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Sample records for gas operational discharges

  1. GAS DISCHARGE DEVICES

    DOEpatents

    Arrol, W.J.; Jefferson, S.

    1957-08-27

    The construction of gas discharge devices where the object is to provide a gas discharge device having a high dark current and stabilized striking voltage is described. The inventors have discovered that the introduction of tritium gas into a discharge device with a subsequent electrical discharge in the device will deposit tritium on the inside of the chamber. The tritium acts to emit beta rays amd is an effective and non-hazardous way of improving the abovementioned discharge tube characteristics

  2. Introduction to gas discharges

    NASA Astrophysics Data System (ADS)

    Braithwaite, N. St J.

    2000-11-01

    This is a tutorial article. An introductory discussion of direct current gas discharges is presented. Beginning with basic ideas from kinetic theory, gas discharge plasmas are described in terms of phenomena observed in the laboratory. Various models are introduced to account for electrical breakdown, plasma boundaries and the longitudinal and transverse structure of discharges.

  3. GAS DISCHARGE DEVICES

    DOEpatents

    Jefferson, S.

    1958-11-11

    An apparatus utilized in introducing tritium gas into envelope of a gas discharge device for the purpose f maintaining the discharge path in ionized condition is described. ln addition to the cathode and anode, the ischarge device contains a zirconium or tantalum ilament arranged for external excitation and a metallic seed containing tritium, and also arranged to have a current passed through it. Initially, the zirconium or tantalum filament is vaporized to deposit its material adjacent the main discharge region. Then the tritium gas is released and, due to its affinity for the first released material, it deposits in the region of the main discharge where it is most effective in maintaining the discharge path in an ionized condition.

  4. Enhancement of the EUV emission of a metallic capillary discharge operated with argon ambient gas

    SciTech Connect

    Chan, L. S. Tan, D. Saboohi, S. Yap, S. L. Wong, C. S.

    2014-03-05

    In this work, the metallic capillary discharge is operated with two different ambients: air and argon. In the experiments reported here, the chamber is first evacuated to 10{sup −5} mbar. The discharge is initiated by the transient hollow cathode effect generated electron beam, with either air ambient or argon ambient at 10{sup −4} mbar. The bombardment of electron beam at the tip of the stainless steel anode gives rise to a metallic vapor, which is injected into the capillary and initiates the main discharge through the capillary. The EUV emission is measured for different discharge voltages for both conditions and compared. It is found that the metallic capillary discharge with argon ambientis able to produce higher EUV energy compared to that with air ambient.

  5. Axial mercury segregation in direct current operated low-pressure argon mercury gas discharges: Part I. Experimental

    NASA Astrophysics Data System (ADS)

    Gielen, John W. A. M.; de Groot, Simon; van der Mullen, Joost J. A. M.

    2004-07-01

    Due to cataphoresis, axial segregation of mercury will occur when the gas discharge of a fluorescent lamp is operated by means of a direct current. A consequence of this is a non-uniform axial luminance distribution along the lamp. To determine the degree of axial mercury segregation experimentally, axial luminance distributions have been measured which are converted into axial mercury vapour pressure distributions by an appropriate calibration method. The mercury segregation has been investigated for variations in lamp tube radius (3.6-4.8 mm), argon buffer gas pressure (200-600 Pa) and lamp current (100-250 mA) at mercury vapour pressures set at the anode in the range from 0.2 to 9.0 Pa. From the experiments it has been concluded that the mercury vapour pressure gradient at any axial position for a certain lamp tube diameter, argon pressure and lamp current depends on the local mercury vapour pressure. This observation is in contrast to assumptions made in earlier modelling publications in which one mercury vapour pressure gradient is used for all axial positions. By applying a full factorial design, an empirical relation of the mercury segregation is found for any set of parameters inside the investigated parameter ranges.

  6. 46 CFR 153.964 - Discharge by gas pressurization.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Discharge by gas pressurization. 153.964 Section 153.964... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Operations Cargo Transfer Procedures § 153.964 Discharge by gas pressurization. The person in charge of cargo transfer may not...

  7. 46 CFR 153.964 - Discharge by gas pressurization.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Discharge by gas pressurization. 153.964 Section 153.964... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Operations Cargo Transfer Procedures § 153.964 Discharge by gas pressurization. The person in charge of cargo transfer may not...

  8. 46 CFR 153.964 - Discharge by gas pressurization.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Discharge by gas pressurization. 153.964 Section 153.964... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Operations Cargo Transfer Procedures § 153.964 Discharge by gas pressurization. The person in charge of cargo transfer may not...

  9. 46 CFR 154.1838 - Discharge by gas pressurization.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Discharge by gas pressurization. 154.1838 Section 154... SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Operations § 154.1838 Discharge by gas pressurization. The person in charge of cargo transfer may not authorize cargo discharge by...

  10. 46 CFR 154.1838 - Discharge by gas pressurization.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Discharge by gas pressurization. 154.1838 Section 154... SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Operations § 154.1838 Discharge by gas pressurization. The person in charge of cargo transfer may not authorize cargo discharge by...

  11. 46 CFR 154.1838 - Discharge by gas pressurization.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Discharge by gas pressurization. 154.1838 Section 154... SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Operations § 154.1838 Discharge by gas pressurization. The person in charge of cargo transfer may not authorize cargo discharge by...

  12. Ternary gas mixture for diffuse discharge switch

    DOEpatents

    Christophorou, Loucas G.; Hunter, Scott R.

    1988-01-01

    A new diffuse discharge gas switch wherein a mixture of gases is used to take advantage of desirable properties of the respective gases. There is a conducting gas, an insulating gas, and a third gas that has low ionization energy resulting in a net increase in the number of electrons available to produce a current.

  13. A gas discharge lamp for the extreme ultraviolet.

    PubMed

    Nicholson, A J

    1970-05-01

    A gas discharge lamp is described suitable for producing the many-lined spectrum of hydrogen (85-160 nm) and the Hopfield continuum in helium (60-100 nm). It was designed for use with a window-less monochromator to study photoionization and operates at pressures below 50 Torr. The hydrogen lamp has a mode of operation which concentrates the discharge into the monochromator entrance slit.

  14. The effect of the operation modes of a gas discharge low-pressure amalgam lamp on the intensity of generation of 185 nm UV vacuum radiation

    SciTech Connect

    Vasilyak, L. M.; Drozdov, L. A. Kostyuchenko, S. V.; Sokolov, D. V.; Kudryavtsev, N. N.; Sobur, D. A.

    2011-12-15

    The effect of the discharge current, mercury vapor pressure, and the inert gas pressure on the intensity and efficiency of the 185 nm line generation are considered. The spectra of the UV radiation (vacuum ultraviolet) transmission by protective coatings from the oxides of rare earth metals and aluminum are investigated.

  15. Laser diagnostics of gas discharge tubes

    NASA Astrophysics Data System (ADS)

    Stroke, H. H.

    1988-03-01

    The project was set up to develop the basic instrumentation and methods for optical diagnostics of plasmas. Specifically, the work was to permit the measurement of the radial distribution of atomic and ionic species in gas discharge tubes as exemplified by household fluorescent lamps. The aim is obviously to attempt to increase the efficiency by control of the discharge parameters. This report describes the system and results.

  16. Multiplex electric discharge gas laser system

    NASA Technical Reports Server (NTRS)

    Laudenslager, James B. (Inventor); Pacala, Thomas J. (Inventor)

    1987-01-01

    A multiple pulse electric discharge gas laser system is described in which a plurality of pulsed electric discharge gas lasers are supported in a common housing. Each laser is supplied with excitation pulses from a separate power supply. A controller, which may be a microprocessor, is connected to each power supply for controlling the application of excitation pulses to each laser so that the lasers can be fired simultaneously or in any desired sequence. The output light beams from the individual lasers may be combined or utilized independently, depending on the desired application. The individual lasers may include multiple pairs of discharge electrodes with a separate power supply connected across each electrode pair so that multiple light output beams can be generated from a single laser tube and combined or utilized separately.

  17. GAS DISCHARGE SWITCH EVALUATION FOR RHIC BEAM ABORT KICKER APPLICATION.

    SciTech Connect

    ZHANG,W.; SANDBERG,J.; SHELDRAKE,R.; PIRRIE,C.

    2002-06-30

    A gas discharge switch EEV HX3002 is being evaluated at Brookhaven National Laboratory as a possible candidate of RHIC Beam Abort Kicker modulator main switch. At higher beam energy and higher beam intensity, the switch stability becomes very crucial. The hollow anode thyratron used in the existing system is not rated for long reverse current conduction. The reverse voltage arcing caused thyratron hold-off voltage de-rating has been the main limitation of the system operation. To improve the system reliability, a new type of gas discharge switch has been suggested by Marconi Applied Technology for its reverse conducting capability.

  18. METHOD AND APPARATUS FOR PRODUCING INTENSE ENERGETIC GAS DISCHARGES

    DOEpatents

    Bell, P.R.; Luce, J.S.

    1960-01-01

    A device for producing an energetic gas arc discharge employing the use of gas-fed hollow cathode and anode electrodes is reported. The rate of feed of the gas to the electrodes is regulated to cause complete space charge neutralization to occur within the electrodes. The arc discharge is closely fitted within at least one of the electrodes so tint the gas fed to this electrode is substantially completely ionized before it is emitted into the vacuum chamber. It is this electrode design and the axial potential gradient that exists in the arc which permits the arc to be operated in low pressures and at volthges and currents that permit the arc to be energetic. The use of the large number of energetic ions that are accelerated toward the cathode as a propulsion device for a space vehicle is set forth.

  19. Role of powering geometries and sheath gas composition on operation characteristics and the optical emission in the liquid sampling-atmospheric pressure glow discharge

    NASA Astrophysics Data System (ADS)

    Davis, W. Clay; Marcus, R. Kenneth

    2002-09-01

    Characterization of the liquid sampling-atmospheric pressure glow discharge optical emission spectroscopy (LS-APGD-OES) source is described with regards to applications in low-flow separations such as capillary liquid chromatography and electrophoresis. Four powering modes are investigated, including the effects of the individual modes on current-voltage characteristics, analyte emission response, and temporal broadening of flow injection profiles. A concentric sheath gas is employed to stabilize the solution delivery at low liquid flow rates. Sheath gas composition (N 2 or He) effects analyte emission responses as well as gas phase rotational and excitation temperatures. The respective powering modes both measures of temperature, with the OH rotational gas temperatures ranging from ˜2100 to 3000 K and the Fe (I) excitation temperatures ranging from ˜2400 to 3600 K. Rotational temperature values increase slightly when helium is employed as a sheath gas as opposed to nitrogen, with the corresponding excitation temperatures increasing somewhat as well. Analytical response curves for Na and Hg in the various powering modes demonstrate good linearity, with the limits of detection for the analytes found to be on the order of ˜4-10 ppm for 5 μl injections; equating to absolute detection limits of between 20 and 45 ng. It is believed that the approach demonstrated here suggests further improvements that will permit applications in a wide variety of aqueous solution analyses where low-flow rates and limited volumes are encountered.

  20. Research on Modern Gas Discharge Light Sources

    NASA Astrophysics Data System (ADS)

    Born, M.; Markus, T.

    This article gives an overview of today's gas discharge light sources and their application fields with focus on research aspects. In Sect. 15.1 of this chapter, an introduction to electric light sources, the lighting market and related research topics is outlined. Due to the complexity of the subject, we have focused on selected topics in the field of high intensity discharge (HID) lamps since these represent an essential part of modern lamp research. The working principle and light technical properties of HID lamps are described in Sect. 15.2. Physical and thermochemical modelling procedures and tools as well as experimental analysis are discussed in Sects. 15.3 and 15.4, respectively. These tools result in a detailed scientific insight into the complexity of real discharge lamps. In particular, analysis and modelling are the keys for further improvement and development of existing and new products.

  1. Low-voltage gas-discharge device

    DOEpatents

    Kovarik, V.J.; Hershcovitch, A.; Prelec, K.

    1982-06-08

    An electronic device of the type wherein current flow is conducted by an ionized gas comprising a cathode of the type heated by ionic bombardment, an anode, means for maintaining a predetermined pressure in the region between the anode and the cathode and means for maintaining a field in the region is described. The field, which is preferably a combined magnetic and electric field, is oriented so that the mean distance traveled by electrons before reaching the anode is increased. Because of this increased distance traveled electrons moving to the anode will ionize a large number of gas atoms, thus reducing the voltage necessary to initiate gas breakdown. In a preferred embodiment the anode is a main hollow cathode and the cathode is a smaller igniter hollow cathode located within and coaxial with the main hollow cathode. An axial magnetic field is provided in the region between the hollow cathodes in order to facilitate gas breakdown in that region and initiate plasma discharge from the main hollow cathode.

  2. Environmental and economic assessment of discharges from Gulf of Mexico Region Oil and Gas Operations. Quarterly technical progress report, 1 October--31 December 1993

    SciTech Connect

    Gettleson, D.A.

    1994-01-28

    Task 2 (Preparation of the Sampling and Analysis Plan) activities involved the incorporation of the offshore site selection process into the Sampling and Analysis Plan. Task 3 (Environmental Field Sampling and Analysis of NORM, Heavy Metals, and Organics) work included making decisions on tissue analyses and performing analyses of water and sediment samples. Task 4 (Monitoring of the Recovery of Impacted Wetland and Open Bay Produced Water Discharge Sites in Coastal Louisiana and Texas) activities involved the completion of the spring benthos samples collection on pre-termination samples at Four Isle Dome and the first post-termination samples at Delacroix Island. Task 5 (Assessment of Economic Impacts of Offshore and Coastal Discharge Requirements on Present and Future Operations in the Gum of Mexico Region) activities included continued work on development of a base case production forecast, modeling future production, and determining economic impact of treatment technologies. Task 6 (Synthesis of Gulf of Mexico Seafood Consumption and Use Patterns) work involved the completion of the fall survey season and the initiation of the survey data assembly. Task 7 (Technology Transfer Plan) activities included presentations at the Society of Environmental Toxicology and Chemistry annual meeting and Minerals Management Service Information Transfer Meeting. Task 8 (Project Management and Deliverables) activities involved the submission of the necessary reports and routine management.

  3. Gas chemical studies using corona discharge reactors

    NASA Astrophysics Data System (ADS)

    Schulze, P.; Stankiewicz, A.; Aicher, M.; Mattner, M.; Ulrich, A.

    2010-12-01

    Corona discharges with voltages up to 60 kV (DC) were studied with the aim to induce chemical reactions in flue gases at atmospheric pressure. Various plasma reactors with different geometries of multi-needle arrays were tested. The power input was optimised by studying the electrical parameters of the set-up systematically. Both, solid and liquid electrodes were used in combination with the needle arrays. A precise positioning of the corona needles allowed operation without a ballast resistor. Formation rates for CO and the sum of NO2 and O3 are reported and discussed. Three catalytic anode-coatings were tested for their potential to decompose carbon dioxide.

  4. 46 CFR 153.964 - Discharge by gas pressurization.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... authorize cargo discharge by gas pressurization unless: (a) The tank to be offloaded has an SR or PV venting system; (b) The pressurization medium is either the cargo vapor or a nonflammable, nontoxic gas inert to...

  5. Discharge source with gas curtain for protecting optics from particles

    DOEpatents

    Fornaciari, Neal R.; Kanouff, Michael P.

    2004-03-30

    A gas curtain device is employed to deflect debris that is generated by an extreme ultraviolet and soft x-ray radiation discharge source such as an electric discharge plasma source. The gas curtain device projects a stream of gas over the path of the radiation to deflect debris particles into a direction that is different from that of the path of the radiation. The gas curtain can be employed to prevent debris accumulation on the optics used in photolithography.

  6. Self-organization of intense light within erosive gas discharges

    NASA Astrophysics Data System (ADS)

    Torchigin, V. P.; Torchigin, A. V.

    2007-01-01

    Process of appearance of fire balls at gas discharges is considered. It is shown that the intense white light radiated by atoms excited at gas discharge is subject to self-organization in such a way that miniature ball lightnings appear.

  7. Battling Bacterial Biofilms with Gas Discharge Plasma

    NASA Astrophysics Data System (ADS)

    Zelaya, Anna; Vandervoort, Kurt; Brelles-Mariño, Graciela

    Most studies dealing with growth and physiology of bacteria have been carried out using free-living cells. However, most bacteria live in communities referred to as biofilms where cooperative interactions among their members make conventional methods of controlling microbial growth often ineffective. The use of gas discharge plasmas represents an alternative to traditional decontamination/sterilization methods. We studied biofilms using two organisms, Chromobacterium violaceum and Pseudomonas aeruginosa. With the first organism we demonstrated almost complete loss of cell culturability after a 5-min plasma treatment. However, additional determinations showed that non-culturable cells were still alive after short exposure times. We have recently reported the effect of plasma on P. aeruginosa biofilms grown on borosilicate coupons. In this paper, we present results for plasma treatments of 1-, 3-, and 7-day old P. aeruginosa biofilms grown on polycarbonate or stainless-steel coupons. Results indicate nearly 100% of ­biofilm inactivation after 5 min of exposure with similar inactivation kinetics for 1-, 3-, and 7-day-old biofilms, and for both materials used. The inactivation kinetics is similar for both organisms, suggesting that the method is useful regardless of the type of biofilm. AFM images show changes in biofilm structure for various plasma exposure times.

  8. Sensitive glow discharge ion source for aerosol and gas analysis

    DOEpatents

    Reilly, Peter T. A.

    2007-08-14

    A high sensitivity glow discharge ion source system for analyzing particles includes an aerodynamic lens having a plurality of constrictions for receiving an aerosol including at least one analyte particle in a carrier gas and focusing the analyte particles into a collimated particle beam. A separator separates the carrier gas from the analyte particle beam, wherein the analyte particle beam or vapors derived from the analyte particle beam are selectively transmitted out of from the separator. A glow discharge ionization source includes a discharge chamber having an entrance orifice for receiving the analyte particle beam or analyte vapors, and a target electrode and discharge electrode therein. An electric field applied between the target electrode and discharge electrode generates an analyte ion stream from the analyte vapors, which is directed out of the discharge chamber through an exit orifice, such as to a mass spectrometer. High analyte sensitivity is obtained by pumping the discharge chamber exclusively through the exit orifice and the entrance orifice.

  9. Deflagration-to-Detonation Transition Control by Nanosecond Gas Discharges

    DTIC Science & Technology

    2008-04-07

    Report 3. DATES COVERED (From – To) 1 April 2007 - 18 August 09 4. TITLE AND SUBTITLE Deflagration-To- Detonation Transition Control By Nanosecond...SUPPLEMENTARY NOTES 14. ABSTRACT During the current project, an extensive experimental study of detonation initiation by high{voltage...nanosecond gas discharges has been performed in a smooth detonation tube with different discharge chambers and various discharge cell numbers. The chambers

  10. Atmospheric pressure helium afterglow discharge detector for gas chromatography

    DOEpatents

    Rice, G.; D'Silva, A.P.; Fassel, V.A.

    1985-04-05

    An apparatus for providing a simple, low-frequency, electrodeless discharge system for atmospheric pressure afterglow generation. A single quartz tube through which a gas mixture is passed is extended beyond a concentric electrode positioned thereabout. A grounding rod is placed directly above the tube outlet to permit optical viewing of the discharge between the electrodes.

  11. Atmospheric pressure helium afterglow discharge detector for gas chromatography

    DOEpatents

    Rice, Gary; D'Silva, Arthur P.; Fassel, Velmer A.

    1986-05-06

    An apparatus for providing a simple, low-frequency electrodeless discharge system for atmospheric pressure afterglow generation. A single quartz tube through which a gas mixture is passed is extended beyond a concentric electrode positioned thereabout. A grounding rod is placed directly above the tube outlet to permit optical viewing of the discharge between the electrodes.

  12. Radionuclides, Metals, and Hydrocarbons in Oil and Gas Operational Discharges and Environmental Samples Associated with Offshore Production Facilities on the Texas/Louisiana Continental Shelf with an Environmental Assessment of Metals and Hydrocarbons.

    SciTech Connect

    NONE

    1997-06-01

    This report presents concentrations of radionuclides, metals, and hydrocarbons in samples of produced water and produced sand from oil and gas production platforms located offshore Texas and Louisiana. concentrations in produced water discharge plume / receiving water, ambient seawater, sediment, interstitial water, and marine animal tissue samples collected in the vicinity of discharging platforms and reference sites distant from discharges are also reported and discussed. An environmental risk assessment is made on the basis of the concentration of metals and hydrocarbons determined in the samples.

  13. Radionuclides, Metals, and Hydrocarbons in Oil and Gas Operational Discharges and Environmental Samples Associated with Offshore Production Facilities on the Texas/Louisiana Continental Shelf with an Environmental Assessment of Metals and Hydrocarbons

    SciTech Connect

    Continental Shelf Associates, Inc.

    1999-08-16

    This report presents concentrations of radionuclides, metals, and hydrocarbons in samples of produced water and produced sand from oil and gas production platforms located offshore Texas and Louisiana. Concentrations in produced water discharge plume/receiving water, ambient seawater, sediment, interstitial water, and marine animal tissue samples collected in the vicinity of discharging platforms and reference sites distant from discharges are also reported and discussed. An environmental risk assessment is made on the basis of the concentrations of metals and hydrocarbons determined in the samples.

  14. Periodically Discharging, Gas-Coalescing Filter

    NASA Technical Reports Server (NTRS)

    Carter, Donald Layne; Holder, Donald W.

    2006-01-01

    A proposed device would remove bubbles of gas from a stream of liquid (typically water), accumulate the gas, and periodically release the gas, in bulk, back into the stream. The device is intended for use in a flow system (1) in which there is a requirement to supply bubble-free water to a downstream subsystem and (2) that includes a sensor and valves, just upstream of the subsystem, for sensing bubbles and diverting the flow from the subsystem until the water stream is again free of bubbles. By coalescing the gas bubbles and then periodically releasing the accumulated gas, the proposed device would not contribute to net removal of gas from the liquid stream; nevertheless, it would afford an advantage by reducing the frequency with which the diverter valves would have to be activated. The device (see figure) would include an upper and a lower porous membrane made of a hydrophilic material. Both membranes would cover openings in a tube leading to an outlet. These membranes would allow water, but not gas bubbles, to pass through to the interior of the tube. Inside the tube, between the two membranes, there would be a flow restrictor that would play a role described below. Below both membranes there would be a relief valve. Water, possibly containing bubbles, would enter from the top and would pass through either the lower membrane or both membranes, depending how much gas had been accumulated thus far. When the volume of accumulated gas was sufficient to push the top surface of the liquid below the lower porous membrane, water could no longer flow through either membrane toward the outlet. This blockage would cause an increase in back pressure that would cause the relief valve to open. The opening of the relief valve would allow both the water and the bulk-accumulated gas to pass through to the outlet. Once the gas had been pushed out, water would once again flow through both membranes at a much lower pressure drop. The flow restrictor would maintain enough pressure

  15. Gas discharge headlights and visibility of coloured road signs.

    PubMed

    Venkatachalam, Kannan; Smith, George

    2000-01-01

    BACKGROUND: Automotive headlamps mostly use the tungsten halogen bulb but several years ago a new type of headlamp, the gas discharge bulb, was introduced. Because of the different spectral output of this type of lamp, there has been a suggestion that it may affect the colour recognition and sign conspicuity under night-time conditions. In this study, the visibility of the road signs is used to examine the effect of the gas discharge lamp's spectrum compared with that of the conventional halogen headlamp. METHODS: The spectral output of the lamps and the spectral reflectance of common-coloured road signs were measured using a Spectra-Pritchard spectroradiometer. Using luminous reflectance data, chromaticity co-ordinates and the colorimetric shift of the road signs, when illuminated by gas discharge lamps, were plotted using CIE x,y co-ordinate system. Colour rendering indices of the lamp were calculated using Munsell samples and road signs as proscribed by the CIE Publication. In addition, the visibility index of the road signs was calculated using Adrian's 'Visibility of Target' model. RESULTS: The gas discharge headlamp has more energy in the blue region and less energy in the red region of the spectrum than the halogen headlamp. The general colour rendering index of the gas discharge lamp is higher than that of the halogen lamp. When compared with daylight, all coloured road signs used in this study have less colorimetric shift when illuminated by the gas discharge headlamp than by the halogen headlamp. CONCLUSION: The result indicates that the gas discharge lamp, while having a very different spectrum from daylight or tungsten halogen lamps, should not have a deleterious effect on sign detection or recognition, when compared to daylight or tungsten halogen lamps.

  16. Gas mixture for diffuse-discharge switch

    DOEpatents

    Christophorou, Loucas G.; Carter, James G.; Hunter, Scott R.

    1984-01-01

    Gaseous medium in a diffuse-discharge switch of a high-energy pulse generator is formed of argon combined with a compound selected from the group consisting of CF.sub.4, C.sub.2 F.sub.6, C.sub.3 F.sub.8, n-C.sub.4 F.sub.10, WF.sub.6, (CF.sub.3).sub.2 S and (CF.sub.3).sub.2 O.

  17. Gas mixture for diffuse-discharge switch

    DOEpatents

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

    1982-08-31

    Gaseous medium in a diffuse-discharge switch of a high-energy pulse generator is formed of argon combined with a compound selected from the group consisting of CF/sub 4/, C/sub 2/F/sub 6/, C/sub 3/F/sub 8/, n-C/sub 4/F/sub 10/, WF/sub 6/, (CF/sub 3/)/sub 2/S and (CF/sub 3/)/sub 2/O.

  18. Recent studies on nanosecond-timescale pressurized gas discharges

    SciTech Connect

    Yatom, S.; Shlapakovski, A.; Beilin, L.

    2016-10-05

    The results of recent experimental and numerical studies of nanosecond high-voltage discharges in pressurized gases are reviewed. The discharges were ignited in a diode filled by different gases within a wide range of pressures by an applied pulsed voltage or by a laser pulse in the gas-filled charged resonant microwave cavity. Fast-framing imaging of light emission, optical emission spectroscopy, X-ray foil spectrometry and coherent anti-Stokes Raman scattering were used to study temporal and spatial evolution of the discharge plasma density and temperature, energy distribution function of runaway electrons and dynamics of the electric field in the plasma channel. The resultsmore » obtained allow a deeper understanding of discharge dynamical properties in the nanosecond timescale, which is important for various applications of these types of discharges in pressurized gases.« less

  19. Recent studies on nanosecond-timescale pressurized gas discharges

    SciTech Connect

    Yatom, S.; Shlapakovski, A.; Beilin, L.; Stambulchik, E.; Tskhai, S.; Krasik, Ya E.

    2016-10-05

    The results of recent experimental and numerical studies of nanosecond high-voltage discharges in pressurized gases are reviewed. The discharges were ignited in a diode filled by different gases within a wide range of pressures by an applied pulsed voltage or by a laser pulse in the gas-filled charged resonant microwave cavity. Fast-framing imaging of light emission, optical emission spectroscopy, X-ray foil spectrometry and coherent anti-Stokes Raman scattering were used to study temporal and spatial evolution of the discharge plasma density and temperature, energy distribution function of runaway electrons and dynamics of the electric field in the plasma channel. The results obtained allow a deeper understanding of discharge dynamical properties in the nanosecond timescale, which is important for various applications of these types of discharges in pressurized gases.

  20. Analytical model for low-pressure gas discharges: application to the Hg + Ar discharge.

    PubMed

    Lama, W L; Gallo, C F; Hammond, T J; Walsh, P J

    1982-05-15

    A general technique for analyzing complicated gas discharges has been developed and applied to the Hg + Ar (fluorescent lamp) discharge. The theoretical model includes electron excitation and deexcitation, two-state ionization through a saturated metastable level, and proper treatment of the self-absorption of the resonance radiation. The analysis yields simple analytic expressions for the electron temperature, the resonance radiation, and the electric field. When applied to Hg + Ar discharges, these analytic expressions yield good quantitative agreement with the available absolute data on the dependence of the electron temperature, the Hg 2537-A radiation, and the electric field on mercury pressure and current.

  1. Method and apparatus for processing exhaust gas with corona discharge

    DOEpatents

    Barlow, Stephan E.; Orlando, Thomas M.; Tonkyn, Russell G.

    1999-01-01

    The present invention is placing a catalyst coating upon surfaces surrounding a volume containing corona discharge. In addition, the electrodes are coated with a robust dielectric material. Further, the electrodes are arranged so that at least a surface portion of each electrode extends into a flow path of the exhaust gas to be treated and there is only exhaust gas in the volume between each pair of electrodes.

  2. Method and apparatus for processing exhaust gas with corona discharge

    DOEpatents

    Barlow, S.E.; Orlando, T.M.; Tonkyn, R.G.

    1999-06-22

    The present invention is placing a catalyst coating upon surfaces surrounding a volume containing corona discharge. In addition, the electrodes are coated with a robust dielectric material. Further, the electrodes are arranged so that at least a surface portion of each electrode extends into a flow path of the exhaust gas to be treated and there is only exhaust gas in the volume between each pair of electrodes. 12 figs.

  3. The transition of a multipactor to a low-pressure gas discharge

    SciTech Connect

    Hoehn, F.; Jacob, W.; Beckmann, R.; Wilhelm, R.

    1997-04-01

    Multipactor discharges can cause severe problems in high voltage rf systems like rf antennae or transmission lines of ion cyclotron resonance heating (ICRH) in nuclear fusion devices, where they may initiate gas breakdown. To study this eventual transition from a starting multipactor into an ordinary rf discharge detailed investigations were performed using a parallel plate geometry, 50 MHz operating frequency and up to one kilovolt rf amplitude. Measurements of electric data (rf amplitude, absorbed and reflected power, discharge current), electronic parameters (electron current density and energy distribution) and light emission were used for characterization. As a main result a new type of well defined discharge regime was identified, which seems important for the transition from multipactor into gas breakdown in rf devices. {copyright} {ital 1997 American Institute of Physics.}

  4. Direct-current converter for gas-discharge lamps

    NASA Technical Reports Server (NTRS)

    Lutus, P.

    1980-01-01

    Metal/halide and similar gas-discharge lamps are powered from low-voltage dc source using small efficient converter. Converter is useful whenever 60-cycle ac power is not available or where space and weight allocations are limited. Possible applications are offshore platforms, mobile homes, and emergency lighting. Design innovations give supply high reliability and efficiency up to 75 percent.

  5. Emission Characteristics of Xenon and Xenon-Rare Gas Dielectric Barrier Discharge Fluorescent Lamps

    NASA Astrophysics Data System (ADS)

    Jinno, Masafumi; Motomura, Hideki; Loo, Ka Hong; Aono, Masaharu

    The profile of vacuum ultraviolet (VUV), visible and near IR emissions of xenon and xenon-rare gas pulsed discharge fluorescent lamps were observed as a fundamental research on developing a mercury-free fluorescent lamp. All lamps were operated by pulsed dielectric barrier discharge (DBD). As the pulse width decreases, higher intensity of VUV emissions is obtained, while luminance and efficacy also increase. As the pulse frequency increases, the intensity of VUV emissions increases, however the radiative output per one pulse period decreases and the efficacy decreases. The decay time of VUV emissions which are exciting a phosphor, can be controlled by introducing a rare-gas mixture into xenon.

  6. Comparison of electrical and optical characteristics in gas-phase and gas-liquid phase discharges

    NASA Astrophysics Data System (ADS)

    Qazi, H. I. A.; Nie, Qiu-Yue; Li, He-Ping; Zhang, Xiao-Fei; Bao, Cheng-Yu

    2015-12-01

    This paper presents an AC-excited argon discharge generated using a gas-liquid (two-phase) hybrid plasma reactor, which mainly consists of a powered needle electrode enclosed in a conical quartz tube and grounded deionized water electrode. The discharges in the gas-phase, as well as in the two-phase, exhibit two discharge modes, i.e., the low current glow-like diffuse mode and the high current streamer-like constrict mode, with a mode transition, which exhibits a negative resistance of the discharges. The optical emission spectral analysis shows that the stronger diffusion of the water vapor into the discharge region in the two-phase discharges boosts up the generation of OH (A-X) radicals, and consequently, leads to a higher rotational temperature in the water-phase plasma plume than that of the gas-phase discharges. Both the increase of the power input and the decrease of the argon flow rate result in the increase of the rotational temperature in the plasma plume of the water-phase discharge. The stable two-phase discharges with a long plasma plume in the water-phase under a low power input and gas flow rate may show a promising prospect for the degradation of organic pollutants, e.g., printing and dyeing wastewater, in the field of environmental protection.

  7. Investigation Of The High-Voltage Discharge On The Surface Of Gas-Liquid System

    NASA Astrophysics Data System (ADS)

    Nguyen-Kuok, Shi; Morgunov, Aleksandr; Malakhov, Yury; Korotkikh, Ivan

    2016-09-01

    This paper describes an experimental setup for study of physical processes in the high-voltage discharge on the surface of gas-liquid system at atmospheric pressure. Measurements of electrical and optical characteristics of the high-voltage discharge in gas, at the surface of the gas-liquid system and in the electrolyte are obtained. The parameters of the high-voltage discharge and the conditions for its stable operation are presented. Investigations with various electrolytes and cathode assemblies of various materials and sizes were carried out. The installation can be used for the processing and recycling of industrial and chemical liquid waste. Professor of Laboratory of Plasma Physics, National Research University MPEI, Krasnokazarmennya Str.14, 111250, Moscow, Russia.

  8. Pulsed electrical discharge in gas bubbles in water

    NASA Astrophysics Data System (ADS)

    Gershman, Sophia

    A phenomenological picture of pulsed electrical discharge in gas bubbles in water is produced by combining electrical, spectroscopic, and imaging methods. The discharge is generated by applying one microsecond long 5 to 20 kilovolt pulses between the needle and disk electrodes submerged in water. A gas bubble is generated at the tip of the needle electrode. The study includes detailed experimental investigation of the discharge in argon bubbles and a brief look at the discharge in oxygen bubbles. Imaging, electrical characteristics, and time-resolved optical emission data point to a fast streamer propagation mechanism and formation of a plasma channel in the bubble. Spectroscopic methods based on line intensity ratios and Boltzmann plots of line intensities of argon, atomic hydrogen, and argon ions and the examination of molecular emission bands from molecular nitrogen and hydroxyl radicals provide evidence of both fast beam-like electrons and slow thermalized ones with temperatures of 0.6 -- 0.8 electron-volts. The collisional nature of plasma at atmospheric pressure affects the decay rates of optical emission. Spectroscopic study of rotational-vibrational bands of hydroxyl radical and molecular nitrogen gives vibrational and rotational excitation temperatures of the discharge of about 0.9 and 0.1 electron-volt, respectively. Imaging and electrical evidence show that discharge charge is deposited on the bubble wall and water serves as a dielectric barrier for the field strength and time scales of this experiment. Comparing the electrical and imaging information for consecutive pulses applied at a frequency of 1 Hz indicates that each discharge proceeds as an entirely new process with no memory of the previous discharge aside from long-lived chemical species, such as ozone and oxygen. Intermediate values for the discharge gap and pulse duration, low repetition rate, and unidirectional character of the applied voltage pulses make the discharge process here unique

  9. Spots and patterns on electrodes of gas discharges

    NASA Astrophysics Data System (ADS)

    Benilov, Mikhail

    2015-09-01

    Concentration of electrical current onto the surface of electrodes of gas discharges in well-defined regions, or current spots, is often the rule rather than the exception. These spots occur on otherwise uniform electrode surfaces, a regime where one might expect a uniform distribution of current over the surface. In many cases, multiple spots may appear, forming beautiful patterns and surprising the observer. Important advances have been attained in the last 15 years in experimental investigation, understanding, and modelling of spots and patterns in discharges of different types, in particular, high-pressure arc discharges, dc glow discharges, and barrier discharges. It became clear that in many, if not most, cases there is no need to look for special physical mechanisms responsible for the formation of spots or patterns on uniform electrode surfaces: the spots or patterns originate in self-organization caused by (nonlinear) interaction of well-known mechanisms. In particular, standard mechanisms of near-cathode space-charge sheath are sufficient to produce self-organization, and it is this kind of self-organization that gives rise to cathode spots in low-current high-pressure arcs and normal spots and patterns of spots on cathodes of dc glow discharges. It was shown that spots and patterns on electrodes of gas discharges, being self-organization phenomena, are inherently related to multiple solutions, with one of the solutions describing a mode with a uniform distribution of current over the electrode surface and the others describing regimes with different spot patterns. These multiple solutions exist even in the most basic self-consistent models of gas discharges. In particular, multiple solutions have been found for dc glow discharges; the fact rather surprising by itself, given that such discharges have been under intensive theoretical investigation for many years. A concise review of the above-described advances is given in this talk. Work supported by FCT

  10. Gas-dynamic effects in the interaction of a motionless optical pulsating discharge with gas

    SciTech Connect

    Tishchenko, V N; Grachev, G N; Smirnov, A L; Pavlov, A A; Pavlov, A A; Golubev, M P

    2008-01-31

    The effect of energy removal from the combustion zone of a motionless optical pulsating discharge in the horizontal direction along the axis of a repetitively pulsed laser beam producing the discharge is discovered. The directivity diagram of a hot gas flow is formed during the action of hundreds of pulses. The effect is observed for short pulse durations, when the discharge efficiently generates shock waves. For long pulse durations, the heated gas propagates upward, as in a thermal source. (laser applications and other topics in quantum electronics)

  11. Flow shaping using three-dimensional microscale gas discharge

    NASA Astrophysics Data System (ADS)

    Wang, Chin-Cheng; Roy, Subrata

    2009-08-01

    We introduce a flow shaping mechanism using surface compliant microscale gas discharge. A three-dimensional finite element-based multiscale ionized gas flow code is utilized to analyze charge separation, potential distribution, and flow inducement mechanism. For the case of quiescent flow, a horseshoe-shaped plasma generator is introduced. Due to its unusual shape, the three-dimensional electric force excites a pinching effect on the fluid inside selectively powered electrode arc. Such effect is capable of tripping the flow-ejecting fluid normal to the plane of the actuator and thus can be very useful for many applications.

  12. Emitter depletion studies on electrodes of 50 Hz mercury/noble gas discharge lamps during ignition

    NASA Astrophysics Data System (ADS)

    van den Hoek, W. J.; Thijssen, T. L. G.; van der Heijden, A. J. H.; Buijsse, B.; Haverlag, M.

    2002-07-01

    The depletion of emitter from the oxide cathodes during the glow switch starting of the discharge in 50 Hz operated low-pressure mercury/noble gas discharge lamps (fluorescent lamps) has been studied. It follows from pulse ignition studies and computer-controlled ignition experiments that two plasma modes exist during ignition: a glow discharge and a vapour-arc discharge. The occurrence of these modes depends on the point of interruption with respect to the phase of the 50 Hz preheat current. The vapour arc appears to be the dominant mechanism of emitter depletion. The average emitter loss per vapour-arc pulse has been quantified by radioactive Ba tracer experiments. The nature of the vapour arc has been studied by fast photography and SEM. The vapour arc involves dielectric breakdown over the non-conducting oxide mass and gives rise to explosive emitter vapourization.

  13. Feedback model of secondary electron emission in DC gas discharge plasmas

    NASA Astrophysics Data System (ADS)

    Saravanan, ARUMUGAM; Prince, ALEX; Suraj, Kumar SINHA

    2018-01-01

    Feedback is said to exist in any amplifier when the fraction of output power in fed back as an input. Similarly, in gaseous discharge ions that incident on the cathode act as a natural feedback element to stabilize and self sustain the discharge. The present investigation is intended to emphasize the feedback nature of ions that emits secondary electrons (SEs) from the cathode surface in DC gas discharges. The average number of SEs emitted per incident ion and non ionic species (energetic neutrals, metastables and photons) which results from ion is defined as effective secondary electron emission coefficient (ESEEC,{γ }{{E}}). In this study, we derive an analytic expression that corroborates the relation between {γ }{{E}} and power influx by ion to the cathode based on the feedback theory of an amplifier. In addition, experimentally, we confirmed the typical positive feedback nature of SEE from the cathode in argon DC glow discharges. The experiment is done for three different cathode material of same dimension (tungsten (W), copper (Cu) and brass) under identical discharge conditions (pressure: 0.45 mbar, cathode bias: ‑600 V, discharge gab: 15 cm and operating gas: argon). Further, we found that the {γ }{{E}} value of these cathode material controls the amount of feedback power given by ions. The difference in feedback leads different final output i.e the power carried by ion at cathode ({P}{{i}}{\\prime }{| }{{C}}). The experimentally obtained value of {P}{{i}}{\\prime }{| }{{C}} is 4.28 W, 6.87 W and 9.26 W respectively for W, Cu and brass. In addition, the present investigation reveals that the amount of feedback power in a DC gas discharges not only affect the fraction of power fed back to the cathode but also the entire characteristics of the discharge.

  14. Pulsed Gas Lasers Pumped by a Runaway Electron Initiated Discharge

    NASA Astrophysics Data System (ADS)

    Panchenko, A. N.; Tarasenko, V. F.; Panchenko, N. A.

    2017-12-01

    The generation parameters are investigated in a runaway electron preionized diffuse discharge (REP DD). Laser generation is produced in different spectral bands from the IR to VUV range. New modes of the nitrogen laser operation are obtained. Ultimate efficiencies of N2- and nonchain HF(DF)-lasers are achieved. A possibility of increasing the pulse durations of XeF-, KrF-, ArF- and VUV F2- lasers (157 nm) in an oscillating REP DD is shown. The efficiencies of VUV- and UV-generation comparable with that of a laser pumped by a self-sustained volume discharge with preionization are gained.

  15. Particle-in-Cell Simulation of Electrical Gas Discharges

    NASA Astrophysics Data System (ADS)

    Soria, C.; Pontiga, F.; Castellanos, A.

    2001-07-01

    A fluid particle-in-cell (PIC) model is proposed for the numerical solution of the continuity equation of electrons and ions in transient electrical gas discharges. The reactions occurring in a gaseous discharge, such as ionization of neutral molecules, electron attachment, and recombination between electrons and ions, are implemented through the variation of the mass of the computational particles used in the simulation. Two different forms of interpolation of the gain/loss rates from the grid to the computational particles are suggested, depending on the reaction type. The PIC model is first applied to the problem of an idealized electron avalanche in a non-attaching gas. This problem possesses an analytical solution where the electron density grows exponentially in time as it propagates, but keeps the square-wave form of the initial electron distribution. This problem is used to validate the optimum interpolation of the gain/loss rate and to analyze the effect of the mass matrix formulation of the PIC model. Then, a more realistic model is applied to simulate the propagation of a Trichel pulse between a sphere and a plate. In this case, the continuity equation for electrons and positive and negative ions, coupled to the Poisson equation, has been solved. This second test has proved the ability of the present numerical method to deal with those discharges dominated by the space charge effect. The results of the PIC simulation are compared with those obtained from the application of a flux-corrected transport method.

  16. Effects of direct current discharge on the spatial distribution of cylindrical inductively-coupled plasma at different gas pressures

    NASA Astrophysics Data System (ADS)

    Yue, HUA; Jian, SONG; Zeyu, HAO; Gailing, ZHANG; Chunsheng, REN

    2018-01-01

    Stable operations of single direct current (DC) discharge, single radio frequency (RF) discharge and DC + RF hybrid discharge are achieved in a specially-designed DC enhanced inductively-coupled plasma (DCE-ICP) source. Their plasma characteristics, such as electron density, electron temperature and the electron density spatial distribution profiles are investigated and compared experimentally at different gas pressures. It is found that under the condition of single RF discharge, the electron density distribution profiles show a ‘convex’ shape and ‘saddle’ shape at gas pressures of 3 mTorr and 150 mTorr respectively. This result can be attributed to the transition of electron kinetics from nonlocal to local kinetics with an increase in gas pressure. Moreover, in the operation of DC + RF hybrid discharge at different gas pressures, the DC discharge has different effects on plasma uniformity. The plasma uniformity can be improved by modulating DC power at a high pressure of 150 mTorr where local electron kinetics is dominant, whereas plasma uniformity deteriorates at a low pressure of 3 mTorr where nonlocal electron kinetics prevails. This phenomenon, as analyzed, is due to the obvious nonlinear enhancement effect of electron density at the chamber center, and the inherent radial distribution difference in the electron density with single RF discharge at different gas pressures.

  17. Decomposition of dimethylamine gas with dielectric barrier discharge.

    PubMed

    Ye, Zhaolian; Zhao, Jie; Huang, Hong ying; Ma, Fei; Zhang, Renxi

    2013-09-15

    The decomposition of dimethylamine (DMA) with gas under high flow rate was investigated with dielectric barrier discharge (DBD) technology. Different parameters including removal efficiency, energy yield, carbon balance and CO2 selectivity, secondary products, as well as pathways and mechanisms of DMA degradation were studied. The experimental results showed that removal efficiency of DMA depended on applied voltage and gas flow rate, but had no obvious correlation with initial concentration. Excellent energy performance was obtained using present DBD technology for DMA abatement. When experiment conditions were controlled at: gas flow rate of 14.9 m(3)/h, initial concentration of 2104 mg/m(3), applied voltage of 4.8 kV, removal efficiency of DMA and energy yield can reach 85.2% and 953.9 g/kWh, respectively. However, carbon balance (around 40%) was not ideal due to shorter residence time (about 0.1s), implying that some additional conditions should be considered to improve the total oxidation of DMA. Moreover, secondary products in outlet gas stream were detected via gas chromatogram-mass spectrum and the amounts of NO3(-) and NO2(-) were analyzed by ion chromatogram. The obtained data demonstrated that NOx might be suppressed due to reductive NH radical form DMA dissociation. The likely reaction pathways and mechanisms for the removal of DMA were suggested based on products analysis. Experimental results demonstrated the application potential of DBD as a clean technology for organic nitrogen-containing gas elimination from gas streams. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Analysis on discharge process of a plasma-jet triggered gas spark switch

    NASA Astrophysics Data System (ADS)

    Weihao, TIE; Cui, MENG; Yuting, ZHANG; Zirang, YAN; Qiaogen, ZHANG

    2018-01-01

    The plasma-jet triggered gas switch (PJTGS) could operate at a low working coefficient with a low jitter. We observed and analyzed the discharge process of the PJTGS at the lowest working coefficient of 47% with the trigger voltage of 40 kV and the pulse energy of 2 J to evaluate the effect of the plasma jet. The temporal and spatial evolution and the optical emission spectrum of the plasma jet were captured. And the spraying delay time and outlet velocity under different gas pressures were investigated. In addition, the particle in cell with Monte Carlo collision was employed to obtain the particle distribution of the plasma jet varying with time. The results show that, the plasma jet generated by spark discharge is sprayed into a spark gap within tens of nanoseconds, and its outlet velocity could reach 104 m s‑1. The plasma jet plays a non-penetrating inducing role in the triggered discharge process of the PJTGS. On the one hand, the plasma jet provides the initial electrons needed by the discharge; on the other hand, a large number of electrons focusing on the head of the plasma jet distort the electric field between the head of the plasma jet and the opposite electrode. Therefore, a fast discharge originated from the plasma jet is induced and quickly bridges two electrodes.

  19. Characterization of the Electrode Erosion by Spectrum Analysis at low Pressure Gas-Discharge Lamps

    NASA Astrophysics Data System (ADS)

    Boubetra, Dj.; Bouafia, M.

    2008-09-01

    The development of highly effective gas-discharge lamps led to a large use of the illuminating engineering. The superiority of the gas-discharge lamps over the conventional lamps expresses itself apart from the luminous efficiency, i.e. the produced light-intensity per fed electrical achievement, particularly in the higher life span (7000-9000 hours). The electrodes near processes have crucial influence on the life span of the light sources of light and the stability of their operation. The erosion behaviour of the electrodes in gas-discharge lamps was the subject of many investigations. An indirect method was described by other investigations. Where the measurement of the absolute alkaline metal atomic demolition is done by means of radioactive tracers. The purpose of these investigations is the regulation of the erosion electrodes in normal fluorescent lamps without intervention in the discharge. The evaporation rates from the observed spectral lines intensity of the cathode materials e.g. the barium and the strontium should make the estimation for the life span possible.

  20. Improving the accuracy of operation coding in surgical discharge summaries

    PubMed Central

    Martinou, Eirini; Shouls, Genevieve; Betambeau, Nadine

    2014-01-01

    Procedural coding in surgical discharge summaries is extremely important; as well as communicating to healthcare staff which procedures have been performed, it also provides information that is used by the hospital's coding department. The OPCS code (Office of Population, Censuses and Surveys Classification of Surgical Operations and Procedures) is used to generate the tariff that allows the hospital to be reimbursed for the procedure. We felt that the OPCS coding on discharge summaries was often incorrect within our breast and endocrine surgery department. A baseline measurement over two months demonstrated that 32% of operations had been incorrectly coded, resulting in an incorrect tariff being applied and an estimated loss to the Trust of £17,000. We developed a simple but specific OPCS coding table in collaboration with the clinical coding team and breast surgeons that summarised all operations performed within our department. This table was disseminated across the team, specifically to the junior doctors who most frequently complete the discharge summaries. Re-audit showed 100% of operations were accurately coded, demonstrating the effectiveness of the coding table. We suggest that specifically designed coding tables be introduced across each surgical department to ensure accurate OPCS codes are used to produce better quality surgical discharge summaries and to ensure correct reimbursement to the Trust. PMID:26734286

  1. CO{sub 2} utilization by gas discharges

    SciTech Connect

    Fotouh, K.H.; Liu, Changjun

    1996-12-31

    Carbon dioxide is the end product to complete combustion of all fossil fuels. The generation of carbon dioxide is the primary cause for the greenhouse effect. However, carbon dioxide is a potential carbon source. To utilize such a plentiful carbon source, it has been considered carbon dioxide as a feedstock for organic synthesis of carbonyl- and carboxyl-containing compounds or as an oxidant for oxidative synthesis of more valuable organics. Gas discharge (glow, corona, arc and silence discharges) is an abundant resource of free radicals. The potential to develop a technique, in which oxidative synthesize of high-valued hydrocarbons together with removalmore » of CO{sub 2}, NO{sub x} and SO{sub x} is very economically attractive. The by-product of such a technique is carbon monoxide, which can be also applied for organic synthesis, e.g., F-T synthesis. In this paper, the results of oxidative methane conversion to ethane and ethylene using CO{sub 2} as an oxidant by streamer corona discharge is reported.« less

  2. Properties of erosive discharge in a gas-dispersion flow

    NASA Astrophysics Data System (ADS)

    Bityurin, V. A.; Velikodnyi, V. Yu.; Samuolis, I. A.

    2009-11-01

    Erosive discharge in the flow of a gas-dispersion mixture (air with dispersed microscopic drops of an electrolyte) has been experimentally studied. The products of erosion were obtained by coating the electrodes with a wax (this method was originally used by N. Tesla). Two phenomena were observed behind the discharge gap, i.e., (i) a linear breakdown in the form of a bead lightning (within 0.5-1 m behind the interelectrode gap) and (ii) the appearance of long-lived plasma formations (plasmoids). Cotton-like wax deposits formed on glass slides were examined in optical microscopes at various magnifications. The propagation of long-lived plasmoids in an applied magnetic field was monitored by a high-speed TV camera. Waveforms of a current transferred by the gas-dispersion flow were measured using a conducting screen. Based on these data, a self-consistent physical model is formulated, which describes the generation, evolution, and decay of the long-lived plasmoids.

  3. [Emission spectroscopy diagnosis of the radicals generated in gas-liquid phases gliding arc discharge].

