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Sample records for sf6 gas-filled bushings

  1. Preliminary comparison of MP sparking characteristics for SF6 insulating gas mixtures and pure SF6

    International Nuclear Information System (INIS)

    Lindgren, R.; Wegner, H.E.

    1978-01-01

    Operation of the Brookhaven MP-7 tandem Van de Graaff accelerator with pure SF 6 insulating gas is described. Sparking and terminal voltage were monitored and are compared for operation with a mixture of SF 6 , N 2 , CO 2 and O 2 . The accelerator was found to be more difficult to operate with pure SF 6

  2. Research on technology of online gas chromatograph for SF6 decomposition products

    Science.gov (United States)

    Li, L.; Fan, X. P.; Zhou, Y. Y.; Tang, N.; Zou, Z. L.; Liu, M. Z.; Huang, G. J.

    2017-12-01

    Sulfur hexafluoride (SF6) decomposition products were qualitatively and quantitatively analyzed by several gas chromatographs in the laboratory. Test conditions and methods were selected and optimized to minimize and eliminate the SF6’ influences on detection of other trace components. The effective separation and detection of selected characteristic gases were achieved. And by comparison among different types of gas chromatograph, it was found that GPTR-S101 can effectively separate and detect SF6 decomposition products and has best the best detection limit and sensitivity. On the basis of GPTR-S101, online gas chromatograph for SF6decomposition products (GPTR-S201) was developed. It lays the foundation for further online monitoring and diagnosis of SF6.

  3. SF6-alternative gases for application in gas-insulated switchgear

    Science.gov (United States)

    Li, Xingwen; Zhao, Hu; Murphy, Anthony B.

    2018-04-01

    The environmental problems caused by greenhouse gases have received unprecedented attention. Sulfur hexafluoride (SF6), which is the preferred gas for use in gas-insulated switchgear (circuit breakers, disconnect switches, etc. for high-voltage electrical circuits), has a very high global warming potential, and there is a large international effort to find alternative gases. Recently, this effort has made important progress, with promising alternative gases being identified and tested. An overview, in particular the current state of the art, of the study of SF6-alternative gases is presented in the paper. The review focuses on the application of the SF6-alternative gases in gas-insulated switchgear, with detailed analysis of calculations and measurements of their basic physical properties, dielectric strengths, and arc-quenching capabilities. Finally, a discussion of and perspectives on current research and future research directions are presented.

  4. 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.

  5. THEORETICAL GAS CONCENTRATIONS ACHIEVING 100% FILL OF THE VITREOUS CAVITY IN THE POSTOPERATIVE PERIOD: A Gas Eye Model Study.

    Science.gov (United States)

    Williamson, Tom H; Guillemaut, Jean-Yves; Hall, Sheldon K; Hutter, Joseph C; Goddard, Tony

    2017-12-11

    To determine the concentrations of different gas tamponades in air to achieve 100% fill of the vitreous cavity postoperatively and to examine the influence of eye volume on these concentrations. A mathematical model of the mass transfer dynamics of tamponade and blood gases (O2, N2, and CO2) when injected into the eye was used. Mass transfer surface areas were calculated from published anatomical data. The model has been calibrated from published volumetric decay and composition results for three gases sulphahexafluoride (SF6), hexafluoroethane (C2F6), or perfluoropropane (C3F8). The concentrations of these gases (in air) required to achieve 100% fill of the vitreous cavity postoperatively without an intraocular pressure rise were determined. The concentrations were calculated for three volumes of the vitreous cavity to test whether ocular size influenced the results. A table of gas concentrations was produced. In a simulation of pars plana vitrectomy operations in which an 80% to 85% fill of the vitreous cavity with gas was achieved at surgery, the concentrations of the 3 gases in air to achieve 100% fill postoperatively were 10% to 13% for C3F8, 12% to 15% for C2F6, and 19% to 25% for SF6. These were similar to the so-called "nonexpansive" concentrations used in the clinical setting. The calculations were repeated for three different sizes of eye. Aiming for an 80% fill at surgery and 100% postoperatively, an eye with a 4-mL vitreous cavity required 24% SF6, 15% C2F6, or 13% C3F8; 7.2 mL required 25% SF6, 15% C2F6, or 13% C3F8; and 10 mL required 25% SF6, 16% C2F6, or 13% C3F8. When using 100% gas (e.g., used in pneumatic retinopexy), to achieve 100% fill postoperatively, the minimum vitreous cavity fill at surgery was 43% for SF6, 29% for C2F6, and 25% for C3F8 and was only minimally changed by variation in the size of the eye. A table has been produced, which could be used for surgical innovation in gas usage in the vitreous cavity. It provides concentrations

  6. Dielectric properties for SF6 and SF6 mixtures predicted from basic data

    International Nuclear Information System (INIS)

    Kline, L.E.; Davies, D.K.; Chen, C.L.; Chantry, P.J.

    1979-01-01

    We have calculated α and eta, the ionization and attachment coefficients, and (E/N) *, the limiting breakdown electric-field--to--gas-density ratio, in SF 6 and SF 6 mixtures by numerically solving the Boltzmann equation for the electron energy distribution. The calculations require a knowledge of several electron collision cross sections. Published momentum transfer and ionization cross sections for SF 6 were used. We measured various attachment cross sections for SF 6 using electron-beam techniques with mass spectrometric ion detection. We determined a total cross section for electronic excitation of SF 6 by comparing the predicted values of α, eta, and (E/N) * with our measured values obtained from spatial current growth experiments in SF 6 in uniform fields over an extended range of E/N. With this self-consistent set of SF 6 cross sections, together with published He and N 2 cross sections, it was then possible to predict the dielectric properties of SF 6 -He and SF 6 -N 2 mixtures. Published experimental values of α for the SF 6 -He mixtures lie between the values of α calculated with and without ionization of SF 6 by excited He atoms. Published experimental values of (E/N) * agree with our calculations to within 5% in both the SF 6 -He and the SF 6 -N 2 mixtures

  7. Electrical insulation design and evaluation of 60 kV prototype condenser cone bushing for the superconducting equipment

    International Nuclear Information System (INIS)

    Shin, Woo-Ju; Lee, Jong-Geon; Hwang, Jae-Sang; Seong, Jae-Kyu; Lee, Bang-Wook

    2013-01-01

    Highlights: •The optimum design of condenser cone cryogenic bushing was investigated. •Multi-layer aluminum foils in the bushing insulation body was designed and analyzed. •The optimum electric field distribution was selected by simulation. •The 60 kV FRP condenser cone cryogenic bushing was fabricated and tested. •BIL test corresponding to IEC 60137 was successfully performed for the bushing. -- Abstract: A cryogenic bushing is an essential component to be developed for commercial applications of high voltage (HV) superconducting devices. Due to the steep temperature gradient of the ambient of cryogenic bushing, general gas bushing adopting SF6 gas as an insulating media could not be directly used due to the freezing of SF6 gas. Therefore, condenser type bushing with special material considering cryogenic environment would be better choice for superconducting equipment. Considering these circumstance, we focused on the design of condenser bushing made of fiber reinforced plastic (FRP). In case of the design of the condenser bushing, it is very important to reduce the electric field intensification on the mounted flange part of the cryostat, which is the most vulnerable part of bushings. In this paper, design factors of cryogenic bushing were analyzed, and finally 60 kV condenser bushing was fabricated and tested. In order to achieve optimal electric field configuration, the configuration of condenser cone was determined using 2D electric field simulation results. Based on the experimental and the analytical works, 60 kV FRP condenser bushing was fabricated. Finally, the fabricated condenser bushing has been tested by applying lightning impulse and AC overvoltage test. From the test results, it was possible to get satisfactory results which confirm the design of cryogenic bushing in cryogenic environment

  8. Electrical insulation design and evaluation of 60 kV prototype condenser cone bushing for the superconducting equipment

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Woo-Ju, E-mail: shinwooju@hanyang.ac.kr; Lee, Jong-Geon; Hwang, Jae-Sang; Seong, Jae-Kyu; Lee, Bang-Wook, E-mail: bangwook@hanyang.ac.kr

    2013-11-15

    Highlights: •The optimum design of condenser cone cryogenic bushing was investigated. •Multi-layer aluminum foils in the bushing insulation body was designed and analyzed. •The optimum electric field distribution was selected by simulation. •The 60 kV FRP condenser cone cryogenic bushing was fabricated and tested. •BIL test corresponding to IEC 60137 was successfully performed for the bushing. -- Abstract: A cryogenic bushing is an essential component to be developed for commercial applications of high voltage (HV) superconducting devices. Due to the steep temperature gradient of the ambient of cryogenic bushing, general gas bushing adopting SF6 gas as an insulating media could not be directly used due to the freezing of SF6 gas. Therefore, condenser type bushing with special material considering cryogenic environment would be better choice for superconducting equipment. Considering these circumstance, we focused on the design of condenser bushing made of fiber reinforced plastic (FRP). In case of the design of the condenser bushing, it is very important to reduce the electric field intensification on the mounted flange part of the cryostat, which is the most vulnerable part of bushings. In this paper, design factors of cryogenic bushing were analyzed, and finally 60 kV condenser bushing was fabricated and tested. In order to achieve optimal electric field configuration, the configuration of condenser cone was determined using 2D electric field simulation results. Based on the experimental and the analytical works, 60 kV FRP condenser bushing was fabricated. Finally, the fabricated condenser bushing has been tested by applying lightning impulse and AC overvoltage test. From the test results, it was possible to get satisfactory results which confirm the design of cryogenic bushing in cryogenic environment.

  9. Dielectric properties for SF6 and SF6 mixtures predicted from basic data

    International Nuclear Information System (INIS)

    Kline, L.E.; Davies, D.K.; Chen, C.L.; Chantry, P.J.

    1978-01-01

    α and eta, the ionization and attachment coefficients, and (E/N)*, the limiting breakdown electric field-to-gas density ratio, in SF 6 and SF 6 mixtures were calculated by numerically solving the Boltzmann equation for the electron energy distribution. The calculations require a knowledge of several electron collision cross sections. Published momentum transfer and ionization cross sections for SF 6 were used. Various attachment cross sections for SF 6 were measured by using electron beam techniques with mass spectrometric ion detection. A total cross section for electronic excitation of SF 6 was determined by comparing the predicted values of α, eta, and (E/N)* with measured values obtained from spatial current growth experiments in SF 6 in uniform fields over an extended range of E/N. With this self-consistent set of SF 6 cross sections, together with published He cross sections, it was then possible to predict the dielectric properties of SF 6 --He mixtures. Published experimental values of α for these mixtures lie between the values of α calculated with and without ionization of SF 6 by excited He atoms. Published experimental values of (E/N)* agree with the calculations to within 5%. 11 figures

  10. Modification in existing SF6 gas handling system at 14UD BARC-TIFR Pelletron Accelerator, Mumbai

    International Nuclear Information System (INIS)

    Ninawe, N.G.; Gupta, S.K.; Ramjilal; Sparrow, Hillary; Sharma, S.C.; Bhagwat, P.V.; Salvi, S.B.

    2003-01-01

    BARC-TIFR 14 UD Pelletron Accelerator facility at TIFR, Mumbai is operational since inception 1989. The accelerator is housed inside a pressure vessel of 6 metre diameter, 25 metre long and 525m 3 volume. The accelerator tank is pressurized with SF 6 at 80 to 100 psig in order to achieve 14MV. The inventory of SF 6 gas is about 18,000 Kg (approximately) at 80 psig. SF 6 gas can be transported from Accelerator tank to storage tank using gas handling system, which consists of oil free compressor, vacuum pump, dust filters, oil filters, dryers etc

  11. SF6 and the greenhouse effect

    International Nuclear Information System (INIS)

    Gjaerde, Anne Cathrine; Rein, Asgaut; Hegerberg, Rolf; Kulsetaas, John

    1997-01-01

    The gas SF 6 (sulfur hexafluoride) is much used as an insulation medium in electric switchgear and breakers. However, there has been some recent concern about the possible contribution of SF 6 to the global greenhouse effect. This report presents some collected facts about SF 6 emission. The concentration of SF 6 in the atmosphere is very low and will probably remain so until the end of the next century. Hence the contribution of SF 6 to the greenhouse effect is negligible. Most of the SF 6 emission comes from the magnesium and aluminium industries. In 1993, SF 6 emission from switchgear in the Norwegian distribution grid corresponded to only 0.2 per million of the CO 2 emission in Norway. But the quantity of SF 6 accumulated in electric switchgear is considerable. However, losing it to the atmosphere can be avoided by using recirculation or destruction systems for SF 6 in connection with maintenance and replacement of components. Norwegian climate policy aims at taking measures against SF 6 and other climate gases on a par with CO 2 . Taxation measures have been suggested for SF 6 . Atmospheric SF 6 does not influence the ozone layer. 3 refs., 8 figs

  12. Near-critical density filling of the SF6 fluid cell for the ALI-R-DECLIC experiment in weightlessness

    Science.gov (United States)

    Lecoutre, C.; Marre, S.; Garrabos, Y.; Beysens, D.; Hahn, I.

    2018-05-01

    Analyses of ground-based experiments on near-critical fluids to precisely determine their density can be hampered by several effects, especially the density stratification of the sample, the liquid wetting behavior at the cell walls, and a possible singular curvature of the "rectilinear" diameter of the density coexisting curve. For the latter effect, theoretical efforts have been made to understand the amplitude and shape of the critical hook of the density diameter, which depart from predictions from the so-called ideal lattice-gas model of the uniaxial 3D-Ising universality class. In order to optimize the observation of these subtle effects on the position and shape of the liquid-vapor meniscus in the particular case of SF6, we have designed and filled a cell that is highly symmetrized with respect to any median plane of the total fluid volume. In such a viewed quasi-perfect symmetrical fluid volume, the precise detection of the meniscus position and shape for different orientations of the cell with respect to the Earth's gravity acceleration field becomes a sensitive probe to estimate the cell mean density filling and to test the singular diameter effects. After integration of this cell in the ALI-R insert, we take benefit of the high optical and thermal performances of the DECLIC Engineering Model. Here we present the sensitive imaging method providing the precise ground-based SF6 benchmark data. From these data analysis it is found that the temperature dependence of the meniscus position does not reflect the expected critical hook in the rectilinear density diameter. Therefore the off-density criticality of the cell is accurately estimated, before near future experiments using the same ALI-R insert in the DECLIC facility already on-board the International Space Station.

  13. Theoretical study of OCCHCN as a potential alternative insulation gas for SF6

    Directory of Open Access Journals (Sweden)

    Zhiguo Chen

    2017-01-01

    Full Text Available Cyanoketene (OCCHCN has been reported as a potential alternative insulation gas for SF6 in Patent US0135817. Stationary point equilibrium geometries on the ground state have been optimized at the B3LYP/6-311+G(d,p level, and the harmonic vibration frequencies are calculated at the same level. The HOMO-LUMO energy gaps (Eg, ionization potentials (IP, and electron affinities (EA of the studied molecules are obtained. The minimum energy path (MEP is obtained by the intrinsic reaction coordinate (IRC theory, and the energetic information is further refined by QCISD(T (single-point method. The results show that OCCHCN can be used as SF6 alternative insulation gas in high voltage equipment according to potential energy surface analysis. As the isomerization and the cleavage reactions potential barriers are lower than the Eg and IP values, resulting in OCCHCN is not easy to be ionized and excited.

  14. A Novel Approach to Power Circuit Breaker Design for Replacement of SF6

    Directory of Open Access Journals (Sweden)

    D. J. Telfer

    2004-01-01

    Full Text Available This contribution explores the role of PTFE ablation in enhancing current interruption for various background gases in high voltage circuit breakers. An assessment of the current interruption capability has been made in terms of the arcing duration and the contact gap length at which critical arc extinction is achieved. These observations are supported by measurements of the magnitude of extinction and re-ignition voltage peaks. Most previous and other current experimental work on gas filled circuit breaker design follows conventional wisdom in investigating arcing behaviours at elevated gas pressures (usually up to 6 bar. But in this work we concentrate on the effects of using low gas pressures (less than 1 bar in the presence of a close-fitting shield of ablatant polymer material (PTFE that surrounds the electrode assembly of an experimental high power circuit breaker. We demonstrate that for several different gases, arc extinction capability compares well under these conditions with SF6, suggesting that SF6 could be replaced entirely in this novel system by more environmentally friendly gases. Moreover, the critical contact gap lengths at extinction are only slightly greater than when using SF6 at 6 bar. Weight loss measurements from the ablatant shield suggest that a chemical puffer action is the most likely mechanism for achieving the observed arc extinctions in this system.

  15. Laser Spectroscopy on Ozone Destruction by SF6 Decomposed Products

    OpenAIRE

    北嶋, 巌; 村上, 和幸; 田中, 淳一; 岡井, 善四郎

    2002-01-01

    This paper reports on the identification of the SF6 decomposed products and the possibility of the ozone destruction by it. SF6 gas absorbs very strongly the 10.6μm P branch of C02 laser beam,so that the trace detection under ppb will be easily performed by the laser photo-acoustic method. We observed a new absorption spectra within the 9.6μm P branch resulted from the decomposed molecules after 2 hours 1 Hz-pulsed discharge of SF6 gas. As a resu1t ofthe gas chromatograph, it will be assumed ...

  16. Electrochemical and Infrared Absorption Spectroscopy Detection of SF6 Decomposition Products

    Directory of Open Access Journals (Sweden)

    Ming Dong

    2017-11-01

    Full Text Available Sulfur hexafluoride (SF6 gas-insulated electrical equipment is widely used in high-voltage (HV and extra-high-voltage (EHV power systems. Partial discharge (PD and local heating can occur in the electrical equipment because of insulation faults, which results in SF6 decomposition and ultimately generates several types of decomposition products. These SF6 decomposition products can be qualitatively and quantitatively detected with relevant detection methods, and such detection contributes to diagnosing the internal faults and evaluating the security risks of the equipment. At present, multiple detection methods exist for analyzing the SF6 decomposition products, and electrochemical sensing (ES and infrared (IR spectroscopy are well suited for application in online detection. In this study, the combination of ES with IR spectroscopy is used to detect SF6 gas decomposition. First, the characteristics of these two detection methods are studied, and the data analysis matrix is established. Then, a qualitative and quantitative analysis ES-IR model is established by adopting a two-step approach. A SF6 decomposition detector is designed and manufactured by combining an electrochemical sensor and IR spectroscopy technology. The detector is used to detect SF6 gas decomposition and is verified to reliably and accurately detect the gas components and concentrations.

  17. Electrochemical and Infrared Absorption Spectroscopy Detection of SF6 Decomposition Products

    Science.gov (United States)

    Dong, Ming; Ren, Ming; Ye, Rixin

    2017-01-01

    Sulfur hexafluoride (SF6) gas-insulated electrical equipment is widely used in high-voltage (HV) and extra-high-voltage (EHV) power systems. Partial discharge (PD) and local heating can occur in the electrical equipment because of insulation faults, which results in SF6 decomposition and ultimately generates several types of decomposition products. These SF6 decomposition products can be qualitatively and quantitatively detected with relevant detection methods, and such detection contributes to diagnosing the internal faults and evaluating the security risks of the equipment. At present, multiple detection methods exist for analyzing the SF6 decomposition products, and electrochemical sensing (ES) and infrared (IR) spectroscopy are well suited for application in online detection. In this study, the combination of ES with IR spectroscopy is used to detect SF6 gas decomposition. First, the characteristics of these two detection methods are studied, and the data analysis matrix is established. Then, a qualitative and quantitative analysis ES-IR model is established by adopting a two-step approach. A SF6 decomposition detector is designed and manufactured by combining an electrochemical sensor and IR spectroscopy technology. The detector is used to detect SF6 gas decomposition and is verified to reliably and accurately detect the gas components and concentrations. PMID:29140268

  18. Gas transport below artificial recharge ponds: insights from dissolved noble gases and a dual gas (SF6 and 3He) tracer experiment.

    Science.gov (United States)

    Clark, Jordan F; Hudson, G Bryant; Avisar, Dror

    2005-06-01

    A dual gas tracer experiment using sulfur hexafluoride (SF6) and an isotope of helium (3He) and measurements of dissolved noble gases was performed at the El Rio spreading grounds to examine gas transport and trapped air below an artificial recharge pond with a very high recharge rate (approximately 4 m day(-1)). Noble gas concentrations in the groundwater were greater than in surface water due to excess air formation showing that trapped air exists below the pond. Breakthrough curves of SF6 and 3He at two nearby production wells were very similar and suggest that nonequilibrium gas transfer was occurring between the percolating water and the trapped air. At one well screened between 50 and 90 m below ground, both tracers were detected after 5 days and reached a maximum at approximately 24 days. Despite the potential dilution caused by mixing within the production well, the maximum concentration was approximately 25% of the mean pond concentration. More than 50% of the SF6 recharged was recovered by the production wells during the 18 month long experiment. Our results demonstrate that at artificial recharge sites with high infiltration rates and moderately deep water tables, transport times between recharge locations and wells determined with gas tracer experiments are reliable.

  19. A global model for SF6 plasmas coupling reaction kinetics in the gas phase and on the surface of the reactor walls

    International Nuclear Information System (INIS)

    Kokkoris, George; Panagiotopoulos, Apostolos; Gogolides, Evangelos; Goodyear, Andy; Cooke, Mike

    2009-01-01

    Gas phase and reactor wall-surface kinetics are coupled in a global model for SF 6 plasmas. A complete set of gas phase and surface reactions is formulated. The rate coefficients of the electron impact reactions are based on pertinent cross section data from the literature, which are integrated over a Druyvesteyn electron energy distribution function. The rate coefficients of the surface reactions are adjustable parameters and are calculated by fitting the model to experimental data from an inductively coupled plasma reactor, i.e. F atom density and pressure change after the ignition of the discharge. The model predicts that SF 6 , F, F 2 and SF 4 are the dominant neutral species while SF 5 + and F - are the dominant ions. The fit sheds light on the interaction between the gas phase and the reactor walls. A loss mechanism for SF x radicals by deposition of a fluoro-sulfur film on the reactor walls is needed to predict the experimental data. It is found that there is a net production of SF 5 , F 2 and SF 6 , and a net consumption of F, SF 3 and SF 4 on the reactor walls. Surface reactions as well as reactions between neutral species in the gas phase are found to be important sources and sinks of the neutral species.

  20. Particle contamination in gas-insulated systems: new control methods and optimum SF6/N2 mixtures

    International Nuclear Information System (INIS)

    Pace, M.O.; Adcock, J.L.; Christophorou, L.G.

    1984-01-01

    The feasibilities of two new separate techniques to control particle contamination in practical gas-insulated sytems were tested in a small-scale concentric cylinder geometry. In one technique an insulating coating was first formed on the particles in a contaminated system by low-pressure discharges in appropriate gases such as 1-C 3 F 6 and c-C 4 F 8 . When SF 6 was subsequently introduced into the same system at practical pressure as the operating insulation, the considerable harm ordinarily caused by particles was found to be eliminated. The nature of the coating formed also on the electrodes in this process was studied, with the conclusion that the observed benefits were primarily due to coating on particles, not on electrodes. In the second technique the particles, moved randomly by electrical stress, struck and adhered to the surface of a tacky insulating solid material; they were subsequently encapsulated in a melt-resolidify cycle without electrical stress. This trapping technique was also found to eliminate the harmful effects of particles in SF 6 at practical pressure. A technique for producing a trapping material with temperature characteristics appropriate for practical apparatus was devised. The effect of particle contamination on the dielectric strength of SF 6 /N 2 mixtures was studied as a function of total pressure and percentage of each gas. Optimum total pressure (approx. 6 atm) and optimum percentages (60% SF 6 /40% N 2 ) were observed in breakdown tests in particle-contaminated concentric cylinder geometry

  1. Leak detection of SF6 gas pressure vessel safety devices at BARC-TIFR Pelletron accelerator

    International Nuclear Information System (INIS)

    Ninawe, N.G.; Sharma, S.C.; Nair, J.P.; Sparrow, H.; Bolar, P.C.; Gudekar, P.V.; Mahapatra, S.; Vishwakarma, R.S.; Ramjilal; Matkar, U.V.; Gore, J.A.; Gupta, A.K.

    2015-01-01

    Pelletron accelerator is in operation since last more than 26 years. To achieve desired voltage gradient SF6 gas of about 20 tons is used to have 75-80 psig pressure in main accelerator tank. During accelerator tank maintenance gas is transferred to four storage tanks, kept in open space in the vicinity of sea. Recently refurbishment and retrofitting of four storage tanks was carried out which includes the installation of new drift space, rupture disc assembly, relief valves and manual valves along with civil and painting work. All components to be installed were tested for high pressure. Helium gas sniffer technique was used to check micro leaks for new joints for all components before installing for storage tanks. Subsequently, the tanks were tested up to 90 psig SF6 gradually in succession. No pressure drop was observed in storage tanks. This work was carried out as per recommendation of the then particle accelerator committee (PASC). (author)

  2. Thermoregulated Nitric Cryosystem for Cooling Gas-Filled Detectors of Ionizing Radiation

    Directory of Open Access Journals (Sweden)

    Zharkov I.P.

    2015-09-01

    Full Text Available Cryosystem for cooling and filling of gas-filled detectors of ionizing radiation with compressed inert gas on the basis of wide-nitrogen cryostat, which provides detetector temperature control in a range of 173 — 293 K and its stabilization with accuracy of ± 1°. The work was carried out within the Ukraine — NATO Program of Collaboration, Grant SfP #984655.

  3. Assessment of Eco-friendly Gases for Electrical Insulation to Replace the Most Potent Industrial Greenhouse Gas SF6.

    Science.gov (United States)

    Rabie, Mohamed; Franck, Christian M

    2018-01-16

    Gases for electrical insulation are essential for the operation of electric power equipment. This Review gives a brief history of gaseous insulation that involved the emergence of the most potent industrial greenhouse gas known today, namely sulfur hexafluoride. SF 6 paved the way to space-saving equipment for the transmission and distribution of electrical energy. Its ever-rising usage in the electrical grid also played a decisive role in the continuous increase of atmospheric SF 6 abundance over the last decades. This Review broadly covers the environmental concerns related to SF 6 emissions and assesses the latest generation of eco-friendly replacement gases. They offer great potential for reducing greenhouse gas emissions from electrical equipment but at the same time involve technical trade-offs. The rumors of one or the other being superior seem premature, in particular because of the lack of dielectric, environmental, and chemical information for these relatively novel compounds and their dissociation products during operation.

  4. Refurbishment and retrofitting of SF6 gas storage tanks of the pelletron accelerator

    International Nuclear Information System (INIS)

    Reddy, G.R.; Datar, V.M.; Parulekar, Y.M.

    2015-01-01

    The BARC-TIFR Pelletron Accelerator Facility has completed more than twenty six years of successful round-the-clock operation, serving diverse users from institutions within and outside DAE. The main accelerating structure and associated subsystems are housed in the accelerator tank under SF 6 gas medium. During maintenance of the accelerator, the SF 6 gas present in the accelerator tank is transferred in the four storage tanks located on the terrace of the building open to outside environment. These four storage tanks (with ∼ 1/4th of the main tank volume each) are ∼ 4.27 m in diameter and ∼ 10 m in height each and are supported on RCC ring beams which are monolithically connected with the RCC structure below. Over the years, the anchor bolts and the base plates of support structure of storage tanks were found corroded and the foundation RCC ring beam indicated a few corrosion cracks. Health assessment of relevant structures and components were carried out. Considering the limitations of existing anchorage and also giving due considerations for reparability and replaceability, a new anchorage system was designed. The entire refurbishment and retrofitting works pertaining to the four SF 6 gas storage tanks was executed in a time bound manner to comply with the then PASC (Particle Accelerator Safety Committee) recommendations successfully, without disrupting the operations of the round-the-clock running Pelletron Accelerator facility. In addition, the thickness measurements for the storage tanks were performed. The relief valves and rupture disc assemblies across the storage tanks were replaced and reinstalled after introducing appropriate manual valves as suggested by the PASC. A new test set up was fabricated to perform pneumatic testing at the recommended pressure off-line for these relief valves and rupture disc assemblies prior to reinstallation. This paper describes the comprehensive rehabilitation and retrofitting procedures that were carried out at the

  5. Emissions from SF6 appliances in Norway. Additional report No. 2

    International Nuclear Information System (INIS)

    Gjarede, Anne Cathrine

    1999-01-01

    The report presents facts regarding the Norwegian SF 6 emissions and the significance for the Norwegian climatic gas accounts in order to evaluate whether 12-24 kV SF 6 appliances are environmentally acceptable. Estimations show that emissions from such equipment contribute with about 0.2 % of the total Norwegian CO 2 emissions in 1993. The SF 6 which is stored in electric appliances, may either be recycled or decomposed to more environmentally acceptable end products. The report concludes that the contribution to the greenhouse effects from SF 6 appliances is minimal

  6. Electrochemical and Infrared Absorption Spectroscopy Detection of SF6 Decomposition Products

    OpenAIRE

    Dong, Ming; Zhang, Chongxing; Ren, Ming; Albarracín, Ricardo; Ye, Rixin

    2017-01-01

    Sulfur hexafluoride (SF6) gas-insulated electrical equipment is widely used in high-voltage (HV) and extra-high-voltage (EHV) power systems. Partial discharge (PD) and local heating can occur in the electrical equipment because of insulation faults, which results in SF6 decomposition and ultimately generates several types of decomposition products. These SF6 decomposition products can be qualitatively and quantitatively detected with relevant detection methods, and such detection contributes ...

  7. Adsorption of SF6 decomposed gas on anatase (101) and (001) surfaces with oxygen defect: A density functional theory study

    Science.gov (United States)

    Zhang, Xiaoxing; Chen, Qinchuan; Tang, Ju; Hu, Weihua; Zhang, Jinbin

    2014-01-01

    The detection of partial discharge by analyzing the components of SF6 gas in gas-insulated switchgears is important to the diagnosis and assessment of the operational state of power equipment. A gas sensor based on anatase TiO2 is used to detect decomposed gases in SF6. In this paper, first-principle density functional theory calculations are adopted to analyze the adsorption of SO2, SOF2, and SO2F2, the primary decomposition by-products of SF6 under partial discharge, on anatase (101) and (001) surfaces. Simulation results show that the perfect anatase (001) surface has a stronger interaction with the three gases than that of anatase (101), and both surfaces are more sensitive and selective to SO2 than to SOF2 and SO2F2. The selection of a defect surface to SO2, SOF2, and SO2F2 differs from that of a perfect surface. This theoretical result is corroborated by the sensing experiment using a TiO2 nanotube array (TNTA) gas sensor. The calculated values are analyzed to explain the results of the Pt-doped TNTA gas sensor sensing experiment. The results imply that the deposited Pt nanoparticles on the surface increase the active sites of the surface and the gas molecules may decompose upon adsorption on the active sites. PMID:24755845

  8. Supershort avalanche electron beam in SF6 and krypton

    Science.gov (United States)

    Zhang, Cheng; Tarasenko, Victor F.; Gu, Jianwei; Baksht, Evgeni Kh.; Beloplotov, Dmitry V.; Burachenko, Alexander G.; Yan, Ping; Lomaev, Mikhail I.; Shao, Tao

    2016-03-01

    Runaway electrons play an important role in the avalanche formation in nanosecond- and subnanosecond- pulse discharges. In this paper, characteristics of a supershort avalanche electron beam (SAEB) generated at the subnanosecond and nanosecond breakdown in sulfur hexafluoride (SF6 ) in an inhomogeneous electric field were studied. One pulser operated at negative polarity with voltage pulse amplitude of ˜130 kV and rise time of 0.3 ns. The other pulser operated at negative polarity with voltage pulse amplitude of 70 kV and rise time of ˜1.6 ns . SAEB parameters in SF6 are compared with those obtained in krypton (Kr), nitrogen (N2 ), air, and mixtures of SF6 with krypton or nitrogen. Experimental results showed that SAEB currents appeared during the rise-time of the voltage pulse for both pulsers. Moreover, amplitudes of the SAEB current in SF6 and Kr approximately ranged from several to tens of milliamps at atmospheric pressure, which were smaller than those in N2 and air (ranging from hundreds of milliamps to several amperes). Furthermore, the concentration of SF6 additive could significantly reduce the SAEB current in N2-SF6 mixture, but it slightly affected the SAEB current in Kr -SF6 mixture because of the atomic/molecular ionization cross section of the gas had a much greater impact on the SAEB current rather than the electronegativity.

  9. An optical sensors for monitoring SF6 dissociation in a corona discharge

    International Nuclear Information System (INIS)

    Irawan, R.; Scelsi, G.B.; Woolsey, G.A.

    1999-01-01

    Sulphur hexafluoride (SF 6 ) is a chemically inert gas (Schumb, 1947) and has high dielectric strength, 3 times greater than air (Morrison and Robins, 1994). In high voltage systems, it is used both as a dielectric and an arc-quenching medium. An electrical breakdown event such as a partial discharge (corona) or arc will dissociate SF 6 into sulphur fluorides, sulphur and fluorine. In a contaminant-free environment, the dissociation products recombine back to SF 6 after extinction of the electrical discharge. Otherwise, some of the products will react with contaminants such as water vapour and oxygen, and with the metal surfaces and electrodes of the discharge chamber, to produce by-products including gaseous sulphur oxyfluorides and solid by-products (Van Brunt, 1985; Griffin et al, 1990 and Vukovic, 1997). As a consequence, a reduction in SF 6 concentration takes place, and the insulating efficiency of the system is degraded. If the SF 6 is not renewed, failure of the high voltage system is likely to eventually occur. One method of monitoring a system is to look for the presence of partial discharges, using techniques such as ultrasonic wave detection (Auckland et al, 1996) or fluorescent plastic fibre (Kurosawa et al., 1997). More directly, the integrity of the SF 6 may be examined using techniques such as mass spectrometry, gas chromatography-mass spectrometry and Fourier Transform Infra-Red Spectroscopy. Such techniques, however, are bulky and require gas samples to be extracted, and so they are unsuited to field use. Since SF 6 insulating systems involve high voltages and a high level of electromagnetic interference, direct in-situ optical monitoring appears to provide the best approach. This paper describes the development of such an optical sensing technique, specifically for continuous monitoring of SF 6 degradation in partial or corona discharges

  10. CF3SF5 : a ‘super’ greenhouse gas

    OpenAIRE

    Tuckett, R. P.

    2008-01-01

    One molecule of the anthropogenic pollutant trifluoromethyl sulphur pentafluoride (CF\\(_3\\)SF\\(_5\\)), an adduct of the CF\\(_3\\) and SF\\(_5\\) free radicals, causes more global warming than one molecule of any other greenhouse gas yet detected in the Earth’s atmosphere. That is, it has the highest per molecule radiative forcing of any greenhouse pollutant, and the value of its global warming potential is only exceeded by that of SF\\(_6\\). First, the greenhouse effect is described, the propertie...

  11. Low energy electron attachment to SF6 in N2, Ar, and Xe buffer gases

    International Nuclear Information System (INIS)

    Hunter, S.R.; Carter, J.G.; Christophorou, L.G.

    1989-01-01

    The electron attachment rate constants k/sub a/ for SF 6 have been measured in dilute mixtures of SF 6 in high pressure (>1 atm) N 2 , Ar, and Xe buffer gases at room temperature (T≅300 K) over a wide E/N range (electric field strength to gas number density ratio), corresponding to mean electron energies from near thermal electron energies (≅0.04 eV) to ≅4.3 eV. Particular attention has been paid to the effects of space charge distortion, molecular impurities, and changes in the electron energy distribution function on the measured electron attachment rate constant values at the lower E/N values in these mixtures. The present measured thermal electron attachment rate constants in SF 6 /N 2 and SF 6 /Xe gas mixtures are in excellent agreement with recent accurate measurements of these parameters in several SF 6 /buffer gas mixtures. At higher values, the present SF 6 /N 2 measurements are in fair agreement with previous measurements, while no previous measurements using Ar and Xe buffer gases have been published. These measurements have been used in numerical two term, spherical harmonic Boltzmann equation analyses of the electron motion in these gas mixtures to obtain the low energy ( 6 . The present derived electron attachment cross sections are compared with recently measured and derived nondissociative and dissociative electron attachment cross sections for SF 6

  12. Parametric investigation on the effect of nitrogen to reduce SF6 content in spark gap

    Science.gov (United States)

    Raj, Avinash; Khaidir, Nur; Ishak, Sanuri; Ghani, Basri Abdul; Chakrabarty, Chandan; Permal, Navitharshaani; Ahmad, Harizan

    2017-03-01

    Almost all the MV and HV switchgears used by power utilities for interrupting faults are Sulphur Hexaflouride SF6 gas circuit breakers as this gas has the best dielectric properties to quench the onset of an arc in the event of fault. However due to strong dissociating properties of this gas when in contact with air that can release fluorine into the atmosphere, the Kyoto protocol has mandated to reduce the usage of SF6 in the future. SF6 is a greenhouse gas and it's about 3000 more severe than CO2. And that's the reason for replacing this gas. A close match in the quenching properties to SF6 that is now being intensively researched is nitrogen N2. This gas is considered to be an inert gas, and its release into the atmosphere has no harmful effects (except for asphyxiation - which can be easily handled with awareness). As the need for a replacement of SF6 becomes critical in the near future, the urgency to find the right gas is immediate. Hence the proposed work in this paper is to make a comprehensive parametric investigation of N2 gas in vacuum spark-gap. The spark-gap is chosen due to flexibility in changing the gap distance and easily be housed in vacuum. The parameters to be investigated are pure N2 and N2/ SF6 mix. The settling-time of the electrical break-down voltage and current are measured using voltage probe and Pearson probe. This time is paramount as it determines the speed of breaking the circuit. A faster breaking time ensures the safety of other HV equipment in the circuit. A comparative study between the various parameters will be conducted to obtain the best recipe (gas mix and gap distance) that gives the shortest settling time the breakdown using N2/ SF6/Mixture gas was successfully conducted and a Paschen curve has been established.

  13. Supershort avalanche electron beam in SF_{6} and krypton

    Directory of Open Access Journals (Sweden)

    Cheng Zhang (章程

    2016-03-01

    Full Text Available Runaway electrons play an important role in the avalanche formation in nanosecond- and subnanosecond- pulse discharges. In this paper, characteristics of a supershort avalanche electron beam (SAEB generated at the subnanosecond and nanosecond breakdown in sulfur hexafluoride (SF_{6} in an inhomogeneous electric field were studied. One pulser operated at negative polarity with voltage pulse amplitude of ∼130  kV and rise time of 0.3 ns. The other pulser operated at negative polarity with voltage pulse amplitude of 70 kV and rise time of ∼1.6  ns. SAEB parameters in SF_{6} are compared with those obtained in krypton (Kr, nitrogen (N_{2}, air, and mixtures of SF_{6} with krypton or nitrogen. Experimental results showed that SAEB currents appeared during the rise-time of the voltage pulse for both pulsers. Moreover, amplitudes of the SAEB current in SF_{6} and Kr approximately ranged from several to tens of milliamps at atmospheric pressure, which were smaller than those in N_{2} and air (ranging from hundreds of milliamps to several amperes. Furthermore, the concentration of SF_{6} additive could significantly reduce the SAEB current in N_{2}-SF_{6} mixture, but it slightly affected the SAEB current in Kr-SF_{6} mixture because of the atomic/molecular ionization cross section of the gas had a much greater impact on the SAEB current rather than the electronegativity.

  14. SF{sub 6} decomposition and layer formation due to excimer laser photoablation of SiO{sub 2} surface at gas-solid system

    Energy Technology Data Exchange (ETDEWEB)

    Sajad, Batool [Physics Department, Amirkabir University, PO Box 15875-4413, Tehran (Iran, Islamic Republic of); Parvin, Parviz [Physics Department, Amirkabir University, PO Box 15875-4413, Tehran (Iran, Islamic Republic of); Bassam, Mohamad Amin [Excimer Laser Lab, Emam Hussain University, PO Box 16575-4347, Tehrann (Iran, Islamic Republic of)

    2004-12-21

    In this work, the effect of an excimer laser has been studied for presenting a method for SF{sub 6} decomposition and simultaneous formation of a SiF{sub 2} layer on amorphous SiO{sub 2}. Though the excimer laser did not establish a gas phase photodissociation, we have shown that UV photoablation leads strongly to molecular decomposition in the SF{sub 6}-SiO{sub 2} system. Moreover, the dependence of the decomposition process on the exposure parameters such as the wavelength and intensity as well as the gas pressure and the focal point distance from the gas-solid interface has been investigated.

  15. 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

  16. Effect of the percentage of SF sub 6 (100%-10%-5%) on the decomposition of SF sub 6 -N sub 2 mixtures under negative dc coronas in the presence of water vapour or oxygen

    CERN Document Server

    Díaz, J; Casanovas, J

    2003-01-01

    Low SF sub 6 content SF sub 6 -N sub 2 mixtures have recently been proposed as a replacement for pure SF sub 6 in the insulation of gas insulated lines (GIL). Among the areas of investigation of such gas mixtures, their electrical decomposition under corona discharges must be studied considering the possible occurrence of such stress in GIL. This paper presents data concerning the decomposition of high-pressure SF sub 6 -N sub 2 (5 : 95) mixtures (400 kPa) submitted to negative dc coronas in the absence or presence of 0.3% H sub 2 O or 0.3% O sub 2. The chemical stability of these mixtures is compared with that of SF sub 6 -N sub 2 (10 : 90) mixtures or undiluted SF sub 6 investigated in the same conditions in a previous paper. The corona discharges were generated with a point-to-plane set-up and the gaseous by-products were assayed by gas chromatography at the end of each run carried out over a range of transported charge covering 0-13 C. The following by-products were detected and assayed: SOF sub 4 , SO su...

  17. Design and fabrication of resonator-quantum well infrared photodetector for SF6 gas sensor application

    Science.gov (United States)

    Sun, Jason; Choi, Kwong-Kit; DeCuir, Eric; Olver, Kimberley; Fu, Richard

    2017-07-01

    The infrared absorption of SF6 gas is narrowband and peaks at 10.6 μm. This narrowband absorption posts a stringent requirement on the corresponding sensors as they need to collect enough signal from this limited spectral bandwidth to maintain a high sensitivity. Resonator-quantum well infrared photodetectors (R-QWIPs) are the next generation of QWIP detectors that use resonances to increase the quantum efficiency for more efficient signal collection. Since the resonant approach is applicable to narrowband as well as broadband, it is particularly suitable for this application. We designed and fabricated R-QWIPs for SF6 gas detection. To achieve the expected performance, the detector geometry must be produced according to precise specifications. In particular, the height of the diffractive elements and the thickness of the active resonator must be uniform, and accurately realized to within 0.05 μm. Additionally, the substrates of the detectors must be completely removed to prevent the escape of unabsorbed light in the detectors. To achieve these specifications, two optimized inductively coupled plasma etching processes were developed. Due to submicron detector feature sizes and overlay tolerance, we used an advanced semiconductor material lithography stepper instead of a contact mask aligner to pattern wafers. Using these etching techniques and tool, we have fabricated focal plane arrays with 30-μm pixel pitch and 320×256 format. The initial test revealed promising results.

  18. Breakdown characteristics of SF6/N2 in severely non-uniform electric fields at low temperatures

    Science.gov (United States)

    Wang, Y.; Gao, Z. W.; Li, G. X.; Zhu, X. C.; Yu, C. L.; Liang, J. Q.; Li, L.

    2018-01-01

    SF6 has good electrical insulating properties, which is widely used as an insulating medium of GIS, GIL and other electrical equipment. However, the reliability of electrical equipments´ insulated gas is greatly challenged in cold areas, since SF6 more readily liquefies. To solve the problem, SF6 can be mixed with N2 to maintain the insulating properties, and reduce its liquefaction temperature. Such practice has certain application prospect. In this paper, a breakdown experimental platform was built to study the insulating property of SF6/N2 at low temperature, wherein the temperature of the platform can be adjusted. A severely non-uniform electric field was generated by a rod-plate electrode. The breakdown characteristics of SF6/N2 with different mixing proportions at low pressures and low temperatures were measured. The result showed that the mixed gas was not liquefied within the temperature range. Temperature had insignificant influence on the insulating property thereof. The result in the paper has certain guiding significance for applying SF6/N2 mixed gas in high latitude areas.

  19. Decomposition of Potent Greenhouse Gases SF6, CF4 and SF5CF3 by Dielectric Barrier Discharge

    International Nuclear Information System (INIS)

    Zhang Renxi; Wang Jingting; Cao Xu; Hou Huiqi

    2016-01-01

    For their distinguished global warming potential (GWP100) and long atmosphere lifespan, CF 4 , SF 6 and SF 5 CF 3 were significant in the field of greenhouse gas research. The details of discharging character and the optimal parameter were discussed by using a Dielectric Barrier Discharge (DBD) reactor to decompose these potent greenhouse gases in this work. The results showed that SF 6 could be decomposed by 92% under the conditions of 5 min resident time and 3000 V applied voltage with the partial pressure of 2.0 kPa, 28.2 kPa, and 1.8 kPa for SF 6 , air and water vapor, respectively. 0.4 kPa CF 4 could be decomposed by 98.2% for 4 min resident time with 30 kPa Ar added. The decomposition of SF 5 CF 3 was much more effective than that of SF 6 and CF 4 and moreover, 1.3 kPa SF 5 CF 3 , discharged with 30 kPa O 2 , Ar and air, could not be detected when the resident time was 80 s, 40 s, and 120 s, respectively. All the results indicated that DBD was a feasible technique for the abatement of potent greenhouse gases. (paper)

  20. Laser excitation of SF6: spectroscopy and coherent pulse propagation effects

    International Nuclear Information System (INIS)

    Cantrell, C.D.; Makarov, A.A.; Louisell, W.H.

    1978-01-01

    Recent theoretical studies of coherent propagation effects in SF 6 and other polyatomic molecules are summarized beginning with an account of relevant aspects of the high-resolution spectroscopy of the ν 3 band of SF 6 . A laser pulse propagating in a molecular gas can acquire new frequencies which were not initially present in the pulse, and, in fact, a wave is coherently generated at the frequency of every molecular transition accessible from the initial molecular energy levels. The possible consequences of coherent generation of sidebands for the multiple-photon excitation of SF 6 and other polyatomic molecules are discussed

  1. Theoretical investigation of the decay of an SF6 gas-blast arc using a two-temperature hydrodynamic model

    International Nuclear Information System (INIS)

    Wang Weizong; Rong Mingzhe; Yan, Joseph D; Spencer, Joseph W; Murphy, Anthony B

    2013-01-01

    The behaviour of a decaying SF 6 arc, which is representative of the approach to the final current-zero state of switching arcs in a high-voltage circuit breaker, is theoretically investigated by a two-temperature hydrodynamic model, taking into account the possible departure of the plasma state from local thermodynamic equilibrium (LTE). The model couples the plasma flow with electromagnetic fields in a self-consistent manner. The electrons and heavy species are assumed to have different temperatures. The species composition, thermodynamic properties and transport coefficients of the plasma under non-LTE conditions are calculated from fundamental theory. The model is then applied to a two-dimensional axisymmetric SF 6 arc burning in a supersonic nozzle under well-controlled conditions; for this configuration, experimental results are available for comparison. The effect of turbulence is considered using the Prandtl mixing-length model. The edge absorption of the radiation emitted by the arc core is taken into account by a modified net emission coefficient approach. The complete set of conservation equations is discretized and solved using the finite volume method. The evolution of electron and heavy-particle temperatures and the total arc resistance, along with other physical quantities, is carefully analysed and compared with those of the LTE case. It is demonstrated that the electron and heavy-particle temperature diverge at all times in the plasma-cold-flow interaction region, in which strong gas flow exists, and further in the transient current-zero period, in which case the collision energy exchange is ineffective. This study quantitatively analyses the energy exchange mechanisms between electrons and heavy particles in the high-pressure supersonic SF 6 arcs and provides the foundation for further theoretical investigation of transient SF 6 arc behaviour as the current ramps down to zero in gas-blast circuit breakers.

  2. Efficient removal of sulfur hexafluoride (SF6) through reacting with recycled electroplating sludge.

    Science.gov (United States)

    Zhang, Jia; Zhou, Ji Zhi; Liu, Qiang; Qian, Guangren; Xu, Zhi Ping

    2013-06-18

    This paper reports that recycled electroplating sludge is able to efficiently remove greenhouse gas sulfur hexafluoride (SF6). The removal process involves various reactions of SF6 with the recycled sludge. Remarkably, the sludge completely removed SF6 at a capacity of 1.10 mmol/g (SF6/sludge) at 600 °C. More importantly, the evolved gases were SO2, SiF4, and a limited amount of HF, with no toxic SOF4, SO2F2, or SF4 being detected. These generated gases can be readily captured and removed by NaOH solution. The reacted solids were further found to be various metal fluorides, thus revealing that SF6 removal takes place by reacting with various metal oxides and silicate in the sludge. Moreover, the kinetic investigation revealed that the SF6 reaction with the sludge is a first-order chemically controlled process. This research thus demonstrates that the waste electroplating sludge can be potentially used as an effective removal agent for one of the notorious greenhouse gases, SF6.

  3. Two-temperature transport coefficients of SF6–N2 plasma

    International Nuclear Information System (INIS)

    Yang, Fei; Chen, Zhexin; Wu, Yi; Rong, Mingzhe; Wang, Chunlin; Guo, Anxiang; Liu, Zirui

    2015-01-01

    Sulfur hexafluoride (SF 6 ) is widely adopted in electric power industry, especially in high-voltage circuit breakers and gas-insulated switchgear. However, the use of SF 6 is limited by its high liquidation temperature and high global warming potential. Recently, research shows SF 6 –N 2 mixture, which shows environmental friendliness and good electrical properties, may be a feasible substitute for pure SF 6 . This paper is devoted to the calculation of and transport coefficients of SF 6 –N 2 mixture under both LTE (local thermodynamic equilibrium) and non-LTE condition. The two–temperature mass action law was used to determine the composition. The transport coefficients were calculated by classical Chapman–Enskog method simplified by Devoto. The thermophysical properties are presented for electron temperatures of 300–40 000 K, ratios of electron to heavy species temperature of 1–10 and N 2 mole fraction of 0%–100% at atmospheric pressure. The ionization processes under both LTE and non-LTE have been discussed. The results show that deviations from local thermodynamic equilibrium significantly affect the properties of SF 6 –N 2 plasma, especially before the plasma is fully ionized. The different influence of N 2 on properties for SF 6 –N 2 plasma in and out of LTE has been found. The results will serve as reliable reference data for computational simulation of the behavior of SF 6 –N 2 plasmas

  4. SF6 ventilation study at Agnew Lake Mines, Ontario

    International Nuclear Information System (INIS)

    1979-03-01

    In September 1978, James F. MacLaren Limited was awarded a contract by the Canada Centre for Mineral and Energy Technology (CANMET) to undertake a ventilation study at an underground uranium mine using sulphur hexafluoride (SF 6 ) as a tracer gas. The mine selected for the study was that of Agnew Lake Mines Limited in Northern Ontario. This is a relatively new mine with the combined mine/mill facilities first operational in mid-1977. Uranium is recovered from broken ore by in-situ leaching. The ventilation study was divided into two phases. A laboratory study was undertaken to develop a practical sampling technique, provide an evaluation of the logistics of long range sample transport and develop a laboratory analytical technique. Field programmes demonstrated the SF 6 tracer gas technique for mine ventilation trouble-shooting with the intent of providing information which will lead to more efficient use of existing mine ventilation capacity. This report outlines the findings of the laboratory study and the two field programmes

  5. Negative corona current pulses in argon and in mixture argon with SF6

    International Nuclear Information System (INIS)

    Zahoranova, A.; Zahoran, M.; Bucek, A.; Cernak, M.; Bosko, J.

    2004-01-01

    Waveforms of the first negative current pulses in a short negative point-to plane gap in pure argon and argon with SF 6 admixture have been investigated with a nanosecond time resolution at a gas pressure 50 kPa as a function of applied gap voltage and content of SF 6 in the mixture. We have made an attempt to explain the differences in the discharge development in pure argon and in argon with admixture of SF 6 based on the observed changes of the pulse shape. The experimental results obtained will be discussed in context with existing computer simulation models (Authors)

  6. Analysis of the characteristics of DC nozzle arcs in air and guidance for the search of SF6 replacement gas

    Science.gov (United States)

    Liu, J.; Zhang, Q.; Yan, J. D.; Zhong, J.; Fang, M. T. C.

    2016-11-01

    It is shown that the arc model based on laminar flow cannot predict satisfactorily the voltage of an air arc burning in a supersonic nozzle. The Prandtl mixing length model (PML) and a modified k-epsilon turbulence model (MKE) are used to introduce turbulence enhanced momentum and energy transport. Arc voltages predicted by these two turbulence models are in good agreement with experiments at the stagnation pressure (P 0) of 10 bar. The predicted arc voltages by MKE for P 0  =  13 bar and 7 bar are in better agreement with experiments than those predicted by PML. MKE is therefore a preferred turbulence model for an air nozzle arc. There are two peaks in ρC P of air at 4000 K and 7000 K due, respectively, to the dissociation of oxygen and that of nitrogen. These peaks produce corresponding peaks in turbulent thermal conductivity, which results in very broad radial temperature profile and a large arc radius. Thus, turbulence indirectly enhances axial enthalpy transport, which becomes the dominant energy transport process for the overall energy balance of the arc column at high currents. When the current reduces, turbulent thermal conduction gradually becomes dominant. The temperature dependence of ρC P has a decisive influence on the radial temperature profile of a turbulent arc, thus the thermal interruption capability of a gas. Comparison between ρC P for air and SF6 shows that ρC P for SF6 has peaks below 4000 K. This renders a distinctive arc core and a small arc radius for turbulent SF6, thus superior arc quenching capability. It is suggested, for the first time, that ρC P provides guidance for the search of a replacement switching gas for SF6.

  7. A single gas chromatograph for accurate atmospheric mixing ratio measurements of CO2, CH4, N2O, SF6 and CO

    NARCIS (Netherlands)

    van der Laan, S.; Neubert, R. E. M.; Meijer, H. A. J.; Simpson, W.R.

    2009-01-01

    We present an adapted gas chromatograph capable of measuring simultaneously and semi-continuously the atmospheric mixing ratios of the greenhouse gases CO2, CH4, N2O and SF6 and the trace gas CO with high precision and long-term stability. The novelty of our design is that all species are measured

  8. Abnormal polarity effect in nanosecond-pulse breakdown of SF6 and nitrogen

    International Nuclear Information System (INIS)

    Shao, Tao; Tarasenko, Victor F.; Zhang, Cheng; Beloplotov, Dmitry S.; Yang, Wenjin; Lomaev, Mikhail I.; Zhou, Zhongsheng; Sorokin, Dmitry A.; Yan, Ping

    2014-01-01

    The breakdown of gas gaps in an inhomogeneous electric field at subnanosecond and nanosecond voltage pulse rise times are studied, and the famous polarity effect in point-to-plane gaps is investigated. It is shown that at a voltage pulse rise time of ∼0.5 ns, the inversion of polarity effect takes place not only in electronegative gases such as SF 6 , but also occurs in electropositive nitrogen. The inversion of polarity effect is related to a delay of electron emission from the plane cathode on arrival of the ionization wave front anode to the cathode. It is found that with a voltage pulse rise time of ∼0.5 ns, the inversion of polarity effect occurs at SF 6 and SF 6 –N 2 pressures of 0.25 MPa and lower, and with a voltage pulse rise time of 15 ns, at a SF 6 pressure lower than 0.12 MPa.

  9. Present and future environmental ''problems'' with SF6 and other fluorinated gases

    International Nuclear Information System (INIS)

    Brunt, R.J. Van

    1996-01-01

    Sulfur hexafluoride (SF 6 ) is widely used as an insulating and arc interrupting gas in high-voltage systems and has found application in plasma processing of materials. However, SF 6 is known to decompose in electrical discharges to form toxic and corrosive gaseous compounds such as SOF 4 , SOF 2 , SO 2 F 2 , and HF. Of particular concern are the species S 2 F 10 and S 2 O 2 F 10 that are known to be highly toxic and to be formed in corona, spark, and arc discharges in high-pressure SF 6 . The conditions under which these byproducts are formed, the methods for removal, and the possible hazards that they present are reviewed. Sulfur hexafluoride is also an efficient absorber of infrared radiation and is estimated to have a global warning potential that is 2.5 x 10 4 times greater than that of CO 2 . Methods that have been proposed to control the use of SF 6 and reduce the rate of its release into the atmosphere will be examined. The advantages, disadvantages, and likely problems with finding technically feasible and environmentally acceptable replacements for SF 6 will be discussed

  10. Electron Transport Coefficients and Effective Ionization Coefficients in SF6-O2 and SF6-Air Mixtures Using Boltzmann Analysis

    Science.gov (United States)

    Wei, Linsheng; Xu, Min; Yuan, Dingkun; Zhang, Yafang; Hu, Zhaoji; Tan, Zhihong

    2014-10-01

    The electron drift velocity, electron energy distribution function (EEDF), density-normalized effective ionization coefficient and density-normalized longitudinal diffusion velocity are calculated in SF6-O2 and SF6-Air mixtures. The experimental results from a pulsed Townsend discharge are plotted for comparison with the numerical results. The reduced field strength varies from 40 Td to 500 Td (1 Townsend=10-17 V·cm2) and the SF6 concentration ranges from 10% to 100%. A Boltzmann equation associated with the two-term spherical harmonic expansion approximation is utilized to gain the swarm parameters in steady-state Townsend. Results show that the accuracy of the Boltzmann solution with a two-term expansion in calculating the electron drift velocity, electron energy distribution function, and density-normalized effective ionization coefficient is acceptable. The effective ionization coefficient presents a distinct relationship with the SF6 content in the mixtures. Moreover, the E/Ncr values in SF6-Air mixtures are higher than those in SF6-O2 mixtures and the calculated value E/Ncr in SF6-O2 and SF6-Air mixtures is lower than the measured value in SF6-N2. Parametric studies conducted on these parameters using the Boltzmann analysis offer substantial insight into the plasma physics, as well as a basis to explore the ozone generation process.

  11. EPA's SF6 Emission Reduction Partnership: Maximizing the Benefits of SF6 Emission Reductions for Electric Utilities

    National Research Council Canada - National Science Library

    Blackman, Jerome; Kantamaneni, Ravi

    2004-01-01

    .... Under ideal conditions, SF6 would remain contained within transmission equipment. In reality, however, SF6 is inadvertently emitted into the atmosphere as leaks develop during various stages of the equipment's life cycle...

  12. Two-temperature transport coefficients of SF{sub 6}–N{sub 2} plasma

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Fei; Chen, Zhexin; Wu, Yi, E-mail: wuyic51@mail.xjtu.edu.cn; Rong, Mingzhe; Wang, Chunlin [State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Guo, Anxiang; Liu, Zirui [Electric Power Research Institute of State Grid Shaanxi Electric Power Company, Xian (China)

    2015-10-15

    Sulfur hexafluoride (SF{sub 6}) is widely adopted in electric power industry, especially in high-voltage circuit breakers and gas-insulated switchgear. However, the use of SF{sub 6} is limited by its high liquidation temperature and high global warming potential. Recently, research shows SF{sub 6}–N{sub 2} mixture, which shows environmental friendliness and good electrical properties, may be a feasible substitute for pure SF{sub 6}. This paper is devoted to the calculation of and transport coefficients of SF{sub 6}–N{sub 2} mixture under both LTE (local thermodynamic equilibrium) and non-LTE condition. The two–temperature mass action law was used to determine the composition. The transport coefficients were calculated by classical Chapman–Enskog method simplified by Devoto. The thermophysical properties are presented for electron temperatures of 300–40 000 K, ratios of electron to heavy species temperature of 1–10 and N{sub 2} mole fraction of 0%–100% at atmospheric pressure. The ionization processes under both LTE and non-LTE have been discussed. The results show that deviations from local thermodynamic equilibrium significantly affect the properties of SF{sub 6}–N{sub 2} plasma, especially before the plasma is fully ionized. The different influence of N{sub 2} on properties for SF{sub 6}–N{sub 2} plasma in and out of LTE has been found. The results will serve as reliable reference data for computational simulation of the behavior of SF{sub 6}–N{sub 2} plasmas.

  13. Impact of 10% SF6 Gas Compared to 100% Air Tamponade in Descemet's Membrane Endothelial Keratoplasty.

    Science.gov (United States)

    Rickmann, Annekatrin; Szurman, Peter; Jung, Sacha; Boden, Karl Thomas; Wahl, Silke; Haus, Arno; Boden, Katrin; Januschowski, Kai

    2018-04-01

    To compare the clinical outcomes following Descemet's membrane endothelial keratoplasty (DMEK) with 100% air tamponade versus 10% sulfur hexafluoride (SF 6 ) tamponade. Retrospective analysis of 108 consecutive DMEK cases subdivided by anterior chamber tamponade with 54 eyes receiving 10% SF 6 and 54 eyes receiving 100% air injection. A post-hoc matched analysis revealed no statistically significant differences between the groups. The main outcome measurements were the complication rate, including intra- and postoperative complications and graft detachment rate requiring re-bubbling. Clinical outcome included best-corrected visual acuity (BCVA), endothelial cell count (ECC), and central corneal thickness (CCT) measured 1, 3, and 6 months after DMEK surgery. The graft detachment rate with consecutive re-bubbling was 18.5% in the air group and 22.2% in the SF 6 group (p = 0.2). Remaining small peripheral graft detachments with a clear cornea occurred more often in the 100% air group (air: 22.2%; 12/54, 6/12 inferior compared to SF 6 : 7.4%; 4/54, 2/4 inferior; p = 0.06). The primary graft failure rate was comparable between the two groups. No complete graft detachment occurred. Outcome results for BCVA, ECC, and CCT at all follow-up time points were comparable between the two groups. The clinical outcomes (including re-bubbling rate, primary graft failure rate, and endothelial cell loss) were comparable with 100% air versus 10% SF 6 tamponade, whereas other studies suggest that a higher SF 6 concentration (20%) may result in a lower re-bubbling rate.

  14. A novel method to decompose two potent greenhouse gases: Photoreduction of SF6 and SF5CF3 in the presence of propene

    International Nuclear Information System (INIS)

    Huang Li; Shen Yan; Dong Wenbo; Zhang Renxi; Zhang Jianliang; Hou Huiqi

    2008-01-01

    SF 5 CF 3 and SF 6 are the most effective greenhouse gases on a per molecule basis in the atmosphere. Original laboratory trial for photoreduction of them by use of propene as a reactant was performed to develop a novel technique to destroy them. The highly reductive radicals produced during the photolysis of propene at 184.9 nm, such as ·CH 3 , ·C 2 H 3 , and ·C 3 H 5 , could efficiently decompose SF 6 and SF 5 CF 3 to CH 4 , elemental sulfur and trace amounts of fluorinated organic compounds. It was further demonstrated that the destruction and removal efficiency (DRE) of SF 5 X (X represented F or CF 3 ) was highly dependent on the initial propene-to-SF 5 X ratio. The addition of certain amounts of oxygen and water vapor not only enhanced the DRE but avoided the generation of deposits. In both systems, employment nitrogen as dilution gas lessened the DRE slightly. Given the advantage of less toxic products, the technique might contribute to SF 5 X remediation

  15. Electron-transport, ionization, attachment, and dissociation coefficients in SF6 and its mixtures

    International Nuclear Information System (INIS)

    Phelps, A.V.; Van Brunt, R.J.

    1988-01-01

    An improved set of electron-collision cross sections is derived for SF 6 and used to calculate transport, ionization, attachment, and dissociation coefficients for pure SF 6 and mixtures of SF 6 with N 2 , O 2 , and Ne. The SF 6 cross sections differ from previously published sets primarily at very low and high electron energies. At energies below 0.03 eV the attachment cross section is adjusted to fit recent electron swarm experiments, while the elastic momentum transfer cross section is increased to the theoretical limit. At high energies an allowance is made for the excitation of highly excited levels as observed in electron beam experiments. The cross-section sets used for the admixed gases have previously been published. Electron kinetic energy distributions computed from numerical solutions of the electron-transport (Boltzmann) equation using the two-term, spherical harmonic expansion approximation were used to obtain electron-transport and reaction coefficients as functions of E/N and the fractional concentration of SF 6 . Here E is the electric field strength and N is the gas number density. Attachment rate data for low concentrations of SF 6 in N 2 are used to test the attachment cross sections. Particular attention is given to the calculation of transport and reaction coefficients at the critical E/N = (E/N)/sub c/ at which the ionization and attachment rates are equal

  16. Gas exchange rates measured using a dual-tracer (SF6 and3he) method in the coastal waters of Korea

    Science.gov (United States)

    Lee, Hyun-Woo; Lee, Kitack; Kaown, Duk-In

    2008-03-01

    Over a period of 5 days between August 12 and 17, 2005, we performed a gas exchange experiment using the dual tracer method in a tidal coastal ocean located off the southern coast of Korea. The gas exchange rate was determined from temporal changes in the ratio of3He to SF6 measured daily in the surface mixed layer. The measured gas exchange rate ( k CO 2), normalized to a Schmidt number of 600 for CO2 in fresh water at 20°C, was approximately 5.0 cm h-1 at a mean wind speed of 3.9 m s-1 during the study period. This value is significantly less than those obtained from floating chamber-based experiments performed previously in estuarine environments, but is similar in magnitude to values obtained using the dual tracer method in river and tidal coastal waters and values predicted on the basis of the relationship between the gas exchange rate and wind speed (Wanninkhof 1992), which is generally applicable to the open ocean. Our result is also consistent with the relationship of Raymond and Cole (2001), which was derived from experiments carried out in estuarine environments using222Rn and chlorofluorocarbons along with measurements undertaken in the Hudson River, Canada, using SF6 and3He. Our results indicate that tidal action in a microtidal region did not discernibly enhance the measured k CO 2 value.

  17. Decomposition of SF6-R134a effluents by RF plasma

    International Nuclear Information System (INIS)

    Joshi, Avinash V.

    2012-01-01

    The efficiency of recovery achieved by open or closed loop extraction of RPC exhaust gases is in the range of 90-95% under optimum conditions. For a large detector setup operating on one volume change per day basis, a 5% loss amounts to discharging 50 kg of R134a and 0.5 kg of SF 6 into atmosphere every day. The emissions are equivalent to create nearly 50 000 m 3 of carbon dioxide daily. The gas emissions need to be completely converted to safer compounds. The gases such as R134a and SF 6 are stable compounds. In order to decompose these, the mixture is first activated by adding of 50% oxygen and 2% argon and under typical RF plasma conditions of 13.56 MHz, 1 Torr pressure and 0.2 W/cm 2 power density. The chemical reaction takes place on the surface of a silicon electrode. The product of the reaction is mainly SiF 4 (gas), which is further hydrolyzed to form HF solution and silicon hydroxide sludge. More than 90% of the effluent gas mixture can be effectively removed by this method.

  18. Verification of the sputter-generated {sup 32}SF{sub n}{sup −} (n = 1–6) anions by accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Mane, R.G.; Surendran, P. [Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kumar, Sanjay [Physics Department, Agra College Agra, Agra 282002 (India); Nair, J.P.; Yadav, M.L. [Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Hemalatha, M. [UM-DAE Centre for Excellence in Basic Sciences, Mumbai 400098 (India); Thomas, R.G.; Mahata, K. [Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kailas, S. [UM-DAE Centre for Excellence in Basic Sciences, Mumbai 400098 (India); Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Gupta, A.K., E-mail: anit@tifr.res.in [Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2016-01-01

    Recently, we have performed systematic Secondary Ion Mass Spectrometry (SIMS) measurements at our ion source test set up and have demonstrated that gas phase {sup 32}SF{sub n}{sup −} (n = 1–6) anions for all size ‘n’ can be readily generated from a variety of surfaces undergoing Cs{sup +} ion sputtering in the presence of high purity SF{sub 6} gas by employing the gas spray-cesium sputter technique. In our SIMS measurements, the isotopic yield ratio {sup 34}SF{sub n}{sup −}/{sup 32}SF{sub n}{sup −} (n = 1–6) was found to be close to its natural abundance but not for all size ‘n’. In order to gain further insight into the constituents of these molecular anions, ultra sensitive Accelerator Mass Spectrometry (AMS) measurements were conducted with the most abundant {sup 32}SF{sub n}{sup −} (n = 1–6) anions, at BARC-TIFR 14 UD Pelletron accelerator. The results from these measurements are discussed in this paper.

  19. BOREAS TGB-1 NSA SF6 Chamber Flux Data

    Science.gov (United States)

    Crill, Patrick; Varner, Ruth K.; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor)

    2000-01-01

    The BOREAS TGB-1 team made several chamber and tower measurements of trace gases at sites in the BOREAS NSA. This data set contains sulfur hexafluoride (SF6) dark chamber flux measurements at the NSA-OJP and NSA-YJP sites from 16-May through 13-Sep-1994. Gas samples were extracted approximately every 7 days from dark chambers and analyzed at the NSA lab facility. The data are provided in tabular ASCII files.

  20. Screening test of relays used under pressurized sulfur hexafluoride (SF6)

    International Nuclear Information System (INIS)

    Kutsukake, Kenichi; Matsuda, Makoto; Hanashima, Susumu; Obara, Kenjiro

    2008-01-01

    Many measurement and control devices inside of a high voltage terminal of the JAEA-Tokai tandem accelerator are operated under pressurized sulfur hexafluoride gas (SF 6 ) of 0.5 MPa. This screening test has been carried out to select a relay, which is usable under the pressurized SF 6 for turn on and off a large current of the devices, from commercial relays used in the atmospheric condition. Four kinds of relays were tested: electromechanical relay (EMR), magnet contactor (MAG), solid-state relay (SSR) and hybrid relay (HYB). Temperature and appearance changes of the relay were collected as measurement items. In addition, a reason of contact trouble of the relays was considered from the results of qualitative elementary analysis and observation of the contact surface using the EDS (energy-dispersive X-ray spectroscopy) and the SEM (scanning electron microscope). As a result, the EMR and the MAG showed irregular contact in spite of input voltage and electric current had fed to an operational coil of the relay normally. It is caused by the sulfide or fluoride compounds, which were formed by chemical reaction between metals and sulfur or hydrogen fluoride due to dissociation of SF 6 in electric arcs. On the other hand, the performance of the SSR and the HYB is better than the EMR and the MAG, and it was found that these relays are available in the pressurized SF 6 of 0.5MPa in spite of the standard specification. (author)

  1. Comprehensive Study of SF_6/O_2 Plasma Etching for Mc-Silicon Solar Cells

    International Nuclear Information System (INIS)

    Li Tao; Zhou Chun-Lan; Wang Wen-Jing

    2016-01-01

    The mask-free SF_6/O_2 plasma etching technique is used to produce surface texturization of mc-silicon solar cells for efficient light trapping in this work. The SEM images and mc-silicon etching rate show the influence of plasma power, SF_6/O_2 flow ratios and etching time on textured surface. With the acidic-texturing samples as a reference, the reflection and IQE spectra are obtained under different experimental conditions. The IQE spectrum measurement shows an evident increase in the visible and infrared responses. By using the optimized plasma power, SF_6/O_2 flow ratios and etching time, the optimal efficiency of 15.7% on 50 × 50 mm"2 reactive ion etching textured mc-silicon silicon solar cells is achieved, mostly due to the improvement in the short-circuit current density. The corresponding open-circuit voltage, short-circuit current density and fill factor are 611 mV, 33.6 mA/cm"2, 76.5%, respectively. It is believed that such a low-cost and high-performance texturization process is promising for large-scale industrial silicon solar cell manufacturing. (paper)

  2. Abatement cost of SF6 emissions from medium voltage switchgear. Validation of recent studies for the European Commission

    Energy Technology Data Exchange (ETDEWEB)

    Benner, J.; Van Lieshout, M.; Croezen, H.

