WorldWideScience

Sample records for voltage long-life gas

  1. Long life gas laser system and method

    International Nuclear Information System (INIS)

    Hochuli, E.E.

    1975-01-01

    A long life gas discharge laser having an improved self-repairing cathode system is described. In a specific embodiment, water vapor having a partial pressure below about 10 -5 torr incorporated in a molecular sieve is used to provide impurities (in this case water vapor) for repairing the cathode surface by regenerating the oxide surface and/or preventing same from deteriorating. Other impurities may be incorporated in the molecular sieve such as hydrogen, oxygen, for example. In some cases CO 2 may be used. This application includes material disclosed in a paper entitled ''Continuation of the Investigation into Material Properties Affecting the Frequency Stability and Reliability of He-Ne Laser Structures'' submitted to the Office of Naval Research dated June 1972 by the inventor hereof and also a paper entitled ''Investigations of the Long Term Frequency Stability of Stable Laser Structures'' Progress Report for ONR Contract N00014-67-A-D239-0016 July 1972 by the inventor hereof. A royalty free license is hereby granted to the United States for use of the invention for all government purposes. (auth)

  2. Calibration on Pegase of a selective D.R.G. installation for short life and long life fission gas

    International Nuclear Information System (INIS)

    Vasnier, F.

    1968-01-01

    Pegase irradiation loops are equipped with a detection installation which measures the global activity of short-life and long-life fission gases which are released in CO 2 , but the reduced size of circuits in the loop results in an accumulation of long life fission gases, and therefore in problems in the interpretation of measured signals. Thus, the authors propose an additional detection installation which allows long-life fission gases to be separately measured. The principle is to ensure a partial decay of the sampled gas by imposing an additional transit time in order to get rid of short-life fission gases which have a radioactive period of some tenths of a second. A second detector is then used to measure the residual activity of long-life fission gases. The author describes the installation (the normal circuit and the modified circuit), reports the performed tests and the calibration, presents and discusses the obtained results and the installation sensitivity (for short-life and long-life fission gases), and reports their application to the relationship between DRG (sheath failure detection) signals obtained on Pegase and on EDF and EL4 reactors

  3. Design Study of Modular Nuclear Power Plant with Small Long Life Gas Cooled Fast Reactors Utilizing MOX Fuel

    Science.gov (United States)

    Ilham, Muhammad; Su'ud, Zaki

    2017-01-01

    Growing energy needed due to increasing of the world’s population encourages development of technology and science of nuclear power plant in its safety and security. In this research, it will be explained about design study of modular fast reactor with helium gas cooling (GCFR) small long life reactor, which can be operated over 20 years. It had been conducted about neutronic design GCFR with Mixed Oxide (UO2-PuO2) fuel in range of 100-200 MWth NPPs of power and 50-60% of fuel fraction variation with cylindrical pin cell and cylindrical balance of reactor core geometry. Calculation method used SRAC-CITATION code. The obtained results are the effective multiplication factor and density value of core reactor power (with geometry optimalization) to obtain optimum design core reactor power, whereas the obtained of optimum core reactor power is 200 MWth with 55% of fuel fraction and 9-13% of percentages.

  4. Conceptual design study on very small long-life gas cooled fast reactor using metallic natural Uranium-Zr as fuel cycle input

    International Nuclear Information System (INIS)

    Monado, F.; Permana, S.

    2013-01-01

    Full-text: A conceptual design study of very small 350 MWth Gas-cooled Fast Reactors with Helium coolant has been performed. In this study Modified CANDLE burn-up scheme was implemented to create small and long life fast reactors with natural Uranium as fuel cycle input. Such system can utilize natural Uranium resources efficiently without the necessity of enrichment plant or reprocessing plant. The core with metallic fuel based was subdivided into 10 regions with the same volume. The fresh Natural Uranium is initially put in region-1, after one cycle of 10 years of burn-up it is shifted to region-2 and the each region-1 is filled by fresh Natural Uranium fuel. This concept is basically applied to all axial regions. The reactor discharge burn-up is 31.8 % HM. From the neutronic point of view, this design is in compliance with good performance. (author)

  5. Conceptual design study on very small long-life gas cooled fast reactor using metallic natural Uranium-Zr as fuel cycle input

    International Nuclear Information System (INIS)

    Monado, Fiber; Ariani, Menik; Su'ud, Zaki; Waris, Abdul; Basar, Khairul; Permana, Sidik; Aziz, Ferhat; Sekimoto, Hiroshi

    2014-01-01

    A conceptual design study of very small 350 MWth Gas-cooled Fast Reactors with Helium coolant has been performed. In this study Modified CANDLE burn-up scheme was implemented to create small and long life fast reactors with natural Uranium as fuel cycle input. Such system can utilize natural Uranium resources efficiently without the necessity of enrichment plant or reprocessing plant. The core with metallic fuel based was subdivided into 10 regions with the same volume. The fresh Natural Uranium is initially put in region-1, after one cycle of 10 years of burn-up it is shifted to region-2 and the each region-1 is filled by fresh Natural Uranium fuel. This concept is basically applied to all axial regions. The reactor discharge burn-up is 31.8% HM. From the neutronic point of view, this design is in compliance with good performance

  6. The study of capability natural uranium as fuel cycle input for long life gas cooled fast reactors with helium as coolant

    Energy Technology Data Exchange (ETDEWEB)

    Ariani, Menik, E-mail: menikariani@gmail.com; Satya, Octavianus Cakra; Monado, Fiber [Department of Physics, Faculty of Mathematics and Natural Sciences, Sriwijaya University, jl Palembang-Prabumulih km 32 Indralaya OganIlir, South of Sumatera (Indonesia); Su’ud, Zaki [Nuclear and Biophysics Research Division, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, jlGanesha 10, Bandung (Indonesia); Sekimoto, Hiroshi [CRINES, Tokyo Institute of Technology, 2-12-11N1-17 Ookayama, Meguro-Ku, Tokyo (Japan)

    2016-03-11

    The objective of the present research is to assess the feasibility design of small long-life Gas Cooled Fast Reactor with helium as coolant. GCFR included in the Generation-IV reactor systems are being developed to provide sustainable energy resources that meet future energy demand in a reliable, safe, and proliferation-resistant manner. This reactor can be operated without enrichment and reprocessing forever, once it starts. To obtain the capability of consuming natural uranium as fuel cycle input modified CANDLE burn-up scheme was adopted in this system with different core design. This study has compared the core with three designs of core reactors with the same thermal power 600 MWth. The fuel composition each design was arranged by divided core into several parts of equal volume axially i.e. 6, 8 and 10 parts related to material burn-up history. The fresh natural uranium is initially put in region 1, after one cycle of 10 years of burn-up it is shifted to region 2 and the region 1 is filled by fresh natural uranium fuel. This concept is basically applied to all regions, i.e. shifted the core of the region (i) into region (i+1) region after the end of 10 years burn-up cycle. The calculation results shows that for the burn-up strategy on “Region-8” and “Region-10” core designs, after the reactors start-up the operation furthermore they only needs natural uranium supply to the next life operation until one period of refueling (10 years).

  7. New perspectives in vacuum high voltage insulation. II. Gas desorption

    CERN Document Server

    Diamond, W T

    1998-01-01

    An examination has been made of gas desorption from unbaked electrodes of copper, niobium, aluminum, and titanium subjected to high voltage in vacuum. It has been shown that the gas is composed of water vapor, carbon monoxide, and carbon dioxide, the usual components of vacuum outgassing, plus an increased yield of hydrogen and light hydrocarbons. The gas desorption was driven by anode conditioning as the voltage was increased between the electrodes. The gas is often desorbed as microdischarges-pulses of a few to hundreds of microseconds-and less frequently in a more continuous manner without the obvious pulsed structure characteristic of microdischarge activity. The quantity of gas released was equivalent to many monolayers and consisted mostly of neutral molecules with an ionic component of a few percent. A very significant observation was that the gas desorption was more dependent on the total voltage between the electrodes than on the electric field. It was not triggered by field-emitted electrons but oft...

  8. Uv laser triggering of high-voltage gas switches

    International Nuclear Information System (INIS)

    Woodworth, J.R.; Frost, C.A.; Green, T.A.

    1982-01-01

    Two different techniques are discussed for uv laser triggering of high-voltage gas switches using a KrF laser (248 nm) to create an ionized channel through the dielectric gas in a spark gap. One technique uses an uv laser to induce breakdown in SF 6 . For this technique, we present data that demonstrate a 1-sigma jitter of +- 150 ps for a 0.5-MV switch at 80% of its self-breakdown voltage using a low-divergence KrF laser. The other scheme uses additives to the normal dielectric gas, such as tripropylamine, which are selected to undergo resonant two-step ionization in the uv laser field

  9. Gas tube-switched high voltage DC power converter

    Science.gov (United States)

    She, Xu; Bray, James William; Sommerer, Timothy John; Chokhawala, Rahul

    2018-05-15

    A direct current (DC)-DC converter includes a transformer and a gas tube-switched inverter circuit. The transformer includes a primary winding and a secondary winding. The gas tube-switched inverter circuit includes first and second inverter load terminals and first and second inverter input terminals. The first and second inverter load terminals are coupled to the primary winding. The first and second inverter input terminals are couplable to a DC node. The gas tube-switched inverter circuit further includes a plurality of gas tube switches respectively coupled between the first and second inverter load terminals and the first and second inverter input terminals. The plurality of gas tube switches is configured to operate to generate an alternating current (AC) voltage at the primary winding.

  10. Statistical characteristics of transient enclosure voltage in ultra-high-voltage gas-insulated switchgear

    Science.gov (United States)

    Cai, Yuanji; Guan, Yonggang; Liu, Weidong

    2017-06-01

    Transient enclosure voltage (TEV), which is a phenomenon induced by the inner dielectric breakdown of SF6 during disconnector operations in a gas-insulated switchgear (GIS), may cause issues relating to shock hazard and electromagnetic interference to secondary equipment. This is a critical factor regarding the electromagnetic compatibility of ultra-high-voltage (UHV) substations. In this paper, the statistical characteristics of TEV at UHV level are collected from field experiments, and are analyzed and compared to those from a repeated strike process. The TEV waveforms during disconnector operations are recorded by a self-developed measurement system first. Then, statistical characteristics, such as the pulse number, duration of pulses, frequency components, magnitude and single pulse duration, are extracted. The transmission line theory is introduced to analyze the TEV and is validated by the experimental results. Finally, the relationship between the TEV and the repeated strike process is analyzed. This proves that the pulse voltage of the TEV is proportional to the corresponding breakdown voltage. The results contribute to the definition of the standard testing waveform of the TEV, and can aid the protection of electronic devices in substations by minimizing the threat of this phenomenon.

  11. Method and system for a gas tube switch-based voltage source high voltage direct current transmission system

    Science.gov (United States)

    She, Xu; Chokhawala, Rahul Shantilal; Zhou, Rui; Zhang, Di; Sommerer, Timothy John; Bray, James William

    2016-12-13

    A voltage source converter based high-voltage direct-current (HVDC) transmission system includes a voltage source converter (VSC)-based power converter channel. The VSC-based power converter channel includes an AC-DC converter and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and a DC-AC inverter include at least one gas tube switching device coupled in electrical anti-parallel with a respective gas tube diode. The VSC-based power converter channel includes a commutating circuit communicatively coupled to one or more of the at least one gas tube switching devices. The commutating circuit is configured to "switch on" a respective one of the one or more gas tube switching devices during a first portion of an operational cycle and "switch off" the respective one of the one or more gas tube switching devices during a second portion of the operational cycle.

  12. LMFBR Ultra Long Life Cores

    International Nuclear Information System (INIS)

    Schmidt, J.E.; Doncals, R.A.; Porter, C.A.; Gundy, L.M.

    1986-01-01

    The Ultra Long Life Core is an attractive and innovative design approach with several extremely beneficial attributes. Long Life cores are applicable to the full range of LMR plant sizes resulting in lifetimes up to 30 years. Core life is somewhat limited for smaller plant sizes, however significant benefits of this approach still exist for all plant sizes. The union of long life cores and the complementary inherent safety technology offer a means of utilizing the well-proven oxide fuel in a system with unsurpassed safety capability. A further benefit is that the uranium fuel cycle can be used in long life cores, especially for initial LMR plant deployment, thereby eliminating the need for reprocessing prior to starting LMR plant construction in the U.S. Finally the long life core significantly reduces power costs. With inherent safety capability designed into an LMR and with the ULLC fuel cycle, power costs competitive with light water plants are achievable while offering improved operational flexibility derived through extending refueling intervals

  13. Low-profile high-voltage compact gas switch

    International Nuclear Information System (INIS)

    Goerz, D.A.; Wilson, M.J.; Speer, R.D.

    1997-01-01

    This paper discusses the development and testing of a low-profile, high-voltage, spark-gap switch designed to be closely coupled with other components into an integrated high-energy pulsed-power source. The switch is designed to operate at 100 kV using SF6 gas pressurized to less than 0.7 MPa. The volume of the switch cavity region is less than 1.5 cm3, and the field stress along the gas-dielectric interface is as high as 130 kV/cm. The dielectric switch body has a low profile that is only I -cm tall at its greatest extent and nominally 2-mm thick over most of its area. This design achieves a very low inductance of less than 5 nH, but results in field stresses exceeding 500 kV/cm in the dielectric material. Field modeling was done to determine the appropriate shape for the highly stressed insulator and electrodes, and special manufacturing techniques were employed to mitigate the usual mechanisms that induce breakdown and failure in solid dielectrics. Static breakdown tests verified that the switch operates satisfactorily at 100 kV levels. The unit has been characterized with different shaped electrodes having nominal gap spacings of 2.0, 2.5, and 3.0 mm. The relationship between self-break voltage and operating pressure agrees well with published data on gas properties, accounting for the field enhancements of the electrode shapes being used. Capacitor discharge tests in a low inductance test fixture exhibited peak currents up to 25 kA with characteristic frequencies of the ringdown circuit ranging from 10 to 20 MHz. The ringdown waveforms and scaling of measured parameters agree well with circuit modeling of the switch and test fixture. Repetitive operation has been demonstrated at moderate rep-rates up to 15 Hz, limited by the power supply being used. Preliminary tests to evaluate lifetime of the compact switch assembly have been encouraging. In one case, after more than 7,000 high-current ringdown tests with approximately 30 C of total charge transferred, the

  14. Design considerations and data for gas-insulated high voltage structures

    International Nuclear Information System (INIS)

    Hopkins, D.B.

    1975-11-01

    This paper is intended to benefit the person faced with the occasional task of designing gas insulated high-voltage structures or spark gaps and who must decide upon the proper geometry, spacings, gas type, and pressure for reliable voltage-holding. An approach is presented along with a summary of how various factors affect voltage breakdown. The design procedures described apply to situations where the influence of nearby insulators is negligible. The accuracy of the data is estimated to be within 10 to 15 percent, a value usually attained in practice only when one follows the cautionary advice discussed in the paragraphs on materials preparation, gas properties, and conditioning

  15. Gas stream analysis using voltage-current time differential operation of electrochemical sensors

    Science.gov (United States)

    Woo, Leta Yar-Li; Glass, Robert Scott; Fitzpatrick, Joseph Jay; Wang, Gangqiang; Henderson, Brett Tamatea; Lourdhusamy, Anthoniraj; Steppan, James John; Allmendinger, Klaus Karl

    2018-01-02

    A method for analysis of a gas stream. The method includes identifying an affected region of an affected waveform signal corresponding to at least one characteristic of the gas stream. The method also includes calculating a voltage-current time differential between the affected region of the affected waveform signal and a corresponding region of an original waveform signal. The affected region and the corresponding region of the waveform signals have a sensitivity specific to the at least one characteristic of the gas stream. The method also includes generating a value for the at least one characteristic of the gas stream based on the calculated voltage-current time differential.

  16. Prediction of picosecond voltage collapse and electromagnetic wave generation in gas avalanche switches

    International Nuclear Information System (INIS)

    Mayhall, D.J.; Yee, J.H.; Duong-Van, M.; Villa, F.

    1988-01-01

    A picosecond speed switch, the Gas Avalanche Switch (GAS), has been proposed for GeV linear accelerators. The medium is gas at high pressure (100 - 700 atm). An avalanche discharge is induced between pulse-charged high voltage electrodes by electron deposition from a fast laser pulse. Avalanche electrons move to the positive electrode, causing the applied voltage to collapse in picoseconds. A two-dimensional (2D) electromagnetic electron fluid computer code calculates the avalanche evolution and voltage collapse in air for an infinite parallel plate capacitor with a 0.1 mm spacing. Calculations are done for an accelerator switch geometry consisting of a 0.7 mm wide by 0.8 mm high, rectangular, high voltage center electrode (CE) between the grounded plates of a parallel plate line of 2 mm spacing. Several variations of CE elevation and initial electron deposition are investigated The 2D character of the outgoing TEM waves is shown

  17. Current-Voltage Characteristics of DC Discharge in Micro Gas Jet Injected into Vacuum Environment

    International Nuclear Information System (INIS)

    Matra, K; Furuta, H; Hatta, A

    2013-01-01

    A current-voltage characteristic of direct current (DC) gas discharge operated in a micro gas jet injected into a secondary electron microscope (SEM) chamber is presented. Ar gas was injected through a 30 μm orifice gas nozzle (OGN) and was evacuated by an additional pump to keep the high vacuum environment. Gas discharges were ignited between the OGN as anode and a counter electrode of Si wafer. The discharge was self-pulsating in most of the cases while it was stable at lower pressure, larger gap length, and larger time averaged current. The self-pulsating discharge was oscillated by the RC circuit consisting of a stray capacitor and a large ballast resistor. The real time plots of voltage and current during the pulsating was investigated using a discharge model.

  18. Breakdown voltage reduction by field emission in multi-walled carbon nanotubes based ionization gas sensor

    Energy Technology Data Exchange (ETDEWEB)

    Saheed, M. Shuaib M.; Muti Mohamed, Norani; Arif Burhanudin, Zainal, E-mail: zainabh@petronas.com.my [Centre of Innovative Nanostructures and Nanodevices, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia)

    2014-03-24

    Ionization gas sensors using vertically aligned multi-wall carbon nanotubes (MWCNT) are demonstrated. The sharp tips of the nanotubes generate large non-uniform electric fields at relatively low applied voltage. The enhancement of the electric field results in field emission of electrons that dominates the breakdown mechanism in gas sensor with gap spacing below 14 μm. More than 90% reduction in breakdown voltage is observed for sensors with MWCNT and 7 μm gap spacing. Transition of breakdown mechanism, dominated by avalanche electrons to field emission electrons, as decreasing gap spacing is also observed and discussed.

  19. (PO_4)"3"− polyanions doped LiNi_1_/_3Co_1_/_3Mn_1_/_3O_2: An ultrafast-rate, long-life and high-voltage cathode material for Li-ion rechargeable batteries

    International Nuclear Information System (INIS)

    Cong, Lina; Zhao, Qin; Wang, Zhao; Zhang, Yuhang; Wu, Xinglong; Zhang, Jingping; Wang, Rongshun; Xie, Haiming; Sun, Liqun

    2016-01-01

    Highlights: • LiNi_1_/_3Co_1_/_3Mn_1_/_3O_2 layered structure is doped with (PO_4)"3"− polyanions. • Results confirm that (PO_4)"3"− influences MO_6 octahedral environment in LiNi_1_/_3Co_1_/_3Mn_1_/_3O_2 lattice. • Charge–discharge properties are investigated under high voltage battery operation. • Cycling and rate performance of the doped materials is markedly enhanced. • Pre-cycling treatment inhibits microcracks at the grain boundaries at 4.7–2.8 V. - Abstract: Layered compounds LiNi_1_/_3Co_1_/_3Mn_1_/_3O_2 have recently received much attention as they have been regarded as a promising cathode materials for industrial application. However, its fast energy density decay and poor rate performance which originate from structure disruption especially at high rate and high cut-off voltage limit its large-scale application. Here, a novel designed concept and facile method were firstly used to fabricate (PO_4)"3"− polyanions doped layered LiNi_1_/_3Co_1_/_3Mn_1_/_3O_2 (LNMC-(PO_4) _0_._0_1_5-O_1_._9_4) structure, which could offer more stable high-voltage cycling performance and high rate capability. We attribute this improved performance to the robust P_t_e_t-O covalence, which will stabilize the oxygen close-packed structure during repeated cycling. Moreover, our stepwise pre-cycling treatments could effectively restrain the formation of micro-cracks and non-crystallization defects, and significantly improve cyclic durability with high charge voltage of 4.7V. The LNMC-(PO_4) _0_._0_1_5-O_1_._9_4 electrode can still delivers capacity retention of 81% after 200 cycles at a current density of 300mA g"−"1. The preliminary results reported here manifest that this novel-designed LNMC-(PO_4) _0_._0_1_5-O_1_._9_4 material represents an attractive alternative to ultrafast-rate, long-life and high-voltage electrode material for lithium ion batteries.

  20. Piezoelectric transformers for low-voltage generation of gas discharges and ionic winds in atmospheric air

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Michael J. [Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indianapolis 46556 (United States); Go, David B., E-mail: dgo@nd.edu [Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indianapolis 46556 (United States); Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indianapolis 46556 (United States)

    2015-12-28

    To generate a gas discharge (plasma) in atmospheric air requires an electric field that exceeds the breakdown threshold of ∼30 kV/cm. Because of safety, size, or cost constraints, the large applied voltages required to generate such fields are often prohibitive for portable applications. In this work, piezoelectric transformers are used to amplify a low input applied voltage (<30 V) to generate breakdown in air without the need for conventional high-voltage electrical equipment. Piezoelectric transformers (PTs) use their inherent electromechanical resonance to produce a voltage amplification, such that the surface of the piezoelectric exhibits a large surface voltage that can generate corona-like discharges on its corners or on adjacent electrodes. In the proper configuration, these discharges can be used to generate a bulk air flow called an ionic wind. In this work, PT-driven discharges are characterized by measuring the discharge current and the velocity of the induced ionic wind with ionic winds generated using input voltages as low as 7 V. The characteristics of the discharge change as the input voltage increases; this modifies the resonance of the system and subsequent required operating parameters.

  1. Breakdown Voltage of CF3CHCl2 gas an Alternative to SF6 Gas using HV Test and Bonding Energy Methods

    Science.gov (United States)

    Juliandhy, Tedy; Haryono, T.; Suharyanto; Perdana, Indra

    2018-04-01

    For more than two decades of Sulphur Hexafluoride (SF6) gases is used as a gas insulation in high voltage equipment especially in substations. In addition to getting an advantage as an insulating gas. SF6 gas is recognized as one of the greenhouse effect gases that cause global warming. Under the Kyoto Protocol, SF6 gas is one of those gases whose use is restricted and gradually reduced to the presence of a replacement gas for SF6 gas. One of the alternative gas alternatives which have the potential of replacing SF6 gas as an insulating gas in Gas Insulated Switchgear (GIS) equipment in the substation is Dichlorotrifluoroethane (CF3CHCl2) gas. The purpose of this paper is to enable a comparison of breakdown voltage with high voltage test and method of calculating Bonding energy to Dichlorotrifluoroethane gas as substitute gas for SF6 gas. At 0.1 bar gas pressure obtained an average breakdown voltage of 18.68 kV / mm at 25oC chamber temperature and has the highest breakdown voltage at 50oC with a breakdown voltage of 19.56 kV / mm. The CF3CHCl2 gas has great potential as an insulating gas because it has more insulation ability high of SF6 gas, and is part of the gas recommended under the Kyoto Protocol. Gas CF3CHCl2 has the capacity to double the value of electronegativity greater than SF6 gas as a major requirement of gas isolation and has a value of Global Warming Potential (GWP) and Ozone Depleting lower than from SF6 gas.

  2. Long Life Thermal Battery for Sonobuoy

    National Research Council Canada - National Science Library

    Kaun, Thomas

    1998-01-01

    ... to 6.0 hours for sonobuoy application to meet advanced development objectives. As proposed, long life is accomplished by significantly improved heat retention using vacuum/multifoil insulation rather than Microtherm insulation...

  3. Experimental Study of Hydroxy Gas (HHO) Production with Variation in Current, Voltage and Electrolyte Concentration

    Science.gov (United States)

    Alam, Noor; Pandey, K. M.

    2017-08-01

    In this paper, work has been carried out experimentally for the investigation of the effects of variation incurrent, voltage, temperature, chemical concentration and reaction time on the amount of hydroxy gas produced. Further effects on the overall electrolysis efficiency of advance alkaline water is also studied. The hydroxy gas (HHO) has been produced experimentally by the electrolysis of alkaline water with parallel plate electrode of 316L-grade stainless steel. The electrode has been selected on the basis of corrosion resistance and inertness with respect to electrolyte (KOH). The process used for the production of HHO is conventional as compared to the other production processes because of reduced energy consumption, less maintenance and low setup cost. From the experimental results, it has been observed that with increase in voltage, temperature and electrolyte concentration of alkaline solution, the production of hydroxy gas has increased about 30 to 40% with reduction in electrical energy consumption.

  4. Long Life Moving-Bed Zinc Titanate Sorbent

    International Nuclear Information System (INIS)

    Copeland, Robert J.; Cesario, Mike; Feinberg, Daniel A.; Sibold, Jack; Windecker, Brian; Yang, Jing

    1997-01-01

    The objective of this work was to develop and test long-life sorbents for hot gas cleanup. Specifically, we measured the sulfur loading at space velocities typically used for absorption of H 2 S and regenerated the sorbent with diluted air for multiple cycles. Based on the experimental results, we prepared a conceptual design of the sorbent-fabrication system, and estimated the cost of sorbent production and of sulfur removal

  5. Effect of pulsed corona discharge voltage and feed gas flow rate on dissolved ozone concentration

    Energy Technology Data Exchange (ETDEWEB)

    Prasetyaningrum, A., E-mail: ajiprasetyaningrum@gmail.com; Ratnawati,; Jos, B. [Department of Chemical Engineering, Faculty of Engineering, Diponegoro University Jl. Prof. H. Soedarto Tembalang, Semarang, Central Java, Indonesia, 50276 (Indonesia)

    2015-12-29

    Ozonization is one of the methods extensively used for water purification and degradation of organic materials. Ozone (O{sub 3}) is recognized as a powerful oxidizing agent. Due to its strong oxidability and better environmental friendless, ozone increasing being used in domestic and industrial applications. Current technology in ozone production utilizes several techniques (corona discharge, ultra violet radiation and electrolysis). This experiment aimed to evaluating effect of voltage and gas flow rate on ozone production with corona discharge. The system consists of two net-type stainless steel electrode placed in a dielectric barrier. Three pulsed voltage (20, 30, 40 KV) and flow rate (5, 10, 15 L/min) were prepare for operation variable at high frequency (3.7 kHz) with AC pulsed power supply. The dissolved ozone concentration depends on the applied high-voltage level, gas flow rate and the discharge exposure duration. The ozone concentration increases with decreasing gas flow rate. Dissolved ozone concentrations greater than 200 ppm can be obtained with a minimum voltage 40 kV.

  6. Effect of pulsed corona discharge voltage and feed gas flow rate on dissolved ozone concentration

    International Nuclear Information System (INIS)

    Prasetyaningrum, A.; Ratnawati,; Jos, B.

    2015-01-01

    Ozonization is one of the methods extensively used for water purification and degradation of organic materials. Ozone (O 3 ) is recognized as a powerful oxidizing agent. Due to its strong oxidability and better environmental friendless, ozone increasing being used in domestic and industrial applications. Current technology in ozone production utilizes several techniques (corona discharge, ultra violet radiation and electrolysis). This experiment aimed to evaluating effect of voltage and gas flow rate on ozone production with corona discharge. The system consists of two net-type stainless steel electrode placed in a dielectric barrier. Three pulsed voltage (20, 30, 40 KV) and flow rate (5, 10, 15 L/min) were prepare for operation variable at high frequency (3.7 kHz) with AC pulsed power supply. The dissolved ozone concentration depends on the applied high-voltage level, gas flow rate and the discharge exposure duration. The ozone concentration increases with decreasing gas flow rate. Dissolved ozone concentrations greater than 200 ppm can be obtained with a minimum voltage 40 kV

  7. Effect of pulsed corona discharge voltage and feed gas flow rate on dissolved ozone concentration

    Science.gov (United States)

    Prasetyaningrum, A.; Ratnawati, Jos, B.

    2015-12-01

    Ozonization is one of the methods extensively used for water purification and degradation of organic materials. Ozone (O3) is recognized as a powerful oxidizing agent. Due to its strong oxidability and better environmental friendless, ozone increasing being used in domestic and industrial applications. Current technology in ozone production utilizes several techniques (corona discharge, ultra violet radiation and electrolysis). This experiment aimed to evaluating effect of voltage and gas flow rate on ozone production with corona discharge. The system consists of two net-type stainless steel electrode placed in a dielectric barrier. Three pulsed voltage (20, 30, 40 KV) and flow rate (5, 10, 15 L/min) were prepare for operation variable at high frequency (3.7 kHz) with AC pulsed power supply. The dissolved ozone concentration depends on the applied high-voltage level, gas flow rate and the discharge exposure duration. The ozone concentration increases with decreasing gas flow rate. Dissolved ozone concentrations greater than 200 ppm can be obtained with a minimum voltage 40 kV.

  8. Long Life Pavements; Firmes de larga duracion

    Energy Technology Data Exchange (ETDEWEB)

    Mateos Moreno, A.; Marron Fernandez, J. O.; Perez Ayuso, J.

    2009-07-01

    The existence of long-life pavements is not new; they have been built in Europe and the United States for decades. In fact, the concept arises from the observation of in-service roads; it was verified how particular pavements, initially designed for a 20-year service life, did not seem to have reduced the bearing capacity along the time, and its maintenance necessities had been exclusively focused on the wearing course. The base idea of long-life pavements is the existence of a fatigue threshold below which the damage produced by each load application is, in practice, zero or below the healing potential of the asphalt mix. The use practice of long-life pavements design considers a pavements constituted by three asphalt layers, each one with a very specific role: a wearing course that provides with the surface characteristics, an intermediate course that provides with most of the structural capacity and a base course that provides with the fatigue resistance. Furthermore, one of the particularities is the design against specific distress mechanisms. Maintenance strategy also presents specific particularities for long-life pavements. It is essentially focused on the detection of surface deterioration, and the appropriate and timely repair, before the damage extends beyond the wearing course, putting into risk the structural integrity of the pavement. Nowadays, this new way to conceive the design, the construction and the maintenance of road pavements, constitutes one of the main challenges for pavement engineering worldwide. (Author) 5 refs.

  9. High efficiency, long life terrestrial solar panel

    Science.gov (United States)

    Chao, T.; Khemthong, S.; Ling, R.; Olah, S.

    1977-01-01

    The design of a high efficiency, long life terrestrial module was completed. It utilized 256 rectangular, high efficiency solar cells to achieve high packing density and electrical output. Tooling for the fabrication of solar cells was in house and evaluation of the cell performance was begun. Based on the power output analysis, the goal of a 13% efficiency module was achievable.

  10. Kinetics of charged particles in a high-voltage gas discharge in a nonuniform electrostatic field

    Energy Technology Data Exchange (ETDEWEB)

    Kolpakov, V. A., E-mail: kolpakov683@gmail.com; Krichevskii, S. V.; Markushin, M. A. [Korolev Samara National Research University (Russian Federation)

    2017-01-15

    A high-voltage gas discharge is of interest as a possible means of generating directed flows of low-temperature plasma in the off-electrode space distinguished by its original features [1–4]. We propose a model for calculating the trajectories of charges particles in a high-voltage gas discharge in nitrogen at a pressure of 0.15 Torr existing in a nonuniform electrostatic field and the strength of this field. Based on the results of our calculations, we supplement and refine the extensive experimental data concerning the investigation of such a discharge published in [1, 2, 5–8]; good agreement between the theory and experiment has been achieved. The discharge burning is initiated and maintained through bulk electron-impact ionization and ion–electron emission. We have determined the sizes of the cathode surface regions responsible for these processes, including the sizes of the axial zone involved in the discharge generation. The main effect determining the kinetics of charged particles consists in a sharp decrease in the strength of the field under consideration outside the interelectrode space, which allows a free motion of charges with specific energies and trajectories to be generated in it. The simulation results confirm that complex electrode systems that allow directed plasma flows to be generated at a discharge current of hundreds or thousands of milliamperes and a voltage on the electrodes of 0.3–1 kV can be implemented in practice [3, 9, 10].

  11. A Study on Gas Insulation Characteristics for Design Optimization of High Voltage Power Apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Kim, I S; Kim, M K; Seo, K S; Moon, I W; Choi, C K [Korea Electrotechnology Research Institute (Korea, Republic of)

    1996-12-01

    This study aim of obtaining the basic data for gas insulation in the high voltage apparatus and for investigating the breakdown characteristics in uniform field and non-uniform which the geometric construction in the practical power apparatus. In this study, the research results on the insulation technology published earlier are reviewed and the basic data for an optimum design of a high voltage apparatus are obtained thorough the experiment and computer simulation by using a uniform field. The main result are summarized as follows: (A) Investigation on the insulation technology in a large-capacity power apparatus. (B) Investigation on the breakdown characteristics in particle contaminated condition. (C) Investigation on the design in computer simulation. (D) Investigation on the simulation technology of breakdown characteristics. (E) Investigation on breakdown characteristics in the nonuniform field and experiment. (author). refs., figs., tabs.

  12. Reliability of semiconductor and gas-filled diodes for over-voltage protection exposed to ionizing radiation

    Directory of Open Access Journals (Sweden)

    Stanković Koviljka

    2009-01-01

    Full Text Available The wide-spread use of semiconductor and gas-filled diodes for non-linear over-voltage protection results in a variety of possible working conditions. It is therefore essential to have a thorough insight into their reliability in exploitation environments which imply exposure to ionizing radiation. The aim of this paper is to investigate the influence of irradiation on over-voltage diode characteristics by exposing the diodes to californium-252 combined neutron/gamma radiation field. The irradiation of semiconductor over-voltage diodes causes severe degradation of their protection characteristics. On the other hand, gas-filled over-voltage diodes exhibit a temporal improvement of performance. The results are presented with the accompanying theoretical interpretations of the observed changes in over-voltage diode behaviour, based on the interaction of radiation with materials constituting the diodes.

  13. Operational characteristics of a high voltage plasma focus device working with deuterium and heavy gas mixture

    International Nuclear Information System (INIS)

    Zoita, V.; Presura, R.; Gherendi, F.; Dumitrescu-Zoita, C.; Aliaga, R.

    1992-01-01

    The addition of a few neon percents to the deuterium gas filling of a medium energy plasma focus device (PFD) changes dramatically the radiation characteristics of the discharge as well as the pinch configuration. One exceptional result is the generation of high aspect ratio pinches shown clearly and reproducibly on X-ray pinhole camera images and on schlieren pictures. Another remarkable result is that these pinches which show no macroscopic instabilities copiously produce neutrons and hard X-rays. This confirms an experimental fact previously identified on a lower voltage PFD: the macroscopic instabilities do not play the decisive role in the neutronic performance of medium energy PFD's. (Author)

  14. Characterization and gas sensing properties of CuO synthesized by DC directly applying voltage

    Energy Technology Data Exchange (ETDEWEB)

    Klinbumrung, Arrak [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongtem, Titipun [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongtem, Somchai, E-mail: schthongtem@yahoo.com [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2014-09-15

    Highlights: • CuO as a p-type semiconductor. • It was synthesized by directly applying voltage. • A promising material for ammonia detection. - Abstract: CuO microstructure was successfully synthesized by 50 A and 3.6 V DC directly applying voltage. Crystalline structure was characterized by X-ray diffraction (XRD), morphology by scanning and transmission electron microscopy (SEM, TEM). The sample of the 15 min processing time has an irregular shape with diameter about several hundreds of nanometer. Fourier transform infrared (FTIR) spectroscopy, ultraviolet–visible (UV–vis) absorption spectroscopy and photoluminescence (PL) were used to determine vibrational modes and optical properties of the as-synthesized samples: 529 and 585 cm{sup −1} vibrational modes, 3.95 eV band gap, and 402 nm emitting wavelength in violet region of CuO. X-ray photoelectron (XPS) spectroscopy was used to determine chemical composition, Cu(II)O, of the metal oxide surface. Gas sensing performance exposing to NH{sub 3} mixed with air at various working temperatures and NH{sub 3} concentrations of the as-synthesized CuO has the best response at the optimal working temperature of 250 °C: sensitivity of 56.6% exposed to 5275 ppm NH{sub 3}.

  15. Characterization and gas sensing properties of CuO synthesized by DC directly applying voltage

    International Nuclear Information System (INIS)

    Klinbumrung, Arrak; Thongtem, Titipun; Thongtem, Somchai

    2014-01-01

    Highlights: • CuO as a p-type semiconductor. • It was synthesized by directly applying voltage. • A promising material for ammonia detection. - Abstract: CuO microstructure was successfully synthesized by 50 A and 3.6 V DC directly applying voltage. Crystalline structure was characterized by X-ray diffraction (XRD), morphology by scanning and transmission electron microscopy (SEM, TEM). The sample of the 15 min processing time has an irregular shape with diameter about several hundreds of nanometer. Fourier transform infrared (FTIR) spectroscopy, ultraviolet–visible (UV–vis) absorption spectroscopy and photoluminescence (PL) were used to determine vibrational modes and optical properties of the as-synthesized samples: 529 and 585 cm −1 vibrational modes, 3.95 eV band gap, and 402 nm emitting wavelength in violet region of CuO. X-ray photoelectron (XPS) spectroscopy was used to determine chemical composition, Cu(II)O, of the metal oxide surface. Gas sensing performance exposing to NH 3 mixed with air at various working temperatures and NH 3 concentrations of the as-synthesized CuO has the best response at the optimal working temperature of 250 °C: sensitivity of 56.6% exposed to 5275 ppm NH 3

  16. Ionization processes in combined high-voltage nanosecond - laser discharges in inert gas

    Science.gov (United States)

    Starikovskiy, Andrey; Shneider, Mikhail; PU Team

    2016-09-01

    Remote control of plasmas induced by laser radiation in the atmosphere is one of the challenging issues of free space communication, long-distance energy transmission, remote sensing of the atmosphere, and standoff detection of trace gases and bio-threat species. Sequences of laser pulses, as demonstrated by an extensive earlier work, offer an advantageous tool providing access to the control of air-plasma dynamics and optical interactions. The avalanche ionization induced in a pre-ionized region by infrared laser pulses where investigated. Pre-ionization was created by an ionization wave, initiated by high-voltage nanosecond pulse. Then, behind the front of ionization wave extra avalanche ionization was initiated by the focused infrared laser pulse. The experiment was carried out in argon. It is shown that the gas pre-ionization inhibits the laser spark generation under low pressure conditions.

  17. Synergistic effects of liquid and gas phase discharges using pulsed high voltage for dyes degradation in the presence of oxygen.

    Science.gov (United States)

    Yang, Bin; Zhou, Minghua; Lei, Lecheng

    2005-07-01

    The technology of combined liquid and gas phase discharges (LGD) using pulsed high voltage for dyes degradation was developed in this study. Apparent synergistic effects for Acid orange II (AO) degradation in the presence of oxygen were observed. The enhancement of AO degradation rate was around 302%. Furthermore, higher energy efficiency was obtained comparing with individual liquid phase discharge (LD) or gas phase discharge process (GD). The AO degradation in the presence of oxygen by LGD proceeded through the direct ozone oxidation and the ozone decomposition induced by LD. Important operating parameters such as electrode distance, applied voltage, pulse repetition rate, and types of dyes were further investigated.

  18. Possibilities of TWR and long life reactor

    International Nuclear Information System (INIS)

    Sekimoto, Hiroshi; Shimazu, Yoichiro; Handa, Norihiko

    2010-01-01

    Bill Gates identified the need to switch to zero-emission energy and clarified investing in Terra Power developing the TWR (Traveling Wave Reactor) in February 2010. He also visited Toshiba developing small reactor 4S (Super Safe Small and Simple). In Japan design studies of the TWR have been conducted on the CANDLE reactor without refueling and the 4S long life reactor with maintenance free. In this feature article, the state of R and D on the TWR in Japan and IAEA's activities on small reactors without online refueling were reviewed in addition to articles on impacts of Bill Gates' investment in the TWR and state of the TWR development from an interview with John Gilleland of Terra Power. (T. Tanaka)

  19. Discharge runaway in high power impulse magnetron sputtering of carbon: the effect of gas pressure, composition and target peak voltage

    Science.gov (United States)

    Vitelaru, Catalin; Aijaz, Asim; Constantina Parau, Anca; Kiss, Adrian Emil; Sobetkii, Arcadie; Kubart, Tomas

    2018-04-01

    Pressure and target voltage driven discharge runaway from low to high discharge current density regimes in high power impulse magnetron sputtering of carbon is investigated. The main purpose is to provide a meaningful insight of the discharge dynamics, with the ultimate goal to establish a correlation between discharge properties and process parameters to control the film growth. This is achieved by examining a wide range of pressures (2–20 mTorr) and target voltages (700–850 V) and measuring ion saturation current density at the substrate position. We show that the minimum plasma impedance is an important parameter identifying the discharge transition as well as establishing a stable operating condition. Using the formalism of generalized recycling model, we introduce a new parameter, ‘recycling ratio’, to quantify the process gas recycling for specific process conditions. The model takes into account the ion flux to the target, the amount of gas available, and the amount of gas required for sustaining the discharge. We show that this parameter describes the relation between the gas recycling and the discharge current density. As a test case, we discuss the pressure and voltage driven transitions by changing the gas composition when adding Ne into the discharge. We propose that standard Ar HiPIMS discharges operated with significant gas recycling do not require Ne to increase the carbon ionization.

  20. Discharge Onset Voltage Prediction for a Gas-Insulated System Via the Figure-of-Merit Concept

    DEFF Research Database (Denmark)

    Crichton, George C; Vibholm, Svend

    1987-01-01

    The accuracy of discharge onset prediction via thefigur figure-of-merit concept for a strongly electronegative gas is examined. A coaxial system is employed, for which the inner electrode possesses a surface roughness of Ra=35 ¿m. With SF6 as the insulating medium a reference discharge......-onset characteristic is obtained for gas pressures up to 0.8 MPa. From a knowledge of this onset characteristic, the direct calculation of discharge onset voltages in other strongly electronegative gases is undertaken by utilizing thefigur figure-of-merit concept. For gas pressures in the range O.02...

  1. Low-Cost Open-Source Voltage and Current Monitor for Gas Metal Arc Weld 3D Printing

    Directory of Open Access Journals (Sweden)

    A. Pinar

    2015-01-01

    Full Text Available Arduino open-source microcontrollers are well known in sensor applications for scientific equipment and for controlling RepRap 3D printers. Recently low-cost open-source gas metal arc weld (GMAW RepRap 3D printers have been developed. The entry-level welders used have minimal controls and therefore lack any real-time measurement of welder voltage or current. The preliminary work on process optimization of GMAW 3D printers requires a low-cost sensor and data logger system to measure welder current and voltage. This paper reports on the development of a low-cost open-source power measurement sensor system based on Arduino architecture. The sensor system was designed, built, and tested with two entry-level MIG welders. The full bill of materials and open source designs are provided. Voltage and current were measured while making stepwise adjustments to the manual voltage setting on the welder. Three conditions were tested while welding with steel and aluminum wire on steel substrates to assess the role of electrode material, shield gas, and welding velocity. The results showed that the open source sensor circuit performed as designed and could be constructed for <$100 in components representing a significant potential value through lateral scaling and replication in the 3D printing community.

  2. Influence of discharge voltage on the sensitivity of the resultant sputtered NiO thin films toward hydrogen gas

    Energy Technology Data Exchange (ETDEWEB)

    Khalaf, Mohammed K. [Center of Applied Physics, Directorate of Materials Research, Ministry of Science and Technology, Baghdad (Iraq); Mutlak, Rajaa H. [Dept. of Physics, College of Science, University of Baghdad, Ministry of Higher Education and Scientific Research, Baghdad (Iraq); Khudiar, Ausama I., E-mail: ausamaikhudiar@yahoo.com [Center of Applied Physics, Directorate of Materials Research, Ministry of Science and Technology, Baghdad (Iraq); Hial, Qahtan G. [Dept. of Physics, College of Science, University of Baghdad, Ministry of Higher Education and Scientific Research, Baghdad (Iraq)

    2017-06-01

    Nickel oxide thin films were deposited on glass substrates as the main gas sensor for H{sub 2} by the DC sputtering technique at various discharge voltages within the range of 1.8–2.5 kV. Their structural, optical and gas sensing properties were investigated by XRD, AFM, SEM, ultraviolet visible spectroscopy and home-made gas sensing measurement units. A diffraction peak in the direction of NiO (200) was observed for the sputtered films, thereby indicating that these films were polycrystalline in nature. The optical band gap of the films decreased from 3.8 to 3.5 eV when the thickness of the films was increased from 83.5 to 164.4 nm in relation to an increase in the sputtering discharge voltage from 1.8 to 2.5 kV, respectively. The gas sensitivity performance of the NiO films that were formed was studied and the electrical responses of the NiO-based sensors toward different H{sub 2} concentrations were also considered. The sensitivity of the gas sensor increased with the working temperature and H{sub 2} gas concentration. The thickness of the NiO thin films was also an important parameter in determining the properties of the NiO films as H{sub 2} sensors. It was shown in this study that NiO films have the capability to detect H{sub 2} concentrations below 3% in wet air, a feature that allows this material to be used directly for the monitoring of the environment.

  3. Long Life Cold Cathodes for Hall effect Thrusters, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — An electron source incorporating long life, high current density cold cathodes inside a microchannel plate for use with ion thrusters is proposed. Cathode lifetime...

  4. Nonlinear empirical model of gas humidity-related voltage dynamics of a polymer-electrolyte-membrane fuel cell stack

    Science.gov (United States)

    Meiler, M.; Andre, D.; Schmid, O.; Hofer, E. P.

    Intelligent energy management is a cost-effective key path to realize efficient automotive drive trains [R. O'Hayre, S.W. Cha, W. Colella, F.B. Prinz. Fuel Cell Fundamentals, John Wiley & Sons, Hoboken, 2006]. To develop operating strategy in fuel cell drive trains, precise and computational efficient models of all system components, especially the fuel cell stack, are needed. Should these models further be used in diagnostic or control applications, then some major requirements must be fulfilled. First, the model must predict the mean fuel cell voltage very precisely in all possible operating conditions, even during transients. The model output should be as smooth as possible to support best efficient optimization strategies of the complete system. At least, the model must be computational efficient. For most applications, a difference between real fuel cell voltage and model output of less than 10 mV and 1000 calculations per second will be sufficient. In general, empirical models based on system identification offer a better accuracy and consume less calculation resources than detailed models derived from theoretical considerations [J. Larminie, A. Dicks. Fuel Cell Systems Explained, John Wiley & Sons, West Sussex, 2003]. In this contribution, the dynamic behaviour of the mean cell voltage of a polymer-electrolyte-membrane fuel cell (PEMFC) stack due to variations in humidity of cell's reactant gases is investigated. The validity of the overall model structure, a so-called general Hammerstein model (or Uryson model), was introduced recently in [M. Meiler, O. Schmid, M. Schudy, E.P. Hofer. Dynamic fuel cell stack model for real-time simulation based on system identification, J. Power Sources 176 (2007) 523-528]. Fuel cell mean voltage is calculated as the sum of a stationary and a dynamic voltage component. The stationary component of cell voltage is represented by a lookup-table and the dynamic voltage by a parallel placed, nonlinear transfer function. A

  5. Low-Cost Open-Source Voltage and Current Monitor for Gas Metal Arc Weld 3D Printing

    OpenAIRE

    Pinar, A.; Wijnen, B.; Anzalone, G. C.; Havens, T. C.; Sanders, P. G.; Pearce, J. M.

    2015-01-01

    Arduino open-source microcontrollers are well known in sensor applications for scientific equipment and for controlling RepRap 3D printers. Recently low-cost open-source gas metal arc weld (GMAW) RepRap 3D printers have been developed. The entry-level welders used have minimal controls and therefore lack any real-time measurement of welder voltage or current. The preliminary work on process optimization of GMAW 3D printers requires a low-cost sensor and data logger system to measure welder cu...

  6. Development of long-life neutron detectors for the prototype heavy water reactor 'Fugen'

    International Nuclear Information System (INIS)

    Ohteru, Shigeru; Shirayama, Shimpey.

    1981-01-01

    The development of long-life neutron detectors as the flux monitors for the prototype heavy water reactor has been made. Three kinds of neutron monitors, namely start-up monitor (SUM), power up monitor (PUM) and local power monitor (LPM), are provided. The LPM consists of 4 ion chamber type neutron detectors and a guide tube of power calibration monitor (PCM). This is useful for reactor control and fuel soundness monitor. The improvement of the neutron detectors was made for the operation under high neutron flux and gamma-ray heating. For the long-life operation, U-234 was mixed into U-235 for the conversion in the detectors. The ratio of U-234 to U-235 is 3 to 1. The PCM is also an ion chamber type detector with U-235. The mixing ratio of U-234 to U-235 was determined by a test with the JMTR. The characteristic performance was also investigated by the JMTR. After the completion of Fugen, various tests on the long-life detectors were performed with Fugen. It was hard to test the output linearity of the detectors with a large scale reactor. Therefore, it was tested that the operation range of the detectors is within the linear region of detector output. The voltage-current characteristics and the correlation of output current and saturation current were measured. The variation of the neutron sensitivity of the detectors with the cumulative dose was also studied. (Kato, T.)

  7. Current-voltage characteristics of a gas field ion source with a supertip

    International Nuclear Information System (INIS)

    Boerret, R.; Boehringer, K.; Kalbitzer, S.

    1990-01-01

    The field ionisation properties of a supertip, a fine protrusion on top of a regular emitter, have been studied for hydrogen and the lighter rare gases. The parameter set included tip temperature, tip radius, gas temperature and gas pressure. Due to the local field enhancement at the supertip site, angular current intensities of 35 μA sr -1 and values of brightness up to 10 10 A cm -2 sr -1 have been obtained near the optimum temperature of the gas-tip system. At temperatures below this, the gas density reaches values typical for a condensed phase. In geometrical proportion, the regular tip area appears to serve as a gas supply for the supertip current. (author)

  8. The Effect of Bias Voltage and Gas Pressure on the Structure, Adhesion and Wear Behavior of Diamond Like Carbon (DLC Coatings With Si Interlayers

    Directory of Open Access Journals (Sweden)

    Liam Ward

    2014-04-01

    Full Text Available In this study diamond like carbon (DLC coatings with Si interlayers were deposited on 316L stainless steel with varying gas pressure and substrate bias voltage using plasma enhanced chemical vapor deposition (PECVD technology. Coating and interlayer thickness values were determined using X-ray photoelectron spectroscopy (XPS which also revealed the presence of a gradient layer at the coating substrate interface. Coatings were evaluated in terms of the hardness, elastic modulus, wear behavior and adhesion. Deposition rate generally increased with increasing bias voltage and increasing gas pressure. At low working gas pressures, hardness and modulus of elasticity increased with increasing bias voltage. Reduced hardness and modulus of elasticity were observed at higher gas pressures. Increased adhesion was generally observed at lower bias voltages and higher gas pressures. All DLC coatings significantly improved the overall wear resistance of the base material. Lower wear rates were observed for coatings deposited with lower bias voltages. For coatings that showed wear tracks considerably deeper than the coating thickness but without spallation, the wear behavior was largely attributed to deformation of both the coating and substrate with some cracks at the wear track edges. This suggests that coatings deposited under certain conditions can exhibit ultra high flexible properties.

  9. Neutronic feasibility design of a small long-life HTR

    International Nuclear Information System (INIS)

    Ding Ming; Kloosterman, Jan Leen

    2011-01-01

    Highlights: ► We propose the neutronic feasibility design of a small, long lifetime and transportable HTR. ► Comparison of cylindrical, annular and scatter cores of the small block-type HTR. ► The design of the scatter core effectively reduces the number of the fuel block and increases the lifetime and burnup of the reactor. - Abstract: Small high temperature gas-cooled reactors (HTRs) have the advantages of transportability, modular construction and flexible site selection. This paper presents the neutronic feasibility design of a 20 MWth U-Battery, which is a long-life block-type HTR. Key design parameters and possible reactor core configurations of the U-Battery were investigated by SCALE 5.1. The design parameters analyzed include fuel enrichment, the packing fraction of TRISO particles, the radii of fuel compacts and kernels, and the thicknesses of top and bottom reflectors. Possible reactor core configurations investigated include five cylindrical, two annular and four scatter reactor cores for the U-Battery. The neutronic design shows that the 20 MWth U-Battery with a 10-year lifetime is feasible using less than 20% enriched uranium, while the negative values of the temperature coefficients of reactivity partly ensure the inherent safety of the U-Battery. The higher the fuel enrichment and the packing fraction of TRISO particles are, the lower the reactivity swing during 10 years will be. There is an optimum radius of fuel kernels for each value of the fuel compact design parameter (i.e., radius) and a specific fuel lifetime. Moreover, the radius of fuel kernels has a small influence on the infinite multiplication factor of a typical fuel block in the range of 0.2–0.25 mm, when the radius of fuel compacts is 0.6225 cm and the lifetime of the fuel block is 10 years. The comparison of the cylindrical reactor cores with the non-cylindrical ones shows that neutron under-moderation is a basic neutronic characteristic of the reactor core of the U

  10. Thermal re-ignition processes of switching arcs with various gas-blast using voltage application highly controlled by powersemiconductors

    Science.gov (United States)

    Nakano, Tomoyuki; Tanaka, Yasunori; Murai, K.; Uesugi, Y.; Ishijima, T.; Tomita, K.; Suzuki, K.; Shinkai, T.

    2018-05-01

    This paper focuses on a fundamental experimental approach to thermal arc re-ignition processes in a variety of gas flows in a nozzle. Using power semiconductor switches in the experimental system, the arc current and the voltage applied to the arc were controlled with precise timing. With this system, residual arcs were created in decaying phase under free recovery conditions; arc re-ignition was then intentionally instigated by application of artificial voltage—i.e. quasi-transient recovery voltage—to study the arc behaviour in both decaying and re-ignition phases. In this study, SF6, CO2, N2, O2, air and Ar arcs were intentionally re-ignited by quasi-TRV application at 20 μs delay time from initiation of free recovery condition. Through these experiments, the electron density at the nozzle throat was measured using a laser Thomson scattering method together with high speed video camera observation during the re-ignition process. Temporal variations in the electron density from the arc decaying to re-ignition phases were successfully obtained for each gas-blast arc at the nozzle throat. In addition, initial dielectric recovery properties of SF6, CO2, air and Ar arcs were measured under the same conditions. These data will be useful in the fundamental elucidation of thermal arc re-ignition processes.