    PubMed

    Yan, Jian-hua; Dai, Shang-li; Li, Xiao-dong; Tu, Xin; Liu, Ya-na; Cen, Ke-fa

    2008-08-01

    Gas-liquid phases gliding arc discharge has been investigated as a potential treatment technology for liquid phase pollution treatment. To further understand the interaction mechanisms of gas-liquid phase gliding arc degradation process for the wastewater treatment, the characteristics of major reactive species (the OH and NO radicals) in a gas-liquid gliding arc at atmospheric pressure have been investigated by using optical emission spectroscopy. The chemical reactions that may lead to the generation of free radicals in the discharge were discussed. The influence of operating conditions (water feed rate, input voltage etc. ) on the relative intensity of radical emission was studied. The results show that axial evolution of the relative emission intensity of both reactive species exhibit the similar tendency under the same operating conditions. In non-thermodynamic equilibrium region of the arc discharge, the intensities of both radicals increase with the input voltage. In addition, the intensity of OH radical increases with the water feed rate, while the opposition phenomena are observed for NO radical.

  4. Discharge modes of a DC operated atmospheric pressure air plasma jet

    NASA Astrophysics Data System (ADS)

    Kolb, Juergen; Pei, Xuekai; Kredl, Jana; Lu, Xinpei

    2016-09-01

    By flowing air or nitrogen through a microhollow cathode discharge geometry an afterglow plasma jet can be generated at atmospheric pressure in air. The plasma jet has been successfully used for the inactivation of bacteria and yeast. The responsible reaction chemistry is based on the production of high concentrations of nitric oxide. Production yields depend in particular on gas flow rate and energy dissipated in the plasma. The same parameters also determine different modes of operation for the jet. A true DC operation is achieved for low to moderate gas flow rate of about 1 slm and discharge currents on the order of 10 mA. When increasing the gas flow rate to 10 slm the operation is changing to a self-pulsing mode with characteristics similar to the ones observed for a transient spark. By increasing the current a DC operation can be achieved again also at higher gas flow rates. The parameter regimes for different modes of operation can be described by the reduced electric field E/N.

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

    SciTech Connect

    Johnson, Michael J.; Go, David B.

    2015-12-28

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

  6. High-power gas-discharge excimer ArF, KrCl, KrF and XeCl lasers utilising two-component gas mixtures without a buffer gas

    SciTech Connect

    Razhev, A M; Kargapol'tsev, E S; Churkin, D S

    2016-03-31

    Results of an experimental study of the influence of a gas mixture (laser active medium) composition on an output energy and total efficiency of gas-discharge excimer lasers on ArF* (193 nm), KrCl* (222 nm), KrF* (248 nm) and XeCl* (308 nm) molecules operating without a buffer gas are presented. The optimal ratios of gas components (from the viewpoint of a maximum output energy) of an active medium are found, which provide an efficient operation of laser sources. It is experimentally confirmed that for gas-discharge excimer lasers on halogenides of inert gases the presence of a buffer gas in an activemore » medium is not a necessary condition for efficient operation. For the first time, in two-component gas mixtures of repetitively pulsed gas-discharge excimer lasers on electron transitions of excimer molecules ArF*, KrCl*, KrF* and XeCl*, the pulsed energy of laser radiation obtained under pumping by a transverse volume electric discharge in a low-pressure gas mixture without a buffer gas reached up to 170 mJ and a high pulsed output power (of up to 24 MW) was obtained at a FWHM duration of the KrF-laser pulse of 7 ns. The maximal total efficiency obtained in the experiment with two-component gas mixtures of KrF and XeCl lasers was 0.8%. (lasers)« less

  7. Dynamic Reduction Effect of CO2 Gas Discharge in Introducing Electric Vehicles

    NASA Astrophysics Data System (ADS)

    Liu, Bin; Inaba, Tsuginori

    For this study, the dynamic reduction effect of CO2 gas discharge for change from internal combustion engines to electric vehicles, EVs, was investigated quantitatively. The Japanese power generation status, which shows characteristics of electricity generation, and optimized adjustment to electricity demand, load and environment was examined. Based on a CO2 gas discharge basic unit, the estimated reduction quantity of CO2 gas discharge from EVs was calculated. The reduction effect of CO2 gas discharge is expected to be 52% by changing gas-fuelled vehicles to EVs. However, the dynamic differential is only 19% reduction by using the thermal power and -2% if only the coal thermal power is used.

  8. Experimental investigation on the effect of plasma jet in the triggered discharge process of a gas switch

    SciTech Connect

    Tie, W. E-mail: 84470220@qq.com; Liu, S.; Liu, X.; Zhang, Q.

    2016-08-15

    The temporal and spatial evolution of a plasma jet generated by a spark discharge was observed. The electron temperature and density were obtained under different time and gas pressures by optical emission spectroscopy. Moreover, the discharge process of the plasma-jet triggered gas switch was recorded and analyzed at the lowest working coefficient. The results showed that the plasma jet moved forward in a bullet mode, and the advancing velocity increased with the decrease of pressure, and decreased with time growing. At initial time, the maximum velocity of a plasma jet could reach 3.68 × 10{sup 6 }cm/s. The electron temperature decreased from 2.0 eV to 1.3 eV, and the electron density increased from 3.1 × 10{sup 15}/cm{sup 3} to 6.3 × 10{sup 15}/cm{sup 3} at the initial moment as the gas pressure increases from 0.1 MPa to 0.32 MPa. For a two-gap gas switch, the discharge performances were more depended on the second discharge spark gap (gap 2). Because plasma jet promoted the discharge in Gap 2, the gas switch operating in mode II had better triggered discharge characteristics. In the discharge process, the plasma-jet triggering had the effect of non-penetrating inducing, which not only provided initial electrons for reducing statistical lag but also enhanced the local electric field. The discharge was initiated and accelerated from electron avalanche to streamer. Therefore, a fast discharge was occurred in the gas switch.

  9. 21 CFR 1020.20 - Cold-cathode gas discharge tubes.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cold-cathode gas discharge tubes. 1020.20 Section...) RADIOLOGICAL HEALTH PERFORMANCE STANDARDS FOR IONIZING RADIATION EMITTING PRODUCTS § 1020.20 Cold-cathode gas discharge tubes. (a) Applicability. The provisions of this section are applicable to cold-cathode gas...

  10. 21 CFR 1020.20 - Cold-cathode gas discharge tubes.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cold-cathode gas discharge tubes. 1020.20 Section...) RADIOLOGICAL HEALTH PERFORMANCE STANDARDS FOR IONIZING RADIATION EMITTING PRODUCTS § 1020.20 Cold-cathode gas discharge tubes. (a) Applicability. The provisions of this section are applicable to cold-cathode gas...

  11. 21 CFR 1020.20 - Cold-cathode gas discharge tubes.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cold-cathode gas discharge tubes. 1020.20 Section...) RADIOLOGICAL HEALTH PERFORMANCE STANDARDS FOR IONIZING RADIATION EMITTING PRODUCTS § 1020.20 Cold-cathode gas discharge tubes. (a) Applicability. The provisions of this section are applicable to cold-cathode gas...

  12. 21 CFR 1020.20 - Cold-cathode gas discharge tubes.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cold-cathode gas discharge tubes. 1020.20 Section...) RADIOLOGICAL HEALTH PERFORMANCE STANDARDS FOR IONIZING RADIATION EMITTING PRODUCTS § 1020.20 Cold-cathode gas discharge tubes. (a) Applicability. The provisions of this section are applicable to cold-cathode gas...

  13. 21 CFR 1020.20 - Cold-cathode gas discharge tubes.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cold-cathode gas discharge tubes. 1020.20 Section...) RADIOLOGICAL HEALTH PERFORMANCE STANDARDS FOR IONIZING RADIATION EMITTING PRODUCTS § 1020.20 Cold-cathode gas discharge tubes. (a) Applicability. The provisions of this section are applicable to cold-cathode gas...

  14. ORAL ISSUE OF THE JOURNAL "USPEKHI FIZICHESKIKH NAUK": Modeling of gas discharge plasma

    NASA Astrophysics Data System (ADS)

    Smirnov, Boris M.

    2009-06-01

    The condition for the self-maintenance of a gas discharge plasma (GDP) is derived from its ionization balance expressed in the Townsend form and may be used as a definition of a gas discharge plasma in its simplest form. The simple example of a gas discharge plasma in the positive column of a cylindrical discharge tube allows demonstrating a wide variety of possible GDP regimes, revealing a contradiction between simple models used to explain gas discharge regimes and the large number of real processes responsible for the self-maintenance of GDP. The variety of GDP processes also results in a stepwise change of plasma parameters and developing some instabilities as the voltage or discharge current is varied. As a consequence, new forms and new applications of gas discharge arise as technology progresses.

  15. Destruction of Bacterial Biofilms Using Gas Discharge Plasma

    NASA Astrophysics Data System (ADS)

    Abramzon, Nina

    2005-03-01

    Biofilms are bacterial communities embedded in an exopolysaccharidic matrix with a complex architectural structure. Bacteria in biofilms show different properties from those in free life thus, conventional methods of killing bacteria are often ineffective with biofilms. The use of plasmas potentially offers an alternative to conventional sterilization methods since plasmas contain a mixture of charged particles, chemically reactive species, and UV radiation. 4 and 7 day-old biofilms were produced using two bacterial species: Rhizobium gallicum and Chromobacterium violaceum. Gas discharge plasma was produced by using an AtomfloTM reactor (Surfx Technologies) and bacterial biofilms were exposed to it for different periods of time. Our results show that a 10-minute plasma treatment was able to kill 100% of the cells in most cases. Optical emission spectroscopy was used to study plasma composition which is then correlated with the effectiveness of killing. These results indicate the potentiality of plasma as an alternative sterilization method. Supported by CSuperb.

  16. Relaxation of heavy species and gas temperature in the afterglow of a N2 microwave discharge

    NASA Astrophysics Data System (ADS)

    Pintassilgo, Carlos D.; Guerra, Vasco

    2017-10-01

    In this paper we present a self-consistent kinetic model to study the temporal variation of the gas temperature in the afterglow of a 440 Pa microwave nitrogen discharge operating at 433 MHz in a 3.8 cm diameter tube. The initial conditions in the afterglow are determined by a kinetic model that solves the electron Boltzmann equation coupled to the gas thermal balance equation and a system of rate-balance equations for N2(X 1∑g+, v) molecules, electronically excited states of N2, ground and excited states of atomic nitrogen and the main positive ions. Once the initial concentrations of the heavy species and gas temperature are known, their relaxation in the afterglow is obtained from the solutions to the corresponding time-dependent equations. Modelling predictions are found to be in good agreement with previously measured values for the concentrations of N(4S) atoms and N2(A 3∑u+) molecules, and the radially averaged gas temperature Tg along the afterglow of a microwave discharge in N2 under the same working conditions. It is shown that gas heating in the afterglow comes essentially from the energy transfer involving non-resonant vibration-vibration (V-V) collisions between vibrationally excited nitrogen molecules, as well as from energy exchanges in vibration-translation (V-T) on N2-N collisions. Contribution to the topical issue "Plasma Sources and Plasma Processes (PSPP)", edited by Luis Lemos Alves, Thierry Belmonte and Tiberiu Minea

  17. Soil Gas Sampling Operating Procedure

    EPA Pesticide Factsheets

    EPA Region 4 Science and Ecosystem Support Division (SESD) document that describes general and specific procedures, methods, and considerations when collecting soil gas samples for field screening or laboratory analysis.

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

    SciTech Connect

    Prasetyaningrum, A. Ratnawati,; Jos, B.

    2015-12-29

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

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

    SciTech Connect

    Prasetyaningrum, A., E-mail: ajiprasetyaningrum@gmail.com; Ratnawati,; Jos, B.

    2015-12-29

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

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

    SciTech Connect

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

    2015-12-28

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

  1. Three-dimensional patterns in dielectric barrier discharge with “H” shaped gas gap

    SciTech Connect

    Gao, Xing; Dong, Lifang Wang, Hao; Zhang, Hao; Liu, Ying; Liu, Weibo; Fan, Weili; Pan, Yuyang

    2016-08-15

    Three-dimensional (3D) patterns are obtained for the first time in dielectric barrier discharge by a special designed device with “H” shaped gas gap which consists of a single gas layer gap and two double gas layer gaps. Three dimensional spatiotemporal characteristics of discharge are investigated by photomultiplier and intensified charge-coupled device camera. Results show that the discharge first generates in the single gas layer gap and the coupled filaments in the double gas layer gap present the simultaneity characteristics. The formation of 3D patterns is determined by the distribution of the effective field of the applied field and the wall charge field.

  2. Noble Gas Concept Of Operation

    SciTech Connect

    Carrigan, C. R.

    2014-01-20

    The intent of this document is to provide the reader with an understanding of a general approach to performing the noble gas component of an On Site Inspection or OSI. The authors of this document recognize that owing to the wide range of scenarios that are possible for carrying out an underground nuclear explosion, the diverse sets of information that might be available to the inspection team initially and the potential range of political and physical constraints imposed during the inspection, a satisfactory prescriptive approach to carrying out the noble gas component of an OSI is unlikely. Rather, the authors intend only to aid the reader in understanding what a reasonable course of actions or responses may be as performed by an inspection team (IT) during a general OSI. If this document helps to inform the intuition of the reader about addressing the challenges resulting from the inevitable deviations from this general scenario, it will have achieved its intent.

  3. Zero Discharge Water Management for Horizontal Shale Gas Well Development

    SciTech Connect

    Paul Ziemkiewicz; Jennifer Hause; Raymond Lovett; David Locke Harry Johnson; Doug Patchen

    2012-03-31

    Hydraulic fracturing technology (fracking), coupled with horizontal drilling, has facilitated exploitation of huge natural gas (gas) reserves in the Devonian-age Marcellus Shale Formation (Marcellus) of the Appalachian Basin. The most-efficient technique for stimulating Marcellus gas production involves hydraulic fracturing (injection of a water-based fluid and sand mixture) along a horizontal well bore to create a series of hydraulic fractures in the Marcellus. The hydraulic fractures free the shale-trapped gas, allowing it to flow to the well bore where it is conveyed to pipelines for transport and distribution. The hydraulic fracturing process has two significant effects on the local environment. First, water withdrawals from local sources compete with the water requirements of ecosystems, domestic and recreational users, and/or agricultural and industrial uses. Second, when the injection phase is over, 10 to 30% of the injected water returns to the surface. This water consists of flowback, which occurs between the completion of fracturing and gas production, and produced water, which occurs during gas production. Collectively referred to as returned frac water (RFW), it is highly saline with varying amounts of organic contamination. It can be disposed of, either by injection into an approved underground injection well, or treated to remove contaminants so that the water meets the requirements of either surface release or recycle use. Depending on the characteristics of the RFW and the availability of satisfactory disposal alternatives, disposal can impose serious costs to the operator. In any case, large quantities of water must be transported to and from well locations, contributing to wear and tear on local roadways that were not designed to handle the heavy loads and increased traffic. The search for a way to mitigate the situation and improve the overall efficiency of shale gas production suggested a treatment method that would allow RFW to be used as make

  4. Zero Discharge Water Management for Horizontal Shale Gas Well Development

    SciTech Connect

    Paul Ziemkiewicz; Jennifer Hause; Raymond Lovett

    2012-03-31

    Hydraulic fracturing technology (fracking), coupled with horizontal drilling, has facilitated exploitation of huge natural gas (gas) reserves in the Devonian-age Marcellus Shale Formation (Marcellus) of the Appalachian Basin. The most-efficient technique for stimulating Marcellus gas production involves hydraulic fracturing (injection of a water-based fluid and sand mixture) along a horizontal well bore to create a series of hydraulic fractures in the Marcellus. The hydraulic fractures free the shale-trapped gas, allowing it to flow to the well bore where it is conveyed to pipelines for transport and distribution. The hydraulic fracturing process has two significant effects on the local environment. First,more » water withdrawals from local sources compete with the water requirements of ecosystems, domestic and recreational users, and/or agricultural and industrial uses. Second, when the injection phase is over, 10 to 30% of the injected water returns to the surface. This water consists of flowback, which occurs between the completion of fracturing and gas production, and produced water, which occurs during gas production. Collectively referred to as returned frac water (RFW), it is highly saline with varying amounts of organic contamination. It can be disposed of, either by injection into an approved underground injection well, or treated to remove contaminants so that the water meets the requirements of either surface release or recycle use. Depending on the characteristics of the RFW and the availability of satisfactory disposal alternatives, disposal can impose serious costs to the operator. In any case, large quantities of water must be transported to and from well locations, contributing to wear and tear on local roadways that were not designed to handle the heavy loads and increased traffic. The search for a way to mitigate the situation and improve the overall efficiency of shale gas production suggested a treatment method that would allow RFW to be used

  5. Particle-in-cell modeling of gas-confined barrier discharge

    SciTech Connect

    Levko, Dmitry; Raja, Laxminarayan L.

    2016-04-15

    Gas-confined barrier discharge is studied using the one-dimensional Particle-in-Cell Monte Carlo Collisions model for the conditions reported by Guerra-Garcia and Martinez-Sanchez [Appl. Phys. Lett. 106, 041601 (2015)]. Depending on the applied voltage, two modes of discharge are observed. In the first mode, the discharge develops in the entire interelectrode gap. In the second mode, the discharge is ignited and develops only in the gas layer having smaller breakdown voltage. The one-dimensional model shows that for the conditions considered, there is no streamer stage of breakdown as is typical for a traditional dielectric barrier discharge.

  6. Inception of Snapover and Gas Induced Glow Discharges

    NASA Technical Reports Server (NTRS)

    Galofaro, J. T.; Vayner, B. V.; Degroot, W. A.; Ferguson, D. C.; Thomson, C. D.; Dennison, J. R.; Davies, R. E.

    2000-01-01

    Ground based experiments of the snapover phenomenon were conducted in the large vertical simulation chamber at the Glenn Research Center (GRC) Plasma Interaction Facility (PIF). Two Penning sources provided both argon and xenon plasmas for the experiments. The sources were used to simulate a variety of ionospheric densities pertaining to a spacecraft in a Low Earth Orbital (LEO) environment. Secondary electron emission is believed responsible for dielectric surface charging, and all subsequent snapover phenomena observed. Voltage sweeps of conductor potentials versus collected current were recorded in order to examine the specific charging history of each sample. The average time constant for sample charging was estimated between 25 and 50 seconds for all samples. It appears that current drops off by approximately a factor of 3 over the charging time of the sample. All samples charged in the forward and reverse bias directions, demonstrated hysteresis. Current jumps were only observed in the forward or positive swept voltage direction. There is large dispersion in tile critical snapover potential when repeating sweeps on any one sample. The current ratio for the first snapover region jumps between 2 and 4.6 times, with a standard deviation less than 1.6. Two of the samples showed even larger current ratios. It is believed the second large snapover region is due to sample outgassing. Under certain preset conditions, namely at the higher neutral gas background pressures, a perceptible blue-green glow was observed around the conductor. The glow is believed to be a result of secondary electrons undergoing collisions with an expelled tenuous cloud of gas, that is outgassed from the sample. Spectroscopic measurements of the glow discharge were made in an attempt to identify specific lines contributing to the observed glow.

  7. 46 CFR 153.462 - Static discharges from inert gas systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Static discharges from inert gas systems. 153.462... Equipment Special Requirements for Flammable Or Combustible Cargoes § 153.462 Static discharges from inert... create static arcing as the inert gas is injected into the tank. ...

  8. A high-current rail-type gas switch with preionization by an additional corona discharge

    SciTech Connect

    Antipov, E. I.; Belozerov, O. S.; Krastelev, E. G., E-mail: ekrastelev@yandex.ru

    2016-12-15

    The characteristics of a high-current rail-type gas switch with preionization of the gas (air) in a spark gap by an additional corona discharge are investigated. The experiments were performed in a voltage range of 10–45 kV using a two-electrode switch consisting of two cylindrical electrodes with a diameter of 22 mm and a length of 100 mm and a set of laterally located corona-discharge needles. The requirements for the position and size of the needles are defined for which a corona discharge is ignited before a breakdown of the main gap and does not change to a sparking form, andmore » the entire length of the rail electrodes is efficiently used. The fulfillment of these requirements ensures stable operation of the switch with a small variation of the pulse breakdown voltage, which is not more than 1% for a fixed voltage-pulse rise time in the range from 150 ns to 3.5 μs. A short delay time of the switch breakdown makes it possible to control the two-electrode switch by an overvoltage pulse of nanosecond duration.« less

  9. A high-current rail-type gas switch with preionization by an additional corona discharge

    NASA Astrophysics Data System (ADS)

    Antipov, E. I.; Belozerov, O. S.; Krastelev, E. G.

    2016-12-01

    The characteristics of a high-current rail-type gas switch with preionization of the gas (air) in a spark gap by an additional corona discharge are investigated. The experiments were performed in a voltage range of 10-45 kV using a two-electrode switch consisting of two cylindrical electrodes with a diameter of 22 mm and a length of 100 mm and a set of laterally located corona-discharge needles. The requirements for the position and size of the needles are defined for which a corona discharge is ignited before a breakdown of the main gap and does not change to a sparking form, and the entire length of the rail electrodes is efficiently used. The fulfillment of these requirements ensures stable operation of the switch with a small variation of the pulse breakdown voltage, which is not more than 1% for a fixed voltage-pulse rise time in the range from 150 ns to 3.5 μs. A short delay time of the switch breakdown makes it possible to control the two-electrode switch by an overvoltage pulse of nanosecond duration.

  10. Operating a fuel cell using landfill gas

    SciTech Connect

    Trippel, C.E.; Preston, J.L. Jr.; Trocciola, J.; Spiegel, R.

    1996-12-31

    An ONSI PC25{trademark}, 200 kW (nominal capacity) phosphoric acid fuel cell operating on landfill gas is installed at the Town of Groton Flanders Road landfill in Groton, Connecticut. This joint project by the Connecticut Light & Power Company (CL&P) which is an operating company of Northeast Utilities, the Town of Groton, International Fuel Cells (IFC), and the US EPA is intended to demonstrate the viability of installing, operating and maintaining a fuel cell operating on landfill gas at a landfill site. The goals of the project are to evaluate the fuel cell and gas pretreatment unit operation, test modifications to simplify the GPU design and demonstrate reliability of the entire system.

  11. Operating a fuel cell using landfill gas

    SciTech Connect

    Trippel, C.E.; Preston, J.L. Jr.; Trocciola, J.

    1996-12-31

    An ONSI PC25{trademark}, 200 kW (nominal capacity) phosphoric acid fuel cell operating on landfill gas is installed at the Town of Groton Flanders Road landfill in Groton, Connecticut. This joint project by the Connecticut Light & Power Company (CL&P) which is an operating company of Northeast Utilities, the Town of Groton, International Fuel Cells (IFC), and the US EPA is intended to demonstrate the viability of installing, operating and maintaining a fuel cell operating on landfill gas at a landfill site. The goals of the project are to evaluate the fuel cell and gas pretreatment unit operation, test modifications tomore » simplify the GPU design and demonstrate reliability of the entire system.« less

  12. Routine operative breast endoscopy for bloody nipple discharge.

    PubMed

    Dooley, William C

    2002-11-01

    Submillimeter endoscopes are now available and have been described to assist surgeons in the evaluation and management of symptomatic nipple discharge. To evaluate its potential use, a microendoscope (0.9 mm Acueity) was used on all patients in a single surgeon's practice who were undergoing nipple exploration for spontaneous hemoccult positive nipple discharge. This procedure was performed at the surgical resection of the symptomatic retro-areolar duct, and 27 patients underwent the endoscopy during the period from January 2000 to August 2001. In 96% (26 of 27) of the patients, the endoscope was successfully introduced into the lactiferous sinus, and the proximal breast ducts were successfully visualized. A lesion accounting for the bleeding was seen in all 26 patients, with 70% (n = 19) having multiple intraluminal defects. Cancers were identified in two cases (7.4%), and in both cases, there was a more proximal papilloma in the same ductal system. Similarly, in 33% of the benign cases, both papillomas and usual or atypical ductal hyperplasia were present. Lesions were identified that extended up to 7.5 cm deep to the nipple. The deepest lesion was one of the endoscopically identified cancers in a patient with normal mammogram and breast ultrasound. Surgical resection could be directed by simple transillumination of the skin during endoscopy. This series demonstrates the clinical feasibility of routine operative breast endoscopy in the management of bloody nipple discharge. The high incidence of multiple lesion identification suggests that the classic blind resection of a limited distance of duct in the retroareolar space may significantly underestimate the true extent of proliferative disease accounting for pathologic nipple discharge.

  13. Hydrate Control for Gas Storage Operations

    SciTech Connect

    Jeffrey Savidge

    2008-10-31

    The overall objective of this project was to identify low cost hydrate control options to help mitigate and solve hydrate problems that occur in moderate and high pressure natural gas storage field operations. The study includes data on a number of flow configurations, fluids and control options that are common in natural gas storage field flow lines. The final phase of this work brings together data and experience from the hydrate flow test facility and multiple field and operator sources. It includes a compilation of basic information on operating conditions as well as candidate field separation options. Lastly the work is integrated with the work with the initial work to provide a comprehensive view of gas storage field hydrate control for field operations and storage field personnel.

  14. Modeling Total Dissolved Gas for Optimal Operation of Multireservoir Systems

    SciTech Connect

    Politano, Marcela; Castro, Alejandro; Hadjerioua, Boualem

    2017-02-09

    One important environmental issue of hydropower in the Columbia and Snake River Basins (Pacific Northwest region of United States) is elevated total dissolved gas (TDG) downstream of a dam, which has the potential to cause gas bubble disease in affected fish. Gas supersaturation in the Columbia River Basin primarily occurs due to dissolution of bubbles entrained during spill events. This paper presents a physically based TDG model that can be used to optimize spill operations in multireservoir hydropower systems. Independent variables of the model are forebay TDG, tailwater elevation, spillway and powerhouse discharges, project head, and environmental parameters such as temperature and atmospheric pressure. The model contains seven physically meaningful experimental parameters, which were calibrated and validated against TDG data collected downstream of Rock Island Dam (Washington) from 2008 to 2012. In conclusion, a sensitivity analysis was performed to increase the understanding of the relationships between TDG downstream of the dam and processes such as air entrainment, lateral powerhouse flow, and dissolution.

  15. Harmonic distortion and power factor assessment in city street gas discharge lamps

    SciTech Connect

    Rios, S.; Castaneda, R.; Veas, D.

    1996-04-01

    The current and voltage harmonic spectrum, and power factor in gas discharge lamps: Sodium (Na)-high pressure and Mercury (Hg) in actual use in public street lighting have been measured. A sample of nearby 360 gas discharge lamps (Na, Hg) of different rated power was obtained by simple random sampling over a universe of approximately 15,000 lamps. An equivalent current harmonic spectrum for gas discharge lamps is proposed, which is independent of the type of gas and the lamp rated power. This current spectrum can be used to integrate gas discharge lamp models for harmonic distortion level assessment in distribution networks. The relation of this equivalent current harmonic spectrum with: (1) lamp voltage waveform, (2) type of lamp (Na, Hg), and (3) power factor-capacitor lamp, is analyzed.

  16. Plasma dynamics in a packed bed dielectric barrier discharge (DBD) operated in helium

    NASA Astrophysics Data System (ADS)

    Mujahid, Zaka-ul-Islam; Hala, Ahmed

    2018-03-01

    Packed bed dielectric barrier discharges (DBDs) are very promising for several applications including remediation of environmental pollutants and greenhouse gas conversion. In this work, we have investigated the space and time-resolved emission from a packed bed DBD operated in helium, to understand the plasma dynamics. We have chosen a simple planar DBD arrangement with a patterned dielectric, which mimics the spherical boundaries between the dielectric pellets and allows the optical access to the plasma. The results show that plasma is sustained in a packed bed DBD by three mechanisms: filamentary discharge in the void (between the center of dielectric structures and the opposite electrode), microdischarges at the contact points and surface ionization waves over the dielectric surface. It is observed that for most of the duration plasma is generated at the contact points between the dielectric structures.

  17. Endotoxin removal by radio frequency gas plasma (glow discharge)

    NASA Astrophysics Data System (ADS)

    Poon, Angela

    2011-12-01

    Contaminants remaining on implantable medical devices, even following sterilization, include dangerous fever-causing residues of the outer lipopolysaccharide-rich membranes of Gram-negative bacteria such as the common gut microorganism E. coli. The conventional method for endotoxin removal is by Food & Drug Administration (FDA)-recommended dry-heat depyrogenation at 250°C for at least 45 minutes, an excessively time-consuming high-temperature technique not suitable for low-melting or heat-distortable biomaterials. This investigation evaluated the mechanism by which E. coli endotoxin contamination can be eliminated from surfaces during ambient temperature single 3-minute to cumulative 15-minute exposures to radio-frequency glow discharge (RFGD)-generated residual room air plasmas activated at 0.1-0.2 torr in a 35MHz electrodeless chamber. The main analytical technique for retained pyrogenic bio-activity was the Kinetic Chromogenic Limulus Amebocyte Lysate (LAL) Assay, sufficiently sensitive to document compliance with FDA-required Endotoxin Unit (EU) titers less than 20 EU per medical device by optical detection of enzymatic color development corresponding to < 0.5 EU/ml in sterile water extracts of each device. The main analytical technique for identification of chemical compositions, amounts, and changes during sequential reference Endotoxin additions and subsequent RFGD-treatment removals from infrared (IR)-transparent germanium (Ge) prisms was Multiple Attenuated Internal Reflection (MAIR) infrared spectroscopy sensitive to even monolayer amounts of retained bio-contaminant. KimaxRTM 60 mm x 15 mm and 50mm x 15mm laboratory glass dishes and germanium internal reflection prisms were inoculated with E. coli bacterial endotoxin water suspensions at increments of 0.005, 0.05, 0.5, and 5 EU, and characterized by MAIR-IR spectroscopy of the dried residues on the Ge prisms and LAL Assay of sterile water extracts from both glass and Ge specimens. The Ge prism MAIR

  18. Natural gas in Lake Erie: a reconnaissance survey of discharges from an offshore drilling rig

    SciTech Connect

    Ferrante, J.G.; Dettmann, E.H.; Parker, J.I.

    1980-10-01

    Field studies were conducted May 28-June 1, 1979, to determine the chemical composition and physical behavior of discharges from an offshore gas drilling rig in the central basin of Lake Erie. The drilling operation was observed for four days, from rig jackup to the circulation of mud through the borehole after drilling had been completed. Resuspension studies using nephelometry, supplemented with chemical analyses, indicated little resuspension of lake bottom materials or release of metals to the water column during rig jack-up. Portions of the turbidity plumes generated during drilling were buoyant. Three surface turbidity plumes were mapped with nephelometry to a point at which particulate concentrations reached background levels in the Lake. Detectable plumes were approx. 400 to 1500 m in length and had maximum widths < 230 m. A chemical survey conducted in the plume during early gas shows indicated that discharged inorganic chemical species were rapidly diluted to background concentrations and that methane and ethane concentrations were substantially reduced within 330 m of the rig. There was no evidence of carbon tetrachloride extractable hydrocarbons (CTEH) above background concentrations during this chemical plume survey. However, a pair of water samples taken within 100 m of the rig approximately 3 hours after drilling of the target zone was completed had CTEH concentrations that were a factor of 2.4 above background.

  19. Interelectrode bridging of carbon nanotube fibrous assembly induced by gas discharge breakdown

    NASA Astrophysics Data System (ADS)

    Sato, Hideki; Mizushima, Yuuki; Komatsu, Yusuke

    2017-01-01

    In this work, we demonstrate a fibrous assembly of carbon nanotubes (CNTs) induced by a gas discharge breakdown that bridge the distance between two planar electrodes. To achieve this, we placed the two planar electrodes, one of which was covered with a CNT film, in a chamber; a vacuum pump was used to evacuate the air from the chamber and replace it with inert gas. By then applying a voltage between the electrodes, we induced a discharge breakdown between them. This caused the CNTs coated on the electrode surface to detach and form fibrous assemblies. The assemblies elongated and reached the opposite electrode, thereby creating bridges between the electrodes. These bridges formed when the gas pressure was greater than ca. 1.0 × 103 Pa and in combination with the occurrence of a spark discharge. At lower pressures, a glow discharge occurred, and no bridge formation was observed, indicating that the discharge mode is critical for the bridge formation.

  20. Binary and ternary gas mixtures for use in glow discharge closing switches

    DOEpatents

    Hunter, Scott R.; Christophorou, Loucas G.

    1990-01-01

    Highly efficient binary and ternary gas mixtures for use in diffuse glow discharge closing switches are disclosed. The binary mixtures are combinations of helium or neon and selected perfluorides. The ternary mixtures are combinations of helium, neon, or argon, a selected perfluoride, and a small amount of gas that exhibits enhanced ionization characteristics. These mixtures are shown to be the optimum choices for use in diffuse glow discharge closing switches by virtue of the combined physio-electric properties of the mixture components.

  1. Quasi-stationary convection in a periodic-pulsed optical discharge in high pressure rare gas

    NASA Astrophysics Data System (ADS)

    Zimakov, V. P.; Kuznetsov, V. A.; Solovyov, N. G.; Shemyakin, A. N.; Shilov, A. O.; Yakimov, M. Yu

    2017-02-01

    Unusual convection flows were observed in stabilized pre-breakdown phase of the periodic-pulsed optical discharge (POD) called “quiet” POD. The discharge was a relatively weakly glowing plasma filament sustained by focused λ = 1.064 μm laser pulses with repetition rate of fr = 50÷100 kHz at the intensity several times below than that required for the optical breakdown to occur. No strong shock waves or irregular turbulence around the discharge were observed, in contrast to breakdown types of POD. Significant laser beam refraction measured in the beam cross-section behind the discharge zone was explained by the gas heating in the discharge up to 10 kK, providing high gradients of gas density and refraction index. Intense convective flow was detected on the schlieren images as thermal traces of the laser-induced gas streams flowing from the discharge zone, directed mainly normally to the optical axis. Repeated relaxation of the gas expanding after being rapidly heated by the laser pulse is proposed to explain the effect. The periodic-pulsed discharge located in the elongated beam waist generates an anisotropic heated region with gas streams and vortices, which may form the observed regular convective flow at the late stages of expanding.

  2. Initiation of long, free-standing z discharges by CO2 laser gas heating

    NASA Astrophysics Data System (ADS)

    Niemann, C.; Tauschwitz, A.; Penache, D.; Neff, S.; Knobloch, R.; Birkner, R.; Presura, R.; Hoffmann, D. H. H.; Yu, S. S.; Sharp, W. M.

    2002-01-01

    High current discharge channels can neutralize both current and space charge of very intense ion beams. Therefore, they are considered an interesting solution for final focus and beam transport in a heavy ion beam fusion reactor. At the Gesellschaft für Schwerionenforschung accelerator facility, 50 cm long, free-standing discharge channels were created in a 60 cm diameter metallic chamber. Discharges with currents of 45 kA in 2 to 25 mbar ammonia (NH3) gas are initiated by a CO2 laser pulse along the channel axis before the capacitor bank is triggered. Resonant absorption of the laser, tuned to the v2 vibration of the ammonia molecule, causes strong gas heating. Subsequent expansion and rarefaction of the gas prepare the conditions for a stable discharge to fulfill the requirements for ion beam transport. The influence of an electric prepulse on the high current discharge was investigated. This article describes the laser-gas interaction and the discharge initiation mechanism. We found that channels are magnetohydrodynamic stable up to currents of 45 kA, measured by fast shutter and streak imaging techniques. The rarefaction of the laser heated gas is studied by means of a one-dimensional Lagrangian fluid code (CYCLOPS) and is identified as the dominant initiation mechanism of the discharge.

  3. Production of Ar and Xe metastables in rare gas mixtures in a dielectric barrier discharge

    NASA Astrophysics Data System (ADS)

    Mikheyev, Pavel A.; Han, Jiande; Clark, Amanda; Sanderson, Carl; Heaven, Michael C.

    2017-12-01

    Optically pumped all-rare-gas lasers (OPRGL) utilize metastable atoms of the heavier rare gases as lasing species. The required number density of metastables for efficient laser operation is 1012–1013 cm‑3 in He buffer gas at pressures in the 400–1000 Torr range. Such metastable densities are easily produced in a nanosecond pulsed discharge, even at pressures larger than atmospheric, but problems appear when one is trying to achieve continuous production. The reason for low production efficiency in many types of continuous discharge at atmospheric pressure is the low value of the E/N parameter (<5–6 Td). In the present work, we have examined the possibility of using a dielectric barrier discharge (DBD) to provide near continuous, high densities of Ar and Xe metastables. Experiments were performed using a 20 kHz DBD in binary Ar and Xe mixtures with He, and in ternary Ar:Xe:He mixtures at pressures up to 1 atmosphere. Concentrations were measured by means of tunable diode laser absorption spectroscopy. Time-averaged [Ar(1s5)] and [Xe(1s5)] number densities on the order of 1012 cm‑3 were readily achieved. The temporal behavior of [Xe(1s5)] throughout the DBD cycle was observed. The results demonstrate the feasibility of using DBDs for OPRGL development. Spectral scans over the absorption lines were also used to examine the pressure broadening coefficients for the 912.3 nm Ar line in He and the Xe 904.5 nm line in Ne and He.

  4. Three-dimensional patterns in dielectric barrier discharge with “H” shaped gas gap

    SciTech Connect

    Gao, Xing; Dong, Lifang, E-mail: donglfhbu@163.com; Wang, Hao

    2016-08-15

    Three-dimensional (3D) patterns are obtained for the first time in dielectric barrier discharge by a special designed device with “H” shaped gas gap which consists of a single gas layer gap and two double gas layer gaps. Three dimensional spatiotemporal characteristics of discharge are investigated by photomultiplier and intensified charge-coupled device camera. Results show that the discharge first generates in the single gas layer gap and the coupled filaments in the double gas layer gap present the simultaneity characteristics. The formation of 3D patterns is determined by the distribution of the effective field of the applied field and the wallmore » charge field.« less

  5. Dimmable Electronic Ballast for a Gas Discharge Lamp

    NASA Technical Reports Server (NTRS)

    Raducanu, Marius; Hennings, Brian D.

    2013-01-01

    Titanium dioxide (TiO2) is the most efficient photocatalyst for organic oxidative degradation. TiO2 is effective not only in aqueous solution, but also in nonaqueous solvents and in the gas phase. It is photostable, biologically and chemically inert, and non-toxic. Low-energy UV light (approximately 375 nm, UV-A) can be used to photoactivate TiO2. TiO2 photocatalysis has been used to mineralize most types of organic compounds. Also, TiO2 photocatalysis has been effectively used in sterilization. This effectiveness has been demonstrated by its aggressive destruction of microorganisms, and aggressive oxidation effects of toxins. It also has been used for the oxidation of carbon monoxide to carbon dioxide, and ammonia to nitrogen. Despite having many attractive features, advanced photocatalytic oxidation processes have not been effectively used for air cleaning. One of the limitations of the traditional photocatalytic systems is the ballast that powers (lights) the bulbs. Almost all commercial off-the-shelf (COTS) ballasts are not dimmable and do not contain safety features. COTS ballasts light the UV lamp as bright as the bulb can be lit, and this results in shorter bulb lifetime and maximal power consumption. COTS magnetic ballasts are bulky, heavy, and inefficient. Several iterations of dimmable electronic ballasts have been developed. Some manifestations have safety features such as broken-bulb or over-temperature warnings, replace-bulb alert, logbulb operational hours, etc. Several electronic ballast boards capable of independently lighting and controlling (dimming) four fluorescent (UV light) bulbs were designed, fabricated, and tested. Because of the variation in the market bulb parameters, the ballast boards were designed with a very broad range output. The ballast boards can measure and control the current (power) for each channel.

  6. Transformations of dust structures in glow DC discharge in neon: effect of gas temperature and discharge current

    NASA Astrophysics Data System (ADS)

    Polyakov, D. N.; Shumova, V. V.; Vasilyak, L. M.

    2017-08-01

    The dependence of the shape of the dust structures on discharge current and pressure in neon glow DC discharge at temperatures 77 K and 295 К has been studied experimentally. It was found that when the discharge current was increased, the radial size of the dust cloud increased, and the axial size decreased. It was found that at 295 К the dust clouds were formed by individual dust particles, while at 77 K they consisted of a mixture of dust particles and simplest threadlike clusters formed from dust particles. The decrease of gas pressure led to increase in distances between the dust particles and clusters, and reduced the dynamic stability of the dust particles and clusters. At 295 К an increase of the discharge current resulted in the formation of voids in dust structures, while at 77 K the formation of the dust structures with voids was not observed even at maximum discharge currents. The formation of clusters at cryogenic cooling can be interpreted as ‘condensation’ and ‘deposition’ of dust particles.

  7. Decomposition of phenol by hybrid gas/liquid electrical discharge reactors with zeolite catalysts.

    PubMed

    Kusić, Hrvoje; Koprivanac, Natalija; Locke, Bruce R

    2005-10-17

    Application of hybrid gas/liquid electrical discharge reactors and a liquid phase direct electrical discharge reactor for degradation of phenol in the presence and absence of zeolites have been investigated. Hybrid gas/liquid electrical discharges involve simultaneous high voltage electrical discharges in water and in the gas phase above the water surface leading to the additional OH radicals in the liquid phase and ozone formation in the gas phase with subsequent dissolution into the liquid. The role of applied zeolites, namely NH4ZSM5, FeZSM5 and HY, were also studied. Phenol degradation and production of primary phenol by-products, catechol and hydroquinone, during the treatment were monitored by HPLC measurements. The highest phenol removal results, 89.4-93.6%, were achieved by electrical discharge in combination with FeZSM5 in all three configurations of corona reactors. These results indicate that the Fenton reaction has significant influence on overall phenol removal efficiency in the electrical discharge/FeZSM5 system due to the additional OH radical formation from hydrogen peroxide generated by the water phase discharge.

  8. Initiation of long, free-standing Z-discharges by CO2 laser gas heating

    SciTech Connect

    Nieman, C.; Tauschwitz, A.; Penache, D.; Neff, S.; Knobloch, R.; Birkner, R.; Presura, R.; Hoffmann, D.H.H.; Yu, S.S.; Sharp, W.M.

    2004-04-19

    High current discharge channels can neutralize both current and space charge of very intense ion beams. Therefore they are considered as an interesting alternative for the final focus and beam transport in a heavy ion beam fusion reactor. At the GSI accelerator facility, 50 cm long, stable, free-standing discharge channels with currents in excess of 40 kA in 2 to 25 mbar ammonia (NH{sub 3}) gas are investigated for heavy ion beam transport studies. The discharges are initiated by a CO{sub 2} laser pulse along the channel axis before the discharge is triggered. Resonant absorption of the laser, tuned to the {nu}{sub 2} vibration of the ammonia molecule, causes strong gas heating. Subsequent expansion and rarefaction of the gas prepare the conditions for a stable discharge to fulfill the requirements for ion beam transport. This paper describes the laser-gas interaction and the discharge initiation mechanism. We report on the channel stability and evolution, measured by fast shutter and streak imaging techniques. The rarefaction of the laser heated gas is studied by means of a hydrocode simulation.

  9. Gas evolution study of Ca/CaCrO4 thermal batteries during discharge

    NASA Astrophysics Data System (ADS)

    Burns, F. B.; Guidotti, R. A.; Reinhardt, F. W.; Rodacy, P. J.

    The gases which are generated upon activation and during discharge of Ca/CaCrO4 thermal batteries are of interest, as they can provide insight into the reactions which are occurring. This, in turn, can result in an increased understanding of the discharge mechanism. Mass spectrometry (MS) was employed in limited studies to examine the overgas composition of discharge Ca/CaCrO4 thermal batteries. No data have been reported, however, for the gas composition throughout the activated life of such batteries. The study was undertaken to obtain gas-composition profiles on a real time basis during the discharge of Ca/CaCrO4 thermal batteries and to identify, if possible, the relative contributions made by the various battery components. The gas evolution information was then evaluated for possible correlation to the observed electrochemical performance. Results are presented and discussed.

  10. Prebreakdown phenomena and formation process of the glow discharge in low-pressure Ar gas

    SciTech Connect

    Hosokawa, Tatsuzo; Goto, Kazuhiro; Ohuchi, Mikio

    2001-06-01

    The prebreakdown phenomena and the formation process of the glow discharge in a low-pressure Ar gas were investigated under a uniform field gap. Prebreakdown phenomena were observed for 0.5Torrcm{le}pd{le}2Torrcm (where p is pressure, d the gap distance) in Ar gas under conditions of a slowly increasing voltage. It was observed that the prebreakdown phenomena formed pulse discharges up to the transition to the glow discharge. The amplitudes of the photon and current pulses due to the pulse discharge increased with time, and then decreased as soon as the transition to a steady glow discharge occurred. When the overvoltage or externalmore » series resistance was increased, the pulse amplitudes increased with the applied voltage and decreased with the resistance. The characteristics of the prebreakdown phenomena were changed by the shape of the electrodes. The formation mechanism of the glow discharge can be qualitatively explained by that of the streamer in a high-pressure discharge. The transient glow discharge was observed, and its duration increased with an increase in resistance. The instability of the glow discharge was controlled by three factors, namely, Kaufmann{close_quote}s criterion, the Child{endash}Langmuir law, and the density balance between the production and removal rates of electrons. {copyright} 2001 American Institute of Physics.« less

  11. Numerical investigation on operation mode influenced by external frequency in atmospheric pressure barrier discharge

    SciTech Connect

    Wang Qi; Sun Jizhong; Wang Dezhen

    2011-10-15

    The influence of external driving frequency on the discharge mode in the dielectric barrier discharge was investigated with a two-dimensional, self-consistent fluid model. The simulation results show that the helium discharge exhibits three operation modes: Townsend, homogeneous glow, and local glow discharges from the lower frequency (1 kHz) to the higher frequency (100 kHz) under discharge parameters specified in this work. The discharge operates in a Townsend mode when the driving frequency varies from 1 to about 7 kHz; while it exhibits homogenous glow characteristics in an approximate range from 7 to 65 kHz; when the external frequency exceeds 65 kHz, it turns into a local glow discharge. The effects of external driving frequency on the discharge mode were revealed and the physical reasons were discussed.

  12. The gas discharge dusty plasma in a uniform magnetic field

    NASA Astrophysics Data System (ADS)

    Abdirakhmanov, A. R.; Dosbolayev, M. K.; Ramazanov, T. S.

    2018-01-01

    At present, there are several theoretical assumptions that the rotation of the plasma-dust structures in the striation in a magnetic field can be caused by the presence of a number of irregularities. In this paper one of the irregularities, such as the influence of the edge effect at the ends of the solenoids on the rotational motion of plasma-dust structures in the stratum of the glow discharge, was experimentally investigated.

  13. Longitudinal Plasmoid in High-Speed Vortex Gas Flow Created by Capacity HF Discharge

    DTIC Science & Technology

    2010-10-28

    and destruction of vortex by weakly ionized non-equilibrium HF plasma. 3. Measurement of vortex plasmoid’s parameters and vortex gas flow parameters...in non-equilibrium longitudinal plasmoid created capacity HF discharge in high-speed vortex gas flow . Study of their roles in plasma vortex structure ...vortex gas flow . Study of their roles in plasma vortex structure and its dynamics. 2. Study of the stable plasmoid creation regimes in high-speed

  14. Discharge stabilization studies of CO laser gas mixtures in quasi-steady supersonic flow

    NASA Technical Reports Server (NTRS)

    Srinivasan, G.; Smith, J. A.

    1976-01-01

    Experiments were conducted to study the applicability of a double discharge stabilization scheme in conditions appropriate for high energy CO lasers in supersonic flows. A Ludwieg tube impulse flow facility and a ballasted capacitor bank provided essentially steady flow and discharge conditions (d.c.) for times longer than ten electrode length-flow transit times. Steady, arc-free, volume discharges were produced in a Mach 3 test cavity using an auxiliary discharge to stabilize the main discharge in N2 and He/CO mixture. A signigicant result is the lack of observed plasma E/N changes in response to auxiliary discharge current changes. Also, where glow discharges were obtained, the energy loading achieved was very much less than the threshold level required for laser operation.

  15. Investigation of Ultraviolet Photoionization Sustained Discharge for Gas Lasers

    DTIC Science & Technology

    1974-08-01

    were undertaken next using a device with a larger discharge volume (2.5 x 15 x 50 cm3) and an improved uv source configuration. Output energies in...active volume, 115 joules have been extracted from the device in initial measurements which corresponds to an energy density of 27 J/l- atm...TMIS OkOT’Whrn Pil* fnirtr ^m—m -’"’-- ’■"■■," ’"-"^li HIHI »!»■■■ i n -.,...,--,•.- TABLE OF CONTENTS LIST OF ILLUSTRATIONS v ABSTRACT vii

  16. Noise characterization of oil and gas operations.

    PubMed

    Radtke, Cameron; Autenrieth, Daniel A; Lipsey, Tiffany; Brazile, William J

    2017-08-01

    In cooperation with The Colorado Oil and Gas Conservation Commission, researchers at Colorado State University performed area noise monitoring at 23 oil and gas sites throughout Northern Colorado. The goals of this study were to: (1) measure and compare the noise levels for the different phases of oil and gas development sites; (2) evaluate the effectiveness of noise barriers; and (3) determine if noise levels exceeded the Colorado Oil and Gas Conservation Commission noise limits. The four phases of oil and gas development include drilling, hydraulic fracturing, completion and production. Noise measurements were collected using the A- and C-weighted sound scales. Octave band analysis was also performed to characterize the frequency spectra of the noise measurements.  Noise measurements were collected using noise dosimeters and a hand-held sound-level meter at specified distances from the development sites in each cardinal direction. At 350 ft (107 m), drilling, hydraulic fracturing, and completion sites without noise barriers exceeded the maximum permissible noise levels for residential and commercial zones (55 dBA and 60 dBA, respectively). In addition, drilling and hydraulic fracturing sites with noise barriers exceeded the maximum permissible noise level for residential zones (55 dBA). However, during drilling, hydraulic fracturing, and completion operations, oil producers are allowed an exception to the noise permissible limits in that they only must comply with the industrial noise limit (80 dBA). It is stated in Rule 604.c.(2)A. that: "Operations involving pipeline or gas facility installation or maintenance, the use of a drilling rig, completion rig, workover rig, or stimulation is subject to the maximum permissible noise levels for industrial zones (80dBA)." [8] Production sites were within the Colorado Oil and Gas Conservation Commission permissible noise level criteria for all zones. At 350 ft (107 m) from the noise source, all drilling

  17. 33 CFR 151.79 - Operating requirements: Discharge of sewage within Antarctica.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Operating requirements: Discharge of sewage within Antarctica. 151.79 Section 151.79 Navigation and Navigable Waters COAST GUARD... Pollution and Sewage § 151.79 Operating requirements: Discharge of sewage within Antarctica. (a) A vessel...

  18. 33 CFR 151.79 - Operating requirements: Discharge of sewage within Antarctica.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Operating requirements: Discharge of sewage within Antarctica. 151.79 Section 151.79 Navigation and Navigable Waters COAST GUARD... Pollution and Sewage § 151.79 Operating requirements: Discharge of sewage within Antarctica. (a) A vessel...

  19. Effect of duty-cycles on the air plasma gas-phase of dielectric barrier discharges

    NASA Astrophysics Data System (ADS)

    Barni, R.; Biganzoli, I.; Dell'Orto, E. C.; Riccardi, C.

    2015-10-01

    An experimental investigation concerning the effects of a duty-cycle in the supply of a dielectric barrier discharge in atmospheric pressure air has been performed. Electrical characteristics of the discharge have been measured, focusing mainly on the statistical properties of the current filaments and on dielectric surface charging, both affected by the frequent repetition of breakdown imposed by the duty-cycle. Information on the gas-phase composition was gathered too. In particular, a strong enhancement in the ozone formation rate is observed when suitable long pauses separate the active discharge phases. A simulation of the chemical kinetics in the gas-phase, based on a simplified discharge modeling, is briefly described in order to shed light on the observed increase in ozone production. The effect of a duty-cycle on surface modification of polymeric films in order to increase their wettability has been investigated too.