    2012-05-15

    Sulphur hexafluoride (SF6) is a gas with applications including use as an insulator and switching medium in medium voltage (MV) switchgear. While having certain unique properties, it is also a greenhouse gas, with a 22,800 times greater impact than CO2 and an atmospheric lifetime of over 3,000 years. Although the use of SF6 in MV switchgear can be avoided, according to recent studies for the European Commission, the abatement costs are high. This study validates the calculated cost levels as well as the general feasibility of determining a fixed cost figure for this purpose. This analysis yields a result which differs from the earlier studies, particularly with respect to the cost aspect, but also in other areas. CE Delft concludes that for the majority of applications cost-effective SF6-free options are available, leading to abatement costs for the use of SF6 in MV switchgear that range from - 40 to 0 euro/tCO2 eq., for all types of switchgear, with voltage levels below 25 kV and situated on relatively dry locations.

  3. Gas-filled hohlraum fabrication

    International Nuclear Information System (INIS)

    Salazar, M.A.; Gobby, P.L.; Foreman, L.R.; Bush, H. Jr.; Gomez, V.M.; Moore, J.E.; Stone, G.F.

    1995-01-01

    Los Alamos National Laboratory (LANL) researchers have fabricated and fielded gas-filled hohlraums at the Lawrence Livermore National Laboratory (LLNL) Nova laser. Fill pressures of 1--5 atmospheres have been typical. We describe the production of the parts, their assembly and fielding. Emphasis is placed on the production of gas-tight polyimide windows and the fielding apparatus and procedure

  4. Evaluation of SF6-alternative gas C5-PFK based on arc extinguishing performance and electric strength

    Science.gov (United States)

    Wu, Yi; Wang, Chunlin; Sun, Hao; Rong, Mingzhe; Murphy, Anthony Bruce; Li, Tianwei; Zhong, Jianying; Chen, Zhexin; Yang, Fei; Niu, Chunpin

    2017-09-01

    C5-PFK (C5-perfluoroketone, C5F10O) is under wide consideration as an environmentally-friendly alternative gas to SF6 in high-voltage applications, because of its superior insulation performance. The aim of this work is to study theoretically the arc extinguishing performance and electric strength of C5-PFK. The arc extinguishing performance of C5-PFK was evaluated by analyzing and comparing the thermophysical properties of C5-PFK, SF6, CF4, CO2 and N2 plasmas. It was difficult to obtain the species formed in C5-PFK plasmas because of the complex C5-PFK molecular decomposition process. In this work, the decomposition process of C5-PFK and the related species were analyzed by the bond energy analysis method. For the species for which parameters such as the partition function and the enthalpy of formation were not available, computational chemistry methods were used to obtain the required data. The collision integrals were calculated using the phenomenological potential model. Using these results, the local thermodynamic equilibrium composition at temperatures from 300 to 30 000 K at 1-10 atm of pure C5-PFK was calculated by the method of minimization of the Gibbs free energy, and the corresponding transport coefficients were calculated by Chapman-Enskog method. Through the comparison of the thermophysical properties, it was found that C5-PFK had similar characteristics to SF6, with large peaks in specific heat below 4500 K, indicating potentially good thermal interruption capability. However, the specific heat peak at 7000 K corresponding to CO decomposition may detract from the thermal interruption capability. Specific heat peaks at higher temperatures are associated with the breaking of double or triple bonds, and should be avoided if possible in the new alternative gases. The electric strength of C5-PFK was assessed using the molecular electrostatic potential, which can be accurately calculated or measured, and gives strong insights into important

  5. The sensing mechanism of N-doped SWCNTs toward SF6 decomposition products: A first-principle study

    Science.gov (United States)

    Gui, Yingang; Tang, Chao; Zhou, Qu; Xu, Lingna; Zhao, Zhongyong; Zhang, Xiaoxing

    2018-05-01

    In order to monitor the insulation status of SF6-insulated equipment on-line, SOF2 and SO2F2, two typical decomposition products of SF6 under electric discharge condition, are chosen as the target gases to evaluate the type and severity of discharge. In this work, single N atom doping method is adopted to improve the gas sensitivity of single wall carbon nanotubes to SOF2 and SO2F2. Single and double gas molecules adsorptions are considered to completely analyze the adsorption properties of N-doped single wall carbon nanotubes. Calculation results show that N atom doping enhances the surface activity of carbon nanotubes. When gas molecules physically adsorbed on N-doped single wall carbon nanotubes, the weak interaction between gas molecules and N-doped single wall carbon nanotubes nearly not changes the electrical property according to analysis of the density of states and molecular orbitals. While the chemisorption between gas molecules and N-doped single wall carbon nanotubes distinctly decreases the conductivity of adsorption system.

  6. Bush moves to bolster U.S. industry

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This paper reports that President Bush, in an election campaign appearance in Oklahoma City, the his administration is taking several steps to help the U.S. oil industry. Bush the, I known full well how difficult times have been in the past few years in this state for the oil and gas business. Our domestic oil and gas industry is important to our national economy. It's important, it's vital, to our national security. Bush vowed to work with Congress for passage of an omnibus energy policy bill and to get the oil industry some relief from the alternative minimum tax. The AMT, as applied to the energy industry, is hurting our economy and helping no one, Bush the. It is unfair to independent producers. And it's costing us jobs

  7. Leader propagation in uniform background fields in SF6

    International Nuclear Information System (INIS)

    Seeger, M; Niemeyer, L; Bujotzek, M

    2009-01-01

    The breakdown mechanism of compressed SF 6 in gas insulation is known to be controlled by stepped leader propagation. This process is still not well understood in uniform and weakly non-uniform background fields with small electrode protrusions, such as particles or surface roughness. In a previous publication an investigation of partial discharges and breakdown in uniform background fields that focused on streamer and leader inception mechanisms was presented (Seeger et al 2008 J. Phys. D: Appl. Phys. 41 185204). In this paper we present for the first time a physical leader propagation model that consistently describes the observed phenomena in uniform background fields in SF 6 . The model explains two different types of leader breakdown; these can be associated with the precursor and the stem mechanisms. It also yields the parameters of stepped leader propagation, which include step lengths, associated step charges, step times and fields and temperatures in the leader channel. Further, it explains the features of arrested leaders in uniform background fields. The model predicts the range of parameters under which arrested and breakdown leaders occur in good agreement with the experimental data.

  8. Electric Field and Current Density Performance Analysis of Sf6, C4f8 and CO2 Gases As An Insulation

    Science.gov (United States)

    Mazli, Ahmad Danial Ahmad; Jamail, Nor Akmal Mohd; Azlin Othman, Nordiana

    2017-08-01

    SF6 gases are not only widely used as an insulating component in electric power industry but also as an arc extinguishing performance in high voltage (HV) gas-insulated circuit breaker (GCB). SF6 gases is generally used in the production of semiconductor materials and devices. Though these gasses is widely used in many application, the presences of temperature hotspot in the insulations may affect the insulation characteristics particularly electric field and current density. Therefore, it is important to determine the relationship between electric field and current density of gasses used in the insulator in the presence of hotspot. In this paper, three types of gases in particular Sulphur Hexafluoride (SF6), Octafluorocylobutane (C4F8), and Carbon Dioxide (CO2) was used in the insulator for gas insulation with the presence of two hotspots. These two hotspost were detected by referring the rising temperature in the insulator which are 1000 and 2000 Kelvin temperature for hotspot 1 and hotspot 2, respectively. From the simulation results, it can be concluded that Sulphur Hexafluoride (SF6) is the best choice for gas insulation since it had the lowest current density and electric field compared to Octafluorocylobutane (C4F8), and Carbon Dioxide (CO2). It is observed that the maximum current density and electric field for SF6 during normal condition are 358.94 × 103 V/m and 0.643 × 109 A/m2, respectively. Meanwhile, during temperature rising at hotspot 1 and hotspot 2, SF6 also had lowest current density and electric field compared to the other gasses where the results for Emax and Jmax at hotspot 1 are 322.34 × 103 V/m and 1.934 × 109 A/m2, respectively; While, Emax and Jmax at hotspot 2 are 259.77× 103 V/m and 2.824 × 109 A/m2. The results of this analysis can be used to find the best choices of gas that can be used in the insulator.

  9. Self-focusing in SF6

    International Nuclear Information System (INIS)

    Ackerhalt, J.R.; Galbraith, H.W.

    1981-01-01

    It is shown by explicit calculation of previously published quasicontinuum model that the molecular susceptibility rapidly approaches zero as higher excited states of the molecule become populated. Hence the overtones of the ν 3 -pumped mode are totally responsible for the self focusing effects in SF 6 . The ν 3 ladder contribution to the susceptibility is calculated. The vibrational model is a classical triply degenerate anharmonic oscillator in the Cartesian basis with the anharmonicity parameters chosen to be consistent with the latest spectroscopic analysis of the 3ν 3 overtone spectrum. The rotational structure is represented by a distribution of these oscillators where the distribution is chosen to correspond to the spectrum of the ν 3 fundamental. Good agreement is found with the 300 0 in self-focusing data of Nowak and Ham at CO 2 P(28), P(20) and P(10) in SF 6

  10. Development of a compact bushing for NBI

    Science.gov (United States)

    de Esch, H. P. L.; Simonin, A.; Grand, C.; Lepetit, B.; Lemoine, D.; Márquez-Mijares, M.; Minea, T.; Caillault, L.; Seznec, B.; Jager, T.; Odic, E.; Kirkpatrick, M. J.; Teste, Ph.; Dessante, Ph.; Almaksour, K.

    2017-08-01

    Research into a novel type of compact bushing is being conducted through the HVIV (High Voltage holding In Vacuum) partnership between CEA-Cadarache1, GeePs-Centralesupélec4, LPGP3 and LCAR2. The bushing aims to concentrate the high electric field inside its interior, rather than in the vacuum tank. Hence the field emission current is also concentrated inside the bushing and it can be attempted to suppress this so-called dark current by conditioning the internal surfaces and by adding gas. LCAR have performed theoretical quantum mechanical studies of electron field emission and the role of adsorbates in changing the work function. LPGP studied the ionization of gas due to field emission current and the behavior of micro particles exposed to emissive electron current in the vacuum gap under high electric fields. Experiments at Geeps have clarified the role of surface conditioning in reducing the dark current. Geeps also found that adding low pressure nitrogen gas to the vacuum is much more effective than helium in reducing the field emission. An interesting observation is the growth of carbon structures after exposure of an electrode to the electric field. Finally, IRFM have performed experiments on a single stage test bushing that features a 36 cm high porcelain insulator and two cylindrical electrode surfaces in vacuum or low-pressure gas. Using 0.1 Pa N2 gas, the voltage holding exceeded 185 kV over a 40 mm "vacuum" gap without dark current. Above this voltage, exterior breakdowns occurred over the insulator, which was in air. The project will finish with the fabrication of a 2-stage compact bushing, capable to withstand 400 kV.

  11. Insights into the dynamics of in situ gas hydrate formation and dissociation at the Bush Hill gas hydrate field, Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, Evan A.; Kastner, Miriam; Robertson, Gretchen; Jannasch, Hans; Weinstein, Yishai

    2005-07-01

    Four newly designed flux meters called the MOSQUITO (Multiple Orifice Sampler and Quantitative Injection Tracer Observer), capable of measuring fluid flow rates and sampling pore fluid chemistry simultaneously, and two temperature loggers were deployed for 430 days adjacent to the Bush Hill hydrate mound in the northern Gulf of Mexico (GC 185). The main objective of the deployment was to understand how chemistry, temperature, and subsurface hydrology dynamically influence the growth and dissociation of the gas hydrate mound. The flux meters were deployed in a mussel field, in bacterial mats, in a tubeworm field, and at a background site approximately 100 m southwest of the hydrate mound. Results from the longterm chemical monitoring suggest that this system is not in dynamic equilibrium. Gas hydrate actively formed within the mussel field adjacent to the most active gas vent, in the tubeworm field, and at the background site. The hydrology is variable with upward flow rates ranging from 1-90 cm/yr and downward flow rates from 3-130 cm/yr. Two distinct hydrologic pulsing events were sampled across the three mound sites, which advect a fluid from depth that further stabilizes the gas hydrate deposit. The hydrogeochemistry at Bush Hill seems to be influenced by multiple mechanisms such as active formation of gas hydrate, fluid influx and outflux due to active venting of CH4 at transient methane seeps at and near the mound, local salt tectonics, and density driven convection. The fluxes of fluid, solutes, and methane may have a significant impact on the seafloor biochemical environment and the water column chemistry at Bush Hill. (Author)

  12. Passive Q-switching in CW-CO2 laser with SF6 as an intracavity saturable absorber

    International Nuclear Information System (INIS)

    Al-Hawat, Sh.

    2007-10-01

    A passive Q-switching was applied to a tunable CW CO 2 laser with output power about 3.5 W using SF 6 as a saturable absorber inside the cavity. The Q-Switching phenomenon was studied ( pulse shape, pulse duration, repetition rate and conditions of its generation ) at the spectral lines of 10P(10), 10P(26), 10P(28) and 10P(30) from the branch of 10P of CO 2 laser. These lines had a weak absorption in relation to other lines of this branch, under SF 6 pressure till 0.5 mbar. To control the behaviour of such phenomenon, the gases He and Xe were added separately to SF 6 . It was observed that the Q-switching phenomenon was depended on the added gas pressure of Xe and He, through the repetitive rate of pulses , duration and energy of generated laser pulse. A computational program was written to calculate the Q-switching pulses parameters under similar conditions as those applied in the case of SF 6 +He mixture. A comparison was made with the experimental data , not so big discrepancies were observed between them. In addition to that, absorption coefficients of SF 6 were determined in two cases: the first one when the absorption cell was located outside the laser cavity, and the second one when the cell was located inside the cavity. On the basis of obtained coefficients the absorption cross sections of SF 6 were found and compared with NIST database.(author)

  13. First-principles study of SF_6 decomposed gas adsorbed on Au-decorated graphene

    International Nuclear Information System (INIS)

    Zhang, Xiaoxing; Yu, Lei; Gui, Yingang; Hu, Weihua

    2016-01-01

    Graphical abstract: - Highlights: • We theoretically investigated the decomposed gaseous components of sulfur hexafluoride (SF_6), namely, H_2S, SO_2, SOF_2, and SO_2F_2, adsorbed on pristine and Au-embedded graphene based on DFT-D, in which the van der Waals effect is considered. • H_2S, SO_2, SOF_2, and SO_2F_2 are chemisorption on Au-doped graphene, appreciably stronger than physisorption on pristine graphene in which the van der Waals dominates. • Only H_2S exhibits n-type doping to Au-graphene, whereas the rest gases exhibit p-type doping. The n-type and p-type sensing behaviors that Au-doped graphene displays to different gases play a crucial role in selective sensing application. • Magnetic moments fluctuate substantially in the original Au-graphene when H_2S and SO_2 are adsorbed. While the adsorption effects of SOF_2 and SO_2F_2 generate magnetism quenching. The different changes of magnetic moments in every adsorption system provide another approach to selective detection. • The charge transfer mechanism is deeply discussed in this paper. - Abstract: We theoretically investigated the decomposed gaseous components of sulfur hexafluoride (SF_6), namely, H_2S, SO_2, SOF_2, and SO_2F_2, adsorbed on pristine and Au-embedded graphene based on the revised Perdew–Burke–Ernzerhof calculation, which empirically includes a dispersion correction (DFT-D) for van der Waals interaction with standard generalized gradient approximation. Pristine graphene exhibits weak adsorption and absence of charge transfer, which indicates barely satisfactory sensing for decomposed components. The Au atom introduces magnetism to the pristine graphene after metal-embedded decoration as well as enhances conductivity. All four molecules induce certain hybridization between the molecules and Au-graphene, which results in chemical interactions. SOF_2 and SO_2F_2 exhibit a strong chemisorption interaction with Au-graphene, while H_2S and SO_2 exhibit quasi-molecular binding

  14. Analysis of the Sensitivity of K-Type Molecular Sieve-Deposited MWNTs for the Detection of SF6 Decomposition Gases under Partial Discharge

    Science.gov (United States)

    Zhang, Xiaoxing; Li, Xin; Luo, Chenchen; Dong, Xingchen; Zhou, Lei

    2015-01-01

    Sulfur hexafluoride (SF6) is widely utilized in gas-insulated switchgear (GIS). However, part of SF6 decomposes into different components under partial discharge (PD) conditions. Previous research has shown that the gas responses of intrinsic and 4 Å-type molecular sieve-deposited multi-wall carbon nanotubes (MWNTs) to SOF2 and SO2F2, two important decomposition components of SF6, are not obvious. In this study, a K-type molecular sieve-deposited MWNTs sensor was developed. Its gas response characteristics and the influence of the mixture ratios of gases on the gas-sensing properties were studied. The results showed that, for sensors with gas mixture ratios of 5:1, 10:1, and 20:1, the resistance change rate increased by nearly 13.0% after SOF2 adsorption, almost 10 times that of MWNTs sensors, while the sensors’ resistance change rate with a mixture ratio of 10:1 reached 17.3% after SO2F2 adsorption, nearly nine times that of intrinsic MWNT sensors. Besides, a good linear relationship was observed between concentration of decomposition components and the resistance change rate of sensors. PMID:26569245

  15. Analysis of the Sensitivity of K-Type Molecular Sieve-Deposited MWNTs for the Detection of SF6 Decomposition Gases under Partial Discharge

    Directory of Open Access Journals (Sweden)

    Xiaoxing Zhang

    2015-11-01

    Full Text Available Sulfur hexafluoride (SF6 is widely utilized in gas-insulated switchgear (GIS. However, part of SF6 decomposes into different components under partial discharge (PD conditions. Previous research has shown that the gas responses of intrinsic and 4 Å-type molecular sieve-deposited multi-wall carbon nanotubes (MWNTs to SOF2 and SO2F2, two important decomposition components of SF6, are not obvious. In this study, a K-type molecular sieve-deposited MWNTs sensor was developed. Its gas response characteristics and the influence of the mixture ratios of gases on the gas-sensing properties were studied. The results showed that, for sensors with gas mixture ratios of 5:1, 10:1, and 20:1, the resistance change rate increased by nearly 13.0% after SOF2 adsorption, almost 10 times that of MWNTs sensors, while the sensors’ resistance change rate with a mixture ratio of 10:1 reached 17.3% after SO2F2 adsorption, nearly nine times that of intrinsic MWNT sensors. Besides, a good linear relationship was observed between concentration of decomposition components and the resistance change rate of sensors.

  16. Analysis, simulation and control of electromagnetic transients in gas insulated substations in SF6 by means of grounding grid; Analisis, simulacion y control de transitorios electromagneticos en subestaciones aisladas en SF6 por medio de redes de tierra

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez Martinez, Gaston

    2007-12-15

    The use of SF6 substations is actually an extensive practice in industrial countries. Some of they replace conventional air substations and the others are new designs in the range of 34.5 kV to 1000 kV. During the switching events in a GIS substation, very fast transients overvoltage may appear and originate faults, malfunctions in the electronic and control equipment, besides the risk by electrical discharge in the personnel who are working in the substation. These overvoltage are produced by the collapse of the electric field on GIS terminals during switching events originating Very Fast Transient Overvoltage (VFTO) and the increase of the Transient Enclosure Voltage (TEV). This investigation is focused on diminishing the magnitude of the VFTO and TEV by designing and redesigning grounding grids for gas insulated substations in SF6. The objective of this work is to design a grounding grid for an air substation and redesign it for a GIS substation. The computer simulation uses a detailed model of the substation in SF6 interconnected with an aerial grounding grid and by adding methodologically grounding rods, the VFTO and TEV within the GIS are reduced. The results of the computer simulation show that the designed grounding grid allows considerably diminishing the magnitude of the VFTO; nevertheless this design doesn't appropriately attenuate the TEV magnitude. [Spanish] Hoy en dia, el uso de subestaciones GIS se ha generalizado. Algunas reemplazan a las subestaciones aereas y otras son de nueva creacion y se instalan en tensiones de 34.5kV hasta 1000 kV. Durante las operaciones de maniobra de la subestacion GIS, se presentan sobretensiones transitorias ultra rapidas que pueden dar origen a diversas fallas, a un malfuncionamiento del equipo electronico y de control asi como el riesgo por descarga electrica al personal que labora en la subestacion. Estas sobretensiones se producen debido al colapso del campo electrico en terminales del interruptor ante

  17. Metal-free reduction of the greenhouse gas sulfur hexafluoride, formation of SF5 containing ion pairs and the application in fluorinations

    KAUST Repository

    Rueping, Magnus

    2017-05-04

    A protocol for the fast and selective two-electron reduction of the potent greenhouse gas sulfur hexafluoride (SF6) by organic electron donors at ambient temperature has been developed. The reaction yields solid ion pairs consisting of donor dications and SF5-anions which can be effectively used in fluorination reactions.

  18. Study on SF6 trace experiment in Lianyungang Nuclear Power Plant

    International Nuclear Information System (INIS)

    Hu Erbang; Yan Jiangyu; Zhang Yongyi; Wen Lianzhong

    2001-01-01

    10 times SF 6 trace experiments were successfully performed in August 1997 on a very complex terrain of Lianyungang Nuclear Power Plant in order to obtain plume trajectory and diffusion parameters. SF 6 is released from the top of a tower of 100 m. The sample points are arranged not only on the sample lines but also on the areas near residences. About 50 samples are obtained in each SF 6 trace experiment. The samples of SF 6 are analysed by the GC-ECD method. The weather stability is 5 times C and D stabilities respectively if using P-G method or 10 times D stabilities if using ΔT-U method. A least-square method is adopted to obtain the diffusion parameters from diffusion equation. Meanwhile the effect on the diffusion parameters from sampling time is measured based on the above SF 6 trace experiment

  19. Gas-Filled Capillary Model

    International Nuclear Information System (INIS)

    Steinhauer, L. C.; Kimura, W. D.

    2006-01-01

    We have developed a 1-D, quasi-steady-state numerical model for a gas-filled capillary discharge that is designed to aid in selecting the optimum capillary radius in order to guide a laser beam with the required intensity through the capillary. The model also includes the option for an external solenoid B-field around the capillary, which increases the depth of the parabolic density channel in the capillary, thereby allowing for propagation of smaller laser beam waists. The model has been used to select the parameters for gas-filled capillaries to be utilized during the Staged Electron Laser Acceleration -- Laser Wakefield (STELLA-LW) experiment

  20. Ground-based FTIR retrievals of SF6 on Reunion Island

    Directory of Open Access Journals (Sweden)

    M. Zhou

    2018-02-01

    Full Text Available SF6 total columns were successfully retrieved from FTIR (Fourier transform infrared measurements (Saint Denis and Maïdo on Reunion Island (21° S, 55° E between 2004 and 2016 using the SFIT4 algorithm: the retrieval strategy and the error budget were presented. The FTIR SF6 retrieval has independent information in only one individual layer, covering the whole of the troposphere and the lower stratosphere. The trend in SF6 was analysed based on the FTIR-retrieved dry-air column-averaged mole fractions (XSF6 on Reunion Island, the in situ measurements at America Samoa (SMO and the collocated satellite measurements (Michelson Interferometer for Passive Atmospheric Sounding, MIPAS, and Atmospheric Chemistry Experiment Fourier Transform Spectrometer, ACE-FTS in the southern tropics. The SF6 annual growth rate from FTIR retrievals is 0.265 ± 0.013 pptv year−1 for 2004–2016, which is slightly weaker than that from the SMO in situ measurements (0.285 ± 0.002 pptv year−1 for the same time period. The SF6 trend in the troposphere from MIPAS and ACE-FTS observations is also close to the ones from the FTIR retrievals and the SMO in situ measurements.

  1. Ground-based FTIR retrievals of SF6 on Reunion Island

    Science.gov (United States)

    Zhou, Minqiang; Langerock, Bavo; Vigouroux, Corinne; Wang, Pucai; Hermans, Christian; Stiller, Gabriele; Walker, Kaley A.; Dutton, Geoff; Mahieu, Emmanuel; De Mazière, Martine

    2018-02-01

    SF6 total columns were successfully retrieved from FTIR (Fourier transform infrared) measurements (Saint Denis and Maïdo) on Reunion Island (21° S, 55° E) between 2004 and 2016 using the SFIT4 algorithm: the retrieval strategy and the error budget were presented. The FTIR SF6 retrieval has independent information in only one individual layer, covering the whole of the troposphere and the lower stratosphere. The trend in SF6 was analysed based on the FTIR-retrieved dry-air column-averaged mole fractions (XSF6) on Reunion Island, the in situ measurements at America Samoa (SMO) and the collocated satellite measurements (Michelson Interferometer for Passive Atmospheric Sounding, MIPAS, and Atmospheric Chemistry Experiment Fourier Transform Spectrometer, ACE-FTS) in the southern tropics. The SF6 annual growth rate from FTIR retrievals is 0.265 ± 0.013 pptv year-1 for 2004-2016, which is slightly weaker than that from the SMO in situ measurements (0.285 ± 0.002 pptv year-1) for the same time period. The SF6 trend in the troposphere from MIPAS and ACE-FTS observations is also close to the ones from the FTIR retrievals and the SMO in situ measurements.

  2. Arc modelling in SF6 circuit breakers

    International Nuclear Information System (INIS)

    Verite, J.C.; Boucher, T.; Comte, A.; Delalondre, C.; Robin-Jouan, P.; Serres, E.; Texier, V.; Barrault, M.; Chevrier, P.; Fievet, C.

    1995-06-01

    The paper presents the work done by an operator, EDF and two manufacturers to improve the physical models and numerical methods used to simulate the behavior of the plasma and cold gas around it in a breaking chamber of the HV SF6 circuit breaker, during the high-current phase. This work concerns flow phenomena, in particular incorporating compressibility and the study of turbulence, the coupling between these flow phenomena and electromagnetic phenomena, and finally, radiation - which plays an essential role in energy transfer during the high-current phase. For this latter aspect, emission but also absorption were proven to play a major role, and the two were introduced into the models. The paper presents the models developed and the results obtained with them for simulation of two circuit breaker mock-ups (a double-pressure circuit breaker mock-up and a self-expanding and rotating arc circuit breaker mock-up). (author)

  3. A single gas chromatograph for accurate atmospheric mixing ratio measurements of CO2, CH4, N2O, SF6 and CO

    Directory of Open Access Journals (Sweden)

    H. A. J. Meijer

    2009-09-01

    Full Text Available We present an adapted gas chromatograph capable of measuring simultaneously and semi-continuously the atmospheric mixing ratios of the greenhouse gases CO2, CH4, N2O and SF6 and the trace gas CO with high precision and long-term stability. The novelty of our design is that all species are measured with only one device, making it a very cost-efficient system. No time lags are introduced between the measured mixing ratios. The system is designed to operate fully autonomously which makes it ideal for measurements at remote and unmanned stations. Only a small amount of sample air is needed, which makes this system also highly suitable for flask air measurements. In principle, only two reference cylinders are needed for daily operation and only one calibration per year against international WMO standards is sufficient to obtain high measurement precision and accuracy. The system described in this paper is in use since May 2006 at our atmospheric measurement site Lutjewad near Groningen, The Netherlands at 6°21´ E, 53°24´N, 1 m a.s.l. Results show the long-term stability of the system. Observed measurement precisions at our remote research station Lutjewad were: ±0.04 ppm for CO2, ±0.8 ppb for CH4, ±0.8 ppb for CO, ±0.3 ppb for N2O, and ±0.1 ppt for SF6. The ambient mixing ratios of all measured species as observed at station Lutjewad for the period of May 2007 to August 2008 are presented as well.

  4. Improved gas mixtures for gas-filled particle detectors

    Science.gov (United States)

    Christophorou, L.G.; McCorkle, D.L.; Maxey, D.V.; Carter, J.G.

    Improved binary and tertiary gas mixture for gas-filled particle detectors are provided. The components are chosen on the basis of the principle that the first component is one gas or mixture of two gases having a large electron scattering cross section at energies of about 0.5 eV and higher, and the second component is a gas (Ar) having a very small cross section at and below about 0.5 eV; whereby fast electrons in the gaseous mixture are slowed into the energy range of about 0.5 eV where the cross section for the mixture is small and hence the electron mean free path is large. The reduction in both the cross section and the electron energy results in an increase in the drift velocity of the electrons in the gas mixtures over that for the separate components for a range of E/P (pressure-reduced electron field) values. Several gas mixtures are provided that provide faster response in gas-filled detectors for convenient E/P ranges as compared with conventional gas mixtures.

  5. Validation of the SF-6D Health State Utilities Measure in Lower Extremity Sarcoma

    Directory of Open Access Journals (Sweden)

    Kenneth R. Gundle

    2014-01-01

    Full Text Available Aim. Health state utilities measures are preference-weighted patient-reported outcome (PRO instruments that facilitate comparative effectiveness research. One such measure, the SF-6D, is generated from the Short Form 36 (SF-36. This report describes a psychometric evaluation of the SF-6D in a cross-sectional population of lower extremity sarcoma patients. Methods. Patients with lower extremity sarcoma from a prospective database who had completed the SF-36 and Toronto Extremity Salvage Score (TESS were eligible for inclusion. Computed SF-6D health states were given preference weights based on a prior valuation. The primary outcome was correlation between the SF-6D and TESS. Results. In 63 pairs of surveys in a lower extremity sarcoma population, the mean preference-weighted SF-6D score was 0.59 (95% CI 0.4–0.81. The distribution of SF-6D scores approximated a normal curve (skewness = 0.11. There was a positive correlation between the SF-6D and TESS (r=0.75, P<0.01. Respondents who reported walking aid use had lower SF-6D scores (0.53 versus 0.61, P=0.03. Five respondents underwent amputation, with lower SF-6D scores that approached significance (0.48 versus 0.6, P=0.06. Conclusions. The SF-6D health state utilities measure demonstrated convergent validity without evidence of ceiling or floor effects. The SF-6D is a health state utilities measure suitable for further research in sarcoma patients.

  6. The gas filled separator as a separation method to detect transuranic elements

    International Nuclear Information System (INIS)

    Ninov, V.

    1992-08-01

    The mass spectrometer NASE (NAchSEparator) built as a post-separator and located behind the velocity filter SHIP at the GSI in Darmstadt, was taken into operation as a gas-filled separator, and its separation properties for fusion products from heavy ion reactions were studied. Chapter 2 describes the principle of separation in a gas-filled magnet. The technical specifications of the separator, the detectors and the setup of detection electronics are outlined in chapter 3. The studies of separation properties are described in chapter 4, and chapter 5 deals with preliminary applications of the gas-filled separator to detect isotopes poor in neutrons, with an atomic number Z = 92, 93. Chapter 6 is concerned with preliminary tests to detect heavy nuclei with an atomic number Z > = 100 by means of light radiation and actinide targets. The experimental results of comparative measurements between the velocity filter SHIP and the gas-filled separator are pointed out in chapter 7, and future application possibilities of gas-filled separators for synthesis of heaviest nuclei through asymmetric reactions are discussed. (orig./BBR) [de

  7. Adsorption behaviour of SF6 decomposed species onto Pd4-decorated single-walled CNT: a DFT study

    Science.gov (United States)

    Cui, Hao; Zhang, Xiaoxing; Zhang, Jun; Tang, Ju

    2018-07-01

    Metal nanocluster decorated single-walled carbon nanotubes (SWCNT) with improved adsorption behaviour towards gaseous molecules compared with intrinsic ones, have been widely accepted as a workable media for gas interaction due to their strong catalysis. In this work, Pd4 cluster is determined as a catalytic centre to theoretically study the adsorption property of Pd4-decorated SWCNT upon SF6 decomposed species. Results indicate that Pd4-SWCNT possessing good responses and sensitivities towards three composed species of SF6 could realise selective detection for them according to the different conductivity changes resulting from the varying adsorption ability. The response of Pd4-SWCNT upon three molecules in order is SOF2 > H2S > SO2, and the conductivity of the proposed material is about to increase in SOF2 and H2S systems, while declining in SO2 system. Such conclusions would be helpful for experimentalists to explore novel SWCNT-based sensors in evaluating the operating state of SF6 insulation devices.

  8. Gas filled detectors

    International Nuclear Information System (INIS)

    Stephan, C.

    1993-01-01

    The main types of gas filled nuclear detectors: ionization chambers, proportional counters, parallel-plate avalanche counters (PPAC) and microstrip detectors are described. New devices are shown. A description of the processes involved in such detectors is also given. (K.A.) 123 refs.; 25 figs.; 3 tabs

  9. Unchained Melody: Revisiting the Estimation of SF-6D Values

    Science.gov (United States)

    Craig, Benjamin M.

    2015-01-01

    Purpose In the original SF-6D valuation study, the analytical design inherited conventions that detrimentally affected its ability to predict values on a quality-adjusted life year (QALY) scale. Our objective is to estimate UK values for SF-6D states using the original data and multi-attribute utility (MAU) regression after addressing its limitations and to compare the revised SF-6D and EQ-5D value predictions. Methods Using the unaltered data (611 respondents, 3503 SG responses), the parameters of the original MAU model were re-estimated under 3 alternative error specifications, known as the instant, episodic, and angular random utility models. Value predictions on a QALY scale were compared to EQ-5D3L predictions using the 1996 Health Survey for England. Results Contrary to the original results, the revised SF-6D value predictions range below 0 QALYs (i.e., worse than death) and agree largely with EQ-5D predictions after adjusting for scale. Although a QALY is defined as a year in optimal health, the SF-6D sets a higher standard for optimal health than the EQ-5D-3L; therefore, it has larger units on a QALY scale by construction (20.9% more). Conclusions Much of the debate in health valuation has focused on differences between preference elicitation tasks, sampling, and instruments. After correcting errant econometric practices and adjusting for differences in QALY scale between the EQ-5D and SF-6D values, the revised predictions demonstrate convergent validity, making them more suitable for UK economic evaluations compared to original estimates. PMID:26359242

  10. Gas-filled targets for large scalelength plasma interaction experiments on Nova

    International Nuclear Information System (INIS)

    Powers, L.V.; Berger, R.L.; Munro, D.H.

    1994-11-01

    Stimulated Brillouin backscatter from large scale length gas-filled targets has been measured on Nova. These targets were designed to approximate conditions in indirect drive ignition target designs in underdense plasma electron density (n e ∼10 21 /cm 3 ), temperature (T e >3 keV), and gradient scale lengths (L n ∼ mm, L v >6 mm) as well as calculated gain for stimulated Brillouin scattering (SBS). The targets used in these experiments were gas-filled balloons with polyimide walls (gasbags) and gas-filled hohlraums. Detailed characterization using x-ray imaging and x-ray and optical spectroscopy verifies that the calculated plasma conditions are achieved. Time-resolved SBS backscatter from these targets is <3% for conditions similar to ignition target designs

  11. Elimination of particle effects in SF/sub 6/ insulated transmission systems. First quarterly report

    Energy Technology Data Exchange (ETDEWEB)

    Dale, S.J.

    1979-01-01

    The purpose of this program is to develop methods and equipment to eliminate the adverse effect of particle contamination in SF/sub 6/-insulated transmission (CGIT) systems, so that the excellent dielectric properties of SF/sub 6/ can be fully exploited. Presently, CGIT systems are operated at about 10% of the dielectric strength capability of the SF/sub 6/ gas. The program includes theoretical and experimental evaluation of concepts, optimization and verification studies in CGIT systems, and reliability analysis, documentation of designs and economic analysis. Progress is now being made on evaluating alternative conductor and sheath designs to minimize the effect of particles. Materials for solid insulation is being investigated for the same purpose; the effort is presently concentrated on obtaining reliable quantitative measurement techniques of electrostatic properties. Computer calculation of particle trap configurations are being made to determine the optimum trap configurations. A novel particle trapping technique is being using adhesive materials. Manufacture and field control technique studies has commenced with a study of mechanical vibration techniques. An experimental test chamber consisting of a 9 m (30 foot) long 145 kV bus has been designed. This system will be used in testing of particle control concepts and in migration and optimization studies.

  12. Properties and etching rates of negative ions in inductively coupled plasmas and dc discharges produced in Ar/SF6

    International Nuclear Information System (INIS)

    Draghici, M.; Stamate, E.

    2010-01-01

    Negative ion production is investigated in a chamber with transversal magnetic filter operated in dc or inductively coupled plasma (ICP) modes in Ar/SF 6 gas mixtures. Plasma parameters are evaluated by mass spectrometry and Langmuir probe for different discharge conditions. The density ratio of negative ion to electron exceeded 300 in dc mode while it was below 100 in the ICP mode. The possibility to apply a large positive bias to an electrode without affecting the plasma potential and the transition from a negative sheath to anodic glow are also investigated. The etching rates by positive and negative ions are evaluated on silicon substrate for different Ar/SF 6 gas ratios. The etching rate by negative ions was with less than 5% smaller than that by positive ions.

  13. Properties and etching rates of negative ions in inductively coupled plasmas and dc discharges produced in Ar/SF6

    DEFF Research Database (Denmark)

    Draghici, Mihai; Stamate, Eugen

    2010-01-01

    of negative ion to electron exceeded 300 in dc mode while it was below 100 in the ICP mode. The possibility to apply a large positive bias to an electrode without affecting the plasma potential and the transition from a negative sheath to anodic glow are also investigated. The etching rates by positive...... and negative ions are evaluated on silicon substrate for different Ar/SF6 gas ratios. The etching rate by negative ions was with less than 5% smaller than that by positive ions.......Negative ion production is investigated in a chamber with transversal magnetic filter operated in dc or inductively coupled plasma (ICP) modes in Ar/SF6 gas mixtures. Plasma parameters are evaluated by mass spectrometry and Langmuir probe for different discharge conditions. The density ratio...

  14. Effects of SF$_{6}$ on the avalanche mode operation of a real-sized double-gap resistive plate chamber for the Compact Muon Solenoid experiment

    CERN Document Server

    Ahn Sung Hwan; Hong, B; Hong, S J; Ito, M; Kim, B I; Kim, J H; Kim, Y J; Kim, Y U; Koo, D G; Lee, H W; Lee, K B; Lee, K S; Lee, S J; Lim, J K; Moon, D H; Nam, S K; Park, S; Park, W J; Rhee, J T; Ryu, M S; Shim, H H; Sim, K S; Kang, T I

    2005-01-01

    We present the design and the test, results for a real-sized prototype resistive plate chamber by using cosmic-ray muons for the forward region of the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC). In particular, we investigate the effects of adding SF/sub 6/ to the gas mixture for the avalanche mode operation of a resistive plate chamber. A small fraction of SF/sub 6/ is very effective in suppressing streamer signals in a resistive plate chamber. The shapes of the muon detection efficiency and the muon cluster size remain similar, but are shifted to higher operating voltage by SF/sub 6/. The noise cluster rate and size are not influenced by SF/sub 6/.

  15. Relaxation effects in ionic mobility and cluster formation: negative ions in SF6 at high pressures

    International Nuclear Information System (INIS)

    Juarez, A M; De Urquijo, J; Hinojosa, G; Hernandez-Avila, J L; Basurto, E

    2010-01-01

    The relaxation effects of the ionic mobility and the formation of negative-ion clusters in SF 6 are studied in this work. For this purpose, we have measured the mobility of negative ions in SF 6 over the pressure range 100-800 Torr at a fixed value of density-normalized electric field, E/N, of 20 Td (1 Townsend = 10 -17 V cm 2 ). The data obtained show a clear dependence of the negative-ion drift velocity on drift distance. It is observed that the drift velocity (mobility) reaches a steady-state value only for drift distances above 2 cm, over the studied pressure range. In addition to this, we have observed that the ionic mobility depends strongly on the gas pressure. An explanation of this dependence of the ionic mobility on gas pressure is given in terms of a negative-ion clustering formation process. It was found that the assumption of a linear dependence of the cluster ion mass on pressure provides a satisfactory explanation for the observed mobilities.

  16. An Improved SF6 System for the FXR Induction Linac Blumlein Switches

    International Nuclear Information System (INIS)

    DeHope, W; Kihara, R; Griffin, K L; Ong, M; Ross, T

    2007-01-01

    The now-mature FXR (Flash X-Ray) radiographic facility at Lawrence Livermore National Laboratory will be briefly described with emphasis on its pulsed power system. The heart of each accelerating cell's pulse forming Blumlein is it's sulfur hexafluoride-based triggered closing switch. FXR's recent upgrade to a recirculating SF 6 gas reclamation system will be described and the resulting accelerator performance and reliability improvements documented. This was accompanied by a detailed switch breakdown study on FXR's Test Stand and the recent analysis of the resulting statistics will be shown

  17. A comparison between spectra of runaway electron beams in SF6 and air

    International Nuclear Information System (INIS)

    Zhang, Cheng; Wang, Ruexue; Yan, Ping; Shao, Tao; Tarasenko, Victor; Gu, Jianwei; Baksht, Evgenii

    2015-01-01

    Runaway electron (RAE) with extremely high-energy plays important role on the avalanche propagation, streamer formation, and ionization waves in nanosecond-pulse discharges. In this paper, the generation of a supershort avalanche electron beam (SAEB) in SF 6 and air in an inhomogeneous electric field is investigated. A VPG-30-200 generator with a pulse rise time of ∼1.6 ns and a full width at half maximum of 3–5 ns is used to produce RAE beams. The SAEBs in SF 6 and air are measured by using aluminum foils with different thicknesses. Furthermore, the SAEB spectra in SF 6 and air at pressures of 7.5 Torr, 75 Torr, and 750 Torr are compared. The results showed that amplitude of RAE beam current generated at the breakdown in SF 6 was approximately an order of magnitude less than that in air. The energy of SAEB in air was not smaller than that in SF 6 in nanosecond-pulse discharges under otherwise equal conditions. Moreover, the difference between the maximum energy of the electron distributions in air and SF 6 decreased when the rise time of the voltage pulse increased. It was because the difference between the breakdown voltages in air and SF 6 decreased when the rise time of the voltage pulse increased

  18. A comparison between spectra of runaway electron beams in SF6 and air

    Science.gov (United States)

    Zhang, Cheng; Tarasenko, Victor; Gu, Jianwei; Baksht, Evgenii; Wang, Ruexue; Yan, Ping; Shao, Tao

    2015-12-01

    Runaway electron (RAE) with extremely high-energy plays important role on the avalanche propagation, streamer formation, and ionization waves in nanosecond-pulse discharges. In this paper, the generation of a supershort avalanche electron beam (SAEB) in SF6 and air in an inhomogeneous electric field is investigated. A VPG-30-200 generator with a pulse rise time of ˜1.6 ns and a full width at half maximum of 3-5 ns is used to produce RAE beams. The SAEBs in SF6 and air are measured by using aluminum foils with different thicknesses. Furthermore, the SAEB spectra in SF6 and air at pressures of 7.5 Torr, 75 Torr, and 750 Torr are compared. The results showed that amplitude of RAE beam current generated at the breakdown in SF6 was approximately an order of magnitude less than that in air. The energy of SAEB in air was not smaller than that in SF6 in nanosecond-pulse discharges under otherwise equal conditions. Moreover, the difference between the maximum energy of the electron distributions in air and SF6 decreased when the rise time of the voltage pulse increased. It was because the difference between the breakdown voltages in air and SF6 decreased when the rise time of the voltage pulse increased.

  19. Ion and electron swarm studies of relevance to plasma processing: positive ion-molecule and electron-molecule studies of SF6 and derivatives

    International Nuclear Information System (INIS)

    Atterbury, C.; Kennedy, R.A.; Critchley, A.D.J.; Mayhew, C.A.

    2002-01-01

    dissociative charge transfer and various abstraction channels. Non-dissociative charge transfer is not observed, implying that the parent ion dissociates rapidly to the fragment ion and associated neutral(s). Figure 1 illustrated the reaction pathways accessible to the reagent ions either by dissociative charge transfer (simple fragmentation) and those involving migration of an F atom across the S-C bond. Electron attachment studies. Electron attachment rate coefficients and anion product branching ratios have been measured for electron attachment to XF 6 (X = S, Se and Te) and SF 5 X (X = Cl and CF 3 ), using an atmospheric pressure drift tube apparatus connected to a mass spectrometer. Results from these studies are presented. Electron attachment to XF 6 was observed to produce XF 6 + XF 5 + . When extrapolated to zero attaching gas concentration, the branching ratios are found to be similar, with XF 6 + dominate in each case. Despite this similarity, the electron attachment rate coefficients are found to be markedly different: k(SeF 6 ) ∼ 10 -2 x k(SF 6 ); k(TeF 6 ) ∼ 10 -3 x k(SF 6 ). SF 5 CF 3 and SF 5 Cl are also found to attach electrons at much slower rate than SF 6 . (author)

  20. Anisotropic etching of silicon for application in micro machine using plasma of SF6/CH4/O2/Ar and SF6/CF4/O2/Ar

    International Nuclear Information System (INIS)

    Reyes B, C.; Moshkalyov, S.A.; Swart, J.W.

    2004-01-01

    We investigated the reactive ion etching of silicon using SF 6 /CH 4 (CF 4 )/O 2 /Ar gas mixtures containing fluorine for MEMS applications. Etch rates and anisotropy of etch profiles were examined as a function of gas composition, material of electrode, and RF power. Etch depths were measured using a profilometers, and etch profiles were analyzed by scanning electron microscope. As a mask material, an aluminium film deposited by evaporation, was used. High anisotropy of etching of 0.95 was achieved at etch depths up to 20-30 micrometers and etch rates of approximately 0.3-0.6 μm/min. Highly anisotropic etching is based on a mechanism that enhance the ion bombarding and protects the sidewalls due to polymerization and/or oxidation mechanisms in order to avoid the lateral etch. However, under the anisotropic etching conditions, considerable damages of the etched surfaces (roughness formation), were observed. After etching experiments, wet / dry cleaning procedures were applied to remove surface residues resulting from the reactive ion etching and to improve the etched surface morphology. (Author)

  1. Arc modelling in SF{sub 6} circuit breakers

    Energy Technology Data Exchange (ETDEWEB)

    Verite, J.C. [Electricite de France, Clamart (France). Derection des Etudes et Recherches; Boucher, T.; Comte, A. [Electricite de France, Moret sur Loing (France). Direction des Etudes et Recherches; Delalondre, C. [Electricite de France, Chatou (France). Direction des Etudes et Recherches; Robin-Jouan, P.; Serres, E.; Texier, V. [GEC Alsthom, Villeurbanne (France). Direction Technique Haute et Moyenne Tension; Barrault, M.; Chevrier, P.; Fievet, C. [CEA Centre d`Etudes Nucleaires de Grenoble, 38 (France). Merlin Gerin

    1995-06-01

    The paper presents the work done by an operator, EDF and two manufacturers to improve the physical models and numerical methods used to simulate the behavior of the plasma and cold gas around it in a breaking chamber of the HV SF6 circuit breaker, during the high-current phase. This work concerns flow phenomena, in particular incorporating compressibility and the study of turbulence, the coupling between these flow phenomena and electromagnetic phenomena, and finally, radiation - which plays an essential role in energy transfer during the high-current phase. For this latter aspect, emission but also absorption were proven to play a major role, and the two were introduced into the models. The paper presents the models developed and the results obtained with them for simulation of two circuit breaker mock-ups (a double-pressure circuit breaker mock-up and a self-expanding and rotating arc circuit breaker mock-up). (author) 10 refs.

  2. Photodegradation of SF6 on polyisoprene surface: Implication on elimination of toxic byproducts

    International Nuclear Information System (INIS)

    Song Xiaoxiao; Liu Xingang; Ye Zhaolian; He Jincong; Zhang Renxi; Hou, Huiqi

    2009-01-01

    Photodegradation of SF 6 was performed on the surface of polyisoprene (PI) based on a brand new mechanism of 'controlled release of radicals'. Effective decomposition of SF 6 (60% of SF 6 was degraded in 4 h) was achieved due to the highly reductive radicals (mainly allylic radicals and excited C=C bond) which were generated from the photolysis of PI. No toxic fluoride was detected by FT-IR. The PI irradiated for 200 h in SF 6 circumstance was examined by XPS to be doped with fluorine and sulfur. Fouling due to photoinitiated polymerization on UV lamp was avoided because the radicals were released slowly. Photolysis of SF 6 in pure argon with the presence of irradiated PI showed kinetics of pseudo-first-order reaction and the degradation rate constant was 5.16 x 10 -5 s -1 . Factors which may affect the photolysis process such as introduction of O 2 and H 2 O were also examined.

  3. Design status and procurement activities of the High Voltage Deck 1 and Bushing for the ITER Neutral Beam Injector

    International Nuclear Information System (INIS)

    Boldrin, Marco; De Lorenzi, Antonio; Decamps, Hans; Grando, Luca; Simon, Muriel; Toigo, Vanni

    2013-01-01

    Highlights: ► ITER Neutral Beam Injector includes several non-standard components. ► The design status of the −1 MV dc HVD1 and Bushing is described. ► The paper reports also on the integrated layout of the two components. ► Preliminary electrostatic and thermal analyses are presented. ► Procurement activities are outlined. -- Abstract: The ITER Neutral Beam Injector (NBI) power supply system includes several non-standard components, whose ratings go beyond the present industrial practice. Two of these items, to be procured by Fusion for Energy, are: 1.A −1 MV dc air-insulated Faraday cage, called High Voltage Deck 1 (HVD1), hosting the Ion Source and Extractor Power Supplies (ISEPS) and the associated diagnostics. 2.A −1 MV dc feedthrough, called HVD1-TL Bushing, aimed at connecting the HVD1 to the gas (SF 6 ) insulated Transmission Line (TL), containing inside its High Voltage (HV) conductor all ISEPS power and control cables coming from the HVD1 to be connected to the NBI Ion Source services. The paper deals with the status of the design of the HVD1 and HVD1-TL Bushing, focusing on insulation, mechanical and thermal issues as well as on their integration with the other components of the power supply system. In particular, the insulation issue of the integrated system has been addressed by means of an electrostatic Finite Element (FE) analysis whilst a FE thermal simulation has been carried out to assess the impact of the dissipation of the proposed design of the inner conductors (ISEPS conductors) not actively cooled. Finally, the paper describes the status of procurement strategy and execution

  4. First-principles study of SF{sub 6} decomposed gas adsorbed on Au-decorated graphene

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaoxing, E-mail: xiaoxing.zhang@outlook.com [State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing University, Chongqing 400044 (China); Yu, Lei; Gui, Yingang [State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing University, Chongqing 400044 (China); Hu, Weihua [Institute for Clean Energy & Advanced Materials, Southwest University, Chongqing 400715 (China)

    2016-03-30

    Graphical abstract: - Highlights: • We theoretically investigated the decomposed gaseous components of sulfur hexafluoride (SF{sub 6}), namely, H{sub 2}S, SO{sub 2}, SOF{sub 2}, and SO{sub 2}F{sub 2}, adsorbed on pristine and Au-embedded graphene based on DFT-D, in which the van der Waals effect is considered. • H{sub 2}S, SO{sub 2}, SOF{sub 2}, and SO{sub 2}F{sub 2} are chemisorption on Au-doped graphene, appreciably stronger than physisorption on pristine graphene in which the van der Waals dominates. • Only H{sub 2}S exhibits n-type doping to Au-graphene, whereas the rest gases exhibit p-type doping. The n-type and p-type sensing behaviors that Au-doped graphene displays to different gases play a crucial role in selective sensing application. • Magnetic moments fluctuate substantially in the original Au-graphene when H{sub 2}S and SO{sub 2} are adsorbed. While the adsorption effects of SOF{sub 2} and SO{sub 2}F{sub 2} generate magnetism quenching. The different changes of magnetic moments in every adsorption system provide another approach to selective detection. • The charge transfer mechanism is deeply discussed in this paper. - Abstract: We theoretically investigated the decomposed gaseous components of sulfur hexafluoride (SF{sub 6}), namely, H{sub 2}S, SO{sub 2}, SOF{sub 2}, and SO{sub 2}F{sub 2}, adsorbed on pristine and Au-embedded graphene based on the revised Perdew–Burke–Ernzerhof calculation, which empirically includes a dispersion correction (DFT-D) for van der Waals interaction with standard generalized gradient approximation. Pristine graphene exhibits weak adsorption and absence of charge transfer, which indicates barely satisfactory sensing for decomposed components. The Au atom introduces magnetism to the pristine graphene after metal-embedded decoration as well as enhances conductivity. All four molecules induce certain hybridization between the molecules and Au-graphene, which results in chemical interactions. SOF{sub 2} and SO

  5. A comparison between spectra of runaway electron beams in SF{sub 6} and air

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Cheng; Wang, Ruexue; Yan, Ping; Shao, Tao, E-mail: st@mail.iee.ac.cn [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Key Laboratory of Power Electronics and Electric Drive, Chinese Academy of Sciences, Beijing 100190 (China); Tarasenko, Victor [Institute of High Current Electronics, 2/3 Akademichesky Ave., Tomsk 634055 (Russian Federation); National Research Tomsk State University, 36 Lenin Ave., Tomsk 634050 (Russian Federation); Gu, Jianwei [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Baksht, Evgenii [Institute of High Current Electronics, 2/3 Akademichesky Ave., Tomsk 634055 (Russian Federation)

    2015-12-15

    Runaway electron (RAE) with extremely high-energy plays important role on the avalanche propagation, streamer formation, and ionization waves in nanosecond-pulse discharges. In this paper, the generation of a supershort avalanche electron beam (SAEB) in SF{sub 6} and air in an inhomogeneous electric field is investigated. A VPG-30-200 generator with a pulse rise time of ∼1.6 ns and a full width at half maximum of 3–5 ns is used to produce RAE beams. The SAEBs in SF{sub 6} and air are measured by using aluminum foils with different thicknesses. Furthermore, the SAEB spectra in SF{sub 6} and air at pressures of 7.5 Torr, 75 Torr, and 750 Torr are compared. The results showed that amplitude of RAE beam current generated at the breakdown in SF{sub 6} was approximately an order of magnitude less than that in air. The energy of SAEB in air was not smaller than that in SF{sub 6} in nanosecond-pulse discharges under otherwise equal conditions. Moreover, the difference between the maximum energy of the electron distributions in air and SF{sub 6} decreased when the rise time of the voltage pulse increased. It was because the difference between the breakdown voltages in air and SF{sub 6} decreased when the rise time of the voltage pulse increased.

  6. Synthesis of Graphene-Based Sensors and Application on Detecting SF6 Decomposing Products: A Review

    Directory of Open Access Journals (Sweden)

    Xiaoxing Zhang

    2017-02-01

    Full Text Available Graphene-based materials have aroused enormous focus on a wide range of engineering fields because of their unique structure. One of the most promising applications is gas adsorption and sensing. In electrical engineering, graphene-based sensors are also employed as detecting devices to estimate the operation status of gas insulated switchgear (GIS. This paper reviews the main synthesis methods of graphene, gas adsorption, and sensing mechanism of its based sensors, as well as their applications in detecting SF6 decomposing products, such as SO2, H2S, SO2F2, and SOF2, in GIS. Both theoretical and experimental researches on gas response of graphene-based sensors to these typical gases are summarized. Finally, the future research trend about graphene synthesis technique and relevant perspective are also given.

  7. Development of ceramic roller bush for diesel fuel injection pump; Nenryo funsha pump yo ceramics sei roller bush no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Noda, K; Kamiya, S; Fujimura, M; Tsuzuki, M [Toyota Motor Corp., Aichi (Japan); Taniguchi, K [Denso Corp., Aichi (Japan)

    1997-10-01

    Silicon nitride ceramics have been applied to roller bush for diesel fuel injection pump in order to improve the seizure resistance. It was found that ceramic roller bush made it possible to improve the seizure load by more than three times as compared to conventional metal roller bush when the kerosene was used as lubricant The ceramic roller bush proved to be durable under engine operating conditions. 6 refs., 13 figs., 1 tab.

  8. Metal-free reduction of the greenhouse gas sulfur hexafluoride, formation of SF5 containing ion pairs and the application in fluorinations

    KAUST Repository

    Rueping, Magnus; Nikolaienko, Pavlo; Lebedev, Yury; Adams, Alina

    2017-01-01

    A protocol for the fast and selective two-electron reduction of the potent greenhouse gas sulfur hexafluoride (SF6) by organic electron donors at ambient temperature has been developed. The reaction yields solid ion pairs consisting of donor

  9. Construct validity of SF-6D health state utility values in an employed population.

    Science.gov (United States)

    Baxter, Siyan; Sanderson, Kristy; Venn, Alison; Otahal, Petr; Palmer, Andrew J

    2015-04-01

    Health utility values permit cost utility analysis in workplace health promotion; however, utility measures of working populations have not been validated. To investigate construct validity of SF-6D health utility in a public service workforce. SF-12v2 Health Survey was administered to 3,408 randomly selected public service employees in Australia in 2010. SF-12 scores were converted to SF-6D health utility values. Associations and correlates of SF-6D with health, socio-demographic and work characteristics [comorbidities, body mass index (BMI), Kessler-10 psychological distress (K10), education, salary, effort-reward imbalance (ERI), absenteeism] were explored. Ceiling effects were analysed. Nationally representative employee SF-6D values from the Household, Income and Labour Dynamics in Australia (HILDA) survey (n = 11,234) were compared. All analyses were stratified by sex. Mean (SE) age was 45.7 (0.35) males; 44.5 (0.22) females. Females represented 72 % of the sample. Mean (SE) health utility 0.792 (0.004); 0.771 (0.003) was higher in males. SF-6D demonstrated both a significant inverse association (p negative correlations (female; male) with K10 (r = -0.63; r = -0.66), comorbidity count (r = -0.40; r = -0.33), ERI (r = -0.37; r = -0.34) and absenteeism (p imbalance and absenteeism are negatively associated with employee health. SF-6D is a valid measure of perceived health states in working populations.

  10. SF6 laser remote sensing by CO2 laser DIAL lidar

    International Nuclear Information System (INIS)

    Parvin, P.; Basam, Z.; Zamanipour, Z.; Kariminezhad, H.; Boyook, N.; Borna, F.; Azari, T.; Eshragi, N.; Ataran, A.; Ghods Ahmad Zadeh, R.

    2004-01-01

    A DIAL system using tunable CO 2 laser has been demonstrated practically for remote sensing of SF 6 components in Mashad Shahid Motahhari Research Complex. Non toxic components of SF 6 as a rare isotope is studied to calibrate the lidar function in several conditions. The whole system enables us to detect ppm amounts of chemical gases as well as pollutants and poisonous species

  11. Ozone depleting substances and greenhouse gases HFCs, PFCs and SF{sub 6} consumption and emissions; Ozonlagsnedbrydende stoffer og drivhusgasserne HFC'er, PFC'er og SF{sub 6}. Forbrug og emissioner 2002

    Energy Technology Data Exchange (ETDEWEB)

    Sander Poulsen, T. [Planmiljoe, Veksoe Sjaelland (Denmark)

    2004-07-01

    The aim of the project is to map the 2002 Danish consumption of produced ozone depleting substances and the consumption and actual emission of the greenhouse gases HFCs, PFCs and SF{sub 6}. The inventory is performed, partly according to the guidelines recommended by IPCC (Intergovernmental Panel on Climate Change), and partly according to the method that has been used for previous mappings. The mapping is done partly in order to meet Denmark's international commitments to report and partly in order to monitor how the consumption of ozone depleting substances and the emissions of greenhouse gases develop. The mapping of ozone depleting substances includes the net consumption, meaning the amount of the imported raw materials in bulk or in drums minus any re-export of the substances in the form of raw materials. Mapping of the actual emissions of HFCs, PFCs and SF{sub 6} is done in continuation of previous greenhouse gas inventories. The inventory process is continuously improving due to development of international approved guidelines (IPCC) and the production of increasingly detailed data. (BA)

  12. Dynamics of infrared multiphonon dissociation of SF6 by molecular beam method

    International Nuclear Information System (INIS)

    Grant, E.R.; Coggiola, M.J.; Lee, Y.T.; Schulz, P.A.; Shen, Y.R.

    1977-01-01

    A crossed molecular beam apparatus has been adapted to study the dynamics of excitation and dissociation of polyatomic molecules in intense IR laser fields. Initial experiments have involved the study of the dissociation of SF 6 by CO 2 laser radiation at 10.6 μm. A molecular beam of SF 6 was formed by supersonic expansion using three stages of differential pumping. A grating tuned pulsed CO 2 TEA laser was used as the excitation source. The laser beam was focused by a 25 cm focal length ZnSe lens, and crossed the molecular beam near its focal point. The fragments produced by multiphonon dissociation of SF 6 within the small interaction region were detected as a function of recoil angle and velocity. (Auth.)

  13. Measurement of the electron attachment rates for SF6 and C7F14 at Te=0.2 eV in a magnetized Q machine plasma

    International Nuclear Information System (INIS)

    Merlino, Robert L.; Kim, Su-Hyun

    2008-01-01

    Electron attachment rates for SF 6 and C 7 F 14 were measured in a magnetized Q machine plasma at an electron temperature of 0.2±0.02 eV and with neutral gas pressures of P∼10 -4 Torr. The rate constants for attachment to SF 6 and C 7 F 14 were (7.6±2.0)x10 -8 and (2.2±0.9)x10 -7 cm 3 s -1 , respectively.

  14. SF6 gas insulated power substations. Effects of fast transients (VFT) on the equipment and adjacent equipment of the Itaipu Binacional SF6 insulated power substations; Subestaciones aisladas a gas SF6. Efectos de los transitorios rapidos (VFT's) sobre equipos y equipos adyacentes de las SE's SF6 de Itaipu Binacional

    Energy Technology Data Exchange (ETDEWEB)

    Santacruz Martinez, Miguel [Usina Hidroelectrica de Itaipu, Assuncao (Paraguay)]. E-mail: santcruz@itaipu.gov.py

    2001-07-01

    With the operation starting of the S F6 gas substations in high voltage systems occurs a new form of overvoltage presently known as Very Fast Transients. This paper aims the phenomenon characterization, defining the origins and the behaviour of the electric systems, and briefly presents the damages caused by the phenomenon on the equipment and adjacent equipment of S F6 gas insulated substations of the Itaipu Binacional, mainly on the power transformers and oil/S F6 isolators of the step-up transformers. These equipment was modified or are been modified as a consequence of the this overvoltage effects.

  15. Design status and procurement activities of the High Voltage Deck 1 and Bushing for the ITER Neutral Beam Injector

    Energy Technology Data Exchange (ETDEWEB)

    Boldrin, Marco, E-mail: marco.boldrin@igi.cnr.it [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy); De Lorenzi, Antonio [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy); Decamps, Hans [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Grando, Luca [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy); Simon, Muriel [Fusion For Energy, c/ Josep Pla 2, 08019 Barcelona (Spain); Toigo, Vanni [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy)

    2013-10-15

    Highlights: ► ITER Neutral Beam Injector includes several non-standard components. ► The design status of the −1 MV{sub dc} HVD1 and Bushing is described. ► The paper reports also on the integrated layout of the two components. ► Preliminary electrostatic and thermal analyses are presented. ► Procurement activities are outlined. -- Abstract: The ITER Neutral Beam Injector (NBI) power supply system includes several non-standard components, whose ratings go beyond the present industrial practice. Two of these items, to be procured by Fusion for Energy, are: 1.A −1 MV{sub dc} air-insulated Faraday cage, called High Voltage Deck 1 (HVD1), hosting the Ion Source and Extractor Power Supplies (ISEPS) and the associated diagnostics. 2.A −1 MV{sub dc} feedthrough, called HVD1-TL Bushing, aimed at connecting the HVD1 to the gas (SF{sub 6}) insulated Transmission Line (TL), containing inside its High Voltage (HV) conductor all ISEPS power and control cables coming from the HVD1 to be connected to the NBI Ion Source services. The paper deals with the status of the design of the HVD1 and HVD1-TL Bushing, focusing on insulation, mechanical and thermal issues as well as on their integration with the other components of the power supply system. In particular, the insulation issue of the integrated system has been addressed by means of an electrostatic Finite Element (FE) analysis whilst a FE thermal simulation has been carried out to assess the impact of the dissipation of the proposed design of the inner conductors (ISEPS conductors) not actively cooled. Finally, the paper describes the status of procurement strategy and execution.

  16. Development of high pressure-high vacuum-high conductance piston valve for gas-filled radiation detectors

    International Nuclear Information System (INIS)

    Prasad, D N; Ayyappan, R; Kamble, L P; Singh, J P; Muralikrishna, L V; Alex, M; Balagi, V; Mukhopadhyay, P K

    2008-01-01

    Gas-filled radiation detectors need gas filling at pressures that range from few cms of mercury to as high as 25kg/cm 2 at room temperature. Before gas-filling these detectors require evacuation to a vacuum of the order of ∼1 x 10 -5 mbar. For these operations of evacuation and gas filling a system consisting of a vacuum pump with a high vacuum gauge, gas cylinder with a pressure gauge and a valve is used. The valve has to meet the three requirements of compatibility with high-pressure and high vacuum and high conductance. A piston valve suitable for the evacuation and gas filling of radiation detectors has been designed and fabricated to meet the above requirements. The stainless steel body (80mmx160mm overall dimensions) valve with a piston arrangement has a 1/2 inch inlet/outlet opening, neoprene/viton O-ring at piston face and diameter for sealing and a knob for opening and closing the valve. The piston movement mechanism is designed to have minimum wear of sealing O-rings. The valve has been hydrostatic pressure tested up to 75bars and has Helium leak rate of less than 9.6x10 -9 m bar ltr/sec in vacuum mode and 2x10 -7 mbar ltr/sec in pressure mode. As compared to a commercial diaphragm valve, which needed 3 hours to evacuate a 7 litre chamber to 2.5x10 -5 mbar, the new valve achieved vacuum 7.4x10 -6 mbar in the same time under the same conditions

  17. Mechanism for negative corona current pulse in CO sub 2 -SF sub 6 mixtures

    CERN Document Server

    Zahoranova, A; Simor, M; Cernak, M

    2003-01-01

    Current waveforms of first negative corona pulses have been measured in CO sub 2 -SF sub 6 mixtures over a pressure range extending from 6.65 to 50 kPa and various overvoltages. Effects of changing cathode secondary electron emission were studied using a copper cathode coated by CuI and graphite. For a given set of experimental conditions it is concluded that in the mixtures containing up to 30% of SF sub 6 the negative corona pulse is associated with the formation of a cathode-directed streamer-like ionizing wave in the immediate vicinity of the cathode. This is in contrast to the discharge behaviour in air-SF sub 6 and N sub 2 -SF sub 6 mixtures, where in similar conditions the discharge develops according to a multi-avalanche Townsend mechanism. (rapid communication)

  18. Development of a selective thin film and of a hermetically sealed flat plate solar collector with gas filling

    Science.gov (United States)

    Zernial, W.

    1982-12-01

    The industrial productibility of a selective absorbing thin film was investigated on the basis of reactive cathodic sputtering of Ni. On substrates of 1.8 sq m of Al, Cu, steel and stainless steel, solar absorption values up to 97% were achieved at emissivities of 5 to 10%. A prototype flat plate collector for high temperatures with two covers and hermetical sealing was developed. The technical data of the collector were measured, dependent on the selectivity of the absorber, gas fillings of dry air, argon or SF6 and the geometry and were compared with those of an evacuated flat plate collector. A hermetical sealed double flat plate collector for low temperatures was developed which has the advantage of lower no load temperatures and higher energy gain for heating swimming pool water compared with a conventional flat plate collector. The insolation values on collectors were measured and were used for a calculation of the energy gains of different collector types.

  19. Flammability of Gas-Filled Polymers

    Directory of Open Access Journals (Sweden)

    Ushkov Valentin Anatol'evich

    2017-09-01

    Full Text Available The regularities of flame propagation on the horizontal surface of gas-filled polymers are considered depending on the concentration of oxygen in the oxidizer flow. The values of the coefficients in the expression describing relationship between the rate of flame propagation on the surface of foams and oxygen concentration are obtained. It was shown that with the mass content of reactive organophosphorus compounds reaching 4.0...5.9%, non-smoldering resole foam plastics with high performance characteristics are obtained. It was found that in order to obtain moderately combustible polyurethane foams based on oxyethylated phosphorus-containing polyols, the phosphorus concentration should not exceed 3 % of mass. To obtain flame-retardant urea-formaldehyde foam cellular plastics, the concentration of phosphorus should not exceed 0.3 % of mass. Physical-mechanical properties and flammability indices of developed gas-filled polymers based on reactive oligomers are presented.

  20. Identification of a novel ga-related bush mutant in pumpkin (cucurbita moschata duchesne)

    International Nuclear Information System (INIS)

    Wu, T.; Cao, J.

