or ground fault current values have also increased. The typical methods for grounding of medium-voltage neutral systems - high resistance, low resistance, and ungrounded, as well as methods used to detect the presence of a ground fault - are reviewed. Also, the effects of charging current and how the ground fault protection method could affect conductor ratings are analyzed.

  18. Using phasors to analyze power system negative phase sequence voltages caused by unbalanced loads

    SciTech Connect

    Ledwich, G. ); George, T.A. )

    1994-08-01

    An analytical method is demonstrated which allows the level of negative phase sequence (NPS) voltage at a busbar to be expressed as a sum of phasors representing independent sources. The method is extended to enable the balancing capability of Static Var Compensators (SVCs) with individual phase voltage control to be assessed. The capability of such SVCs and the allowable levels of NPS voltage on the system, including any short term limits, can be combined in a capability chart showing the unbalanced loads which can be supplied from a substation. The approach facilitates the treatment of fixed unbalances due to filters or intentional offsets designed to maximize the SVC balancing range for specific loads. Field test results are presented which validate the analytical methods used.

  19. Measurement system for determination of current-voltage characteristics of PV modules

    NASA Astrophysics Data System (ADS)

    Idzkowski, Adam; Walendziuk, Wojciech; Borawski, Mateusz; Sawicki, Aleksander

    2015-09-01

    The realization of a laboratory stand for testing photovoltaic panels is presented here. The project of the laboratory stand was designed in SolidWorks software. The aim of the project was to control the electrical parameters of a PV panel. For this purpose a meter that measures electrical parameters i.e. voltage, current and power, was realized. The meter was created with the use of LabJack DAQ device and LabVIEW software. The presented results of measurements were obtained in different conditions (variable distance from the source of light, variable tilt angle of the panel). Current voltage characteristics of photovoltaic panel were created and all parameters could be detected in different conditions. The standard uncertainties of sample voltage, current, power measurements were calculated. The paper also gives basic information about power characteristics and efficiency of a solar cell.

  20. Extremum seeking-based optimization of high voltage converter modulator rise-time

    SciTech Connect

    Scheinker, Alexander; Bland, Michael; Krstic, Miroslav; Audia, Jeff

    2013-02-01

    We digitally implement an extremum seeking (ES) algorithm, which optimizes the rise time of the output voltage of a high voltage converter modulator (HVCM) at the Los Alamos Neutron Science Center (LANSCE) HVCM test stand by iteratively, simultaneously tuning the first 8 switching edges of each of the three phase drive waveforms (24 variables total). We achieve a 50 μs rise time, which is reduction in half compared to the 100 μs achieved at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory. Considering that HVCMs typically operate with an output voltage of 100 kV, with a 60Hz repetition rate, the 50 μs rise time reduction will result in very significant energy savings. The ES algorithm will prove successful, despite the noisy measurements and cost calculations, confirming the theoretical results that the algorithm is not affected by noise whose frequency components are independent of the perturbing frequencies.

  1. Development of a quantum-voltage-calibrated noise thermometer at NIM

    NASA Astrophysics Data System (ADS)

    Qu, J.; Zhang, J. T.; Fu, Y.; Rogalla, H.; Pollarolo, A.; Benz, S. P.

    2013-09-01

    A quantum-voltage-calibrated Johnson-noise thermometer was developed at NIM, which measures the Boltzmann constant k by comparing the thermal noise across a 100 Ω sense resistor at the temperature of the triple point of water with the pseudo-random frequency-comb voltage waveform synthesized with a bipolar-pulse-driven quantum-voltage-noise source. A measurement with integration period of 10 hours and bandwidth of 640 kHz resulted in a relative offset of 0.5×10-6 from the current CODATA value of k, and a type A relative standard uncertainty of 23×10-6. Benefiting from closely matched noise powers and transmission-line impedances and small nonlinearities in the cross-correlation electronics, the derived k shows self-consistent values and standard uncertainties for different measurement bandwidths.

  2. Design issues for lateral double-diffused metal-oxide-semiconductor with higher breakdown voltage.

    PubMed

    Sung, Kunsik; Won, Taeyoung

    2013-05-01

    In this paper, we discuss a new High-Side nLDMOSFET whose breakdown voltage is over 100 V while meeting the thermal budget for the conventional process. The proposed n-channel lateral double-diffused metal-oxide-semiconductor field-effect transistor (LDMOSFET) has a feature in that the structure comprises a gap of 5 microm between the DEEP N-WELL and the center of the source, the surface of which is implanted by the NADJUST-layer for high breakdown voltage and simultaneously the low specific on-resistance. The computer simulation of the proposed High-Side nLDMOS exhibits BVdss of 126 V and R(ON,sp) of as low as 2.50 m(omega) x cm2. The NBL, which plays a significant role as a blocking layer against the punch-through seems to function as a hurdle for increasing the breakdown voltage. PMID:23858840

  3. High-voltage testing of a 500-kV dc photocathode electron gun.

    PubMed

    Nagai, Ryoji; Hajima, Ryoichi; Nishimori, Nobuyuki; Muto, Toshiya; Yamamoto, Masahiro; Honda, Yosuke; Miyajima, Tsukasa; Iijima, Hokuto; Kuriki, Masao; Kuwahara, Makoto; Okumi, Shoji; Nakanishi, Tsutomu

    2010-03-01

    A high-voltage dc photocathode electron gun was successfully conditioned up to a voltage of 550 kV and a long-time holding test for 8 h was demonstrated at an acceleration voltage of 500 kV. The dc photocathode electron gun is designed for future light sources based on energy-recovery linac and consists of a Cockcroft-Walton generator, a segmented cylindrical ceramic insulator, guard-ring electrodes, a support-rod electrode, a vacuum chamber, and a pressurized insulating gas tank. The segmented cylindrical ceramic insulator and the guard-ring electrodes were utilized to prevent any damage to the insulator from electrons emitted by the support-rod electrode.

  4. Pulsed source ion implantation apparatus and method

    DOEpatents

    Leung, K.N.

    1996-09-24

    A new pulsed plasma-immersion ion-implantation apparatus that implants ions in large irregularly shaped objects to controllable depth without overheating the target, minimizing voltage breakdown, and using a constant electrical bias applied to the target. Instead of pulsing the voltage applied to the target, the plasma source, for example a tungsten filament or a RF antenna, is pulsed. Both electrically conducting and insulating targets can be implanted. 16 figs.