  20. Equilibrium gas pressure in various operating modes of ion-plasma accelerators

    NASA Astrophysics Data System (ADS)

    Korolev, C. V.; Movsesyants, Yu B.; Tyuryukanov, P. M.

    2017-07-01

    The results of measurements gas equilibrium pressure and elemental composition for various operating modes of two-stage ion-plasma accelerators using a discharge in a transverse strongly inhomogeneous magnetic field are presented. It is established that the gas pressure in the chamber is most strongly changed at small ion currents to the collector. The main process of gas separation is the desorption from the surface of the electrodes under the action of low-energy ions. In steady state, with an accelerating voltage more than 1 kV, the gas pressure changes slightly. The main process is spraying.

  1. Potential Industrial Applications of the One Atmosphere Uniform Glow Discharge Plasma (OAUGDP) Operating in Ambient Air

    NASA Astrophysics Data System (ADS)

    Reece Roth, J.

    2004-11-01

    The majority of industrial plasma processing with glow discharges has been conducted at pressures below 10 torr. This tends to limit applications to high value workpieces as a result of the high capital cost of vacuum systems and the production constraints of batch processing. It has long been recognized that glow discharge plasmas would play a much larger industrial role if they could be generated at one atmosphere. The One Atmosphere Uniform Glow Discharge Plasma (OAUGDP), developed at the University of Tennessee's Plasma Sciences Laboratory, is a non-thermal RF plasma operating on displacement currents with the time-resolved characteristics of a classical low pressure DC normal glow discharge. As a glow discharge, the OAUGDP operates with maximum electrical efficiency at the Stoletow point, where the energy input per ion-electron pair is a minimum [1, 2]. Several interdisciplinary teams have investigated potential applications of the OAUGDP. These teams included collaborators from the UTK Textiles and Nonwovens Development Center (TANDEC), and the Departments of Electrical and Computer Engineering, Microbiology, and Food Science and Technology, as well as the NASA Langley Research Center. The potential applications of the OAUGDP have all been at one atmosphere and room temperature, using air as the working gas. These applications include sterilizing medical and dental equipment; sterilizable air filters to deal with the "sick building syndrome"; removal of soot from Diesel engine exhaust; subsonic plasma aerodynamic effects, including flow re-attachment to airfoils and boundary layer modification; electrohydrodynamic (EDH) flow control of working gases; increasing the surface energy of materials; improving the adhesion of paints and electroplated layers: improving the wettability and wickability of fabrics; stripping of photoresist; and plasma deposition and directional etching of potential microelectronic relevance. [1] J. R. Roth, Industrial Plasma Engineering

  2. Effects of Gas Flow Rate on the Discharge Characteristics of a DC Excited Plasma Jet

    NASA Astrophysics Data System (ADS)

    Li, Xuechen; Jia, Pengying; Di, Cong; Bao, Wenting; Zhang, Chunyan

    2015-09-01

    A direct current (DC) source excited plasma jet consisting of a hollow needle anode and a plate cathode has been developed to form a diffuse discharge plume in ambient air with flowing argon as the working gas. Using optical and electrical methods, the discharge characteristics are investigated for the diffuse plasma plume. Results indicate that the discharge has a pulse characteristic, under the excitation of a DC voltage. The discharge pulse corresponds to the propagation process of a plasma bullet travelling from the anode to the cathode. It is found that, with an increment of the gas flow rate, both the discharge plume length and the current peak value of the pulsed discharge decrease in the laminar flow mode, reach their minima at about 1.5 L/min, and then slightly increase in the turbulent mode. However, the frequency of the pulsed discharge increases in the laminar mode with increasing the argon flow rate until the argon flow rate equals to about 1.5 L/min, and then slightly decreases in the turbulent mode. supported by National Natural Science Foundation of China (Nos. 10805013, 11375051), Funds for Distinguished Young Scientists of Hebei Province, China (No. A2012201045), Department of Education for Outstanding Youth Project of China (No. Y2011120), and Youth Project of Hebei University of China (No. 2011Q14)

  3. Binary and ternary gas mixtures for use in glow discharge closing switches

    DOEpatents

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

    1988-04-27

    Highly efficient binary and ternary gas mixtures for use in diffuse glow discharge closing switches are disclosed. The binary mixtures are combinations of helium or neon and selected perfluorides. The ternary mixtures are combinations of helium, neon, or argon, a selected perfluoride, and a small amount of gas that exhibits enhanced ionization characteristics. These mixtures are shown to be the optimum choices for use in diffuse glow discharge closing switches by virtue if the combines physio-electric properties of the mixture components. 9 figs.

  4. Emission Spectroscopy of the 4X Source Discharge With and Without N2 Gas

    SciTech Connect

    Smith, Horace Vernon

    2016-01-14

    This tech note summarizes the December, 1988 emission spectroscopy measurements made on the 4X source discharge with and without N₂ gas added to the H + Cs discharge. This study is motivated by the desire to understand why small amounts of N₂ gas added to the source discharge results in a reduction in the H⁻ beam noise. The beneficial effect of N₂ gas on H⁻ beam noise was first discovered by Bill Ingalls and Stu Orbesen on the ATS SAS source. For the 4X source the observed effect is that when N2 gas is added to the discharge the H⁻ beam noise is reduced about a factor of 2.

  5. Modeling Total Dissolved Gas for Optimal Operation of Multireservoir Systems

    DOE PAGES

    Politano, Marcela; Castro, Alejandro; Hadjerioua, Boualem

    2017-02-09

    One important environmental issue of hydropower in the Columbia and Snake River Basins (Pacific Northwest region of United States) is elevated total dissolved gas (TDG) downstream of a dam, which has the potential to cause gas bubble disease in affected fish. Gas supersaturation in the Columbia River Basin primarily occurs due to dissolution of bubbles entrained during spill events. This paper presents a physically based TDG model that can be used to optimize spill operations in multireservoir hydropower systems. Independent variables of the model are forebay TDG, tailwater elevation, spillway and powerhouse discharges, project head, and environmental parameters such asmore » temperature and atmospheric pressure. The model contains seven physically meaningful experimental parameters, which were calibrated and validated against TDG data collected downstream of Rock Island Dam (Washington) from 2008 to 2012. In conclusion, a sensitivity analysis was performed to increase the understanding of the relationships between TDG downstream of the dam and processes such as air entrainment, lateral powerhouse flow, and dissolution.« less

  6. Discharge characteristics and hydrodynamics behaviors of atmospheric plasma jets produced in various gas flow patterns

    NASA Astrophysics Data System (ADS)

    Setsuhara, Yuichi; Uchida, Giichiro; Nakajima, Atsushi; Takenaka, Kosuke; Koga, Kazunori; Shiratani, Masaharu

    2015-09-01

    Atmospheric nonequilibrium plasma jets have been widely employed in biomedical applications. For biomedical applications, it is an important issue to understand the complicated mechanism of interaction of the plasma jet with liquid. In this study, we present analysis of the discharge characteristics of a plasma jet impinging onto the liquid surface under various gas flow patterns such as laminar and turbulence flows. For this purpose, we analyzed gas flow patters by using a Schlieren gas-flow imaging system in detail The plasma jet impinging into the liquid surface expands along the liquid surface. The diameter of the expanded plasma increases with gas flow rate, which is well explained by an increase in the diameter of the laminar gas-flow channel. When the gas flow rate is further increased, the gas flow mode transits from laminar to turbulence in the gas flow channel, which leads to the shortening of the plasm-jet length. Our experiment demonstrated that the gas flow patterns strongly affect the discharge characteristics in the plasma-jet system. This study was partly supported by a Grant-in-Aid for Scientific Research on Innovative Areas ``Plasma Medical Innovation'' (24108003) from the Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT).

  7. Effect of voltage amplitude on gas density variation in an atmospheric pressure streamer discharge

    NASA Astrophysics Data System (ADS)

    Komuro, Atsushi; Ando, Akira

    2017-05-01

    Gas density variation in an atmospheric-pressure streamer discharge was visualized using the Schlieren method and was simulated by a two-dimensional axisymmetric simulation. The Schlieren images visualized the occurrence of shock waves and decrease in the gas density after the discharge. The axial distribution of the gas density was compared between experimental and simulation models, and we found that the two were in good agreement. Additionally, this paper discusses the effect of the pulse voltage amplitude on the decrease in the gas density. Our simulation results show that the pulse voltage amplitude affects the ratio of energy loss fractions of electrons by electron-impact collision processes. Contribution to the topical issue "The 15th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XV)", edited by Nicolas Gherardi and Tomášs Hoder

  8. Real gas effects on charging and discharging processes of high pressure pneumatics

    NASA Astrophysics Data System (ADS)

    Luo, Yuxi; Wang, Xuanyin; Ge, Yaozheng

    2013-01-01

    The high pressure pneumatic system has been applied to special industries. It may cause errors when we analyze high pressure pneumatics under ideal gas assumption. However, the real gas effect on the performances of high pressure pneumatics is seldom investigated. In this paper, the real gas effects on air enthalpy and internal energy are estimated firstly to study the real gas effect on the energy conversion. Under ideal gas assumption, enthalpy and internal energy are solely related to air temperature. The estimation result indicates that the pressure enthalpy and pressure internal energy of real pneumatic air obviously decrease the values of enthalpy and internal energy for high pressure pneumatics, and the values of pressure enthalpy and pressure internal energy are close. Based on the relationship among pressure, enthalpy and internal energy, the real gas effects on charging and discharging processes of high pressure pneumatics are estimated, which indicates that the real gas effect accelerates the temperature and pressure decreasing rates during discharging process, and decelerates their increasing rates during charging process. According to the above analysis, and for the inconvenience in building the simulation model for real gas and the difficulty of measuring the detail thermal capacities of pneumatics, a method to compensate the real gas effect under ideal gas assumption is proposed by modulating the thermal capacity of the pneumatic container in simulation. The experiments of switching expansion reduction (SER) for high pressure pneumatics are used to verify this compensating method. SER includes the discharging process of supply tanks and the charging process of expansion tank. The simulated and experimental results of SER are highly consistent. The proposed compensation method provides a convenient way to obtain more realistic simulation results for high pressure pneumatics.

  9. Waveguide CO2 laser gain: Dependence on gas kinetic and discharge properties

    NASA Technical Reports Server (NTRS)

    Cohen, S. C.

    1975-01-01

    Using a simple rate equation approach the gas kinetic and discharge properties of waveguide CO2 lasers were examined. The dependence was calculated of the population inversion and laser small signal gain on gas pressure, gas mixture, pumping rate (discharge current), tube bore diameter, and wall temperature. At higher pressures the gain is optimized by using more helium rich mixtures and smaller bore diameters. The dependence of laser tunability on the gas kinetic properties and cavity losses was determined, it was found that for loss cavities the laser tunability may substantially exceed the molecular fullwidth at half maximum. The more helium rich gas mixtures give greater tunability when cavity losses are small and less tunability when cavity losses are large. The role of the various gases in the waveguide CO2 laser is the same as that in conventional devices, by contrast with conventional lasers, the waveguide laser transition is homogeneously broadened. The dependence of gain on gas pressure and other kinetic and discharge properties differs substantially from that predicted by scaling results from conventional low pressure lasers.

  10. Gas discharges in fumarolic ice caves of Erebus volcano, Antarctica

    NASA Astrophysics Data System (ADS)

    Fischer, T. P.; Curtis, A. G.; Kyle, P. R.; Sano, Y.

    2013-12-01

    Fumarolic ice caves and towers on Erebus are the surface expression of flank degassing on the world's southernmost active volcano. The caves are formed by warm gases and steam escaping from small vents on the lava flow floors that melts the overlying ice and snow. Extremophiles in the caves may be analogues for extraterrestrial environments. Over the past four Austral summers, mapping, gas and thermal monitoring conducted under the Erebus Caves Project has provided insights into the ice cave formation processes and the relationships between cave structures, magmatic processes, and weather. Gas samples were collected during the 2012 - 2013 field season in 4 ice caves (Warren, Harry's Dream, Sauna, Haggis Hole) as well as the thermal ground at Tramway Ridge. The vents at all of these sites are characterized by diffuse degassing through loose lava or cracks in the lava flow floor. Vent temperatures ranged from 5 to 17°C in most caves and at Tramway Ridge. In Sauna cave the temperature was 40°C. Gases were sampled by inserting a perforated 1 m long, 5 mm diameter stainless steel tube, into the vents or hot ground. Giggenbach bottles, copper tubes and lead glass bottles were connected in series. The gases were pumped at a slow rate (about 20 ml per minute) using a battery pump for 12-24 hours to flush the system. After flushing samples were collected for later analyses. All samples are dominated by atmospheric components, however, carbon dioxide (0.1 to 1.9%), methane (0.005 to 0.01%), hydrogen (0.002 to 0.07%), and helium (0.0009 to 0.002 %) are above air background. Nitrogen (average 74%) and oxygen (23.5%) are slightly below and above air values, respectively. Helium isotopes show minor input of mantle derived helium-3 with 3He4He ratios ranging from 1.03 to 1.18 RA (where RA is the ratio of air). This represents the first detection of hydrogen and helium in the caves. Methane could be produced by anaerobic respiration of subsurface microbes or hydrothermal

  11. Observed river discharge changes due to hydropower operations in the Upper Mekong Basin

    NASA Astrophysics Data System (ADS)

    Räsänen, Timo A.; Someth, Paradis; Lauri, Hannu; Koponen, Jorma; Sarkkula, Juha; Kummu, Matti

    2017-02-01

    The Upper Mekong Basin is undergoing extensive hydropower development and its largest dams have recently become operational. Hydropower is built to improve the regional energy supply, but at the same time, it has considerable transboundary impacts on downstream discharge regime and further on aquatic ecosystems, riparian livelihoods and food security. Despite the transboundary significance of the impacts, there is no public information on the hydropower operations or on the already observed downstream discharge impacts since the completion of the largest dams. Therefore, in this study we assess the discharge changes using observed river discharge data and a distributed hydrological model over the period of 1960-2014. Our findings indicate that the hydropower operations have considerably modified the river discharges since 2011 and the largest changes were observed in 2014. According to observed and simulated discharges, the most notable changes occurred in northern Thailand (Chiang Saen) in March-May 2014 when the discharge increased by 121-187% and in July-August 2014 when the discharge decreased by 32-46% compared to average discharges. The respective changes in Cambodia (Kratie) were 41-74% increase in March-May 2014 and 0-6% decrease in July-August 2014 discharges. The earlier model-based predictions of the discharge changes are well in line with the observed changes, although observed changes are partly larger. The discharge impacts are expected to vary from year to year depending on hydropower operations. Altogether, the results highlight the need for strong transboundary cooperation for managing the downstream impacts.

  12. Infrared gas phase study on plasma-polymer interactions in high-current diffuse dielectric barrier discharge

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Welzel, S.; Starostin, S. A.; van de Sanden, M. C. M.; Engeln, R.; de Vries, H. W.

    2017-06-01

    A roll-to-roll high-current diffuse dielectric barrier discharge at atmospheric pressure was operated in air and Ar/N2/O2 gas mixtures. The exhaust gas from the discharge was studied using a high-resolution Fourier-transform infrared spectrometer in the range from 3000 to 750 cm-1 to unravel the plasma-polymer interactions. The absorption features of HxNyOz, COx, and HCOOH (formic acid) were identified, and the relative densities were deduced by fitting the absorption bands of the detected molecules. Strong interactions between plasma and polymer (Polyethylene-2,6-naphthalate, or PEN) in precursor-free oxygen-containing gas mixtures were observed as evidenced by a high COx production. The presence of HCOOH in the gas effluent, formed through plasma-chemical synthesis of COx, turns out to be a sensitive indicator for etching. By adding tetraethylorthosilicate precursor in the plasma, dramatic changes in the COx production were measured, and two distinct deposition regimes were identified. At high precursor flows, a good agreement with the precursor combustion and the COx production was observed, whereas at low precursor flows an etching-deposition regime transpires, and the COx production is dominated by polymer etching.

  13. 33 CFR 151.67 - Operating requirements: Discharge of plastic prohibited.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... of plastic prohibited. 151.67 Section 151.67 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... Sewage § 151.67 Operating requirements: Discharge of plastic prohibited. No person on board any ship may discharge into the sea, or into the navigable waters of the United States, plastic or garbage mixed with...

  14. Influence of dust-particle concentration on gas-discharge plasma.

    PubMed

    Sukhinin, G I; Fedoseev, A V

    2010-01-01

    A self-consistent kinetic model of a low-pressure dc glow discharge with dust particles based on Boltzmann equation for the electron energy distribution function is presented. The ions and electrons production in ionizing processes as well as their recombination on the dust-particle surface and on the discharge tube wall were taken into account. The influence of dust-particle concentration N(d) on gas discharge and dust particles parameters was investigated. It is shown that the increase of N(d) leads to the increase of an averaged electric field and ion density, and to the decrease of a dust-particle charge and electron density in the dusty cloud. The results were obtained in a wide region of different discharge and dusty plasma parameters: dust particles density 10(2)-10(8) cm(-3), discharge current density 10(-1)-10(1) mA/cm(2), and dust particles radius 1, 2, and 5 microm. The scaling laws for dust-particle surface potential and electric filed dependencies on dust-particle density, particle radius and discharge currents were revealed. It is shown that the absorption of electrons and ions on the dust particles surface does not lead to the electron energy distribution function depletion due to a self-consistent adjustment of dust particles and discharge parameters.

  15. Decolorization of Indigo Carmine Solution using Discharge on Surface of a Gas-layer in Water

    NASA Astrophysics Data System (ADS)

    Miichi, Tomoaki

    A new method of a water treatment utilizing radicals produced by the discharge on the surface of a gas-layer in water is proposed. Radicals with short lifetime (e.g. OH radical and atomic oxygen) are used effectively for the water purification because radicals contact with water directly. The gas-layer (like a bubble) is formed when the gas is supplied to the reactor. The supply gas was argon. The indigo carmine solution was decolorized using the discharge on the surface of a gas-layer in water. The energy consumption of 1-pulse evaluated from waveforms of the applied voltage and the circuit current. When the total energy consumption was 5.46Wh, the decolorization rate of the indigo solution was 98.0%. The TOC concentration of the indigo solution which performed the discharge process was measured. When the charging voltage was 48.8kV, the treatment efficiency of TOC was 0.174g/kWh.

  16. Neutral gas temperature estimates and metastable resonance energy transfer for argon-nitrogen discharges

    SciTech Connect

    Greig, A., E-mail: amelia.greig@anu.edu.au; Charles, C.; Boswell, R. W.

    2016-01-15

    Rovibrational spectroscopy band fitting of the nitrogen (N{sub 2}) second positive system is a technique used to estimate the neutral gas temperature of N{sub 2} discharges, or atomic discharges with trace amounts of a N{sub 2} added. For mixtures involving argon and N{sub 2}, resonant energy transfer between argon metastable atoms (Ar*) and N{sub 2} molecules may affect gas temperature estimates made using the second positive system. The effect of Ar* resonance energy transfer is investigated here by analyzing neutral gas temperatures of argon-N{sub 2} mixtures, for N{sub 2} percentages from 1% to 100%. Neutral gas temperature estimates are highermore » than expected for mixtures involving greater than 5% N{sub 2} addition, but are reasonable for argon with less than 5% N{sub 2} addition when compared with an analytic model for ion-neutral charge exchange collisional heating. Additional spatiotemporal investigations into neutral gas temperature estimates with 10% N{sub 2} addition demonstrate that although absolute temperature values may be affected by Ar* resonant energy transfer, spatiotemporal trends may still be used to accurately diagnose the discharge.« less

  17. Modelling of the temporal evolution of the gas temperature in N2 discharges

    NASA Astrophysics Data System (ADS)

    Pintassilgo, Carlos D.; Guerra, Vasco

    2017-05-01

    The time-dependent evolution of the energy transfer to gas heating in a pure N2 discharge produced in a cylindrical tube at low pressures (1-10 Torr) is studied for different fixed values of the reduced electric field and electron density. We consider a model based on the self-consistent solutions to the time-dependent gas thermal balance equation coupled to the electron, vibrational, and chemical kinetic equations for the most important heavy species produced in N2 plasma discharges. The results of this model provide the temporal variation of the radially averaged value of the gas temperature, as well as the corresponding gas heating mechanisms. It is shown that the pooling reactions N2(A) + N2(A) → N2(B) + N2 and N2(A) + N2(A) → N2(C) + N2 are responsible for a smooth increase in the gas temperature before the first millisecond. For longer times, gas heating is found to be mainly caused by vibrational energy exchanges from non-resonant vibration-vibration (V-V) processes between N2 molecules and by vibration-translation (V-T) N2-N collisions. The heating rates of these different gas heating mechanisms and the gas temperature are calculated for a reduced electric field of 50 and 100 Td (1 Td = 10-17 Vcm2), an electron density of 1010 and 1011 cm-3, and a pressure of 1 and 10 Torr. The fractional power converted to gas heating from electronic and vibrational excitation is also calculated for these parameters, being respectively ˜2% and in the range 10%-35%. The effect of having a contribution of non-resonant V-V processes to gas cooling within the time interval 0.1-1 ms is analysed. The role of the gas temperature on the temporal evolution of the vibrational distribution of N2(X, v) molecules is also discussed.

  18. Binary and ternary gas mixtures with temperature enhanced diffuse glow discharge characteristics for use in closing switches

    DOEpatents

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

    1988-06-28

    An improvement to the gas mixture used in diffuse glow discharge closing switches is disclosed which includes binary and ternary gas mixtures which are formulated to exhibit decreasing electron attachment with increasing temperature. This increases the efficiency of the conductance of the glow discharge and further inhibits the formation of an arc. 11 figs.

  19. Binary and ternary gas mixtures with temperature enhanced diffuse glow discharge characteristics for use in closing switches

    DOEpatents

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

    1990-06-26

    An improvement to the gas mixture used in diffuse glow discharge closing switches is disclosed which includes binary and ternary gas mixtures which are formulated to exhibit decreasing electron attachment with increasing temperature. This increases the efficiency of the conductance of the glow discharge and further inhibits the formation of an arc. 11 figs.

  20. Binary and ternary gas mixtures with temperature enhanced diffuse glow discharge characteristics for use in closing switches

    DOEpatents

    Christophorou, Loucas G.; Hunter, Scott R.

    1990-01-01

    An improvement to the gas mixture used in diffuse glow discharge closing switches is disclosed which includes binary and ternary gas mixtures which are formulated to exhibit decreasing electron attachment with increasing temperature. This increases the efficiency of the conductance of the glow discharge and further inhibits the formation of an arc.

  1. Impact of gas flow rate on breakdown of filamentary dielectric barrier discharges

    SciTech Connect

    Höft, H., E-mail: hans.hoeft@inp-greifswald.de; Becker, M. M.; Kettlitz, M.

    2016-03-15

    The influence of gas flow rate on breakdown properties and stability of pulsed dielectric barrier discharges (DBDs) in a single filament arrangement using a gas mixture of 0.1 vol. % O{sub 2} in N{sub 2} at atmospheric pressure was investigated by means of electrical and optical diagnostics, accompanied by fluid dynamics and electrostatics simulations. A higher flow rate perpendicular to the electrode symmetry axis resulted in an increased breakdown voltage and DBD current maximum, a higher discharge inception jitter, and a larger emission diameter of the discharge channel. In addition, a shift of the filament position for low gas flow rates withmore » respect to the electrode symmetry axis was observed. These effects can be explained by the change of the residence time of charge carriers in the discharge region—i.e., the volume pre-ionization—for changed flow conditions due to the convective transport of particles out of the center of the gap.« less

  2. PREFACE: 12th International Conference on Gas Discharge Plasmas and Their Applications

    NASA Astrophysics Data System (ADS)

    Koval, N.; Landl, N.; Bogdan, A.; Yudin, A.

    2015-11-01

    The 12th International Conference ''Gas Discharge Plasmas and Their Applications'' (GDP 2015) was held in Tomsk, Russia, on September 6-11, 2015. GDP 2015 represents a continuation of the conferences on physics of gas discharge held in Russia since 1984 and seminars and conferences on the technological applications of low temperature plasmas traditionally organized in Tomsk. The six-day Conference brought together the specialists from different countries and organizations and provided an excellent opportunity to exchange knowledge, make oral contributions and poster presentations, and initiate discussions on the topics that are of interest to the Conference participants. The selected papers of the Conference cover a wide range of technical areas and modern aspects of the physical processes in the generators of low-temperature plasma, the low and high-pressure discharges, the pulsed plasma sources, the surface modification, and other gas-discharge technologies. The Conference was hosted by Institute of High Current Electronics SB RAS, Tomsk Polytechnic University, Tomsk Scientific Center, and Tomsk State University of Architecture and Building.

  3. Gas spark switches with increased operating life for Marx generator of lightning test complex

    SciTech Connect

    Bykov, Yu. A.; Krastelev, E. G., E-mail: ekrastelev@yandex.ru

    2016-12-15

    A new design of gas spark switches with an increased operating life and stable dynamic characteristics for the Marx generator of the lightning test complex has been developed. The switches are characterized by the following parameters in the mode of operation: voltage up to 80 kV, discharge current up to 50 kA, flowing charge up to 3.5 C/pulse. An increased operating life is achieved by using torus-shaped electrodes with increased working surface area and a trigger electrode in the form of a thick disk with a hole located between them. Low breakdown delay time and high stability of breakdown voltagemore » under dynamic conditions are provided by gas preionization in the spark gap using UV radiation of an additional corona discharge in the axial region.« less

  4. Gas spark switches with increased operating life for Marx generator of lightning test complex

    NASA Astrophysics Data System (ADS)

    Bykov, Yu. A.; Krastelev, E. G.

    2016-12-01

    A new design of gas spark switches with an increased operating life and stable dynamic characteristics for the Marx generator of the lightning test complex has been developed. The switches are characterized by the following parameters in the mode of operation: voltage up to 80 kV, discharge current up to 50 kA, flowing charge up to 3.5 C/pulse. An increased operating life is achieved by using torus-shaped electrodes with increased working surface area and a trigger electrode in the form of a thick disk with a hole located between them. Low breakdown delay time and high stability of breakdown voltage under dynamic conditions are provided by gas preionization in the spark gap using UV radiation of an additional corona discharge in the axial region.

  5. Simple experiment on the sputtering rate of solids in gas discharges

    NASA Astrophysics Data System (ADS)

    Hartmann, Peter; Reyes, Jorge C.; Korolov, Ihor; Matthews, Lorin S.; Hyde, Truell W.

    2017-06-01

    We present a very simple and sensitive method to measure the sputtering rate of solid materials in stationary low-pressure gas discharges. The method is based on the balance of the centrifugal force and the confinement electric force acting on a single electrically charged dust particle in a rotating environment. We demonstrate the use and sensitivity of this method in a capacitively coupled radio frequency argon discharge. We were able to detect a reduction of 10 nm in the diameter of a single dust particle.

  6. Evaluation of the potentials of humic acid removal in water by gas phase surface discharge plasma.

    PubMed

    Wang, Tiecheng; Qu, Guangzhou; Ren, Jingyu; Yan, Qiuhe; Sun, Qiuhong; Liang, Dongli; Hu, Shibin

    2016-02-01

    Degradation of humic acid (HA), a predominant type of natural organic matter in ground water and surface waters, was conducted using a gas phase surface discharge plasma system. HA standard and two surface waters (Wetland, and Weihe River) were selected as the targets. The experimental results showed that about 90.9% of standard HA was smoothly removed within 40 min's discharge plasma treatment at discharge voltage 23.0 kV, and the removal process fitted the first-order kinetic model. Roles of some active species in HA removal were studied by evaluating the effects of solution pH and OH radical scavenger; and the results presented that O3 and OH radical played significant roles in HA removal. Scanning electron microscope (SEM) and FTIR analysis showed that HA surface topography and molecular structure were changed during discharge plasma process. The mineralization of HA was analyzed by UV-Vis spectrum, dissolved organic carbon (DOC), specific UV absorbance (SUVA), UV absorption ratios, and excitation-emission matrix (EEM) fluorescence. The formation of disinfection by-products during HA sample chlorination was also identified, and CHCl3 was detected as the main disinfection by-product, but discharge plasma treatment could suppress its formation to a certain extent. In addition, approximately 82.3% and 67.9% of UV254 were removed for the Weihe River water and the Wetland water after 40 min of discharge plasma treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Radiation power control of the industrial CO2 lasers excited by a nonself-sustained glow discharge with regard to dissociation in a working gas mixture

    NASA Astrophysics Data System (ADS)

    Shemyakin, Andrey N.; Rachkov, Michael Yu.; Solovyov, Nikolay G.; Yakimov, Mikhail Yu.

    2018-01-01

    The action of a working gas mixture degradation related to the plasma chemical reactions in a glow discharge on the laser output power of the molecular laser excited by a nonself-sustained glow discharge has been studied by the example of an industrial laser of ;Lantan; CO2 laser series. It was found that the laser power overshoot when operating on a fresh gas mixture may exceed 3 times power level set in a steady-state regime. The working algorithm for the control system was proposed and developed setting standard fresh CO2/N2/He laser gas mixture to plasma chemical equilibrium composition during the laser turn-on procedure after full refill of a working gas mixture.

  8. Observation of carbon nanotube filament bridging induced by gas discharge breakdown between electrodes

    NASA Astrophysics Data System (ADS)

    Mizushima, Yuuki; Sato, Hideki

    2018-01-01

    We have recently found that discharge breakdown between a pair of electrodes, one of which is covered by carbon nanotubes (CNTs), results in the formation of CNT filaments, comprising many short bundles of CNTs and bridging the two electrodes. We have also found that this is triggered by the spark discharge of the ambient gas and is significantly affected by the morphology of the initial CNT film. This phenomenon may provide a suitable method for spinning CNTs, particularly for short CNTs (lengths <100 µm). Here, we examined the formation of CNT filaments in detail to understand the formation mechanism. The voltage required for the filament formation was markedly lowered by reducing the interelectrode distance. A temporal observation showed that the formation is completed within 500 ms from the start of discharge. The filaments after being formed could be elongated by increasing the interelectrode distance. This is favorable for the spinning of CNTs.

  9. Compressor discharge bleed air circuit in gas turbine plants and related method

    DOEpatents

    Anand, Ashok Kumar [Niskayuna, NY; Berrahou, Philip Fadhel [Latham, NY; Jandrisevits, Michael [Clifton Park, NY

    2003-04-08

    A gas turbine system that includes a compressor, a turbine component and a load, wherein fuel and compressor discharge bleed air are supplied to a combustor and gaseous products of combustion are introduced into the turbine component and subsequently exhausted to atmosphere. A compressor discharge bleed air circuit removes bleed air from the compressor and supplies one portion of the bleed air to the combustor and another portion of the compressor discharge bleed air to an exhaust stack of the turbine component in a single cycle system, or to a heat recovery steam generator in a combined cycle system. In both systems, the bleed air diverted from the combustor may be expanded in an air expander to reduce pressure upstream of the exhaust stack or heat recovery steam generator.

  10. Compressor discharge bleed air circuit in gas turbine plants and related method

    DOEpatents

    Anand, Ashok Kumar; Berrahou, Philip Fadhel; Jandrisevits, Michael

    2002-01-01

    A gas turbine system that includes a compressor, a turbine component and a load, wherein fuel and compressor discharge bleed air are supplied to a combustor and gaseous products of combustion are introduced into the turbine component and subsequently exhausted to atmosphere. A compressor discharge bleed air circuit removes bleed air from the compressor and supplies one portion of the bleed air to the combustor and another portion of the compressor discharge bleed air to an exhaust stack of the turbine component in a single cycle system, or to a heat recovery steam generator in a combined cycle system. In both systems, the bleed air diverted from the combustor may be expanded in an air expander to reduce pressure upstream of the exhaust stack or heat recovery steam generator.

  11. ACTIVE MEDIA: Multifrequency laser probing of CO-containing gas mixtures excited in a pulsed discharge

    NASA Astrophysics Data System (ADS)

    Ionin, Andrei A.; Klimachev, Yu M.; Kozlov, A. Yu; Kotkov, A. A.; Rulev, O. A.; Seleznev, L. V.; Sinitsyn, D. V.

    2007-03-01

    The method of multifrequency laser probing is developed which can be used for diagnostics of the temperature and population of vibrational levels in gas mixtures containing CO molecules in excited vibrational states. The method is tested by studying the dynamics of the gas temperature and population of vibrational levels of the CO molecule in gas mixtures excited by a pulsed discharge. It is shown that the method provides the reduction of the gas temperature measurement error down to 3%. It is found that the population of lower vibrational levels in the CO-O2 mixture can exceed the population of levels in CO-He and CO-N2 laser mixtures by several times.

  12. Numerical simulation of operation modes in atmospheric pressure uniform barrier discharge excited by a saw-tooth voltage

    SciTech Connect

    Li Xuechen; Niu Dongying; Yin Zengqian

    2012-08-15

    The characteristics of dielectric barrier discharge excited by a saw-tooth voltage are simulated in atmospheric pressure helium based on a one-dimensional fluid model. A stepped discharge is obtained per half voltage cycle with gas gap width less than 2 mm by the simulation, which is different to the pulsed discharge excited by a sinusoidal voltage. For the stepped discharge, the plateau duration increases with increasing the voltage amplitude and decreasing the gas gap. Therefore, uniform discharge with high temporal duty ratio can be realized with small gap through increasing the voltage amplitude. The maximal densities of both electron and ionmore » appear near the anode and the electric field is almost uniformly distributed along the gap, which indicates that the stepped discharge belongs to a Townsend mode. In contrast to the stepped discharge with small gas gap, a pulsed discharge can be obtained with large gas gap. Through analyzing the spatial density distributions of electron and ion and the electric field, the pulsed discharge is in a glow mode. The voltage-current (V-I) characteristics are analyzed for the above mentioned discharges under different gas gaps, from which the different discharge modes are verified.« less

  13. Numerical simulation of operation modes in atmospheric pressure uniform barrier discharge excited by a saw-tooth voltage

    SciTech Connect

    Li Xuechen; Niu Dongying; Yin Zengqian; Fang Tongzhen; Wang Long

    2012-08-15

    The characteristics of dielectric barrier discharge excited by a saw-tooth voltage are simulated in atmospheric pressure helium based on a one-dimensional fluid model. A stepped discharge is obtained per half voltage cycle with gas gap width less than 2 mm by the simulation, which is different to the pulsed discharge excited by a sinusoidal voltage. For the stepped discharge, the plateau duration increases with increasing the voltage amplitude and decreasing the gas gap. Therefore, uniform discharge with high temporal duty ratio can be realized with small gap through increasing the voltage amplitude. The maximal densities of both electron and ion appear near the anode and the electric field is almost uniformly distributed along the gap, which indicates that the stepped discharge belongs to a Townsend mode. In contrast to the stepped discharge with small gas gap, a pulsed discharge can be obtained with large gas gap. Through analyzing the spatial density distributions of electron and ion and the electric field, the pulsed discharge is in a glow mode. The voltage-current (V-I) characteristics are analyzed for the above mentioned discharges under different gas gaps, from which the different discharge modes are verified.

  14. Numerical simulation of electroionisation and electric-discharge gas flow CO lasers

    SciTech Connect

    Araslanov, Sh F; Safiullin, R K

    2001-08-31

    An effecient method is developed for numerical investigation of gas flow electric-discharge and electroionisation CO lasers. The model includes a set of vibrational kinetic equations, the equation for the electron energy distribution function, and radiative gas-dynamics equations. The proposed method is based on the splitting of the system of equations into several subsystems corresponding to different physical processes (splitting method). Populations of vibrational levels, the gains, the emission line intensities, the output power, and the efficiency of CO lasers are calculated and compared with the experimental data. (lasers and amplifiers)

  15. Theory of a stationary microwave discharge with multiply charged ions in an expanding gas jet

    SciTech Connect

    Shalashov, A. G., E-mail: ags@appl.sci-nnov.ru; Abramov, I. S.; Golubev, S. V.

    2016-08-15

    The formation of a jet of a nonequilibrium multiply charged ion plasma is studied in the inhomogeneous gas jet. It is shown that the geometrical divergence of the jet restricts the maximum ion charge state and results in the spatial localization of the discharge. Stationary solutions corresponding to such regimes are constructed. The model proposed can be used to optimize modern experiments on generation of hard UV radiation due to the line emission of multiply ionized atoms in a gas jet heated by high-power millimeter and submillimeter radiation.

  16. A discussion on maximum charge held by a single particle due to gas discharge limitation

    NASA Astrophysics Data System (ADS)

    Matsuyama, Tatsushi

    2018-02-01

    Generation of contact electrification or tribo-charging consists of two processes as (1) contact and charge transfer, and (2) separation and charge fixation. To discuss the rate process of charge development the process (1) is important but process (2) is also important to discuss the maximum or equilibrium charge held by a particle. Especially in normal air, the amount of charge held by a single particle can be limited due to gas discharge. This limitation has been discussed in the relationship between Paschen's gas breakdown limit and potential curve of particle surface in the vicinity of metal target. In the previous works, estimated maximum charges and results of experiments using single particles showed good agreements. On the other hand, "modified Paschen" attracted interest recently, for micro-gap discharge region, in which such gas breakdown between particle and metal target in such contact and separation process can take place. In this paper, the maximum charge held by a single particle as a function of particle size is discussed in details, with comparing the cases using conventional Paschen curve and modified Paschen to give the gas breakdown limit potential. The results showed a 50 µm as a critical particle size to transfer maximum charge determined by conventional Paschen to modified Paschen. However, a few experimental reports (in citations) showed higher gas breakdown resistivity in such micro-gap range less than 5µm.

  17. HIGH-VOLTAGE GLOW DISCHARGES IN D$sub 2$ GAS. III. STARTING POTENTIAL THEORY

    SciTech Connect

    Granzow, K.D.; McClure, G.W.

    1962-03-15

    A theoretical treatment of the left branch of the Paschen urve for parallel plate discharges in D/sub 2/ gas is presented for potentials at 5 to 120 kv. The effect of electrons back;attered from the anode is considered and found to be ignificant. The Paschen curve is extremely sensitive to we secondary emission coefficient at low energies. The ign of the slope of the Paschen curve depends on the nergy dependence of the secondary emission coefficient. auth)

  18. Electron beam method and apparatus for obtaining uniform discharges in electrically pumped gas lasers

    DOEpatents

    Fenstermacher, Charles A.; Boyer, Keith

    1986-01-01

    A method and apparatus for obtaining uniform, high-energy, large-volume electrical discharges in the lasing medium of a gas laser whereby a high-energy electron beam is used as an external ionization source to ionize substantially the entire volume of the lasing medium which is then readily pumped by means of an applied potential less than the breakdown voltage of the medium. The method and apparatus are particularly useful in CO.sub.2 laser systems.

  19. Visible and near-ultraviolet spectra of low-pressure rare-gas microwave discharges

    NASA Technical Reports Server (NTRS)

    Campbell, J. P.; Spisz, E. W.; Bowman, R. L.

    1971-01-01

    The spectral emission characteristics of three commercial low pressure rare gas discharge lamps wire obtained in the near ultraviolet and visible wavelength range. All three lamps show a definite continuum over the entire wavelength range from 0.185 to 0.6 micrometers. Considerable line emission is superimposed on much of the continuum for wavelengths greater than 0.35 micrometers. These sources were used to make transmittance measurements on quartz samples in the near ultraviolet wavelength range.

  20. Physics and Chemistry of MW Laser-induced Discharge in Gas Flows and Plasma Jets

    DTIC Science & Technology

    2007-12-01

    can be quasi-stationary coaxial plasma accelerators (MPC). This type of accelerators generates plasma jets of different gases (H2, He, N2, Ar) with...gas is ionizing and accelerating in discharge processing. For this regime the plasma gun generates the plasma jets of different gases3 (H2, He, N2...spectrometers. Spectrometers 1 and 2 are used for measuring of time behavior of single spectral lines, emitting in the focus area of plasma gun . Usually

  1. Generation of underwater discharges inside gas bubbles using a 30-needles-to-plate electrode

    NASA Astrophysics Data System (ADS)

    Chen, Zhiqiang; Krasik, Yakov E.; Cousens, Samuel; Ambujakshan, Arun T.; Corr, Cormac; Dai, Xiujuan J.

    2017-10-01

    Underwater discharges inside helium (He) gas bubbles were generated using a 30-needles-to-plate electrode system with the gas flowing through the needles. The set-up allows continuous treatment of flowing water. The plasma electron temperature and density determined from spectral line intensities and profiles of the Hα and Hβ hydrogen lines were found to be 1.1 ± 0.6 eV and ˜5 × 1016 cm-3, respectively. These parameters are comparable with those of plasmas generated by other underwater gas bubble discharges for the production of OH radicals. The two main long-lived species, hydrogen peroxide (H2O2) and nitrate ions (NO3-), produced in plasma treated water were measured. It was found that without a continuous water flow, the energy yield of H2O2 was comparable with other underwater discharges, while with a continuous flow, the production of H2O2 appeared to be somewhat reduced by nitrites from dissolved air.

  2. Dynamics of spiral patterns in gas discharge detected by optical method

    NASA Astrophysics Data System (ADS)

    Yang, Fan; Wang, Mingyi; Liu, Shuhua

    2016-09-01

    The dynamics behavior of spiral patterns is investigated in gas discharge using optical method. Rich kinks of spiral patterns are obtained and the formation and evolution process is investigated. The process of pattern formation is breakdown -> hexagon -> bee comb-like -> strip -> spiral -> chaos. Spiral pattern always formed after the strip pattern. It is found that the temperature of the water electrodes plays an important role in the spiral patterns formation. When it exceeds 20°C no spiral has been obtained. The discharge current waveform and the emission spectrum of the discharge have been measured when the filaments self-organized in spiral pattern. Electron excited temperature of forming spiral pattern is calculated using intensity ratio method. It is found that the electron excited temperature of spiral pattern increase as the power supply frequency increased. Relation between wavelength and discharge parameter has been measured. It shows that the wavelength of spiral pattern increases as the discharge gap increases, and decreases as the air ratio mixed in argon increases. Accompanying measurements proved that the wavelength is approximately linear to the square root of the spiral rotating period .This work has useful reference value for studying pattern dynamics.

  3. Optical and electrostatic potential investigations of electrical breakdown phenomena in a low-pressure gas discharge lamp

    NASA Astrophysics Data System (ADS)

    Gendre, M. F.; Haverlag, M.; Kroesen, G. M. W.

    2010-06-01

    The ignition phase is a critical stage in the operation of gas discharge lamps where the neutral gas enclosed between the electrodes undergoes a transformation from the dielectric state to a conducting phase, eventually enabling the production of light. The phenomena occurring during this phase transition are not fully understood and the related experimental studies are often limited to local optical measurements in environments prone to influencing these transient phenomena. In this work unipolar ignition phenomena at sub-kilovolt levels are investigated in a 3 Torr argon discharge tube. The lamp is placed in a highly controlled environment so as to prevent any bias on the measurements. A fast intensified CCD camera and a specially designed novel electrostatic probe are used simultaneously so as to provide a broad array of measured and computed parameters which are displayed in space-time diagrams for cross comparisons. Experiments show that three distinct phases exist during successful ignitions: upon the application of voltage a first ionization wave starts from the active electrode and propagates in the neutral gas towards the opposite electrode. A local front of high axial E field strength is associated with this process and causes a local ionization to occur, leading to the electrostatic charging of the lamp. Next, a second wave propagates from the ground electrode back towards the active electrode with a higher velocity, and in this process leads to a partial discharging of the lamp. This return stroke draws a homogeneous plasma column which eventually bridges both electrodes at the end of the wave propagation. At this point both electrode sheaths are formed and the common features of a glow discharge are observed. The third phase is an increase in the light intensity of the plasma column until the lamp reaches a steady-state operation. Failed ignitions present only the first phase where the first wave starts its propagation but extinguishes in the lamp

  4. Towards sustainability in offshore oil and gas operations

    NASA Astrophysics Data System (ADS)

    Khan, M. Ibrahim

    Human activities are causing irreversible damage to the natural world and threaten our ability to sustain future generations. According to Millennium Ecosystem Assessment of 2005, sixty percent of world pristine habitats are destroyed or disturbed and species extinction rate is 100-1000 times higher than the normal background rate. One of the main reasons of these problems is the use of unsustainable technology. In this dissertation, the essential features of the modern technology development are discussed and a new single-parameter screening criterion is proposed. This criterion will allow the development of truly sustainable technologies. Previously developed technologies, particularly the ones developed after the industrial revolution, are evaluated based on the new criterion. The root cause for unsustainability of these technologies especially in the energy sector is discussed. The proposed criterion is applied to the petroleum sector. Petroleum hydrocarbons are considered to be the lifeblood of the modern society. Petroleum industry that took off from the golden era of 1930's never ceased to dominate all aspects of our society. Until now, there is no suitable alternative to fossil fuel and all trends indicate continued dominance of the petroleum industry in the foreseeable future. Even though petroleum operations have been based on solid scientific excellence and engineering marvels; only recently it has been discovered that many of the practices are not environmentally sustainable. Practically all activities of hydrocarbon operations are accompanied by undesirable discharges of liquid, solid, and gaseous wastes, which have enormous impacts on the environment. Consequently, reducing environmental impact is the most pressing issue today and many environmentalist groups are calling for curtailing petroleum operations altogether. There is clearly a need to develop a new management approach in hydrocarbon operations. This approach will have to be environmentally

  5. Compressed Natural Gas Safety in Transit Operations

    DOT National Transportation Integrated Search

    1995-09-14

    This report examines the safety issues relating to the use of Compressed Natural Gas (CNG) in transit service. The safety issues were determined by on-site surveys performed by Battelle of Columbus, Ohio and Science Applications International Corpora...

  6. Nondestructive Evaluation of the J-2X Direct Metal Laser Sintered Gas Generator Discharge Duct

    NASA Technical Reports Server (NTRS)

    Esther, Elizabeth A.; Beshears, Ronald D.; Lash, Rhonda K.

    2012-01-01

    The J-2X program at NASA's Marshall Space Flight Center (MSFC) procured a direct metal laser sintered (DMLS) gas generator discharge duct from Pratt & Whitney Rocketdyne and Morris Technologies for a test program that would evaluate the material properties and durability of the duct in an engine-like environment. DMLS technology was pursued as a manufacturing alternative to traditional techniques, which used off nominal practices to manufacture the gas generator duct's 180 degree turn geometry. MSFC's Nondestructive Evaluation (NDE) Team performed radiographic, ultrasonic, computed tomographic, and fluorescent penetrant examinations of the duct. Results from the NDE examinations reveal some shallow porosity but no major defects in the as-manufactured material. NDE examinations were also performed after hot-fire testing the gas generator duct and yielded similar results pre and post-test and showed no flaw growth or development.

  7. Effect of hydrogen ratio on plasma parameters of N{sub 2}-H{sub 2} gas mixture glow discharge

    SciTech Connect

    El-Brulsy, R. A.; Abd Al-Halim, M. A.; Abu-Hashem, A.; Rashed, U. M.; Hassouba, M. A.

    2012-05-15

    A dc plane glow discharge in a nitrogen-hydrogen (N{sub 2}-H{sub 2}) gas mixture has been operated at discharge currents of 10 and 20 mA. The electron energy distribution function (EEDF) at different hydrogen concentrations is measured. A Maxwellian EEDF is found in the positive column region, while in both cathode fall and negative glow regions, a non-Maxwellian one is observed. Langmuir electric probes are used at different axial positions, gas pressures, and hydrogen concentrations to measure the electron temperature and plasma density. The electron temperature is found to increase with increasing H{sub 2} concentration and decrease with increasing both the axial distance from the cathode and the mixture pressure. At first, with increasing distance from the cathode, the ion density decreases, while the electron density increases; then, as the anode is further approached, they remain nearly constant. At different H{sub 2} concentrations, the electron and ion densities decrease with increasing the mixture pressure. Both the electron and ion densities slightly decrease with increasing H{sub 2} concentration.

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

  9. Plasma Discharges in Gas Bubbles in Liquid Water: Breakdown Mechanisms and Resultant Chemistry

    NASA Astrophysics Data System (ADS)

    Gucker, Sarah M. N.

    The use of atmospheric pressure plasmas in gases and liquids for purification of liquids has been investigated by numerous researchers, and is highly attractive due to their strong potential as a disinfectant and sterilizer. However, the fundamental understanding of plasma production in liquid water is still limited. Despite the decades of study dedicated to electrical discharges in liquids, many physical aspects of liquids, such as the high inhomogeneity of liquids, complicate analyses. For example, the complex nonlinearities of the fluid have intricate effects on the electric field of the propagating streamer. Additionally, the liquid material itself can vaporize, leading to discontinuous liquid-vapor boundaries. Both can and do often lead to notable hydrodynamic effects. The chemistry of these high voltage discharges on liquid media can have circular effects, with the produced species having influence on future discharges. Two notable examples include an increase in liquid conductivity via charged species production, which affects the discharge. A second, more complicated scenario seen in some liquids (such as water) is the doubling or tripling of molecular density for a few molecule layers around a high voltage electrode. These complexities require technological advancements in optical diagnostics that have only recently come into being. This dissertation investigates several aspects of electrical discharges in gas bubbles in liquids. Two primary experimental configurations are investigated: the first allows for single bubble analysis through the use of an acoustic trap. Electrodes may be brought in around the bubble to allow for plasma formation without physically touching the bubble. The second experiment investigates the resulting liquid phase chemistry that is driven by the discharge. This is done through a dielectric barrier discharge with a central high voltage surrounded by a quartz discharge tube with a coil ground electrode on the outside. The plasma

  10. Scenario Analysis of the Impact on Drinking Water Intakes from Bromide in the Discharge of Treated Oil and Gas Wastewater

    EPA Pesticide Factsheets

    EPA scientists created different scenarios for conventional commercial wastewater treatment plants that treat oil and gas wastewaters to evaluate the impact from bromide in discharges by the CWTP plants.

  11. ZnO Nanowire-Based Corona Discharge Devices Operated Under Hundreds of Volts

    NASA Astrophysics Data System (ADS)

    Yang, Wenming; Zhu, Rong; Zong, Xianli

    2016-02-01

    Minimizing the voltage of corona discharges, especially when using nanomaterials, has been of great interest in the past decade or so. In this paper, we report a new corona discharge device by using ZnO nanowires operated in atmospheric air to realize continuous corona discharge excited by hundreds of volts. ZnO nanowires were synthesized on microelectrodes using electric-field-assisted wet chemical method, and a thin tungsten film was deposited on the microchip to enhance discharging performance. The testing results showed that the corona inception voltages were minimized greatly by using nanowires compared to conventional dischargers as a result of the local field enhancement of nanowires. The corona could be continuously generated and self-sustaining. It was proved that the law of corona inception voltage obeyed the conventional Peek's breakdown criterion. An optimal thickness of tungsten film coated over ZnO nanowires was figured out to obtain the lowest corona inception voltage. The ion concentration of the nanowire-based discharger attained 1017/m3 orders of magnitude, which is practicable for most discharging applications.

  12. ZnO Nanowire-Based Corona Discharge Devices Operated Under Hundreds of Volts.

    PubMed

    Yang, Wenming; Zhu, Rong; Zong, Xianli

    2016-12-01

    Minimizing the voltage of corona discharges, especially when using nanomaterials, has been of great interest in the past decade or so. In this paper, we report a new corona discharge device by using ZnO nanowires operated in atmospheric air to realize continuous corona discharge excited by hundreds of volts. ZnO nanowires were synthesized on microelectrodes using electric-field-assisted wet chemical method, and a thin tungsten film was deposited on the microchip to enhance discharging performance. The testing results showed that the corona inception voltages were minimized greatly by using nanowires compared to conventional dischargers as a result of the local field enhancement of nanowires. The corona could be continuously generated and self-sustaining. It was proved that the law of corona inception voltage obeyed the conventional Peek's breakdown criterion. An optimal thickness of tungsten film coated over ZnO nanowires was figured out to obtain the lowest corona inception voltage. The ion concentration of the nanowire-based discharger attained 10(17)/m(3) orders of magnitude, which is practicable for most discharging applications.