  11. Personality factors in the Long Life Family Study

    DEFF Research Database (Denmark)

    Andersen, Stacy L; Sun, Jenny X; Sebastiani, Paola

    2013-01-01

    Objectives. To evaluate personality profiles of Long Life Family Study participants relative to population norms and offspring of centenarians from the New England Centenarian Study.Method. Personality domains of agreeableness, conscientiousness, extraversion, neuroticism, and openness were...... assessed with the NEO Five-Factor Inventory in 4,937 participants from the Long Life Family Study (mean age 70 years). A linear mixed model of age and gender was implemented adjusting for other covariates. RESULTS: A significant age trend was found in all five personality domains. On average, the offspring...... generation of long-lived families scored low in neuroticism, high in extraversion, and within average values for the other three domains. Older participants tended to score higher in neuroticism and lower in the other domains compared with younger participants, but the estimated scores generally remained...

  12. Simulation of the build-up phase of a high voltage low pressure gas discharge using Monte-Carlo-methods

    International Nuclear Information System (INIS)

    Niessen, W.

    1990-02-01

    In this report the simulation of a Pseudospark predischarge between anode and cathode using Monte-Carlo-Methods is described. In the early phase of the discharge electric and magnetic self-fields can be neglected. The model is based on a discharge between two infinitely extended capacitor plates. Eleven different collision reactions and two electrode surface effects are taken into account. A Fortran program was developed that computes the built-up of the discharge in time and space. A specially of the code is, that not only electrons and ions are taken into account, but also fast neutral atoms and molecules. Three pairs of diode-length and voltage were investigated at different pressures: 350 kV/5.0 cm, 30 kV/10.0 cm and 6.9 kV/0.7 cm. The working gas was hydrogen. The computations included: The Paschen-curve, the time evolution of the current densities of the electrons at the anode and the ions at the cathode, the space- and time-dependent particle densities, the time-dependent energy distributions of the different particle species, the relative number of the different collision reactions. (orig./HSI) [de

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

    Energy Technology Data Exchange (ETDEWEB)

    Kavitha, A.; Kannan, R. [Department of Physics, University College of Engineering, Anna University, Dindugal-624622 (India); Subramanian, N. Sankara [Department of Physics, Thiagarajar College of Engineering, Madurai -625015, Tamilnadu (India); Loganathan, S. [Ion Plating, Titan Industries Ltd., Hosur - 635126, Tamilnadu (India)

    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.

  14. Investigation of Peculiarities of a High-Voltage Pulsing Corona Discharge in Carbonic Gas and an Feature Using of Such Discharge for CO2 Dissociation

    International Nuclear Information System (INIS)

    Berezina, G.P.; Mirny, V.I.; Omelaenko, O.L.; Us, V.S.

    2006-01-01

    On laboratory stand of plasmochemical reactor the feature of CO 2 dissociation with the purpose of CO production in high-voltage pulsing corona discharge is investigated at a voltage up to 120 kV, a pulse length of a current 0,5 μs a repetition rate up to 100 Hz. Peculiarities of volt-ampere characteristics of such discharge are studied at different pressures of air and carbonic gas in the discharge chamber and construction of an interior electrode. It is established that in conditions of the carried out experiments a maximum efficiency of CO accretion does not exceed 3,5%

  15. Long life technology work at Rockwell International Space Division

    Science.gov (United States)

    Huzel, D. K.

    1974-01-01

    This paper presents highlights of long-life technology oriented work performed at the Space Division of Rockwell International Corporation under contract to NASA. This effort included evaluation of Saturn V launch vehicle mechanical and electromechanical components for potential extended life capabilities, endurance tests, and accelerated aging experiments. A major aspect was evaluation of the components at the subassembly level (i.e., at the interface between moving surfaces) through in-depth wear analyses and assessments. Although some of this work is still in progress, preliminary conclusions are drawn and presented, together with the rationale for each. The paper concludes with a summary of the effort still remaining.

  16. Nuclear incineration method for long life radioactive wastes

    International Nuclear Information System (INIS)

    Matsumoto, Takaaki; Uematsu, Kunihiko.

    1987-01-01

    Nuclear incineration method is the method of converting the long life radioactive nuclides in wastes to short life or stable nuclides by utilizing the nuclear reaction caused by radiation, unlike usual chemical incineration. By the nuclear incineration, the radioactivity of wastes increases in a short period, but the problems at the time of the disposal are reduced because of the decrease of long life radioactive nuclides. As the radiation used for the nuclear incineration, the neutron beam from fission and fusion reactors and accelerators, the proton beam and gamma ray from accelerators have been studied. The object of the nuclear incineration is actinide, Sr-90, Cs-137, I-129 and Tc-99. In particular, waste actinide emits alpha ray, and is strongly toxic, accordingly, the motive of attempting the nuclear incineration is strong. In Japan, about 24t of waste actinide will accumulate by 2000. The principle of the nuclear incineration, and the nuclear incineration using nuclear fission and fusion reactors and accelerators are described. The nuclear incineration using fission reactors was examined for the first time in 1972 in USA. It is most promising because it is feasible by the present technology without particular research and development. (Kako, I.)

  17. Voltage- and Light-Controlled Spin Properties of a Two-Dimensional Hole Gas in p-Type GaAs/AlAs Resonant Tunneling Diodes

    Science.gov (United States)

    Galeti, H. V. A.; Galvão Gobato, Y.; Brasil, M. J. S. P.; Taylor, D.; Henini, M.

    2018-03-01

    We have investigated the spin properties of a two-dimensional hole gas (2DHG) formed at the contact layer of a p-type GaAs/AlAs resonant tunneling diode (RTD). We have measured the polarized-resolved photoluminescence of the RTD as a function of bias voltage, laser intensity and external magnetic field up to 15T. By tuning the voltage and the laser intensity, we are able to change the spin-splitting from the 2DHG from almost 0 meV to 5 meV and its polarization degree from - 40% to + 50% at 15T. These results are attributed to changes of the local electric field applied to the two-dimensional gas which affects the valence band and the hole Rashba spin-orbit effect.

  18. Exceptional memory performance in the Long Life Family Study

    DEFF Research Database (Denmark)

    Barral, Sandra; Cosentino, Stephanie; Costa, Rosann

    2013-01-01

    Research to understand variability at the highest end of the cognitive performance distribution has been scarce. Our aim was to define a cognitive endophenotype based on exceptional episodic memory (EM) performance and to investigate familial aggregation of EM in families from the Long Life Family...... Study (LLFS). Using a sample of 1911 nondemented offspring of long-lived probands, we created a quantitative phenotype, EM (memory z ≥ 1.5), and classified LLFS families as EM and non-EM families based on the number of EM offspring. We then assessed differences in memory performance between LLFS...... = 1.4 × 10(-4)). We demonstrated that there is a familial correlation of the EM endophenotype, suggesting that genetic variants might influence memory performance in long-lived families....

  19. Degradation factors of a new long life cathode

    International Nuclear Information System (INIS)

    Zhang Mingchen; Zhang Honglai; Liu Pukun; Li Yutao

    2011-01-01

    This paper analyses the degradation factors of a new long life coated impregnated cathode after accelerated life test. The surface state of the cathode is investigated with scanning electron microscope (SEM) as well as the content and variation of the various elements on the surface and the longitudinal section of the cathode are analyzed with Auger electron spectroscopy (AES) before and after the life test. The analyzing results with SEM show that the cathode coating shrinks at the life end and leads to a rise in its work function. The analyzing results with AES show that the percent of the W increases and the active materials Ba decreases on the cathode surface at the life end. Furthermore, there is less Ba underneath the cathode surface but still a lot of Ba in the tungsten matrix at the life end.

  20. The safety of high activity long life nuclear waste

    International Nuclear Information System (INIS)

    Devillers, Ch.

    1998-01-01

    The article concerns the deep geological storage for managing high activity long life nuclear waste. He puts forward a context giving a structure to the discussions of those involved concerning an assessment of the safety of a deep geological deposit project. Three main aspects are put forward. The risks for future generations and the time scales to be considered: briefly, the deposit needs to satisfy two functions for protecting man and the environment, namely firstly isolating high activity radionuclides from the biosphere during the time required for their radioactive decay (about ten thousands years), and secondly delay and dilute long life radionuclides without any a priori time limit so as to reduce their effects in the biosphere to extremely low levels. The risks are linked to possible failures of the containment barriers whose causes need to be analysed and be provided against by suitable provisions concerning their design. The definition of these design provisions requires an in depth examination of uncertain elements. The main causes of uncertainty are listed according to the scale of time in question, that is O-10,000 years, 10,000-100,000 years and beyond 100,000 years, stressing the importance of selecting a stable geological site and more generally a solid concept that is not very sensitive in uncertainties. Beyond 100,000 years the extent of uncertainties no longer makes it possible to make realistic predictions. It is thus necessary to consider the alternative scenarios concerning geological and climatic changes and the corresponding increasing risks of radionuclides. The risks in question may be relativized by realizing that on this time scale, the residual activities of soluble and insoluble alpha and beta emitters are comparable to those of a storage centre located on the surface at the end of the monitoring period. Finally, the article considers the approach put forward concerning the safety of a deep geological storage advocated by the French

  1. New flexible thermal control material for long-life satellite

    International Nuclear Information System (INIS)

    Sasaki, Shigekuni; Hasuda, Yoshinori; Ichino, Toshihiro

    1986-01-01

    Flexible thermal control materials are light weight, cheap and excellent in the practical applicability, and are expected to be applied to future long life, large capacity satellites. However, the flexible thermal control materials used at present have the defect that either the space environment withstanding capability or the thermal control performance is poor. Therefore, the authors examined the flexible thermal control materials which are excellent in both these properties, and have developed the thermal control material PEI-OSR using polyether imide films as the substrate. In this study, while comparing with the FEP Teflon with silver vapor deposition, which has been used so far for short life satellites, the long term reliability of the PEI-OSR supposing the use for seven years was examined. As the results, the FEP Teflon with silver vapor deposition caused cracking and separation by irradiation and heat cycle test, and became unusable, but the PEI-OSR did not change its flexibility at all. Also the thermal control performance of the PEI-OSR after the test equivalent to seven years was superior to the initial performance of the Kaptone with aluminum vapor deposition, which has excellent space environment endurance, thus it was clarified that the PEI-OSR is the most excellent for this purpose. (Kako, I.)

  2. Development of long-life low enrichment fuel

    International Nuclear Information System (INIS)

    Gietzen, A.J.; West, G.B.

    1978-01-01

    With only a few exceptions, TRIGA reactors have always used low-enriched-uranium (LEU) fuel with an enrichment of 19.9%. The exceptions have either been converted from the standard low-enriched fuel to the 70% enriched FLIP fuel in order to achieve extended lifetime, or are higher powered reactors which were designed for long life using 93%-enriched uranium during the time when the use and export of highly enriched uranium (HEU) was not restricted. The advent of international policies focusing attention on non-proliferation and safeguards made the HEU fuels obsolete. General Atomic immediately undertook a development effort (nearly two years ago) in order to be in a position to comply with these policies for all future export sales and also to provide a low-enriched alternative to fully enriched plate-type fuels. This important work was subsequently partially supported by the U. S. Department of Energy. The laboratory and production tests have shown that higher uranium densities can be achieved to compensate for reducing the enrichment to 20%, and that the fuels maintain the characteristics of the very thoroughly proven standard TRIGA fuels. In May of this year, General Atomic announced that these fuels were available for TRIGA reactors and for plate-type reactors with power levels up to 15 MW with GA's standard commercial warranty

  3. Safety aspect of long-life small safe power reactors

    International Nuclear Information System (INIS)

    Zaki, S.; Sekimoto, H.

    1995-01-01

    Safety aspects of several design options of long-life small safe fast power reactors using nitride fuel and lead-bismuth as coolant are discussed. In the present study hypothetical accidents are simulated for these reactors, i.e., unprotected simultaneous ULOF (total loss of primary pumping system) and UTOP (rod run out transient over power) accidents, caused by the simultaneous withdrawal of all control rods. The proposed designs have some important safety characteristics as low reactivity swing (only 0.2-0.25$), and negative coolant void coefficient over whole burnup period. Effectively negative value of all components of reactivity during an accident is observed. The safety performances of the balance, pancake, and tall slender type of core, each of them satisfy reactivity and negative coolant void coefficient constraint, against the above accident are compared. The simulation results show that all of the design options can survive the above accidents without the help of reactor scram and without the need of operator actions. (author)

  4. Test results and commercialization plans for long life Stirling generators

    International Nuclear Information System (INIS)

    Erbeznik, R.M.; White, M.A.

    1996-01-01

    Many optimistic predictions regarding commercialization of Stirling engines have been announced over the years, but to date no real successes have emerged. STC is excited to announce the availability of beta prototypes for its RemoteGen trademark family of free-piston Stirling generators. STC is working with suppliers, manufacturers, and beta customers to commercialize the RemoteGen family of generators. STC is proving that these machines overcome previously inhibiting barriers by providing long life, high reliability, cost effective mass production, and market relevance. Stirling power generators are generally acknowledged to offer much higher conversion efficiencies than direct energy conversion systems. Life and reliability, on the other hand, are generally considered superior for direct conversion systems, as established by the exceptional endurance records (though with degradation) for thermoelectric (TE) and photovoltaic (PV) systems. STC's unique approaches combine dynamic system efficiency with static system reliability. The RemoteGen family presently includes a 10-watt RG-10, a 350-watt RG-350, and with 1-kW and 3-kW sizes planned for the future. They all use the same basic configuration with flexure bearings, clearance seals, and moving iron linear alternators. The third generation RG-10 has entered limited production with a radioisotope-fueled version, and a niche market for a propane-fueled version has been identified. Market analysis has led STC to focus on early commercial production of the RG-350. The linear alternator power module portion of the RG-350 is also used in its sister BeCool trademark family of coolers as the linear motor. By using a common power module, both programs will benefit by each other's commercialization efforts. The technology behind the RemoteGen generators, test results, and plans for commercialization are described in this paper

  5. Oil-Free Turbomachinery Technologies for Long-Life, Maintenance-Free Power Generation Applications

    Science.gov (United States)

    Dellacorte, Christopher

    2013-01-01

    Turbines have long been used to convert thermal energy to shaft work for power generation. Conventional turbines rely upon oil-lubricated rotor supports (bearings, seals, etc.) to achieve low wear, high efficiency and reliability. Emerging Oil-Free technologies such as gas foil bearings and magnetic bearings offer a path for reduced weight and complexity and truly maintenance free systems. Oil-Free gas turbines, using gaseous and liquid fuels are commercially available in power outputs to at least 250kWe and are gaining acceptance for remote power generation where maintenance is a challenge. Closed Brayton Cycle (CBC) turbines are an approach to power generation that is well suited for long life space missions. In these systems, a recirculating gas is heated by nuclear, solar or other heat energy source then fed into a high-speed turbine that drives an electrical generator. For closed cycle systems such as these, the working fluid also passes through the bearing compartments thus serving as a lubricant and bearing coolant. Compliant surface foil gas bearings are well suited for the rotor support systems of these advanced turbines. Foil bearings develop a thin hydrodynamic gas film that separates the rotating shaft from the bearing preventing wear. During start-up and shut down when speeds are low, rubbing occurs. Solid lubricants are used to reduce starting torque and minimize wear. Other emerging technologies such as magnetic bearings can also contribute to robust and reliable Oil-Free turbomachinery. In this presentation, Oil-Free technologies for advanced rotor support systems will be reviewed as will the integration and development processes recommended for implementation.

  6. Degradation mechanisms of 4-chlorophenol in a novel gas-liquid hybrid discharge reactor by pulsed high voltage system with oxygen or nitrogen bubbling.

    Science.gov (United States)

    Zhang, Yi; Zhou, Minghua; Hao, Xiaolong; Lei, Lecheng

    2007-03-01

    The effect of gas bubbling on the removal efficiency of 4-chlorophenol (4-CP) in aqueous solution has been investigated using a novel pulsed high voltage gas-liquid hybrid discharge reactor, which generates gas-phase discharge above the water surface simultaneously with the spark discharge directly in the liquid. The time for 100% of 4-CP degradation in the case of oxygen bubbling (7 min) was much shorter than that in the case of nitrogen bubbling (25 min) as plenty of hydrogen peroxide and ozone formed in oxygen atmosphere enhanced the removal efficiency of 4-CP. Except for the main similar intermediates (4-chlorocatechol, hydroquinone and 1,4-benzoquinone) produced in the both cases of oxygen and nitrogen bubbling, special intermediates (5-chloro-3-nitropyrocatechol, 4-chloro-2-nitrophenol, nitrate and nitrite ions) were produced in nitrogen atmosphere. The reaction pathway of 4-CP in the case of oxygen bubbling was oxygen/ozone attack on the radical hydroxylated derivatives of 4-CP. However, in the case of nitrogen bubbling, hydroxylation was the main reaction pathway with effect of N atom on degradation of 4-CP.

  7. Phase control of a Zeeman-split He-Ne gas laser by variation of the gaseous discharge voltage.

    Science.gov (United States)

    Shelton, W N; Hunt, R H

    1992-07-20

    Zeeman-split lasers are useful for precise positioning or motion control. In applications that employ such a laser to control closely the position of a moving system, phase noise in the Zeeman frequency is a serious problem. Control of low-frequency phase noise can be obtained through variation of the external magnetic field by way of a solenoid wound around the laser tube. It is the finding in this work that control of the residual higher-frequency noise of a He-Ne laser can be obtained through small variations of the high voltage that is used to effect the gaseous discharge in the laser tube. The application of the present system is to the control of the path difference in a Fourier-transform interferometric spectrometer.

  8. Method and system for a gas tube-based current source high voltage direct current transmission system

    Science.gov (United States)

    She, Xu; Chokhawala, Rahul Shantilal; Bray, James William; Sommerer, Timothy John; Zhou, Rui; Zhang, Di

    2017-08-29

    A high-voltage direct-current (HVDC) transmission system includes an alternating current (AC) electrical source and a power converter channel that includes an AC-DC converter electrically coupled to the electrical source and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and the DC-AC inverter each include a plurality of legs that includes at least one switching device. The power converter channel further includes a commutating circuit communicatively coupled to one or more switching devices. The commutating circuit is configured to "switch on" one of the switching devices during a first portion of a cycle of the H-bridge switching circuits and "switch off" the switching device during a second portion of the cycle of the first and second H-bridge switching circuits.

  9. Development of stripper films made of high strength, long life carbon nitride

    International Nuclear Information System (INIS)

    Oyaizu, Mitsuhiro; Sugai, Isamu; Yoshida, Koji; Haruyama, Yoichi.

    1994-01-01

    The heavy ion accelerators such as tandem type van de Graaff, linear accelerators, cyclotrons and so on raise the acceleration efficiency usually by producing multivalent ions by making the charge conversion of heavy ions using carbon thin films. However, when the electrons of large atomic number ions of low energy, high intensity current are stripped, the conventional carbon thin films on the market or home made were very short in their life, and have become the cause of remarkably lowering the acceleration efficiency. The concrete objectives of the development are the use of the charge conversion of unstable nuclear ions in the E arena accelerator for JHP of the future project of Institute of Nuclear Study and the manufacture of the carbon films which are used for the charge conversion of the H beam of high energy, but at the time of exchanging the films, there is the problem of the radiation exposure of large amount, therefore, the development of high reliability, long life stripper films has been strongly demanded. The experiment was carried out by controlled carbon arc discharge process using both AC and DC and the ion beam sputtering process using reactive nitrogen gas. The results are reported. (K.I.)

  10. Research on catalysts for long-life closed-cycle CO2 laser oaperation

    Science.gov (United States)

    Sidney, Barry D.; Schryer, David R.; Upchurch, Billy T.; Hess, Robert V.; Wood, George M.

    1987-01-01

    Long-life, closed-cycle operation of pulsed CO2 lasers requires catalytic CO-O2 recombination both to remove O2, which is formed by discharge-induced CO2 decomposition, and to regenerate CO2. Platinum metal on a tin-oxide substrate (Pt/SnO2) has been found to be an effective catalyst for such recombination in the desired temperature range of 25 to 100 C. This paper presents a description of ongoing research at NASA-Langley on Pt/SnO2 catalyzed CO-O2 recombination. Included are studies with rare-isotope gases since rare-isotope CO2 is desirable as a laser gas for enhanced atmospheric transmission. Results presented include: (1) the effects of various catalyst pretreatment techniques on catalyst efficiency; (2) development of a technique, verified in a 30-hour test, to prevent isotopic scrambling when C(O-18) and (O-18)2 are reacted in the presence of a common-isotope Pt/Sn(O-16)2 catalyst; and (3) development of a mathematical model of a laser discharge prior to catalyst introduction.

  11. Catalysts for long-life closed-cycle CO2 lasers

    Science.gov (United States)

    Schryer, David R.; Sidney, Barry D.; Miller, Irvin M.; Hess, Robert V.; Wood, George M.; Batten, Carmen E.; Burney, Lewis G.; Hoyt, Ronald F.; Paulin, Patricia A.; Brown, Kenneth G.

    1987-01-01

    Long-life, closed-cycle operation of pulsed CO2 lasers requires catalytic CO-O2 recombination both to remove O2, which is formed by discharge-induced CO2 decomposition, and to regenerate CO2. Platinum metal on a tin (IV) oxide substrate (Pt/SnO2) has been found to be an effective catalyst for such recombination in the desired temperature range of 25 to 100 C. This paper presents a description of ongoing research at NASA-LaRC on Pt/SnO2 catalyzed CO-O2 recombination. Included are studies with rare-isotope gases since rare-isotope CO2 is desirable as a laser gas for enhanced atmospheric transmission. Results presented include: (1) achievement of 98% to 100% conversion of a stoichiometric mixture of CO and O2 to CO2 for 318 hours (greater than 1 x 10 to the 6th power seconds), continuous, at a catalyst temperature of 60 C, and (2) development of a technique verified in a 30-hour test, to prevent isotopic scrambling when CO-18 and O-18(2) are reacted in the presence of a common-isotope Pt/Sn O-16(2) catalyst.

  12. Inverted Fuel Cell: Room-Temperature Hydrogen Separation from an Exhaust Gas by Using a Commercial Short-Circuited PEM Fuel Cell without Applying any Electrical Voltage.

    Science.gov (United States)

    Friebe, Sebastian; Geppert, Benjamin; Caro, Jürgen

    2015-06-26

    A short-circuited PEM fuel cell with a Nafion membrane has been evaluated in the room-temperature separation of hydrogen from exhaust gas streams. The separated hydrogen can be recovered or consumed in an in situ olefin hydrogenation when the fuel cell is operated as catalytic membrane reactor. Without applying an outer electrical voltage, there is a continuous hydrogen flux from the higher to the lower hydrogen partial pressure side through the Nafion membrane. On the feed side of the Nafion membrane, hydrogen is catalytically split into protons and electrons by the Pt/C electrocatalyst. The protons diffuse through the Nafion membrane, the electrons follow the short-circuit between the two brass current collectors. On the cathode side, protons and electrons recombine, and hydrogen is released. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Advanced, Long-Life Cryocooler Technology for Zero-Boil-Off Cryogen Storage, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Long-life, high-capacity cryocoolers are a critical need for future space systems utilizing stored cryogens. The cooling requirements for planetary and...

  14. Advanced, Long-Life Cryocooler Technology for Zero-Boil-Off Cryogen Storage, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Long-life, high-capacity cryocoolers are a critical need for future space systems utilizing stored cryogens. The cooling requirements for planetary and...

  15. Experimental investigation on the development characteristics of initial electrons in a gas pressurized closing switch under DC voltage

    Science.gov (United States)

    Rongxiao, ZHAI; Mengtong, QIU; Weixi, LUO; Peitian, CONG; Tao, HUANG; Jiahui, YIN; Tianyang, ZHANG

    2018-04-01

    As one of the most important elements in linear transformer driver (LTD) based systems, the gas pressurized closing switches are required to operate with a very low prefire probability during the DC-charging process to ensure reliable operation and stable output of the whole pulsed power system. The most direct and effective way to control the prefire probability is to select a suitable working coefficient. The study of the development characteristics of the initially generated electrons is useful for optimizing the working coefficient and improving the prefire characteristic of the switches. In this paper an ultraviolet pulsed laser is used to generate initial electrons inside the gap volume. A current measuring system is used to measure the time-dependent current generated by the growth of the initial electrons so as to study the development characteristics of the electrons under different working coefficients. Experimental results show that the development characteristics of the initial electrons are influenced obviously by the working coefficient. With the increase of the working coefficient, the development degree of the electrons increases consequently. At the same times, there is a threshold of working coefficient which produces the effect of ionization on electrons. The range of the threshold has a slow growth but remains close to 65% with the gas pressure increase. When the working coefficient increases further, γ processes are starting to be generated inside the gap volume. In addition, an optimal working coefficient beneficial for improving the prefire characteristic is indicated and further tested.

  16. Preliminary Study for Conceptual Design of Advanced Long Life Small Modular Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Tak, Taewoo; Choe, Jiwon; Jeong, Yongjin; Lee, Deokjung [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of); Kim, T. K. [Argonne National Laboratory, Argonne (United States)

    2015-05-15

    As one of the non-water coolant Small-Modular Reactor (SMR) core concepts for use in the mid- to long-term, ANL has proposed a 100 MWe Advanced sodium-cooled Fast Reactor core concept (AFR-100) targeting a small grid, transportable from pre-licensed factories to the remote plant site for affordable supply. Various breed-and-burn core concepts have been proposed to extend the reactor cycle length, which includes CANDLE with a cigar-type depletion strategy, TerraPower reactors with fuel shuffling for effective breeding, et al. UNIST has also proposed an ultra-long cycle fast reactor (UCFR) core concept having the power rating of 1000 MWe. By adopting the breed-and-burn strategies, the UCFR core can maintain criticality for a targeting reactor lifetime of 60 years without refueling. The objective of this project is to develop an advanced long-life SMR core concept by adopting both the small modular design features of the AFR-100 and the long-life breed-and-burn concept of the UCFR. A conceptual design of long life small modular fast reactor is under development by adopting both the small modular design features of the AFR-100 and the long-life breed-and-burn concept of the UCFR. The feasibility of the long-life fast reactor concepts was reviewed to obtain the core design guidelines and the reactor design requirements of long life small modular fast reactor were proposed in this study.

  17. Novel Architecture for a Long-Life, Lightweight Venus Lander

    International Nuclear Information System (INIS)

    Bugby, D.; Seghi, S.; Kroliczek, E.; Pauken, M.

    2009-01-01

    performance insulation as a function of temperature and pressure; (3) a bench-top ambient pressure thermal test of the evaporation system; and (4) a higher fidelity test, to be conducted in a high pressure, high temperature inert gas test chamber, of a small-scale Venus lander prototype (made from two hemispherical interconnecting halves) that includes all of the aforesaid features.22 CFR 125.4(b)(13) applicable

  18. Ultrathin Layered SnSe Nanoplates for Low Voltage, High-Rate, and Long-Life Alkali-Ion Batteries.

    Science.gov (United States)

    Wang, Wei; Li, Peihao; Zheng, Henry; Liu, Qiao; Lv, Fan; Wu, Jiandong; Wang, Hao; Guo, Shaojun

    2017-12-01

    2D electrode materials with layered structures have shown huge potential in the fields of lithium- and sodium-ion batteries. However, their poor conductivity limits the rate performance and cycle stability of batteries. Herein a new colloid chemistry strategy is reported for making 2D ultrathin layered SnSe nanoplates (SnSe NPs) for achieving more efficient alkali-ion batteries. Due to the effect of weak Van der Waals forces, each semiconductive SnSe nanoplate stacks on top of each other, which can facilitate the ion transfer and accommodate volume expansion during the charge and discharge process. This unique structure as well as the narrow-bandgap semiconductor property of SnSe simultaneously meets the requirements of achieving fast ionic and electronic conductivities for alkali-ion batteries. They exhibit high capacity of 463.6 mAh g -1 at 0.05 A g -1 for Na-ion batteries and 787.9 mAh g -1 at 0.2 A g -1 for Li-ion batteries over 300 cycles, and also high stability for alkali-ion batteries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Feasibility study of ultra-long life fast reactor core concept - 028

    International Nuclear Information System (INIS)

    Kim, T.K.; Taiwo, T.A.

    2010-01-01

    An ultra-long life core concept is proposed targeting capital and operational cost reductions and ultra-high discharge burnup in a fast reactor system. The core concept is achieved by de-rating the power density and adopting annular core geometry to maintain criticality for more than 40 years without refueling. The ultra-long life core has a specific power of ∼10 MW/t and an average driver fuel discharge burnup of ∼300 GWd/t. It is assumed such ultra-high burnup fuel can be developed within an advanced fuel cycle program. Several benefits are expected from the ultra-long life core concept such as capital and operational cost reductions, low proliferation risk, and effectively holding LWR spent fuel without disposal until technologies for a closed nuclear fuel cycle are developed and deployed. As future work, safety analysis, development of the advanced core cooling methods, and comparative cost analysis are expected. (authors)

  20. High-voltage picoamperemeter

    Energy Technology Data Exchange (ETDEWEB)

    Bugl, Andrea; Ball, Markus; Boehmer, Michael; Doerheim, Sverre; Hoenle, Andreas; Konorov, Igor [Technische Universitaet Muenchen, Garching (Germany); Ketzer, Bernhard [Technische Universitaet Muenchen, Garching (Germany); Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany)

    2014-07-01

    Current measurements in the nano- and picoampere region on high voltage are an important tool to understand charge transfer processes in micropattern gas detectors like the Gas Electron Multiplier (GEM). They are currently used to e.g. optimize the field configuration in a multi-GEM stack to be used in the ALICE TPC after the upgrade of the experiment during the 2nd long shutdown of the LHC. Devices which allow measurements down to 1pA at high voltage up to 6 kV have been developed at TU Muenchen. They are based on analog current measurements via the voltage drop over a switchable shunt. A microcontroller collects 128 digital ADC values and calculates their mean and standard deviation. This information is sent with a wireless transmitting unit to a computer and stored in a root file. A nearly unlimited number of devices can be operated simultaneously and read out by a single receiver. The results can also be displayed on a LCD directly at the device. Battery operation and the wireless readout are important to protect the user from any contact to high voltage. The principle of the device is explained, and systematic studies of their properties are shown.

  1. Long-life cathode for the Berkeley-type ion source

    International Nuclear Information System (INIS)

    Fink, J.H.; Biagi, L.A.

    1977-01-01

    Preliminary experiments indicate that a hollow cathode, made from impregnated tungsten emitters, can be adapted for the Lawrence Berkeley Laboratory (LBL)/Lawrence Livermore Laboratory (LLL) ion source. Such cathodes could be the basis of a long life, continuously operated positive-ion source

  2. Thorium utilisation in a small long-life HTR. Part III: Composite-rod fuel blocks

    Energy Technology Data Exchange (ETDEWEB)

    Verrue, Jacques, E-mail: jacques.verrue@polytechnique.org [Delft University of Technology, Reactor Institute Delft, Mekelweg 15, 2629 JB Delft (Netherlands); École Polytechnique (Member of ParisTech), 91128 Palaiseau Cedex (France); Ding, Ming, E-mail: dingm2005@gmail.com [Delft University of Technology, Reactor Institute Delft, Mekelweg 15, 2629 JB Delft (Netherlands); Harbin Engineering University, Nantong Street 145, 150001 Harbin (China); Kloosterman, Jan Leen, E-mail: j.l.kloosterman@tudelft.nl [Delft University of Technology, Reactor Institute Delft, Mekelweg 15, 2629 JB Delft (Netherlands)

    2014-02-15

    Highlights: • Composite-rod fuel blocks are proposed for a small block-type HTR. • An axial separation of fuel compacts is the most important feature. • Three patterns are presented to analyse the effects of the spatial distribution. • The spatial distribution has a large influence on the neutron spectrum. • Composite-rod fuel blocks reach a reactivity swing less than 4%. - Abstract: The U-Battery is a small long-life high temperature gas-cooled reactor (HTR) with power of 20 MWth. In order to increase its lifetime and diminish its reactivity swing, the concept of composite-rod fuel blocks with uranium and thorium was investigated. Composite-rod fuel blocks feature a specific axial separation between UO{sub 2} and ThO{sub 2} compacts in fuel rods. The design parameters, investigated by SCALE 6, include the number and spatial distribution of fuel compacts within the rods, the enrichment of uranium, the radii of fuel kernels and fuel compacts, and the packing fractions of uranium and thorium TRISO particles. The analysis shows that a lower moderation ratio and a larger inventory of heavy metals results in a lower reactivity swing. The optimal atomic carbon-to-heavy metal ratio depends on the mass fraction of U-235 and is commonly in the 160–200 range. The spatial distribution of the fuel compacts within the fuel rods has a large influence on the energy spectrum in each fuel compact and thus on the beginning-of-life reactivity and the reactivity swing. At end-of-life, the differences caused by the spatial distribution of the fuel compacts are smaller due to the fissions of U-233 in the ThO{sub 2} fuel compacts. This phenomenon enables to design fuel blocks with a very low reactivity swing, down to less than 4% in a 10-year lifetime. Among three types of thorium fuelled U-Battery blocks, the composite-rod fuel block achieves the highest end-of-life reactivity and the lowest reactivity swing.

  3. Influence of recycling rate increase of aseptic carton for long-life milk on GWP reduction

    International Nuclear Information System (INIS)

    Mourad, Anna Lucia; Garcia, Eloisa E.C.; Vilela, Gustavo Braz; Von Zuben, Fernando

    2008-01-01

    Tetra Pak, through intensive cooperation with its supply chain, increased the post-consumer recycling rate of the aseptic packaging for long-life milk in the last 10 years. In continuation of a previous study that presented a superior overall performance in terms of reduction of the consumption of natural resources, air emissions and most of the water emissions, the objective of the present work was to apply life cycle assessment (LCA) to measure the global warming potential (GWP). The system was assessed using as functional unit 1000 liters of milk packaged in Tetra Pak Aseptic containers. The reduction of greenhouse gas emissions was calculated for recycling rates of 2%, 22%, 30%, 40% and 70% of the post-consumer residues in Scenarios I (only cardboard recycling) and II (total aseptic laminate recycling). Scenario I showed a 14% reduction in GWP, representing 26 kg of avoided CO 2 equiv. emitted due to the efforts of Tetra Pak to increase the recycling rate from 2% (2000) to 22% (2004). If it will be possible to increase the recycling rate to 70% of post-consumer packages in the future, a 48% reduction of GWP could be attained. Methane exhibited the greatest mass reduction among the greenhouse emissions, since it is emitted during the production of cardboard and also as a result of anaerobic degradation in landfills. The total reduction of the energy requirements of the system due to the increase of the recycling rate (from 2% to 22%) is 154 MJ/1000 liters, a saving of 7%. Scenario II (which considers additional polyethylene and aluminum recycling) has a smaller effect on GWP reduction than Scenario I, since PE/AL represent only 25% of the total mass of the container. The major benefit of the recycling of aseptic cartons is the reduction of the amounts of virgin materials required and the consequent reduction of air emissions. The results of this study can be used to encourage the collection of post-consumer milk cartons as part of environmental education

  4. Ti-Sb-Te alloy: a candidate for fast and long-life phase-change memory.

    Science.gov (United States)

    Xia, Mengjiao; Zhu, Min; Wang, Yuchan; Song, Zhitang; Rao, Feng; Wu, Liangcai; Cheng, Yan; Song, Sannian

    2015-04-15

    Phase-change memory (PCM) has great potential for numerous attractive applications on the premise of its high-device performances, which still need to be improved by employing a material with good overall phase-change properties. In respect to fast speed and high endurance, the Ti-Sb-Te alloy seems to be a promising candidate. Here, Ti-doped Sb2Te3 (TST) materials with different Ti concentrations have been systematically studied with the goal of finding the most suitable composition for PCM applications. The thermal stability of TST is improved dramatically with increasing Ti content. The small density change of T0.32Sb2Te3 (2.24%), further reduced to 1.37% for T0.56Sb2Te3, would greatly avoid the voids generated at phase-change layer/electrode interface in a PCM device. Meanwhile, the exponentially diminished grain size (from ∼200 nm to ∼12 nm), resulting from doping more and more Ti, enhances the adhesion between phase-change film and substrate. Tests of TST-based PCM cells have demonstrated a fast switching rate of ∼10 ns. Furthermore, because of the lower thermal conductivities of TST materials, compared with Sb2Te3-based PCM cells, T0.32Sb2Te3-based ones exhibit lower required pulse voltages for Reset operation, which largely decreases by ∼50% for T0.43Sb2Te3-based ones. Nevertheless, the operation voltages for T0.56Sb2Te3-based cells dramatically increase, which may be due to the phase separation after doping excessive Ti. Finally, considering the decreased resistance ratio, TixSb2Te3 alloy with x around 0.43 is proved to be a highly promising candidate for fast and long-life PCM applications.

  5. Advanced Small-Safe Long-Life Lead Cooled Reactor Cores for Future Nuclear Energy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Hyeong; Hong, Ser Gi [Kyung Hee University, Seoul (Korea, Republic of)

    2014-10-15

    One of the reasons for use of the lead or lead-bismuth alloy coolants is the high boiling temperature that avoids the possibility of coolant voiding. Also, these coolants are compatible with air, steam, and water. Therefore, intermediate coolant loop is not required as in the sodium cooled reactors 3. Lead is considered to be more attractive coolant than lead-bismuth alloy because of its higher availability, lower price, and much lower amount of polonium activity by factor of 104 relatively to lead. On the other hand, lead has higher melting temperature of 601K than that of lead-bismuth (398K), which narrows the operating temperature range and also leads to the possibility of freezing and blockage in fresh cores. Neutronically, the lead and lead-bismuth have very similar characteristics to each other. The lead-alloy coolants have lower moderating power and higher scattering without increasing moderation for neutrons below 0.5MeV, which reduces the leakage of the neutrons through the core and provides an excellent reflecting capability for neutrons. Due to the above features of lead or lead-alloy coolants, there have been lots of studies on the small lead cooled core designs. In this paper, small-safe long-life lead cooled reactor cores having high discharge burnup are designed and neutronically analyzed.. The cores considered in this work rates 110MWt (36.7MWe). In this work, the long-life with high discharge burnup was achieved by using thorium or depleted uranium blanket loaded in the central region of the core. Also, we considered a reference core having no blanket for the comparison. This paper provides the detailed neutronic analyses for these small long-life cores and the detailed analyses of the reactivity coefficients and the composition changes in blankets. The results of the core design and analyses show that our small long-life cores can be operated without refueling over their long-lives longer than 45EFPYs (Effective Full Power Year). In this work

  6. Conceptual design study of small long-life PWR based on thorium cycle fuel

    International Nuclear Information System (INIS)

    Subkhi, M. Nurul; Su'ud, Zaki; Waris, Abdul; Permana, Sidik

    2014-01-01

    A neutronic performance of small long-life Pressurized Water Reactor (PWR) using thorium cycle based fuel has been investigated. Thorium cycle which has higher conversion ratio in thermal region compared to uranium cycle produce some significant of 233 U during burn up time. The cell-burn up calculations were performed by PIJ SRAC code using nuclear data library based on JENDL 3.3, while the multi-energy-group diffusion calculations were optimized in whole core cylindrical two-dimension R-Z geometry by SRAC-CITATION. this study would be introduced thorium nitride fuel system which ZIRLO is the cladding material. The optimization of 350 MWt small long life PWR result small excess reactivity and reduced power peaking during its operation

  7. ["A" or ... "The" precious manuscript of the "Long life Elixir" just discovered].

    Science.gov (United States)

    Grelaud, Jean-Pierre

    2012-05-01

    This study relates, describes, analyzes & comments the content of a recently discovered old manuscript, written probably at the beginning of the 18th century, and compares it with the well known "Long life Elixir, or Swedish Elixir", manuscript found on a Swedish doctor who died at 104 years old as a result of a fall from his horse... The origin of this new manuscript can be established from 1700 to 1710, and seems to be probably anterior to the well known Swedish manuscript, meanwhile the text is almost similar,... and also is more complete than this one! We learn that the "Manna" is synonymic here of "fine Rhubarb". Another recipe, unknown on the other manuscript and titled "Dalibour Water" is also published: By similar way, this formula brings some new details, in particular in the exact composition, the preparation and the use of the "Long Life Elixir".

  8. Ultra Long-Life Spacecraft for Long Duration Space Exploration Missions

    Science.gov (United States)

    Chau, Savio

    2002-01-01

    After decades of Solar System exploration, NASA has almost completed the initial reconnaissance, and has been planning for landing and sample return missions on many planets, satellites, comets, and asteroids. The next logical step of space exploration is to expand the frontier into other missions within and outside the solar system. These missions can easily last for more than 30 to 50 years. Most of the current technologies and spacecraft design techniques are not adequate to support such long life missions. Many breakthrough technologies and non-conventional system architecture have to develop in order to sustain such long life missions.Some of these technologies are being developed by the NASA Exploration Team (neXt). Based on the projected requirements for ultra long life missions, the costs and benefits of the required technologies can be quantified. The ultra long-life space system should have four attributes: long-term survivability, administration of consumable resources, evolvability and adaptability, and low-cost long-term operations of the spacecraft. The discussion of survivability is the focus of this paper. Conventional fault tolerant system design has to tolerate only random failures, which can be handled effectively by dual or triple redundancy for a relatively short time. In contrast, the predominant failure mode in an ultra long-life system is the wear-out of components. All active components in the system are destined to fail before the end of the mission. Therefore, an ultra long-life system would require a large number of redundant components. This would be impractical in conventional fault tolerant systems because their fault tolerance techniques are very inefficient. For instance, a conventional dual-string avionics system duplicates the all the components including the processor, memory, and I/O controllers on a spacecraft. However, when the same component in both strings fail (e.g., the processor), the system will fail although all other

  9. The determination of long life radionuclides by means of sector field ICP mass spectrometry

    International Nuclear Information System (INIS)

    Kerl, W.; Becker, J.S.; Dietze, H.J.; Dannecker, W.

    1996-01-01

    Different analytical processes for determining long life radionuclides by means of double-focussing sector field ICP mass spectrometry are described. In determining long life radionuclides by means of ICP-MS, on the one hand the analytical problem areas are in the interference of isobaric atom or molecule ions (eg: 151 Eu + - 151 Sm + , 79 Se + - 39 Ar 40 ArH + ) and on the other hand in the high detection limits when using commercial sample introduction systems (eg: For 129 I). An online coupling of HPLC and ICP-MS was built up for the separation of isobaric atom ions and was tested for the separation of isobaric atom ions and was tested for its efficiency in the separation of lanthanides. Special sample introduction systems for ICP-MS were developed for the analysis of 129 I, by which the sensitivity of detection can be appreciably improved compared to commercial sample introduction systems. (orig.) [de

  10. Assessment of the Free-piston Stirling Convertor as a Long Life Power Convertor for Space

    Science.gov (United States)

    Schreiber, Jeffrey G.

    2001-01-01

    There is currently a renewed interest in the use of free-piston Stirling power convertors for space power applications. More specifically, the Stirling convertor is being developed to be part of the Stirling Radioisotope Power System to supply electric power to spacecraft for NASA deep space science missions. The current development effort involves the Department of Energy, Germantown, MD, the NASA Glenn Research Center, Cleveland, OH, and the Stirling Technology Company, Kennewick, WA. The Stirling convertor will absorb heat supplied from the decay of plutonium dioxide contained in the General Purpose Heat Source modules and convert it into electricity to power the spacecraft. For many years the "potentials" of the free-piston Stirling convertor have been publicized by it's developers. Among these "potentials" were long life and high reliability. This paper will present an overview of the critical areas that enable long life of the free-piston Stirling power convertor, and present some of the techniques that have been used when long life has been achieved.

  11. High resolution studies of the origins of polyatomic ions in inductively coupled plasma-mass spectrometry, Part I. Identification methods and effects of neutral gas density assumptions, extraction voltage, and cone material

    International Nuclear Information System (INIS)

    Ferguson, Jill Wisnewski; Houk, R.S.

    2006-01-01

    Common polyatomic ions (ArO + , NO + , H 2 O + , H 3 O + , Ar 2 + , ArN + , OH + , ArH + , O 2 + ) in inductively coupled plasma-mass spectrometry (ICP-MS) are identified using high mass resolution and studied using kinetic gas temperatures (T gas ) determined from a dissociation reaction approach. Methods for making accurate mass measurements, confirming ion identifications, and correcting for mass bias are discussed. The effects of sampler and skimmer cone composition and extraction voltage on polyatomic ion formation are also explored. Neutral species densities at several locations in the extraction interface are estimated and the corresponding effects of the T gas value are calculated. The results provide information about the origins of background ions and indicate possible locations for their formation or removal

  12. Atomistic Insights into FeF3 Nanosheet: An Ultrahigh-Rate and Long-Life Cathode Material for Li-Ion Batteries.

    Science.gov (United States)

    Yang, Zhenhua; Zhao, Shu; Pan, Yanjun; Wang, Xianyou; Liu, Hanghui; Wang, Qun; Zhang, Zhijuan; Deng, Bei; Guo, Chunsheng; Shi, Xingqiang

    2018-01-24

    Iron fluoride with high operating voltage and theoretical energy density has been proposed as a high-performance cathode material for Li-ion batteries. However, the inertness of pristine bulk FeF 3 results in poor Li kinetics and cycling life. Developing nanosheet-based electrode materials is a feasible strategy to solve these problems. Herein, on the basis of first-principles calculations, first the stability of FeF 3 (012) nanosheet with different atomic terminations under different environmental conditions was systematically studied, then the Li-ion adsorption and diffusion kinetics were thoroughly probed, and finally the voltages for different Li concentrations were given. We found that F-terminated nanosheet is energetically favorable in a wide range of chemical potential, which provide a vehicle for lithium ion diffusion. Our Li-ion adsorption and diffusion kinetics study revealed that (1) the formation of Li dimer is the most preferred, (2) the Li diffusion energy barrier of Li dimer is lower than isolated Li atom (0.17 eV for Li dimer vs 0.22 eV for Li atom), and (3) the diffusion coefficient of Li is 1.06 × 10 -6 cm 2 ·s -1 , which is orders of magnitude greater than that of Li diffusion in bulk FeF 3 (10 -13 -10 -11 cm 2 ·s -1 ). Thus, FeF 3 nanosheet can act as an ultrahigh-rate cathode material for Li-ion batteries. More importantly, the calculated voltage and specific capacity of Li on the FeF 3 (012) nanosheet demonstrate that it has a much more stable voltage profile than bulk FeF 3 for a wide range of Li concentration. So, few layers FeF 3 nanosheet provides the desired long-life energy density in Li-ion batteries. These above findings in the current study shed new light on the design of ultrahigh-rate and long-life FeF 3 cathode material for Li-ion batteries.

  13. New Sodium Cooled Long-Life Cores with Axially Multi-Driver Regions

    International Nuclear Information System (INIS)

    Hyun, Hae Ri; Hong, Ser Gi

    2014-01-01

    In this concept of long-life core (they are sometimes called B-B (Breed and Burn)), tall blanket is placed above the relatively short driver fuel. In the initial stage of burning, the power by fission is mostly generated in the driver region and it moves into the blanket region. The power and flux distributions that are highly peaked in the axial direction propagates slowly from the driver into the blanket region. This concept of long-life core fully utilizes the breeding of blanket in the fast spectra and it can achieve very high burnup of fuel. In this work, we introduce new sodium cooled longlife cores rating 600MWe (1800MWt). In these cores, the driver regions are heterogeneously placed into blanket region so as to achieve stabilized and less peaked axial power distribution as depletion proceeds. At present, our study is focused on only two axial driver regions but this concept can be easily extended onto the multi-driver region concept. The cores designed in this paper have two axial driver regions so as to have stabilized and less peaked axial power distributions as depletion proceeds. The results of the core design and analyses show that the cores have very long-lives longer than -49EFPYs and high discharge burnup higher than 200GWD/kg. Additionally, we considered a long-life core having no blanket. As expected, it was shown that these cores have stabilized and less peaked axial power distribution as the fuel depletes. However, the study shows that the cores having two driver regions still show high initial peaking of the axial power distributions and the core can be optimized by changing the driver fuel height

  14. A Preliminary Design Study of Ultra-Long-Life SFR Cores having Heterogeneous Fuel Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Jung, GeonHee; You, WuSeung; Hong, Ser Gi [Kyung Hee University, Yongin (Korea, Republic of)

    2016-10-15

    The PWR and CANDU reactors have provided electricity for several decades in our country but they have produced lots of spent fuels and so the safe and efficient disposal of these spent fuels is one of the main issues in nuclear industry. This type ultra-long-life cores are quite efficient in terms of the amount of spent fuel generation per electricity production and they can be used as an interim storage for PWR or CANDU spent fuel over several tens of years if they use the PWR or CANDU spent fuel as the initial fuel. Typically, the previous works have considered radially homogeneous fuel assemblies in which only blanket or driver fuel rods are employed and they considered axially or radially heterogeneous core configurations with the radially homogeneous fuel assemblies. These core configurations result in the propagation of the power distribution which can lead to the significant temperature changes for each fuel assembly over the time. In this work, the radially heterogeneous fuel assemblies are employed in new ultra-long-life SFR (Sodium-cooled Fast Reactor) cores to minimize the propagation of power distribution by allowing the power propagation in the fuel assemblies. In this work, new small ultra-long life SFR cores were designed with heterogeneous fuel assemblies having both blanket and driver fuel rods to minimize the propagation of power distribution over the core by allowing power propagation from driver rods to blanket rods in fuel assemblies. In particular, high fidelity depletion calculation coupled with heterogeneous Monte Carlo neutron transport calculation was performed to assess the neutronic feasibility of the ultralong life cores. The results of the analysis showed that the candidate core has the cycle length of 77 EFPYs, a small burnup reactivity swing of 1590 pcm and acceptably small SVRs both at BOC and EOC.

  15. Long-life of a bubble on the surface of a water-alcohol mixture

    Science.gov (United States)

    Rage, Gibran; Hernandez-Sanchez, J. Federico; Wilhelmus, Monica M.; Zenit, Roberto

    2016-11-01

    The lifetime of superficial bubbles has been used traditionally to determine the alcohol content in destilled beverages and spirits. With the proper alcohol content, the bubbles, known as pearls, have a particularly long life which is much longer than that in either pure water or pure ethanol. To understand this peculiar behavior, we conducted controlled experiments in water-ethanol mixtures and in samples of mezcal, an artisanal agave spirit. We assess the effect of the changes in viscosity, surface tension and density of the liquids. Also, we analyzed the effects of surfactants and evaporation rate differences, which lead to Marangoni convection in the draining film.

  16. A novel healthy blood pressure phenotype in the Long Life Family Study

    DEFF Research Database (Denmark)

    Marron, Megan M; Singh, Jatinder; Boudreau, Robert M

    2018-01-01

    in the Long Life Family Study, a cohort of two-generation families selected for longevity. Participants from the offspring generation (n = 2211, ages 32-88) were classified as having healthy BP if their age-adjusted and sex-adjusted SBP z-score was between -1.5 and -0.5. Offspring on antihypertensive...... examining the 419 families, only 44 (10.5%) families met the criteria for the healthy BP phenotype. Both offspring and probands from families with healthy BP performed better on neuropsychological tests that place demands on complex attention and executive function when compared with offspring and probands...

  17. Study 2: the precaution applied to long-life nuclear wastes

    International Nuclear Information System (INIS)

    Marignac, Y.

    2000-01-01

    Among the problems bonded to the energy development, some risks take a global aspect. These risks concerned the resources management, the safety and by-products accumulation (greenhouse gases or nuclear wastes). This document deals with the nuclear wastes problem, which is not studied today on at international scale. A first part presents the general problem of the long-life wastes in France to define an indicator for the nuclear wastes production. This criteria allows to measure the prevention strategy efficiency. A second part deals with financial aspects and calculates the cost-efficiency factor of the nuclear wastes storage facing their processing. (A.L.B.)

  18. Genomewide Association Scan of a Mortality Associated Endophenotype for a Long and Healthy Life in the Long Life Family Study

    DEFF Research Database (Denmark)

    Singh, Jatinder; Minster, Ryan L; Schupf, Nicole

    2017-01-01

    Background: Identification of genes or fundamental biological pathways that regulate aging phenotypes and longevity could lead to possible interventions to increase healthy longevity. Methods: Using data from the Long Life Family Study, we performed genomewide association analyses on an endopheno...

  19. The desing study of high voltage plasma focus for a large fluence neutron source by using a water capacitor bank

    International Nuclear Information System (INIS)

    Ueno, Isao; Kobata, Tadasuke

    1983-01-01

    A new possibility for high intensity neutron source (HINS) would be opened by the plasma focus device if we have a high voltage capacitor bank. A scaling law of neutron yield for D-T gas discharge in plasma focus device is obtained after Imshennik, Filippov and Filippova. The resulting scaling law shows the realizability of the D-T HINS by the use of plasma focus, provided that the device is operated under a high voltage condition. Until now, it has been difficult to construct the high voltage capacitor bank of long life, for example with V 0 =300kV, C 0 =200μF and L 0 --5nH necessary in the level of HINS. It becomes possible to design this capacitor bank by using the coaxial water capacitor which has been developed for the electron and ion beam accelerator. The size of a capacitor designed for V 0 =300kV, C 0 =1μF is phi5m x 22m. Two hundred capacitors are used in parallel in order to get the 200μF. (author)

  20. Study for requirement of advanced long life small modular fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    Tak, Taewoo, E-mail: ttwispy@unist.ac.kr; Choe, Jiwon, E-mail: chi91023@unist.ac.kr; Jeong, Yongjin, E-mail: yjjeong09@unist.ac.kr; Lee, Deokjung, E-mail: deokjung@unist.ac.kr [Ulsan National Institute of Science and Technology, 50, UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan, 689-798 (Korea, Republic of); Kim, T. K., E-mail: tkkim@anl.gov [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60564 (United States)

    2016-01-22

    To develop an advanced long-life SMR core concept, the feasibility of the long-life breed-and-burn core concept has been assessed and the preliminary selection on the reactor design requirement such as fuel form, coolant material has been performed. With the simplified cigar-type geometry of 8m-tall CANDLE reactor concept, it has demonstrated the strengths of breed-and-burn strategy. There is a saturation region in the graph for the multiplication factors, which means that a steady breeding is being proceeded along the axial direction. The propagation behavior of the CANDLE core can be also confirmed through the evolution of the axial power profile. Coolant material is expected to have low melting point, density, viscosity and absorption cross section and a high boiling point, specific heat, and thermal conductivity. In this respect, sodium is preferable material for a coolant of this nuclear power plant system. The metallic fuel has harder spectrum compared to the oxide and carbide fuel, which is favorable to increase the breeding and extend the cycle length.