    2015-01-01

    Pumpkin (Cucurbita moschata Duchesne) bush mutant plants were characterized by short stems. The sensitivity of pumpkin bush mutant plants to exogenous hormones was identified in this study. Results revealed that internode elongation of bush mutant plants could respond to gibberellins (GA4+7 and GA3), but not to indole acetic acid (IAA) and brassinosteroids (BR); by contrast, the mutant phenotype of bush mutant plants could not be fully rescued by GA4+7 and GA3. The internode of bush mutant plants yielded a lower KS expression level than that of vine plants. Therefore, pumpkin bush mutant plants were designated as GA-related mutant plants eliciting a partial response to GAs; the action of IAA and BR might not be involved in the internode growth of pumpkin bush mutant plants, specifically Cucurbita moschata Duch. (author)

  1. Influence of the meteorological parameters on CFCs and SF6 concentration in the air of Krakow, Poland

    Science.gov (United States)

    Bielewski, Jarosław; Najman, Joanna; Śliwka, Ireneusz; Bartyzel, Jakub; Rosiek, Janusz

    2013-04-01

    key words: gas chromatography, trace gases, CFCs and SF6 measurements in urban area. Halogenated compounds (chlorofluorocarbons-CFCs), both natural and industrial, so-called freons, currently exist as trace gases in the entire human environment. The CFCs cause ozone depletion in the stratosphere. Moreover CFCs and SF6 take part in intensification of the greenhouse effect. The decisions of the Vienna Convention (1985) and of the Montreal Protocol (1987) limited the world production level of CFCs in the year 1989 at least 35% after 2004, 90% after 2015 and total reduction after year 2030. On account of international agreements, the measurements of CFCs and SF6 in air were started. Measurement "clean" stations were situated at places outside of urban areas influence and gathered on world program - AGAGE (Advanced Global Atmospheric Gases Experiment). One of these stations is Mace Head (Ireland, 53o N, 10o W), which participates in AGAGE since 1987 [1] and in European InGOS (Integrated non-CO2 Greenhouse gas Observing System) program since 2011. Similar research is also conducted in Central Europe, in urban area of Krakow (Poland, 50o N, 19o E) since 1997. The work discusses results from 15 years of concentration measurements (in the years 1997-2012) of selected halocarbons and SF6 in Krakow. To obtain concentrations of measured compounds the mathematical procedure has been used, where concentrations were calculated using a five points Lagrange's interpolation method. Using temporary measurement data were determined daily arithmetic means and their standard deviations. Based on these data, efficiency of Montreal Protocol legislation, implemented in Poland (The Journal of Laws No. 52) could be assessed [2]. Additionally cut-off filtration method was used to estimate trend of the base line of individual air pollutant. Rejected exceedances of base lines were corelated with meteorological characteristics of Krakow region to evaluate possible sources of pollution. The

  2. Electron scattering cross sections for SF6 and SF5CF3 at intermediate and high energies (100-10000 eV)

    International Nuclear Information System (INIS)

    Limao-Vieira, P.; Blanco, F.; Oller, J.C.; Munoz, A.; Perez, J.M.; Vinodkumar, M.; Garcia, G.; Mason, N.J.

    2005-01-01

    A modified experimental apparatus with improved angular resolution and stability has been used to measure the total electron scattering cross sections for SF 6 and SF 5 CF 3 in the energy range of 100-5000 eV. A detailed analysis of the experimental error sources is provided. The experimental results are compared with integral elastic and inelastic cross sections calculated using the independent atom model approximation and a modified single-center additivity rule for electron energies ranging from 1 to 10,000 eV. The accuracy of these approximations method is discussed through a comparison with the experimental results. Previous cross-sectional data for SF 6 are compared with the present theoretical and experimental results. For SF 5 CF 3 , we present the first electron scattering cross-sectional data for the 100-10,000 eV energy range, as well as the first empirical determination of the molecular polarizability

  3. Measurement of gas-liquid two-phase flow around horizontal tube bundle using SF6-water. Simulating high-pressure high-temperature gas-liquid two-phase flow of PWR/SG secondary coolant side at normal pressure

    International Nuclear Information System (INIS)

    Ishikawa, Atsushi; Imai, Ryoj; Tanaka, Takahiro

    2014-01-01

    In order to improve prediction accuracy of analysis code used for design and development of industrial products, technology had been developed to create and evaluate constitutive equation incorporated in analysis code. The experimental facility for PWR/SG U tubes part was manufactured to measure local void fraction and gas-liquid interfacial velocity with forming gas-liquid upward two-phase flow simulating high-pressure high-temperature secondary coolant (water-steam) rising vertically around horizontal tube bundle. The experimental facility could reproduce flow field having gas-liquid density ratio equivalent to real system with no heating using SF6 (Sulfur Hexafluoride) gas at normal temperature and pressure less than 1 MPa, because gas-liquid density ratio, surface tension and gas-liquid viscosity ratio were important parameters to determine state of gas-liquid two-phase flow and gas-liquid density ratio was most influential. Void fraction was measured by two different methods of bi-optical probe and conductivity type probe. Test results of gas-liquid interfacial velocity vs. apparent velocity were in good agreement with existing empirical equation within 10% error, which could confirm integrity of experimental facility and appropriateness of measuring method so as to set up original constitutive equation in the future. (T. Tanaka)

  4. Investigating Characteristics of N2, CO2 and CF3I in Contrast to High Current Arcs in Circuit Breakers to Choose a Suitable Substitute for SF6

    Directory of Open Access Journals (Sweden)

    V. Abbasi

    2017-09-01

    Full Text Available Specific and sensitive operation of circuit breakers makes an individual position for them in power networks. Circuit breakers are at the central gravity of variations and execution operations. Therefore, an optimum operation is the main reason to investigate about new gases to be used in MV and HV circuit breakers instead of SF6. The arc process has enormous complexity because of hydrodynamic and electromagnetic combination equations, and that is the exact reason why most of the previous simulations were processed in two-dimension analysis. But, in this paper a three-dimension simulation with sufficient results has been fully discussed. Different evaluations on the other gases have taken under study in order to find a suitable substitute instead of SF6 gas, which can also bring an optimum operation for the breakers and can be even friendly with the environment. The simulations have been carried out based on the finite element method (FEM and magneto-hydrodynamic equations. A three-dimension model under the transient state has been chosen in the simulations to find a feasible substitute for SF6 gas. The main factors of the analysis are threefold as follows: arc temperature on the different regions, the cooling ability and arc resistance. CO2, CF3I and N2 are nominated to substitute the SF6 gas and their effects on cooling ability, nozzle evaporation, contacts erosion and arc resistance will be discussed.

  5. Measurement of the figure of merit M for 1-C3F6/SF6 mixtures

    DEFF Research Database (Denmark)

    Christensen, Jørn Erik Berril; McAllister, Iain Wilson

    1997-01-01

    High precision measurements of the linear part of the Paschen curve are reported for 1-C3F6/SF6 mixtures. From these measurements, values for the pressure-reduced limiting electric field strength (E/p)lim and the associated figure of merit M are derived. These two parameters can be used to charac......High precision measurements of the linear part of the Paschen curve are reported for 1-C3F6/SF6 mixtures. From these measurements, values for the pressure-reduced limiting electric field strength (E/p)lim and the associated figure of merit M are derived. These two parameters can be used...

  6. Long-term deconditioning of gas-filled surge arresters

    Science.gov (United States)

    Stanković, Koviljka; Brajović, Dragan; Alimpijević, Mališa; Lončar, Boris

    2016-07-01

    The aim of this paper is to identify parameters that influence the long-term deconditioning effect of gas-filled surge arrester (GFSA) and to provide practical recommendations for mitigating this effect. Namely, after some period of time, on order of hours or days, during which there is no activation due to overvoltage, the deconditioning of GFSA occurs. This effect was observed experimentally within the paper. The observed parameters that could influence the long-term deconditioning effect were the following: shape of voltage load, gas type, gas pressure, interelectrode distance, electrode material, electrode surface topography as well as GFSA design such as two- or three-electrode configuration. According to the results obtained, it has been shown that the occurrence of long-term deconditioning in an insulating system, insulated by a noble gas at a subpressure and with small interelectrode distances, is a phenomenon that always occurs when the insulating system is at rest for about an hour. It has been found that the type of noble gas does not influence the long-term deconditioning. Analysis of such insulating systems' parameters, with a prospect of being used as GFSAs, has demonstrated that this phenomenon is less pronounced at higher pressures (for the same value of the pressure (p) and interelectrode distance (d) product) and for electrodes with microscopically embossed surfaces. According to the results that were obtained by noble gases and their mixtures, as well as the results that were obtained by mixtures of SF6 gas with noble gasses, it can be claimed with confidence that the effect of the long-term deconditioning is an electrode effect. It has also been established that the deconditioning effect does not depend on the electrode material except in the case of electrodes made out of noble metals, which reduce the effect. Based on these results, it can be recommended that the working point of GFSAs be set (according to the DC breakdown voltage value) at a

  7. Streamer propagation velocity to anode and to cathode in He, Xe, N2 and SF6

    International Nuclear Information System (INIS)

    Yakovlenko, S.I.

    2004-01-01

    One studied mechanism of ionization propagation in a solid gas associated with propagation of background electrons in heterogenous electric field. The mentioned mechanism does not depend on the sign of field projection on ionization propagation direction. One derived analytical expression for ionization front rate. The mentioned expression conforms well with numerical calculations. Dependence of wave ionization front rate as a function of a field intensity on boundary of streamer for He, Xe, N 2 and SF 6 is tabulated [ru

  8. SF12: Stata module to alidate sf12 input and calculate sf12 version 2 t scores

    DEFF Research Database (Denmark)

    2015-01-01

    sf12 takes 12 variables in correct order (i1 i2a i2b i3a i3b i4a i4b i5 i6a i6b i6c i7), validate the variables with respect to sf12 requirements. Only rows that are correct are used for calculating the sf12 t scores....

  9. Simulations of indirectly driven gas-filled capsules at the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Weber, S. V.; Casey, D. T.; Eder, D. C.; Pino, J. E.; Smalyuk, V. A.; Remington, B. A.; Rowley, D. P.; Yeamans, C. B.; Tipton, R. E.; Barrios, M.; Benedetti, R.; Berzak Hopkins, L.; Bleuel, D. L.; Bond, E. J.; Bradley, D. K.; Caggiano, J. A.; Callahan, D. A.; Cerjan, C. J.; Clark, D. S.; Divol, L. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); and others

    2014-11-15

    Gas-filled capsules imploded with indirect drive on the National Ignition Facility have been employed as symmetry surrogates for cryogenic-layered ignition capsules and to explore interfacial mix. Plastic capsules containing deuterated layers and filled with tritium gas provide a direct measure of mix of ablator into the gas fuel. Other plastic capsules have employed DT or D{sup 3}He gas fill. We present the results of two-dimensional simulations of gas-filled capsule implosions with known degradation sources represented as in modeling of inertial confinement fusion ignition designs; these are time-dependent drive asymmetry, the capsule support tent, roughness at material interfaces, and prescribed gas-ablator interface mix. Unlike the case of cryogenic-layered implosions, many observables of gas-filled implosions are in reasonable agreement with predictions of these simulations. Yields of TT and DT neutrons as well as other x-ray and nuclear diagnostics are matched for CD-layered implosions. Yields of DT-filled capsules are over-predicted by factors of 1.4–2, while D{sup 3}He capsule yields are matched, as well as other metrics for both capsule types.

  10. In Situ Measurements of Sulfur Hexafluoride (SF6) and age of air from NH sources during the Atmospheric Tomography (ATom) global airborne survey

    Science.gov (United States)

    Elkins, J. W.; Moore, F. L.; Hintsa, E. J.; Ray, E. A.; Dutton, G. S.; Nance, J. D.; Hall, B. D.; Dlugokencky, E. J.; Sweeney, C.; Montzka, S. A.; Newman, P. A.

    2017-12-01

    Atmospheric SF6 is an excellent tracer of atmospheric transport in the troposphere, because of its long lifetime (850 years), mostly northern hemispheric (NH) emissions (95%), and high atmospheric growth rate ( 4%/yr.). The gas is used in the distribution of electrical power, because it is an excellent insulator. It is primarily released through its use (leaking and refilling) in high voltage power transformers. Two NOAA/GMD airborne, in situ gas chromatographs (GCs), PAN and other Trace Hydrohalocarbons ExpeRiment (PANTHER) and UAS Chromatograph for Atmospheric Trace Species (UCATS), operated on the first two circuits of the Atmospheric Tomography Mission (ATom-1 & ATom-2). Both instruments measure nitrous oxide (N2O) and sulfur hexafluoride (SF6) once every 70 seconds using a very sensitive electron capture detector (ECD). We combined both measurements into one data set for analysis of twice the amount of data, since both instruments are comparable and used the same gas standards. The main purpose of ATom is to study the influence of air quality on climate during the four seasons, where two seasons are completed so far. The altitude-latitude cross sections of SF6 mixing ratios during the ATom-1 (left) shows sources are mostly located in the NH ( 95%). The upper troposphere shows inter-hemispheric mixing. The polar stratosphere shows older air that is mixed with air from the mesospheric sink. Using the procedure described by Waugh et al., (2013) [JGR-Atmos. 10.1002/jgrd.50189] and a recent growth rate of 0.32 ppt yr-1, we have calculated the mean age of each SF6 measurement from its source at ground level in the NH (lat. range of 30-50°N). The contours of age (right) are in agreement with the mean inter-hemispheric exchange time (τNS) of 1.2 yr and higher ages in the polar stratosphere (2.5-3.0 yr).

  11. Towards a liquid Argon TPC without evacuation filling of a 6$m^3$ vessel with argon gas from air to ppm impurities concentration through flushing

    CERN Document Server

    Curioni, A; Gendotti, A; Knecht, L; Lussi, D; Marchionni, A; Natterer, G; Resnati, F; Rubbia, A; Coleman, J; Lewis, M; Mavrokoridis, K; McCormick, K; Touramanis, C

    2010-01-01

    In this paper we present a successful experimental test of filling a volume of 6 $m^3$ with argon gas, starting from normal ambient air and reducing the impurities content down to few parts per million (ppm) oxygen equivalent. This level of contamination was directly monitored measuring the slow component of the scintillation light of the Ar gas, which is sensitive to $all$ sources of impurities affecting directly the argon scintillation.

  12. An interferometric and numerical study of pseudo-stationary oblique-shock-wave reflections in sulfur hexafluoride (SF6)

    Science.gov (United States)

    Hu, T. C. J.; Glass, I. I.

    Results are reported from experimental and analytical investigations of real-gas effects in the propagation of shock waves through SF6, a gas with 15 vibrational degrees of freedom. Shock waves with speeds ranging from Mach 1.25-8 were directed toward sharp steel wedges in a hypervelocity shock tube. Mach-Zehnder interferometry was used to obtain shock shape and geometry, isopycnic and density field data. Frozen-gas and equilibrium-gas (EQM) analyses modeling were performed for comparisons with experimental data, which depicted four types of reflection and transitions among them. Transition boundaries were best predicted with EQM treatment. A new criterion was derived for transition between single-Mach and complex-Mach reflection. Regular reflection continued past the boundary line defined by the transition criterion because of boundary layer growth produced on the wedge surface by passage of the shock wave.

  13. Prediction on dielectric strength and boiling point of gaseous molecules for replacement of SF6.

    Science.gov (United States)

    Yu, Xiaojuan; Hou, Hua; Wang, Baoshan

    2017-04-15

    Developing the environment-friendly insulation gases to replace sulfur hexafluoride (SF 6 ) has attracted considerable experimental and theoretical attentions but without success. A computational methodology was presented herein for prediction on dielectric strength and boiling point of arbitrary gaseous molecules in the purpose of molecular design and screening. New structure-activity relationship (SAR) models have been established by combining the density-dependent properties of the electrostatic potential surface, including surface area and the statistical variance of the surface potentials, with the molecular properties including polarizability, electronegativity, and hardness. All the descriptors in the SAR models were calculated using density functional theory. The substitution effect of SF 6 by various functional groups was studied systematically. It was found that CF 3 is the most effective functional group to improve the dielectric strength due to the large surface area and polarizability. However, all the substitutes exhibit higher boiling points than SF 6 because the molecular hardness decreases. The balance between E r and T b could be achieved by minimizing the local polarity of the molecules. SF 5 CN and SF 5 CFO were found to be the potent candidates to replace SF 6 in view of their large dielectric strengths and low boiling points. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  14. Lens subluxation after plasmin and SF6 injections in rabbit eyes.

    Directory of Open Access Journals (Sweden)

    Wei-Chi Wu

    Full Text Available To investigate the rate of lens subluxation following plasmin and/or SF6 injections in eyes, and whether a subsequent elevated level of vascular endothelial growth factor (VEGF and vitreous tap would aggravate subluxation.Four groups of rabbits were used. Group 1 received an intravitreal injection (IVI of plasmin and SF6 in the right eye; group 2 received an IVI of plasmin in the right eye; group 3 received an IVI of SF6 in the right eye; and group 4 received an IVI of balanced salt solution in the right eye. After treatment, IVIs of VEGF were given and vitreous tap was performed three times, followed by clinical observation of lens subluxation and scanning electronic microscope evaluation of the zonular fibers.After IVIs of plasmin and SF6, and VEGF and vitreous tap had been performed one to three times, lens subluxation was noted in 0%, 43%, 71%, 71%, and 86% of the eyes in group 1. After IVIs of plasmin, VEGF, and vitreous tap had been performed one to three times, lens subluxation was noted in 11%, 22%, 44%, 44%, and 67% of the eyes in group 2. The eyes in group 3 and 4 did not show signs of lens subluxation after VEGF IVIs and vitreous tap. Histology confirmed zonular fiber damage in the eyes treated with plasmin.The incidence of lens subluxation increased following plasmin injections in the eyes, and this was aggravated by the subsequent high VEGF level in the eyes and vitreous tapping. Zonular fibers were disrupted following plasmin treatment. These effects should be kept in mind when using plasmin enzymes in patients with vitreoretinal abnormalities.

  15. Transport mechanisms for synoptic, seasonal and interannual SF6 variations and "age" of air in troposphere

    Directory of Open Access Journals (Sweden)

    K. Miyazaki

    2009-02-01

    Full Text Available We use an atmospheric general circulation model (AGCM driven chemistry-transport model (ACTM to simulate the evolution of sulfur hexafluoride (SF6 in the troposphere. The model results are compared with continuous measurements at 6 sites over 71° N–90° S. These comparisons demonstrate that the ACTM simulations lie within the measurement uncertainty over the analysis period (1999–2006 and capture salient features of synoptic, seasonal and interannual SF6 variability. To understand transport timescales of SF6 within the troposphere, transport times of air parcels from the surface to different regions of the troposphere ("age" are estimated from a simulation of an idealized tracer. The age estimation error and its sensitivity to the selection of reanalysis meteorology for ACTM nudging or the tracer transport by deep cumulus convection as represented in the model are discussed. Monthly-mean, 2-box model exchange times (τex are calculated from both the observed and simulated SF6 time series at the 6 observing sites and show favorable agreement, suggesting that the ACTM adequately represents large-scale interhemispheric transport. The simulated SF6 variability is further investigated through decomposition of the mixing ratio time-tendency into advective, convective, and vertical diffusive components. The transport component analysis illustrates the role of each process in SF6 synoptic variability at the site level and provides insight into the seasonality of τex.

  16. Comparison of Sulfur Hexafluoride (SF6) and Air Tamponade in Noniridectomized Descemet Membrane Endothelial Keratoplasty.

    Science.gov (United States)

    Einan-Lifshitz, Adi; Sorkin, Nir; Boutin, Tanguy; Showail, Mahmood; Borovik, Armand; Jamshidi, Farzad; Chan, Clara C; Rootman, David S

    2018-03-01

    To compare the efficacy and safety of 20% sulfur hexafluoride gas (SF6) and air tamponade in patients who underwent noniridectomized Descemet membrane endothelial keratoplasty (DMEK). A retrospective chart review of patients who underwent DMEK with either air or SF6 tamponade: 41 eyes received air tamponade (group 1) and 41 received SF6 tamponade (group 2). Best spectacle-corrected visual acuity, endothelial cell density, and complications including graft detachment and elevated intraocular pressure were compared. The mean follow-up time was 8 ± 4 months in group 1 and 3 ± 2 months in group 2. Mean best spectacle-corrected visual acuity improved from 1.12 ± 0.88 to 0.64 ± 0.78 logarithm of the minimum angle of resolution (logMAR) in group 1 (P = 0.009) and from 1.00 ± 0.78 to 0.62 ± 0.53 logMAR in group 2 (P = 0.006). The graft detachment rate was 39% (16 eyes) in group 1 and 42% (17 eyes) in group 2 (P = 0.822). The rate of graft detachment larger than one third of the graft area was 17% in group 1 and 20% in group 2 (P = 0.775). Rebubbling was performed in 26.8% and 20% of eyes in group 1 and 2, respectively (P = 0.43). Average endothelial cell loss was 32% in group 1 and 33% in group 2 (P = 0.83). In the immediate postoperative period, elevated intraocular pressure was observed in 2 eyes (5%) in group 1 and in 4 eyes (10%) in group 2 (P = 0.4). There was 1 primary graft failure in each group. Use of air with it being readily available and short acting is a good method of Descemet membrane tamponade in noniridectomized DMEK.

  17. Gas-filled hohlraum experiments at the National Ignition Facility

    International Nuclear Information System (INIS)

    Fernandez, Juan C.; Goldman, S.R.; Kline, J.L.; Dodd, E.S.; Gautier, C.; Grim, G.P.; Hegelich, B.M.; Montgomery, D.S.; Lanier, N.E.; Rose, H.; Schmidt, D.W.; Workman, J.B.; Braun, D.G.; Dewald, E.L.; Landen, O.L.; Campbell, K.M.; Holder, J.P.; MacKinnon, A.J.; Niemann, C.; Schein, J.

    2006-01-01

    Experiments done at the National Ignition Facility laser [J. A. Paisner, E. M. Campbell, and W. Hogan, Fusion Technol. 26, 755 (1994)] using gas-filled hohlraums demonstrate a key ignition design feature, i.e., using plasma pressure from a gas fill to tamp the hohlraum-wall expansion for the duration of the laser pulse. Moreover, our understanding of hohlraum energetics and the ability to predict the hohlraum soft-x-ray drive has been validated in ignition-relevant conditions. Finally, the laser reflectivity from stimulated Raman scattering in the fill plasma, a key threat to hohlraum performance, is shown to be suppressed by choosing a design with a sufficiently high ratio of electron temperature to density

  18. Comparison of the SF6D, the EQ5D, and the oswestry disability index in patients with chronic low back pain and degenerative disc disease.

    Science.gov (United States)

    Johnsen, Lars G; Hellum, Christian; Nygaard, Oystein P; Storheim, Kjersti; Brox, Jens I; Rossvoll, Ivar; Leivseth, Gunnar; Grotle, Margreth

    2013-04-26

    The need for cost effectiveness analyses in randomized controlled trials that compare treatment options is increasing. The selection of the optimal utility measure is important, and a central question is whether the two most commonly used indexes - the EuroQuol 5D (EQ5D) and the Short Form 6D (SF6D) - can be used interchangeably. The aim of the present study was to compare change scores of the EQ5D and SF6D utility indexes in terms of some important measurement properties. The psychometric properties of the two utility indexes were compared to a disease-specific instrument, the Oswestry Disability Index (ODI), in the setting of a randomized controlled trial for degenerative disc disease. In a randomized controlled multicentre trial, 172 patients who had experienced low back pain for an average of 6 years were randomized to either treatment with an intensive back rehabilitation program or surgery to insert disc prostheses. Patients filled out the ODI, EQ5D, and SF-36 at baseline and two-year follow up. The utility indexes was compared with respect to measurement error, structural validity, criterion validity, responsiveness, and interpretability according to the COSMIN taxonomy. At follow up, 113 patients had change score values for all three instruments. The SF6D had better similarity with the disease-specific instrument (ODI) regarding sensitivity, specificity, and responsiveness. Measurement error was lower for the SF6D (0.056) compared to the EQ5D (0.155). The minimal important change score value was 0.031 for SF6D and 0.173 for EQ5D. The minimal detectable change score value at a 95% confidence level were 0.157 for SF6D and 0.429 for EQ5D, and the difference in mean change score values (SD) between them was 0.23 (0.29) and so exceeded the clinical significant change score value for both instruments. Analysis of psychometric properties indicated that the indexes are unidimensional when considered separately, but that they do not exactly measure the same

  19. High-density carbon ablator ignition path with low-density gas-filled rugby hohlraum

    International Nuclear Information System (INIS)

    Amendt, Peter; Ho, Darwin D.; Jones, Ogden S.

    2015-01-01

    A recent low gas-fill density (0.6 mg/cc 4 He) cylindrical hohlraum experiment on the National Ignition Facility has shown high laser-coupling efficiency (>96%), reduced phenomenological laser drive corrections, and improved high-density carbon capsule implosion symmetry [Jones et al., Bull. Am. Phys. Soc. 59(15), 66 (2014)]. In this Letter, an ignition design using a large rugby-shaped hohlraum [Amendt et al., Phys. Plasmas 21, 112703 (2014)] for high energetics efficiency and symmetry control with the same low gas-fill density (0.6 mg/cc 4 He) is developed as a potentially robust platform for demonstrating thermonuclear burn. The companion high-density carbon capsule for this hohlraum design is driven by an adiabat-shaped [Betti et al., Phys. Plasmas 9, 2277 (2002)] 4-shock drive profile for robust high gain (>10) 1-D ignition performance and large margin to 2-D perturbation growth

  20. High-density carbon ablator ignition path with low-density gas-filled rugby hohlraum

    Science.gov (United States)

    Amendt, Peter; Ho, Darwin D.; Jones, Ogden S.

    2015-04-01

    A recent low gas-fill density (0.6 mg/cc 4He) cylindrical hohlraum experiment on the National Ignition Facility has shown high laser-coupling efficiency (>96%), reduced phenomenological laser drive corrections, and improved high-density carbon capsule implosion symmetry [Jones et al., Bull. Am. Phys. Soc. 59(15), 66 (2014)]. In this Letter, an ignition design using a large rugby-shaped hohlraum [Amendt et al., Phys. Plasmas 21, 112703 (2014)] for high energetics efficiency and symmetry control with the same low gas-fill density (0.6 mg/cc 4He) is developed as a potentially robust platform for demonstrating thermonuclear burn. The companion high-density carbon capsule for this hohlraum design is driven by an adiabat-shaped [Betti et al., Phys. Plasmas 9, 2277 (2002)] 4-shock drive profile for robust high gain (>10) 1-D ignition performance and large margin to 2-D perturbation growth.

  1. High-density carbon ablator ignition path with low-density gas-filled rugby hohlraum

    Energy Technology Data Exchange (ETDEWEB)

    Amendt, Peter; Ho, Darwin D.; Jones, Ogden S. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

    2015-04-15

    A recent low gas-fill density (0.6 mg/cc {sup 4}He) cylindrical hohlraum experiment on the National Ignition Facility has shown high laser-coupling efficiency (>96%), reduced phenomenological laser drive corrections, and improved high-density carbon capsule implosion symmetry [Jones et al., Bull. Am. Phys. Soc. 59(15), 66 (2014)]. In this Letter, an ignition design using a large rugby-shaped hohlraum [Amendt et al., Phys. Plasmas 21, 112703 (2014)] for high energetics efficiency and symmetry control with the same low gas-fill density (0.6 mg/cc {sup 4}He) is developed as a potentially robust platform for demonstrating thermonuclear burn. The companion high-density carbon capsule for this hohlraum design is driven by an adiabat-shaped [Betti et al., Phys. Plasmas 9, 2277 (2002)] 4-shock drive profile for robust high gain (>10) 1-D ignition performance and large margin to 2-D perturbation growth.

  2. MV controlled spark gap

    International Nuclear Information System (INIS)

    Evdokimovich, V.M.; Evlampiev, S.B.; Korshunov, G.S.; Nikolaev, V.A.; Sviridov, Yu.F.; Khmyrov, V.V.

    1980-01-01

    A megavolt gas-filled trigatron gap with a sectional gas-discharge chamber having a more than three-fold range of operating voltages is described. The discharge chamber consists of ten sections, each 70 mm thick, made of organic glass. The sections are separated one from another by aluminium gradient rings to which ohmic voltage divider is connected. Insulational sections and gradient rings are braced between themselves by means of metal flanges through gaskets made of oil-resistant rubber with the help of fiberglass-laminate pins. The gap has two electrodes 110 mm in diameter. The trigatron ignition assembly uses a dielectric bushing projecting over the main electrode plane. Use has been made of a gas mixture containing 10% of SF 6 and 90% of air making possible to ensure stable gap operation without readjusting in the voltage range from 0.4 to 1.35 MV. The operation time lag in this range is equal to 10 μs at a spread of [ru

  3. Two-temperature thermodynamic and transport properties of SF6–Cu plasmas

    International Nuclear Information System (INIS)

    Wu, Yi; Chen, Zhexin; Yang, Fei; Rong, Mingzhe; Sun, Hao; Cressault, Yann; Murphy, Anthony B; Guo, Anxiang; Liu, Zirui

    2015-01-01

    SF 6 and Cu are widely adopted in electrical equipment as a dielectric medium and for conductive components, respectively. SF 6 –Cu plasmas are frequently formed, particularly in high-voltage circuit breaker arcs and fault current arcs, due to erosion of the Cu components. In this paper, calculated values of the thermodynamic and transport properties of plasmas in SF 6 –Cu mixtures are presented for both thermal equilibrium and non-equilibrium conditions. The composition is determined by the two-temperature Saha equation and Guldberg–Waage equation in the form derived by van de Sanden. The composition and the thermodynamic properties are evaluated through a classical statistical mechanics approach. For the transport coefficients, the simplified Chapman–Enskog method developed by Devoto, which decouples the electrons and heavy species, has been applied using the most recent collision integrals. The thermodynamic and transport properties are calculated for different electron temperatures (300–40 000 K), ratios of electron to heavy-species temperature (1–10), pressures (0.1–10 atm) and copper molar proportions (0–50%). It is found that deviations from thermal equilibrium strongly affect the thermodynamic and transport properties of the SF 6 –Cu plasmas. Further, the presence of copper has different effects on some of the properties for plasmas in and out of thermal equilibrium. The main reason for these changes is that dissociation reactions are delayed for non-thermal equilibrium plasmas, which in turn influences the ionization reactions that occur. (paper)

  4. High pressure gas-filled cermet spark gaps

    International Nuclear Information System (INIS)

    Avilov, Eh.A.; Yur'ev, A.L.

    2000-01-01

    The results of modernization of the R-48 and R-49 spark gaps making it possible to improve their electrical characteristics are presented. The design is described and characteristics of gas-filled cermet spark gaps are presented. By the voltage rise time of 5-6 μs in the Marx generator scheme they provide for the pulse break-through voltage of 120 and 150 kV. By the voltage rise time of 0.5-1 μs the break-through voltage of these spark gaps may be increased up to 130 and 220 kV. The proper commutation time is equal to ≤ 0.5 ns. Practical recommendations relative to designing cermet spark gaps are given [ru

  5. Gas-filled capillaries for plasma-based accelerators

    International Nuclear Information System (INIS)

    Filippi, F; Anania, M P; Brentegani, E; Biagioni, A; Chiadroni, E; Ferrario, M; Pompili, R; Romeo, S; Cianchi, A; Zigler, A

    2017-01-01

    Plasma Wakefield Accelerators are based on the excitation of large amplitude plasma waves excited by either a laser or a particle driver beam. The amplitude of the waves, as well as their spatial dimensions and the consequent accelerating gradient depend strongly on the background electron density along the path of the accelerated particles. The process needs stable and reliable plasma sources, whose density profile must be controlled and properly engineered to ensure the appropriate accelerating mechanism. Plasma confinement inside gas filled capillaries have been studied in the past since this technique allows to control the evolution of the plasma, ensuring a stable and repeatable plasma density distribution during the interaction with the drivers. Moreover, in a gas filled capillary plasma can be pre-ionized by a current discharge to avoid ionization losses. Different capillary geometries have been studied to allow the proper temporal and spatial evolution of the plasma along the acceleration length. Results of this analysis obtained by varying the length and the number of gas inlets will be presented. (paper)

  6. Gas-filled capillaries for plasma-based accelerators

    Science.gov (United States)

    Filippi, F.; Anania, M. P.; Brentegani, E.; Biagioni, A.; Cianchi, A.; Chiadroni, E.; Ferrario, M.; Pompili, R.; Romeo, S.; Zigler, A.

    2017-07-01

    Plasma Wakefield Accelerators are based on the excitation of large amplitude plasma waves excited by either a laser or a particle driver beam. The amplitude of the waves, as well as their spatial dimensions and the consequent accelerating gradient depend strongly on the background electron density along the path of the accelerated particles. The process needs stable and reliable plasma sources, whose density profile must be controlled and properly engineered to ensure the appropriate accelerating mechanism. Plasma confinement inside gas filled capillaries have been studied in the past since this technique allows to control the evolution of the plasma, ensuring a stable and repeatable plasma density distribution during the interaction with the drivers. Moreover, in a gas filled capillary plasma can be pre-ionized by a current discharge to avoid ionization losses. Different capillary geometries have been studied to allow the proper temporal and spatial evolution of the plasma along the acceleration length. Results of this analysis obtained by varying the length and the number of gas inlets will be presented.

  7. Gas transfer system

    International Nuclear Information System (INIS)

    Oberlin, J.C.; Frick, G.; Kempfer, C.; North, C.

    1988-09-01

    The state of work on the Vivitron gas transfer system and the system functions are summarized. The system has to: evacuate the Vivitron reservoir; transfer gas from storage tanks to the Vivitron; recirculate gas during operation; transfer gas from the Vivitron to storage tanks; and assure air input. The system is now being installed. Leak alarms are given by SF6 detectors, which set off a system of forced ventilation. Another system continuously monitors the amount of SF6 in the tanks [fr

  8. Interlaboratory comparison of SF6-determinations used within the framework of tracer releases

    International Nuclear Information System (INIS)

    Vanderborght, B.

    1985-01-01

    An international intercomparison exercise, for determination of trace amounts of SF 6 in air was set up, to make interchange of experimental results or common tracer experiments possible between European laboratories. SCK, Belgium made 6 SF 6 samples in the 10 ppt to 10 ppb range. Samples were analyzed by CEN (F), CERL (UK), JRC (I), KEMA (NL), LHW (NL), NILU (N), APL (DK), WDB (FRG) and SCK (B). Very good agreement was obtained between SCK, CERL, APL and NILU. LHW and KEMA obtained systematically lower results than those four laboratories; the problem might originate in manufacturing of mother samples under high pressure. CEN and WDB work in a higher concentration range and their analysis of trace amounts is less accurate. JRC samples were contaminated and accuracy of their analysis cannot be evaluated. SF 6 samples in PVC plastic bags are not stable enough over long periods, especially with ambient temperature higher than 30 0 C. Transport of samples in plastic bags over long distances is not advisable when transport conditions cannot be well controlled

  9. Simulation of the Process of Arc Energy-Effect in High Voltage Auto-Expansion SF6 Circuit Breaker

    International Nuclear Information System (INIS)

    Rong Mingzhe; Yang Qian; Fan Chunduo

    2005-01-01

    A new magnetic hydro-dynamics (MHD) model of arc in H.V. auto-expansion SF 6 circuit breaker that takes into consideration nozzle ablation due to both radiation and thermal conduction is presented in this paper. The effect of PTFE (polytetrafluorethylene) vapor is considered in the mass, momentum and energy conservation equations of the constructed model. Then, the gas flow fields with and without conduction considered are simulated. By comparing the aforementioned two results, it is indicated that the arc's maximal temperature with conduction considered is 90 percent of that without considering conduction

  10. Amorphous hydrogenated carbon films treated by SF{sub 6} plasma

    Energy Technology Data Exchange (ETDEWEB)

    Marins, N M S; Mota, R P; Santos, D C R; Honda, R Y; Kayama, M E; Kostov, K G; Algatti, M A [Laboratorio de Plasma, Faculdade de Engenharia, UNESP, Av. Dr. Ariberto Pereira da Cunha-333, 12516-410, Guaratingueta, SP (Brazil); Cruz, N C; Rangel, E C, E-mail: nazir@feg.unesp.b [Laboratorio de Plasmas Tecnologicos, Unidade Diferenciada Sorocaba/Ipero, UNESP, Av. Tres de Marco-511, 18085-180, Sorocaba, SP (Brazil)

    2009-05-01

    This work was performed to verify the chemical structure, mechanical and hydrophilic properties of amorphous hydrogenated carbon films prepared by plasma enhanced chemical vapor deposition, using acetylene/argon mixture as monomer. Films were prepared in a cylindrical quartz reactor, fed by 13.56 MHz radiofrequency. The films were grown during 5 min, for power varying from 25 to 125 W at a fixed pressure of 9.5 Pa. After deposition, all samples were treated by SF{sub 6} plasma with the aim of changing their hydrophilic character. Film chemical structure investigated by Raman spectroscopy, revealed the increase of sp{sup 3} hybridized carbon bonds as the plasma power increases. Hardness measurements performed by the nanoindentation technique showed an improvement from 5 GPa to 14 GPa following the increase discharge power. The untreated films presented a hydrophilic character, which slightly diminished after SF{sub 6} plasma treatment.

  11. Inactivation of Gram-Negative Bacteria by Low-Pressure RF Remote Plasma Excited in N2-O2 Mixture and SF6 Gases

    Directory of Open Access Journals (Sweden)

    Ayman Al-Mariri

    2013-12-01

    Full Text Available The role of low-pressure RF plasma in the inactivation of Escherichia coli O157, Klebsiella pneumoniae, Proteus mirabilis, and Enterobacter sakazakii using N2-O2 and SF6 gases was assessed. 1×109 colony-forming units (CFUs of each bacterial isolate were placed on three polymer foils. The effects of pressure, power, distance from the source, and exposure time to plasma gases were optimized. The best conditions to inactivate the four bacteria were a 91%N2-9%O2 mixture and a 30-minute exposure time. SF6 gas was more efficient for all the tested isolates in as much as the treatment time was reduced to only three minutes. Therefore, low-pressure plasma could be used to sterilize heat and/or moisture-sensitive medical instruments.

  12. Experimental Study of High-Z Gas Buffers in Gas-Filled ICF Engines

    Energy Technology Data Exchange (ETDEWEB)

    Rhodes, M A; Kane, J; Loosmore, G; DeMuth, J; Latkowski, J

    2010-12-03

    ICF power plants, such as the LIFE scheme at LLNL, may employ a high-Z, target-chamber gas-fill to moderate the first-wall heat-pulse due to x-rays and energetic ions released during target detonation. To reduce the uncertainties of cooling and beam/target propagation through such gas-filled chambers, we present a pulsed plasma source producing 2-5 eV plasma comprised of high-Z gases. We use a 5-kJ, 100-ns theta discharge for high peak plasma-heating-power, an electrode-less discharge for minimizing impurities, and unobstructed axial access for diagnostics and beam (and/or target) propagation studies. We will report on the plasma source requirements, design process, and the system design.

  13. Estimating health state utility values for comorbid health conditions using SF-6D data.

    Science.gov (United States)

    Ara, Roberta; Brazier, John

    2011-01-01

    When health state utility values for comorbid health conditions are not available, data from cohorts with single conditions are used to estimate scores. The methods used can produce very different results and there is currently no consensus on which is the most appropriate approach. The objective of the current study was to compare the accuracy of five different methods within the same dataset. Data collected during five Welsh Health Surveys were subgrouped by health status. Mean short-form 6 dimension (SF-6D) scores for cohorts with a specific health condition were used to estimate mean SF-6D scores for cohorts with comorbid conditions using the additive, multiplicative, and minimum methods, the adjusted decrement estimator (ADE), and a linear regression model. The mean SF-6D for subgroups with comorbid health conditions ranged from 0.4648 to 0.6068. The linear model produced the most accurate scores for the comorbid health conditions with 88% of values accurate to within the minimum important difference for the SF-6D. The additive and minimum methods underestimated or overestimated the actual SF-6D scores respectively. The multiplicative and ADE methods both underestimated the majority of scores. However, both methods performed better when estimating scores smaller than 0.50. Although the range in actual health state utility values (HSUVs) was relatively small, our data covered the lower end of the index and the majority of previous research has involved actual HSUVs at the upper end of possible ranges. Although the linear model gave the most accurate results in our data, additional research is required to validate our findings. Copyright © 2011 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  14. The Mounting process and dielectric tests of the Parque Caballero armored substation in SF6(220 Kv); Montaje y pruebas dielectricas de la estacion blindada en gas SF6 (220 kV) 'Parque Caballero'

    Energy Technology Data Exchange (ETDEWEB)

    Decoud, Carlos; Bobadilla, Alberto [ANDE - Administracion Nacional de Electricidad, Assuncion (Paraguay)

    2001-07-01

    This document approaches the aspects referring to the mounting and also dielectric tests for the Parque Caballero armored substation in SF6. This type of installation represents a innovation regarding substations in urban centres. The most relevant items in relation to the mounting process are shown in a summarized way, as well as the aspects related to dielectric tests executed during the substation commissioning.

  15. The relationship between gas fill density and hohlraum drive performance at the National Ignition Facility

    Science.gov (United States)

    Hall, G. N.; Jones, O. S.; Strozzi, D. J.; Moody, J. D.; Turnbull, D.; Ralph, J.; Michel, P. A.; Hohenberger, M.; Moore, A. S.; Landen, O. L.; Divol, L.; Bradley, D. K.; Hinkel, D. E.; Mackinnon, A. J.; Town, R. P. J.; Meezan, N. B.; Berzak Hopkins, L.; Izumi, N.

    2017-05-01

    Indirect drive inertial confinement fusion experiments were conducted at the National Ignition Facility to investigate the performance of the hohlraum drive as a function of hohlraum gas fill density by imploding high-density-carbon capsules using a 2-shock laser pulse. Measurements characterized the backscatter behavior, the production of hot electrons, the motion and brightness of the laser spots on the hohlraum wall, and the efficiency of the hohlraum x-ray drive as a function of gas fill density ρgf between 0.03 mg/cc ("near vacuum") and 1.6 mg/cc. For hohlraums with ρgf up to 0.85 mg/cc, very little stimulated Raman backscatter (SRS) was observed. For higher ρgf, significant SRS was produced and was observed to occur during the rise to peak laser power and throughout the main pulse. The efficiency with which laser energy absorbed by the hohlraum is converted into drive energy was measured to be the same for ρgf ≥ 0.6 mg/cc once the laser reached peak power. However, for the near vacuum case, the absorbed energy was converted to drive energy more efficiently throughout the pulse and maintained an efficiency ˜10% higher than the gas filled hohlraums throughout the main pulse.

  16. Computational modeling of intraocular gas dynamics

    International Nuclear Information System (INIS)

    Noohi, P; Abdekhodaie, M J; Cheng, Y L

    2015-01-01

    The purpose of this study was to develop a computational model to simulate the dynamics of intraocular gas behavior in pneumatic retinopexy (PR) procedure. The presented model predicted intraocular gas volume at any time and determined the tolerance angle within which a patient can maneuver and still gas completely covers the tear(s). Computational fluid dynamics calculations were conducted to describe PR procedure. The geometrical model was constructed based on the rabbit and human eye dimensions. SF_6 in the form of pure and diluted with air was considered as the injected gas. The presented results indicated that the composition of the injected gas affected the gas absorption rate and gas volume. After injection of pure SF_6, the bubble expanded to 2.3 times of its initial volume during the first 23 h, but when diluted SF_6 was used, no significant expansion was observed. Also, head positioning for the treatment of retinal tear influenced the rate of gas absorption. Moreover, the determined tolerance angle depended on the bubble and tear size. More bubble expansion and smaller retinal tear caused greater tolerance angle. For example, after 23 h, for the tear size of 2 mm the tolerance angle of using pure SF_6 is 1.4 times more than that of using diluted SF_6 with 80% air. Composition of the injected gas and conditions of the tear in PR may dramatically affect the gas absorption rate and gas volume. Quantifying these effects helps to predict the tolerance angle and improve treatment efficiency. (paper)

  17. Gas-filled hohlraum experiments at the national ignition facility.

    Energy Technology Data Exchange (ETDEWEB)

    Fernández, J. C. (Juan C.); Gautier, D. C. (Donald Cort); Goldman, S. R. (Sanford R.); Grimm, B. M.; Hegelich, B. M. (Bjorn M.); Kline, J. L. (John L.); Montgomery, D. S. (David S.); Lanier, N. E. (Nicholas E.); Rose, H. A. (Harvey A.); Schmidt, D. M. (David M.); Swift, D. C.; Workman, J. B. (Jonathan B.); Alvarez, Sharon; Bower, Dan.; Braun, Dave.; Campbell, K. (Katherine); DeWald, E.; Glenzer, S. (Siegfried); Holder, J. (Joe P.); Kamperschroer, J. H. (James H.); Kimbrough, Joe (Joseph R.); Kirkwood, Robert (Bob); Landen, O. L. (Otto L.); Mccarville, Tom (Tomas J.); Macgowan, B.; Mackinnon, A.; Niemann, C.; Schein, J.; Schneider, M; Watts, Phil; Young, Ben-li [number : znumber] 194154; Young B.

    2004-01-01

    The summary of this paper is: (1) We have fielded on NIF a gas-filled hohlraum designed for future ignition experiments; (2) Wall-motion measurements are consistent with LASNEX simulations; (3) LPI back-scattering results have confounded expectations - (a) Stimulated Brillouin (SBS) dominates Raman (SRS) for any gas-fill species, (b) Measured SBS time-averaged reflectivity values are high, peak values are even higher, (c) SRS and SBS peak while laser-pulse is rising; and (4) Plasma conditions at the onset of high back-scattering yield high SBS convective linear gain - Wavelengths of the back-scattered light is predicted by linear theory.

  18. Gas-filled hohlraum experiments at the national ignition facility

    International Nuclear Information System (INIS)

    Fernandez, J.C.; Gautier, D.C.; Goldman, S.R.; Grimm, B.M.; Hegelich, B.M.; Kline, J.L.; Montgomery, D.S.; Lanier, N.E.; Rose, H.A.; Schmidt, D.M.; Swift, D.C.; Workman, J.B.; Alvarez, Sharon; Bower, Dan; Braun, Dave; Campbell, K.; DeWald, E.; Glenzer, S.; Holder, J.; Kamperschroer, J.H.; Kimbrough, Joe; Kirkwood, Robert; Landen, O.L.; Mccarville, Tom; Macgowan, B.; Mackinnon, A.; Niemann, C.; Schein, J.; Schneider, M.; Watts, Phil; Young, Ben-li; Young B.

    2004-01-01

    The summary of this paper is: (1) We have fielded on NIF a gas-filled hohlraum designed for future ignition experiments; (2) Wall-motion measurements are consistent with LASNEX simulations; (3) LPI back-scattering results have confounded expectations - (a) Stimulated Brillouin (SBS) dominates Raman (SRS) for any gas-fill species, (b) Measured SBS time-averaged reflectivity values are high, peak values are even higher, (c) SRS and SBS peak while laser-pulse is rising; and (4) Plasma conditions at the onset of high back-scattering yield high SBS convective linear gain - Wavelengths of the back-scattered light is predicted by linear theory.

  19. Energy and Climate Change. The Policy of the Bush Administration and the American Public Debate

    International Nuclear Information System (INIS)

    Noel, Pierre; Reiner, David

    2008-01-01

    In its oil and energy security policy, the Bush Administration has shown a willingness to serve industrial and regional interests while relying on rhetoric of crisis - energy crisis and national security crisis. The 'Bush energy plan' of stimulating internal energy production by weakening environmental and other regulations has failed politically. In climate change policy, the Bush Administration decided not to sign the Kyoto protocol as well as not to regulate greenhouse gas emissions in the U.S. This policy has had far reaching adverse consequences for the Bush Administration, in both domestic and foreign politics. The Administration has failed at making its technology-only approach accepted as a credible alternative to regulating emissions

  20. Stress and gas hydrate-filled fracture distribution, Krishna-Godavari Basin, India

    Energy Technology Data Exchange (ETDEWEB)

    Cook, A.; Goldberg, D. [Lamont-Doherty Earth Observatory of Columbia Univ., Palisades, NY (United States)

    2008-07-01

    The first expedition of the Indian National Gas Hydrate Program (NGHP) was launched in the summer of 2006 to characterize the presence of gas hydrates on the continental margins of India. This paper presented a study from the NGHP expedition that found high resistivity fractures in unconsolidated clay sediments on logging-while-drilling (LWD) borehole resistivity images. Gas hydrate-filled and conductive fractures appearing on LWD resistivity images in holes 5A, 5B, 6A, 7A and 10 were analysed and discussed. Fracture orientation and shallow sediment stress orientations were determined for each hole. The paper described how to determine which sections of a log are hydrate bearing as well as how to calculate the predicted water saturated resistivity. It was concluded that holes 5A, 5B, 6A and 7A contained well-ordered, high-angle fractures, from which horizontal stress directions could be accurately resolved. However, these stress directions, contradicted the orientations normally seen on a passive margin, and may be the result of local bathymetry variations. 6 refs., 1 tab., 11 figs.

  1. Fungal cultures of tar bush and creosote bush for production of two phenolic antioxidants (pyrocatechol and gallic acid).

    Science.gov (United States)

    Ventura, J; Gutiérrez-Sanchez, G; Rodríguez-Herrera, R; Aguilar, C N

    2009-01-01

    'Tar bush' and 'creosote bush' were substrates of fungal cultivation for tannase production and gallic acid and pyrocatechol accumulation. Aspergillus niger GH1 grew similarly on both plant materials under solid state culture conditions, reaching maximal levels after 4 d. Fungal strain degraded all tannin content of creosote bush after 4 d of fermentation and >75 % of tar bush after 5 d. Higher level of tannase activity was detected in tar bush fermentation. Biotransformation of tannins to gallic acid was high (93 % in creosote bush and 89 % in tar bush). Pyrocatechol was released poorly. Kinetic parameters of tannin conversion were calculated.

  2. Optimizing the switching time for 400 kV SF6 circuit breakers

    Science.gov (United States)

    Ciulica, D.

    2018-01-01

    This paper presents real-time voltage and current analysis for optimizing the wave switching point of the circuit breaker SF6. Circuit Breaker plays an important role in power systems. It provides protection for equipment in embedded stations in transport networks. SF6 Circuit Breaker is very important equipment in Power Systems, which is used for up to 400 kV due to its excellent performance. The controlled switching is used to eliminate transient modes and electrodynamic and dielectric charges in the network at manual switching of capacitor, shunt reactors and power transformers. These effects reduce the reliability and lifetime of the equipment installed on the network, or may lead to erroneous protection.

  3. INS gas-filled recoil isotope separator

    International Nuclear Information System (INIS)

    Miyatake, M.; Nomura, T.; Kawakami, H.

    1986-09-01

    The characteristics and performance of a small sized gas-filled recoil isotope separator recently made at INS are described. The total efficiency and the ΔBρ/Bρ values have been measured using low velocity 16 O, 40 Ar and 68 As ions and found to be 10 and 5 %, respectively. The Z-dependence of the mean charge is discussed. (author)

  4. TM6SF2 and MAC30, new enzyme homologues in sterol metabolism and common metabolic disease.

    Directory of Open Access Journals (Sweden)

    Luis eSanchez-Pulido

    2014-12-01

    Full Text Available Carriers of the Glu167Lys coding variant in the TM6SF2 gene have recently been identified as being more susceptible to non-alcoholic fatty liver disease (NAFLD, yet exhibit lower levels of circulating lipids and hence are protected against cardiovascular disease. Despite the physiological importance of these observations, the molecular function of TM6SF2 remains unknown, and no sequence similarity with functionally characterised proteins has been identified. In order to trace its evolutionary history and to identify functional domains, we embarked on a computational protein sequence analysis of TM6SF2. We identified a new domain, the EXPERA domain, which is conserved among TM6SF, MAC30/TMEM97 and EBP (D8,D7 sterol isomerase protein families. EBP mutations are the cause of chondrodysplasia punctata 2 X-linked dominant (CDPX2, also known as Conradi-Hünermann-Happle syndrome, a defective cholesterol biosynthesis disorder. Our analysis of evolutionary conservation among EXPERA domain-containing families and the previously suggested catalytic mechanism for the EBP enzyme, indicate that TM6SF and MAC30/TMEM97 families are both highly likely to possess, as for the EBP family, catalytic activity as sterol isomerases. This unexpected prediction of enzymatic functions for TM6SF and MAC30/TMEM97 is important because it now permits detailed experiments to investigate the function of these key proteins in various human pathologies, from cardiovascular disease to cancer.

  5. Predicting SF-6D utility scores from the Oswestry disability index and numeric rating scales for back and leg pain.

    Science.gov (United States)

    Carreon, Leah Y; Glassman, Steven D; McDonough, Christine M; Rampersaud, Raja; Berven, Sigurd; Shainline, Michael

    2009-09-01

    Cross-sectional cohort. The purpose of this study is to provide a model to allow estimation of utility from the Short Form (SF)-6D using data from the Oswestry Disability Index (ODI), Back Pain Numeric Rating Scale (BPNRS), and the Leg Pain Numeric Rating Scale (LPNRS). Cost-utility analysis provides important information about the relative value of interventions and requires a measure of utility not often available from clinical trial data. The ODI and numeric rating scales for back (BPNRS) and leg pain (LPNRS), are widely used disease-specific measures for health-related quality of life in patients with lumbar degenerative disorders. The purpose of this study is to provide a model to allow estimation of utility from the SF-6D using data from the ODI, BPNRS, and the LPNRS. SF-36, ODI, BPNRS, and LPNRS were prospectively collected before surgery, at 12 and 24 months after surgery in 2640 patients undergoing lumbar fusion for degenerative disorders. Spearman correlation coefficients for paired observations from multiple time points between ODI, BPNRS, and LPNRS, and SF-6D utility scores were determined. Regression modeling was done to compute the SF-6D score from the ODI, BPNRS, and LPNRS. Using a separate, independent dataset of 2174 patients in which actual SF-6D and ODI scores were available, the SF-6D was estimated for each subject and compared to their actual SF-6D. In the development sample, the mean age was 52.5 +/- 15 years and 34% were male. In the validation sample, the mean age was 52.9 +/- 14.2 years and 44% were male. Correlations between the SF-6D and the ODI, BPNRS, and LPNRS were statistically significant (P < 0.0001) with correlation coefficients of 0.82, 0.78, and 0.72, respectively. The regression equation using ODI, BPNRS,and LPNRS to predict SF-6D had an R of 0.69 and a root mean square error of 0.076. The model using ODI alone had an R of 0.67 and a root mean square error of 0.078. The correlation coefficient between the observed and estimated

  6. Application of multiple tracers (SF6 and chloride) to identify the transport by characteristics of contaminant at two separate contaminated sites

    Science.gov (United States)

    Lee, K. K.; Lee, S. S.; Kim, H. H.; Koh, E. H.; Kim, M. O.; Lee, K.; Kim, H. J.

    2016-12-01

    Multiple tracers were applied for source and pathway detection at two different sites. CO2 gas injected in the subsurface for a shallow-depth CO2 injection and leak test can be regarded as a potential contaminant source. Therefore, it is necessary to identify the migration pattern of CO2 gas. Also, at a DNAPL contaminated site, it is important to figure out the characteristics of plume evolution from the source zone. In this study, multiple tracers (SF6 and chloride) were used to evaluate the applicability of volatile and non-volatile tracers and to identify the characteristics of contaminant transport at each CO2 injection and leak test site and DNAPL contaminated site. Firstly, at the CO2 test site, multiple tracers were used to perform the single well push-drift-pull tracer test at total 3 specific depth zones. As results of tests, volatile and non-volatile tracers showed different mass recovery percentage. Most of chloride mass was recovered but less than half of SF6 mass was recovered due to volatile property. This means that only gaseous SF6 leak out to unsaturated zone. However, breakthrough curves of both tracers indicated similar peak time, effective porosity, and regional groundwater velocity. Also, at both contaminated sites, natural gradient tracer tests were performed with multiple tracers. With the results of natural gradient tracer test, it was possible to confirm the applicability of multiple tracers and to understand the contaminant transport in highly heterogeneous aquifer systems through the long-term monitoring of tracers. Acknowledgement: financial support was provided by the R&D Project on Environmental Management of Geologic CO2 Storage)" from the KEITI (Project Number: 2014001810003) and Korea Ministry of Environment as "The GAIA project (2014000540010)".

  7. Ozone depleting substances and gases HFCs, PFCs and SF{sub 6}. Consumption and emissions 2003; Ozonlagsnedbrydende stoffer og drivhusgasserne HFC'er PFC'er og SF6. Forbrug og emissioner 2003

    Energy Technology Data Exchange (ETDEWEB)

    Sander Poulsen, T.

    2005-07-01

    The evaluation includes a calculation of actual emissions of HFCs, PFCs and SF{sub 6} in Denmark. In this calculation of actual emissions, the release from stock of greenhouse gases in products has been taken into account, and adjustments have been made for imports and exports of the greenhouse gases in products. The evaluation has partly been prepared to enable Denmark to fulfil its international obligations to provide information within this area, and partly to follow the trend in consumption and emissions of HFCs, PFCs and SF{sub 6}. (BA)

  8. Exome-wide association study identifies a TM6SF2 variant that confers susceptibility to nonalcoholic fatty liver disease

    DEFF Research Database (Denmark)

    Kozlitina, Julia; Smagris, Eriks; Stender, Stefan

    2014-01-01

    Nonalcoholic fatty liver disease (NAFLD) is the most common form of liver disease. To elucidate the molecular basis of NAFLD, we performed an exome-wide association study of liver fat content. Three variants were associated with higher liver fat levels at the exome-wide significance level of 3.......6 × 10(-7): two in PNPLA3, an established locus for NAFLD, and one (encoding p.Glu167Lys) in TM6SF2, a gene of unknown function. The TM6SF2 variant encoding p.Glu167Lys was also associated with higher circulating levels of alanine transaminase, a marker of liver injury, and with lower levels of low...... knockdown of Tm6sf2 in mice increased liver triglyceride content by threefold and decreased very-low-density lipoprotein (VLDL) secretion by 50%. Taken together, these data indicate that TM6SF2 activity is required for normal VLDL secretion and that impaired TM6SF2 function causally contributes to NAFLD....

  9. Electromagnetic radiations from laser interaction with gas-filled Hohlraum

    Science.gov (United States)

    Yang, Ming; Yang, Yongmei; Li, Tingshuai; Yi, Tao; Wang, Chuanke; Liu, Shenye; Jiang, Shaoen; Ding, Yongkun

    2018-01-01

    The emission of intensive electromagnetic pulse (EMP) due to laser-target interactions at the ShenGuang-III laser facility has been evaluated by probes. EMP signals measured using the small discone antennas demonstrated two variation trends including a bilateral oscillation wave and a unilateral oscillation wave. The new trend of unilateral oscillation could be attributed to the hohlraum structure and low-Z gas in the hohlraum. The EMP waveform showed multiple peaks when the gas-filled hohlraum was shot by the high-power laser. Comparing the EMP signals with the verification of stimulated Raman scattering energy and hard x-ray energy spectrum, we found that the intensity of EMP signals decreased with the increase of the hohlraum size. The current results are expected to offer preliminary information to study physical processes on laser injecting gas-filled hohlraums in the National Ignition Facility implementation.

  10. Bush telegraph readings in writing

    CERN Document Server

    Strongman, Luke

    2015-01-01

    A ""bush telegraph"" is an antipodean slang noun phrase for a ""grapevine"" or an informal network of communication. The title of this book on English language use comes from the fact that the book is written from the southern hemisphere (where the idea of a ""bush telegraph"" is more widely-known) and because the concept of a ""bush telegraph"" describes what the book provides - a discussion of salient points in English language use and tertiary teaching across branches of interrelated interests. Each chapter of Bush Telegraph describes aspects of English writing culture. Separately and toget

  11. Molecular bonding in SF6 measured by elastic electron scattering

    International Nuclear Information System (INIS)

    Miller, J.D.; Fink, M.

    1992-01-01

    Elastic differential cross-section measurements of gaseous SF 6 were made with 30 keV electrons in the range of 0.25 bohrs -1 ≤s≤10 bohrs -1 . Structural parameters derived in this study closely matched those found in an earlier total (elastic plus inelastic) scattering investigation. Multiple-scattering effects were incorporated in the structural refinement. The discrepancies between the independent atom model and the measured differential cross section reproduce earlier total scattering results for momentum transfers of greater than 5 bohrs -1 . By extending the measurements to smaller s values, a closer examination of a Hartree--Fock calculation for SF 6 was possible. It was found that the difference curve obtained from the Hartree--Fock calculation matched the experimental data in this region. A more quantitative analysis was performed using the analytic expressions of Bonham and Fink to compute moments of the molecular charge distribution from the differential cross-section data. Comparison of these results with similar fits to the Hartree--Fock calculation confirmed the good agreement between the Hartree--Fock calculation and the current elastic data

  12. Determining Health-Related Quality-of-Life Outcomes Using the SF-6D Following Total Hip Arthroplasty.

    Science.gov (United States)

    Elmallah, Randa K; Chughtai, Morad; Adib, Farshad; Bozic, Kevin J; Kurtz, Steven M; Mont, Michael A

    2017-03-15

    Following total hip arthroplasty, patients' perception of their postoperative improvement and health plays a large role in satisfaction with and success of the surgical procedure. The Short Form-6D (SF-6D) is a health-related quality-of-life measure that assigns numerical value to the perception of patients' own health. The purpose was to determine SF-6D values of patients after total hip arthroplasty, to determine whether score changes were clinically relevant, and to compare these with postoperative functional improvements. We evaluated 188 patients who underwent primary total hip arthroplasty at 7 institutions and who had a mean age of 69 years (range, 47 to 88 years) and a mean body mass index of 28.8 kg/m (range, 19.8 to 38.9 kg/m). The SF-6D values were obtained from patients' SF-36 scores, and clinical relevance of value changes was determined using effect size. Using previous research, effect sizes were considered small between 0.2 and 0.5, moderate between 0.6 to 0.8, and large at >0.8. Clinical correlation was assessed using the Lower-Extremity Activity Scale and Harris hip scores. Patients were assessed preoperatively and postoperatively at 6 months and 1, 2, 3, and 5 years. The SF-6D scores improved from preoperatively and achieved significance (p < 0.05) at all points. The effect size demonstrated good clinical relevance up to the latest follow-up: 1.27 at 6 months, 1.30 at 1 year, 1.07 at 2 years, 1.08 at 3 years, and 1.05 at 5 years. The Lower-Extremity Activity Scale improved at all follow-up points from preoperatively to 1.8 at 6 months, 2.0 at 1 year, 1.8 at 2 years, 1.5 at 3 years, and 1.6 points at 5 years. The Harris hip score improved to 38 points at 6 months, 40 points at 1 year, 38 points at 2 years, 39 points at 3 years, and 41 points at 5 years postoperatively. The improvements in the Lower-Extremity Activity Scale and the Harris hip score significantly positively correlated (p < 0.01) with the SF-6D scores at all time points. SF-6D scores

  13. Mechanical strength and hydrophobicity of cotton fabric after SF6 plasma treatment

    International Nuclear Information System (INIS)

    Kamlangkla, K.; Paosawatyanyong, B.; Pavarajarn, V.; Hodak, Jose H.; Hodak, Satreerat K.

    2010-01-01

    Surface treatments to tailor fabric properties are in high demand by the modern garment industry. We studied the effect of radio-frequency inductively coupled SF 6 plasma on the surface characteristics of cotton fabric. The duration of the treatment and the SF 6 pressure were varied systematically. We measured the hydrophobicity of treated cotton as a function of storage time and washing cycles. We used the weight loss (%) along with the etching rate, the tensile strength, the morphology changes and the hydrophobicity of the fabric as observables after treatments with different plasma conditions. The weight loss remains below 1% but it significantly increases when the treatment time is longer than 5 min. Substantial changes in the surface morphology of the fiber are concomitant with the increased etching rate and increased weight loss with measurable consequences in their mechanical characteristics. The measured water absorption time reaches the maximum of 210 min when the SF 6 pressure is higher than 0.3 Torr. The water contact angle (149 deg.) and the absorption time (210 min) of cotton treated with extreme conditions appear to be durable as long as the fabric is not washed. X-ray photoelectron spectroscopy analysis reveals that the water absorption time of the fabric follows the same increasing trend as the fluorine/carbon ratio at the fabric surface and atom density of fluorine measured by Ar actinometer.

  14. Pulse formation of gas-filled counter

    International Nuclear Information System (INIS)

    Iwatani, Kazuo; Teshima, Kazunori; Shizuma, Kiyoshi; Hasai, Hiromi

    1991-01-01

    The pulse formation of gas-filled counter has been calculated by simple models for the proportional and self-quenching streamer (SQS) modes. Calculated pulse shapes of counter output have accurately reproduced the observed ones for both modes. As a result, it is shown that the special density distribution of ion pairs in a streamer can be estimated with the rising part of observed pulse shape, using the model. (author)

  15. Time-resolved output spectrum from a hydrogen fluoride laser using mixtures of SF6 and HI

    International Nuclear Information System (INIS)

    Greiner, N.R.

    1975-01-01

    The time-resolved spectrum from a transverse-discharge hydrogen fluoride (HF) laser using a mixture of SF 6 and HI is reported. Because this spectrum matches that from a high-pressure H 2 -F 2 laser, and because the SF 6 -HI mixture is chemically stable, this laser should be a suitable and convenient source for probing H 2 -F 2 amplifiers

  16. Global distribution of mean age of stratospheric air from MIPAS SF6 measurements

    Directory of Open Access Journals (Sweden)

    H. Fischer

    2008-02-01

    Full Text Available Global distributions of profiles of sulphur hexafluoride (SF6 have been retrieved from limb emission spectra recorded by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS on Envisat covering the period September 2002 to March 2004. Individual SF6 profiles have a precision of 0.5 pptv below 25 km altitude and a vertical resolution of 4–6 km up to 35 km altitude. These data have been validated versus in situ observations obtained during balloon flights of a cryogenic whole-air sampler. For the tropical troposphere a trend of 0.230±0.008 pptv/yr has been derived from the MIPAS data, which is in excellent agreement with the trend from ground-based flask and in situ measurements from the National Oceanic and Atmospheric Administration Earth System Research Laboratory, Global Monitoring Division. For the data set currently available, based on at least three days of data per month, monthly 5° latitude mean values have a 1σ standard error of 1%. From the global SF6 distributions, global daily and monthly distributions of the apparent mean age of air are inferred by application of the tropical tropospheric trend derived from MIPAS data. The inferred mean ages are provided for the full globe up to 90° N/S, and have a 1σ standard error of 0.25 yr. They range between 0 (near the tropical tropopause and 7 years (except for situations of mesospheric intrusions and agree well with earlier observations. The seasonal variation of the mean age of stratospheric air indicates episodes of severe intrusion of mesospheric air during each Northern and Southern polar winter observed, long-lasting remnants of old, subsided polar winter air over the spring and summer poles, and a rather short period of mixing with midlatitude air and/or upward transport during fall in October/November (NH and April/May (SH, respectively, with small latitudinal gradients, immediately before the new polar vortex starts to form. The mean age distributions further

  17. Structural evolution of the P22-like phages: Comparison of Sf6 and P22 procapsid and virion architectures

    Energy Technology Data Exchange (ETDEWEB)

    Parent, Kristin N. [University of California, San Diego, Department of Chemistry and Biochemistry, La Jolla, CA 92093 (United States); Gilcrease, Eddie B. [University of Utah School of Medicine, Division of Microbiology and Immunology, Department of Pathology, Salt Lake City, UT 84112 (United States); Casjens, Sherwood R., E-mail: sherwood.casjens@path.utah.edu [University of Utah School of Medicine, Division of Microbiology and Immunology, Department of Pathology, Salt Lake City, UT 84112 (United States); Baker, Timothy S., E-mail: tsb@ucsd.edu [University of California, San Diego, Department of Chemistry and Biochemistry, La Jolla, CA 92093 (United States); University of California, San Diego, Division of Biological Sciences, La Jolla, CA 92093 (United States)

    2012-06-05

    Coat proteins of tailed, dsDNA phages and in herpesviruses include a conserved core similar to the bacteriophage HK97 subunit. This core is often embellished with other domains such as the telokin Ig-like domain of phage P22. Eighty-six P22-like phages and prophages with sequenced genomes share a similar set of virion assembly genes and, based on comparisons of twelve viral assembly proteins (structural and assembly/packaging chaperones), these phages are classified into three groups (P22-like, Sf6-like, and CUS-3-like). We used cryo-electron microscopy and 3D image reconstruction to determine the structures of Sf6 procapsids and virions ({approx} 7 A resolution), and the structure of the entire, asymmetric Sf6 virion (16-A resolution). The Sf6 coat protein is similar to that of P22 yet it has differences in the telokin domain and in its overall quaternary organization. Thermal stability and agarose gel experiments show that Sf6 virions are slightly less stable than those of P22. Finally, bacterial host outer membrane proteins A and C were identified in lipid vesicles that co-purify with Sf6 particles, but are not components of the capsid.

  18. Low pressure gas filling of laser fusion microspheres

    International Nuclear Information System (INIS)

    Koo, J.C.; Dressler, J.L.; Hendricks, C.D.

    1979-01-01

    In our laser fusion microsphere production, large, thin gel-microspheres are formed before the chemicals are fused into glass. In this transient stage,, the gel-microspheres are found to be highly permeable to argon and many other inert gases. When the gel transforms to glass, the argon gas, for example, is trapped within to form argon filled, fusion target quality, glass microspheres. On the average, the partial pressure of the argon fills attained in this process is around 2 x 10 4 Pa at room temperature

  19. Effects of SF6 plasma treatment on the properties of InGaZnO thin films

    Science.gov (United States)

    Choi, Jinsung; Bae, Byung Seong; Yun, Eui-Jung

    2018-03-01

    The effects of sulfur hexafluoride (SF6) plasma on the properties of amorphous InGaZnO (a-IGZO) thin films were examined. The properties of the a-IGZO thin films were characterized by Hall effect measurement, dynamic secondary ion mass spectroscopy (SIMS), and X-ray photoelectron spectroscopy (XPS). The IGZO thin films treated with SF6 plasma before annealing had a very high resistance mainly owing to the inclusion of S into the film surface, as evidenced by SIMS profiles. On the other hand, the samples treated with SF6 plasma after annealing showed better electrical properties with a Hall mobility of 10 cm2/(V·s) than the untreated samples or the samples SF6 plasma-treated before annealing. This was attributed to the increase in the number of oxygen vacancy defects in the a-IGZO thin films owing to the enhanced out-diffusion of O to the ambient and the increase in the number of F-related donor defects originating from the incorporation of a much larger amount of F than of S into the film surface, which were confirmed by XPS and SIMS.

  20. New gas-filled mode of the large-acceptance spectrometer VAMOS

    International Nuclear Information System (INIS)

    Schmitt, C.; Rejmund, M.; Navin, A.; Lecornu, B.; Jacquot, B.; France, G. de; Lemasson, A.; Shrivastava, A.; Greenlees, P.; Uusitalo, J.; Subotic, K.; Gaudefroy, L.; Theisen, Ch.; Sulignano, B.; Dorvaux, O.; Stuttge, L.