  13. Frequency of diagnosis of cancer or high-risk lesion at operation for pathologic nipple discharge.

    PubMed

    Dupont, Sean C; Boughey, Judy C; Jimenez, Rafael E; Hoskin, Tanya L; Hieken, Tina J

    2015-10-01

    Pathologic nipple discharge is managed customarily with diagnostic subareolar duct excision. We evaluated for features predictive of malignancy to identify cases where operation might be avoided. We studied 311 consecutive subareolar duct excisions for pathologic nipple discharge from January 2008 to July 2014. χ(2) tests were used to test for associations with final pathology. In 27 cases, cancer was diagnosed preoperatively. Among the remaining 284, 26 (9%) were diagnosed with cancer and 8 (3%) with atypia at operation. At greatest risk of upstage to cancer were patients with prior ipsilateral breast cancer (3/8; 38%), BRCA mutation (2/3; 67%) or atypia on core needle biopsy (CNB; 3/8 [38%]). Excluding these patients lowered cancer and atypia upstages (7% [18/265] and 3% [7/265]), with bloody (versus serous) discharge (P = .001), and focal imaging abnormality (P = .02), the strongest risk factors. Serous discharge and either normal imaging or a benign CNB had a 1.3% cancer upstage rate. Despite contemporary imaging, pathologic nipple discharge upstage rates to malignancy and atypia remain high, especially with prior ipsilateral breast cancer, BRCA mutation, or atypia on CNB. Absent these risk factors, patients with serous discharge and a benign CNB or normal imaging (cancer risk <2%) may be considered for nonoperative management. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Characteristics of gas-liquid diaphragm discharge and its application on decolorization of brilliant red B in aqueous solution

    NASA Astrophysics Data System (ADS)

    Qingsong, GAO; Yongjun, LIU; Bing, SUN

    2017-11-01

    A simple gas-liquid diaphragm discharge reactor was designed and characteristics of the discharge and its application on decolorization of brilliant red B in an aqueous solution were investigated. The results showed that strong oxidizing agents such as ·OH and ·O radicals were generated. Average electron temperature of the discharge was 0.72 eV, 1.15 eV and 0.83 eV with air, oxygen and argon as the discharge gas, respectively. Solution pH and conductivity changed little when oxygen or argon was used as the discharge gas; however, these two parameters changed significantly when the discharge was performed in air. During the discharge treatment, the characteristic absorption peaks of brilliant red B gradually decreased where the decolorization followed the first-order kinetics. With 10 min of discharge, the decolorization of brilliant red B (30 mg L-1) can reach 96%, 81% and 62% in the cases of oxygen, argon and air, respectively. The analysis of by-products showed that the brilliant red B molecule can be effectively destroyed in this discharge mode.

  15. Magnetic Ignition of Pulsed Gas Discharges in Air of Low Pressure in a Coaxial Plasma Gun

    NASA Technical Reports Server (NTRS)

    Thom, Karlheinz; Norwood, Joseph, Jr.

    1961-01-01

    The effect of an axial magnetic field on the breakdown voltage of a coaxial system of electrodes has been investigated by earlier workers. For low values of gas pressure times electrode spacing, the breakdown voltage is decreased by the application of the magnetic field. The electron cyclotron radius now assumes the role held by the mean free path in nonmagnetic discharges and the breakdown voltage becomes a function of the magnetic flux density. In this paper the dependence of the formative time lag as a function of the magnetic flux density is established and the feasibility of using a magnetic field for igniting high-voltage, high-current discharges is shown through theory and experiment. With a 36 microfarad capacitor bank charged to 48,000 volts, a peak current of 1.3 x 10( exp 6) amperes in a coaxial type of plasma gun was achieved with a current rise time of only 2 microseconds.

  16. Effects of water vapor on flue gas conditioning in the electric fields with corona discharge.

    PubMed

    Liqiang, Qi; Yajuan, Zhang

    2013-07-15

    Sulfur dioxide (SO2) removal via pulsed discharge nonthermal plasma in the absence of ammonia was investigated to determine how electrostatic precipitators (ESPs) can effectively collect particulate matter less than 2.5μm in diameter from flue gas. SO2 removal increased as water vapor concentration increased. In a wet-type plasma reactor, directing a gas-phase discharge plasma toward the water film surface significantly enhanced the liquid-phase oxidation of HSO3(-) to SO4(2-). Comparisons of various absorbents revealed that the hydroxyl radical is a key factor in plasma-induced liquid-phase reactions. The resistivity, size distribution, and cohesive force of fly ash at different water vapor contents were measured using a Bahco centrifuge, which is a dust electrical resistivity test instrument, as well as a cohesive force test apparatus developed by the researchers. When water vapor content increased by 5%, fly ash resistivity in flue gas decreased by approximately two orders of magnitude, adhesive force and size increased, and specific surface area decreased. Therefore, ESP efficiency increased. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Experimental biological effects assessment associated with on-shore brine discharge from the creation of gas storage caverns

    NASA Astrophysics Data System (ADS)

    Quintino, Victor; Rodrigues, Ana Maria; Freitas, Rosa; Ré, Ana

    2008-09-01

    Most of the studies on biological and ecological effects associated with brine discharge into the marine environment are related to the operation of desalination plants, for the production of freshwater. In this study we analysed the biological effects of a brine effluent from a completely different source, produced from the lixiviation of rock salt caves, for the creation of natural gas storage caverns. Lethal and sub-lethal endpoints following exposure to the brine were studied in a range of macrofauna species characteristic of the soft and hard bottom habitats in the vicinity of the discharge area, namely the isopod Eurydice pulchra, the annelids Sabellaria alveolata and Ophelia radiata, the sea-urchin Paracentrotus lividus and the bivalve Mytilus galloprovincialis. In a first series of experiments, brine, with salinity above 300, was diluted in distilled water to a salinity value close to that of the seawater in the discharge area (salinity 36) and, surprisingly, none of the exposed species was able to survive or develop into viable larvae. A second series of experiments exposed the species to brine diluted with seawater, simulating more realistic discharge circumstances. All the tested species at all the measured endpoints (adult survival, larval abnormal development, sperm fertilization success) showed negative biological effects in brine solutes always at a lower salinity than that of a salinity control obtained with concentrated seawater. The sub-lethal experiments with larval development of P. lividus, S. alveolata and M. galloprovincialis, and the fertilization success of P. lividus gave EC 50 values for the brine solute with salinity in the range of 40.9-43.5, whereas the EC 50 values for the concentrated seawater were in the range of salinity 44.2-49.0. It is hypothesised that differences in the ionic composition of the brine cause the inability of the species to tolerate the exposure to brine.

  18. Ozone generation in a kHz-pulsed He-O2 capillary dielectric barrier discharge operated in ambient air

    NASA Astrophysics Data System (ADS)

    Sands, Brian L.; Ganguly, Biswa N.

    2013-12-01

    The generation of reactive oxygen species using nonequilibrium atmospheric pressure plasma jet devices has been a subject of recent interest due to their ability to generate localized concentrations from a compact source. To date, such studies with plasma jet devices have primarily utilized radio-frequency excitation. In this work, we characterize ozone generation in a kHz-pulsed capillary dielectric barrier discharge configuration comprised of an active discharge plasma jet operating in ambient air that is externally grounded. The plasma jet flow gas was composed of helium with an admixture of up to 5% oxygen. A unipolar voltage pulse train with a 20 ns pulse risetime was used to drive the discharge at repetition rates between 2-25 kHz. Using UVLED absorption spectroscopy centered at 255 nm near the Hartley-band absorption peak, ozone was detected over 1 cm from the capillary axis. We observed roughly linear scaling of ozone production with increasing pulse repetition rate up to a "turnover frequency," beyond which ozone production steadily dropped and discharge current and 777 nm O(5P→5S°) emission sharply increased. The turnover in ozone production occurred at higher pulse frequencies with increasing flow rate and decreasing applied voltage with a common energy density of 55 mJ/cm3 supplied to the discharge. The limiting energy density and peak ozone production both increased with increasing O2 admixture. The power dissipated in the discharge was obtained from circuit current and voltage measurements using a modified parallel plate dielectric barrier discharge circuit model and the volume-averaged ozone concentration was derived from a 2D ozone absorption measurement. From these measurements, the volume-averaged efficiency of ozone production was calculated to be 23 g/kWh at conditions for peak ozone production of 41 mg/h at 11 kV applied voltage, 3% O2, 2 l/min flow rate, and 13 kHz pulse repetition rate, with 1.79 W dissipated in the discharge.

  19. Evolution of a vortex in gas-discharge plasma with allowance for gas compressibility

    NASA Astrophysics Data System (ADS)

    Sukhomlinov, V. S.; Mustafaev, A. S.

    2016-09-01

    The dynamics of a vortex tube in a compressible medium with the Rayleigh energy release mechanism has been considered theoretically. The analytic theory of this phenomenon is constructed and various approximations have been considered. The range of applicability conditions for the vortex formation theory has been extended substantially. It has been shown based on the model of a plasma as a Rayleigh medium that, for a certain relative orientation of the vortex axis and the electric field vector at an air pressure of tens of Torr, a vortex tube in the glow discharge plasma is destroyed over time intervals on the order of hundredths of a second. It has been found that allowance for the compressibility leads to an increase in the rate of vortex destruction. For this medium, the time dependences of the tangential velocity in a vortex tube have been calculated for various initial parameters. The similarity rules for the given phenomena and the universal dependence of the vortex tube dynamics have been obtained.

  20. A bank-operated traveling-block cableway for stream discharge and sediment measurements

    Treesearch

    James J. Paradiso

    2000-01-01

    Streams often present a challenge for collecting flow and sediment measurements on a year-round basis. Streams that can normally be waded become hazardous during seasonal flows, either endangering hydrographers or precluding data collection completely. A hand-operated cableway permits the accurate and safe collection of discharge and sediment data from the stream bank...

  1. 20 CFR 726.207 - Discharge by the carrier of obligations and duties of operator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 4 2013-04-01 2013-04-01 false Discharge by the carrier of obligations and duties of operator. 726.207 Section 726.207 Employees' Benefits OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR FEDERAL COAL MINE HEALTH AND SAFETY ACT OF 1969, AS AMENDED BLACK LUNG BENEFITS...

  2. 20 CFR 726.207 - Discharge by the carrier of obligations and duties of operator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 4 2014-04-01 2014-04-01 false Discharge by the carrier of obligations and duties of operator. 726.207 Section 726.207 Employees' Benefits OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR FEDERAL COAL MINE HEALTH AND SAFETY ACT OF 1969, AS AMENDED BLACK LUNG BENEFITS...

  3. 20 CFR 726.207 - Discharge by the carrier of obligations and duties of operator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 4 2012-04-01 2012-04-01 false Discharge by the carrier of obligations and duties of operator. 726.207 Section 726.207 Employees' Benefits OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR FEDERAL COAL MINE HEALTH AND SAFETY ACT OF 1969, AS AMENDED BLACK LUNG BENEFITS...

  4. 33 CFR 151.67 - Operating requirements: Discharge of plastic prohibited.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... plastic, including, but not limited to, synthetic ropes, synthetic fishing nets, and plastic garbage bags... of plastic prohibited. 151.67 Section 151.67 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... Sewage § 151.67 Operating requirements: Discharge of plastic prohibited. No person on board any ship may...

  5. Greenhouse gas balance for composting operations.

    PubMed

    Brown, Sally; Kruger, Chad; Subler, Scott

    2008-01-01

    The greenhouse gas (GHG) impact of composting a range of potential feedstocks was evaluated through a review of the existing literature with a focus on methane (CH(4)) avoidance by composting and GHG emissions during composting. The primary carbon credits associated with composting are through CH(4) avoidance when feedstocks are composted instead of landfilled (municipal solid waste and biosolids) or lagooned (animal manures). Methane generation potential is given based on total volatile solids, expected volatile solids destruction, and CH(4) generation from lab and field incubations. For example, a facility that composts an equal mixture of manure, newsprint, and food waste could conserve the equivalent of 3.1 Mg CO(2) per 1 dry Mg of feedstocks composted if feedstocks were diverted from anaerobic storage lagoons and landfills with no gas collection mechanisms. The composting process is a source of GHG emissions from the use of electricity and fossil fuels and through GHG emissions during composting. Greenhouse gas emissions during composting are highest for high-nitrogen materials with high moisture contents. These debits are minimal in comparison to avoidance credits and can be further minimized through the use of higher carbon:nitrogen feedstock mixtures and lower-moisture-content mixtures. Compost end use has the potential to generate carbon credits through avoidance and sequestration of carbon; however, these are highly project specific and need to be quantified on an individual project basis.

  6. Dynamics of the water molecule density in a discharge chamber filled with a low-pressure humid gas

    SciTech Connect

    Bernatskiy, A. V., E-mail: berav@sci.lebedev.ru; Ochkin, V. N., E-mail: ochkin@sci.lebedev.ru; Bafoev, R. N.

    2016-10-15

    The dynamics of the H{sub 2}O molecule density in a metal gas-discharge chamber filled with low-pressure water vapor or its mixtures with noble gases was investigated by manometric and spectral methods. Regimes both with and without discharge excitation were studied. In the absence of a discharge, the molecule density dynamics is governed by the heterogeneous interaction of molecules with the chamber walls. In the presence of a discharge, in addition to the heterogeneous interaction, fast plasmachemical molecule dissociation also contributes to the initial stage of H{sub 2}O molecule loss. The role of heating of the chamber walls is discussed.

  7. Design and construct of a new detector for gas chromatography based on continuous negative corona discharge

    NASA Astrophysics Data System (ADS)

    Ghahfarokhi, M. Sharifian; Khayamian, T.

    2011-05-01

    In this work, a new detector was designed and constructed based on negative corona discharge. This detector can be used separately or as a detector in gas chromatography. The detector and chromatographic variables including cell temperature, gas flow rates, voltage between the two electrodes, and column temperature were optimized. Chloroform was used as a test compound to evaluate the performance of the detector. The detection limit of chloroform was obtained 0.78 ng/ml and its dynamic range was over the range of 2-840 ng/ml. The relative standard detection was about 6% for the limit of quantification. This detector is able to be used as an alternative for analysis of compounds containing electronegative elements.

  8. Time-resolved gas temperature evolution in pulsed Ar-N{sub 2} microwave discharge

    SciTech Connect

    Britun, Nikolay; Konstantinidis, Stephanos; Godfroid, Thomas; Snyders, Rony

    2011-04-04

    Temporal evolution of the gas temperature (T{sub g}) in a pulsed microwave surfaguide discharge is studied by measuring the N{sub 2} rotational temperature. We found that at high power applied per pulse, gas temperature grows linearly, and saturates after about 150 {mu}s. This effect is absent at low power values, or at short pulse durations. Observed T{sub g} behavior correlates with time-resolved measurements of the N{sub 2} vibrational temperature, as well as with N emission lines. Consequently, T{sub g} time behavior was related to N atoms production in plasma. Using obtained T{sub g} growth rates, the effective power used for plasma heating is determined.

  9. Loss of Ba Atom from the Electrode of Fluorescent Lamp Operating under AC and DC Discharges

    NASA Astrophysics Data System (ADS)

    Samir, Ahmed; Yamashita, Go; Egashira, Yuichi; Shimada, Shozaburo; Yamagata, Yukihiko; Uchino, Kiichiro; Manabe, Yoshio; Ueda, Takashi

    Low work function is a vital life-determining characteristic of fluorescent lamp electrodes. The work function of a fluorescent lamp electrode increases due to the loss of Ba atom from the electrode. Hence the rate of Ba atom loss controls the lifetime of the lamp. However the loss mechanism and the optimum discharge condition has not been well understood yet. In the study, the loss of Ba atom from a fluorescent lamp electrode using a laser-induced fluorescence (LIF) technique is investigated. The lamp was operated at both AC 60 Hz and DC discharge modes with different discharge currents. In addition, the electrode of fluorescent lamp was connected through an external DC current source to control the electrode temperature. The effects of both the discharge current and the electrode temperature on the emission of Ba atom were investigated. For the lamp operation at 60 Hz, the physical behavior of the emission of Ba atom from the anode and the cathode were found to be different. The most of the loss of Ba atom was observed in an anode half-cycle, while this loss was lower in a cathode half-cycle. In the case of DC discharge, with increase in the discharge current, the loss of Ba atom was increased at the anode while it was decreased at the cathode. At the cathode the decrease in temperature was due to the electron emission from the cathode, which is called as “electron cooling” and it played an important role for the suppression of the Ba atom loss. Additionally, the sputtering of Ba atom due to ion bombardment was also considered to be an important factor for the loss of Ba atom from the cathode at a low discharge current.

  10. Origin and Distribution of Thiophenes and Furans in Gas Discharges from Active Volcanoes and Geothermal Systems

    PubMed Central

    Tassi, Franco; Montegrossi, Giordano; Capecchiacci, Francesco; Vaselli, Orlando

    2010-01-01

    The composition of non-methane organic volatile compounds (VOCs) determined in 139 thermal gas discharges from 18 different geothermal and volcanic systems in Italy and Latin America, consists of C2–C20 species pertaining to the alkanes, alkenes, aromatics and O-, S- and N-bearing classes of compounds. Thiophenes and mono-aromatics, especially the methylated species, are strongly enriched in fluids emissions related to hydrothermal systems. Addition of hydrogen sulphide to dienes and electrophilic methylation involving halogenated radicals may be invoked for the formation of these species. On the contrary, the formation of furans, with the only exception of C4H8O, seems to be favoured at oxidizing conditions and relatively high temperatures, although mechanisms similar to those hypothesized for the production of thiophenes can be suggested. Such thermodynamic features are typical of fluid reservoirs feeding high-temperature thermal discharges of volcanoes characterised by strong degassing activity, which are likely affected by conspicuous contribution from a magmatic source. The composition of heteroaromatics in fluids naturally discharged from active volcanoes and geothermal areas can then be considered largely dependent on the interplay between hydrothermal vs. magmatic contributions. This implies that they can be used as useful geochemical tools to be successfully applied in both volcanic monitoring and geothermal prospection. PMID:20480029

  11. Origin and distribution of thiophenes and furans in gas discharges from active volcanoes and geothermal systems.

    PubMed

    Tassi, Franco; Montegrossi, Giordano; Capecchiacci, Francesco; Vaselli, Orlando

    2010-03-31

    The composition of non-methane organic volatile compounds (VOCs) determined in 139 thermal gas discharges from 18 different geothermal and volcanic systems in Italy and Latin America, consists of C(2)-C(20) species pertaining to the alkanes, alkenes, aromatics and O-, S- and N-bearing classes of compounds. Thiophenes and mono-aromatics, especially the methylated species, are strongly enriched in fluids emissions related to hydrothermal systems. Addition of hydrogen sulphide to dienes and electrophilic methylation involving halogenated radicals may be invoked for the formation of these species. On the contrary, the formation of furans, with the only exception of C(4)H(8)O, seems to be favoured at oxidizing conditions and relatively high temperatures, although mechanisms similar to those hypothesized for the production of thiophenes can be suggested. Such thermodynamic features are typical of fluid reservoirs feeding high-temperature thermal discharges of volcanoes characterised by strong degassing activity, which are likely affected by conspicuous contribution from a magmatic source. The composition of heteroaromatics in fluids naturally discharged from active volcanoes and geothermal areas can then be considered largely dependent on the interplay between hydrothermal vs. magmatic contributions. This implies that they can be used as useful geochemical tools to be successfully applied in both volcanic monitoring and geothermal prospection.

  12. Application of bipolar gas discharge for water sterilization from S.aureus and E-coli

    NASA Astrophysics Data System (ADS)

    Taran, Anatoliy; Okhrimovskyy, Andriy; Komozynskyi, Petro; Kyslytsyn, Oleksandr; Taran, Svitlana; Filimonova, Nataliya; Lesnoy, Viktor; Oranska, Daria

    2016-09-01

    Recently, water treatment by gas discharge above the surface of the liquid has attracted a lot of attention. In most cases, however, the unipolar power source is used. Bipolar pulses of high voltage and current can increases degree of water sterilization from organic compounds, both chemical and bacterial since non equilibrium atmospheric plasma contains not only electrons but also positive and negative ions as well as an excited molecules or atoms and active radicals. Heavy charged particles of both signs, accelerated by bipolar electric field, can easily destroy chemical and biological contaminants in water. To evaluate this phenomenon, high voltage bipolar pulse generator was used. The amplitude of the pulse voltage was approaching value of 200 kV at the discharge ignition. The repetition time was varied from 1 to 14 milliseconds. Current pulse had a shape of a superposition of bipolar pulses with decaying amplitude. Liquid surface was used as a cathode or anode.Two types of contaminants, S.aureus and E.coli, with was 1 . 5 ×108 CFU/mL were treated by bipolar high voltage pulse discharge. After 30 minutes of exposition, no contaminants were observed within the water.

  13. Full spatial-field visualization of gas temperature in an air micro-glow discharge by calibrated Schlieren photography

    NASA Astrophysics Data System (ADS)

    Xiong, Qing; Xu, Le; Wang, Xia; Xiong, Lin; Huang, Qinghua; Chen, Qiang; Wang, Jingang; Peng, Wenxiong; Li, Jiarui

    2018-03-01

    Gas temperature is an important basic parameter for both fundamental research and applications of plasmas. In this work, efforts were made to visualize the full spatial field of gas temperature (T g) in a microdischarge with sharp T g gradients by a method of calibrated Schlieren (CS) photography. Compared to other two typical diagnostic approaches, optical emission spectroscopy (OES) and Rayleigh scattering, the proposed CS method exhibits the ability to capture the whole field of gas temperature using a single Schlieren image, even the discharge is of non-luminous zones like Faraday dark space (FDS). The image shows that the T g field in the studied micro-glow air discharge expands quickly with the increase of discharge currents, especially in the cathode region. The two-dimensional maps of gas temperature display a ‘W-shape’ with sharp gradients in both areas of negative and positive glows, slightly arched distributions in the positive column, and cooling zones in the FDS. The obtained T g fields show similar patterns to that of the discharge luminance. With an increase in discharge currents, more electric energy is dissipated by heating air gas and inducing constriction of the low-temperature FDS. Except in the vicinities of electrode boundaries, due to the interference from optical diffraction, the estimated gas temperature distributions are of acceptable accuracy, confirmed by the approaches of OES and UV Rayleigh scattering.

  14. HOLLOW CARBON ARC DISCHARGE

    DOEpatents

    Luce, J.S.

    1960-10-11

    A device is described for producing an energetic, direct current, hollow, carbon-arc discharge in an evacuated container and within a strong magnetic field. Such discharges are particularly useful not only in dissociation and ionization of high energy molecular ion beams, but also in acting as a shield or barrier against the instreaming of lowenergy neutral particles into a plasma formed within the hollow discharge when it is used as a dissociating mechanism for forming the plasma. There is maintained a predetermined ratio of gas particles to carbon particles released from the arc electrodes during operation of the discharge. The carbon particles absorb some of the gas particles and are pumped along and by the discharge out of the device, with the result that smaller diffusion pumps are required than would otherwise be necessary to dispose of the excess gas.

  15. A method for achieving ignition of a low voltage gas discharge device

    DOEpatents

    Kovarik, Vincent J.; Hershcovitch, Ady; Prelec, Krsto

    1988-01-01

    An electronic device of the type wherein current flow is conducted by an ionized gas comprising a cathode of the type heated by ionic bombardment, an anode, means for maintaining a predetermined pressure in the region between the anode and the cathode and means for maintaining a field in the region. The field, which is preferably a combined magnetic and electric field, is oriented so that the mean distance traveled by electrons before reaching the anode is increased. Because of this increased distance traveled electrons moving to the anode will ionize a larger number of gas atoms, thus reducing the voltage necesary to initiate gas breakdown. In a preferred embodiment the anode is a main hollow cathode and the cathode is a smaller igniter hollow cathode located within and coaxial with the main hollow cathode. An axial magnetic field is provided in the region between the hollow cathodes in order to facilitate gas breakdown in that region and initiate plasma discharge from the main hollow cathode.

  16. Synergetic aspects of gas-discharge: lateral patterns in dc systems with a high ohmic barrier

    NASA Astrophysics Data System (ADS)

    Purwins, H.-G.; Stollenwerk, L.

    2014-12-01

    The understanding of self-organized patterns in spatially extended nonlinear dissipative systems is one of the most challenging subjects in modern natural sciences. Such patterns are also referred to as dissipative structures. We review this phenomenon in planar low temperature dc gas-discharge devices with a high ohmic barrier. It is demonstrated that for these systems a deep qualitative understanding of dissipative structures can be obtained from the point of view of synergetics. At the same time, a major contribution can be made to the general understanding of dissipative structures. The discharge spaces of the experimentally investigated systems, to good approximation, have translational and rotational symmetry by contraction. Nevertheless, a given system may exhibit stable current density distributions and related patterns that break these symmetries. Among the experimentally observed fundamental patterns one finds homogeneous isotropic states, fronts, periodic patterns, labyrinth structures, rotating spirals, target patterns and localized filaments. In addition, structures are observed that have the former as elementary building blocks. Finally, defect structures as well as irregular patterns are common phenomena. Such structures have been detected in numerous other driven nonlinear dissipative systems, as there are ac gas-discharge devices, semiconductors, chemical solutions, electrical networks and biological systems. Therefore, from the experimental observations it is concluded that the patterns in planar low temperature dc gas-discharge devices exhibit universal behavior. From the theoretical point of view, dissipative structures of the aforementioned kind are also referred to as attractors. The possible sets of attractors are an important characteristic of the system. The number and/or qualitative nature of attractors may change when changing parameters. The related bifurcation behavior is a central issue of the synergetic approach chosen in the present

  17. Studies on gas breakdown in pulsed radio frequency atmospheric pressure glow discharges

    SciTech Connect

    Huo, W. G.; School of Physics and Electronic Technology, Liaoning Normal University, Dalian 116029; Jian, S. J.

    2014-05-15

    In pulsed RF atmospheric pressure glow discharges, the gas breakdown judged by the rapid drop in the amplitude of the pulsed RF voltage is no longer universally true. The steep increment of the plasma-absorbed RF power is proposed to determine the gas breakdown. The averaged plasma-absorbed RF power over a pulse period is used to evaluate effects of the preceding pulsed RF discharge on the breakdown voltage of the following one, finding that the breakdown voltage decreases with the increment in the averaged plasma-absorbed RF power under constant pulse duty ratio. Effects of the pulse off-time on the breakdown voltagemore » and the breakdown delay time are also studied. The obtained dependence of the breakdown voltage on the pulse off-time is indicative of the transitional plasma diffusion processes in the afterglow. The breakdown voltage varies rapidly as the plasma diffuses fast in the region of moderate pulse off-time. The contribution of nitrogen atom recombination at the alumina surface is demonstrated in the prolonged memory effect on the breakdown delay time vs. the pulse off-time and experimentally validated by introducing a trace amount of nitrogen into argon at short and long pulse off-times.« less

  18. Dust trap formation in a non-self-sustained discharge with external gas ionization

    SciTech Connect

    Filippov, A. V., E-mail: fav@triniti.ru; Babichev, V. N.; Pal’, A. F.

    2015-11-15

    Results from numerical studies of a non-self-sustained gas discharge containing micrometer dust grains are presented. The non-self-sustained discharge (NSSD) was controlled by a stationary fast electron beam. The numerical model of an NSSD is based on the diffusion drift approximation for electrons and ions and self-consistently takes into account the influence of the dust component on the electron and ion densities. The dust component is described by the balance equation for the number of dust grains and the equation of motion for dust grains with allowance for the Stokes force, gravity force, and electric force in the cathode sheath. Themore » interaction between dust grains is described in the self-consistent field approximation. The height of dust grain levitation over the cathode is determined and compared with experimental results. It is established that, at a given gas ionization rate and given applied voltage, there is a critical dust grain size above which the levitation condition in the cathode sheath cannot be satisfied. Simulations performed for the dust component consisting of dust grains of two different sizes shows that such grains levitate at different heights, i.e., size separation of dust drains levitating in the cathode sheath of an NSSD takes place.« less

  19. Axial mercury vapour pressure distributions in DC operated low pressure mercury argon discharges

    NASA Astrophysics Data System (ADS)

    Gielen, John; de Groot, Simon; van Dijk, Jan; van der Mullen, Joost

    2000-10-01

    In a steady state DC operated (cylindrical) low pressure mercury argon discharge, an electric field exists in axial direction which results in a non-uniform axial mercury vapour pressure distribution; this phenomenon is termed cataphoresis. In a discharge tube covered with a fluorescent powder this gives in a non-uniform axial light distribution. Towards lighting applications this is a potential disadvantage, which is not present in AC operated fluorescent lamps. The dependence of the axial mercury vapour pressure distribution under DC operation on discharge tube and discharge parameters has been investigated. A model has been developed to predict the axial mercury vapour pressure distribution, in which the balance equations for particle and momentum conservation are solved in combination with a plasma physical model, and experiments have been performed to validate the model. In the present contribution the model and experimental results will be discussed and it will be demonstrated that the applied theoretical approach provides a better description of the axial mercury vapour pressure distribution compared to previous models known from literature.

  20. Optical and application study of gas-liquid discharge excited by bipolar nanosecond pulse in atmospheric air

    NASA Astrophysics Data System (ADS)

    Wang, Sen; Wang, Wen-chun; Yang, De-zheng; Liu, Zhi-jie; Zhang, Shuai

    2014-10-01

    In this study, a bipolar nanosecond pulse with 20 ns rising time is employed to generate air gas-liquid diffuse discharge plasma with room gas temperature in quartz tube at atmospheric pressure. The image of the discharge and optical emission spectra of active species in the plasma are recorded. The plasma gas temperature is determined to be approximately 390 K by compared the experimental spectra with the simulated spectra, which is slightly higher than the room temperature. The result indicated that the gas temperature rises gradually with pulse peak voltage increasing, while decreases slightly with the electrode gap distance increasing. As an important application, bipolar nanosecond pulse discharge is used to sterilize the common microorganisms (Actinomycetes, Candida albicans and Escherichia coli) existing in drinking water, which performs high sterilization efficiency.

  1. Effects of gas temperature on NO(x) removal by dielectric barrier discharge.

    PubMed

    Wang, Tao; Sun, Bao-Min; Xiao, Hai-Ping

    2013-01-01

    The purpose of this investigation is to discuss the effect of gas temperature on NO(x) removal by dielectric barrier discharge. The Boltzmann equation was used to analyse the electron distribution function in the reactor, and experiments were conducted to find out the effects of different temperatures. The calculation results show that, with a rise in the temperature, E/N increases, increasing the ionization rate. When the ratio of electric field strength to total gas density (E/N) rises from 50 to 150 Td, the ionization rate and electron mean energy increase by 2.0 x 10(5) and 2.3, respectively. The experiments show that in the NO/N2 system, when the temperature increases to 1 30 degrees C and the applied voltage is 11.1 kV, the discharge power is 44.7 W, which is higher than the discharge power of 35.4 W found at 25 degrees C; in the NO/O2/N2 system, an increase in the temperature increases the decomposition of active O3 species, producing a negative effect on NO oxidation; in the NO/O2/N2/C2H4 system, when the temperature increases, the quantity of active species HO2 increases and the NO removal reaction rate increases, reflecting an obvious improvement in the NO removal; and in the NO/O2/N2/C2H4/H2O system, at 25 degrees C, 90 degrees C, and 130 degrees C, when the energy density is 239.7 J L(-1), the NO removal efficiencies are 52.8%, 66.4%, and 71.0%, respectively.

  2. Carbon dioxide laser with an e-beam-initiated discharge produced in the working gas mixture at a pressure up to 5 atm

    SciTech Connect

    Orlovskii, Viktor M; Alekseev, S B; Tarasenko, Viktor F

    2011-11-30

    A high-pressure CO{sub 2} laser with a discharge initiated by an electron beam of sub-nanosecond duration in the laser gas mixture at a pressure up to 5 atm is fabricated. For the 20-ns pulses the energy from the active volume {approx} 4 cm{sup 3} amounted to 40 mJ. The laser operation at a pulse repetition rate up to 5 Hz is demonstrated. In the gas mixture CO{sub 2}:N{sub 2}:He = 1:1:6 at a pressure 5 atm, the specific energy deposition of {approx} 0.07 J cm{sup -3} atm{sup -1} is obtained in the process of a non-self-sustained discharge with ionisation amplification.

  3. Algebraic operator approach to gas kinetic models

    NASA Astrophysics Data System (ADS)

    Il'ichov, L. V.

    1997-02-01

    Some general properties of the linear Boltzmann kinetic equation are used to present it in the form ∂ tϕ = - †Âϕ with the operators Âand† possessing some nontrivial algebraic properties. When applied to the Keilson-Storer kinetic model, this method gives an example of quantum ( q-deformed) Lie algebra. This approach provides also a natural generalization of the “kangaroo model”.

  4. Operation of the J-series thruster using inert gas

    NASA Technical Reports Server (NTRS)

    Rawlin, V. K.

    1982-01-01

    Electron bombardment ion thrusters using inert gases are candidates for large space systems. The J-Series 30 cm diameter thruster, designed for operation up to 3 k-W with mercury, is at a state of technology readiness. The characteristics of operation with xenon, krypton, and argon propellants in a J-Series thruster with that obtained with mercury are compared. The performance of the discharge chamber, ion optics, and neutralizer and the overall efficiency as functions of input power and specific impulse and thruster lifetime were evaluated. As expected, the discharge chamber performance with inert gases decreased with decreasing atomic mass. Aspects of the J-Series thruster design which would require modification to provide operation at high power with insert gases were identified.

  5. FUEL CELL OPERATION ON LANDFILL GAS AT PENROSE POWER STATION

    EPA Science Inventory

    This demonstration test successfully demonstrated operation of a commercial phosphoric acid fuel cell (FC) on landfill gas (LG) at the Penrose Power Station in Sun Valley, CA. Demonstration output included operation up to 137 kW; 37.1% efficiency at 120 kW; exceptionally low sec...

  6. Subthreshold self-sustained discharge initiated by a microwave beam in a large volume of high-pressure gas

    NASA Astrophysics Data System (ADS)

    Artem’ev, K. V.; Batanov, G. M.; Berezhetskaya, N. K.; Davydov, A. M.; Kossyi, I. A.; Nefedov, V. I.; Sarksyan, K. A.; Kharchev, N. K.

    2017-10-01

    The presented results are based on the experimental studies of generating a long plasma column in gas (or gas mixtures) at atmospheric pressure both in free space and in a closed chamber. The microwave generator GYROTRON was used as an energy source. Its parameters were as follows: the microwave pulse power was in the range of 200 ≤ P ≤ 600 kW, the wavelength was λ ≈ 0.4 cm, and the pulse duration was in the range of 0.5 ≤ τi ≤ 20 ms. Under strong subthreshold conditions, a plasma column with a length of up to L ≤ 50 cm was created using a microwave beam that was formed using a quasi-optical mirror system. The discharge initiation system had an original design. Based on the discharge structure, expansion dynamics and typical discharge plasma parameters, this discharge can be attributed to the type of microwave discharges that are known as self/non-self-sustained discharges. The discharge properties and advantages of using this discharge as a basis of a plasma-chemical reactor are discussed.

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

    SciTech Connect

    Kongpiboolkid, Watcharapon; Mongkolnavin, Rattachat; Plasma Technology and Nuclear Fusion Research Unit, Chulalongkorn University, Bangkok

    2015-04-24

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

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

    SciTech Connect

    Kongpiboolkid, Watcharapon; Mongkolnavin, Rattachat

    2015-04-24

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

  9. 46 CFR 153.1130 - Failure of slops discharge recording equipment; operating with, reporting failures, and replacing...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Failure of slops discharge recording equipment; operating with, reporting failures, and replacing pollution equipment: Category A, B, C, D. 153.1130 Section... slops discharge recording equipment; operating with, reporting failures, and replacing pollution...

  10. 46 CFR 153.1130 - Failure of slops discharge recording equipment; operating with, reporting failures, and replacing...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Failure of slops discharge recording equipment; operating with, reporting failures, and replacing pollution equipment: Category A, B, C, D. 153.1130 Section... slops discharge recording equipment; operating with, reporting failures, and replacing pollution...

  11. 46 CFR 153.1130 - Failure of slops discharge recording equipment; operating with, reporting failures, and replacing...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Failure of slops discharge recording equipment; operating with, reporting failures, and replacing pollution equipment: Category A, B, C, D. 153.1130 Section... slops discharge recording equipment; operating with, reporting failures, and replacing pollution...

  12. 46 CFR 153.1130 - Failure of slops discharge recording equipment; operating with, reporting failures, and replacing...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Failure of slops discharge recording equipment; operating with, reporting failures, and replacing pollution equipment: Category A, B, C, D. 153.1130 Section... slops discharge recording equipment; operating with, reporting failures, and replacing pollution...

  13. 46 CFR 153.1130 - Failure of slops discharge recording equipment; operating with, reporting failures, and replacing...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Failure of slops discharge recording equipment; operating with, reporting failures, and replacing pollution equipment: Category A, B, C, D. 153.1130 Section... slops discharge recording equipment; operating with, reporting failures, and replacing pollution...

  14. Optimization of wastewater treatment plant operation for greenhouse gas mitigation.

    PubMed

    Kim, Dongwook; Bowen, James D; Ozelkan, Ertunga C

    2015-11-01

    This study deals with the determination of optimal operation of a wastewater treatment system for minimizing greenhouse gas emissions, operating costs, and pollution loads in the effluent. To do this, an integrated performance index that includes three objectives was established to assess system performance. The ASMN_G model was used to perform system optimization aimed at determining a set of operational parameters that can satisfy three different objectives. The complex nonlinear optimization problem was simulated using the Nelder-Mead Simplex optimization algorithm. A sensitivity analysis was performed to identify influential operational parameters on system performance. The results obtained from the optimization simulations for six scenarios demonstrated that there are apparent trade-offs among the three conflicting objectives. The best optimized system simultaneously reduced greenhouse gas emissions by 31%, reduced operating cost by 11%, and improved effluent quality by 2% compared to the base case operation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. NPDES permit compliance and enforcement: A resource guide for oil and gas operators

    SciTech Connect

    1998-12-01

    During the fall of 1996, the Interstate Oil and Gas Compact Commission sponsored sessions for government and industry representatives to discuss concerns about the National Pollution Discharge Elimination System (NPDES) program under the Clean Water Act. In January 1997, the NPDES Education/Communication/Training Workgroup (ECT Workgroup) was established with co-leaders from the Environmental Protection Agency (EPA) and industry. The ECT Workgroup`s purpose was to develop ideas that would improve communication between NPDES regulators and the oil and gas industry regarding NPDES compliance issues. The Workgroup focused on several areas, including permit compliance monitoring and reporting, enforcement activity and options, and treatment technology. The ECT Workgroup also discussed the need for materials and information to help NPDES regulatory agency personnel understand more about oil and gas industry exploration and extraction operations and treatment processes. This report represents a compendium of the ECT Workgroup`s efforts.

  16. Operating Experience Review of the INL HTE Gas Monitoring System

    SciTech Connect

    L. C. Cadwallader; K. G. DeWall

    2010-06-01

    This paper describes the operations of several types of gas monitors in use at the Idaho National Laboratory (INL) High Temperature Electrolysis Experiment (HTE) laboratory. The gases monitored at hydrogen, carbon monoxide, carbon dioxide, and oxygen. The operating time, calibration, and unwanted alarms are described. The calibration session time durations are described. Some simple statistics are given for the reliability of these monitors and the results are compared to operating experiences of other types of monitors.

  17. Autonomous portable pulsed-periodical generator of high-power radiofrequency-pulses based on gas discharge with hollow cathode.

    PubMed

    Bulychev, Sergey V; Dubinov, Alexander E; L'vov, Igor L; Popolev, Vyacheslav L; Sadovoy, Sergey A; Sadchikov, Eugeny A; Selemir, Victor D; Valiulina, Valeria K; Vyalykh, Dmitry V; Zhdanov, Victor S

    2016-05-01

    Portable autonomous generator of high-power RF-pulses based on the gas discharge with hollow cathode has been designed, fabricated, and tested. Input and output characteristics are the following: discharge current amplitude is 800 A, duration of generated RF-pulses is 350 ns, carrier frequency is ∼90 MHz, power in RF-pulse is 0.5 MW, pulse repetition rate is 0.5 kHz, and device efficiency is ∼25%.

  18. Compact soft x-ray microscope using a gas-discharge light source.

    PubMed

    Benk, Markus; Bergmann, Klaus; Schäfer, David; Wilhein, Thomas

    2008-10-15

    We report on a soft x-ray microscope using a gas-discharge plasma with pseudo spark-like electrode geometry as a light source. The source produces a radiant intensity of 4 x 10(13) photons/(sr pulse) for the 2.88 nm emission line of helium-like nitrogen. At a demonstrated 1 kHz repetition rate a brilliance of 4.3 x 10(9) photons/(microm2 sr s) is obtained for the 2.88 nm line. Ray-tracing simulations show that, employing an adequate grazing incidence collector, a photon flux of 1 x 10(7) photons/(microm2 s) can be achieved with the current source. The applicability of the presented pinch plasma concept to soft x-ray microscopy is demonstrated in a proof-of-principle experiment.

  19. Impacts from oil and gas produced water discharges on the gulf of Mexico hypoxic zone.

    SciTech Connect

    Parker, M. E.; Satterlee, K.; Veil, J. A.; Environmental Science Division; ExxonMobil Production Co.; Shell Offshore

    2006-01-01

    Shallow water areas of the Gulf of Mexico continental shelf experience low dissolved oxygen (hypoxia) each summer. The hypoxic zone is primarily caused by input of nutrients from the Mississippi and Atchafalaya Rivers. The nutrients stimulate the growth of phytoplankton, which leads to reduction of the oxygen concentration near the sea floor. During the renewal of an offshore discharge permit used by the oil and gas industry in the Gulf of Mexico, the U.S. Environmental Protection Agency (EPA) identified the need to assess the potential contribution from produced water discharges to the occurrence of hypoxia. The EPA permit required either that all platforms in the hypoxic zone submit produced water samples, or that industry perform a coordinated sampling program. This paper, based on a report submitted to EPA in August 2005 (1), describes the results of the joint industry sampling program and the use of those results to quantify the relative significance of produced water discharges in the context of other sources on the occurrence of hypoxia in the Gulf of Mexico. In the sampling program, 16 facilities were selected for multiple sampling - three times each at one month intervals-- and another 34 sites for onetime sampling. The goal of the sampling program was to quantify the sources and amount of oxygen demand associated with a variety of Gulf of Mexico produced waters. Data collected included direct oxygen demand measured by BOD5 (5-day biochemical oxygen demand) and TOC (total organic carbon) and indirect oxygen demand measured by nitrogen compounds (ammonia, nitrate, nitrate, and TKN [total Kjeldahl nitrogen]) and phosphorus (total phosphorus and orthophosphate). These data will serve as inputs to several available computer models currently in use for forecasting the occurrence of hypoxia in the Gulf of Mexico. The output of each model will be compared for consistency in their predictions and then a semi-quantitative estimate of the relative significance of

  20. Characteristics of gas-liquid pulsed discharge plasma reactor and dye decoloration efficiency.

    PubMed

    Sun, Bing; Aye, Nyein Nyein; Gao, Zhiying; Lv, Dan; Zhu, Xiaomei; Sato, Masayuki

    2012-01-01

    The pulsed high-voltage discharge is a new advanced oxidation technology for water treatment. Methyl Orange (MO) dye wastewater was chosen as the target object. Some investigations were conducted on MO decoloration including the discharge characteristics of the multi-needle reactor, parameter optimization, and the degradation mechanism. The following results were obtained. The color group of the azo dye MO was effectively decomposed by water surface plasma. The decoloration rate was promoted with the increase of treatment time, peak voltage, and pulse frequency. When the initial conductivity was 1700 microS/cm, the decoloration rate was the highest. The optimum distance between the needle electrodes and the water surface was 1 mm, the distance between the grounding electrode and the water surface was 28 mm, and the number of needle electrodes and spacing between needles were 24 and 7.5 mm, respectively. The decoloration rate of MO was affected by the gas in the reactor and varied in the order oxygen > air> argon > nitrogen, and the energy yield obtained in this investigation was 0.45 g/kWh.

  1. Zero Liquid Discharge (ZLD) System for Flue-Gas Derived Water From Oxy-Combustion Process

    SciTech Connect

    Sivaram Harendra; Danylo Oryshchyn; Thomas Ochs

    2011-10-16

    Researchers at the National Energy Technology Laboratory (NETL) located in Albany, Oregon, have patented a process - Integrated Pollutant Removal (IPR) that uses off-the-shelf technology to produce a sequestration ready CO{sub 2} stream from an oxy-combustion power plant. Capturing CO{sub 2} from fossil-fuel combustion generates a significant water product which can be tapped for use in the power plant and its peripherals. Water condensed in the IPR{reg_sign} process may contain fly ash particles, sodium (from pH control), and sulfur species, as well as heavy metals, cations and anions. NETL is developing a treatment approach for zero liquid discharge while maximizingmore » available heat from IPR. Current treatment-process steps being studied are flocculation/coagulation, for removal of cations and fine particles, and reverse osmosis, for anion removal as well as for scavenging the remaining cations. After reverse osmosis process steps, thermal evaporation and crystallization steps will be carried out in order to build the whole zero liquid discharge (ZLD) system for flue-gas condensed wastewater. Gypsum is the major product from crystallization process. Fast, in-line treatment of water for re-use in IPR seems to be one practical step for minimizing water treatment requirements for CO{sub 2} capture. The results obtained from above experiments are being used to build water treatment models.« less

  2. Zero Liquid Discharge (ZLD) System for Flue-Gas Derived Water From Oxy-Combustion Process

    SciTech Connect

    Sivaram Harendra; Danylo Oryshchyn; Thomas Ochs; Stephen J. Gerdemann; John Clark

    2011-10-16

    Researchers at the National Energy Technology Laboratory (NETL) located in Albany, Oregon, have patented a process - Integrated Pollutant Removal (IPR) that uses off-the-shelf technology to produce a sequestration ready CO{sub 2} stream from an oxy-combustion power plant. Capturing CO{sub 2} from fossil-fuel combustion generates a significant water product which can be tapped for use in the power plant and its peripherals. Water condensed in the IPR{reg_sign} process may contain fly ash particles, sodium (from pH control), and sulfur species, as well as heavy metals, cations and anions. NETL is developing a treatment approach for zero liquid discharge while maximizing available heat from IPR. Current treatment-process steps being studied are flocculation/coagulation, for removal of cations and fine particles, and reverse osmosis, for anion removal as well as for scavenging the remaining cations. After reverse osmosis process steps, thermal evaporation and crystallization steps will be carried out in order to build the whole zero liquid discharge (ZLD) system for flue-gas condensed wastewater. Gypsum is the major product from crystallization process. Fast, in-line treatment of water for re-use in IPR seems to be one practical step for minimizing water treatment requirements for CO{sub 2} capture. The results obtained from above experiments are being used to build water treatment models.

  3. Worcester 1 Inch Solenoid Actuated Gas Operated SCHe System Valves

    SciTech Connect

    MISKA, C.R.

    2000-09-03

    1 inch gas-operated full-port ball valves incorporate a solenoid and limit switches as integral parts of the actuator. These valves are normally open and fail safe to the open position (GOV-1*02 and 1*06 fail closed) to provide a flow path of helium gas to the MCO under helium purge and off-normal conditions when the MCO is isolated.

  4. Worcester 1 Inch Solenoid Actuated Gas Operated SCHe System Valves

    SciTech Connect

    VAN KATWIJK, C.

    2000-10-23

    1 inch Gas-operated full-port ball valves incorporate a solenoid and limit switches as integral parts of the actuator. These valves are normally open and fail safe to the open position (GOV-1*02 and 1*06 fall closed) to provide a flow path of helium gas to the MCO under helium purge and off-normal conditions when the MCO is isolated.

  5. Worcester 1 Inch Solenoid Actuated Gas Operated SCHe System Valves

    SciTech Connect

    MISKA, C.R.

    2000-11-13

    1 inch gas-operated full-port ball valves incorporate a solenoid and limit switches as integral parts of the actuator. These valves are normally open and fail safe to the open position (GOV-1*02 and 1*06 fail closed) to provide a flow path of helium gas to the MCO under helium purge and off-normal conditions when the MCO is isolated.

  6. Worcester 1 Inch Solenoid Actuated Gas Operated SCHe System Valves

    SciTech Connect

    VAN KATWIJK, C.

    2000-06-06

    1 inch Gas-operated full-port ball valves incorporate a solenoid and limit switches as integral parts of the actuator. These valves are normally open and fail safe to the open position (GOV-1*02 and 1*06 fail closed) to provide a flow path of helium gas to the MCO under helium purge and off-normal conditions when the MCO is isolated.

  7. Gas Breakdown, Low Current diffuse discharges, Townsend's theory: A Friday afternoon experiment

    NASA Astrophysics Data System (ADS)

    Petrovic, Zoran

    2013-09-01

    Numerous aspects of the ``standard model'' of gas breakdown have been addressed in the past 20 years by Art Phelps and his coworkers. First, his studies of excitation coefficients were carried out in the Townsend regime where electric field is quasi uniform so swarm like conditions prevail. These studies have been extended to very high E/N where non-hydrodynamic effects were to be observed but were overshadowed in most cases by fast neutral excitation. Absolute calibration of emission provided a basis to obtain fast neutral cross section sets. This work necessarily overlapped with the left hand side of the Paschen curve and in extension of an ill fated data gathering experiment a review was made of all the processes that contribute to the secondary electron emission. It was shown that, if one includes all the processes, it is possible to fit the available breakdown data, Paschen curves and effective electron yields by binary collision data obtained in separate experiments. While performing measurements in the low current diffuse (Townsend) regime one can find negative differential resistance and oscillations. Both were explained by taking detailed information on properties of particles close to the cathode and small perturbations to the local field by the growing space charge. Last but not the least Phelps managed, with his coworkers to provide a phenomenology and predictions of the anomalously broadened profiles often observed in various discharges. In all those cases deep knowledge of atomic and molecular physics and of gas discharges were combined with best available data to produce quantitative (quantitative, quantitative) agreement with experiments. Coworkers: Dragana Maric. Supported by MPNTR project ON171037 and SANU project 155.

  8. Research targets lower gas-processing operating costs

    SciTech Connect

    Meyer, H.S.; Leppin, D.