  1. Tips for a Healthy Long-Life Learned from Space Medicine

    Science.gov (United States)

    Ohshima, Hiroshi; Yamada, Shin; Matsuo, Tomoaki; Yamamoto, Masafumi; Mukai, Chiaki

    2013-02-01

    The field of space medicine is responsible for maintaining astronauts’ health and optimizing their performance. A prolonged stay in space with little gravity results in weakening of the bones and muscles that otherwise support body weight, which is precisely the problem faced by elderly people on Earth. Space medicine provides the means of alleviating such problems. Bone loss, muscle atrophy, and disturbed circadian rhythms are common issues for both astronauts and the elderly alike and can be prevented, if the risks are addressed correctly. To have a healthy long-life, it is important to practice effective health improvement techniques and take preventive measures. The space medicine technologies a for astronauts will provide helpful information to people living in a super aging society. and Japanese medical societies for health promotion. With the aids of the Japanese Society of Physical Fitness and Sports Medicine, the Japanese Orthopaedic Association, and the Japanese Association of Rehabilitation Medicine, JAXA has made a leaflet titled for general citizen to show the tips for a healthy long-life learned from space medicine from the viewpoints of their respective expertise.

  2. Gas

    International Nuclear Information System (INIS)

    1996-01-01

    The French government has decided to modify the conditions of extension of local natural gas authorities to neighbouring districts. The European Union is studying the conditions of internal gas market with the objective of more open markets although considering public service requirements

  3. Voltage regulating circuit

    NARCIS (Netherlands)

    2005-01-01

    A voltage regulating circuit comprising a rectifier (2) for receiving an AC voltage (Vmains) and for generating a rectified AC voltage (vrec), and a capacitor (3) connected in parallel with said rectified AC voltage for providing a DC voltage (VDC) over a load (5), characterized by a unidirectional

  4. All solid state high voltage power supply for neutral beam sources

    International Nuclear Information System (INIS)

    Praeg, W.F.

    1984-01-01

    The conceptual design of a high frequency solid state, high power, high voltage, power system that reacts fast enough to be compatible with the requirements of a neutral beam source is presented. The system offers the potential of significant advantages over conventional power line frequency systems; such as high reliability, long life, relatively little maintenance requirements, compact size and modular design

  5. Development of nuclear safety class filter elements with long life and high quality

    International Nuclear Information System (INIS)

    Zhang Jinghua

    2009-04-01

    This paper describes the development on nuclear safety class filter elements with long life and high quality used for collecting radioactive contaminants, fragments of resin and impurities in primary systems of NPPs. The filter elements made of glass fibre elements are used for PWR, and of paper elements are used for PHWR. During the research, a series of tests for optimization were performed for selection of filter material and the improvement of binder. The flow rate and comprehensive performance have been measured in simulated conditions. The result shows that the application requirements for operational NPPs can be met, and the reliability and safety of the frame are also be verified. The comprehensive performance of the filter elements is equivalent to that of oversea similar products. The products have been used in NPPs in operation. (authors)

  6. High efficiency and long life of a three-phase power conditioner via interleave control

    Directory of Open Access Journals (Sweden)

    Kenji Amei

    2016-01-01

    Full Text Available This study describes the high efficiency and long life of three-phase power conditioners of a photovoltaic (PV system. The current PV system, which is widely spread, has two problems. The first problem is the lifetime of a power conditioner, whereas the other problem is the drop in the efficiency of the conversion because of the characteristics of the solar cell. For those problems, the solar panel and boost chopper circuit were divided into a plurality to configure a power conditioner, and an electrolytic capacitor-less driver with interleave control was realized. The drop in the current generated by the solar cell was suppressed, and an improvement in power generation efficiency was expected. The configuration and principle of a proposed circuit were explained, and results of simulation and experiment were reported.

  7. R and D of the long-life thyratron-tube

    International Nuclear Information System (INIS)

    Oh, J.S.; Namkung, W.; Matsumoto, H.; Akemoto, M.; Dong, X.; Baba, H.; Shintake, T.

    2004-01-01

    Long lifetime over 50,000 hours for the thyratron is essential requirement to provide reasonable availability of the C-band e+e- linear collider. The lifetime and reliability of a solid-state device are not well confirmed yet. There are some examples that show long life of a thyratron. Many thyratrons were dead due to several common causes related to circuits and operation environment rather than intrinsic problems of a device itself. The C-band smart modulator uses an inverter charging method and this scheme affects so much the life of a thyratron. Several valuable feedback systems are easily adopted to enhance the lifetime. There are still unidentified questions to be verified in the thyratron. Close collaboration between laboratories and companies is strongly requested in order to improve the lifetime and performance of a thyratron. (author)

  8. General safety guidelines for looking for a low mass activity-long life waste storage site

    International Nuclear Information System (INIS)

    2008-01-01

    The objective of this document is to define general guidelines which must be followed during the stages of search for a site and stages of design of a storage facility for low activity-long life radioactive wastes, in order to ensure its safety after closure. After having specified the considered wastes, geological shapes, and situations, this document defines the fundamental objective and the associated criteria (protection against chemical risk, radioprotection). It presents the design aspects related to safety (safety principles and functions, waste packages, public works engineering, geological environment, storage concepts). The last part deals with the safety demonstration after site closure which includes the control of some components, the assessment of disturbances in the storage facility or due to its presence, the taking of uncertainty and sensitivity studies into account, the influence of natural events

  9. "Long life" DC brush motor for use on the Mars surveyor program

    Science.gov (United States)

    Braun, David; Noon, Don

    1998-01-01

    DC brush motors have several qualities which make them very attractive for space flight applications. Their mechanical commutation is simple and lightweight, requiring no external sensing and control in order to function properly. They are extremely efficient in converting electrical energy into mechanical energy. Efficiencies over 80% are not uncommon, resulting in high power throughput to weight ratios. However, the inherent unreliability and short life of sliding electrical contacts, especially in vacuum, have driven previous programs to utilize complex brushless DC or the less efficient stepper motors. The Mars Surveyor Program (MSP'98) and the Shuttle Radar Topography Mission (SRTM) have developed a reliable "long life" brush type DC motor for operation in low temperature, low pressure CO2 and N2, utilizing silver-graphite brushes. The original intent was to utilize this same motor for SRTM's space operation, but the results thus far have been unsatisfactory in vacuum. This paper describes the design, test, and results of this development.

  10. Theorising ageing and the question of a long life: eye openings

    Directory of Open Access Journals (Sweden)

    Simon Biggs

    2015-11-01

    Full Text Available A life course perspective, drawing on historical and personal experiences, is used to identify eye-opening concepts that can be used to make sense of the world in terms of personal and social ageing, in the context of intergenerational relationships. Two issues have been identified that characterise a challenge to cultural adaptation: that of generations increasingly becoming approximately the same size as they move from demographic triangles to columns, and that of finding an age-specific purpose for a long life. An analysis of contemporary problems facing gerontology and social policy is given, drawing on the need for complementary life priorities and enhanced generational intelligence. Implications for work, generational rivalry and precarity are examined along with some conclusions on the role of eyeopening conceptual development.

  11. Study of scenarios of long term management of low-activity long-life wastes

    International Nuclear Information System (INIS)

    2012-01-01

    This document reports the study of scenarios for the management of different low-activity long-life radioactive wastes with reference to different French legal texts. After a presentation of the legal and technical context, the report presents different existing and projected storages (description and safety principles for the Cires and Aube centres and for the Cigeo project of deep geological storage centre). It addresses the various aspects of radiferous and graphite waste management on a long term: inventory, parcel, waste peculiarities, management scenarios, assessment of storage in SCR. It also addresses the case of other wastes such as bituminous coated wastes, those presenting a reinforced natural radioactivity or residues of uranium conversion processing. The last part presents the main orientations for the project

  12. Long life nickel electrodes for a nickel-hydrogen cell: Cycle life tests

    Science.gov (United States)

    Lim, H. S.; Verzwyvelt, S. A.

    1985-01-01

    In order to develop a long life nickel electrode for a Ni/H2 cell, the cycle life of nickel electrodes was tested in Ni/H2 boiler plate cells. A 19 test cell matrix was made of various nickel electrode designs including three levels each of plaque mechanical strength, median pore size of the plaque, and active material loading. Test cells were cycled to the end of their life (0.5v) in a 45 minute low Earth orbit cycle regime at 80% depth-of-discharge. It is shown that the active material loading level affects the cycle life the most with the optimum loading at 1.6 g/cc void. Mechanical strength does not affect the cycle life noticeably in the bend strength range of 400 to 700 psi. It is found that the best plaque is made of INCO nickel powder type 287 and has median pore size of 13 micron.

  13. Compact, integrable, and long life time Raman multiline UV-Vis source based on hypocycloid core Kagome HC-PCF

    Science.gov (United States)

    Chafer, M.; Lekiefs, Q.; Gorse, A.; Beaudou, B.; Debord, B.; Gérôme, F.; Benabid, F.

    2017-02-01

    Raman-gas filled HC-PCF has proved to be an outstanding Raman-convertor, as illustrated by the generation of more than 5 octaves wide Raman comb using a hydrogen-filled Kagome HC-PCF pumped with high power picosecond-laser, or the generation of multiline Raman-source in the UV-Vis using a very compact system pumped with micro-chip laser. Whilst these demonstrations are promising, a principal challenge for the industrialization of such a Raman source is its lifetime as the H2 diffusion through silica is high enough to leak out from the fiber within only a few months. Here, we report on a HC-PCF based Raman multiline source with a very long life-span. The system consists of hydrogen filled ultra-low loss HC-PCF contained in highly sealed box, coined CombBox, and pumped with a 532 nm micro-chip laser. This combination is a turnkey multiline Raman-source with a "shoe box" size. The CombBox is a robust and compact component that can be integrated and pumped with any common pulsed laser. When pumped with a 32 mW average power and 1 ns frequency-doubled Nd:Yag microchip laser, this Raman-source generates 24 lines spanning from 355 to 745 nm, and a peak power density per line of 260 mW/nm for the strongest lines. Both the output power and the spectrum remained constant over its monitoring duration of more than six months. The spectrum of this multiline laser superimposes with no less than 17 absorption peaks of fluorescent dyes from the Alexa Fluor family used as biological markers.

  14. Microprocessor-controlled, programmable ramp voltage generator

    International Nuclear Information System (INIS)

    Hopwood, J.

    1978-11-01

    A special-purpose voltage generator has been developed for driving the quadrupole mass filter of a residual gas analyzer. The generator is microprocessor-controlled with desired ramping parameters programmed by setting front-panel digital thumb switches. The start voltage, stop voltage, and time of each excursion are selectable. A maximum of five start-stop levels may be pre-selected for each program. The ramp voltage is 0 to 10 volts with sweep times from 0.1 to 999.99 seconds

  15. Prediction of breakdown voltages in novel gases for high voltage insulation

    Energy Technology Data Exchange (ETDEWEB)

    Koch, M.

    2015-07-01

    This thesis submitted to the Swiss Federal Institute of Technology ETH in Zurich examines the use of sulphur hexafluoride (SF{sub 6}) and similar gases as important insulation media for high voltage equipment. Due to its superior insulation properties, SF{sub 6} is widely used in gas-insulated switchgear. However, the gas also has a very high global warming potential and the content of SF{sub 6} in the atmosphere is constantly increasing. The search for new insulation gases using classical breakdown experiments is discussed. A model for SF{sub 6} based on the stepped leader model is described. This calculates the breakdown voltages in arbitrary electrode configurations and under standard voltage waveforms. Thus, the thesis provides a method for the prediction of breakdown voltages of arbitrary field configurations under standard voltage waveforms for gases with electron-attaching properties. With this, further gases can be characterized for usage as high voltage insulation media.

  16. Prediction of breakdown voltages in novel gases for high voltage insulation

    International Nuclear Information System (INIS)

    Koch, M.

    2015-01-01

    This thesis submitted to the Swiss Federal Institute of Technology ETH in Zurich examines the use of sulphur hexafluoride (SF_6) and similar gases as important insulation media for high voltage equipment. Due to its superior insulation properties, SF_6 is widely used in gas-insulated switchgear. However, the gas also has a very high global warming potential and the content of SF_6 in the atmosphere is constantly increasing. The search for new insulation gases using classical breakdown experiments is discussed. A model for SF_6 based on the stepped leader model is described. This calculates the breakdown voltages in arbitrary electrode configurations and under standard voltage waveforms. Thus, the thesis provides a method for the prediction of breakdown voltages of arbitrary field configurations under standard voltage waveforms for gases with electron-attaching properties. With this, further gases can be characterized for usage as high voltage insulation media

  17. Study on small long-life LBE cooled fast reactor with CANDLE burn-up. Part 1. Steady state research

    International Nuclear Information System (INIS)

    Yan, Mingyu; Sekimoto, Hiroshi

    2008-01-01

    Small long-life reactor is required for some local areas. CANDLE small long-life fast reactor which does not require control rods, mining, enrichment and reprocessing plants can satisfy this demand. In a CANDLE reactor, the shapes of neutron flux, nuclide number densities and power density distributions remain constant and only shift in axial direction. The core with 1.0 m radius, 2.0 m length can realize CANDLE burn-up with nitride (enriched N-15) natural uranium as fresh fuel. Lead-Bismuth is used as coolant. From steady state analysis, we obtained the burn-up velocity, output power distribution, core temperature distribution, etc. The burn-up velocity is less than 1.0 cm/year that enables a long-life design easily. The core averaged discharged fuel burn-up is about 40%. (author)

  18. An innovative conceptual design of the safe and simplified boiling water reactor (SSBWR) with a super-long life core

    Energy Technology Data Exchange (ETDEWEB)

    Yamashita, J. [Hitachi Ltd., Power and Industrial Systems Nuclear System Div., Ibaraki (Japan); Ohtsuka, M.; Fujimura, K.; Hidaka, M.; Nagayoshi, T. [Hitachi Ltd., Power and Industrial Systems R and D Lab., Ibaraki (Japan); Kato, Y. [Tokyo Inst. of Tech. (Japan). Research Lab. for Nuclear Reactors

    2001-07-01

    An innovative concept for the SSBWR has been developed to provide a super-long life core of 20 years with neutron spectrum shift due to dilution from heavy to light water for coolant and to represent a passive core safety system with infinite grace period. Operability and maintainability can be largely improved by the super-long life core, reduction of the number of active components, and RPV renewal with no exchange of fuel assemblies, which can also significantly reduce the possibility of nuclear proliferation. (author)

  19. Neutronic feasibility of an LMFBR super long-life core (SLLC)

    International Nuclear Information System (INIS)

    Kawashima, Masatoshi; Aoki, Katsutada; Arie, Kazuo; Tsuboi, Yasushi

    1988-01-01

    The LMFBR Super Long-Life Core (SLLC) concept has evolved over the last few years as one of the targets of innovative approaches for future FBR cost reduction. An idea for SLLC has been developed wherein the core lifetime is extended up to the plant life of about 30 years by applying the radially and axially multi-zoned core concept (the improved homogeneous core concept). The main purpose of the present study is placed on the evaluation of neutronic feasibility of the 1000 MWe class SLLC concept. The core size of the present SLLC, which is approximately 3 to 4 times as large as those of the current 1000 MWe core design, was determined by the limit of the maximum fast neutron fluence level, which was tentatively assumed to be 5-6x10 23 nvt as the target of the future development of advanced cladding materials. Emphasis is placed on the discussion of neutronic performances of cores with oxide fuels rather than metal or carbide fuels. The present study has shown that proper zoning of the different plutonium enrichment fuels at the initial core makes it possible to achieve small enough reactivity loss during 30-year burnup while satisfying mild variation of the subassembly power distributions using a higher fuel volume fraction of about 50%. Effects of important neutronic parameters on the core performances are also discussed. (orig.)

  20. Preparation and properties of silicone fouling release coatings with long-life afterglow fluorescent

    Directory of Open Access Journals (Sweden)

    Zhang Zhanping

    2017-01-01

    Full Text Available Based on polydimethylsiloxane, three-component coatings were prepared with different content of luminescence powder. The results showed that the illuminance of coatings increases with the content of luminescence powder, decays exponentially with the afterglow time, increases exponentially with the increase of exposure time. The afterglow illuminance augments with irradiated light illuminance. All coatings are hydrophobic and oleophilic. Surface free energy decreases with the increase of luminescence powder. They have highest impact-resistance and bend flexibility. The luminescence powder does not change obviously the shore hardness, tensile breaking strength, breaking elongation rate, elastic modular and roughness of coatings. The static test panels in sea generally could be covered obviously by biofouling including sponges, bryophytes and mussels, hydra, kelp, green algae after 2 months of immersion during growing season. But it never found that the barnacle attached on the coating surface during 4 years of immersion test. The static anti-fouling ability of the coatings is very limited. In addition, the sea creatures attached on the coating surface can be easily removed; even attached organisms will fall off and expose again the smooth coating surface. Consequently, all coatings with long-life afterglow fluorescent have a significant effect on preventing adhesion of barnacle and fouling-release performance.

  1. Improved structure and long-life blanket concepts for heliotron reactors

    International Nuclear Information System (INIS)

    Sagara, A.; Imagawa, S.; Mitarai, O.

    2005-01-01

    New design approaches are proposed for the LHD-type heliotron D-T demo-reactor FFHR2 to solve the key engineering issues of blanket space limitation and replacement difficulty. A major radius of over 14m is selected to permit a blanket-shield thickness of about 1m and to reduce the neutron wall loading and toroidal field, while achieving an acceptable cost of electricity. Two sets of optimization are successfully carried out. One is to reduce the magnetic hoop force on the helical coil support structures by adjustment of the helical winding coil pitch parameter and the poloidal coils design, which facilitates expansion of the maintenance ports. The other is a long-life blanket concept using carbon armour tiles that soften the neutron energy spectrum incident on the self-cooled flibe-reduced activation ferritic steel blanket. In this adaptation of the spectral-shifter and tritium breeder blanket (STB) concept a local tritium breeding ratio over 1.2 is feasible by optimized arrangement of the neutron multiplier Be in the carbon tiles, and the radiation shielding of the superconducting magnet coils is also significantly improved. Using constant cross sections of a helically winding shape, the 'screw coaster' concept is proposed to replace in-vessel components such as the STB armour tiles. The key R and D issues for developing the STB concept, such as radiation effects on carbon and enhanced heat transfer of Flibe, are elucidated. (author)

  2. Improved structure and long-life blanket concepts for heliotron reactors

    Science.gov (United States)

    Sagara, A.; Imagawa, S.; Mitarai, O.; Dolan, T.; Tanaka, T.; Kubota, Y.; Yamazaki, K.; Watanabe, K. Y.; Mizuguchi, N.; Muroga, T.; Noda, N.; Kaneko, O.; Yamada, H.; Ohyabu, N.; Uda, T.; Komori, A.; Sudo, S.; Motojima, O.

    2005-04-01

    New design approaches are proposed for the LHD-type heliotron D-T demo-reactor FFHR2 to solve the key engineering issues of blanket space limitation and replacement difficulty. A major radius of over 14 m is selected to permit a blanket-shield thickness of about 1 m and to reduce the neutron wall loading and toroidal field, while achieving an acceptable cost of electricity. Two sets of optimization are successfully carried out. One is to reduce the magnetic hoop force on the helical coil support structures by adjustment of the helical winding coil pitch parameter and the poloidal coils design, which facilitates expansion of the maintenance ports. The other is a long-life blanket concept using carbon armour tiles that soften the neutron energy spectrum incident on the self-cooled flibe-reduced activation ferritic steel blanket. In this adaptation of the spectral-shifter and tritium breeder blanket (STB) concept a local tritium breeding ratio over 1.2 is feasible by optimized arrangement of the neutron multiplier Be in the carbon tiles, and the radiation shielding of the superconducting magnet coils is also significantly improved. Using constant cross sections of a helically winding shape, the 'screw coaster' concept is proposed to replace in-vessel components such as the STB armour tiles. The key R&D issues for developing the STB concept, such as radiation effects on carbon and enhanced heat transfer of Flibe, are elucidated.

  3. Thorium Fuel Utilization Analysis on Small Long Life Reactor for Different Coolant Types

    Science.gov (United States)

    Permana, Sidik

    2017-07-01

    A small power reactor and long operation which can be deployed for less population and remote area has been proposed by the IAEA as a small and medium reactor (SMR) program. Beside uranium utilization, it can be used also thorium fuel resources for SMR as a part of optimalization of nuclear fuel as a “partner” fuel with uranium fuel. A small long-life reactor based on thorium fuel cycle for several reactor coolant types and several power output has been evaluated in the present study for 10 years period of reactor operation. Several key parameters are used to evaluate its effect to the reactor performances such as reactor criticality, excess reactivity, reactor burnup achievement and power density profile. Water-cooled types give higher criticality than liquid metal coolants. Liquid metal coolant for fast reactor system gives less criticality especially at beginning of cycle (BOC), which shows liquid metal coolant system obtains almost stable criticality condition. Liquid metal coolants are relatively less excess reactivity to maintain longer reactor operation than water coolants. In addition, liquid metal coolant gives higher achievable burnup than water coolant types as well as higher power density for liquid metal coolants.

  4. Development of 4S and related technologies (2). Long life metallic fuel

    International Nuclear Information System (INIS)

    Yacout, A.M.; Tsuboi, Y.; Ueda, N.

    2009-01-01

    This paper provides an overview of the long life metallic fuel to be used in the 4S reactor. The 4S fuel design is presented and implications of its characteristics on fuel performance are discussed. Main design characteristics include the long fuel life time of 30 years and the wider and longer fuel pins compared to EBR-II and FFTF fuel pins. The LIFE-METAL fuel performance code was used to evaluate the performance of the 4S fuel design. The code has been validated using post irradiation examination data of metallic fuel irradiated in EBR-II. The performance evaluation shows the benign nature of the design. The design enables the fuel to perform adequately during reactor operations without violating any of a conservative set of steady state design criteria. A survey evaluation of the fuel performance is also presented. This performance bounding evaluation took into account possible fuel swelling behavior and cladding temperature range that represents worst case scenarios. The evaluation showed that the fuel maintains its integrity even under those worst case conditions. (author)

  5. High voltage systems

    International Nuclear Information System (INIS)

    Martin, M.

    1991-01-01

    Industrial processes usually require electrical power. This power is used to drive motors, to heat materials, or in electrochemical processes. Often the power requirements of a plant require the electric power to be delivered at high voltage. In this paper high voltage is considered any voltage over 600 V. This voltage could be as high as 138,000 V for some very large facilities. The characteristics of this voltage and the enormous amounts of power being transmitted necessitate special safety considerations. Safety must be considered during the four activities associated with a high voltage electrical system. These activities are: Design; Installation; Operation; and Maintenance

  6. 49 CFR Appendix B to Part 564 - Information To Be Submitted for Long Life Replaceable Light Sources of Limited Definition

    Science.gov (United States)

    2010-10-01

    ...—Information To Be Submitted for Long Life Replaceable Light Sources of Limited Definition I. Filament or... Source that Operates With a Ballast and Rated Life of the Light Source/Ballast Combination. A. Maximum power (in watts). B. Luminous Flux (in lumens). C. Rated laboratory life of the light source/ballast...

  7. Thorium utilization in a small long-life HTR. Part II: Seed-and-blanket fuel blocks

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Ming, E-mail: dingming@hrbeu.edu.cn [Delft University of Technology, Reactor Institute Delft, Mekelweg 15, 2629 JB Delft (Netherlands); Harbin Engineering University, Nantong Street 145, 150001 Harbin (China); Kloosterman, Jan Leen [Delft University of Technology, Reactor Institute Delft, Mekelweg 15, 2629 JB Delft (Netherlands)

    2014-02-15

    Highlights: • Seed-and-blanket (S and B) fuel blocks are proposed for a small block-type HTR. • S and B fuel blocks consist of a seed region (UO{sub 2}) and a blanket region (ThO{sub 2}). • The neutronic performance of S and B fuel blocks are analyzed using SCALE 6. • Three S and B fuel blocks with a reactivity swing of 0.1 Δk are recommended. • S and B fuel blocks are compared with thorium MOX fuel blocks. - Abstract: In order to utilize thorium in high temperature gas-cooled reactors (HTRs), the concept of seed-and-blanket (S and B) fuel block is introduced into the U-Battery, which is a long-life block-type HTR with a thermal power of 20 MWth. A S and B fuel block consists of a seed region with uranium in the center, and a blanket region with thorium. The neutronic performance, such as the multiplication factor, conversion ratio and reactivity swing, of a typical S and B fuel block was investigated by SCALE 6.0 by parametric analysis of the composition parameters and geometric parameters of the fuel block for the U-Battery application. Since the purpose of U-235 in the S and B fuel block is to ignite the fission reactions in the fuel block, 20% enriched uranium is recommended for the S and B fuel block. When the ratio of the number of carbon to heavy metal atoms changes with the geometric parameters of the fuel block in the range of 200–250, the reactivity swing reaches very small values. Furthermore, for a reactivity swing of 0.1 Δk during 10 effective full power years, three configurations with 36, 54 and 78 UO{sub 2} fuel rods are recommended for the application of the U-Battery. The comparison analysis of the S and B fuel block with the Th/U MOX fuel block shows that the former has a longer lifetime and a lower reactivity swing.

  8. Thorium utilization in a small long-life HTR. Part I: Th/U MOX fuel blocks

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Ming, E-mail: dingm2005@gmail.com [Delft University of Technology, Reactor Institute Delft, Mekelweg 15, 2629 JB, Delft (Netherlands); Harbin Engineering University, Nantong Street 145, 150001 Harbin (China); Kloosterman, Jan Leen, E-mail: j.l.kloosterman@tudelft.nl [Delft University of Technology, Reactor Institute Delft, Mekelweg 15, 2629 JB, Delft (Netherlands)

    2014-02-15

    Highlights: • We propose thorium MOX (TMOX) fuel blocks for a small block-type HTR. • The TMOX fuel blocks with low-enriched uranium are recommended. • More thorium decreases the reactivity swing of the TMOX fuel blocks. • Thorium reduces the negative temperature coefficient of the TMOX fuel blocks. • Thorium increases the conversion ratio of the TMOX fuel blocks. - Abstract: The U-Battery is a small, long-life and transportable high temperature gas-cooled reactor (HTR). The neutronic features of a typical fuel block with uranium and thorium have been investigated for a application of the U-Battery, by parametrically analyzing the composition and geometric parameters. The type of fuel block is defined as Th/U MOX fuel block because uranium and thorium are assumed to be mixed in each fuel kernel as a form of (Th,U)O{sub 2}. If the initially loaded mass of U-235 is mostly consumed in the early period of the lifetime of Th/U MOX fuel block, low-enriched uranium (LEU) as ignited fuel will not largely reduce the neutronic performance of the Th/U MOX fuel block, compared with high-enriched uranium. The radii of fuel kernels and fuel compacts and packing fraction of TRISO particles determine the atomic ratio of the carbon to heavy metal. When the ratio is smaller than 400, the difference among them due to double heterogeneous effects can be neglected for the Th/U MOX fuel block. In the range between 200 and 400, the reactivity swing of the Th/U MOX fuel block during 10 years is sufficiently small. The magnitude of the negative reactivity temperature coefficients of the Th/U MOX fuel block decreases by 20–45%, which is positive to reduce temperature defect of the Th/U MOX fuel block. The conversion ratio (CR) of the fuel increases from 0.48 (typical CR of the LEU-fueled U-Battery) to 0.78. The larger conversion ratio of the Th/U MOX fuel block reduces the reactivity swing during 10 years for the U-Battery.

  9. Trans-Uranium Doping Utilization for Increasing Protected Plutonium Proliferation of Small Long Life Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Permana, Sidik [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology 2-12-1-N1-17, O-okayama, Meguro-ku, Tokyo 152-8550 (Japan); Nuclear and Biophysics Research Group, Department of Physics, Bandung Institute of Technology, Gedung Fisika, Jl. Ganesha 10, Bandung 40132 (Indonesia); Suud, Zaki [Nuclear and Biophysics Research Group, Department of Physics, Bandung Institute of Technology, Gedung Fisika, Jl. Ganesha 10, Bandung 40132 (Indonesia); Suzuki, Mitsutoshi [Japan Atomic Energy Agency, Nuclear Non-proliferation Science and Technology Center, 2-4 Shirane Shirakata, Tokai-mura, Ibaraki, 319-1195 (Japan)

    2009-06-15

    Scientific approaches are performed by adopting some methodologies in order to increase a material 'barrier' in plutonium isotope composition by increasing the even mass number of plutonium isotope such as Pu-238, Pu-240 and Pu-242. Higher difficulties (barrier) or more complex requirement for peaceful use of nuclear materials, material fabrication and handling and isotopic enrichment can be achieved by a higher isotopic barrier. Higher barrier which related to intrinsic properties of plutonium isotopes with even mass number (Pu-238, Pu-240 and Pu-242), in regard to their intense decay heat (DH) and high spontaneous fission neutron (SFN) rates were used as a parameter for improving the proliferation resistance of plutonium itself. Pu-238 has relatively high intrinsic characteristics of DH (567 W/kg) and SFN rate of 2660 n/g/s can be used for making a plutonium characteristics analysis. Similar characteristics with Pu-238, other even mass number of plutonium isotopes such as Pu-240 and Pu-242 have been shown in regard to SFN values. Those even number mass of plutonium isotope contribute to some criteria of plutonium characterization which will be adopted for present study such as IAEA, Pellaud and Kessler criteria (IAEA, 1972; Pellaud, 2002; and Kessler, 2004). The study intends to evaluate the trans-uranium doping effect for increasing protected plutonium proliferation in long-life small reactors. The development of small and medium reactor (SMR) is one of the options which have been adopted by IAEA as future utilization of nuclear energy especially for less developed countries (Kuznetsov, 2008). The preferable feature for small reactors (SMR) is long life operation time without on-site refueling and in the same time, it includes high proliferation resistance feature. The reactor uses MOX fuel as driver fuel for two different core types (inner and outer core) with blanket fuel arrangement. Several trans-uranium doping and some doping rates are evaluated

  10. Quality changes of long-life foods during three-month storage at different temperatures

    Directory of Open Access Journals (Sweden)

    Zuzana Bubelová

    2017-01-01

    Full Text Available The aim of this study was to describe quality changes of eight long-life foods (instant potato purée with milk, instant goulash soup, canned white-type cheese, pre-baked baguette, szeged goulash meal-ready-to-eat, canned chicken meat, pork pate and canned tuna fish during three-month storage at 4 different temperatures (-18 °C, 5 °C, 23 °C and 40 °C. These temperatures were chosen to simulate various climatic conditions in which these foods could be used to ensure the boarding during crisis situations and military operations to provide high level of sustainability. Foods were assessed in terms of microbiological (total number of aerobic and/or facultative anaerobic mesophilic microorganisms, number of aerobic and anaerobic spore-forming microorganisms, number of enterobacteria, number of yeasts and/or moulds, chemical (pH-values, dry matter, fat, crude protein, ammonia and thiobarbituric acid reactive substances contents, texture profile (hardness and sensory (appearance, consistency, firmness, flavour and off-flavour analyses. Microbiological analyses showed expected results with the exception of szeged goulash, pork pate and tuna fish, which, although being sterilised products, contained some counts of bacteria. The decrease of pH-values and increase of dry matter, ammonia and thiobarbituric acid reactive substances contents were observed during the storage of all foods due to prolonged storage time and/or elevated storage temperature. Furthermore, according to texture profile analysis, hardness of cheese and baguette rose as a result of both storage temperature and time. Finally, the highest storage temperature (40 °C resulted in a deterioration of sensory quality (especially flavour of most foods; the exceptions were pate and tuna fish which retained good sensory quality throughout 3-month storage at all temperatures.

  11. Production of engineered long-life and male sterile Pelargonium plants

    Directory of Open Access Journals (Sweden)

    García-Sogo Begoña

    2012-08-01

    Full Text Available Abstract Background Pelargonium is one of the most popular garden plants in the world. Moreover, it has a considerable economic importance in the ornamental plant market. Conventional cross-breeding strategies have generated a range of cultivars with excellent traits. However, gene transfer via Agrobacterium tumefaciens could be a helpful tool to further improve Pelargonium by enabling the introduction of new genes/traits. We report a simple and reliable protocol for the genetic transformation of Pelargonium spp. and the production of engineered long-life and male sterile Pelargonium zonale plants, using the pSAG12::ipt and PsEND1::barnase chimaeric genes respectively. Results The pSAG12::ipt transgenic plants showed delayed leaf senescence, increased branching and reduced internodal length, as compared to control plants. Leaves and flowers of the pSAG12::ipt plants were reduced in size and displayed a more intense coloration. In the transgenic lines carrying the PsEND1::barnase construct no pollen grains were observed in the modified anther structures, which developed instead of normal anthers. The locules of sterile anthers collapsed 3–4 days prior to floral anthesis and, in most cases, the undeveloped anther tissues underwent necrosis. Conclusion The chimaeric construct pSAG12::ipt can be useful in Pelargonium spp. to delay the senescence process and to modify plant architecture. In addition, the use of engineered male sterile plants would be especially useful to produce environmentally friendly transgenic plants carrying new traits by preventing gene flow between the genetically modified ornamentals and related plant species. These characteristics could be of interest, from a commercial point of view, both for pelargonium producers and consumers.

  12. Genome-wide Association Study of Personality Traits in the Long Life Family Study

    Directory of Open Access Journals (Sweden)

    Harold T Bae

    2013-05-01

    Full Text Available Personality traits have been shown to be associated with longevity and healthy aging. In order to discover novel genetic modifiers associated with personality traits as related with longevity, we performed a genome-wide association study (GWAS on personality factors assessed by NEO-FFI in individuals enrolled in the Long Life Family Study (LLFS, a study of 583 families (N up to 4595 with clustering for longevity in the United States and Denmark. Three SNPs, in almost perfect LD, associated with agreeableness reached genome-wide significance (p<10-8 and replicated in an additional sample of 1279 LLFS subjects, although one (rs9650241 failed to replicate and the other two were not available in two independent replication cohorts, the Baltimore Longitudinal Study of Aging and the New England Centenarian Study. Based on 10,000,000 permutations, the empirical p-value of 2X10-7 was observed for the genome-wide significant SNPs. Seventeen SNPs that reached marginal statistical significance in the two previous GWASs (p-value < 10-4 and 10-5, were also marginally significantly associated in this study (p-value < 0.05, although none of the associations passed the Bonferroni correction. In addition, we tested age-by-SNP interactions and found some significant associations. Since scores of personality traits in LLFS subjects change in the oldest ages, and genetic factors outweigh environmental factors to achieve extreme ages, these age-by-SNP interactions could be a proxy for complex gene-gene interactions affecting personality traits and longevity.

  13. Long-Life, Lightweight, Multi-Roller Traction Drives for Planetary Vehicle Surface Exploration

    Science.gov (United States)

    Klein, Richard C.; Fusaro, Robert L.; Dimofte, Florin

    2012-01-01

    lubricant coatings, thus necessitating the use of liquid lubricants for long life.

  14. Low voltage arc formation in railguns

    Science.gov (United States)

    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.

  15. Voltage regulator for generator

    Energy Technology Data Exchange (ETDEWEB)

    Naoi, K

    1989-01-17

    It is an object of this invention to provide a voltage regulator for a generator charging a battery, wherein even if the ambient temperature at the voltage regulator rises abnormally high, possible thermal breakage of the semiconductor elements constituting the voltage regulator can be avoided. A feature of this invention is that the semiconductor elements can be protected from thermal breakage, even at an abnormal ambient temperature rise at the voltage regulator for the battery charging generator, by controlling a maximum conduction ratio of a power transistor in the voltage regulator in accordance with the temperature at the voltage regulator. This is achieved through a switching device connected in series to the field coil of the generator and adapted to be controlled in accordance with an output voltage of the generator and the ambient temperature at the voltage regulator. 6 figs.

  16. Automatic voltage imbalance detector

    Science.gov (United States)

    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. Technological Aspects: High Voltage

    International Nuclear Information System (INIS)

    Faircloth, D C

    2013-01-01

    This paper covers the theory and technological aspects of high-voltage design for ion sources. Electric field strengths are critical to understanding high-voltage breakdown. The equations governing electric fields and the techniques to solve them are discussed. The fundamental physics of high-voltage breakdown and electrical discharges are outlined. Different types of electrical discharges are catalogued and their behaviour in environments ranging from air to vacuum are detailed. The importance of surfaces is discussed. The principles of designing electrodes and insulators are introduced. The use of high-voltage platforms and their relation to system design are discussed. The use of commercially available high-voltage technology such as connectors, feedthroughs and cables are considered. Different power supply technologies and their procurement are briefly outlined. High-voltage safety, electric shocks and system design rules are covered. (author)

  18. Technological Aspects: High Voltage

    CERN Document Server

    Faircloth, D.C.

    2013-12-16

    This paper covers the theory and technological aspects of high-voltage design for ion sources. Electric field strengths are critical to understanding high-voltage breakdown. The equations governing electric fields and the techniques to solve them are discussed. The fundamental physics of high-voltage breakdown and electrical discharges are outlined. Different types of electrical discharges are catalogued and their behaviour in environments ranging from air to vacuum are detailed. The importance of surfaces is discussed. The principles of designing electrodes and insulators are introduced. The use of high-voltage platforms and their relation to system design are discussed. The use of commercially available high-voltage technology such as connectors, feedthroughs and cables are considered. Different power supply technologies and their procurement are briefly outlined. High-voltage safety, electric shocks and system design rules are covered.

  19. Stray voltage mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Jamali, B.; Piercy, R.; Dick, P. [Kinetrics Inc., Toronto, ON (Canada). Transmission and Distribution Technologies

    2008-04-09

    This report discussed issues related to farm stray voltage and evaluated mitigation strategies and costs for limiting voltage to farms. A 3-phase, 3-wire system with no neutral ground was used throughout North America before the 1930s. Transformers were connected phase to phase without any electrical connection between the primary and secondary sides of the transformers. Distribution voltage levels were then increased and multi-grounded neutral wires were added. The earth now forms a parallel return path for the neutral current that allows part of the neutral current to flow continuously through the earth. The arrangement is responsible for causing stray voltage. Stray voltage causes uneven milk production, increased incidences of mastitis, and can create a reluctance to drink water amongst cows when stray voltages are present. Off-farm sources of stray voltage include phase unbalances, undersized neutral wire, and high resistance splices on the neutral wire. Mitigation strategies for reducing stray voltage include phase balancing; conversion from single to 3-phase; increasing distribution voltage levels, and changing pole configurations. 22 refs., 5 tabs., 13 figs.

  20. High voltage engineering

    CERN Document Server

    Rizk, Farouk AM

    2014-01-01

    Inspired by a new revival of worldwide interest in extra-high-voltage (EHV) and ultra-high-voltage (UHV) transmission, High Voltage Engineering merges the latest research with the extensive experience of the best in the field to deliver a comprehensive treatment of electrical insulation systems for the next generation of utility engineers and electric power professionals. The book offers extensive coverage of the physical basis of high-voltage engineering, from insulation stress and strength to lightning attachment and protection and beyond. Presenting information critical to the design, selec

  1. High voltage test techniques

    CERN Document Server

    Kind, Dieter

    2001-01-01

    The second edition of High Voltage Test Techniques has been completely revised. The present revision takes into account the latest international developments in High Voltage and Measurement technology, making it an essential reference for engineers in the testing field.High Voltage Technology belongs to the traditional area of Electrical Engineering. However, this is not to say that the area has stood still. New insulating materials, computing methods and voltage levels repeatedly pose new problems or open up methods of solution; electromagnetic compatibility (EMC) or components and systems al

  2. Heat conduction through geological mattresses from cells storing mean activity and long life nuclear wastes

    International Nuclear Information System (INIS)

    Lajoie, D.; Raffourt, C.; Wendling, J.

    2010-01-01

    Document available in extended abstract form only. ANDRA ordered in 2008 a campaign of numerical simulations to assess the efficiency of the ventilation system designed for cells storing mean activity and long life nuclear wastes. Numerical models were performed by ACRIIN as research engineering office. The main objectives were to assess the risks of atmospheric explosions due to high rate of hydrogen and to determine the efficiency of the system to evacuate released heat from storage packages. Further calculations have been carried out to evaluate temperature gradients in the surrounding geological medium. Three-dimensional numerical models of a reference cell were built to simulate the air flow injected at the cell entrance and retrieved and the other extremity. The reference case is based on a cell full of storage packages, with rows and columns of packages methodically ordered. Analytic and numerical calculations have been performed introducing progressively each complex physical phenomenon in order to dissociate origins of transport of released mass or heat. Three kinds of flows have been physically distinguished: 1) Ventilation in a cell with storage package that are thermally inert, i.e. no heat release, but with hydrogen release. 2) Flow in a cell with storage packages that emit heat and warm the injected air, supposing that no heat were lost towards the surrounding concrete walls of the cell. 3) Air Flow warmed by the storage packages with heat losses towards concrete walls and geological medium. Simulations with absence of thermal effects allowed the knowledge of main topics of the ventilation air flows that may be synthesized as follows: - Flows infiltrate clearances between piles and rows of storage packages. Such apertures are a few centimetres wide. The flow is disorganised between the first rows, with distribution in both transversal and longitudinal directions. After a few tens of rows, the flow reaches its hydraulic equilibrium, with a nearly pure

  3. [Redesign of the Spacesuit Long Life Battery and the Personal Life Support System Battery

    Science.gov (United States)

    Scharf, Stephanie

    2015-01-01

    This fall I was working on two different projects that culminated into a redesign of the spacesuit LLB (long life battery). I also did some work on the PLSS (personal life support system) battery with EC. My first project was redlining the work instruction for completing DPAs (destructive physical analysis) on battery cells in the department. The purpose of this document is to create a standard process and ensure that the data in the same way no matter who carries out the analysis. I observed three DPAs, conducted one with help, and conducted two on my own all while taking notes on the procedure. These notes were used to write the final work instruction that will become is the department standard. My second project continued the work of the summer co-op before me. I was testing aluminum heat sinks for their ability to provide good thermal conduction and structural support during a thermal runaway event. The heat sinks were designed by the summer intern but there was not much time for testing before he left. We ran tests with a heater on the bottom of a trigger cell to try to drive thermal runaway and ensure that it will not propagate to adjacent cells. We also ran heat-to-vent tests in an oven to see if the assembly provided structural support and prevented sidewall rupture during thermal runaway. These tests were carried out at ESTA (energy systems test area) and are providing very promising results that safe, high performing (greater than 180 Wh/kg) designs are possible. My main project was a redesign of the LLB battery. Another summer intern did some testing and concluded that there was no simple fix to mitigate thermal runaway propagation hazards in the current design. The only option was a clean sheet redesign of the battery. I was given a volume and ideal energy density and the rest of the design was up to me. First, I created new heat sink banks in Creo using the information gathered in the metal heat sink tests from the summer intern. After this, I made

  4. Long Life Nickel Electrodes for Nickel-Hydrogen Cells: Fiber Substrates Nickel Electrodes

    Science.gov (United States)

    Rogers, Howard H.

    2000-01-01

    Samples of nickel fiber mat electrodes were investigated over a wide range of fiber diameters, electrode thickness, porosity and active material loading levels. Thickness' were 0.040, 0.060 and 0.080 inches for the plaque: fiber diameters were primarily 2, 4, and 8 micron and porosity was 85, 90, and 95%. Capacities of 3.5 in. diameter electrodes were determined in the flooded condition with both 26 and 31% potassium hydroxide solution. These capacity tests indicated that the highest capacities per unit weight were obtained at the 90% porosity level with a 4 micron diameter fiber plaque. It appeared that the thinner electrodes had somewhat better performance, consistent with sintered electrode history. Limited testing with two-positive-electrode boiler plate cells was also carried out. Considerable difficulty with constructing the cells was encountered with short circuits the major problem. Nevertheless, four cells were tested. The cell with 95% porosity electrodes failed during conditioning cycling due to high voltage during charge. Discharge showed that this cell had lost nearly all of its capacity. The other three cells after 20 conditioning cycles showed capacities consistent with the flooded capacities of the electrodes. Positive electrodes made from fiber substrates may well show a weight advantage of standard sintered electrodes, but need considerably more work to prove this statement. A major problem to be investigated is the lower strength of the substrate compared to standard sintered electrodes. Problems with welding of leads were significant and implications that the electrodes would expand more than sintered electrodes need to be investigated. Loading levels were lower than had been expected based on sintered electrode experiences and the lower loading led to lower capacity values. However, lower loading causes less expansion and contraction during cycling so that stress on the substrate is reduced.

  5. Laboratory Connections--Gas Monitoring Transducers Part III: Combustible Gas Sensors.

    Science.gov (United States)

    Powers, Michael H.; Dahman, Doug

    1989-01-01

    Describes an interface that uses semiconductor metal oxides to detect low gas concentrations. Notes the detector has long life, high stability, good reproducibility, low cost, and is able to convert the gas concentration to an electrical signal with a simple circuit. Theory, schematic, and applications are provided. (MVL)

  6. Orbit and geometry constraints on the design and operation of a long-life SIRTF mission. [Shuttle Infrared Telescope Facility

    Science.gov (United States)

    Jackson, R. W.

    1984-01-01

    For a long-life SIRTF mission, the ability of the telescope to observe targets everywhere in the sky is an important requirement. For low-inclination orbits, a telescope aperture shade must be designed for Sun and Earth Limb avoidance angles of 50 deg to 60 deg to prevent unwanted radiation from entering the telescope. The minimum orbit inclination depends on the Earth Limb avoidance angle. About 30 percent of the sky will be prohibited for observations during any day in orbit, with about 100 days in orbit required to observe the entire sky.

  7. Small Displacement, Long Life On-Orbit Compressor Design and Fabrication

    Science.gov (United States)

    Gerlach, C. R.; Schroeder, E. C.; Deffenbaugh, D. D.; Masetta, J. P.

    1989-01-01

    The focus is the generation of technology and fabrication of prototype hardware applicable to seven Space Station compressor system applications. The compressors are of the single acting reciprocating piston type and, in general, may be termed miniature in size compared with normal commercially available equipment. The initial technology development is focused on improved valve designs, and the control of pulsations and heating effects in order to increase compressor efficiency and reduce cycle temperatures, thus permitting significantly increased stage pressure ratios. The initial test compressor was successfully operated at pressure ratios of up to 50:1, and this significant extension of allowable pressure ratio will result in a reduction of the number of required stages and, hence, total hardware thereby reducing system weight and volume. These experiments have also identified the need to employ low shaft speeds, on the order of 250 to 500 rpm, to enhance heat transfer and increase life. The prototype compressor currently being designed, is to be driven by a low-speed brushless dc motor sealed in a case common to the compressor drive mechanism case. The compressor and motor case will communicate with stage suction pressure so that any minor gas leakage past the piston rings will be returned to the suction. Emphasis in this prototype design is being placed on simplicity, durability, commonality of components, and high efficiency.

  8. based dynamic voltage restorer

    African Journals Online (AJOL)

    HOD

    operation due to presence of increased use of nonlinear loads (computers, microcontrollers ... simulations of a dynamic voltage restorer (DVR) was achieved using MATLAB/Simulink. ..... using Discrete PWM generator, then the IGBT inverter.

  9. Analysis on small long life reactor using thorium fuel for water cooled and metal cooled reactor types

    International Nuclear Information System (INIS)

    Permana, Sidik

    2009-01-01

    Long-life reactor operation can be adopted for some special purposes which have been proposed by IAEA as the small and medium reactor (SMR) program. Thermal reactor and fast reactor types can be used for SMR and in addition to that program the utilization of thorium fuel as one of the candidate as a 'partner' fuel with uranium fuel which can be considered for optimizing the nuclear fuel utilization as well as recycling spent fuel. Fissile U-233 as the main fissile material for thorium fuel shows higher eta-value for wider energy range compared with other fissile materials of U-235 and Pu-239. However, it less than Pu-239 for fast energy region, but it still shows high eta-value. This eta-value gives the reactor has higher capability for obtaining breeding condition or high conversion capability. In the present study, the comparative analysis on small long life reactor fueled by thorium for different reactor types (water cooled and metal cooled reactor types). Light water and heavy water have been used as representative of water-cooled reactor types, and for liquid metal-cooled reactor types, sodium-cooled and lead-bismuth-cooled have been adopted. Core blanket arrangement as general design configuration, has been adopted which consist of inner blanket region fueled by thorium oxide, and two core regions (inner and out regions) fueled by fissile U-233 and thorium oxide with different percentages of fissile content. SRAC-CITATION and JENDL-33 have been used as core optimization analysis and nuclear data library for this analysis. Reactor operation time can reaches more than 10 years operation without refueling and shuffling for different reactor types and several power outputs. As can be expected, liquid metal cooled reactor types can be used more effective for obtaining long life reactor with higher burnup, higher power density, higher breeding capability and lower excess reactivity compared with water-cooled reactors. Water cooled obtains long life core operation

  10. High voltage engineering fundamentals

    CERN Document Server

    Kuffel, E; Hammond, P

    1984-01-01

    Provides a comprehensive treatment of high voltage engineering fundamentals at the introductory and intermediate levels. It covers: techniques used for generation and measurement of high direct, alternating and surge voltages for general application in industrial testing and selected special examples found in basic research; analytical and numerical calculation of electrostatic fields in simple practical insulation system; basic ionisation and decay processes in gases and breakdown mechanisms of gaseous, liquid and solid dielectrics; partial discharges and modern discharge detectors; and over

  11. Low-voltage gyrotrons

    International Nuclear Information System (INIS)

    Glyavin, M. Yu.; Zavolskiy, N. A.; Sedov, A. S.; Nusinovich, G. S.

    2013-01-01

    For a long time, the gyrotrons were primarily developed for electron cyclotron heating and current drive of plasmas in controlled fusion reactors where a multi-megawatt, quasi-continuous millimeter-wave power is required. In addition to this important application, there are other applications (and their number increases with time) which do not require a very high power level, but such issues as the ability to operate at low voltages and have compact devices are very important. For example, gyrotrons are of interest for a dynamic nuclear polarization, which improves the sensitivity of the nuclear magnetic resonance spectroscopy. In this paper, some issues important for operation of gyrotrons driven by low-voltage electron beams are analyzed. An emphasis is made on the efficiency of low-voltage gyrotron operation at the fundamental and higher cyclotron harmonics. These efficiencies calculated with the account for ohmic losses were, first, determined in the framework of the generalized gyrotron theory based on the cold-cavity approximation. Then, more accurate, self-consistent calculations for the fundamental and second harmonic low-voltage sub-THz gyrotron designs were carried out. Results of these calculations are presented and discussed. It is shown that operation of the fundamental and second harmonic gyrotrons with noticeable efficiencies is possible even at voltages as low as 5–10 kV. Even the third harmonic gyrotrons can operate at voltages about 15 kV, albeit with rather low efficiency (1%–2% in the submillimeter wavelength region).

  12. Device for monitoring cell voltage

    Science.gov (United States)

    Doepke, Matthias [Garbsen, DE; Eisermann, Henning [Edermissen, DE

    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.

  13. Report of results and progress research (1982-1984) total research on long life radioactive waste management

    International Nuclear Information System (INIS)

    1985-03-01

    The specific research ''Synthetic research on long life radioactive waste management'' has been advanced in the Research Center for Nuclear Energy, University of Tokyo, for three years since 1982. This research was roughly divided into material science, biology and process engineering, and the research has been advanced according to 14 subthemes by the cooperation of the researchers in wide fields in the university. In this report, the report of the progress of research and the data on the results of researche from fiscal year 1982 to 1984 are summarized. The title of research, organization, the persons in charge, the period of research, the title of report, the objective, contents, state of progress, results obtained in 1984 and results obtained during three years of 5 material group papers, 7 process group papers and 4 biology group papers are given. (Kako, I.)

  14. Candidate gene resequencing to identify rare, pedigree-specific variants influencing healthy aging phenotypes in the long life family study

    DEFF Research Database (Denmark)

    Druley, Todd E; Wang, Lihua; Lin, Shiow J

    2016-01-01

    from six pedigrees. OBFC1 (chromosome 10) is involved in telomere maintenance, and falls within a linkage peak recently reported from an analysis of telomere length in LLFS families. Two different algorithms for single gene associations identified three genes with an enrichment of variation......BACKGROUND: The Long Life Family Study (LLFS) is an international study to identify the genetic components of various healthy aging phenotypes. We hypothesized that pedigree-specific rare variants at longevity-associated genes could have a similar functional impact on healthy phenotypes. METHODS......: We performed custom hybridization capture sequencing to identify the functional variants in 464 candidate genes for longevity or the major diseases of aging in 615 pedigrees (4,953 individuals) from the LLFS, using a multiplexed, custom hybridization capture. Variants were analyzed individually...

  15. Carbon tiles as spectral-shifter for long-life liquid blanket in LHD-type reactor FFHR

    International Nuclear Information System (INIS)

    Sagara, A.; Imagawa, S.; Tanaka, T.; Muroga, T.; Kubota, Y.; Dolan, T.; Hashizume, H.; Kunugi, T.; Fukada, S.; Shimizu, A.; Terai, T.; Mitarai, O.

    2006-01-01

    In terms of engineering feasibility for long-life Flibe blanket in LHD-type reactor FFHR, the Spectral-shifter and Tritium breeder Blanket (STB) concept is evaluated by taking neutron irradiation effects into account under system integration such as Flibe cooling and components replacement. FEM calculations for the neutron wall loading of 1.5 MW/m 2 show that the temperature of the STB armor tile can be kept below 2000 K by optimizing the first metal wall thickness. The heat load experiment on the STB armor mockup confirms feasibility of the temperature control and mechanical joining. Degradation of STB armor tiles due to neutron irradiation requires replacement of them every few years by means of remote handling 'screw coasters' using helical winding, where the replaced tiles are low level wastes. Although the STB concept is feasible within nuclear and thermal properties, more detailed structural optimization is needed including the mechanical and chemical properties

  16. Genomewide Association Scan of a Mortality Associated Endophenotype for a Long and Healthy Life in the Long Life Family Study.