  5. Pulsed source ion implantation apparatus and method

    DOEpatents

    Leung, Ka-Ngo

    1996-01-01

    A new pulsed plasma-immersion ion-implantation apparatus that implants ions in large irregularly shaped objects to controllable depth without overheating the target, minimizing voltage breakdown, and using a constant electrical bias applied to the target. Instead of pulsing the voltage applied to the target, the plasma source, for example a tungsten filament or a RF antenna, is pulsed. Both electrically conducting and insulating targets can be implanted.

  6. Energy harvesting in high voltage measuring techniques

    NASA Astrophysics Data System (ADS)

    Żyłka, Pawel; Doliński, Marcin

    2016-02-01

    The paper discusses selected problems related to application of energy harvesting (that is, generating electricity from surplus energy present in the environment) to supply autonomous ultra-low-power measurement systems applicable in high voltage engineering. As a practical example of such implementation a laboratory model of a remote temperature sensor is presented, which is self-powered by heat generated in a current-carrying busbar in HV- switchgear. Presented system exploits a thermoelectric harvester based on a passively cooled Peltier module supplying micro-power low-voltage dc-dc converter driving energy-efficient temperature sensor, microcontroller and a fibre-optic transmitter. Performance of the model in laboratory simulated conditions are presented and discussed.

  7. High voltage system: Plasma interaction summary

    NASA Technical Reports Server (NTRS)

    Stevens, N. John

    1986-01-01

    The possible interactions that could exist between a high voltage system and the space plasma environment are reviewed. A solar array is used as an example of such a system. The emphasis in this review is on the discrepancies that exist in this technology in both flight and ground experiment data. It has been found that, in ground testing, there are facility effects, cell size effects and area scaling uncertainties. For space applications there are area scaling and discharge concerns for an array as well as the influence of the large space structures on the collection process. There are still considerable uncertainties in the high voltage-space plasma interaction technology even after several years of effort.

  8. High Voltage Design Guidelines: A Timely Update

    NASA Technical Reports Server (NTRS)

    Hillard, G. Barry; Kirkici, H.; Ensworth, Clint (Technical Monitor)

    2001-01-01

    The evolving state of high voltage systems and their increasing use in the space program have called for a revision of the High Voltage Design Guidelines, Marshall Space Flight Center technical document MSFC-STD-531, originally issued September 1978 (previously 50 M05189b, October 1972). These guidelines deal in depth with issues relating to the specification of materials, particularly electrical insulation, as well as design practices and test methods. Emphasis is on corona and Paschen breakdown as well as plasma effects for Low Earth Orbiting systems. We will briefly review the history of these guidelines as well as their immediate predecessors and discuss their range of applicability. In addition, this document has served as the basis for several derived works that became focused, program-specific HV guidelines. We will briefly review two examples, guidelines prepared for the X-33 program and for the Space Shuttle Electric Auxiliary Power Unit (EAPU) upgrade.

  9. Superconducting Fault Current Limiter for Transmission Voltage

    NASA Astrophysics Data System (ADS)

    Kraemer, Hans-Peter; Schmidt, Wolfgang; Cai, Hong; Gamble, Bruce; Madura, David; MacDonald, Tim; McNamara, Joe; Romanosky, Walther; Snitchler, Greg; Lallouet, Nicolas; Schmidt, Frank; Ahmed, Syed

    Within a collaboration of American Superconductor, Siemens, Nexans and Southern California Edison one electrical phase of a resistive superconducting fault current limiter for the 115 kV transmission voltage level has been designed and manufactured. The active part of the limiter consists of 63 bifilar coils made of 12 mm wide steel-stabilized YBCO conductor and is housed in a cryostat operated at 5 bar and 74 K. The first phase was completely assembled and successfully subjected to power switching tests and high voltage tests. The basic design of the system and the test results are reported. The work was funded in part by US-DOE under Contract Number DE-FC26-07NT43243.

  10. High voltage system: Plasma interaction summary

    NASA Astrophysics Data System (ADS)

    Stevens, N. John

    1986-10-01

    The possible interactions that could exist between a high voltage system and the space plasma environment are reviewed. A solar array is used as an example of such a system. The emphasis in this review is on the discrepancies that exist in this technology in both flight and ground experiment data. It has been found that, in ground testing, there are facility effects, cell size effects and area scaling uncertainties. For space applications there are area scaling and discharge concerns for an array as well as the influence of the large space structures on the collection process. There are still considerable uncertainties in the high voltage-space plasma interaction technology even after several years of effort.

  11. Sauer's non-linear voltage division.

    PubMed

    Schwan, H P; McAdams, E T; Jossinet, J

    2002-09-01

    The non-linearity of the electrode-tissue interface impedance gives rise to harmonics and thus degrades the accuracy of impedance measurements. Also, electrodes are often driven into the non-linear range of their polarisation impedance. This is particularly true in clinical applications. Techniques to correct for electrode effects are usually based on linear electrode impedance data. However, these data can be very different from the non-linear values needed. Non-linear electrode data suggested a model based on simple assumptions. It is useful in predicting the frequency dependence of non-linear effects from linear properties. Sauer's treatment is a first attempt to provide a more general and rigorous basis for modelling the non-linear state. The paper reports Sauer's treatment of the non-linear case and points out its limitations. The paper considers Sauer's treatment of a series arrangement of two impedances. The tissue impedance is represented by a linear voltage-current characteristic. The interface impedance is represented by a Volterra expansion. The response of this network to periodic signals is calculated up to the second-order term of the series expansion. The resultant, time-dependent current is found to contain a DC term (rectification), as well as frequency-dependent terms. Sauer's treatment assumes a voltage clamp across the impedances and neglects higher-order terms in the series expansion. As a consequence, it fails adequately to represent some experimentally observed phenomena. It is therefore suggested that Sauer's expressions for the voltage divider should be combined with the non-linear treatments previously published by the co-authors. Although Sauer's work on the non-linear voltage divider was originally applied to the study of the non-linear behaviour of the electrode-electrolyte interface and biological tissues, it is stressed, however, that the work is applicable to a wide range of research areas.

  12. High voltage spark carbon fiber detection system

    NASA Technical Reports Server (NTRS)

    Yang, L. C.

    1980-01-01

    The pulse discharge technique was used to determine the length and density of carbon fibers released from fiber composite materials during a fire or aircraft accident. Specifications are given for the system which uses the ability of a carbon fiber to initiate spark discharge across a high voltage biased grid to achieve accurate counting and sizing of fibers. The design of the system was optimized, and prototype hardware proved satisfactory in laboratory and field tests.

  13. 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)

  14. Printing low-voltage dielectric elastomer actuators

    NASA Astrophysics Data System (ADS)

    Poulin, Alexandre; Rosset, Samuel; Shea, Herbert R.