    1997-12-29

    Increasing natural-gas demand and declining gas quality at the wellhead require the gas-processing industry to look to new technologies to stay competitive. The Gas Research Institute (GRI), Chicago, is managing a research, development, design, and deployment program that could save industry $230 million/year in operating and capital costs from NGL extraction and recovery, dehydration, acid-gas removal/sulfur recovery, and nitrogen rejection. Three technologies are addressed here. (1) Multivariable control (MVC) technology for predictive process control and optimization is installed or in design at 14 facilities, treating a combined total of more than 30 billion normal cu m/year (bcmy; 1.1 trillion standardmore » cu ft/year, tcfy). Simple paybacks are typically less than 6 months. (2) A new acid-gas-removal process based on N-formyl morpholine (NFM) is being field tested that offers 40--50% savings in operating costs and 15--30% savings in capital costs relative to a commercially available physical solvent. (3) The GRI-MemCalc computer program for membrane separations and the GRI-Scavenger CalcBase computer program for scavenging technologies are screening tools that engineers can use to determine the best practice for treating their gas.« less

  9. Radio Frequency Underwater Discharge Operation and Its Application to Congo Red Degradation

    NASA Astrophysics Data System (ADS)

    Ji, Liangliang; Zou, Shuai; Shen, Mingrong; Xin, Yu

    2012-02-01

    Radio frequency (RF) underwater discharge operation was performed for different liquid conductivities driven by different frequencies ranging from 13.56 MHz to 60 MHz, and its application to organic degradation was investigated. The RF underwater discharge was observed to be generated within the bubble at electrode surface formed by RF and plasma heating. It was shown that the sizes of the bubbles and plasmas increased as the driving frequency and the input power went up. The breakdown voltage decreased rapidly with the increase of the water conductivity and driving frequency. Comparative experiments of the UV-VIS absorbance spectra of Congo Red solution before and after discharge suggested effective degradation of the organic dye due to the active species generated during the discharge, such as ·OH, ·O, ·H, etc. revealed by optical emission spectroscopy. The results show that higher exciting frequency and lower conductivity of the solution are more effective for organic degradation. With the combination of Fourier Transform Infrared Spectroscopy (FT-IR) and Liquid Chromatography-Mass Spectrometry (LC-MS) data, one possible degradation process was proposed and the main conceivable components and structures of the products were also presented.

  10. Gas Hydrate Research Coring and Downhole Logging Operational Protocol

    NASA Astrophysics Data System (ADS)

    Collett, T. S.; Riedel, M.; Malone, M.

    2006-12-01

    Recent gas hydrate deep coring and downhole logging projects, including ODP Leg 204, IODP Expedition 311, and the India NGHP-01 effort have contributed greatly to our understanding of the geologic controls on the occurrence of gas hydrate. These projects have also built on the relatively sparse history of gas hydrate drilling experience to collectively develop a unique operational protocol to examine and sample gas hydrate in nature. The ideal gas hydrate research drill site in recent history, consists of at least three drill holes, with the first hole dedicated to LWD/MWD downhole logging in order to identify intervals to be pressurized cored and to collect critical petrophysical data. The second hole is usually dedicated for continuous coring operations. The third hole is used for special downhole tool measurements such as pressure coring and wire line logging. There is a strong scientific need to obtain LWD/MWD data prior to coring. The coring operations are complemented by frequent deployment of the PCS/HYACINTH pressure core systems. It is essential to know what the gas hydrate concentrations and vertical distribution are before deploying the available pressure core systems in order to choose the optimum depths for pressure coring operations. The coring operations are also complemented by frequent sampling for interstitial water, headspace gas, and microbiological analyses. Although those samples will be taken at relatively regular depths, the sampling frequency can be adjusted if gas hydrate concentrations and distribution can be forward predicted through the analysis of the LWD/MWD pre-core logging surveys. After completing the LWD/MWD logging program, usually as a dedicated drilling leg, field efforts will switch to conventional and pressure-controlled coring operations at each of the sites drilled during the LWD/MWD campaign. The standard continuous core hole will usually include APC coring to an expected refusal depth of ~100 mbsf; each hole is usually

  11. The Effects of Added Hydrogen on Noble Gas Discharges Used as Ambient Desorption/Ionization Sources for Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Ellis, Wade C.; Lewis, Charlotte R.; Openshaw, Anna P.; Farnsworth, Paul B.

    2016-09-01

    We demonstrate the effectiveness of using hydrogen-doped argon as the support gas for the dielectric barrier discharge (DBD) ambient desorption/ionization (ADI) source in mass spectrometry. Also, we explore the chemistry responsible for the signal enhancement observed when using both hydrogen-doped argon and hydrogen-doped helium. The hydrogen-doped argon was tested for five analytes representing different classes of molecules. Addition of hydrogen to the argon plasma gas enhanced signals for gas-phase analytes and for analytes coated onto glass slides in positive and negative ion mode. The enhancements ranged from factors of 4 to 5 for gas-phase analytes and factors of 2 to 40 for coated slides. There was no significant increase in the background. The limit of detection for caffeine was lowered by a factor of 79 using H2/Ar and 2 using H2/He. Results are shown that help explain the fundamental differences between the pure-gas discharges and those that are hydrogen-doped for both argon and helium. Experiments with different discharge geometries and grounding schemes indicate that observed signal enhancements are strongly dependent on discharge configuration.

  12. Study of carbon dioxide gas treatment based on equations of kinetics in plasma discharge reactor

    NASA Astrophysics Data System (ADS)

    Abedi-Varaki, Mehdi

    2017-08-01

    Carbon dioxide (CO2) as the primary greenhouse gas, is the main pollutant that is warming earth. CO2 is widely emitted through the cars, planes, power plants and other human activities that involve the burning of fossil fuels (coal, natural gas and oil). Thus, there is a need to develop some method to reduce CO2 emission. To this end, this study investigates the behavior of CO2 in dielectric barrier discharge (DBD) plasma reactor. The behavior of different species and their reaction rates are studied using a zero-dimensional model based on equations of kinetics inside plasma reactor. The results show that the plasma reactor has an effective reduction on the CO2 density inside the reactor. As a result of reduction in the temporal variations of reaction rate, the speed of chemical reactions for CO2 decreases and very low concentration of CO2 molecules inside the plasma reactor is generated. The obtained results are compared with the existing experimental and simulation findings in the literature.

  13. Description and initial operating performance of the Langley 6-inch expansion tube using heated helium driver gas

    NASA Technical Reports Server (NTRS)

    Moore, J. A.

    1975-01-01

    A general description of the Langley 6-inch expansion tube is presented along with discussion of the basic components, internal resistance heater, arc-discharge assemblies, instrumentation, and operating procedure. Preliminary results using unheated and resistance-heated helium as the driver gas are presented. The driver-gas pressure ranged from approximately 17 to 59 MPa and its temperature ranged from 300 to 510 K. Interface velocities of approximately 3.8 to 6.7 km/sec were generated between the test gas and the acceleration gas using air as the test gas and helium as the acceleration gas. Test flow quality and comparison of measured and predicted expansion-tube flow quantities are discussed.

  14. Operation and planning of coordinated natural gas and electricity infrastructures

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaping

    Natural gas is becoming rapidly the optimal choice for fueling new generating units in electric power system driven by abundant natural gas supplies and environmental regulations that are expected to cause coal-fired generation retirements. The growing reliance on natural gas as a dominant fuel for electricity generation throughout North America has brought the interaction between the natural gas and power grids into sharp focus. The primary concern and motivation of this research is to address the emerging interdependency issues faced by the electric power and natural gas industry. This thesis provides a comprehensive analysis of the interactions between the two systems regarding the short-term operation and long-term infrastructure planning. Natural gas and renewable energy appear complementary in many respects regarding fuel price and availability, environmental impact, resource distribution and dispatchability. In addition, demand response has also held the promise of making a significant contribution to enhance system operations by providing incentives to customers for a more flat load profile. We investigated the coordination between natural gas-fired generation and prevailing nontraditional resources including renewable energy, demand response so as to provide economical options for optimizing the short-term scheduling with the intense natural gas delivery constraints. As the amount and dispatch of gas-fired generation increases, the long-term interdependency issue is whether there is adequate pipeline capacity to provide sufficient gas to natural gas-fired generation during the entire planning horizon while it is widely used outside the power sector. This thesis developed a co-optimization planning model by incorporating the natural gas transportation system into the multi-year resource and transmission system planning problem. This consideration would provide a more comprehensive decision for the investment and accurate assessment for system adequacy and

  15. Effect of Oxygen Gas on the Decomposition of Dye by Pulsed Discharge in Water Droplet Spray

    NASA Astrophysics Data System (ADS)

    Nose, Taisuke; Yokoyama, Yuzo; Nakamura, Akira; Minamitani, Yasushi

    Effect of O2 on the decolorization of indigo carmine and on the production of dissolved species such as NO2-, NO3-, O3 and H2O2 in the treatment water by pulsed discharge in water droplet spray was investigated by controlling the O2/N2 ratios as carrier gases in the reactor. The decolorization rate gradually increased with rise in O2 ratio, which reached a constant value in the range of 50% to 90% O2 ratio and decreased in pure O2. The maximum value was about 2 times as high as that of 20% O2 ratio. The decolorization efficiency was not affected by gas flow rate in the range of 4 L/min to 50 L/min. NO2- in the treatment water was only detected in pure N2, but NO3- was produced in O2/N2. NO2- added to the treatment water was not oxidized in pure N2, but was perfectly converted to NO3- in O2/N2. These results implied that hydroxyl radical produced in gas phase does not directly contribute to the oxidation of substances in water. O3 concentration gradually increased with rise in O2 ratio, whereas H2O2 concentration decreased. In the range of 50 to 80% O2 ratio, O3 and H2O2 concentrations were approximately constant value, similar to the trend of decolorization rate. Moreover rate constants on various gas mixing ratio of O2/N2 were determined from the kinetics study. These results suggested that hydroxyl radical produced in the treatment water by the chain reactions of O3 and hydroperoxy radical (HO2·) plays an important role of the decomposition of molecules in water.

  16. Investigation of a two-electrode gas switch with electrodynamical acceleration of spark channel in oscillatory regime of discharge

    NASA Astrophysics Data System (ADS)

    Kharlov, A. V.; Kovalchuk, B. M.; Kumpyak, E. V.; Tsoy, N. V.

    2017-10-01

    We have developed a compact gas switch intended for operation in oscillatory (low damping) regime of discharge. It is two-electrode switch with electrodynamic acceleration of a spark channel and a matched series injection trigger generator. A series inductance is employed for isolation of a trigger pulse from a surrounded circuit. Two operations regimes have been investigated, namely "fast" regime with current amplitude ~ 160 kA, total charge ~ 12 C, period of oscillations 60 μ s, full pulse length ~ 400 μ s and "slow" regime with current amplitude ~ 30 kA, total charge 18 C, period of oscillations 360 μ s, full pulse length ~ 3 ms. The spark gap can be triggered reliably from 16 to 50 kV (at 72 kV self-breakdown voltage). Time delay in firing was less than 35 ns at 1 ns jitter at 30 mm gap and 40 kV charging voltage. The spark gap is designed for 50 kV charging voltage, at a current up to 200 kA, and up to 20 C charge transfer. Arc motion and electrodes erosion in this spark gap have been investigated. The main results are as follows: the arc channel moves on ~ 18 cm in fast regime and ~ 25 cm in slow regime. Results of the switch operation in slow and fast regimes with operational voltage of 40 kV and stored energy 32 kJ promise to get high lifetime. In this paper we present design for the spark gap and trigger generator. Test bed schematics and results of the tests are also described.

  17. Occupation Competency Profile: Gas Utility Operator Certificate Program.

    ERIC Educational Resources Information Center

    Alberta Learning, Edmonton. Apprenticeship and Industry Training.

    This document presents information about the apprenticeship training program of Alberta, Canada, in general and the gas utility operator certificate program in particular. The first part of the document discusses the following items: Alberta's apprenticeship and industry training system; the occupation committee and its members; the Alberta…

  18. Production and New Habits of TiN Ultrafine Particles Produced by DC Arc Discharge in N2 Gas

    NASA Astrophysics Data System (ADS)

    Guo, Yumei; Okazaki, Tsugio

    2004-02-01

    TiN ultrafine particles were prepared by DC arc discharge in N2 gas and observed by a scanning electron microscope (SEM) and transmission electron microscope (TEM). New habits of TiN were identified, which were a basic cubic shape bounded by six {100}, and its truncated forms bounded by {110} and/or {111}.

  19. Magnetic discharge accelerating diode for the gas-filled pulsed neutron generators based on inertial confinement of ions

    NASA Astrophysics Data System (ADS)

    Kozlovskij, K. I.; Shikanov, A. E.; Vovchenko, E. D.; Shatokhin, V. L.; Isaev, A. A.; Martynenko, A. S.

    2016-09-01

    The paper deals with magnetic discharge diode module with inertial electrostatic ions confinement for the gas-filled pulsed neutron generators. The basis of the design is geometry with the central hollow cathode surrounded by the outer cylindrical anode and electrodes made of permanent magnets. The induction magnitude about 0.1-0.4 T in the central region of the discharge volume ensures the confinement of electrons in the space of hollow (virtual) cathode and leads to space charge compensation of accelerated ions in the centre. The research results of different excitation modes in pulsed high-voltage discharge are presented. The stable form of the volume discharge preserveing the shape and amplitude of the pulse current in the pressure range of 10-3-10-1 Torr and at the accelerating voltage up to 200 kV was observed.

  20. Operating experience review of an INL gas monitoring system

    SciTech Connect

    Cadwallader, Lee C.; DeWall, K. G.; Herring, J. S.

    2015-03-12

    This article describes the operations of several types of gas monitors in use at the Idaho National Laboratory (INL) High Temperature Electrolysis Experiment (HTE) laboratory. The gases monitored in the lab room are hydrogen, carbon monoxide, carbon dioxide, and oxygen. The operating time, calibration, and both actual and unwanted alarms are described. The calibration session time durations are described. In addition, some simple calculations are given to estimate the reliability of these monitors and the results are compared to operating experiences of other types of monitors.

  1. Investigation of Electron Attachment and Dissociation Rates in C2F6/CH4 Electric Gas Discharges.

    DTIC Science & Technology

    1984-12-01

    33 Closed-Cycle Gas Flow Loop . . . . . . . 35 ’l ass Analysis . . . . . . . . . . . 37 )iagnostics and Data Reduction . . . . . . 39 V. Result; and...8217C’ t-IihcL portLiin or tie, d-Ischiarge currenTt pul2se’ i1rl1c- iLes attach:7eiit r;2te of 5 x 15Sec -1 for a gas i-iixturcE r:oC. () .1 /755, C.,F...potential to another. However, 0 to support a gas discharge, it is first necessary to form a 12 ." .? .. .. l I . ’....$l. . ]. , - i~. il - :,i .,7

  2. Hollow cathode operation at high discharge currents. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Friedly, Verlin Joe

    1990-01-01

    It was shown that ion thruster hollow cathode operation at high discharge current levels can induce reduced thruster lifetimes by causing cathode insert overheating and/or erosion of surfaces located downstream of the cathode. The erosion problem has been particularly baffling because the mechanism by which it occurs has not been understood. The experimental investigation described reveals the energies of the ions produced close to the cathode orifice can be several times the anode-to-cathode potential difference generally considered available to accelerate them. These energies (of order 50 eV) are sufficient to cause the observed erosion rates. The effects of discharge current (to 60 A), magnetic field configuration and the cathode flowrate, orifice diameter and insert design on the energies and current densities of these jet ions are examined. A model describing the mechanism by which the high energy ions could be produced when the anode-cathode potential difference is insufficient is proposed. The effects of discharge current on cathode temperature and internal pressure are also examined experimentally and described phenomenologically.

  3. Strontium isotope quantification of siderite, brine and acid mine drainage contributions to abandoned gas well discharges in the Appalachian Plateau

    SciTech Connect

    Chapman, Elizabeth C.; Capo, Rosemary C.; Stewart, Brian W.; Hedin, Robert S.; Weaver, Theodore J.; Edenborn, Harry M.

    2013-04-01

    Unplugged abandoned oil and gas wells in the Appalachian region can serve as conduits for the movement of waters impacted by fossil fuel extraction. Strontium isotope and geochemical analysis indicate that artesian discharges of water with high total dissolved solids (TDS) from a series of gas wells in western Pennsylvania result from the infiltration of acidic, low Fe (Fe < 10 mg/L) coal mine drainage (AMD) into shallow, siderite (iron carbonate)-cemented sandstone aquifers. The acidity from the AMD promotes dissolution of the carbonate, and metal- and sulfate-contaminated waters rise to the surface through compromised abandoned gas well casings. Strontium isotope mixing models suggest that neither upward migration of oil and gas brines from Devonian reservoirs associated with the wells nor dissolution of abundant nodular siderite present in the mine spoil through which recharge water percolates contribute significantly to the artesian gas well discharges. Natural Sr isotope composition can be a sensitive tool in the characterization of complex groundwater interactions and can be used to distinguish between inputs from deep and shallow contamination sources, as well as between groundwater and mineralogically similar but stratigraphically distinct rock units. This is of particular relevance to regions such as the Appalachian Basin, where a legacy of coal, oil and gas exploration is coupled with ongoing and future natural gas drilling into deep reservoirs.

  4. Strontium isotope quantification of siderite, brine and acid mine drainage contributions to abandoned gas well discharges in the Appalachian Plateau

    SciTech Connect

    Chapman, Elizabeth C.; Capo, Rosemary C.; Stewart, Brian W.

    2013-04-01

    Unplugged abandoned oil and gas wells in the Appalachian region can serve as conduits for the movement of waters impacted by fossil fuel extraction. Strontium isotope and geochemical analysis indicate that artesian discharges of water with high total dissolved solids (TDS) from a series of gas wells in western Pennsylvania result from the infiltration of acidic, low Fe (Fe < 10 mg/L) coal mine drainage (AMD) into shallow, siderite (iron carbonate)-cemented sandstone aquifers. The acidity from the AMD promotes dissolution of the carbonate, and metal- and sulfate-contaminated waters rise to the surface through compromised abandoned gas well casings. Strontium isotopemore » mixing models suggest that neither upward migration of oil and gas brines from Devonian reservoirs associated with the wells nor dissolution of abundant nodular siderite present in the mine spoil through which recharge water percolates contribute significantly to the artesian gas well discharges. Natural Sr isotope composition can be a sensitive tool in the characterization of complex groundwater interactions and can be used to distinguish between inputs from deep and shallow contamination sources, as well as between groundwater and mineralogically similar but stratigraphically distinct rock units. This is of particular relevance to regions such as the Appalachian Basin, where a legacy of coal, oil and gas exploration is coupled with ongoing and future natural gas drilling into deep reservoirs.« less

  5. Ozone production in parallel multichannel dielectric barrier discharge from oxygen and air: the influence of gas pressure

    NASA Astrophysics Data System (ADS)

    Yuan, Dingkun; Wang, Zhihua; Ding, Can; He, Yong; Whiddon, Ronald; Cen, Kefa

    2016-11-01

    This research aims to investigate the influence of gas pressure (0.1 Mpa-0.2 Mpa) on ozone generation in a parallel multichannel dielectric barrier discharge (DBD) reactor with a narrow gap (0.2 mm). In addition to determining ozone concentration and ozone yield characteristics with gas pressure variation, this paper examines the possible reasons leading to the inconsistency with previous reported results. All the experimental results are plotted on the basis of specific input energy (SIE) in order to conduct the comparison within identical power density. By reviewing the experimental results, the possible cause leading to the inconsistency concerning gas pressure dependences of ozone generation was found using different comparison bases. Results show that ozone generation is slightly suppressed with an increase of gas pressure with an initial increase in SIE. The results of the ozone yield show that an increase of gas pressure would have a favorable effect on ozone production efficiency with an SIE larger than 400 J l-1 in oxygen while ozone yield reaches the maximum at 0.14 Mpa with an SIE larger than 150 J l-1 in air. Increasing gas pressure would lead to a higher critical SIE value at which ozone yield firstly decreases with an increase of SIE both in oxygen and air. The results of nitrogen oxide byproducts show that both NO x byproducts emission and the discharge poisoning effect are suppressed by increasing gas pressure in air plasmas.

  6. Operators take second look at shallow gas. [Texas

    SciTech Connect

    Pitts, J.P.

    1978-07-01

    Mention Delaware Basin and the first thought is generally of deep gas. One is not inclined to think of the basin as a producer of shallow gas. However, the surprise of many, a shallow gas play has been going on in the northern part of Reeves County since 1976. The play was predicated on 2 old Texaco wells drilled in the Delaware sands in about 1964. Both were modest producers, but due to the remoteness of the area, the lack of pipelines, and the price of gas in the 1960s, the wells were abandoned. The proper conditions have now arrivedmore » and operators are going after the shallow 3,200-ft pay. Since the discovery of the Texaco wells in 1963, the price of natural gas has increased substantially and pipelines have traversed the remote corner of Reeves County, making development feasible. To date Enserch and Chevron are the leaders in the play. In the North Reaves 3200, Enserch has 16 wells, Texaco 7, Texas Pacific 4 and West Texas Gas 2. In the South Marsh, Chevron has it all locked up with 7 wells.« less

  7. The influence of bremsstrahlung on electric discharge streamers in N2, O2 gas mixtures

    NASA Astrophysics Data System (ADS)

    Köhn, C.; Chanrion, O.; Neubert, T.

    2017-01-01

    Streamers are ionization filaments of electric gas discharges. Negative polarity streamers propagate primarily through electron impact ionization, whereas positive streamers in air develop through ionization of oxygen by UV photons emitted by excited nitrogen; however, experiments show that positive streamers may develop even for low oxygen concentrations. Here we explore if bremsstrahlung ionization facilitates positive streamer propagation. To discriminate between effects of UV and bremsstrahlung ionization, we simulate the formation of a double headed streamer at three different oxygen concentrations: no oxygen, 1 ppm O2 and 20% O2, as in air. At these oxygen levels, UV-relative to bremsstrahlung ionization is zero, small, and large. The simulations are conducted with a particle-in-cell code in a cylindrically symmetric configuration at ambient electric field magnitudes three times the conventional breakdown field. We find that bremsstrahlung induced ionization in air, contrary to expectations, reduces the propagation velocity of both positive and negative streamers by about 15%. At low oxygen levels, positive streamers stall; however, bremsstrahlung creates branching sub-streamers emerging from the streamer front that allow propagation of the streamer. Negative streamers propagate more readily forming branching sub-streamers. These results are in agreement with experiments. At both polarities, ionization patches are created ahead of the streamer front. Electrons with the highest energies are in the sub-streamer tips and the patches.

  8. Gas discharge plasmas are effective in inactivating Bacillus and Clostridium spores.

    PubMed

    Tseng, Shawn; Abramzon, Nina; Jackson, James O; Lin, Wei-Jen

    2012-03-01

    Bacterial spores are the most resistant form of life and have been a major threat to public health and food safety. Nonthermal atmospheric gas discharge plasma is a novel sterilization method that leaves no chemical residue. In our study, a helium radio-frequency cold plasma jet was used to examine its sporicidal effect on selected strains of Bacillus and Clostridium. The species tested included Bacillus subtilis, Bacillus stearothermophilus, Clostridium sporogenes, Clostridium perfringens, Clostridium difficile, and Clostridium botulinum type A and type E. The plasmas were effective in inactivating selected Bacillus and Clostridia spores with D values (decimal reduction time) ranging from 2 to 8 min. Among all spores tested, C. botulinum type A and C. sporogenes were significantly more resistant to plasma inactivation than other species. Observations by phase contrast microscopy showed that B. subtilis spores were severely damaged by plasmas and the majority of the treated spores were unable to initiate the germination process. There was no detectable fragmentation of the DNA when the spores were treated for up to 20 min. The release of dipicolinic acid was observed almost immediately after the plasma treatment, indicating the spore envelope damage could occur quickly resulting in dipicolinic acid release and the reduction of spore resistance.

  9. Evaluating the use of gas discharge visualization to measure massage therapy outcomes

    PubMed Central

    Haun, Jolie; Patel, Nitin; Schwartz, Gary; Ritenbaugh, Cheryl

    2017-01-01

    Background The purpose of this study was to evaluate the short-term effects of massage therapy using gas discharge visualization (GDV), a computerized biophysical electrophoton capture (EPC), in tandem with traditional self-report measures to evaluate the use of GDV measurement to assess the bioenergetic whole-person effects of massage therapy. Methods This study used a single treatment group, pre–post-repeated measures design with a sample of 23 healthy adults. This study utilized a single 50-min full-body relaxation massage with participants. GDV measurement method, an EPC, and traditional paper-based measures evaluating pain, stress, muscle tension, and well-being were used to assess intervention outcomes. Results Significant differences were found between pre- and post-measures of well-being, pain, stress, muscle tension, and GDV parameters. Pearson correlations indicate the GDV measure is correlated with pain and stress, variables that impact the whole person. Conclusions This study demonstrates that GDV parameters may be used to indicate significant bioenergetic change from pre- to post-massage. Findings warrant further investigation with a larger diverse sample size and control group to further explore GDV as a measure of whole-person bioenergetic effects associated with massage. PMID:26087069

  10. Gas Discharge Visualization: An Imaging and Modeling Tool for Medical Biometrics

    PubMed Central

    Kostyuk, Nataliya; Cole, Phyadragren; Meghanathan, Natarajan; Isokpehi, Raphael D.; Cohly, Hari H. P.

    2011-01-01

    The need for automated identification of a disease makes the issue of medical biometrics very current in our society. Not all biometric tools available provide real-time feedback. We introduce gas discharge visualization (GDV) technique as one of the biometric tools that have the potential to identify deviations from the normal functional state at early stages and in real time. GDV is a nonintrusive technique to capture the physiological and psychoemotional status of a person and the functional status of different organs and organ systems through the electrophotonic emissions of fingertips placed on the surface of an impulse analyzer. This paper first introduces biometrics and its different types and then specifically focuses on medical biometrics and the potential applications of GDV in medical biometrics. We also present our previous experience with GDV in the research regarding autism and the potential use of GDV in combination with computer science for the potential development of biological pattern/biomarker for different kinds of health abnormalities including cancer and mental diseases. PMID:21747817

  11. Gas discharge visualization: an imaging and modeling tool for medical biometrics.

    PubMed

    Kostyuk, Nataliya; Cole, Phyadragren; Meghanathan, Natarajan; Isokpehi, Raphael D; Cohly, Hari H P

    2011-01-01

    The need for automated identification of a disease makes the issue of medical biometrics very current in our society. Not all biometric tools available provide real-time feedback. We introduce gas discharge visualization (GDV) technique as one of the biometric tools that have the potential to identify deviations from the normal functional state at early stages and in real time. GDV is a nonintrusive technique to capture the physiological and psychoemotional status of a person and the functional status of different organs and organ systems through the electrophotonic emissions of fingertips placed on the surface of an impulse analyzer. This paper first introduces biometrics and its different types and then specifically focuses on medical biometrics and the potential applications of GDV in medical biometrics. We also present our previous experience with GDV in the research regarding autism and the potential use of GDV in combination with computer science for the potential development of biological pattern/biomarker for different kinds of health abnormalities including cancer and mental diseases.

  12. Integrated scheduling of a container handling system with simultaneous loading and discharging operations

    NASA Astrophysics Data System (ADS)

    Li, Chen; Lu, Zhiqiang; Han, Xiaole; Zhang, Yuejun; Wang, Li

    2016-03-01

    The integrated scheduling of container handling systems aims to optimize the coordination and overall utilization of all handling equipment, so as to minimize the makespan of a given set of container tasks. A modified disjunctive graph is proposed and a mixed 0-1 programming model is formulated. A heuristic algorithm is presented, in which the original problem is divided into two subproblems. In the first subproblem, contiguous bay crane operations are applied to obtain a good quay crane schedule. In the second subproblem, proper internal truck and yard crane schedules are generated to match the given quay crane schedule. Furthermore, a genetic algorithm based on the heuristic algorithm is developed to search for better solutions. The computational results show that the proposed algorithm can efficiently find high-quality solutions. They also indicate the effectiveness of simultaneous loading and discharging operations compared with separate ones.

  13. Gas flow rate dependence of the discharge characteristics of a helium atmospheric pressure plasma jet interacting with a substrate

    NASA Astrophysics Data System (ADS)

    Yan, Wen; Economou, Demetre J.

    2017-10-01

    A 2D (axisymmetric) computational study of the discharge characteristics of an atmospheric pressure plasma jet as a function of gas flow rate was performed. The helium jet emerged from a dielectric tube, with an average gas flow velocity in the range 2.5-20 m s-1 (1 atm, 300 K) in a nitrogen ambient, and impinged on a substrate a short distance dowstream. The effect of the substrate conductivity (conductror versus insulator) was also studied. Whenever possible, simulation predictions were compared with published experimental observations. Discharge ignition and propagation in the dielectric tube were hardly affected by the He gas flow velocity. Most properties of the plasma jet, however, depended sensitively on the He gas flow velocity, which determined the concentration distributions of helium and nitrogen in the mixing layer forming in the gap between the tube exit and the substrate. At low gas flow velocity, the plasma jet evolved from a hollow (donut-shaped) feature to one where the maximum of electron density was on axis. When the gas flow velocity was high, the plasma jet maintained its hollow structure until it struck the substrate. For a conductive substrate, the radial ion fluxes to the surface were relatively uniform over a radius of ~0.4-0.8 mm, and the dominant ion flux was that of He+. For a dielectric substrate, the radial ion fluxes to the surface peaked on the symmetry axis at low He gas flow velocity, but a hollow ion flux distribution was observed at high gas flow velocity. At the same time, the main ion flux switched from N2+ to He2+ as the He gas flow velocity increased from a low to a high value. The diameter of the plasma ‘footprint’ on the substrate first increased with increasing He gas flow velocity, and eventually saturated with further increases in velocity.

  14. A prototype of an electric-discharge gas flow oxygen−iodine laser: I. Modeling of the processes of singlet oxygen generation in a transverse cryogenic slab RF discharge

    SciTech Connect

    Vagin, N. P.; Ionin, A. A., E-mail: aion@sci.lebedev.ru; Kochetov, I. V.

    2017-03-15

    The existing kinetic model describing self-sustained and electroionization discharges in mixtures enriched with singlet oxygen has been modified to calculate the characteristics of a flow RF discharge in molecular oxygen and its mixtures with helium. The simulations were performed in the gas plug-flow approximation, i.e., the evolution of the plasma components during their motion along the channel was represented as their evolution in time. The calculations were carried out for the O{sub 2}: He = 1: 0, 1: 1, 1: 2, and 1: 3 mixtures at an oxygen partial pressure of 7.5 Torr. It is shown that, under these conditions,more » volumetric gas heating in a discharge in pure molecular oxygen prevails over gas cooling via heat conduction even at an electrode temperature as low as ~100 K. When molecular oxygen is diluted with helium, the behavior of the gas temperature changes substantially: heat removal begins to prevail over volumetric gas heating, and the gas temperature at the outlet of the discharge zone drops to ~220–230 K at room gas temperature at the inlet, which is very important in the context of achieving the generation threshold in an electric-discharge oxygen−iodine laser based on a slab cryogenic RF discharge.« less

  15. A prototype of an electric-discharge gas flow oxygen−iodine laser: I. Modeling of the processes of singlet oxygen generation in a transverse cryogenic slab RF discharge

    SciTech Connect

    Vagin, N. P.; Ionin, A. A. Kochetov, I. V.; Napartovich, A. P.; Sinitsyn, D. V. Yuryshev, N. N.

    2017-03-15

    The existing kinetic model describing self-sustained and electroionization discharges in mixtures enriched with singlet oxygen has been modified to calculate the characteristics of a flow RF discharge in molecular oxygen and its mixtures with helium. The simulations were performed in the gas plug-flow approximation, i.e., the evolution of the plasma components during their motion along the channel was represented as their evolution in time. The calculations were carried out for the O{sub 2}: He = 1: 0, 1: 1, 1: 2, and 1: 3 mixtures at an oxygen partial pressure of 7.5 Torr. It is shown that, under these conditions, volumetric gas heating in a discharge in pure molecular oxygen prevails over gas cooling via heat conduction even at an electrode temperature as low as ~100 K. When molecular oxygen is diluted with helium, the behavior of the gas temperature changes substantially: heat removal begins to prevail over volumetric gas heating, and the gas temperature at the outlet of the discharge zone drops to ~220–230 K at room gas temperature at the inlet, which is very important in the context of achieving the generation threshold in an electric-discharge oxygen−iodine laser based on a slab cryogenic RF discharge.

  16. A prototype of an electric-discharge gas flow oxygen-iodine laser: I. Modeling of the processes of singlet oxygen generation in a transverse cryogenic slab RF discharge

    NASA Astrophysics Data System (ADS)

    Vagin, N. P.; Ionin, A. A.; Kochetov, I. V.; Napartovich, A. P.; Sinitsyn, D. V.; Yuryshev, N. N.

    2017-03-01

    The existing kinetic model describing self-sustained and electroionization discharges in mixtures enriched with singlet oxygen has been modified to calculate the characteristics of a flow RF discharge in molecular oxygen and its mixtures with helium. The simulations were performed in the gas plug-flow approximation, i.e., the evolution of the plasma components during their motion along the channel was represented as their evolution in time. The calculations were carried out for the O2: He = 1: 0, 1: 1, 1: 2, and 1: 3 mixtures at an oxygen partial pressure of 7.5 Torr. It is shown that, under these conditions, volumetric gas heating in a discharge in pure molecular oxygen prevails over gas cooling via heat conduction even at an electrode temperature as low as 100 K. When molecular oxygen is diluted with helium, the behavior of the gas temperature changes substantially: heat removal begins to prevail over volumetric gas heating, and the gas temperature at the outlet of the discharge zone drops to 220-230 K at room gas temperature at the inlet, which is very important in the context of achieving the generation threshold in an electric-discharge oxygen-iodine laser based on a slab cryogenic RF discharge.

  17. Prospecting for zones of contaminated ground-water discharge to streams using bottom-sediment gas bubbles

    USGS Publications Warehouse

    Vroblesky, Don A.; Lorah, Michelle M.

    1991-01-01

    Decomposition of organic-rich bottom sediment in a tidal creek in Maryland results in production of gas bubbles in the bottom sediment during summer and fall. In areas where volatile organic contaminants discharge from ground water, through the bottom sediment, and into the creek, part of the volatile contamination diffuses into the gas bubbles and is released to the atmosphere by ebullition. Collection and analysis of gas bubbles for their volatile organic contaminant content indicate that relative concentrations of the volatile organic contaminants in the gas bubbles are substantially higher in areas where the same contaminants occur in the ground water that discharges to the streams. Analyses of the bubbles located an area of previously unknown ground-water contamination. The method developed for this study consisted of disturbing the bottom sediment to release gas bubbles, and then capturing the bubbles in a polyethylene bag at the water-column surface. The captured gas was transferred either into sealable polyethylene bags for immediate analysis with a photoionization detector or by syringe to glass tubes containing wires coated with an activated-carbon adsorbent. Relative concentrations were determined by mass spectral analysis for chloroform and trichloroethylene.

  18. Pulsed electromagnetic gas accelleration. [incorporation of hollow cathode in plasma discharge and suitability determination of MPD discharge as plasmadynamic laser source

    NASA Technical Reports Server (NTRS)

    Jahn, R. G.

    1973-01-01

    Direct measurement with thermocouples of the power deposited in the anode of a multi-megawatt magnetoplasmadynamic discharge has shown the fractional anode power to decrease from 50% at 200 kW to 10% at 20 MW. Using local measurements of current density, electric potential, and electron temperature, the traditional model for heat conduction to the anode is found to be inadequate. Other experiments in which the voltage-current characteristics and exhaust velocities of MPD arcs using Plexiglas and boron nitride chamber insulators and various mass injection configurations show that ablation can affect nominal accelerator operation in several distinct ways. The incorporation of a hollow cathode in a 7 kA plasma discharge has shown that a stable current attachment can be realized in the cavity without the aid of cathode heaters, keeper electrodes, or emissive coatings.

  19. Activation of peroxydisulfate by gas-liquid pulsed discharge plasma to enhance the degradation of p-nitrophenol

    NASA Astrophysics Data System (ADS)

    Shang, Kefeng; Wang, Hao; Li, Jie; Lu, Na; Jiang, Nan; Wu, Yan

    2017-06-01

    Pulsed discharge in water and over water surfaces generates ultraviolet radiation, local high temperature, shock waves, and chemical reactive species, including hydroxyl radicals, hydrogen peroxide, and ozone. Pulsed discharge plasma (PDP) can oxidize and mineralize pollutants very efficiently, but high energy consumption restricts its application for industrial wastewater treatment. A novel method for improving the energy efficiency of wastewater treatment by PDP was proposed, in which peroxydisulfate (PDS) was added to wastewater and PDS was activated by PDP to produce more strong oxidizing radicals, including sulfate radicals and hydroxyl radicals, leading to a higher oxidation capacity for the PDP system. The experimental results show that the increase in solution conductivity slightly decreased the discharge power of the pulse discharge over the water surface. An increase in the discharge intensity improved the activation of PDS and therefore the degradation efficiency and energy efficiency of p-nitrophenol (PNP). An increase in the addition dosage of PDS greatly facilitated the degradation of PNP at a molar ratio of PDS to PNP of lower than 80:1, but the performance enhancement was no longer obvious at a dosage of more than 80:1. Under an applied voltage of 20 kV and a gas discharge gap of 2 mm, the degradation efficiency and energy efficiency of the PNP reached 90.7% and 45.0 mg kWh-1 for the plasma/PDS system, respectively, which was 34% and 18.0 mg kWh-1 higher than for the discharge plasma treatment alone. Analysis of the physical and chemical effects indicated that ozone and hydrogen peroxide were important for PNP degradation and UV irradiation and heat from the discharge plasma might be the main physical effects for the activation of PDS.

  20. Effect Of Gas Mixture Composition On Tar Removal Process In A Pulsed Corona Discharge Reactor

    NASA Astrophysics Data System (ADS)

    Filimonova E.; Naidis, G.

    2010-07-01

    The simulation of naphthalene (C10H8) removal from several gas mixtures (pure nitrogen, mixtures containing N2 with CO2, CO, H2, H2O, and biogas - the product of biomass gasification), has been investigated. The modeling is based on the experimental data obtained in the reactor with a pulsed positive corona discharge. The problem of simulation of the cleaning process includes description of two stages. The first, fast stage is generation of primary active species during streamer propagation. The second, slow stage is the chain of chemical transformations triggered by these species. The input parameters for the modeling of the second stage are G-values for generation of primary active species, obtained under consideration of streamer dynamics. Simulation of the second stage of the removal process takes into account the processes of chemical kinetics and diffusion outside and inside of streamer traces during multi-pulsed treatment. Besides neutral active species, streamer discharges produce electrons and ions. Primary positive ions (N2+, CO+, CO2+, H2+, H2O+) in a chain of fast ion-molecule reactions transform into more stable positive ions. The ions recombine with electrons. Both ion-molecule reactions and electron-ion recombination process are additional (to dissociation of gas molecules by electron impact in the streamer head) sources of neutral active species. The relative contribution of these sources to the G-values for H, OH and O is rather large. In our modeling two approaches have been used. At the first approach the contribution of ion-molecule reactions is estimated approximately assuming that the dominating stable ion is N4+ (in pure N2 and its mixtures with H2) or CO2+ (in mixtures including CO2). Other way is the calculations with kinetic scheme including the molecular ions, aquated ions such as H3O(H2O)m+, NO2(H2O)-, NO2(H2O)+ and other. The comparison of results of two approaches is presented. Only full kinetic scheme allowed describing the

  1. Investigations of the growth of the vapor-air shell of a gas discharge with a liquid electrolytic cathode of sodium hydroxide solution

    NASA Astrophysics Data System (ADS)

    Kashapov, R. N.; Kashapov, L. N.; Kashapov, N. F.

    2017-11-01

    Gas discharges with liquid electrodes are widely used in cleaning, polishing, hardening, forming a surface microrelief with specified parameters. Burning gas discharge in a number of cases occurs in the vapor-air shell, with film boiling of the electrolyte. The properties of the vapor-air shell strongly influence on the physical processes of the discharge. Investigation of the growth mechanism of the vapor-air shell and the determination of the main factors of influence are relevant for the optimization of applied processes. The structure of the discharge in the vapor-air shell is determined, and the presence of the discharge leader structure is established. Anomalous growth of the vapor-air shell of a gas discharge with a liquid electrolytic cathode was detected.

  2. Investigations of Biofilm-Forming Bacterial Cells by Atomic Force Microscopy Prior to and Following Treatment from Gas Discharge Plasmas

    NASA Astrophysics Data System (ADS)

    Vandervoort, K. G.; Joaquin, J. C.; Kwan, C.; Bray, J. D.; Torrico, R.; Abramzon, N.; Brelles-Marino, G.

    2007-03-01

    We present investigations of biofilm-forming bacteria before and after treatment from gas discharge plasmas. Gas discharge plasmas represent a way to inactivate bacteria under conditions where conventional disinfection methods are often ineffective. These conditions involve bacteria in biofilm communities, where cooperative interactions between cells make organisms less susceptible to standard killing methods. Rhizobium gallicum and Chromobacterium violaceum were imaged before and after plasma treatment using an atomic force microscope (AFM). In addition, cell wall elasticity was studied by measuring force distance curves as the AFM tip was pressed into the cell surface. Results for cell surface morphology and micromechanical properties for plasma treatments lasting from 5 to 60 minutes were obtained and will be presented.

  3. An atmospheric air gas-liquid diffuse discharge excited by bipolar nanosecond pulse in quartz container used for water sterilization

    NASA Astrophysics Data System (ADS)

    Wang, Sen; Yang, De-Zheng; Wang, Wen-Chun; Zhang, Shuai; Liu, Zhi-Jie; Tang, Kai; Song, Ying

    2013-12-01

    In this Letter, we report that the air gas-liquid diffuse discharge plasma excited by bipolar nanosecond pulse in quartz container with different bottom structures at atmospheric pressure. Optical diagnostic measurements show that bountiful chemically and biologically active species, which are beneficial for effective sterilization in some areas, are produced. Such diffuse plasmas are then used to treat drinking water containing the common microorganisms (Candida albicans and Escherichia coli). It is found that these plasmas can sterilize the microorganisms efficiently.

  4. Dependence of Ozone Generation on Gas Temperature Distribution in AC Atmospheric Pressure Dielectric Barrier Discharge in Oxygen

    NASA Astrophysics Data System (ADS)

    Takahashi, Go; Akashi, Haruaki

    AC atmospheric pressure multi-filament dielectric barrier discharge in oxygen has been simulated using two dimensional fluid model. In the discharge, three kinds of streamers have been obtained. They are primary streamers, small scale streamers and secondary streamers. The primary streamers are main streamers in the discharge and the small scale streamers are formed after the ceasing of the primary streamers. And the secondary streamers are formed on the trace of the primary streamers. In these streamers, the primary and the small scale streamers are very effective to generate O(3P) oxygen atoms which are precursor of ozone. And the ozone is generated mainly in the vicinity of the dielectrics. In high gas temperature region, ozone generation decreases in general. However, increase of the O(3P) oxygen atom density in high gas temperature region compensates decrease of ozone generation rate coefficient. As a result, amount of ozone generation has not changed. But if the effect of gas temperature was neglected, amount of ozone generation increases 10%.

  5. The bidirectional character of O2 concentration in pulsed dielectric barrier discharges in O2/N2 gas mixtures

    NASA Astrophysics Data System (ADS)

    Höft, H.; Kettlitz, M.; Weltmann, K.-D.; Brandenburg, R.

    2014-11-01

    This paper presents experimental results on the influence of O2 on the characteristics of dielectric barrier discharges (DBDs) at one and at half atmospheric pressure. Gas mixtures of 0.1-10 vol % O2 in N2 were investigated, as well as in virtually pure N2. Electrical data, simultaneous streak and intensified charge-coupled device images were recorded in pulsed driven dielectric barrier discharges of 0.8 mm gap in a single filament arrangement. The O2 concentration is shown to have a significant impact on the electrical characteristics, the temporal DBD development and its breakdown inception. Higher O2 concentrations (above 0.1 vol %) led to an ignition delay, a shorter discharge duration, increased discharge radius, higher discharge current maxima and larger velocities of the cathode directed streamers. For O2 concentrations below 0.01 vol %—i.e. nearly pure nitrogen—some of these effects were reversed. Moreover, the effects were more pronounced at a pressure of 0.5 bar compared to 1 bar. This result can be explained by the pressure dependent decay and recombination processes of positive nitrogen and oxygen ions.

  6. 77 FR 19282 - Draft NPDES General Permit for Discharges From the Oil and Gas Extraction Point Source Category...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-30

    ... proposed in this permit. Major changes also include definition of ``operator'', acute toxicity test for... on the EPA Region 6 Web site at: http://www.epa.gov/region6/water/npdes/genpermit/index.htm... pits are also proposed to be prohibited. Produced water discharges are prohibited, except from wells in...

  7. 25 CFR 226.27 - Gas for operating purposes and tribal use.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... OSAGE RESERVATION LANDS FOR OIL AND GAS MINING Operations § 226.27 Gas for operating purposes and tribal use. (a) Gas to be furnished oil lessee. Lessee of a producing gas lease shall furnish the oil lessee... determined by the Superintendent: Provided, That the oil lessee shall at his own expense and risk, furnish...

  8. Discharge dynamics and plasma density recovery by on/off switches of additional gas

    SciTech Connect

    Lee, Hyo-Chang; Kwon, Deuk-Chul; Oh, SeungJu; Kang, Hyun-Ju; Kim, Yu-Sin; Chung, Chin-Wook

    2016-06-15

    Measurement of the plasma density is investigated to study plasma dynamics by adding reactive gas (O{sub 2}) or rare gas (He) in Ar plasmas. When the O{sub 2} or He gas is added, plasma density is suddenly decreased, while the plasma density recovers slowly with gas off. It is found that the recovery time is strongly dependent on the gas flow rate, and it can be explained by effect of gas residence time. When the He gas is off in the Ar plasma, the plasma density is overshot compared to the case of the O{sub 2} gas pulsing due to enhanced ionizations by metastable atoms. Analysis and calculation for correlation between the plasma density dynamics and the gas pulsing are also presented in detail.

  9. Laser Wakefield Structures and Electron Acceleration in Gas Jet and Capillary Discharge Plasmas

    NASA Astrophysics Data System (ADS)

    Maksimchuk, Anatoly

    2007-11-01

    Laser-driven plasma wakefield accelerators have the potential to become the next generation of particle accelerators because of the very high acceleration gradients. The beam quality from such accelerators depends critically on the details plasma wave spatial structures. In experiments at the University of Michigan it was possible in a single shot by frequency domain holography (FDH) to visualize individual plasma waves produced by the 40 TW, 30 fs Hercules laser focused to the intensity of 10^19 W/cm^2 onto a supersonic He gas jet [1]. These holographic ``snapshots'' capture the evolution of multiple wake periods, and resolve wavefront curvature seen previously only in simulations. High-energy quasi-monoenergetic electron beams for plasma density in the specific range 1.5x10^19<=ne<=3.5x10^19 cm-3 were generated [2]. The experiments show that the energy, charge, divergence and pointing stability of the beam can be controlled by changing ne, and that higher electron energies and more stable beams are produced for lower densities. An optimized quasi-monoenergetic beam of over 300 MeV and 10 mrad angular divergence is demonstrated at a plasma density of ne=1.5x10^19 cm-3. The resulted relativistic electron beams have been used to perform gamma-neutron activation of ^12C and ^63Cu and photo-fission of ^238U with a record high reaction yields of ˜5x10^5/Joule [3]. Experiments performed with ablative capillary discharge plasma demonstrate stable guiding for laser power up to 10 TW with the transmission of 50% and guided intensity of ˜10^17 W/cm^2. Study of the staged electron acceleration have been performed which uses ablated plasma in front of the capillary to inject electrons into the wakefield structures. [1] N. H. Matlis et. al., Nature Physics 2, 749 (2006). [2] A. Maksimchuk et. al., Journal de Physique IV 133, 1123 (2006). [3] S. A. Reed et. al., Appl. Phys. Lett. 89, 231107 (2006).

  10. Does arousal interfere with operant conditioning of spike-wave discharges in genetic epileptic rats?

    PubMed

    Osterhagen, Lasse; Breteler, Marinus; van Luijtelaar, Gilles

    2010-06-01

    One of the ways in which brain computer interfaces can be used is neurofeedback (NF). Subjects use their brain activation to control an external device, and with this technique it is also possible to learn to control aspects of the brain activity by operant conditioning. Beneficial effects of NF training on seizure occurrence have been described in epileptic patients. Little research has been done about differentiating NF effectiveness by type of epilepsy, particularly, whether idiopathic generalized seizures are susceptible to NF. In this experiment, seizures that manifest themselves as spike-wave discharges (SWDs) in the EEG were reinforced during 10 sessions in 6 rats of the WAG/Rij strain, an animal model for absence epilepsy. EEG's were recorded before and after the training sessions. Reinforcing SWDs let to decreased SWD occurrences during training; however, the changes during training were not persistent in the post-training sessions. Because behavioural states are known to have an influence on the occurrence of SWDs, it is proposed that the reinforcement situation increased arousal which resulted in fewer SWDs. Additional tests supported this hypothesis. The outcomes have implications for the possibility to train SWDs with operant learning techniques. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  11. 25 CFR 226.27 - Gas for operating purposes and tribal use.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Gas for operating purposes and tribal use. 226.27 Section... OSAGE RESERVATION LANDS FOR OIL AND GAS MINING Operations § 226.27 Gas for operating purposes and tribal... wells shall be furnished any Tribal-owned building or enterprise at a rate not to exceed the price less...

  12. 25 CFR 226.27 - Gas for operating purposes and tribal use.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Gas for operating purposes and tribal use. 226.27 Section... OSAGE RESERVATION LANDS FOR OIL AND GAS MINING Operations § 226.27 Gas for operating purposes and tribal... wells shall be furnished any Tribal-owned building or enterprise at a rate not to exceed the price less...

  13. Investigation of operating parameters on CO2 splitting by dielectric barrier discharge plasma

    NASA Astrophysics Data System (ADS)

    Pan, CHEN; Jun, SHEN; Tangchun, RAN; Tao, YANG; Yongxiang, YIN

    2017-12-01

    Experiments of CO2 splitting by dielectric barrier discharge (DBD) plasma were carried out, and the influence of CO2 flow rate, plasma power, discharge voltage, discharge frequency on CO2 conversion and process energy efficiency were investigated. It was shown that the absolute quantity of CO2 decomposed was only proportional to the amount of conductive electrons across the discharge gap, and the electron amount was proportional to the discharge power; the energy efficiency of CO2 conversion was almost a constant at a lower level, which was limited by CO2 inherent discharge character that determined a constant gap electric field strength. This was the main reason why CO2 conversion rate decreased as the CO2 flow rate increase and process energy efficiency was decreased a little as applied frequency increased. Therefore, one can improve the CO2 conversion by less feed flow rate or larger discharge power in DBD plasma, but the energy efficiency is difficult to improve.

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

    NASA Astrophysics Data System (ADS)

    Khalaf, Mohammed K.; Mutlak, Rajaa H.; Khudiar, Ausama I.; Hial, Qahtan G.

    2017-06-01

    Nickel oxide thin films were deposited on glass substrates as the main gas sensor for H2 by the DC sputtering technique at various discharge voltages within the range of 1.8-2.5 kV. Their structural, optical and gas sensing properties were investigated by XRD, AFM, SEM, ultraviolet visible spectroscopy and home-made gas sensing measurement units. A diffraction peak in the direction of NiO (200) was observed for the sputtered films, thereby indicating that these films were polycrystalline in nature. The optical band gap of the films decreased from 3.8 to 3.5 eV when the thickness of the films was increased from 83.5 to 164.4 nm in relation to an increase in the sputtering discharge voltage from 1.8 to 2.5 kV, respectively. The gas sensitivity performance of the NiO films that were formed was studied and the electrical responses of the NiO-based sensors toward different H2 concentrations were also considered. The sensitivity of the gas sensor increased with the working temperature and H2 gas concentration. The thickness of the NiO thin films was also an important parameter in determining the properties of the NiO films as H2 sensors. It was shown in this study that NiO films have the capability to detect H2 concentrations below 3% in wet air, a feature that allows this material to be used directly for the monitoring of the environment.