    Science.gov (United States)

    Singh, Jatinder; Minster, Ryan L; Schupf, Nicole; Kraja, Aldi; Liu, YongMei; Christensen, Kaare; Newman, Anne B; Kammerer, Candace M

    2017-10-01

    Identification of genes or fundamental biological pathways that regulate aging phenotypes and longevity could lead to possible interventions to increase healthy longevity. Using data from the Long Life Family Study, we performed genomewide association analyses on an endophenotype construct, LF1, comprising a linear combination of traits across health domains. LF1 primarily reflected traits from the pulmonary and physical activity domains. We detected a significant association between LF1 and a locus on chromosome 10p15 (p-value = 4.65 × 10-8) and suggestive evidence (p-value physical function domains may be located on chromosome 1p13 near the NBPF6 locus. Further investigation of this possible locus and other suggestive loci may reveal novel biological pathways that influence healthy aging. © The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. An independent method for data selection of long-life radionuclides (actinides and fission products) in the geosphere

    International Nuclear Information System (INIS)

    Henry, M.; Merceron, T.

    1994-01-01

    An independent method for data selection of long-life radio-nuclides based on the electronegativity equalization principle is proposed to predict the speciation of metal cations as a function of the solution pH. Hydrolysis, condensation and complexation reactions of metal cations in aqueous media are, by this simple model, unified and can be analyzed in terms of electronegativities, oxidation states and coordination numbers with a specific PC software. This paper describes the thermodynamical basis and the underlying concepts of the model in relation to aqueous actinide chemistry of elements such as U and Tc. It is then shown that the model could provide a complementary approach to existing softwares based on thermodynamic data bases allowing to make intelligent and reasonnable choices for the various complexes to consider in complex geochemical codes. (orig.)

  18. Multi-physics design and analyses of long life reactors for lunar outposts

    Science.gov (United States)

    Schriener, Timothy M.

    event of a launch abort accident. Increasing the amount of fuel in the reactor core, and hence its operational life, would be possible by launching the reactor unfueled and fueling it on the Moon. Such a reactor would, thus, not be subject to launch criticality safety requirements. However, loading the reactor with fuel on the Moon presents a challenge, requiring special designs of the core and the fuel elements, which lend themselves to fueling on the lunar surface. This research investigates examples of both a solid core reactor that would be fueled at launch as well as an advanced concept which could be fueled on the Moon. Increasing the operational life of a reactor fueled at launch is exercised for the NaK-78 cooled Sectored Compact Reactor (SCoRe). A multi-physics design and analyses methodology is developed which iteratively couples together detailed Monte Carlo neutronics simulations with 3-D Computational Fluid Dynamics (CFD) and thermal-hydraulics analyses. Using this methodology the operational life of this compact, fast spectrum reactor is increased by reconfiguring the core geometry to reduce neutron leakage and parasitic absorption, for the same amount of HEU in the core, and meeting launch safety requirements. The multi-physics analyses determine the impacts of the various design changes on the reactor's neutronics and thermal-hydraulics performance. The option of increasing the operational life of a reactor by loading it on the Moon is exercised for the Pellet Bed Reactor (PeBR). The PeBR uses spherical fuel pellets and is cooled by He-Xe gas, allowing the reactor core to be loaded with fuel pellets and charged with working fluid on the lunar surface. The performed neutronics analyses ensure the PeBR design achieves a long operational life, and develops safe launch canister designs to transport the spherical fuel pellets to the lunar surface. The research also investigates loading the PeBR core with fuel pellets on the Moon using a transient Discrete

  19. High frequency breakdown voltage

    International Nuclear Information System (INIS)

    Chu, Thanh Duy.

    1992-03-01

    This report contains information about the effect of frequency on the breakdown voltage of an air gap at standard pressure and temperature, 76 mm Hg and O degrees C, respectively. The frequencies of interest are 47 MHz and 60 MHz. Additionally, the breakdown in vacuum is briefly considered. The breakdown mechanism is explained on the basis of collision and ionization. The presence of the positive ions produced by ionization enhances the field in the gap, and thus determines the breakdown. When a low-frequency voltage is applied across the gap, the breakdown mechanism is the same as that caused by the DC or static voltage. However, when the frequency exceeds the first critical value f c , the positive ions are trapped in the gap, increasing the field considerably. This makes the breakdown occur earlier; in other words, the breakdown voltage is lowered. As the frequency increases two decades or more, the second critical frequency, f ce , is reached. This time the electrons start being trapped in the gap. Those electrons that travel multiple times across the gap before reaching the positive electrode result in an enormous number of electrons and positive ions being present in the gap. The result is a further decrease of the breakdown voltage. However, increasing the frequency does not decrease the breakdown voltage correspondingly. In fact, the associated breakdown field intensity is almost constant (about 29 kV/cm).The reason is that the recombination rate increases and counterbalances the production rate, thus reducing the effect of the positive ions' concentration in the gap. The theory of collision and ionization does not apply to the breakdown in vacuum. It seems that the breakdown in vacuum is primarily determined by the irregularities on the surfaces of the electrodes. Therefore, the effect of frequency on the breakdown, if any, is of secondary importance

  20. Switching phenomena in high-voltage circuit breakers

    International Nuclear Information System (INIS)

    Nakanishi, K.

    1991-01-01

    The topics covered in this book include: general problems concerning current interruption, the physical arc model, and miscellaneous types of modern switching apparatus, such as gas circuit breakers, gas-insulated switch-gear, vacuum circuit breakers and high-voltage direct-current circuit breakers

  1. Digital voltage discriminator

    International Nuclear Information System (INIS)

    Zhou Zhicheng

    1992-01-01

    A digital voltage discriminator is described, which is synthesized by digital comparator and ADC. The threshold is program controllable with high stability. Digital region of confusion is approximately equal to 1.5 LSB. This discriminator has a single channel analyzer function model with channel width of 1.5 LSB

  2. Geomagnetism and Induced Voltage

    Science.gov (United States)

    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…

  3. Mitigation of Unbalanced Voltage Sags and Voltage Unbalance in CIGRE Low Voltage Distribution Network

    DEFF Research Database (Denmark)

    Mustafa, Ghullam; Bak-Jensen, Birgitte; Mahat, Pukar

    2013-01-01

    Any problem with voltage in a power network is undesirable as it aggravates the quality of the power. Power electronic devices such as Voltage Source Converter (VSC) based Static Synchronous Compensator (STATCOM) etc. can be used to mitigate the voltage problems in the distribution system...... to unbalanced faults. The compensation of unbalanced voltage sags and voltage unbalance in the CIGRE distribution network is done by using the four STATCOM compensators already existing in the test grid. The simulations are carried out in DIgSILENT power factory software version 15.0........ The voltage problems dealt with in this paper are to show how to mitigate unbalanced voltage sags and voltage unbalance in the CIGRE Low Voltage (LV) test network and net-works like this. The voltage unbalances, for the tested cases in the CIGRE LV test network are mainly due to single phase loads and due...

  4. DC-link Voltage Control to Compensate Voltage Deviation for PV–BESSs Integrated System in Low-Voltage (LV Networks

    Directory of Open Access Journals (Sweden)

    Lee Gyu-sub

    2016-01-01

    Full Text Available The exhaustion of fossil fuel and the greenhouse gas emission are one of the most significant energy and environmental issues, respectively. Photovoltaic (PV generators and battery energy storage systems (BESSs have been significantly increased for recent years. The BESSs are mainly used for smoothing active power fluctuation of the PV. In this paper, PV–BESSs integration of two DC/DC converters and one AC/DC converter is investigated and DC-link voltage control to compensate the AC voltage deviation is proposed for the PV‒BESS system in low-voltage (LV networks.

  5. Mitigation of Voltage Sags in CIGRE Low Voltage Distribution Network

    DEFF Research Database (Denmark)

    Mustafa, Ghullam; Bak-Jensen, Birgitte; Mahat, Pukar

    2013-01-01

    Any problem in voltage in a power network is undesirable as it aggravates the quality of the power. Power electronic devices such as Voltage Source Converter (VSC) based Static Synchronous Compensator (STATCOM), Dynamic Voltage Restorer (DVR) etc. are commonly used for the mitigation of voltage p....... The compensation of voltage sags in the different parts of CIGRE distribution network is done by using the four STATCOM compensators already existing in the test grid. The simulations are carried out in DIgSILENT power factory software version 15.0.......Any problem in voltage in a power network is undesirable as it aggravates the quality of the power. Power electronic devices such as Voltage Source Converter (VSC) based Static Synchronous Compensator (STATCOM), Dynamic Voltage Restorer (DVR) etc. are commonly used for the mitigation of voltage...... problems in the distribution system. The voltage problems dealt with in this paper are to show how to mitigate voltage sags in the CIGRE Low Voltage (LV) test network and networks like this. The voltage sags, for the tested cases in the CIGRE LV test network are mainly due to three phase faults...

  6. Toward developing long-life water quality sensors for the ISS using planar REDOX and conductivity sensors

    Science.gov (United States)

    Buehler, M. G.; Kuhlman, G. M.; Keymeulen, D.; Myung, N.; Kounaves, S. P.

    2003-01-01

    REDOX and conductivity sensors are metal electrodes that are used to detect ionic species in solution by measuring the electrochemical cell current as the voltage is scanned. This paper describes the construction of the sensors, the potentiostat electronics, the measurement methodology, and applications to water quality measurements.

  7. High Voltage Charge Pump

    KAUST Repository

    Emira, Ahmed A.; Abdelghany, Mohamed A.; Elsayed, Mohannad Yomn; Elshurafa, Amro M; Salama, Khaled N.

    2014-01-01

    Various embodiments of a high voltage charge pump are described. One embodiment is a charge pump circuit that comprises a plurality of switching stages each including a clock input, a clock input inverse, a clock output, and a clock output inverse. The circuit further comprises a plurality of pumping capacitors, wherein one or more pumping capacitors are coupled to a corresponding switching stage. The circuit also comprises a maximum selection circuit coupled to a last switching stage among the plurality of switching stages, the maximum selection circuit configured to filter noise on the output clock and the output clock inverse of the last switching stage, the maximum selection circuit further configured to generate a DC output voltage based on the output clock and the output clock inverse of the last switching stage.

  8. High Voltage Charge Pump

    KAUST Repository

    Emira, Ahmed A.

    2014-10-09

    Various embodiments of a high voltage charge pump are described. One embodiment is a charge pump circuit that comprises a plurality of switching stages each including a clock input, a clock input inverse, a clock output, and a clock output inverse. The circuit further comprises a plurality of pumping capacitors, wherein one or more pumping capacitors are coupled to a corresponding switching stage. The circuit also comprises a maximum selection circuit coupled to a last switching stage among the plurality of switching stages, the maximum selection circuit configured to filter noise on the output clock and the output clock inverse of the last switching stage, the maximum selection circuit further configured to generate a DC output voltage based on the output clock and the output clock inverse of the last switching stage.

  9. High Voltage Seismic Generator

    Science.gov (United States)

    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

  10. Increased voltage photovoltaic cell

    Science.gov (United States)

    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.

  11. Utilization of Minor Actinides as a Fuel Component for Ultra-Long Life VHTR Configurations: Designs, Advantages and Limitations

    International Nuclear Information System (INIS)

    Tsvetkov, Pavel V.

    2009-01-01

    This project assessed the advantages and limitations of using minor actinides as a fuel component to achieve ultra-long life Very High Temperature Reactor (VHTR) configurations. Researchers considered and compared the capabilities of pebble-bed and prismatic core designs with advanced actinide fuels to achieve ultra-long operation without refueling. Since both core designs permit flexibility in component configuration, fuel utilization, and fuel management, it is possible to improve fissile properties of minor actinides by neutron spectrum shifting through configuration adjustments. The project studied advanced actinide fuels, which could reduce the long-term radio-toxicity and heat load of high-level waste sent to a geologic repository and enable recovery of the energy contained in spent fuel. The ultra-long core life autonomous approach may reduce the technical need for additional repositories and is capable to improve marketability of the Generation IV VHTR by allowing worldwide deployment, including remote regions and regions with limited industrial resources. Utilization of minor actinides in nuclear reactors facilitates developments of new fuel cycles towards sustainable nuclear energy scenarios.

  12. Families enriched for exceptional longevity also have increased health span: Findings from the Long Life Family Study

    Directory of Open Access Journals (Sweden)

    Paola eSebastiani

    2013-09-01

    Full Text Available Hypothesizing that members of families enriched for longevity delay morbidity compared to population controls and approximate the health-span of centenarians, we compared the health spans of older generation subjects of the Long Life Family Study (LLFS to controls without family history of longevity and to centenarians of the New England Centenarian Study (NECS using Bayesian parametric survival analysis. We estimated hazard ratios, the ages at which specific percentiles of subjects had onsets of diseases, and the gain of years of disease-free survival in the different cohorts compared to referent controls. Compared to controls, LLFS subjects had lower hazards for cancer, cardiovascular disease, severe dementia, diabetes, hypertension, osteoporosis and stroke. The age at which 20% of the LLFS siblings and probands had one or more age-related diseases was approximately 10 years later than NECS controls. While female NECS controls generally delayed the onset of age-related diseases compared with males controls, these gender differences became much less in the older generation of the LLFS and disappeared amongst the centenarians of the NECS. The analyses demonstrate extended health-span in the older subjects of the LLFS and suggest that this aging cohort provides an important resource to discover genetic and environmental factors that promote prolonged health-span in addition to longer life-span.

  13. Utilization of Minor Actinides as a Fuel Component for Ultra-Long Life Bhr Configurations: Designs, Advantages and Limitations

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Pavel V. Tsvetkov

    2009-05-20

    This project assessed the advantages and limitations of using minor actinides as a fuel component to achieve ultra-long life Very High Temperature Reactor (VHTR) configurations. Researchers considered and compared the capabilities of pebble-bed and prismatic core designs with advanced actinide fuels to achieve ultra-long operation without refueling. Since both core designs permit flexibility in component configuration, fuel utilization, and fuel management, it is possible to improve fissile properties of minor actinides by neutron spectrum shifting through configuration adjustments. The project studied advanced actinide fuels, which could reduce the long-term radio-toxicity and heat load of high-level waste sent to a geologic repository and enable recovery of the energy contained in spent fuel. The ultra-long core life autonomous approach may reduce the technical need for additional repositories and is capable to improve marketability of the Generation IV VHTR by allowing worldwide deployment, including remote regions and regions with limited industrial resources. Utilization of minor actinides in nuclear reactors facilitates developments of new fuel cycles towards sustainable nuclear energy scenarios.

  14. Heart rate, multiple body temperature, long-range and long-life telemetry system for free-ranging animals

    Science.gov (United States)

    Lund, G. F.; Westbrook, R. M.; Fryer, T. B.

    1980-01-01

    The design details and rationale for a versatile, long-range, long-life telemetry data acquisition system for heart rates and body temperatures at multiple locations from free-ranging animals are presented. The design comprises an implantable transmitter for short to medium range transmission, a receiver retransmitter collar to be worn for long-range transmission, and a signal conditioner interface circuit to assist in signal discrimination and demodulation of receiver or tape-recorded audio outputs. Implanted electrodes are used to obtain an ECG, from which R-wave characteristics are selected to trigger a short RF pulse. Pulses carrying heart rate information are interrupted periodically by a series of pulse interval modulated RF pulses conveying temperature information sensed at desired locations by thermistors. Pulse duration and pulse sequencing are used to discriminate between heart rate and temperature pulses as well as radio frequency interference. The implanted transmitter may be used alone for medium and short-range tracking, or with a receiver-transmitter collar that employs commercial tracking equipment for transmissions of up to 12 km. A system prototype has been tested on a dog.

  15. Study on core radius minimization for long life Pb-Bi cooled CANDLE burnup scheme based fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    Afifah, Maryam, E-mail: maryam.afifah210692@gmail.com; Su’ud, Zaki [Nuclear Research Group, FMIPA, Bandung Institute of Technology Jl. Ganesha 10, Bandung 40132 (Indonesia); Miura, Ryosuke; Takaki, Naoyuki [Department of Nuclear Safety Engineering, Tokyo City University 1-28-1 Tamazutsumi, Setagaya, Tokyo 158-8557 (Japan); Sekimoto, H. [Emerritus Prof. of Research Laboratory for Nuclear Reactors, Tokyo Inst. of Technology (Japan)

    2015-09-30

    Fast Breeder Reactor had been interested to be developed over the world because it inexhaustible source energy, one of those is CANDLE reactor which is have strategy in burn-up scheme, need not control roads for control burn-up, have a constant core characteristics during energy production and don’t need fuel shuffling. The calculation was made by basic reactor analysis which use Sodium coolant geometry core parameter as a reference core to study on minimum core reactor radius of CANDLE for long life Pb-Bi cooled, also want to perform pure coolant effect comparison between LBE and sodium in a same geometry design. The result show that the minimum core radius of Lead Bismuth cooled CANDLE is 100 cm and 500 MWth thermal output. Lead-Bismuth coolant for CANDLE reactor enable to reduce much reactor size and have a better void coefficient than Sodium cooled as the most coolant for FBR, then we will have a good point in safety analysis.

  16. Suppressing voltage transients in high voltage power supplies

    International Nuclear Information System (INIS)

    Lickel, K.F.; Stonebank, R.

    1979-01-01

    A high voltage power supply for an X-ray tubes includes voltage adjusting means, a high voltage transformer, switch means connected to make and interrupt the primary current of the transformer, and over-voltage suppression means to suppress the voltage transient produced when the current is switched on. In order to reduce the power losses in the suppression means, an impedance is connected in the transformer primary circuit on operation of the switch means and is subsequently short-circuited by a switch controlled by a timer after a period which is automatically adjusted to the duration of the transient overvoltage. (U.K.)

  17. Benchmarking of Voltage Sag Generators

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede; Zou, Zhixiang

    2012-01-01

    The increased penetration of renewable energy systems, like photovoltaic and wind power systems, rises the concern about the power quality and stability of the utility grid. Some regulations for Low Voltage Ride-Through (LVRT) for medium voltage or high voltage applications, are coming into force...

  18. Charge-pump voltage converter

    Science.gov (United States)

    Brainard, John P [Albuquerque, NM; Christenson, Todd R [Albuquerque, NM

    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.

  19. Transient voltage sharing in series-coupled high voltage switches

    Directory of Open Access Journals (Sweden)

    Editorial Office

    1992-07-01

    Full Text Available For switching voltages in excess of the maximum blocking voltage of a switching element (for example, thyristor, MOSFET or bipolar transistor such elements are often coupled in series - and additional circuitry has to be provided to ensure equal voltage sharing. Between each such series element and system ground there is a certain parasitic capacitance that may draw a significant current during high-speed voltage transients. The "open" switch is modelled as a ladder network. Analy­sis reveals an exponential progression in the distribution of the applied voltage across the elements. Overstressing thus oc­curs in some of the elements at levels of the total voltage that are significantly below the design value. This difficulty is overcome by grading the voltage sharing circuitry, coupled in parallel with each element, in a prescribed manner, as set out here.

  20. Induced voltages in metallic pipelines near power transmission lines

    International Nuclear Information System (INIS)

    Grcev, Leonid; Jankov, Voislav; Filiposki, Velimir

    2002-01-01

    With the continuous development of the electric power system and the pipeline networks used to convey oil or natural gas, cases of close proximity of high voltage structures and metallic pipelines become more and more frequent. Accordingly there is a growing concern about possible hazards resulting from voltages induced in the metallic pipelines by magnetic coupling with nearby power transmission lines. This paper presents a methodology for computation of the induced voltages in buried isolated metallic pipelines. A practical example of computation is also presented. (Author)

  1. Submission of the national commission of the public debate on the options concerning the long life high and medium activity radioactive wastes management

    International Nuclear Information System (INIS)

    2006-01-01

    This document deals with the presentation of a public debate on the radioactive wastes management and the opportunities of its organization. It presents successively the long life high and medium activity radioactive wastes, the today radioactive wastes management policy and some questions and topics which could be discussed during the debate. (A.L.B.)

  2. Coordinated Voltage Control of Distributed PV Inverters for Voltage Regulation in Low Voltage Distribution Networks

    DEFF Research Database (Denmark)

    Nainar, Karthikeyan; Pokhrel, Basanta Raj; Pillai, Jayakrishnan Radhakrishna

    2017-01-01

    This paper reviews and analyzes the existing voltage control methods of distributed solar PV inverters to improve the voltage regulation and thereby the hosting capacity of a low-voltage distribution network. A novel coordinated voltage control method is proposed based on voltage sensitivity...... optimization. The proposed method is used to calculate the voltage bands and droop settings of PV inverters at each node by the supervisory controller. The local controller of each PV inverter implements the volt/var control and if necessary, the active power curtailment as per the received settings and based...... on measured local voltages. The advantage of the proposed method is that the calculated reactive power and active power droop settings enable fair contribution of the PV inverters at each node to the voltage regulation. Simulation studies are conducted using DigSilent Power factory software on a simplified...

  3. Sensing voltage across lipid membranes

    Science.gov (United States)

    Swartz, Kenton J.

    2009-01-01

    The detection of electrical potentials across lipid bilayers by specialized membrane proteins is required for many fundamental cellular processes such as the generation and propagation of nerve impulses. These membrane proteins possess modular voltage-sensing domains, a notable example being the S1-S4 domains of voltage-activated ion channels. Ground-breaking structural studies on these domains explain how voltage sensors are designed and reveal important interactions with the surrounding lipid membrane. Although further structures are needed to fully understand the conformational changes that occur during voltage sensing, the available data help to frame several key concepts that are fundamental to the mechanism of voltage sensing. PMID:19092925

  4. Heat-pump performance: voltage dip/sag, under-voltage and over-voltage

    Directory of Open Access Journals (Sweden)

    William J.B. Heffernan

    2014-12-01

    Full Text Available Reverse cycle air-source heat-pumps are an increasingly significant load in New Zealand and in many other countries. This has raised concern over the impact wide-spread use of heat-pumps may have on the grid. The characteristics of the loads connected to the power system are changing because of heat-pumps. Their performance during under-voltage events such as voltage dips has the potential to compound the event and possibly cause voltage collapse. In this study, results from testing six heat-pumps are presented to assess their performance at various voltages and hence their impact on voltage stability.

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

    International Nuclear Information System (INIS)

    Yang Jiaxiang; Lan Sheng; Xu Zuoming

    2008-01-01

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

  6. Streamer model for high voltage water switches

    International Nuclear Information System (INIS)

    Sazama, F.J.; Kenyon, V.L. III

    1979-01-01

    An electrical switch model for high voltage water switches has been developed which predicts streamer-switching effects that correlate well with water-switch data from Casino over the past four years and with switch data from recent Aurora/AMP experiments. Preclosure rounding and postclosure resistive damping of pulseforming line voltage waveforms are explained in terms of spatially-extensive, capacitive-coupling of the conducting streamers as they propagate across the gap and in terms of time-dependent streamer resistance and inductance. The arc resistance of the Casino water switch and of a gas switch under test on Casino was determined by computer fit to be 0.5 +- 0.1 ohms and 0.3 +- 0.06 ohms respectively, during the time of peak current in the power pulse. Energy lost in the water switch during the first pulse is 18% of that stored in the pulseforming line while similar energy lost in the gas switch is 11%. The model is described, computer transient analyses are compared with observed water and gas switch data and the results - switch resistance, inductance and energy loss during the primary power pulse - are presented

  7. High voltage isolation transformer

    Science.gov (United States)

    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.

  8. Pulse-voltage fast generator

    International Nuclear Information System (INIS)

    Valeev, R.I.; Nikiforov, M.G.; Kharchenko, A.F.

    1988-01-01

    The design is described and the test results of a four-channel pulse-voltage generator with maximum output voltage 200 kV are presented. The measurement results of generator triggering time depending on the value and polarity of the triggering voltage pulse for different triggering circuits are presented. The tests have shown stable triggering of all four channels of the generator in the range up to 40 % from selfbreakdown voltage. The generator triggering delay in the given range is <25 ns, asynchronism in channel triggering is <±1 ns

  9. Voltage Dependence of Supercapacitor Capacitance

    Directory of Open Access Journals (Sweden)

    Szewczyk Arkadiusz

    2016-09-01

    Full Text Available Electronic Double-Layer Capacitors (EDLC, called Supercapacitors (SC, are electronic devices that are capable to store a relatively high amount of energy in a small volume comparing to other types of capacitors. They are composed of an activated carbon layer and electrolyte solution. The charge is stored on electrodes, forming the Helmholtz layer, and in electrolyte. The capacitance of supercapacitor is voltage- dependent. We propose an experimental method, based on monitoring of charging and discharging a supercapacitor, which enables to evaluate the charge in an SC structure as well as the Capacitance-Voltage (C-V dependence. The measurement setup, method and experimental results of charging/discharging commercially available supercapacitors in various voltage and current conditions are presented. The total charge stored in an SC structure is proportional to the square of voltage at SC electrodes while the charge on electrodes increases linearly with the voltage on SC electrodes. The Helmholtz capacitance increases linearly with the voltage bias while a sublinear increase of total capacitance was found. The voltage on SC increases after the discharge of electrodes due to diffusion of charges from the electrolyte to the electrodes. We have found that the recovery voltage value is linearly proportional to the initial bias voltage value.

  10. Temporary over voltages in the high voltage networks

    International Nuclear Information System (INIS)

    Vukelja, Petar; Naumov, Radomir; Mrvic, Jovan; Minovski, Risto

    2001-01-01

    The paper treats the temporary over voltages that may arise in the high voltage networks as a result of: ground faults, loss of load, loss of one or two phases and switching operation. Based on the analysis, the measures for their limitation are proposed. (Original)

  11. Use of standard spectra for the short life radionuclides and ratios for long life radionuclides in the wastes of EDF PWR type reactors

    International Nuclear Information System (INIS)

    Lantes, B.; Bienvenu, Ph.

    2001-01-01

    This paper presents the type of declaration of radioactivity in the wastes of PWR type reactors park. Particularly, it insists on the justification of use of spectra for the declaration of short live radionuclides. It tackles the important developments of methods and measures of radiochemical analysis made by the Cea in order to determine the ratios to declare the long life radioisotopes. (N.C.)

  12. Method of making a long life high current density cathode from tungsten and iridium powders using a quaternary compound as the impregnant

    International Nuclear Information System (INIS)

    Branovich, L.E.; Smith, B.; Freemen, G.L.; Eckart, D.W.

    1990-01-01

    This patent describes a method of making a long life high current density cathode. It is suitable for operation in microwave devices. It is made from tungsten and iridium powders using a quaternary compound including barium, oxygen, a metal selected from the group consisting of osmium, iridium, rhodium, and rhenium, and a metal selected from the group consisting of strontium, calcium, scandium, and titanium as the impregnant

  13. Gas processing device

    International Nuclear Information System (INIS)

    Kobayashi, Yoshihiro; Seki, Eiji.

    1991-01-01

    State of electric discharge is detected based on a gas pressure in a sealed container and a discharging current flowing between both of electrodes. When electric arc discharges occur, introduction of gases to be processed is stopped and a voltage applied to both of the electrodes is interrupted. Then, when the gas pressure in the sealed container is lowered to a predetermined value, a power source voltage is applied again to both of the electrodes to recover glow discharges, and the introduction of the gas to be processed is started. With such steps, even if electric arc discharges occur, they are eliminated automatically and, accordingly, normal glow discharges can be recovered, to prevent failures of the device due to electric arc discharges. The glow discharges are recovered automatically without stopping the operation of the gas processing device, and gas injection and solidification processing can be conducted continuously and stably. (T.M.)

  14. Time varying voltage combustion control and diagnostics sensor

    Science.gov (United States)

    Chorpening, Benjamin T [Morgantown, WV; Thornton, Jimmy D [Morgantown, WV; Huckaby, E David [Morgantown, WV; Fincham, William [Fairmont, WV

    2011-04-19

    A time-varying voltage is applied to an electrode, or a pair of electrodes, of a sensor installed in a fuel nozzle disposed adjacent the combustion zone of a continuous combustion system, such as of the gas turbine engine type. The time-varying voltage induces a time-varying current in the flame which is measured and used to determine flame capacitance using AC electrical circuit analysis. Flame capacitance is used to accurately determine the position of the flame from the sensor and the fuel/air ratio. The fuel and/or air flow rate (s) is/are then adjusted to provide reduced flame instability problems such as flashback, combustion dynamics and lean blowout, as well as reduced emissions. The time-varying voltage may be an alternating voltage and the time-varying current may be an alternating current.

  15. A compact, all solid-state LC high voltage generator.

    Science.gov (United States)

    Fan, Xuliang; Liu, Jinliang

    2013-06-01

    LC generator is widely applied in the field of high voltage generation technology. A compact and all solid-state LC high voltage generator based on saturable pulse transformer is proposed in this paper. First, working principle of the generator is presented. Theoretical analysis and circuit simulation are used to verify the design of the generator. Experimental studies of the proposed LC generator with two-stage main energy storage capacitors are carried out. And the results show that the proposed LC generator operates as expected. When the isolation inductance is 27 μH, the output voltage is 1.9 times larger than the charging voltage on single capacitor. The multiplication of voltages is achieved. On the condition that the primary energy storage capacitor is charged to 857 V, the output voltage of the generator can reach to 59.5 kV. The step-up ratio is nearly 69. When self breakdown gas gap switch is used as main switch, the rise time of the voltage pulse on load resistor is 8.7 ns. It means that the series-wound inductance in the discharging circuit is very small in this system. This generator can be employed in two different applications.

  16. Demonstration of a High Open-Circuit Voltage GaN Betavoltaic Microbattery

    International Nuclear Information System (INIS)

    Cheng Zai-Jun; San Hai-Sheng; Chen Xu-Yuan; Liu Bo; Feng Zhi-Hong

    2011-01-01

    A high open-circuit voltage betavoltaic microbattery based on a GaN p-i-n diode is demonstrated. Under the irradiation of a 4×4 mm 2 planar solid 63 Ni source with an activity of 2 mCi, the open-circuit voltage V oc of the fabricated single 2×2mm 2 cell reaches as high as 1.62 V, the short-circuit current density J sc is measured to be 16nA/cm 2 . The microbattery has a fill factor of 55%, and the energy conversion efficiency of beta radiation into electricity reaches to 1.13%. The results suggest that GaN is a highly promising potential candidate for long-life betavoltaic microbatteries used as power supplies for microelectromechanical system devices. (cross-disciplinary physics and related areas of science and technology)

  17. Computer controlled high voltage system

    Energy Technology Data Exchange (ETDEWEB)

    Kunov, B; Georgiev, G; Dimitrov, L [and others

    1996-12-31

    A multichannel computer controlled high-voltage power supply system is developed. The basic technical parameters of the system are: output voltage -100-3000 V, output current - 0-3 mA, maximum number of channels in one crate - 78. 3 refs.

  18. A Voltage Quality Detection Method

    DEFF Research Database (Denmark)

    Chen, Zhe; Wei, Mu

    2008-01-01

    This paper presents a voltage quality detection method based on a phase-locked loop (PLL) technique. The technique can detect the voltage magnitude and phase angle of each individual phase under both normal and fault power system conditions. The proposed method has the potential to evaluate various...

  19. Voltage Controlled Dynamic Demand Response

    DEFF Research Database (Denmark)

    Bhattarai, Bishnu Prasad; Bak-Jensen, Birgitte; Mahat, Pukar

    2013-01-01

    Future power system is expected to be characterized by increased penetration of intermittent sources. Random and rapid fluctuations in demands together with intermittency in generation impose new challenges for power balancing in the existing system. Conventional techniques of balancing by large...... central or dispersed generations might not be sufficient for future scenario. One of the effective methods to cope with this scenario is to enable demand response. This paper proposes a dynamic voltage regulation based demand response technique to be applied in low voltage (LV) distribution feeders....... An adaptive dynamic model has been developed to determine composite voltage dependency of an aggregated load on feeder level. Following the demand dispatch or control signal, optimum voltage setting at the LV substation is determined based on the voltage dependency of the load. Furthermore, a new technique...

  20. Transient voltage oscillations in coils

    International Nuclear Information System (INIS)

    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

  1. Rad-Hard, Miniaturized, Scalable, High-Voltage Switching Module for Power Applications Rad-Hard, Miniaturized

    Science.gov (United States)

    Adell, Philippe C.; Mojarradi, Mohammad; DelCastillo, Linda Y.; Vo, Tuan A.

    2011-01-01

    A paper discusses the successful development of a miniaturized radiation hardened high-voltage switching module operating at 2.5 kV suitable for space application. The high-voltage architecture was designed, fabricated, and tested using a commercial process that uses a unique combination of 0.25 micrometer CMOS (complementary metal oxide semiconductor) transistors and high-voltage lateral DMOS (diffusion metal oxide semiconductor) device with high breakdown voltage (greater than 650 V). The high-voltage requirements are achieved by stacking a number of DMOS devices within one module, while two modules can be placed in series to achieve higher voltages. Besides the high-voltage requirements, a second generation prototype is currently being developed to provide improved switching capabilities (rise time and fall time for full range of target voltages and currents), the ability to scale the output voltage to a desired value with good accuracy (few percent) up to 10 kV, to cover a wide range of high-voltage applications. In addition, to ensure miniaturization, long life, and high reliability, the assemblies will require intensive high-voltage electrostatic modeling (optimized E-field distribution throughout the module) to complete the proposed packaging approach and test the applicability of using advanced materials in a space-like environment (temperature and pressure) to help prevent potential arcing and corona due to high field regions. Finally, a single-event effect evaluation would have to be performed and single-event mitigation methods implemented at the design and system level or developed to ensure complete radiation hardness of the module.

  2. High voltage tests of an electrostatic accelerator for different mixtures of gases at various pressures

    International Nuclear Information System (INIS)

    Hellborg, R.

    1996-01-01

    An account is given of high voltage tests of an electrostatic accelerator. High voltage conditioning is measured and is reported for the same accelerator tube after different periods of usage. Tests of different mixtures of sulphur hexafluoride and nitrogen have been performed. A considerable amount of data was obtained for various parameters connected with the high voltage system for different proportions of nitrogen in sulphur hexafluoride at various gas pressures. (orig.)

  3. Gas supply device

    International Nuclear Information System (INIS)

    Yamamoto, Tokihiro.

    1986-01-01

    Purpose: When injecting gas during plasma discharge, to prevent erronous operation of the piezoelectric valves due to vibrations and to inject gas into the vacuum vessel by accurately controlling gas flow. Constitution: The piezoelectric valve designed to control the flow of gas when charging vacuum vessels is installed between the vacuum vessel and the gas cylinder and a pulse voltage generator to control the valve (open/close) and the reverse voltage generator to apply a reverse current to the valve element are also provided. When a voltage is applied to the piezoelectric element, the piezoelectric element bends. However, when the polarity is changed, the direction of the bend is also reversed. The seat portion is pressed in proportion to the degree of bending. When gas is injected while plasma is being discharged, the gap created, due to vibrations, between the piezoelectric element and the sealing material is prevented by the application of a reverse current. This allows precise control of the gas injection volume as well as the injection interval. This assures maintenance of precise test conditions when testing thermonuclear devices. (Horiuchi, T.)

  4. Mesoporous TiO2 nanosheets anchored on graphene for ultra long life Na-ion batteries

    Science.gov (United States)

    Zhang, Ruifang; Wang, Yuankun; Zhou, Han; Lang, Jinxin; Xu, Jingjing; Xiang, Yang; Ding, Shujiang

    2018-06-01

    Sodium-ion batteries, which have a similar electrochemical reaction mechanism to lithium-ion batteries, have been considered as one of the most potential lithium-ion battery alternatives due to the rich reserves of sodium. However, it is very hard to find appropriate electrode materials imputing the large radius of sodium-ion. TiO2 is particularly interesting as anodes for sodium-ion batteries due to their reasonable operation voltage, cost, and nontoxicity. To obtain a better electrochemical property, mesoporous TiO2 nanosheets (NSs)/reduced graphene oxide (rGO) composites have been synthesized via a scalable hydrothermal-solvothermal method with a subsequent calcination process. Benefitting from unique structure design, TiO2 NSs@rGO exhibits a superior cycle stability (90 mAh g‑1 after 10 000 cycles at a high current rate of 20 C) and satisfactory rate performance (97.3 mAh g‑1 at 25 C). To our knowledge, such ultra long cycle life has not previously been reported.

  5. Inexpensive system protects megawatt resistance-heating furnace against high-voltage surges

    Science.gov (United States)

    Stearns, E. J.

    1971-01-01

    Coolant gas extinguishes arcing across the break in a heater element. Air-gap shunt which bypasses high voltage impressed across the circuit prevents damage if the resistance elements break and open the inductive circuit.

  6. LOFT voltage insertion calibaration program

    International Nuclear Information System (INIS)

    Tillitt, D.N.; Miyasaki, F.S.

    1975-08-01

    The Loss-of-Fluid Test (LOFT) Facility is an experimental facility built around a ''scaled'' version of a large pressurized water reactor (LPWR). Part of this facility is the Data Acquisition and Visual Display System (DAVDS) as defined by the LOFT System Design Document SDD 1.4.2C. The DAVDS has a 702 data channel recording capability of which 548 are recorded digitally. The DAVDS also contains a Voltage Insertion Calibration Subsystem used to inject precise and known voltage steps into the recording systems. The computer program that controls the Voltage Insertion Calibration Subsystem is presented. 7 references. (auth)

  7. Power-MOSFET Voltage Regulator

    Science.gov (United States)

    Miller, W. N.; Gray, O. E.

    1982-01-01

    Ninety-six parallel MOSFET devices with two-stage feedback circuit form a high-current dc voltage regulator that also acts as fully-on solid-state switch when fuel-cell out-put falls below regulated voltage. Ripple voltage is less than 20 mV, transient recovery time is less than 50 ms. Parallel MOSFET's act as high-current dc regulator and switch. Regulator can be used wherever large direct currents must be controlled. Can be applied to inverters, industrial furnaces photovoltaic solar generators, dc motors, and electric autos.

  8. PC-based control of a high-voltage injector

    International Nuclear Information System (INIS)

    Constantin, F.

    1998-01-01

    The stability of high voltage injectors is one of the major problems in any accelerator system. Most of the troubles encountered in the normal operation of an accelerator are connected with the ion source and associated high voltage platforms, regardless of the source or high voltage generator type. The quality of the ion beam injected in the accelerator strongly depends on the power supplies used in the injector and on the ability to control the non-electrical parameters (gas-flow, temperature, etc.). A wide used method in controlling is based on optical links between high-voltage platform and computer, the adjustments being more or less automated. Although the method mentioned above can be still useful in injector control, a different approach is presented in this work, i.e., the computer itself is placed inside the high-voltage terminal. Only one optical link is still necessary to connect this computer with an user-friendly host at ground potential. Requirements: - varying and monitoring the filament current; - gas flow control in the ion source; - reading the vacuum values; - current and voltage control for the anodic, magnet, extraction, suppression and lens' sources. Even in the high voltage terminal there are compartments with different voltages regardless the floating ground. In our injector the extraction voltage is applied on the top of the ion source including the filament and the anodic voltage. The extraction voltage is of maximum 30 kV. In this situation a second optical link is required to transfer the control for the anodic and magnet source power supply assuming the dedicated computer on the floating ground. One PC is placed inside the high voltage terminal and one PC outside the injector. The optical link (more precisely two optical wires) connects the serial ports. The inside computer is equipped with two multipurpose ADC/DAC and digital I/O card. They permit to read or output DC levels ranging between 0 to 10 volts or TTL signals. The filament

  9. A high-voltage test for the ATLAS RPC qualification

    CERN Document Server

    Aielli, G; Cardarelli, R; Di Ciaccio, A; Di Simone, A; Liberti, B; Santonico, R

    2004-01-01

    The RPC production sequence for the ATLAS experiment includes a specific test of current absorption at the operating point, which concerns the RPC "gas volumes", namely the bare detectors not yet assembled with the read-out panels and the mechanical support structures. The test, which is carried out at the production site, consists of two phases. The gas volumes are initially conditioned with pure argon, keeping the voltage constant just above the breakdown value of about 2 kV. The final test, performed after the volumes have undergone inner surface varnishing with linseed oil, is based on the measurement of the current-voltage characteristics with the binary operating gas, C//2H//2F//4/i-C//4H//1//0 = 95/5. The results presented here concern 45% of the total foreseen production.

  10. A high-voltage test for the ATLAS RPC qualification

    International Nuclear Information System (INIS)

    Aielli, G.; Camarri, P.; Cardarelli, R.; Di Ciaccio, A.; Di Simone, A.; Liberti, B.; Santonico, R.

    2004-01-01

    The RPC production sequence for the ATLAS experiment includes a specific test of current absorption at the operating point, which concerns the RPC 'gas volumes', namely the bare detectors not yet assembled with the read-out panels and the mechanical support structures. The test, which is carried out at the production site, consists of two phases. The gas volumes are initially conditioned with pure argon, keeping the voltage constant just above the breakdown value of about 2 kV. The final test, performed after the volumes have undergone inner surface varnishing with linseed oil, is based on the measurement of the current-voltage characteristics with the binary operating gas, C2H2F4/i-C4H10=95/5. The results presented here concern 45% of the total foreseen production

  11. Rancang Bangun Sistem Pengaman Kebocoran Gas LPG (Liquefied Petroleum Gas) Menggunakan Mikrokontroler

    OpenAIRE

    Ismai, Reza Lutfi; Suseno, Jatmiko Endro; Suryono, Suryono

    2017-01-01

    Design of LPG gas leakage safety system using microcontroller has been made in this research. The purpose of this research is to make LPG gas sensor circuit to detect LPG gas concentration and make automation systems for LPG gas leakage protection. LPG gas leakage protection system can be applied for the use of LPG gas safely. Component to detect LPG gas concentration use sensor MQ 5 which can gives resistance as the output value which can be converted into voltage through the voltage devider...

  12. Modular High Voltage Power Supply

    Energy Technology Data Exchange (ETDEWEB)

    Newell, Matthew R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-05-18

    The goal of this project is to develop a modular high voltage power supply that will meet the needs of safeguards applications and provide a modular plug and play supply for use with standard electronic racks.

  13. High-voltage pulsed generator for dynamic fragmentation of rocks.

    Science.gov (United States)

    Kovalchuk, B M; Kharlov, A V; Vizir, V A; Kumpyak, V V; Zorin, V B; Kiselev, V N

    2010-10-01

    A portable high-voltage (HV) pulsed generator has been designed for rock fragmentation experiments. The generator can be used also for other technological applications. The installation consists of low voltage block, HV block, coaxial transmission line, fragmentation chamber, and control system block. Low voltage block of the generator, consisting of a primary capacitor bank (300 μF) and a thyristor switch, stores pulse energy and transfers it to the HV block. The primary capacitor bank stores energy of 600 J at the maximum charging voltage of 2 kV. HV block includes HV pulsed step up transformer, HV capacitive storage, and two electrode gas switch. The following technical parameters of the generator were achieved: output voltage up to 300 kV, voltage rise time of ∼50 ns, current amplitude of ∼6 kA with the 40 Ω active load, and ∼20 kA in a rock fragmentation regime (with discharge in a rock-water mixture). Typical operation regime is a burst of 1000 pulses with a frequency of 10 Hz. The operation process can be controlled within a wide range of parameters. The entire installation (generator, transmission line, treatment chamber, and measuring probes) is designed like a continuous Faraday's cage (complete shielding) to exclude external electromagnetic perturbations.

  14. High-voltage pulsed generator for dynamic fragmentation of rocks

    Science.gov (United States)

    Kovalchuk, B. M.; Kharlov, A. V.; Vizir, V. A.; Kumpyak, V. V.; Zorin, V. B.; Kiselev, V. N.

    2010-10-01

    A portable high-voltage (HV) pulsed generator has been designed for rock fragmentation experiments. The generator can be used also for other technological applications. The installation consists of low voltage block, HV block, coaxial transmission line, fragmentation chamber, and control system block. Low voltage block of the generator, consisting of a primary capacitor bank (300 μF) and a thyristor switch, stores pulse energy and transfers it to the HV block. The primary capacitor bank stores energy of 600 J at the maximum charging voltage of 2 kV. HV block includes HV pulsed step up transformer, HV capacitive storage, and two electrode gas switch. The following technical parameters of the generator were achieved: output voltage up to 300 kV, voltage rise time of ˜50 ns, current amplitude of ˜6 kA with the 40 Ω active load, and ˜20 kA in a rock fragmentation regime (with discharge in a rock-water mixture). Typical operation regime is a burst of 1000 pulses with a frequency of 10 Hz. The operation process can be controlled within a wide range of parameters. The entire installation (generator, transmission line, treatment chamber, and measuring probes) is designed like a continuous Faraday's cage (complete shielding) to exclude external electromagnetic perturbations.

  15. Reliability criteria for voltage stability

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Carson W; Silverstein, Brian L [Bonneville Power Administration, Portland, OR (United States)

    1994-12-31

    In face of costs pressures, there is need to allocate scare resources more effectively in order to achieve voltage stability. This naturally leads to development of probabilistic criteria and notions of rick management. In this paper it is presented a discussion about criteria for long term voltage stability limited to the case in which the time frames are topically several minutes. (author) 14 refs., 1 fig.

  16. High voltage distributions in RPCs

    International Nuclear Information System (INIS)

    Inoue, Y.; Muranishi, Y.; Nakamura, M.; Nakano, E.; Takahashi, T.; Teramoto, Y.

    1996-01-01

    High voltage distributions on the inner surfaces of RPCs electrodes were calculated by using a two-dimensional resistor network model. The calculated result shows that the surface resistivity of the electrodes should be high, compared to their volume resistivity, to get a uniform high voltage over the surface. Our model predicts that the rate capabilities of RPCs should be inversely proportional to the thickness of the electrodes if the ratio of surface-to-volume resistivity is low. (orig.)

  17. Macroeconomic Assessment of Voltage Sags

    Directory of Open Access Journals (Sweden)

    Sinan Küfeoğlu

    2016-12-01

    Full Text Available The electric power sector has changed dramatically since the 1980s. Electricity customers are now demanding uninterrupted and high quality service from both utilities and authorities. By becoming more and more dependent on the voltage sensitive electronic equipment, the industry sector is the one which is affected the most by voltage disturbances. Voltage sags are one of the most crucial problems for these customers. The utilities, on the other hand, conduct cost-benefit analyses before going through new investment projects. At this point, understanding the costs of voltage sags become imperative for planning purposes. The characteristics of electric power consumption and hence the susceptibility against voltage sags differ considerably among different industry subsectors. Therefore, a model that will address the estimation of worth of electric power reliability for a large number of customer groups is necessary. This paper introduces a macroeconomic model to calculate Customer Voltage Sag Costs (CVSCs for the industry sector customers. The proposed model makes use of analytical data such as value added, annual energy consumption, working hours, and average outage durations and provides a straightforward, credible, and easy to follow methodology for the estimation of CVSCs.

  18. A matter of quantum voltages

    Energy Technology Data Exchange (ETDEWEB)

    Sellner, Bernhard; Kathmann, Shawn M., E-mail: Shawn.Kathmann@pnnl.gov [Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States)

    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.

  19. Advances in high voltage insulation and arc interruption in SF6 and vacuum

    CERN Document Server

    Maller, V N

    1982-01-01

    Advances in High Voltage Insulation and Arc Interruption in SF6 and Vacuum deals with high voltage breakdown and arc extinction in sulfur hexafluoride (SF6) and high vacuum, with special emphasis on the application of these insulating media in high voltage power apparatus and devices. The design and developmental aspects of various high voltage power apparatus using SF6 and high vacuum are highlighted. This book is comprised of eight chapters and opens with a discussion on electrical discharges in SF6 and high vacuum, along with the properties and handling of SF6 gas. The following chapters fo

  20. High voltage nanosecond generator with pulse repetition rate of 1,000 p.p.s.

    Energy Technology Data Exchange (ETDEWEB)

    Gubanov, V P; Korovin, S D; Stepchenko, A S [High Current Electronics Institute, Tomsk (Russian Federation)

    1997-12-31

    A compact high voltage nanosecond generator is described with a pulse repetition rate up to 1000 p.p.s. The generator includes a 30-Ohm coaxial forming line charged by a built-in Tesla transformer with a high coupling coefficient, and a high voltage (N{sub 2}) gas gap switch with gas blowing between the electrodes. The maximum forming line charge voltage is 450 kV, the pulse duration is about 4 ns, and its amplitude for a matched load is up to 200 kV. (author). 3 figs., 9 refs.

  1. A New Contribution in Reducing Electric Field Distribution Within/Around Medium Voltage Underground Cable Terminations

    Directory of Open Access Journals (Sweden)

    S. S. Desouky

    2017-10-01

    Full Text Available Ιn medium voltage cables, the stress control layers play an important part in controlling the electric field distribution around the medium voltage underground cable terminations. Underground cable accessories, used in medium voltage cable systems, need a stress control tube in order to maintain and control the insulation level which is designed for long life times. The term “electrical stress control” refers to the cable termination analysis of optimizing the electrical stress in the area of insulation shield cutback to reduce the electrical field concentration at this point in order to reduce breakdown in the cable insulation. This paper presents the effect of some materials of different relative permittivities and geometrical regulation with the curved shape stress relief cones on the electric field distribution of cable termination. The optimization was done by comparing the results of eight materials used. Also, the effect of the change in the thickness of the stress control tube is presented. The modeling design is very important for engineers to find the optimal solution of terminator design of medium voltage cables. This paper also describes the evolution of stress control systems and their benefits. A developed program using Finite Element Method (FEM has calculated a numerical study to the stress control layering electric field distribution.

  2. Safety performance comparation of MOX, nitride and metallic fuel based 25-100 MWe Pb-Bi cooled long life fast reactors without on-site refuelling

    International Nuclear Information System (INIS)

    Su'ud, Zaki

    2008-01-01

    In this paper the safety performance of 25-100 MWe Pb-Bi cooled long life fast reactors based on three types of fuels: MOX, nitride and metal is compared and discussed. In the fourth generation NPP paradigm, especially for Pb-Bi cooled fast reactors, inherent safety capability is necessary against some standard accidents such as unprotected loss of flow (ULOF), unprotected rod run-out transient over power (UTOP), unprotected loss of heat sink (ULOHS). Selection of fuel type will have important impact on the overall system safety performance. The results of safety analysis of long life Pb-Bi cooled fast reactors without on-site fuelling using nitride, MOX and metal fuel have been performed. The reactors show the inherent safety pattern with enough safety margins during ULOF and UTOP accidents. For MOX fuelled reactors, ULOF accident is more severe than UTOP accident while for nitride fuelled cores UTOP accident may push power much higher than that comparable MOX fuelled cores. (author)

  3. Mitigation of voltage sags in the distribution system with dynamic voltage restorer

    International Nuclear Information System (INIS)

    Viglas, D.; Belan, A.

    2012-01-01

    Dynamic voltage restorer is a custom power device that is used to improve voltage sags or swells in electrical distribution system. The components of the Dynamic Voltage Restorer consist of injection transformers, voltage source inverter, passive filters and energy storage. The main function of the Dynamic voltage restorer is used to inject three phase voltage in series and in synchronism with the grid voltages in order to compensate voltage disturbances. This article deals with mitigation of voltage sags caused by three-phase short circuit. Dynamic voltage restorer is modelled in MATLAB/Simulink. (Authors)

  4. Report on the results of the FY 1999 R and D of polymer electrolyte fuel cells. Development of the power system technology (Development of high voltage several 10 kW class dispersed generation system); 1999 nendo kotai kobunshigata nenryo denchi no kenkyu kaihatsu seika hokokusho. Hatsuden system gijutsu no kaihatsu (koden'atsugata suju kW kyu bunsan dengen system no kaihatsu)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    The paper described the results of the FY 1999 development of polymer electrolyte fuel cell and several 10 kW class dispersed generation system. The humidification of the cell body is the internal humidification method in which water is directly supplied to cell, which makes the cell life long. The cooling using latent heat of vaporization of the water supplied makes the temperature distribution inside the cell face homogeneous. In the test for long life, the system was stably operated at voltage lowering speed of 11mV/1000h. The optimization of water supply structure in the stack increases the latent heat cooling amount and makes the temperature distribution inside the cell face homogeneous. The reduction of CO concentration in reformed gas is extremely important for improvement of cell performance and long-term stabilization of cell voltage. By the two-stage structure selective oxidation device, the CO concentration at inlet, 5,000 ppm, can be reduced to below 10 ppm at outlet. In the demonstrative experiment on the several 10 kW class dispersed generation system, efforts for reduction in size of structural equipment and package were made, and a possible size of 200*150*180cm was obtained. Based on the chart of 30kW class system flow, the heat material balance was analyzed, and the power generation efficiency of 40% at a.c. sending end and overall efficiency of 80% were confirmed. (NEDO)

  5. Effects of load voltage on voltage breakdown modes of electrical exploding aluminum wires in air

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jian; Li, Xingwen, E-mail: xwli@mail.xjtu.edu.cn; Yang, Zefeng; Wang, Kun; Chao, Youchuang; Shi, Zongqian; Jia, Shenli; Qiu, Aici [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China)

    2015-06-15

    The effects of the load voltage on the breakdown modes are investigated in exploding aluminum wires driven by a 1 kA, 0.1 kA/ns pulsed current in air. From laser probing images taken by laser shadowgraphy, schlieren imaging, and interferometry, the position of the shockwave front, the plasma channel, and the wire core edge of the exploding product can be determined. The breakdown mode makes a transition from the internal mode, which involves breakdown inside the wire core, to the shunting mode, which involves breakdown in the compressed air, with decreasing charging voltage. The breakdown electrical field for a gaseous aluminum wire core of nearly solid density is estimated to be more than 20 kV/cm, while the value for gaseous aluminum of approximately 0.2% solid density decreases to 15–20 kV/cm. The breakdown field in shunting mode is less than 20 kV/cm and is strongly affected by the vaporized aluminum, the desorbed gas, and the electrons emitted from the wire core during the current pause. Ohmic heating during voltage collapses will induce further energy deposition in the current channel and thus will result in different expansion speeds for both the wire core and the shockwave front in the different modes.

  6. Gas and Gas Pains

    Science.gov (United States)

    ... to produce gas. Often, relatively simple changes in eating habits can lessen bothersome gas. Certain digestive system disorders, ... such as soda and beer, increase stomach gas. Eating habits, such as eating too quickly, drinking through a ...

  7. Low-Energy Real-Time OS Using Voltage Scheduling Algorithm for Variable Voltage Processors

    OpenAIRE

    Okuma, Takanori; Yasuura, Hiroto

    2001-01-01

    This paper presents a real-time OS based on $ mu $ITRON using proposed voltage scheduling algorithm for variable voltage processors which can vary supply voltage dynamically. The proposed voltage scheduling algorithms assign voltage level for each task dynamically in order to minimize energy consumption under timing constraints. Using the presented real-time OS, running tasks with low supply voltage leads to drastic energy reduction. In addition, the presented voltage scheduling algorithm is ...