    2015-12-01

    We demonstrate the fabrication of fully printed thin dielectric elastomer actuators (DEAs), reducing the operation voltage below 300 V while keeping good actuation strain. DEAs are soft actuators capable of strains greater than 100% and response times below 1 ms, but they require driving voltage in the kV range, limiting the possible applications. One way to reduce the driving voltage of DEAs is to decrease the dielectric membrane thickness, which is typically in the 20-100 μm range, as reliable fabrication becomes challenging below this thickness. We report here the use of pad-printing to produce μm thick silicone membranes, on which we pad-print μm thick compliant electrodes to create DEAs. We achieve a lateral actuation strain of 7.5% at only 245 V on a 3 μm thick pad-printed membrane. This corresponds to a ratio of 125%/kV2, by far the highest reported value for DEAs. To quantify the increasing stiffening impact of the electrodes on DEA performance as the membrane thickness decreases, we compare two circular actuators, one with 3 μm- and one with 30 μm-thick membranes. Our experimental measurements show that the strain uniformity of the 3 μm-DEA is indeed affected by the mechanical impact of the electrodes. We developed a simple DEA model that includes realistic electrodes of finite stiffness, rather than assuming zero stiffness electrodes as is commonly done. The simulation results confirm that the stiffening impact of the electrodes is an important parameter that should not be neglected in the design of thin-DEAs. This work presents a practical approach towards low-voltage DEAs, a critical step for the development of real world applications.

  15. Voltage-sensitive dye recording from networks of cultured neurons

    NASA Astrophysics Data System (ADS)

    Chien, Chi-Bin

    This thesis describes the development and testing of a sensitive apparatus for recording electrical activity from microcultures of rat superior cervical ganglion (SCG) neurons by using voltage-sensitive fluorescent dyes.The apparatus comprises a feedback-regulated mercury arc light source, an inverted epifluorescence microscope, a novel fiber-optic camera with discrete photodiode detectors, and low-noise preamplifiers. Using an NA 0.75 objective and illuminating at 10 W/cm2 with the 546 nm mercury line, a typical SCG neuron stained with the styryl dye RH423 gives a detected photocurrent of 1 nA; the light source and optical detectors are quiet enough that the shot noise in this photocurrent--about.03% rms--dominates. The design, theory, and performance of this dye-recording apparatus are discussed in detail.Styryl dyes such as RH423 typically give signals of 1%/100 mV on these cells; the signals are linear in membrane potential, but do not appear to arise from a purely electrochromic mechanism. Given this voltage sensitivity and the noise level of the apparatus, it should be possible to detect both action potentials and subthreshold synaptic potentials from SCG cell bodies. In practice, dye recording can easily detect action potentials from every neuron in an SCG microculture, but small synaptic potentials are obscured by dye signals from the dense network of axons.In another microculture system that does not have such long and complex axons, this dye-recording apparatus should be able to detect synaptic potentials, making it possible to noninvasively map the synaptic connections in a microculture, and thus to study long-term synaptic plasticity.

  16. 80-GHz MMIC HEMT Voltage-Controlled Oscillator

    NASA Technical Reports Server (NTRS)

    Samoska, Lorene; Radisic, Vesna; Micovic, Miro; Hu, Ming; Janke, Paul; Ngo, Catherine; Nguyen, Loi

    2003-01-01

    A voltage-controlled oscillator (VCO) that operates in the frequency range from 77.5 to 83.5 GHz has been constructed in the form of a monolithic microwave integrated circuit (MMIC) that includes high-electron-mobility transistors (HEMTs). This circuit is a prototype of electronically tunable signal sources in the 75-to-110-GHz range, needed for communication, imaging, and automotive radar applications, among others. This oscillator (see Figure 1) includes two AlInAs/GaInAs/InP HEMTs. One HEMT serves mainly as an oscillator gain element. The other HEMT serves mainly as a varactor for controlling the frequency: the frequency-control element is its gate-to-source capacitance, which is varied by changing its gate supply voltage. The gain HEMT is biased for class-A operation (meaning that current is conducted throughout the oscillation cycle). Grounded coplanar waveguides are used as impedance-matching transmission lines, the input and output matching being chosen to sustain oscillation and maximize output power. Air bridges are placed at discontinuities to suppress undesired slot electromagnetic modes. A high density of vias is necessary for suppressing a parallel-plate electromagnetic mode that is undesired because it can propagate energy into the MMIC substrate. Previous attempts at constructing HEMT-based oscillators yielded circuits with relatively low levels of output power and narrow tuning ranges. For example, one HEMT VCO reported in the literature had an output power of 7 dBm (.5 mW) and a tuning range 2-GHz wide centered approximately at a nominal frequency of 77 GHz. In contrast, as shown in Figure 2, the present MMIC HEMT VCO puts out a power of 12.5 dBm (.18 mW) or more over the 6-GHz-wide frequency range from 77.5 to 83.5 GHz

  17. Engineering of a Genetically Encodable Fluorescent Voltage Sensor Exploiting Fast Ci-VSP Voltage-Sensing Movements

    PubMed Central

    Lundby, Alicia; Mutoh, Hiroki; Dimitrov, Dimitar; Akemann, Walther; Knöpfel, Thomas

    2008-01-01

    Ci-VSP contains a voltage-sensing domain (VSD) homologous to that of voltage-gated potassium channels. Using charge displacement (‘gating’ current) measurements we show that voltage-sensing movements of this VSD can occur within 1 ms in mammalian membranes. Our analysis lead to development of a genetically encodable fluorescent protein voltage sensor (VSFP) in which the fast, voltage-dependent conformational changes of the Ci-VSP voltage sensor are transduced to similarly fast fluorescence read-outs. PMID:18575613

  18. Voltage-gated proton channels: what' next?

    PubMed Central

    DeCoursey, Thomas E

    2008-01-01

    This review is an attempt to identify and place in context some of the many questions about voltage-gated proton channels that remain unsolved. As the gene was identified only 2 years ago, the situation is very different than in fields where the gene has been known for decades. For the proton channel, most of the obvious and less obvious structure–function questions are still wide open. Remarkably, the proton channel protein strongly resembles the voltage-sensing domain of many voltage-gated ion channels, and thus offers a novel approach to study gating mechanisms. Another surprise is that the proton channel appears to function as a dimer, with two separate conduction pathways. A number of significant biological questions remain in dispute, unanswered, or in some cases, not yet asked. This latter deficit is ascribable to the intrinsic difficulty in evaluating the importance of one component in a complex system, and in addition, to the lack, until recently, of a means of performing an unambiguous lesion experiment, that is, of selectively eliminating the molecule in question. We still lack a potent, selective pharmacological inhibitor, but the identification of the gene has allowed the development of powerful new tools including proton channel antibodies, siRNA and knockout mice. PMID:18801839

  19. Electro-optic voltage sensor head

    DOEpatents

    Crawford, T.M.; Davidson, J.R.; Woods, G.K.