  15. Fast gas heating in N2/O2 mixtures under nanosecond surface dielectric barrier discharge: the effects of gas pressure and composition

    PubMed Central

    Nudnova, M. M; Kindysheva, S. V; Aleksandrov, N. L; Starikovskii, A. Yu

    2015-01-01

    The fractional electron power quickly transferred to heat in non-equilibrium plasmas was studied experimentally and theoretically in N2/O2 mixtures subjected to high electric fields. Measurements were performed in and after a nanosecond surface dielectric barrier discharge at various (300–750 Torr) gas pressures and (50–100%) N2 percentages. Observations showed that the efficiency of fast gas heating is almost independent of pressure and becomes more profound when the fraction of O2 in N2/O2 mixtures increases. The processes that contribute towards the fast transfer of electron energy to thermal energy were numerically simulated under the conditions considered. Calculations were compared with measurements and the main channels of fast gas heating were analysed at the gas pressures, compositions and electric fields under study. It was shown that efficient fast gas heating in the mixtures with high fraction of O2 is due to a notable contribution of heat release during quenching of electronically excited N2 states in collisions with O2 molecules and to ion–ion recombination. The effect of hydrocarbon addition to air on fast gas heating was numerically estimated. It was concluded that the fractional electron power transferred to heat in air, as a first approximation, could be used to estimate this effect in lean and stoichiometric hydrocarbon–air mixtures. PMID:26170431

  16. 75 FR 20271 - Oil and Gas and Sulphur Operations in the Outer Continental Shelf-Oil and Gas Production...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-19

    ... Minerals Management Service 30 CFR Part 250 RIN 1010-AD12 Oil and Gas and Sulphur Operations in the Outer Continental Shelf--Oil and Gas Production Requirements AGENCY: Minerals Management Service (MMS), Interior. ACTION: Final rule. SUMMARY: The MMS is amending the regulations regarding oil and natural gas production...

  17. Landau Damping and Anomalous Skin Effect in Low-pressure Gas Discharges: Self-consistent Treatment of Collisionless Heating

    SciTech Connect

    Igor D. Kaganovich; Oleg V. Polomarov; Constantine E. Theodosiou

    2004-01-30

    In low-pressure discharges, where the electron mean free path is larger or comparable with the discharge length, the electron dynamics is essentially nonlocal. Moreover, the electron energy distribution function (EEDF) deviates considerably from a Maxwellian. Therefore, an accurate kinetic description of the low-pressure discharges requires knowledge of the nonlocal conductivity operator and calculation of the non-Maxwellian EEDF. The previous treatments made use of simplifying assumptions: a uniform density profile and a Maxwellian EEDF. In the present study a self-consistent system of equations for the kinetic description of nonlocal, nonuniform, nearly collisionless plasmas of low-pressure discharges is reported. It consists of the nonlocal conductivity operator and the averaged kinetic equation for calculation of the non-Maxwellian EEDF. This system was applied to the calculation of collisionless heating in capacitively and inductively coupled plasmas. In particular, the importance of accounting for the nonuniform plasma density profile for computing the current density profile and the EEDF is demonstrated. The enhancement of collisionless heating due to the bounce resonance between the electron motion in the potential well and the external radio-frequency electric field is investigated. It is shown that a nonlinear and self-consistent treatment is necessary for the correct description of collisionless heating.

  18. Removal Dynamics of Nitric Oxide (NO) Pollutant Gas by Pulse-Discharged Plasma Technique

    PubMed Central

    Zhang, Lianshui; Wang, Xiaojun; Lai, Weidong; Cheng, Xueliang; Zhao, Kuifang

    2014-01-01

    Nonthermal plasma technique has drawn extensive attentions for removal of air pollutants such as NOx and SO2. The NO removal mechanism in pulse discharged plasma is discussed in this paper. Emission spectra diagnosis indicates that the higher the discharge voltage is, the more the NO are removed and transformed into O, N, N2, NO2, and so forth. Plasma electron temperature T e is ranged from 6400 K at 2.4 kV discharge voltage to 9500 K at 4.8 kV. After establishing a zero-dimensional chemical reaction kinetic model, the major reaction paths are clarified as the electron collision dissociation of NO into N and O during discharge and followed by single substitution of N on NO to form N2 during and after discharge, compared with the small fraction of NO2 formed by oxidizing NO. The reaction directions can be adjusted by N2 additive, and the optimal N2/NO mixing ratio is 2 : 1. Such a ratio not only compensates the disadvantage of electron competitive consumption by the mixed N2, but also heightens the total NO removal extent through accelerating the NO oxidization process. PMID:24737985

  19. Optical characteristics and parameters of gas-discharge plasma in a mixture of mercury dibromide vapor with neon

    SciTech Connect

    Malinina, A. A. Malinin, A. N.

    2013-12-15

    Results are presented from studies of the optical characteristics and parameters of plasma of a dielectric barrier discharge in a mixture of mercury dibromide vapor with neon—the working medium of a non-coaxial exciplex gas-discharge emitter. The electron energy distribution function, the transport characteristics, the specific power losses for electron processes, the electron density and temperature, and the rate constants for the processes of elastic and inelastic electron scattering by the working mixture components are determined as functions of the reduced electric field. The rate constant of the process leading to the formation of exciplex mercury monobromide molecules is found to be 1.6 × 10{sup −14} m{sup 3}/s for a reduced electric field of E/N = 15 Td, at which the maximum emission intensity in the blue-green spectral region (λ{sub max} = 502 nm) was observed in this experiment.

  20. Effects of gas temperature in the plasma layer on RONS generation in array-type dielectric barrier discharge at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Yoon, Sung-Young; Yi, Changho; Eom, Sangheum; Park, Seungil; Kim, Seong Bong; Ryu, Seungmin; Yoo, Suk Jae

    2017-12-01

    In this work, we studied the control of plasma-produced species under a fixed gas composition (i.e., ambient air) in a 10 kHz-driven array-type dielectric barrier atmospheric-pressure plasma discharge. Instead of the gas composition, only the gas velocity was controlled. Thus, the plasma-maintenance cost was considerably lower than methods such as external N2 or O2 injection. The plasma-produced species were monitored using Fourier transformed infrared spectroscopy. The discharge properties were measured using a voltage probe, current probe, infrared camera, and optical emission spectroscopy. The results showed that the major plasma products largely depend on the gas temperature in the plasma discharge layer. The gas temperature in the plasma discharge layer was significantly different to the temperature of the ceramic adjacent to the plasma discharge layer, even in the small discharge power density of ˜15 W/cm2 or ˜100 W/cm3. Because the vibrational excitation of N2 was suppressed by the higher gas flow, the major plasma-produced species shifted from NOx in low flow to O3 in high flow.

  1. Biotransformation of natural gas and oil compounds associated with marine oil discharges.

    PubMed

    Brakstad, Odd Gunnar; Almås, Inger K; Krause, Daniel Franklin

    2017-09-01

    Field data from the Deepwater Horizon (DWH) oil spill in the Gulf of Mexico (GoM) suggested that oxidation of gas compounds stimulated biodegradation of oil compounds in the deep sea plume. We performed experiments with local seawater from a Norwegian fjord to examine if the presence of dissolved gas compounds (methane, ethane and propane) affected biodegradation of volatile oil compounds, and if oil compounds likewise affected gas compound oxidation. The results from the experiment showed comparable oil compound biotransformation rates in seawater at 5 °C between seawater with and without soluble gases. Gas oxidation was not affected by the presence of volatile oil compounds. Contrary to DWH deep sea plume data, propane oxidation was not faster than methane oxidation. These data may reflect variations between biodegradation of oil and gas in seawater environments with different history of oil and gas exposure. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Mercury distribution in seawater discharged from a coal-fired power plant equipped with a seawater flue gas desulfurization system.

    PubMed

    Liu, Xiyao; Sun, Lumin; Yuan, Dongxing; Yin, Liqian; Chen, Jinsheng; Liu, Yaoxing; Liu, Chengyu; Liang, Ying; Lin, Fangfang

    2011-09-01

    More and more coal-fired power plants equipped with seawater flue gas desulfurization systems have been built in coastal areas. They release large amount of mercury (Hg)-containing waste seawater into the adjacent seas. However, very limited impact studies have been carried out. Our research targeted the distribution of Hg in the seawater, sediment, biota, and atmosphere, and its environmental transportation. Seawater samples were collected from five sites: 1, sea areas adjacent to the power plant; 2, near discharge outlets; 3, the aeration pool of the power plant; and 4 and 5, two reference sites. The total gaseous Hg was determined in situ with a Tekran 2537B. Analyses of total Hg (TM) followed the USEPA methods. In most part of the study area, TM concentrations were close to the reference values and Hg transfer from the seawater into the sediment and biota was not obvious. However, in the aeration pool and near the waste discharge outlets, atmospheric and surface seawater concentrations of TM were much higher, compared with those at a reference site. The concentration ranges of total gaseous Hg and TM in seawater were 3.83-8.60 ng/m(3) and 79.0-198 ng/L near the discharge outlets, 7.23-13.5 ng/m(3) and 186-616 ng/L in the aeration pool, and 2.98-4.06 ng/m(3) and 0.47-1.87 ng/L at a reference point. This study suggested that the Hg in the flue gas desulfurization waste seawater was not only transported and diluted with sea currents, but also could possibly be transferred into the atmosphere from the aeration pool and from the discharge outlets.

  3. The role of gas composition in plasma-dust structures in RF discharge

    SciTech Connect

    Maiorov, S. A.; Golyatina, R. I.

    2015-03-15

    The influence of a mixture of light and heavy gases, i.e., helium and argon, on plasma-dust structures in the radiofrequency discharge has been studied. The dust chains in the sheath of the radiofrequency discharge, the average distance between the dust particles and their chains, have been analyzed. A significant effect of small amounts of argon on the correlation characteristics of dust particles has been observed. The results of numerical simulation of ion and electron drift in the mixture of helium and argon are presented. It is shown that even 1% of argon admixture to helium produces such an effect that argon ions become the main components of the discharge, as they drift with lightweight helium forming a strongly anisotropic velocity distribution function.

  4. Benthic foraminiferal responses to operational drill cutting discharge in the SW Barents Sea - a case study.

    NASA Astrophysics Data System (ADS)

    Aagaard-Sørensen, Steffen; Junttila, Juho; Dijkstra, Noortje

    2016-04-01

    Petroleum related exploration activities started in the Barents Sea 1980, reaching 97 exploration wells drilled per January 2013. The biggest operational discharge from drilling operations in the Barents Sea is the release of drill cuttings (crushed seabed and/or bedrock) and water based drilling muds including the commonly used weighing material barite (BaSO4). Barium (Ba), a constituent of barite, does not degrade and can be used to evaluate dispersion and accumulation of drill waste. The environmental impact associated with exploration drilling within the Goliat Field, SW Barents Sea in 2006 was evaluated via a multiproxy investigation of local sediments. The sediments were retrieved in November 2014 at ~350 meters water depth and coring sites were selected at distances of 5, 30, 60, 125 and 250 meters from the drill hole in the eastward downstream direction. The dispersion pattern of drill waste was estimated via measurements of sediment parameters including grain size distribution and water content in addition to heavy metal and total organic carbon contents. The environmental impact was evaluated via micro faunal analysis based on benthic foraminiferal (marine shell bearing protists) fauna composition and concentration changes. Observing the sediment parameters, most notably Ba levels, reveals that dispersion of drill waste was limited to <125 meters from the drill site with drill waste thicknesses decreasing downstream. The abruptness and quantity of drill waste sedimentation initially smothered the foraminiferal fauna at ≤ 30 meters from the drill site, while at a distance of 60 meters, the fauna seemingly survived and bioturbation persisted. Analysis of the live (Nov 2014) foraminiferal fauna reveals a natural species composition at all distances from the drill site within the top sediments (0-5 cm core depth). Furthermore, the fossil foraminiferal fauna composition found within post-impacted top sediment sections, particularly in the cores situated at

  5. Integrated input protection against discharges for Micro Pattern Gas Detectors readout ASICs

    NASA Astrophysics Data System (ADS)

    Fiutowski, T.; Dąbrowski, W.; Koperny, S.; Wiącek, P.

    2017-02-01

    Immunity against possible random discharges inside active detector volume of MPGDs is one of the key aspects that should be addressed in the design of the front-end electronics. This issue becomes particularly critical for systems with high channel counts and high density readout employing the front-end electronics built as multichannel ASICs implemented in modern CMOS technologies, for which the breakdown voltages are in the range of a few Volts. The paper presents the design of various input protection structures integrated in the ASIC manufactured in a 350 nm CMOS process and test results using an electrical circuit to mimic discharges in the detectors.

  6. Model operating permits for natural gas processing plants

    SciTech Connect

    Arend, C.

    1995-12-31

    Major sources as defined in Title V of the Clean Air Act Amendments of 1990 that are required to submit an operating permit application will need to: Evaluate their compliance status; Determine a strategic method of presenting the general and specific conditions of their Model Operating Permit (MOP); Maintain compliance with air quality regulations. A MOP is prepared to assist permitting agencies and affected facilities in the development of operating permits for a specific source category. This paper includes a brief discussion of example permit conditions that may be applicable to various types of Title V sources. A MOP for a generic natural gas processing plant is provided as an example. The MOP should include a general description of the production process and identify emission sources. The two primary elements that comprise a MOP are: Provisions of all existing state and/or local air permits; Identification of general and specific conditions for the Title V permit. The general provisions will include overall compliance with all Clean Air Act Titles. The specific provisions include monitoring, record keeping, and reporting. Although Title V MOPs are prepared on a case-by-case basis, this paper will provide a general guideline of the requirements for preparation of a MOP. Regulatory agencies have indicated that a MOP included in the Title V application will assist in preparation of the final permit provisions, minimize delays in securing a permit, and provide support during the public notification process.

  7. 40 CFR Appendix B to Part 434 - Baseline Determination and Compliance Monitoring for Pre-existing Discharges at Remining Operations

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS COAL MINING POINT... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Baseline Determination and Compliance... establishing effluent limitations for pre-existing discharges at coal remining operations, in accordance with...

  8. 40 CFR Appendix B to Part 434 - Baseline Determination and Compliance Monitoring for Pre-existing Discharges at Remining Operations

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS COAL MINING POINT... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Baseline Determination and Compliance... establishing effluent limitations for pre-existing discharges at coal remining operations, in accordance with...

  9. ACTIVE MEDIA: Optical characteristics of the gas-discharge plasma of working mixtures in an excimer HgBr/HgI radiation source

    NASA Astrophysics Data System (ADS)

    Malinin, A. N.

    2005-03-01

    The composition and partial pressures were determined for the components of gas mixtures which provide the maximum emission yield simultaneously at two wavelengths 502 nm and 444 nm in the self-heating regime of an excimer HgBr/HgI radiation source excited by a barrier discharge. The conditions for prolonged (no less than 4 × 106 pulses) stable operation at high pulse repetition rates f = 0.5 - 10 kHz are determined. Pulsed and average (for f = 5 kHz) output power densities of 270 W cm-3 and 65 mW cm-3, respectively, and the pump-to-output power conversion efficiency of ~30% were achieved. The processes increasing the population of the upper B2Σ1/2+ state of mercury monohalides are discussed.

  10. Effect of Dam operation on monthly and annual trends of flow discharge in the Qom Rood Watershed, Iran

    NASA Astrophysics Data System (ADS)

    Yaghmaei, Hiva; Sadeghi, Seyed Hamidreza; Moradi, Hamidreza; Gholamalifard, Mehdi

    2018-02-01

    Trends in flow discharge, temperature and rainfall from the Qom Rood Watershed, Iran, for a period of 1979-2016 were analyzed at monthly and annual time scales. Trend analyses were conducted using the Mann-Kendall test, the double-mass curve of mean annual discharge versus rainfall, and rainfall-runoff relationship before and after the 15 Khordad Dam operation. Multiple regression of flow discharge against rainfall and temperature was used to determine the residual trend at four meteorological and hydrological stations located upstream and downstream of the Qom Rood Watershed. Results showed that the temperature at the upstream and downstream stations did not have any significant trend, but a significant decreasing trend (P < .05) in rainfall was detected only in May (z = -1.66) at the downstream stations. There was a significant positive trend (P < .05) in rainfall in February (z = 2.22) and July (z = 2.15) at the upstream stations, and in October (z = 2.3) and November (z = 1.8) at the downstream stations. However, there was a noticeable decrease in monthly and annual flow discharge, and residual trend at 99% significance level at the downstream stations. At the upstream stations, the flow discharges had significant (P < .05) declining trend in all months, but annual flow discharge did not change significantly. Analysis of double mass curve between runoff and rainfall at the downstream stations showed an inconsistency in the line slope concordant with the time of 15 Khordad Dam operation. Annual mean discharge at the upstream stations did not show a significant change before and after 15 Khordad Dam operation. However, annual flow magnitude decreased significantly by 87.5 and 81.7% in Shad Abad and KoohSefid, respectively. These results confirmed that natural driving forces did not affect flow discharge changes and the observed decreasing tendency in flow discharge at the downstream stations was due to 15 Khordad Dam, and at the upstream stations due to diversion

  11. 43 CFR 3151.1 - Notice of intent to conduct oil and gas geophysical exploration operations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Notice of intent to conduct oil and gas...) ONSHORE OIL AND GAS GEOPHYSICAL EXPLORATION Exploration Outside of Alaska § 3151.1 Notice of intent to conduct oil and gas geophysical exploration operations. Parties wishing to conduct oil and gas geophysical...

  12. 43 CFR 3151.1 - Notice of intent to conduct oil and gas geophysical exploration operations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Notice of intent to conduct oil and gas...) ONSHORE OIL AND GAS GEOPHYSICAL EXPLORATION Exploration Outside of Alaska § 3151.1 Notice of intent to conduct oil and gas geophysical exploration operations. Parties wishing to conduct oil and gas geophysical...

  13. 43 CFR 3151.1 - Notice of intent to conduct oil and gas geophysical exploration operations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Notice of intent to conduct oil and gas...) ONSHORE OIL AND GAS GEOPHYSICAL EXPLORATION Exploration Outside of Alaska § 3151.1 Notice of intent to conduct oil and gas geophysical exploration operations. Parties wishing to conduct oil and gas geophysical...

  14. 43 CFR 3151.1 - Notice of intent to conduct oil and gas geophysical exploration operations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Notice of intent to conduct oil and gas...) ONSHORE OIL AND GAS GEOPHYSICAL EXPLORATION Exploration Outside of Alaska § 3151.1 Notice of intent to conduct oil and gas geophysical exploration operations. Parties wishing to conduct oil and gas geophysical...

  15. Comparative study of glow discharge wall conditioning using H{sub 2} and Ar-H{sub 2} gas mixture of ADITYA Tokamak vacuum vessel

    SciTech Connect

    Jadeja, K.A.; Patel, K.M.; Tanna, R.L.; and others

    2014-07-01

    Low temperature glow discharge wall conditioning (GDC) using H{sub 2} gas is effective in reduction of oxygen and carbon (low-Z) contain impurities on near surface region of vessel wall. The high retention of hydrogen in vessel wall/components due to long operation of H{sub 2} GDC increases hydrogen out-gassing during tokamak operation and affects the production of high temperature plasma. The hydrogen retention can be reduced using inert gas GDC by sputter cleaning for short duration. But in that case the out-gassing rate of inert gas increases, that again impairs the plasma performance. To overcome above problems, the GDC with hydrogen-inert gas mixture can be used for better removal of C and O surface contaminants and low hydrogen retention in surface. In ADITYA tokamak, H{sub 2}-GDC is carried out regularly after plasma operation, while the GDC with argon-hydrogen (Ar-H{sub 2}) mixture has been experimentally tested to observe the reduction of oxygen and carbon impurities along with low hydrogen retention. In Ar-H{sub 2} GDC, the reason being the formation of ArH{sup +} hydride ions, which has quite long life and more energy compared to H{sub 2}{sup +} ions formed in H{sub 2} GDC for breaking the bond of wall molecules. A systematic comparative study of H{sub 2} GDC and Ar-H{sub 2} Mixture GDC by changing the mixture ratio has been carried out in ADITYA tokamak. The relative levels of oxygen and carbon contain impurities have been measured using residual gas analyzer in both GDC's. We have observed a substantial reduction in oxygen and carbon impurities with a significant improvement in wall condition with Ar-H{sub 2} GDC compared to the H{sub 2} GDC. The effect of wall conditioning by Ar-H{sub 2} GDC on the performance of high temperature plasma operation will be presented in this paper. (author)

  16. Comparative study of glow discharge wall conditioning using H{sub 2} and Ar-H{sub 2} gas mixture of ADITYA Tokamak vacuum vessel

    SciTech Connect

    Jadeja, K.A.; Patel, K.M.; Tanna, R.L., E-mail: kumarpal@ipr.res.in

    2014-07-01

    Low temperature glow discharge wall conditioning (GDC) using H{sub 2} gas is effective in reduction of oxygen and carbon (low-Z) contain impurities on near surface region of vessel wall. The high retention of hydrogen in vessel wall/components due to long operation of H{sub 2} GDC increases hydrogen out-gassing during tokamak operation and affects the production of high temperature plasma. The hydrogen retention can be reduced using inert gas GDC by sputter cleaning for short duration. But in that case the out-gassing rate of inert gas increases, that again impairs the plasma performance. To overcome above problems, the GDC with hydrogen-inertmore » gas mixture can be used for better removal of C and O surface contaminants and low hydrogen retention in surface. In ADITYA tokamak, H{sub 2}-GDC is carried out regularly after plasma operation, while the GDC with argon-hydrogen (Ar-H{sub 2}) mixture has been experimentally tested to observe the reduction of oxygen and carbon impurities along with low hydrogen retention. In Ar-H{sub 2} GDC, the reason being the formation of ArH{sup +} hydride ions, which has quite long life and more energy compared to H{sub 2}{sup +} ions formed in H{sub 2} GDC for breaking the bond of wall molecules. A systematic comparative study of H{sub 2} GDC and Ar-H{sub 2} Mixture GDC by changing the mixture ratio has been carried out in ADITYA tokamak. The relative levels of oxygen and carbon contain impurities have been measured using residual gas analyzer in both GDC's. We have observed a substantial reduction in oxygen and carbon impurities with a significant improvement in wall condition with Ar-H{sub 2} GDC compared to the H{sub 2} GDC. The effect of wall conditioning by Ar-H{sub 2} GDC on the performance of high temperature plasma operation will be presented in this paper. (author)« less

  17. Thermal equilibrium in gas-discharge plasma of low pressure mercury lamp

    NASA Astrophysics Data System (ADS)

    Gorbunkov, V. I.; Solomonov, V. I.

    2015-12-01

    A study was conducted emission spectra germicidal low pressure mercury lamp at currents 100-306 mA located in a closed opaque cavity. It is shown that the lamps located in the cavity with perfectly reflecting and absorbing internal surfaces, in the emission resonance line of mercury is dominant at λr = 253.65 nm. The same pattern is observed in the tube placed in a cavity with diffusely reflecting surface at a low current of about 100 mA. However the picture of spectrum changes at higher discharge current. The spectrum of the lamp with arc discharge at a current of 306 mA contains the maxima of the spectral lines. Its intensities are approximately described by Planck's radiation law at the temperature of 9270 +/- 230 K. The mechanisms of establish thermal equilibrium are discussed.

  18. In situ plasma cleaning of ITER diagnostic mirrors in noble-gas RF discharge

    NASA Astrophysics Data System (ADS)

    Dmitriev, A. M.; Babinov, N. A.; Bazhenov, A. N.; Bukreev, I. M.; Kochergin, M. M.; Koval, A. N.; Kurskiev, G. S.; Litvinov, A. E.; Masyukevich, S. V.; Mukhin, E. E.; Razdobarin, A. G.; Samsonov, D. S.; Solokha, V. V.; Tolstyakov, S. Yu; Andrew, P.; Leipold, F.; Shigin, P. A.; Reichle, R.; Bukhovets, V. L.; Gorodetsky, A. E.; Markin, A. V.; Zakharov, A. P.; Zalavutdinov, R. Kh; Chernakov, An P.; Chernakov, Al P.; Chernakov, P. V.; Chernoizumskaya, T. V.; Kobelev, A. A.; Smirnov, A. S.; Marzinovsky, I. A.

    2017-12-01

    The development of the first mirror cleaning and recovery system is one of the challenges for all optical diagnostics in ITER. This study is focused on capacitively coupled radio frequency (CCRF) discharge as a promising method for removal of metal deposits. The physical aspects of the RF discharge application are discussed with a focus on implementation under ITER conditions. The effective sputtering rates of Be, W and Mo were calculated as a function of applied frequency and absorbed power for noble gases—He, Ne, Ar, Kr, Xe, taking into account complex shape of the ion energy distribution function in the electrode sheaths. Helium is shown to be a good candidate for cleaning Mo mirrors from Be deposits in the frequency range ∼80–100 MHz and pressure of a few Pa.

  19. Accurate in-situ gas temperature measurements in dielectric barrier discharges at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Wertheimer, Michael R.; Ahlawat, Meenu; Saoudi, Bachir; Kashyap, Raman

    2012-05-01

    Atmospheric pressure (AP) dielectric barrier discharges are frequently of interest for treating delicate substrates such as polymers or biological materials. In spite of its capital importance, thermometry in AP plasmas is subject to much uncertainty. We report temperature measurements in noble gases, nitrogen, and air using sensitive, accurate fibre-optic instrumentation that is a priori immune towards high voltages and high-frequency electromagnetic fields generally encountered in plasma environments.

  20. Improvement of Technological Properties of a Vegetal Tanning Agent in Gas Discharge Plasma

    NASA Astrophysics Data System (ADS)

    Khairullin, A. K.; Voznesensky, E. F.; Rakhmatullina, G. R.; Sabirov, A. M.; Tikhonova, N. V.

    2017-11-01

    The article considers the possibility of modification of the vegetal tanning agent quebracho in the plasma of a radio-frequency induction discharge at low pressure. It is established that plasma treatment leads to a decrease in the size of colloid fractions and a decrease in the molecular weight, while the functionality of the vegetal tanning agent is preserved. Application of the obtained product in the process of leather retanning allows improving its physical, mechanical and consumer properties.

  1. Requirements for long-life operation of inert gas hollow cathodes: Preliminary report

    NASA Technical Reports Server (NTRS)

    Verhey, Timothy R.; Macrae, Gregory S.

    1990-01-01

    An experimental investigation was initiated to establish conditioning procedures for reliable hollow cathode operation via the characterization of critical parameters in a representative cathode test facility. From vacuum pumpdown rates, it was found that approximately 1.5 hours were required to achieve pressure levels within 5 percent of the lowest attainable pressure for this facility, depending on the purge conditions. The facility atmosphere was determined by a residual gas analyzer to be composed of primarily air and water vapor. The effects of vacuum pumping and inert gas purging were evaluated. A maximum effective leakage rate of 2.0 x 10(exp -3)sccm was observed and its probable causes were examined. An extended test of a 0.64 cm diameter Mo-Re hollow cathode was successfully completed. This test ran for 504 hours at an emission current of 23.0 amperes and a xenon flow rate of 6.1 sccm. Discharge voltage rose continuously from 15 to 21 volts over the course of the test. The temperature of the cathode body during the test was relatively stable at 1160 C. Post-test examination revealed ion-bombardment texturing of the orifice plate to be the only detectable sign of wear on the hollow cathode.

  2. [Occupational exposure to enflurane and laughing gas in operating rooms].

    PubMed

    Hoerauf, K; Mayer, T; Hobbhahn, J

    1996-02-01

    Current scientific evidence suggests that chronic exposure to trace concentrations of anaesthetic gases may result in various forms of untoward health responses in operating room personnel. Although there are no clear dose-effect-relationships, in Germany threshold values (MAK-values) exist for nitrous oxide of 100 ppm and for enflurane of 20 ppm. Aim of this investigation was, to determine the exposure of the operating room personnel under modern working conditions using a standardized anaesthetic procedure. By means of a direct-reading, high sensitive gas monitor trace concentrations of nitrous oxide and enflurane were measured at three personnel-related (surgeon, anaesthetist, auxiliary nurse) and a potential leakage source (patient's mouth). The calculation and assessment of the measured concentrations followed the prescriptions of the technical rules for hazardous substances 402 and 403 (TRGS 402 and 403). The personnel-related concentrations were clearly under the MAK-values of 100 ppm nitrous oxide and/or 20 ppm enflurane. The time weighted averages were for the personnel-related measurement points, indicated in ppm for nitrous oxide and enflurane, respectively: "surgeon" 28.3/0.25, "anaesthetist" 39.3/0.34 and "auxiliary nurse" 64.6/0.57. At the leakage source "patient's mouth" time weighted averages of 317 ppm nitrous oxide and 3.79 ppm enflurane were measured. Under air-conditioning with a high air change rate, a central scavenging system and low leakage anaesthesia machine low trace concentrations of anaesthetic gases were measured. Despite an average contamination of approx. 300 ppm nitrous oxide at the "patient's mouth" personnel-related values remained clearly under the MAK-values. Outside the mainstream of the air-conditioning system the group "auxiliary nurse" had an approximately 30% higher exposure than the other groups. Under the described conditions, the working environment "operating room" can be classified as a low exposure working area.

  3. Operation of gas turbine engines in volcanic ash clouds

    SciTech Connect

    Dunn, M.G.; Baran, A.J.; Miatech, J.

    1996-10-01

    Results are reported for a technology program designed to determine the behavior of gas turbine engines when operating in particle-laden clouds. There are several ways that such clouds may be created, i.e., explosive volcanic eruption, sand storm, military conflict, etc. The response of several different engines, among them the Pratt and Whitney JT3D turbofan, the Pratt and Whitney J57 turbojet, a Pratt and Whitney engine of the JT9 vintage, and an engine of the General Electric CF6 vintage has been determined. The particular damage mode that will be dominant when an engine experiences a dust cloud depends upon the particular engine (the turbine inlet temperature at which the engine is operating when it encounters the dust cloud), the concentration of foreign material in the cloud, and the constituents of the foreign material (the respective melting temperature of the various constituents). Further, the rate at which engine damage will occur depends upon all of the factors given above, and the damage is cumulative with continued exposure. An important part of the Calspan effort has been to identify environmental warning signs and to determine which of the engine parameters available for monitoring by the flight crew can provide an early indication of impending difficulty. On the basis of current knowledge, if one knows the location of a particle-laden cloud, then that region should be avoided. However, if the cloud location is unknown, which is generally the case, then it is important to know how to recognize when an encounter has occurred and to understand how to operate safely, which is another part of the Calspan effort.

  4. Surface treatment of zinc anodes to improve discharge capacity and suppress hydrogen gas evolution

    NASA Astrophysics Data System (ADS)

    Cho, Yung-Da; Fey, George Ting-Kuo

    The shape change and redistribution of zinc anode material over the electrode during repeated cycling have been identified as the main factors that can limit the life of alkaline zinc-air batteries. Li 2O-2B 2O 3 (lithium boron oxide, LBO) glass with high Li + conductivity and stability can be coated on the surface of zinc powders. The structures of the surface-treated and pristine zinc powders were characterized by XRD, SEM, TEM, ESCA and BET analyses. XRD patterns of LBO-coated zinc powders revealed that the coating did not affect the crystal structure. TEM images of LBO-coated on the zinc particles were compact with an average passivation layer of about 250 nm. The LBO layer can prevent zinc from coming into direct contact with the KOH electrolyte and minimize the side reactions within the batteries. The 0.1 wt.% LBO-coated zinc anode material provided an initial discharge capacity of 1.70 Ah at 0.5 V, while the pristine zinc electrode delivered only 1.57 Ah. A surface-treated zinc electrode can increase discharge capacity, decrease hydrogen evolution reaction, and reduce self-discharge. The results indicated that surface treatment should be effective for improving the comprehensive properties of anode materials for zinc-air batteries.

  5. Laser flash-photolysis and gas discharge in N2O-containing mixture: kinetic mechanism

    NASA Astrophysics Data System (ADS)

    Kosarev, Ilya; Popov, Nikolay; Starikovskaia, Svetlana; Starikovskiy, Andrey; mipt Team

    2011-10-01

    The paper is devoted to further experimental and theoretical analysis of ignition by ArF laser flash-photolysis and nanosecond discharge in N2O-containing mixture has been done. Additional experiments have been made to assure that laser emission is distributed uniformly throughout the cross-section. The series of experiments was proposed and carried out to check validity of O(1D) determination in experiments on plasma assisted ignition initiated by flash-photolysis. In these experiments, ozone density in the given mixture (mixture composition and kinetics has been preliminary analyzed) was measured using UV light absorption in Hartley band. Good coincidence between experimental data and results of calculations have been obtained Temporal behavior of energy input, electric field and electric current has been measured and analyzed. These data are considered as initial conditions for numerical modeling of the discharge in O2:N2O:H2:Ar = 0.3:1:3:5 mixture. Ion-molecular reactions and reactions of active species production in Ar:H2:O2:N2O mixture were analyzed. The set of reactions to describe chemical transformation in the system due to the discharge action has been selected.

  6. 75 FR 29338 - Energy Efficiency of Natural Gas Infrastructure and Operations Conference; Final Notice of Public...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-25

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Energy Efficiency of Natural Gas Infrastructure and Operations Conference... . Kimberly D. Bose, Secretary. Federal Energy Regulatory Commission Energy Efficiency of Natural Gas...

  7. Electron density and gas density measurements in a millimeter-wave discharge

    SciTech Connect

    Schaub, S. C. Hummelt, J. S.; Guss, W. C.; Shapiro, M. A.; Temkin, R. J.

    2016-08-15

    Electron density and neutral gas density have been measured in a non-equilibrium air breakdown plasma using optical emission spectroscopy and two-dimensional laser interferometry, respectively. A plasma was created with a focused high frequency microwave beam in air. Experiments were run with 110 GHz and 124.5 GHz microwaves at powers up to 1.2 MW. Microwave pulses were 3 μs long at 110 GHz and 2.2 μs long at 124.5 GHz. Electron density was measured over a pressure range of 25 to 700 Torr as the input microwave power was varied. Electron density was found to be close to the critical density, where the collisional plasma frequency is equal to the microwave frequency, over the pressure range studied and to vary weakly with input power. Neutral gas density was measured over a pressure range from 150 to 750 Torr at power levels high above the threshold for initiating breakdown. The two-dimensional structure of the neutral gas density was resolved. Intense, localized heating was found to occur hundreds of nanoseconds after visible plasma formed. This heating led to neutral gas density reductions of greater than 80% where peak plasma densities occurred. Spatial structure and temporal dynamics of gas heating at atmospheric pressure were found to agree well with published numerical simulations.

  8. Electron density and gas density measurements in a millimeter-wave discharge

    SciTech Connect

    Schaub, S. C., E-mail: sschaub@mit.edu; Hummelt, J. S.; Guss, W. C.

    2016-08-15

    Electron density and neutral gas density have been measured in a non-equilibrium air breakdown plasma using optical emission spectroscopy and two-dimensional laser interferometry, respectively. A plasma was created with a focused high frequency microwave beam in air. Experiments were run with 110 GHz and 124.5 GHz microwaves at powers up to 1.2 MW. Microwave pulses were 3 μs long at 110 GHz and 2.2 μs long at 124.5 GHz. Electron density was measured over a pressure range of 25 to 700 Torr as the input microwave power was varied. Electron density was found to be close to the critical density, where the collisional plasma frequency is equal tomore » the microwave frequency, over the pressure range studied and to vary weakly with input power. Neutral gas density was measured over a pressure range from 150 to 750 Torr at power levels high above the threshold for initiating breakdown. The two-dimensional structure of the neutral gas density was resolved. Intense, localized heating was found to occur hundreds of nanoseconds after visible plasma formed. This heating led to neutral gas density reductions of greater than 80% where peak plasma densities occurred. Spatial structure and temporal dynamics of gas heating at atmospheric pressure were found to agree well with published numerical simulations.« less

  9. Aspects of the practical application of titanium alloys after low temperature nitriding glow discharge in hydrogen- free -gas media

    NASA Astrophysics Data System (ADS)

    Mashovets, N. S.; Pastukh, I. M.; Voloshko, S. M.

    2017-01-01

    X-ray diffraction analysis, X-ray photoelectron spectroscopy, and Electron Auger-spectroscopy investigation of phase transformation on the surface of the VT8 titanium alloy after a low temperature hydrogen-free nitriding in a glow discharge. Operational characteristics of titanium alloys defined physical-mechanical characteristics of the surface and their phase composition, which depend on the process parameters of nitriding. Surface modification of titanium alloys were carried out by low-temperature nitriding in a glow discharge in hydrogen-free environment. The main advantage of this method lies in the absence of hydrogen embrittlement and complete environmental safety process. Application of the glow discharge can not only speed up the process by the order of the diffusion surface saturation with nitrogen, but also significantly alters the kinetics of the process and quality of the nitrided layer, in particular its physio-mechanical properties and phase composition. For research purposes, the standards from an α + β alloy Ti-Al6-Cr2-Mo2,5 (VT8) were used. Research into the phase composition was performed by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Stratified analysis by AES was conducted by etching the surface of the samples' argon ion beam with diameters of 1.5 mm with an energy of 3000 eV and a current density of 400 mA/cm2. The above material shows the promise of the technology of low-temperature hydrogen-nitriding by glow discharge. This greatly expands the range of practical applications of titanium alloys. In addition, changing the technological mode allows you to manage a wide range of modified phase composition of the surface layer and as a result - to form the surface of titanium parts, taking into account the conditions of the subsequent operation.

  10. Gas-liquid separator and method of operation

    DOEpatents

    Soloveichik, Grigorii Lev [Latham, NY; Whitt, David Brandon [Albany, NY

    2009-07-14

    A system for gas-liquid separation in electrolysis processes is provided. The system includes a first compartment having a liquid carrier including a first gas therein and a second compartment having the liquid carrier including a second gas therein. The system also includes a gas-liquid separator fluidically coupled to the first and second compartments for separating the liquid carrier from the first and second gases.

  11. Electron Production, Electron Attachment, and Charge Recombination Process in High Pressure Gas Discharges.

    DTIC Science & Technology

    1984-09-17

    Associates: Dr. F. Li Dr. J. B. Nee Dr. W. C. Wang 3. Students: Mr. F. C. Clark Mr. J. S. Lai Mr. J. A. Marcrum Ms. M. Waxman S V. INTERACTIONS 1. The...Ar at E/N = 14.5 Td is shown in Figure la . The voltage decreases rapidly after the first peak, which is due to the loss of electrons by back... le -6- 5 less than the published data.5𔃼 5 Our data may be affected by the large electrical noise created by the laser discharge, so the uncertainty

  12. Electron Production, Electron Attachment, and Charge Recombination Process in High Pressure Gas Discharges

    DTIC Science & Technology

    1989-09-25

    Arias Ms. Lynn Dinh Mr. Zhiming Feng Mr. Allen Ho Mr. Shougin Huo Ms. Duyen P. Ly Mr. Salvador Plasencia Mr. John Spooner Ms. Kim Tran ,90925) 7 Appen...IEEE Trans . Plas. Sci. PS-15. 460 (1987). 7. "Electron Attachment Rate Constants of Bromine Compounds," W. C. Wang, D. P. Wang, and L. C. Lee, presented...Gaebe. "Negative ion kinetics in RF ghoa.discharges," IEEE Trans . Plahsma S’i.. al. PS-14. p. 92. 1986 can be controlled by changing laser beam size and

  13. Decomposition of acetaminophen in water by a gas phase dielectric barrier discharge plasma combined with TiO2-rGO nanocomposite: Mechanism and degradation pathway.

    PubMed

    Zhang, Guyu; Sun, Yabing; Zhang, Chunxiao; Yu, Zhongqing

    2017-02-05

    Acetaminophen (APAP) served as the model pollutant to evaluate the feasibility of pollutant removal by gas phase dielectric barrier discharge plasma combined with the titanium dioxide-reduced Graphene Oxide (TiO2-rGO) nanocomposite. TiO2-rGO nanocomposite was prepared using the modified hydrothermal method and characterized by TEM and XPS before and after plasma process. The results indicated that the APAP degradation efficiency was significantly improved to 92% after 18min of discharge plasma treatment coupling 0.25gL-1 TiO2-rGO 5%wt at 18kV, compared with the plasma alone and plasma combined with P25 TiO2. The degradation mechanism for APAP in this system was studied by investigating the effects of the operational variables (e.g. discharge voltage and pH value) and the amount of the generated active species; and the results showed that O3 and H2O2 yields were influenced notably by adding TiO2-rGO. Also, it was observed that, compared with unused TiO2-rGO, the photocatalytic performance of used TiO2-rGO declined after several recirculation times due to the further reduction of Graphene Oxide in plasma system. Finally, intermediate products were analyzed by UV-vis spectrometry and HPLC/MS, and possible transformation pathways were identified with the support of theoretically calculating the frontier electron density of APAP. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. 78 FR 59632 - Oil and Gas and Sulphur Operations on the Outer Continental Shelf-Oil and Gas Production Safety...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-27

    ... Bureau of Safety and Environmental Enforcement 30 CFR Part 250 RIN 1014-AA10 Oil and Gas and Sulphur Operations on the Outer Continental Shelf--Oil and Gas Production Safety Systems AGENCY: Bureau of Safety and...: Regulations Development Branch; 381 Elden Street, HE3313; Herndon, Virginia 20170-4817. Please reference ``Oil...

  15. Beams of fast neutral atoms and molecules in low-pressure gas-discharge plasma

    NASA Astrophysics Data System (ADS)

    Metel, A. S.

    2012-03-01

    Fast neutral atom and molecule beams have been studied, the beams being produced in a vacuum chamber at nitrogen, argon, or helium pressure of 0.1-10 Pa due to charge-exchange collisions of ions accelerated in the sheath between the glow discharge plasma and a negative grid immersed therein. From a flat grid, two broad beams of molecules with continuous distribution of their energy from zero up to e( U + U c ) (where U is voltage between the grid and the vacuum chamber and U c is cathode fall of the discharge) are propagating in opposite directions. The beam propagating from the concave surface of a 0.2-m-diameter grid is focused within a 10-mm-diameter spot on the target surface. When a 0.2-m-diameter 0.2-m-high cylindrical grid covered by end disks and composed of parallel 1.5-mm-diameter knitting needles spaced by 4.5 mm is immersed in the plasma, the accelerated ions pass through the gaps between the needles, turn inside the grid into fast atoms or molecules, and escape from the grid through the gaps on its opposite side. The Doppler shift of spectral lines allows for measuring the fast atom energy, which corresponds to the potential difference between the plasma inside the chamber and the plasma produced as a result of charge-exchange collisions inside the cylindrical grid.

  16. Validation of an analytical method for simultaneous high-precision measurements of greenhouse gas emissions from wastewater treatment plants using a gas chromatography-barrier discharge detector system.

    PubMed

    Pascale, Raffaella; Caivano, Marianna; Buchicchio, Alessandro; Mancini, Ignazio M; Bianco, Giuliana; Caniani, Donatella

    2017-01-13

    Wastewater treatment plants (WWTPs) emit CO 2 and N 2 O, which may lead to climate change and global warming. Over the last few years, awareness of greenhouse gas (GHG) emissions from WWTPs has increased. Moreover, the development of valid, reliable, and high-throughput analytical methods for simultaneous gas analysis is an essential requirement for environmental applications. In the present study, an analytical method based on a gas chromatograph (GC) equipped with a barrier ionization discharge (BID) detector was developed for the first time. This new method simultaneously analyses CO 2 and N 2 O and has a precision, measured in terms of relative standard of variation RSD%, equal to or less than 6.6% and 5.1%, respectively. The method's detection limits are 5.3ppm v for CO 2 and 62.0ppb v for N 2 O. The method's selectivity, linearity, accuracy, repeatability, intermediate precision, limit of detection and limit of quantification were good at trace concentration levels. After validation, the method was applied to a real case of N 2 O and CO 2 emissions from a WWTP, confirming its suitability as a standard procedure for simultaneous GHG analysis in environmental samples containing CO 2 levels less than 12,000mg/L. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Rydberg gas theory of a glow discharge plasma: III. Formation, occupied state distributions, free energy, and kinetic control.

    PubMed

    Mason, Rod S; Douglas, Peter

    2010-04-21

    It has been suggested that Rydberg gas atoms are involved in conducting electricity through a steady state flowing afterglow (FAG) discharge plasma (R. S. Mason, D. J. Mitchell and P. M. Dickinson, Phys. Chem. Chem. Phys., 2010, DOI: ). From known properties of Rydberg atoms, a statistical model is developed here to find the distribution of levels (principal quantum number n) occupied in such a hypothetical Rydberg gas. It behaves non-ideally at positive column plasma densities, predicting 30 < n < 150, peaking at n approximately = 85. These values depend on assumptions concerning the power of n dependency of 'pressure ionization' and the free charge density. The occupied states are very long-lived and almost completely separated from the low n states by the low probability of intermediate levels. The effects of Rydberg gas (N(R)) and free charge densities are examined. The gas can exist in a deep free energy well (> 120 kJ mol(-1) below ionisation level when 10(10) < or = N(R) < or = 10(11) atoms cm(-3)) but this is approximately 11 kJ mol(-1) higher than that of the equivalent free ion-electron gas; therefore if it exists in preference to the classical form of the plasma, it is controlled by kinetic factors. A mechanism is suggested by which this could occur. Thus, whilst ionization by high energy electron impact occurs at the Cathode Fall-Negative Glow (NG) boundary as usual, excitation of Rydberg atoms becomes more probable, by electrons slowed by collision and deceleration at the opposite NG-Positive Column (PC) plasma boundary. The atoms become stabilized after passing into the PC, by collisionally induced (nlm) mixing of states and the removal of free charge by charge transfer (and hence the passage of electric current through the Rydberg gas). The coupling of Rydberg states with the ionization continuum is poor; therefore, if the rate of their charge transfer is greater than that of their ionization, the Rydberg gas will remain relatively charge free and

  18. Penning Ionization Electron Spectroscopy in Glow Discharge: A New Dimension for Gas Chromatography Detectors

    NASA Technical Reports Server (NTRS)

    Sheverev, V. A.; Khromov, N. A.; Kojiro, D. R.; Fonda, Mark (Technical Monitor)

    2002-01-01

    Admixtures to helium of 100 ppm and 5 ppm of nitrogen, and 100 ppm and 10 ppm of carbon monoxide were identified and measured in the helium discharge afterglow using an electrical probe placed into the plasma. For nitrogen and carbon monoxide gases, the measured electron energy spectra display distinct characteristic peaks (fingerprints). Location of the peaks on the energy scale is determined by the ionization energies of the analyte molecules. Nitrogen and carbon monoxide fingerprints were also observed in a binary mixture of these gases in helium, and the relative concentration analytes has been predicted. The technically simple and durable method is considered a good candidate for a number of analytical applications, and in particular, in GC and for analytical flight instrumentation.

  19. Study of a contracted glow in low-frequency plasma-jet discharges operating with argon

    SciTech Connect

    Minotti, F.; Giuliani, L.; Xaubet, M.

    2015-11-15

    In this work, we present an experimental and theoretical study of a low frequency, atmospheric plasma-jet discharge in argon. The discharge has the characteristics of a contracted glow with a current channel of submillimeter diameter and a relatively high voltage cathode layer. In order to interpret the measurements, we consider the separate modeling of each region of the discharge: main channel and cathode layer, which must then be properly matched together. The main current channel was modeled, extending a previous work, as similar to an arc in which joule heating is balanced by lateral heat conduction, without thermal equilibrium betweenmore » electrons and heavy species. The cathode layer model, on the other hand, includes the emission of secondary electrons by ion impact and by additional mechanisms, of which we considered emission due to collision of atoms excited at metastable levels, and field-enhanced thermionic emission (Schottky effect). The comparison of model and experiment indicates that the discharge can be effectively sustained in its contracted form by the secondary electrons emitted by collision of excited argon atoms, whereas thermionic emission is by far insufficient to provide the necessary electrons.« less

  20. 33 CFR 151.79 - Operating requirements: Discharge of sewage within Antarctica.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... on Environmental Protection to the Antarctic Treaty as it Pertains to Pollution from Ships Garbage... be discharged instantaneously but at a moderate rate and, where practicable, while the ship is en... from spaces containing living animals; or (4) Other waste waters when mixed with the drainages defined...

  1. 33 CFR 151.79 - Operating requirements: Discharge of sewage within Antarctica.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... on Environmental Protection to the Antarctic Treaty as it Pertains to Pollution from Ships Garbage... be discharged instantaneously but at a moderate rate and, where practicable, while the ship is en... from spaces containing living animals; or (4) Other waste waters when mixed with the drainages defined...

  2. 33 CFR 151.79 - Operating requirements: Discharge of sewage within Antarctica.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... on Environmental Protection to the Antarctic Treaty as it Pertains to Pollution from Ships Garbage... be discharged instantaneously but at a moderate rate and, where practicable, while the ship is en... from spaces containing living animals; or (4) Other waste waters when mixed with the drainages defined...

  3. 33 CFR 151.73 - Operating requirements: Discharge of garbage from fixed or floating platforms.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION VESSELS CARRYING OIL, NOXIOUS LIQUID SUBSTANCES, GARBAGE, MUNICIPAL OR COMMERCIAL WASTE, AND BALLAST WATER Implementation of MARPOL 73/78 and the... waste may be discharged into the sea from a ship or fixed or floating platform regulated by paragraph (a...

  4. 76 FR 67177 - Pacific Gas and Electric Company; California Independent System Operator Corporation; Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-31

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Pacific Gas and Electric Company; California Independent System Operator... California Independent System Operator Corporation (Respondent), alleging that the application of certain...

  5. Sr Isotope Quantification of Deep Brine and Shallow Acidic Coal Mine Drainage Inputs to High TDS Gas Well Discharges in Western Pennsylvania

    NASA Astrophysics Data System (ADS)

    Chapman, E.; Capo, R.; Stewart, B. W.; Hedin, R.; Weaver, T.

    2009-12-01

    Chapman, E. C., Capo. R. C., Stewart, B. W. Dept. of Geology & Planetary Science, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260 Hedin, R. S. and Weaver, T. R., Hedin Environmental, 195 Castle Shannon Blvd., Pittsburgh, Pennsylvania, 15228 In western Pennsylvania, numerous abandoned oil and gas wells discharge contaminated water to the surface. Many of these discharges have circumneutral pH as well as high concentrations of iron and sulfate. Total dissolved solid (TDS) content is also high relative to local groundwater. Possible sources of this water include deep brines, which have circumneutral pH and very high TDS, or shallow acidic coal mine drainage (AMD). Hundreds of hilltop strip mines are found in this area, and mine seeps have low pH (3.5-4) and high TDS. Geochemical data alone have not been definitive in determining the source of the gas well discharges. Strontium isotopic compositions of deep brine, gas well discharges drilled 150-240 m deep into Upper Devonian strata, and local AMD associated with the Leeper anticline in Clarion County strongly suggest that the water chemistry in the gas wells is dominated (>99%) by mine drainage. Because of its high Sr concentrations, even small contributions of brine (<1%) can significantly change the 87Sr/86Sr of the groundwater. With the ability to determine the source of these discharges, other questions about subsurface geochemical reactions can be addressed. For example, iron concentration in the gas well discharges is much higher than either the deep brines or shallow AMD. This could be due to siderite (FeCO3) dissolution by AMD; previous work identified the presence of siderite in sedimentary strata within the subsurface path of the AMD flows. Carbonate mineral dissolution could also explain the circumneutral pH of flows from the gas wells. Sr isotopes can be used as a sensitive tracer for the interaction of shallow and deep fossil fuel byproducts with natural waters, including produced waters from

  6. Study of the prebreakdown stage of a gas discharge in a diode with point cathode by laser probing

    NASA Astrophysics Data System (ADS)

    Parkevich, E. V.; Tkachenko, S. I.; Agafonov, A. V.; Mingaleev, A. R.; Romanova, V. M.; Shelkovenko, T. A.; Pikuz, S. A.