  8. Development of a New Cascade Voltage-Doubler for Voltage Multiplication

    OpenAIRE

    Toudeshki, Arash; Mariun, Norman; Hizam, Hashim; Abdul Wahab, Noor Izzri

    2014-01-01

    For more than eight decades, cascade voltage-doubler circuits are used as a method to produce DC output voltage higher than the input voltage. In this paper, the topological developments of cascade voltage-doublers are reviewed. A new circuit configuration for cascade voltage-doubler is presented. This circuit can produce a higher value of the DC output voltage and better output quality compared to the conventional cascade voltage-doubler circuits, with the same number of stages.

  9. Cavity Voltage Phase Modulation MD

    CERN Document Server

    Mastoridis, Themistoklis; Molendijk, John; Timko, Helga; CERN. Geneva. ATS Department

    2016-01-01

    The LHC RF/LLRF system is currently configured for extremely stable RF voltage to minimize transient beam loading effects. The present scheme cannot be extended beyond nominal beam current since the demanded power would exceed the peak klystron power and lead to saturation. A new scheme has therefore been proposed: for beam currents above nominal (and possibly earlier), the cavity phase modulation by the beam will not be corrected (transient beam loading), but the strong RF feedback and One-Turn Delay feedback will still be active for loop and beam stability in physics. To achieve this, the voltage set point will be adapted for each bunch. The goal of this MD was to test a new algorithm that would adjust the voltage set point to achieve the cavity phase modulation that would minimize klystron forward power.

  10. Design of shielded voltage divider for impulse voltage measurement

    International Nuclear Information System (INIS)

    Kato, Shohei; Kouno, Teruya; Maruyama, Yoshio; Kikuchi, Koji.

    1976-01-01

    The dividers used for the study of the insulation and electric discharge phenomena in high voltage equipments have the problems of the change of response characteristics owing to adjacent bodies and of induced noise. To improve the characteristics, the enclosed type divider shielded with metal has been investigated, and the divider of excellent response has been obtained by adopting the frequency-separating divider system, which is divided into two parts, resistance divider (lower frequency region) and capacitance divider (higher frequency region), for avoiding to degrade the response. Theoretical analysis was carried out in the cases that residual inductance can be neglected or can not be neglected in the small capacitance divider, and that the connecting wires are added. Next, the structure of the divider and the design of the electric field for the divider manufactured on the basis of the theory are described. The response characteristics were measured. The results show that 1 MV impulse voltage can be measured within the response time of 10 ns. Though this divider aims at the impulse voltage, the duration time of which is about that of standard lightning impulse, in view of the heat capacity because of the input resistance of 10.5 kΩ, it is expected that the divider can be applied to the voltage of longer duration time by increasing the input resistance in future. (Wakatsuki, Y.)

  11. Unbalanced Voltage Compensation in Low Voltage Residential AC Grids

    DEFF Research Database (Denmark)

    Trintis, Ionut; Douglass, Philip; Munk-Nielsen, Stig

    2016-01-01

    This paper describes the design and test of a control algorithm for active front-end rectifiers that draw power from a residential AC grid to feed heat pump loads. The control algorithm is able to control the phase to neutral or phase to phase RMS voltages at the point of common coupling...

  12. The high voltage homopolar generator

    Science.gov (United States)

    Price, J. H.; Gully, J. H.; Driga, M. D.

    1986-11-01

    System and component design features of proposed high voltage homopolar generator (HVHPG) are described. The system is to have an open circuit voltage of 500 V, a peak output current of 500 kA, 3.25 MJ of stored inertial energy and possess an average magnetic-flux density of 5 T. Stator assembly components are discussed, including the stator, mount structure, hydrostatic bearings, main and motoring brushgears and rotor. Planned operational procedures such as monitoring the rotor to full speed and operation with a superconducting field coil are delineated.

  13. Resilient architecture design for voltage variation

    CERN Document Server

    Reddi, Vijay Janapa

    2013-01-01

    Shrinking feature size and diminishing supply voltage are making circuits sensitive to supply voltage fluctuations within the microprocessor, caused by normal workload activity changes. If left unattended, voltage fluctuations can lead to timing violations or even transistor lifetime issues that degrade processor robustness. Mechanisms that learn to tolerate, avoid, and eliminate voltage fluctuations based on program and microarchitectural events can help steer the processor clear of danger, thus enabling tighter voltage margins that improve performance or lower power consumption. We describe

  14. Alarm radiation dosimeter with improved integrating pulse ionization chamber and high voltage supply

    International Nuclear Information System (INIS)

    Borkowski, C.J.; Rochelle, J.M.

    1975-01-01

    An alarm dosimeter is described which features an improved integrating pulse ionization chamber of the type containing an hermetically sealed gas diode. Improved operation and miniaturization of the chamber are made possible by a ringing choke converter high voltage supply having a ripple-type output that insures discharge of the gas diode. (author)

  15. Cathode voltage and discharge current oscillations in HiPIMS

    Czech Academy of Sciences Publication Activity Database

    Klein, P.; Hnilica, J.; Hubička, Zdeněk; Čada, Martin; Šlapanská, M.; Zemánek, M.; Vašina, P.

    2017-01-01

    Roč. 26, č. 5 (2017), s. 1-12, č. článku 055015. ISSN 0963-0252 R&D Projects: GA ČR(CZ) GA15-00863S Institutional support: RVO:68378271 Keywords : HiPIMS * voltage and current oscillations * spokes Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 3.302, year: 2016

  16. Ultra Fast, High Rep Rate, High Voltage Spark Gap Pulser

    Science.gov (United States)

    1995-07-01

    current rise time. The spark gap was designed to have a coaxial geometry reducing its inductance. Provisions were made to pass flowing gas between the...ULTRA FAST, HIGH REP RATE, HIGH VOLTAGE SPARK GAP PULSER Robert A. Pastore Jr., Lawrence E. Kingsley, Kevin Fonda, Erik Lenzing Electrophysics and...Modeling Branch AMSRL-PS-EA Tel.: (908)-532-0271 FAX: (908)-542-3348 U.S. Army Research Laboratory Physical Sciences Directorate Ft. Monmouth

  17. A high voltage DC switching power supply of corona discharge for ozone tube

    International Nuclear Information System (INIS)

    Ketkaew, Siseerot

    2007-08-01

    Full text: This paper presents a study of design and construction of a high voltage DC switching power supply for corona generating of ozone gas generating. This supply uses fly back converter at 3 k Vdc 30 khz and controls its operation using PWM techniques. I C TL494 is controlled of the switching. The testing of supply by putting high voltage to ozone gas tube at one-hour, the oxygen quantity 21 % of air, which ozone tube model enables ozone gas generating capacity of 95.2 mgO3/hr

  18. Voltage Weak DC Distribution Grids

    NARCIS (Netherlands)

    Hailu, T.G.; Mackay, L.J.; Ramirez Elizondo, L.M.; Ferreira, J.A.

    2017-01-01

    This paper describes the behavior of voltage weak DC distribution systems. These systems have relatively small system capacitance. The size of system capacitance, which stores energy, has a considerable effect on the value of fault currents, control complexity, and system reliability. A number of

  19. Nonlinear electrokinetics at large voltages

    Energy Technology Data Exchange (ETDEWEB)

    Bazant, Martin Z [Department of Chemical Engineering and Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Sabri Kilic, Mustafa; Ajdari, Armand [Department of Mathematics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Storey, Brian D [Franklin W Olin College of Engineering, Needham, MA 02492 (United States)], E-mail: bazant@mit.edu

    2009-07-15

    The classical theory of electrokinetic phenomena assumes a dilute solution of point-like ions in chemical equilibrium with a surface whose double-layer voltage is of order the thermal voltage, k{sub B}T/e=25 mV. In nonlinear 'induced-charge' electrokinetic phenomena, such as ac electro-osmosis, several volts {approx}100k{sub B}T/e are applied to the double layer, and the theory breaks down and cannot explain many observed features. We argue that, under such a large voltage, counterions 'condense' near the surface, even for dilute bulk solutions. Based on simple models, we predict that the double-layer capacitance decreases and the electro-osmotic mobility saturates at large voltages, due to steric repulsion and increased viscosity of the condensed layer, respectively. The former suffices to explain observed high-frequency flow reversal in ac electro-osmosis; the latter leads to a salt concentration dependence of induced-charge flows comparable to experiments, although a complete theory is still lacking.

  20. High voltage power network construction

    CERN Document Server

    Harker, Keith

    2018-01-01

    This book examines the key requirements, considerations, complexities and constraints relevant to the task of high voltage power network construction, from design, finance, contracts and project management to installation and commissioning, with the aim of providing an overview of the holistic end to end construction task in a single volume.

  1. Voltage control of ferromagnetic resonance

    Directory of Open Access Journals (Sweden)

    Ziyao Zhou

    2016-06-01

    Full Text Available 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.

  2. High voltage MOSFET switching circuit

    Science.gov (United States)

    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.

  3. Assessment of costs related to the implementation of management solutions on the long term for high and medium level long life radioactive wastes. ANDRA's proposition

    International Nuclear Information System (INIS)

    2014-10-01

    This huge document contains several volumes which propose detailed costing of the various parts of the Cigeo project after sketch studies (this project deals with the deep geological storage of high and medium level long life radioactive wastes). It notably states the various hypotheses regarding the inventory of radioactive wastes, the waste supply prediction, and works closure. This cost assessment takes the different project stages into account and a cost update. Various aspects are thus assessed, some related to investments (design studies, preliminary works, construction of the various installations, renewal of equipment during exploitation, installation dismantling and works closure, insurance, commissioning authority and engineering subcontracting), to exploitation (production and maintenance, support, activities related to safety, radiation protection and control of the environment, operating costs, utilities, storage containers, insurance), and to other expenses (tax, research and development, technological tests, control after closure)

  4. Nitrogen-doped carbon decorated Cu2NiSnS4 microflowers as superior anode materials for long-life lithium-ion batteries

    Science.gov (United States)

    Pan, Pei; Chen, Lihui; Ding, Yu; Du, Jun; Feng, Chuanqi; Fu, Zhengbin; Qin, Caiqin; Wang, Feng

    2018-05-01

    Nitrogen-doped carbon (NC) decorated Cu2NiSnS4 (CNTS) microflower composites (NC@CNTS) were fabricated through a facile solvothermal and pyrrole polymerization with further annealing treatment. The NC@CNTS composites possessed a three-dimension (3D) microflower-like hierarchical structure. The unique microflower structure of NC@CNTS composites exhibited remarkable electrochemical performance as electrode materials for long life lithium ion batteries. The as-prepared composites had a stable and reversible capacity that reached 943 mA h g-1 after 160 cycles at a current rate of 0.1 A g-1. It showed satisfactory cycle stability and rate capability even at 2 A g-1, and specific capacity stabilized at 288 mA g-1 after 1000 cycles. The present facile and cost-effective strategy can be applied for the synthesis of other transition metal sulfide nanomaterials for energy storage and conversion applications.

  5. Copper Silicate Hydrate Hollow Spheres Constructed by Nanotubes Encapsulated in Reduced Graphene Oxide as Long-Life Lithium-Ion Battery Anode.

    Science.gov (United States)

    Wei, Xiujuan; Tang, Chunjuan; Wang, Xuanpeng; Zhou, Liang; Wei, Qiulong; Yan, Mengyu; Sheng, Jinzhi; Hu, Ping; Wang, Bolun; Mai, Liqiang

    2015-12-09

    Hierarchical copper silicate hydrate hollow spheres-reduced graphene oxide (RGO) composite is successfully fabricated by a facile hydrothermal method using silica as in situ sacrificing template. The electrochemical performance of the composite as lithium-ion battery anode was studied for the first time. Benefiting from the synergistic effect of the hierarchical hollow structure and conductive RGO matrix, the composite exhibits excellent long-life performance and rate capability. A capacity of 890 mAh/g is achieved after 200 cycles at 200 mA/g and a capacity of 429 mAh/g is retained after 800 cycles at 1000 mA/g. The results indicate that the strategy of combining hierarchical hollow structures with conductive RGO holds the potential in addressing the volume expansion issue of high capacity anode materials.

  6. Voltage linear transformation circuit design

    Science.gov (United States)

    Sanchez, Lucas R. W.; Jin, Moon-Seob; Scott, R. Phillip; Luder, Ryan J.; Hart, Michael

    2017-09-01

    Many engineering projects require automated control of analog voltages over a specified range. We have developed a computer interface comprising custom hardware and MATLAB code to provide real-time control of a Thorlabs adaptive optics (AO) kit. The hardware interface includes an op amp cascade to linearly shift and scale a voltage range. With easy modifications, any linear transformation can be accommodated. In AO applications, the design is suitable to drive a range of different types of deformable and fast steering mirrors (FSM's). Our original motivation and application was to control an Optics in Motion (OIM) FSM which requires the customer to devise a unique interface to supply voltages to the mirror controller to set the mirror's angular deflection. The FSM is in an optical servo loop with a wave front sensor (WFS), which controls the dynamic behavior of the mirror's deflection. The code acquires wavefront data from the WFS and fits a plane, which is subsequently converted into its corresponding angular deflection. The FSM provides +/-3° optical angular deflection for a +/-10 V voltage swing. Voltages are applied to the mirror via a National Instruments digital-to-analog converter (DAC) followed by an op amp cascade circuit. This system has been integrated into our Thorlabs AO testbed which currently runs at 11 Hz, but with planned software upgrades, the system update rate is expected to improve to 500 Hz. To show that the FSM subsystem is ready for this speed, we conducted two different PID tuning runs at different step commands. Once 500 Hz is achieved, we plan to make the code and method for our interface solution freely available to the community.

  7. Effect of non-uniform Hall parameter on the electrode voltage drop in Faraday-type combustion MHD generators

    International Nuclear Information System (INIS)

    Gupta, G.P.; Rohatgi, V.K.

    1982-01-01

    Following a simplified approach, an expression is derived for the gas-dynamic voltage drop in a finitely segmented Faraday-type combustion MHD generator, taking into account the non-uniform Hall parameter across the channel. Combining the electrical sheath voltage drop, discussed briefly, with the gas-dynamic voltage drop, the effect of a non-uniform Hall parameter on the electrode voltage drop is studied using the theoretical and experimental input parameters of the Indian MHD channel test. The condition for the validity of the usual assumption of uniform Hall parameter across the channel is pointed out. Analysis of the measured electrode voltage drop predicts the real gas conductivity in the core to be in the range of 60 to 75 per cent of the theoretically calculated core conductivity. (author)

  8. Analyzing randomly occurring voltage breakdowns

    International Nuclear Information System (INIS)

    Wiltshire, C.W.

    1977-01-01

    During acceptance testing of high-vacuum neutron tubes, 40% of the tubes failed after experiencing high-voltage breakdowns during the aging process. Use of a digitizer in place of an oscilloscope revealed two types of breakdowns, only one of which affected acceptance testing. This information allowed redesign of the aging sequence to prevent tube damage and improve yield and quality of the final product

  9. Advances in high voltage engineering

    CERN Document Server

    Haddad, A

    2005-01-01

    This book addresses the very latest research and development issues in high voltage technology and is intended as a reference source for researchers and students in the field, specifically covering developments throughout the past decade. This unique blend of expert authors and comprehensive subject coverage means that this book is ideally suited as a reference source for engineers and academics in the field for years to come.

  10. High-voltage CMOS detectors

    International Nuclear Information System (INIS)

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

    2016-01-01

    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. - Highlights: • High-voltage CMOS sensors will be used in Mu3e experiment at PSI (Switzerland). • HVCMOS sensors are considered as an option for ATLAS (LHC/CERN) and CLIC (CERN). • Efficiency of more than 95% (99%) has been measured with (un-)irradiated chips. • The time resolution measured in the beam tests is nearly 100 ns. • We plan to improve time resolution and efficiency by using high-resistive substrate.

  11. Low voltage electron beam accelerators

    International Nuclear Information System (INIS)

    Ochi, Masafumi

    2003-01-01

    Widely used electron accelerators in industries are the electron beams with acceleration voltage at 300 kV or less. The typical examples are shown on manufactures in Japan, equipment configuration, operation, determination of process parameters, and basic maintenance requirement of the electron beam processors. New electron beam processors with acceleration voltage around 100 kV were introduced maintaining the relatively high dose speed capability of around 10,000 kGy x mpm at production by ESI (Energy Science Inc. USA, Iwasaki Electric Group). The application field like printing and coating for packaging requires treating thickness of 30 micron or less. It does not require high voltage over 110 kV. Also recently developed is a miniature bulb type electron beam tube with energy less than 60 kV. The new application area for this new electron beam tube is being searched. The drive force of this technology to spread in the industries would be further development of new application, process and market as well as the price reduction of the equipment, upon which further acknowledgement and acceptance of the technology to societies and industries would entirely depend. (Y. Tanaka)

  12. High-voltage CMOS detectors

    Energy Technology Data Exchange (ETDEWEB)

    Ehrler, F., E-mail: felix.ehrler@student.kit.edu; Blanco, R.; Leys, R.; Perić, I.

    2016-07-11

    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. - Highlights: • High-voltage CMOS sensors will be used in Mu3e experiment at PSI (Switzerland). • HVCMOS sensors are considered as an option for ATLAS (LHC/CERN) and CLIC (CERN). • Efficiency of more than 95% (99%) has been measured with (un-)irradiated chips. • The time resolution measured in the beam tests is nearly 100 ns. • We plan to improve time resolution and efficiency by using high-resistive substrate.

  13. Low voltage electron beam accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Ochi, Masafumi [Iwasaki Electric Co., Ltd., Tokyo (Japan)

    2003-02-01

    Widely used electron accelerators in industries are the electron beams with acceleration voltage at 300 kV or less. The typical examples are shown on manufactures in Japan, equipment configuration, operation, determination of process parameters, and basic maintenance requirement of the electron beam processors. New electron beam processors with acceleration voltage around 100 kV were introduced maintaining the relatively high dose speed capability of around 10,000 kGy x mpm at production by ESI (Energy Science Inc. USA, Iwasaki Electric Group). The application field like printing and coating for packaging requires treating thickness of 30 micron or less. It does not require high voltage over 110 kV. Also recently developed is a miniature bulb type electron beam tube with energy less than 60 kV. The new application area for this new electron beam tube is being searched. The drive force of this technology to spread in the industries would be further development of new application, process and market as well as the price reduction of the equipment, upon which further acknowledgement and acceptance of the technology to societies and industries would entirely depend. (Y. Tanaka)

  14. Light-voltage conversion apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Fujioka, Yoshiki

    1987-09-19

    In a light-voltage conversion unit, when input signal is applied, the output signal to the control circuit has quick rise-up time and slow breaking time. In order to improve this, a short-circuit transistor is placed at the diode, and this transistor is forced ON, when an output signal to the control circuit is lowered down to a constant voltage, to short-circuit between the output terminals. This, however, has a demerit of high power consumption by a transistor. In this invention, by connecting a light-emitting element which gets ON at the first transition and a light-emitting element which gets ON at the last transition, placing a light receiving element in front of each light-emitting element, when an input signal is applied; thus a load is driven only with ON signal of each light-emitting element, eliminating the delay in the last transition. All of these give a quick responsive light-voltage conversion without unnecessary power consumption. (5 figs)

  15. [Development of residual voltage testing equipment].

    Science.gov (United States)

    Zeng, Xiaohui; Wu, Mingjun; Cao, Li; He, Jinyi; Deng, Zhensheng

    2014-07-01

    For the existing measurement methods of residual voltage which can't turn the power off at peak voltage exactly and simultaneously display waveforms, a new residual voltage detection method is put forward in this paper. First, the zero point of the power supply is detected with zero cross detection circuit and is inputted to a single-chip microcomputer in the form of pulse signal. Secend, when the zero point delays to the peak voltage, the single-chip microcomputer sends control signal to power off the relay. At last, the waveform of the residual voltage is displayed on a principal computer or oscilloscope. The experimental results show that the device designed in this paper can turn the power off at peak voltage and is able to accurately display the voltage waveform immediately after power off and the standard deviation of the residual voltage is less than 0.2 V at exactly one second and later.

  16. Symmetric voltage-controlled variable resistance

    Science.gov (United States)

    Vanelli, J. C.

    1978-01-01

    Feedback network makes resistance of field-effect transistor (FET) same for current flowing in either direction. It combines control voltage with source and load voltages to give symmetric current/voltage characteristics. Since circuit produces same magnitude output voltage for current flowing in either direction, it introduces no offset in presense of altering polarity signals. It is therefore ideal for sensor and effector circuits in servocontrol systems.

  17. Ultra Low-Voltage Energy Harvesting

    Science.gov (United States)

    2013-09-01

    if in a solar battery charger the level of illumination were to drop due to cloud cover, the diode would prevent discharging of the battery when...the source voltage becomes lower than battery voltage. The drawback of a simple circuit like this is that once the source voltage is lower than the...longer charged when the battery voltage is above the OV setting. Figure 13. Block diagram of BQ25504 circuit . (From [10]) 18 THIS PAGE

  18. Voltage Quality of Grid Connected Wind Turbines

    DEFF Research Database (Denmark)

    Chen, Zhe; Blaabjerg, Frede; Sun, Tao

    2004-01-01

    Grid connected wind turbines may cause quality problems, such as voltage variation and flicker. This paper discusses the voltage variation and flicker emission of grid connected wind turbines with doubly-fed induction generators. A method to compensate flicker by using a voltage source converter...

  19. Manufacturing technology for practical Josephson voltage normals

    International Nuclear Information System (INIS)

    Kohlmann, Johannes; Kieler, Oliver

    2016-01-01

    In this contribution we present the manufacturing technology for the fabrication of integrated superconducting Josephson serial circuits for voltage normals. First we summarize some foundations for Josephson voltage normals and sketch the concept and the setup of the circuits, before we describe the manufacturing technology form modern practical Josephson voltage normals.

  20. 49 CFR 234.221 - Lamp voltage.

    Science.gov (United States)

    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..., Inspection, and Testing Maintenance Standards § 234.221 Lamp voltage. The voltage at each lamp shall be...

  1. Bootstrapped Low-Voltage Analog Switches

    DEFF Research Database (Denmark)

    Steensgaard-Madsen, Jesper

    1999-01-01

    Novel low-voltage constant-impedance analog switch circuits are proposed. The switch element is a single MOSFET, and constant-impedance operation is obtained using simple circuits to adjust the gate and bulk voltages relative to the switched signal. Low-voltage (1-volt) operation is made feasible...

  2. Voltage generators of high voltage high power accelerators

    International Nuclear Information System (INIS)

    Svinin, M.P.

    1981-01-01

    High voltage electron accelerators are widely used in modern radiation installations for industrial purposes. In the near future further increasing of their power may be effected, which enables to raise the efficiency of the radiation processes known and to master new power-consuming production in industry. Improvement of HV generators by increasing their power and efficiency is one of many scientific and engineering aspects the successful solution of which provides further development of these accelerators and their technical parameters. The subject is discussed in detail. (author)

  3. Multiwalled carbon nanotube@a-C@Co9S8 nanocomposites: a high-capacity and long-life anode material for advanced lithium ion batteries

    Science.gov (United States)

    Zhou, Yanli; Yan, Dong; Xu, Huayun; Liu, Shuo; Yang, Jian; Qian, Yitai

    2015-02-01

    A one-dimensional MWCNT@a-C@Co9S8 nanocomposite has been prepared via a facile solvothermal reaction followed by a calcination process. The amorphous carbon layer between Co9S8 and MWCNT acts as a linker to increase the loading of sulfides on MWCNT. When evaluated as anode materials for lithium ion batteries, the MWCNT@a-C@Co9S8 nanocomposite shows the advantages of high capacity and long life, superior to Co9S8 nanoparticles and MWCNT@Co9S8 nanocomposites. The reversible capacity could be retained at 662 mA h g-1 after 120 cycles at 1 A g-1. The efficient synthesis and excellent performances of this nanocomposite offer numerous opportunities for other sulfides as a new anode for lithium ion batteries.A one-dimensional MWCNT@a-C@Co9S8 nanocomposite has been prepared via a facile solvothermal reaction followed by a calcination process. The amorphous carbon layer between Co9S8 and MWCNT acts as a linker to increase the loading of sulfides on MWCNT. When evaluated as anode materials for lithium ion batteries, the MWCNT@a-C@Co9S8 nanocomposite shows the advantages of high capacity and long life, superior to Co9S8 nanoparticles and MWCNT@Co9S8 nanocomposites. The reversible capacity could be retained at 662 mA h g-1 after 120 cycles at 1 A g-1. The efficient synthesis and excellent performances of this nanocomposite offer numerous opportunities for other sulfides as a new anode for lithium ion batteries. Electronic supplementary information (ESI) available: Infrared spectrogram (IR) of glucose treated MWCNT; TEM images of MWCNT@a-C treated by different concentrations of glucose; SEM and TEM images of the intermediate product obtained from the solvothermal reaction between thiourea and Co(Ac)2; EDS spectrum of MWCNT@a-C@Co9S8 composites; SEM and TEM images of MWCNT@Co9S8 nanocomposites obtained without the hydrothermal treatment by glucose; SEM and TEM images of Co9S8 nanoparticles; Galvanostatic discharge-charge profiles and cycling performance of MWCNT@a-C; TEM images

  4. Voltage Management in Unbalanced Low Voltage Networks Using a Decoupled Phase-Tap-Changer Transformer

    DEFF Research Database (Denmark)

    Coppo, Massimiliano; Turri, Roberto; Marinelli, Mattia

    2014-01-01

    The paper studies a medium voltage-low voltage transformer with a decoupled on load tap changer capability on each phase. The overall objective is the evaluation of the potential benefits on a low voltage network of such possibility. A realistic Danish low voltage network is used for the analysis...

  5. 76 FR 70721 - Voltage Coordination on High Voltage Grids; Notice of Staff Workshop

    Science.gov (United States)

    2011-11-15

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. AD12-5-000] Voltage Coordination on High Voltage Grids; Notice of Staff Workshop Take notice that the Federal Energy Regulatory Commission will hold a Workshop on Voltage Coordination on High Voltage Grids on Thursday, December 1, 2011...

  6. Piezo Voltage Controlled Planar Hall Effect Devices.

    Science.gov (United States)

    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.

  7. Capacitor Voltages Measurement and Balancing in Flying Capacitor Multilevel Converters Utilizing a Single Voltage Sensor

    DEFF Research Database (Denmark)

    Farivar, Glen; Ghias, Amer M. Y. M.; Hredzak, Branislav

    2017-01-01

    This paper proposes a new method for measuring capacitor voltages in multilevel flying capacitor (FC) converters that requires only one voltage sensor per phase leg. Multiple dc voltage sensors traditionally used to measure the capacitor voltages are replaced with a single voltage sensor at the ac...... side of the phase leg. The proposed method is subsequently used to balance the capacitor voltages using only the measured ac voltage. The operation of the proposed measurement and balancing method is independent of the number of the converter levels. Experimental results presented for a five-level FC...

  8. Gas insulated substations

    CERN Document Server

    2014-01-01

    This book provides an overview on the particular development steps of gas insulated high-voltage switchgear, and is based on the information given with the editor's tutorial. The theory is kept low only as much as it is needed to understand gas insulated technology, with the main focus of the book being on delivering practical application knowledge. It discusses some introductory and advanced aspects in the meaning of applications. The start of the book presents the theory of Gas Insulated Technology, and outlines reliability, design, safety, grounding and bonding, and factors for choosing GIS. The third chapter presents the technology, covering the following in detail: manufacturing, specification, instrument transformers, Gas Insulated Bus, and the assembly process. Next, the book goes into control and monitoring, which covers local control cabinet, bay controller, control schemes, and digital communication. Testing is explained in the middle of the book before installation and energization. Importantly, ...

  9. Lithium Sulfide (Li2S)/Graphene Oxide Nanospheres with Conformal Carbon Coating as a High-Rate, Long-Life Cathode for Li/S Cells.

    Science.gov (United States)

    Hwa, Yoon; Zhao, Juan; Cairns, Elton J

    2015-05-13

    In recent years, lithium/sulfur (Li/S) cells have attracted great attention as a candidate for the next generation of rechargeable batteries due to their high theoretical specific energy of 2600 W·h kg(-1), which is much higher than that of Li ion cells (400-600 W·h kg(-1)). However, problems of the S cathode such as highly soluble intermediate species (polysulfides Li2Sn, n = 4-8) and the insulating nature of S cause poor cycle life and low utilization of S, which prevents the practical use of Li/S cells. Here, a high-rate and long-life Li/S cell is proposed, which has a cathode material with a core-shell nanostructure comprising Li2S nanospheres with an embedded graphene oxide (GO) sheet as a core material and a conformal carbon layer as a shell. The conformal carbon coating is easily obtained by a unique CVD coating process using a lab-designed rotating furnace without any repetitive steps. The Li2S/GO@C cathode exhibits a high initial discharge capacity of 650 mA·h g(-1) of Li2S (corresponding to the 942 mA·h g(-1) of S) and very low capacity decay rate of only 0.046% per cycle with a high Coulombic efficiency of up to 99.7% for 1500 cycles when cycled at the 2 C discharge rate.

  10. Development of long life pulse power supply for copper vapor laser. Do joki laser yo chojumyo reiki dengen no kaihatsu. ; Saidai shutsuryoku unten oyobi laser hasshin

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, T.; Goto, N.; Nemoto, K. (Central Research Inst. of Electric Power Industry, Tokyo (Japan))

    1990-04-01

    Long life pulse power supply for Cu vapor laser was developed. This is composed of the pulse generation circuit and the pulse compression circuit. Current pulse of 10 mu second pulse width is generated in the pulse generating circuit by switching electric charge on the condensor charged through GTO (gate turn off) thyristors. The pulse compression circuit makes the current pulse fast to 300ms utilizing the difference of inductance at the saturation and the unsaturation on the circuit which uses a reactor having saturable property using a ferromagnetic substance for the core as the magnetic switch. The operation was carried out at the GTO generasting full power. Co base amorphous alloy of low loss was used for the core of saturable inductor and the circuit efficiency of 77% could be obtained by suppressing the heat generation in core even at 4,000Hz operation. The full output power of 8.2kW was possible which corresponds to 100W class laser oscillation. Repeated Cu vapor laser oscillation of 30W succeeded at the condition of 4,000Hz and power supply output of 5.9kW. 7 refs., 21 figs., 8 tabs.

  11. Association of Aging-Related Endophenotypes With Mortality in 2 Cohort Studies: the Long Life Family Study and the Health, Aging and Body Composition Study.

    Science.gov (United States)

    Singh, Jatinder; Schupf, Nicole; Boudreau, Robert; Matteini, Amy M; Prasad, Tanushree; Newman, Anne B; Liu, YongMei; Christensen, Kaare; Kammerer, Candace M

    2015-12-01

    One method by which to identify fundamental biological processes that may contribute to age-related disease and disability, instead of disease-specific processes, is to construct endophenotypes comprising linear combinations of physiological measures. Applying factor analyses methods to phenotypic data (2006-2009) on 28 traits representing 5 domains (cognitive, cardiovascular, metabolic, physical, and pulmonary) from 4,472 US and Danish individuals in 574 pedigrees from the Long Life Family Study (United States and Denmark), we constructed endophenotypes and assessed their relationship with mortality. The most dominant endophenotype primarily reflected the physical activity and pulmonary domains, was heritable, was significantly associated with mortality, and attenuated the association of age with mortality by 24.1%. Using data (1997-1998) on 1,794 Health, Aging and Body Composition Study participants from Memphis, Tennessee, and Pittsburgh, Pennsylvania, we obtained strikingly similar endophenotypes and relationships to mortality. We also reproduced the endophenotype constructs, especially the dominant physical activity and pulmonary endophenotype, within demographic subpopulations of these 2 cohorts. Thus, this endophenotype construct may represent an underlying phenotype related to aging. Additional genetic studies of this endophenotype may help identify genetic variants or networks that contribute to the aging process. © The Author 2015. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  12. A Simple Prelithiation Strategy To Build a High-Rate and Long-Life Lithium-Ion Battery with Improved Low-Temperature Performance.

    Science.gov (United States)

    Liu, Yao; Yang, Bingchang; Dong, Xiaoli; Wang, Yonggang; Xia, Yongyao

    2017-12-22

    Lithium-ion batteries (LIBs) are being used to power the commercial electric vehicles (EVs). However, the charge/discharge rate and life of current LIBs still cannot satisfy the further development of EVs. Furthermore, the poor low-temperature performance of LIBs limits their application in cold climates and high altitude areas. Herein, a simple prelithiation method is developed to fabricate a new LIB. In this strategy, a Li 3 V 2 (PO 4 ) 3 cathode and a pristine hard carbon anode are used to form a primary cell, and the initial Li + extraction from Li 3 V 2 (PO 4 ) 3 is used to prelithiate the hard carbon. Then, the self-formed Li 2 V 2 (PO 4 ) 3 cathode and prelithiated hard carbon anode are used to form a 4 V LIB. The LIB exhibits a maximum energy density of 208.3 Wh kg -1 , a maximum power density of 8291 W kg -1 and a long life of 2000 cycles. When operated at -40 °C, the LIB can keep 67 % capacity of room temperature, which is much better than conventional LIBs. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Design and safety aspect of lead and lead-bismuth cooled long-life small safe fast reactors for various core configurations

    International Nuclear Information System (INIS)

    Zaki, S.; Sekimoto, Hiroshi

    1995-01-01

    Design and safety aspects of long-life small safe fast reactors using liquid lead or lead-bismuth coolant with metallic or nitride fuel are discussed. Neutronic analyses are performed to investigate the effect of core height to diameter ratio (H/D) on design performance of the proposed reactors. All reactors are subjected to the constraint of 12 years operation without refueling and shuffling with constant 150 MWt reactor power and also to the requirement of maximum excess reactivity during burnup to be less than 0.1%Δk. The results show that the pancake design with H/D of ∼2/3 gives the most negative coolant void coefficient under the requirements for excess reactivity. Modified designs with the central region axially fulfilled with fertile material are proposed to improve the coolant void coefficient. Thermal-hydraulic analysis results show the possibility to operate the reactors up to the end of life without changing their orifice pattern, necessary pumping power for the proposed design smaller than the conventional large sodium cooled FBR, and the natural circulation contribution of 25-40% at the normal operating condition. The reactivity feedback coefficients are also estimated and appeared to be negative for all the components including the coolant density coefficient. (author)

  14. Voltage-Gated Calcium Channels

    Science.gov (United States)

    Zamponi, Gerald Werner

    Voltage Gated Calcium Channels is the first comprehensive book in the calcium channel field, encompassing over thirty years of progress towards our understanding of calcium channel structure, function, regulation, physiology, pharmacology, and genetics. This book balances contributions from many of the leading authorities in the calcium channel field with fresh perspectives from risings stars in the area, taking into account the most recent literature and concepts. This is the only all-encompassing calcium channel book currently available, and is an essential resource for academic researchers at all levels in the areas neuroscience, biophysics, and cardiovascular sciences, as well as to researchers in the drug discovery area.

  15. High voltage processing of the SLC polarized electron gun

    International Nuclear Information System (INIS)

    Saez, P.; Clendenin, J.; Garden, C.; Hoyt, E.; Klaisner, L.; Prescott, C.; Schultz, D.; Tang, H.

    1993-04-01

    The SLC polarized electron gun operates at 120 kV with very low dark current to maintain the ultra high vacuum (UHV). This strict requirement protects the extremely sensitive photocathode from contaminants caused by high voltage (HV) activity. Thorough HV processing is thus required x-ray sensitive photographic film, a nanoammeter in series with gun power supply, a radiation meter, a sensitive residual gas analyzer and surface x-ray spectrometry were used to study areas in the gun where HV activity occurred. By reducing the electric field gradients, carefully preparing the HV surfaces and adhering to very strict clean assembly procedures, we found it possible to process the gun so as to reduce both the dark current at operating voltage and the probability of HV discharge. These HV preparation and processing techniques are described

  16. High voltage wide range marx generator design and construction

    International Nuclear Information System (INIS)

    Thompson, J.E.

    1976-01-01

    A wide range, long pulse, Marx generator has been designed and constructed for the purpose of exciting a thermionic electron gun utilized for quasi-cw gas laser medium ionization. The Marx generator has been specifically designed to operate over a voltage range variable from 100 kV to 200 kV into a resistive load of between 83 kΩ and open circuit. This wide operating range, both in voltage and load impedance, was obtained using interstage coupling capacitors to assure overvoltage and subsequent breakdown of the three element spark gap switches used. This paper will discuss the motivation and specific application for the Marx generator and will present the relevant design procedure with particular emphasis on the interstage coupling and triggering techniques employed. Experimental data regarding the measured Marx generator performance will also be presented

  17. A high-voltage triggered pseudospark discharge experiment

    International Nuclear Information System (INIS)

    Ramaswamy, K.; Destler, W.W.; Rodgers, J.

    1996-01-01

    The design and execution of a pulsed high-voltage (350 endash 400 keV) triggered pseudospark discharge experiment is reported. Experimental studies were carried out to obtain an optimal design for stable and reliable pseudospark operation in a high-voltage regime (approx-gt 350 kV). Experiments were performed to determine the most suitable fill gas for electron-beam formation. The pseudospark discharge is initiated by a trigger mechanism involving a flashover between the trigger electrode and hollow cathode housing. Experimental results characterizing the electron-beam energy using the range-energy method are reported. Source size imaging was carried out using an x-ray pinhole camera and a novel technique using Mylar as a witness plate. It was experimentally determined that strong pinching occurred later in time and was associated with the lower-energy electrons. copyright 1996 American Institute of Physics

  18. The electric strength of high-voltage transformers insulation at effect of partial dischargers

    International Nuclear Information System (INIS)

    Khoshravan, E.; Zeraatparvar, A.; Gashimov, A.M.; Mehdizadeh, R.N.

    2001-01-01

    Full text : In paper the change of electric strength of high-voltage transformers insulation at the effect of partial discharges with space charge accumulation was investigated. It is revealed that the effect of partial discharges of insulation materials results the reduction of their pulsing electric strength which can restore the own initial value at releasing of saved charge the volume of a material under condition of absence the ineversible structural changes in it. Researches of high-voltage transformers insulation's non-failure operation conditions show, that at increasing of insulation work time in a strong electrical field the reduction of average breakdown voltages with simultaneous increasing of spread in discharge voltage values takes place. It authentically testifies to reduction of short-time discharge voltage of insulation materials during their electrical aging. As the basic reason of insulation electrical aging the partial discharges occurring in gas cavities inside insulation were considered. It is known that the space charges will be formed in insulation elements of high-voltage devices which effects in dielectrical property of these elements including the electric strength and the space charge formation can occur also at partial discharges in an alternating voltage while the service of high-voltage transformers. In the given work the experiments in revealing separate influence partial discharges in pulsing electric strength of insulation materials at presence and at absence inside them the space charge were spent

  19. Effect of voltage waveform on dielectric barrier discharge ozone production efficiency

    Science.gov (United States)

    Mericam-Bourdet, N.; Kirkpatrick, M. J.; Tuvache, F.; Frochot, D.; Odic, E.

    2012-03-01

    Dielectric barrier discharges (DBDs) are commonly used for gas effluent cleanup and ozone generation. For these applications, the energy efficiency of the discharge is a major concern. This paper reports on investigations carried out on the voltage shape applied to DBD reactor electrodes, aiming to evaluate a possible energy efficiency improvement for ozone production. Two DBD reactor geometries were used: pin-to-pin and cylinder-to-cylinder, both driven either by a bi-directional power supply (voltage rise rate 1 kV/μs) or by a pulsed power supply (voltage rise rate 1 kV/ns). Ozone formed in dry air was measured at the reactor outlet. Special attention was paid to discharge input power evaluation using different methods including instantaneous current-voltage product and transferred charge-applied voltage figures. The charge transferred by the discharges was also correlated to the ozone production. It is shown that, in the case of the DBD reactors under investigation, the applied voltage shape has no influence on the ozone production efficiency. For the considered voltage rise rate, the charge deposit on the dielectric inserted inside the discharge gap is the important factor (as opposed to the voltage shape) governing the efficiency of the discharge - it does this by tailoring the duration of the current peak into the tens of nanosecond range.

  20. Beyond voltage-gated ion channels: Voltage-operated membrane proteins and cellular processes.

    Science.gov (United States)

    Zhang, Jianping; Chen, Xingjuan; Xue, Yucong; Gamper, Nikita; Zhang, Xuan

    2018-04-18

    Voltage-gated ion channels were believed to be the only voltage-sensitive proteins in excitable (and some non-excitable) cells for a long time. Emerging evidence indicates that the voltage-operated model is shared by some other transmembrane proteins expressed in both excitable and non-excitable cells. In this review, we summarize current knowledge about voltage-operated proteins, which are not classic voltage-gated ion channels as well as the voltage-dependent processes in cells for which single voltage-sensitive proteins have yet to be identified. Particularly, we will focus on the following. (1) Voltage-sensitive phosphoinositide phosphatases (VSP) with four transmembrane segments homologous to the voltage sensor domain (VSD) of voltage-gated ion channels; VSPs are the first family of proteins, other than the voltage-gated ion channels, for which there is sufficient evidence for the existence of the VSD domain; (2) Voltage-gated proton channels comprising of a single voltage-sensing domain and lacking an identified pore domain; (3) G protein coupled receptors (GPCRs) that mediate the depolarization-evoked potentiation of Ca 2+ mobilization; (4) Plasma membrane (PM) depolarization-induced but Ca 2+ -independent exocytosis in neurons. (5) Voltage-dependent metabolism of phosphatidylinositol 4,5-bisphosphate (PtdIns[4,5]P 2 , PIP 2 ) in the PM. These recent discoveries expand our understanding of voltage-operated processes within cellular membranes. © 2018 Wiley Periodicals, Inc.

  1. Observability of Low Voltage grids

    DEFF Research Database (Denmark)

    Martin-Loeches, Ruben Sánchez; Iov, Florin; Kemal, Mohammed Seifu

    2017-01-01

    Low Voltage (LV) distribution power grids are experiencing a transformation from a passive to a more active role due to the increasing penetration of distributed generation, heat pumps and electrical vehicles. The first step towards a smarter operation of LV electrical systems is to provide grid ...... an updated state of the art on DSSE-AMI based, adaptive data collection techniques and database management system types. Moreover, the ongoing Danish RemoteGRID project is presented as a realistic case study.......Low Voltage (LV) distribution power grids are experiencing a transformation from a passive to a more active role due to the increasing penetration of distributed generation, heat pumps and electrical vehicles. The first step towards a smarter operation of LV electrical systems is to provide grid....... It becomes unrealistic to provide near real time full observability of the LV grid by applying Distribution System State Estimation (DSSE) utilizing the classical data collection and storage/preprocessing techniques. This paper investigates up-todate the observability problem in LV grids by providing...

  2. A uniform laminar air plasma plume with large volume excited by an alternating current voltage

    Science.gov (United States)

    Li, Xuechen; Bao, Wenting; Chu, Jingdi; Zhang, Panpan; Jia, Pengying

    2015-12-01

    Using a plasma jet composed of two needle electrodes, a laminar plasma plume with large volume is generated in air through an alternating current voltage excitation. Based on high-speed photography, a train of filaments is observed to propagate periodically away from their birth place along the gas flow. The laminar plume is in fact a temporal superposition of the arched filament train. The filament consists of a negative glow near the real time cathode, a positive column near the real time anode, and a Faraday dark space between them. It has been found that the propagation velocity of the filament increases with increasing the gas flow rate. Furthermore, the filament lifetime tends to follow a normal distribution (Gaussian distribution). The most probable lifetime decreases with increasing the gas flow rate or decreasing the averaged peak voltage. Results also indicate that the real time peak current decreases and the real time peak voltage increases with the propagation of the filament along the gas flow. The voltage-current curve indicates that, in every discharge cycle, the filament evolves from a Townsend discharge to a glow one and then the discharge quenches. Characteristic regions including a negative glow, a Faraday dark space, and a positive column can be discerned from the discharge filament. Furthermore, the plasma parameters such as the electron density, the vibrational temperature and the gas temperature are investigated based on the optical spectrum emitted from the laminar plume.

  3. Mobile medium-voltage switching system. Temporary standby power supply in record time; Mobile Mittelspannungsschaltanlage. Vorlaeufige Wiederversorgung in Rekordzeit

    Energy Technology Data Exchange (ETDEWEB)

    Thiery, Matthias; Schwarz, Stefan [Siemens AG, Mannheim (Germany); Wingerter, Dieter [BASF SE, Ludwigshafen (Germany); Doering, Holger [B. Goebel und Sohn GmbH, Asschaffenburg (Germany). Fahrzeugbau

    2011-02-28

    BASF SE Ludwigshafen operates more than 100 medium-voltage switching stations for power supply to its plants. The complexity of the production plants and production method make it necessary to have immediate standby power supply in case of interruption of a medium-voltage switching station. For this purpose, a transportable emergency container was acquired that contains a medium-voltage switching system. Power can be supplied at very short notice, simply by plugging the necessary cable connections. No cranes or other tools are required for installation. The emergency container is designed for use at varying voltage levels and can be transported by road to other BASF sites in Europe. The switching station is a gas-insulated medium-voltage switching station 8DA10 by Siemens, designed for operating voltages of 6, 10, 20, and 35 kW.

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

    Science.gov (United States)

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

    2016-01-01

    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.

  5. Low-crystallinity molybdenum sulfide nanosheets assembled on carbon nanotubes for long-life lithium storage: Unusual electrochemical behaviors and ascending capacities

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiaodan, E-mail: xiaodan_li@yeah.net [State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China ElectricPower University, Beijing, 102206 (China); Wu, Gaoxiang, E-mail: wgxjimmy@126.com [State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China ElectricPower University, Beijing, 102206 (China); Chen, Jiewei, E-mail: kzscjw@126.com [State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China ElectricPower University, Beijing, 102206 (China); Li, Meicheng, E-mail: mcli@ncepu.edu.cn [State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China ElectricPower University, Beijing, 102206 (China); Chongqing Materials Research Institute, Chongqing 400707 (China); Li, Wei, E-mail: wei.li@inl.int [International Iberian Nanotechnology Laboratory (INL), Braga 4715-330 (Portugal); Wang, Tianyue, E-mail: 1355796015@qq.com [State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China ElectricPower University, Beijing, 102206 (China); Jiang, Bing, E-mail: BingJiang@ncepu.edu.cn [State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China ElectricPower University, Beijing, 102206 (China); He, Yue, E-mail: 947667748@qq.com [State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China ElectricPower University, Beijing, 102206 (China); Mai, Liqiang, E-mail: mlq518@whut.edu.cn [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)

    2017-01-15

    Highlights: • Low-crystallinity molybdenum sulfide coated on carbon nanotubes were synthesized. • This anode material has unusual electrochemical behaviors compared to typical MoS{sub 2}. • It exhibits noticable ascending trends in capacity and superior rate performance. • The ascending performance can effectively extend the circulation life of batteries. - Abstract: Low-crystallinity molybdenum sulfide (LCMS, Mo:S = 1:2.75) nanosheets synthesized by a facile and low temperature solvothermal method is now reported. The as-prepared LCMS anode material is composited of MoS{sub 2} layers mixed with amorphous MoS{sub 3}, which leads to an unusual electrochemical process for lithium storage compared to typical MoS{sub 2} anode. The existence of MoS{sub 3} and Mo (VI) provide strong adsorption and binding sites for polar polysulphides, which compels abundant sulfur to turn into new-formed MoS{sub 3} rather than diffuse into electrolyte. To fully utilize this novel electrochemical process, LCMS is decorated on carbon nanotubes, obtaining well-dispersed CNTs@LCMS. As electrode material for lithium storage, CNTs@LCMS exhibits a noticable ascending trend in capacity from 820 mA h g{sup −1} to 1350 mA h g{sup −1} at 100 mA g{sup −1} during 130 cycles. The persistent ascending capacity is ascribed to the increasing lithium storage caused by new-formed MoS{sub 3}, combined with the reduced volume change benifiting from well-dispersed CNTs@LCMS. Furthermore, the ascending performance is proved to be able to effectively extend the circulation life (up to 200%) for lithium-ion batteries by mathematical modeling and calculation. Accordingly, the CNTs@LCMS composite is a promising anode material for long-life lithium-ion batteries.

  6. High voltage load resistor array

    Science.gov (United States)

    Lehmann, Monty Ray [Smithfield, VA

    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.

  7. Theoretical analysis of magnetic sensor output voltage

    International Nuclear Information System (INIS)

    Liu Haishun; Dun Chaochao; Dou Linming; Yang Weiming

    2011-01-01

    The output voltage is an important parameter to determine the stress state in magnetic stress measurement, the relationship between the output voltage and the difference in the principal stresses was investigated by a comprehensive application of magnetic circuit theory, magnetization theory, stress analysis as well as the law of electromagnetic induction, and a corresponding quantitative equation was derived. It is drawn that the output voltage is proportional to the difference in the principal stresses, and related to the angle between the principal stress and the direction of the sensor. This investigation provides a theoretical basis for the principle stresses measurement by output voltage. - Research highlights: → A comprehensive investigation of magnetic stress signal. → Derived a quantitative equation about output voltage and the principal stresses. → The output voltage is proportional to the difference of the principal stresses. → Provide a theoretical basis for the principle stresses measurement.

  8. Voltage-Controlled Floating Resistor Using DDCC

    Directory of Open Access Journals (Sweden)

    M. Kumngern

    2011-04-01

    Full Text Available This paper presents a new simple configuration to realize the voltage-controlled floating resistor, which is suitable for integrated circuit implementation. The proposed resistor is composed of three main components: MOS transistor operating in the non-saturation region, DDCC, and MOS voltage divider. The MOS transistor operating in the non-saturation region is used to configure a floating linear resistor. The DDCC and the MOS transistor voltage divider are used for canceling the nonlinear component term of MOS transistor in the non-saturation region to obtain a linear current/voltage relationship. The DDCC is employed to provide a simple summer of the circuit. This circuit offers an ease for realizing the voltage divider circuit and the temperature effect that includes in term of threshold voltage can be compensated. The proposed configuration employs only 16 MOS transistors. The performances of the proposed circuit are simulated with PSPICE to confirm the presented theory.

  9. Spectrum analysis of a voltage source converter due to semiconductor voltage drops

    DEFF Research Database (Denmark)

    Rasmussen, Tonny Wederberg; Eltouki, Mustafa

    2017-01-01

    It is known that power electronic voltage source converters are non-ideal. This paper presents a state-of-the-art review on the effect of semiconductor voltage drop on the output voltage spectrum, using single-phase H-bridge two-level converter topology with natural sampled pulse width modulation....... The paper describes the analysis of output voltage spectrum, when the semiconductor voltage drop is added. The results of the analysis of the spectral contribution including and excluding semiconductor voltage drop reveal a good agreement between the theoretical results, simulations and laboratory...

  10. Gas target neutron generator studies

    International Nuclear Information System (INIS)

    Chatoorgoon, V.

    1978-01-01

    The need for an intense neutron source for the study of radiation damage on materials has resulted in the proposal of various solid, liquid, and gas targets. Among the gas targets proposed have been the transonic gas target, two types of hypersonic gas target, and the subsonic gas target (SGT). It has been suggested that heat deposition in a subsonic channel might create a gas density step which would constitute an attractive gas target type. The first part of the present study examines this aspect of the SGT and shows that gas density gradients are indeed formed by heat deposition in subsonic flow. The variation of beam voltage, gas density, gas pressure, and gas temperature within the channel have been calculated as functions of the system parameters: beam voltage, beam current, channel diameter, stagnation tank temperature and pressure. The analysis is applicable to any beam particle and target gas. For the case of T + on D 2 , which is relevant to the fusion application, the 14 MeV neutron profiles are presented as a function of system parameters. It is found that the SGT is compatible with concentrated intense source operation. The possibility of instability was investigated in detail using a non-linear analysis which made it possible to follow the complete time development of the SGT. It was found that the SGT is stable against all small perturbations and certain types of large perturbations. It appears that the SGT is the most advantageous type of gas target, operating at a lower mass flow and less severe stagnation tank conditions than the other types. The second part of the thesis examines a problem associated with the straight hypersonic target, the deuterium spill into the tritium port. The regime of practical operation for this target is established. (auth)

  11. Distributed Monitoring of Voltage Collapse Sensitivity Indices

    OpenAIRE

    Simpson-Porco, John W.; Bullo, Francesco

    2016-01-01

    The assessment of voltage stability margins is a promising direction for wide-area monitoring systems. Accurate monitoring architectures for long-term voltage instability are typically centralized and lack scalability, while completely decentralized approaches relying on local measurements tend towards inaccuracy. Here we present distributed linear algorithms for the online computation of voltage collapse sensitivity indices. The computations are collectively performed by processors embedded ...

  12. High voltage investigations for ITER coils

    International Nuclear Information System (INIS)

    Fink, S.; Fietz, W.H.

    2006-01-01

    The superconducting ITER magnets will be excited with high voltage during operation and fast discharge. Because the coils are complex systems the internal voltage distribution can differ to a large extent from the ideal linear voltage distribution. In case of fast excitations internal voltages between conductor and radial plate of a TF coil can be even higher than the terminal voltage of 3.5 kV to ground which appears during a fast discharge without a fault. Hence the determination of the transient voltage distribution is important for a proper insulation co-ordination and will provide a necessary basis for the verification of the individual insulation design and the choice of test voltages and waveforms. Especially the extent of internal overvoltages in case of failures, e. g. malfunction of discharge units and / or arcing is of special interest. Transient calculations for the ITER TF coil system have been performed for fast discharge and fault scenarios to define test voltages for ITER TF. The conductor and radial plate insulation of the ITER TF Model Coil were exposed at room temperature to test voltages derived from the results from these calculations. Breakdown appeared during the highest AC voltage step. A fault scenario for the TF fast discharge system is presented where one fault triggers a second fault, leading to considerable voltage stress. In addition a FEM model of Poloidal Field Coil 3 for the determination of the parameters of a detailed network model is presented in order to prepare detailed investigations of the transient voltage behaviour of the PF coils. (author)

  13. Maximum permissible voltage of YBCO coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Wen, J.; Lin, B.; Sheng, J.; Xu, J.; Jin, Z. [Department of Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China); Hong, Z., E-mail: zhiyong.hong@sjtu.edu.cn [Department of Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China); Wang, D.; Zhou, H.; Shen, X.; Shen, C. [Qingpu Power Supply Company, State Grid Shanghai Municipal Electric Power Company, Shanghai (China)

    2014-06-15

    Highlights: • We examine three kinds of tapes’ maximum permissible voltage. • We examine the relationship between quenching duration and maximum permissible voltage. • Continuous I{sub c} degradations under repetitive quenching where tapes reaching maximum permissible voltage. • The relationship between maximum permissible voltage and resistance, temperature. - Abstract: 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 (I{sub c}) degradation or burnout. In this research, the time of quenching process is changed and voltage is raised until the I{sub c} 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.