    1999-08-17

    The invention is an electro-optic voltage sensor head designed for integration with existing types of high voltage transmission and distribution apparatus. The sensor head contains a transducer, which comprises a transducing material in which the Pockels electro-optic effect is observed. In the practice of the invention at least one beam of electromagnetic radiation is routed into the transducing material of the transducer in the sensor head. The beam undergoes an electro-optic effect in the sensor head when the transducing material is subjected to an E-field. The electro-optic effect is observed as a differential phase a shift, also called differential phase modulation, of the beam components in orthogonal planes of the electromagnetic radiation. In the preferred embodiment the beam is routed through the transducer along an initial axis and then reflected by a retro-reflector back substantially parallel to the initial axis, making a double pass through the transducer for increased measurement sensitivity. The preferred embodiment of the sensor head also includes a polarization state rotator and at least one beam splitter for orienting the beam along major and minor axes and for splitting the beam components into two signals which are independent converse amplitude-modulated signals carrying E-field magnitude and hence voltage information from the sensor head by way of optic fibers. 6 figs.

  20. Electro-optic voltage sensor head

    DOEpatents

    Crawford, Thomas M.; Davidson, James R.; Woods, Gregory K.

    1999-01-01

    The invention is an electro-optic voltage sensor head designed for integration with existing types of high voltage transmission and distribution apparatus. The sensor head contains a transducer, which comprises a transducing material in which the Pockels electro-optic effect is observed. In the practice of the invention at least one beam of electromagnetic radiation is routed into the transducing material of the transducer in the sensor head. The beam undergoes an electro-optic effect in the sensor head when the transducing material is subjected to an E-field. The electro-optic effect is observed as a differential phase a shift, also called differential phase modulation, of the beam components in orthogonal planes of the electromagnetic radiation. In the preferred embodiment the beam is routed through the transducer along an initial axis and then reflected by a retro-reflector back substantially parallel to the initial axis, making a double pass through the transducer for increased measurement sensitivity. The preferred embodiment of the sensor head also includes a polarization state rotator and at least one beam splitter for orienting the beam along major and minor axes and for splitting the beam components into two signals which are independent converse amplitude-modulated signals carrying E-field magnitude and hence voltage information from the sensor head by way of optic fibers.

  1. Spike voltage topography in temporal lobe epilepsy.

    PubMed

    Asadi-Pooya, Ali A; Asadollahi, Marjan; Shimamoto, Shoichi; Lorenzo, Matthew; Sperling, Michael R

    2016-07-15

    We investigated the voltage topography of interictal spikes in patients with temporal lobe epilepsy (TLE) to see whether topography was related to etiology for TLE. Adults with TLE, who had epilepsy surgery for drug-resistant seizures from 2011 until 2014 at Jefferson Comprehensive Epilepsy Center were selected. Two groups of patients were studied: patients with mesial temporal sclerosis (MTS) on MRI and those with other MRI findings. The voltage topography maps of the interictal spikes at the peak were created using BESA software. We classified the interictal spikes as polar, basal, lateral, or others. Thirty-four patients were studied, from which the characteristics of 340 spikes were investigated. The most common type of spike orientation was others (186 spikes; 54.7%), followed by lateral (146; 42.9%), polar (5; 1.5%), and basal (3; 0.9%). Characteristics of the voltage topography maps of the spikes between the two groups of patients were somewhat different. Five spikes in patients with MTS had polar orientation, but none of the spikes in patients with other MRI findings had polar orientation (odds ratio=6.98, 95% confidence interval=0.38 to 127.38; p=0.07). Scalp topographic mapping of interictal spikes has the potential to offer different information than visual inspection alone. The present results do not allow an immediate clinical application of our findings; however, detecting a polar spike in a patient with TLE may increase the possibility of mesial temporal sclerosis as the underlying etiology. PMID:27288809

  2. Spike voltage topography in temporal lobe epilepsy.

    PubMed

    Asadi-Pooya, Ali A; Asadollahi, Marjan; Shimamoto, Shoichi; Lorenzo, Matthew; Sperling, Michael R

    2016-07-15

    We investigated the voltage topography of interictal spikes in patients with temporal lobe epilepsy (TLE) to see whether topography was related to etiology for TLE. Adults with TLE, who had epilepsy surgery for drug-resistant seizures from 2011 until 2014 at Jefferson Comprehensive Epilepsy Center were selected. Two groups of patients were studied: patients with mesial temporal sclerosis (MTS) on MRI and those with other MRI findings. The voltage topography maps of the interictal spikes at the peak were created using BESA software. We classified the interictal spikes as polar, basal, lateral, or others. Thirty-four patients were studied, from which the characteristics of 340 spikes were investigated. The most common type of spike orientation was others (186 spikes; 54.7%), followed by lateral (146; 42.9%), polar (5; 1.5%), and basal (3; 0.9%). Characteristics of the voltage topography maps of the spikes between the two groups of patients were somewhat different. Five spikes in patients with MTS had polar orientation, but none of the spikes in patients with other MRI findings had polar orientation (odds ratio=6.98, 95% confidence interval=0.38 to 127.38; p=0.07). Scalp topographic mapping of interictal spikes has the potential to offer different information than visual inspection alone. The present results do not allow an immediate clinical application of our findings; however, detecting a polar spike in a patient with TLE may increase the possibility of mesial temporal sclerosis as the underlying etiology.

  3. Interface connections of a transmembrane voltage sensor.

    PubMed

    Freites, J Alfredo; Tobias, Douglas J; von Heijne, Gunnar; White, Stephen H

    2005-10-18

    Voltage-sensitive ion channels open and close in response to changes in transmembrane (TM) potential caused by the motion of the S4 voltage sensors. These sensors are alpha-helices that include four or more positively charged amino acids, most commonly arginine. The so-called paddle model, based on the high-resolution structure of the KvAP K+ channel [Jiang, et al. (2003) Nature 423, 33-41], posits that the S4 sensors move within the membrane bilayer in response to TM voltage changes. Direct exposure of S4 sensors to lipid is contrary to the classical expectation that the dielectric contrast between the membrane hydrocarbon core and water presents an insurmountable energetic penalty to burial of electric charges. Nevertheless, recent experiments have shown that a helix with the sequence of KvAP S4 can be inserted across the endoplasmic reticulum membrane. To reconcile this result with the classical energetics argument, we have carried out a molecular dynamics simulation of an isolated TM S4 helix in a lipid bilayer. The simulation reveals a stabilizing hydrogen-bonded network of water and lipid phosphates around the arginines that reduces the effective thickness of the bilayer hydrocarbon core to approximately 10 A in the vicinity of the helix. It suggests that bilayer phospholipids can adapt locally to strongly perturbing protein elements, causing the phospholipids to become a structural extension of the protein.