    2010-01-01

    A new gas-filled operation mode of the large-acceptance spectrometer VAMOS at GANIL is reported. A beam rejection factor greater than 10 10 is obtained for the 40 Ca+ 150 Sm system at 196 MeV. The unprecedented transmission efficiency for the evaporation residues produced in this reaction is estimated to be around 80% for αx n channels and above 95% for x ny p channels. A detailed study of the performance of the gas-filled VAMOS and future developments are discussed. This new operation mode opens avenues to explore the potential of fusion reactions in various kinematics.

  1. Understanding the relationship between the EQ-5D, SF-6D, HAQ and disease activity in inflammatory arthritis.

    LENUS (Irish Health Repository)

    Adams, Roisin

    2012-02-01

    BACKGROUND: The growth of economic analyses and in particular cost-utility analyses (CUA), which use the QALY as a measure of outcome, has heightened the interest in the methodologies used to calculate the QALY. The EQ-5D has produced quite different utility values from that of the SF-6D. This article seeks to understand these differences using a cohort of patients with inflammatory arthritis. OBJECTIVE: To examine the relationship between the disease-specific measure, Health Assessment Questionnaire (HAQ) disability index (DI) and the preference-based measures, SF-6D, EQ-5D and European League Against Arthritis (EULAR) Disease Activity Score (DAS) in patients with rheumatoid arthritis (RA) and psoriatic arthritis (PsA). METHODS: Patients with RA and PsA (n = 504) attending a tertiary rheumatology referral centre completed the HAQ, SF-6D and the EQ-5D before starting biological therapy and again 12 months later. The SF-36 was converted into a utility using the preference-based SF-6D. Clinical outcomes such as the DAS, joint counts and laboratory measures were also recorded. We calculated single index utility scores from the preference-based instruments using UK population norms. We used regression analysis to derive a mapping function and calculated utility scores from the HAQDI and the DAS 28. RESULTS: The mean utility observed at baseline for RA was 0.43 for the EQ-5D and 0.54 for the SF-6D and for PsA was 0.49 for the EQ-5D and 0.57 for the SF-6D. The utility gain demonstrated by the EQ-5D was over twice that of the SF-6D. The EQ-5D scored 17% of the RA group as less than 0 (state defined as worse than death); 7% of this group remained less than 0 at follow-up. The distribution of the utility estimates was similar for both RA and PsA. CONCLUSIONS: Our findings draw attention to the impact of states worse than death on the overall distribution for the EQ-5D derived utilities and how these impact on its use in practice. EQ-5D-derived QALY changes are over twice

  2. Measurement of the odor impact of a waste deposit using the SF6-tracer method

    International Nuclear Information System (INIS)

    Roetzer, H.; Muehldorf, V.; Riesing, J.

    1994-12-01

    Landfill gas emitted from a waste deposit often causes odor nuisance in the vicinity. For a new sanitary landfill to be established in an area where also other sources of odor existed, very low limits for additional odor nuisance were given by local authorities. To verify that the odor concentrations were below these limit values, the odor contributions of different sources had to be distinguished. Olfactometric methods, using human observers to estimate the intensity of odors, were not applicable to this problem. For direct measurements by analytical methods concentrations of odorous substances were too small. Therefore a tracer method was applied to measure the odor impact of the sanitary landfill to its environment. The emitted landfill gas was labelled with the tracer gas SF 6 . The tracer gas was parted to even amounts and released through ten special nozzles equally distributed over the surface of the landfill. In the area around the landfill the concentration of the tracer gas was measured by collecting air samples and analysing them with a gas chromatograph with an electron capture detector. Fifteen air sampling units were used to collect eight consecutive air samples at each selected point. These measurements gave the relation between the emission of landfill gas and the resulting concentrations in ambient air. With these transmission coefficients the concentrations of odorous gases at the sampling points were evaluated, using the emission concentrations measured by analytical techniques at the landfiIl site. The resulting odor concentrations were compared with values of odor thresholds to establish the odor impact of the waste deposit on the environment. (author)

  3. Electron attachment to the SF{sub 6} molecule

    Energy Technology Data Exchange (ETDEWEB)

    Smirnov, B. M., E-mail: bmsmirnov@gmail.com; Kosarim, A. V. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    2015-09-15

    Various models for transition between electron and nuclear subsystems are compared in the case of electron attachment to the SF{sub 6} molecule. Experimental data, including the cross section of electron attachment to this molecule as a function of the electron energy and vibrational temperature, the rate constants of this process in swarm experiments, and the rates of the chemionization process involving Rydberg atoms and the SF{sub 6} molecule, are collected and treated. Based on the data and on the resonant character of electron capture into an autodetachment ion state in accordance with the Breit–Wigner formula, we find that intersection of the molecule and negative ion electron terms proceeds above the potential well bottom of the molecule with the barrier height 0.05–0.1 eV, and the transition between these electron terms has both the tunnel and abovebarrier character. The limit of small electron energies e for the electron attachment cross section at room vibrational temperature takes place at ε ≪ 2 meV, while in the range 2 meV ≪ ε ≪ 80 meV, the cross section is inversely proportional to ε. In considering the attachment process as a result of the interaction between the electron and vibrational degrees of freedom, we find the coupling factor f between them to be f = aT at low vibrational temperatures T with a ≈ 3 × 10{sup −4} K{sup −1}. The coupling factor is independent of the temperature at T > 400 K.

  4. Inventory compilation of F-gases 2008. Data on HFCs, PFCs, and SF{sub 6} for the national emissions reporting under the Framework Convention on Climate Change for the reporting year 2008; Emissionen fluorierter Treibhausgase in Deutschland 2008. Inventarermittlung der F-Gase 2008 Daten von HFKW, FKW und SF6 fuer die nationale Emissionsberichterstattung gemaess Klimarahmenkonvnention fuer das Berichtsjahr 2008

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, Winfried [Oeko-Recherche Buero fuer Umweltforschung und -beratung GmbH, Frankfurt/Main (Germany)

    2010-06-15

    This report presents the 2008 data on the German emissions of the fluorinated greenhouse gases HFCs, PFCs, and SF{sub 6} (F-gases) to be entered into the ZSE (Centralised System of Emissions at the German Environmental Agency). The overall emissions of HFCs, PFCs, and SF6 have doubled from 1995 to 2008, from 3,241 to 7,202 metric tons. In terms of global warming, the emissions in 2008 exceeded again the 1995 level, with 18.0 vs. 15.5 million tons CO{sub 2} equivalent. Against the previous your, the emissions in metric units have decreased the first time since 1995, however the global warming emissions, have increased by further 0.7 million t CO{sub 2} equivalent. PFC emissions remained in 2008 at the 2007 level although they show a constant down trend from 1995 onwards. Emissions of SF6, which had decreased before 2002, are increasing again from 2003/04. HFC emissions, which continue rising since 1995, stopped growing in 2008 due to a consumption drop in the foam sector. They represent almost two thirds of the total German F-gas emissions. However, only refrigeration and air conditioning are still substantial applications of HFCs, while in the formerly large application sectors of CFCs and HCFCs, such as hard foam, fire extinguishers, and aerosols, natural fluids are being used widely, today. In stationary refrigeration and mobile air conditioning, the upward trend in HFCs emissions was still ongoing in 2008. Section I of this report presents the F-gas emissions data for 2008, in addition to those in 1995, 2000, 2004, and 2007. In section II the data sources of survey are documented. Section III presents the F-gas emissions 1995 - 2008 in detailed tables, by individual sectors. (orig.)

  5. Use of argon to measure gas exchange in turbulent mountain streams

    Science.gov (United States)

    Hall, Robert O., Jr.; Madinger, Hilary L.

    2018-05-01

    Gas exchange is a parameter needed in stream metabolism and trace gas emissions models. One way to estimate gas exchange is via measuring the decline of added tracer gases such as sulfur hexafluoride (SF6). Estimates of oxygen (O2) gas exchange derived from SF6 additions require scaling via Schmidt number (Sc) ratio, but this scaling is uncertain under conditions of high gas exchange via bubbles because scaling depends on gas solubility as well as Sc. Because argon (Ar) and O2 have nearly identical Schmidt numbers and solubility, Ar may be a useful tracer gas for estimating stream O2 exchange. Here we compared rates of gas exchange measured via Ar and SF6 for turbulent mountain streams in Wyoming, USA. We measured Ar as the ratio of Ar : N2 using a membrane inlet mass spectrometer (MIMS). Normalizing to N2 confers higher precision than simply measuring [Ar] alone. We consistently enriched streams with Ar from 1 to 18 % of ambient Ar concentration and could estimate gas exchange rate using an exponential decline model. The mean ratio of gas exchange of Ar relative to SF6 was 1.8 (credible interval 1.1 to 2.5) compared to the theoretical estimate 1.35, showing that using SF6 would have underestimated exchange of Ar. Steep streams (slopes 11-12 %) had high rates of gas exchange velocity normalized to Sc = 600 (k600, 57-210 m d-1), and slope strongly predicted variation in k600 among all streams. We suggest that Ar is a useful tracer because it is easily measured, requires no scaling assumptions to estimate rates of O2 exchange, and is not an intense greenhouse gas as is SF6. We caution that scaling from rates of either Ar or SF6 gas exchange to CO2 is uncertain due to solubility effects in conditions of bubble-mediated gas transfer.

  6. Validation and comparison of EuroQoL-5 dimension (EQ-5D) and Short Form-6 dimension (SF-6D) among stable angina patients.

    Science.gov (United States)

    Wu, Jing; Han, Yuerong; Zhao, Fei-Li; Zhou, Jin; Chen, Zhijun; Sun, He

    2014-10-25

    Several preference-based health-related quality of life (HRQoL) instruments have been published and widely used in different populations. However no consensus has emerged regarding the most appropriate instrument in therapeutic area of stable angina. This study compared and validated the psychometric properties of two generic preference-based instruments, the EQ-5D and SF-6D, among Chinese stable angina patients. Convergent validity of the EQ-5D and SF-6D was examined with eight a priori hypotheses from stable angina patients in conjunction with Seattle Angina Questionnaire (SAQ). Responsiveness was compared using the effect size (ES), relative efficiency (RE) and receiver operating characteristic (ROC) curves. Agreement between the EQ-5D and SF-6D was tested using intra-class correlation coefficient (ICC) and Bland-Altman plot. Factors affecting utility difference were explored with multiple linear regression analysis. In 411 patients (mean age 68.08 ± 11.35), mean utility scores (SD) were 0.78 (0.15) for the EQ-5D and 0.68 (0.12) for the SF-6D. Validity was demonstrated by the moderate to strong correlation coefficients (Range: 0.368-0.594, Pstable-angina-specific health status than the EQ-5D (ES: 0.426 to 1.126). RE suggested that the SF-6D (RE: 44.8 to 177.8%) was more efficient than the EQ-5D except for physical function. Poor agreement between them was observed with ICC (0.448, Pstable angina patients. The SF-6D may be a more effective tool with lower ceiling effect and greater sensitivity. Further study is needed to compare other properties, such as reliability and longitudinal response.

  7. Buoyancy of gas-filled bladders at great depth

    Science.gov (United States)

    Priede, Imants G.

    2018-02-01

    At high hydrostatic pressures exceeding 20 MPa or 200 bar, equivalent to depths exceeding ca.2000 m, the behaviour of gases deviates significantly from the predictions of standard equations such as Boyle's Law, the Ideal Gas Law and Van der Waals equation. The predictions of these equations are compared with experimental data for nitrogen, oxygen and air at 0 °C and 15 °C, at pressures up to 1100 bar (110 MPa) equivalent to full ocean depth of ca. 11000 m. Owing to reduced compressibility of gases at high pressures, gas-filled bladders at full ocean depth have a density of 847 kg m-3 for Oxygen, 622 kg m-3 for Nitrogen and 660 kg m-3 for air providing potentially useful buoyancy comparable with that available from man-made materials. This helps explain why some of the deepest-living fishes at ca. 7000 m depth (700 bar or 70 MPa) have gas-filled swim bladders. A table is provided of the density and buoyancy of oxygen, nitrogen and air at 0 °C and 15 °C from 100 to 1100 bar.

  8. Function and horizontal transfer of the small terminase subunit of the tailed bacteriophage Sf6 DNA packaging nanomotor

    Science.gov (United States)

    Leavitt, Justin C.; Gilcrease, Eddie B.; Wilson, Kassandra; Casjens, Sherwood R.

    2013-01-01

    Bacteriophage Sf6 DNA packaging series initiate at many locations across a 2 kbp region. Our in vivo studies that show that Sf6 small terminase subunit (TerS) protein recognizes a specific packaging (pac) site near the center of this region, that this site lies within the portion of the Sf6 gene that encodes the DNA-binding domain of TerS protein, that this domain of the TerS protein is responsible for the imprecision in Sf6 packaging initiation, and that the DNA-binding domain of TerS must be covalently attached to the domain that interacts with the rest of the packaging motor. The TerS DNA-binding domain is self-contained in that it apparently does not interact closely with the rest of the motor and it binds to a recognition site that lies within the DNA that encodes the domain. This arrangement has allowed the horizontal exchange of terS genes among phages to be very successful. PMID:23562538

  9. Does the Bush Administration's climate policy mean climate protection?

    International Nuclear Information System (INIS)

    Blanchard, Odile; Perkaus, James F.

    2004-01-01

    The paper analyzes the two major components of the Bush Administration's climate policy, namely an emission intensity target and a technology strategy. The question is whether those components will generate net emission reductions that will contribute to the stabilization of the greenhouse gas concentration at a safe level in the long run. It comes out that the Bush Administration climate policy does not guarantee any meaningful contribution to climate protection. The lenient emission intensity target set by the Administration will most likely allow near term emissions to grow. In the long run, the Bush Administration places a big bet on future climate-friendly technological breakthroughs to cost-effectively compensate for the current and near term net emission increases. But the outcomes of those technological developments are uncertain in terms of emission reduction potential, cost, and timing. The way towards enhanced climate protection will most likely not come from the policies of the current Administration, but rather from the growing concern about the climate issue in Congress and at the state, corporate and civil society levels. These combined forces may raise the playing field at the federal level in the near future

  10. Numaerical simulation of a SF6 circuit-breaker arc

    International Nuclear Information System (INIS)

    Vergne, P.J.; Gonzalez, J.J.; Gleizes, A.

    1995-01-01

    The design and the validation of high-voltage circuit breaker require more and more physical models which take into account complex phenomenae. We present here a numerical simulation of an SF 6 arc established in a simplified geometry of a circuit breaker prototype. Our study deals specially with the turbulent flow, the boundary conditions of the arc roots on the electrodes, the influence of the electromagnetic strengths and the radiative transfer. The results concern a stationary state with fixed geometry and current intensity (I=2000 A)

  11. Mechanical strength and hydrophobicity of cotton fabric after SF{sub 6} plasma treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kamlangkla, K. [Nanoscience and Nanotechnology Program, Center of Innovative Nanotechnology, Chulalongkorn University, Bangkok 10330 (Thailand); Paosawatyanyong, B. [Department of Physics, Faculty of Science, Chulalongkorn University, and ThEP Center, Commission on Higher Education, Bangkok 10330 (Thailand); Pavarajarn, V. [Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330 (Thailand); Hodak, Jose H. [Department of Physics, Faculty of Science, Mahidol University, Bangkok 10400 (Thailand); Hodak, Satreerat K., E-mail: Satreerat.H@Chula.ac.th [Department of Physics, Faculty of Science, Chulalongkorn University, and ThEP Center, Commission on Higher Education, Bangkok 10330 (Thailand)

    2010-08-01

    Surface treatments to tailor fabric properties are in high demand by the modern garment industry. We studied the effect of radio-frequency inductively coupled SF{sub 6} plasma on the surface characteristics of cotton fabric. The duration of the treatment and the SF{sub 6} pressure were varied systematically. We measured the hydrophobicity of treated cotton as a function of storage time and washing cycles. We used the weight loss (%) along with the etching rate, the tensile strength, the morphology changes and the hydrophobicity of the fabric as observables after treatments with different plasma conditions. The weight loss remains below 1% but it significantly increases when the treatment time is longer than 5 min. Substantial changes in the surface morphology of the fiber are concomitant with the increased etching rate and increased weight loss with measurable consequences in their mechanical characteristics. The measured water absorption time reaches the maximum of 210 min when the SF{sub 6} pressure is higher than 0.3 Torr. The water contact angle (149 deg.) and the absorption time (210 min) of cotton treated with extreme conditions appear to be durable as long as the fabric is not washed. X-ray photoelectron spectroscopy analysis reveals that the water absorption time of the fabric follows the same increasing trend as the fluorine/carbon ratio at the fabric surface and atom density of fluorine measured by Ar actinometer.

  12. Posterior subtenon triamcinolone acetonide in gas-filled eyes as an adjunctive treatment for complicated proliferative diabetic retinopathy.

    Science.gov (United States)

    Lee, Yongeun; Kang, Seungbum; Park, Young-Hoon

    2013-02-01

    To evaluate the effect of adjunctive subtenon injection of triamcinolone acetonide (TA) in gas-filled eyes after vitrectomy for complicated proliferative diabetic retinopathy (PDR). This nonrandomized comparative study included 27 patients (27 eyes) who underwent pars plana vitrectomy and gas tamponade for treatment of PDR with tractional or combined tractional-rhegmatogenous retinal detachment and who received subtenon injection of TA (40 mg) at the end of surgery. The study group was compared with the control group (29 eyes), which was matched with the study group for preoperative and intraoperative parameters, but underwent pars plana vitrectomy and gas tamponade without a subtenon injection of TA. Retinal reattachments without reoperation were achieved in 25 eyes (92.6%) and 26 eyes (89.7%) at 6 months (p = 1.000) in the study and control groups, respectively. The study group and the control group did not differ significantly in the frequency of postoperative proliferative vitreoretinopathy, retinal redetachment rate, reoperation rate, macular pucker formation, postoperative vitreous hemorrhage, gain in visual acuity, intraocular pressure, and intraocular inflammation (p > 0.05). The clinical results of pars plana vitrectomy for complicated PDR are not improved significantly by an adjunctive subtenon TA injection in gas-filled eyes.

  13. On-line system on the base of the ELEKTRONIKA D3-28 microcomputer for gas filling

    International Nuclear Information System (INIS)

    Artemov, A.A.; Baranchuk, N.S.; Livitskij, M.M.; Platonov, V.P.; Chernyak, V.Ya.

    1989-01-01

    On-line system for gas filling on the base of SNA-1 pressure controller, ELEKTRONIKA D3-28 microcomputer and interface device and program for information exchange within the system are described. The system is designed for on-line measurement of gas pressure and filling and is used during operation without pumping out. Volume of vacuum chamber is 0.8 m 3 , pressure of filled-out gas (nitrogen) is 1 atm. The system enables to change pressure up to 0.1 Torr with 1x10 -4 Torr accuracy. Actuation time of g as filling-on system is determined with program control and depends on pressure measurement. Minimal actuation time of gas filling-on system is determined with program control and depends on pressure measurement. Minimal actuation time is 12 ms

  14. Environmental geophysics at the Southern Bush River Peninsula, Aberdeen Proving Ground, Maryland

    Energy Technology Data Exchange (ETDEWEB)

    Davies, B.E.; Miller, S.F.; McGinnis, L.D. [and others

    1995-05-01

    Geophysical studies have been conducted at five sites in the southern Bush River Peninsula in the Edgewood Area of Aberdeen Proving Ground, Maryland. The goals of the studies were to identify areas containing buried metallic objects and to provide diagnostic signatures of the hydrogeologic framework of the site. These studies indicate that, during the Pleistocene Epoch, alternating stands of high and low sea level resulted in a complex pattern of channel-fill deposits. Paleochannels of various sizes and orientations have been mapped throughout the study area by means of ground-penetrating radar and EM-31 techniques. The EM-31 paleochannel signatures are represented onshore either by conductivity highs or lows, depending on the depths and facies of the fill sequences. A companion study shows the features as conductivity highs where they extend offshore. This erosional and depositional system is environmentally significant because of the role it plays in the shallow groundwater flow regime beneath the site. Magnetic and electromagnetic anomalies outline surficial and buried debris throughout the areas surveyed. On the basis of geophysical measurements, large-scale (i.e., tens of feet) landfilling has not been found in the southern Bush River Peninsula, though smaller-scale dumping of metallic debris and/or munitions cannot be ruled out.

  15. Substitutes for potent green house gases. HFCs, PFCs and SF{sub 6}. Status report

    Energy Technology Data Exchange (ETDEWEB)

    Pedersen, P.H. [Dansk Teknologisk Institut (Denmark)

    1997-12-31

    CFCs (halogenated chlorofluorocarbons), HCFCs (hydrochlorofluorocarbons), HFCs (hydrofluorocarbons), PFCs (fluorocarbons) and SF{sub 6} (sulphur hexafluoride) are all artificial substances which were not to be found in nature until recently. In 1995 the Danish consumption of HFC substances was approximately 740 tonnes, where the corresponding amount of SF{sub 6} was about 17 tonnes. If the entire amount of these substances was released to to the atmosphere, the resulting impact would correspond to an increased emission of greenhouse gases, corresponding to approximately 1.5 million tonnes of CO{sub 2}. HFC substances would account for 73%, SF{sub 6} with 25% and PFC for 1%. This corresponds to approximately 2.6% of the Danish CO{sub 2} emission (nearly 60 million tonnes per year). This corresponds to about half of the aimed 6% reduction of CO{sub 2} emission attained by introduction of mandatory green taxes on CO{sub 2}. According to experience from the CFC programme it is possible to recover some CFC and send it to controlled destruction. From 1993 to 1996 the refrigeration industry, for instance, has returned a total amount of 163 tonnes of CFC refrigerant through the KMO organization (Koelebranchens Miljoe Ordning). Most of this has been destroyed and a small amount has been purified and recycled afterwards. Similarly, it is likely to believe that some HFC refrigerant will be returned through the KMO organization. (au) 11 refs., also published in Danish

  16. Evaluation of stratospheric age of air from CF4, C2F6, C3F8, CHF3, HFC-125, HFC-227ea and SF6; implications for the calculations of halocarbon lifetimes, fractional release factors and ozone depletion potentials

    Science.gov (United States)

    Leedham Elvidge, Emma; Bönisch, Harald; Brenninkmeijer, Carl A. M.; Engel, Andreas; Fraser, Paul J.; Gallacher, Eileen; Langenfelds, Ray; Mühle, Jens; Oram, David E.; Ray, Eric A.; Ridley, Anna R.; Röckmann, Thomas; Sturges, William T.; Weiss, Ray F.; Laube, Johannes C.

    2018-03-01

    In a changing climate, potential stratospheric circulation changes require long-term monitoring. Stratospheric trace gas measurements are often used as a proxy for stratospheric circulation changes via the mean age of air values derived from them. In this study, we investigated five potential age of air tracers - the perfluorocarbons CF4, C2F6 and C3F8 and the hydrofluorocarbons CHF3 (HFC-23) and HFC-125 - and compare them to the traditional tracer SF6 and a (relatively) shorter-lived species, HFC-227ea. A detailed uncertainty analysis was performed on mean ages derived from these new tracers to allow us to confidently compare their efficacy as age tracers to the existing tracer, SF6. Our results showed that uncertainties associated with the mean age derived from these new age tracers are similar to those derived from SF6, suggesting that these alternative compounds are suitable in this respect for use as age tracers. Independent verification of the suitability of these age tracers is provided by a comparison between samples analysed at the University of East Anglia and the Scripps Institution of Oceanography. All five tracers give younger mean ages than SF6, a discrepancy that increases with increasing mean age. Our findings qualitatively support recent work that suggests that the stratospheric lifetime of SF6 is significantly less than the previous estimate of 3200 years. The impact of these younger mean ages on three policy-relevant parameters - stratospheric lifetimes, fractional release factors (FRFs) and ozone depletion potentials - is investigated in combination with a recently improved methodology to calculate FRFs. Updates to previous estimations for these parameters are provided.

  17. Air Versus Sulfur Hexafluoride Gas Tamponade in Descemet Membrane Endothelial Keratoplasty: A Fellow Eye Comparison.

    Science.gov (United States)

    von Marchtaler, Philipp V; Weller, Julia M; Kruse, Friedrich E; Tourtas, Theofilos

    2018-01-01

    To perform a fellow eye comparison of outcomes and complications when using air or sulfur hexafluoride (SF6) gas as a tamponade in Descemet membrane endothelial keratoplasty (DMEK). One hundred thirty-six eyes of 68 consecutive patients who underwent uneventful DMEK in both eyes for Fuchs endothelial corneal dystrophy were included in this retrospective study. Inclusion criteria were air tamponade (80% of the anterior chamber volume) in the first eye and 20% SF6 gas tamponade (80% of the anterior chamber volume) in the second eye; and same donor tissue culture condition in both eyes. All eyes received laser iridotomy on the day before DMEK. Main outcome measures included preoperative and postoperative best-corrected visual acuity, endothelial cell density, corneal volume, rebubbling rate, and rate of postoperative pupillary block caused by the air/gas bubble. Thirteen of 68 eyes (19.1%) with an air tamponade needed rebubbling compared with 4 of 68 eyes (5.9%) with an SF6 gas tamponade (P = 0.036). Postoperative pupillary block necessitating partial release of air/gas occurred in 1 eye (1.5%) with an air tamponade and 3 eyes (4.4%) with an SF6 gas tamponade (P = 0.301). There were no significant differences in preoperative and postoperative best-corrected visual acuity, endothelial cell density, and corneal volume within 3-month follow-up. Our results confirm the previously reported better graft adhesion when using an SF6 gas tamponade in DMEK without increased endothelial cell toxicity. The rate of pupillary block in eyes with an SF6 gas tamponade was comparable to that with an air tamponade. As a consequence, we recommend using SF6 gas as the tamponade in DMEK.

  18. The greenhouse gases HFCs, PFCs and SF{sub 6}, Danish consumption and emissions, 2007

    Energy Technology Data Exchange (ETDEWEB)

    Sander Poulsen, T.; Bode, I.

    2009-07-01

    The objective of this project was to determine the Danish consumption and actual emissions of HFCs, PFCs, and SF{sub 6} for 2007. Further, if methodology changes are made in connection to the work on 2007 data, the data for previous years are considered and updated accordingly. The emission calculation is made in accordance with the IPCC guidelines and following the method employed in previous year calculation. The methodology includes calculation of the actual emissions of HFCs, PFCs, and SF{sub 6}. In this calculation of actual emissions, the release from stock of greenhouse gases in products has been taken into account, and adjustments have been made for imports and exports of the greenhouse gases in products. Specific emission factors are presented. (ln)

  19. Improvement in the heat transfer of a gas filled thermal switch

    International Nuclear Information System (INIS)

    Yamamoto, J.

    1984-01-01

    This chapter attempts to clarify the heat transfer mechanism of a gas filled stainless steel tube, and shows how the maximum heat transfer rate is determined under various filling pressures. The thermal switch is a convenient device for a thermal link between the cold heat of a cryocooler and a magnet dewar, because the switch acts as an active thermal conductor at the precooling stage and as an insulator after collecting liquid helium in the dewar. Topics considered include the switch structure, the heat transfer process, the delay of condensation, and the precooling stage and switching. It is determined that the heat transfer mechanism of the gas filled switch is due to normal nucleate boiling at the bottom and condensation on the upper cone. The higher the initial pressure, the larger the maximum heat flow obtained. Evaporation and condensation surfaces play an important role in the heat transfer rate

  20. Multiple soliton compression stages in mid-IR gas-filled hollow-core fibers

    DEFF Research Database (Denmark)

    Habib, Md Selim; Markos, Christos; Bang, Ole

    2017-01-01

    The light confinement inside hollow-core (HC) fibers filled with noble gases constitutes an efficient route to study interesting soliton-plasma dynamics [1]. More recently, plasma-induced soliton splitting at the self-compression point was observed in a gas-filled fiber in the near-IR [2]. However...

  1. Comparison of Two Potassium-Filled Gas-Controlled Heat Pipes

    Science.gov (United States)

    Bertiglia, F.; Iacomini, L.; Moro, F.; Merlone, A.

    2015-12-01

    Calibration by comparison of platinum resistance thermometers and thermocouples requires transfer media capable of providing very good short-term temperature uniformity and temperature stability over a wide temperature range. This paper describes and compares the performance of two potassium-filled gas-controlled heat pipes (GCHP) for operation over the range from 420° C to 900° C. One of the heat pipes has been in operation for more than 10 years having been operated at temperature for thousands of hours, while the other was commissioned in 2010 following recently developed improvements to both the design, assembly, and filling processes. It was found that the two devices, despite differences in age, structure, number of wells, and filling processes, realized the same temperatures within the measurement uncertainty. The results show that the potassium-filled GCHP provides a durable and high-quality transfer medium for performing thermometer calibrations with very low uncertainties, over the difficult high-temperature range from 420° C to 900° C.

  2. The relationship between SF-6D utility scores and lifestyle factors across three life stages: evidence from the Australian Longitudinal Study on Women's Health.

    Science.gov (United States)

    Kanesarajah, Jeeva; Waller, Michael; Whitty, Jennifer A; Mishra, Gita D

    2017-06-01

    To investigate how SF-6D utility scores change with age between generations of women and to quantify the relationship of SF-6D with lifestyle factors across life stages. Up to seven waves of self-reported, longitudinal data were drawn for the 1973-1978 (young, N = 13772), 1946-1951 (mid-age, N = 12792), 1921-1926 (older, N = 9972) cohorts from the Australian Longitudinal Study on Women's Health. Mixed effects models were employed for analysis. Young and mid-age women had similar average SF-6D scores at baseline (0.63-0.64), which remained consistent over the 16-year period. However, older women had lower scores at baseline at 0.57 which steadily declined over 15 years. Across cohorts, low education attainment, greater difficulty in managing income, obesity, physical inactivity, heavy smoking, no alcohol consumption, and increasing stress levels were associated with lower SF-6D scores. The magnitude of effect varied between cohorts. SF-6D scores were lower amongst young women with high-risk drinking behaviours than low-risk drinkers. Mid-age women, who were underweight, never married, or underwent surgical menopause also reported lower SF-6D scores. Older women who lived in remote areas, who were ex-smokers, or were underweight, reported lower SF-6D scores. The SF-6D utility score is sensitive to differences in lifestyle factors across adult life stages. Gradual loss of physical functioning may explain the steady decline in health for older women. Key factors associated with SF-6D include physical activity, body mass index, menopause status, smoking, alcohol use, and stress. Factors associated with poorer SF-6D scores vary in type and magnitude at different life stages.

  3. Radionuclide analysis of bush food

    International Nuclear Information System (INIS)

    Koperski, J.; Bywater, J.

    1985-01-01

    A model diet for an Aboriginal adult living entirely on bush foods collected from the Alligator Rivers Region of the Northern Territory has been established. Results of investigations of the specific activities of thorium-230, radium-226, lead-210 and polonium-210 in 123 samples of bush foods collected by Ranger Uranium Mines Pty Ltd during pre-production and production periods are presented. For all the investigated bush food items, excluding freshwater mussels (Velesunio angasi), no systematic differences were found between the specific activities of the radionuclides monitored in food items sampled during preproduction and production periods. Preliminary estimates of annual effective dose equivalent (DE) rates for stochastic effects on an adult living entirely on the model bush diet are presented. Of the four radionuclides monitored the major contributor to the effective DE rates appears to be lead-210 followed by radium-226. Among the selected nine components of the diet the major contributor to the effective DE rates appear to be mussels, water lilies and fish

  4. Radionuclide analysis of bush food

    Energy Technology Data Exchange (ETDEWEB)

    Koperski, J; Bywater, J [Ranger Uranium Mines Proprietary Ltd., Chatswood (Australia)

    1985-04-01

    A model diet for an Aboriginal adult living entirely on bush foods collected from the Alligator Rivers Region of the Northern Territory has been established. Results of investigations of the specific activities of thorium-230, radium-226, lead-210 and polonium-210 in 123 samples of bush foods collected by Ranger Uranium Mines Pty. Ltd. during pre-production and production periods are presented. For all the investigated bush food items, excluding freshwater mussels (Velesunio angasi), no systematic differences were found between the specific activities of the radionuclides monitored in food items sampled during preproduction and production periods. Preliminary estimates of annual effective dose equivalent (DE) rates for stochastic effects on an adult living entirely on the model bush diet are presented. Of the four radionuclides monitored the major contributor to the effective DE rates appears to be lead-210 followed by radium-226. Among the selected nine components of the diet the major contributor to the effective DE rates appear to be mussels, water lilies and fish.

  5. Inactivation of Tm6sf2, a Gene Defective in Fatty Liver Disease, Impairs Lipidation but Not Secretion of Very Low Density Lipoproteins.

    Science.gov (United States)

    Smagris, Eriks; Gilyard, Shenise; BasuRay, Soumik; Cohen, Jonathan C; Hobbs, Helen H

    2016-05-13

    A missense mutation (E167K) in TM6SF2 (transmembrane 6 superfamily member 2), a polytopic protein of unknown function, is associated with the full spectrum of fatty liver disease. To investigate the role of TM6SF2 in hepatic triglyceride (TG) metabolism, we inactivated the gene in mice. Chronic inactivation of Tm6sf2 in mice is associated with hepatic steatosis, hypocholesterolemia, and transaminitis, thus recapitulating the phenotype observed in humans. No dietary challenge was required to elicit the phenotype. Immunocytochemical and cell fractionation studies revealed that TM6SF2 was present in the endoplasmic reticulum and Golgi complex, whereas the excess neutral lipids in the Tm6sf2(-/-) mice were located in lipid droplets. Plasma VLDL-TG levels were reduced in the KO animals due to a 3-fold decrease in VLDL-TG secretion rate without any associated reduction in hepatic apoB secretion. Both VLDL particle size and plasma cholesterol levels were significantly reduced in KO mice. Despite levels of TM6SF2 protein being 10-fold higher in the small intestine than in the liver, dietary lipid absorption was only modestly reduced in the KO mice. Our data, taken together, reveal that TM6SF2 is required to mobilize neutral lipids for VLDL assembly but is not required for secretion of apoB-containing lipoproteins. Despite TM6SF2 being located in the endoplasmic reticulum and Golgi complex, the lipids that accumulate in its absence reside in lipid droplets. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  6. Improving methane gas sensing properties of multi-walled carbonnanotubes by vanadium oxide filling

    CSIR Research Space (South Africa)

    Chimowa, George

    2017-08-01

    Full Text Available Manipulation of electrical properties and hence gas sensing properties of multi-walled carbon nanotubes (MWNTs) by filling the inner wall with vanadium oxide is presented. Using a simple capillary technique, MWNTs are filled with vanadium metal...

  7. Instrument for detecting gas bubbles in sodium filled pipework

    Energy Technology Data Exchange (ETDEWEB)

    Stapleton, D

    1973-08-01

    An instrument employing an electromagnetic sensor is described. Gas bubbles down to 0.5 mm diameter can be detected in sodium filled pipework of 1 in. nominal bore at temperatures up to 400 deg C. Installation of the sensing head involves no break in the integrity of the pipework. Facilities to enable bubble size discrimination, bubble counting and timing pulse generation are provided in the signal processing unit. Initial operating experience has been gained on a sodium loop used for gas entrainment studies. (auth)

  8. Validation and comparison of EuroQoL-5 dimension (EQ-5D) and Short Form-6 dimension (SF-6D) among stable angina patients

    OpenAIRE

    Wu, Jing; Han, Yuerong; Zhao, Fei-Li; Zhou, Jin; Chen, Zhijun; Sun, He

    2014-01-01

    Objectives Several preference-based health-related quality of life (HRQoL) instruments have been published and widely used in different populations. However no consensus has emerged regarding the most appropriate instrument in therapeutic area of stable angina. This study compared and validated the psychometric properties of two generic preference-based instruments, the EQ-5D and SF-6D, among Chinese stable angina patients. Methods Convergent validity of the EQ-5D and SF-6D was examined with ...

  9. 48 CFR 53.301-18 - SF 18 (Rev. 6/95), Request for Quotations.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false SF 18 (Rev. 6/95), Request for Quotations. 53.301-18 Section 53.301-18 Federal Acquisition Regulations System FEDERAL ACQUISITION... for Quotations. EC01MY91.002 [60 FR 34763, July 3, 1995] ...

  10. Pressure regulation system for modern gas-filled detectors

    International Nuclear Information System (INIS)

    McDonald, R.J.

    1986-08-01

    A gas pressure and flow regulation system has been designed and constructed to service a wide variety of gas-filled detectors which operate at pressures of ∼2 to 1000 Torr and flow rate of ∼5 to 200 standard cubic centimeters per minute (sccm). Pressure regulation is done at the detector input by a pressure transducer linked to a solenoid leak valve via an electronic control system. Gas flow is controlled via a mechanical leak valve at the detector output. Interchangeable transducers, flowmeters, and leak valves allow for different pressure and flow ranges. The differential pressure transducer and control system provide automatic let-up of vacuum chambers to atmospheric pressure while maintaining a controlled overpressure in the detector. The gas system is constructed on a standard 19'' rack-mounted panel from commercially available parts. Five of these systems have been built and are routinely used for both ionization chambers and position-sensitive avalanche detectors

  11. X-ray detector for automatic exposure control using ionization chamber filled with xenon gas

    CERN Document Server

    Nakagawa, A; Yoshida, T

    2003-01-01

    This report refers to our newly developed X-ray detector for reliable automatic X-ray exposure control, which is to be widely used for X-ray diagnoses in various clinical fields. This new detector utilizes an ionization chamber filled with xenon gas, in contrast to conventional X-ray detectors which use ionization chambers filled with air. Use of xenon gas ensures higher sensitivity and thinner design of the detector. The xenon gas is completely sealed in the chamber, so that the influence of the changes in ambient environments is minimized. (author)

  12. Modeling of filling gas centrifuge cascade for nickel isotope separation by feed flow input to different stages

    Directory of Open Access Journals (Sweden)

    Orlov Alexey A.

    2017-01-01

    Full Text Available The article presents results of research filling gas centrifuge cascade by process gas fed into different stages. The modeling of filling cascade was done for nickel isotope separation. Analysis of the research results shows that nickel isotope concentrations of light and heavy fraction flows after filling cascade depend on feed stage number.

  13. Quantifying Reaeration Rates in Alpine Streams Using Deliberate Gas Tracer Experiments

    Directory of Open Access Journals (Sweden)

    Andrew Benson

    2014-04-01

    Full Text Available Gas exchange across the air-water interface is a critical process that maintains adequate dissolved oxygen (DO in the water column to support life. Oxygen reaeration rates can be accurately measured using deliberate gas tracers, like sulfur hexafluoride (SF6 or xenon (Xe. Two continuous release experiments were conducted in different creeks in the Sierra Nevada of California: Sagehen Creek in September, 2009, using SF6 and Martis Creek in August, 2012, using both SF6 and Xe. Measuring gas loss along the creek, which was approximated with the one-dimensional advection-dispersion equation, allows for the estimation of the SF6 or Xe reaeration coefficient (KSF6, KXe, which is converted to DO reaeration (KDO or K2 using Schmidt numbers. Mean KSF6 for upper and lower Sagehen and Martis Creeks were, respectively, 34 day−1, 37 day−1 and 33 day−1, with corresponding KDOs of 61 day−1, 66 day−1 and 47 day−1. In Martis Creek, KXe was slightly higher (21% than KSF6, but the calculated KDO from SF6 agreed with the calculated KDO from Xe within about 15%; this difference may be due to bubble-enhanced gas transfer. Established empirical equations of KDO using stream characteristics did a poor job predicting KDO for both creeks.

  14. A simple technique for continuous measurement of time-variable gas transfer in surface waters

    Science.gov (United States)

    Tobias, Craig R.; Bohlke, John Karl; Harvey, Judson W.; Busenberg, Eurybiades

    2009-01-01

    Mass balance models of dissolved gases in streams, lakes, and rivers serve as the basis for estimating wholeecosystem rates for various biogeochemical processes. Rates of gas exchange between water and the atmosphere are important and error-prone components of these models. Here we present a simple and efficient modification of the SF6 gas tracer approach that can be used concurrently while collecting other dissolved gas samples for dissolved gas mass balance studies in streams. It consists of continuously metering SF6-saturated water directly into the stream at a low rate of flow. This approach has advantages over pulse injection of aqueous solutions or bubbling large amounts of SF6 into the stream. By adding the SF6 as a saturated solution, we minimize the possibility that other dissolved gas measurements are affected by sparging and/or bubble injecta. Because the SF6 is added continuously we have a record of changing gas transfer velocity (GTV) that is contemporaneous with the sampling of other nonconservative ambient dissolved gases. Over a single diel period, a 30% variation in GTV was observed in a second-order stream (Sugar Creek, Indiana, USA). The changing GTV could be attributed in part to changes in temperature and windspeed that occurred on hourly to diel timescales.

  15. Environmental Impact Assessment of Petrol and Gas Filling Stations ...

    African Journals Online (AJOL)

    This study investigated pollutants emissions from filling stations and their impact on the air quality. Gas monitors were employed to identify the different pollutants present in the ambient air of the study areas. The results showed that the most prominent pollutants present in the ambient air are the volatile organic compounds ...

  16. Physiological and behavioral responses of poultry exposed to gas-filled high expansion foam.

    Science.gov (United States)

    McKeegan, D E F; Reimert, H G M; Hindle, V A; Boulcott, P; Sparrey, J M; Wathes, C M; Demmers, T G M; Gerritzen, M A

    2013-05-01

    Disease control measures require poultry to be killed on farms to minimize the risk of disease being transmitted to other poultry and, in some cases, to protect public health. We assessed the welfare implications for poultry of the use of high-expansion gas-filled foam as a potentially humane, emergency killing method. In laboratory trials, broiler chickens, adult laying hens, ducks, and turkeys were exposed to air-, N2-, or CO2-filled high expansion foam (expansion ratio 300:1) under standardized conditions. Birds were equipped with sensors to measure cardiac and brain activity, and measurements of oxygen concentration in the foam were carried out. Initial behavioral responses to foam were not pronounced but included headshakes and brief bouts of wing flapping. Both N2- and CO2-filled foam rapidly induced ataxia/loss of posture and vigorous wing flapping in all species, characteristic of anoxic death. Immersion in air-filled, high expansion foam had little effect on physiology or behavior. Physiological responses to both N2- and CO2-filled foam were characterized by a pronounced bradyarrythymia and a series of consistent changes in the appearance of the electroencephalogram. These were used to determine an unequivocal time to loss of consciousness in relation to submersion. Mean time to loss of consciousness was 30 s in hens and 18 s in broilers exposed to N2-filled foam, and 16 s in broilers, 1 s in ducks, and 15 s in turkeys exposed to CO2-filled foam. Euthanasia achieved with anoxic foam was particularly rapid, which is explained by the very low oxygen concentrations (below 1%) inside the foam. Physiological observations and postmortem examination showed that the mode of action of high expansion, gas-filled foam is anoxia, not occlusion of the airway. These trials provide proof-of-principle that submersion in gas-filled, high expansion foam provides a rapid and highly effective method of euthanasia, which may have potential to provide humane emergency killing

  17. Novel methodology to perform sulfur hexafluoride (SF6)-based multiple-breath wash-in and washout in infants using current commercially available equipment.

    Science.gov (United States)

    Gustafsson, P M; Robinson, P D; Lindblad, A; Oberli, D

    2016-11-01

    Multiple-breath inert gas washout (MBW) is ideally suited for early detection and monitoring of serious lung disease, such as cystic fibrosis, in infants and young children. Validated commercial options for the MBW technique are limited, and suitability of nitrogen (N 2 )-based MBW is of concern given the detrimental effect of exposure to pure O 2 on infant breathing pattern. We propose novel methodology using commercially available N 2 MBW equipment to facilitate 4% sulfur hexafluoride (SF 6 ) multiple-breath inert gas wash-in and washout suitable for the infant age range. CO 2 , O 2 , and sidestream molar mass sensor signals were used to accurately calculate SF 6 concentrations. An improved dynamic method for synchronization of gas and respiratory flow was developed to take into account variations in sidestream sample flow during MBW measurement. In vitro validation of triplicate functional residual capacity (FRC) assessments was undertaken under dry ambient conditions using lung models ranging from 90 to 267 ml, with tidal volumes of 28-79 ml, and respiratory rates 20-60 per minute. The relative mean (SD, 95% confidence interval) error of triplicate FRC determinations by washout was -0.26 (1.84, -3.86 to +3.35)% and by wash-in was 0.57 (2.66, -4.66 to +5.79)%. The standard deviations [mean (SD)] of percentage error among FRC triplicates were 1.40 (1.14) and 1.38 (1.32) for washout and wash-in, respectively. The novel methodology presented achieved FRC accuracy as outlined by current MBW consensus recommendations (95% of measurements within 5% accuracy). Further clinical evaluation is required, but this new technique, using existing commercially available equipment, has exciting potential for research and clinical use. Copyright © 2016 the American Physiological Society.

  18. Thermal behaviour of high burnup PWR fuel under different fill gas conditions

    International Nuclear Information System (INIS)

    Tverberg, T.

    2001-01-01

    During its more than 40 years of existence, a large number of experiments have been carried out at the Halden Reactor Project focusing on different aspects related to nuclear reactor fuel. During recent years, the fuels testing program has mainly been focusing on aspects related to high burnup, in particular in terms of fuel thermal performance and fission gas release, and often involving reinstrumentation of commercially irradiated fuel. The paper describes such an experiment where a PWR rod, previously irradiated in a commercial reactor to a burnup of ∼50 MWd/kgUO 2 , was reinstrumented with a fuel central oxide thermocouple and a cladding extensometer together with a high pressure gas flow line, allowing for different fill gas compositions and pressures to be applied. The paper focuses on the thermal behaviour of such LWR rods with emphasis on how different fill gas conditions influence the fuel temperatures and gap conductance. Rod growth rate was also monitored during the irradiation in the Halden reactor. (author)

  19. Modifications to Langley 0.3-m TCT adaptive wall software for heavy gas test medium, phase 1 studies

    Science.gov (United States)

    Murthy, A. V.

    1992-01-01

    The scheme for two-dimensional wall adaptation with sulfur hexafluoride (SF6) as test gas in the NASA Langley Research Center 0.3-m Transonic Cryogenic Tunnel (0.3-m TCT) is presented. A unified version of the wall adaptation software has been developed to function in a dual gas operation mode (nitrogen or SF6). The feature of ideal gas calculations for nitrogen operation is retained. For SF6 operation, real gas properties have been computed using the departure function technique. Installation of the software on the 0.3-m TCT ModComp-A computer and preliminary validation with nitrogen operation were found to be satisfactory. Further validation and improvements to the software will be undertaken when the 0.3-m TCT is ready for operation with SF6 gas.

  20. Test of Blanc's law for negative ion mobility in mixtures of SF6 with N2, O2 and air

    International Nuclear Information System (INIS)

    Hinojosa, G; Urquijo, J de

    2003-01-01

    We have measured the mobility of negative ion species drifting in mixtures of SF 6 with N 2 , O 2 and air. The pulsed Townsend experiment was used for this purpose. The conditions of the experiment, high pressures and low values of the reduced electric field, E/N, ensured that the majority species drifting in the gap was SF 6 - , to which the present mobilities are ascribed. The extrapolated, zero field mobilities for several mixture compositions were used to test them successfully with Blanc's law. Moreover, the measured zero field SF 6 - mobilities in air could also be explained in terms of the measured mobilities for this ionic species in N 2 and O 2

  1. Ultrafast Mid-IR Nonlinear Optics in Gas-filled Hollow-core Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Habib, Selim

    Invention of hollow-core fiber has been proven an ideal medium to study light-gas interaction. Tight confinement of light inside hollowcore fiber allows unremitting and tailored interaction between light and gas over long distances. In this work, we used a special kind of hollowcore fiber − hollow......-core anti-resonant (HC-AR) fiber to study the various nonlinear effects filled with Raman free noble gas. One of the main striking features of HC-AR fiber is that ∼99.99% light can be guided inside the central hollow-core region, which significantly enhances damage threshold level. HC-AR fiber can sustain...... be tuned by simply changing the pressure of the gas while at the same time providing extremely wide transparency ranges. In this thesis, we propose several low-loss broadband guidance HC-AR fibers and investigate soliton-plasma dynamics using HC-AR fiber filled with noble gas in the mid-IR. The combined...

  2. Laser triggering of a 500-kV gas-filled switch: A parametric study

    International Nuclear Information System (INIS)

    Woodworth, J.R.; Hargis, P.J. Jr.; Pitchford, L.C.; Hamil, R.A.

    1984-01-01

    We have investigated neodymium: yttrium aluminum garnet (Nd:YAG) laser triggering of a 500-kV, SF 6 -insulated gas switch for a range of laser parameters. Laser wavelengths of 266 nm and 1064 nm with nominal pulse lengths of 2- and 4-nsec full width at half maximum (FWHM) were used to trigger the switch. The switch was triggered by focusing the laser to form a breakdown arc in the gas between the electrodes. Subnanosecond jitter in the operation of the switch was obtained for 266-nm laser pulse energies as low as 5 mJ. Results obtained with the Nd:YAG laser are compared to earlier data in which the switch was triggered with a krypton-fluoride laser operating at 248 nm with a pulse length of 20-nsec FWHM. Our experimental results show that ultraviolet laser triggering gives results which are a dramatic improvement over infrared laser triggering in terms of lower jitter and smaller change in delay time with variations in applied voltage. We also see indications that the optimum laser pulse length is equal to or greater than the closure time of the switch

  3. The Experimental Study of Dynamics of Scaled Gas-Filled Bubble Collapse in Liquid

    Science.gov (United States)

    Pavlenko, Alexander

    2011-06-01

    The article provides results of analyzing special features of the single-bubble sonoluminescence, developing the special apparatus to investigate this phenomenon on a larger-scale basis. Certain very important effects of high energy density physics, i.e. liquid compressibility, shock-wave formation under the collapse of the gas cavity in liquid, shock-wave focusing in the gas-filled cavity, occurrence of hot dense plasma in the focusing area, and high-temperature radiation yield are observed in this phenomenon. Specificity of the process is conditioned by the ``ideal'' preparation and sphericity of the gas-and-liquid contact boundary what makes the collapse process efficient due to the reduced influence of hydrodynamic instabilities. Results of experimental investigations; results of developing the facilities, description of methods used to register parameters of facilities and the system under consideration; analytical estimates how gas-filled bubbles evolve in liquid with the regard for scale effects; results of preliminary 1-D gas dynamic calculations of the gas bubble evolution are presented. The work supported by ISTC Project #2116.

  4. Complications among colorectal cancer survivors: SF-6D preference-weighted quality of life scores.

    Science.gov (United States)

    Hornbrook, Mark C; Wendel, Christopher S; Coons, Stephen Joel; Grant, Marcia; Herrinton, Lisa J; Mohler, M Jane; Baldwin, Carol M; McMullen, Carmit K; Green, Sylvan B; Altschuler, Andrea; Rawl, Susan M; Krouse, Robert S

    2011-03-01

    Societal preference-weighted health-related quality of life (HRQOL) scores enable comparing multidimensional health states across diseases and treatments for research and policy. To assess the effects of living with a permanent intestinal stoma, compared with a major bowel resection, among colorectal cancer (CRC) survivors. Cross-sectional multivariate linear regression analysis to explain preference-weighted HRQOL scores. In all, 640 CRC survivors (≥ 5 years) from 3 group model health maintenance organizations; ostomates and nonostomates with colorectal resections for CRC were matched on gender, age (± 5 years), time since diagnosis, and tumor site (rectum vs. colon). SF-6D scoring system was applied to Medical Outcomes Study Short Form-36 version 2 (SF-36v2); City of Hope Quality of Life-Ostomy; and Charlson-Deyo comorbidity index. Survey of CRC survivors linked to respondents' clinical data extracted from health maintenance organization files. Response rate was 52%. Ostomates and nonostomates had similar sociodemographic characteristics. Mean SF-6D score was 0.69 for ostomates, compared with 0.73 for nonostomates (P ostomy after other factors were taken into account. Surgical complications, comorbidities, and metastatic disease lowered the preference-weighted HRQOL of CRC survivors with and without ostomies. Further research to understand and reduce late complications from CRC surgeries as well as associated depression is warranted.

  5. Test facility for fast gas injections into a vessel filled with water

    International Nuclear Information System (INIS)

    Wilhelm, D.; Kirstahler, M.

    1987-11-01

    The Fast Gas Injection Facility (SGI) was set up to study the hydrodynamics during the expansion of a gas bubble into a vessel filled with water. The gas stored in a pressure vessel expands against gravity through a circular duct into a large cylindrical vessel partly with water. This report covers the description of the test facility and the data acquisition. Results of the first test series are added. (orig.) [de

  6. Interaction of intense electromagnetic fields with SF6 molecules and clusters in supersonic expansion

    International Nuclear Information System (INIS)

    Airoldi, V.J.T.

    1987-01-01

    A method of measuring SF 6 cluster formation and inhibition in pulsed supersonic expansion in the presence of intense electromagnetic radiation is presented. The characterization of the expansion of SF 6 molecules was done and, the extension of the collision region was determined. An improved unidimensional theory of supersonic expansion showed good agreement with the experimental results. The spectra of multiphoton absorption of SF 6 molecules in supersonic jet and the average energy absorved by each molecule were determined. The absorption spectra of molecule in the collision region present absorption maxima different from those obtained in the collisionless region. The results, if compared with the literature data, show good agreement, with a small difference in the spetra corresponding to the collisionless region. This difference was observed, for the first time in the multiphoton absorption and is attribuited to cluster formation in the jet. A new technique for measuring cluster formation in the supersonic jet, based on determination of the spatial distribution of the energy of molecules in the jet after passing through a skimmer located in the collision region is shown. The inhibition of cluster formation, due to the incidence of intense electromagnetic radiation from a CO 2 -TEA pulsed laser in the initial collision region of the jet, causes a second expansion in the skimmer. The results obtained show that this method can lead to a new isotope separation process. All the parts of the experimental set up, for example, high vacuum system, pulsed valve and pyroelectric detector, were developed and constructed specially for the experiment. (Author) [pt

  7. Safety Distances for hydrogen filling stations

    Energy Technology Data Exchange (ETDEWEB)

    Matthijsen, A. J. C. M.; Kooi, E. S.

    2005-07-01

    In the Netherlands there is a growing interest in using natural gas as a transport fuel. The most important drivers behind this development are formed by poor inner city air quality and the decision to close several LPG filling stations. Dwellings are not allowed within the safety distances of 45 or 110 meters from the tanker filling point of these LPG stations, depending on the capacity of the station. Another driver is global warming. We are carrying out a study on station supply, compression, storage and filling for natural gas stations, and a similar, simultaneous study on hydrogen as a followup to our risk analysis for the hydrogen filling station in Amsterdam. Here, three buses drive on hydrogen as part of the European CUTE project. Driving on natural gas is an important step in the transition to cars on hydrogen. This study was commissioned by the Dutch Ministry of Spatial Planning, Housing and the Environment to advise on external safety aspects of future hydrogen filling stations. According to Dutch law homes may not be built within an individual risk contour of 10-6 per year of a dangerous object, such as a plant with hazardous materials or a filling station. An individual risk contour of 10-6 is represented by a line around a dangerous object that connects locations with an individual risk level of 10-6 per year. An individual 'located' within this contour line has a chance of one per million per year or more to be killed as a result of an accident caused by this object. The longest distance between the object and such a contour is called a 'safety distance'. A study on safety distances is now in progress for different kinds of hydrogen filling stations (e. g. gaseous and liquid hydrogen) and for different capacities, such as big, medium and small stations. The focus is on different kinds of hydrogen production and the hydrogen supply of the filling station. To decide on the design and supply of the hydrogen station, we examined the

  8. Development of data logger for atmospheric pressure, temperature and relative humidity for gas-filled detector

    International Nuclear Information System (INIS)

    Sahu, S.; Sahu, P.K.; Bhuyan, M.R.; Biswas, S.; Mohanty, B.

    2014-01-01

    At IoP-NISER an initiative has been taken to build and test micro-pattern gas detector such as Gas Electron Multiplier (GEM) for several upcoming High-Energy Physics (HEP) experiment projects. Temperature (t), atmospheric pressure (p) and relative humidity (RH) monitor and recording is very important for gas filled detector development. A data logger to monitor and record the ambient parameters such as temperature, relative humidity and pressure has been developed. With this data logger continuous recording of t, p, RH and time stamp can be done with a programmable sampling interval. This data is necessary to correct the gain of a gas filled detector

  9. Amplification of spontaneous emission of neon-like argon in a fast gas-filled capillary discharge

    International Nuclear Information System (INIS)

    Kolacek, K.; Schmidt, J.; Bohacek, V.; Ripa, M.; Frolov, O.; Vrba, P.; Straus, J.; Prukner, V.; Rupasov, A. A.; Shikanov, A. S.

    2008-01-01

    The evolution of the CAPEX facility and its basic diagnostics are described. The experiments carried out in the last modification of this facility accomplished with the demonstration of amplified spontaneous emission of neon-like argon (Ar 8+ ) at the wavelength 46.88 nm. The first version of the facility, CAPEX1, operated with a plastic capillary and had a short high-power passive prepulse and an imperfect gas-filling system. In the second version, CAPEX2, a ceramic capillary was used, the prepulse amplitude was lowered, and the gas-filling system was improved. In the third, most successful version, CAPEX3, the capillary bending was reduced, a longer external prepulse was used, and the gas-filling system was further optimized. For each version, results of X-ray measurements are presented and interpreted

  10. Steady-state ozone concentration in radiation induced noble gas-oxygen discharges

    International Nuclear Information System (INIS)

    Elsayed-Ali, H.E.; Miley, G.H.

    1985-01-01

    Measurements of steady-state ozone concentrations in continuous radiation induced noble gas-O 2 and noble gas-O 2 -SF 6 mixtures has been accomplished. The discharges were created through the bombardment of the gases with energetic particles from the boron-10 (n,α) lithium-7 nuclear reaction. Three noble gases were studied, He, Ne, and Ar at partial pressures of few hundred Torr. The dose rates studied were in the order of 10 15 eV.cm -3 .s -1 . The experimental apparatus and proceedure were previously described. The experimentally observed stead-state ozone concentrations in noble gas-O 2 discharges were about an order of magnitude lower than that observed for oxygen radiolysis at similar dose rates. These results were physically explained by an enhanced role of negative ionic reactions with ozone causing its destruction. In noble gas-O 2 -SF 6 mixtures, the steady-state ozone concentrations were found to be significantly higher (3-6 times) than that without the SF 6 addition. This observation was contrary to only a small increase observed after SF 6 addition to a few hundred Torr oxygen and is explained by an enhanced rate of electron dissociative attachment of ozone in noble gas-O 2 discharges

  11. Differentiated muscles are mandatory for gas-filling of the Drosophila airway system

    Directory of Open Access Journals (Sweden)

    Yiwen Wang

    2015-12-01

    Full Text Available At the end of development, organs acquire functionality, thereby ensuring autonomy of an organism when it separates from its mother or a protective egg. In insects, respiratory competence starts when the tracheal system fills with gas just before hatching of the juvenile animal. Cellular and molecular mechanisms of this process are not fully understood. Analyses of the phenotype of Drosophila embryos with malformed muscles revealed that they fail to gas-fill their tracheal system. Indeed, we show that major regulators of muscle formation like Lame duck and Blown fuse are important, while factors involved in the development of subsets of muscles including cardiac and visceral muscles are dispensable for this process, suggesting that somatic muscles (or parts of them are essential to enable tracheal terminal differentiation. Based on our phenotypic data, we assume that somatic muscle defect severity correlates with the penetrance of the gas-filling phenotype. This argues that a limiting molecular or mechanical muscle-borne signal tunes tracheal differentiation. We think that in analogy to the function of smooth muscles in vertebrate lungs, a balance of physical forces between muscles and the elasticity of tracheal walls may be decisive for tracheal terminal differentiation in Drosophila.

  12. HVDC wall bushing performance in wet weather

    International Nuclear Information System (INIS)

    Lambeth, P.J.

    1990-01-01

    There is a history of flashovers of wall bushings in rain, even when they are relatively clean. These flashovers appear to be associated generally with a non- uniform rain distribution because of the shielding effect of the valve hall. This paper reports that a study has been made of this problem involving the development of laboratory test techniques to simulate the critical conditions, and also verification that the rapid flashover clean fog test can be used for evaluating a polluted DC bushing. Using these techniques a conventional bushing has been assessed and a method of improving its performance has been found by fitting it with supplementary silicone-rubber sheds, (booster sheds). The effects of various numbers of such sheds on the bushing have been measured, as have the effects of modifications to the booster shed

  13. Development of bushing material with higher corrosion and wear resistance; Taishoku taimamosei dogokin bush zairyo no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Kira, T; Yokota, H; Kamiya, S [Taiho Kogyo Co. Ltd., Osaka (Japan)

    1997-10-01

    Recent diesel engines require a higher performance and a longer life. Due to higher cylinder pressure, the operating load and temperature of piston pin bushings become higher. Therefore, higher load capacity, higher wear resistance and higher corrosion resistance are required for piston pin bushings. For this reason, we have studied the effect of components added to copper alloy upon the corrosion resistance and the effect of hard particles dispersed in copper matrix upon the wear resistance and the influence of hard particles on the machinablity of materials. Based on the experimental results, we have developed a new bushing material improving wear and corrosion resistance. 17 figs., 3 tabs.

  14. Sulphur hexafluoride gas detection

    CSIR Research Space (South Africa)

    Stolper, R

    2006-02-01

    Full Text Available This poster describes the development process of an electro-optical based solution for detecting and locating SF6 gas leaks at gas insulated switch gear. The principal technologies that were researched are explained with their advantages...

  15. Influence of condensed species on thermo-physical properties of LTE and non-LTE SF6-Cu mixture

    Science.gov (United States)

    Chen, Zhexin; Wu, Yi; Yang, Fei; Sun, Hao; Rong, Mingzhe; Wang, Chunlin

    2017-10-01

    SF6-Cu mixture is frequently formed in high-voltage circuit breakers due to the electrode erosion and metal vapor diffusion. During the interruption process, the multiphase effect and deviation from local thermal equilibrium (non-LTE assumption) can both affect the thermo-physical of the arc plasma and further influence the performance of circuit breaker. In this paper, thermo-physical properties, namely composition, thermodynamic properties and transport coefficients are calculated for multiphase SF6-Cu mixture with and without LTE assumption. The composition is confirmed by combining classical two-temperature mass action law with phase equilibrium condition deduced from second law of thermodynamics. The thermodynamic properties and transport coefficients are calculated using the multiphase composition result. The influence of condensed species on thermo-physical properties is discussed at different temperature, pressure (0.1-10 atm), non-equilibrium degrees (1-10), and copper molar proportions (0-50%). It is found that the multiphase effect has significant influence on specific enthalpy, specific heat and heavy species thermal conductivity in both LTE and non-LTE SF6-Cu system. This paper provides a more accurate database for computational fluid dynamic calculation.

  16. Electron drift velocity in SF{sub 6} in strong electric fields determined from rf breakdown curves

    Energy Technology Data Exchange (ETDEWEB)

    Lisovskiy, V; Yegorenkov, V [Department of Physics and Technology, Kharkov National University, Svobody sq.4, Kharkov 61077 (Ukraine); Booth, J-P [Laboratoire de Physique des Plasmas, Ecole Polytechnique, Palaiseau 91128 (France); Landry, K [Unaxis Displays Division France SAS, 5, Rue Leon Blum, Palaiseau 91120 (France); Douai, D [Physical Sciences Division, Institute for Magnetic Fusion Research, CEA Centre de Cadarache, F-13108 Saint Paul lez Durance Cedex (France); Cassagne, V, E-mail: lisovskiy@yahoo.co [Developpement Photovoltaique Couches Minces, Total, 2, place Jean Millier, La Defense 6, 92400 Courbevoie (France)

    2010-09-29

    This paper presents measurements of the electron drift velocity V{sub dr} in SF{sub 6} gas for high reduced electric fields (E/N = 330-5655 Td (1 Td = 10{sup -17} V cm{sup 2})). The drift velocities were obtained using the method of Lisovskiy and Yegorenkov (1998 J. Phys. D: Appl. Phys. 31 3349) based on the determination of the pressure and voltage of the turning points of rf capacitive discharge breakdown curves for a range of electrode spacings. The V{sub dr} values thus obtained were in good agreement with those calculated from the cross-sections of Phelps and Van Brunt (1988 J. Appl. Phys. 64 4269) using the BOLSIG code. The validity of the Lisovskiy-Yegorenkov method is discussed and we show that it is applicable over the entire E/N range where rf discharge ignition at breakdown occurs for rf frequencies of 13.56 MHz or above.

  17. Beyond Bush: Environmental politics and prospects for US climate policy

    International Nuclear Information System (INIS)

    Harris, Paul G.

    2009-01-01

    The United States was a pioneer in domestic environmental lawmaking, and it was a leader in international environmental cooperation in the final decades of the last century. During the current decade, however, it has moved away from cooperating with other states in finding new ways to protect the global environment. While its early efforts to address climate change were no worse, and often better than, other developed countries, it has fallen far behind as a number of European states and the European Union have started to implement robust policies to reduce their greenhouse gas emissions. This chapter recounts this evolution in US policy from environmental leader to environmental laggard. It summarizes the US climate change-related policies and diplomacy, recounting significant events during the presidential administrations of George HW Bush, Bill Clinton and George W Bush. It then extends this summary of events to assess the prospects for US climate policy in the near future

  18. Design of high power feedthrough for High Power Industrial Accelerator (HPIA)

    International Nuclear Information System (INIS)

    Soni, Rakesh Kumar; Kumar, Abhay; Dwivedi, Jishnu; Kumar, Pankaj; Goswami, S.G.

    2011-01-01

    This paper reports the design, assembly and dismantling and maintenance of a feedthrough for High Power Industrial Accelerator (HPIA). It has been designed to serve three purposes. It provides electrical insulation between primary windings (at ∼ 2.5 kV) and cover flange (at ground potential) with the help of Nylon bushes. It also ensures leak tightness for SF 6 gas filled inside the vessel at 10 bar. It also provides sealing for water connectors between the primary winding and secondary winding. The key function of this feedthrough is to supply ∼ 800 A of current to the primary circuit. Technical requirement/constraint is leak tightness and electrical isolation of feedthrough. This feedthrough will be connected to the primary windings inside the vessel. Current will flow through a copper tube conductor which is at a potential of ∼ 800 V. Inside the tube water is flowing. Inlet water temperature is ∼ 30℃. Flow rate of water is 35 litres/minute at 6 kg/cm 2 pressure to remove the heat losses. (author)

  19. Multigroup Approximation of Radiation Transfer in SF6 Arc Plasmas

    Directory of Open Access Journals (Sweden)

    Milada Bartlova

    2013-01-01

    Full Text Available The first order of the method of spherical harmonics (P1-approximation has been used to evaluate the radiation properties of arc plasmas of various mixtures of SF6 and PTFE ((C2F4n, polytetrafluoroethylene in the temperature range (1000 ÷ 35 000 K and pressures from 0.5 to 5 MPa. Calculations have been performed for isothermal cylindrical plasma of various radii (0.01 ÷ 10 cm. The frequency dependence of the absorption coefficients has been handled using the Planck and Rosseland averaging methods for several frequency intervals. Results obtained using various means calculated for different choices of frequency intervals are discussed.

  20. 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.

  1. ACHP | News | Laura Bush Announces Preserve America Grants Budget

    Science.gov (United States)

    Search skip specific nav links Home arrow News arrow Laura Bush Announces Preserve America Grants Budget Laura Bush Announces Preserve America Grants Budget First Preserve America Communities Also Announced ) Jan. 15, 2004, Washington, DC—Mrs. Laura Bush announced today that the President's budget for FY 2005

  2. George W. Bush in Political Time: The Janus Presidency

    NARCIS (Netherlands)

    Magliocca, G.N.

    2009-01-01

    This essay places George W. Bush's presidency and the Bush administration in some historical context by applying the model of “political time” developed in recent books by Stephen Skowronek (2008) and Keith Whittington (2007). My thesis is that Bush's political failure during his second term was

  3. Modelling of HVDC wall bushing flashover in nonuniform rain

    International Nuclear Information System (INIS)

    Rizk, F.A.M.; Kamel, S.I.

    1991-01-01

    This paper presents the first mathematical model to provide necessary and sufficient conditions for flashover of an HVDC wall bushing under nonuniform rain. The suggested mechanism is initiated by streamer bridging of the dry zone enhanced by nonuniform voltage distribution along the bushing and within the dry zone. Fast voltage collapse across the dry zone die to energy stored in the bushing stray capacitance to ground leads to impulsive stressing of the wet part of the bushing. The nonuniform distribution of the impulse stress and the process of streamer bridging, fast voltage collapse as well as subsequent recharging of the bushing capacitances can lead to continued discharge propagation and flashover of the complete bushing. The findings of the model have been satisfactorily compared with previous experiments and field observations and can, for the first time, account for the following aspects of the flashover mechanism: critical dry zone length, polarity effect, specific leakage path, wet layer conductance per unit leakage length as well as the DC system voltage

  4. Macular hole surgery with short-acting gas and short-duration face-down positioning

    Directory of Open Access Journals (Sweden)

    Xirou T

    2012-07-01

    Full Text Available Tina Xirou,1 Panagiotis G Theodossiadis,2 Michael Apostolopoulos,3 A Stamatina Kabanarou,1 Elias Feretis,1 Ioannis D Ladas,3 Chrysanthi Koutsandrea31Vitreoretinal Unit, Red Cross Hospital, 2B Department of Ophthalmology, University of Athens, Greece; 3A Department of Ophthalmology, University of Athens, GreecePurpose: To report on the outcomes of vitrectomy and sulfur hexafluoride (SF6 gas tamponade for idiopathic macular holes with 2 days of face-down positioning.Patients and methods: This was a prospective, nonrandomized, observational sequential case-series study on 23 consecutive patients receiving macular hole surgery using 20% SF6 and advised to stay in a face-down position for 2 days postoperatively (SF6 group. These patients were compared to 23 consecutive patients who had previously undergone macular hole surgery, had received 14% C3F8, and were advised to maintain a face-down position for 2 days (C3F8 group. Patients in both groups underwent vitrectomy, internal limiting membrane peeling, and fluid gas exchange using either SF6 or C3F8. Preoperative and postoperative data included best corrected visual acuity recorded in LogMAR units, slit-lamp biomicroscopy, and optical coherence tomography.Results: At a 6-month follow-up, macular hole closure was noted in 23/23 eyes (100% and in 22/23 eyes (96% in the SF6 and C3F8 groups, respectively. The improvement in visual acuity (measured through Snellen acuity lines both preoperatively until 6 months postoperatively was 4.08 ± 2.31 (95% confidence interval [CI]: 3.08–5.08 for the SF6 group and 2.87 ± 2.30 (95% CI: 1.87–3.86 for the C3F8 group; this difference was not statistically significant (P = 0.06.Conclusion: Vitrectomy with internal limiting membrane peeling and a short-acting gas tamponade using SF6 with posture limitation for 2 days may give a high success rate in macular hole surgery.Keywords: idiopathic macular holes, SF6 gas tamponade, C3F8 gas tamponade

  5. Control of Butterfly Bush with Postemergence Herbicides

    Science.gov (United States)

    Butterfly bush (Buddleja davidii) is classified as invasive in several parts of the United States. Two experiments were conducted to evaluate the effectiveness of four herbicides and two application methods on postemergence butterfly bush control. The four herbicides included: Roundup (glyphosate)...