  14. Low-Voltage Switched-Capacitor Circuits

    DEFF Research Database (Denmark)

    Bidari, E.; Keskin, M.; Maloberti, F.

    1999-01-01

    Switched-capacitor stages are described which can function with very low (typically 1 V) supply voltages, without using voltage boosting or switched op-amps. Simulations indicate that high performance may be achieved using these circuits in filter or data converter applications.......Switched-capacitor stages are described which can function with very low (typically 1 V) supply voltages, without using voltage boosting or switched op-amps. Simulations indicate that high performance may be achieved using these circuits in filter or data converter applications....

  15. Voltage-dependent gating in a "voltage sensor-less" ion channel.

    Directory of Open Access Journals (Sweden)

    Harley T Kurata

    2010-02-01

    Full Text Available The voltage sensitivity of voltage-gated cation channels is primarily attributed to conformational changes of a four transmembrane segment voltage-sensing domain, conserved across many levels of biological complexity. We have identified a remarkable point mutation that confers significant voltage dependence to Kir6.2, a ligand-gated channel that lacks any canonical voltage-sensing domain. Similar to voltage-dependent Kv channels, the Kir6.2[L157E] mutant exhibits time-dependent activation upon membrane depolarization, resulting in an outwardly rectifying current-voltage relationship. This voltage dependence is convergent with the intrinsic ligand-dependent gating mechanisms of Kir6.2, since increasing the membrane PIP2 content saturates Po and eliminates voltage dependence, whereas voltage activation is more dramatic when channel Po is reduced by application of ATP or poly-lysine. These experiments thus demonstrate an inherent voltage dependence of gating in a "ligand-gated" K+ channel, and thereby provide a new view of voltage-dependent gating mechanisms in ion channels. Most interestingly, the voltage- and ligand-dependent gating of Kir6.2[L157E] is highly sensitive to intracellular [K+], indicating an interaction between ion permeation and gating. While these two key features of channel function are classically dealt with separately, the results provide a framework for understanding their interaction, which is likely to be a general, if latent, feature of the superfamily of cation channels.

  16. Gas turbine

    International Nuclear Information System (INIS)

    Yang, Ok Ryong

    2004-01-01

    This book introduces gas turbine cycle explaining general thing of gas turbine, full gas turbine cycle, Ericson cycle and Brayton cycle, practical gas turbine cycle without pressure loss, multiaxial type gas turbine cycle and special gas turbine cycle, application of basic theory on a study on suction-cooling gas turbine cycle with turbo-refrigerating machine using the bleed air, and general performance characteristics of the suction-cooling gas turbine cycle combined with absorption-type refrigerating machine.

  17. Excitation of voltage oscillations in an induction voltage adder

    Directory of Open Access Journals (Sweden)

    Nichelle Bruner

    2009-07-01

    Full Text Available 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.

  18. Three-phase current transformer rectifier sets. High-voltage power supplies for difficult conditions in electrostatic precipitators

    Energy Technology Data Exchange (ETDEWEB)

    Stackelberg, Josef von [Rico-Werk Eiserlo und Emmrich GmbH, Toenisvorst (Germany)

    2013-04-01

    The precipitation rate of electrostatic precipitators (ESP) highly depends on the consistency of waste gas. Among other things, electrical conductivity plays an important role as well as the ability of particles to be electrically charged or ionised. Within certain limits, common ESPs are able to clean waste gas satisfactorily. If the dust attributes exceed these limits, more sophisticated technical solutions are required in the ESP to meet the demands for the gas cleaning equipment. In these cases, a three phase transformer rectifier system offers an alternative to the conventional single phase system, as it delivers a smooth direct current voltage over a wide voltage range. (orig.)

  19. The effect of external visible light on the breakdown voltage of a long discharge tube

    Science.gov (United States)

    Shishpanov, A. I.; Ionikh, Yu. Z.; Meshchanov, A. V.

    2016-06-01

    The breakdown characteristics of a discharge tube with a configuration typical of gas-discharge light sources and electric-discharge lasers (a so-called "long discharge tube") filled with argon or helium at a pressure of 1 Torr have been investigated. A breakdown has been implemented using positive and negative voltage pulses with a linear leading edge having a slope dU/ dt ~ 10-107 V/s. Visible light from an external source (halogen incandescent lamp) is found to affect the breakdown characteristics. The dependences of the dynamic breakdown voltage of the tube on dU/ dt and on the incident light intensity are measured. The breakdown voltage is found to decrease under irradiation of the high-voltage anode of the tube in a wide range of dU/ dt. A dependence of the effect magnitude on the light intensity and spectrum is obtained. Possible physical mechanisms of this phenomenon are discussed.

  20. Calculation of Onset Voltage of Sliding Discharge over a Dielectric Barrier

    Directory of Open Access Journals (Sweden)

    Abdel-Salam Mazen

    2016-01-01

    Full Text Available This paper is aimed at calculating the onset voltage of a sliding discharge established between two electrodes at the upper and bottom surfaces of a dielectric barrier plate; named sliding dielectric barrier discharge (SDBD driven by AC voltage during negative half cycle. The onset voltage is based on the condition of self-sustenance of avalanche growth in the vicinity of the stressed electrode. This calls at first for calculation of the electric field in the vicinity of stressed electrode. The dependency of onset voltage on the thickness and permittivity of the dielectric barrier as well as the thickness of the stressed electrode and the inter-electrode spacing between the stressed and ground electrodes is investigated. The obtained results are discussed in the light of gas discharge physics.

  1. Study on the construction and its operating characteristics of Marx high voltage pulse generator

    International Nuclear Information System (INIS)

    Chung, W.K.; Yook, C.C.

    1984-01-01

    This study is to investigate the operating characteristics of a Marx high voltage pulse generator, which is designed and fabricated for the purpose of constructing a linear theta-pinch plasma generating facility. The Marx generator consists of a 2 kJ capacitor bank of maximum output voltage of 200kV, a set of main spark switch, a triggring system, and high voltage charging power supply. The experimental results show that the operating characteristics of the generator can be controlled through varying nitrogen pressure as a filling gas. The output pulse of the generator is achieved close to the estimated voltage with the rise time of 3*m seconds. The stability of the generator is also very satisfactory within operating range of main spark switch. (Author)

  2. High voltage pulse system for the streamer chamber supply of the GIBS spectrometer

    International Nuclear Information System (INIS)

    Aksinenko, V.D.; Glagoleva, N.S.; Dement'ev, E.A.; Kaminskij, N.I.; Matyushin, A.T.; Matyushin, V.T.; Rozhnyatovskaya, S.A.; Ryakhovskij, V.N.; Nurgozhin, N.N.; Khusainov, E.K.

    1987-01-01

    Results of development and testing of high voltage pulse system HVPS for the streamer chamber supply of the GIBS spectrometer are presented. HVPS consists of the following basic blocks: nanosecond pulse high voltage generator, high voltage charging supply, trigger generator, chamber parameter control devices, gas-oil vacuuming supply systems, auxiliary and fire-prevention devices. The system blocks are described. Experimental results of HVPC testing are presented. HVPC provides a reliable (10 5 operations) of streamer chamber supply with high voltage pulse parameters: amplitude - 500 kV, amplitude instability (0.5-1.5)%, pulse duration - 12 ns, delay time - 500 ns, delay instability (2.5-5)%, mean frequency of output a signals - 0.1 Hz

  3. Mapping of Residues Forming the Voltage Sensor of the Voltage-Dependent Anion-Selective Channel

    Science.gov (United States)

    Thomas, Lorie; Blachly-Dyson, Elizabeth; Colombini, Marco; Forte, Michael

    1993-06-01

    Voltage-gated ion-channel proteins contain "voltage-sensing" domains that drive the conformational transitions between open and closed states in response to changes in transmembrane voltage. We have used site-directed mutagenesis to identify residues affecting the voltage sensitivity of a mitochondrial channel, the voltage-dependent anion-selective channel (VDAC). Although charge changes at many sites had no effect, at other sites substitutions that increased positive charge also increased the steepness of voltage dependance and substitutions that decreased positive charge decreased voltage dependance by an appropriate amount. In contrast to the plasma membrane K^+ and Na^+ channels, these residues are distributed over large parts of the VDAC protein. These results have been used to define the conformational transitions that accompany voltage gating of an ion channel. This gating mechanism requires the movement of large portions of the VDAC protein through the membrane.

  4. Baking of tandem accelerator tube by low voltage arc discharge

    International Nuclear Information System (INIS)

    Nakajima, Yutaka

    1982-01-01

    In designing the accelerating tube for a static tandem accelerator in Kyushu University, the basic policy was as described below: individual unit composing the accelerating tube should fully withstand the electric field of 2 MV/m, and electric discharge must not be propagated from one unit to the adjacent unit when these are assembled to the accelerating tube. The accelerating tube units are each 25 cm in length, and both high and low energy sides are composed of 20 units, respectively. Although about 10 -9 Torr vacuum was obtained at the both ends of the accelerating tube by baking the tube at 300 to 350 deg C with electric heaters wound outside the tube in the conventional method, vast outgas was generated, which decreased vacuum by two or three figures if breakdown occurred through the intermediary of outgas. As a method of positively outgassing and cleaning the electrodes inside the accelerating tube, it was attempted to directly bake all the electrodes in the accelerating tube by causing strong arc discharge flowing H 2 gas in the tube. As a result of considering the conditions for this method, the low voltage arc discharge was employed using oxide cathodes. Thus, after implementing 10A arc discharge for several hours, the voltage was able to be raised to 10 MV almost immediately after the vacuum recovery, and further, after another conditioning for several hours, it was successful to raise voltage up to 11 MV. (Wakatsuki, Y.)

  5. Prototype high voltage bushing: Configuration to its operational demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Sejal, E-mail: sshah@iter-india.org [ITER-India, Institute for Plasma Research, Bhat, Gandhinagar 382428 (India); Sharma, D. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India); Parmar, D.; Tyagi, H.; Joshi, K.; Shishangiya, H.; Bandyopadhyay, M.; Rotti, C.; Chakraborty, A. [ITER-India, Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

    2016-12-15

    High Voltage Bushing (HVB) is the key component of Diagnostic Neutral Beam (DNB) system of ITER as it provides access to high voltage electrical, hydraulic, gas and diagnostic feedlines to the beam source with isolation from grounded vessel. HVB also provides primary vacuum confinement for the DNB system. Being Safety Important Class (SIC) component of ITER, it involves several configurational, technological and operational challenges. To ensure its operational performance & reliability, particularly electrostatic behavior, half scale down Prototype High Voltage Bushing (PHVB) is designed considering same design criteria of DNB HVB. Design optimization has been carried out followed by finite element (FE) analysis to obtain DNB HVB equivalent electric stress on different parts of PHVB, taking into account all design, manufacturing & space constraints. PHVB was tested up to 60 kV without breakdown, which validates its design for the envisaged operation of 50 kV DC. This paper presents the design of PHVB, FEA validation, manufacturing constraints, experimental layout with interfacing auxiliary systems and operational results related to functional performance.

  6. Autonomous Voltage Oscillations in a Direct Methanol Fuel Cell

    International Nuclear Information System (INIS)

    Nogueira, Jéssica A.; Peña Arias, Ivonne K.; Hanke-Rauschenbach, Richard; Vidakovic-Koch, Tanja; Varela, Hamilton; Sundmacher, Kai

    2016-01-01

    Proton exchange membrane fuel cells fed with H_2/CO mixtures at the anode have a considerably lower performance than fuel cells fed with pure hydrogen. However, when operated in an autonomous oscillatory regime, the overall voltage loss decreases due to a self-cleaning mechanism. Another molecule, also widely used as feed in the fuel cell and susceptible to kinetic instabilities, is methanol. To the best of our knowledge, there are no reports on autonomous voltage oscillations in the direct methanol fuel cell (DMFC). The purpose of this work was to explore if such instabilities also occur in the DMFC system. Initially, half-cell experiments with a gas diffusion electrode were performed. Then, a DMFC was operated under current control and studied by means of electrochemical impedance spectroscopy. The half-cell measurements revealed that the induction period for oscillations depends on the mass transfer conditions, where on stagnant electrode the induction time was shorter than in the case of forced convection. The DMFC showed also autonomous voltage oscillations above a certain threshold current. The results obtained by electrochemical impedance spectroscopy give evidence of a negative differential resistance in the fuel cell, hitherto not described in the literature, which can be related to the appearance of oscillations during galvanostatic methanol electro-oxidation. These results open the possibility to evaluate the performance of low-temperature fuel cells fed with carbon-containing fuels under oscillatory operating conditions.

  7. Numerical investigation of the effect of driving voltage pulse shapes on the characteristics of low-pressure argon dielectric barrier discharge

    International Nuclear Information System (INIS)

    Eslami, E.; Barjasteh, A.; Morshedian, N.

    2015-01-01

    In this work, we numerically compare the effect of a sinusoidal, triangular, and rectangular pulsed voltage profile on the calculated particle production, electric current, and gas voltage in a dielectric barrier discharge. The total argon gas pressure of 400 Pa, the distance between dielectrics of 5 mm, the dielectric thickness of 0.7 mm, and the temperature of T = 300 K were considered as input parameters. The different driving voltage pulse shapes (triangular, rectangular, and sinusoidal) are considered as applied voltage with a frequency of 7 kHz and an amplitude of 700 V peak to peak. It is shown that applying a rectangular voltage, as compared with a sinusoidal or triangle voltage, increases the current peak, while the peak width is decreased. Higher current density is related to high production of charged particles, which leads to the generation of some highly active species, such as Ar* (4s level), and Ar** (4p level) in the gap

  8. Protective role of the apolipoprotein E2 allele in age-related disease traits and survival: evidence from the Long Life Family Study.

    Science.gov (United States)

    Kulminski, Alexander M; Raghavachari, Nalini; Arbeev, Konstantin G; Culminskaya, Irina; Arbeeva, Liubov; Wu, Deqing; Ukraintseva, Svetlana V; Christensen, Kaare; Yashin, Anatoliy I

    2016-11-01

    The apolipoprotein E (apoE) is a classic example of a gene exhibiting pleiotropism. We examine potential pleiotropic associations of the apoE2 allele in three biodemographic cohorts of long-living individuals, offspring, and spouses from the Long Life Family Study, and intermediate mechanisms, which can link this allele with age-related phenotypes. We focused on age-related macular degeneration, bronchitis, asthma, pneumonia, stroke, creatinine, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol, diseases of heart (HD), cancer, and survival. Our analysis detected favorable associations of the ε2 allele with lower LDL-C levels, lower risks of HD, and better survival. The ε2 allele was associated with LDL-C in each gender and biodemographic cohort, including long-living individuals, offspring, and spouses, resulting in highly significant association in the entire sample (β = -7.1, p = 6.6 × 10 -44 ). This allele was significantly associated with HD in long-living individuals and offspring (relative risk [RR] = 0.60, p = 3.1 × 10 -6 ) but this association was not mediated by LDL-C. The protective effect on survival was specific for long-living women but it was not explained by LDL-C and HD in the adjusted model (RR = 0.70, p = 2.1 × 10 -2 ). These results show that ε2 allele may favorably influence LDL-C, HD, and survival through three mechanisms. Two of them (HD- and survival-related) are pronounced in the long-living parents and their offspring; the survival-related mechanism is also sensitive to gender. The LDL-C-related mechanism appears to be independent of these factors. Insights into mechanisms linking ε2 allele with age-related phenotypes given biodemographic structure of the population studied may benefit translation of genetic discoveries to health care and personalized medicine.

  9. A feasibility study on long-life reduced-moderation water reactor with highly protected Pu breeding by doping with minor actinides

    International Nuclear Information System (INIS)

    Hamase, Erina; Damian, Frederic; Poinot-salanon, Christine; Saito, Masaki; Sagara, Hiroshi; Han, Chi Young

    2013-01-01

    Highlights: ► The present paper is focused on a reduced-moderation water reactor. ►237 Np or 241 Am was doped into the inner blanket. ►238 Pu transmuted from MA works as a fissionable nuclide. ► It also contributes to increasing the proliferation resistance of Pu. ► Long-life core and highly protected Pu breeding were simultaneously achieved. - Abstract: The present paper is focused on the feasibility of reduced-moderation water reactor (RMWR) which could simultaneously achieve the extension of core life-time, and highly protected plutonium (Pu) breeding performance with short compound system doubling time (CSDT) by neptunium-237 ( 237 Np) or americium-241 ( 241 Am) doping of the inner blanket of the RMWR. As a preliminary analysis of the RMWR, a simplified fuel pin configuration was analyzed. In case of 60% doping of 237 Np and 241 Am in the inner blanket, the maximum available effective full power days (EFPDs) were much longer and were about 15,100 and 14,200 EFPDs, respectively. For the proliferation resistance of Pu produced in the blanket, the total Pu in the inner and lower/upper blanket was below the practically unusable criterion for an explosive device proposed by Pellaud, and was technically unfeasible for high-technology hypothetical nuclear explosive devices (HNEDs) proposed by Kessler and Kimura. The protected Pu breeding performance was analyzed and in case of 60% doping of 237 Np and 241 Am, CSDT was short by approximately 40 and 50 years. Therefore, the feasibility of RMWR was shown which could simultaneously achieve the extension of core life-time and have highly protected Pu breeding performance with short CSDT by doping the inner blanket with minor actinides (MAs). The objective of this study was thus to evaluate the performance of the concept with respect to the core life-time, proliferation resistance of Pu and CSDT. The technological feasibility of such core concept will have to be evaluated by further dedicated analyses

  10. Voltage stability in low voltage microgrids in aspects of active and reactive power demand

    Directory of Open Access Journals (Sweden)

    Parol Mirosław

    2016-03-01

    Full Text Available Low voltage microgrids are autonomous subsystems, in which generation, storage and power and electrical energy consumption appear. In the paper the main attention has been paid to the voltage stability issue in low voltage microgrid for different variants of its operation. In the introduction a notion of microgrid has been presented, and also the issue of influence of active and reactive power balance on node voltage level has been described. Then description of voltage stability issue has been presented. The conditions of voltage stability and indicators used to determine voltage stability margin in the microgrid have been described. Description of the low voltage test microgrid, as well as research methodology along with definition of considered variants of its operation have been presented further. The results of exemplary calculations carried out for the daily changes in node load of the active and reactive power, i.e. the voltage and the voltage stability margin indexes in nodes have been presented. Furthermore, the changes of voltage stability margin indexes depending on the variant of the microgrid operation have been presented. Summary and formulation of conclusions related to the issue of voltage stability in microgrids have been included at the end of the paper.

  11. Influence of current limitation on voltage stability with voltage sourced converter HVDC

    DEFF Research Database (Denmark)

    Zeni, Lorenzo; Jóhannsson, Hjörtur; Hansen, Anca Daniela

    2013-01-01

    A first study of voltage stability with relevant amount of Voltage Sourced Converter based High Voltage Direct Current (VSC-HVDC) transmission is presented, with particular focus on the converters’ behaviour when reaching their rated current. The detrimental effect of entering the current...

  12. Voltage-Sensitive Load Controllers for Voltage Regulation and Increased Load Factor in Distribution Systems

    DEFF Research Database (Denmark)

    Douglass, Philip James; Garcia-Valle, Rodrigo; Østergaard, Jacob

    2014-01-01

    This paper presents a novel controller design for controlling appliances based on local measurements of voltage. The controller finds the normalized voltage deviation accounting for the sensitivity of voltage measurements to appliance state. The controller produces a signal indicating desired pow...

  13. On-site voltage measurement with capacitive sensors on high voltage systems

    NARCIS (Netherlands)

    Wu, L.; Wouters, P.A.A.F.; Heesch, van E.J.M.; Steennis, E.F.

    2011-01-01

    In Extra/High-Voltage (EHV/HV) power systems, over-voltages occur e.g. due to transients or resonances. At places where no conventional voltage measurement devices can be installed, on-site measurement of these occurrences requires preferably non intrusive sensors, which can be installed with little

  14. 76 FR 72203 - Voltage Coordination on High Voltage Grids; Notice of Reliability Workshop Agenda

    Science.gov (United States)

    2011-11-22

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. AD12-5-000] Voltage Coordination on High Voltage Grids; Notice of Reliability Workshop Agenda As announced in the Notice of Staff..., from 9 a.m. to 4:30 p.m. to explore the interaction between voltage control, reliability, and economic...

  15. Modeling and Simulation of Low Voltage Arcs

    NARCIS (Netherlands)

    Ghezzi, L.; Balestrero, A.

    2010-01-01

    Modeling and Simulation of Low Voltage Arcs is an attempt to improve the physical understanding, mathematical modeling and numerical simulation of the electric arcs that are found during current interruptions in low voltage circuit breakers. An empirical description is gained by refined electrical

  16. Reduced Voltage Scaling in Clock Distribution Networks

    Directory of Open Access Journals (Sweden)

    Khader Mohammad

    2009-01-01

    Full Text Available We propose a novel circuit technique to generate a reduced voltage swing (RVS signals for active power reduction on main buses and clocks. This is achieved without performance degradation, without extra power supply requirement, and with minimum area overhead. The technique stops the discharge path on the net that is swinging low at a certain voltage value. It reduces active power on the target net by as much as 33% compared to traditional full swing signaling. The logic 0 voltage value is programmable through control bits. If desired, the reduced-swing mode can also be disabled. The approach assumes that the logic 0 voltage value is always less than the threshold voltage of the nMOS receivers, which eliminate the need of the low to high voltage translation. The reduced noise margin and the increased leakage on the receiver transistors using this approach have been addressed through the selective usage of multithreshold voltage (MTV devices and the programmability of the low voltage value.

  17. The LMF triaxial MITL voltage adder system

    International Nuclear Information System (INIS)

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

    1992-01-01

    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

  18. Time isolation high-voltage impulse generator

    International Nuclear Information System (INIS)

    Chodorow, A.M.

    1975-01-01

    Lewis' high-voltage impulse generator is analyzed in greater detail, demonstrating that voltage between adjacent nodes can be equalized by proper selection of parasitic impedances. This permits improved TEM mode propagation to a matched load, with more faithful source waveform preservation

  19. High-voltage engineering and testing

    CERN Document Server

    Ryan, Hugh M

    2013-01-01

    This 3rd edition of High Voltage Engineering Testing describes strategic developments in the field and reflects on how they can best be managed. All the key components of high voltage and distribution systems are covered including electric power networks, UHV and HV. Distribution systems including HVDC and power electronic systems are also considered.

  20. Improving transition voltage spectroscopy of molecular junctions

    DEFF Research Database (Denmark)

    Markussen, Troels; Chen, Jingzhe; Thygesen, Kristian Sommer

    2011-01-01

    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...

  1. Reducing Ripple In A Switching Voltage Regulator

    Science.gov (United States)

    Paulkovich, John; Rodriguez, G. Ernest

    1994-01-01

    Ripple voltage in output of switching voltage regulator reduced substantially by simple additional circuitry adding little to overall weight and size of regulator. Heretofore, additional filtering circuitry needed to obtain comparable reductions in ripple typically as large and heavy as original regulator. Current opposing ripple current injected into filter capacitor.

  2. Wide-range voltage modulation

    International Nuclear Information System (INIS)

    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-μs wide pulse with a rise time of less than 1 μs, 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

  3. Device for measurement of gas mass flow. Einrichtung zur Gasmassenstrommessung

    Energy Technology Data Exchange (ETDEWEB)

    Sass, W

    1989-09-28

    The invention is concerned with a device for the measurement of gas mass flow, particularly measuring air mass flow for vehicles with internal combustion engines, with a measurement bridge, in one branch of which a gas flow resistance, particularly a hot film sensor, with gas flowing round it, is connected in series with a measurement resistance and in another branch of which a compensation resistance measuring the gas temperature is connected in series with a fixed resistor, where the bridge differential voltage is measured in the zero branch of the measuring bridge and a control parameter is produced from this, in order to control a transistor valve situated in the bridge supply path of a DC voltage source via its control electrode until the bridge is balanced, and where the voltage at the measurement resistance after the bridge is balanced is used as a measure of the gas mass flow. In order to obtain exact results of measurement in spite of relatively high interference noise from the cables, it is proposed that an increased supply DC voltage appreciably decreasing the occurring interference noise from the cables should be produced from a small DC voltage and that the output of the DC/DC voltage converter should be connected to the control electrode of the transistor valve, so that the control parameter for the control electrode is derived from the raised DC supply voltage through reducers depending on the gas flow.

  4. Practical considerations in voltage stability assessment

    Energy Technology Data Exchange (ETDEWEB)

    Kundur, P; Gao, B [Powertech Labs. Inc., Surrey, BC (Canada)

    1994-12-31

    This paper deals with some of the most important practical issues related to voltage stability assessment of large practical systems. A brief discussion of the practical aspects of voltage stability problem and prevention of voltage instability is given first, followed by descriptions of different analytical techniques and tools for voltage stability analysis. Presentations of analytical tools is focused on the VSTAB program which incorporates the modal analysis, continuation power flow, and shortest distance to instability techniques, Finally, an example case study of a practical large system is presented. The case study illustrates how modal analysis is used to determine the most effective load shedding scheme for preventing voltage instability. (author) 15 refs., 2 figs., 2 tabs.

  5. Voltage-assisted polymer wafer bonding

    International Nuclear Information System (INIS)

    Varsanik, J S; Bernstein, J J

    2012-01-01

    Polymer wafer bonding is a widely used process for fabrication of microfluidic devices. However, best practices for polymer bonds do not achieve sufficient bond strength for many applications. By applying a voltage to a polymer bond in a process called voltage-assisted bonding, bond strength is shown to improve dramatically for two polymers (Cytop™ and poly(methyl methacrylate)). Several experiments were performed to provide a starting point for further exploration of this technique. An optimal voltage range is experimentally observed with a reduction in bonding strength at higher voltages. Additionally, voltage-assisted bonding is shown to reduce void diameter due to bond defects. An electrostatic force model is proposed to explain the improved bond characteristics. This process can be used to improve bond strength for most polymers. (paper)

  6. Voltage-gated lipid ion channels

    DEFF Research Database (Denmark)

    Blicher, Andreas; Heimburg, Thomas Rainer

    2013-01-01

    Synthetic lipid membranes can display channel-like ion conduction events even in the absence of proteins. We show here that these events are voltage-gated with a quadratic voltage dependence as expected from electrostatic theory of capacitors. To this end, we recorded channel traces and current...... histograms in patch-experiments on lipid membranes. We derived a theoretical current-voltage relationship for pores in lipid membranes that describes the experimental data very well when assuming an asymmetric membrane. We determined the equilibrium constant between closed and open state and the open...... probability as a function of voltage. The voltage-dependence of the lipid pores is found comparable to that of protein channels. Lifetime distributions of open and closed events indicate that the channel open distribution does not follow exponential statistics but rather power law behavior for long open times...

  7. Non-contact current and voltage sensor

    Science.gov (United States)

    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.

  8. Coordinated Voltage Control of Active Distribution Network

    Directory of Open Access Journals (Sweden)

    Xie Jiang

    2016-01-01

    Full Text Available This paper presents a centralized coordinated voltage control method for active distribution network to solve off-limit problem of voltage after incorporation of distributed generation (DG. The proposed method consists of two parts, it coordinated primal-dual interior point method-based voltage regulation schemes of DG reactive powers and capacitors with centralized on-load tap changer (OLTC controlling method which utilizes system’s maximum and minimum voltages, to improve the qualified rate of voltage and reduce the operation numbers of OLTC. The proposed coordination has considered the cost of capacitors. The method is tested using a radial edited IEEE-33 nodes distribution network which is modelled using MATLAB.

  9. Reactive power dispatch considering voltage stability with seeker optimization algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Chaohua; Chen, Weirong; Zhang, Xuexia [The School of Electrical Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Zhu, Yunfang [Department of Computer and Communication Engineering, E' mei Campus, Southwest Jiaotong University, E' mei 614202 (China)

    2009-10-15

    Optimal reactive power dispatch (ORPD) has a growing impact on secure and economical operation of power systems. This issue is well known as a non-linear, multi-modal and multi-objective optimization problem where global optimization techniques are required in order to avoid local minima. In the last decades, computation intelligence-based techniques such as genetic algorithms (GAs), differential evolution (DE) algorithms and particle swarm optimization (PSO) algorithms, etc., have often been used for this aim. In this work, a seeker optimization algorithm (SOA) based method is proposed for ORPD considering static voltage stability and voltage deviation. The SOA is based on the concept of simulating the act of human searching where search direction is based on the empirical gradient by evaluating the response to the position changes and step length is based on uncertainty reasoning by using a simple Fuzzy rule. The algorithm's performance is studied with comparisons of two versions of GAs, three versions of DE algorithms and four versions of PSO algorithms on the IEEE 57 and 118-bus power systems. The simulation results show that the proposed approach performed better than the other listed algorithms and can be efficiently used for the ORPD problem. (author)

  10. Reliability of supply of switchgear for auxiliary low voltage in substations extra high voltage to high voltage

    Directory of Open Access Journals (Sweden)

    Perić Dragoslav M.

    2015-01-01

    Full Text Available Switchgear for auxiliary low voltage in substations (SS of extra high voltages (EHV to high voltage (HV - SS EHV/HV kV/kV is of special interest for the functioning of these important SS, as it provides a supply for system of protection and other vital functions of SS. The article addresses several characteristic examples involving MV lines with varying degrees of independence of their supply, and the possible application of direct transformation EHV/LV through special voltage transformers. Auxiliary sources such as inverters and diesel generators, which have limited power and expensive energy, are also used for the supply of switchgear for auxiliary low voltage. Corresponding reliability indices are calculated for all examples including mean expected annual engagement of diesel generators. The applicability of certain solutions of switchgear for auxiliary low voltage SS EHV/HV, taking into account their reliability, feasibility and cost-effectiveness is analyzed too. In particular, the analysis of applications of direct transformation EHV/LV for supply of switchgear for auxiliary low voltage, for both new and existing SS EHV/HV.

  11. Exciplex-triplet energy transfer: A new method to achieve extremely efficient organic light-emitting diode with external quantum efficiency over 30% and drive voltage below 3 V

    Science.gov (United States)

    Seo, Satoshi; Shitagaki, Satoko; Ohsawa, Nobuharu; Inoue, Hideko; Suzuki, Kunihiko; Nowatari, Hiromi; Yamazaki, Shunpei

    2014-04-01

    A novel approach to enhance the power efficiency of an organic light-emitting diode (OLED) by employing energy transfer from an exciplex to a phosphorescent emitter is reported. It was found that excitation energy of an exciplex formed between an electron-transporting material with a π-deficient quinoxaline moiety and a hole-transporting material with aromatic amine structure can be effectively transferred to a phosphorescent iridium complex in an emission layer of a phosphorescent OLED. Moreover, such an exciplex formation increases quantum efficiency and reduces drive voltage. A highly efficient, low-voltage, and long-life OLED based on this energy transfer is also demonstrated. This OLED device exhibited extremely high external quantum efficiency of 31% even without any attempt to enhance light outcoupling and also achieved a low drive voltage of 2.8 V and a long lifetime of approximately 1,000,000 h at a luminance of 1,000 cd/m2.

  12. A Novel Index for Online Voltage Stability Assessment Based on Correlation Characteristic of Voltage Profiles

    Directory of Open Access Journals (Sweden)

    M. R. Aghamohammadi

    2011-06-01

    Full Text Available Abstract: Voltage instability is a major threat for security of power systems. Preserving voltage security margin at a certain limit is a vital requirement for today’s power systems. Assessment of voltage security margin is a challenging task demanding sophisticated indices. In this paper, for the purpose of on line voltage security assessment a new index based on the correlation characteristic of network voltage profile is proposed. Voltage profile comprising all bus voltages contains the effect of network structure, load-generation patterns and reactive power compensation on the system behaviour and voltage security margin. Therefore, the proposed index is capable to clearly reveal the effect of system characteristics and events on the voltage security margin. The most attractive feature for this index is its fast and easy calculation from synchronously measured voltage profile without any need to system modelling and simulation and without any dependency on network size. At any instant of system operation by merely measuring network voltage profile and no further simulation calculation this index could be evaluated with respect to a specific reference profile. The results show that the behaviour of this index with respect to the change in system security is independent of the selected reference profile. The simplicity and easy calculation make this index very suitable for on line application. The proposed approach has been demonstrated on IEEE 39 bus test system with promising results showing its effectiveness and applicability.

  13. Novel Voltage limiting concept for avalance breakdown protection

    NARCIS (Netherlands)

    Ruijs, L.C.H.; Bezooijen, van A.; Mahmoudi, R.; Roermund, van A.H.M.

    2006-01-01

    Destructive over-voltage breakdown of cellular phone power transistors is prevented by using a new voltage-limiting concept. The output voltage is detected by an avalanche-based detector, and limited by decreasing the output power when needed. The voltage detector contains a low voltage bipolar NPN

  14. Fuel Cell/Electrochemical Cell Voltage Monitor

    Science.gov (United States)

    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.

  15. High voltage electricity installations a planning perspective

    CERN Document Server

    Jay, Stephen Andrew

    2006-01-01

    The presence of high voltage power lines has provoked widespread concern for many years. High Voltage Electricity Installations presents an in-depth study of policy surrounding the planning of high voltage installations, discussing the manner in which they are percieved by the public, and the associated environmental issues. An analysis of these concerns, along with the geographical, environmental and political influences that shape their expression, is presented. Investigates local planning policy in an area of the energy sector that is of highly topical environmental and public concern Cover

  16. Investigation of voltage swell mitigation using STATCOM

    International Nuclear Information System (INIS)

    Razak, N A Abdul; Jaafar, S; Hussain, I S

    2013-01-01

    STATCOM is one of the best applications of a self commutated FACTS device to control power quality problems in the distribution system. This project proposed a STATCOM model with voltage control mechanism. DQ transformation was implemented in the controller system to achieve better estimation. Then, the model was used to investigate and analyse voltage swell problem in distribution system. The simulation results show that voltage swell could contaminate distribution network with unwanted harmonic frequencies. Negative sequence frequencies give harmful effects to the network. System connected with proposed STATCOM model illustrates that it could mitigate this problems efficiently.

  17. Analysis of NSTX TF Joint Voltage Measurements

    International Nuclear Information System (INIS)

    Woolley R

    2005-01-01

    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''

  18. Chemoresistive gas sensor

    Science.gov (United States)

    Hirschfeld, T.B.

    1987-06-23

    A chemoresistive gas sensor is provided which has improved sensitivity. A layer of organic semiconductor is disposed between two electrodes which, in turn, are connected to a voltage source. High conductivity material is dispersed within the layer of organic semiconductor in the form of very small particles, or islands. The average interisland spacing is selected so that the predominant mode of current flow is by way of electron funneling. Adsorption of gaseous contaminant onto the layer of organic semiconductor modulates the tunneling current in a quantitative manner. 2 figs.

  19. Development of large high-voltage pressure insulators for the Princeton TFTR [Tokamak Fusion Test Reactor] flexible transmission lines

    International Nuclear Information System (INIS)

    Scalise, D.T.; Fong, E.; Haughian, J.; Prechter, R.

    1986-10-01

    Specially formulated insulator materials with improved strength and high-voltage properties were developed and used for critical components of the flexible transmission lines to the TFTR neutral beam ion sources. These critical components are plates which support central conductors as they exit the high-voltage power supply and enter the ion source enclosure. Each plate acts both as a high-voltage insulator and as a pressure barrier to the SF 6 insulating gas. The original plate was made of commercial glass-epoxy laminate which limited the plate voltage capacity. The newly developed insulator is made of specially-formulated cycloalphatic Di-epoxide whose isotropic properties exhibit increased arc resistance. It is cast in one piece with skirts which greatly increase the breakdown voltage. This paper discusses the design, fabrication and testing of the new insulator

  20. CO2 gas sensitivity of sputtered zinc oxide thin films

    Indian Academy of Sciences (India)

    TECS

    Gas sensitivity; ZnO; sputtering; XRD patterns; structure; thin films. 1. Introduction. Because zinc ... voltage and absorption properties of those fabricated films have been ... tations are useful in many physical applications. The in- plane (Hegde ...

  1. Design and Control of a Dynamic Voltage Restorer

    DEFF Research Database (Denmark)

    Nielsen, John Godsk

    voltage until the energy storage is completely drained or the voltages have returned to normal voltage levels. The control of the HV-DVR is a combined feedforward and feedback control to have a fast response time and load independent voltages. The control is implemented in a rotating dq-reference frame...... electric consumers against voltage dips and surges in the medium and low voltage distribution grid. The thesis first gives an introduction to relevant power quality issues for a DVR and power electronic controllers for voltage dip mitigation. Thereafter the operation and the elements in a DVR are described...... of symmetrical and non-symmetrical voltage dips. In most cases the DVR is capable of restoring the load voltages within 2 ms. During the transition phases load voltage oscillations can be generated and during the return of the supply voltages short time over-voltages can be generated by the DVR. Both...

  2. Decentralized Voltage Control Coordination of On-Load Tap Changer Transformers, Distributed Generation Units and Flexible Loads

    DEFF Research Database (Denmark)

    Romani Dalmau, Aina; Martinez Perez, David; Diaz de Cerio Mendaza, Iker

    2015-01-01

    The increase of distributed generation is expected to generate instabilities, such as power imbalances or voltage deviations in the power system. At the distribution level, maintaining the bus voltages within the stipulated limits is one of the major challenges for the distribution system operator....... Under low penetration levels, several voltage regulation elements have been efficiently employed up to now. However, under large distributed generation levels, the traditional techniques have to be coordinated with new upcoming solutions, such us demand response. In this paper a simple and decentralized...... of the on-load tap changer and the reactive power from dispersed generation while maximizing the capacity usage of the Power-to-Gas load....

  3. Fiber-optic voltage measuring system

    Science.gov (United States)

    Ye, Miaoyuan; Nie, De-Xin; Li, Yan; Peng, Yu; Lin, Qi-Qing; Wang, Jing-Gang

    1993-09-01

    A new fibre optic voltage measuring system has been developed based on the electrooptic effect of bismuth germanium oxide (Bi4Ge3O12)crystal. It uses the LED as the light source. The light beam emitted from the light source is transmitted to the sensor through the optic fibre and the intensity of the output beam is changed by the applied voltage. This optic signal is transmitted to the PIN detector and converted to an electric signal which is processed by the electronic circuit and 8098 single chip microcomputer the output voltage signal obtained is directly proportional to the applied voltage. This paper describes the principle the configuration and the performance parameters of the system. Test results are evaluated and discussed.

  4. Constant potential high-voltage generator

    International Nuclear Information System (INIS)

    Resnick, T.A.; Dupuis, W.A.; Palermo, T.

    1980-01-01

    An X-ray tube voltage generator with automatic stabilization circuitry is disclosed. The generator includes a source of pulsating direct current voltage such as from a rectified 3 phase transformer. This pulsating voltage is supplied to the cathode and anode of an X-ray tube and forms an accelerating potential for electrons within that tube. The accelerating potential is stabilized with a feedback signal which is provided by a feedback network. The network includes an error signal generator which compares an instantaneous accelerating potential with a preferred reference accelerating potential and generates an error function. This error function is transmitted to a control tube grid which in turn causes the voltage difference between X-ray tube cathode and anode to stabilize and thereby reduce the error function. In this way stabilized accelerating potentials are realized and uniform X-ray energy distributions produced. (Auth.)

  5. Nested high voltage generator/particle accelerator

    International Nuclear Information System (INIS)

    Adler, R.J.

    1992-01-01

    This patent describes a modular high voltage particle accelerator having an emission axis and an emission end, the accelerator. It comprises: a plurality of high voltage generators in nested adjacency to form a nested stack, each the generator comprising a cup-like housing having a base and a tubular sleeve extending from the base, a primary transformer winding encircling the nested stack; a secondary transformer winding between each adjacent pair of housings, magnetically linked to the primary transformer winding through the gaps; a power supply respective to each of the secondary windings converting alternating voltage from its respective secondary winding to d.c. voltage, the housings at the emission end forming a hollow throat for particle acceleration, a vacuum seal at the emission end of the throat which enables the throat to be evacuated; a particle source in the thrond power means to energize the primary transformer winding

  6. Poisson simulation for high voltage terminal of test stand for 1MV electrostatic accelerator

    International Nuclear Information System (INIS)

    Park, Sae-Hoon; Kim, Jeong-Tae; Kwon, Hyeok-Jung; Cho, Yong-Sub; Kim, Yu-Seok

    2014-01-01

    KOMAC provide ion beam to user which energy range need to expand to MeV range and develop 1 MV electrostatic accelerator. The specifications of the electrostatic accelerator are 1MV acceleration voltage, 10 mA peak current and variable gas ion. We are developing test stand before set up 1 MV electrostatic accelerator. The test stand voltage is 300 kV and operating time is 8 hours. The test stand is consist of 300 kV high voltage terminal, DC-AC-DC inverter, power supply device inside terminal, 200MHz RF power, 5 kV extraction power supply, 300 kV accelerating tube and vacuum system.. The beam measurement system and beam dump will be installed next to accelerating tube. Poisson code simulation results of the high voltage terminal are presented in this paper. Poisson code has been used to calculate the electric field for high voltage terminal. The results of simulation were verified with reasonable results. The poisson code structure could be apply to the high voltage terminal of the test stand

  7. Poisson simulation for high voltage terminal of test stand for 1MV electrostatic accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sae-Hoon; Kim, Jeong-Tae; Kwon, Hyeok-Jung; Cho, Yong-Sub [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Yu-Seok [Dongguk Univ.., Gyeongju (Korea, Republic of)

    2014-10-15

    KOMAC provide ion beam to user which energy range need to expand to MeV range and develop 1 MV electrostatic accelerator. The specifications of the electrostatic accelerator are 1MV acceleration voltage, 10 mA peak current and variable gas ion. We are developing test stand before set up 1 MV electrostatic accelerator. The test stand voltage is 300 kV and operating time is 8 hours. The test stand is consist of 300 kV high voltage terminal, DC-AC-DC inverter, power supply device inside terminal, 200MHz RF power, 5 kV extraction power supply, 300 kV accelerating tube and vacuum system.. The beam measurement system and beam dump will be installed next to accelerating tube. Poisson code simulation results of the high voltage terminal are presented in this paper. Poisson code has been used to calculate the electric field for high voltage terminal. The results of simulation were verified with reasonable results. The poisson code structure could be apply to the high voltage terminal of the test stand.

  8. Additional ion bombardment in PVD processes generated by a superimposed pulse bias voltage

    International Nuclear Information System (INIS)

    Olbrich, W.; Kampschulte, G.

    1993-01-01

    The superimposed pulse bias voltage is a tool to apply an additional ion bombardment during deposition in physical vapour deposition (PVD) processes. It is generated by the combination of a d.c. ground voltage and a higher d.c. pulse voltage. Using a superimposed pulse bias voltage in ion-assisted PVD processes effects an additional all-around ion bombardment on the surface with ions of higher energy. Both metal and reactive or inert-gas ions are accelerated to the surface. The basic principles and important characteristics of this newly developed process such as ion fluxes or deposition rates are shown. Because of pulsing the high voltage, the deposition temperature does not increase much. The adhesion, structure, morphology and internal stresses are influenced by these additional ion impacts. The columnar growth of the deposited films could be suppressed by using the superimposed pulse bias voltage without increasing the deposition temperature. Different metallizations (Cr and Cu) produced by arc and sputter ion plating are investigated. Carbon-fibre-reinforced epoxy are coated with PVD copper films for further treatment in electrochemical processes. (orig.)

  9. Analysis of the current-voltage characteristics lineshapes of resonant tunneling diodes

    International Nuclear Information System (INIS)

    Rivera, P.H.; Schulz, P.A.

    1996-01-01

    It is discussed the influence of a two dimensional electron gas at the emitter-barrier interface on the current-voltage characteristics of a Ga As-Al Ga As double-barrier quantum well resonant tunneling diode. This effect is characterized by the modification of the space charge distribution along the structure. Within the framework of a self-consistent calculation we analyse the current-voltage characteristics of the tunneling diodes. This analysis permits us to infer different tunneling ways, related to the formation of confined states in the emitter region, and their signatures in the current-voltage characteristics. We show that varying the spacer layer, together with barrier heights, changes drastically the current density-voltage characteristics lineshapes. We compare our results with a variety of current-voltage characteristics lineshapes. We compare our results with a variety of current-voltage characteristics reported in the literature. The general trend of experimental lineshapes can be reproduced and interpreted with our model. The possibility of tunneling paths is predicted for a range that has not yet been explored experimentally. (author). 12 refs., 4 figs

  10. Voltage, Temperature, Frequency Margin Test Report

    DEFF Research Database (Denmark)

    Denver, Troelz

    1999-01-01

    The purpose of the tests is to establish the camera functionality when it is exposed to an extreme environment for prolonged periods, thus simulating the end of life performance. This environment covers temperature, input clock frequency and supply voltage variation......The purpose of the tests is to establish the camera functionality when it is exposed to an extreme environment for prolonged periods, thus simulating the end of life performance. This environment covers temperature, input clock frequency and supply voltage variation...

  11. Detecting Faults In High-Voltage Transformers

    Science.gov (United States)

    Blow, Raymond K.

    1988-01-01

    Simple fixture quickly shows whether high-voltage transformer has excessive voids in dielectric materials and whether high-voltage lead wires too close to transformer case. Fixture is "go/no-go" indicator; corona appears if transformer contains such faults. Nests in wire mesh supported by cap of clear epoxy. If transformer has defects, blue glow of corona appears in mesh and is seen through cap.

  12. Ultra-low Voltage CMOS Cascode Amplifier

    OpenAIRE

    Lehmann, Torsten; Cassia, Marco

    2000-01-01

    In this paper, we design a folded cascode operational transconductance amplifier in a standard CMOS process, which has a measured 69 dB DC gain, a 2 MHz bandwidth and compatible input- and output voltage levels at a 1 V power supply. This is done by a novel Current Driven Bulk (CDB) technique, which reduces the MOST threshold voltage by forcing a constant current though the transistor bulk terminal. We also look at limitations and improvements of this CDB technique.

  13. Ultra-low Voltage CMOS Cascode Amplifier

    DEFF Research Database (Denmark)

    Lehmann, Torsten; Cassia, Marco

    2000-01-01

    In this paper, we design a folded cascode operational transconductance amplifier in a standard CMOS process, which has a measured 69 dB DC gain, a 2 MHz bandwidth and compatible input- and output voltage levels at a 1 V power supply. This is done by a novel Current Driven Bulk (CDB) technique......, which reduces the MOST threshold voltage by forcing a constant current though the transistor bulk terminal. We also look at limitations and improvements of this CDB technique....

  14. Electrical and optical characteristics of dielectric-barrier discharge driven by high voltage nanosecond generator

    International Nuclear Information System (INIS)

    Ahmadeev, V.V.; Kost'yuchenko, S.V.; Kudryavtsev, N.N.; Kurkin, G.A.; Vasilyak, L.M.

    1998-01-01

    Electrical and optical characteristics of the dielectric-barrier discharge in the pressure range of 10-400 Torr were investigated experimentally, particular attention being paid to the discharge homogeneity and to the energy dissipation in the discharge volume. The discharge was driven by a high-voltage pulse generator producing nanosecond high-voltage pulses with an amplitude of 20-30 kV. Air, nitrogen, and helium were used as working gases. The discharge was found to be homogeneous within a wide range of gas pressure. A power density of up to 250 mW/cm 3 has been achieved. (J.U.)

  15. Variation of the Plasma Density in a Glow Discharge Upon the Application of A High Voltage

    International Nuclear Information System (INIS)

    Akman, S.

    2004-01-01

    It is emphasized and demonstrated that, during the formation of an ion-matrix sheath in a glow discharge upon the application of a high voltage pulse, the existing neutral plasma density should change as well. An explicit and practical expression for the neutral plasma density in terms of the gas pressure, secondary electron emission coefficient and the applied voltage is derived, so that the consequent sheath behavior can be formulated correctly. The theoretical result is compared with the data of an experiment, particularly designed and performed to test its validity, and found to be in good agreement with the latter

  16. Modular high voltage power supply for chemical analysis

    Science.gov (United States)

    Stamps, James F [Livermore, CA; Yee, Daniel D [Dublin, CA

    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.

  17. Wind Power Plant Voltage Stability Evaluation: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    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.

  18. Experimental validation of prototype high voltage bushing

    Science.gov (United States)

    Shah, Sejal; Tyagi, H.; Sharma, D.; Parmar, D.; M. N., Vishnudev; Joshi, K.; Patel, K.; Yadav, A.; Patel, R.; Bandyopadhyay, M.; Rotti, C.; Chakraborty, A.

    2017-08-01

    Prototype High voltage bushing (PHVB) is a scaled down configuration of DNB High Voltage Bushing (HVB) of ITER. It is designed for operation at 50 kV DC to ensure operational performance and thereby confirming the design configuration of DNB HVB. Two concentric insulators viz. Ceramic and Fiber reinforced polymer (FRP) rings are used as double layered vacuum boundary for 50 kV isolation between grounded and high voltage flanges. Stress shields are designed for smooth electric field distribution. During ceramic to Kovar brazing, spilling cannot be controlled which may lead to high localized electrostatic stress. To understand spilling phenomenon and precise stress calculation, quantitative analysis was performed using Scanning Electron Microscopy (SEM) of brazed sample and similar configuration modeled while performing the Finite Element (FE) analysis. FE analysis of PHVB is performed to find out electrical stresses on different areas of PHVB and are maintained similar to DNB HV Bushing. With this configuration, the experiment is performed considering ITER like vacuum and electrical parameters. Initial HV test is performed by temporary vacuum sealing arrangements using gaskets/O-rings at both ends in order to achieve desired vacuum and keep the system maintainable. During validation test, 50 kV voltage withstand is performed for one hour. Voltage withstand test for 60 kV DC (20% higher rated voltage) have also been performed without any breakdown. Successful operation of PHVB confirms the design of DNB HV Bushing. In this paper, configuration of PHVB with experimental validation data is presented.

  19. VKCDB: Voltage-gated potassium channel database

    Directory of Open Access Journals (Sweden)

    Gallin Warren J

    2004-01-01

    Full Text Available Abstract Background The family of voltage-gated potassium channels comprises a functionally diverse group of membrane proteins. They help maintain and regulate the potassium ion-based component of the membrane potential and are thus central to many critical physiological processes. VKCDB (Voltage-gated potassium [K] Channel DataBase is a database of structural and functional data on these channels. It is designed as a resource for research on the molecular basis of voltage-gated potassium channel function. Description Voltage-gated potassium channel sequences were identified by using BLASTP to search GENBANK and SWISSPROT. Annotations for all voltage-gated potassium channels were selectively parsed and integrated into VKCDB. Electrophysiological and pharmacological data for the channels were collected from published journal articles. Transmembrane domain predictions by TMHMM and PHD are included for each VKCDB entry. Multiple sequence alignments of conserved domains of channels of the four Kv families and the KCNQ family are also included. Currently VKCDB contains 346 channel entries. It can be browsed and searched using a set of functionally relevant categories. Protein sequences can also be searched using a local BLAST engine. Conclusions VKCDB is a resource for comparative studies of voltage-gated potassium channels. The methods used to construct VKCDB are general; they can be used to create specialized databases for other protein families. VKCDB is accessible at http://vkcdb.biology.ualberta.ca.

  20. Beam induced rf cavity transient voltage

    International Nuclear Information System (INIS)

    Kramer, S.L.; Wang, J.M.

    1998-10-01

    The authors calculate the transient voltage induced in a radio frequency cavity by the injection of a relativistic bunched beam into a circular accelerator. A simplified model of the beam induced voltage, using a single tone current signal, is generated and compared with the voltage induced by a more realistic model of a point-like bunched beam. The high Q limit of the bunched beam model is shown to be related simply to the simplified model. Both models are shown to induce voltages at the resonant frequency ω r of the cavity and at an integer multiple of the bunch revolution frequency (i.e. the accelerating frequency for powered cavity operation) hω ο . The presence of two nearby frequencies in the cavity leads to a modulation of the carrier wave exp(hω ο t). A special emphasis is placed in this paper on studying the modulation function. These models prove useful for computing the transient voltage induced in superconducting rf cavities, which was the motivation behind this research. The modulation of the transient cavity voltage discussed in this paper is the physical basis of the recently observed and explained new kinds of longitudinal rigid dipole mode which differs from the conventional Robinson mode

  1. Advanced Control of the Dynamic Voltage Restorer for Mitigating Voltage Sags in Power Systems

    Directory of Open Access Journals (Sweden)

    Dung Vo Tien

    2018-01-01

    Full Text Available The paper presents a vector control with two cascaded loops to improve the properties of Dynamic Voltage Restorer (DVR to minimize Voltage Sags on the grid. Thereby, a vector controlled structure was built on the rotating dq-coordinate system with the combination of voltage control and the current control. The proposed DVR control method is modelled using MATLAB-Simulink. It is tested using balanced/unbalanced voltage sags as well as fluctuant and distorted voltages. As a result, by using this controlling method, the dynamic characteristics of the system have been improved significantly. The system performed with higher accuracy, faster response and lower distortion in the voltage sags compensation. The paper presents real time experimental results to verify the performance of the proposed method in real environments.

  2. Multifunction Voltage-Mode Filter Using Single Voltage Differencing Differential Difference Amplifier

    Directory of Open Access Journals (Sweden)

    Chaichana Amornchai

    2017-01-01

    Full Text Available In this paper, a voltage mode multifunction filter based on single voltage differencing differential difference amplifier (VDDDA is presented. The proposed filter with three input voltages and single output voltage is constructed with single VDDDA, two capacitors and two resistors. Its quality factor can be adjusted without affecting natural frequency. Also, the natural frequency can be electronically tuned via adjusting of bias current. The filter can offer five output responses, high-pas (HP, band-pass (BP, band-reject (BR, low-pass (LP and all-ass (AP functions in the same circuit topology. The output response can be selected by choosing the suitable input voltage without the component matching condition and the requirement of additional double gain voltage amplifier. PSpice simulation results to confirm an operation of the proposed filter correspond to the theory.