  4. A useful infrared source.

    PubMed

    Carlon, H R

    1966-08-01

    Reliable Inconel-sheathed cartridge heaters rated at hundreds or thousands of watts have been in use for many years. Miniature heaters have been manufactured, having axial leads, which when treated with an emissive coating meet or exceed Globar emissivities in the ir. Free-air temperatures approximating 800 degrees C have been obtained for power inputs of 10 W, while temperatures as high as 1150 degrees C are possible for short lifetimes, e.g., 10 h, at power dissipations of 24 W or more. Sources can be designed to operate from d or ac power with higher voltages and lower currents depending upon physical size limitations, resulting in simplified power supply problems. Although voltages from 12 V to 230 V are practical for larger units, the sources described below operated at 1060 degrees C from a nominal 1.07 A at 18.7 V d for apower consumption of 20 W variable continuously about this value. The small dimensions of these sources compare favorably to those of a 0.5-W electronic resistor. The present units are cylindrical, 1 cm long x 4 mm diam. The construction of smaller units is possible bt difficult under present state-of-the-art limitations. PMID:20057526

  5. A simple model for induction core voltage distributions

    SciTech Connect

    Briggs, Richard J.; Fawley, William M.

    2004-07-01

    In fall 2003 T. Hughes of MRC used a full EM simulation code (LSP) to show that the electric field stress distribution near the outer radius of the longitudinal gaps between the four Metglas induction cores is very nonuniform in the original design of the DARHT-2 accelerator cells. In this note we derive a simple model of the electric field distribution in the induction core region to provide physical insights into this result. The starting point in formulating our model is to recognize that the electromagnetic fields in the induction core region of the DARHT-2 accelerator cells should be accurately represented within a quasi-static approximation because the timescale for the fields to change is much longer than the EM wave propagation time. The difficulty one faces is the fact that the electric field is a mixture of both a ''quasi-magnetostatic field'' (having a nonzero curl, with Bdot the source) and a ''quasi-electrostatic field'' (the source being electric charges on the various metal surfaces). We first discuss the EM field structure on the ''micro-scale'' of individual tape windings in Section 2. The insights from that discussion are then used to formulate a ''macroscopic'' description of the fields inside an ''equivalent homogeneous tape wound core region'' in Section 3. This formulation explicitly separates the nonlinear core magnetics from the quasi-electrostatic components of the electric field. In Section 4 a physical interpretation of the radial dependence of the electrostatic component of the electric field derived from this model is presented in terms of distributed capacitances, and the voltage distribution from gap to gap is related to various ''equivalent'' lumped capacitances. Analytic solutions of several simple multi-core cases are presented in Sections 5 and 6 to help provide physical insight into the effect of various proposed changes in the geometrical parameters of the DARHT-2 accelerator cell. Our results show that over most of the gap

  6. Self-scanning of a dye laser due to feedback from a BaTiO/sub 3/ phase-conjugate reflector

    SciTech Connect

    Whitten, W.B.; Ramsey, J.M.

    1984-02-01

    Feedback from a self-pumped BaTiO/sub 3/ phase-conjugate reflector into an untuned cw dye laser produces substantial line narrowing (4--6 GHz) and generates a recurrent wavelength sweep from the rhodamine 6G peak at 618 nm to as far as 644 nm.

  7. Efficient circuit triggers high-current, high-voltage pulses

    NASA Technical Reports Server (NTRS)

    Green, E. D.

    1964-01-01

    Modified circuit uses diodes to effectively disconnect the charging resistors from the circuit during the discharge cycle. Result is an efficient parallel charging, high voltage pulse modulator with low voltage rating of components.

  8. Field effect transistors used as voltage controlled resistors

    NASA Technical Reports Server (NTRS)

    1964-01-01

    Two new methods of incorporating field effect transistors into circuit designs have resulted in linear response of this type transistor over a wide range of controlled voltage levels. This increases its usefulness as a voltage-controlled resistor.

  9. Design, conditioning, and performance of a high voltage, high brightness dc photoelectron gun with variable gap

    NASA Astrophysics Data System (ADS)

    Maxson, Jared; Bazarov, Ivan; Dunham, Bruce; Dobbins, John; Liu, Xianghong; Smolenski, Karl

    2014-09-01

    A new high voltage photoemission gun has been constructed at Cornell University which features a segmented insulator and a movable anode, allowing the cathode-anode gap to be adjusted. In this work, we describe the gun's overall mechanical and high voltage design, the surface preparation of components, as well as the clean construction methods. We present high voltage conditioning data using a 50 mm cathode-anode gap, in which the conditioning voltage exceeds 500 kV, as well as at smaller gaps. Finally, we present simulated emittance results obtained from a genetic optimization scheme using voltage values based on the conditioning data. These results indicate that for charges up to 100 pC, a 30 mm gap at 400 kV has equal or smaller 100% emittance than a 50 mm gap at 450 kV, and also a smaller core emittance, when placed as the source for the Cornell energy recovery linac photoinjector with bunch length constrained to be <3 ps rms. For 100 pC up to 0.5 nC charges, the 50 mm gap has larger core emittance than the 30 mm gap, but conversely smaller 100% emittance.

  10. Design, conditioning, and performance of a high voltage, high brightness dc photoelectron gun with variable gap

    SciTech Connect

    Maxson, Jared; Bazarov, Ivan; Dunham, Bruce; Dobbins, John; Liu, Xianghong; Smolenski, Karl

    2014-09-15

    A new high voltage photoemission gun has been constructed at Cornell University which features a segmented insulator and a movable anode, allowing the cathode-anode gap to be adjusted. In this work, we describe the gun's overall mechanical and high voltage design, the surface preparation of components, as well as the clean construction methods. We present high voltage conditioning data using a 50 mm cathode-anode gap, in which the conditioning voltage exceeds 500 kV, as well as at smaller gaps. Finally, we present simulated emittance results obtained from a genetic optimization scheme using voltage values based on the conditioning data. These results indicate that for charges up to 100 pC, a 30 mm gap at 400 kV has equal or smaller 100% emittance than a 50 mm gap at 450 kV, and also a smaller core emittance, when placed as the source for the Cornell energy recovery linac photoinjector with bunch length constrained to be <3 ps rms. For 100 pC up to 0.5 nC charges, the 50 mm gap has larger core emittance than the 30 mm gap, but conversely smaller 100% emittance.