  6. A Study of Parameters Related to the Etch Rate for a Dry Etch Process Using NF3/O2 and SF6/O2

    Directory of Open Access Journals (Sweden)

    Seon-Geun Oh

    2014-01-01

    Full Text Available The characteristics of the dry etching of SiNx:H thin films for display devices using SF6/O2 and NF3/O2 were investigated using a dual-frequency capacitively coupled plasma reactive ion etching (CCP-RIE system. The investigation was carried out by varying the RF power ratio (13.56 MHz/2 MHz, pressure, and gas flow ratio. For the SiNx:H film, the etch rates obtained using NF3/O2 were higher than those obtained using SF6/O2 under various process conditions. The relationships between the etch rates and the usual monitoring parameters—the optical emission spectroscopy (OES intensity of atomic fluorine (685.1 nm and 702.89 nm and the voltages VH and VL—were investigated. The OES intensity data indicated a correlation between the bulk plasma density and the atomic fluorine density. The etch rate was proportional to the product of the OES intensity of atomic fluorine (I(F and the square root of the voltages (Vh+Vl on the assumption that the velocity of the reactive fluorine was proportional to the square root of the voltages.

  7. Early Stages of Pulsed-Laser Growth of Silicon Microcolumns and Microcones in Air and SF6

    International Nuclear Information System (INIS)

    Fowlkes, J.D.; Lowndes, D.H.; Pedraza, A.J.

    1999-01-01

    Dense arrays of high-aspect-ratio silicon microcolumns and microcones are formed by cumulative nanosecond pulsed excimer laser irradiation of single-crystal silicon in oxidizing atmospheres such as air and SF 6 . Growth of such surface microstructures requires a redeposition model and also involves elements of self-organization. The shape of the microstructures, i.e. straight columns vs steeply sloping cones and connecting walls, is governed by the type and concentration of the oxidizing species, e.g. oxygen vs fluorine. Growth is believed to occur by a catalyst-free VLS (vapor-liquid-solid) mechanism that involves repetitive melting of the tips of the columns/cones and deposition there of the ablated flux of Si-containing vapor. Results are presented of a new investigation of how such different final microstructures as microcolumns or microcones joined by walls nucleate and develop. The changes in silicon surface morphology were systematically determined and compared as the number of pulsed KrF (248 nm) laser shots was increased from 25 to several thousand in both air and SF 6 . The experiments in air and SF 6 reveal significant differences in initial surface cracking and pattern formation. Consequently, local protrusions are first produced and column or cone/wall growth is initiated by different processes and at different rates. Differences in the spatial organization of column or cone/wall growth also are apparent

  8. Ultraviolet differential optical absorption spectrometry: quantitative analysis of the CS2 produced by SF6 decomposition

    International Nuclear Information System (INIS)

    Zhang, Xiaoxing; Zhou, Hong; Cui, Zhaolun; Xiao, Song; Tang, Ju; Chen, Chuan; Li, Xin

    2017-01-01

    The occurrence of partial discharge or partial overthermal fault in sulfur hexafluoride (SF 6 )-insulated electrical equipment frequently causes SF 6 and solid insulation materials to decompose into various products. One of the most characteristic products of this process is carbon disulfide (CS 2 ). The internal fault type and severity of the fault in the insulation equipment can be detected through the accurate quantitative detection of CS 2 . A device for simultaneously determining and quantifying gaseous CS 2 via ultraviolet differential optical absorption spectrometry is developed in this study. A Sym14 wavelet transform and fast Fourier transform (FFT) are applied to process the spectral data of the feature regions, namely 190 nm to 210 nm. The concentration of CS 2 is determined, and the detection limit of the developed device is identified. A good linear relationship is observed between the characteristic peaks of FFT and the concentration of CS 2 after the operational parameters are optimized. Along the light path at 600 mm, the average detection limit for CS 2 is 8.65 ppb based on three times the standard deviation of the system noises. The proposed device, which exhibits high sensitivity and effective cost, addresses the urgent demand for the monitoring and diagnosis of SF 6 -insulated electrical equipment via online detection of trace CS 2 . (paper)

  9. Steady-state ozone concentrations in radiation induced noble gas-oxygen discharges

    International Nuclear Information System (INIS)

    Elsayed-Ali, H.E.; Miley, G.H.

    1985-01-01

    Measurements of steady-state ozone concentrations in continuous radiation induced noble gas-O/sub 2/ and noble gas-o/sub 2/-SF/sub 6/ mixtures has been accomplished. The discharges were created through the bombardment of the gases with energetic particles from the boron-10 (n,α) lithium-7 nuclear reaction. Three noble gases were studied, He, Ne, and Ar at partial pressures of few hundred Torr. The dose rates studied were in the order of 10/sup 15/ eV . cm/sup -3/ . s/sup -1/. The experimental apparatus and procedure were previously described. The experimentally observed steady-state ozone concentrations in noble gas-O/sub 2/ discharges were about an order of magnitude lower than that observed for oxygen radiolysis at similar dose rates. These results were physically explained by an enhanced role of negative ionic reactions with ozone causing its destruction. In noble gas-O/sub 2/-SF/sub 6/ mixtures, the steady-state ozone concentrations were found to be significantly higher (3-6 times) than that without the SF/sub 6/ addition. This observation was contrary to only a small increase observed after SF/sub 6/ addition to a few hundred Torr oxygen and is explained by an enhanced rate of electron dissociative attachment of ozone in noble gas-O/sub 2/ discharges

  10. Bush and the Energy; Bush et l'energie

    Energy Technology Data Exchange (ETDEWEB)

    Mommaerts, C.; Barre, N.; Riche, P

    2001-07-01

    Facing the increase of the energy demand, Bush the President of the USA, decided to give a new impetus to the nuclear industry. These papers present the economic and the political analysis of this policy from the french point of view showing the anxiety facing the environmental impacts. (A.L.B.)

  11. Signal-Pressure Curves of Cascaded Four-Wave Mixing in Gas-Filled Capillary by fs Pulses

    International Nuclear Information System (INIS)

    Chen Baozhen; Huang Zuqia

    2005-01-01

    The theoretical framework for the cascaded four waves mixing (CFWM) in gas-filled capillary by fs pulses is constructed. Based on the theoretical framework, the signal-pressure curves (SPC) of the CFWM in gas-filled capillary by fs pulses are calculated. With a comparison between the theoretical and experimental SPC we have discussed the influence of the walk-off and phase modulation on the SPC. At the same time, we have discussed the possible origin of the first three peaks of the SPC.

  12. 41 CFR 304-6.5 - What guidelines must we follow when using the Standard Form (SF) 326?

    Science.gov (United States)

    2010-07-01

    ... REQUIREMENTS 6-PAYMENT GUIDELINES Reports § 304-6.5 What guidelines must we follow when using the Standard Form... 41 Public Contracts and Property Management 4 2010-07-01 2010-07-01 false What guidelines must we follow when using the Standard Form (SF) 326? 304-6.5 Section 304-6.5 Public Contracts and Property...

  13. Experience with on-line diagnostics for bushings and current transformers

    Energy Technology Data Exchange (ETDEWEB)

    Brusetti, R.

    2004-02-01

    The application of on-line diagnostic techniques is advocated as an alternative, under certain conditions, for the conventional off-line power factor test used to evaluate the condition of bushings and current transformers. Bushings which are tied to critical system apparatus or which cannot be readily removed from service are considered to be excellent candidates for on-line diagnostics. A case history involving 138-KV bushings is used to demonstrate the value of the on-line diagnostic system which, by taking into account power factor capacitance values along with the rate of change, not only detected the high power factor associated with the bushings, but allowed the high power factor bushings to continue operating with a known problem for over a year. With conventional testing, bushings that exhibited this level of power factor would typically be removed from service. 4 refs., 3 figs.

  14. Ventilation distribution in rats: Part I - The effect of gas composition as measured with electrical impedance tomography

    Directory of Open Access Journals (Sweden)

    Dunster Kimble R

    2012-09-01

    Full Text Available Abstract The measurement of ventilation distribution is currently performed using inhaled tracer gases for multiple breath inhalation studies or imaging techniques to quantify spatial gas distribution. Most tracer gases used for these studies have properties different from that of air. The effect of gas density on regional ventilation distribution has not been studied. This study aimed to measure the effect of gas density on regional ventilation distribution. Methods Ventilation distribution was measured in seven rats using electrical impedance tomography (EIT in supine, prone, left and right lateral positions while being mechanically ventilated with either air, heliox (30% oxygen, 70% helium or sulfur hexafluoride (20% SF6, 20% oxygen, 60% air. The effect of gas density on regional ventilation distribution was assessed. Results Gas density did not impact on regional ventilation distribution. The non-dependent lung was better ventilated in all four body positions. Gas density had no further impact on regional filling characteristics. The filling characteristics followed an anatomical pattern with the anterior and left lung showing a greater impedance change during the initial phase of the inspiration. Conclusion It was shown that gas density did not impact on convection dependent ventilation distribution in rats measured with EIT.

  15. A Head-to-Head Comparison of UK SF-6D and Thai and UK EQ-5D-5L Value Sets in Thai Patients with Chronic Diseases.

    Science.gov (United States)

    Sakthong, Phantipa; Munpan, Wipaporn

    2017-10-01

    Little was known about the head-to-head comparison of psychometric properties between SF-6D and EQ-5D-5L or the different value sets of EQ-5D-5L. Therefore, this study set out to compare the psychometric properties including agreement, convergent, and known-group validity between the SF-6D and the EQ-5D-5L using the real value sets from Thailand and the UK in patients with chronic diseases. 356 adults taking a medication for at least 3 months were identified from a university hospital in Bangkok, Thailand, between July 2014 and March 2015. Agreement was assessed by intraclass correlation coefficients (ICCs) and Bland-Altman plots. Convergent validity was evaluated using Spearman's rank correlation coefficients between SF-6D and EQ-5D-5L and EQ-VAS and SF-12v2. For known-groups validity, the Mann-Whitney U test and Kruskal-Wallis test were used to examine the associations between SF-6D and EQ-5D-5L and patient characteristics. Agreements between the SF-6D and the EQ-5D-5L using Thai and UK value sets were fair, with ICCs of 0.45 and 0.49, respectively. Bland-Altman plots showed that the majority of the SF-6D index scores were lower than the EQ-5D-5L index scores. Both the EQ-5D-5L value sets were more related to the EQ-VAS and physical health, while the SF-6D was more associated with mental health. Both EQ-5D-5L value sets were more sensitive than the SF-6D in discriminating patients with different levels of more known groups except for adverse drug reactions. The SF-6D and both EQ-5D-5L value sets appeared to be valid but sensitive to different outcomes in Thai patients with chronic diseases.

  16. Influence of condensed species on thermo-physical properties of LTE and non-LTE SF6–Cu mixture

    International Nuclear Information System (INIS)

    Chen, Zhexin; Wu, Yi; Yang, Fei; Sun, Hao; Rong, Mingzhe; Wang, Chunlin

    2017-01-01

    SF 6 –Cu mixture is frequently formed in high-voltage circuit breakers due to the electrode erosion and metal vapor diffusion. During the interruption process, the multiphase effect and deviation from local thermal equilibrium (non-LTE assumption) can both affect the thermo-physical of the arc plasma and further influence the performance of circuit breaker. In this paper, thermo-physical properties, namely composition, thermodynamic properties and transport coefficients are calculated for multiphase SF 6 –Cu mixture with and without LTE assumption. The composition is confirmed by combining classical two-temperature mass action law with phase equilibrium condition deduced from second law of thermodynamics. The thermodynamic properties and transport coefficients are calculated using the multiphase composition result. The influence of condensed species on thermo-physical properties is discussed at different temperature, pressure (0.1–10 atm), non-equilibrium degrees (1–10), and copper molar proportions (0–50%). It is found that the multiphase effect has significant influence on specific enthalpy, specific heat and heavy species thermal conductivity in both LTE and non-LTE SF 6 –Cu system. This paper provides a more accurate database for computational fluid dynamic calculation. (paper)

  17. Electrical bushing for a superconductor element

    Science.gov (United States)

    Mirebeau, Pierre; Lallouet, Nicolas; Delplace, Sebastien; Lapierre, Regis

    2010-05-04

    The invention relates to an electrical bushing serving to make a connection at ambient temperature to a superconductor element situated in an enclosure at cryogenic temperature. The electrical bushing passes successively through an enclosure at intermediate temperature between ambient temperature and cryogenic temperature, and an enclosure at ambient temperature, and it comprises a central electrical conductor surrounded by an electrically insulating sheath. According to the invention, an electrically conductive screen connected to ground potential surrounds the insulating sheath over a section that extends from the end of the bushing that is in contact with the enclosure at cryogenic temperature at least as far as the junction between the enclosure at intermediate temperature and the enclosure at ambient temperature. The invention is more particularly applicable to making a connection to a superconductor cable.

  18. The host outer membrane proteins OmpA and OmpC are associated with the Shigella phage Sf6 virion

    International Nuclear Information System (INIS)

    Zhao Haiyan; Sequeira, Reuben D.; Galeva, Nadezhda A.; Tang Liang

    2011-01-01

    Assembly of dsDNA bacteriophage is a precisely programmed process. Potential roles of host cell components in phage assembly haven't been well understood. It was previously reported that two unidentified proteins were present in bacteriophage Sf6 virion (Casjens et al, 2004, J.Mol.Biol. 339, 379-394, Fig. 2A). Using tandem mass spectrometry, we have identified the two proteins as outer membrane proteins (OMPs) OmpA and OmpC from its host Shigella flexneri. The transmission electron cryo-microscopy structure of Sf6 shows significant density at specific sites at the phage capsid inner surface. This density fit well with the characteristic beta-barrel domains of OMPs, thus may be due to the two host proteins. Locations of this density suggest a role in Sf6 morphogenesis reminiscent of phage-encoded cementing proteins. These data indicate a new, OMP-related phage:host linkage, adding to previous knowledge that some lambdoid bacteriophage genomes contain OmpC-like genes that express phage-encoded porins in the lysogenic state.

  19. Hybrid neural network bushing model for vehicle dynamics simulation

    International Nuclear Information System (INIS)

    Sohn, Jeong Hyun; Lee, Seung Kyu; Yoo, Wan Suk

    2008-01-01

    Although the linear model was widely used for the bushing model in vehicle suspension systems, it could not express the nonlinear characteristics of bushing in terms of the amplitude and the frequency. An artificial neural network model was suggested to consider the hysteretic responses of bushings. This model, however, often diverges due to the uncertainties of the neural network under the unexpected excitation inputs. In this paper, a hybrid neural network bushing model combining linear and neural network is suggested. A linear model was employed to represent linear stiffness and damping effects, and the artificial neural network algorithm was adopted to take into account the hysteretic responses. A rubber test was performed to capture bushing characteristics, where sine excitation with different frequencies and amplitudes is applied. Random test results were used to update the weighting factors of the neural network model. It is proven that the proposed model has more robust characteristics than a simple neural network model under step excitation input. A full car simulation was carried out to verify the proposed bushing models. It was shown that the hybrid model results are almost identical to the linear model under several maneuvers

  20. Dependence of energy per molecule on sputtering yields with reactive gas cluster ions

    International Nuclear Information System (INIS)

    Toyoda, Noriaki; Yamada, Isao

    2010-01-01

    Gas cluster ions show dense energy deposition on a target surface, which result in the enhancement of chemical reactions. In reactive sputtering with gas cluster ions, the energy per atom or molecule plays an important role. In this study, the average cluster size (N, the number of atoms or molecules in a cluster ion) was controlled; thereby the dependences of the energy per molecule on the sputtering yields of carbon by CO 2 cluster ions and that of Si by SF 6 /Ar mixed gas cluster ions were investigated. Large CO 2 cluster ions with energy per molecule of 1 eV showed high reactive sputtering yield of an amorphous carbon film. However, these ions did not cause the formation of large craters on a graphite surface. It is possible to achieve very low damage etching by controlling the energy per molecule of reactive cluster ions. Further, in the case of SF 6 /Ar mixed cluster ions, it was found that reactive sputtering was enhanced when a small amount of SF 6 gas (∼10%) was mixed with Ar. The reactive sputtering yield of Si by one SF 6 molecule linearly increased with the energy per molecule.

  1. Effect of gas filling pressure and operation energy on ion and neutron emission in a medium energy plasma focus device

    Science.gov (United States)

    Niranjan, Ram; Rout, R. K.; Srivastava, Rohit; Kaushik, T. C.

    2018-03-01

    The effects of gas filling pressure and operation energy on deuterium ions and neutrons have been studied in a medium energy plasma focus device, MEPF-12. The deuterium gas filling pressure was varied from 1 to 10 mbar at an operation energy of 9.7 kJ. Also, the operation energy was varied from 3.9 to 9.7 kJ at a deuterium gas filling pressure of 4 mbar. Time resolved emission of deuterium ions was measured using a Faraday cup. Simultaneously, time integrated and time resolved emissions of neutrons were measured using a silver activation detector and plastic scintillator detector, respectively. Various characteristics (fluence, peak density, and most probable energy) of deuterium ions were estimated using the Faraday cup signal. The fluence was found to be nearly independent of the gas filling pressure and operation energy, but the peak density and most probable energy of deuterium ions were found to be varying. The neutron yield was observed to be varying with the gas filling pressure and operation energy. The effect of ions on neutrons emission was observed at each operation condition.

  2. Big data integration shows Australian bush-fire frequency is increasing significantly.

    Science.gov (United States)

    Dutta, Ritaban; Das, Aruneema; Aryal, Jagannath

    2016-02-01

    Increasing Australian bush-fire frequencies over the last decade has indicated a major climatic change in coming future. Understanding such climatic change for Australian bush-fire is limited and there is an urgent need of scientific research, which is capable enough to contribute to Australian society. Frequency of bush-fire carries information on spatial, temporal and climatic aspects of bush-fire events and provides contextual information to model various climate data for accurately predicting future bush-fire hot spots. In this study, we develop an ensemble method based on a two-layered machine learning model to establish relationship between fire incidence and climatic data. In a 336 week data trial, we demonstrate that the model provides highly accurate bush-fire incidence hot-spot estimation (91% global accuracy) from the weekly climatic surfaces. Our analysis also indicates that Australian weekly bush-fire frequencies increased by 40% over the last 5 years, particularly during summer months, implicating a serious climatic shift.

  3. Opportunities of influence of plasma streams formed in IKA with continuos nor king gas filling en the surface of materials

    International Nuclear Information System (INIS)

    Useinov, B.M.; Useinova, A.M.; Amrenova, A.U.; Pusankov, S.A.; Sartin, S.A.; Virko, P.G.

    2001-01-01

    The results of the investigation of influence of plasma stream formed in IKA with continuous working gas filling on the surface of stainless steel 12X18H10T and aluminum are given in this article. It is shown here that the effect of influence of plasma stream on the surface of materials depends on the way of working gas filling. There is the comparison of influence of plasma stream formed in plasma accelerator with impulse and continuous working gas filling

  4. Absolute elastic cross sections for electron scattering from SF6

    International Nuclear Information System (INIS)

    Gulley, R.J.; Uhlmann, L.J.; Dedman, C.J.; Buckman, S.J.; Cho, H.; Trantham, K.W.

    2000-01-01

    Full text: Absolute differential cross sections for vibrationally elastic scattering of electrons from sulphur hexafluoride (SF 6 ) have been measured at fixed angles of 60 deg, 90 deg and 120 deg over the energy range of 5 to 15 eV, and also at 11 fixed energies between 2.7 and 75 eV for scattering angles between 10 deg and 180 deg. These measurements employ the magnetic angle-changing technique of Read and Channing in combination with the relative flow technique to obtain absolute elastic scattering cross sections at backward angles (135 deg to 180 deg) for incident energies below 15 eV. The results reveal some substantial differences with several previous determinations and a reasonably good level of agreement with a recent close coupling calculation

  5. Reidid Venemaale / Jason Bush

    Index Scriptorium Estoniae

    Bush, Jason

    2008-01-01

    Korruptsioonist Venemaal Samara piirkonnas, ettevõtte-vaenulikest ülevõtmiskatsetest ja riigiametnike osast selles, Venemaa presidendi algatusest korruptsiooni väljajuurimisel. Vt. samas Jason Bush. BP rasked ajad Venemaal

  6. The Effect of Rain on Air-Water Gas Exchange

    Science.gov (United States)

    Ho, David T.; Bliven, Larry F.; Wanninkhof, Rik; Schlosser, Peter

    1997-01-01

    The relationship between gas transfer velocity and rain rate was investigated at NASA's Rain-Sea Interaction Facility (RSIF) using several SF, evasion experiments. During each experiment, a water tank below the rain simulator was supersaturated with SF6, a synthetic gas, and the gas transfer velocities were calculated from the measured decrease in SF6 concentration with time. The results from experiments with IS different rain rates (7 to 10 mm/h) and 1 of 2 drop sizes (2.8 or 4.2 mm diameter) confirm a significant and systematic enhancement of air-water gas exchange by rainfall. The gas transfer velocities derived from our experiment were related to the kinetic energy flux calculated from the rain rate and drop size. The relationship obtained for mono-dropsize rain at the RSIF was extrapolated to natural rain using the kinetic energy flux of natural rain calculated from the Marshall-Palmer raindrop size distribution. Results of laboratory experiments at RSIF were compared to field observations made during a tropical rainstorm in Miami, Florida and show good agreement between laboratory and field data.

  7. Injection molding of bushes made of tribological PEEK composites

    Directory of Open Access Journals (Sweden)

    2007-12-01

    Full Text Available Polyetheretherketone (PEEK composites have been extensively studied because of the excellent tribological behavior among plastics. However, laboratory specimens and tests are generally discussed, whereas application studies on industrial components are infrequent. In this paper, an injection molded bush made of tribological PEEK was analyzed to correlate wear behavior and molded material structure. Bushes were tested under unlubricated sliding conditions by means of a short wear test. Surface analysis, differential scanning calorimetry (DSC and optical microscopy were used to evaluate the distribution of the different composite fillers (polytetrafluoroethylene, PTFE, graphite particles and carbon microfibers and their effect on the final bush behavior. A significant lack of homogeneity was observed in the molded bush and black bands appeared on the shaft surface after testing due to the sliding. The bush geometry and the injection molding process should be optimized to allow the best tribological behavior of the molded material under working conditions.

  8. Temporal change of SF6 age in spring during rainstorms in a forested headwater catchment, Fukushima, Japan

    Science.gov (United States)

    Sakakibara, Koichi; Tsujimura, Maki; Onda, Yuichi; Iwagami, Sho; Sato, Yutaro; Nagano, Kosuke

    2017-04-01

    Time variant water age in catchments can fundamentally describe catchment function, controlling rainfall-runoff generation, groundwater flow pathway, and water storage. We observed sulfur hexafluoride concentration in the stream and groundwater with 1 - 2 hours interval during rainstorm events in order to reveal temporal variations of rainfall-runoff water age. Target's spring is perennial in a forested headwater catchment with an area of 0.045 square km, Fukushima, Japan. The observed hydrological data and tracer data of water in the catchment (stable isotopic compositions, inorganic solute concentrations) were used for clarifying rainfall-runoff processes related to water age variances. The storm hydrograph and groundwater table clearly responded to rainfall especially with more than 30 mm per day throughout the monitoring period (May 2015 - October 2016). Large variations of SF6 age in spring ranging from zero to 14 years were found in the short period during rainstorms. In particular, the SF6 age in spring was evidently old when the runoff was over 2 mm per day. At the high runoff condition, the SF6 age in spring positively correlated with discharge rate: the spring age became older as the discharge rate increased. With regard to spatial distributions of SF6 age in groundwater, the old groundwater age (9 - 13 years) in the shallow subsurface area along the valley was confirmed after heavy rainfall. This groundwater age was similar age to the deep groundwater at no-rainfall conditions. In addition, inorganic solute concentrations such as chloride ion, sodium ion, and silica in spring water showed dominant levels in the deep and ridge groundwater. All facts suggest that the old groundwater, stored in the ridge or deeper subsurface area, replaced the shallow groundwater in the vicinity of the spring due to heavy rainfall, then it contributed to the spring discharge. Therefore, rainstorm events play important roles as triggers for discharging older water stored in

  9. Ozone-depleting substances and the greenhouse gases HFCs, PFCs and SF{sub 6}. Danish consumption and emissions, 2005

    Energy Technology Data Exchange (ETDEWEB)

    Sander Poulsen, T. [PlanMiljoe (Denmark)

    2007-06-15

    An evaluation of Danish consumption and emissions of ozone-depleting substances and industrial greenhouse gases has been carried out in continuation of previous evaluations, partly to fulfil Denmark's international obligations to provide information within this area and partly to follow the trend in consumption of ozone-depleting substances as well as the consumption and emissions of HFCs, PFCs and SF{sub 6}. The evaluation includes a calculation of actual emissions of HFCs, PFCs, and SF{sub 6} for 2006. In this calculation the release from stock of greenhouse gases in products has been taken into account, and adjustments have been made for imports and exports of the greenhouse gases in products. (BA)

  10. U.S. energy policy and the Bush administration's North American energy strategy

    International Nuclear Information System (INIS)

    Deutsch, K.

    2005-01-01

    This presentation outlined the energy policy in the United States and its impact on frontier development in Alaska, deepwater offshore fields and in the western oil shale resources. The energy strategy focuses on technologies that increase domestic production from existing resources as well as technologies that create new sources of energy. In addition to emphasizing the cooperation between Canada and the United States in ensuring energy supply security and stability, this paper discussed the importance of overall bilateral trade between the 2 countries. It was noted that Canada is the United State's most secure and reliable energy partner and is the number 1 supplier of imported oil, natural gas, electricity and uranium. The Bush administration's energy policy is based on the mandate to supply stable, reliable, secure, affordable and environmentally sound energy for the country's growing economy. The energy strategy focuses on increasing energy supplies, promoting energy conservation, repairing and modernizing the energy infrastructure, protecting the environment and improving energy security. Basic changes to the way energy is produced and used will be needed in order to meet these challenges. Energy security can be met through efficiency gains, diversification and use of alternative energy sources. The strategy involves a balance of supply sources, ranging from increasing domestic oil and gas production to such sources as clean coal generation, nuclear power and hydropower. The policy also balances the use of traditional energy sources with renewables such as geothermal, solar, wind and hydrogen. The United States, Canada and Mexico have identified the following 9 areas as critical for interaction on energy: energy data, electricity, regulatory cooperation, energy efficiency, natural gas, oil sands, nuclear and energy science and technology. Construction of the Alaska Natural Gas Pipeline is also one of the Bush administration's highest priorities, along with

  11. Staged fracturing of horizontal shale gas wells with temporary plugging by sand filling

    Directory of Open Access Journals (Sweden)

    Xing Liang

    2017-03-01

    Full Text Available Due to downhole complexities, shale-gas horizontal well fracturing in the Sichuan Basin suffered from casing deformation and failure to apply the technique of cable-conveyed perforation bridge plug. In view of these problems, a new technique of staged volume fracturing with temporary plugging by sand filling is employed. Based on theoretical analyses and field tests, a design of optimized parameters of coiled tubing-conveyed multi-cluster sand-blasting perforation and temporary plugging by sand filling was proposed. It was applied in the horizontal Well ZJ-1 in which casing deformation occurred. The following results are achieved in field operations. First, this technique enables selective staged fracturing in horizontal sections. Second, this technique can realize massive staged fracturing credibly without mechanical plugging, with the operating efficiency equivalent to the conventional bridge plug staged fracturing. Third, full-hole is preserved after fracturing, thus it is possible to directly conduct an open flow test without time consumption of a wiper trip. The staged volume fracturing with temporary plugging by sand filling facilitated the 14-stage fracturing in Well ZJ-1, with similar SRV to that achieved by conventional bridge plug staged fracturing and higher gas yield than neighboring wells on the same well pad. Thus, a new and effective technique is presented in multi-cluster staged volume fracturing of shale gas horizontal wells.

  12. Insulation Strength and Decomposition Characteristics of a C6F12O and N2 Gas Mixture

    Directory of Open Access Journals (Sweden)

    Xiaoxing Zhang

    2017-08-01

    Full Text Available This paper explores the decomposition characteristics of a new type of environmentally friendly insulating gas C6F12O and N2 mixed gas under AC voltage. The breakdown behavior of 3% C6F12O and N2 mixed gas in quasi-uniform field was investigated through a breakdown experiment. The self-recovery of the mixed gas was analyzed by 100 breakdown experiments. The decomposition products of C6F12O and N2 under breakdown voltage were determined by gas chromatography–mass spectrometer (GC-MS. Finally, the decomposition process of the products was calculated by density functional theory, and the ionization energy, affinity, and molecular orbital gap of the decomposition products were also calculated. The properties of the decomposition products were analyzed from the aspects of insulation and environmental protection. The experimental results show that the 3% C6F12O and N2 mixed gas did not show a downward trend over 100 breakdown tests under a 0.10 MPa breakdown voltage. The decomposition products after breakdown were CF4, C2F6, C3F6, C3F8, C4F10, and C5F12. The ionization energies of several decomposition products are more than 10 eV. The Global Warming Potential (GWP values of the main products are lower than SF6. C2F6, C3F8, and C4F10 have better insulation properties.

  13. Bush blasts 'filth' on TV, school condom handouts.

    Science.gov (United States)

    1991-12-18

    President Bush complained yesterday about the "filth and indecent material" that Americans are exposed to through televised trials. Mr. Bush also criticized programs to combat AIDS that give condoms to teenagers and clean needles to drug addicts. He said such efforts undermine traditional values. He expressed hope that Earvin "Magic" Johnson's revelation that he is HIV positive "will teach people that wayward lifestyles or just kind of unsafe sex at random is not the way it ought to work." Mr. Bush made the comments in a series of satellite television interviews with ABC affiliates in major cities. In an apparent reaction to graphic testimony at the recent Palm Beach rape trial of William Kennedy Smith, Mr. Bush said, "I think the American people have a right to be protected against some of these excesses." Mr. Smith, a nephew of Sen. Edward M. Kennedy, D-Mass., was acquitted last week. The Cable News Network and Court TV provided virtually gavel-to-gavel coverage. Mr. Bush took a dim view of a plan to distribute condoms to juniors and seniors in Philadelphia city high schools as part of a program to combat acquired immune deficiency syndrome. "This is a disease that can be controlled for the most part by individual behavior," Mr. Bush said. "Indeed, I must tell you I'm worried about it. I'm worried about so much filth and indecent material coming in through the airwaves and through these trials into people's homes," he said. full text

  14. Mathematical modeling of filling of gas centrifuge cascade for nickel isotope separation by various feed flow rate

    Science.gov (United States)

    Ushakov, Anton; Orlov, Alexey; Sovach, Victor P.

    2018-03-01

    This article presents the results of research filling of gas centrifuge cascade for separation of the multicomponent isotope mixture with process gas by various feed flow rate. It has been used mathematical model of the nonstationary hydraulic and separation processes occurring in the gas centrifuge cascade. The research object is definition of the regularity transient of nickel isotopes into cascade during filling of the cascade. It is shown that isotope concentrations into cascade stages after its filling depend on variable parameters and are not equal to its concentration on initial isotope mixture (or feed flow of cascade). This assumption is used earlier any researchers for modeling such nonstationary process as set of steady-state concentration of isotopes into cascade. Article shows physical laws of isotope distribution into cascade stage after its filling. It's shown that varying each parameters of cascade (feed flow rate, feed stage number or cascade stage number) it is possible to change isotope concentration on output cascade flows (light or heavy fraction) for reduction of duration of further process to set of steady-state concentration of isotopes into cascade.

  15. Design optimization of the 100 kV HV bushing for ITER-DNB

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Sejal, E-mail: sshah@iter-india.org [ITER-India, Institute for Plasma Research, Gandhinagar 382025, Gujarat (India); Rajesh, S. [ITER-India, Institute for Plasma Research, Gandhinagar 382025, Gujarat (India); Microelectronics and Materials Physics Laboratories, P.O. Box 4500, FIN-90014 University of Oulu (Finland); Srusti, B. [DesignTech Systems Ltd, Banjara Hills, Hyderabad, Andhra Pradesh 500034 (India); Bandyopadhyay, M.; Rotti, C.; Singh, M.J.; Roopesh, G.; Chakraborty, A.K. [ITER-India, Institute for Plasma Research, Gandhinagar 382025, Gujarat (India); Schunke, B.; Hemsworth, R.; Chareyre, J. [ITER Organization, Route de Vinon sur Verdon, 13115 St. Paul lez Durance (France)

    2011-10-15

    The 100 kV bushing of the Diagnostic Neutral Beam (DNB) injector is a cylindrical feedthrough which forms the interface between the gas insulated transmission line and the torus primary vacuum and provides all necessary services to the beam source. All conventions for safety, voltage holding requirement, vacuum compatibility and the choice of materials have been addressed in the design. Finite Element Analyses (FEAs) for the electrostatic and the structural configuration is carried out to validate the design of the High Voltage Bushing (HVB). Several iterations and optimizations of the stress shields are carried out to meet electrostatic criteria, especially at the triple point (the ceramic, metal and vacuum joint), which is critical for good voltage holding. Structural analyses is carried out to assess the stress distribution in the fiber reinforced plastic insulator, the alumina insulator and the integrated HVB for different load cases like operational orientation (horizontal), normal operation and accidental case. Design is further validated for seismic conditions for Seismic Loading-2 (SL-2).

  16. Design optimization of the 100 kV HV bushing for ITER-DNB

    International Nuclear Information System (INIS)

    Shah, Sejal; Rajesh, S.; Srusti, B.; Bandyopadhyay, M.; Rotti, C.; Singh, M.J.; Roopesh, G.; Chakraborty, A.K.; Schunke, B.; Hemsworth, R.; Chareyre, J.

    2011-01-01

    The 100 kV bushing of the Diagnostic Neutral Beam (DNB) injector is a cylindrical feedthrough which forms the interface between the gas insulated transmission line and the torus primary vacuum and provides all necessary services to the beam source. All conventions for safety, voltage holding requirement, vacuum compatibility and the choice of materials have been addressed in the design. Finite Element Analyses (FEAs) for the electrostatic and the structural configuration is carried out to validate the design of the High Voltage Bushing (HVB). Several iterations and optimizations of the stress shields are carried out to meet electrostatic criteria, especially at the triple point (the ceramic, metal and vacuum joint), which is critical for good voltage holding. Structural analyses is carried out to assess the stress distribution in the fiber reinforced plastic insulator, the alumina insulator and the integrated HVB for different load cases like operational orientation (horizontal), normal operation and accidental case. Design is further validated for seismic conditions for Seismic Loading-2 (SL-2).

  17. Low-Cost Production of Composite Bushings for Jet Engine Applications

    Science.gov (United States)

    Gray, Robert A.

    1998-01-01

    The objectives of this research program were to reduce the manufacturing costs of variable stator vane bushings by 1) eliminating the expensive carbon fiber braiding operation, 2) replacing the batch mode impregnation, B-stage, and cutting operations with a continuous process, and 3) reducing the molding cycle and machining operations with injection molding to achieve near-net shapes. Braided bushings were successfully fabricated with both AMB-17XLD and AMB-TPD resin systems. The composite bushings achieved high glass transition temperature after post-cure (+300 C) and comparable weight loss to the PNM-15 bushings. ANM-17XLD bushings made with "batch-mode" molding compound (at 0.5 in. fiber length) achieved a +300 lb-force flange break strength which was superior to the continuous braided-fiber reinforced bushing. The non-MDA resin technology developed in this contract appears attractive for bushing applications that do not exceed a 300 C use temperature. Two thermoplastic polyimide resins were synthesized in order to generate injection molding compound powders. Excellent processing results were obtained at injection temperatures in excess of 300 C. Micro-tensile specimens were produced from each resin type and the Tg measurements (by TMA) for these samples were equivalent to AURUM(R). Thermal Gravimetric Analysis (TGA) conducted at 10 C/min showed that the non-MDA AMB-type polyimide thermoplastics had comparable weight loss to PMR-15 up to 500 C.

  18. Field distribution on an HVDC wall bushing during laboratory rain tests

    International Nuclear Information System (INIS)

    Lampe, W.; Wikstrom, D.; Jacobson, B.

    1991-01-01

    This paper reports that an efficient counter-measure to suppress flashovers across HVDC wall bushings is to make their surfaces hydrophobic. This laboratory investigation reports the measured electric field along such a bushing under different environmental conditions. A significantly reduced radial field strength has been found for the hydrophobic bushing. Moreover, the total field strength distribution becomes almost independent of the prevailing dry zone. The flashover voltage for bushings with a hydrophobic surface is therefore significantly increased

  19. Wall-shaped hohlraum influence on symmetry and energetics in gas-filled hohlraums

    Science.gov (United States)

    Tassin, Veronique; Philippe, Franck; Laffite, Stephane; Videau, Laurent; Monteil, Marie-Christine; Villette, Bruno; Stemmler, Philippe; Bednarczyk, Sophie; Peche, Emilie; Reneaume, Benoit; Thessieux, Christian

    2008-11-01

    On the way to the LMJ completion, achieving ignition with 40 quads in a 2-cone configuration will be attempted as a first step. Theoretical investigation of a rugby-shaped hohlraum shows energetics optimization and a better symmetry control compared to a cylindrical hohlraum [1]. We recently conducted experiments on the Omega laser facility with 3 different wall-shaped methane-filled hohlraum configurations. We present here the experimental results. Energetics benefits are shown for reduced wall area hohlraums. The wall-shaped hohlraum influence on time-dependent radiation symmetry is also discussed. For the 3 gas-filled hohlraums configurations, we compare the foamball early-time radiographs, the D2Ar-filled capsule time-integrated images and the core self-emission images. [1] M. Vandenboomgaerde, Phys. Rev. Lett., 99, 065004 (2007).

  20. Transport coefficients of liquid CF4 and SF6 computed by molecular dynamics using polycenter Lennard-Jones potentials

    International Nuclear Information System (INIS)

    Hoheisel, C.

    1989-01-01

    For several liquid states of CF 4 and SF 6 , the shear and the bulk viscosity as well as the thermal conductivity were determined by equilibrium molecular dynamics (MD) calculations. Lennard-Jones four- and six-center pair potentials were applied, and the method of constraints were chosen for the MD. The computed Green-Kubo integrands show a steep time decay, and no particular longtime behavior occurs. The molecule number dependence of the results is found to be small, and 3 x 10 5 integration steps allow an accuracy of about 10% for the shear viscosity and the thermal conductivity coefficient. Comparison with experimental data shows a fair agreement for CF 4 , while for SF 6 the transport coefficients fall below the experimental ones by about 30%

  1. Fiber optic gas detection system for health monitoring of oil-filled transformer

    Science.gov (United States)

    Ho, H. L.; Ju, J.; Jin, W.

    2009-10-01

    This paper reports the development of a fiber-optic gas detection system capable of detecting three types of dissolved fault gases in oil-filled power transformers or equipment. The system is based on absorption spectroscopy and the target gases include acetylene (C2H2), methane (CH4) and ethylene (C2H4). Low-cost multi-pass sensor heads using fiber coupled micro-optic cells are employed for which the interaction length is up to 4m. Also, reference gas cells made of photonic bandgap (PBG) fiber are implemented. The minimum detectable gas concentrations for methane, acetylene and ethylene are 5ppm, 2ppm and 50ppm respectively.

  2. Study of the average charge states of 188Pb and 252,254No ions at the gas-filled separator TASCA

    International Nuclear Information System (INIS)

    Khuyagbaatar, J.; Ackermann, D.; Andersson, L.-L.; Ballof, J.; Brüchle, W.; Düllmann, Ch.E.; Dvorak, J.; Eberhardt, K.; Even, J.; Gorshkov, A.; Graeger, R.; Heßberger, F.-P.; Hild, D.; Hoischen, R.; Jäger, E.; Kindler, B.

    2012-01-01

    The average charge states of 188 Pb and 252,254 No ions in dilute helium gas were measured at the gas-filled recoil separator TASCA. Hydrogen gas was also used as a filling gas for measurements of the average charge state of 254 No. Helium and hydrogen gases at pressures from 0.2 mbar to 2.0 mbar were used. A strong dependence of the average charge state on the pressure of the filling gases was observed for both, helium and hydrogen. The influence of this dependence, classically attributed to the so-called “density effect”, on the performance of TASCA was investigated. The average charge states of 254 No ions were also measured in mixtures of helium and hydrogen gases at low gas pressures around 1.0 mbar. From the experimental results simple expressions for the prediction of average charge states of heavy ions moving in rarefied helium gas, hydrogen gas, and in their mixture were derived.

  3. s-wave threshold in electron attachment - Observations and cross sections in CCl4 and SF6 at ultralow electron energies

    Science.gov (United States)

    Chutjian, A.; Alajajian, S. H.

    1985-01-01

    The threshold photoionization method was used to study low-energy electron attachment phenomena in and cross sections of CCl4 and SF6 compounds, which have applications in the design of gaseous dielectrics and diffuse discharge opening switches. Measurements were made at electron energies from below threshold to 140 meV at resolutions of 6 and 8 meV. A narrow resolution-limited structure was observed in electron attachment to CCl4 and SF6 at electron energies below 10 meV, which is attributed to the divergence of the attachment cross section in the limit epsilon, l approaches zero. The results are compared with experimental collisional-ionization results, electron-swarm unfolded cross sections, and earlier threshold photoionization data.

  4. Transmucosal gas-loss rates in middle ears initially filled with O2 or CO2.

    Science.gov (United States)

    Kania, Romain E; Vérillaud, Benjamin; Ars, Bernard; Tran Ba Huy, Patrice; Herman, Philippe; Ar, Amos

    2016-10-01

    This study investigates the role of different gases in clearance of gas in the middle ear cavity (ME) by its mucosal blood flow. A rat model was used to measure gas volume changes in the ME cavity at constant pressure without ventilation. We disturbed the normal gas composition of the ME by filling it with O 2 or CO 2 , measured the consequent changes in gas volume over time and compared these results with previously obtained ones for air and N 2 . The first 5 min of the primary transient phase (phase I) for O 2 or CO 2 was characterized by a volume loss decrease of -0.49 ± 0.34 μL and -46.28 ± 8.49 μL, respectively, with volume loss increase for air and N 2 differing greatly, at +0.17 ± 0.17 and +2.31 ± 0.81, respectively. The CO 2 value of -46.28 μL showed that a volume of gas equivalent to that of the ME cleft volume was eliminated within the first 5 min. In the second phase (phase II), all gases showed a linear decrease in volume, which presumably represents a steady-state gas loss rate. However, the gas loss rate of -0.307 ± 0.170 μL min -1 for O 2 -filled MEs was significantly higher than the mean of -0.124 μL min -1 for all other gases. We used a previously established mathematical model to calculate the effective ME mucosal blood flow rate under steady-state (phase II) conditions. The blood flow results for O 2 -filled MEs differed greatly from those of the other gases (89.0 ± 49.28 vs. 26.5 μL min -1 , on average), which suggest that the model used to calculate blood flow should be modified if used with O 2 -filled MEs. Further work should involve a comparison of our method with different methods to verify ME blood flow rate. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Welfare assessment of gas-filled foam as an agent for killing poultry

    NARCIS (Netherlands)

    Gerritzen, M.A.; Reimert, H.G.M.; Hindle, V.A.; Mckeegan, D.E.F.; Sparrey, J.

    2010-01-01

    During outbreaks of notifiable diseases in poultry measures are taken to restrict the spread of the disease. Mass on-farm killing of birds using gasfilled foam is such a measure. This study examines the method and technologies involved using gas-filled foam and looks at the problems involved by

  6. Soliton-plasma nonlinear dynamics in mid-IR gas-filled hollow-core fibers

    DEFF Research Database (Denmark)

    Habib, Selim; Markos, Christos; Bang, Ole

    2017-01-01

    We investigate numerically soliton-plasma interaction in a noble-gas-filled silica hollow-core anti-resonant fiber pumped in the mid-IR at 3.0 mu m. We observe multiple soliton self-compression stages due to distinct stages where either the self-focusing or the self-defocusing nonlinearity...

  7. Insulation design of cryogenic bushing for superconducting electric power applications

    Energy Technology Data Exchange (ETDEWEB)

    Koo, J.Y., E-mail: koojy@hanyang.ac.kr [Department of Electronics, Electrical, Control and Instrumentation Engineering, Hanyang University, Ansan 426-791 (Korea, Republic of); Lee, Y.J.; Shin, W.J.; Kim, Y.H. [Department of Electronics, Electrical, Control and Instrumentation Engineering, Hanyang University, Ansan 426-791 (Korea, Republic of); Kim, J.T. [Department of Electrical Engineering, Daejin University, Pocheon 487-711 (Korea, Republic of); Lee, B.W. [Department of Electronics, Electrical, Control and Instrumentation Engineering, Hanyang University, Ansan 426-791 (Korea, Republic of); Lee, S.H., E-mail: k720lsh@kins.re.kr [Expert Group Electric and Control Department, Korea Institute of Nuclear Safety, Daejeon 305-600 (Korea, Republic of)

    2013-01-15

    Highlights: ► In this paper, design factors of cryogenic bushings were discussed and test results of specimen were introduced in detail. ► We focused on the comparative study of breakdown characteristics of different electrode materials. ► Puncture and creepage breakdown characteristics were analyzed based on the withstand voltage. ► We obtained the basic design factors of extra high voltage condenser bushing. ► We obtained the basic design factors of extra high voltage condenser bushing, which could be used in cryogenic environment. -- Abstract: Recently, the superconductivity projects to develop commercial superconducting devices for extra high voltage transmission lines have been undergoing in many countries. One of the critical components to be developed for high voltage superconducting devices, including superconducting transformers, cables, and fault current limiters, is a high voltage bushing, to supply high current to devices without insulating difficulties, that is designed for cryogenic environments. Unfortunately, suitable bushings for HTS equipment were not fully developed for some cryogenic insulation issues. Such high voltage bushings would need to provide electrical insulation capabilities from room temperature to cryogenic temperatures. In this paper, design factors of cryogenic bushings were discussed and test results of specimen were introduced in detail. First, the dielectric strength of three kinds of metals has been measured with uniform and non-uniform electrodes by withstand voltage of impulse and AC breakdown test in LN{sub 2}. Second, puncture breakdown voltage of glass fiber reinforced plastics (GFRPs) plates has been analyzed with non-uniform electrodes. Finally, creepage discharge voltages were measured according to the configuration of non-uniform and uniform electrode on the FRP plate. From the test results, we obtained the basic design factors of extra high voltage condenser bushing, which could be used in cryogenic

  8. Effect of ambient gas density for diesel spray; Diesel funmu ni taisuru fun`iki mitsudo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Yokohashi, M; Suzuki, T; Oshima, R [Tohokugakuin University, Sendai (Japan); Ono, A [Shinryo Corp., Tokyo (Japan)

    1997-10-01

    Effect of ambient gas density for fuel spray are measured to investigate the Diesel spray behavior. The change of ambient gas density has been given by pressuring N2 gas and using a high density atmospheric pressure SF6 gas. The measurement are performed for the spray penetration and angle. As a result, the spray penetration is confirmed same tendency at the change of density by pressuring N2 and using SF6. Though spray angle is required modification with viscosity. 2 refs., 11 figs.

  9. Determination of absorption coefficient based on laser beam thermal blooming in gas-filled tube.

    Science.gov (United States)

    Hafizi, B; Peñano, J; Fischer, R; DiComo, G; Ting, A

    2014-08-01

    Thermal blooming of a laser beam propagating in a gas-filled tube is investigated both analytically and experimentally. A self-consistent formulation taking into account heating of the gas and the resultant laser beam spreading (including diffraction) is presented. The heat equation is used to determine the temperature variation while the paraxial wave equation is solved in the eikonal approximation to determine the temporal and spatial variation of the Gaussian laser spot radius, Gouy phase (longitudinal phase delay), and wavefront curvature. The analysis is benchmarked against a thermal blooming experiment in the literature using a CO₂ laser beam propagating in a tube filled with air and propane. New experimental results are presented in which a CW fiber laser (1 μm) propagates in a tube filled with nitrogen and water vapor. By matching laboratory and theoretical results, the absorption coefficient of water vapor is found to agree with calculations using MODTRAN (the MODerate-resolution atmospheric TRANsmission molecular absorption database) and HITRAN (the HIgh-resolution atmospheric TRANsmission molecular absorption database).

  10. Northward extension of the known range of the Bush Pipit Anthus ...

    African Journals Online (AJOL)

    Summary. The Bush Pipit Anthus caffer is a partly nomadic African species whose movements coincide with the onset of rains. Across the continent, the distribution and geographic extent of the five Bush Pipit subspecies are poorly known. In Kenya, the documented range of the Bush Pipit is along the Tanzanian border in ...

  11. Genome-wide identification of SF1 and SF2 helicases from archaea.

    Science.gov (United States)

    Chamieh, Hala; Ibrahim, Hiba; Kozah, Juliana

    2016-01-15

    Archaea microorganisms have long been used as model organisms for the study of protein molecular machines. Archaeal proteins are particularly appealing to study since archaea, even though prokaryotic, possess eukaryotic-like cellular processes. Super Family I (SF1) and Super Family II (SF2) helicase families have been studied in many model organisms, little is known about their presence and distribution in archaea. We performed an exhaustive search of homologs of SF1 and SF2 helicase proteins in 95 complete archaeal genomes. In the present study, we identified the complete sets of SF1 and SF2 helicases in archaea. Comparative analysis between archaea, human and the bacteria E. coli SF1 and SF2 helicases, resulted in the identification of seven helicase families conserved among representatives of the domains of life. This analysis suggests that these helicase families are highly conserved throughout evolution. We highlight the conserved motifs of each family and characteristic domains of the detected families. Distribution of SF1/SF2 families show that Ski2-like, Lhr, Sfth and Rad3-like helicases are ubiquitous among archaeal genomes while the other families are specific to certain archaeal groups. We also report the presence of a novel SF2 helicase specific to archaea domain named Archaea Specific Helicase (ASH). Phylogenetic analysis indicated that ASH has evolved in Euryarchaeota and is evolutionary related to the Ski2-like family with specific characteristic domains. Our study provides the first exhaustive analysis of SF1 and SF2 helicases from archaea. It expands the variety of SF1 and SF2 archaeal helicases known to exist to date and provides a starting point for new biochemical and genetic studies needed to validate their biological functions. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Simulation of Bimetallic Bush Hot Rolling Bonding Process

    Directory of Open Access Journals (Sweden)

    Yaqin Tian

    2015-01-01

    Full Text Available Three-dimensional model of bimetallic bush was established including the drive roller and the core roller. The model adopted the appropriate interface assumptions. Based on the bonding properties of bimetallic bush the hot rolling process was analyzed. The optimum reduction ratio of 28% is obtained by using the finite element simulation software MARC on the assumption of the bonding conditions. The stress-strain distribution of three dimensions was research assumptions to interface deformation of rolling. At the same time, based on the numerical simulation, the minimum reduction ratio 20% is obtained by using a double metal composite bush rolling new technology from the experiment research. The simulation error is not more than 8%.

  13. Bush doctrine in the Middle East; The US foreign policy towards the Middle East during the George W. Bush presidency

    Directory of Open Access Journals (Sweden)

    Lukáš Hoder

    2011-06-01

    Full Text Available The article is focused at the most important elements of the US foreign policy towards the Middle East during the administration of George W. Bush (2001 – 2009. The text has two parts. The first part shows three important influences on creation and formulation of the US foreign policy towards the region. At the first place it was an effort to preserve unipolar character of the international system, hegemonic possition of the USA and its dominance in all regions. The second source was specific decision-making process set up by president Bush and the third source of the Bush strategy was a partial transformation of the US longtime policy towards the Middle East. The second part of the article discuss results of the Bush doctrine in the region. The text is focused at five most important consequences of the US foreign policy, which are the fight against proliferation of weapons of mass destruction, the pursuit of the democratization throughout the region, the Israel-Palestinian conflict, regional “cold war” between Iran and Saudi Arabia and finally the struggle to stabilize the post-conflict Iraq.

  14. Hybrid recoil mass analyzer at IUAC – First results using gas-filled ...

    Indian Academy of Sciences (India)

    kinematics (to access heavy nuclei around 200 amu mass and beyond) and both ... totype each of RFQ and DTL are undergoing detailed tests for field ... magnet MD1 in gas-filled mode and is especially attractive in reactions induced by ... calculated using GIOS [11] ion-optical program to get the maximum count rate on.

  15. Dynamics of Dispersive Wave Generation in Gas-Filled Photonic Crystal Fiber with the Normal Dispersion

    Directory of Open Access Journals (Sweden)

    Zhixiang Deng

    2017-01-01

    Full Text Available The absence of Raman and unique pressure-tunable dispersion is the characteristic feature of gas-filled photonic crystal fiber (PCF, and its zero dispersion points can be extended to the near-infrared by increasing gas pressure. The generation of dispersive wave (DW in the normal group velocity dispersion (GVD region of PCF is investigated. It is demonstrated that considering the self-steepening (SS and introducing the chirp of the initial input pulse are two suitable means to control the DW generation. The SS enhances the relative average intensity of blue-shift DW while weakening that of red-shift DW. The required propagation distance of DW emission is markedly varied by introducing the frequency chirp. Manipulating DW generation in gas-filled PCF by the combined effects of either SS or chirp and three-order dispersion (TOD provides a method for a concentrated transfer of energy into the targeted wavelengths.

  16. Developments for transactinide chemistry experiments behind the gas-filled separator TASCA

    International Nuclear Information System (INIS)

    Even, Julia

    2011-01-01

    Topic of this thesis is the development of experiments behind the gas-filled separator TASCA (TransActinide Separator and Chemistry Apparatus) to study the chemical properties of the transactinide elements. In the first part of the thesis, the electrodepositions of short-lived isotopes of ruthenium and osmium on gold electrodes were studied as model experiments for hassium. From literature it is known that the deposition potential of single atoms differs significantly from the potential predicted by the Nernst equation. This shift of the potential depends on the adsorption enthalpy of therndeposited element on the electrode material. If the adsorption on the electrode-material is favoured over the adsorption on a surface made of the same element as the deposited atom, the electrode potential is shifted to higher potentials. This phenomenon is called underpotential deposition. Possibilities to automatize an electro chemistry experiment behind the gas-filled separator were explored for later studies with transactinide elements. The second part of this thesis is about the in-situ synthesis of transition-metal-carbonyl complexes with nuclear reaction products. Fission products of uranium-235 and californium-249 were produced at the TRIGA Mainz reactor and thermalized in a carbon-monoxide containing atmosphere. The formed volatile metal-carbonyl complexes could be transported in a gas-stream. Furthermore, short-lived isotopes of tungsten, rhenium, osmium, and iridium were synthesised at the linear accelerator UNILAC at GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt. The recoiling fusion products were separated from the primary beam and the transfer products in the gas-filled separator TASCA. The fusion products were stopped in the focal plane of TASCA in a recoil transfer chamber. This chamber contained a carbon-monoxide - helium gas mixture. The formed metal-carbonyl complexes could be transported in a gas stream to various experimental setups. All

  17. Bush jätkab maailma dirigeerimist / Neeme Raud

    Index Scriptorium Estoniae

    Raud, Neeme, 1969-

    2004-01-01

    USA president George W. Bush peab oma tagasivalimise kindlustajaks elluviidud välispoliitikat. Autori hinnangul on Bush varasematest presidentidest jõulisemalt muutmas USA-d kapitalismi lipulaevaks, Bushi USA vastandab end euroopalikule mudelile, kus riik tagab kodanikele turvatunde. Kavandatavatest muudatustest USA sisepoliitikas. Vt. samas: Arko Olesk. Verine aasta Iraagi sõjas; Aivar Reinap. USA majandus mustas augus; Andres Keil. Tsivilisatsiooni häirekell

  18. Termination for a superconducting power transmission line including a horizontal cryogenic bushing

    Science.gov (United States)

    Minati, Kurt F.; Morgan, Gerry H.; McNerney, Andrew J.; Schauer, Felix

    1984-01-01

    A termination for a superconducting power transmission line is disclosed which is comprised of a standard air entrance insulated vertical bushing with an elbow, a horizontal cryogenic bushing linking the pressurized cryogenic cable environment to the ambient temperature bushing and a stress cone which terminates the cable outer shield and transforms the large radial voltage gradient in the cable dielectric into a much lower radial voltage gradient in the high density helium coolant at the cold end of the cryogenic bushing.

  19. Why do festival goers drink? Assessment of drinking motives using the DMQ-R SF in a recreational setting.

    Science.gov (United States)

    Németh, Zsófia; Kuntsche, Emmanuel; Urbán, Róbert; Farkas, Judit; Demetrovics, Zsolt

    2011-01-01

    The aim of this study is to confirm the four-dimensional structure and other measurement properties of the Drinking Motives Questionnaire Revised Short Form (DMQ-R SF) among young Hungarian adults in a recreational setting. In a 'Health Tent' at Europe's biggest music and cultural festival, 390 attendees (mean age 23.6, SD = 4.4) completed the DMQ-R SF and answered other alcohol-related questions. Data were analysed by confirmatory factor analysis, repeated measures anova and structural equation modelling. The results confirmed the good measurement properties of the DMQ-R SF in terms of factor loadings, model fit and internal consistency. These statistics were similar for men and women. For both genders, social motives were the most frequently indicated motivational dimension, followed by coping, conformity and enhancement. Social motives were consistently related to drinking, and coping to alcohol-related problems. It seems that the DMQ-R SF is a useful instrument for measuring the motivation to engage in drinking in recreational settings, such as parties, clubs and festivals, where hard-to-reach target groups vulnerable to risky drinking behaviour are present, but time for filling out questionnaires is restricted. © 2010 Australasian Professional Society on Alcohol and other Drugs.

  20. Fission product range effects on HEU fissile gas monitoring for UF6 gas

    International Nuclear Information System (INIS)

    Munro, J.K. Jr.; Valentine, T.E.; Perez, R.B.

    1997-01-01

    The amount of 235 U in UF 6 flowing in a pipe can be monitored by counting gamma rays emitted from fission fragments carried along by the flowing gas. Neutron sources are mounted in an annular sleeve that is filled with moderator material and surrounds the pipe. This provides a source of thermal neutrons to produce the fission fragments. Those fragments that remain in the gas stream following fission are carried past a gamma detector. A typical fragment will be quite unstable, giving up energy as it decays to a more stable isotope with a significant amount of this energy being emitted in the form of gamma rays. A given fragment can emit several gamma rays over its lifetime. The gamma ray emission activity level of a distribution of fission fragments decreases with time. The monitoring system software uses models of these processes to interpret the gamma radiation counting data measured by the gamma detectors

  1. In-beam electron spectrometer used in conjunction with a gas-filled recoil separator

    International Nuclear Information System (INIS)

    Kankaanpaeae, H.; Butler, P.A.; Greenlees, P.T.; Bastin, J.E.; Herzberg, R.D.; Humphreys, R.D.; Jones, G.D.; Jones, P.; Julin, R.; Keenan, A.; Kettunen, H.; Leino, M.; Miettinen, L.; Page, T.; Rahkila, P.; Scholey, C.; Uusitalo, J.

    2004-01-01

    The conversion-electron spectrometer SACRED has been redesigned for use in conjunction with the RITU gas-filled recoil separator. The system allows in-beam recoil-decay-tagging (RDT) measurements of internal conversion electrons. The performance of the system using standard sources and in-beam is described

  2. The "11K" gene family members sf68, sf95 and sf138 modulate transmissibility and insecticidal properties of Spodoptera frugiperda multiple nucleopolyhedrovirus.

    Science.gov (United States)

    Beperet, Inés; Simón, Oihane; Williams, Trevor; López-Ferber, Miguel; Caballero, Primitivo

    2015-05-01

    The "11K" gene family is notable for having homologs in both baculoviruses and entomopoxviruses and is classified as either type 145 or type 150, according to their similarity with the ac145 or ac150 genes of Autographa californica multiple nucleopolyhedrovirus (AcMNPV). One homolog of ac145 (sf138) and two homologs of ac150 (sf68 and sf95) are present in Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV). Recombinant bacmids lacking sf68, sf95 or sf138 (Sf68null, Sf95null and Sf138null, respectively) and the respective repair bacmids were generated from a bacmid comprising the complete virus genome. Occlusion bodies (OBs) of the Sf138null virus were ∼15-fold less orally infective to insects, which was attributed to a 100-fold reduction in ODV infectious titer. Inoculation of insects with Sf138null OBs in mixtures with an optical brightener failed to restore the pathogenicity of Sf138null OBs to that of the parental virus, indicating that the effects of sf138 deletion on OB pathogenicity were unlikely to involve an interaction with the gut peritrophic matrix. In contrast, deletion of sf68 and sf95 resulted in a slower speed-of-kill by 9h, and a concurrent increase in the yield of OBs. Phylogenetic analysis indicated that sf68 and sf95 were not generated after a duplication event of an ancestral gene homologous to the ac150 gene. We conclude that type 145 genes modulate the primary infection process of the virus, whereas type 150 genes appear to have a role in spreading systemic infection within the insect. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Vannevar Bush: Fifty Years Later

    Science.gov (United States)

    Lagowski, J. J.

    1995-12-01

    It is ironic that the 50th anniversary year of Vannevar Bush's Report to President Truman entitled "Science the Endless Frontier", which put into motion the eminently successful current system of education of scientists in this country occurs at a time when serious questions are being asked about the usefulness of that very system. Bush viewed his proposal to establish a national research foundation (later to be called the National Science Foundation) as a "social compact." Judgment of scientific merit would be delegated to expert peers in return for scientific progress, which would ultimately benefit the nation in terms of scientific needs--military security, economic productivity, and enhanced quality of life. Bush wanted the funding of basic research intertwined with training, and preferred to use universities for this purpose rather than industrial or national labs. Bush viewed college and university scientists as teachers and investigators. He believed university-based research would uniquely encourage and engage the next generation of scientists as no other institutional arrangement could. Bush did not trust industry's commitment to basic research, an instinct that proved prophetic. The academic reserve of scientists (PhD's in training and postdoctoral students) that existed before World War II, and upon which the United States could draw for its needs, which were primarily associated with defense efforts, was probably one of the defining factors in Bush's suggested strategy. Currently, that reserve of talent has gotten so large that it is the obvious throttle in the pipeline slowing the continued development of the university research enterprise. Since 1977, the rate at which we have trained new scientists exceeds an average of 4% annually. Since 1987, the "science work force"--PhD's--has grown at three times the rate of the general labor supply. Temporary positions for postdoctoral scientists have grown even faster (over 5% per year since 1989). To compound

  4. Light propagation in gas-filled kagomé hollow core photonic crystal fibres

    Science.gov (United States)

    Rodrigues, Sílvia M. G.; Facão, Margarida; Ferreira, Mário F. S.

    2018-04-01

    We study the propagation of light in kagomé hollow core photonic crystal fibres (HC-PCFs) filled with three different noble gases, namely, helium, xenon and argon. Various properties, including the guided modes, the group-velocity dispersion, and the nonlinear parameter were determined. The zero dispersion wavelength and the nonlinear parameter vary with the gas pressure which may be used to tune the generation of new frequencies using the same pump laser and the same fibre. In the case of the kagomé HC-PCF filled with xenon, the zero dispersion wavelength shifts from 693 to 1973 nm when the pressure is increased from 1 to 150bar, while the effective Kerr nonlinearity becomes comparable to that of silica. We have simulated the propagation of femtosecond pulses launched at 790 nm in order to study the generation of supercontinuum and UV light in kagomé HC-PCFs filled with the noble gases.

  5. Physiological and behavioral responses of poultry exposed to gas-filled high expansion foam

    NARCIS (Netherlands)

    Mckeegan, D.E.F.; Reimert, H.G.M.; Hindle, V.A.; Boulcott, P.; Sparrey, J.M.; Wathes, C.M.; Demmers, T.G.M.; Gerritzen, M.A.

    2013-01-01

    Disease control measures require poultry to be killed on farms to minimize the risk of disease being transmitted to other poultry and, in some cases, to protect public health. We assessed the welfare implications for poultry of the use of high-expansion gas-filled foam as a potentially humane,

  6. Metrological and operational performance of measuring systems used in vehicle compressed natural gas filling stations

    Energy Technology Data Exchange (ETDEWEB)

    Velosa, Jhonn F.; Abril, Henry; Garcia, Luis E. [CDT de GAS (Venezuela). Gas Technological Development Center Corporation

    2008-07-01

    Corporation CDT GAS financially supported by the Colombian government through COLCIENCIAS, carried out a study aimed at designing, developing and implementing in Colombia a calibration and metrological verification 'specialized service' for gas meters installed at dispensers of filling stations using compressed natural gas. The results permitted the identification of improving opportunities (in measuring systems, equipment and devices used to deliver natural gas) which are focused on achieving the highest security and reliability of trading processes of CNG for vehicles. In the development of the first stage of the project, metrological type variables were initially considered, but given the importance of the measuring system and its interaction with the various elements involving gas supply to the filling station, the scope of the work done included aspects related to the operational performance, that is, those influencing the security of the users and the metrological performance of the measuring system. The development of the second stage counted on the collaboration of national companies from the sector of CNG for vehicles, which permitted the carrying out of multiple calibrations to the measuring systems installed in the CNG dispensers, thus achieving, in a concrete way, valid and reliable technological information of the implemented procedures. (author)

  7. Demonstrated high performance of gas-filled rugby-shaped hohlraums on Omega

    Energy Technology Data Exchange (ETDEWEB)

    Philippe, F.; Villette, B. [CEA, DAM, DIF, F-91297 Arpajon (France); Michel, P. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Petrasso, R. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Stoeckl, C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Giraldez, E. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Tassin, V.; Depierreux, S.; Gauthier, P.; Masson-Laborde, P. E.; Monteil, M. C.; Seytor, P.; Lasinski, B.; Park, H. S.; Ross, J. S.; Amendt, P.; Döppner, T.; Hinkel, D. E.; Wallace, R.; Williams, E.; and others

    2014-07-15

    A direct experimental comparison of rugby-shaped and cylindrical shaped gas-filled hohlraums on the Omega laser facility demonstrates that higher coupling and minimal backscatter can be achieved in the rugby geometry, leading to significantly enhanced implosion performance. A nearly 50% increase of x-ray drive is associated with earlier bangtime and increase of neutron production. The observed drive enhancement from rugby geometry in this study is almost twice stronger than in previously published results.

  8. Demonstrated high performance of gas-filled rugby-shaped hohlraums on Omega

    Science.gov (United States)

    Philippe, F.; Tassin, V.; Depierreux, S.; Gauthier, P.; Masson-Laborde, P. E.; Monteil, M. C.; Seytor, P.; Villette, B.; Lasinski, B.; Park, H. S.; Ross, J. S.; Amendt, P.; Döppner, T.; Hinkel, D. E.; Wallace, R.; Williams, E.; Michel, P.; Frenje, J.; Gatu-Johnson, M.; Li, C. K.; Petrasso, R.; Glebov, V.; Sorce, C.; Stoeckl, C.; Nikroo, A.; Giraldez, E.

    2014-07-01

    A direct experimental comparison of rugby-shaped and cylindrical shaped gas-filled hohlraums on the Omega laser facility demonstrates that higher coupling and minimal backscatter can be achieved in the rugby geometry, leading to significantly enhanced implosion performance. A nearly 50% increase of x-ray drive is associated with earlier bangtime and increase of neutron production. The observed drive enhancement from rugby geometry in this study is almost twice stronger than in previously published results.

  9. Demonstrated high performance of gas-filled rugby-shaped hohlraums on Omega

    International Nuclear Information System (INIS)

    Philippe, F.; Villette, B.; Michel, P.; Petrasso, R.; Stoeckl, C.; Giraldez, E.; Tassin, V.; Depierreux, S.; Gauthier, P.; Masson-Laborde, P. E.; Monteil, M. C.; Seytor, P.; Lasinski, B.; Park, H. S.; Ross, J. S.; Amendt, P.; Döppner, T.; Hinkel, D. E.; Wallace, R.; Williams, E.

    2014-01-01

    A direct experimental comparison of rugby-shaped and cylindrical shaped gas-filled hohlraums on the Omega laser facility demonstrates that higher coupling and minimal backscatter can be achieved in the rugby geometry, leading to significantly enhanced implosion performance. A nearly 50% increase of x-ray drive is associated with earlier bangtime and increase of neutron production. The observed drive enhancement from rugby geometry in this study is almost twice stronger than in previously published results

  10. Demonstrated high performance of gas-filled rugby-shaped hohlraums on Omega

    Energy Technology Data Exchange (ETDEWEB)

    Philippe, F. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Tassin, V. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Depierreux, S. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Gauthier, P. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Masson-Laborde, P. E. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Monteil, M. C. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Seytor, P. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Villette, B. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Lasinski, B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Park, H. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ross, J. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Amendt, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Doeppner, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hinkel, D. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wallace, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Williams, E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Michel, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Frenje, J. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; Gatu-Johnson, M. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; Li, C. K. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; Petrasso, R. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; Glebov, V. [Univ. of Rochester, NY (United States). Lab. for Laser Energetics; Sorce, C. [Univ. of Rochester, NY (United States). Lab. for Laser Energetics; Stoeckl, C. [Univ. of Rochester, NY (United States). Lab. for Laser Energetics; Nikroo, A. [General Atomics, San Diego, CA (United States); Giraldez, E. [General Atomics, San Diego, CA (United States)

    2014-07-25

    A direct experimental comparison of rugby-shaped and cylindrical shaped gas-filled hohlraums on the Omega laser facility demonstrates that higher coupling and minimal backscatter can be achieved in the rugby geometry, leading to significantly enhanced implosion performance. A nearly 50% increase of x-ray drive is associated with earlier bangtime and increase of neutron production. The observed drive enhancement from rugby geometry in this study is almost twice stronger than in previously published results.