  3. Effect of high-voltage pulsed electric field (HPEF pretreatment on biogas production rates of hybrid Pennisetum by anaerobic fermentation

    Directory of Open Access Journals (Sweden)

    Baijuan Wang

    2018-02-01

    Full Text Available In this paper, the raw materials of hybrid Pennisetum were pretreated in different conditions of high voltage pulsed electric field (HPEF to improve its material utilization ratios and biogas production rates of anaerobic fermentation. Then, anaerobic digestion experiments were conducted within 32 days at moderate temperature (35 °C with TS mass fraction (6%, inoculation rate (20% and initial pH (7.0. It is indicated that compared with the control group, 9 groups of hybrid Pennisetum pretreated by HPEF are obviously superior in gas production efficiency of anaerobic fermentation, and higher in cumulative gas production, peak daily gas production and maximum methane concentration; that the most remarkable stimulation occurs in the HPEF condition of 15 kV/120 Hz/60 min, in that situation, the cumulative gas production in the fermentation period of 32 days is up to 9587 mL, 26.95% higher than that of the control group, the peak daily gas production increases and the range of peak period extends. It is demonstrated that the optimal HPEF pretreatment time is 60 min and three HPEF parameters have a better effect on gas production in the order of voltage > time > frequency; and that the effect degree of treatment parameters on peak daily gas production is voltage, frequency and time in turn. It is concluded that HPEF can improve material utilization ratio and gas production rate of hybrid Pennisetum by anaerobic fermentation and shorten the gas production cycle. By virtue of this physical pretreatment method, the resource of Pennisetum is utilized sufficiently and the classes of energy plants are enlarged effectively. Keywords: Hybrid Pennisetum, Anaerobic fermentation, High voltage pulsed electric field (HPEF, Biogas, Material utilization ratio, Gas generation rate, Model, Stimulation

  4. Engineering of a genetically encodable fluorescent voltage sensor exploiting fast Ci-VSP voltage-sensing movements.

    Science.gov (United States)

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

    2008-06-25

    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.

  5. Voltage scheduling for low power/energy

    Science.gov (United States)

    Manzak, Ali

    2001-07-01

    Power considerations have become an increasingly dominant factor in the design of both portable and desk-top systems. An effective way to reduce power consumption is to lower the supply voltage since voltage is quadratically related to power. This dissertation considers the problem of lowering the supply voltage at (i) the system level and at (ii) the behavioral level. At the system level, the voltage of the variable voltage processor is dynamically changed with the work load. Processors with limited sized buffers as well as those with very large buffers are considered. Given the task arrival times, deadline times, execution times, periods and switching activities, task scheduling algorithms that minimize energy or peak power are developed for the processors equipped with very large buffers. A relation between the operating voltages of the tasks for minimum energy/power is determined using the Lagrange multiplier method, and an iterative algorithm that utilizes this relation is developed. Experimental results show that the voltage assignment obtained by the proposed algorithm is very close (0.1% error) to that of the optimal energy assignment and the optimal peak power (1% error) assignment. Next, on-line and off-fine minimum energy task scheduling algorithms are developed for processors with limited sized buffers. These algorithms have polynomial time complexity and present optimal (off-line) and close-to-optimal (on-line) solutions. A procedure to calculate the minimum buffer size given information about the size of the task (maximum, minimum), execution time (best case, worst case) and deadlines is also presented. At the behavioral level, resources operating at multiple voltages are used to minimize power while maintaining the throughput. Such a scheme has the advantage of allowing modules on the critical paths to be assigned to the highest voltage levels (thus meeting the required timing constraints) while allowing modules on non-critical paths to be assigned

  6. Natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Fraser, J W

    1967-08-01

    This report on the natural gas industry of Canada includes: composition and uses of natural gas, production statistics, exploration and development, reserve estimates, natural gas processing, transportation, and marketing. For the Canadian natural gas industry, 1966 was a year of moderate expansion in all phases, with a strong demand continuing for sulfur and liquid hydrocarbons produced as by-products of gas processing. Value of natural gas production increased to $199 million and ranked sixth in terms of value of mineral ouput in Canada. Currently, natural gas provides over 70% of Canada's energy requirements. Proved remaining marketable reserves are estimated to be in excess of a 29-yr supply.

  7. Gas Sensor

    KAUST Repository

    Luebke, Ryan

    2015-01-22

    A gas sensor using a metal organic framework material can be fully integrated with related circuitry on a single substrate. In an on-chip application, the gas sensor can result in an area-efficient fully integrated gas sensor solution. In one aspect, a gas sensor can include a first gas sensing region including a first pair of electrodes, and a first gas sensitive material proximate to the first pair of electrodes, wherein the first gas sensitive material includes a first metal organic framework material.

  8. Gas Sensor

    KAUST Repository

    Luebke, Ryan; Eddaoudi, Mohamed; Omran, Hesham; Belmabkhout, Youssef; Shekhah, Osama; Salama, Khaled N.

    2015-01-01

    A gas sensor using a metal organic framework material can be fully integrated with related circuitry on a single substrate. In an on-chip application, the gas sensor can result in an area-efficient fully integrated gas sensor solution. In one aspect, a gas sensor can include a first gas sensing region including a first pair of electrodes, and a first gas sensitive material proximate to the first pair of electrodes, wherein the first gas sensitive material includes a first metal organic framework material.

  9. Catalytic recombination of dissociation products with Pt/SnO2 for rare and common isotope long-life, closed-cycle CO2 lasers

    Science.gov (United States)

    Brown, Kenneth G.; Sidney, B. D.; Schryer, D. R.; Upchurch, B. T.; Miller, I. M.

    1986-01-01

    This paper reports results on recombination of pulsed CO2 laser dissociation products with Pt/SnO2 catalysts, and supporting studies in a surrogate laboratory catalyst reactor. The closed-cycle, pulsed CO2 laser has been continuously operated for one million pulses with an overall power degradation of less than 5 percent by flowing the laser gas mixture through a 2-percent Pt/SnO2 catalyst bed. In the surrogate laboratory reactor, experiments have been conducted to determine isotopic exchange with the catalyst when using rare-isotope gases. The effects of catalyst pretreatment, sample weight, composition, and temperature on catalyst efficiency have also been determined.

  10. Gas manufacture

    Energy Technology Data Exchange (ETDEWEB)

    Fell, J W

    1915-05-03

    Retorts for the distillation of shale or coal for the production of oil or illuminating-gas are heated by gas from a generator or a gas-holder, and a portion of the gas from the flue leading to the heating-flues is forced by a steam jet through a by-pass and is injected into the bottom of the retorts. If the gas to be admitted to the retort is cold, it is first heated.

  11. Natural Gas

    OpenAIRE

    Bakar, Wan Azelee Wan Abu; Ali, Rusmidah

    2010-01-01

    Natural gas fuel is a green fuel and becoming very demanding because it is environmental safe and clean. Furthermore, this fuel emits lower levels of potentially harmful by-products into the atmosphere. Most of the explored crude natural gas is of sour gas and yet, very viable and cost effective technology is still need to be developed. Above all, methanation technology is considered a future potential treatment method for converting the sour natural gas to sweet natural gas.

  12. Investigation of Productivity of Brown’s (HHO Gas Generator

    Directory of Open Access Journals (Sweden)

    Andrius Brazdžiūnas

    2017-01-01

    Full Text Available There were made tests of productivity of Brown’s gas generator using different potassium hydroxide (KOH concentration changing voltage and amperage. It is described experimental stand that is used to do researches and methodology of experiments performance. Brown’s gas production in electrolyser (electrolyser – the device that is going electrolysis to use stainless steel (AISI 316 electrodes. It was determined after researches that increasing the potassium hydroxide (KOH concentration in the solution and using the same amperage and voltage of the all concentration results are similar. The highest productivity 1.429 l/min was obtained by using a 120 A amperage and 15 V voltage.

  13. Radioactive gas storage device

    International Nuclear Information System (INIS)

    Seki, Eiji; Kobayashi, Yoshihiro.

    1989-01-01

    The present invention concerns a device of ionizing radioactive gases to be processed in gaseous nuclear fission products in nuclear fuel reprocessing plants, etc., and injecting them into metal substrates for storage. The device comprises a vessel for a tightly closed type outer electrode in which gases to be processed are introduced, an electrode disposed to the inside of the vessel and the target material, a high DC voltage power source for applying high voltage to the electrodes, etc. There are disposed a first electric discharging portion for preparting discharge plasma for ion injection of different electrode distance and a second electric discharging portion for causing stable discharge between the vessel and the electrode. The first electric discharging portion for the ion injection provides an electrode distance suitable to acceleration sputtering and the second electric discharging portion is used for stable discharge. Accordingly, if the gas pressure in the radioactive gas storage device is reduced by the external disturbance, etc., since the second electric discharging portion satisfies the electric discharging conditions, the device can continue electric discharge. (K.M.)

  14. Investigation of phase-wise voltage regulator control logics for compensating voltage deviations in an experimental low voltage network

    DEFF Research Database (Denmark)

    Hu, Junjie; Zecchino, Antonio; Marinelli, Mattia

    2016-01-01

    This paper investigates the control logics of an on-load tap-changer (OLTC) transformer by means of an experimental system validation. The experimental low-voltage unbalanced system consists of a decoupled single-phase OLTC transformer, a 75-metre 16 mm2 cable, a controllable single-phase resistive...... load and an electric vehicle, which has the vehicle-to-grid function. Three control logics of the OLTC transformer are described in the study. The three control logics are classified based on their control objectives and control inputs, which include network currents and voltages, and can be measured...... either locally or remotely. To evaluate and compare the control performances of the three control logics, all the tests use the same loading profiles. The experimental results indicate that the modified line compensation control can regulate voltage in a safe band in the case of various load...

  15. Interconnected High-Voltage Pulsed-Power Converters System Design for H− Ion Sources

    CERN Document Server

    Aguglia, D

    2014-01-01

    This paper presents the design and experimental validations of a system of three new high-voltage (HV) pulsedpower converters for the H− sources. The system requires three pulsed voltages (50, 40, and 25 kV to ground) at 2-Hz repetition rate, for 700 μs of usable flat-top. The solution presents ripplefree output voltages and minimal stored energy to protect the ion source from the consequences of arc events. Experimental results on the final full-scale prototype are presented. In case of short-circuit events, the maximal energy delivered to the source is in the Joule range. HV flat-top stability of 1% is experimentally achieved with a simple Proportional-Integral- Derivative regulation and preliminary tuned H− source (e.g., radio frequency control, gas injection, and so forth). The system is running since more than a year with no power converter failures and damage to the source.

  16. Transmission of power at high voltages

    Energy Technology Data Exchange (ETDEWEB)

    Lane, F J

    1963-01-01

    High voltage transmission is considered to be concerned with circuits and systems operating at or above 132 kV. While the general examination is concerned with ac transmission, dc systems are also included. The choice of voltage for a system will usually involve hazardous assessments of the future requirements of industry, commerce and a changing population. Experience suggests that, if the estimated economic difference between two voltages is not significant, there is good reason to choose the higher voltage, as this will make the better provision for unexpected future expansion. Two principal functions served by transmission circuits in a supply system are: (a) the transportation of energy in bulk from the generator to the reception point in the distribution system; and (b) the interconnection and integration of the generating plant and associated loads. These functions are considered and various types of system are discussed in terms of practicability, viability, quality and continuity of supply. Future developments requiring transmission voltages up to 750 kV will raise many problems which are in the main empirical. Examples are given of the type of problem envisaged and it is suggested that these can only be partially solved by theory and model operation.

  17. Induced Voltage in an Open Wire

    Science.gov (United States)

    Morawetz, K.; Gilbert, M.; Trupp, A.

    2017-07-01

    A puzzle arising from Faraday's law has been considered and solved concerning the question which voltage will be induced in an open wire with a time-varying homogeneous magnetic field. In contrast to closed wires where the voltage is determined by the time variance of the magnetic field and the enclosed area, in an open wire we have to integrate the electric field along the wire. It is found that the longitudinal electric field with respect to the wave vector contributes with 1/3 and the transverse field with 2/3 to the induced voltage. In order to find the electric fields the sources of the magnetic fields are necessary to know. The representation of a spatially homogeneous and time-varying magnetic field implies unavoidably a certain symmetry point or symmetry line which depend on the geometry of the source. As a consequence the induced voltage of an open wire is found to be the area covered with respect to this symmetry line or point perpendicular to the magnetic field. This in turn allows to find the symmetry points of a magnetic field source by measuring the voltage of an open wire placed with different angles in the magnetic field. We present exactly solvable models of the Maxwell equations for a symmetry point and for a symmetry line, respectively. The results are applicable to open circuit problems like corrosion and for astrophysical applications.

  18. Dispersion of breakdown voltage of liquid helium

    International Nuclear Information System (INIS)

    Ishii, Itaru; Noguchi, Takuya

    1978-01-01

    As for the electrical insulation characteristics of liquid helium, the discrepancy among the measured values by each person is very large even in the fundamental DC breakdown voltage in uniform electric field. The dispersion of experimental values obtained in the experiments by the same person is also large. Hereafter, the difference among the mean values obtained by each experimenter will be referred to as ''deviation of mean values'', and the dispersion of measured values around the mean value obtained by the same person as ''deviation around the man value''. The authors have mainly investigated on the latter experimentally. The cryostat was made of stainless steel, and the innermost helium chamber was of 500 mm I.D. and approximately 1200 mm deep. The high voltage electrode was of brass sphere of 25 mm diameter, and the low voltage electrode was of brass plate. The experiment was conducted for liquid helium boiling at 4.2 K and 1 atm, and the breakdown voltage and time lag were measured by applying the approximately square wave impulses of fast rise and long tail, ramp and DC voltages. The cause of the deviation of mean values may be the presence of impurity particles or the effect of electrode shape. As for the deviation around the mean value, the dispersion is large, and its standard deviation may amount to 10 to 20% of the man value. The dispersion is not due to the statistical time lag, but is due to parameters that vary with breakdown. (Wakatsuki, Y.)

  19. Voltage breakdown on niobium and copper surfaces

    International Nuclear Information System (INIS)

    Werner, G.R.; Padamsee, H.; Betzwieser, J.C.; Liu, Y.G.; Rubin, K.H.R.; Shipman, J.E.; Ying, L.T.

    2003-01-01

    Experiments have shown that voltage breakdown in superconducting niobium RF cavities is in many ways similar to voltage breakdown on niobium cathodes in DC voltage gaps; most striking are the distinctive starburst patterns and craters that mark the site of voltage breakdown in both superconducting cavities and DC vacuum gaps. Therefore, we can learn much about RF breakdown from simpler, faster DC experiments. We have direct evidence, in the form of before'' and ''after'' pictures, that breakdown events caused by high surface electric fields occur with high probability at contaminant particles on surfaces. Although the pre-breakdown behavior (field emission) seems to depend mostly on the contaminant particles present and little on the substrate, the breakdown event itself is greatly affected by the substrate-niobium, heavily oxidized niobium, electropolished copper, and diamond-machined copper cathodes lead to different kinds of breakdown events. By studying DC voltage breakdown we hope to learn more details about the processes involved in the transition from field emission to catastrophic arcing and the cratering of the surface; as well as learning how to prevent breakdown, we would like to learn how to cause breakdown, which could be important when ''processing'' cavities to reduce field emission. (author)

  20. Ultraviolet laser-induced voltage in anisotropic shale

    Science.gov (United States)

    Miao, Xinyang; Zhu, Jing; Li, Yizhang; Zhao, Kun; Zhan, Honglei; Yue, Wenzheng

    2018-01-01

    The anisotropy of shales plays a significant role in oil and gas exploration and engineering. Owing to various problems and limitations, anisotropic properties were seldom investigated by direct current resistivity methods. Here in this work, a 248 nm ultraviolet laser was employed to assess the anisotropic electrical response of a dielectric shale. Angular dependence of laser-induced voltages (V p) were obtained, with a data symmetry at the location of 180° and a ~62.2% V p anisotropy of the sample. The double-exponential functions have provided an explanation for the electrical field controlled carrier transportation process in horizontal and vertical directions. The results demonstrate that the combination of optics and electrical logging analysis (Opti-electrical Logging) is a promising technology for the investigation of unconventional reservoirs.

  1. A new gas stripper system for BARC-TIFR Pelletron Accelerator facility: installation and preliminary results

    International Nuclear Information System (INIS)

    Sharma, S.C.; Ninawe, N.G.; Yadav, M.L.; Ekambaram, M.; Ramjilal; Matkar, U.V.; Ansari, Q.N.; Lokare, R.N.; Ramlal; Gupta, A.K.; Bhagwat, P.V.; Pillay, R.G.

    2009-01-01

    The gas-stripper plays a key role in stripping the heavy and molecular ion beams in a tandem accelerator. Efficiency of gas stripper depends on its supporting vacuum pumps. A new recirculating turbo molecular pump-based gas stripper has been installed in the high voltage terminal of Pelletron Accelerator. Re-circulating the stripper gas reduces the flow of gas into the accelerating tubes reducing the transmission losses. Preliminary results obtained using the new gas stripper system are discussed. (author)

  2. Vivitron 1995, transient voltage simulation, high voltage insulator tests, electric field calculation

    International Nuclear Information System (INIS)

    Frick, G.; Osswald, F.; Heusch, B.

    1996-01-01

    Preliminary investigations showed clearly that, because of the discrete electrode structure of the Vivitron, important overvoltage leading to insulator damage can appear in case of a spark. The first high voltage tests showed damage connected with such events. This fact leads to a severe voltage limitation. This work describes, at first, studies made to understand the effects of transients and the associated over-voltage appearing in the Vivitron. Then we present the high voltage tests made with full size Vivitron components using the CN 6 MV machine as a pilot machine. Extensive field calculations were made. These involve simulations of static stresses and transient overvoltages, on insulating boards and electrodes. This work gave us the solutions for arrangements and modifications in the machine. After application, the Vivitron runs now without any sparks and damage at 20 MV. In the same manner, we tested column insulators of a new design and so we will find out how to get to higher voltages. Electric field calculation around the tie bars connecting the discrete electrodes together showed field enhancements when the voltages applied on the discrete electrodes are not equally distributed. This fact is one of the sources of discharges and voltage limitations. A scenario of a spark event is described and indications are given how to proceed towards higher voltages, in the 30 MV range. (orig.)

  3. Low-Voltage Consumption Coordination for Loss Minimization and Voltage Control

    DEFF Research Database (Denmark)

    Juelsgaard, Morten; Sloth, Christoffer; Wisniewski, Rafal

    2014-01-01

    This work presents a strategy for minimizing active power losses in low-voltage grids, by coordinating the consumption of electric vehicles and power generation from solar panels. We show that minimizing losses, also reduces voltage variations, and illustrate how this may be employed for increasing...

  4. Analysis of Voltage Support by Electric Vehicles and Photovoltaic in a Real Danish Low Voltage Network

    DEFF Research Database (Denmark)

    Knezovic, Katarina; Marinelli, Mattia; Juul Møller, René

    2014-01-01

    of incorporating electric vehicles (EVs) in a low voltage distribution network with high penetration of photovoltaic installations (PVs), and focuses on analysing potential voltage support functions from EVs and PVs. In addition, the paper evaluates the benefits that reactive power control may provide...

  5. Subnanosecond breakdown development in high-voltage pulse discharge: Effect of secondary electron emission

    Science.gov (United States)

    Alexandrov, A. L.; Schweigert, I. V.; Zakrevskiy, Dm. E.; Bokhan, P. A.; Gugin, P.; Lavrukhin, M.

    2017-10-01

    A subnanosecond breakdown in high-voltage pulse discharge may be a key tool for superfast commutation of high power devices. The breakdown in high-voltage open discharge at mid-high pressure in helium was studied in experiment and in kinetic simulations. The kinetic model of electron avalanche development was constructed, based on PIC-MCC simulations, including dynamics of electrons, ions and fast helium atoms, produced by ions scattering. Special attention was paid to electron emission processes from cathode, such as: photoemission by Doppler-shifted resonant photons, produced in excitation processes involving fast atoms; electron emission by ions and fast atoms bombardment of cathode; the secondary electron emission (SEE) by hot electrons from bulk plasma. The simulations show that the fast atoms accumulation is the main reason of emission growth at the early stage of breakdown, but at the final stage, when the voltage on plasma gap diminishes, namely the SEE is responsible for subnanosecond rate of current growth. It was shown that the characteristic time of the current growth can be controlled by the SEE yield. The influence of SEE yield for three types of cathode material (titanium, SiC, and CuAlMg-alloy) was tested. By changing the pulse voltage amplitude and gas pressure, the area of existence of subnanosecond breakdown is identified. It is shown that in discharge with SiC and CuAlMg-alloy cathodes (which have enhanced SEE) the current can increase with a subnanosecond characteristic time value as small as τs = 0.4 ns, for the pulse voltage amplitude of 5÷12 kV. An increase of gas pressure from 15 Torr to 30 Torr essentially decreases the time of of current front growth, whereas the pulse voltage variation weakly affects the results.

  6. Light emitting diode driver with differential voltage supply

    NARCIS (Netherlands)

    2015-01-01

    The current invention relates to a driver for driving one or a plurality of LEDs (D1, D2), comprising at least one driving unit (201, 202) adapted to be supplied with a differential voltage, between one first bias voltage (VB1) and one second bias voltage (VB2), the differential voltage being

  7. 30 CFR 75.804 - Underground high-voltage cables.

    Science.gov (United States)

    2010-07-01

    ... 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 resistance... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Underground high-voltage cables. 75.804 Section...

  8. 30 CFR 75.813 - High-voltage longwalls; scope.

    Science.gov (United States)

    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 this...

  9. Voltage Support from Electric Vehicles in Distribution Grid

    DEFF Research Database (Denmark)

    Huang, Shaojun; Pillai, Jayakrishnan Radhakrishna; Bak-Jensen, Birgitte

    2013-01-01

    The paper evaluates the voltage support functions from electric vehicles (EVs) on a typical Danish distribution grid with high EV penetration. In addition to the popular voltage control modes, such as voltage droop charging (low voltage level leads to low charging power) and reactive power support...

  10. 47 CFR 17.54 - Rated lamp voltage.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Rated lamp voltage. 17.54 Section 17.54... voltage. To insure the necessary lumen output by obstruction lights, the rated voltage of incandescent lamps used shall correspond to be within 3 percent higher than the voltage across the lamp socket during...

  11. Low-pressure gas breakdown in longitudinal combined electric fields

    International Nuclear Information System (INIS)

    Lisovskiy, V A; Kharchenko, N D; Yegorenkov, V D

    2010-01-01

    This paper contains the complete experimental and analytical picture of gas breakdown in combined electric fields for arbitrary values of rf and dc fields. To obtain it, we continued the study of the discharge ignition modes in nitrogen with simultaneous application of dc and rf electric fields presented in Lisovskiy et al (2008 J. Phys. D: Appl. Phys. 41 125207). To this end, we studied the effect of rf voltage on dc discharge ignition. When we applied an rf voltage exceeding the one corresponding to the minimum breakdown voltage of a self-sustained rf discharge, the curve of dependence of the dc breakdown voltage of a combined discharge on gas pressure was found to consist of two sections. We got the generalized gas breakdown criterion in the combined field valid for arbitrary values of rf and dc electric fields. The calculation results agree with experimental data satisfactorily.

  12. Determination of the cathode fall voltage in fluorescent lamps by measurement of the operating voltage

    International Nuclear Information System (INIS)

    Hilscher, A.

    2002-01-01

    A new method for the determination of the cathode fall voltage of fluorescent lamps is shown. The cathode fall voltage can be determined by measurement of the lamp operating voltage at constant lamp wall temperature, constant discharge current and variation of the electrode heating current. Commercial lamps, which do not need to be specially prepared, can be used for the measurement. The results show good correlation to other measurements of the cathode fall voltage at various discharge currents by means of capacitive coupling. The measured values of the cathode fall voltage are used for determining the minimum, target and maximum setting of the sum of the squares of the pin currents of one electrode (the so-called SOS value) as a function of the discharge current in fluorescent lamp dimming. (author)

  13. A dynamic voltage restorer (DVR) with selective harmonic compensation at medium voltage level

    DEFF Research Database (Denmark)

    Newman, M.J.; Holmes, D.G.; Nielsen, J.G.

    2005-01-01

    Dynamic voltage restorers (DVRs) are now becoming more established in industry to reduce the impact of voltage sags to sensitive loads. However, DVRs spend most of their time in standby mode, since voltage sags occur very infrequently, and hence their utilization is low. In principle, it would...... be advantageous if the series-connected inverter of a DVR could also be used to compensate for any steady-state load voltage harmonics, since this would increase the power quality "value-added" benefits to the grid system. However, before this can be done, consideration must be given to the control of steady......-state power through the DVR, the increased losses, and the low modulation depths at which the scheme must operate to achieve acceptable harmonic compensation performance. This paper presents a selective harmonic feedback control strategy that can be easily added to medium-voltage DVR systems to provide...

  14. Electrocardiogram voltage discordance: Interpretation of low QRS voltage only in the precordial leads.

    Science.gov (United States)

    Kim, Diana H; Verdino, Ralph J

    To define clinical correlates of low voltage isolated to precordial leads on the surface electrocardiogram (ECG). Low voltage (V) on the ECG is defined as QRS Vvoltage isolated to the precordial leads with normal limb lead voltages is unclear. Twelve-lead ECGs with QRS V>5mm in one or more limb leads and voltage was found in 256 of 150,000 ECGs (~0.2%). 50.4% of patients had discordant ECGs that correlated with classic etiologies, with a higher incidence of LV dilation in those with classic etiologies than those without. Low precordial voltage is associated with classic etiologies and LV dilation. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Voltage stability, bifurcation parameters and continuation methods

    Energy Technology Data Exchange (ETDEWEB)

    Alvarado, F L [Wisconsin Univ., Madison, WI (United States)

    1994-12-31

    This paper considers the importance of the choice of bifurcation parameter in the determination of the voltage stability limit and the maximum power load ability of a system. When the bifurcation parameter is power demand, the two limits are equivalent. However, when other types of load models and bifurcation parameters are considered, the two concepts differ. The continuation method is considered as a method for determination of voltage stability margins. Three variants of the continuation method are described: the continuation parameter is the bifurcation parameter the continuation parameter is initially the bifurcation parameter, but is free to change, and the continuation parameter is a new `arc length` parameter. Implementations of voltage stability software using continuation methods are described. (author) 23 refs., 9 figs.

  16. Critical voltage effects in electron channeling patterns

    International Nuclear Information System (INIS)

    Farrow, R.C.

    1984-01-01

    Electron channeling patterns were used to study critical voltage effects in the metals molybdenum and tungsten. The purpose was to characterize both theoretically and experimentally how a critical voltage will affect the channeling pattern line shapes. The study focused on the second order critical voltage that results from the degeneracy between the Bloch wave states of the (110) and (220) reflections. Theoretical (110) series electron channeling pattern line profiles were calculated using the dynamical theory of Hirsch and Humphreys (1970). A 10 beam dynamical electron diffraction calculation was performed (using complex Fourier lattice potentials) to generate Bloch wave coefficients, excitation amplitudes, and absorption coefficients needed for determining backscattering coefficients and subsequent backscattered electron intensities. The theoretical model is applicable to electron diffraction at all energies since no high energy approximation or perturbation method was used

  17. Intermediate state trapping of a voltage sensor

    DEFF Research Database (Denmark)

    Lacroix, Jérôme J; Pless, Stephan Alexander; Maragliano, Luca

    2012-01-01

    Voltage sensor domains (VSDs) regulate ion channels and enzymes by undergoing conformational changes depending on membrane electrical signals. The molecular mechanisms underlying the VSD transitions are not fully understood. Here, we show that some mutations of I241 in the S1 segment of the Shaker...... Kv channel positively shift the voltage dependence of the VSD movement and alter the functional coupling between VSD and pore domains. Among the I241 mutants, I241W immobilized the VSD movement during activation and deactivation, approximately halfway between the resting and active states......, and drastically shifted the voltage activation of the ionic conductance. This phenotype, which is consistent with a stabilization of an intermediate VSD conformation by the I241W mutation, was diminished by the charge-conserving R2K mutation but not by the charge-neutralizing R2Q mutation. Interestingly, most...

  18. A thermoelectric voltage effect in polyethylene oxide

    CERN Document Server

    Martin, B; Kliem, H

    2003-01-01

    The conductivity of polyethylene oxide (PEO) is described with a three-dimensional hopping model considering electrostatic interactions between the ions. Ions fluctuate over energy-barriers in a multi-well potential. To decide whether positive or negative charges are responsible for this conductivity, the thermoelectric voltage is measured. The samples are embedded between two aluminium-electrodes. The oxide on the interface between the electrodes and the PEO serves as a blocking layer. The temperature of each electrode is controlled by a Peltier element. A temperature step is applied to one electrode by changing the temperature of one of the Peltier elements. Due to this temperature gradient, the mobile charges fluctuate thermally activated from the warmer side to the colder side of the sample. The direction of the measured thermoelectric voltage indicates the type of mobile charges. It is found that positive charges are mobile. Further, it is shown that the absolute value of the thermoelectric voltage depen...

  19. Microwave integrated circuit for Josephson voltage standards

    Science.gov (United States)

    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.

  20. Coplanar strips for Josephson voltage standard circuits

    International Nuclear Information System (INIS)

    Schubert, M.; May, T.; Wende, G.; Fritzsch, L.; Meyer, H.-G.

    2001-01-01

    We present a microwave circuit for Josephson voltage standards. Here, the Josephson junctions are integrated in a microwave transmission line designed as coplanar strips (CPS). The new layout offers the possibility of achieving a higher scale of integration and to considerably simplify the fabrication technology. The characteristic impedance of the CPS is about 50 Ω, and this should be of interest for programmable Josephson voltage standard circuits with SNS or SINIS junctions. To demonstrate the function of the microwave circuit design, conventional 10 V Josephson voltage standard circuits with 17000 Nb/AlO x /Nb junctions were prepared and tested. Stable Shapiro steps at the 10 V level were generated. Furthermore, arrays of 1400 SINIS junctions in this microwave layout exhibited first-order Shapiro steps. Copyright 2001 American Institute of Physics

  1. Voltage control of cavity magnon polariton

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, S., E-mail: kaurs3@myumanitoba.ca; Rao, J. W.; Gui, Y. S.; Hu, C.-M., E-mail: hu@physics.umanitoba.ca [Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); Yao, B. M. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); National Laboratory for Infrared Physics, Chinese Academy of Sciences, Shanghai 200083 (China)

    2016-07-18

    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.

  2. Sensorless Control of IPMSM by Voltage Injection

    DEFF Research Database (Denmark)

    Matzen, Torben N.; Bech, Michael Møller

    2006-01-01

    In this paper a sensorless discrete current control of an Interior Permanent Magnet Synchrouns Motor (IPMSM) by voltage injection is designed and tested. The whole controller is operating in the dq-frame and for this reason the rotor position is essential to know, to transform between the station......In this paper a sensorless discrete current control of an Interior Permanent Magnet Synchrouns Motor (IPMSM) by voltage injection is designed and tested. The whole controller is operating in the dq-frame and for this reason the rotor position is essential to know, to transform between...... the stationary frame and the rotor xed dq-frame. To obtain the position even at standstill a sensorless scheme using voltage injection is added to the current controller....

  3. Semisupervised Community Detection by Voltage Drops

    Directory of Open Access Journals (Sweden)

    Min Ji

    2016-01-01

    Full Text Available Many applications show that semisupervised community detection is one of the important topics and has attracted considerable attention in the study of complex network. In this paper, based on notion of voltage drops and discrete potential theory, a simple and fast semisupervised community detection algorithm is proposed. The label propagation through discrete potential transmission is accomplished by using voltage drops. The complexity of the proposal is OV+E for the sparse network with V vertices and E edges. The obtained voltage value of a vertex can be reflected clearly in the relationship between the vertex and community. The experimental results on four real networks and three benchmarks indicate that the proposed algorithm is effective and flexible. Furthermore, this algorithm is easily applied to graph-based machine learning methods.

  4. Voltage Unbalance Compensation with Smart Three-phase Loads

    DEFF Research Database (Denmark)

    Douglass, Philip; Trintis, Ionut; Munk-Nielsen, Stig

    2016-01-01

    unbalance originating in the power supply network. Two variants of the algorithm are tested: first, using phase-neutral voltage as input, second, using phase-phase voltage. The control algorithm is described, and evaluated in simulations and laboratory tests. Two metrics for quantifying voltage unbalance...... are evaluated: one metric based on the maximum deviation of RMS phaseneutral voltage from the average voltage and one metric based on negative sequence voltage. The tests show that controller that uses phase-neutral voltage as input can in most cases eliminate the deviations of phase voltage from the average...... is caused by asymmetrical loads. These results suggest that the optimal algorithm to reduce system unbalance depends on which system parameter is most important: phase-neutral voltage unbalance, phase-phase voltage unbalance, or current unbalance....

  5. Voltage Quench Dynamics of a Kondo System.

    Science.gov (United States)

    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.

  6. Inductive voltage compensation in superconducting magnet systems

    International Nuclear Information System (INIS)

    Yeh, H.T.; Goddard, J.S.; Shen, S.S.

    1979-01-01

    This paper details several techniques of inductive voltage compensation developed for quench detection in superconducting magnet systems with multiple coils and power supplies, with particular application for the Large Coil Test Facility (LCTF). Sources of noise, their magnitudes, and the sensitivity required for normal zone detection to avoid damage to the magnets are discussed. Two passive compensation schemes (second difference and central difference) are introduced and illustrated by parameters of LCTF; these take advantage of coil symmetries and other system characteristics. An active compensation scheme based on current rate input fom pickup coils and utilizing theory on ac loss voltage for calibration was tested, and the experimental setup and test results are discussed

  7. Technical feasibility study of Voltage Optimization Unit

    DEFF Research Database (Denmark)

    Hu, Junjie; Marinelli, Mattia; Coppo, Massimiliano

    This report provides an analysis on the benefits of a transformer with on load tap chang-ers on each phase that can be applied in the distribution system to accommodate more renewable generations such as photovoltaic power. The main purpose of this research is to verify whether power distribution...... are used as load basics for the analysis. In term of PV genera-tion profiles, a realistic PV output power is assumed. Four relevant indicies such as phase neutral voltage, netural potential voltage, unbalanced factor (VUF), and power losses are evaluated in the present study. The simulation tests include...

  8. Voltage-pulse generator for electron gun

    International Nuclear Information System (INIS)

    Korenev, S.A.; Enchevich, I.B.; Mikhov, M.K.

    1987-01-01

    A voltage-pulse generator with combined capacitive and inductive storage devices of an electron gun is described. The current interrupter is a hydrogen thyratron (TGI1-100/8, TGI1-500/16, or TGI1-1000/25) installed in a short magnetic lens. The current interruption time of the thyratrons is 100-300 nsec. When the capacitive storage device is charged to 1 kV, a voltage pulse with an amplitude of 25 kV is obtained at the load

  9. High-voltage test and measuring techniques

    CERN Document Server

    Hauschild, Wolfgang

    2014-01-01

    It is the intent of this book to combine high-voltage (HV) engineering with HV testing technique and HV measuring technique. Based on long-term experience gained by the authors as lecturer and researcher as well as member in international organizations, such as IEC and CIGRE, the book will reflect the state of the art as well as the future trends in testing and diagnostics of HV equipment to ensure a reliable generation, transmission and distribution of electrical energy. The book is intended not only for experts but also for students in electrical engineering and high-voltage engineering.

  10. Aging of electrochemical double layer capacitors with acetonitrile-based electrolyte at elevated voltages

    International Nuclear Information System (INIS)

    Ruch, P.W.; Cericola, D.; Foelske-Schmitz, A.; Koetz, R.; Wokaun, A.

    2010-01-01

    Laboratory-scale electrochemical capacitor cells with bound activated carbon electrodes and acetonitrile-based electrolyte were aged at various elevated constant cell voltages between 2.75 V and 4.0 V. During the constant voltage tests, the cell capacitance as well as the capacitance and resistance of each electrode was determined. Following each aging experiment, the cells were analyzed by means of electrochemical impedance spectroscopy, and the individual electrodes were characterized by gas adsorption and X-ray photoelectron spectroscopy. At cell voltages above 3.0 V, the positive electrode ages much faster than the negative. Both the capacitance loss and resistance increase of the cell could be totally attributed to the positive electrode. At cell voltages above 3.5 V also the negative electrode aged significantly. X-ray photoelectron spectroscopy indicated the presence of degradation products on the electrode surface with a much thicker layer on the positive electrode. Simultaneously, a significant decrease in electrode porosity could be detected by gas adsorption.

  11. Development and application of a window-type environmental cell in high voltage electron microscope

    International Nuclear Information System (INIS)

    Wakasugi, Takenobu; Isobe, Shigehito; Umeda, Ayaka; Wang, Yongming; Hashimoto, Naoyuki; Ohnuki, Somei

    2013-01-01

    Highlights: ► A window-type environmental cell for a high voltage electron microscope (HVEM) is developed. ► In situ HVEM image of Pd under an H2 gas pressure is obtained. ► The effect of the window materials on the resolution and contamination of the HVEM image is tested. -- Abstract: A close type of an environmental cell was developed for a high voltage electron microscope. Using this cell allowed an in situ observation of hydrogenation in Pd particles under H 2 gas of 0.05 MPa at RT. Two types of window films, Tri-Acetyl-Cellulose (TAC) and Silicon Nitride (SiN), were used for testing the contamination on the sample, as well as the strength for pressure. We confirmed the hydrogenation in diffraction patterns and images, and additionally the image resolution of 0.19 nm was obtained by using a SiN film with a thickness of 17 nm

  12. Development of the piezoelectric gas injection valve for JT-60

    International Nuclear Information System (INIS)

    Kawasaki, Kazuo; Hiratuka, Hajime

    1986-01-01

    Piezoelectric gas injection valve (PEV) for JT-60 have been developed which was a piezo-electric element. The raliability of the PEV under the actual condition of high magnetic fields and high temperatures are veryfied, and it became clear that the PEV had enough throughput range and sufficient repetability for long life throughput characteristics. Remarkables of the developed PEV are summarized as follows, (1) The maximum throughput rate, responce time and helium leakage rate satisfy the desiged specifications. (2) Throughput equation for PEV is clarified by comparison with experiment. (3) Reliabilities of PEV under the actual condition during coil power test become clear. (author)

  13. Effects of Xe Gas Content and Total Gas Pressure on the Discharge Characteristics of Colour Plasma Display Panels

    International Nuclear Information System (INIS)

    Hu Wenbo; Han Mengju; Liang Zhihu

    2006-01-01

    The effects of the Xe gas content and total gas pressure on the discharge characteristics of colour plasma display panels including the sustaining voltage margin, white-field chromaticity, discharge time lag (DTL), discharge current peak, and full-width-at-half-maximum (FWHM) of the discharge current pulse, are experimentally studied. The results indicate that as the Xe gas content in the He-Ne-Xe gas mixture or total pressure increases, the sustaining voltage margin increases, the white-field chromaticity improves, and the discharge current peak has a maximum value, while DTL and FWHM have a minimum value. The mean electron energy in the gas mixture discharge is also calculated through a numerical solution of Boltzmann equation. The experimental results are explained from a view of the mean electron energy variations with the Xe gas content and total gas pressure

  14. ENEL high and medium voltage electrical substations for power supply to urban centers

    International Nuclear Information System (INIS)

    Bargigia, A.; Boatto, C.; Di Mario, A.; Fava, N.; Sciarra, S.; Speziali, R.

    1991-12-01

    Modular high and medium voltage gas insulated electrical substations are being used by ENEL (Italian Electricity Board) to meet the specific needs of urban centers with special design and sizing constraints of a historical/architectural nature. This paper illustrates the key design, construction operation and performance characteristics of these standardized units. The descriptions include brief notes on equipment-transformer interconnection, interchangeability and environmental compatibility. Performance test procedures and results of actual reliability and certification tests on some substations are reported

  15. Control and Testing of a Dynamic Voltage Restorer (DVR) at Medium Voltage Level

    DEFF Research Database (Denmark)

    Nielsen, John Godsk; Newman, Michael; Nielsen, Hans Ove

    2004-01-01

    power sensitive loads from voltage sags. This paper reports practical test results obtained on a medium voltage (10 kV) level using a DVR at a Distribution test facility in Kyndby, Denmark. The DVR was designed to protect a 400-kVA load from a 0.5-p.u. maximum voltage sag. The reported DVR verifies......The dynamic voltage restorer (DVR) has become popular as a cost effective solution for the protection of sensitive loads from voltage sags. Implementations of the DVR have been proposed at both a low voltage (LV) level, as well as a medium voltage (MV) level; and give an opportunity to protect high...... the use of a feed-forward and feed-back technique of the controller and it obtains both good transient and steady state responses. The effect of the DVR on the system is experimentally investigated under both faulted and non-faulted system states, for a variety of linear and non-linear loads. Variable...

  16. Exploration of genetically encoded voltage indicators based on a chimeric voltage sensing domain

    Directory of Open Access Journals (Sweden)

    Yukiko eMishina

    2014-09-01

    Full Text Available Deciphering how the brain generates cognitive function from patterns of electrical signals is one of the ultimate challenges in neuroscience. To this end, it would be highly desirable to monitor the activities of very large numbers of neurons while an animal engages in complex behaviours. Optical imaging of electrical activity using genetically encoded voltage indicators (GEVIs has the potential to meet this challenge. Currently prevalent GEVIs are based on the voltage-sensitive fluorescent protein (VSFP prototypical design or on the voltage dependent state transitions of microbial opsins.We recently introduced a new VSFP design in which the voltage-sensing domain (VSD is sandwiched between a FRET pair of fluorescent proteins (termed VSFP-Butterflies and also demonstrated a series of chimeric VSD in which portions of the VSD of Ciona intestinalis voltage-sensitive phosphatase (Ci-VSP are substituted by homologous portions of a voltage-gated potassium channel subunit. These chimeric VSD had faster sensing kinetics than that of the native Ci-VSD. Here, we describe a new set of VSFPs that combine chimeric VSD with the Butterfly structure. We show that these chimeric VSFP-Butterflies can report membrane voltage oscillations of up to 200 Hz in cultured cells and report sensory evoked cortical population responses in living mice. This class of GEVIs may be suitable for imaging of brain rhythms in behaving mammalians.

  17. Exploration of genetically encoded voltage indicators based on a chimeric voltage sensing domain.

    Science.gov (United States)

    Mishina, Yukiko; Mutoh, Hiroki; Song, Chenchen; Knöpfel, Thomas

    2014-01-01

    Deciphering how the brain generates cognitive function from patterns of electrical signals is one of the ultimate challenges in neuroscience. To this end, it would be highly desirable to monitor the activities of very large numbers of neurons while an animal engages in complex behaviors. Optical imaging of electrical activity using genetically encoded voltage indicators (GEVIs) has the potential to meet this challenge. Currently prevalent GEVIs are based on the voltage-sensitive fluorescent protein (VSFP) prototypical design or on the voltage-dependent state transitions of microbial opsins. We recently introduced a new VSFP design in which the voltage-sensing domain (VSD) is sandwiched between a fluorescence resonance energy transfer pair of fluorescent proteins (termed VSFP-Butterflies) and also demonstrated a series of chimeric VSD in which portions of the VSD of Ciona intestinalis voltage-sensitive phosphatase are substituted by homologous portions of a voltage-gated potassium channel subunit. These chimeric VSD had faster sensing kinetics than that of the native Ci-VSD. Here, we describe a new set of VSFPs that combine chimeric VSD with the Butterfly structure. We show that these chimeric VSFP-Butterflies can report membrane voltage oscillations of up to 200 Hz in cultured cells and report sensory evoked cortical population responses in living mice. This class of GEVIs may be suitable for imaging of brain rhythms in behaving mammalians.

  18. Capturing power at higher voltages from arrays of microbial fuel cells without voltage reversal

    KAUST Repository

    Kim, Younggy

    2011-01-01

    Voltages produced by microbial fuel cells (MFCs) cannot be sustainably increased by linking them in series due to voltage reversal, which substantially reduces stack voltages. It was shown here that MFC voltages can be increased with continuous power production using an electronic circuit containing two sets of multiple capacitors that were alternately charged and discharged (every one second). Capacitors were charged in parallel by the MFCs, but linked in series while discharging to the circuit load (resistor). The parallel charging of the capacitors avoided voltage reversal, while discharging the capacitors in series produced up to 2.5 V with four capacitors. There were negligible energy losses in the circuit compared to 20-40% losses typically obtained with MFCs using DC-DC converters to increase voltage. Coulombic efficiencies were 67% when power was generated via four capacitors, compared to only 38% when individual MFCs were operated with a fixed resistance of 250 Ω. The maximum power produced using the capacitors was not adversely affected by variable performance of the MFCs, showing that power generation can be maintained even if individual MFCs perform differently. Longer capacitor charging and discharging cycles of up to 4 min maintained the average power but increased peak power by up to 2.6 times. These results show that capacitors can be used to easily obtain higher voltages from MFCs, allowing for more useful capture of energy from arrays of MFCs. © 2011 The Royal Society of Chemistry.

  19. Mitigating voltage lead errors of an AC Josephson voltage standard by impedance matching

    Science.gov (United States)

    Zhao, Dongsheng; van den Brom, Helko E.; Houtzager, Ernest

    2017-09-01

    A pulse-driven AC Josephson voltage standard (ACJVS) generates calculable AC voltage signals at low temperatures, whereas measurements are performed with a device under test (DUT) at room temperature. The voltage leads cause the output voltage to show deviations that scale with the frequency squared. Error correction mechanisms investigated so far allow the ACJVS to be operational for frequencies up to 100 kHz. In this paper, calculations are presented to deal with these errors in terms of reflected waves. Impedance matching at the source side of the system, which is loaded with a high-impedance DUT, is proposed as an accurate method to mitigate these errors for frequencies up to 1 MHz. Simulations show that the influence of non-ideal component characteristics, such as the tolerance of the matching resistor, the capacitance of the load input impedance, losses in the voltage leads, non-homogeneity in the voltage leads, a non-ideal on-chip connection and inductors between the Josephson junction array and the voltage leads, can be corrected for using the proposed procedures. The results show that an expanded uncertainty of 12 parts in 106 (k  =  2) at 1 MHz and 0.5 part in 106 (k  =  2) at 100 kHz is within reach.

  20. Fixed target flammable gas upgrades

    International Nuclear Information System (INIS)

    Schmitt, R.; Squires, B.; Gasteyer, T.; Richardson, R.

    1996-12-01

    In the past, fixed target flammable gas systems were not supported in an organized fashion. The Research Division, Mechanical Support Department began to support these gas systems for the 1995 run. This technical memo describes the new approach being used to supply chamber gasses to fixed target experiments at Fermilab. It describes the engineering design features, system safety, system documentation and performance results. Gas mixtures provide the medium for electron detection in proportional and drift chambers. Usually a mixture of a noble gas and a polyatomic quenching gas is used. Sometimes a small amount of electronegative gas is added as well. The mixture required is a function of the specific chamber design, including working voltage, gain requirements, high rate capability, aging and others. For the 1995 fixed target run all the experiments requested once through gas systems. We obtained a summary of problems from the 1990 fixed target run and made a summary of the operations logbook entries from the 1991 run. These summaries primarily include problems involving flammable gas alarms, but also include incidents where Operations was involved or informed. Usually contamination issues were dealt with by the experimenters. The summaries are attached. We discussed past operational issues with the experimenters involved. There were numerous incidents of drift chamber failure where contaminated gas was suspect. However analyses of the gas at the time usually did not show any particular problems. This could have been because the analysis did not look for the troublesome component, the contaminant was concentrated in the gas over the liquid and vented before the sample was taken, or that contaminants were drawn into the chambers directly through leaks or sub-atmospheric pressures. After some study we were unable to determine specific causes of past contamination problems, although in argon-ethane systems the problems were due to the ethane only

  1. Voltage control on a train system

    Science.gov (United States)

    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.

  2. Voltage control of DC islanded microgrids

    DEFF Research Database (Denmark)

    Tucci, Michele; Riverso, Stefano; Quintero, Juan Carlos Vasquez

    2015-01-01

    We propose a new decentralized control scheme for DC Islanded microGrids (ImGs) composed by several Distributed Generation Units (DGUs) with a general interconnection topology. Each local controller regulates to a reference value the voltage of the Point of Common Coupling (PCC...

  3. High voltage pulse generator. [Patent application

    Science.gov (United States)

    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.

  4. Dual voltage power supply with 48 volt

    Energy Technology Data Exchange (ETDEWEB)

    Froeschl, Joachim; Proebstle, Hartmut; Sirch, Ottmar [BMW Group, Muenchen (Germany)

    2012-11-01

    Automotive electrics/electronics have just reached a period of tremendous change. High voltage systems for Hybrid, Plug-In Hybrid or Battery Electric Vehicles with high power electric motors, high energy accumulators and electric climate compressors will be introduced in order to achieve the challenging targets for CO{sub 2} emissions and energy efficiency and to anticipate the mobility of the future. Additionally, innovations and the continuous increase of functionality for comfort, safety, driver assistance and infotainment systems require more and more electrical power of the vehicle power supply at all. On the one hand side electrified vehicles will certainly achieve a significant market share, on the other hand side they will increase the pressure to conventional vehicles with combustion engines for fuel consumption and CO{sub 2} emissions. These vehicles will be enabled to keep their competitiveness by new functions and the optimization of their electric systems. A dual voltage power supply with 48 Volt and 12 Volt will be one of the key technologies to realize these requirements. The power capability of the existing 12 Volt power supply has reached its limits. Further potentials can only be admitted by the introduction of 48 Volt. For this reason the car manufacturers Audi, BMW, Daimler, Porsche and Volkswagen started very early on this item and developed a common specification of the new voltage range. Now, it is necessary to identify the probable systems at this voltage range and to start the developments. (orig.)

  5. Microparticles in high-voltage accelerator tubes

    International Nuclear Information System (INIS)

    Griffith, G.L.; Eastham, D.A.

    1979-01-01

    Microparticles with radii greater than 2 μm have been observed in a high voltage vacuum accelerator tube. The charge acquired by most of the particles is similar to the contact charging of a conducting sphere on a plane. (author)

  6. An Inexpensive Source of High Voltage

    Science.gov (United States)

    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…

  7. Charged particle transport in gaseous nitrogen at intermediate E/N using the voltage transient method

    International Nuclear Information System (INIS)

    Purdie, P.H.; Fletcher, J.

    1992-01-01

    A pulsed swarm of charged particles crossing an inter-electrode gap under the influence of an applied electric field E will produce a pulsed current in the external circuit which, when integrated over time, will result in a transient voltage pulse, the shape and magnitude of which is characteristic of the number of type of charged particles. This voltage transient technique has been used to investigate a gas discharge in nitrogen gas at values of E/N (the ratio of applied electric field to gas number density), such that ionization is non-negligible. The voltage transients have been subjected to a theoretical analysis, which has previously been reported, which includes not only cathode and anode image terms but also both electron and ion diffusion terms. Electron transport parameters are reported for E/N ≤ 350 Td (1 Td = 10 -17 V cm 2 ). Data are also obtained for the drift velocities and diffusion coefficients of the ions operative within the nitrogen discharge. An estimate is obtained for the collisional decay rate of N 2 + . 21 refs., 7 figs

  8. Experimental investigations of argon spark gap recovery times by developing a high voltage double pulse generator.

    Science.gov (United States)

    Reddy, C S; Patel, A S; Naresh, P; Sharma, Archana; Mittal, K C

    2014-06-01

    The voltage recovery in a spark gap for repetitive switching has been a long research interest. A two-pulse technique is used to determine the voltage recovery times of gas spark gap switch with argon gas. First pulse is applied to the spark gap to over-volt the gap and initiate the breakdown and second pulse is used to determine the recovery voltage of the gap. A pulse transformer based double pulse generator capable of generating 40 kV peak pulses with rise time of 300 ns and 1.5 μs FWHM and with a delay of 10 μs-1 s was developed. A matrix transformer topology is used to get fast rise times by reducing L(l)C(d) product in the circuit. Recovery Experiments have been conducted for 2 mm, 3 mm, and 4 mm gap length with 0-2 bars pressure for argon gas. Electrodes of a sparkgap chamber are of rogowsky profile type, made up of stainless steel material, and thickness of 15 mm are used in the recovery study. The variation in the distance and pressure effects the recovery rate of the spark gap. An intermediate plateu is observed in the spark gap recovery curves. Recovery time decreases with increase in pressure and shorter gaps in length are recovering faster than longer gaps.

  9. RF high voltage performance of RF transmission line components on the DIII-D Fast Wave Current Drive (FWCD) system

    International Nuclear Information System (INIS)

    Ferguson, S.W.; Callis, R.W.; Cary, W.P.; Phelps, D.A.; Ponce, D.; Baity, F.W.; Barber, G.

    1995-01-01

    The performance of the high voltage rf components of the DIII-D Fast Wave Current Drive System (FWCD) have been evaluated under various conditions of insulator configuration, insulator material, insulating gas and gas pressure. The insulator materials that have been investigated are alumina, steatite, pyrex, quartz, and teflon. The results of this evaluation are discussed in this paper. Additionally a rf high potter was developed to aid in the evaluation of rf high voltage components. The high potter consists of a 50 Ω, 1/4 wavelength cavity with a variable position short and a 50 ohm matched tap at one end of the cavity. With this configuration rf voltages were generated in excess of 100 kVp in the frequency range 30 to 60 MHz

  10. RF high voltage performance of RF transmission line components on the DIII-D Fast Wave Current Drive (FWCD) System

    International Nuclear Information System (INIS)

    Ferguson, S.W.; Callis, R.W.; Cary, W.P.; Phelps, D.A.; Ponce, D.; Baity, F.W.; Barber, G.

    1995-12-01

    The performance of the high voltage rf components of the DIII-D Fast Wave Current Drive System (FWCD) have been evaluated under various conditions of insulator configuration, insulator material, insulating gas and gas pressure. The insulator materials that have been investigated are alumina, steatite, pyrex, quartz, and teflon. The results of this evaluation are discussed in this paper. Additionally a rf high potter was developed to aid in the evaluation of rf high voltage components. The high potter consists of a 50 Ω, 1/4 wavelength cavity with a variable position short and a 50 ohm matched tap at one end of the cavity. With this configuration rf voltages were generated in excess of 100 kVp in the frequency range 30 to 60 MHz

  11. Grid Voltage Modulated Control of Grid-Connected Voltage Source Inverters under Unbalanced Grid Conditions

    DEFF Research Database (Denmark)

    Li, Mingshen; Gui, Yonghao; Quintero, Juan Carlos Vasquez

    2017-01-01

    In this paper, an improved grid voltage modulated control (GVM) with power compensation is proposed for grid-connected voltage inverters when the grid voltage is unbalanced. The objective of the proposed control is to remove the power ripple and to improve current quality. Three power compensation...... objectives are selected to eliminate the negative sequence components of currents. The modified GVM method is designed to obtain two separate second-order systems for not only the fast convergence rate of the instantaneous active and reactive powers but also the robust performance. In addition, this method...