  11. Compact ion accelerator source

    DOEpatents

    Schenkel, Thomas; Persaud, Arun; Kapadia, Rehan; Javey, Ali

    2014-04-29

    An ion source includes a conductive substrate, the substrate including a plurality of conductive nanostructures with free-standing tips formed on the substrate. A conductive catalytic coating is formed on the nanostructures and substrate for dissociation of a molecular species into an atomic species, the molecular species being brought in contact with the catalytic coating. A target electrode placed apart from the substrate, the target electrode being biased relative to the substrate with a first bias voltage to ionize the atomic species in proximity to the free-standing tips and attract the ionized atomic species from the substrate in the direction of the target electrode.

  12. 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.

  13. Complete low power controller for high voltage power systems

    SciTech Connect

    Sumner, R.; Blanar, G.

    1997-12-31

    The MHV100 is a custom CMOS integrated circuit, developed for the AMS experiment. It provides complete control for a single channel high voltage (HV) generator and integrates all the required digital communications, D to A and A to D converters, the analog feedback loop and output drivers. This chip has been designed for use in both distributed high voltage systems or for low cost single channel high voltage systems. The output voltage and current range is determined by the external components.

  14. Memristor-integrated voltage-stabilizing supercapacitor system.

    PubMed

    Liu, Bin; Liu, Boyang; Wang, Xianfu; Wu, Xinghui; Zhao, Wenning; Xu, Zhimou; Chen, Di; Shen, Guozhen

    2014-08-01

    Voltage-stabilized supercapacitors: A single supercapacitor formed with PCBM/Pt/IPS nanorod-array electrodes is designed and delivers enhanced areal capacitance, capacitance retention, and excellent electrical stability under bending, while a significant voltage-decrease is observed during the discharging process. Once integrated with the memristor, the memristor-integrated supercapacitor systems deliver an extremely low voltage-drop, indicating greatly enhanced voltage-stabilizing features.

  15. 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

  16. 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…

  17. Loop-voltage tomography in tokamaks using transient synchrotron radiation

    SciTech Connect

    Fisch, N.J.; Kritz, A.H. . Plasma Physics Lab.; Hunter Coll., New York, NY . Dept. of Physics)

    1989-07-01

    The loop voltage in tokamaks is particularly difficult to measure anywhere but at the plasma periphery. A brief, deliberate, perturbation of hot plasma electrons, however, produces a transient radiation response that is sensitive to this voltage. We investigate how such a radiation response can be used to diagnose the loop voltage. 24 refs., 6 figs.

  18. System for increasing corona inception voltage of insulating oils

    DOEpatents

    Rohwein, G.J.

    1998-05-19

    The Corona Inception Voltage of insulating oils is increased by repetitive cycles of prestressing the oil with a voltage greater than the corona inception voltage, and either simultaneously or serially removing byproducts of corona by evacuation and heating the oil. 5 figs.

  19. Neutron-induced single event burnout in high voltage electronics

    SciTech Connect

    Normand, E.; Wert, J.L.; Oberg, D.L.; Majewski, P.P.; Voss, P.; Wender, S.A.

    1997-12-01

    Energetic neutrons with an atmospheric neutron spectrum, which were demonstrated to induce single event burnout in power MOSFETs, have been shown to induce burnout in high voltage (>3,000V) electronics when operated at voltages as low as 50% of rated voltage. The laboratory failure rates correlate well with field failure rates measured in Europe.

  20. 30 CFR 75.813 - High-voltage longwalls; scope.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false High-voltage longwalls; scope. 75.813 Section 75.813 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution High-Voltage Longwalls § 75.813...

  1. 30 CFR 75.804 - Underground high-voltage cables.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Underground high-voltage cables. 75.804 Section 75.804 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution § 75.804 Underground high-voltage cables....

  2. 30 CFR 75.826 - High-voltage trailing cables.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false High-voltage trailing cables. 75.826 Section 75.826 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution High-Voltage Longwalls § 75.826...

  3. Molecular mechanism of voltage sensing in voltage-gated proton channels.

    PubMed

    Gonzalez, Carlos; Rebolledo, Santiago; Perez, Marta E; Larsson, H Peter

    2013-03-01

    Voltage-gated proton (Hv) channels play an essential role in phagocytic cells by generating a hyperpolarizing proton current that electrically compensates for the depolarizing current generated by the NADPH oxidase during the respiratory burst, thereby ensuring a sustained production of reactive oxygen species by the NADPH oxidase in phagocytes to neutralize engulfed bacteria. Despite the importance of the voltage-dependent Hv current, it is at present unclear which residues in Hv channels are responsible for the voltage activation. Here we show that individual neutralizations of three charged residues in the fourth transmembrane domain, S4, all reduce the voltage dependence of activation. In addition, we show that the middle S4 charged residue moves from a position accessible from the cytosolic solution to a position accessible from the extracellular solution, suggesting that this residue moves across most of the membrane electric field during voltage activation of Hv channels. Our results show for the first time that the charge movement of these three S4 charges accounts for almost all of the measured gating charge in Hv channels. PMID:23401575

  4. 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

  5. Improved Control of Charging Voltage for Li-Ion Battery

    NASA Technical Reports Server (NTRS)

    Timmerman, Paul; Bugga, Ratnakumar

    2006-01-01

    The protocol for charging a lithium-ion battery would be modified, according to a proposal, to compensate for the internal voltage drop (charging current internal resistance of the battery). The essence of the modification is to provide for measurement of the internal voltage drop and to increase the terminal-voltage setting by the amount of the internal voltage drop. Ordinarily, a lithium-ion battery is charged at constant current until its terminal voltage attains a set value equal to the nominal full-charge potential. The set value is chosen carefully so as not to exceed the lithium-plating potential, because plated lithium in metallic form constitutes a hazard. When the battery is charged at low temperature, the internal voltage drop is considerable because the electrical conductivity of the battery electrolyte is low at low temperature. Charging the battery at high current at any temperature also gives rise to a high internal voltage drop. In some cases, the internal voltage drop can be as high as 1 volt per cell. Because the voltage available for charging is less than the terminal voltage by the amount of the internal voltage drop, the battery is not fully charged (see figure), even when the terminal voltage reaches the set value. In the modified protocol, the charging current would be periodically interrupted so that the zero-current battery-terminal voltage indicative of the state of charge could be measured. The terminal voltage would also be measured at full charging current. The difference between the full-current and zero-current voltages would equal the internal voltage drop. The set value of terminal voltage would then be increased beyond the nominal full-charge potential by the amount of the internal voltage drop. This adjustment would be performed repeatedly, in real time, so that the voltage setting would track variations in the internal voltage drop to afford full charge without risk of lithium plating. If the charging current and voltage settings