  11. Thermodynamic and transport properties of two-temperature SF6 plasmas

    International Nuclear Information System (INIS)

    Wang Weizong; Rong Mingzhe; Wu Yi; Spencer, Joseph W.; Yan, Joseph D.; Mei, DanHua

    2012-01-01

    This paper deals with thermodynamic and transport properties of SF 6 plasmas in a two-temperature model for both thermal equilibrium and non-equilibrium conditions. The species composition and thermodynamic properties are numerically determined using the two-temperature Saha equation and Guldberg-Waage equation according to deviation of van de Sanden et al. Transport properties including diffusion coefficient, viscosity, thermal conductivity, and electrical conductivity are calculated with most recent collision interaction potentials by adopting Devoto’s electron and heavy particle decoupling approach but expanded to the third-order approximation (second-order for viscosity) in the frame of Chapman–Enskog method. The results are computed for various values of pressures from 0.1 atm to 10 atm and ratios of the electron temperature to the heavy particle temperature from 1 to 20 with electron temperature range from 300 to 40 000 K. In the local thermodynamic equilibrium regime, results are compared with available results of previously published studies.

  12. AMS of 93Zr: Passive absorber versus gas-filled magnet

    Science.gov (United States)

    Hain, Karin; Deneva, Boyana; Faestermann, Thomas; Fimiani, Leticia; Gómez-Guzmán, José Manuel; Koll, Dominik; Korschinek, Gunther; Ludwig, Peter; Sergeyeva, Victoria; Thiollay, Nicolas

    2018-05-01

    Two different isobar separation techniques were tested for the detection of the long-lived fission product 93Zr (T1/2 = 1.64 · 106 a) using Accelerator Mass Spectrometry (AMS), i.e. a passive absorber and a gas-filled magnet, respectively. Both techniques were used in combination with a Time-of-Flight path for the identification of the stable neighboring isotopes 92Zr and 94Zr. The passive absorber was represented by a stack of silicon nitride foils for high flexibility regarding the thickness for optimal isobar separation. Ion beams with a large variety of energies, between 80 and 180 MeV, were provided for this experiment by the tandem accelerator at the Maier-Leibnitz Laboratory in Garching, Germany. With these beams, the stopping powers of 93Zr and 93Nb as a function of energy were determined experimentally and compared to the results obtained with the simulation program SRIM. Considerable discrepancies regarding the energy dependence of the two stopping power curves relative to each other were found. The lowest detection limit for 93Zr achieved with the passive absorber setup was 93Zr/Zr = 1 · 10-10. In comparison, by optimizing the gas-filled magnet set-up, 93Nb was suppressed by around six orders of magnitude and a detection limit of 93Zr/Zr = 5 · 10-11 was obtained. To our knowledge, these results represent the lowest detection limit achieved for 93Zr until now.

  13. Characteristics of Noble Gas-filled Ionization Chambers for a Low Dose Rate Monitoring

    International Nuclear Information System (INIS)

    Kim, Han Soo; Park, Se Hwan; Ha, Jan Ho; Lee, Jae Hyung; Lee, Nam Ho; Kim, Jung Bok; Kim, Yong Kyun; Kim, Do Hyun; Cho, Seung Yeon

    2007-01-01

    An ionization chamber is still widely used in fields such as an environmental radiation monitoring, a Radiation Monitoring System (RMS) in nuclear facilities, and an industrial application due to its operational stability for a long period and its designs for its applications. Ionization chambers for RMS and an environmental radiation monitoring are requested to detect a low dose rate at as low as 10-2 mR/h and several 3R/h, respectively. Filling gas and its pressure are two of the important factors for an ionization chamber development to use it in these fields, because these can increase the sensitivity of an ionization chamber. We developed cylindrical and spherical ionization chambers for a low dose rate monitoring. Response of a cylindrical ionization chamber, which has a 1 L active volume, was compared when it was filled with Air, Ar, and Xe gas respectively. Response of a spherical ionization chamber was also compared in the case of 9 atm and 25 atm filling-pressures. An inter-comparison with a commercially available high pressure Ar ionization chamber and a fabricated ionization chamber was also performed. A High Pressure Xenon (HPXe) ionization chamber, which was configured with a shielding mesh to eliminate an induced charge of positive ions, was fabricated both for the measurement of an environmental dose rate and for the measurement of an energy spectrum

  14. Rhetorical and Linguistic Analysis of Bush's Second Inaugural Speech

    Science.gov (United States)

    Sameer, Imad Hayif

    2017-01-01

    This study attempts to analyze Bush's second inaugural speech. It aims at investigating the use of linguistic strategies in it. It resorts to two models which are Aristotle's model while the second is that of Atkinson's (1984) to draw the attention towards linguistic strategies. The analysis shows that Bush's second inaugural speech is successful…

  15. Bush and the Energy

    International Nuclear Information System (INIS)

    Mommaerts, C.; Barre, N.; Riche, P.

    2001-01-01

    Facing the increase of the energy demand, Bush the President of the USA, decided to give a new impetus to the nuclear industry. These papers present the economic and the political analysis of this policy from the french point of view showing the anxiety facing the environmental impacts. (A.L.B.)

  16. A Concept for a Low Pressure Noble Gas Fill Intervention in the IFE Fusion Test Facility (FTF) Target Chamber

    International Nuclear Information System (INIS)

    Gentile, C.A.; Blanchard, W.R.; Kozub, T.A.; Aristova, M.; McGahan, C.; Natta, S.; Pagdon, K.; Zelenty, J.

    2010-01-01

    An engineering evaluation has been initiated to investigate conceptual engineering methods for implementing a viable gas shield strategy in the Fusion Test Facility (FTF) target chamber. The employment of a low pressure noble gas in the target chamber to thermalize energetic helium ions prior to interaction with the wall could dramatically increase the useful life of the first wall in the FTF reactor1. For the purpose of providing flexibility, two target chamber configurations are addressed: a five meter radius sphere and a ten meter radius sphere. Experimental studies at Nike have indicated that a low pressure, ambient gas resident in the target chamber during laser pulsing does not appear to impair the ability of laser light from illuminating targets2. In addition, current investigations into delivering, maintaining, and processing low pressure gas appear to be viable with slight modification to current pumping and plasma exhaust processing technologies3,4. Employment of a gas fill solution for protecting the dry wall target chamber in the FTF may reduce, or possibly eliminate the need for other attenuating technologies designed for keeping He ions from implanting in first wall structures and components. The gas fill concept appears to provide an effective means of extending the life of the first wall while employing mostly commercial off the shelf (COTS) technologies. Although a gas fill configuration may provide a methodology for attenuating damage inflicted on chamber surfaces, issues associated with target injection need to be further analyzed to ensure that the gas fill concept is viable in the integrated FTF design5. In the proposed system, the ambient noble gas is heated via the energetic helium ions produced by target detonation. The gas is subsequently cooled by the chamber wall to approximately 800oC, removed from the chamber, and processed by the chamber gas processing system (CGPS). In an optimized scenario of the above stated concept, the chamber

  17. 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.

  18. Bush Pledges Increased Science Research and Education Funding

    Science.gov (United States)

    Kumar, Mohi

    2006-02-01

    In his 31 January State of the Union address, U.S. President George W. Bush announced two new initiatives aimed at galvanizing scientific research and education. For the American Competitiveness Initiative, Bush proposes to ``double the federal commitment to the most critical basic research programs in the physical sciences in the next 10 years. . .[and to] make permanent the research and development tax credit to encourage bolder private-sector initiative in technology.''

  19. The Effect of Altitude on Intraocular Pressure in Vitrectomized Eyes with Sulfur Hexafluoride Tamponade by the Friedenwald Method: Rabbit Animal Model

    Directory of Open Access Journals (Sweden)

    Jans Fromow-Guerra

    2016-01-01

    Full Text Available The aim of this study is to assess the change in intraocular pressure after a road trip, in eyes with different levels of filling with gas tamponade. Five rabbit eyes were subject to pars plana vitrectomy and gas tamponade (filling percentage: 25%, 50%, and 100% of nonexpansile SF6, 100% saline solution, and 100% room air. A sixth eye was injected with 0.35 cc of undiluted SF6 without vitrectomy. Guided by global positioning system, they were driven to the highest point of the highway connecting Mexico City with Puebla city and back, stopping every 300 m to assess intraocular pressure. The rabbit’s scleral rigidity and estimation for human eyes were done by using the Friedenwald nomogram. Maximum altitude was 3209 m (Δ949 m. There were significant differences in intraocular pressure on the rabbit eyes filled with SF6 at 100%, 50%, 25%, and 100% room air. Per every 100 m of altitude rise, the intraocular pressure increased by 1.53, 1.0046, 0.971, and 0.97 mmHg, respectively. Using the human Friedenwald rigidity coefficient, the human eye estimate for intraocular pressure change was 2.1, 1.8, 1.4, and 1.1 mmHg per every 100 m of attitude rise. Altitude changes have a significant impact on intraocular pressure. The final effect depends on the percentage of vitreous cavity fill and scleral rigidity.

  20. How Bush Was 'Churchilled' in Iraq

    National Research Council Canada - National Science Library

    Porch, Douglas

    2004-01-01

    .... Since it took office, the Bush administration has argued that the United States should return to strategies of preemption, unilateralism, and hegemony that characterized American national security...

  1. 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.

  2. An ethnobotany of Western Cape Rasta bush medicine.

    Science.gov (United States)

    Aston Philander, Lisa

    2011-11-18

    This descriptive ethnobiological research is the first documentation of the materials utilized in the pharmacopeia of a novel group of herbalists, Rasta bush doctors, found in the botanically diverse Western Cape of South Africa. This article suggests that medicinal plants used by bush doctors unite the disparate ethnomedicines found in South Africa. Ethnospecies name and parts used were recorded during detailed inventories of 39 bush doctors. Collection of voucher specimens for botanical identification occurred in 15 locations. Herbal remedies were classified into use categories and were compared to historical ethnobotanical literature to ascertain previous cultural affiliations. There were 205 ethnospecies found in the Rastafari ethnobiology, 181 were used medicinally. Ethnospecies belong to 71 plant families and 71% belonged to six plant families: Rutaceae (13), Asteraceae (13), Apiaceae (9), Lamiaceae (8), Fabaceae (8), and Euphorbiaceae (7). The majority of remedies (49%) were foliage. Medicinal plants treated over 30 ailments including: gastrointestinal symptoms (11%), urogential complaints (11%), skin ailments (9%), and cardiovascular diseases (8%). Bush doctors appropriated remedies traditionally important to Zulu, KhoiSan, European and Xhosa healing traditions. Novel plants and plant utilization were noted for 22 plant species. Use of previously undocumented plant materials as medicinals denote distinct local knowledge including novel Rastafarian utilization of herbs for spiritual and ritual purposes. The range of the largely herbaceous pharmacopeia is narrow compared to the region's highly biodiverse materials and historical records of medicinal use. Bush doctors' experimentation with known herbal remedies illustrates a striking level of cross-cultural adaptation. This syncretic pharmacopeia reflects the cultural diversity of Southern Africa, drawing upon recent invasive species, European influence and traditional herbs used by the KhoiSan, Zulu and Xhosa

  3. Laser parametric instability experiments of a 3ω, 15 kJ, 6-ns laser pulse in gas-filled hohlraums at the Ligne d'Intégration Laser facility

    Energy Technology Data Exchange (ETDEWEB)

    Rousseaux, C.; Huser, G.; Loiseau, P.; Casanova, M.; Alozy, E.; Villette, B.; Wrobel, R. [Commissariat à l' Energie Atomique, DAM, DIF, F-91297 Arpajon (France); Henry, O.; Raffestin, D. [Commissariat à l' Energie Atomique, DAM, CESTA, F-33114 Le Barp (France)

    2015-02-15

    Experimental investigation of stimulated Raman (SRS) and Brillouin (SBS) scattering have been obtained at the Ligne-d'Intégration-Laser facility (LIL, CEA-Cesta, France). The parametric instabilities (LPI) are driven by firing four laser beamlets (one quad) into millimeter size, gas-filled hohlraum targets. A quad delivers energy on target of 15 kJ at 3ω in a 6-ns shaped laser pulse. The quad is focused by means of 3ω gratings and is optically smoothed with a kinoform phase plate and with smoothing by spectral dispersion-like 2 GHz and/or 14 GHz laser bandwidth. Open- and closed-geometry hohlraums have been used, all being filled with 1-atm, neo-pentane (C{sub 5}H{sub 12}) gas. For SRS and SBS studies, the light backscattered into the focusing optics is analyzed with spectral and time resolutions. Near-backscattered light at 3ω and transmitted light at 3ω are also monitored in the open geometry case. Depending on the target geometry (plasma length and hydrodynamic evolution of the plasma), it is shown that, at maximum laser intensity about 9 × 10{sup 14} W/cm{sup 2}, Raman reflectivity noticeably increases up to 30% in 4-mm long plasmas while SBS stays below 10%. Consequently, laser transmission through long plasmas drops to about 10% of incident energy. Adding 14 GHz bandwidth to the laser always reduces LPI reflectivities, although this reduction is not dramatic.

  4. Comparing damage on retrieved total elbow replacement bushings with lab worn specimens subjected to varied loading conditions.

    Science.gov (United States)

    Willing, Ryan

    2018-01-09

    Complication rates following total elbow replacement (TER) with conventional implants are relatively high due to mechanical failure involving the UHMWPE bushings. Unfortunately, there are no standardized pre-clinical durability testing protocols for assessing the durability of TER components. This study examines the damage observed on retrieved humeral bushings, and then uses in vitro durability testing with two different loading protocols to compare resulting damage. Damage on 25 pairs of retrieved humeral bushings was characterized using micro-computed tomographic imaging techniques. The damage was compared with that of in vitro test specimens which were subjected to 200 K cycles of either high joint reaction force (high JRF) or high varus moment (high VM) loading. Material removal (mass loss) from bushing components was measured using gravimetric techniques. Thinning was less for retrieved bushings which were still assembled in their humeral component, versus bushings which were loose (0.3 ± 0.3 mm vs. 0.6 ± 0.3 mm, p = 0.02). Comparing in vitro test specimens, thinning due to high VM loading was 0.9 ± 0.3 mm, versus 0.2 ± 0.0 mm for high JRF loading (p = 0.08); however, the actual material removal rates from the humeral bushings were not different between the two protocols (48 ± 5 mm 3 /Mc vs. 43 ± 2 mm 3 /Mc, p = 1). Neither loading protocol could produce damage patterns fully representative of the spectrum of damage patterns observed on clinical retrievals. Pre-clinical testing should employ multiple loading protocols to characterize implant performance under a broader spectrum of usage. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  5. Transport coefficients of liquid CF4 and SF6 computed by molecular dynamics using polycenter Lennard-Jones potentials

    Science.gov (United States)

    Hoheisel, C.

    1989-01-01

    For several liquid states of CF4 and SF4, the shear and the bulk viscosity as well as the thermal conductivity were determined by equilibrium molecular dynamics (MD) calculations. Lennard-Jones four- and six-center pair potentials were applied, and the method of constraints was chosen for the MD. The computed Green-Kubo integrands show a steep time decay, and no particular longtime behavior occurs. The molecule number dependence of the results is found to be small, and 3×105 integration steps allow an accuracy of about 10% for the shear viscosity and the thermal conductivity coefficient. Comparison with experimental data shows a fair agreement for CF4, while for SF6 the transport coefficients fall below the experimental ones by about 30%.

  6. High Throughput Phenotyping of Blueberry Bush Morphological Traits Using Unmanned Aerial Systems

    Directory of Open Access Journals (Sweden)

    Aaron Patrick

    2017-12-01

    Full Text Available Phenotyping morphological traits of blueberry bushes in the field is important for selecting genotypes that are easily harvested by mechanical harvesters. Morphological data can also be used to assess the effects of crop treatments such as plant growth regulators, fertilizers, and environmental conditions. This paper investigates the feasibility and accuracy of an inexpensive unmanned aerial system in determining the morphological characteristics of blueberry bushes. Color images collected by a quadcopter are processed into three-dimensional point clouds via structure from motion algorithms. Bush height, extents, canopy area, and volume, in addition to crown diameter and width, are derived and referenced to ground truth. In an experimental farm, twenty-five bushes were imaged by a quadcopter. Height and width dimensions achieved a mean absolute error of 9.85 cm before and 5.82 cm after systematic under-estimation correction. Strong correlation was found between manual and image derived bush volumes and their traditional growth indices. Hedgerows of three Southern Highbush varieties were imaged at a commercial farm to extract five morphological features (base angle, blockiness, crown percent height, crown ratio, and vegetation ratio associated with cultivation and machine harvestability. The bushes were found to be partially separable by multivariate analysis. The methodology developed from this study is not only valuable for plant breeders to screen genotypes with bush morphological traits that are suitable for machine harvest, but can also aid producers in crop management such as pruning and plot layout organization.

  7. 'Shakespeare in the bush' and encountering the other in the ...

    African Journals Online (AJOL)

    'Shakespeare in the bush' and encountering the other in the hermeneutical dialectic of belonging and distanciation 'Shakespeare in the Bush' is an account of an anthropologist's hermeneutical experience among the Tiv people of Nigeria that serves as an illustration o f a hermeneutical circle which results in transforming ...

  8. Comparison of the Multiattribute Utility Instruments EQ-5D and SF-6D in a Europe-Wide Population-Based Cohort of Patients with Inflammatory Bowel Disease 10 Years after Diagnosis.

    Science.gov (United States)

    Huppertz-Hauss, Gert; Aas, Eline; Lie Høivik, Marte; Langholz, Ebbe; Odes, Selwyn; Småstuen, Milada; Stockbrugger, Reinhold; Hoff, Geir; Moum, Bjørn; Bernklev, Tomm

    2016-01-01

    Background. The treatment of chronic inflammatory bowel disease (IBD) is costly, and limited resources call for analyses of the cost effectiveness of therapeutic interventions. The present study evaluated the equivalency of the Short Form 6D (SF-6D) and the Euro QoL (EQ-5D), two preference-based HRQoL instruments that are broadly used in cost-effectiveness analyses, in an unselected IBD patient population. Methods. IBD patients from seven European countries were invited to a follow-up visit ten years after their initial diagnosis. Clinical and demographic data were assessed, and the Short Form 36 (SF-36) was employed. Utility scores were obtained by calculating the SF-6D index values from the SF-36 data for comparison with the scores obtained with the EQ-5D questionnaire. Results. The SF-6D and EQ-5D provided good sensitivities for detecting disease activity-dependent utility differences. However, the single-measure intraclass correlation coefficient was 0.58, and the Bland-Altman plot indicated numerous values beyond the limits of agreement. Conclusions. There was poor agreement between the measures retrieved from the EQ-5D and the SF-6D utility instruments. Although both instruments may provide good sensitivity for the detection of disease activity-dependent utility differences, the instruments cannot be used interchangeably. Cost-utility analyses performed with only one utility instrument must be interpreted with caution.

  9. Ozone-depleting substances and the greenhouse gases HFCs, PFCs and SF{sub 6}. Danish consumption and emissions, 2006

    Energy Technology Data Exchange (ETDEWEB)

    Sander Poulsen, T. (PlanMiljoe (Denmark))

    2007-07-01

    The objective of this project was to map the 2006 consumption of newly produced industrial ozone-depleting substances and the consumption and actual emissions of HFCs, PFCs, and SF{sub 6}. The evaluation was made in accordance with the IPCC guidelines and following the method employed in previous evaluations. (BA)

  10. Design of Hydraulic Bushing and Vehicle Testing for Reducing the Judder Vibration

    Directory of Open Access Journals (Sweden)

    Kim Youngman

    2018-01-01

    Full Text Available Generally, judder vibration is a low-frequency vibration phenomenon caused by a braking force imbalance that occurs when a vehicle is lightly decelerated within a range of 0.1 to 0.2g at a speed of 120 to 60 km/h. This comes from the change in the brake disk thickness (DTV, which is mainly caused by the side run-out (SRO and thermal deformation. The adoption of hydro-bushing in the low arm G bushings of the vehicle front suspension has been done in order to provide great damping in a particular frequency range (<20Hz in order to prevent this judder vibration from being transmitted to the body. The hydro bushing was formulated using a lumped parameter model. The fluid passage between the two chambers was modelled as a nonlinear element such as an orifice, and its important parameters (resistance, compliance were measured using a simplified experimental setup. The main design parameters are the ratio of the cross-sectional area of the chamber to the fluid passage, the length of the fluid passage, etc., and their optimal design is such that the loss angle is greater than 45 ° in the target frequency range of 10 to 20 Hz. The hydro bushing designed for reducing the judder vibration was prepared for the actual vehicle application test and applied to the actual vehicle test. In this study, the proposed hydro bushing was applied to the G bushing of the low arm of the front suspension system of the vehicle. The loss angle of the manufactured hydro bushing was measured using acceleration signals before and after passing through the bushing. The actual vehicle test was performed on the noise dynamometer for the performance analysis of the judder vibration reduction.

  11. Theoretical and experimental studies of N and SF2 reaction

    International Nuclear Information System (INIS)

    Yu Shuqin; Zhou Xiaoguo

    2000-02-01

    In this paper, free radical reaction of N+SF 2 induced by dc discharge in N 2 and SF 6 system was examined. Although the NS + (m/z = 46) ion signals were detected, NS + is not the spectral carrier from obtained REMPI spectra analysis. Ab initio quantum calculation shows that NSF is the main product of N + SF 2 . It is confirmed from this calculation that NS + obtained in experiment was produced by multiphoton ionization and dissociation of NSF which is real product of N + SF 2 reaction. (author)

  12. The Bush administration climate proposal: rhetoric and reality

    Energy Technology Data Exchange (ETDEWEB)

    Blanchard, O.

    2003-03-01

    This paper examines the Bush administration proposal and subsequent actions in terms of the United Nations Framework Convention on Climate Change (UNFCCC). It has four sections. Section one describes the main features of the Bush Administration climate proposal. Section 2 identifies the main underlying factors that shape this proposal. Section 3 rebuts the Administration critique in deciding to reject the Kyoto protocol. Section 4 explores the prospects of the US climate mitigation actions over the next few years. (A.L.B.)

  13. New model of universal gas-filled neutron tube

    International Nuclear Information System (INIS)

    Bespalov, D.F.; Bessarabskii, I.G.; Voitsik, L.R.; Mints, A.Z.

    1985-01-01

    The UNG-1 gas-filled neutron tube is serially produced. In type UNG neutron generators, the tube operates in the pulsed mode in the high voltage doubling circuit arrangement. During extended operation, its advantages were discovered: long operating time, fairly stable neutron yield, and simplicity of use and operation. However, the mean neutron yield (approx.10 7 s -1 ) generated by the tube in the optimal mode at the present time proved to be inadequate in solving numerous geophysical problems. So a model of a neutron tube, model UNG-2, was designed, ensuring an enhanced neutron yield of 10 8 s -1 in the continuous-operating mode. When the tube is connected to the high voltage doubling circuit, the mean neutron yield is only somewhat in excess of the neutron yield from the UNG-1 tube

  14. Short Form-McGill Pain Questionnaire-2 (SF-MPQ-2: A Cross-Cultural Adaptation and Validation Study of the Persian Version in Patients with Knee Osteoarthritis

    Directory of Open Access Journals (Sweden)

    Amir Reza Kachooei

    2015-01-01

    Full Text Available Background: We aimed to develop and validate the Persian version of Short Form McGill Pain Questionnaire-2 (SF-MPQ-2 in patients with knee osteoarthritis. Methods: Translation and back translation was performed using Beaton’s guideline. After a consensus has achieved on the Persian version of SF-MPQ-2, it was administered to 30 patients with knee osteoarthritis in a pilot study. Then, we enrolled 100 patients with knee osteoarthritis to fill the final SF-MPQ-2 as well as SF-36 and WOMAC questionnaires. Forty-three patients returned 3 days after the initial visit to fill the Persian SF-MPQ-2 for the second time. Construct validity was tested by Pearson’s correlation coefficient between subscales of SF-MPQ-2 and subscales of SF-36 and WOMAC. Internal consistency for total and subscales was calculated by Cronbach’s alpha and reliability between test retest was performed using Intraclass correlation coefficient (ICC. Results: ICC for subscales of SF-MPQ-2 ranged from 0.73 to 0.90. The ICC for total SF-MPQ-2 was 0.90. Cronbach’s alpha for subscales was 0.65-0.74 at the first visit and 0.58-0.81 at the second visit. Cronbach’s alpha for the total questionnaire was 0.88 and 0.91 at the first and second visit, respectively. Pearson’s correlation coefficient was highly significant when comparing subscales specifically with WOMAC (r=-0.47 to -0.61; P

  15. Short Form-McGill Pain Questionnaire-2 (SF-MPQ-2: A Cross-Cultural Adaptation and Validation Study of the Persian Version in Patients with Knee Osteoarthritis

    Directory of Open Access Journals (Sweden)

    Amir Reza Kachooei

    2015-01-01

    Background: We aimed to develop and validate the Persian version of Short Form McGill Pain Questionnaire-2 (SF-MPQ-2 in patients with knee osteoarthritis. Methods: Translation and back translation was performed using Beaton’s guideline. After a consensus has achieved on the Persian version of SF-MPQ-2, it was administered to 30 patients with knee osteoarthritis in a pilot study. Then, we enrolled 100 patients with knee osteoarthritis to fill the final SF-MPQ-2 as well as SF-36 and WOMAC questionnaires. Forty-three patients returned 3 days after the initial visit to fill the Persian SF-MPQ-2 for the second time. Construct validity was tested by Pearson’s correlation coefficient between subscales of SF-MPQ-2 and subscales of SF-36 and WOMAC. Internal consistency for total and subscales was calculated by Cronbach’s alpha and reliability between test retest was performed using Intraclass correlation coefficient (ICC. Results: ICC for subscales of SF-MPQ-2 ranged from 0.73 to 0.90. The ICC for total SF-MPQ-2 was 0.90. Cronbach’s alpha for subscales was 0.65-0.74 at the first visit and 0.58-0.81 at the second visit. Cronbach’s alpha for the total questionnaire was 0.88 and 0.91 at the first and second visit, respectively. Pearson’s correlation coefficient was highly significant when comparing subscales specifically with WOMAC (r=-0.47 to -0.61; P

  16. The George W. Bush administration: a new environment?

    International Nuclear Information System (INIS)

    Jalonick, M.C.

    2004-05-01

    Bush rejection of the Kyoto protocol and refusal to regulate carbon dioxide emissions was one of many moves that has been unpopular with American environmentalists. In the last four years, they have criticized Bush and his administration for pushing changes to clean air law, forestry policy and endangered species laws. The administration has also come under fire for proposals to drill for oil in sensitive lands. These groups have found some potent allies in Congress, including some moderate Republicans, and in the states. Supporters of Bush environmental initiatives, including most Republican congressional leaders, industry groups and conservative organizations, have called his policy balanced and say that he brings a ''common sense'' approach to industry regulation. These two sides have found little in common in the last four years, and have compromised on almost nothing. As a result, the environment, once a bi-partisan issue, has become more and more a polarizing one. (author)

  17. Acoustically modulated magnetic resonance imaging of gas-filled protein nanostructures

    Science.gov (United States)

    Lu, George J.; Farhadi, Arash; Szablowski, Jerzy O.; Lee-Gosselin, Audrey; Barnes, Samuel R.; Lakshmanan, Anupama; Bourdeau, Raymond W.; Shapiro, Mikhail G.

    2018-05-01

    Non-invasive biological imaging requires materials capable of interacting with deeply penetrant forms of energy such as magnetic fields and sound waves. Here, we show that gas vesicles (GVs), a unique class of gas-filled protein nanostructures with differential magnetic susceptibility relative to water, can produce robust contrast in magnetic resonance imaging (MRI) at sub-nanomolar concentrations, and that this contrast can be inactivated with ultrasound in situ to enable background-free imaging. We demonstrate this capability in vitro, in cells expressing these nanostructures as genetically encoded reporters, and in three model in vivo scenarios. Genetic variants of GVs, differing in their magnetic or mechanical phenotypes, allow multiplexed imaging using parametric MRI and differential acoustic sensitivity. Additionally, clustering-induced changes in MRI contrast enable the design of dynamic molecular sensors. By coupling the complementary physics of MRI and ultrasound, this nanomaterial gives rise to a distinct modality for molecular imaging with unique advantages and capabilities.

  18. More light on the 2ν5 Raman overtone of SF6: Can a weak anisotropic spectrum be due to a strong transition anisotropy?

    Science.gov (United States)

    Kremer, D.; Rachet, F.; Chrysos, M.

    2014-01-01

    Long known as a fully polarized band with a near vanishing depolarization ratio [ηs = 0.05, W. Holzer and R. Ouillon, Chem. Phys. Lett. 24, 589 (1974)], the 2ν5 Raman overtone of SF6 has so far been considered as of having a prohibitively weak anisotropic spectrum [D. P. Shelton and L. Ulivi, J. Chem. Phys. 89, 149 (1988)]. Here, we report the first anisotropic spectrum of this overtone, at room temperature and for 13 gas densities ranging between 2 and 27 amagat. This spectrum is 10 times broader and 50 times weaker than the isotropic counterpart of the overtone [D. Kremer, F. Rachet, and M. Chrysos, J. Chem. Phys. 138, 174308 (2013)] and its profile much more sensitive to pressure effects than the profile of the isotropic spectrum. From our measurements an accurate value for the anisotropy matrix-element |⟨000020|Δα|000000⟩| was derived and this value was found to be comparable to that of the mean-polarizability | |. Among other conclusions our study offers compelling evidence that, in Raman spectroscopy, highly polarized bands or tiny depolarization ratios are not necessarily incompatible with large polarizability anisotropy transition matrix-elements. Our findings and the way to analyze them suggest that new strategies should be developed on the basis of the complementarity inherent in independent incoherent Raman experiments that run with two different incident-beam polarizations, and on concerted efforts to ab initio calculate accurate data for first and second polarizability derivatives. Values for these derivatives are still rarities in the literature of SF6.

  19. Simulations of viscous and compressible gas-gas flows using high-order finite difference schemes

    Science.gov (United States)

    Capuano, M.; Bogey, C.; Spelt, P. D. M.

    2018-05-01

    A computational method for the simulation of viscous and compressible gas-gas flows is presented. It consists in solving the Navier-Stokes equations associated with a convection equation governing the motion of the interface between two gases using high-order finite-difference schemes. A discontinuity-capturing methodology based on sensors and a spatial filter enables capturing shock waves and deformable interfaces. One-dimensional test cases are performed as validation and to justify choices in the numerical method. The results compare well with analytical solutions. Shock waves and interfaces are accurately propagated, and remain sharp. Subsequently, two-dimensional flows are considered including viscosity and thermal conductivity. In Richtmyer-Meshkov instability, generated on an air-SF6 interface, the influence of the mesh refinement on the instability shape is studied, and the temporal variations of the instability amplitude is compared with experimental data. Finally, for a plane shock wave propagating in air and impacting a cylindrical bubble filled with helium or R22, numerical Schlieren pictures obtained using different grid refinements are found to compare well with experimental shadow-photographs. The mass conservation is verified from the temporal variations of the mass of the bubble. The mean velocities of pressure waves and bubble interface are similar to those obtained experimentally.

  20. Comparison of the Multiattribute Utility Instruments EQ-5D and SF-6D in a Europe-Wide Population-Based Cohort of Patients with Inflammatory Bowel Disease 10 Years after Diagnosis

    Directory of Open Access Journals (Sweden)

    Gert Huppertz-Hauss

    2016-01-01

    Full Text Available Background. The treatment of chronic inflammatory bowel disease (IBD is costly, and limited resources call for analyses of the cost effectiveness of therapeutic interventions. The present study evaluated the equivalency of the Short Form 6D (SF-6D and the Euro QoL (EQ-5D, two preference-based HRQoL instruments that are broadly used in cost-effectiveness analyses, in an unselected IBD patient population. Methods. IBD patients from seven European countries were invited to a follow-up visit ten years after their initial diagnosis. Clinical and demographic data were assessed, and the Short Form 36 (SF-36 was employed. Utility scores were obtained by calculating the SF-6D index values from the SF-36 data for comparison with the scores obtained with the EQ-5D questionnaire. Results. The SF-6D and EQ-5D provided good sensitivities for detecting disease activity-dependent utility differences. However, the single-measure intraclass correlation coefficient was 0.58, and the Bland-Altman plot indicated numerous values beyond the limits of agreement. Conclusions. There was poor agreement between the measures retrieved from the EQ-5D and the SF-6D utility instruments. Although both instruments may provide good sensitivity for the detection of disease activity-dependent utility differences, the instruments cannot be used interchangeably. Cost-utility analyses performed with only one utility instrument must be interpreted with caution.

  1. Laser absorption, power transfer, and radiation symmetry during the first shock of inertial confinement fusion gas-filled hohlraum experiments

    International Nuclear Information System (INIS)

    Pak, A.; Dewald, E. L.; Landen, O. L.; Milovich, J.; Strozzi, D. J.; Berzak Hopkins, L. F.; Bradley, D. K.; Divol, L.; Ho, D. D.; MacKinnon, A. J.; Meezan, N. B.; Michel, P.; Moody, J. D.; Moore, A. S.; Schneider, M. B.; Town, R. P. J.; Hsing, W. W.; Edwards, M. J.

    2015-01-01

    Temporally resolved measurements of the hohlraum radiation flux asymmetry incident onto a bismuth coated surrogate capsule have been made over the first two nanoseconds of ignition relevant laser pulses. Specifically, we study the P2 asymmetry of the incoming flux as a function of cone fraction, defined as the inner-to-total laser beam power ratio, for a variety of hohlraums with different scales and gas fills. This work was performed to understand the relevance of recent experiments, conducted in new reduced-scale neopentane gas filled hohlraums, to full scale helium filled ignition targets. Experimental measurements, matched by 3D view factor calculations, are used to infer differences in symmetry, relative beam absorption, and cross beam energy transfer (CBET), employing an analytic model. Despite differences in hohlraum dimensions and gas fill, as well as in laser beam pointing and power, we find that laser absorption, CBET, and the cone fraction, at which a symmetric flux is achieved, are similar to within 25% between experiments conducted in the reduced and full scale hohlraums. This work demonstrates a close surrogacy in the dynamics during the first shock between reduced-scale and full scale implosion experiments and is an important step in enabling the increased rate of study for physics associated with inertial confinement fusion

  2. Laser absorption, power transfer, and radiation symmetry during the first shock of inertial confinement fusion gas-filled hohlraum experiments

    Science.gov (United States)

    Pak, A.; Dewald, E. L.; Landen, O. L.; Milovich, J.; Strozzi, D. J.; Berzak Hopkins, L. F.; Bradley, D. K.; Divol, L.; Ho, D. D.; MacKinnon, A. J.; Meezan, N. B.; Michel, P.; Moody, J. D.; Moore, A. S.; Schneider, M. B.; Town, R. P. J.; Hsing, W. W.; Edwards, M. J.

    2015-12-01

    Temporally resolved measurements of the hohlraum radiation flux asymmetry incident onto a bismuth coated surrogate capsule have been made over the first two nanoseconds of ignition relevant laser pulses. Specifically, we study the P2 asymmetry of the incoming flux as a function of cone fraction, defined as the inner-to-total laser beam power ratio, for a variety of hohlraums with different scales and gas fills. This work was performed to understand the relevance of recent experiments, conducted in new reduced-scale neopentane gas filled hohlraums, to full scale helium filled ignition targets. Experimental measurements, matched by 3D view factor calculations, are used to infer differences in symmetry, relative beam absorption, and cross beam energy transfer (CBET), employing an analytic model. Despite differences in hohlraum dimensions and gas fill, as well as in laser beam pointing and power, we find that laser absorption, CBET, and the cone fraction, at which a symmetric flux is achieved, are similar to within 25% between experiments conducted in the reduced and full scale hohlraums. This work demonstrates a close surrogacy in the dynamics during the first shock between reduced-scale and full scale implosion experiments and is an important step in enabling the increased rate of study for physics associated with inertial confinement fusion.

  3. Laser absorption, power transfer, and radiation symmetry during the first shock of inertial confinement fusion gas-filled hohlraum experiments

    Energy Technology Data Exchange (ETDEWEB)

    Pak, A.; Dewald, E. L.; Landen, O. L.; Milovich, J.; Strozzi, D. J.; Berzak Hopkins, L. F.; Bradley, D. K.; Divol, L.; Ho, D. D.; MacKinnon, A. J.; Meezan, N. B.; Michel, P.; Moody, J. D.; Moore, A. S.; Schneider, M. B.; Town, R. P. J.; Hsing, W. W.; Edwards, M. J. [Lawrence Livermore National Laboratory, Livermore, California, 94550 (United States)

    2015-12-15

    Temporally resolved measurements of the hohlraum radiation flux asymmetry incident onto a bismuth coated surrogate capsule have been made over the first two nanoseconds of ignition relevant laser pulses. Specifically, we study the P2 asymmetry of the incoming flux as a function of cone fraction, defined as the inner-to-total laser beam power ratio, for a variety of hohlraums with different scales and gas fills. This work was performed to understand the relevance of recent experiments, conducted in new reduced-scale neopentane gas filled hohlraums, to full scale helium filled ignition targets. Experimental measurements, matched by 3D view factor calculations, are used to infer differences in symmetry, relative beam absorption, and cross beam energy transfer (CBET), employing an analytic model. Despite differences in hohlraum dimensions and gas fill, as well as in laser beam pointing and power, we find that laser absorption, CBET, and the cone fraction, at which a symmetric flux is achieved, are similar to within 25% between experiments conducted in the reduced and full scale hohlraums. This work demonstrates a close surrogacy in the dynamics during the first shock between reduced-scale and full scale implosion experiments and is an important step in enabling the increased rate of study for physics associated with inertial confinement fusion.

  4. Thermophysical and radiation properties of high-temperature C4F8-CO2 mixtures to replace SF6 in high-voltage circuit breakers

    Science.gov (United States)

    Zhong, Linlin; Cressault, Yann; Teulet, Philippe

    2018-03-01

    C4F8-CO2 mixtures are one of the potential substitutes to SF6 in high-voltage circuit breakers. However, the arc quenching ability of C4F8-CO2 mixtures is still unknown. In order to provide the necessary basic data for the further investigation of arc quenching performance, the compositions, thermodynamic properties, transport coefficients, and net emission coefficients (NEC) of various C4F8-CO2 mixtures are calculated at temperatures of 300-30 000 K in this work. The thermodynamic properties are presented as the product of mass density and specific heat, i.e., ρCp. The transport coefficients include electrical conductivity, viscosity, and thermal conductivity. The atomic and molecular radiation are both taken into account in the calculation of NEC. The comparison of the properties between SF6 and C4F8-CO2 mixtures is also discussed to find their differences. The results of compositions show that C4F8-CO2 mixtures have a distinctive advantage over other alternative gases e.g., CF3I and C3F8, because the dissociative product (i.e., C4F6) of C4F8 at low temperatures has a very high dielectric strength. This is good for an arc quenching medium to endure the arc recovery phase. Compared with SF6, C4F8-CO2 mixtures present lower ρCp at temperatures below 2800 K and larger thermal conductivity above 2800 K. Based on the position of peaks in thermal conductivity, we predict that the cooling of C4F8-CO2 arc will be slowed down at higher temperatures than that of SF6 arc. It is also found that the mixing of CO2 shows slight effects on the electrical conductivity and NEC of C4F8-CO2 mixtures.

  5. Age dating and flow path evaluation of groundwater by SF6 and microbe in the foot of Mt. Fuji, central Japan

    Science.gov (United States)

    Yamamoto, Chisato; Tsujimura, Maki; Kato, Kenji; Nagaosa, Kazuyo; Sakakibara, Koichi; Umei, Yohei; Ohara, Kazuma

    2016-04-01

    A variety of industries are developed at the foot of volcanic mountains in Japan and the groundwater is major source for industrial activity in those regions. The age of groundwater has been estimated to be from 10 to 30 years in Mt. Fuji regions by using 36Cl and 3H. However, the age has not been evaluated using SF6 with higher time resolution in these regions. Also, the total number of prokaryotes shows a specific value in each spring water, suggesting different path and age of the groundwater. Therefore, we aim to estimate residence time and the groundwater flow in three dimensions using the multi-tracers approach; CFCs, SF6, the total number of prokaryotes, the stable isotopes of oxygen-18, deuterium. We collected totally 25 spring water samples in Mt. Fuji and analyzed concentration of inorganic ions, the stable isotopes of oxygen-18, deuterium, CFCs, SF6. The apparent age of the spring water was estimated to be ranging from 4 to 19 years at the foot of Mt. Fuji. These results are reasonable as considering the existed age data by36Cl (Tosaki, 2008) in this region. The spring water with younger age tends to show higher total number of prokaryotes, suggesting that the groundwater flows dominantly through the shallow and young lava with the higher total number of prokaryotes, leads to younger age. Focusing on a specific spring water, the seasonal change of SF6 and total number of prokaryotes were monitored. The spring water showed a younger age and higher total number of prokaryotes during the high water flow season, whereas it showed an older age and lower total number of prokaryotes. Therefore, the total number of prokaryotes shows a good negative correlation with the residence time of the spring/ groundwater in space and time. This shows a possibility that the total number of prokaryotes could be a useful tracer of groundwater for time and space in the three dimensions information.

  6. Mechanical strength and hydrophobicity of cotton fabric after SF6 plasma treatment

    Science.gov (United States)

    Kamlangkla, K.; Paosawatyanyong, B.; Pavarajarn, V.; Hodak, Jose H.; Hodak, Satreerat K.

    2010-08-01

    Surface treatments to tailor fabric properties are in high demand by the modern garment industry. We studied the effect of radio-frequency inductively coupled SF plasma on the surface characteristics of cotton fabric. The duration of the treatment and the SF pressure were varied systematically. We measured the hydrophobicity of treated cotton as a function of storage time and washing cycles. We used the weight loss (%) along with the etching rate, the tensile strength, the morphology changes and the hydrophobicity of the fabric as observables after treatments with different plasma conditions. The weight loss remains below 1% but it significantly increases when the treatment time is longer than 5 min. Substantial changes in the surface morphology of the fiber are concomitant with the increased etching rate and increased weight loss with measurable consequences in their mechanical characteristics. The measured water absorption time reaches the maximum of 210 min when the SF pressure is higher than 0.3 Torr. The water contact angle ( 149°) and the absorption time (210 min) of cotton treated with extreme conditions appear to be durable as long as the fabric is not washed. X-ray photoelectron spectroscopy analysis reveals that the water absorption time of the fabric follows the same increasing trend as the fluorine/carbon ratio at the fabric surface and atom density of fluorine measured by Ar actinometer.

  7. A Comparison of SF-36 and SF-12 Composite Scores and Subsequent Hospitalization and Mortality Risks in Long-Term Dialysis Patients

    Science.gov (United States)

    Xu, Jianglin; Lin, Shu-Fang; Dean, Sandie Guerra; Lazarus, J. Michael; Hakim, Raymond M.

    2010-01-01

    Background and objectives: The Short Form 12 (SF-12) has not been validated for long-term dialysis patients. The study compared physical and mental component summary (PCS/MCS) scores from the SF-36 with those from the embedded SF-12 in a national cohort of dialysis patients. Design, setting, participants, & measurements: All 44,395 patients who had scorable SF-36 and SF-12 from January 1, 2006, to December 31, 2006, and were treated at Fresenius Medical Care, North America facilities were included. Death and first hospitalization were followed for up to 1 year from the date of survey. Correlation and agreement were obtained between PCS-36 and PCS-12 and MCS-36 and MCS-12; then Cox models were constructed to compare associated hazard ratios (HRs) between them. Results: Physical and mental dimensions both exhibited excellent intraclass correlation coefficients of 0.94. Each incremental point for both PCS-12 and PCS-36 was associated with a 2.4% lower adjusted HR of death and 0.4% decline in HR for first hospitalization (both P < 0.0001). Corresponding improvement in HR of death for each MCS point was 1.2% for MCS-12 and 1.3% for MCS-36, whereas both had similar 0.6% lower HR for hospitalization per point (all P < 0.0001). Conclusions: The use of the SF-12 alone or as part of a larger survey is valid in dialysis patients. Composite scores from the SF-12 and SF-36 have similar prognostic association with death and hospitalization risk. Prospective longitudinal studies of SF-12 surveys that consider responsiveness to specific clinical, situational, and interventional changes are needed in this population. PMID:20019120

  8. Fatigue Analysis of an Outer Bearing Bush of a Kaplan Turbine

    Directory of Open Access Journals (Sweden)

    Doina Frunzaverde

    2011-01-01

    Full Text Available The paper presents the fatigue analysis of an outer bearing bush of aKaplan turbine. This outer bush, together with an inner one, bear thepin lever - trunion - blade subassembly of the runner blade operatingmechanism. For modeling and simulation, SolidWorks software is used.

  9. Pauvreté et politique sociale : le bilan des années Bush  Poverty and Public Policy: An Assessment of the Bush Years

    Directory of Open Access Journals (Sweden)

    Taoufik Djebali

    2010-03-01

    Full Text Available Neuf jours après son investiture, G. W. Bush lançait son programme relatif aux Faith-Based Initiatives (FBI, une partie prenante de son « conservatisme compatissant ». Les FBI constituent une rupture avec la tradition monétariste reaganienne, même si elles s’appuient sur le rejet de l’État et la réduction du budget social. Le rôle des FBI est d’aider les organisations caritatives, notamment religieuses, à s’investir davantage dans le travail social.  Le bilan de la politique sociale de G. Bush est plutôt mitigé. La pauvreté a fortement augmenté et les promesses budgétaires en faveur des Faith-Based Organizations n’ont pas été tenues. Pire, les accusations contre les dérives des FBI fusent. L’administration Bush est accusée d’avoir utilisé les FBI et l’argent public pour obtenir des gains politiques et mettre en place un système de financement occulte en faveur des républicains et leurs alliés.Nine days after he was sworn in, Bush launched his social program, the Faith-Based Initiatives (FBI, a major component of his “compassionate conservatism.” The FBI constituted a break with the Reagan monetarist tradition, even if they are motivated by the withdrawal of the State and the reduction of the social budget. The role of the FBI is to help charities, in particular religious organizations, to invest more in social work. On the whole, the social policy implemented during the Bush years is evaluated negatively. Poverty increased rapidly and the financial promises in favor of the Faith-Based Organizations were not kept. Worse, new revelations have been disclosed. The Bush administration is accused of having used the FBI and public money to make political gains and set up an obscure funding system that benefited the Republicans and their political allies.

  10. Gas Sensing Analysis of Ag-Decorated Graphene for Sulfur Hexafluoride Decomposition Products Based on the Density Functional Theory

    Directory of Open Access Journals (Sweden)

    Xiaoxing Zhang

    2016-11-01

    Full Text Available Detection of decomposition products of sulfur hexafluoride (SF6 is one of the best ways to diagnose early latent insulation faults in gas-insulated equipment, and the occurrence of sudden accidents can be avoided effectively by finding early latent faults. Recently, functionalized graphene, a kind of gas sensing material, has been reported to show good application prospects in the gas sensor field. Therefore, calculations were performed to analyze the gas sensing properties of intrinsic graphene (Int-graphene and functionalized graphene-based material, Ag-decorated graphene (Ag-graphene, for decomposition products of SF6, including SO2F2, SOF2, and SO2, based on density functional theory (DFT. We thoroughly investigated a series of parameters presenting gas-sensing properties of adsorbing process about gas molecule (SO2F2, SOF2, SO2 and double gas molecules (2SO2F2, 2SOF2, 2SO2 on Ag-graphene, including adsorption energy, net charge transfer, electronic state density, and the highest and lowest unoccupied molecular orbital. The results showed that the Ag atom significantly enhances the electrochemical reactivity of graphene, reflected in the change of conductivity during the adsorption process. SO2F2 and SO2 gas molecules on Ag-graphene presented chemisorption, and the adsorption strength was SO2F2 > SO2, while SOF2 absorption on Ag-graphene was physical adsorption. Thus, we concluded that Ag-graphene showed good selectivity and high sensitivity to SO2F2. The results can provide a helpful guide in exploring Ag-graphene material in experiments for monitoring the insulation status of SF6-insulated equipment based on detecting decomposition products of SF6.

  11. An in-situ nano-scale swelling-filling strategy to improve overall performance of Nafion membrane for direct methanol fuel cell application

    Science.gov (United States)

    Li, Jing; Fan, Kun; Cai, Weiwei; Ma, Liying; Xu, Guoxiao; Xu, Sen; Ma, Liang; Cheng, Hansong

    2016-11-01

    A novel in-situ nano-scale swelling-filling (SF) strategy is proposed to modify commercial Nafion membranes for performance enhancement of direct methanol fuel cells (DMFCs). A Nafion membrane was filled in-situ with proton conductive macromolecules (PCMs) in the swelling process of a Nafion membrane in a PCM solution. As a result, both proton conductivity and methanol-permeation resistivity of the SF-treated Naifion membrane was substantially improved with the selectivity nearly doubled compared to the original Nafion membrane. The mechanical strength of the optimal SF treated Nafion membrane was also enforced due to the strong interaction between the PCM fillers and the Nafion molecular chains. As a result, a DMFC equipped with the SF-treated membrane yielded a 33% higher maximum power density than that offered by the DMFC with the original Nafion membrane.

  12. Broadband high-resolution multi-species CARS in gas-filled hollow-core photonic crystal fiber.

    Science.gov (United States)

    Trabold, Barbara M; Hupfer, Robert J R; Abdolvand, Amir; St J Russell, Philip

    2017-09-01

    We report the use of coherent anti-Stokes Raman spectroscopy (CARS) in gas-filled hollow-core photonic crystal fiber (HC-PCF) for trace gas detection. The long optical path-lengths yield a 60 dB increase in the signal level compared with free-space arrangements. This enables a relatively weak supercontinuum (SC) to be used as Stokes seed, along with a ns pump pulse, paving the way for broadband (>4000  cm -1 ) single-shot CARS with an unprecedented resolution of ∼100  MHz. A kagomé-style HC-PCF provides broadband guidance, and, by operating close to the pressure-tunable zero dispersion wavelength, we can ensure simultaneous phase-matching of all gas species. We demonstrate simultaneous measurement of the concentrations of multiple trace gases in a gas sample introduced into the core of the HC-PCF.

  13. Contributions on Computer Aided Manufacturing of Drill-Jig Bushings

    Directory of Open Access Journals (Sweden)

    Vasile Cojocaru

    2009-01-01

    Full Text Available The paper presents the steps for computer aided manufacturing (CAMof the bushings technological class parts: design of the part in CADsoftware; generation of the parametrical link with MSExcel files; extract of the useful information for the technological design (mass, volume, surfaces; setting of the CNC lathe and necessary tools; programming of the CNC code for manufacturing. Given the large variety of the bushingsshapes and dimensions, the application focused on the jig bushings used in drilling processes.

  14. Conductive core of radiation-resistant high-pressure electric bushing, especially for nuclear technology

    International Nuclear Information System (INIS)

    Zajic, V.

    1981-01-01

    A radiation-resistant high-pressure electric bushing was developed featuring a conductive core consisting of a hollow moulding. At the point of attachment to the bushing insulator the core moulding is widened, thus forming a ring support of a diameter larger by at least 10% than the diameter of the conductive core cylindrical section. On the outer side of the pressure body the core cavity is narrowed and tightly closed with the conductor. On the side facing the medium of higher pressure, the conductive core is provided with a thread. Core manufacture and connection of the conductor to the bushing is very simple. The bushing can be used for an environment with pressures exceeding 10 MPa. (J.B.)

  15. Conductive core of radiation-resistant high-pressure electric bushing, especially for nuclear technology

    Energy Technology Data Exchange (ETDEWEB)

    Zajic, V

    1981-09-01

    A radiation-resistant high-pressure electric bushing was developed featuring a conductive core consisting of a hollow moulding. At the point of attachment to the bushing insulator the core moulding is widened, thus forming a ring support of a diameter larger by at least 10% than the diameter of the conductive core cylindrical section. On the outer side of the pressure body the core cavity is narrowed and tightly closed with the conductor. On the side facing the medium of higher pressure, the conductive core is provided with a thread. Core manufacture and connection of the conductor to the bushing is very simple. The bushing can be used for an environment with pressures exceeding 10 MPa.

  16. Simulation of Stress Distribution in a Thick- Walled Bushing Produced by Die-Casting

    Directory of Open Access Journals (Sweden)

    Pisarek B.P.

    2017-12-01

    Full Text Available Metallographic investigations and a computer simulation of stresses in a gravity die-casting bushing were performed. Simulation of the casting process, solidification of the thick-walled bushing and calculations of the stress was performed using MAGMA5.3 software. The size variability of phases κII affecting the formation of phase stresses σf, depending on the location of the metallographic test area, was identified. The distribution of thermal σt and shrinkage stresses σs, depending on the location of the control point SC in the bushing's volume, was estimated. Probably the nature of these stresses will change slightly even after machining. This can cause variations in operating characteristics (friction coefficient, wear. Due to the strong inhomogeneity of the stress distribution in the bushing's casting, it is necessary to perform further tests of the possibility to conduct thermal treatment guaranteeing homogenization of the internal stresses in the casting, as well as to introduce changes in the bushing' s construction and the casting technology. The paper presents the continuation of the results of research aimed at identifying the causes of defects in the thick-walled bushing, die-casting made of CuAl10Fe5Ni5Cr aluminium bronze.

  17. Chemical compositions and antimicrobial activities of Athrixia phylicoides DC. (bush tea), Monsonia burkeana (special tea) and synergistic effects of both combined herbal teas.

    Science.gov (United States)

    Tshivhandekano, Itani; Ntushelo, Khayalethu; Ngezimana, Wonder; Tshikalange, Thilivhali Emmanuel; Mudau, Fhatuwani Nixwell

    2014-09-01

    To determine the chemical compositions and evaluate the antimicrobial activity of bush tea (Athrixia phylicoides DC.), special tea (Monsonia burkeana) and synergy (combination of bush tea and special tea). Total polyphenols were determined using the methods reported by Singleton and Rossi (1965) and modified by Waterman and Mole (1994). Tannins were determined using vanillin HCL methods described by Prince et al. (1978). Total antioxidants were determined using the methods described by Awika et al. (2004). The micro dilution technique using 96-well micro-plates, as described by Eloff (1998) was used to obtain the minimum inhibition concentration (MIC) and minimum microbicidal concentration (MMC) values of the ethanol extracts against the microorganisms under study. The microbes strain used was Gram negative bacteria such as Escherichia coli, Klebsiella oxytoca, Proteus vulgaris, Serratia marcescens, Salmonella typhi, Klebsiella pneumonia; Gram positive bacteria such as Bacillus cereus, Staphylococcus aureus and a fungus Candida albicans. The results demonstrated that special tea contains significantly higher content of total polyphenols (8.34 mg/100 g) and total antioxidant (0.83 mg/100 g) as compared to bush tea [total polyphenols (6.41 mg/100g) and total antioxidant (0.63 mg/100g)] and combination of bush tea and special tea [total polyphenols (6.42 mg/100 g) and total antioxidant (0.64 mg/100 g)]. There was no significant difference in tannins between bush tea, special tea and synergy. The results of antimicrobial activity (MIC and MMC) demonstrated that the ethanol extracts of bush tea, special tea and synergy possessed antimicrobial activity against all microorganisms at different zones. The MIC of bush tea ranged from 1.56 to 12.50 mg/mL while the MMC ranged from 0.78 to 12.50 mg/mL. Special tea's MIC ranged from 0.39 to 12.50 mg/mL while the MMC ranged from 0.01 to 12.50 mg/mL. The MIC of synergy ranged from 3.13 to 12.50 mg/mL while the MMC ranged from 3

  18. Naine kohtub Hundiga - püüne peal / Kaja Kann, Bush Hartshorn

    Index Scriptorium Estoniae

    Kann, Kaja, 1973-

    2006-01-01

    Kanuti Gildi saalis etendub 26.-28. veebr. Kaja Kanni ja Bush Hartshorni lavaduett "Naine ja Hunt". Autorid räägivad, kuidas nad käisid Pärnumaa laantes oma lavaloole õiget tunnetust otsimas. Lisatud andmed Bush Hartshorni kohta

  19. More light on the 2ν5 Raman overtone of SF6: Can a weak anisotropic spectrum be due to a strong transition anisotropy?

    International Nuclear Information System (INIS)

    Kremer, D.; Rachet, F.; Chrysos, M.

    2014-01-01

    Long known as a fully polarized band with a near vanishing depolarization ratio [η s = 0.05, W. Holzer and R. Ouillon, Chem. Phys. Lett. 24, 589 (1974)], the 2ν 5 Raman overtone of SF 6 has so far been considered as of having a prohibitively weak anisotropic spectrum [D. P. Shelton and L. Ulivi, J. Chem. Phys. 89, 149 (1988)]. Here, we report the first anisotropic spectrum of this overtone, at room temperature and for 13 gas densities ranging between 2 and 27 amagat. This spectrum is 10 times broader and 50 times weaker than the isotropic counterpart of the overtone [D. Kremer, F. Rachet, and M. Chrysos, J. Chem. Phys. 138, 174308 (2013)] and its profile much more sensitive to pressure effects than the profile of the isotropic spectrum. From our measurements an accurate value for the anisotropy matrix-element |〈000020|Δα|000000〉| was derived and this value was found to be comparable to that of the mean-polarizability ((000020), α ¯ (000000)). Among other conclusions our study offers compelling evidence that, in Raman spectroscopy, highly polarized bands or tiny depolarization ratios are not necessarily incompatible with large polarizability anisotropy transition matrix-elements. Our findings and the way to analyze them suggest that new strategies should be developed on the basis of the complementarity inherent in independent incoherent Raman experiments that run with two different incident-beam polarizations, and on concerted efforts to ab initio calculate accurate data for first and second polarizability derivatives. Values for these derivatives are still rarities in the literature of SF 6

  20. Polystyrene foam products equation of state as a function of porosity and fill gas

    International Nuclear Information System (INIS)

    Mulford, Roberta N.; Swift, Damian C.

    2009-01-01

    An accurate EOS for polystyrene foam is necessary for analysis of numerous experiments in shock compression, inertial confinement fusion, and astrophysics. Plastic to gas ratios vary between various samples of foam, according to the density and cell-size of the foam. A matrix of compositions has been investigated, allowing prediction of foam response as a function of the plastic-to-air ratio. The EOS code CHEETAH allows participation of the air in the decomposition reaction of the foam. Differences between air-filled, Ar-blown, and CO 2 -blown foams are investigated, to estimate the importance of allowing air to react with products of polystyrene decomposition. O 2 -blown foams are included in some comparisons, to amplify any consequences of reaction with oxygen in air. He-blown foams are included in some comparisons, to provide an extremum of density. Product pressures are slightly higher for oxygen-containing fill gases than for non-oxygen-containing fill gases. Examination of product species indicates that CO 2 decomposes at high temperatures.

  1. BiCMOS amplifier-discriminator integrated circuit for gas-filled detector readout

    International Nuclear Information System (INIS)

    Herve, C.; Dzahini, D.; Le Caer, T.; Richer, J.-P.; Torki, K.

    2005-01-01

    The paper presents a 16-channel amplifier-discriminator designed in BiCMOS technology. It will be used for the binary parallel readout of gas-filled detectors being designed at the European Synchrotron Radiation Facility. The circuit (named AMS211) has been manufactured. The measured transimpedance gain (400 KΩ), bandwidth (25 MHz) and noise (1570 e - +95 e - /pF ENC) well match the simulated results. The discriminator thresholds are individually controlled by built-in Digital to Analogue Converter. The experience gained with a first prototype of readout electronics indicates that the AMS211 should meet our requirements

  2. BiCMOS amplifier-discriminator integrated circuit for gas-filled detector readout

    Energy Technology Data Exchange (ETDEWEB)

    Herve, C. [European Synchrotron Radiation Facility, BP 220, 38043 Grenoble Cedex (France)]. E-mail: herve@esrf.fr; Dzahini, D. [Laboratoire de Physique Subatomique et de Cosmologie, Grenoble (France); Le Caer, T. [European Synchrotron Radiation Facility, BP 220, 38043 Grenoble Cedex (France); Richer, J.-P. [Laboratoire de Physique Subatomique et de Cosmologie, Grenoble (France); Torki, K. [Laboratoire TIMA, Grenoble (France)

    2005-03-21

    The paper presents a 16-channel amplifier-discriminator designed in BiCMOS technology. It will be used for the binary parallel readout of gas-filled detectors being designed at the European Synchrotron Radiation Facility. The circuit (named AMS211) has been manufactured. The measured transimpedance gain (400 K{omega}), bandwidth (25 MHz) and noise (1570 e{sup -}+95 e{sup -}/pF ENC) well match the simulated results. The discriminator thresholds are individually controlled by built-in Digital to Analogue Converter. The experience gained with a first prototype of readout electronics indicates that the AMS211 should meet our requirements.

  3. Angle-resolved photoemission spectroscopy with 9-eV photon-energy pulses generated in a gas-filled hollow-core photonic crystal fiber

    OpenAIRE

    Bromberger, H.; Ermolov, A.; Belli, F.; Liu, H.; Calegari, F.; Chavez-Cervantes, M.; Li, M. T.; Lin, C. T.; Abdolvand, A.; Russell, P. St. J.; Cavalleri, A.; Travers, J. C.; Gierz, I.

    2015-01-01

    A recently developed source of ultraviolet radiation, based on optical soliton propagation in a gas-filled hollow-core photonic crystal fiber, is applied here to angle-resolved photoemission spectroscopy (ARPES). Near-infrared femtosecond pulses of only few {\\mu}J energy generate vacuum ultraviolet (VUV) radiation between 5.5 and 9 eV inside the gas-filled fiber. These pulses are used to measure the band structure of the topological insulator Bi2Se3 with a signal to noise ratio comparable to ...

  4. Generation of multiple VUV dispersive waves using a tapered gas-filled hollow-core anti-resonant fiber

    DEFF Research Database (Denmark)

    Habib, Md Selim; Markos, Christos; Bang, Ole

    2017-01-01

    Hollow-core anti-resonant (HC-AR) fibers are perhaps the best platform for ultrafast nonlinear optics based on light-gas interactions because they offer broadband guidance and low-loss guidance. The main advantage of using gases inside HC fibers is that both the dispersion and nonlinearity can...... be tuned by simply changing the pressure of the gas [1]. The emission of efficient dispersive wave (DW) in the deep-UV has been already observed in a uniform Ar-filled hollow-core fiber with tunability from 200 to 320 nm by changing the gas pressure and pulse energy [2]. In the quest of optimizing...

  5. Application of desirability function for optimizing the performance characteristics of carbonitrided bushes

    Directory of Open Access Journals (Sweden)

    Boby John

    2013-06-01

    Full Text Available The performance of a product is generally characterized by more than one response variable. Hence the management often faces the problem of simultaneous optimization of many response variables. This study was undertaken to simultaneously optimize the surface hardness and case depth of carbonitrided bushes. Even though lots of literature has been published on various methodologies for tackling the multi-response optimization problem, the simultaneous optimization of heat treated properties of carbonitrided bushes are not reported yet. In this research the effect of four factors and two interactions on surface hardness and case depth of carbontirded bushes were studied using design of experiments. Based on the experimental results, the expected values of the heat treated properties of the bushes were estimated for all possible combination of factors. Then the best combination which, simultaneously optimized the response variables, was arrived at using desirability function. The study showed that the optimum combination obtained through desirability function approach not only minimized the variation around the targets of surface hardness and case depth but also was superior to the ones obtained by optimizing the response variables separately. Moreover this study provides a useful and effective approach to design the production process to manufacture bushes with customer specified surface hardness and case depth targets.

  6. Bush favours research at Pentagon and NIH

    CERN Multimedia

    MacIlwain, C

    2001-01-01

    The first budget from George W. Bush increases funding for military research and the NIH, while environmental work is drastically cut. The rest of civilian science funding is essentially frozen (1 page).

  7. The Invasive Buddleja Daviddi (Butterfly Bush)

    Science.gov (United States)

    Buddleja davidii Franchet (Synonym. Buddleia davidii; common name butterfly bush) is a perennial, semi-deciduous, multi-stemmed shrub that is resident in gardens and disturbed areas. Since its introduction to the United Kingdom from China in the late 1800s, B. davidii has become...

  8. Growth arrest specific protein (GAS) 6

    DEFF Research Database (Denmark)

    Haase, T N; Rasmussen, Morten; Jaksch, C A M

    2013-01-01

    using RNA microarray and quantitative PCR. The role of a differentially expressed gene, growth arrest specific protein 6 (GAS6), was evaluated in vitro using neonatal rat islets. Results The mRNA level of Gas6, known to be mitogenic in other tissues, was reduced in LP offspring. The mRNA content of Mafa...... was increased in LP offspring suggesting an early maturation of beta cells. When applied in vitro, GAS6 increased proliferation of neonatal pancreatic beta cells, while reducing glucose-stimulated insulin secretion without changing the total insulin content of the islets. In addition, GAS6 decreased the m......RNA content of Mafa. Conclusions/interpretation We propose a role for GAS6 in the regulation of pancreatic beta cells in the critical period around the time of birth. Our results support the hypothesis that the reduced beta cell mass seen in LP offspring is caused by a change in the intra-uterine environment...

  9. Adding Some Gas Can Completely Change How an Object in a Liquid-Filled Housing Responds to Vibration

    Science.gov (United States)

    Torczynski, J. R.; O'Hern, T. J.; Clausen, J. R.

    2015-11-01

    Adding a little gas can completely change the motion of an object in a liquid-filled housing during vibration. A common system exhibiting this behavior is a spring-supported piston in a liquid-filled cylinder, where the gaps between them are narrow and depend on the piston position. When gas is absent, the piston's vibrational response is highly overdamped due to forcing viscous liquid through narrow gaps. When a small amount of gas is added, Bjerknes forces cause some of the gas to migrate below the piston. The resulting two gas regions form a pneumatic spring that enables the liquid to move with the piston, with the result that very little liquid is forced through the narrow gaps. This ``Couette mode'' has low damping and thus has a strong resonance near the frequency given by the pneumatic spring constant and the piston mass. At this frequency, the piston response is large, and the nonlinearity from the gap geometry produces a net force on the piston. This ``rectified'' force can be many times the piston's weight and can cause the piston to compress its supporting spring. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  10. Correlations between transmembrane 4 L6 family member 5 (TM4SF5, CD151, and CD63 in liver fibrotic phenotypes and hepatic migration and invasive capacities.

    Directory of Open Access Journals (Sweden)

    Minkyung Kang

    Full Text Available Transmembrane 4 L6 family member 5 (TM4SF5 is overexpressed during CCl4-mediated murine liver fibrosis and in human hepatocellular carcinomas. The tetraspanins form tetraspanin-enriched microdomains (TEMs consisting of large membrane protein complexes on the cell surface. Thus, TM4SF5 may be involved in the signal coordination that controls liver malignancy. We investigated the relationship between TM4SF5-positive TEMs with liver fibrosis and tumorigenesis, using normal Chang hepatocytes that lack TM4SF5 expression and chronically TGFβ1-treated Chang cells that express TM4SF5. TM4SF5 expression is positively correlated with tumorigenic CD151 expression, but is negatively correlated with tumor-suppressive CD63 expression in mouse fibrotic and human hepatic carcinoma tissues, indicating cooperative roles of the tetraspanins in liver malignancies. Although CD151 did not control the expression of TM4SF5, TM4SF5 appeared to control the expression levels of CD151 and CD63. TM4SF5 interacted with CD151, and caused the internalization of CD63 from the cell surface into late lysosomal membranes, presumably leading to terminating the tumor-suppressive functions of CD63. TM4SF5 could overcome the tumorigenic effects of CD151, especially cell migration and extracellular matrix (ECM-degradation. Taken together, TM4SF5 appears to play a role in liver malignancy by controlling the levels of tetraspanins on the cell surface, and could provide a promising therapeutic target for the treatment of liver malignancies.

  11. Radiation resistant electrical bushing for high pressures and temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Zajic, V; Banyr, J

    1980-11-15

    The bushing described is characterized by a hollow with a joining member provided inside of at least one of the bushing's electrically conductive core soldered or embedded into a bore in the insulator. Thus, the concentration is limited of the material of the electrically conductive core in the area of the soldered or embedded joint of the support of the electrically conductive core and the insulator, and the resulting force effect is reduced of the difference in thermal dilatations of the materials of the electrically conductive core and the insulator.

  12. Radiation resistant electrical bushing for high pressures and temperatures

    International Nuclear Information System (INIS)

    Zajic, V.; Banyr, J.

    1980-01-01

    The bushing described is characterized by a hollow with a joining member provided inside of at least one of the bushing's electrically conductive core soldered or embedded into a bore in the insulator. Thus, the concentration is limited of the material of the electrically conductive core in the area of the soldered or embedded joint of the support of the electrically conductive core and the insulator, and the resulting force effect is reduced of the difference in thermal dilatations of the materials of the electrically conductive core and the insulator. (J.B.)

  13. Process and device for subdividing a glass tube filled with a radioactive gas

    International Nuclear Information System (INIS)

    Caffarella, T.E.; Radda, G.J.; Watts, D.J.

    1977-01-01

    A process is described for subdividing into individual sealed segments an elongated glass tube coated internally with a luminescent material and filled with a radioactive gas, this tube having a longitudinal axis. It consists in directing a focused laser beam on to the surface of the tube in an ambient atmosphere with a pressure greater than that of the gas in the tube and to create a relative, repetitive and alternating movement between the laser beam and the surface of the tube. This movement is transversal to the longitudinal axis of the tube, so as to heat and soften the tube along a cutting line until the tube divides and presents new ends where it contracts, causing these ends to seal up [fr

  14. Quantitative studies of transfer in vivo of low density, Sf 12-60, and Sf 60-400 lipoproteins between plasma and arterial intima in humans

    International Nuclear Information System (INIS)

    Shaikh, M.; Wootton, R.; Nordestgaard, B.G.; Baskerville, P.; Lumley, J.S.; La Ville, A.E.; Quiney, J.; Lewis, B.