  12. Statistical Analysis of Partial Discharge Characteristics in Transformer Oil at the “Point-Plane” Electrode at Alternating Voltage

    Directory of Open Access Journals (Sweden)

    Korobeynikov S.M.

    2017-08-01

    Full Text Available In this paper, we consider the problems related to measuring and analyzing the characteristics of partial discharges which are the main instrument for oil-filled high-voltage electrical equipment diagnosing. The experiments on recording of partial discharges in transformer oil have been carried out in the “point-plane” electrode system at alternating current. The instantaneous voltage and the apparent charge have been measured depending on the root-mean-square voltage and the phase angle of partial discharges. This paper aimes at carrying out a statistical analysis of the obtained experimental results, in particular, the construction of a parametric probabilistic model of the dependence of the partial discharge inception voltage distribution on the value of the root-mean-square voltage. It differs from usual discharges which occur in liquid dielectric materials in case of sharp inhomogeneous electrode system. It has been suggested that discharges of a different type are the discharges in gas bubbles that occur when partial discharges in a liquid emerge. This assumption is confirmed by the fact that the number of such discharges increases with increasing the root-mean-square voltage value. It is the main novelty of this paper. This corresponds to the nature of the occurrence of such discharges. After rejecting the observations corresponding to discharges in gas bubbles, a parametric probabilistic model has been constructed. The model obtained makes it possible to determine the probability of partial discharge occurrence in a liquid at a given value of the instantaneous voltage depending on the root-mean-square voltage.

  13. Voltage harmonic elimination with RLC based interface smoothing filter

    International Nuclear Information System (INIS)

    Chandrasekaran, K; Ramachandaramurthy, V K

    2015-01-01

    A method is proposed for designing a Dynamic Voltage Restorer (DVR) with RLC interface smoothing filter. The RLC filter connected between the IGBT based Voltage Source Inverter (VSI) is attempted to eliminate voltage harmonics in the busbar voltage and switching harmonics from VSI by producing a PWM controlled harmonic voltage. In this method, the DVR or series active filter produces PWM voltage that cancels the existing harmonic voltage due to any harmonic voltage source. The proposed method is valid for any distorted busbar voltage. The operating VSI handles no active power but only harmonic power. The DVR is able to suppress the lower order switching harmonics generated by the IGBT based VSI. Good dynamic and transient results obtained. The Total Harmonic Distortion (THD) is minimized to zero at the sensitive load end. Digital simulations are carried out using PSCAD/EMTDC to validate the performance of RLC filter. Simulated results are presented. (paper)

  14. Output voltage calculations in double barrier magnetic tunnel junctions with asymmetric voltage behavior

    KAUST Repository

    Useinov, Arthur; Mryasov, Oleg; Kosel, Jü rgen

    2011-01-01

    In this paper we study the asymmetric voltage behavior (AVB) of the tunnel magnetoresistance (TMR) for single and double barrier magnetic tunnel junctions (MTJs) in range of a quasi-classical free electron model. Numerical calculations of the TMR

  15. Conservation voltage regulation (CVR) applied to energy savings by voltage-adjusting equipment through AMI

    Science.gov (United States)

    Lan, B.-R.; Chang, C.-A.; Huang, P.-Y.; Kuo, C.-H.; Ye, Z.-J.; Shen, B.-C.; Chen, B.-K.

    2017-11-01

    Conservation voltage reduction (CVR) includes peak demand reduction, energy conservation, carbon emission reduction, and electricity bill reduction. This paper analyzes the energy-reduction of Siwei Feeders with applying CVR, which are situated in Penghu region and equipped with smart meters. Furthermore, the applicable voltage reduction range for the feeders will be explored. This study will also investigate how the CVR effect and energy conservation are improved with the voltage control devices integrated. The results of this study can serve as a reference for the Taiwan Power Company to promote and implement voltage reduction and energy conservation techniques. This study is expected to enhance the energy-reduction performance of the Penghu Low Carbon Island Project.

  16. Evaluation of the Voltage Support Strategies for the Low Voltage Grid Connected PV

    DEFF Research Database (Denmark)

    Demirok, Erhan; Sera, Dezso; Teodorescu, Remus

    2010-01-01

    Admissible range of grid voltage is one of the strictest constraints for the penetration of distributed photovoltaic (PV) generators especially connection to low voltage (LV) public networks. Voltage limits are usually fulfilled either by network reinforcements or limiting of power injections from...... PVs. In order to increase PV penetration level further, new voltage support control functions for individual inverters are required. This paper investigates distributed reactive power regulation and active power curtailment strategies regarding the development of PV connection capacity by evaluation...... of reactive power efforts and requirement of minimum active power curtailment. Furthermore, a small scale experimental setup is built to reflect real grid interaction in the laboratory by achieving critical types of grid (weak and sufficiently stiff)....

  17. Modelling voltage sag mitigation using dynamic voltage restorer and analyzing power quality issue

    Science.gov (United States)

    Ismail, Nor Laili; Hidzir, Hizrin Dayana Mohd; Thanakodi, Suresh; Nazar, Nazatul Shiema Moh; Ibrahim, Pungut; Ali, Che Ku Muhammad Sabri Che Ku

    2018-02-01

    Power quality problem which are arise due to a fault or a pulsed load can have caused an interruption of critical load. The modern power systems are becoming more sensitive to the quality of the power supplied by the utility company. Voltage sags and swells, flicker, interruptions, harmonic distortion and other distortion to the sinusoidal waveform are the examples of the power quality problems. The most affected due to these problems is industrial customers who use a lot of sensitive equipment. There has suffered a huge loss to these problems. Resulting of broken or damage equipment if voltage sag exceeds the sensitive threshold of the equipment. Thus, device such as Static Synchronous Compensator (STATCOM) and Dynamic Voltage Restorer (DVR) has been created to solve this problem among users. DVR is a custom power device that most effective and efficient. This paper intended to report the DVR operations during voltage sag compensation.

  18. High voltage capacitor design and the determination of solid dielectric voltage breakdown

    International Nuclear Information System (INIS)

    Hutapea, S.

    1976-01-01

    The value of the external field intensity serves as an electrical insulating material and is a physical characteristic of the substance. Capacitor discharge in the dielectric medium are experimentally investigated. The high voltage power supply and other instrument needed are briefly discussed. Capacitors with working voltage of 30.000 volt and the plastic being used for dielectrics in the capacitors are also discussed. (author)

  19. Flexible and robust N-doped carbon nanofiber film encapsulating uniformly silica nanoparticles: Free-standing long-life and low-cost electrodes for Li- and Na-Ion batteries

    International Nuclear Information System (INIS)

    Li, Liye; Liu, Pengcheng; Zhu, Kongjun; Wang, Jing; Tai, Guoan; Liu, Jinsong

    2017-01-01

    With the wearable electronics progressing rapidly, the demand for flexible, long-life and low-cost electrodes of Li-ion batteries (LIBs) becomes more and more urgent. Due to the abundant resources and low cost, silica (SiO_2), especially the amorphous one, has attracted a lot of interests on the application of anode materials for LIBs. However, SiO_2 still suffer from the poor cycling performance mainly caused by the huge volume change during cycling like other alloy-type materials. Furthermore, it remains a challenge to fabricate the SiO_2–based flexible electrode. Herein, we propose a facile in situ strategy to fabricate the electrospun robust free-standing SiO_2/carbon nanofibers (denoted as in-SCNFs) film constructed by N-doped carbon nanofibers encapsulating uniformly amorphous SiO_2 nanoparticles. The in situ synthesized finer SiO_2 nanoparticles in the in-SCNFs are uniformly encapsulated in flexible carbon nanofibers, which can effectively buffer the volume change. Furthermore, the robust in-SCNFs film possesses the excellent mechanical flexibility and strength. So, when served as the free-standing anode of LIBs, the in-SCNFs film exhibits superior cycling performance. A discharge specific capacity of 405 mAh/g can be delivered even after a long-term 1000 cycles at a large current density of 500 mA/g, and the retention is up to 115%. It is an exciting finding that the in-SCNFs film is also a long-life anode of Na-ion batteries (NIBs). The 99% of initial capacity can be kept after 250 cycles at 500 mA/g. To our best knowledge, this is the first report on the application of SiO_2/C composite for NIBs. These results suggest that the as-fabricated in-SCNFs film can become one promising free-standing long-life anode for LIBs and NIBs.

  20. Voltage Balancing Method on Expert System for 51-Level MMC in High Voltage Direct Current Transmission

    Directory of Open Access Journals (Sweden)

    Yong Chen

    2016-01-01

    Full Text Available The Modular Multilevel Converters (MMC have been a spotlight for the high voltage and high power transmission systems. In the VSC-HVDC (High Voltage Direct Current based on Voltage Source Converter transmission system, the energy of DC link is stored in the distributed capacitors, and the difference of capacitors in parameters and charge rates causes capacitor voltage balance which affects the safety and stability of HVDC system. A method of MMC based on the expert system for reducing the frequency of the submodules (SMs of the IGBT switching frequency is proposed. Firstly, MMC with 51 levels for HVDC is designed. Secondly, the nearest level control (NLC for 51-level MMC is introduced. Thirdly, a modified capacitor voltage balancing method based on expert system for MMC-based HVDC transmission system is proposed. Finally, a simulation platform for 51-level Modular Multilevel Converter is constructed by using MATLAB/SIMULINK. The results indicate that the strategy proposed reduces the switching frequency on the premise of keeping submodule voltage basically identical, which greatly reduces the power losses for MMC-HVDC system.

  1. Field angle dependence of voltage-induced ferromagnetic resonance under DC bias voltage

    International Nuclear Information System (INIS)

    Shiota, Yoichi; Miwa, Shinji; Tamaru, Shingo; Nozaki, Takayuki; Kubota, Hitoshi; Fukushima, Akio; Suzuki, Yoshishige; Yuasa, Shinji

    2016-01-01

    We studied the rectification function of microwaves in CoFeB/MgO-based magnetic tunnel junctions using voltage-induced ferromagnetic resonance (FMR). Our findings reveal that the shape of the structure of the spectrum depends on the rotation angle of the external magnetic field, providing clear evidence that FMR dynamics are excited by voltage-induced magnetic anisotropy changes. Further, enhancement of the rectified voltage was demonstrated under a DC bias voltage. In our experiments, the highest microwave detection sensitivity obtained was 350 mV/mW, at an RF frequency of 1.0 GHz and field angle of θ_H=80°, ϕ_H=0°. The experimental results correlated with those obtained via simulation, and the calculated results revealed the magnetization dynamics at the resonance state. - Highlights: • Examined voltage-induced ferromagnetic resonance (FMR) under various field angles. • FMR dynamics are excited by voltage-induced magnetic anisotropy changes. • Microwave detection sensitivity depends on input RF and elevation angle. • Microwave detection sensitivity=350 mV/mW at RF=1.0 GHz, θ_H=80°, ϕ_H=0°.

  2. Improved detection of electrical activity with a voltage probe based on a voltage-sensing phosphatase.

    Science.gov (United States)

    Tsutsui, Hidekazu; Jinno, Yuka; Tomita, Akiko; Niino, Yusuke; Yamada, Yoshiyuki; Mikoshiba, Katsuhiko; Miyawaki, Atsushi; Okamura, Yasushi

    2013-09-15

      One of the most awaited techniques in modern physiology is the sensitive detection of spatiotemporal electrical activity in a complex network of excitable cells. The use of genetically encoded voltage probes has been expected to enable such analysis. However, in spite of recent progress, existing probes still suffer from low signal amplitude and/or kinetics too slow to detect fast electrical activity. Here, we have developed an improved voltage probe named Mermaid2, which is based on the voltage-sensor domain of the voltage-sensing phosphatase from Ciona intestinalis and Förster energy transfer between a pair of fluorescent proteins. In mammalian cells, Mermaid2 permits ratiometric readouts of fractional changes of more than 50% over a physiologically relevant voltage range with fast kinetics, and it was used to follow a train of action potentials at frequencies of up to 150 Hz. Mermaid2 was also able to detect single action potentials and subthreshold voltage responses in hippocampal neurons in vitro, in addition to cortical electrical activity evoked by sound stimuli in single trials in living mice.

  3. Mathematical modeling of agricultural fires beneath high voltage transmission lines

    International Nuclear Information System (INIS)

    El-Zohri, Emad H.; Shafey, Hamdy M.; Abdel-Salam, M.; Ahmed, A.

    2011-01-01

    This paper presents a mathematical model for agricultural fires based on a multi-phase formulation. The model includes dehydration and pyrolysis of agricultural fuel and pyrolysis products. The model considers a homogeneous distribution of the agricultural solid fuel particles, interacting with the gas flow via source terms. These terms include: drag forces, production of water vapour and pyrolysis products, radiative and convective heat exchange. A multi-phase radiative transfer equation for absorbing-emitting medium is considered to account for the radiative heat exchange between the gas and solid phases of the fire. The main outputs of the present model are most important to study the influence of agricultural fire occurring beneath high voltage transmission lines. The agricultural fire causes a flashover due to the ambient temperature rise and soot accumulation on the insulator of these transmission lines. Numerical results of the present model are obtained for flat grassland fires to study the effects of wind velocity, solid fuel moisture content and ignition length on some selected fire outputs. These outputs include the temperature, velocity, soot volume fraction fields of the gas phase, together with fire propagation rate and flame geometry. The numerical results are compared to the available experimental work in the literature. -- Research highlights: → The model is sensitive to the initial condition of the ignition length affecting the fire propagation rate and width. → The model predicts the effects of both the wind velocity and the fuel moisture content on fire propagation rate, in agreement with the available experimental work in the literature. → The model shows that both the wind velocity and the fuel moisture content are important factors affecting the fire plume thickness, location, and inclination. → The model is able to visualize the flame geometry through tracing radiative heat rates exceeding a threshold value for flame visibility (60 k

  4. TiN coated aluminum electrodes for DC high voltage electron guns

    International Nuclear Information System (INIS)

    Mamun, Md Abdullah A.; Elmustafa, Abdelmageed A.; Taus, Rhys; Forman, Eric; Poelker, Matthew

    2015-01-01

    Preparing electrodes made of metals like stainless steel, for use inside DC high voltage electron guns, is a labor-intensive and time-consuming process. In this paper, the authors report the exceptional high voltage performance of aluminum electrodes coated with hard titanium nitride (TiN). The aluminum electrodes were comparatively easy to manufacture and required only hours of mechanical polishing using silicon carbide paper, prior to coating with TiN by a commercial vendor. The high voltage performance of three TiN-coated aluminum electrodes, before and after gas conditioning with helium, was compared to that of bare aluminum electrodes, and electrodes manufactured from titanium alloy (Ti-6Al-4V). Following gas conditioning, each TiN-coated aluminum electrode reached −225 kV bias voltage while generating less than 100 pA of field emission (<10 pA) using a 40 mm cathode/anode gap, corresponding to field strength of 13.7 MV/m. Smaller gaps were studied to evaluate electrode performance at higher field strength with the best performing TiN-coated aluminum electrode reaching ∼22.5 MV/m with field emission less than 100 pA. These results were comparable to those obtained from our best-performing electrodes manufactured from stainless steel, titanium alloy and niobium, as reported in references cited below. The TiN coating provided a very smooth surface and with mechanical properties of the coating (hardness and modulus) superior to those of stainless steel, titanium-alloy, and niobium electrodes. These features likely contributed to the improved high voltage performance of the TiN-coated aluminum electrodes

  5. Development of Multi-Functional Voltage Restore System

    Science.gov (United States)

    Suzuki, Satoshi; Ueda, Yoshinobu; Koganezawa, Takehisa; Ogihara, Yoshinori; Mori, Kenjiro; Fukazu, Naoaki

    Recently, with the dawn of the electric deregulation, the installation of distributed generation with power electronics device has grown. This current causes a greater concern of power quality, primarily voltage disturbance for power companies, and their interest in power quality is peaking. Utilities are also interested in keeping their customers satisfied, as well as keeping them on-line and creating more revenue for the utility. As a countermeasure against the above surroundings, a variety type of devices based on power electronics has been developed to protect customers' load from power line voltage disturbance. One of them is the series type voltage restore. The series device is an active device, designed to provide a pure sinusoidal load voltage at all times, correcting voltage disturbance. Series type device compensates for voltage anomalies by inserting the ‘missing’ voltage onto the line through insertion transformer and inverter. This paper shows the setting guideline of target level to compensate voltage disturbance, that is, voltage dip, voltage harmonics, voltage imbalance and voltage flicker, and the design approach of the prototype of series voltage restores to accomplish the required compensation level. The prototype system gives satisfactory compensation performance through evaluation tests, which confirm the validity and effectiveness of the system.

  6. Inert gas thrusters

    Science.gov (United States)

    Kaufman, H. R.; Robinson, R. S.

    1980-01-01

    Some advances in component technology for inert gas thrusters are described. The maximum electron emission of a hollow cathode with Ar was increased 60-70% by the use of an enclosed keeper configuration. Operation with Ar, but without emissive oxide, was also obtained. A 30 cm thruster operated with Ar at moderate discharge voltages give double-ion measurements consistent with a double ion correlation developed previously using 15 cm thruster data. An attempt was made to reduce discharge losses by biasing anodes positive of the discharge plasma. The reason this attempt was unsuccessful is not yet clear. The performance of a single-grid ion-optics configuration was evaluated. The ion impingement on the single grid accelerator was found to approach the value expected from the projected blockage when the sheath thickness next to the accelerator was 2-3 times the aperture diameter.

  7. GAS BEARING

    Science.gov (United States)

    Skarstrom, C.W.

    1960-09-01

    A gas lubricated bearing for a rotating shaft is described. The assembly comprises a stationary collar having an annular member resiliently supported thereon. The collar and annular member are provided with cooperating gas passages arranged for admission of pressurized gas which supports and lubricates a bearing block fixed to the rotatable shaft. The resilient means for the annular member support the latter against movement away from the bearing block when the assembly is in operation.

  8. Requirements for gas quality and gas appliances

    NARCIS (Netherlands)

    Levinsky, Howard; Gersen, Sander; Kiewiet, Bert

    2015-01-01

    Introduction The gas transmission network in the Netherlands transports two different qualities of gas, low-calorific gas known as G-gas or L-gas and, high calorific gas (H-gas). These two gas qualities are transported in separate networks, and are connected by means of five blending and conversion

  9. Voltage current characteristics of type III superconductors

    International Nuclear Information System (INIS)

    Dorofejev, G.L.; Imenitov, A.B.; Klimenko, E.Y.

    1980-01-01

    An adequate description of voltage-current characteristics is important in order to understand the nature of high critical current for the electrodynamic construction of type-III superconductors and for commercial superconductor specification. Homogeneous monofilament and multifilament Nb-Ti, Nb-Zr,Nb 3 Sn wires were investigated in different ranges of magnetic field, temperature and current. The shape of the voltage-current characteristics of multifilament wires, and the parameter's dependence on temperature and magnetic field may be explained qualitatively by the longitudinal heterogeneous nature of the filaments. A method of attaining the complete specification of the wire's electro-physical properties is proposed. It includes the traditional description of a critical surface (i.e. the surface corresponding to a certain conventional effective resistivity in T,B,J-space) and a description of any increasing parameter that depends on B and T. (author)

  10. Voltage current characteristics of type III superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Dorofeiev, G L; Imenitov, A B; Klimenko, E Y [Gosudarstvennyi Komitet po Ispol' zovaniyu Atomnoi Ehnergii SSSR, Moscow. Inst. Atomnoi Ehnergii

    1980-06-01

    An adequate description of voltage-current characteristics is important in order to understand the nature of high critical current for the electrodynamic construction of type-III superconductors and for commercial superconductor specification. Homogeneous monofilament and multifilament Nb-Ti, Nb-Zr,Nb/sub 3/Sn wires were investigated in different ranges of magnetic field, temperature and current. The shape of the voltage-current characteristics of multifilament wires, and the parameter's dependence on temperature and magnetic field may be explained qualitatively by the longitudinal heterogeneous nature of the filaments. A method of attaining the complete specification of the wire's electro-physical properties is proposed. It includes the traditional description of a critical surface (i.e. the surface corresponding to a certain conventional effective resistivity in T,B,J-space) and a description of any increasing parameter that depends on B and T.

  11. High-voltage nanosecond pulse shaper

    International Nuclear Information System (INIS)

    Kapishnikov, N.K.; Muratov, V.M.; Shatanov, A.A.

    1987-01-01

    A high-voltage pulse shaper with an output of up to 250 kV, a base duration of ∼ 10 nsec, and a repetition frequency of 50 pulses/sec is described. The described high-voltage nanosecond pulse shaper is designed for one-orbit extraction of an electron beam from a betatron. A diagram of the pulse shaper, which employs a single-stage generator is shown. The shaping element is a low-inductance capacitor bank of series-parallel KVI-3 (2200 pF at 10 kV) or K15-10 (4700 pF at 31.5 kV) disk ceramic capacitors. Four capacitors are connected in parallel and up to 25 are connected in series

  12. Electronic voltage and current transformers testing device.

    Science.gov (United States)

    Pan, Feng; Chen, Ruimin; Xiao, Yong; Sun, Weiming

    2012-01-01

    A method for testing electronic instrument transformers is described, including electronic voltage and current transformers (EVTs, ECTs) with both analog and digital outputs. A testing device prototype is developed. It is based on digital signal processing of the signals that are measured at the secondary outputs of the tested transformer and the reference transformer when the same excitation signal is fed to their primaries. The test that estimates the performance of the prototype has been carried out at the National Centre for High Voltage Measurement and the prototype is approved for testing transformers with precision class up to 0.2 at the industrial frequency (50 Hz or 60 Hz). The device is suitable for on-site testing due to its high accuracy, simple structure and low-cost hardware.

  13. Electrical system architecture having high voltage bus

    Science.gov (United States)

    Hoff, Brian Douglas [East Peoria, IL; Akasam, Sivaprasad [Peoria, IL

    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. Organic dielectrics in high voltage cables

    Energy Technology Data Exchange (ETDEWEB)

    Vermeer, J

    1962-03-01

    It appears that the limit has been reached in the applicability of oil-impregnated paper as the dielectric for ehv cables, as with rising voltages the prevention of conductor losses becomes increasingly difficult, while the dielectric losses of the insulation, increasing as the square of the voltage, contribute to a greater extent to the temperature rise of the conductor. The power transmitting capacity of ehv cables reaches a maximum at 500 to 600 kV for these reasons. Apart from artificial cooling, a substantial improvement can be obtained only with the use of insulating materials with much lower dielectric losses; these can moreover be applied with a smaller wall thickness, but this means higher field strengths. Synthetic polymer materials meet these requirements but can be used successfully only in the form of lapped film tapes impregnated with suitable liquids. The electrical properties of these heterogeneous dielectrics, in particular, their impulse breakdown strengths are studied in detail.

  15. Energy harvesting in high voltage measuring techniques

    International Nuclear Information System (INIS)

    Żyłka, Pawel; Doliński, Marcin

    2016-01-01

    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. (paper)

  16. Engineering of a genetically encodable fluorescent voltage sensor exploiting fast Ci-VSP voltage-sensing movements.

    Directory of Open Access Journals (Sweden)

    Alicia Lundby

    2008-06-01

    Full Text Available 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.

  17. Gas magnetometer

    Science.gov (United States)

    Walker, Thad Gilbert; Lancor, Brian Robert; Wyllie, Robert

    2016-05-03

    Measurement of a precessional rate of a gas, such as an alkali gas, in a magnetic field is made by promoting a non-uniform precession of the gas in which substantially no net magnetic field affects the gas during a majority of the precession cycle. This allows sensitive gases that would be subject to spin-exchange collision de-phasing to be effectively used for extremely sensitive measurements in the presence of an environmental magnetic field such as the Earth's magnetic field.

  18. Gas separating

    Science.gov (United States)

    Gollan, A.

    1988-03-29

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing. 3 figs.

  19. Autonomous Operation of Low Voltage Microgrids

    Directory of Open Access Journals (Sweden)

    Irena Wasiak

    2014-12-01

    Full Text Available The article describes the possibilities of LV microgrids operation in the island mode. Control strategies of energy sources connected to the grid by means of invertors are discussed, either for a microgrid connected to the supplying network or during the island mode operation. The presented results of research were conducted at the Laboratory of Distributed Generation at Lodz University of Technology. The study was performed for two variants of reference voltage source: the battery storage and microturbine respectively.

  20. Multiagent voltage and reactive power control system

    Directory of Open Access Journals (Sweden)

    I. Arkhipov

    2014-12-01

    Full Text Available This paper is devoted to the research of multiagent voltage and reactive power control system development. The prototype of the system has been developed by R&D Center at FGC UES (Russia. The control system architecture is based on the innovative multiagent system theory application that leads to the achievement of several significant advantages (in comparison to traditional control systems implementation such as control system efficiency enhancement, control system survivability and cyber security.

  1. Voltage-Step Transient on Circular Electrodes

    Czech Academy of Sciences Publication Activity Database

    Wein, Ondřej; Tovčigrečko, Valentin

    2011-01-01

    Roč. 41, č. 9 (2011), s. 1065-1075 ISSN 0021-891X R&D Projects: GA ČR GA104/08/0428; GA ČR GA104/09/0972 Institutional research plan: CEZ:AV0Z40720504 Keywords : ohmic loss * voltage-step transient * cottrell asymptote Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.745, year: 2011

  2. High-voltage polymeric insulated cables

    Energy Technology Data Exchange (ETDEWEB)

    Ross, A

    1987-01-01

    Reviews developments in high-voltage (here defined as 25 kV, 66 kV and 132 kV) polymeric insulated cables in the UK over the period 1979-1986, with particular reference to the experience of the Eastern Electricity Board. Outlines the background to the adoption of XPLE-insulated solid cable, and the design, testing, terminations, jointing and costs of 25 kV, 66 kV and 132 kV cables.

  3. High level and long life radioactive wastes. Todays situation and future evolutions. Framework and process of the Granite collegial mission of dialogue. FAQ about the Granite collegial mission of dialogue

    International Nuclear Information System (INIS)

    2000-03-01

    On December 9, 1998, the French government decided the construction of two underground laboratories for the study of the disposal of radioactive wastes in the deep underground. One site will be located in a granitic massif which remains to be determined. This document presents the framework and the different steps of the 'Granite' mission: the situation of radioactive wastes in France, some data about the conditioning, storage and reprocessing of high activity and long life radioactive wastes, the legal framework of the management of radioactive wastes and the related warranties, the disposal in deep underground and the realization of underground research laboratories, the government decision of December 9, 1998, the 'Granite' collegial mission of dialogue and the different steps of the geological surveys about granites. A second part answers some frequently asked questions about the 'Granite' collegial mission of dialogue: decision procedure, planning of the mission, consultation of the geologic survey, role of the mission, public information etc.. (J.S.)

  4. High voltage distribution scheme for large size GEM detector

    International Nuclear Information System (INIS)

    Saini, J.; Kumar, A.; Dubey, A.K.; Negi, V.S.; Chattopadhyay, S.

    2016-01-01

    Gas Electron Multiplier (GEM) detectors will be used for Muon tracking in the Compressed Baryonic Matter (CBM) experiment at the Facility for Anti-proton Ion Research (FAIR) at Darmstadt, Germany. The sizes of the detector modules in the Muon chambers are of the order of 1 metre x 0.5 metre. For construction of these chambers, three GEM foils are used per chamber. These foils are made by two layered 50μm thin kapton foil. Each GEM foil has millions of holes on it. In such a large scale manufacturing of the foils, even after stringent quality controls, some of the holes may still have defects or defects might develop over the time with operating conditions. These defects may result in short-circuit of the entire GEM foil. A short even in a single hole will make entire foil un-usable. To reduce such occurrences, high voltage (HV) segmentation within the foils has been introduced. These segments are powered either by individual HV supply per segment or through an active HV distribution to manage such a large number of segments across the foil. Individual supplies apart from being costly, are highly complex to implement. Additionally, CBM will have high intensity of particles bombarding on the detector causing the change of resistive chain current feeding the GEM detector with the variation in the intensity. This leads to voltage fluctuations across the foil resulting in the gain variation with the particle intensity. Hence, a low cost active HV distribution is designed to take care of the above discussed issues

  5. Voltage-carrying states in superconducting microstrips

    International Nuclear Information System (INIS)

    Stuivinga, M.E.C.

    1983-01-01

    When the critical current is exceeded in a superconducting microstrip, voltage-carrying states with a resistance significantly below the normal state resistance can occur. Phase-slip centers (PSC) appear at about the critical temperature. These are successive local voltage units which manifest themselves as strip-like increments in voltage in the I-V characteristic. For temperatures off the critical temperature the PSC regime degenerates into a region of normal material, a so-called hot spot. These two phenomena, PSC and hot spots, form the subject of this thesis. To gain a better understanding of the phase-slip center process, an experiment was designed to measure local values of the quasi-particle and pair potential. The results of local potential and gap measurements at a PSC in aluminium are presented and discussed. Special attention is paid to pair-breaking interactions which can shorten the relaxation time. A non-linear differential equation is derived which describes the development of a PSC into a normal hot spot under the influence of Joule heating. It incorporates the temperature rise due to the dissipative processes occurring in the charge imbalance tails. Numerical solutions are presented for a set of parameters, including those for aluminium and tin. Subsequently, they are compared with experiments. (Auth.)

  6. Contribution to high voltage matrix switches reliability

    International Nuclear Information System (INIS)

    Lausenaz, Yvan

    2000-01-01

    Nowadays, power electronic equipment requirements are important, concerning performances, quality and reliability. On the other hand, costs have to be reduced in order to satisfy the market rules. To provide cheap, reliability and performances, many standard components with mass production are developed. But the construction of specific products must be considered following these two different points: in one band you can produce specific components, with delay, over-cost problems and eventuality quality and reliability problems, in the other and you can use standard components in a adapted topologies. The CEA of Pierrelatte has adopted this last technique of power electronic conception for the development of these high voltage pulsed power converters. The technique consists in using standard components and to associate them in series and in parallel. The matrix constitutes high voltage macro-switch where electrical parameters are distributed between the synchronized components. This study deals with the reliability of these structures. It brings up the high reliability aspect of MOSFETs matrix associations. Thanks to several homemade test facilities, we obtained lots of data concerning the components we use. The understanding of defects propagation mechanisms in matrix structures has allowed us to put forwards the necessity of robust drive system, adapted clamping voltage protection, and careful geometrical construction. All these reliability considerations in matrix associations have notably allowed the construction of a new matrix structure regrouping all solutions insuring reliability. Reliable and robust, this product has already reaches the industrial stage. (author) [fr

  7. Discussion - a high voltage DC generator

    International Nuclear Information System (INIS)

    Bhagwat, P.V.; Singh, Jagir; Hattangadi, V.A.

    1993-01-01

    One of the requirements for a high power ion source is a high voltage, high current DC generator. The high voltage, high current generator, DISCATRON, presently under development in our laboratory is a rotating disc type electrostatic generator similar in design to the one reported by A. Isoya et al. (1985). It is compact and rugged electrostatic DC generator based on the principle of induction charging by pellet chains used in the pelletron accelerator. It is, basically, a constant-current device with little stored energy, so that, in case of a breakdown, damage to the equipment connected to the output terminals is minimal. Since the present generator is only a proto-type, meant for a study of the practical difficulties that would be encountered in its manufacture, the output voltage and current specified has been kept quite modest viz., 300 kV at 500 μA, maximum. Some results of the preliminary tests carried out with this generator are described. (author). 4 figs

  8. A thermoelectric voltage effect in polyethylene oxide

    International Nuclear Information System (INIS)

    Martin, Bjoern; Wagner, Achim; Kliem, Herbert

    2003-01-01

    The conductivity of polyethylene oxide (PEO) is described with a three-dimensional hopping model considering electrostatic interactions between the ions. Ions fluctuate over energy-barriers in a multi-well potential. To decide whether positive or negative charges are responsible for this conductivity, the thermoelectric voltage is measured. The samples are embedded between two aluminium-electrodes. The oxide on the interface between the electrodes and the PEO serves as a blocking layer. The temperature of each electrode is controlled by a Peltier element. A temperature step is applied to one electrode by changing the temperature of one of the Peltier elements. Due to this temperature gradient, the mobile charges fluctuate thermally activated from the warmer side to the colder side of the sample. The direction of the measured thermoelectric voltage indicates the type of mobile charges. It is found that positive charges are mobile. Further, it is shown that the absolute value of the thermoelectric voltage depends on the energy-barrier heights in the multi-well potential

  9. Artificial intelligence techniques for voltage control

    Energy Technology Data Exchange (ETDEWEB)

    Ekwue, A.; Cheng, D.T.Y.; Macqueen, J.F.

    1997-12-31

    In electric power systems, the advantages of reactive power dispatching or optimisation include improved utilisation of reactive power sources and hence reduction in reactive power flows and real losses of the system; unloading of the system and equipment as a result of reactive flow reduction; the power factors of generation are improved and system security is enhanced; reduced voltage gradients and somewhat higher voltages which result across the system from improved operation; deferred capital investment is new reactive power sources as a result of improved utilisation of existing equipment; and for the National Grid Company plc (NGC), the main advantage is reduced out-of-merit operation. The problem of reactive power control has been studied and widely reported in the literature. Non-linear programming methods as well as linear programming techniques for constraint dispatch have been described. Static optimisation of reactive power sources by the use of sensitivity analysis was described by Kishore and Hill. Long range optimum var planning has been considered and the optimum amount and location of network reactive compensation so as to maintain the system voltage within the desired limits, while operating under normal and various insecurity states, have also been studied using several methods. The objective of this chapter is therefore to review conventional methods as well as AI techniques for reactive power control. (Author)

  10. Thermal voltage noise in layered superconductors

    International Nuclear Information System (INIS)

    Ashkenazy, V.D.; Jung, G.; Shapiro, B.Y.

    1995-01-01

    Thermal voltage noise in the mixed state of type-II superconductors has been calculated taking into account fluctuation modes of nonrigid vortices. It has been shown that bending of vortices leads to new effects in thermal-voltage-noise spectra at high frequencies. The power spectrum reflecting fluctuations of rigid vortices is suppressed at very low frequencies and saturates into a white spectrum at a characteristic frequency depending on the strip width. At high frequencies tilt modes of flexible vortices start to contribute to the fluctuating voltages and the power spectrum undergoes three subsequent magnitude increases, following ω 1/2 -, ω 2 -, and again ω 1/2 -like behavior before becoming white again. It has been shown that for layered superconductors of a moderate anisotropy the second ω 1/2 -like increase disappears at magnetic fields exceeding a certain threshold field corresponding to the crossover field between two-dimensional and three-dimensional vortex-lattice melting. Field dependencies of characteristic frequencies separating different regimes of spectral behavior have been evaluated and shown to be qualitatively different for low and high magnetic fields

  11. A New Asymmetrical Current-fed Converter with Voltage Lifting

    Directory of Open Access Journals (Sweden)

    DELSHAD, M.

    2011-05-01

    Full Text Available This paper presents a new zero voltage switching current-fed DC-DC converter with high voltage gain. In this converter all switches (main and auxiliary turn on under zero voltage switching and turn off under almost zero voltage switching due to snubber capacitor. Furthermore, the voltage spike across the main switch due to leakage inductance of forward transformer is absorbed. The flyback transformer which is connected to the output in series causes to high voltage gain and less voltage stress on the power devices. Considering high efficiency and voltage gain of this converter, it is suitable for green generated systems such as fuel cells or photovoltaic systems. The presented experimental results verify the integrity of the proposed converter.

  12. Manipulating the voltage dependence of tunneling spin torques

    KAUST Repository

    Manchon, Aurelien

    2012-01-01

    Voltage-driven spin transfer torques in magnetic tunnel junctions provide an outstanding tool to design advanced spin-based devices for memory and reprogrammable logic applications. The non-linear voltage dependence of the torque has a direct impact

  13. Voltage gating of mechanosensitive PIEZO channels.

    Science.gov (United States)

    Moroni, Mirko; Servin-Vences, M Rocio; Fleischer, Raluca; Sánchez-Carranza, Oscar; Lewin, Gary R

    2018-03-15

    Mechanosensitive PIEZO ion channels are evolutionarily conserved proteins whose presence is critical for normal physiology in multicellular organisms. Here we show that, in addition to mechanical stimuli, PIEZO channels are also powerfully modulated by voltage and can even switch to a purely voltage-gated mode. Mutations that cause human diseases, such as xerocytosis, profoundly shift voltage sensitivity of PIEZO1 channels toward the resting membrane potential and strongly promote voltage gating. Voltage modulation may be explained by the presence of an inactivation gate in the pore, the opening of which is promoted by outward permeation. Older invertebrate (fly) and vertebrate (fish) PIEZO proteins are also voltage sensitive, but voltage gating is a much more prominent feature of these older channels. We propose that the voltage sensitivity of PIEZO channels is a deep property co-opted to add a regulatory mechanism for PIEZO activation in widely different cellular contexts.

  14. Complete low power controller for high voltage power systems

    International Nuclear Information System (INIS)

    Sumner, R.; Blanar, G.

    1997-01-01

    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

  15. Voltage-dependent gating of hERG potassium channels

    Directory of Open Access Journals (Sweden)

    Yen May eCheng

    2012-05-01

    Full Text Available 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-a-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 voltage-dependent 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.

  16. Voltage Stabilizer Based on SPWM technique Using Microcontroller

    OpenAIRE

    K. N. Tarchanidis; J. N. Lygouras; P. Botsaris

    2013-01-01

    This paper presents an application of the well known SPWM technique on a voltage stabilizer, using a microcontroller. The stabilizer is AC/DC/AC type. So, the system rectifies the input AC voltage to a suitable DC level and the intelligent control of an embedded microcontroller regulates the pulse width of the output voltage in order to produce through a filter a perfect sinusoidal AC voltage. The control program on the microcontroller has the ability to change the FET transistor ...

  17. Voltage Balancing Control of Diode-Clamped Multilevel Inverter

    Directory of Open Access Journals (Sweden)

    ŞCHIOP Adrian

    2013-10-01

    Full Text Available In this paper is developed a control scheme for mono-phase diode clamped inverter to achieve balancing voltages on inverter capacitors. First, it develops a control scheme without taking into account the need to balance voltage on two capacitors. It examines the effects on the output voltage inverter, and then it realizes two control schemes that will balance the voltages. The simulations of control schemes were performed in OrCAD Pspice.

  18. Fluctuation characteristics of arc voltage and jet flow in a non-transferred dc plasma generated at reduced pressure

    International Nuclear Information System (INIS)

    Pan, W X; Guo, Z Y; Meng, X; Huang, H J; Wu, C K

    2009-01-01

    A torch with a set of inter-electrode inserts between the cathode and the anode/nozzle with a wide nozzle exit was designed to generate plasma jets at chamber pressures of 500-10 000 Pa. The variation of the arc voltage was examined with the change in working parameters such as gas flow rate and chamber pressure. The fluctuation in the arc voltage was recorded with an oscilloscope, and the plasma jet fluctuation near the torch exit was observed with a high-speed video camera and detected with a double-electrostatic probe. Results show that the 300 Hz wave originated from the tri-phase rectified power supply was always detected under all generating conditions. Helmholtz oscillations over 3000 Hz was detected superposed on the 300 Hz wave at gas flow rates higher than 8.8 slm with a peak to valley amplitude lower than 5% of the average voltage value. No appreciable voltage fluctuation caused by the irregular arc root movement is detected, and mechanisms for the arc voltage and jet flow fluctuations are discussed.

  19. Experimental study on the influence of radiation on high-voltage insulation gases

    International Nuclear Information System (INIS)

    Fujiwara, Yukio; Inoue, Takashi; Miyamoto, Kenji; Miyamoto, Naoki; Ohara, Yoshihiro; Okumura, Yoshikazu; Watanabe, Kazuhiro

    1999-12-01

    In a neutral beam injection (NBI) system for next generation tokamaks such as International Thermonuclear Experimental Reactor (ITER), insulation gas around a beam source will be irradiated with neutrons and gamma rays from the reactor. It is necessary to evaluate the influence of the radiation on the insulation gas for the engineering design of the ITER-NBI system. In the present paper, the influence of the 60 Co gamma rays on air, SF 6 , C 2 F 6 , CO 2 , and mixing gas of air and SF 6 was studied. Ionization current and voltage-holding characteristics of the gases were measured for an absorbed dose rate of 0.45 Gy/s using parallel disk electrodes whose diameter is 130 mm. Saturation current proved to increase linearly with a gap length between the electrodes, gas pressure, an absorbed dose rate, and molecular weight of the gases. Voltage-holding capability was degraded by about 10 %; the degree of the degradation did not depend on the absorbed dose rate. Dissociative products of SF 6 by the irradiation were also analyzed with a quadrupole mass spectrometer. News peaks that did not exist before irradiation appeared at the m/e of 48, 64, 67, 83, 86, 102, and 105 after irradiation. The amount of the dissociative products turned out to be saturated at a higher absorbed dose. (author)

  20. Manure gas

    Energy Technology Data Exchange (ETDEWEB)

    Carre, I

    1947-05-01

    A short description of the process is given, with gas yields from various feedstocks, and the composition of the gas. Short descriptions of several batch digester designs are given: Algerian, Salubra, Betur, Baudot-Hardoll and Ofta, and Somagaz. The utilization and the economics of the process are discussed. Two diagrams of Ducellier and Isman designs are included.

  1. A High-Voltage Level Tolerant Transistor Circuit

    NARCIS (Netherlands)

    Annema, Anne J.; Geelen, Godefridus Johannes Gertrudis Maria

    2001-01-01

    A high-voltage level tolerant transistor circuit, comprising a plurality of cascoded transistors, including a first transistor (T1) operatively connected to a high-voltage level node (3) and a second transistor (T2) operatively connected to a low-voltage level node (2). The first transistor (T1)

  2. Selective compensation of voltage harmonics in grid-connected microgrids

    DEFF Research Database (Denmark)

    Savaghebi, Mehdi; Vasquez, Juan Carlos; Jalilian, Alireza

    2013-01-01

    In this paper, a novel approach is proposed for selective compensation of main voltage harmonics in a grid-connected microgrid. The aim of compensation is to provide a high voltage quality at the point of common coupling (PCC). PCC voltage quality is of great importance due to sensitive loads tha...... to an acceptable level....

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

    International Nuclear Information System (INIS)

    Fisch, N.J.; Kritz, A.H.; Hunter Coll., New York, NY

    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

  4. High frequency relay protection channels on super high voltage lines

    Energy Technology Data Exchange (ETDEWEB)

    Mikutskii, G V

    1964-08-01

    General aspects of high voltage transmission line design are discussed. The relationships between line voltage and length and line dimensions and power losses are explained. Electrical interference in the line is classified under three headings: interference under normal operating conditions, interference due to insulation faults, and interference due to variations in operating conditions of the high-voltage network.

  5. Resonance analysis in parallel voltage-controlled Distributed Generation inverters

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Chen, Zhe

    2013-01-01

    Thanks to the fast responses of the inner voltage and current control loops, the dynamic behaviors of parallel voltage-controlled Distributed Generation (DG) inverters not only relies on the stability of load sharing among them, but subjects to the interactions between the voltage control loops...

  6. A robust and fast generic voltage sag detection technique

    DEFF Research Database (Denmark)

    L. Dantas, Joacillo; Lima, Francisco Kleber A.; Branco, Carlos Gustavo C.

    2015-01-01

    In this paper, a fast and robust voltage sag detection algorithm, named VPS2D, is introduced. Using the DSOGI, the algorithm creates a virtual positive sequence voltage and monitories the fundamental voltage component of each phase. After calculating the aggregate value in the o:;3-reference fram...

  7. Optical sensors for the measurement of electric current and voltage

    Energy Technology Data Exchange (ETDEWEB)

    Rutgers, W R; Hulshof, H J.M.; Laurensse, I J; van der Wey, A H

    1987-01-01

    Optical sensors for the measurement of electrical current and voltage were developed for application in electric power systems. The current sensor, based on the Faraday effect in a monomode glass fiber, and the voltage sensor, based on the transverse Pockels effect in a crystal, are demonstrated in wide-band (10 MHz) interference-free measurements of pulsed currents and impulse voltages.

  8. High voltage designing of 300.000 Volt

    International Nuclear Information System (INIS)

    Hutapea, Sumihar.

    1978-01-01

    Some methods of designing a.c and d.c high voltage supplies are discussed. A high voltage supply for the Gama Research Centre accelerator is designed using transistor pulse generators. High voltage transformers being made using radio transistor ferrits as a core are also discussed. (author)

  9. A low-ripple chargepump circuit for high voltage applications

    NARCIS (Netherlands)

    Berkhout, M.; Berkhout, M.; van Steenwijk, G.; van Steenwijk, Gijs; van Tuijl, Adrianus Johannes Maria

    1995-01-01

    The subject of this paper is a fully integrated chargepump circuit with a very low output voltage ripple. At a supply voltage of 30V the chargepump can source 1mA at an output voltage of 40V. Two simple modifications to the classical chargepump circuit give a substantial reduction of the output

  10. Voltage stability analysis using a modified continuation load flow ...

    African Journals Online (AJOL)

    This paper addresses the rising problem of identifying the voltage stability limits of load buses in a power system and how to optimally place capacitor banks for voltage stability improvement. This paper uses the concept of the continuation power flow analysis used in voltage stability analysis. It uses the modified ...

  11. On Secondary Control Approaches for Voltage Regulation in DC Microgrids

    DEFF Research Database (Denmark)

    Peyghami, Saeed; Mokhtari, Hossein; Davari, Pooya

    2017-01-01

    Centralized or decentralized secondary controller is commonly employed to regulate the voltage drop raised by the primary controller. However, in the case of high capacity MGs and long feeders with much voltage drop on the line resistances, the conventional methods may not guarantee the voltage r...

  12. On Secondary Control Approaches for Voltage Regulation in DC Microgrids

    DEFF Research Database (Denmark)

    Peyghami Akhuleh, Saeed; Mokhtari, Hossein; Davari, Pooya

    2017-01-01

    Centralized or decentralized secondary controller is commonly employed to regulate the voltage drop raised by the primary controller. However, in the case of high capacity MGs and long feeders with much voltage drop on the line resistances, the conventional methods may not guarantee the voltage...

  13. Landfill gas

    International Nuclear Information System (INIS)

    Hartnell, Gaynor

    2000-01-01

    Following the UK Government's initiative for stimulating renewable energy through the Non-Fossil Fuel Obligation (NFFO), the UK landfill gas industry has more than trebled in size in just 4 years. As a result, UK companies are now in a strong position to offer their skills and services overseas. Ireland, Greece and Spain also resort heavily to disposal to landfill. Particularly rapid growth of the landfill gas market is expected in the OECD-Pacific and NAFTA areas. The article explains that landfill gas is a methane-rich mixture produced by anaerobic decomposition of organic wastes in landfills: under optimum conditions, up to 500 cubic meters of gas can be obtained from 1 tonne of biodegradable waste. Data on the number and capacity of sites in the UK are given. The Landfill Gas Association runs courses to counteract the skills shortage in the UK, and tailored courses for overseas visitors are planned

  14. Gas storing and processing device

    International Nuclear Information System (INIS)

    Kobayashi, Yoshihiro; Takano, Yosoko.

    1988-01-01

    Purpose: To increase the gas injection processing performance and obtain stable accumulation layers by increasing the thickness of the accumulation layers of amorphous alloy. Constitution: The gas storing processing device comprises a cylindrical vessel constituting an outer cathode for introducing gases to be processed, an inner cathode in which transition metal material and rare earth metal material as a sputtering target disposed in the vessel are combined by way of insulating material, an anode cover disposed to the upper portion of the vessel and an anode bottom disposed at the bottom thereof. It is adapted such that DC high voltage sources are connected respectively to the outer and the inner cathodes and sputtering voltage can be applied, removed and controlled independently to the transition metal and the rare earth metal of the inner cathode. This enables to control the composition ratio of the accumulation layers of amorphous alloy formed to the surface of the outer cathode, thereby enabling operation related with the gas injection ratio. (Sekiya, K.)

  15. Voltage-dependent gating of KCNH potassium channels lacking a covalent link between voltage-sensing and pore domains

    Science.gov (United States)

    Lörinczi, Éva; Gómez-Posada, Juan Camilo; de La Peña, Pilar; Tomczak, Adam P.; Fernández-Trillo, Jorge; Leipscher, Ulrike; Stühmer, Walter; Barros, Francisco; Pardo, Luis A.

    2015-03-01

    Voltage-gated channels open paths for ion permeation upon changes in membrane potential, but how voltage changes are coupled to gating is not entirely understood. Two modules can be recognized in voltage-gated potassium channels, one responsible for voltage sensing (transmembrane segments S1 to S4), the other for permeation (S5 and S6). It is generally assumed that the conversion of a conformational change in the voltage sensor into channel gating occurs through the intracellular S4-S5 linker that provides physical continuity between the two regions. Using the pathophysiologically relevant KCNH family, we show that truncated proteins interrupted at, or lacking the S4-S5 linker produce voltage-gated channels in a heterologous model that recapitulate both the voltage-sensing and permeation properties of the complete protein. These observations indicate that voltage sensing by the S4 segment is transduced to the channel gate in the absence of physical continuity between the modules.

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

    Science.gov (United States)

    Rebolledo, Santiago; Perez, Marta E.

    2013-01-01

    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

  17. Stabilization of Voltage Parameters of Induction Generator Excited by a Voltage Inverter

    Directory of Open Access Journals (Sweden)

    Padalko D.A.

    2017-12-01

    Full Text Available The article reveals the operational aspects of induction generator. Methods for stabilization of induction generator (IG parameters under inverter excitation are investigated. The study was carried out using mathematical description and simulation modeling in MATLAB Simulink. The paper provides analysis of causes of generated voltage amplitude and frequency displacement when the loading condition and the rate vary. Due to the parametric resonance nature of IG self-excitation, the author introduces the expression that allows estimating the capacitor capacitance required to maintain the generation process, depending on the rotor speed of electric machine, load nature and rate. Based on the studies, it was proved that it is possible to stabilize the IG voltage parameters by maintaining the magnetizing circuit inductance Lm at the constant level., and realizing a control law close to U/f = const. The study proves that using the inverter together with the voltage regulator allows ensuring the quality of electricity corresponding to modern standards. The necessity of problem solving of the required quality of the voltage by the harmonic component for the exciter - inverter with PWM is shown. The prospects of the power generation system based on induction machine (IM with a semiconductor frequency converter, which serves as an adjustable supplier of capacitive current for IM for autonomous objects, are substantiated. The use of semiconductor frequency converters makes it possible to provide high stability of the output voltage parameters and good speed of the mechatronic generation system with an asynchronous machine.

  18. Dimerization of the voltage-sensing phosphatase controls its voltage-sensing and catalytic activity.

    Science.gov (United States)

    Rayaprolu, Vamseedhar; Royal, Perrine; Stengel, Karen; Sandoz, Guillaume; Kohout, Susy C

    2018-05-07

    Multimerization is a key characteristic of most voltage-sensing proteins. The main exception was thought to be the Ciona intestinalis voltage-sensing phosphatase (Ci-VSP). In this study, we show that multimerization is also critical for Ci-VSP function. Using coimmunoprecipitation and single-molecule pull-down, we find that Ci-VSP stoichiometry is flexible. It exists as both monomers and dimers, with dimers favored at higher concentrations. We show strong dimerization via the voltage-sensing domain (VSD) and weak dimerization via the phosphatase domain. Using voltage-clamp fluorometry, we also find that VSDs cooperate to lower the voltage dependence of activation, thus favoring the activation of Ci-VSP. Finally, using activity assays, we find that dimerization alters Ci-VSP substrate specificity such that only dimeric Ci-VSP is able to dephosphorylate the 3-phosphate from PI(3,4,5)P 3 or PI(3,4)P 2 Our results indicate that dimerization plays a significant role in Ci-VSP function. © 2018 Rayaprolu et al.

  19. Triple Line-Voltage Cascaded VIENNA Converter Applied as the Medium-Voltage AC Drive

    Directory of Open Access Journals (Sweden)

    Jia Zou

    2018-04-01

    Full Text Available A novel rectifier based on a triple line-voltage cascaded VIENNA converter (LVC-VC was proposed. Compared to the conventional cascaded H-bridge converters, the switch voltage stress is lower, and the numbers of switches and dc capacitors are fewer under similar operating conditions in the proposed new multilevel converter. The modeling and control for the LVC-VC ware presented. Based on the analysis of the operation principle of the new converter, the power factor correction of the proposed converter was realized by employing a traditional one-cycle control strategy. The minimum average value and maximum harmonic components of the dc-link voltages of the three VIENNA rectifier modules ware calculated. Three VIENNA dc-link voltages were unbalanced under the unbalanced load conditions, so the zero sequence current was injected to the three inner currents for balancing three VIENNA dc-link voltages. Simulation and the results of the experiment verified the availability of the new proposed multilevel converter and the effectiveness of the corresponding control strategy applied.

  20. Coordinated single-phase control scheme for voltage unbalance reduction in low voltage network.

    Science.gov (United States)

    Pullaguram, Deepak; Mishra, Sukumar; Senroy, Nilanjan

    2017-08-13

    Low voltage (LV) distribution systems are typically unbalanced in nature due to unbalanced loading and unsymmetrical line configuration. This situation is further aggravated by single-phase power injections. A coordinated control scheme is proposed for single-phase sources, to reduce voltage unbalance. A consensus-based coordination is achieved using a multi-agent system, where each agent estimates the averaged global voltage and current magnitudes of individual phases in the LV network. These estimated values are used to modify the reference power of individual single-phase sources, to ensure system-wide balanced voltages and proper power sharing among sources connected to the same phase. Further, the high X / R ratio of the filter, used in the inverter of the single-phase source, enables control of reactive power, to minimize voltage unbalance locally. The proposed scheme is validated by simulating a LV distribution network with multiple single-phase sources subjected to various perturbations.This article is part of the themed issue 'Energy management: flexibility, risk and optimization'. © 2017 The Author(s).