  6. Digital-circuit analysis of short-gate tunnel FETs for low-voltage applications

    NASA Astrophysics Data System (ADS)

    Zhuge, Jing; Verhulst, Anne S.; Vandenberghe, William G.; Dehaene, Wim; Huang, Ru; Wang, Yangyuan; Groeseneken, Guido

    2011-08-01

    This paper investigates the potential of tunnel field-effect transistors (TFETs), with emphasis on short-gate TFETs, by simulation for low-power digital applications having a supply voltage lower than 0.5 V. A transient study shows that the tunneling current has a negligible contribution in charging and discharging the gate capacitance of TFETs. In spite of a higher resistance region in the short-gate TFET, the gate (dis)charging speed still meets low-voltage application requirements. A circuit analysis is performed on short-gate TFETs with different materials, such as Si, Ge and heterostructures in terms of voltage overshoot, delay, static power, energy consumption and energy delay product (EDP). These results are compared to MOSFET and full-gate TFET performance. It is concluded that short-gate heterostructure TFETs (Ge-source for nTFET, In0.6Ga0.4As-source for pTFET) are promising candidates to extend the supply voltage to lower than 0.5 V because they combine the advantage of a low Miller capacitance, due to the short-gate structures, and strong drive current in TFETs, due to the narrow bandgap material in the source. At a supply voltage of 0.4 V and for an EOT and channel length of 0.6 nm and 40 nm, respectively, a three-stage inverter chain based on short-gate heterostructure TFETs saves 40% energy consumption per cycle at the same delay and shows 60%-75% improvement of EDP at the same static power, compared to its full-gate counterpart. When compared to the MOSFET, better EDP can be achieved in the heterostructure TFET especially at low static power consumption.

  7. Controllable Threshold Voltage in Organic Complementary Logic Circuits with an Electron-Trapping Polymer and Photoactive Gate Dielectric Layer.

    PubMed

    Dao, Toan Thanh; Sakai, Heisuke; Nguyen, Hai Thanh; Ohkubo, Kei; Fukuzumi, Shunichi; Murata, Hideyuki

    2016-07-20

    We present controllable and reliable complementary organic transistor circuits on a PET substrate using a photoactive dielectric layer of 6-[4'-(N,N-diphenylamino)phenyl]-3-ethoxycarbonylcoumarin (DPA-CM) doped into poly(methyl methacrylate) (PMMA) and an electron-trapping layer of poly(perfluoroalkenyl vinyl ether) (Cytop). Cu was used for a source/drain electrode in both the p-channel and n-channel transistors. The threshold voltage of the transistors and the inverting voltage of the circuits were reversibly controlled over a wide range under a program voltage of less than 10 V and under UV light irradiation. At a program voltage of -2 V, the inverting voltage of the circuits was tuned to be at nearly half of the supply voltage of the circuit. Consequently, an excellent balance between the high and low noise margins (NM) was produced (64% of NMH and 68% of NML), resulting in maximum noise immunity. Furthermore, the programmed circuits showed high stability, such as a retention time of over 10(5) s for the inverter switching voltage. Our findings bring about a flexible, simple way to obtain robust, high-performance organic circuits using a controllable complementary transistor inverter. PMID:27348479

  8. Breakdown voltage reliability improvement in gas-discharge tube surge protectors employing graphite field emitters

    NASA Astrophysics Data System (ADS)

    Žumer, Marko; Zajec, Bojan; Rozman, Robert; Nemanič, Vincenc

    2012-04-01

    Gas-discharge tube (GDT) surge protectors are known for many decades as passive units used in low-voltage telecom networks for protection of electrical components from transient over-voltages (discharging) such as lightning. Unreliability of the mean turn-on DC breakdown voltage and the run-to-run variability has been overcome successfully in the past by adding, for example, a radioactive source inside the tube. Radioisotopes provide a constant low level of free electrons, which trigger the breakdown. In the last decades, any concept using environmentally harmful compounds is not acceptable anymore and new solutions were searched. In our application, a cold field electron emitter source is used as the trigger for the gas discharge but with no activating compound on the two main electrodes. The patent literature describes in details the implementation of the so-called trigger wires (auxiliary electrodes) made of graphite, placed in between the two main electrodes, but no physical explanation has been given yet. We present experimental results, which show that stable cold field electron emission current in the high vacuum range originating from the nano-structured edge of the graphite layer is well correlated to the stable breakdown voltage of the GDT surge protector filled with a mixture of clean gases.

  9. An Unusual Source of Multiple ESD Events in Electronic Equipment

    NASA Astrophysics Data System (ADS)

    Smith, D. C.

    2015-10-01

    Small wall mounted power supplies that plug directly into AC power mains and furnish power, usually low voltage DC, to equipment over a low voltage cable are ubiquitous in the electronic field. It is shown that these low voltage supplies can be the source of multiple ESD events that are fed to the connected system on the low voltage cable when an ESD event is applied to the system or directly to the power supplies. The multiple ESD events produce nasty current waveforms Examples of these waveforms and the measurement method are given. The results have been duplicated in three laboratories, results are presented from two of the three.

  10. A vesicle-trafficking protein commandeers Kv channel voltage sensors for voltage-dependent secretion.

    PubMed

    Grefen, Christopher; Karnik, Rucha; Larson, Emily; Lefoulon, Cécile; Wang, Yizhou; Waghmare, Sakharam; Zhang, Ben; Hills, Adrian; Blatt, Michael R

    2015-01-01

    Growth in plants depends on ion transport for osmotic solute uptake and secretory membrane trafficking to deliver material for wall remodelling and cell expansion. The coordination of these processes lies at the heart of the question, unresolved for more than a century, of how plants regulate cell volume and turgor. Here we report that the SNARE protein SYP121 (SYR1/PEN1), which mediates vesicle fusion at the Arabidopsis plasma membrane, binds the voltage sensor domains (VSDs) of K(+) channels to confer a voltage dependence on secretory traffic in parallel with K(+) uptake. VSD binding enhances secretion in vivo subject to voltage, and mutations affecting VSD conformation alter binding and secretion in parallel with channel gating, net K(+) concentration, osmotic content and growth. These results demonstrate a new and unexpected mechanism for secretory control, in which a subset of plant SNAREs commandeer K(+) channel VSDs to coordinate membrane trafficking with K(+) uptake for growth.