    2017-04-01

    The prebreakdown stage of a gas discharge in a diode with strongly overloaded cathode is studied by laser methods (by simultaneous use of multiframe interferometry and shadow and schlieren photographing) at atmospheric pressure. The spatial resolution of the methods is about 20 μm. A probing pulse of a laser (LS-2151 Nd: YAG laser with a half amplitude duration of 70 ps and a pulse energy of up to 40 mJ) is synchronized with a voltage pulse with accuracy of about 1 ns. High field strength at the cathode is achieved due to the use of thin individual metal tips on the electrodes. It is shown that the initial stage of breakdown of a discharge gap is accompanied by the emergence of a dense plasma cloud at the end of a tip with electron density of about 5 × 1019 cm-3 with a size of tens of microns, as well as by a sharp increase in the total current through the diode. After the emergence of a dense plasma cloud at the end of a cathode tip, a similar cloud is formed on the surface of the anode; sometime later, these clouds join together and form a tubular current channel. The dynamics of the breakdown, as well as the parameters of the plasma are studied by the abovementioned techniques in three independent optical channels.

  7. The simplest equivalent circuit of a pulsed dielectric barrier discharge and the determination of the gas gap charge transfer

    NASA Astrophysics Data System (ADS)

    Pipa, A. V.; Koskulics, J.; Brandenburg, R.; Hoder, T.

    2012-11-01

    The concept of the simplest equivalent circuit for a dielectric barrier discharge (DBD) is critically reviewed. It is shown that the approach is consistent with experimental data measured either in large-scale sinusoidal-voltage driven or miniature pulse-voltage driven DBDs. An expression for the charge transferred through the gas gap q(t) is obtained with an accurate account for the displacement current and the values of DBD reactor capacitance. This enables (i) the significant reduction of experimental error in the determination of q(t) in pulsed DBDs, (ii) the verification of the classical electrical theory of ozonizers about maximal transferred charge qmax, and (iii) the development of a graphical method for the determination of qmax from charge-voltage characteristics (Q-V plots, often referred as Lissajous figures) measured under pulsed excitation. The method of graphical presentation of qmax is demonstrated with an example of a Q-V plot measured under pulsed excitation. The relations between the discharge current jR(t), the transferred charge q(t), and the measurable parameters are presented in new forms, which enable the qualitative interpretation of the measured current and voltage waveforms without the knowledge about the value of the dielectric barrier capacitance Cd. Whereas for quantitative evaluation of electrical measurements, the accurate estimation of the Cd is important.

  8. Optical characteristics and parameters of gas-discharge plasma in a mixture of mercury dibromide vapor with argon

    SciTech Connect

    Malinina, A. A., E-mail: alexandr-malinin@rambler.ru; Malinin, A. N.

    2015-03-15

    Results are presented from studies of the optical characteristics and parameters of the plasma of a dielectric barrier discharge in a mixture of mercury dibromide vapor with argon—the working medium of an exciplex gas-discharge emitter. It is established that the partial pressures of mercury dibromide vapor and argon at which the average and pulsed emission intensities in the blue—green spectral region (λ{sub max} = 502 nm) reach their maximum values are 0.6 and 114.4 kPa, respectively. The electron energy distribution function, the transport characteristics, the specific power spent on the processes involving electrons, the electron density and temperature, and themore » rate constants for the processes of elastic and inelastic electron scattering from the molecules and atoms of the working mixture are determined by numerical simulation, and their dependences on the reduced electric field strength are analyzed. The rate constant of the process leading to the formation of exciplex mercury monobromide molecules for a reduced electric field of E/N = 20 Td, at which the maximum emission intensity in the blue—green spectral region was observed in this experiment, is found to be 8.1 × 10{sup −15} m{sup 3}/s.« less

  9. Optical characteristics and parameters of gas-discharge plasma in a mixture of mercury dibromide vapor with argon

    SciTech Connect

    Malinina, A. A. Malinin, A. N.

    2015-03-15

    Results are presented from studies of the optical characteristics and parameters of the plasma of a dielectric barrier discharge in a mixture of mercury dibromide vapor with argon—the working medium of an exciplex gas-discharge emitter. It is established that the partial pressures of mercury dibromide vapor and argon at which the average and pulsed emission intensities in the blue—green spectral region (λ{sub max} = 502 nm) reach their maximum values are 0.6 and 114.4 kPa, respectively. The electron energy distribution function, the transport characteristics, the specific power spent on the processes involving electrons, the electron density and temperature, and the rate constants for the processes of elastic and inelastic electron scattering from the molecules and atoms of the working mixture are determined by numerical simulation, and their dependences on the reduced electric field strength are analyzed. The rate constant of the process leading to the formation of exciplex mercury monobromide molecules for a reduced electric field of E/N = 20 Td, at which the maximum emission intensity in the blue—green spectral region was observed in this experiment, is found to be 8.1 × 10{sup −15} m{sup 3}/s.

  10. Recent Operational Experience with the Internal Thermal Control System Dual-Membrane Gas Trap

    NASA Technical Reports Server (NTRS)

    Leimkuehler, Thomas O.; Lukens, Clark; Reeves, Daniel R.; Holt, James M.

    2004-01-01

    A dual-membrane gas trap is currently used to remove gas bubbles from the Internal Thermal Control System (ITCS) coolant on board the International Space Station. The gas trap consists of concentric tube membrane pairs, comprised of outer hydrophilic tubes and inner hydrophobic fibers. Liquid coolant passes through the outer hydrophilic membrane, which traps the gas bubbles. The inner hydrophobic fiber allows the trapped gas bubbles to pass through and vent to the ambient atmosphere in the cabin. The gas removal performance and operational lifetime of the gas trap have been affected by contamination in the ITCS coolant. However, the gas trap has performed flawlessly with regard to its purpose of preventing gas bubbles from causing depriming, overspeed, and shutdown of the ITCS pump. This paper discusses on-orbit events over the course of the last year related to the performance and functioning of the gas trap.

  11. Mastectomy - discharge

    MedlinePlus

    Breast removal surgery - discharge; Nipple-sparing mastectomy - discharge; Total mastectomy - discharge; Simple mastectomy - discharge; Modified radical mastectomy - discharge; Breast cancer - mastectomy -discharge

  12. TEST RESULTS FOR FUEL-CELL OPERATION ON LANDFILL GAS

    EPA Science Inventory

    Test results from a demonstration of fuel-cell (FC) energy recovery and control of landfill gas emissions are presented. The project addressed two major issues: (i) the design, construction, and testing of a landfill-gas cleanup system; and (ii) a field test of a commercial phos...

  13. Internal combustion engine for natural gas compressor operation

    SciTech Connect

    Hagen, Christopher L.; Babbitt, Guy; Turner, Christopher

    2016-04-19

    This application concerns systems and methods for compressing natural gas with an internal combustion engine. In a representative embodiment, a system for compressing a gas comprises a reciprocating internal combustion engine including at least one piston-cylinder assembly comprising a piston configured to travel in a cylinder and to compress gas in the cylinder in multiple compression stages. The system can further comprise a first pressure tank in fluid communication with the piston-cylinder assembly to receive compressed gas from the piston-cylinder assembly until the first pressure tank reaches a predetermined pressure, and a second pressure tank in fluid communication with themore » piston-cylinder assembly and the first pressure tank. The second pressure tank can be configured to receive compressed gas from the piston-cylinder assembly until the second pressure tank reaches a predetermined pressure. When the first and second pressure tanks have reached the predetermined pressures, the first pressure tank can be configured to supply gas to the piston-cylinder assembly, and the piston can be configured to compress the gas supplied by the first pressure tank such that the compressed gas flows into the second pressure tank.« less

  14. Internal combustion engine for natural gas compressor operation

    DOEpatents

    Hagen, Christopher L.; Babbitt, Guy; Turner, Christopher; Echter, Nick; Weyer-Geigel, Kristina

    2016-04-19

    This application concerns systems and methods for compressing natural gas with an internal combustion engine. In a representative embodiment, a system for compressing a gas comprises a reciprocating internal combustion engine including at least one piston-cylinder assembly comprising a piston configured to travel in a cylinder and to compress gas in the cylinder in multiple compression stages. The system can further comprise a first pressure tank in fluid communication with the piston-cylinder assembly to receive compressed gas from the piston-cylinder assembly until the first pressure tank reaches a predetermined pressure, and a second pressure tank in fluid communication with the piston-cylinder assembly and the first pressure tank. The second pressure tank can be configured to receive compressed gas from the piston-cylinder assembly until the second pressure tank reaches a predetermined pressure. When the first and second pressure tanks have reached the predetermined pressures, the first pressure tank can be configured to supply gas to the piston-cylinder assembly, and the piston can be configured to compress the gas supplied by the first pressure tank such that the compressed gas flows into the second pressure tank.

  15. Stabilized gas-discharge laser with an external absorption cell in the gain-modulation regime

    NASA Astrophysics Data System (ADS)

    Mironov, A. V.; Privalov, V. E.

    1982-05-01

    A theoretical analysis is presented of the frequency shift of a gas laser stabilized by absorption in an external cell; the shift is caused by gain modulation and parasitic (environmentally determined) frequency modulation effects on the frequency locking system. In the case of combined gain and frequency modulation, the shift occurs not only when the frequencies of perturbations coincide with harmonics of the reference signal of the locking system, but also at combinational frequencies. For this reason, an analysis of frequency fluctuations which takes separate account of gain and frequency perturbations is inadequate. The instability of the scale factor of a ring laser stabilized by an external cell is investigated.

  16. A Chemical Detector for Gas Chromatography Using Pulsed Discharge Emission Spectroscopy on a Microchip

    NASA Astrophysics Data System (ADS)

    Luo, X.; Zhu, W.; Mitra, B.; Liu, J.; Liu, T.; Fan, X.; Gianchandani, Y.

    2011-12-01

    There is increasing interest in miniaturized systems for chemical analysis in harsh environments. Chemical detection by emission spectroscopy of on-chip microdischarges [1-3] can be performed at >200°C [4], suggesting utility inspace exploration, volcanic monitoring, and oil well monitoring. This abstract describes the first use of pulsed microdischarge spectroscopy for gas chromatography (GC).This effort supports NASA interests in monitoring closed-loop life support systems for spacecraft. The microdischarge occurs on a 1cm2 glass chip (Fig. 1a), with thin-film Ni electrodes separated by 160μm. A glass lid with a grooved gas-flow channel, and inlet/outlet capillary tubes are epoxy-sealed to the chip. Located downstream of the 1.7m-long, RTX-1-coated, GC separation column, the microdischarge chip is read by a spectrometer. In a typical experiment (Fig. 1b), a mixture of acetone 3.6μg, 1-hexanol 2.8μg and nitrobenzene 3.0μg, is injected, with He carrier gas at 1.56sccm, through the GC. Acetone elutes quickly while nitrobenzene is slower. Microdischarges are triggered at 0.5Hz for 6 min., and 0.04Hz thereafter. Each microdischarge consumes ≈8mJ; the average power is ≈1.14mW. The spectrum (Fig. 1b, inset) shows that the 388nm peak, representing CN/CH fragments [5], is enhanced by carbon compounds. Its strength relative to the 588nm peak of He provides a chromatogram. Fig. 1b also shows a benchmark result from a commercial flame ionization detector (FID). The differences in elution time are attributed to differences in the gas flow paths for the two detectors [1]. REFERENCES [1] Eijkel et al, Anal. Chem, 2000 [2] Mitra et al, IEEE Trans Plasma Sci, 2008 [3] Mitra et al, IEEE Sensors, 2008 [4] Wright et al, APL, 2009 [5] Pearse et al, The Identification of Molecular Spectra, 1963

  17. Greenhouse gas emissions are enhanced by wastewater discharge into New York City coastal estuaries

    NASA Astrophysics Data System (ADS)

    Brigham, B. A.; O'Mullan, G. D.; Bird, J. A.

    2016-12-01

    The Hudson River Estuary (HRE) receives significant inputs of untreated wastewater from sewer overflow from New York City (NYC) and other urban areas. These inputs deliver large, concentrated pulses of carbon (C) and nitrogen (N) into the estuary primarily during storm events. We hypothesized that sewage inputs would increase carbon dioxide (CO2) and methane (CH4) efflux from the HRE via two mechanism: (1) direct input of these gases into estuarine surface waters from NYC's wastewater treatment system; and (2) indirect in-situ microbial production in response to the C and N additions. To test these hypotheses, CO2, CH4, dissolved organic C and inorganic N concentrations were measured in both sewage outflow and in estuarine waters. Efflux of CO2 and CH4 were also quantified from sediment cores sampled from Flushing Bay (FB), which is in close proximity to sewage delivery outlets. Wastewater discharge was found to be both a direct input in wastewater and an indirect source of CO2 and CH4 via microbial respiration. Effluent concentrations of CH4 (125 ppm), CO2 (2200 ρCO2), dissolved organic C, ammonium, and nitrate surface water concentrations, were a minimum of 3 times greater than in estuarine surface water adjacent to the sewage delivery area and up to 20 times greater than concentrations found in regional HRE surface waters. Incubation experiments with FB sediment demonstrated that acetate additions stimulated CO2 efflux by + 1.25 and CH4 efflux by +10 times, compared with unamended controls. The magnitude of CH4 produced was +40 times greater than from sediments incubated from a non-sewage affected area with similar salinity levels. However, total C mineralization (6 µg C day-1 g-1 of dry soil) was a small portion of the C amendment indicating negligible priming. These data warrant study on larger regional scales to assess the broader climate impact likely driven by CH4 efflux that results from discharge of untreated wastewater into urban estuaries.

  18. Effect of air flow on the micro-discharge dynamics in an array of integrated coaxial microhollow dielectric barrier discharges

    NASA Astrophysics Data System (ADS)

    Nayak, Gaurav; Du, Yanjun; Brandenburg, Ronny; Bruggeman, Peter J.

    2017-03-01

    The micro-discharge properties and evolution in a 2D array of integrated coaxial microhollow dielectric barrier discharges are studied by using highly time-resolved electrical and optical diagnostics. The study is focused on the effect of the gas flow rate and gas residence time on discharge properties. The investigated integrated coaxial microhollow discharge geometry allows operating the discharge at exceptionally small residence times, which can be equal to or even smaller than the discharge period, at reasonable gas flow rates. The gas flow has an impact on gas heating, residual humidity, pre-ionization density and the densities of excited and reactive species produced by previous discharges. A unique voltage-charge plot is obtained with elongated periods without discharge activity. A very significant effect of flow on NO emission is observed that relates to the impact of flow on the NO production in these micro-discharges. Using the emission intensities of molecular bands of the second positive system of nitrogen and the first negative system of the nitrogen ion, effective reduced electric field strengths are obtained with a maximum equal to 870 Td. The reduced electric field decreases with increasing gas flow rate. This behavior is consistent with the reduction of the overall discharge intensity due to a reduced amount of charges present in the discharge gap. Both the flow rate and a reduction in water impurity changing the ion mobility can be responsible for the different effective electric field distributions at the highest and no flow conditions.

  19. Abatement of toluene from gas streams via ferro-electric packed bed dielectric barrier discharge plasma.

    PubMed

    Liang, Wenjun; Li, Jian; Li, Jie; Jin, Yuquan

    2009-10-30

    Destruction of gaseous toluene via ferro-electric packed bed dielectric barrier discharge plasma in a coaxial cylindrical reactor was carried out at atmospheric pressure and room temperature. The difference among three kinds of reactors was compared in terms of specific energy density (SED), energy yield (EY), toluene decomposition. In order to optimize the geometry of the reactor, the removal efficiency of toluene was compared for various inner electrode diameters. In addition, qualitative analysis on by-products and particular discussion on toluene abatement mechanisms were also presented. It has been found that ferro-electric packed bed DBD reactor could effectively decompose toluene. Toluene removal efficiency enhanced with increasing SED. With respect to toluene conversion, 1.62 mm electrode appeared to be superior to 1.06 mm electrodes. BaTiO3 reactor had the highest toluene removal efficiency among the reactors. For NaNO2 reactor, the highest EY could reach 17.0 mg/kWh to a certain extent.

  20. High frequency excitation waveform for efficient operation of a xenon excimer dielectric barrier discharge lamp

    NASA Astrophysics Data System (ADS)

    Beleznai, Sz; Mihajlik, G.; Maros, I.; Balázs, L.; Richter, P.

    2010-01-01

    The application of a high frequency (~2.5 MHz) burst (amplitude-modulated sinusoidal) excitation voltage waveform is investigated for driving a fluorescent dielectric barrier discharge (DBD) light source. The excitation waveform presents a novel method for generating spatially stable homogeneous Xe DBD possessing a high conversion efficiency from electrical energy to VUV Xe_{2}^{\\ast} excimer radiation (~172 nm), even at a significantly higher electrical energy deposition than realized by pulsed excitation. Simulation and experimental results predict discharge efficiencies around 60%. Lamp efficacy above 74 lm W-1 has been achieved. VUV emission and loss mechanisms are investigated extensively and the performance of burst and pulsed waveforms is compared both theoretically and experimentally.

  1. Purge gas protected transportable pressurized fuel cell modules and their operation in a power plant

    DOEpatents

    Zafred, P.R.; Dederer, J.T.; Gillett, J.E.; Basel, R.A.; Antenucci, A.B.

    1996-11-12

    A fuel cell generator apparatus and method of its operation involves: passing pressurized oxidant gas and pressurized fuel gas into modules containing fuel cells, where the modules are each enclosed by a module housing surrounded by an axially elongated pressure vessel, and where there is a purge gas volume between the module housing and pressure vessel; passing pressurized purge gas through the purge gas volume to dilute any unreacted fuel gas from the modules; and passing exhaust gas and circulated purge gas and any unreacted fuel gas out of the pressure vessel; where the fuel cell generator apparatus is transportable when the pressure vessel is horizontally disposed, providing a low center of gravity. 11 figs.

  2. Purge gas protected transportable pressurized fuel cell modules and their operation in a power plant

    DOEpatents

    Zafred, Paolo R.; Dederer, Jeffrey T.; Gillett, James E.; Basel, Richard A.; Antenucci, Annette B.

    1996-01-01

    A fuel cell generator apparatus and method of its operation involves: passing pressurized oxidant gas, (O) and pressurized fuel gas, (F), into fuel cell modules, (10 and 12), containing fuel cells, where the modules are each enclosed by a module housing (18), surrounded by an axially elongated pressure vessel (64), where there is a purge gas volume, (62), between the module housing and pressure vessel; passing pressurized purge gas, (P), through the purge gas volume, (62), to dilute any unreacted fuel gas from the modules; and passing exhaust gas, (82), and circulated purge gas and any unreacted fuel gas out of the pressure vessel; where the fuel cell generator apparatus is transpatable when the pressure vessel (64) is horizontally disposed, providing a low center of gravity.

  3. Clean air program : liquefied natural gas safety in transit operations

    DOT National Transportation Integrated Search

    1996-03-31

    The report examines the safety issues relating to the use of Liquefied Natural Gas (LNG) in transit service. The safety issues were determined by on-site surveys performed by Battelle of Columbus, Ohio, and Science Applications International Corp. (S...

  4. Data collection system for a wide range of gas-discharge proportional neutron counters

    NASA Astrophysics Data System (ADS)

    Oskomov, V.; Sedov, A.; Saduyev, N.; Kalikulov, O.; Kenzhina, I.; Tautaev, E.; Mukhamejanov, Y.; Dyachkov, V.; Utey, Sh

    2017-12-01

    This article describes the development and creation of a universal system of data collection to measure the intensity of pulsed signals. As a result of careful analysis of time conditions and operating conditions of software and hardware complex circuit solutions were selected that meet the required specifications: frequency response is optimized in order to obtain the maximum ratio signal/noise; methods and modes of operation of the microcontroller were worked out to implement the objectives of continuous measurement of signal amplitude at the output of amplifier and send the data to a computer; function of control of high voltage source was implemented. The preliminary program has been developed for microcontroller in its simplest form, which works on a particular algorithm.

  5. Internal combustion engine for natural gas compressor operation

    SciTech Connect

    Hagen, Christopher; Babbitt, Guy

    2016-12-27

    This application concerns systems and methods for compressing natural gas with an internal combustion engine. In a representative embodiment, a method is featured which includes placing a first cylinder of an internal combustion engine in a compressor mode, and compressing a gas within the first cylinder, using the cylinder as a reciprocating compressor. In some embodiments a compression check valve system is used to regulate pressure and flow within cylinders of the engine during a compression process.

  6. Scrubbing process and chemical equilibria controlling the composition of light hydrocarbons in natural gas discharges: An example from the geothermal fields of El Salvador

    NASA Astrophysics Data System (ADS)

    Tassi, F.; Vaselli, O.; Capaccioni, B.; Montegrossi, G.; Barahona, F.; Caprai, A.

    2007-05-01

    The compositional features of fluids from both fumarolic discharges and productive geothermal wells of Ahuachapan-Chipilapa, Berlin-Chinameca, and San Vicente geothermal systems (El Salvador) are described and discussed in order to investigate the complex geochemical interactions involving geothermal fluids within the shallowest part of the hydrothermal circulation pathways. Our results highlight that secondary processes are able to strongly affect and modify the chemical characteristics of geothermal gases once they discharge to the surface as natural manifestations, mainly in relation to the chemical-physical properties of each gas species. The effects of both gas dissolution in shallow aquifers and gas-water-rock chemical interactions on gas discharge composition make it difficult to get a correct evaluation of the thermodynamic conditions that characterize the geothermal reservoirs by applying the common geoindicators based on the chemical equilibria of the H2O-CO2-H2-CH4-CO system. Differently, the composition of the C1-C2-C3 alkanes and the C3 and C4 alkane-alkene pair, established within the geothermal reservoirs under the control of chemical reactions, remains stable in samples collected from discharging gas vents. These results suggest that the relative abundances of hydrocarbons characterized by similar structure and molecular size seem to be mainly regulated by the diffusion velocity of gases through the liquid-dominated system. Therefore the chemical features of the light organic gas fraction of naturally discharging fluids can be successfully utilized for the evaluation of geothermal reservoir temperatures and redox conditions, providing useful indications in terms of geothermal exploration and exploitation. On this basis, the distribution, speciation, and relative abundances of light hydrocarbons can also be considered highly promising in geochemical monitoring of active volcanic systems.

  7. Effect of wastewater discharge on greenhouse gas fluxes from mangrove soils

    NASA Astrophysics Data System (ADS)

    Chen, G. C.; Tam, N. F. Y.; Wong, Y. S.; Ye, Y.

    2011-02-01

    The effects of wastewater on atmospheric fluxes of three greenhouse gases, nitrous oxide (N 2O), methane (CH 4) and carbon dioxide (CO 2) from mangrove soils were investigated, and the differences among shrimp pond wastewater (SP), livestock wastewater (LS) and municipal (S) sewage were compared. The gas emissions from mangrove soils were significantly enhanced after wastewater irrigation and the highest emission of N 2O and CO 2 were obtained from SP. High N 2O emission was also found in S treatment, where fluxes varied from 13.42 to 16.78 μmol m -2 h -1, but the CH 4 and CO 2 fluxes were as low as the control irrigated with tap water. Results of soil analyses indicated that the high N 2O emissions from mangrove soils receiving SP and S treatments were attributed to the denitrification and nitrification processes, respectively. The highest CH 4 flux was recorded in LS treatment (186.14-762.40 μmol m -2 h -1), which also had the highest CO 2 flux. The fluxes measured during the non-irrigation period were lower than those measured 4 h after irrigation.

  8. Development of SSUBPIC code for modeling the neutral gas depletion effect in helicon discharges

    NASA Astrophysics Data System (ADS)

    Kollasch, Jeffrey; Sovenic, Carl; Schmitz, Oliver

    2017-10-01

    The SSUBPIC (steady-state unstructured-boundary particle-in-cell) code is being developed to model helicon plasma devices. The envisioned modeling framework incorporates (1) a kinetic neutral particle model, (2) a kinetic ion model, (3) a fluid electron model, and (4) an RF power deposition model. The models are loosely coupled and iterated until convergence to steady-state. Of the four required solvers, the kinetic ion and neutral particle simulation can now be done within the SSUBPIC code. Recent SSUBPIC modifications include implementation and testing of a Coulomb collision model (Lemons et al., JCP, 228(5), pp. 1391-1403) allowing efficient coupling of kineticly-treated ions to fluid electrons, and implementation of a neutral particle tracking mode with charge-exchange and electron impact ionization physics. These new simulation capabilities are demonstrated working independently and coupled to ``dummy'' profiles for RF power deposition to converge on steady-state plasma and neutral profiles. The geometry and conditions considered are similar to those of the MARIA experiment at UW-Madison. Initial results qualitatively show the expected neutral gas depletion effect in which neutrals in the plasma core are not replenished at a sufficient rate to sustain a higher plasma density. This work is funded by the NSF CAREER award PHY-1455210 and NSF Grant PHY-1206421.

  9. Surface modification and stability of detonation nanodiamonds in microwave gas discharge plasma

    NASA Astrophysics Data System (ADS)

    Stanishevsky, Andrei V.; Walock, Michael J.; Catledge, Shane A.

    2015-12-01

    Detonation nanodiamonds (DND), with low hydrogen content, were exposed to microwave plasma generated in pure H2, N2, and O2 gases and their mixtures, and investigated using X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), Raman, and X-ray photoelectron spectroscopies. Considerable alteration of the DND surface was observed under the plasma conditions for all used gases, but the diamond structure of the DND particle core was preserved in most cases. The stabilizing effect of H2 in H2/N2 and H2/O2 binary gas plasmas on the DND structure and the temperature-dependent formation of various CNHx surface groups in N2 and H2/N2 plasmas were observed and discussed for the first time. DND surface oxidation and etching were the main effects of O2 plasma, whereas the N2 plasma led to DND surfaces rich in amide groups below 1073 K and nitrile groups at higher temperatures. Noticeable graphitization of the DND core structure was detected only in N2 plasma when the substrate temperature was above 1103 K.

  10. About the development of single microdischarges in dielectric barrier discharges in CO2 and CO2/N2 gas mixtures. DBD-MDs in CO2 and CO2/N2

    NASA Astrophysics Data System (ADS)

    Brandenburg, Ronny; Sarani, Abdollah

    2017-08-01

    The conversion of carbon dioxide as one of the main greenhouse gases into carbon monoxide as a chemical feedstock is considered as so-called carbon capture usage technology. Recently it was shown, that the dissociation of carbon dioxide to carbon monoxide in Dielectric Barrier Discharges can be enhanced by the addition of nitrogen gas. Here, the development of microdischarges in CO2 and CO2/N2 gas mixtures is studied. Therefore, a single filament DBD arrangement operated under sinusoidal high-voltage is investigated by means of spectroscopic and electrical diagnostics with high spatial and temporal resolution and sensitivity. The filament development is similar as in air or other nitrogen-oxygen gas mixtures, but the gas composition influences the duration and other parameters. The higher the CO2 content the weaker the filaments and the faster the quenching of excited molecular states. The optimum power dissipation into single discharge is obtained for a CO2 content between 20 and 30 vol.%.

  11. Review of Well Operator Files for Hydraulically Fractured Oil and Gas Production Wells: Hydraulic Fracturing Operations

    EPA Pesticide Factsheets

    EPA conducted a survey of oil and gas production wells hydraulically fractured by nine oil and gas service companies in the United States during 2009 and 2010. This is the second well file review report.

  12. TECHNOLOGIES TO ENHANCE OPERATION OF THE EXISTING NATURAL GAS COMPRESSION INFRASTRUCTURE

    SciTech Connect

    Anthony J. Smalley; Ralph E. Harris; Gary D. Bourn

    2004-08-01

    This report documents work performed in Phase I of the project entitled: ''Technologies to Enhance Operation of the Existing Natural Gas Compression Infracture''. The project objective is to develop and substantiate methods for operating integral engine/compressors in gas pipeline service, which reduce fuel consumption, increase capacity, and enhance mechanical integrity. The report describes a number of potential enhancements to the existing natural gas compression infrastructure that have been identified and tested on four different integral engine/compressors in natural gas transmission service.

  13. TECHNOLOGIES TO ENHANCE OPERATION OF THE EXISTING NATURAL GAS COMPRESSION INFRASTRUCTURE

    SciTech Connect

    Anthony J. Smalley; Ralph E. Harris; Gary D. Bourn

    2004-03-01

    This report documents work performed in Phase I of the project entitled: ''Technologies to Enhance Operation of the Existing Natural Gas Compression Infrastructure''. The project objective is to develop and substantiate methods for operating integral engine/compressors in gas pipeline service, which reduce fuel consumption, increase capacity, and enhance mechanical integrity. The report describes a number of potential enhancements to the existing natural gas compression infrastructure that have been identified and qualitatively demonstrated in tests on three different integral engine/compressors in natural gas transmission service.

  14. TEST RESULTS FOR FUEL CELL OPERATION ON ANAEROBIC DIGESTER GAS

    EPA Science Inventory

    EPA, in conjunction with ONSI Corp., embarked on a project to define, design, test, and assess a fuel cell energy recovery system for application at anaerobic digester waste water (sewage) treatment plants. Anaerobic digester gas (ADG) is produced at these plants during the proce...

  15. Mechanical Properties of Gas Shale During Drilling Operations

    NASA Astrophysics Data System (ADS)

    Yan, Chuanliang; Deng, Jingen; Cheng, Yuanfang; Li, Menglai; Feng, Yongcun; Li, Xiaorong

    2017-07-01

    The mechanical properties of gas shale significantly affect the designs of drilling, completion, and hydraulic fracturing treatments. In this paper, the microstructure characteristics of gas shale from southern China containing up to 45.1% clay were analyzed using a scanning electron microscope. The gas shale samples feature strongly anisotropic characteristics and well-developed bedding planes. Their strength is controlled by the strength of both the matrix and the bedding planes. Conventional triaxial tests and direct shear tests are further used to study the chemical effects of drilling fluids on the strength of shale matrix and bedding planes, respectively. The results show that the drilling fluid has a much larger impact on the strength of the bedding plane than that of the shale matrix. The impact of water-based mud (WBM) is much larger compared with oil-based mud. Furthermore, the borehole collapse pressure of shale gas wells considering the effects of drilling fluids are analyzed. The results show that the collapse pressure increases gradually with the increase of drilling time, especially for WBM.

  16. The critical electric field of gas mixtures over the extended range of cryogenic operating conditions

    NASA Astrophysics Data System (ADS)

    Park, Chanyeop; Pamidi, Sastry; Graber, Lukas

    2017-10-01

    In this study, we provide the critical electric field and dielectric strength of cryogenic gas mixtures over an extended cryogenic temperature and pressure range that covers most of the operating conditions of superconducting applications. For gas-cooled cryogenic systems, condensation must not occur during operation. To prevent condensation, we determine the maximum allowed mole fractions of gas species consisting cryogenic gas mixtures by accounting for the operating conditions of cryogenic applications. Subsequently, we estimate the dielectric strength of the gas mixtures in terms of the density-reduced critical electric field ( ( E / N ) c r ), obtained by solving the Boltzmann equation with the two-term approximation method. Using the values of ( E / N ) c r , we calculate the critical electric field (Ecr) over the extended cryogenic operation range of 10-100 K at pressures between 1.0 and 2.0 MPa. The results show that the dielectric strength of cryogenic gas mixtures varies as a function of temperature at a constant operating pressure and reaches its minimum at the condensation point of each gas mixture. The results also suggest that ( E / N ) c r cannot accurately represent the maximum achievable dielectric strength of a gas mixture unless the maximum allowed mole fractions of gas species have been taken into account. Hence, we discuss ( E / N ) c r values that are derived from the regulated concentration of gas constituents, which will prevent the components of gas mixtures from condensing. This study provides useful recommendations on the suitability of the gas mixtures and useful reference data for the dielectric design of superconducting and cryogenic applications.

  17. Sharp transition between two regimes of operation of dc discharge with two anodes and thermionic emission from cathode

    SciTech Connect

    Mustafaev, A. S.; Grabovskiy, A.; Demidov, V. I.; Kaganovich, I. D.; Koepke, M. E.

    2014-05-15

    In a dc discharge plasma with two anodes and thermionic emission from cathode, the two anodes are used for plasma control. The main anode is placed between the cathode and the other auxiliary anode has a circular opening for passing electron current from the cathode to the second anode. It is experimentally demonstrated that a plasma may exhibit a sudden transition between two quasi-stable conditions as one increases the cathode-electron current collected by the auxiliary anode through an aperture, i.e., hole, in the main anode. In one regime, a bright glowing “ball-shaped double layer” appears on the plasma side having a potential drop of 10–15 eV and concomitant ionization in the neighboring region attached to the opening. The second regime is characterized by a uniform potential profile in plasma and an absence of the ball-shaped double layer. The transition between these regimes is accompanied by a significant change in plasma properties, such as the electron energy distribution function (EEDF). Controlling the EEDF is a valuable capability in technological applications. Increasing the gas pressure leads to the elimination of the first regime for sufficiently high gas pressure, the threshold being a few Torr. The disappearance of a regime transition can be explained by invoking an EEDF transition, from being nonlocal at low pressure to becoming local at high pressure. Local EEDF is determined by local values of electric field. Nonlocal EEDF is determined by electric field values elsewhere, and the electron can travel without energy loss over a path much longer than the discharge dimension.

  18. Sharp transition between two regimes of operation of dc discharge with two anodes and thermionic emission from cathode

    NASA Astrophysics Data System (ADS)

    Mustafaev, A. S.; Demidov, V. I.; Kaganovich, I. D.; Koepke, M. E.; Grabovskiy, A.

    2014-05-01

    In a dc discharge plasma with two anodes and thermionic emission from cathode, the two anodes are used for plasma control. The main anode is placed between the cathode and the other auxiliary anode has a circular opening for passing electron current from the cathode to the second anode. It is experimentally demonstrated that a plasma may exhibit a sudden transition between two quasi-stable conditions as one increases the cathode-electron current collected by the auxiliary anode through an aperture, i.e., hole, in the main anode. In one regime, a bright glowing "ball-shaped double layer" appears on the plasma side having a potential drop of 10-15 eV and concomitant ionization in the neighboring region attached to the opening. The second regime is characterized by a uniform potential profile in plasma and an absence of the ball-shaped double layer. The transition between these regimes is accompanied by a significant change in plasma properties, such as the electron energy distribution function (EEDF). Controlling the EEDF is a valuable capability in technological applications. Increasing the gas pressure leads to the elimination of the first regime for sufficiently high gas pressure, the threshold being a few Torr. The disappearance of a regime transition can be explained by invoking an EEDF transition, from being nonlocal at low pressure to becoming local at high pressure. Local EEDF is determined by local values of electric field. Nonlocal EEDF is determined by electric field values elsewhere, and the electron can travel without energy loss over a path much longer than the discharge dimension.

  19. UHF Signal Processing and Pattern Recognition of Partial Discharge in Gas-Insulated Switchgear Using Chromatic Methodology

    PubMed Central

    Wang, Xiaohua; Li, Xi; Rong, Mingzhe; Xie, Dingli; Ding, Dan; Wang, Zhixiang

    2017-01-01

    The ultra-high frequency (UHF) method is widely used in insulation condition assessment. However, UHF signal processing algorithms are complicated and the size of the result is large, which hinders extracting features and recognizing partial discharge (PD) patterns. This article investigated the chromatic methodology that is novel in PD detection. The principle of chromatic methodologies in color science are introduced. The chromatic processing represents UHF signals sparsely. The UHF signals obtained from PD experiments were processed using chromatic methodology and characterized by three parameters in chromatic space (H, L, and S representing dominant wavelength, signal strength, and saturation, respectively). The features of the UHF signals were studied hierarchically. The results showed that the chromatic parameters were consistent with conventional frequency domain parameters. The global chromatic parameters can be used to distinguish UHF signals acquired by different sensors, and they reveal the propagation properties of the UHF signal in the L-shaped gas-insulated switchgear (GIS). Finally, typical PD defect patterns had been recognized by using novel chromatic parameters in an actual GIS tank and good performance of recognition was achieved. PMID:28106806

  20. Steady-state canopy gas exchange: system design and operation

    NASA Technical Reports Server (NTRS)

    Bugbee, B.

    1992-01-01

    This paper describes the use of a commercial growth chamber for canopy photosynthesis, respiration, and transpiration measurements. The system was designed to measure transpiration via water vapor fluxes, and the importance of this measurement is discussed. Procedures for continuous measurement of root-zone respiration are described, and new data is presented to dispel myths about sources of water vapor interference in photosynthesis and in the measurement of CO2 by infrared gas analysis. Mitchell (1992) has described the fundamentals of various approaches to measuring photosynthesis. Because our system evolved from experience with other types of single-leaf and canopy gas-exchange systems, it is useful to review advantages and disadvantages of different systems as they apply to various research objectives.

  1. A Guidance Document for Kentucky's Oil and Gas Operators

    SciTech Connect

    Bender, Rick

    2002-03-18

    The accompanying report, manual and assimilated data represent the initial preparation for submission of an Application for Primacy under the Class II Underground Injection Control (UIC) program on behalf of the Commonwealth of Kentucky. The purpose of this study was to identify deficiencies in Kentucky law and regulation that would prevent the Kentucky Division of Oil and Gas from receiving approval of primacy of the UIC program, currently under control of the United States Environmental Protection Agency (EPA) in Atlanta, Georgia.

  2. Safe Management of Waste Generated during Shale Gas Operations

    NASA Astrophysics Data System (ADS)

    Kukulska-Zając, Ewa; Król, Anna; Holewa-Rataj, Jadwiga

    2017-04-01

    Exploration and exploitation of hydrocarbon deposits, regardless of their type, are connected with the generation of waste, which may have various environmental effects. Such wastes may pose a serious risk to the surrounding environment and public health because they usually contain numerous potentially toxic chemicals. Waste associated with exploration and exploitation of unconventional hydrocarbon deposits is composed of a mixture of organic and inorganic materials, the qualitative and quantitative composition of which changes widely over time, depending on numerous factors. As a result the proper characteristic of this type of waste is very important. Information gained from detailed chemical analyses of drilling chemicals, drilling wastes, and flowback water can be used to manage shale gas-related wastes more appropriately, to develop treatment methods, to store the waste, and assess the potential environmental and health risk. The following paper will focus mainly on the results of research carried out on waste samples coming from the unconventional hydrogen exploration sites. Additionally, regulatory frameworks applicable to the management of wastes produced during this type of works will be discussed. The scope of research concerning physicochemical parameters for this type of wastes will also be presented. The presented results were obtained during M4ShaleGas project realization. The M4ShaleGas project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement no. 640715.

  3. Investigation on the Minimum Maintenance Discharged Power of a Low-Frequency Driven Electrodeless Compact Fluorescent Lamp-Buffer Gas and Driving Frequency Dependence-

    NASA Astrophysics Data System (ADS)

    Arakawa, Takeshi; Seki, Katsushi; Katase, Koichi; Hashimotodani, Kiyoshi; Hochi, Akira

    We have investigated the minimum discharged power to maintain lamp plasma in terms of dependence on buffer gas condition and driving frequency of the electrodeless compact fluorescent lamp (ECFL). It is essential for realization of the low-frequency driven ECFL with inductively coupled plasma technique for household use. Considering the point of cost, the driving frequency of the electrodeless discharge lamp should be lowered because high frequency driving (> 1MHz) requires special components for reduction of EMI noise and circuit power loss with the increase in driving frequency. But it is difficult to maintain plasma at low frequency driving, since induced electric fields, which excited with the induction coil is declined and not receive energy for ionization and discharge sufficiently. Here, we indicated that the condition of minimum power to maintain the H-mode (inductively coupled) discharge described as simple functions of buffer gas pressure and driving frequency for a fixed lamp bulb shape and found that the relation can represent the measured data well. Using that relation, we can easily predict optimum buffer gas pressure from driving frequency and required minimum maintenance power on the commercially available (practical) standpoint.

  4. Gas-dynamic perturbations in an electric-discharge repetitively pulsed DF laser and the role of He in their suppression

    SciTech Connect

    Evdokimov, P A; Sokolov, D V

    2015-11-30

    The gas-dynamic perturbations in a repetitively pulsed DF laser are studied using a Michelson interferometer. Based on the analysis of experimental data obtained in two experimental sets (working medium without buffer gas and with up to 90% of He), it is concluded that such phenomena as isentropic expansion of a thermal plug, gas heating by shock waves and resonance acoustic waves do not considerably decrease the upper limit of the pulse repetition rate below a value determined by the time of the thermal plug flush out of the discharge gap. It is suggested that this decrease for a DF laser with the SF{sub 6} – D{sub 2} working mixture is caused by the development of overheat instability due to an increased energy deposition into the near-electrode regions and to the formation of electrode shock waves. Addition of He to the active media of the DF laser changes the discharge structure and improves its homogeneity over the discharge gape cross section, thus eliminating the reason for the development of this instability. A signification dilution of the active medium of a DF laser with helium up to the atmospheric pressure allowed us to achieve the limiting discharge initiation frequencies with the active medium replacement ratio K ∼ 1. (active media)

  5. Drilling and operating oil, gas, and geothermal wells in an H/sub 2/S environment

    SciTech Connect

    Dosch, M.W.; Hodgson, S.F.

    1981-01-01

    The following subjects are covered: facts about hydrogen sulfides; drilling and operating oil, gas, and geothermal wells; detection devices and protective equipment; hazard levels and safety procedures; first aid; and H/sub 2/S in California oil, gas, and geothermal fields. (MHR)

  6. Detection and quantification of fugitive emissions from Colorado oil and gas production operations using remote monitoring

    EPA Science Inventory

    Western states contain vast amounts of oil and gas production. For example, Weld County Colorado contains approximately 25,000 active oil and gas well sites with associated production operations. There is little information on the air pollutant emission potential from this source...

  7. 49 CFR 192.1005 - What must a gas distribution operator (other than a master meter or small LPG operator) do to...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false What must a gas distribution operator (other than a master meter or small LPG operator) do to implement this subpart? 192.1005 Section 192.1005...) § 192.1005 What must a gas distribution operator (other than a master meter or small LPG operator) do to...

  8. 49 CFR 192.1005 - What must a gas distribution operator (other than a master meter or small LPG operator) do to...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false What must a gas distribution operator (other than a master meter or small LPG operator) do to implement this subpart? 192.1005 Section 192.1005...) § 192.1005 What must a gas distribution operator (other than a master meter or small LPG operator) do to...

  9. 49 CFR 192.1005 - What must a gas distribution operator (other than a master meter or small LPG operator) do to...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false What must a gas distribution operator (other than a master meter or small LPG operator) do to implement this subpart? 192.1005 Section 192.1005...) § 192.1005 What must a gas distribution operator (other than a master meter or small LPG operator) do to...

  10. 49 CFR 192.1005 - What must a gas distribution operator (other than a master meter or small LPG operator) do to...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false What must a gas distribution operator (other than a master meter or small LPG operator) do to implement this subpart? 192.1005 Section 192.1005...) § 192.1005 What must a gas distribution operator (other than a master meter or small LPG operator) do to...

  11. 49 CFR 192.1005 - What must a gas distribution operator (other than a master meter or small LPG operator) do to...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false What must a gas distribution operator (other than a master meter or small LPG operator) do to implement this subpart? 192.1005 Section 192.1005...) § 192.1005 What must a gas distribution operator (other than a master meter or small LPG operator) do to...

  12. 77 FR 42679 - National Pollutant Discharge Elimination System (NPDES) Concentrated Animal Feeding Operation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-20

    ... and restore water quality by collecting certain information about concentrated animal feeding operations (CAFOs). The EPA also solicited comments on improving water quality by promoting environmental... from CAFOs to support the EPA in meeting its water quality protection responsibilities under the CWA...

  13. 76 FR 78599 - National Pollutant Discharge Elimination System (NPDES) Concentrated Animal Feeding Operation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-19

    ... 3334, 1301 Constitution Ave. NW., Washington, DC 20460. The Public Reading Room is open from 8:30 a.m... Reading Room is (202) 566-1744, and the telephone number for the Water Docket is (202) 566-2426. FOR...''). An animal feeding operation (AFO) is a CAFO if it meets the regulatory definition of a Large or...

  14. 76 FR 50240 - BOEMRE Information Collection Activity: 1010-0141, Oil and Gas Drilling Operations, Extension of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-12

    ...: 1010-0141, Oil and Gas Drilling Operations, Extension of a Collection; Submitted for Office of... the regulations under ``Oil and Gas Drilling Operations,'' and related documents. This notice also... CFR subpart 250, subpart D, Oil and Gas Drilling Operations. Forms: BOEMRE Forms 0123, 0123S, 0124...

  15. 76 FR 21395 - BOEMRE Information Collection Activity; 1010-0141, Subpart D, Oil and Gas Drilling Operations...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-15

    ...; 1010-0141, Subpart D, Oil and Gas Drilling Operations, Extension of a Collection; Comment Request... request (ICR) concerns the paperwork requirements related to oil and gas drilling operations, and related.... SUPPLEMENTARY INFORMATION: Title: 30 CFR Part 250, Subpart D, Oil and Gas Drilling Operations. BOEMRE Form(s...

  16. Assessment of the readiness of noble gas equipment for field operation in the IMS network

    NASA Astrophysics Data System (ADS)

    Wernsperger, Bernd; Auer, Matthias; Gohla, Herbert; Khrustalev, Kirill

    2010-05-01

    The radionuclide component of the International Monitoring System (IMS) consists of 80 radionuclide stations, of which 40 are equipped with noble-gas monitoring capability. Prior to the set-up of the IMS network, noble gas monitoring was only performed by a few institutions using manual, laboratory based systems. The deployment of noble gas systems in a world-wide network of monitoring stations required development of a new generation of equipment, which is reliable, suited for automated field operation at a detection sensitivity lower than previously achieved in laboratory based systems. New types of equipment have been developed and undergone extensive testing during the last 10 years under the framework of the ongoing International Noble Gas Experiment (INGE). During Phase III of INGE, three different types of noble gas systems are deployed into the IMS for testing. With altogether 17 systems in the field between 2004 to 2008 experience of more than 37 operational years has been accumulated. Operational parameters of the noble gas systems have improved during the entire Phase III from the first systems towards the latest state-of the art system generations. To ensure minimum down time any operational problems are addressed within the support system inside the PTS. Within this support system the operational performance is continuously monitored and particular problems are identified. The solution of operational problems is the joint objective of the PTS, the station operators and the system suppliers. Equipment reliability, operational procedures, maintenance and sparing plans are continuously reviewed and improved. The operational status of the IMS noble gas network during the Phase III exercise as well as the support strategy is presented.

  17. Petroleum industry in Illinois, 1975. Part I. Oil and gas developments. Part II. Waterflood operations

    SciTech Connect

    Van Den Berg, J.; Lawry, T.F.

    1976-01-01

    Tabulated data are presented for the state of Illinois for 1975 on various aspects of the petroleum and natural gas industries. Information about crude oil production, exploration and development drilling, crude oil reserves, productive acreage, gas production, and underground storage of natural gas and liquefied petroleum gas is included. Production of crude oil in 1975 was 5.4% less than in 1974. Statistics are presented for the various counties in the state. Information is also included on secondary recovery operations, including 27 new waterfloods.

  18. Operational Experience with the Internal Thermal Control System Dual-Membrane Gas Trap

    NASA Technical Reports Server (NTRS)

    Leimkuehler, Thomas O.; Lukens, Clark; Reeves, Daniel R.; Holt, James M.

    2003-01-01

    A dual-membrane gas trap is currently used to remove non-condensed gases (NCG) from the Internal Thermal Control System (ITCS) coolant on board the International Space Station. The gas trap consists of concentric tube membrane pairs, comprised of outer hydrophilic tubes and inner hydrophobic fibers. Liquid coolant passes through the outer hydrophilic membrane, which traps the NCG. The inner hydrophobic fiber allows the trapped NCG to pass through and vent to the ambient atmosphere in the cabin. The purpose of the gas trap is to prevent gas bubbles from causing depriming, overspeed, and shutdown of the ITCS pump, and the current gas trap has performed flawlessly in this regard. However, because of actual operational conditions on-orbit, its gas removal performance and operational lifetime have been affected. This paper discusses experiences with several of these dual- membrane gas traps, including on-orbit gas venting rate, effects due to the presence of nickel in the ITCS coolant, and subsequent refurbishing to remove the nickel from the gas trap.

  19. Gas chromatography coupled to tunable pulsed glow discharge time-of-flight mass spectrometry for environmental analysis.

    PubMed

    Solà-Vázquez, Auristela; Lara-Gonzalo, Azucena; Costa-Fernández, José M; Pereiro, Rosario; Sanz-Medel, Alfredo

    2010-05-01

    A tuneable microsecond pulsed direct current glow discharge (GD)-time-of-flight mass spectrometer MS(TOF) developed in our laboratory was coupled to a gas chromatograph (GC) to obtain sequential collection of the mass spectra, at different temporal regimes occurring in the GD pulses, during elution of the analytes. The capabilities of this set-up were explored using a mixture of volatile organic compounds of environmental concern: BrClCH, Cl(3)CH, Cl(4)C, BrCl(2)CH, Br(2)ClCH, Br(3)CH. The experimental parameters of the GC-pulsed GD-MS(TOF) prototype were optimized in order to separate appropriately and analyze the six selected organic compounds, and two GC carrier gases, helium and nitrogen, were evaluated. Mass spectra for all analytes were obtained in the prepeak, plateau and afterpeak temporal regimes of the pulsed GD. Results showed that helium offered the best elemental sensitivity, while nitrogen provided higher signal intensities for fragments and molecular peaks. The analytical performance characteristics were also worked out for each analyte. Absolute detection limits obtained were in the order of ng. In a second step, headspace solid phase microextraction (HS SPME), as sample preparation and preconcentration technique, was evaluated for the quantification of the compounds under study, in order to achieve the required analytical sensitivity for trihalomethanes European Union (EU) environmental legislation. The analytical figures of merit obtained using the proposed methodology showed rather good detection limits (between 2 and 13 microg L(-1) depending on the analyte). In fact, the developed methodology met the EU legislation requirements (the maximum level permitted in tap water for the "total trihalomethanes" is set at 100 microg L(-1)). Real analysis of drinking water and river water were successfully carried out. To our knowledge this is the first application of GC-pulsed GD-MS(TOF) for the analysis of real samples. Its ability to provide elemental

  20. Application of electrophoton capture (EPC) analysis based on gas discharge visualization (GDV) technique in medicine: a systematic review.

    PubMed

    Korotkov, Konstantin G; Matravers, Peter; Orlov, Dmitry V; Williams, Bernard O

    2010-01-01

    The objective of this study was to evaluate the scale and scope of implementing electrophoton capture (EPC) analysis based on gas discharge visualization (GDV) technique in diverse medical applications and psychophysiology; to identify the range of applications in medicine; and to show in which areas the procedure can be useful to health professionals. The design of the study is a systematic review. The database included articles published in peer-reviewed journals, proceedings of the international scientific congress "Science, Information, Spirit" (2003-2007), articles from the International Union of Medical and Applied Bioelectrography database, and proceedings of other conferences devoted to EPC or GDV, bioelectrography, and biophotonics. Search restrictions were human subjects, English or Russian language, and publication date from 2003 to 2007. All randomized controlled studies (RCTs) and systematic research reports (SRRs) were evaluated using Scottish Intercollegiate Guidelines Network and Jadad checklists. The search yielded 136 articles addressing four different fields of medical and psychophysiologic applications of EPC (GDV). Among them were 26 SRR, 19 RCT, 18 case reports or case series, and 13 cohort studies. Thirteen (13) RCTs and 19 SRRs were rated "high" on the two conventional checklists. (1) The software and equipment EPC/GDV-complex is a convenient and easy-to-use device, easily allows examining patients with various pathologies and, therefore, offers a wide range of applications. (2) The GDV method has shown itself to be very fast (i.e., it is an "express-method" for studying states of the human organism). (3) Our review has revealed that GDV method can be implemented as an express method for assessment of treatment procedure effectiveness, evaluating emotional and physical conditions of people, and in many other fields.