    1991-01-01

    To assess the potential of various plasma lipoprotein classes to contribute to the lipid content of the arterial intima, influx and efflux of these plasma lipoprotein fractions into and from the intima of human carotid arteries were measured in vivo. While low density lipoprotein (LDL) is known to transfer from plasma into the arterial wall, there is less information on the atherogenic potential of lipoproteins of intermediate density (Sf 12-60) or of very low density (Sf 60-400). Aliquots of the same lipoprotein (LDL, Sf 12-60 lipoprotein particles, or Sf 60-400 lipoprotein particles) iodinated with iodine-125 and iodine-131 were injected intravenously 18-29 hours and 3-6 hours, respectively, before elective surgical removal of atheromatous arterial tissue, and the intimal clearance of lipoproteins, lipoprotein influx, and fractional loss of newly entered lipoproteins were calculated. Intimal clearance of Sf 60-400 particles was not detectable (less than 0.3 microliter x hr-1 x cm-2), whereas the average value for both LDL and Sf 12-60 lipoprotein particles was 0.9 microliter x hr-1 x cm-2. Since the fractional loss of newly entered LDL and Sf 12-60 lipoprotein particles was also similar, the results suggest similar modes of entry and exit for these two particles. However, due to lower plasma concentrations of Sf 12-60 lipoproteins as compared with LDL, the mass influx of cholesterol in the Sf 12-60 particles was on the order of one 10th of that in LDL, and that of apolipoprotein B was about one 20th

  15. Operation feedback of hydrogen filling station

    International Nuclear Information System (INIS)

    Pregassame, S.; Barral, K.; Allidieres, L.; Charbonneau, T.; Lacombe, Y.

    2004-01-01

    One of the technical challenges of hydrogen technology is the development of hydrogen infrastructures which satisfy either safety requirements and reliability of filling processes. AIR LIQUIDE realized an hydrogen filling station in Sassenage (France) operational since September 2003. This station is able to fill 3 buses a day up to 350bar by equilibrium with high pressure buffers. In parallel with commercial stations, the group wanted to create a testing ground in real conditions running with several objectives: validate on a full scale bench a simulation tool able to predict the temperature of both gas and cylinder's materials during filling processes; define the best filling procedures in order to reach mass, temperature and filling time targets; analyse the temperature distribution and evolution inside the cylinder; get a general knowledge about hydrogen stations from safety and reliability point of view; operate the first full scale refuelling station in France. The station is also up-graded for 700bar filling from either a liquid hydrogen source or a gas booster, with cold filling possibility. This paper presents the results concerning 350bar filling : thermal effects, optimal filling procedures and influence of parameters such as climatic conditions are discussed. (author)

  16. Elecciones en Estados Unidos: Bush contra Kerry

    Directory of Open Access Journals (Sweden)

    Miguel Ángel Valverde Loya

    2004-12-01

    Full Text Available In November 2004, presidential elections took place in the United States. President George W. Bush, a Republican, confronted Democratic candidate John F. Kerry. A very close race was expected, focusing on the economic situation of the country and national security, but it was the latter the one which prevailed during the campaign, even as significant participation was motivated by the issue of “moral values”. It was thought that due to the closeness of the contest, any of the sides could appeal to judicial tribunals, just like four years before. At the end, President Bush achieved a clear victory; both in the popular vote and the electoral college, and his party increased its majorities in both chambers of Congress.

  17. Remarks by president Bush and president Ilves, June 24, 2007 / George W. Bush, Toomas Hendrik Ilves

    Index Scriptorium Estoniae

    Bush, George W., 1946-

    2007-01-01

    Ameerika Ühendriikide president George W. Bush ja Eesti president Toomas Hendrik Ilves annavad lühiülevaateValge Maja ovaalkabinetis peetud kõnelusest, mille põhiteemadeks olid olukord Afganistanis ja Iraagis, viisavabadus ning küberrünnakud. Vabariigi President töövisiidil Ameerika Ühendriikides 25.-26.06.2007

  18. Rain and contamination tests on HVDC wall bushings with and without RTV coatings

    International Nuclear Information System (INIS)

    Schneider, H.M.; Hall, J.F.; Nellis, C.L.; Low, S.S.; Lorden, D.J.

    1991-01-01

    In this paper results of tests made to determine the ability of room temperature vulcanized (RTV) silicone rubber coatings to improve the performance of HVDC wall bushings are described. The behavior of uncoated full scale ± 500 kV wall bushings is first determined in wetting conditions consisting of nonuniform rain and fog with various amounts of pre-deposited surface contamination. Parameters affecting flashover performance, such as polarity, rain conductivity, and contamination severity are discussed. Results of nonuniform rain tests on an RTV coated wall bushing are reported

  19. IC 630: Piercing the Veil of the Nuclear Gas

    Science.gov (United States)

    Durré, Mark; Mould, Jeremy; Schartmann, Marc; Ashraf Uddin, Syed; Cotter, Garrett

    2017-04-01

    IC 630 is a nearby early-type galaxy with a mass of 6× {10}10 M ⊙ with an intense burst of recent (6 Myr) star formation (SF). It shows strong nebular emission lines, with radio and X-ray emission, which classifies it as an active galactic nucleus (AGN). With VLT-SINFONI and Gemini North-NIFS adaptive optics observations (plus supplementary ANU 2.3 m WiFeS optical IFU observations), the excitation diagnostics of the nebular emission species show no sign of standard AGN engine excitation; the stellar velocity dispersion also indicates that a supermassive black hole (if one is present) is small ({M}\\bullet =2.25× {10}5 {M}⊙ ). The luminosity at all wavelengths is consistent with SF at a rate of about 1-2 M ⊙ yr-1. We measure gas outflows driven by SF at a rate of 0.18 M ⊙ yr-1 in a face-on truncated cone geometry. We also observe a nuclear cluster or disk and other clusters. Photoionization from young, hot stars is the main excitation mechanism for [Fe II] and hydrogen, whereas shocks are responsible for the H2 excitation. Our observations are broadly comparable with simulations where a Toomre-unstable, self-gravitating gas disk triggers a burst of SF, peaking after about 30 Myr and possibly cycling with a period of about 200 Myr.

  20. Polystyrene foam products equation of state as a function of porosity and fill gas

    Energy Technology Data Exchange (ETDEWEB)

    Mulford, Roberta N [Los Alamos National Laboratory; Swift, Damian C [LLNL

    2009-01-01

    An accurate EOS for polystyrene foam is necessary for analysis of numerous experiments in shock compression, inertial confinement fusion, and astrophysics. Plastic to gas ratios vary between various samples of foam, according to the density and cell-size of the foam. A matrix of compositions has been investigated, allowing prediction of foam response as a function of the plastic-to-air ratio. The EOS code CHEETAH allows participation of the air in the decomposition reaction of the foam. Differences between air-filled, Ar-blown, and CO{sub 2}-blown foams are investigated, to estimate the importance of allowing air to react with products of polystyrene decomposition. O{sub 2}-blown foams are included in some comparisons, to amplify any consequences of reaction with oxygen in air. He-blown foams are included in some comparisons, to provide an extremum of density. Product pressures are slightly higher for oxygen-containing fill gases than for non-oxygen-containing fill gases. Examination of product species indicates that CO{sub 2} decomposes at high temperatures.

  1. Bush and Gore Focus on Schools.

    Science.gov (United States)

    Joiner, Lottie L.

    2000-01-01

    In the 2000 presidential race, education seems a top priority for Vice-President Al Gore and Texas Governor George W. Bush. Although both candidates are promising billions of federal-aid dollars to raise standards, many believe they are ignoring factors such as student motivation and funding inequities. (MLH)

  2. Dating of young groundwater using tritium and gaseous tracers (SF6, SF5CF3, CFC-12, H-1301): case study from southern Poland

    Science.gov (United States)

    Rozanski, Kazimierz; Bartyzel, Jakub; Dulinski, Marek; Kuc, Tadeusz; Sliwka, Ireneusz; Mochalski, Pawel; Kania, Jaroslaw; Witczak, Stanislaw

    2013-04-01

    Groundwater is an important source of potable water in many countries. While it covers ca. 50% of the global drinking water needs, in Europe this share is even higher, reaching approximately 70%. Nowadays, this strategic resource is at risk due to anthropogenic pollutants of various nature entering shallow aquifers. Proper management of groundwater resources requires thorough understanding of groundwater dynamics on time scales characteristic for the history of pollutant input to groundwater. The bomb-tritium has been used for several decades now as a tracer of choice to detect recent recharge and to quantify groundwater residence times on time scales extending from several years to several decades. The lumped-parameter modeling was the most often employed approach in this context. Since nowadays atmospheric concentrations of tritium are approaching natural levels in most parts of the world, the usage of this tracer has become more problematic. Therefore, there is a growing interest in alternative indicators of groundwater age in shallow aquifers. Anthropogenic trace gases present in the atmosphere, such as freons (CFC-11, CFC-12, CFC-113) and sulfur hexafluoride (SF6), have been applied in numerous case studies as substitutes of tritium. Here we present the results of a comprehensive study aimed at quantifying mean residence time of groundwater in the recharge area of porous sandy aquifer system located in the southern Poland. The principal economic role of the aquifer, consisting of two water-bearing strata, is to provide potable water for public and private users. The yield of the aquifer is insufficient to meet all the needs and, as a consequence, licensing conflicts arise between water supply companies and industry on the amount of water available for safe exploitation. To quantify residence time distribution (RTD) functions of water parcels arriving at the production wells located in the recharge area of the aquifer, tritium along with several gaseous tracers

  3. Angle-resolved photoemission spectroscopy with 9-eV photon-energy pulses generated in a gas-filled hollow-core photonic crystal fiber

    Science.gov (United States)

    Bromberger, H.; Ermolov, A.; Belli, F.; Liu, H.; Calegari, F.; Chávez-Cervantes, M.; Li, M. T.; Lin, C. T.; Abdolvand, A.; Russell, P. St. J.; Cavalleri, A.; Travers, J. C.; Gierz, I.

    2015-08-01

    A recently developed source of ultraviolet radiation, based on optical soliton propagation in a gas-filled hollow-core photonic crystal fiber, is applied here to angle-resolved photoemission spectroscopy (ARPES). Near-infrared femtosecond pulses of only few μJ energy generate vacuum ultraviolet radiation between 5.5 and 9 eV inside the gas-filled fiber. These pulses are used to measure the band structure of the topological insulator Bi2Se3 with a signal to noise ratio comparable to that obtained with high order harmonics from a gas jet. The two-order-of-magnitude gain in efficiency promises time-resolved ARPES measurements at repetition rates of hundreds of kHz or even MHz, with photon energies that cover the first Brillouin zone of most materials.

  4. Ingledow 500 kV substation : using mixed technology switchgear solutions for replacement

    Energy Technology Data Exchange (ETDEWEB)

    Wallner, C.; Glaubitz, P. [Siemens AG, Munich (Germany); Messinger, T. [British Columbia Transmission Corp., Vancouver, BC (Canada)

    2008-07-01

    The reliability of the 500 kV equipment at the Ingledow substation operated by BC Hydro Transmission System is of critical importance due to the energy interchange with the Bonneville Power Authority in the United States and the major role of the substation in serving the energy needs of British Columbia's densely populated Lower Mainland. Presently, the 500 kV switchyard includes 10 airblast circuit breakers and the associated current transformers which are all approaching their end of service-life. In response to environmental and safety concerns, the British Columbia Transmission Corporation adopted a policy whereby new oil-filled transformers are no longer acceptable, and the replacement of existing oil-filled transformers must be oil-free. The result is that the current transformers must be either bushing-type or sulphur-hexafluoride (SF6) type. The replacement strategies for the substation equipment consider economical, environmental and seismic issues. They have just as strong an influence on the decision process as the technical, operational and reliability aspects for the particular case or switchgear replacement in the transmission system. The Ingledow case demonstrates the advantages of using mixed technology switchgear, with its compact design flowing from gas insulated switchgear (GIS) for replacement of equipment in an outdoor switchyard. The advantages of the MTS in this case offer the possibility of future reconfiguration to improve the system reliability within the existing switchyard space. 3 refs., 5 figs.

  5. Tracer gas diffusion sampling test plan

    International Nuclear Information System (INIS)

    Rohay, V.J.

    1993-01-01

    Efforts are under way to employ active and passive vapor extraction to remove carbon tetrachloride from the soil in the 200 West Area an the Hanford Site as part of the 200 West Area Carbon Tetrachloride Expedited Response Action. In the active approach, a vacuum is applied to a well, which causes soil gas surrounding the well to be drawn up to the surface. The contaminated air is cleaned by passage through a granular activated carbon bed. There are questions concerning the radius of influence associated with application of the vacuum system and related uncertainties about the soil-gas diffusion rates with and without the vacuum system present. To address these questions, a series of tracer gas diffusion sampling tests is proposed in which an inert, nontoxic tracer gas, sulfur hexafluoride (SF 6 ), will be injected into a well, and the rates of SF 6 diffusion through the surrounding soil horizon will be measured by sampling in nearby wells. Tracer gas tests will be conducted at sites very near the active vacuum extraction system and also at sites beyond the radius of influence of the active vacuum system. In the passive vapor extraction approach, barometric pressure fluctuations cause soil gas to be drawn to the surface through the well. At the passive sites, the effects of barometric ''pumping'' due to changes in atmospheric pressure will be investigated. Application of tracer gas testing to both the active and passive vapor extraction methods is described in the wellfield enhancement work plan (Rohay and Cameron 1993)

  6. The Bush Administration's Policy on Haitian Migration

    National Research Council Canada - National Science Library

    Baptista, A. L

    1995-01-01

    ... (notably the French and U S Ambassador). Aristide was allowed to leave for exile, setting up a long-running crisis that spanned both the latter half of the Bush Administration and part of the Clinton Administration's tenure The purpose...

  7. Growth Arrest-Specific 6 (Gas6) and TAM Receptors in Mouse Platelets.

    Science.gov (United States)

    Uras, Fikriye; Küçük, Burhanettin; Bingöl Özakpınar, Özlem; Demir, Ahmet Muzaffer

    2015-03-05

    Growth arrest-specific 6 (Gas6) is a newly discovered vitamin K-dependent protein, which is a ligand for TAM receptors [Tyro3 (Sky), Axl, and Mer] from the tyrosine kinase family. Gas6 knockout mice were resistant to venous and arterial thrombosis. There are contradictory reports on the presence of Gas6 and its receptors in mouse platelets. The objective of this study was to investigate whether Gas6 and its receptors were present in mouse platelets or not. Specific pathogen-free BALB/c male and female mice of 8-10 weeks old and 25-30 g in weight were anesthetized under light ether anesthesia and blood samples were taken from their hearts. RNAs were isolated from isolated platelets, and then mRNAs encoding Gas6 and TAM receptors were detected by reverse transcription-polymerase chain reaction (RT-PCR). Protein concentrations of Gas6 and TAM receptors in platelets were measured by ELISA, but not those of Mer, because of the absence of any commercial ELISA kit for mouse specimens. RT-PCR results indicated the presence of mRNAs encoding Gas6 and Mer in mouse platelets. However, although RT-PCR reactions were performed at various temperatures and cycles, we could not detect the presence of mRNAs encoding Axl and Tyro3 (Sky). Receptor protein levels of Axl and Tyro3 were below the detection limits of the ELISA method. We found the presence of mRNAs encoding Gas6 and the receptor Mer in mouse platelets, but not Axl and Tyro3. Gas6, Axl, and Tyro3 protein levels were below the detection limits of the ELISA. The presence of mRNA is not obvious evidence of protein expression in platelets that have no nucleus or DNA. Further studies are required to clarify the presence of Gas6/TAM receptors in platelets using real-time PCR and more sensitive immunological methods, and future studies on mechanisms will indicate whether the Gas6/TAM pathway is a strategy for treatment of disorders.

  8. Effect of wind and currents on gas exchange in an estuarine system. Final technical report, 1 August 1986-31 July 1987

    International Nuclear Information System (INIS)

    Broecker, W.S.; Ledwell, J.R.; Bopp, R.

    1987-11-01

    The objectives were to develop a non-volatile tracer to use in gas exchange experiments in laterally unconfined systems and to study applications of deliberate tracers in limnology and oceanography. Progress was made on both fronts but work on the development of the non-volatile tracer proved to be more difficult and labor intensive that anticipated so no field experiments using non-volatile tracers was performed as yet. In the search for a suitable non-volatile tracer for an ocean scale gas exchange experiment a tracer was discovered which does not have the required sensitivity for a large scale experiment, but is very easy to analyze and will be well suited for smaller experiments such as gas exchange determinations on rivers and streams. Sulfur hexafluoride, SF 6 , was used successfully as a volatile tracer along with tritium as a non-volatile tracer to study gas exchange rates from a primary stream. This is the first gas exchange experiment in which gas exchange rates were determined on a head water stream where significant groundwater input occurs along the reach. In conjunction with SF 6 , Radon-222 measurements were performed on the groundwater and in the stream. The feasibility of using a combination of SF 6 and radon is being studied to determine groundwater inputs and gas exchange of rates in streams with significant groundwater input without using a non-volatile tracer

  9. pVT-Second Virial Coefficients B(T ), Viscosity η(T ), and Self-Diffusion ρD(T) of the Gases: BF3, CF4, SiF4, CCl4, SiCl4, SF6, MoF6, WF6, UF6, C(CH3)4, and Si(CH3)4 Determined by Means of an Isotropic Temperature-Dependent Potential

    Science.gov (United States)

    Zarkova, L.; Hohm, U.

    2002-03-01

    We present results on self-consistent calculations of second pVT-virial coefficients B(T), viscosity data η(T), and diffusion coefficients ρD(T) for eleven heavy globular gases: boron trifluoride (BF3), carbon tetrafluoride (CF4), silicon tetrafluoride (SiF4), carbon tetrachloride (CCl4), silicon tetrachloride (SiCl4), sulfur hexafluoride (SF6), molybdenum hexafluoride (MoF6), tungsten hexafluoride (WF6), uranium hexafluoride (UF6), tetramethyl methane (C(CH3)4, TMM), and tetramethyl silane (Si(CH3)4, TMS). The calculations are performed mainly in the temperature range between 200 and 900 K by means of isotropic n-6 potentials with temperature-dependent separation rm(T) and potential well depth ɛ(T). The potential parameters at T=0 K (ɛ, rm, n) and the enlargement of the first level radii δ are obtained solving an ill-posed problem of minimizing the squared deviations between experimental and calculated values normalized to their relative experimental error. The temperature dependence of the potential is obtained as a result of the influence of vibrational excitation on binary interactions. This concept of the isotropic temperature-dependent potential (ITDP) is presented in detail where gaseous SF6 will serve as an example. The ITDP is subsequently applied to all other gases. This approach and the main part of the results presented here have already been published during 1996-2000. However, in some cases the data are upgraded due to the recently improved software (CF4, SF6) and newly found experimental data (CF4, SiF4, CCl4, SF6).

  10. The Gore/Bush Records on Higher Education.

    Science.gov (United States)

    Walters, Ronald

    2000-01-01

    Compares the records of presidential candidates George W. Bush and Al Gore on higher education issues and, specifically, those of interest to the Black community. Concludes that Al Gore's record makes him an overall better choice in the 2000 campaign. (DB)

  11. Gas-filled cell as a narrow bandwidth bandpass filter in the VUV wavelength range

    Energy Technology Data Exchange (ETDEWEB)

    Geloni, Gianluca [European XFEL GmbH, Hamburg (Germany); Kocharyan, Vitali; Saldin, Evgeni [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2011-04-15

    We propose a method for spectrally filtering radiation in the VUV wavelength range by means of a monochromator constituted by a cell filled with a resonantly absorbing rare gas. Around particular wavelengths, the gas exhibits narrow-bandwidth absorbing resonances following the Fano profile. In particular, within the photon energy range 60 eV-65 eV, the correlation index of the Fano profiles for the photoionization spectra in Helium is equal to unity, meaning that the minimum of the cross-section is exactly zero. For sufficiently large column density in the gas cell, the spectrum of the incoming radiation will be attenuated by the background cross-section of many orders of magnitude, except for those wavelengths close to the point where the cross-section is zero. Remarkable advantages of a gas monochromator based on this principle are simplicity, efficiency and narrow-bandwidth. A gas monochromator installed in the experimental hall of a VUV SASE FEL facility would enable the delivery of a single-mode VUV laser beam. The design is identical to that of already existing gas attenuator systems for VUV or X-ray FELs. We present feasibility study and exemplifications for the FLASH facility in the VUV regime. (orig.)

  12. A new focal plane detector for the gas-filled separator TASCA

    International Nuclear Information System (INIS)

    Gorshkov, Alexander

    2010-01-01

    Superheavy elements (SHE) exist solely because of enhanced nuclear stability due to shell effects. The production cross sections for the synthesis of SHE decrease continuously, thus, exploration of SHE nuclei is close to the border of present technical limitation. To increase the efficiency and sensitivity in SHE experiments, highly efficient recoil separators with state-of-the-art detection systems are required. In the framework of this thesis, the new focal plane detection system with the dedicated electronics have been developed for the gas-filled recoil separator TASCA at the GSI Helmholtzzentrum for Schwerionenforschung GmbH. The new detection system has been successfully used in recent experiments on synthesis of the E114.

  13. Automation of experiments at Dubna Gas-Filled Recoil Separator

    Science.gov (United States)

    Tsyganov, Yu. S.

    2016-01-01

    Approaches to solving the problems of automation of basic processes in long-term experiments in heavy ion beams of the Dubna Gas-Filled Recoil Separator (DGFRS) facility are considered. Approaches in the field of spectrometry, both of rare α decays of superheavy nuclei and those for constructing monitoring systems to provide accident-free experiment running with highly radioactive targets and recording basic parameters of experiment, are described. The specific features of Double Side Silicon Strip Detectors (DSSSDs) are considered, special attention is paid to the role of boundary effects of neighboring p-n transitions in the "active correlations" method. An example of an off-beam experiment attempting to observe Zeno effect is briefly considered. Basic examples for nuclear reactions of complete fusion at 48Ca ion beams of U-400 cyclotron (LNR, JINR) are given. A scenario of development of the "active correlations" method for the case of very high intensity beams of heavy ions at promising accelerators of LNR, JINR, is presented.

  14. Angle-resolved photoemission spectroscopy with 9-eV photon-energy pulses generated in a gas-filled hollow-core photonic crystal fiber

    Energy Technology Data Exchange (ETDEWEB)

    Bromberger, H., E-mail: Hubertus.Bromberger@mpsd.mpg.de; Liu, H.; Chávez-Cervantes, M.; Gierz, I. [Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg (Germany); Ermolov, A.; Belli, F.; Abdolvand, A.; Russell, P. St. J.; Travers, J. C. [Max Planck Institute for the Science of Light, Günther-Scharowsky-Str. 1, 91058 Erlangen (Germany); Calegari, F. [Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg (Germany); Institute for Photonics and Nanotechnologies, IFN-CNR, Piazza Leonardo da Vinci 32, I-20133 Milano (Italy); Li, M. T.; Lin, C. T. [Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart (Germany); Cavalleri, A. [Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg (Germany); Clarendon Laboratory, Department of Physics, University of Oxford, Parks Rd. Oxford OX1 3PU (United Kingdom)

    2015-08-31

    A recently developed source of ultraviolet radiation, based on optical soliton propagation in a gas-filled hollow-core photonic crystal fiber, is applied here to angle-resolved photoemission spectroscopy (ARPES). Near-infrared femtosecond pulses of only few μJ energy generate vacuum ultraviolet radiation between 5.5 and 9 eV inside the gas-filled fiber. These pulses are used to measure the band structure of the topological insulator Bi{sub 2}Se{sub 3} with a signal to noise ratio comparable to that obtained with high order harmonics from a gas jet. The two-order-of-magnitude gain in efficiency promises time-resolved ARPES measurements at repetition rates of hundreds of kHz or even MHz, with photon energies that cover the first Brillouin zone of most materials.

  15. Angle-resolved photoemission spectroscopy with 9-eV photon-energy pulses generated in a gas-filled hollow-core photonic crystal fiber

    International Nuclear Information System (INIS)

    Bromberger, H.; Liu, H.; Chávez-Cervantes, M.; Gierz, I.; Ermolov, A.; Belli, F.; Abdolvand, A.; Russell, P. St. J.; Travers, J. C.; Calegari, F.; Li, M. T.; Lin, C. T.; Cavalleri, A.

    2015-01-01

    A recently developed source of ultraviolet radiation, based on optical soliton propagation in a gas-filled hollow-core photonic crystal fiber, is applied here to angle-resolved photoemission spectroscopy (ARPES). Near-infrared femtosecond pulses of only few μJ energy generate vacuum ultraviolet radiation between 5.5 and 9 eV inside the gas-filled fiber. These pulses are used to measure the band structure of the topological insulator Bi 2 Se 3 with a signal to noise ratio comparable to that obtained with high order harmonics from a gas jet. The two-order-of-magnitude gain in efficiency promises time-resolved ARPES measurements at repetition rates of hundreds of kHz or even MHz, with photon energies that cover the first Brillouin zone of most materials

  16. Snit: SF frem, NA og EL under spærregrænsen

    DEFF Research Database (Denmark)

    Thomsen, Søren Risbjerg

    2008-01-01

    NYHED: SF fortsætter fremgangen, mens såvel NA som EL er røget under spærregrænsen i det nye vejede snit af meningsmålinger. Udgivelsesdato: 6. januar......NYHED: SF fortsætter fremgangen, mens såvel NA som EL er røget under spærregrænsen i det nye vejede snit af meningsmålinger. Udgivelsesdato: 6. januar...

  17. Gas phase chemical studies of superheavy elements using the Dubna gas-filled recoil separator - Stopping range determination

    International Nuclear Information System (INIS)

    Wittwer, D.; Abdullin, F.Sh.; Aksenov, N.V.; Albin, Yu.V.; Bozhikov, G.A.; Dmitriev, S.N.; Dressler, R.; Eichler, R.; Gaeggeler, H.W.; Henderson, R.A.; Huebener, S.; Kenneally, J.M.; Lebedev, V.Ya.; Lobanov, Yu.V.; Moody, K.J.; Oganessian, Yu.Ts.; Petrushkin, O.V.; Polyakov, A.N.; Piguet, D.; Rasmussen, P.

    2010-01-01

    Currently, gas phase chemistry experiments with heaviest elements are usually performed with the gas-jet technique with the disadvantage that all reaction products are collected in a gas-filled thermalisation chamber adjacent to the target. The incorporation of a physical preseparation device between target and collection chamber opens up the perspective to perform new chemical studies. But this approach requires detailed knowledge of the stopping force (STF) of the heaviest elements in various materials. Measurements of the energy loss of mercury (Hg), radon (Rn), and nobelium (No) in Mylar and argon (Ar) were performed at low kinetic energies of around (40-270) keV per nucleon. The experimentally obtained values were compared with STF calculations of the commonly used program for calculating stopping and ranges of ions in matter (SRIM). Using the obtained data points an extrapolation of the STF up to element 114, eka-lead, in the same stopping media was carried out. These estimations were applied to design and to perform a first chemical experiment with a superheavy element behind a physical preseparator using the nuclear fusion reaction 244 Pu( 48 Ca; 3n) 289 114. One decay chain assigned to an atom of 285 112, the α-decay product of 289 114, was observed.

  18. The development of a gas-filled time-of-flight detector

    International Nuclear Information System (INIS)

    Guan Yongjing; He Ming; Ruan Xiangdong; Wang Huijuan; Wu Shaoyong; Dong Kejun; Lin Min; Yuan Jian; Jiang Shan

    2007-01-01

    A gas-filled time-of-flight (GF-TOF) detector system for isobaric identification has been developed at the AMS facility of the China Institute of Atomic Energy (CIAE). The newly built GF-TOF detector was tested by using a 36 Cl standard sample ( 36 Cl/Cl = 2.88 x 10 -11 ) with the 36 Cl ion energies of 64, 49 and 33 MeV. Time resolutions of 350 ps, 580 ps and 920 ps were obtained for 64, 49 and 33 MeV 36 S, respectively, without gas. 36 Cl and 36 S particles were successfully separated in the TOF spectra from the GF-TOF detector at the three different incident energies. The dependence of time resolution and separation power of GF-TOF method on the incidence energy and the residual energy is discussed. The comparison of separation power for isobars between the GF-TOF method and the ΔE-E method is described. A combination of GF-TOF method and ΔE-E method may further improve the separation power for isobars. The results show that the sensitivity for 36 Cl AMS measurements is 10 -14 at the energy of 33 MeV. Some results obtained with the GF-TOF method are given

  19. Simplified simulation of multicomponent isotope separation by gas centrifuge

    International Nuclear Information System (INIS)

    Guo Zhixiong; Ying Chuntong

    1995-01-01

    The expressions of diffusion equation for multicomponent isotope separation by gas centrifuge are derived by utilizing the simplified diffusion transport vector. A method of radial averaging which was restricted to a binary mixture is extended to multicomponent isotope mixtures by using an iterative scheme. A numerical analysis of tetradic UF 6 or SF 6 gas isotope separation by centrifuge is discussed when a special model of velocity distribution is given. The dependence of mutual separation factor for the components on their molecular weights' difference is obtained. Some aspects of the given model of gas fluid are also discussed

  20. La politique commerciale de George W. Bush : rupture ou continuité ? American Trade Policy under George W. Bush: Continuity or Change?

    Directory of Open Access Journals (Sweden)

    Jean-Baptiste Velut

    2010-03-01

    Full Text Available Cet article se propose de dresser un bilan critique de la politique commerciale du Président George W. Bush. Dans un premier temps, il compare les perspectives idéologiques et les ambitions politiques du leader républicain à celles de son prédécesseur démocrate, Bill Clinton, avant de mettre l’accent sur les nouvelles données du contexte politique et économique des années 2000. Ces éléments introductifs serviront de fondations, d’une part, pour l’étude de la gestion des relations commerciales entre les États-Unis et leurs principaux partenaires économiques, et d’autre part pour l’analyse de la stratégie de « libéralisation compétitive » adoptée par George W. Bush aux niveaux multilatéral, régional et bilatéral. L’objectif est double : déterminer les lignes de rupture et de continuité entre le président républicain et son prédécesseur ; et établir un bilan des principales initiatives commerciales lancées par l’administration Bush dans le but de mieux comprendre les nouveaux défis intérieurs et internationaux auxquels son successeur sera confronté.This article offers a critical assessment of American trade policy under George W. Bush. It begins by comparing his views and political ambitions with those of his Democratic predecessor, Bill Clinton, before highlighting the new political and economic context of the 2000s. These elements provide crucial background, first to study the evolution of America’s relations with its top trading partners and second to analyze the strategy of “competitive liberalization” undertaken by the administration at the multilateral, regional and bilateral levels. This article has two objectives: 1 determining trends of continuity and change between George W. Bush and his predecessor; 2 assessing the trade policy initiatives undertaken by the Republican administration in order to understand the domestic and international challenges with which the next President

  1. George Bush peab sõjalist jõudu viimaseks valikuks / George W. Bush ; interv. Kaarel Kaas

    Index Scriptorium Estoniae

    Bush, George W., 1946-

    2005-01-01

    Ilmunud ka: Põhjarannik 7. mai 2005, lk. 2, Severnoje Poberezhje 7. mai, 2005, lk. 2. USA president George Bush andis 5. mail Valges Majas intervjuu kuuele Euroopa ajakirjanikule. 9. mai pidustustest Moskvas, USA-Läti, Venemaa-Balti riikide suhetest, demokraatiast Venemaal, Ameerika Ühendriikide ning Baltimaade viisarežiimist, vabaduse mõistestst, kinnipeetavate kohtlemisest Guantanamo sõjaväebaasis, relvade kasutamise vajadusest, terrorismist. Vt. samas: Kuidas usutlus võimalikuks sai

  2. Mechanical behavior of cellular borosilicate glass with pressurized Ar-filled closed pores

    International Nuclear Information System (INIS)

    Wang Bo; Matsumaru, Koji; Yang Jianfeng; Fu Zhengyi; Ishizaki, Kozo

    2012-01-01

    High strength borosilicate foams were fabricated by melting glass powder under high-pressure argon gas and subsequent heat treatment of the glass bulk at atmospheric pressure. In the first step, borosilicate glass powder was melted at 1100 °C for 1 h by capsule-free hot isostatic pressing (HIPing) under a high gas pressure of 10–70 MPa. Pressurized Ar-filled spherical pores were introduced into the glass, and argon atoms were dissolved in the glass network structure. The expansion of argon-filled pores and the release of the dissolved Ar gas resulted in the formation of pressurized Ar-filled closed pores by isothermal heat treatment at 800 °C for 10 min. A high porosity of up to 80% with a bimodal distribution of micro-size cells was obtained for the resultant cellular borosilicate glass. By increasing the total gas pressure from 10 to 70 MPa, the compressive strength and the Young’s modulus were increased considerably from 15 to 52 MPa and from 4.1 to 12.6 GPa, respectively, which can be substantially attributed to the high collapse stress from the high enclosed gas pressure. The cellular glass with a high porosity showed a large failure strain under uniaxial compression.

  3. [Soil basal respiration and enzyme activities in the root-layer soil of tea bushes in a red soil].

    Science.gov (United States)

    Yu, Shen; He, Zhenli; Zhang, Rongguang; Chen, Guochao; Huang, Changyong

    2003-02-01

    Soil basal respiration potential, metabolic quotient (qCO2), and activities of urease, invertase and acid phosphomonoesterase were investigated in the root-layer of 10-, 40-, and 90-yr-old tea bushes grown on the same type of red soil. The soil daily basal respiration potential ranged from 36.23 to 58.52 mg.kg-1.d-1, and the potentials in the root-layer of 40- or 90-yr-old were greater than that of 10-yr old tea bushes. The daily qCO2, ranging from 0.30 to 0.68, was in the reverse trend. The activities of test three enzymes changed differently with tea bushes' age. Urease activity in the root-layer of all age tea bushes ranged from 41.48 to 47.72 mg.kg-1.h-1 and slightly decreased with tea bushes' age. Invertase activity was 189.29-363.40 mg.kg-1.h-1 and decreased with tea bushes' age, but its activity in the root-layer of 10-year old tea bushes was significantly greater than that in the root-layer soil of 40- or 90-year old tea bushes. Acid phosphomonoesterase activity (444.22-828.32 mg.kg-1.h-1) increased significantly with tea bushes' age. Soil basal respiration potential, qCO2 and activities of 3 soil enzymes were closely related to soil pH, soil organic carbon, total nitrogen and C/N ratio, total soluble phenol, and microbial biomass carbon, respectively.

  4. Effect of freeze-thaw cycles on greenhouse gas fluxes from peat soils

    Science.gov (United States)

    Oh, H. D.; Rezanezhad, F.; Markelov, I.; McCarter, C. P. R.; Van Cappellen, P.

    2017-12-01

    The ongoing displacement of climate zones by global warming is increasing the frequency and intensity of freeze-thaw cycles in middle and high latitude regions, many of which are dominated by organic soils such as peat. Repeated freezing and thawing of soils changes their physical properties, geochemistry, and microbial community structure, which together govern the biogeochemical cycling of carbon and nutrients. In this presentation, we focus on how freeze-thaw cycles influence greenhouse gas fluxes from peat using a newly developed experimental soil column system that simulates realistic soil temperature profiles during freeze-thaw cycles. We measured the surface and subsurface changes to gas and aqueous phase chemistry to delineate the diffusion pathways and quantify soil greenhouse gas fluxes during freeze-thaw cycles using sulfur hexafluoride (SF6) as a conservative tracer. Three peat columns were assembled inside a temperature controlled chamber with different soil structures. All three columns were packed with 40 cm of undisturbed, slightly decomposed peat, where the soil of two columns had an additional 10 cm layer on top (one with loose Sphagnum moss and one with an impermeable plug). The results indicate that the release of SF6 and CO2 gas from the soil surface was influenced by the recurrent development of a physical ice barrier, which prevented gas exchange between the soil and atmosphere during freezing conditions. With the onset of thawing a pulse of SF6 and CO2 occurred, resulting in a flux of 3.24 and 2095.52 µmol/m2h, respectively, due to the build-up of gases in the liquid-phase pore space during freezing. Additionally, we developed a model to determine the specific diffusion coefficients for each peat column. These data allow us to better predict how increased frequency and intensity of freeze-thaw cycles will affect greenhouse gas emissions in northern peat soils.

  5. Correlated physical and mental health summary scores for the SF-36 and SF-12 Health Survey, V.1

    Directory of Open Access Journals (Sweden)

    Cunningham William E

    2007-09-01

    Full Text Available Abstract Background The SF-36 and SF-12 summary scores were derived using an uncorrelated (orthogonal factor solution. We estimate SF-36 and SF-12 summary scores using a correlated (oblique physical and mental health factor model. Methods We administered the SF-36 to 7,093 patients who received medical care from an independent association of 48 physician groups in the western United States. Correlated physical health (PCSc and mental health (MCSc scores were constructed by multiplying each SF-36 scale z-score by its respective scoring coefficient from the obliquely rotated two factor solution. PCSc-12 and MCSc-12 scores were estimated using an approach similar to the one used to derive the original SF-12 summary scores. Results The estimated correlation between SF-36 PCSc and MCSc scores was 0.62. There were far fewer negative factor scoring coefficients for the oblique factor solution compared to the factor scoring coefficients produced by the standard orthogonal factor solution. Similar results were found for PCSc-12, and MCSc-12 summary scores. Conclusion Correlated physical and mental health summary scores for the SF-36 and SF-12 derived from an obliquely rotated factor solution should be used along with the uncorrelated summary scores. The new scoring algorithm can reduce inconsistent results between the SF-36 scale scores and physical and mental health summary scores reported in some prior studies. (Subscripts C = correlated and UC = uncorrelated

  6. Using Noble Gas Measurements to Derive Air-Sea Process Information and Predict Physical Gas Saturations

    Science.gov (United States)

    Hamme, Roberta C.; Emerson, Steven R.; Severinghaus, Jeffrey P.; Long, Matthew C.; Yashayaev, Igor

    2017-10-01

    Dissolved gas distributions are important because they influence oceanic habitats and Earth's climate, yet competing controls by biology and physics make gas distributions challenging to predict. Bubble-mediated gas exchange, temperature change, and varying atmospheric pressure all push gases away from equilibrium. Here we use new noble gas measurements from the Labrador Sea to demonstrate a technique to quantify physical processes. Our analysis shows that water-mass formation can be represented by a quasi steady state in which bubble fluxes and cooling push gases away from equilibrium balanced by diffusive gas exchange forcing gases toward equilibrium. We quantify the rates of these physical processes from our measurements, allowing direct comparison to gas exchange parameterizations, and predict the physically driven saturation of other gases. This technique produces predictions that reasonably match N2/Ar observations and demonstrates that physical processes should force SF6 to be ˜6% more supersaturated than CFC-11 and CFC-12, impacting ventilation age calculations.

  7. Are decisions using cost-utility analyses robust to choice of SF-36/SF-12 preference-based algorithm?

    Directory of Open Access Journals (Sweden)

    Walton Surrey M

    2005-03-01

    Full Text Available Abstract Background Cost utility analysis (CUA using SF-36/SF-12 data has been facilitated by the development of several preference-based algorithms. The purpose of this study was to illustrate how decision-making could be affected by the choice of preference-based algorithms for the SF-36 and SF-12, and provide some guidance on selecting an appropriate algorithm. Methods Two sets of data were used: (1 a clinical trial of adult asthma patients; and (2 a longitudinal study of post-stroke patients. Incremental costs were assumed to be $2000 per year over standard treatment, and QALY gains realized over a 1-year period. Ten published algorithms were identified, denoted by first author: Brazier (SF-36, Brazier (SF-12, Shmueli, Fryback, Lundberg, Nichol, Franks (3 algorithms, and Lawrence. Incremental cost-utility ratios (ICURs for each algorithm, stated in dollars per quality-adjusted life year ($/QALY, were ranked and compared between datasets. Results In the asthma patients, estimated ICURs ranged from Lawrence's SF-12 algorithm at $30,769/QALY (95% CI: 26,316 to 36,697 to Brazier's SF-36 algorithm at $63,492/QALY (95% CI: 48,780 to 83,333. ICURs for the stroke cohort varied slightly more dramatically. The MEPS-based algorithm by Franks et al. provided the lowest ICUR at $27,972/QALY (95% CI: 20,942 to 41,667. The Fryback and Shmueli algorithms provided ICURs that were greater than $50,000/QALY and did not have confidence intervals that overlapped with most of the other algorithms. The ICUR-based ranking of algorithms was strongly correlated between the asthma and stroke datasets (r = 0.60. Conclusion SF-36/SF-12 preference-based algorithms produced a wide range of ICURs that could potentially lead to different reimbursement decisions. Brazier's SF-36 and SF-12 algorithms have a strong methodological and theoretical basis and tended to generate relatively higher ICUR estimates, considerations that support a preference for these algorithms over the

  8. Surgical management of macular holes: results using gas tamponade alone, or in combination with autologous platelet concentrate, or transforming growth factor beta 2.

    LENUS (Irish Health Repository)

    Minihan, M

    2012-02-03

    BACKGROUND: Vitrectomy and gas tamponade has become a recognised technique for the treatment of macular holes. In an attempt to improve the anatomic and visual success of the procedure, various adjunctive therapies--cytokines, serum, and platelets--have been employed. A consecutive series of 85 eyes which underwent macular hole surgery using gas tamponade alone, or gas tamponade with either the cytokine transforming growth factor beta 2 (TGF-beta 2) or autologous platelet concentrate is reported. METHODS: Twenty eyes had vitrectomy and 20% SF6 gas tamponade; 15 had vitrectomy, 20% SF6 gas, and TGF-beta 2; 50 had vitrectomy, 16% C3F8 gas tamponade, and 0.1 ml of autologous platelet concentrate prepared during the procedure. RESULTS: Anatomic success occurred in 86% of eyes, with 96% of the platelet treated group achieving closure of the macular hole. Visual acuity improved by two lines or more in 65% of the SF6 only group, 33% of those treated with TGF-beta 2 and in 74% of the platelet treated group. In the platelet treated group 40% achieved 6\\/12 or better and 62% achieved 6\\/18 or better. The best visual results were obtained in stage 2 holes. CONCLUSION: Vitrectomy for macular holes is often of benefit and patients may recover good visual acuity, especially early in the disease process. The procedure has a number of serious complications, and the postoperative posturing requirement is difficult. Patients need to be informed of such concerns before surgery.

  9. Camera system considerations for geomorphic applications of SfM photogrammetry

    Science.gov (United States)

    Mosbrucker, Adam; Major, Jon J.; Spicer, Kurt R.; Pitlick, John

    2017-01-01

    The availability of high-resolution, multi-temporal, remotely sensed topographic data is revolutionizing geomorphic analysis. Three-dimensional topographic point measurements acquired from structure-from-motion (SfM) photogrammetry have been shown to be highly accurate and cost-effective compared to laser-based alternatives in some environments. Use of consumer-grade digital cameras to generate terrain models and derivatives is becoming prevalent within the geomorphic community despite the details of these instruments being largely overlooked in current SfM literature. This article is protected by copyright. All rights reserved.A practical discussion of camera system selection, configuration, and image acquisition is presented. The hypothesis that optimizing source imagery can increase digital terrain model (DTM) accuracy is tested by evaluating accuracies of four SfM datasets conducted over multiple years of a gravel bed river floodplain using independent ground check points with the purpose of comparing morphological sediment budgets computed from SfM- and lidar-derived DTMs. Case study results are compared to existing SfM validation studies in an attempt to deconstruct the principle components of an SfM error budget. This article is protected by copyright. All rights reserved.Greater information capacity of source imagery was found to increase pixel matching quality, which produced 8 times greater point density and 6 times greater accuracy. When propagated through volumetric change analysis, individual DTM accuracy (6–37 cm) was sufficient to detect moderate geomorphic change (order 100,000 m3) on an unvegetated fluvial surface; change detection determined from repeat lidar and SfM surveys differed by about 10%. Simple camera selection criteria increased accuracy by 64%; configuration settings or image post-processing techniques increased point density by 5–25% and decreased processing time by 10–30%. This article is protected by copyright. All rights

  10. Magnetic resonance velocity imaging of liquid and gas two-phase flow in packed beds.

    Science.gov (United States)

    Sankey, M H; Holland, D J; Sederman, A J; Gladden, L F

    2009-02-01

    Single-phase liquid flow in porous media such as bead packs and model fixed bed reactors has been well studied by MRI. To some extent this early work represents the necessary preliminary research to address the more challenging problem of two-phase flow of gas and liquid within these systems. In this paper, we present images of both the gas and liquid velocities during stable liquid-gas flow of water and SF(6) within a packing of 5mm spheres contained within columns of diameter 40 and 27 mm; images being acquired using (1)H and (19)F observation for the water and SF(6), respectively. Liquid and gas flow rates calculated from the velocity images are in agreement with macroscopic flow rate measurements to within 7% and 5%, respectively. In addition to the information obtained directly from these images, the ability to measure liquid and gas flow fields within the same sample environment will enable us to explore the validity of assumptions used in numerical modelling of two-phase flows.

  11. ARCPHdb: A comprehensive protein database for SF1 and SF2 helicase from archaea.

    Science.gov (United States)

    Moukhtar, Mirna; Chaar, Wafi; Abdel-Razzak, Ziad; Khalil, Mohamad; Taha, Samir; Chamieh, Hala

    2017-01-01

    Superfamily 1 and Superfamily 2 helicases, two of the largest helicase protein families, play vital roles in many biological processes including replication, transcription and translation. Study of helicase proteins in the model microorganisms of archaea have largely contributed to the understanding of their function, architecture and assembly. Based on a large phylogenomics approach, we have identified and classified all SF1 and SF2 protein families in ninety five sequenced archaea genomes. Here we developed an online webserver linked to a specialized protein database named ARCPHdb to provide access for SF1 and SF2 helicase families from archaea. ARCPHdb was implemented using MySQL relational database. Web interfaces were developed using Netbeans. Data were stored according to UniProt accession numbers, NCBI Ref Seq ID, PDB IDs and Entrez Databases. A user-friendly interactive web interface has been developed to browse, search and download archaeal helicase protein sequences, their available 3D structure models, and related documentation available in the literature provided by ARCPHdb. The database provides direct links to matching external databases. The ARCPHdb is the first online database to compile all protein information on SF1 and SF2 helicase from archaea in one platform. This database provides essential resource information for all researchers interested in the field. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Characteristics and interpretation of fracture-filled gas hydrate: an example from the Ulleung Basin, East Sea of Korea

    Science.gov (United States)

    Lee, Myung Woong; Collett, Timothy S.

    2013-01-01

    Through the use of 2-D and 3-D seismic data, a total of thirteen sites were selected and drilled in the East Sea of Korea in 2010. A suite of logging-while-drilling (LWD) logs was acquired at each site. LWD logs from the UBGH2-3A well indicate significant gas hydrate in clay-bearing sediments including several zones with massive gas hydrate with a bulk density less than 1.0 g/m3 for depths between 5 and 103 m below the sea floor. The UBGH2-3A well was drilled on a seismically identified chimney structure with a mound feature at the sea floor. Average gas hydrate saturations estimated from the isotropic analysis of ring resistivity and P-wave velocity logs are 80 ± 13% and 47 ± 16%, respectively, whereas they are 46 ± 17% and 45 ± 16%, respectively from the anisotropic analysis. Modeling indicates that the upper part of chimney (between 5 and 45 m below sea floor [mbsf]) is characterized by gas hydrate filling near horizontal fractures (7° dip) and the lower part of chimney (between 45 and 103 mbsf) is characterized by gas hydrate filling high angle fractures on the basis of ring resistivity and P-wave velocity. The anisotropic analysis using P40H resistivity (phase shift resistivity at 32 mHz with 40 inch spacing) and the P-wave velocity yields a gas hydrate saturation of 46 ± 15% and 46 ± 15% respectively, similar to those estimated using ring resistivity and P-wave velocity, but with quite different fracture dip angles. Differences in vertical resolution, depth of investigation, and a finite fracture dimension relative to the tool separation appear to contribute to this discrepancy. Forward modeling of anisotropic resistivity and velocity are essential to identify gas hydrate in fractures and to estimate accurate gas hydrate amounts.

  13. Mould and mycotoxin exposure assessment of melon and bush mango seeds, two common soup thickeners consumed in Nigeria.

    Science.gov (United States)

    Ezekiel, Chibundu N; Sulyok, Michael; Somorin, Yinka; Odutayo, Foluke I; Nwabekee, Stella U; Balogun, Afeez T; Krska, Rudolf

    2016-11-21

    An examination of the mould and fungal metabolite pattern in melon and bush mango seeds locally produced in Nigeria was undertaken in order to understand the mycotoxicological risk posed to consumers of both of these important and commonly consumed soup thickeners. The variation in mycotoxin levels in graded categories of both foodstuffs were also determined. Aspergillus, Fusarium, Penicillium, Mucorales and Trichoderma were the recovered fungi from the foodstuffs with Aspergillus species dominating (melon=97.8%; bush mango=89.9%). Among the Aspergillus species identified Aspergillus section Flavi dominated (melon: 72%; bush mango: 57%) and A. flavus, A. parasiticus, A. parvisclerotigenus and A. tamarii were the recovered species. About 56% and 73% of the A. flavus isolates from melon and bush mango seed samples, respectively were aflatoxigenic. Thirty-four and 59 metabolites including notable mycotoxins were found in the melon and bush mango seeds respectively. Mean aflatoxin levels (μg/kg) in melon (aflatoxin B 1 (AFB 1 )=37.5 and total aflatoxins=142) and bush mango seeds (AFB 1 =68.1 and total aflatoxins=61.7) were higher than other mycotoxins, suggesting potential higher exposure for consumer populations. Significantly (p<0.05) higher levels of mycotoxins were found in hand-peeled melon and discoloured bush mango seeds than in machine-peeled melon and non-discoloured seeds except for HT-2 and T-2 toxins which occurred conversely. All melon and bush mango seeds exceeded the 2μg/kg AFB 1 limit whereas all melon and 55% of bush mango seeds exceeded the 4μg/kg total aflatoxin EU limit adopted in Nigeria. This is the first report of (1) mycotoxin co-occurrence in bush mango seeds, (2) cyclopiazonic acid, HT-2 toxin, moniliformin, mycophenolic acid, T-2 toxin and tenuazonic acid occurrence, and (3) mycotoxin exposure assessment of both foodstuffs. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Focal spot size predictions for beam transport through a gas-filled reactor

    International Nuclear Information System (INIS)

    Yu, S.S.; Lee, E.P.; Buchanan, H.L.

    1980-01-01

    Results from calculations of focal spot size for beam transport through a gas-filled reactor are summarized. In the converging beam mode, we find an enlargement of the focal spot due to multiple scattering and zeroth order self-field effects. This enlargement can be minimized by maintaining small reactors together with a careful choice of the gaseous medium. The self-focused mode, on the other hand, is relatively insensitive to the reactor environment, but is critically dependent upon initial beam quality. This requirement on beam quality can be significantly eased by the injection of an electron beam of modest current from the opposite wall

  15. Bush püüdis leevendada tšehhide Vene-hirmu / Arko Olesk

    Index Scriptorium Estoniae

    Olesk, Arko, 1981-

    2007-01-01

    Ilmunud ka: Postimees : na russkom jazõke, 6. juuni 2007, lk. 9. Prahat külastanud USA president George W. Bush kinnitas oma kõnes, et külm sõda on läbi ning Tšehhi ei pea valima USA ja Venemaa sõbraks olemise vahel, samas kritiseeris ta Venemaad demokraatia puudumise pärast. Vt. samas: Poola langetab raketikilbi otsuse pärast Bushi visiiti

  16. Polystyrene Foam EOS as a Function of Porosity and Fill Gas

    Science.gov (United States)

    Mulford, Roberta; Swift, Damian

    2009-06-01

    An accurate EOS for polystyrene foam is necessary for analysis of numerous experiments in shock compression, inertial confinement fusion, and astrophysics. Plastic to gas ratios vary between various samples of foam, according to the density and cell-size of the foam. A matrix of compositions has been investigated, allowing prediction of foam response as a function of the plastic-to-air ratio. The EOS code CHEETAH allows participation of the air in the decomposition reaction of the foam, Differences between air-filled, nitrogen-blown, and CO2-blown foams are investigated, to estimate the importance of allowing air to react with plastic products during decomposition. Results differ somewhat from the conventional EOS, which are generated from values for plastic extrapolated to low densities.

  17. Measurements of gas filled halfraum energetics at the national ignition facility using a single quad

    Energy Technology Data Exchange (ETDEWEB)

    Kline, J.L.; Fernandez, J.C.; Goldman, S.R.; Gautier, D.C.; Hegelich, B.M.; Montgomery, D.S.; Lanier, N.E.; Rose, H.A.; Workman, J.B. [Los Alamos National Laboratory, Los Alamos, NM (United States); Braun, D.; Landen, O.; Niemann, C.; Campbell, K.; Celeste, J.; Dewald, E.; Glenzer, S.; Hinkel, D.; Holder, J.; Kalantar, D.; Kamperschroer, J.; Kimbrough, J.; Kirkwood, R.; Lee, F.D.; MacGowan, B.; MacKinnon, A.; McDonald, J.; Schein, J.; Schneider, M.; Suter, L.; Young, B. [Lawrence Livermore National Lab., CA (United States)

    2006-06-15

    Gas filled halfraum experiments were conducted at the National Ignition Facility which provided an excellent test of the tools needed to understand halfraum energetics in an ignition relevant regime. The experiments used a highly shaped laser pulse and measured large levels of backscattered laser energy. These two components challenge the ability of radiation hydrodynamic simulations to model the experiments. The results show good agreement between experimental measurements and simulations. (authors)

  18. Measurements of gas filled halfraum energetics at the national ignition facility using a single quad

    International Nuclear Information System (INIS)

    Kline, J.L.; Fernandez, J.C.; Goldman, S.R.; Gautier, D.C.; Hegelich, B.M.; Montgomery, D.S.; Lanier, N.E.; Rose, H.A.; Workman, J.B.; Braun, D.; Landen, O.; Niemann, C.; Campbell, K.; Celeste, J.; Dewald, E.; Glenzer, S.; Hinkel, D.; Holder, J.; Kalantar, D.; Kamperschroer, J.; Kimbrough, J.; Kirkwood, R.; Lee, F.D.; MacGowan, B.; MacKinnon, A.; McDonald, J.; Schein, J.; Schneider, M.; Suter, L.; Young, B.

    2006-01-01

    Gas filled halfraum experiments were conducted at the National Ignition Facility which provided an excellent test of the tools needed to understand halfraum energetics in an ignition relevant regime. The experiments used a highly shaped laser pulse and measured large levels of backscattered laser energy. These two components challenge the ability of radiation hydrodynamic simulations to model the experiments. The results show good agreement between experimental measurements and simulations. (authors)

  19. Controls on Gas Hydrate Formation and Dissociation

    Energy Technology Data Exchange (ETDEWEB)

    Miriam Kastner; Ian MacDonald

    2006-03-03

    The main objectives of the project were to monitor, characterize, and quantify in situ the rates of formation and dissociation of methane hydrates at and near the seafloor in the northern Gulf of Mexico, with a focus on the Bush Hill seafloor hydrate mound; to record the linkages between physical and chemical parameters of the deposits over the course of one year, by emphasizing the response of the hydrate mound to temperature and chemical perturbations; and to document the seafloor and water column environmental impacts of hydrate formation and dissociation. For these, monitoring the dynamics of gas hydrate formation and dissociation was required. The objectives were achieved by an integrated field and laboratory scientific study, particularly by monitoring in situ formation and dissociation of the outcropping gas hydrate mound and of the associated gas-rich sediments. In addition to monitoring with the MOSQUITOs, fluid flow rates and temperature, continuously sampling in situ pore fluids for the chemistry, and imaging the hydrate mound, pore fluids from cores, peepers and gas hydrate samples from the mound were as well sampled and analyzed for chemical and isotopic compositions. In order to determine the impact of gas hydrate dissociation and/or methane venting across the seafloor on the ocean and atmosphere, the overlying seawater was sampled and thoroughly analyzed chemically and for methane C isotope ratios. At Bush hill the pore fluid chemistry varies significantly over short distances as well as within some of the specific sites monitored for 440 days, and gas venting is primarily focused. The pore fluid chemistry in the tub-warm and mussel shell fields clearly documented active gas hydrate and authigenic carbonate formation during the monitoring period. The advecting fluid is depleted in sulfate, Ca Mg, and Sr and is rich in methane; at the main vent sites the fluid is methane supersaturated, thus bubble plumes form. The subsurface hydrology exhibits both

  20. IR laser induced reactions: temperature distributions and detection of primary products

    International Nuclear Information System (INIS)

    Bachmann, F.

    1981-12-01

    The products of laser-driven pyrolysis in the gas phase often differ drastically from those of conventional pyrolysis. In this work some reasons for this behaviour are considered. First, temperature distributions in cylindrical cells, filled with SF 6 at low pressure and heated by cw CO 2 laser radiation, are calculated by a simple model. The influence of convection is not taken into account. Comparison of theoretical prediction and corresponding experiments included the temperature-dependent absorption cross section. In the second part we describe a molecular-beam sampling system for real time monitoring of primary products in laser-driven reactions. With this system initial tests were made in nonreacting SF 6 /rare-gas mixtures. The influence of thermal diffusion was indicated by changes in concentration when the laser was switched on and off. A theoretical treatment is given solving the time-dependent heat-conduction and diffusion equation numerically. As an example for reacting systems, the laser-driven pyrolysis of methanol with SF 6 as an absorber was studied. (orig./HT)

  1. Photochemical removal of NpF6 and PuF6 from UF6 gas streams

    International Nuclear Information System (INIS)

    Beitz, J.V.; Williams, C.W.

    1990-01-01

    A novel photochemical method of removing reactive fluorides from UF 6 gas has been discovered. This method reduces generated waste to little more than the volume of the removed impurities, minimizes loss of UF 6 , and can produce a recyclable by-product, fluorine gas. In our new method, impure UF 6 , is exposed to ultraviolet light which dissociates the UF 6 to UF 5 and fluorine atom. Impurities which chemically react with UF 5 are reduced and form solid compounds easily removed from the gas while UF 5 is converted back to UF 6 . Proof-of-concept testing involved UF 6 containing NpF 6 and PuF 6 with CO added as a fluorine atom scavenger. In a single photolysis step, greater than 5000-fold reduction of PuF 6 was demonstrated while reducing NpF 6 by more than 40-fold. This process is likely to remove corrosion and fission product fluorides that are more reactive than UF 6 and has been demonstrated without an added fluorine atom scavenger by periodically removing photogenerated fluorine gas. 44 refs., 3 figs., 2 tabs

  2. Portable optical frequency standard based on sealed gas-filled hollow-core fiber using a novel encapsulation technique

    DEFF Research Database (Denmark)

    Triches, Marco; Brusch, Anders; Hald, Jan

    2015-01-01

    A portable stand-alone optical frequency standard based on a gas-filled hollow-core photonic crystal fiber is developed to stabilize a fiber laser to the 13C2H2 P(16) (ν1 + ν3) transition at 1542 nm using saturated absorption. A novel encapsulation technique is developed to permanently seal...

  3. The modelling of an SF6 arc in a supersonic nozzle: II. Current zero behaviour of the nozzle arc

    International Nuclear Information System (INIS)

    Zhang, Q; Liu, J; Yan, J D; Fang, M T C

    2016-01-01

    The present work (part II) forms the second part of an investigation into the behaviour of SF 6 nozzle arc. It is concerned with the aerodynamic and electrical behaviour of a transient nozzle arc under a current ramp specified by a rate of current decay (d i /d t ) before current zero and a voltage ramp (d V /d t ) after current zero. The five flow models used in part I [1] for cold gas flow and DC nozzle arcs have been applied to study the transient arc at three stagnation pressures ( P 0 ) and two values of d i /d t for the current ramp, representing a wide range of arcing conditions. An analysis of the physical mechanisms encompassed in each flow model is given with an emphasis on the adequacy of a particular model in describing the rapidly varying arc around current zero. The critical rate of rise of recovery voltage (RRRV) is found computationally and compared with test results of Benenson et al [2]. For transient nozzle arcs, the RRRV is proportional to the square of P 0 , rather than to the square root of P 0 for DC nozzle arcs. The physical mechanisms responsible for the strong dependence of RRRV on P 0 have been investigated. The relative merits of the flow models employed are discussed. (paper)

  4. Angular dependence of etch rates in the etching of poly-Si and fluorocarbon polymer using SF6, C4F8, and O2 plasmas

    International Nuclear Information System (INIS)

    Min, Jae-Ho; Lee, Gyeo-Re; Lee, Jin-Kwan; Moon, Sang Heup; Kim, Chang-Koo

    2004-01-01

    The dependences of etch rates on the angle of ions incident on the substrate surface in four plasma/substrate systems that constitute the advanced Bosch process were investigated using a Faraday cage designed for the accurate control of the ion-incident angle. The four systems, established by combining discharge gases and substrates, were a SF 6 /poly-Si, a SF 6 /fluorocarbon polymer, an O 2 /fluorocarbon polymer, and a C 4 F 8 /Si. In the case of SF 6 /poly-Si, the normalized etch rates (NERs), defined as the etch rates normalized by the rate on the horizontal surface, were higher at all angles than values predicted from the cosine of the ion-incident angle. This characteristic curve shape was independent of changes in process variables including the source power and bias voltage. Contrary to the earlier case, the NERs for the O 2 /polymer decreased and eventually reached much lower values than the cosine values at angles between 30 deg. and 70 deg. when the source power was increased and the bias voltage was decreased. On the other hand, the NERs for the SF 6 /polymer showed a weak dependence on the process variables. In the case of C 4 F 8 /Si, which is used in the Bosch process for depositing a fluorocarbon layer on the substrate surface, the deposition rate varied with the ion incident angle, showing an S-shaped curve. These characteristic deposition rate curves, which were highly dependent on the process conditions, could be divided into four distinct regions: a Si sputtering region, an ion-suppressed polymer deposition region, an ion-enhanced polymer deposition region, and an ion-free polymer deposition region. Based on the earlier characteristic angular dependences of the etch (or deposition) rates in the individual systems, ideal process conditions for obtaining an anisotropic etch profile in the advanced Bosch process are proposed

  5. 77 FR 27253 - Proposed Collection, Laura Bush 21st Century Librarian Grant Program Evaluation

    Science.gov (United States)

    2012-05-09

    ... Century Librarian Grant Program Evaluation AGENCY: Institute of Museum and Library Services, National... evaluate and make improvements to the Laura Bush 21st Century Librarian (LB21) Grant Program. The... proposes clearance of the Laura Bush 21st Century Librarian Grant Program Evaluation. The 60-day Notice for...

  6. Developments for transactinide chemistry experiments behind the gas-filled separator TASCA

    Energy Technology Data Exchange (ETDEWEB)

    Even, Julia

    2011-12-13

    Topic of this thesis is the development of experiments behind the gas-filled separator TASCA (TransActinide Separator and Chemistry Apparatus) to study the chemical properties of the transactinide elements. In the first part of the thesis, the electrodepositions of short-lived isotopes of ruthenium and osmium on gold electrodes were studied as model experiments for hassium. From literature it is known that the deposition potential of single atoms differs significantly from the potential predicted by the Nernst equation. This shift of the potential depends on the adsorption enthalpy of therndeposited element on the electrode material. If the adsorption on the electrode-material is favoured over the adsorption on a surface made of the same element as the deposited atom, the electrode potential is shifted to higher potentials. This phenomenon is called underpotential deposition. Possibilities to automatize an electro chemistry experiment behind the gas-filled separator were explored for later studies with transactinide elements. The second part of this thesis is about the in-situ synthesis of transition-metal-carbonyl complexes with nuclear reaction products. Fission products of uranium-235 and californium-249 were produced at the TRIGA Mainz reactor and thermalized in a carbon-monoxide containing atmosphere. The formed volatile metal-carbonyl complexes could be transported in a gas-stream. Furthermore, short-lived isotopes of tungsten, rhenium, osmium, and iridium were synthesised at the linear accelerator UNILAC at GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt. The recoiling fusion products were separated from the primary beam and the transfer products in the gas-filled separator TASCA. The fusion products were stopped in the focal plane of TASCA in a recoil transfer chamber. This chamber contained a carbon-monoxide - helium gas mixture. The formed metal-carbonyl complexes could be transported in a gas stream to various experimental setups. All

  7. Radiation damage: special reference to gas filled radiation detectors

    International Nuclear Information System (INIS)

    Gaur, Sudha; Joshi, Pankaj Kumar; Rathore, Shakuntla

    2012-01-01

    Radiation damage is a term associated with ionizing radiation. In gas filled particle detectors, radiation damage to gases plays an important role in the device's ageing, especially in devices exposed to high intensity radiation, e.g. detector for the large hadrons collide. Ionization processes require energy above 10 eV, while splitting covalent bond in molecules and generating free radical require only 3-4 eV. The electrical discharges initiated by the ionization event by the particles result in plasma populated by large amount of free radical. The highly reactive free radical can recombine back to original molecules, or initiate a chain of free radical polymerization reaction with other molecules, yielding compounds with increasing molecular weight. These high molecular weight compounds then precipitate from gases phase, forming conductive or non-conductive deposits on the electrodes an insulating surfaces of the detector and distorting it's response. Gases containing hydrocarbon quenchers, e.g. argon-methane, are typically sensitive to ageing by polymerization; addition of oxygen tends to lower the ageing rates. Trace amount of silicon oils, present form out gassing of silicon elastomers and especially from traces of silicon lubricant tend to decompose and form deposits of silicon crystals on the surfaces. Gases mixture of argon (or xenon) with CO 2 and optimally also with 2-3 % of oxygen are highly tolerant to high radiation fluxes. The oxygen is added as noble gas with CO 2 has too high transparency for high energy photons; ozone formed from the oxygen is a strong absorber of ultra violet photons. Carbon tetra fluoride can be used as a component of the gas for high-rate detectors; the fluorine radical produced during the operation however limit the choice of materials for the chambers and electrodes (e.g. gold electrodes are required, as the fluorine radicals attack metals, forming fluorides). Addition of carbon tetra fluoride can however eliminate the

  8. Short-Acting Gas Tamponade with Strict Face-Down Posturing for the Treatment of Idiopathic Macular Hole.

    Science.gov (United States)

    Gotzaridis, Stratos; Liazos, Efstathios; Petrou, Petros; Georgalas, Ilias

    2017-01-01

    A retrospective consecutive case series to evaluate the safety and efficacy of 25 gauge pars plana vitrectomy, ILM peeling, 20% SF 6 gas tamponade and strict posturing for the treatment of idiopathic full-thickness macular holes. We report the results of 106 consecutive eyes that underwent standard 25-gauge pars plana vitrectomy, brilliant peel-assisted internal limiting membrane peel, fluid:gas exchange with 20% SF 6 and strict posturing for one week. All patients were followed up at one week, one month, three months, and nine months postoperatively. Biomicroscopy at day 1 and biomicroscopy and OCT at week 1, months 1, 3, and 9 were used to assess macular hole status postoperatively. Pre- and postoperative logMAR visual acuity was compared. The macular hole was closed in 102/106 eyes postoperatively (96.2%). Four eyes showed unclosed macular holes and underwent additional SF 6 intravitreal injection and strict posturing for 10 days. All macular holes were eventually closed without the need of a second surgical procedure. Mean visual acuity improved from 0.63 logMAR preoperatively to 0.39 logMAR postoperatively. One case of retinal toxicity was reported due to accidental intravitreal injection of antibiotic. 25-gauge vitrectomy, ILM peel, and short-acting gas tamponade are highly effective for the treatment of macular holes. Additional intravitreal gas injection followed by strict posturing seems to be a simple and effective treatment for unclosed holes.

  9. Study of Electron Swarm in High Pressure Hydrogen Gas Filled RF Cavities

    International Nuclear Information System (INIS)

    Yonehara, K.; Chung, M.; Jansson, A.; Moretti, A.; Popovic, M.; Tollestrup, A.; Alsharo'a, M.; Johnson, R.P.; Notani, M.; Oka, T.; Wang, H.

    2010-01-01

    A high pressure hydrogen gas filled RF cavity has been proposed for use in the muon collection system for a muon collider. It allows for high electric field gradients in RF cavities located in strong magnetic fields, a condition frequently encountered in a muon cooling channel. In addition, an intense muon beam will generate an electron swarm via the ionization process in the cavity. A large amount of RF power will be consumed into the swarm. We show the results from our studies of the HV RF breakdown in a cavity without a beam and present some results on the resulting electron swarm dynamics. This is preliminary to actual beam tests which will take place late in 2010.

  10. Bush kutsub ühte hoidma / Kaivo Kopli

    Index Scriptorium Estoniae

    Kopli, Kaivo

    2004-01-01

    USA president George W. Bush kutsus liitlasriike hoidma oma väeüksusi Iraagis. Hispaania tulevane peaminister Jose Luis Rodriquez Zapatero lubas Hispaania sõjaväelased Iraagist ära tuua, kui operatsioonide juhtimine ei lähe USA-lt üle ÜRO-le. Vt. samas: Rumsfeld: hispaanlaste asemele tulevad teised

  11. 46 CFR 98.25-65 - Filling density.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Filling density. 98.25-65 Section 98.25-65 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL... § 98.25-65 Filling density. (a) The filling density, or the percent ratio of the liquefied gas that may...

  12. HGF/SF increases number of skin melanocytes but does not alter quality or quantity of follicular melanogenesis.

    Directory of Open Access Journals (Sweden)

    Agnieszka Wolnicka-Glubisz

    Full Text Available Melanins are an important factor determining the vulnerability of mammalian skin to UV radiation and thus to UV-induced skin cancers. Transgenic mice overexpressing hepatocyte growth factor/scatter factor (HGF/SF have extra-follicular dermal melanocytes, notably in the papillary upper dermis, and are susceptible to UV-induced melanoma. Pigmented HGF/SF neonatal mice are more susceptible than albino HGF/SF animals to UVA -induced melanoma, indicating an involvement of melanin in melanoma formation. This raises the question of the effect of transgenic HGF/SF on melanization. We developed a methodology to accurately quantitate both the production of melanin and the efficiency of melanogenesis in normal, and HGF/SF transgenic mice in vivo. Skin and hair shafts of 5 day old and adult (3 week old C57BL/6-HGF/SF and corresponding C57BL/6 wild type mice were investigated by electron paramagnetic resonance spectroscopy (EPR to quantitate melanin, by transmission electron microscopy (TEM for the presence of melanosomes, and by standard histology and by Western blotting and zymography to determine the expression and activity of melanogenesis-related proteins. Eumelanin but no phaeomelanin was detected in transgenic C57BL/6-HGF and C57BL/6 wild type mice. Transgenic HGF/SF overexpression did not change the type of melanin produced in the skin or hair, did not affect the terminal content of melanin production in standard samples of hair and did not influence hair cycle/morphogenesis-related changes in skin thickness. No melanocytes were found in the epidermis and no melanosomes were found in epidermal keratinocytes. HGF/SF transgenic mice thus lack the epidermal melanin UV-protection found in constitutively dark human skin. We conclude that melanocytes in the HGF/SF transgenic mouse, particularly in the papillary dermis, are vulnerable to UVA which interacts with eumelanin but not phaeomelanin to induce melanoma.