  11. 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.

  12. 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.

  13. Connecting Renewables Directly to the Grid: Resilient Multi-Terminal HVDC Networks with High-Voltage High-Frequency Electronics

    SciTech Connect

    2012-01-23

    GENI Project: GE is developing electricity transmission hardware that could connect distributed renewable energy sources, like wind farms, directly to the grid—eliminating the need to feed the energy generated through intermediate power conversion stations before they enter the grid. GE is using the advanced semiconductor material silicon carbide (SiC) to conduct electricity through its transmission hardware because SiC can operate at higher voltage levels than semiconductors made out of other materials. This high-voltage capability is important because electricity must be converted to high-voltage levels before it can be sent along the grid’s network of transmission lines. Power companies do this because less electricity is lost along the lines when the voltage is high.

  14. Effects of electrical voltage/current on farm animals: How to detect and remedy problems. Agriculture handbook

    SciTech Connect

    Lefcourt, A.M.

    1991-12-01

    The handbook examines (1) the history of stray voltage/current problems on farms, (2) the physical and electrical sources of stray voltage/current phenomena, (3) the physiological and behavioral bases for losses in milk production, (4) methods for identifying and detecting stray voltage/current problems, (5) methods for mitigating such problems, and (6) areas where further research may be warranted. While the primary emphasis is on cattle and dairy farms, the theories and procedures discussed are completely relevant to all types of livestock and livestock housing facilities. Recommendations are made for action levels and concerning mitigation techniques. The fundamental conclusion of the handbook is that stray voltages/currents can be reduced to acceptable levels.

  15. Voltage clamp experiments on ventricular myocardial fibres

    PubMed Central

    Beeler, G. W.; Reuter, H.

    1970-01-01

    1. A voltage clamp method utilizing a sucrose gap and glass microelectrodes was developed and used to study dog ventricular myocardial fibre bundles. The limitations and the reliability of this method are demonstrated by a series of tests. 2. A dynamic sodium current, excited at membrane potentials more positive than -65 mV, was measured. The equilibrium potential for this large, rapid inward current depends directly on [Na]o, shifting 29·0 ± 2·3 mV (± S.E. of mean), as opposed to a theoretically expected value of 30·6 mV, when [Na]o is reduced to 31% of normal. 3. Sodium current is inactivated by conditioning depolarizations. Complete inactivation occurs with conditioning potentials more positive than -45 mV, and 50% inactivation occurs at about -55 mV. The location of the inactivation curve shifts along the voltage axis, when [Ca]o is varied between 0·2 and 7·2 mM. 4. A second, much smaller and slower net inward current, with a threshold around -30 mV, and an equilibrium potential above +40 mV was also observed. 5. The `steady-state' current—voltage relationship (after 300-600 msec) exhibits inward-going (anomalous) rectification with negative slope between -50 and -25 mV. 6. A small, very slowly developing component of outward current was observed at inside positive potentials. The equilibrium potential for this current, although slightly dependent on [K]o, is neither identical with the potassium equilibrium potential nor with the resting potential in normal Tyrode solution. 7. Anatomical limitations, primarily resistance in the extracellular space within the bundle, prevent complete characterization of the rapid, large sodium current, but do not limit the application of the clamp method to the study of other, smaller and slower currents. The evidence for this is discussed extensively in the Appendix. PMID:5503866

  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. Surface interactions and high-voltage current collection

    NASA Technical Reports Server (NTRS)

    Mandell, M. J.; Katz, I.

    1985-01-01

    Spacecraft of the future will be larger and have higher power requirements than any flown to date. For several reasons, it is desirable to operate a high power system at high voltage. While the optimal voltages for many future missions are in the range 500 to 5000 volts, the highest voltage yet flown is approximately 100 volts. The NASCAP/LEO code is being developed to embody the phenomenology needed to model the environmental interactions of high voltage spacecraft. Some plasma environment are discussed. The treatment of the surface conductivity associated with emitted electrons and some simulations by NASCAP/LEO of ground based high voltage interaction experiments are described.

  18. 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.

  19. High-Voltage, Asymmetric-Waveform Generator

    NASA Technical Reports Server (NTRS)

    Beegle, Luther W.; Duong, Tuan A.; Duong, Vu A.; Kanik, Isik

    2008-01-01

    The shapes of waveforms generated by commercially available analytical separation devices, such as some types of mass spectrometers and differential mobility spectrometers are, in general, inadequate and result in resolution degradation in output spectra. A waveform generator was designed that would be able to circumvent these shortcomings. It is capable of generating an asymmetric waveform, having a peak amplitude as large as 2 kV and frequency of several megahertz, which can be applied to a capacitive load. In the original intended application, the capacitive load would consist of the drift plates in a differential-mobility spectrometer. The main advantage to be gained by developing the proposed generator is that the shape of the waveform is made nearly optimum for various analytical devices requiring asymmetric-waveform such as differential-mobility spectrometers. In addition, this waveform generator could easily be adjusted to modify the waveform in accordance with changed operational requirements for differential-mobility spectrometers. The capacitive nature of the load is an important consideration in the design of the proposed waveform generator. For example, the design provision for shaping the output waveform is based partly on the principle that (1) the potential (V) on a capacitor is given by V=q/C, where C is the capacitance and q is the charge stored in the capacitor; and, hence (2) the rate of increase or decrease of the potential is similarly proportional to the charging or discharging current. The proposed waveform generator would comprise four functional blocks: a sine-wave generator, a buffer, a voltage shifter, and a high-voltage switch (see Figure 1). The sine-wave generator would include a pair of operational amplifiers in a feedback configuration, the parameters of which would be chosen to obtain a sinusoidal timing signal of the desired frequency. The buffer would introduce a slight delay (approximately equal to 20 ns) but would otherwise

  20. Visualizing voltage dynamics in zebrafish heart.

    PubMed

    Tsutsui, Hidekazu; Higashijima, Shin-ichi; Miyawaki, Atsushi; Okamura, Yasushi

    2010-06-15

    The zebrafish heart provides a useful vertebrate cardiovascular model with outstanding advantages, including genetic manipulatability, optical accessibility and rapid development. In addition, an emerging topic in cardiotoxicity assay and drug discovery is its use in phenotype-based chemical screening. Here, we report a technique that allows non-invasive voltage mapping in beating heart using a genetically encoded probe for transmembrane potential. Application of the anti-allergy compound astemizole resulted in aberrant propagation of excitation, which accounted for a lack of ventricular contraction. This optical method will provide new opportunities in broad areas of physiological, developmental and pharmacological cardiovascular research. PMID:20421282