  13. The gas-filled counting tube of the PTB - a device for the activity determination of radioactive gases

    International Nuclear Information System (INIS)

    Guenther, E.W.

    1993-08-01

    A measuring device for the activity determination of gaseous radioactive materials (H-3, Kr-85, C-14 O 2 ) has been set up as a PTB primary standard. Samples measured in it or their initial substances are the basis for activity standards. The gaseous samples are introduced directly into the vacuum device. The amount of gas filled can be determined by measuring pressure, volume and temperature. After the gas has been mixed with a counting gas (methane, argon/methane or propane), the count-rates are measured and the activity of the gas calculated. The activity of solid or liquid radioactive substances can also be determined with the device described, if they can be converted into a suitable gas. For this purpose there are additional devices (e.g. for producing hydrogen from water or C-14 O 2 from carbonate). The first models of these devices have been developed and are described. (orig.) [de

  14. A novel wood flour-filled composite based on microfibrillar high-density polyethylene (HDPE)/Nylon-6 blends.

    Science.gov (United States)

    Liu, Hongzhi; Yao, Fei; Xu, Yanjun; Wu, Qinglin

    2010-05-01

    A novel wood flour (WF)-filled composite based on the microfibrillar high-density polyethylene (HDPE) and Nylon-6 co-blend, in which both in situ formed Nylon-6 microfibrils and WF acted as reinforcing elements, was successfully developed using a two-step extrusion method. At the 30wt.% WF loading level, WF-filled composite based on the microfibrillized HDPE/Nylon-6 blend exhibited higher strengths and moduli than the corresponding HDPE-based composite. The incorporation of WF reduced short-term creep response of HDPE matrix and the presence of Nylon-6 microfibrils further contributed to the creep reduction. Copyright 2009 Elsevier Ltd. All rights reserved.

  15. The Invasive Shrub, Buddleja davidii (Butterfl y Bush)

    Science.gov (United States)

    Buddleja davidii Franchet (Synonym. Buddleia davidii; common name Butterfly bush) is a perennial, semi-deciduous shrub or small multi-stemmed tree that is resident in gardens and disturbed areas in temperate locations worldwide. Since its introduction to the United Kingdom from c...

  16. Budgets come first as Bush chooses NASA head

    CERN Multimedia

    Schrope, M

    2001-01-01

    President Bush has nominated a budget expert with no aerospace or scientific background as the agency's administrator. Sean O'Keefe, formerly scrutinized overspending in the International Space Station programme. If appointed, he will have to implement reforms he himself recommended (1/2 page).

  17. Economic efficiency of the use of the bush vegetation from slopes of the ameliorative canals

    International Nuclear Information System (INIS)

    Titov, V.N.

    2009-01-01

    The results of calculations of the economic efficiency of the use of the bush vegetation from slopes of the ameliorative canals for fuel and energy purposes has been presented. The two variants of disposal of bushes are considered burning and conversion into fuel chips. (authors)

  18. Convergent ablation measurements with gas-filled rugby hohlraum on OMEGA

    Science.gov (United States)

    Casner, A.; Jalinaud, T.; Galmiche, D.

    2016-03-01

    Convergent ablation experiments with gas-filled rugby hohlraum were performed for the first time on the OMEGA laser facility. A time resolved 1D streaked radiography of capsule implosion is acquired in the direction perpendicular to hohlraum axis, whereas a 2D gated radiography is acquired at the same time along the hohlraum axis on a x-ray framing camera. The implosion trajectory has been measured for various kinds of uniformly doped ablators, including germanium-doped and silicon-doped polymers (CH), at two different doping fraction (2% and 4% at.). Our experiments aimed also at measuring the implosion performance of laminated capsules. A laminated ablator is constituted by thin alternate layers of un-doped and doped CH. It has been previously shown in planar geometry that laminated ablators could mitigate Rayleigh Taylor growth at ablation front. Our results confirm that the implosion of a capsule constituted with a uniform or laminated ablator behaves similarly, in accordance with post-shot simulations performed with the CEA hydrocode FCI2.

  19. Investigation of Dalton and Amagat's laws for gas mixtures with shock propagation

    Science.gov (United States)

    Wayne, Patrick; Trueba Monje, Ignacio; Yoo, Jason H.; Truman, C. Randall; Vorobieff, Peter

    2016-11-01

    Two common models describing gas mixtures are Dalton's Law and Amagat's Law (also known as the laws of partial pressures and partial volumes, respectively). Our work is focused on determining the suitability of these models to prediction of effects of shock propagation through gas mixtures. Experiments are conducted at the Shock Tube Facility at the University of New Mexico (UNM). To validate experimental data, possible sources of uncertainty associated with experimental setup are identified and analyzed. The gaseous mixture of interest consists of a prescribed combination of disparate gases - helium and sulfur hexafluoride (SF6). The equations of state (EOS) considered are the ideal gas EOS for helium, and a virial EOS for SF6. The values for the properties provided by these EOS are then used used to model shock propagation through the mixture in accordance with Dalton's and Amagat's laws. Results of the modeling are compared with experiment to determine which law produces better agreement for the mixture. This work is funded by NNSA Grant DE-NA0002913.

  20. EFECTO DE LA ALTURA DEL MANGUITO EN UNIONES SOLDADAS EN CAÑERÍAS DE COBRE BUSHING HEIGHT EFFECT IN SOLDERED COPPER PIPE JOINTS

    Directory of Open Access Journals (Sweden)

    Víctor Carmona

    2006-12-01

    Full Text Available Se perforó un tubo de cobre de 28,6 mm de diámetro, por el proceso de taladrado por fluencia térmica (TFT. Se prepararon manguitos de diferentes alturas, haciendo un preperforado con brocas convencionales HSS de diferentes diámetros. Se seleccionaron manguitos de dos alturas diferentes. Se determinó la circularidad de la perforación. Se soldó un tubo cobre de ø 12,7 mm en forma perpendicular a un tubo de cobre de ø 28,6 mm y se determinó la resistencia a la tracción de la unión soldada, para lo cual se diseñó un dispositivo mecánico que fue adaptado en la máquina universal de ensayos. Se hicieron ensayos de microdureza y metalografía de la unión. Se concluyó que el manguito de menor altura es suficiente para que la unión alcance la máxima resistencia.Copper tubes were drilled with thermal flow drilling. Conventional HSS drills diameters were used to make pre drilling holes. Different height bushings were made. Two of the bushing heights were selected. The bushing circularity was measured. A ø 12,7 mm tube was welded perpendicularly on a ø 28,6 mm tube. A especial support device was designed and it was adapted to the Universal Test Machine, to determine the tensile stress of the brazing joint. The micro hardness and metallographic test were made in the brazing zone. As a conclusion the lower height bushing is enough to reach the maximum resistance.

  1. Greaseless Bushings for Hydropower Applications: Program, Testing, and Results

    National Research Council Canada - National Science Library

    Jones, John

    1999-01-01

    ...) bushings at its hydropower and navigation facilities. Products of this type currently on the market, however, were not specifically developed for the high-load, low-speed oscillating operating conditions typical for power-generation machinery...

  2. Morphological Characterization of African Bush Mango trees (Irvingia species) in the Dahomey Gap (West Africa)

    NARCIS (Netherlands)

    Vihotogbe, R.; Berg, van den R.G.; Sosef, M.S.M.

    2013-01-01

    The variation of the morphological characters of bitter and sweet African bush mango trees (Irvingia species) was investigated in the Dahomey Gap which is the West African savannah woodland area separating the Upper and the Lower Guinean rain forest blocks. African bush mangoes have been rated as

  3. Bush skazal ne sovsem to, tshto skazal

    Index Scriptorium Estoniae

    2006-01-01

    USA abivälisminister Euroopa ja Euraasia küsimustes Daniel Fried teatas, et NATO riigid toetavad Gruusia, Moldova ja Aserbaidžaani territoriaalset terviklikkust, kuid ei luba neil seda taastada relva abil. Abiminister selgitab, mida pidas USA president George W. Bush silmas, kui ta avaldas Riia tippkohtumisel toetust Gruusiale tema püüdlustes liituda NATO-ga

  4. WARM MOLECULAR GAS IN LUMINOUS INFRARED GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Lu, N.; Zhao, Y.; Xu, C. K.; Mazzarella, J. M.; Howell, J.; Appleton, P.; Lord, S.; Schulz, B. [Infrared Processing and Analysis Center, California Institute of Technology, MS 100-22, Pasadena, CA 91125 (United States); Gao, Y. [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Armus, L.; Díaz-Santos, T.; Surace, J. [Spitzer Science Center, California Institute of Technology, MS 220-6, Pasadena, CA 91125 (United States); Isaak, K. G. [ESA Astrophysics Missions Division, ESTEC, P.O. Box 299, 2200-AG Noordwijk (Netherlands); Petric, A. O. [Gemini Observatory, 670 N. A' ohoku Place, Hilo, HI 96720 (United States); Charmandaris, V. [Department of Physics, University of Crete, GR-71003 Heraklion (Greece); Evans, A. S. [Department of Astronomy, University of Virginia, 530 McCormick Road, Charlottesville, VA 22904 (United States); Inami, H. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Iwasawa, K. [ICREA and Institut de Ciències del Cosmos (ICC), Universitat de Barcelona (IEEC-UB), Martí i Franquès 1, E-08028 Barcelona (Spain); Leech, J. [Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Sanders, D. B., E-mail: lu@ipac.caltech.edu [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); and others

    2014-06-01

    We present our initial results on the CO rotational spectral line energy distribution (SLED) of the J to J–1 transitions from J = 4 up to 13 from Herschel SPIRE spectroscopic observations of 65 luminous infrared galaxies (LIRGs) in the Great Observatories All-Sky LIRG Survey. The observed SLEDs change on average from one peaking at J ≤ 4 to a broad distribution peaking around J ∼ 6 to 7 as the IRAS 60-to-100 μm color, C(60/100), increases. However, the ratios of a CO line luminosity to the total infrared luminosity, L {sub IR}, show the smallest variation for J around 6 or 7. This suggests that, for most LIRGs, ongoing star formation (SF) is also responsible for a warm gas component that emits CO lines primarily in the mid-J regime (5 ≲ J ≲ 10). As a result, the logarithmic ratios of the CO line luminosity summed over CO (5–4), (6–5), (7–6), (8–7) and (10–9) transitions to L {sub IR}, log R {sub midCO}, remain largely independent of C(60/100), and show a mean value of –4.13 (≡log R{sub midCO}{sup SF}) and a sample standard deviation of only 0.10 for the SF-dominated galaxies. Including additional galaxies from the literature, we show, albeit with a small number of cases, the possibility that galaxies, which bear powerful interstellar shocks unrelated to the current SF, and galaxies, in which an energetic active galactic nucleus contributes significantly to the bolometric luminosity, have their R {sub midCO} higher and lower than R{sub midCO}{sup SF}, respectively.

  5. Jet formation in shock-heavy gas bubble interaction

    Institute of Scientific and Technical Information of China (English)

    Zhi-Gang Zhai; Ting Si; Li-Yong Zou; Xi-Sheng Luo

    2013-01-01

    The influences of the acoustic impedance and shock strength on the jet formation in shock-heavy gas bubble interaction are numerically studied in this work.The process of a shock interacting with a krypton or a SF6 bubble is studied by the numerical method VAS2D.As a validation,the experiments of a SF6 bubble accelerated by a planar shock were performed.The results indicate that,due to the mismatch of acoustic impedance,the way of jet formation in heavy gas bubble with different species is diversified under the same initial condition.With respect to the same bubble,the manner of jet formation is also distinctly different under different shock strengths.The disparities of the acoustic impedance result in different effects of shock focusing in the bubble,and different behaviors of shock wave inside and outside the bubble.The analyses of the wave pattern and the pressure variation indicate that the jet formation is closely associated with the pressure perturbation.Moreover,the analysis of the vorticity deposition,and comparisons of circulation and baroclinic torque show that the baroclinic vorticity also contributes to the jet formation.It is concluded that the pressure perturbation and baroclinic vorticity deposition are the two dominant factors for the jet formation in shock-heavy gas bubble interaction.

  6. Bush asub uue Iraagi-poliitikaga vigu parandama / Kaivo Kopli

    Index Scriptorium Estoniae

    Kopli, Kaivo

    2007-01-01

    USA president George W. Bush tutvustas uut Iraagi-strateegiat. Iraaki saadetakse paarkümmend tuhat USA sõdurit, küsitluse andmeil on 61% ameeriklastest lisasõdurite saatmise vastu. Lisa: USA plaanid Iraagis ja Iraagiga

  7. The Greek version of the Gagging Assessment Scale in children and adolescents: psychometric properties, prevalence of gagging, and the association between gagging and dental fear.

    Science.gov (United States)

    Katsouda, Maria; Provatenou, Efthymia; Arapostathis, Konstantinos; Coolidge, Trilby; Kotsanos, Nikolaos

    2017-03-01

    No studies assessing the association between gagging and dental fear are available in pediatric samples. To assess the psychometric properties of the Greek version of the Gagging Assessment Scale (GAS), to explore the prevalence of gagging, and to evaluate the relationship between gagging and dental fear in a pediatric sample. A total of 849 8- and 14-year-old children filled out a questionnaire consisting of demographic items, the Greek version of the GAS, and the Greek Children's Fear Survey Schedule Dental Subscale (CFSS-DS); the older children also completed the Greek version of the Modified Dental Anxiety Scale (MDAS). The short form of dentist part of the Gagging Problem Assessment (GPA-de-c/SF) was used to objectively assess gagging. A total of 51 children (6.0%) demonstrated gagging on the GPA-de-c/SF. Children rated as gaggers on the GPA-de-c/SF had significantly higher GAS scores. There were no relationships between GPA-de-c/SF and the CFSS-DS or MDAS. The GAS ratings were significantly correlated with the CFSS-DS (rho = 0.420, P fear was correlated with the self-report gagging assessment, but not with the objective gagging assessment. © 2016 BSPD, IAPD and John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. Ion beam characteristics of the controlatron/zetatron family of the gas filled neutron tubes

    Energy Technology Data Exchange (ETDEWEB)

    Berg, R.S.; Shope, L.A.; O' Neal, M.L.; Boers, J.E.; Bickes, R.W. Jr.

    1981-03-01

    A gas filled tube used to produce a neutron flux with the D(T,He/sup 4/)n reaction is described. Deuterium and tritium ions generated in a reflex discharge are extracted and accelerated to 100 keV by means of an accelerator electrode onto a deutero-tritide target electrode. The electrodes are designed to focus the ion beam onto the target. Total tube currents consisting of extracted ions, unsuppressed secondary electrons, and ions generated by interactions with the background gas are typically 100 mA. The characteristics of the extracted ion beam are discussed. Accelerating voltages greater than 50 kV are required to focus the beam through the accelerator aperture for configurations that give beams with the proper energy density onto the target. The perveance of the beam is discussed. Maximum perveance values are 2 to 20 nanopervs. Tube focusing and neutron production characteristics are described.

  9. Structure from Motion (SfM Photogrammetry with Drone Data: A Low Cost Method for Monitoring Greenhouse Gas Emissions from Forests in Developing Countries

    Directory of Open Access Journals (Sweden)

    Reason Mlambo

    2017-03-01

    Full Text Available Structure from Motion (SfM photogrammetry applied to photographs captured from Unmanned Aerial Vehicle (UAV platforms is increasingly being utilised for a wide range of applications including structural characterisation of forests. The aim of this study was to undertake a first evaluation of whether SfM from UAVs has potential as a low cost method for forest monitoring within developing countries in the context of Reducing Emissions from Deforestation and forest Degradation (REDD+. The project evaluated SfM horizontal and vertical accuracy for measuring the height of individual trees. Aerial image data were collected for two test sites; Meshaw (Devon, UK and Dryden (Scotland, UK using a Quest QPOD fixed wing UAV and DJI Phantom 2 quadcopter UAV, respectively. Comparisons were made between SfM and airborne LiDAR point clouds and surface models at the Meshaw site, while at Dryden, SfM tree heights were compared to ground measured tree heights. Results obtained showed a strong correlation between SfM and LiDAR digital surface models (R2 = 0.89 and canopy height models (R2 = 0.75. However, at Dryden, a poor correlation was observed between SfM tree heights and ground measured heights (R2 = 0.19. The poor results at Dryden were explained by the fact that the forest plot had a closed canopy structure such that SfM failed to generate enough below-canopy ground points. Finally, an evaluation of UAV surveying methods was also undertaken to determine their usefulness and cost-effectiveness for plot-level forest monitoring. The study concluded that although SfM from UAVs performs poorly in closed canopies, it can still provide a low cost solution in those developing countries where forests have sparse canopy cover (<50% with individual tree crowns and ground surfaces well-captured by SfM photogrammetry. Since more than half of the forest covered areas of the world have canopy cover <50%, we can conclude that SfM has enormous potential for forest mapping in

  10. Light energy transmission and Vickers hardness ratio of bulk-fill resin based composites at different thicknesses cured by a dual-wave or a single-wave light curing unit.

    Science.gov (United States)

    Santini, Ario; Naaman, Reem Khalil; Aldossary, Mohammed Saeed

    2017-04-01

    To quantify light energy transmission through two bulk-fill resin-based composites and to measure the top to bottom surface Vickers hardness ratio (VHratio) of samples of various incremental thicknesses, using either a single-wave or dual-wave light curing unit (LCU). Tetric EvoCeram Bulk Fill (TECBF) and SonicFill (SF) were studied. Using MARC-RC, the irradiance delivered to the top surface of the samples 2, 3, 4 and 5 mm thick (n= 5 for each thickness) was adjusted to 800 mW/cm2 for 20 seconds (16 J/cm2) using either a single-wave, Bluephase or a dual-wave, Bluephase G2 LCUs. Light energy transmission through to the bottom surface of the specimens was measured at real time using MARC-RC. The Vickers hardness (VH) was determined using Vickers micro hardness tester and the VHratio was calculated. Data were analyzed using a general linear model in Minitab 16; α= 0.05. TECBF was more translucent than SF (Pwave Bluephase G2). SF showed significantly higher VH ratio than TECBF at all different thickness levels (P 0.05). TECBF showed significantly greater VH ratio when cured with the single-wave Bluephase than when using the dual-wave Bluephase G2 (Penergy through to the bottom surface and the VHratio are material dependent. Although TECBF is more translucent than SF, it showed lower VHratio compared to SF when cured with dual-wave Bluephase G2.

  11. Ultrasonically determined fill pressure and density in closed spherical shells

    International Nuclear Information System (INIS)

    Asaki, T.J.

    1998-01-01

    Experiments have been conducted in which the D 2 fill pressure has been determined for several closed millimeter-size aluminum and beryllium shells. The vibrational resonance frequency spectrum of the shells was used to calculate the sound velocity of the interior gas. This velocity, along with the equation-of-state, determined the gas pressure and density. The accuracy in determining the fill conditions is within 0.5% in both pressure and density for near critical density (ρ approx-gt 9 mol/L) gas over a wide range of temperatures (190 K to 300 K). Reduced accuracy was apparent at low density. An attempt was made to determine the fill density of one shell by acoustic observation of the dew point temperature. While this temperature was recorded very accurately, the uncertainty in the saturated vapor density curve near the critical point yielded inaccurate results. These methods were shown to be unaffected by small deviations in the sphericity of the gas-filled cavity

  12. An energy resolved electron-ion coincidence study near the S 2p thresholds of the SF6 molecule

    International Nuclear Information System (INIS)

    Kivimaeki, A; Ruiz, J Alvarez; Erman, P; Hatherly, P; Garcia, E Melero; Rachlew, E; Rius i Riu, J; Stankiewicz, M

    2003-01-01

    The fragmentation dynamics of the SF 6 molecule following the excitations of S 2p electrons into unoccupied molecular orbitals has been studied using the energy-resolved electron-ion coincidence technique. Fragmentation patterns were found to depend on the particular excitation and on the electronic state of the molecular ion. The spectator resonant Auger decay at the 2p → 6a 1g resonance induces changes in the ion distributions as compared to direct photoionization. Furthermore, coincidence spectra related to the same Auger structure display different ion abundances at the 2t 2g and 4e g shape resonances. Differences were also found in the Auger decay spectra. These findings give further support for the previously suggested many-electron character of the 4e g shape resonance

  13. R & D of a Gas-Filled RF Beam Profile Monitor for Intense Neutrino Beam Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Yonehara, K. [Fermilab; Backfish, M. [Fermilab; Moretti, A. [Fermilab; Tollestrup, A. V. [Fermilab; Watts, A. [Fermilab; Zwaska, R. M. [Fermilab; Abrams, R. [MUONS Inc., Batavia; Cummings, M. A.; Dudas, A. [MUONS Inc., Batavia; Johnson, R. P. [MUONS Inc., Batavia; Kazakevich, G. [MUONS Inc., Batavia; Neubauer, M. [MUONS Inc., Batavia; Liu, Q. [Case Western Reserve U.

    2017-05-01

    We report the R&D of a novel radiation-robust hadron beam profile monitor based on a gas-filled RF cavity for intense neutrino beam experiments. An equivalent RF circuit model was made and simulated to optimize the RF parameter in a wide beam intensity range. As a result, the maximum acceptable beam intensity in the monitor is significantly increased by using a low-quality factor RF cavity. The plan for the demonstration test is set up to prepare for future neutrino beam experiments.

  14. A COMPREHENSIVE STUDY ON APOPTOSIS INDUCTION BY AZADIRACHTIN IN Spodoptera frugiperda CULTURED CELL LINE Sf9.

    Science.gov (United States)

    Shu, Benshui; Wang, Wenxiang; Hu, Qingbo; Huang, Jingfei; Hu, Meiying; Zhong, Guohua

    2015-07-01

    The induction of apoptosis by azadirachtin, a well-known botanical tetranortriterpenoid isolated from the neem tree (Azadirachta indica A. Juss) and other members of the Meliaceae, was investigated in Spodoptera frugiperda cultured cell line (Sf9). Morphological changes in Sf9 cells treated by various concentrations of azadirachtin were observed at different times under light microscopy. Morphological and biochemical analysis indicated that Sf9 cells treated by 1.5 μg/mL azadirachtin showed typical morphological changes, which were indicative of apoptosis and a clear DNA ladder. The flow cytometry analysis showed the apoptosis rate reached a maximum value of 32.66% at 24 h with 1.5 μg/mL azadirachtin in Sf9 cells. The inhibition of Sf9 cell proliferation suggested that the effect of azadirachtin was dose dependent and the EC50 at 48 and 72 h was 2.727 × 10(-6) and 6.348 × 10(-9) μg/mL, respectively. The treatment of azadirachtin in Sf9 cells could significantly increase the activity of Sf caspase-1, but showed no effect on the activity of Topo I, suggesting that the apoptosis induced by azadirachtinin Sf9 cells is through caspase-dependent pathway. These results provided not only a series of morphological, biochemical, and toxicological comprehensive evidences for induction of apoptosis by azadirachtin, but also a reference model for screening insect cell apoptosis inducers from natural compounds. © 2015 Wiley Periodicals, Inc.

  15. Dependence of charge collection distributions and dose on the gas type filling the ionization chamber for a p(66)Be(49) clinical neutron beam

    International Nuclear Information System (INIS)

    Awschalom, M.; Haken, R.K.T.

    1985-01-01

    Measurements of central axis depth charge distributions (CADCD) in a p(66)Be(49) clinical neutron beam using A-150 TE plastic ionization chambers (IC) have shown that these distributions are dependent on the gas type filling the ICs. IC volumes from 0.1 to 8 cm 3 and nine different gases were investigated. Off axis ratios and build-up measurements do not seem to be as sensitive to gas type. The gas dosimetry constants given in the AAPM Protocol for Neutron Beam Dosimetry for air and methane based TE gases were tested for consistency in water and in TE solution filled phantoms at depths of 10 cm, when used in conjunction with an IC having 5 mm thick walls of A-150. 29 refs., 7 figs., 1 tab

  16. Methods and techniques for obtaining significant discharge measurements on high-voltage bushings

    Energy Technology Data Exchange (ETDEWEB)

    Jolley, H E.W.

    1965-05-01

    Forms of discharge tests are described and compared. The use of the Arman and Starr discharge bridge with cathode-ray-tube display is shown to be practicable for bushing testing up to 600 kV. Spurious discharge effects and the precautions necessary to eliminate them are discussed. Consideration is given to calibration methods and to the errors to be expected with various practical circuits. The problem of establishing safe discharge limits for bushings is considered on the basis of a large number of test results and on service experience.

  17. Prosperity against ecology? The environment in the America of G.W. Bush

    International Nuclear Information System (INIS)

    Delbard, O.

    2006-03-01

    The author analysis replaces the Bush administration positions in their socio-cultural context and shows the two faces of the USA, the choice of the prosperity facing the ecology and in parallel a country of many free spaces with powerful groups for the environment preservation. After a presentation of the Bush policy in favor of the prosperity facing the environment, he shows the initiatives of movements in favor of the ecology and the environment, and concludes on the today mutations of the public opinion and some enterprises in theses domains. (A.L.B.)

  18. Boumediene v. Bush: Guantanamo Detainees' Right to Habeas Corpus

    National Research Council Canada - National Science Library

    Garcia, Michael J

    2008-01-01

    In the consolidated cases of Boumediene v. Bush and Al Odah v. United States, decided June 12, 2008, the Supreme Court held in a 5-4 opinion that aliens designated as enemy combatants and detained at the U.S...

  19. Molecular insights of Gas6/TAM in cancer development and therapy.

    Science.gov (United States)

    Wu, Guiling; Ma, Zhiqiang; Hu, Wei; Wang, Dongjin; Gong, Bing; Fan, Chongxi; Jiang, Shuai; Li, Tian; Gao, Jianyuan; Yang, Yang

    2017-03-23

    Since growth arrest-specific gene 6 (Gas6) was discovered in 1988, numerous studies have highlighted the role of the Gas6 protein and its receptors Tyro3, Axl and Mer (collectively referred to as TAM), in proliferation, apoptosis, efferocytosis, leukocyte migration, sequestration and platelet aggregation. Gas6 has a critical role in the development of multiple types of cancers, including pancreatic, prostate, oral, ovarian and renal cancers. Acute myelocytic leukaemia (AML) is a Gas6-dependent cancer, and Gas6 expression predicts poor prognosis in AML. Interestingly, Gas6 also has a role in establishing tumour dormancy in the bone marrow microenvironment and in suppressing intestinal tumorigenesis. Numerous studies regarding cancer therapy have targeted Gas6 and TAM receptors with good results. However, some findings have suggested that Gas6 is associated with the development of resistance to cancer therapies. Concerning these significant effects of Gas6 in numerous cancers, we discuss the roles of Gas6 in cancer development in this review. First, we introduce basic knowledge on Gas6 and TAM receptors. Next, we describe and discuss the involvement of Gas6 and TAM receptors in cancers from different organ systems. Finally, we highlight the progress in therapies targeting Gas6 and TAM receptors. This review presents the significant roles of Gas6 in cancers from different systems and may contribute to the continued promotion of Gas6 as a therapeutic target.

  20. Bush animal attacks: management of complex injuries in a resource-limited setting

    Directory of Open Access Journals (Sweden)

    Mitchell Katrina B

    2011-12-01

    Full Text Available Abstract Introduction Though animal-related injuries and fatalities have been documented throughout the world, the variety of attacks by wild animals native to rural East Africa are less commonly described. Given the proximity of our northwestern Tanzania hospital to Lake Victoria, Lake Tanganyika, and the Serengeti National Park, and presentation of several patients attacked by bush animals and suffering a variety of complex injuries, we sought to report the pattern of attacks and surgical management in a resource-limited setting. Materials and methods Four patients who were admitted to the northwestern Tanzania tertiary referral hospital, Bugando Medical Centre (BMC, in 2010-2011 suffered attacks by different bush animals: hyena, elephant, crocodile, and vervet monkey. These patients were triaged as trauma patients in the Casualty Ward, then admitted for inpatient monitoring and treatment. Their outcomes were followed to discharge. Results The age and gender of the patients attacked was variable, though all but the pediatric patient were participating in food gathering or guarding activities in rural locations at the time of the attacks. All patients required surgical management of their injuries, which included debridement and closure of wounds, chest tube insertion, amputation, and external fixation of an extremity fracture. All patients survived and were discharged home. Discussion Though human injuries secondary to encounters with undomesticated animals such as cows, moose, and camel are reported, they often are indirect traumas resulting from road traffic collisions. Snake attacks are well documented and common. However, this series of unique bush animal attacks describes the initial and surgical management of human injuries in the resource-limited setting of the developing world. Conclusion Animal attacks are common throughout the world, but their pattern may vary in Africa throughout jungle and bush environmental settings. It is

  1. Allergenic sesquiterpene lactones from cushion bush (Leucophyta brownii Cass.)

    DEFF Research Database (Denmark)

    Paulsen, Evy; Gade Hyldgaard, Mette; Andersen, Klaus E.

    2017-01-01

    BACKGROUND: The Australian cushion bush (Leucophyta brownii) of the Compositae family of plants has become a popular pot and container plant. The plant produces the sesquiterpene lactone allergen calocephalin. OBJECTIVES: To assess the sensitizing potential of sesquiterpene lactones from cushion ...

  2. The fluid-filling system for the Borexino solar neutrino detector

    Science.gov (United States)

    Benziger, J.; Cadonati, L.; Calaprice, F.; Chen, M.; Corsi, A.; Dalnoki-Veress, F.; Fernholz, R.; Ford, R.; Galbiati, C.; Goretti, A.; Harding, E.; Ianni, Aldo; Ianni, Andrea; Kidner, S.; Leung, M.; Loeser, F.; McCarty, K.; McKinsey, D.; Nelson, A.; Pocar, A.; Salvo, C.; Schimizzi, D.; Shutt, T.; Sonnenschein, A.

    2009-09-01

    The system for controlled filling of the nested flexible scintillator containment vessels in the Borexino solar neutrino detector is described. The design and operation principles of pressure and shape monitoring systems are presented for gas filling, gas displacement by water, and water displacement by scintillator. System specifications for safety against overstressing the flexible nylon vessels are defined as well as leak-tightness and cleanliness requirements. The fluid-filling system was a major engineering challenge for the Borexino detector.

  3. The role of the gas/plasma plume and self-focusing in a gas-filled capillary discharge waveguide for high-power laser-plasma applications

    CERN Document Server

    Ciocarlan, C.; Islam, M. R.; Ersfeld, B.; Abuazoum, S.; Wilson, R.; Aniculaesei, C.; Welsh, G. H.; Vieux, G.; Jaroszynski, D. A.; 10.1063/1.4822333

    2013-01-01

    The role of the gas/plasma plume at the entrance of a gas-filled capillary discharge plasma waveguide in increasing the laser intensity has been investigated. Distinction is made between neutral gas and hot plasma plumes that, respectively, develop before and after discharge breakdown. Time-averaged measurements show that the on-axis plasma density of a fully expanded plasma plume over this region is similar to that inside the waveguide. Above the critical power, relativistic and ponderomotive selffocusing lead to an increase in the intensity, which can be nearly a factor of 2 compared with the case without a plume. When used as a laser plasma wakefield accelerator, the enhancement of intensity can lead to prompt electron injection very close to the entrance of the waveguide. Self-focusing occurs within two Rayleigh lengths of the waveguide entrance plane in the region, where the laser beam is converging. Analytical theory and numerical simulations show that, for a density of 3.01018 cm3, the peak normalized...

  4. Targeting Gas6/TAM in cancer cells and tumor microenvironment.

    Science.gov (United States)

    Wu, Guiling; Ma, Zhiqiang; Cheng, Yicheng; Hu, Wei; Deng, Chao; Jiang, Shuai; Li, Tian; Chen, Fulin; Yang, Yang

    2018-01-31

    Growth arrest-specific 6, also known as Gas6, is a human gene encoding the Gas6 protein, which was originally found to be upregulated in growth-arrested fibroblasts. Gas6 is a member of the vitamin K-dependent family of proteins expressed in many human tissues and regulates several biological processes in cells, including proliferation, survival and migration, by binding to its receptors Tyro3, Axl and Mer (TAM). In recent years, the roles of Gas6/TAM signalling in cancer cells and the tumour microenvironment have been studied, and some progress has made in targeted therapy, providing new potential directions for future investigations of cancer treatment. In this review, we introduce the Gas6 and TAM receptors and describe their involvement in different cancers and discuss the roles of Gas6 in cancer cells, the tumour microenvironment and metastasis. Finally, we introduce recent studies on Gas6/TAM targeting in cancer therapy, which will assist in the experimental design of future analyses and increase the potential use of Gas6 as a therapeutic target for cancer.

  5. Simultaneous density-field visualization and PIV of a shock-accelerated gas curtain

    Energy Technology Data Exchange (ETDEWEB)

    Prestridge, K.; Rightley, P.M.; Vorobieff, P. [Los Alamos Nat. Lab., NM (United States). Dynamic Exp. Div.; Benjamin, R.F.; Kurnit, N.A.

    2000-10-01

    We describe a highly-detailed experimental characterization of the Richtmyer-Meshkov instability (the impulsively driven Rayleigh-Taylor instability) (Meshkov 1969; Richtmyer 1960). In our experiment, a vertical curtain of heavy gas (SF{sub 6}) flows into the test section of an air-filled, horizontal shock tube. The instability evolves after a Mach 1.2 shock passes through the curtain. For visualization, we pre-mix the SF{sub 6} with a small ({proportional_to}10{sup -5}) volume fraction of sub-micron-sized glycol/water droplets. A horizontal section of the flow is illuminated by a light sheet produced by a combination of a customized, burst-mode Nd:YAG laser and a commercial pulsed laser. Three CCD cameras are employed in visualization. The ''dynamic imaging camera'' images the entire test section, but does not detect the individual droplets. It produces a sequence of instantaneous images of local droplet concentration, which in the post-shock flow is proportional to density. The gas curtain is convected out of the test section about 1 ms after the shock passes through the curtain. A second camera images the initial conditions with high resolution, since the initial conditions vary from test to test. The third camera, ''PIV camera,'' has a spatial resolution sufficient to detect the individual droplets in the light sheet. Images from this camera are interrogated using particle image velocimetry (PIV) to recover instantaneous snapshots of the velocity field in a small (19 x 14 mm) field of view. The fidelity of the flow-seeding technique for density-field acquisition and the reliability of the PIV technique are both quantified in this paper. In combination with wide-field density data, PIV measurements give us additional physical insight into the evolution of the Richtmyer-Meshkov instability in a problem which serves as an excellent test case for general transition-to-turbulence studies. (orig.)

  6. Fabrication of SiC nanopillars by inductively coupled SF6/O2 plasma etching

    International Nuclear Information System (INIS)

    Choi, J H; Bano, E; Latu-Romain, L; Dhalluin, F; Chevolleau, T; Baron, T

    2012-01-01

    In this paper, we demonstrate a top-down fabrication technique for nanometre scale silicon carbide (SiC) pillars using inductively coupled plasma etching. A set of experiments in SF 6 -based plasma was carried out in order to realize high aspect ratio SiC nanopillars. The etched SiC nanopillars using a small circular mask pattern (115 nm diameter) show high aspect ratio (7.4) with a height of 2.2 µm at an optimum bias voltage (300 V) and pressure (6 mTorr). Under the optimal etching conditions using a large circular mask pattern with 370 nm diameter, the obtained SiC nanopillars exhibit high anisotropy features (6.4) with a large etch depth (>7 µm). The etch characteristic of the SiC nanopillars under these conditions shows a high etch rate (550 nm min -1 ) and a high selectivity (over 60 for Ni). We also studied the etch profile of the SiC nanopillars and mask evolution over the etching time. As the mask pattern size shrinks in nanoscale, vertical and lateral mask erosion plays a crucial role in the etch profile of the SiC nanopillars. Long etching process makes the pillars appear with a hexagonal shape, coming from the crystallographic structure of α-SiC. It is found that the feature of pillars depends not only on the etching process parameters, but also on the crystallographic structure of the SiC phase. (paper)

  7. Development of Bushing Compounds for Tracked Vehicles

    Science.gov (United States)

    1990-10-01

    unwanted stepchild - part of called anti patented NBR -12 formulation the family (system), but devoid of needed indicated that service life could be...as Development and Engineering Center’s long. Bushings currently used in the M I track Rubber and Coated Fabrics Research Group assembly typically fail...formulations of should be improved. Numerous selected candidate natural rubber , propylene formulations-based on natural rubber , oxide, and silicone

  8. Americium/curium bushing melter drain tests

    International Nuclear Information System (INIS)

    Smith, M.E.; Hardy, B.J.; Smith, M.E.

    1997-01-01

    Americium and curium were produced in the past at the Savannah River Site (SRS) for research, medical, and radiological applications. They have been stored in a nitric acid solution in an SRS reprocessing facility for a number of years. Vitrification of the americium/curium (Am/Cm) solution will allow the material to be safely stored or transported to the DOE Oak Ridge Reservation. Oak Ridge is responsible for marketing radionuclides for research and medical applications. The bushing melter technology being used in the Am/Cm vitrification research work is also under consideration for the stabilization of other actinides such as neptunium and plutonium. A series of melter drain tests were conducted at the Savannah River Technology Center to determine the relationship between the drain tube assembly operating variables and the resulting pour initiation times, glass flowrates, drain tube temperatures, and stop pour times. Performance criteria such as ability to start and stop pours in a controlled manner were also evaluated. The tests were also intended to provide support of oil modeling of drain tube performance predictions and thermal modeling of the drain tube and drain tube heater assembly. These drain tests were instrumental in the design of subsequent melter drain tube and drain tube heaters for the Am/Cm bushing melter, and therefore in the success of the Am/Cm vitrification and plutonium immobilization programs

  9. Estimating greenhouse gas fluxes from constructed wetlands used for water quality improvement

    Directory of Open Access Journals (Sweden)

    Sukanda Chuersuwan

    2014-06-01

    Full Text Available Methane (CH4 , nitrous oxide (N2O and carbon dioxide (CO2 fluxes were evaluated from constructed wetlands (CWs used to improve domestic wastewater quality. Experiments employed subsurface flow (SF and free water surface flow (FWS CWs planted with Cyperus spp. Results showed seasonal fluctuations of greenhouse gas fluxes. Greenhouse gas fluxes from SF-CWs and FWS-CWS were significantly different (p<0.05 while pollutant removal efficiencies of both CWs were not significantly different. The average CH4 , N2O and CO2 fluxes from SF-CWs were 2.9±3.5, 1.0±1.7, and 15.2±12.3 mg/m2 /hr, respectively, corresponding to the average global warming potential (GWP of 392 mg CO2 equivalents/m2 /hr. For FWS-CWs, the average CH4 , N2O and CO2 fluxes were 5.9±4.8, 1.8±1.0, and 29.6±20.2 mg/m2 /hr, respectively, having an average GWP of 698 mg CO2 equivalents/m2 /hr. Thus, FWS-CWs have a higher GWP than SF-CWs when they were used as a system for domestic water improvement.

  10. Gas-filled Rugby hohlraum energetics and implosions experiments on OMEGA

    Science.gov (United States)

    Casner, Alexis; Philippe, F.; Tassin, V.; Seytor, P.; Monteil, M. C.; Villette, B.; Reverdin, C.

    2010-11-01

    Recent experiments [1,2] have validated the x-ray drive enhancement provided by rugby-shaped hohlraums over cylinders in the indirect drive (ID) approach to inertial confinement fusion (ICF). This class of hohlraum is the baseline design for the Laser Mégajoule program, is also applicable to the National Ignition Facility and could therefore benefit ID Inertial Fusion Energy studies. We have carried out a serie of energetics and implosions experiments with OMEGA ``scale 1'' rugby hohlraums [1,2]. For empty hohlraums these experiments provide complementary measurements of backscattered light along 42 cone, as well as detailed drive history. In the case of gas-filled rugby hohlraums we have also study implosion performance (symmetry, yield, bangtime, hotspot spectra...) using a high contrast shaped pulse leading to a different implosion regime and for a range of capsule convergence ratios. These results will be compared with FCI2 hydrocodes calculations and future experimental campaigns will be suggested. [4pt] [1] F. Philippe et al., Phys. Rev. Lett. 104, 035004 (2010). [0pt] [2] H. Robey et al., Phys. Plasnas 17, 056313 (2010).

  11. Convergent ablation measurements with gas-filled rugby hohlraum on OMEGA

    International Nuclear Information System (INIS)

    Casner, A.; Jalinaud, T.; Galmiche, D.

    2016-01-01

    Convergent ablation experiments with gas-filled rugby hohlraum were performed for the first time on the OMEGA laser facility. A time resolved 1D streaked radiography of capsule implosion is acquired in the direction perpendicular to hohlraum axis, whereas a 2D gated radiography is acquired at the same time along the hohlraum axis on a x-ray framing camera. The implosion trajectory has been measured for various kinds of uniformly doped ablators, including germanium-doped and silicon-doped polymers (CH), at two different doping fraction (2% and 4% at.). Our experiments aimed also at measuring the implosion performance of laminated capsules. A laminated ablator is constituted by thin alternate layers of un-doped and doped CH. It has been previously shown in planar geometry that laminated ablators could mitigate Rayleigh Taylor growth at ablation front. Our results confirm that the implosion of a capsule constituted with a uniform or laminated ablator behaves similarly, in accordance with post-shot simulations performed with the CEA hydrocode FCI2. (paper)

  12. BUDDLEJA DAVIDII (BUTTERFLY BUSH): A GROWING THREAT TO RIPARIA?

    Science.gov (United States)

    Buddleja davidii, an Asian shrub or small tree (family Buddlejaceae; commonly referred to as Butterfly bush) is found in the United States, New Zealand, Australia, and Europe as a popular ornamental and an aggressive invasive that has become widespread in floodplains, riverbeds, ...

  13. Electro-actuation characteristics of Cl2 and SF6 plasma-treated IPMC actuators

    International Nuclear Information System (INIS)

    Saher, Saim; Kim, Woojin; Moon, Sungwon; Jin Kim, H; Kim, Yong Hyup

    2010-01-01

    This paper describes plasma treatments that improve the actuation properties by modifying the surface morphology of ionic polymer metal composites (IPMC). The proposed Cl 2 and SF 6 plasmas change the surface appearance of the electroactive polymer, and scanning electron microscopy (SEM) of the plasma-treated surfaces reveals the development of round and cone-shaped microstructures. After electroless chemical metal plating, these microstructures significantly alter the characteristics of the IPMC electrode. In plasma-treated IPMCs, the densely packed platinum nanoparticles have produced a relatively thick electrode layer. This configuration has led to the improvement in the electrical properties of the IPMC: surface resistance is noticeably decreased, whereas electrical capacitance is increased. These changes in the electrical properties have considerably enhanced the actuation parameters: displacement, force and operational life are increased by more than three times relative to the conventional IPMC. Our experimental data suggest a relationship between the IPMC actuator's electrical properties and actuation parameters: actuators with lower surface resistance generate large deflection and actuators with higher capacitance generate large actuation force. The actuation tests including coin lifting suggests the potential of the modified IPMC for artificial muscle applications

  14. Response of total phenolic content and antioxidant activities of bush

    African Journals Online (AJOL)

    user

    OF BUSH TEA AND SPECIAL TEA USING DIFFERENT SELECTED. EXTRACTION ... 3,3'digallate and caffeine). Tea leaves have ..... Effects of solvent extraction on phenolic content and ... Critical Reviews in Food Science and Nutrition,.

  15. Intracellular distribution of TM4SF1 and internalization of TM4SF1-antibody complex in vascular endothelial cells

    International Nuclear Information System (INIS)

    Sciuto, Tracey E.; Merley, Anne; Lin, Chi-Iou; Richardson, Douglas; Liu, Yu; Li, Dan; Dvorak, Ann M.; Dvorak, Harold F.; Jaminet, Shou-Ching S.

    2015-01-01

    Transmembrane-4 L-six family member-1 (TM4SF1) is a small plasma membrane-associated glycoprotein that is highly and selectively expressed on the plasma membranes of tumor cells, cultured endothelial cells, and, in vivo, on tumor-associated endothelium. Immunofluorescence microscopy also demonstrated TM4SF1 in cytoplasm and, tentatively, within nuclei. With monoclonal antibody 8G4, and the finer resolution afforded by immuno-nanogold transmission electron microscopy, we now demonstrate TM4SF1 in uncoated cytoplasmic vesicles, nuclear pores and nucleoplasm. Because of its prominent surface location on tumor cells and tumor-associated endothelium, TM4SF1 has potential as a dual therapeutic target using an antibody drug conjugate (ADC) approach. For ADC to be successful, antibodies reacting with cell surface antigens must be internalized for delivery of associated toxins to intracellular targets. We now report that 8G4 is efficiently taken up into cultured endothelial cells by uncoated vesicles in a dynamin-dependent, clathrin-independent manner. It is then transported along microtubules through the cytoplasm and passes through nuclear pores into the nucleus. These findings validate TM4SF1 as an attractive candidate for cancer therapy with antibody-bound toxins that have the capacity to react with either cytoplasmic or nuclear targets in tumor cells or tumor-associated vascular endothelium. - Highlights: • Anti-TM4SF1 antibody 8G4 was efficiently taken up by cultured endothelial cells. • TM4SF1–8G4 internalization is dynamin-dependent but clathrin-independent. • TM4SF1–8G4 complexes internalize along microtubules to reach the perinuclear region. • Internalized TM4SF1–8G4 complexes pass through nuclear pores into the nucleus. • TM4SF1 is an attractive candidate for ADC cancer therapy

  16. Intracellular distribution of TM4SF1 and internalization of TM4SF1-antibody complex in vascular endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Sciuto, Tracey E.; Merley, Anne; Lin, Chi-Iou [Center for Vascular Biology Research and Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School (United States); Richardson, Douglas [Department of Molecular and Cellular Biology, Harvard University (United States); Liu, Yu [Department of Pharmacology, Shanxi Medical University, Xinjiannanlu 56, Shanxi Province, Taiyuan 030001 (China); Li, Dan; Dvorak, Ann M. [Center for Vascular Biology Research and Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School (United States); Dvorak, Harold F., E-mail: hdvorak@bidmc.harvard.edu [Center for Vascular Biology Research and Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School (United States); Jaminet, Shou-Ching S., E-mail: sjaminet@bidmc.harvard.edu [Center for Vascular Biology Research and Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School (United States)

    2015-09-25

    Transmembrane-4 L-six family member-1 (TM4SF1) is a small plasma membrane-associated glycoprotein that is highly and selectively expressed on the plasma membranes of tumor cells, cultured endothelial cells, and, in vivo, on tumor-associated endothelium. Immunofluorescence microscopy also demonstrated TM4SF1 in cytoplasm and, tentatively, within nuclei. With monoclonal antibody 8G4, and the finer resolution afforded by immuno-nanogold transmission electron microscopy, we now demonstrate TM4SF1 in uncoated cytoplasmic vesicles, nuclear pores and nucleoplasm. Because of its prominent surface location on tumor cells and tumor-associated endothelium, TM4SF1 has potential as a dual therapeutic target using an antibody drug conjugate (ADC) approach. For ADC to be successful, antibodies reacting with cell surface antigens must be internalized for delivery of associated toxins to intracellular targets. We now report that 8G4 is efficiently taken up into cultured endothelial cells by uncoated vesicles in a dynamin-dependent, clathrin-independent manner. It is then transported along microtubules through the cytoplasm and passes through nuclear pores into the nucleus. These findings validate TM4SF1 as an attractive candidate for cancer therapy with antibody-bound toxins that have the capacity to react with either cytoplasmic or nuclear targets in tumor cells or tumor-associated vascular endothelium. - Highlights: • Anti-TM4SF1 antibody 8G4 was efficiently taken up by cultured endothelial cells. • TM4SF1–8G4 internalization is dynamin-dependent but clathrin-independent. • TM4SF1–8G4 complexes internalize along microtubules to reach the perinuclear region. • Internalized TM4SF1–8G4 complexes pass through nuclear pores into the nucleus. • TM4SF1 is an attractive candidate for ADC cancer therapy.

  17. Breakdown characteristics of electro-negative gases under needle-plane gap. Hari-hiraita gap ni okeru denkiteki fusei gas no zetsuen hakai tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, H.; Onoda, M.; Amakawa, K. (Himeji Institute of Technology, Hyogo (Japan)); Kuroda, S. (Nitto Denko Corp., Tokyo (Japan))

    1990-07-20

    The voltage-time (V-t) characteristics of corona onset and breakdown were examined in electro-negative gases as SF {sub 6} and CCl {sub 2} F {sub 2}, using a needle-plane electrode with small gap and {mu} s square pulse voltage with various wave fronts. The V-t characteristics in electro-neutral gas as N {sub 2} ordinarily descended rightwards, but those in SF {sub 6} descended rightwards only in smaller gaps and lower gas pressures. In the pulse voltage with shorter wave fronts, those in SF {sub 6} also offered a particular shape descending leftwards. The particular shape was dependent on the steepness of the pulse wave front, being strongly affected by shorter wave fronts, and also strongly related to the onset and development length of corona. The particular phenomenon of V-t characteristics was observed more obviously at a positive needle than negative one without any extremely long corona lengths at negative one, indicating a polarity effect. The phenomenon was also observed in CCl {sub 2} F {sub 2} as particular one in electro-negative gases. 21 refs., 12 figs.

  18. The Second Administration of George W. Bush and U.S.-Russia Relations

    Directory of Open Access Journals (Sweden)

    Rybalko Olga

    2014-12-01

    Full Text Available This article is devoted to the analysis of changes in the U.S.-Russia relationships during the presidency of George W. Bush and to the detection of the origins of these changes. The attention is paid to conceptual foreign policy views of the most influential members of administration. The renewal of staff in U.S. administration was one of the important factors of toughening the Russian course of the American foreign policy. At the beginning of the second presidency of George Bush the ratio of forces in the American Congress changed. Opposition forces received the majority in the Congress. This circumstance became the other reason of change of the U.S.-Russia relationships. The bilateral relations during the specified period were complicated by aspiration of the USA to strengthen the influence on the territories of the Post-Soviet states. It caused discontent of Moscow. At the same time, some aspects of the Russian-Iranian nuclear cooperation caused criticism of Washington. The role of personal diplomacy is noted as a factor of forming bilateral relations. During the second term of the presidency of George W. Bush this factor didn't lose its value in comparison with the first term. The article gives the assessment of work of the Bush’s second administration at the Russian direction. The author notes the American focus on the strategy of “selective partnership” with Russia. The conclusion is drawn on George Bush's aspiration to preservation of balance in the U.S.-Russia relations under the conditions of increasing strains.

  19. 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

  20. Bush encroachment monitoring using multi-temporal Landsat data and random forests

    Science.gov (United States)

    Symeonakis, E.; Higginbottom, T.

    2014-11-01

    It is widely accepted that land degradation and desertification (LDD) are serious global threats to humans and the environment. Around a third of savannahs in Africa are affected by LDD processes that may lead to substantial declines in ecosystem functioning and services. Indirectly, LDD can be monitored using relevant indicators. The encroachment of woody plants into grasslands, and the subsequent conversion of savannahs and open woodlands into shrublands, has attracted a lot of attention over the last decades and has been identified as a potential indicator of LDD. Mapping bush encroachment over large areas can only effectively be done using Earth Observation (EO) data and techniques. However, the accurate assessment of large-scale savannah degradation through bush encroachment with satellite imagery remains a formidable task due to the fact that on the satellite data vegetation variability in response to highly variable rainfall patterns might obscure the underlying degradation processes. Here, we present a methodological framework for the monitoring of bush encroachment-related land degradation in a savannah environment in the Northwest Province of South Africa. We utilise multi-temporal Landsat TM and ETM+ (SLC-on) data from 1989 until 2009, mostly from the dry-season, and ancillary data in a GIS environment. We then use the machine learning classification approach of random forests to identify the extent of encroachment over the 20-year period. The results show that in the area of study, bush encroachment is as alarming as permanent vegetation loss. The classification of the year 2009 is validated yielding low commission and omission errors and high k-statistic values for the grasses and woody vegetation classes. Our approach is a step towards a rigorous and effective savannah degradation assessment.

  1. filled neutron detectors

    Indian Academy of Sciences (India)

    Boron trifluoride (BF3) proportional counters are used as detectors for thermal neutrons. They are characterized by high neutron sensitivity and good gamma discriminating properties. Most practical BF3 counters are filled with pure boron trifluoride gas enriched up to 96% 10B. But BF3 is not an ideal proportional counter ...

  2. Baltic leaders jockey with Bush to get their message across

    Index Scriptorium Estoniae

    2005-01-01

    USA president George Bush lubas pärast kõnelemist Mart Laari ning Vaira Vike-Freibergaga arutada kohtumisel president Vladimir Putiniga suhteid Venemaa ja Balti riikide vahel. Lisa: Vladimir Putini arvamus Molotovi-Ribbentropi pakti kohta

  3. Heavy ion beam propagation through a gas-filled chamber for inertial confinement fusion

    International Nuclear Information System (INIS)

    Barboza, N.O.

    1996-10-01

    The work presented here evaluates the dynamics of a beam of heavy ions propagating through a chamber filled with gas. The motivation for this research stems from the possibility of using heavy ion beams as a driver in inertial confinement fusion reactors for the purpose of generating electricity. Such a study is important in determining the constraints on the beam which limit its focus to the small radius necessary for the ignition of thermonuclear microexplosions which are the source of fusion energy. Nuclear fusion is the process of combining light nuclei to form heavier ones. One possible fusion reaction combines two isotopes of hydrogen, deuterium and tritium, to form an alpha particle and a neutron, with an accompanying release of ∼17.6 MeV of energy. Generating electricity from fusion requires that we create such reactions in an efficient and controlled fashion, and harness the resulting energy. In the inertial confinement fusion (ICF) approach to energy production, a small spherical target, a few millimeters in radius, of deuterium and tritium fuel is compressed so that the density and temperature of the fuel are high enough, ∼200 g/cm 3 and ∼20 keV, that a substantial number of fusion reactions occur; the pellet microexplosion typically releases ∼350 MJ of energy in optimized power plant scenarios

  4. Applicability of fiber model in seismic response analysis for center-clamp type bushings on transformers

    International Nuclear Information System (INIS)

    Miyagawa, Yoshinori; Sato, Hiroaki

    2015-01-01

    A bushing is a device for insulation and support of a conductor. Especially it is called center-clamp type when it is connected with a metal holder through clamping force. As a consequence of damage of center-clamp type bushings in Tohoku Earthquake in 2011, refinement of the response analysis method and review of the seismic design procedure became necessary. In the present report, the fiber model, which can evaluate non-linear behavior in the section subjected to axial force and bending moment, was implemented to the CRIEPI's finite element analysis program 'Mastrd' considering following characteristics of center-clamp type bushings. a) The gasket section between a porcelain tube and a metal holder has a torus shape. b) Springs around the top of the bushing give clamping force, but they lock in excessive base rotation. c) The gasket does not resist against tension. d) Local resistance against compression due to bending increases in use of very thin gaskets. The developed program was verified through comparison with the shaking table test result for real bushings whose voltage classes were 154 kV and 275 kV. Deformation indices as rotation angle and base opening due to bending were influenced by damping conditions. Though there was not the condition which brought about remarkable underestimation, reduction of damping for a fiber model element was preferable for safety. On the other hand, bending moment was consistent with experimental results because it tended not to fluctuate in the non-linear region. (author)

  5. FABRICATION OF GAS-FILLED TUNGSTEN-COATED GLASS SHELLS

    International Nuclear Information System (INIS)

    NIKROO, A; BAUGH, W; STEINMAN, D.A.

    2003-09-01

    OAK-B135 Deuterium (D 2 ) filled glass shells coated with a high Z element are needed for high energy density (HED) experiments by researchers at Los Alamos National Laboratory. They report here on our initial attempt to produce such shells. Glass shells made using the drop tower technique were coated with gold, palladium or tungsten, or a mixture of two of these elements. It was found that gold and palladium coatings did not stick well to the glass and resulted in poor or delaminated films. Tungsten coatings resulted in films suitable for these targets. Bouncing of shells during coating resulted in uniform tungsten coatings, but the surface of such coatings were filled with small nodules. Proper agitation of shells using a tapping technique resulted in smooth films with minimal particulate contamination. For coating rates of ∼ 0.15 (micro)m/hr coatings with ∼ 2 nm RMS surface finish could be deposited. The surface roughness of coatings at higher rates, 0.7 (micro)m/hr, was considerably worse (∼ 100 nm RMS). The columnar structure of the coatings allowed permeation filling of the tungsten coated glass shells with deuterium at 300 C

  6. Convergent ablation measurements of plastic ablators in gas-filled rugby hohlraums on OMEGA

    Science.gov (United States)

    Casner, A.; Jalinaud, T.; Masse, L.; Galmiche, D.

    2015-10-01

    Indirect-drive implosions experiments were conducted on the Omega Laser Facility to test the performance of uniformly doped plastic ablators for Inertial Confinement Fusion. The first convergent ablation measurements in gas-filled rugby hohlraums are reported. Ignition relevant limb velocities in the range from 150 to 300 μm .n s-1 have been reached by varying the laser drive energy and the initial capsule aspect ratio. The measured capsule trajectory and implosion velocity are in good agreement with 2D integrated simulations and a zero-dimensional modeling of the implosions. We demonstrate experimentally the scaling law for the maximum implosion velocity predicted by the improved rocket model [Y. Saillard, Nucl. Fusion 46, 1017 (2006)] in the high-ablation regime case.

  7. Bushes of vibrational modes for Fermi-Pasta-Ulam chains

    Science.gov (United States)

    Chechin, G. M.; Novikova, N. V.; Abramenko, A. A.

    2002-06-01

    Some exact solutions and multimode invariant submanifolds were found for the Fermi-Pasta-Ulam (FPU)- β model by Poggi and Ruffo [Physica D 103 (1997) 251]. In the present paper we demonstrate how results of such a type can be obtained for an arbitraryN-particle chain with periodic boundary conditions with the aid of our group-theoretical approach [Physica D 117 (1998) 43] based on the concept of bushes of normal modes in mechanical systems with discrete symmetry. The integro-differential equation describing the FPU- α dynamics in the modal space is derived. The loss of stability of the bushes of modes for the FPU- α model, in particular, for the limiting case N→∞ for the dynamical regime with displacement pattern having period twice the lattice spacing ( π-mode) is studied. Our results for the FPU- α chain are compared with those by Poggi and Ruffo for the FPU- β chain.

  8. Oliver Stone : "Bush oli paadialune!" / Oliver Stone ; interv. Margit Tõnson

    Index Scriptorium Estoniae

    Stone, Oliver

    2008-01-01

    Kreekas, Thessaloniki filmifestivalil antud intervjuu. Festivalil linastus režissööri mängufilm "W", mille peaosas George Bush jun. (mängib Josh Brolin). Lisaks filmist : ""W" - ümbersündinud mehe kentsakas portree"

  9. Comparison of intraocular pressure measured by non-contact air puff versus Goldmann applanation tonometers in gas-filled vitrectomized eyes.

    Science.gov (United States)

    Patikulsila, Direk; Taweemankongsab, Srisuda; Ngamtipakorn, Supob

    2003-05-01

    To compare intraocular pressure (IOP) measured by two different instruments, air puff tonometer (APT) versus Goldmann applanation tonometer (GAT), in gas-filled vitrectomized eyes. Three-month, prospective, comparative trial. Thirty-eight patients (38 eyes), who underwent a pars plana vitrectomy (PPV) with gas injection, were enrolled in the study. The IOP was measured by an APT, followed by GAT within 10 minutes by two different, masked investigators. IOPs were measured by two methods and then were compared. Overall, there was a high correlation between both measurements (r = 0.908, p 0.05). By a subgroup analysis of 17 eyes with IOP measured by a GAT of 21 mmHg or less, the APT readings (15.28 +/- 4.81) and GAT readings (14.47 +/- 3.89) were not significantly different (p > 0.05). Of 21 eyes, with IOP measured by a GAT of 22 mmHg or more, the APT readings (26.88 +/- 8.81) were significantly lower than those obtained by the GAT (29.62 +/- 7.69) (p < 0.05). In gas-filled vitrectomized eyes, IOP measurements obtained by an APT correlated well with those obtained by GAT, especially when the IOP was within normal range. However, in eyes with elevated IOP, the APT significantly underestimated the IOP measurement when compared to the gold standard, GAT.

  10. Alternatives to argon for gas stopping volumes in the B194 neutron imager

    Energy Technology Data Exchange (ETDEWEB)

    Bleuel, D. L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Anderson, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Caggiano, J. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hall, J. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Johnson, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ratkiewicz, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Rusnak, B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-05-17

    In a recent experiment at Lawrence Berkeley National Laboratory, the 40Ar(d,p)41Ar excitation function between 3-7 MeV was measured, confirming a previous estimation that there may be an intolerable radiation dose from 41Ar production by slowing to rest 6.74 MeV deuterons in the gas cell of the neutron imaging facility being constructed in B194. Gas alternatives to argon are considered, including helium, nitrogen (N2), neon, sulfur hexafluoride (SF6), krypton, and xenon, as well as high atomic number solid backings such as tantalum.

  11. Assessing the Debt: George W. Bush's Legacy and the Future of Public Education under Barack Obama

    Science.gov (United States)

    Means, Alex; Taylor, Kendall

    2010-01-01

    This article utilizes Gloria Ladson-Billings' notion of educational debt in order to explore the historical, economic, and cultural politics of education reform under George W. Bush and Barack Obama. It tracks the No Child Left Behind Act across a number of fields in order to claim that Bush's expansion of the educational debt should be understood…

  12. 48 CFR 53.232 - Contract financing (SF 1443).

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Contract financing (SF 1443). 53.232 Section 53.232 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION (CONTINUED) CLAUSES AND FORMS FORMS Prescription of Forms 53.232 Contract financing (SF 1443). SF 1443 (JUL...

  13. Age determination in the bush squirrel, Paraxerus cepapi cepapi ...

    African Journals Online (AJOL)

    Tooth eruption and wear, measurements of skulls, eye-lens mass determination and different aspects of phallic morphology were used in an attempt at age classification in the bush squirrel, Paraxerus c. cepapi. The first method proved the most practical and allowed for three immature and three adult age classes.

  14. Integrated PC-based system for detecting and parameter monitoring at the Dubna Gas Filled Recoil Separator

    International Nuclear Information System (INIS)

    Tsyganov, Yu.S.; Polyakov, A.N.; Sukhov, A.M.

    2012-01-01

    New detection system of the Dubna Gas Filled Recoil Separator (DGFRS) was put into operation in May 2012. It includes 32-strip position sensitive PIPS detector manufactured by CANBERRA NV, 24-strip back side PIPS detector, 8-strip V ETO P IPS detector, time-of-flight low pressure (∼1.7 Torr) pentane-filled gaseous detector, CAMAC fast ADC's with 5 μs dead time per three signals (energy, top position, bottom position), modified CC012 crate controller and PC-based C ++ Builder code for spectrometry data acquisition. New parameter monitoring system (project) is reported too together with the brief review of the present system. It is planned to put into operation with this system during 2013-2014. Examples of applications in the long-term experiments aimed at the synthesis of superheavy elements in 48 Ca induced complete fusion nuclear reactions are also presented. Namely with the DGFRS facility 45 new isotopes of superheavy nuclei were synthesized since 2001

  15. A portable gas recirculation unit for gaseous detectors

    Science.gov (United States)

    Guida, R.; Mandelli, B.

    2017-10-01

    The use of greenhouse gases (usually C2H2F4, CF4 and SF6) is sometimes necessary to achieve the required performance for some gaseous detectors. The consumption of these gases in the LHC systems is reduced by recycling the gas mixture thanks to a complex gas recirculation system. Beyond greenhouse gas consumption due to LHC systems, a considerable contribution is generated by setups used for LHC detector upgrade projects, R&D activities, detector quality assurance or longevity tests. In order to minimise this emission, a new flexible and portable gas recirculation unit has been developed. Thanks to its low price, flexibility and user-friendly operation it can be easily adapted for the different types of detector systems and set-ups.

  16. The effect of SF6 addition in a Cl2/Ar inductively coupled plasma for deep titanium etching

    Science.gov (United States)

    Laudrel, E.; Tillocher, T.; Meric, Y.; Lefaucheux, P.; Boutaud, B.; Dussart, R.

    2018-05-01

    Titanium is a material of interest for the biomedical field and more particularly for body implantable devices. Titanium deep etching by plasma was carried out in an inductively coupled plasma with a chlorine-based chemistry for the fabrication of titanium-based microdevices. Bulk titanium etch rate was first studied in Cl2/Ar plasma mixture versus the source power and the self-bias voltage. The plasma was characterized by Langmuir probe and by optical emission spectroscopy. The addition of SF6 in the plasma mixture was investigated. Titanium etch rate was optimized and reached a value of 2.4 µm · min-1. The nickel hard mask selectivity was also enhanced. The etched titanium surface roughness was reduced significantly.

  17. A study of the valence shell photoelectron and photoabsorption spectra of CF3SF5

    International Nuclear Information System (INIS)

    Holland, D M P; Shaw, D A; Walker, I C; McEwen, I J; Apra, E; Guest, M F

    2005-01-01

    The outer valence shell photoelectron spectrum of CF 3 SF 5 has been studied experimentally and theoretically. Synchrotron radiation has been used to record angle-resolved outer valence shell photoelectron spectra of CF 3 SF 5 in the photon energy range 18-60 eV. These spectra have allowed photoelectron asymmetry parameters and branching ratios to be derived. The Outer Valence Green's Function approach has been employed to calculate the molecular orbital configuration and associated binding energies. A charge distribution analysis has also been obtained. Assignments have been proposed for the peaks observed in the photoelectron spectrum. The absolute photoabsorption cross section of CF 3 SF 5 has been measured from threshold to 40 eV, and strongly resembles that of SF 6 . Assignments, involving intravalence transitions, have been proposed for some of the principal features appearing in the photoabsorption spectrum of CF 3 SF 5

  18. SF3B1-initiating mutations in MDS-RSs target lymphomyeloid hematopoietic stem cells.

    Science.gov (United States)

    Mortera-Blanco, Teresa; Dimitriou, Marios; Woll, Petter S; Karimi, Mohsen; Elvarsdottir, Edda; Conte, Simona; Tobiasson, Magnus; Jansson, Monika; Douagi, Iyadh; Moarii, Matahi; Saft, Leonie; Papaemmanuil, Elli; Jacobsen, Sten Eirik W; Hellström-Lindberg, Eva

    2017-08-17

    Mutations in the RNA splicing gene SF3B1 are found in >80% of patients with myelodysplastic syndrome with ring sideroblasts (MDS-RS). We investigated the origin of SF3B1 mutations within the bone marrow hematopoietic stem and progenitor cell compartments in patients with MDS-RS. Screening for recurrently mutated genes in the mononuclear cell fraction revealed mutations in SF3B1 in 39 of 40 cases (97.5%), combined with TET2 and DNMT3A in 11 (28%) and 6 (15%) patients, respectively. All recurrent mutations identified in mononuclear cells could be tracked back to the phenotypically defined hematopoietic stem cell (HSC) compartment in all investigated patients and were also present in downstream myeloid and erythroid progenitor cells. While in agreement with previous studies, little or no evidence for clonal ( SF3B1 mutation) involvement could be found in mature B cells, consistent involvement at the pro-B-cell progenitor stage was established, providing definitive evidence for SF3B1 mutations targeting lymphomyeloid HSCs and compatible with mutated SF3B1 negatively affecting lymphoid development. Assessment of stem cell function in vitro as well as in vivo established that only HSCs and not investigated progenitor populations could propagate the SF3B1 mutated clone. Upon transplantation into immune-deficient mice, SF3B1 mutated MDS-RS HSCs differentiated into characteristic ring sideroblasts, the hallmark of MDS-RS. Our findings provide evidence of a multipotent lymphomyeloid HSC origin of SF3B1 mutations in MDS-RS patients and provide a novel in vivo platform for mechanistically and therapeutically exploring SF3B1 mutated MDS-RS. © 2017 by The American Society of Hematology.

  19. Lifetime and shelf life of sealed tritium-filled plasma focus chambers with gas generator

    Directory of Open Access Journals (Sweden)

    B.D. Lemeshko

    2017-11-01

    Full Text Available The paper describes the operation features of plasma focus chambers using deuterium–tritium mixture. Handling tritium requires the use of sealed, vacuum-tight plasma focus chambers. In these chambers, there is an accumulation of the impurity gases released from the inside surfaces of the electrodes and the insulator while moving plasma current sheath inside chambers interacting with β-electrons generated due to the decay of tritium. Decay of tritium is also accompanied by the accumulation of helium. Impurities lead to a decreased yield of neutron emission from plasma focus chambers, especially for long term operation. The paper presents an option of absorption type gas generator in the chamber based on porous titanium, which allows to significantly increase the lifetime and shelf life of tritium chambers. It also shows the results of experiments on the comparison of the operation of sealed plasma focus chambers with and without the gas generator. Keywords: Plasma focus, Neutron yield, Tritium-filled plasma focus chambers, PACS Codes: 29.25.-v, 52.58.Lq

  20. Production components and yield of bushing snap bean in conventional and organic production systems

    Directory of Open Access Journals (Sweden)

    Guilherme Renato Gomes

    2017-10-01

    Full Text Available Production systems influence crops differently, mainly in terms of yield. However, there are few studies that have evaluated different bushing snap bean genotypes in different systems. Thus, this study aimed to evaluate the production components and yield of bushing snap beans in conventional and organic production systems. The experimental design was a randomized complete block, in a factorial 6 × 2 arrangement, corresponding to six genotypes and two production systems, with three replications. The genotypes Isla Manteiga Baixo®, Isla Macarrão Baixo®, Feltrin Vicenza Amarelo Baixo®, and Feltrin Macarrão Napoli®, UEL 1, and UEL 2 were submitted to the following determinations: days to flowering; plant height; medium number of pods per plant; average pod mass, length, and diameter; and yield of commercial pods. A joint analysis of variance was conducted by applying the F test, with mean comparison performed using the Tukey’s test (p < 0.05. Anthesis of the genotypes Feltrin Vicenza Amarelo Baixo, UEL 2, Isla Macarrão Baixo, and Feltrin Macarrão Napoli is anticipated in the conventional production system. The genotype UEL 2 shows higher precocity in anthesis within the conventional system. The genotypes Isla Manteiga Baixo and UEL 1 produce more pods per plant in the conventional system. In the organic system, the genotype Feltrin Macarrão Napoli produces double the number of pods per plant compared with Isla Manteiga Baixo. The organic system leads to greater plant height and average mass, length, and diameter of pods in relation to the conventional system. The commercial pod yield of bushing snap bean is not altered by differences in the production system or genotype.