  1. 76 FR 49463 - Pacific Gas and Electric Company; Notice of Authorization for Continued Project Operation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-10

    ... Project Operation On June 16, 2009, Pacific Gas and Electric Company, licensee for the McCloud-Pit... Commission's regulations thereunder. The McCloud-Pit Hydroelectric Project is located on the McCloud and Pit... authorized to continue operation of the McCloud-Pit Hydroelectric Project, until such time as the Commission...

  2. 78 FR 29365 - Pacific Gas and Electric Company; Notice of Authorization for Continued Project Operation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-20

    ... Project Operation On April 12, 2011, the Pacific Gas and Electric Company, licensee for the Drum-Spaulding... Commission's regulations thereunder. The Drum-Spaulding Hydroelectric Project is located on South Yuba River... authorized to continue operation of the Drum-Spaulding Hydroelectric Project, until such time as the...

  3. Transfer of charges and substances in a gas-discharge plasma from the liquid electrolyte cathode containing salts of alkali metal

    NASA Astrophysics Data System (ADS)

    Tazmeev, Kh K.; Timerkaev, B. A.; Tazmeev, G. K.

    2017-11-01

    A gas discharge in the air between the flowing liquid cathode and a solid anode was studied experimentally. Aqueous solution of sodium chloride was used as the liquid cathode electrolyte. Mass loss due to evaporating and sputtering was compensated by adding distilled water in a continuous mode. It was found that the specific electric conductivity of the aqueous solution is almost unchanged. The regularities of changes in the composition of an anionic solution were discovered.

  4. Mid-section of a can-annular gas turbine engine with a radial air flow discharged from the compressor section

    DOEpatents

    Little, David A.; McQuiggan, Gerard; Wasdell, David L.

    2016-10-25

    A midframe portion (213) of a gas turbine engine (210) is presented, and includes a compressor section (212) configured to discharge an air flow (211) directed in a radial direction from an outlet of the compressor section (212). Additionally, the midframe portion (213) includes a manifold (214) to directly couple the air flow (211) from the compressor section (212) outlet to an inlet of a respective combustor head (218) of the midframe portion (213).

  5. Barium Depletion in the NSTAR Discharge Cathode After 30,000 Hours of Operation

    NASA Technical Reports Server (NTRS)

    Polk, James E.; Capece, Angela M.; Mikellides, Ioannis G.; Katz, Ira

    2010-01-01

    Dispenser hollow cathodes rely on a consumable supply of barium released by impregnant materials in the pores of a tungsten matrix to maintain a low work function surface. Examinations of cathode inserts from long duration ion engine tests show deposits of tungsten at the downstream end that appear to block the flow of barium from the interior. In addition, a numerical model of barium transport in the insert plasma indicates that the barium partial pressure in the insert may exceed the equilibrium vapor pressure of the dominant barium-producing reaction, and it was postulated previously that this would suppress barium loss in the upstream part of the insert. New measurements of the depth of barium depletion from a cathode insert operated for 30,352 hours reveal that barium loss is confined to a narrow region near the downstream end, confirming this hypothesis.

  6. MHSP in reversed-bias operation mode for ion blocking in gas-avalanche multipliers

    NASA Astrophysics Data System (ADS)

    Veloso, J. F. C. A.; Amaro, F. D.; Maia, J. M.; Lyashenko, A. V.; Breskin, A.; Chechik, R.; dos Santos, J. M. F.; Bouianov, O.; Bouianov, M.

    2005-08-01

    We present recent results on the operation of gas-avalanche detectors comprising a cascade of gas electron multipliers (GEMs) and Mico-Hole & Strip Plate (MHSP) multiplier operated in reversed-bias (R-MHSP) mode. The operation mechanism of the R-MHSP is explained and its potential contribution to ion-backflow (IBF) reduction is demonstrated. IBF values of 4×10 -3 were obtained in cascaded R-MHSP and GEM multipliers at gains of about 10 4, though at the expense of reduced effective gain in the first R-MHSP multiplier in the cascade.

  7. Landfill gas operation and maintenance manual of practice

    SciTech Connect

    1997-03-01

    This manual has the following objectives: (1) compile and present key portions of the general body of knowledge about operating and maintaining LFG control systems; (2) present information in an easy to understand format useful for hands-on practical use in the field; (3) present accepted practices and procedures for LFG control practices; (4) highlight key points, common mistakes and lessons learned from more than 20 years of industry experience, point out areas of controversy and indicate alternative practices where applicable; (5) compile key reference information; and (6) provide theory and discussion needed to develop a deeper understanding of LFG control and recovery.

  8. The influence of carrier gas on plasma properties and hydrogen peroxide production in a nanosecond pulsed plasma discharge generated in a water-film plasma reactor

    NASA Astrophysics Data System (ADS)

    Wang, Huihui; Wandell, Robert J.; Locke, Bruce R.

    2018-03-01

    The influence of carrier gas (argon and helium) on the properties of a nanosecond pulsed filamentary discharge propagating along the water surface in a water film plasma reactor, and the effects of plasma properties on the formation of hydrogen peroxide (H2O2) are investigated. The plasma properties, including electron density, gas temperature, and plasma volume, and the hydrogen peroxide production rate and energy yield were measured and compared in both argon and helium discharges. The results show that helium plasma is more diffusive compared with the argon plasma, and it has lower electron density and gas temperature but larger volume. The production rates and energy yields of hydrogen peroxide are only slightly higher in the helium plasma although the electron density is much lower. A simple mathematical model with time-dependent fast radical and electron quenching in a small film surrounding the plasma core and with lumped reaction kinetics for H2O2 formation and degradation suggests that the hydroxyl radical (·OH) concentration is approximately two times higher in the argon discharge, but the larger volume of the helium leads to about two times more total ·OH in the helium with correspondingly higher energy yields. The experimental data and model imply that the H2O2 energy yield may increase at lower power (or specific energy density) for both carrier gases.

  9. Pulsed laser facilities operating from UV to IR at the Gas Laser Lab of the Lebedev Institute

    NASA Astrophysics Data System (ADS)

    Ionin, Andrei; Kholin, Igor; Vasil'Ev, Boris; Zvorykin, Vladimir

    2003-05-01

    Pulsed laser facilities developed at the Gas Lasers Lab of the Lebedev Physics Institute and their applications for different laser-matter interactions are discussed. The lasers operating from UV to mid-IR spectral region are as follows: e-beam pumped KrF laser (λ= 0.248 μm) with output energy 100 J; e-beam sustained discharge CO2(10.6 μm) and fundamental band CO (5-6 μm) lasers with output energy up to ~1 kJ; overtone CO laser (2.5-4.2 μm) with output energy ~ 50 J and N2O laser (10.9 μm) with output energy of 100 J; optically pumped NH3 laser (11-14 μm). Special attention is paid to an e-beam sustained discharge Ar-Xe laser (1.73 μm ~ 100 J) as a potential candidate for a laser-propulsion facility. The high energy laser facilities are used for interaction of laser radiation with polymer materials, metals, graphite, rocks, etc.

  10. In-ground operation of Geothermic Fuel Cells for unconventional oil and gas recovery

    NASA Astrophysics Data System (ADS)

    Sullivan, Neal; Anyenya, Gladys; Haun, Buddy; Daubenspeck, Mark; Bonadies, Joseph; Kerr, Rick; Fischer, Bernhard; Wright, Adam; Jones, Gerald; Li, Robert; Wall, Mark; Forbes, Alan; Savage, Marshall

    2016-01-01

    This paper presents operating and performance characteristics of a nine-stack solid-oxide fuel cell combined-heat-and-power system. Integrated with a natural-gas fuel processor, air compressor, reactant-gas preheater, and diagnostics and control equipment, the system is designed for use in unconventional oil-and-gas processing. Termed a ;Geothermic Fuel Cell; (GFC), the heat liberated by the fuel cell during electricity generation is harnessed to process oil shale into high-quality crude oil and natural gas. The 1.5-kWe SOFC stacks are packaged within three-stack GFC modules. Three GFC modules are mechanically and electrically coupled to a reactant-gas preheater and installed within the earth. During operation, significant heat is conducted from the Geothermic Fuel Cell to the surrounding geology. The complete system was continuously operated on hydrogen and natural-gas fuels for ∼600 h. A quasi-steady operating point was established to favor heat generation (29.1 kWth) over electricity production (4.4 kWe). Thermodynamic analysis reveals a combined-heat-and-power efficiency of 55% at this condition. Heat flux to the geology averaged 3.2 kW m-1 across the 9-m length of the Geothermic Fuel Cell-preheater assembly. System performance is reviewed; some suggestions for improvement are proposed.

  11. Incinerator operating conditions affect combustion gas levels of dioxins, furans

    SciTech Connect

    Not Available

    1987-10-01

    New research shows levels of dioxins and furans can be minimized by good combustion practices at a garbage-burning incinerator, according to results of the Combustion and Emissions Research Project at the VICON Incinerator Facility. The project focused on how a wide range of combustion conditions and different types of refuse quality affected the amount of dioxins and furans formed and destroyed during the combustion process. The results of the research show concentrations of dioxins and furans among the lowest measured at any incinerator. Tests were conducted over a broad range of operating conditions, with furnace temperatures as low as 1300 degrees and as high as 1900 degrees Fahrenheit. The only increase in dioxins and furans during testing occurred when incinerator temperatures were reduced below 1500 degrees Fahrenheit.

  12. Excimer Lasers With Capacitively Excited Tubular Discharges

    NASA Astrophysics Data System (ADS)

    Eichler, Hans J.; Herweg, Helmut; de la Rosa, Jose

    1989-04-01

    The excitation of excimer lasers in tubular discharges results in simple and compact devices needing no preionization. Optical output energies are in the millijoule range. We investigated XeF, KrF and ArF lasers for various operating conditions. The lasers consist of capillary glass tubes with two internal electrodes at the ends and an aluminium-foil wrapped around the tube as capacitive electrode. A maximum output energy of 0.3 mJ has been achieved for the XeF laser. The good quality of the discharge is indicated by the observation of spontaneous mode locking. The detailed study of the discharge for different polarities of the electrodes has shown that efficient operation with a high gas lifetime can be obtained by a purely capacitively excited discharge. A gas lifetime of about 10,000 pulses for 3 litres gas mixture has been observed. Using a two stage Marx generator to generate 100 kV excitation voltage a maximum output energy of 0.7 mJ was obtained for a gas mixture of Kr, F2 and He with an efficiency of 0.17%. The KrF laser operates also without the buffer gas. Laser action in ArF has been achieved with 15 μJ pulse energy and 10 ns duration.

  13. Methodology for optimizing the development and operation of gas storage fields

    SciTech Connect

    Mercer, J.C.; Ammer, J.R.; Mroz, T.H.

    1995-04-01

    The Morgantown Energy Technology Center is pursuing the development of a methodology that uses geologic modeling and reservoir simulation for optimizing the development and operation of gas storage fields. Several Cooperative Research and Development Agreements (CRADAs) will serve as the vehicle to implement this product. CRADAs have been signed with National Fuel Gas and Equitrans, Inc. A geologic model is currently being developed for the Equitrans CRADA. Results from the CRADA with National Fuel Gas are discussed here. The first phase of the CRADA, based on original well data, was completed last year and reported at the 1993 Natural Gas RD&D Contractors Review Meeting. Phase 2 analysis was completed based on additional core and geophysical well log data obtained during a deepening/relogging program conducted by the storage operator. Good matches, within 10 percent, of wellhead pressure were obtained using a numerical simulator to history match 2 1/2 injection withdrawal cycles.

  14. Comparative Study on Extinction Process of Gas-Blasted Air and CO2 Arc Discharge Using Two-Dimensional Electron Density Imaging Sensor

    NASA Astrophysics Data System (ADS)

    Inada, Yuki; Kamiya, Tomoki; Matsuoka, Shigeyasu; Kumada, Akiko; Ikeda, Hisatoshi; Hidaka, Kunihiko; Nakano, Tomoyuki; Murai, Kosuke; Tanaka, Yasunori; Shinkai, Takeshi

    2015-09-01

    Systematic comparison of the electron density images for various kinds of arc-quenching gas media inside high-voltage circuit breakers is a promising method for the effective search and development of SF6-alternative gases. However, electron density imaging over the decaying arcs around the nozzle throat of the circuit breakers is extremely difficult by using the conventional arc generation setup and localized type sensing systems, due to the nozzle opaqueness and spatiotemporal instability of long-gap arc discharges around current zero. Here, we achieved two-dimensional electron density imaging over the decaying arcs around the nozzle throat first in the world, by a combination of the development of a unique gas flow nozzle integrating a cubic quartz cell and the single-shot recordings using Shack-Hartmann sensors. Shack-Hartmann sensors were applied to gas-blasted air and CO2 arc discharges under current-zero phases after sudden switch-off of stationary arc currents. These experimental results showed that the electron densities and arc diameters took the minimums in the upper stream nozzle regions with the maximum blasting gas speeds. In addition, CO2 had a shorter electron density decaying time constant than air, which is consistent with the previous theoretical studies on higher interruption performance of CO2 compared with air.

  15. Net sputtering rate due to hot ions in a Ne-Xe discharge gas bombarding an MgO layer

    SciTech Connect

    Ho, S.; Tamakoshi, T.; Ikeda, M.; Mikami, Y.; Suzuki, K.

    2011-04-15

    An analytical method is developed for determining net sputtering rate for an MgO layer under hot ions with low energy (<100 eV) in a neon-xenon discharge gas at near-atmospheric pressure. The primary sputtering rate is analyzed according to spatial and energy distributions of the hot ions with average energy, E{sup h}{sub i}, above a threshold energy of sputtering, E{sub th,i}, multiplied by a yield coefficient. The threshold energy of sputtering is determined from dissociation energy required to remove an atom from MgO surface multiplied by an energy-transfer coefficient. The re-deposition rate of the sputtered atoms is calculated by a diffusion simulation using a hybridized probabilistic and analytical method. These calculation methods are combined to analyze the net sputtering rate. Maximum net sputtering rate due to the hot neon ions increases above the partial pressure of 4% xenon as E{sup h}{sub Ne} becomes higher and decreases near the partial pressure of 20% xenon as ion flux of neon decreases. The dependence due to the hot neon ions on partial pressure and applied voltage agrees well with experimental results, but the dependence due to the hot xenon ions deviates considerably. This result shows that the net sputtering rate is dominated by the hot neon ions. Maximum E{sup h}{sub Ne} (E{sup h}{sub Ne,max} = 5.3 - 10.3 eV) is lower than E{sub th,Ne} (19.5 eV) for the MgO layer; therefore, weak sputtering due to the hot neon ions takes place. One hot neon ion sputters each magnesium and each oxygen atom on the surface and distorts around a vacancy. The ratio of the maximum net sputtering rate is approximately determined by number of the ions at E{sup h}{sub i,max} multiplied by an exponential factor of -E{sub th,i}/E{sup h}{sub i,max}.

  16. Flared natural gas-based onsite atmospheric water harvesting (AWH) for oilfield operations

    NASA Astrophysics Data System (ADS)

    Wikramanayake, Enakshi D.; Bahadur, Vaibhav

    2016-03-01

    Natural gas worth tens of billions of dollars is flared annually, which leads to resource waste and environmental issues. This work introduces and analyzes a novel concept for flared gas utilization, wherein the gas that would have been flared is instead used to condense atmospheric moisture. Natural gas, which is currently being flared, can alternatively power refrigeration systems to generate the cooling capacity for large scale atmospheric water harvesting (AWH). This approach solves two pressing issues faced by the oil-gas industry, namely gas flaring, and sourcing water for oilfield operations like hydraulic fracturing, drilling and water flooding. Multiple technical pathways to harvest atmospheric moisture by using the energy of natural gas are analyzed. A modeling framework is developed to quantify the dependence of water harvest rates on flared gas volumes and ambient weather. Flaring patterns in the Eagle Ford Shale in Texas and the Bakken Shale in North Dakota are analyzed to quantify the benefits of AWH. Overall, the gas currently flared annually in Texas and North Dakota can harvest enough water to meet 11% and 65% of the water consumption in the Eagle Ford and the Bakken, respectively. Daily harvests of upto 30 000 and 18 000 gallons water can be achieved using the gas currently flared per well in Texas and North Dakota, respectively. In fifty Bakken sites, the water required for fracturing or drilling a new well can be met via onsite flared gas-based AWH in only 3 weeks, and 3 days, respectively. The benefits of this concept are quantified for the Eagle Ford and Bakken Shales. Assessments of the global potential of this concept are presented using data from countries with high flaring activity. It is seen that this waste-to-value conversion concept offers significant economic benefits while addressing critical environmental issues pertaining to oil-gas production.

  17. Performance and Operational Characteristics for a Dual Brayton Space Power System With Common Gas Inventory

    NASA Technical Reports Server (NTRS)

    Johnson, Paul K.; Mason, Lee S.

    2006-01-01

    This paper provides an analytical evaluation on the operation and performance of a dual Brayton common gas system. The NASA Glenn Research Center in-house computer program Closed Cycle System Simulation (CCSS) was used to construct a model of two identical 50 kWe-class recuperated closed-Brayton-cycle (CBC) power conversion units that share a common gas inventory and single heat source. As operating conditions for each CBC change, the total gas inventory is redistributed between the two units and overall system performance is affected. Several steady-state off-design operating points were analyzed by varying turbine inlet temperature and turbo-alternator shaft rotational speed to investigate the interaction of the two units.

  18. Continuous-flow gas-lift installation design utilizing production-pressure-operated valve performance

    SciTech Connect

    Winkler, H.W.

    1995-12-31

    The variable-gradient design-line method is a widely accepted procedure for spacing gas-lift valves (GLVs) in a continuous-flow gas-lift (GL) installation. Injection-pressure-operated (IPO) and production-pressure-operated (PPO) GLVs can be used in a variable gradient designed installation. The primary purpose of GLVs is to unload a well to the desired depth of gas injection. If the installation design is based on a constant surface injection-gas pressure (p{sub io}), the GLVs must be opened by an increase in the flowing-production pressure at valve depth (p{sub pfD}) rather than an increase in injection-gas pressure at valve depth (p{sub ioD}). PPO, also called fluid-operated, valvesmore » are opened and closed by changes in p{sub pfD}. This paper outlines in detail the calculations for a variable-gradient continuous-flow installation design procedure based on a constant p{sub io} for spacing the unloading PPO valves. The valve spacing and port size selection includes performance characteristics of PPO GLVs. A simplified method for calculating the injection daily volumetric gas rate (q{sub gsc}) throughput of an unbalanced bellows type of PPO valve on the basis of a change in p{sub pfD} and the valve bellows-assembly load rate (B{sub lr}) is given in the Appendix.« less

  19. Costs and indices for domestic oil and gas field equipment and production operations 1990 through 1993

    SciTech Connect

    Not Available

    1994-07-08

    This report presents estimated costs and indice for domestic oil and gas field equipment and production operations for 1990, 1991, 1992, and 1993. The costs of all equipment and serives were those in effect during June of each year. The sums (aggregates) of the costs for representative leases by region, depth, and production rate were averaged and indexed. This provides a general measure of the increased or decreased costs from year to year for lease equipment and operations. These general measures do not capture changes in industry-wide costs exactly because of annual variations in the ratio of oil wells tomore » gas wells. The body of the report contains summary tables, and the appendices contain detailed tables. Price changes for oil and gas, changes in taxes on oil and gas revenues, and environmental factors (costs and lease availability) have significant impact on the number and cost of oil and gas wells drilled. These changes also impact the cost of oil and gas production equipment and operations.« less

  20. Field Practices Installation and operations of a landfill gas collection and flare system

    SciTech Connect

    Dellinger, A.S.; Greeb, K.W.

    1995-08-01

    The Sheldon-Arleta Landfill was operated by the City of Los Angeles from 1962 until 1974. Refuse was landfilled in what was formerly a quarry pit and placed prior to development and use of clay and synthetic liner materials. This paper is a continuance of the paper presented at the 17th Annual Landfill Gas Symposium-identifying sources and causes of landfill gas migration hazards, the design for their remediation, and the field construction/implementation of those designs to remediate landfill gas migration hazards.

  1. Comparative study on extinction process of gas-blasted air and CO2 arc discharge using two-dimensional electron density imaging sensor

    NASA Astrophysics Data System (ADS)

    Inada, Yuki; Kumada, Akiko; Ikeda, Hisatoshi; Hidaka, Kunihiko; Nakano, Tomoyuki; Murai, Kosuke; Tanaka, Yasunori; Shinkai, Takeshi

    2017-05-01

    Shack-Hartmann type laser wavefront sensors were applied to gas-blasted arc discharges under current-zero phases, generated in a 50 mm-long interelectrode gap confined by a gas flow nozzle, in order to conduct a systematic comparison of electron density decaying processes for two kinds of arc-quenching gas media: air and \\text{C}{{\\text{O}}2} . The experimental results for the air and \\text{C}{{\\text{O}}2} arc plasmas showed that the electron densities and arc diameters became thinner toward the nozzle-throat inlet due to a stronger convection loss in the arc radial direction. In addition, \\text{C}{{\\text{O}}2} had a shorter electron density decaying time constant than air, which could be caused by convection loss and turbulent flow of \\text{C}{{\\text{O}}2} stronger than air.

  2. Simultaneous determination of dissolved gases and moisture in mineral insulating oils by static headspace gas chromatography with helium photoionization pulsed discharge detection.

    PubMed

    Jalbert, J; Gilbert, R; Tétreault, P

    2001-07-15

    This paper presents the development of a static headspace capillary gas chromatographic method (HS-GC) for simultaneously determining dissolved gases (H2, O2, N2, CO, CO2, CH4, C2H6, C2H4, C2H2, C3H8) and moisture from a unique 15-mL mineral oil sample. A headspace sampler device is used to equilibrate the sample species in a two-phase system under controlled temperature and agitation conditions. A portion of the equilibrated species is then automatically split-injected into two chromatographic channels mounted on the same GC for their separation. The hydrocarbons and the lighter gases are separated on the first channel by a GS-Q column coupled with a MolSieve 5-A column via a bypass valve, while the moisture is separated on the second channel using a Stabilwax column. The analytes are detected by using two universal pulsed-discharge helium ionization detectors (PDHID). The performance of the method was established using equilibrated vials containing known amounts of gas mixture, water, and blank oil. The signal is linear over the concentration ranges normally found for samples collected from open-breathing power transformers. Determination sensitivity varies with the nature of the species considered with values as high as 21 500 A x 10(-9) s (microg/ g)(-1) for H2O, 46-216 A x 10(-9) s (microL/L)(-1) for the hydrocarbons and carbon oxides, and as low as 8-21 A x 10(-9) s (microL/L)(-1) for the O2 and N2 permanent gases. The detection limit of the method is between 0.08 and 6 microL/L for the dissolved gases, except for O2, N2, and CO2, where higher values are observed due to air intrusion during sampler operations, and 0.1 microg/g for the dissolved water. Ten consecutive measurements in the low and high levels of the calibration curves have shown a precision better than 12% and 6%, respectively, in all cases. A comparison study between the HS-GC method and the ASTM standard procedures on 31 field samples showed a very good agreement of the results. The advantages

  3. Neutral gas temperature maps of the pin-to-plate argon micro discharge into the ambient air

    SciTech Connect

    Xu, S. F.; Zhong, X. X., E-mail: xxzhong@sjtu.edu.cn; Majeed, Asif

    2015-03-15

    This study is designed to explore the two dimensional temperature maps of the atmospheric argon discharge consisting of pin-to-plane electrodes supplied by a high voltage DC source. After checking the stability of the micro discharge, the two dimensional image plane focused by a quartz lens was scanned by the fiber probe driven by a 3D Mobile Platform. The rotational and vibrational temperatures are calculated using nitrogen emissions collected by the high resolution spectrometer and high sensitive intensified charge coupled device. The rotational temperature varies from 1558.15 K to 2621.14 K and vibrational temperature varies from 3010.38 K to 3774.69 K, indicating a great temperaturemore » gradient due to small discharge size. The temperature maps show a lateral expansion and a sharp truncation in the radial direction. A double layers discharge is identified, where an arc discharge coats the glow discharge.« less

  4. Operation, Modeling and Analysis of the Reverse Water Gas Shift Process

    NASA Technical Reports Server (NTRS)

    Whitlow, Jonathan E.

    2001-01-01

    The Reverse Water Gas Shift process is a candidate technology for water and oxygen production on Mars under the In-Situ Propellant Production project. This report focuses on the operation and analysis of the Reverse Water Gas Shift (RWGS) process, which has been constructed at Kennedy Space Center. A summary of results from the initial operation of the RWGS, process along with an analysis of these results is included in this report. In addition an evaluation of a material balance model developed from the work performed previously under the summer program is included along with recommendations for further experimental work.

  5. 40 CFR 60.103a - Design, equipment, work practice or operational standards.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... costs (capital and annual operating), natural gas offset credits (if applicable), technical feasibility... process gas discharge to the flare through process operating changes or gas recovery at the source. (ii) Reduction of the volume of process gas to the flare through process operating changes. (iii) Installation of...

  6. 40 CFR 60.103a - Design, equipment, work practice or operational standards.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... costs (capital and annual operating), natural gas offset credits (if applicable), technical feasibility... process gas discharge to the flare through process operating changes or gas recovery at the source. (ii) Reduction of the volume of process gas to the flare through process operating changes. (iii) Installation of...

  7. Modeling Studies to Constrain Fluid and Gas Migration Associated with Hydraulic Fracturing Operations

    NASA Astrophysics Data System (ADS)

    Rajaram, H.; Birdsell, D.; Lackey, G.; Karra, S.; Viswanathan, H. S.; Dempsey, D.

    2015-12-01

    The dramatic increase in the extraction of unconventional oil and gas resources using horizontal wells and hydraulic fracturing (fracking) technologies has raised concerns about potential environmental impacts. Large volumes of hydraulic fracturing fluids are injected during fracking. Incidents of stray gas occurrence in shallow aquifers overlying shale gas reservoirs have been reported; whether these are in any way related to fracking continues to be debated. Computational models serve as useful tools for evaluating potential environmental impacts. We present modeling studies of hydraulic fracturing fluid and gas migration during the various stages of well operation, production, and subsequent plugging. The fluid migration models account for overpressure in the gas reservoir, density contrast between injected fluids and brine, imbibition into partially saturated shale, and well operations. Our results highlight the importance of representing the different stages of well operation consistently. Most importantly, well suction and imbibition both play a significant role in limiting upward migration of injected fluids, even in the presence of permeable connecting pathways. In an overall assessment, our fluid migration simulations suggest very low risk to groundwater aquifers when the vertical separation from a shale gas reservoir is of the order of 1000' or more. Multi-phase models of gas migration were developed to couple flow and transport in compromised wellbores and subsurface formations. These models are useful for evaluating both short-term and long-term scenarios of stray methane release. We present simulation results to evaluate mechanisms controlling stray gas migration, and explore relationships between bradenhead pressures and the likelihood of methane release and transport.

  8. Kinetics and dynamics of nanosecond streamer discharge in atmospheric-pressure gas bubble suspended in distilled water under saturated vapor pressure conditions

    NASA Astrophysics Data System (ADS)

    Sharma, Ashish; Levko, Dmitry; Raja, Laxminarayan L.; Cha, Min Suk

    2016-10-01

    We perform computational studies of nanosecond streamer discharges generated in helium bubbles immersed in distilled water under atmospheric pressure conditions. The model takes into account the presence of water vapor in the gas bubble for an accurate description of the discharge kinetics. We find that the dynamic characteristics of the streamer discharge are different at low and high positive trigger voltages with the axial streamer evolution dominant for low voltages and a surface hugging mode favored for high voltages. We also find a substantial difference in initiation, transition and evolution stages of discharge for positive and negative trigger voltages with the volumetric distribution of species in the streamer channel much more uniform for negative trigger voltages on account of the presence of multiple streamers. We observe that the presence of water vapor does not affect the breakdown voltage even for oversaturated conditions but significantly influences the composition of dominant species in the trail of the streamer as well as the flux of the dominant species on the bubble surface.

  9. Study of the operating parameters of a helicon plasma discharge source using PIC-MCC simulation technique

    NASA Astrophysics Data System (ADS)

    Jaafarian, Rokhsare; Ganjovi, Alireza; Etaati, Gholamreza

    2018-01-01

    In this work, a Particle in Cell-Monte Carlo Collision simulation technique is used to study the operating parameters of a typical helicon plasma source. These parameters mainly include the gas pressure, externally applied static magnetic field, the length and radius of the helicon antenna, and the frequency and voltage amplitude of the applied RF power on the helicon antenna. It is shown that, while the strong radial gradient of the formed plasma density in the proximity of the plasma surface is substantially proportional to the energy absorption from the existing Trivelpiece-Gould (TG) modes, the observed high electron temperature in the helicon source at lower static magnetic fields is significant evidence for the energy absorption from the helicon modes. Furthermore, it is found that, at higher gas pressures, both the plasma electron density and temperature are reduced. Besides, it is shown that, at higher static magnetic fields, owing to the enhancement of the energy absorption by the plasma charged species, the plasma electron density is linearly increased. Moreover, it is seen that, at the higher spatial dimensions of the antenna, both the plasma electron density and temperature are reduced. Additionally, while, for the applied frequencies of 13.56 MHz and 27.12 MHz on the helicon antenna, the TG modes appear, for the applied frequency of 18.12 MHz on the helicon antenna, the existence of helicon modes is proved. Moreover, by increasing the applied voltage amplitude on the antenna, the generation of mono-energetic electrons is more probable.

  10. Final report on evaluation of cyclocraft support of oil and gas operations in wetland areas

    SciTech Connect

    Eggington, W.J.; Stevens, P.M.; John, C.J.

    1994-10-01

    The cyclocraft is a proven hybrid aircraft, capable of VTOL, lifting heavy and bulky loads, highly controllable, having high safety characteristics and low operating costs. Mission Research Corporation (MRC), under Department of Energy sponsorship, is evaluating the potential use of cyclocraft in the transport of drill rigs, mud, pipes and other materials and equipment, in a cost effective and environmentally safe manner, to support oil and gas drilling, production, and transportation operations in wetland areas. Based upon the results of an earlier parametric study, a cyclocraft design, having a payload capacity of 45 tons and designated H.1 Cyclocraft, was selectedmore » for further study, including the preparation of a preliminary design and a development plan, and the determination of operating costs. This report contains all of the results derived from the program to evaluate the use of cyclocraft in the support of oil and gas drilling and production operations in wetland areas.« less

  11. Final report on evaluation of cyclocraft support of oil and gas operations in wetland areas

    SciTech Connect

    Eggington, W.J.; Stevens, P.M.; John, C.J.; Harder, B.J.; Lindstedt, D.M.

    1994-10-01

    The cyclocraft is a proven hybrid aircraft, capable of VTOL, lifting heavy and bulky loads, highly controllable, having high safety characteristics and low operating costs. Mission Research Corporation (MRC), under Department of Energy sponsorship, is evaluating the potential use of cyclocraft in the transport of drill rigs, mud, pipes and other materials and equipment, in a cost effective and environmentally safe manner, to support oil and gas drilling, production, and transportation operations in wetland areas. Based upon the results of an earlier parametric study, a cyclocraft design, having a payload capacity of 45 tons and designated H.1 Cyclocraft, was selected for further study, including the preparation of a preliminary design and a development plan, and the determination of operating costs. This report contains all of the results derived from the program to evaluate the use of cyclocraft in the support of oil and gas drilling and production operations in wetland areas.

  12. A Thomson-type mass and energy spectrometer for characterizing ion energy distributions in a coaxial plasma gun operating in a gas-puff mode

    NASA Astrophysics Data System (ADS)

    Rieker, G. B.; Poehlmann, F. R.; Cappelli, M. A.

    2013-07-01

    Measurements of ion energy distribution are performed in the accelerated plasma of a coaxial electromagnetic plasma gun operating in a gas-puff mode at relatively low discharge energy (900 J) and discharge potential (4 kV). The measurements are made using a Thomson-type mass and energy spectrometer with a gated microchannel plate and phosphor screen as the ion sensor. The parabolic ion trajectories are captured from the sensor screen with an intensified charge-coupled detector camera. The spectrometer was designed and calibrated using the Geant4 toolkit, accounting for the effects on the ion trajectories of spatial non-uniformities in the spectrometer magnetic and electric fields. Results for hydrogen gas puffs indicate the existence of a class of accelerated protons with energies well above the coaxial discharge potential (up to 24 keV). The Thomson analyzer confirms the presence of impurities of copper and iron, also of relatively high energies, which are likely erosion or sputter products from plasma-electrode interactions.

  13. A Thomson-type mass and energy spectrometer for characterizing ion energy distributions in a coaxial plasma gun operating in a gas-puff mode.

    PubMed

    Rieker, G B; Poehlmann, F R; Cappelli, M A

    2013-07-01

    Measurements of ion energy distribution are performed in the accelerated plasma of a coaxial electromagnetic plasma gun operating in a gas-puff mode at relatively low discharge energy (900 J) and discharge potential (4 kV). The measurements are made using a Thomson-type mass and energy spectrometer with a gated microchannel plate and phosphor screen as the ion sensor. The parabolic ion trajectories are captured from the sensor screen with an intensified charge-coupled detector camera. The spectrometer was designed and calibrated using the Geant4 toolkit, accounting for the effects on the ion trajectories of spatial non-uniformities in the spectrometer magnetic and electric fields. Results for hydrogen gas puffs indicate the existence of a class of accelerated protons with energies well above the coaxial discharge potential (up to 24 keV). The Thomson analyzer confirms the presence of impurities of copper and iron, also of relatively high energies, which are likely erosion or sputter products from plasma-electrode interactions.

  14. A Thomson-type mass and energy spectrometer for characterizing ion energy distributions in a coaxial plasma gun operating in a gas-puff mode

    PubMed Central

    Rieker, G. B.; Poehlmann, F. R.; Cappelli, M. A.

    2013-01-01

    Measurements of ion energy distribution are performed in the accelerated plasma of a coaxial electromagnetic plasma gun operating in a gas-puff mode at relatively low discharge energy (900 J) and discharge potential (4 kV). The measurements are made using a Thomson-type mass and energy spectrometer with a gated microchannel plate and phosphor screen as the ion sensor. The parabolic ion trajectories are captured from the sensor screen with an intensified charge-coupled detector camera. The spectrometer was designed and calibrated using the Geant4 toolkit, accounting for the effects on the ion trajectories of spatial non-uniformities in the spectrometer magnetic and electric fields. Results for hydrogen gas puffs indicate the existence of a class of accelerated protons with energies well above the coaxial discharge potential (up to 24 keV). The Thomson analyzer confirms the presence of impurities of copper and iron, also of relatively high energies, which are likely erosion or sputter products from plasma-electrode interactions. PMID:23983449

  15. Energy loss in gas lasers operating in hollow-core optical fibers

    NASA Astrophysics Data System (ADS)

    Lane, Ryan A.; Madden, Timothy J.

    2017-03-01

    The output of solid core fiber lasers is constrained in the mid-infrared due to the absorption properties of silica. Optically pumped gas lasers can reach the mid-infrared but require long path lengths for interaction between the pump light and gain medium. Optically pumped gas lasers where the gain medium is contained in a hollow-core optical fiber may provide a robust and compact platform that combines advantages of fiber and optically-pumped gas lasers. Experimental demonstrations of gas-filled-fiber lasers have been reported. The energy output of a molecular gas laser operating in a hollow-core optical fiber is computationally modeled using rate equations. The rate equations include terms for various physical processes including molecular self-collisions, molecular collisions with the fiber walls, and fiber attenuation. The rate equations are solved for a time-dependent, one-dimensional fiber model with an acetylene gain medium that lases along rotation-vibrational transitions. The energy output and losses are computed for multiple configurations. Model correspondence with reported experiments is shown. The computed energy losses due to backwards propagating light, fiber losses, and molecular collisions are applied to pulsed, continuous wave, and synchronously pumped gas lasers operating in hollow-core optical fibers. Energy losses due to molecular collisions are used to estimate heating in the gain medium.

  16. The role of passive sampling in monitoring the environmental impacts of produced water discharges from the Norwegian oil and gas industry.

    PubMed

    Hale, Sarah E; Oen, Amy M P; Cornelissen, Gerard; Jonker, Michiel T O; Waarum, Ivar-Kristian; Eek, Espen

    2016-10-15

    Stringent and periodic iteration of regulations related to the monitoring of chemical releases from the offshore oil and gas industry requires the use of ever changing, rapidly developing and technologically advancing techniques. Passive samplers play an important role in water column monitoring of produced water (PW) discharge to seawater under Norwegian regulation, where they are used to; i) measure aqueous concentrations of pollutants, ii) quantify the exposure of caged organisms and investigate PW dispersal, and iii) validate dispersal models. This article summarises current Norwegian water column monitoring practice and identifies research and methodological gaps for the use of passive samplers in monitoring. The main gaps are; i) the range of passive samplers used should be extended, ii) differences observed in absolute concentrations accumulated by passive samplers and organisms should be understood, and iii) the link between PW discharge concentrations and observed acute and sub-lethal ecotoxicological end points in organisms should be investigated. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Operator splitting method for simulation of dynamic flows in natural gas pipeline networks

    SciTech Connect

    Dyachenko, Sergey A.; Zlotnik, Anatoly; Korotkevich, Alexander O.; Chertkov, Michael

    2017-09-19

    Here, we develop an operator splitting method to simulate flows of isothermal compressible natural gas over transmission pipelines. The method solves a system of nonlinear hyperbolic partial differential equations (PDEs) of hydrodynamic type for mass flow and pressure on a metric graph, where turbulent losses of momentum are modeled by phenomenological Darcy-Weisbach friction. Mass flow balance is maintained through the boundary conditions at the network nodes, where natural gas is injected or withdrawn from the system. Gas flow through the network is controlled by compressors boosting pressure at the inlet of the adjoint pipe. Our operator splitting numerical scheme is unconditionally stable and it is second order accurate in space and time. The scheme is explicit, and it is formulated to work with general networks with loops. We test the scheme over range of regimes and network configurations, also comparing its performance with performance of two other state of the art implicit schemes.

  18. Operator splitting method for simulation of dynamic flows in natural gas pipeline networks

    NASA Astrophysics Data System (ADS)

    Dyachenko, Sergey A.; Zlotnik, Anatoly; Korotkevich, Alexander O.; Chertkov, Michael

    2017-12-01

    We develop an operator splitting method to simulate flows of isothermal compressible natural gas over transmission pipelines. The method solves a system of nonlinear hyperbolic partial differential equations (PDEs) of hydrodynamic type for mass flow and pressure on a metric graph, where turbulent losses of momentum are modeled by phenomenological Darcy-Weisbach friction. Mass flow balance is maintained through the boundary conditions at the network nodes, where natural gas is injected or withdrawn from the system. Gas flow through the network is controlled by compressors boosting pressure at the inlet of the adjoint pipe. Our operator splitting numerical scheme is unconditionally stable and it is second order accurate in space and time. The scheme is explicit, and it is formulated to work with general networks with loops. We test the scheme over range of regimes and network configurations, also comparing its performance with performance of two other state of the art implicit schemes.

  19. Operator splitting method for simulation of dynamic flows in natural gas pipeline networks

    SciTech Connect

    Dyachenko, Sergey A.; Zlotnik, Anatoly; Korotkevich, Alexander O.

    2017-09-19

    Here, we develop an operator splitting method to simulate flows of isothermal compressible natural gas over transmission pipelines. The method solves a system of nonlinear hyperbolic partial differential equations (PDEs) of hydrodynamic type for mass flow and pressure on a metric graph, where turbulent losses of momentum are modeled by phenomenological Darcy-Weisbach friction. Mass flow balance is maintained through the boundary conditions at the network nodes, where natural gas is injected or withdrawn from the system. Gas flow through the network is controlled by compressors boosting pressure at the inlet of the adjoint pipe. Our operator splitting numerical scheme ismore » unconditionally stable and it is second order accurate in space and time. The scheme is explicit, and it is formulated to work with general networks with loops. We test the scheme over range of regimes and network configurations, also comparing its performance with performance of two other state of the art implicit schemes.« less

  20. Effect of operating parameters and anode gas impurities upon polymer electrolyte fuel cells

    SciTech Connect

    Weisbrod, K.R.; Vanderborgh, N.E.

    1994-07-01

    PEM fuel cells are actively under development for transportation and other applications. Integration of a PEM fuel cell stack with a methanol reformer requires an understanding of single cell performance under a range of operating conditions using anode gas contaminated with impurities. The effect of temperature, pressure, and anode gas impurities on single cell PEM performance was investigated with platinum black electrodes. Single cell performance remained unchanged as temperature was varied between 80 and 100 at 3 atm pressure. High water partial pressures at 120C produced a mass transfer limiting current. While operation at 120C did not reverse CO{sub 2} poisoning, anode air addition proved effective. Air injection also decreased CO poisoning at injected concentrations up to 200 ppm CO. Higher single cell tolerance was observed for CH{sub 3}OH than CO. Up to 1 mole % CH{sub 3}OH in the gas phase reduced the current density by less than 10%.

  1. Operation of an experimental algal gas exchanger for use in a CELSS

    NASA Technical Reports Server (NTRS)

    Smernoff, David T.; Wharton, Robert A., Jr.; Averner, Maurice M.

    1987-01-01

    Concepts of a CELSS anticipate the use of photosynthetic organisms for air revitalization. The rates of production and uptake of carbon dioxide and oxygen between the crew and the photosynthetic organisms are mismatched. An algal system used for gas exchange only will have the difficulty of an accumulation or depletion of these gases beyond physiologically tolerable limits. The results of a study designed to test the feasibility of using environmental manipulations to maintain physiologically appropriate atmospheres for algae (Chlorella pyrenoidosa) and mice (Mus musculus strain DW/J) in a gas-closed system is reported. Specifically, the atmosphere behavior of this system with Chlorella grown on nitrate or urea and at different light intensities and optical densities is considered. Manipulation of both the photosynthetic rate and the assimilatory quotient of the alga has been found to reduce the mismatch of gas requirements and allow operation of the system in a gas-stable manner.

  2. Some insights in novel risk modeling of liquefied natural gas carrier maintenance operations

    NASA Astrophysics Data System (ADS)

    Nwaoha, T. C.; John, Andrew

    2016-06-01

    This study discusses the analysis of various modeling approaches and maintenance techniques applicable to the Liquefied Natural Gas (LNG) carrier operations in the maritime environment. Various novel modeling techniques are discussed; including genetic algorithms, fuzzy logic and evidential reasoning. We also identify the usefulness of these algorithms in the LNG carrier industry in the areas of risk assessment and maintenance modeling.

  3. 75 FR 27340 - Energy Efficiency of Natural Gas Infrastructure and Operations Conference; Supplemental Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-14

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Energy Efficiency of Natural Gas Infrastructure and Operations Conference...) in the Commission Meeting Room at the Federal Energy Regulatory Commission, 888 First Street, NE...

  4. FUEL CELL OPERATION ON ANAEROBIC DIGESTER GAS: CONCEPTUAL DESIGN AND ASSESSMENT

    EPA Science Inventory

    The conceptual design of a fuel cell (FC) system for operation on anaerobic digester gas (ADG) is described and its economic and environmental feasibility is projected. ADG is produced at water treatment plants during the process of treating sewage anaerobically to reduce solids....

  5. Operating Gas-Absorbing Equipment. Module 21. Vocational Education Training in Environmental Health Sciences.

    ERIC Educational Resources Information Center

    Consumer Dynamics Inc., Rockville, MD.

    This module, one of 25 on vocational education training for careers in environmental health occupations, contains self-instructional materials on operating gas-absorbing equipment. Following guidelines for students and instructors and an introduction that explains what the student will learn are three lessons: (1) identifying parts and functions…

  6. 78 FR 75359 - Waterway Suitability Assessment for Construction and Operation of Liquefied Gas Terminals; Orange...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-11

    ..., 2011, the Coast Guard published Navigation and Vessel Inspection Circular (NVIC) 01-2011, ``Guidance Related to Waterfront Liquefied Natural Gas (LNG) Facilities.'' NVIC 01-2011 provides guidance for owners... LNG, it provides useful process information and guidance for owners and operators seeking approval to...

  7. Inductive gas line for pulsed lasers

    DOEpatents

    Benett, W.J.; Alger, T.W.

    1982-09-29

    A gas laser having a metal inlet gas feed line assembly shaped as a coil, to function as an electrical inductance and therefore high impedance to pulses of electric current applied to electrodes at opposite ends of a discharge tube of a laser, for example. This eliminates a discharge path for the laser through the inlet gas feed line. A ferrite core extends through the coil to increase the inductance of the coil and provide better electric isolation. By elimination of any discharge breakdown through the gas supply, efficiency is increased and a significantly longer operating lifetime of the laser is provided.

  8. Inductive gas line for pulsed lasers

    DOEpatents

    Benett, William J.; Alger, Terry W.

    1985-01-01

    A gas laser having a metal inlet gas feed line assembly shaped as a coil, to function as an electrical inductance and therefore high impedance to pulses of electric current applied to electrodes at opposite ends of a discharge tube of a laser, for example. This eliminates a discharge path for the laser through the inlet gas feed line. A ferrite core extends through the coil to increase the inductance of the coil and provide better electric isolation. By elimination of any discharge breakdown through the gas supply, efficiency is increased and a significantly longer operating lifetime of the laser is provided.

  9. Gallbladder removal - laparoscopic - discharge

    MedlinePlus

    Cholecystectomy laparoscopic - discharge; Cholelithiasis - laparoscopic discharge; Biliary calculus - laparoscopic discharge; Gallstones - laparoscopic discharge; Cholecystitis - laparoscopic discharge

  10. Recirculating rotary gas compressor

    DOEpatents

    Weinbrecht, John F.

    1992-01-01

    A positive displacement, recirculating Roots-type rotary gas compressor which operates on the basis of flow work compression. The compressor includes a pair of large diameter recirculation conduits (24 and 26) which return compressed discharge gas to the compressor housing (14), where it is mixed with low pressure inlet gas, thereby minimizing adiabatic heating of the gas. The compressor includes a pair of involutely lobed impellers (10 and 12) and an associated port configuration which together result in uninterrupted flow of recirculation gas. The large diameter recirculation conduits equalize gas flow velocities within the compressor and minimize gas flow losses. The compressor is particularly suited to applications requiring sustained operation at higher gas compression ratios than have previously been feasible with rotary pumps, and is particularly applicable to refrigeration or other applications requiring condensation of a vapor.

  11. Recirculating rotary gas compressor

    DOEpatents

    Weinbrecht, J.F.

    1992-02-25

    A positive displacement, recirculating Roots-type rotary gas compressor is described which operates on the basis of flow work compression. The compressor includes a pair of large diameter recirculation conduits which return compressed discharge gas to the compressor housing, where it is mixed with low pressure inlet gas, thereby minimizing adiabatic heating of the gas. The compressor includes a pair of involutely lobed impellers and an associated port configuration which together result in uninterrupted flow of recirculation gas. The large diameter recirculation conduits equalize gas flow velocities within the compressor and minimize gas flow losses. The compressor is particularly suited to applications requiring sustained operation at higher gas compression ratios than have previously been feasible with rotary pumps, and is particularly applicable to refrigeration or other applications requiring condensation of a vapor. 12 figs.

  12. Methane discharge from a deep-sea submarine mud volcano into the upper water column by gas hydrate-coated methane bubbles

    NASA Astrophysics Data System (ADS)

    Sauter, Eberhard J.; Muyakshin, Sergey I.; Charlou, Jean-Luc; Schlüter, Michael; Boetius, Antje; Jerosch, Kerstin; Damm, Ellen; Foucher, Jean-Paul; Klages, Michael

    2006-03-01

    The assessment of climate change factors includes a constraint of methane sources and sinks. Although marine geological sources are recognized as significant, unfortunately, most submarine sources remain poorly quantified. Beside cold vents and coastal anoxic sediments, the large number of submarine mud volcanoes (SMV) may contribute significantly to the oceanic methane pool. Recent research suggests that methane primarily released diffusively from deep-sea SMVs is immediately oxidized and, thus, has little climatic impact. New hydro-acoustic, visual, and geochemical observations performed at the deep-sea mud volcano Håkon Mosby reveal the discharge of gas hydrate-coated methane bubbles and gas hydrate flakes forming huge methane plumes extending from the seabed in 1250 m depth up to 750 m high into the water column. This depth coincides with the upper limit of the temperature-pressure field of gas hydrate stability. Hydrographic evidence suggests bubble-induced upwelling within the plume and extending above the hydrate stability zone. Thus, we propose that a significant portion of the methane from discharged methane bubbles can reach the upper water column, which may be explained due to the formation of hydrate skins. As the water mass of the plume rises to shallow water depths, methane dissolved from hydrated bubbles may be transported towards the surface and released to the atmosphere. Repeated acoustic surveys performed in 2002 and 2003 suggest continuous methane emission to the ocean. From seafloor visual observations we estimated a gas flux of 0.2 (0.08-0.36) mol s -1 which translates to several hundred tons yr -1 under the assumption of a steady discharge. Besides, methane was observed to be released by diffusion from sediments as well as by focused outflow of methane-rich water. In contrast to the bubble discharge, emission rates of these two pathways are estimated to be in the range of several tons yr -1 and, thus, to be of minor importance. Very low

  13. Formation of the active medium in high-power repetitively pulsed gas lasers pumped by an electron-beam-controlled discharge

    SciTech Connect

    Bulaev, V D; Lysenko, S L

    2015-07-31

    A high-power repetitively pulsed e-beam-controlled discharge CO{sub 2} laser is simulated numerically; the simulation results are compared with experimental data. Optimal sizes and design of electrodes and configuration of the external magnetic field are found, which allow one to introduce no less than 90% electric pump energy into a specified volume of the active medium, including the active volume of a laser with an aperture of 110 × 110 cm. The results obtained can also be used to design other types of highpower gas lasers. (lasers)

  14. Formation of the active medium in high-power repetitively pulsed gas lasers pumped by an electron-beam-controlled discharge

    NASA Astrophysics Data System (ADS)

    Bulaev, V. D.; Lysenko, S. L.

    2015-07-01

    A high-power repetitively pulsed e-beam-controlled discharge CO2 laser is simulated numerically; the simulation results are compared with experimental data. Optimal sizes and design of electrodes and configuration of the external magnetic field are found, which allow one to introduce no less than 90% electric pump energy into a specified volume of the active medium, including the active volume of a laser with an aperture of 110 × 110 cm. The results obtained can also be used to design other types of highpower gas lasers.

  15. Supporting inland waterway transport on German waterways by operational forecasting services - water-levels, discharges, river ice

    NASA Astrophysics Data System (ADS)

    Meißner, Dennis; Klein, Bastian; Ionita, Monica; Hemri, Stephan; Rademacher, Silke

    2017-04-01

    Inland waterway transport (IWT) is an important commercial sector significantly vulnerable to hydrological impacts. River ice and floods limit the availability of the waterway network and may cause considerable damages to waterway infrastructure. Low flows significantly affect IWT's operation efficiency usually several months a year due to the close correlation of (low) water levels / water depths and (high) transport costs. Therefore "navigation-related" hydrological forecasts focussing on the specific requirements of water-bound transport (relevant forecast locations, target parameters, skill characteristics etc.) play a major role in order to mitigate IWT's vulnerability to hydro-meteorological impacts. In light of continuing transport growth within the European Union, hydrological forecasts for the waterways are essential to stimulate the use of the free capacity IWT still offers more consequently. An overview of the current operational and pre-operational forecasting systems for the German waterways predicting water levels, discharges and river ice thickness on various time-scales will be presented. While short-term (deterministic) forecasts have a long tradition in navigation-related forecasting, (probabilistic) forecasting services offering extended lead-times are not yet well-established and are still subject to current research and development activities (e.g. within the EU-projects EUPORIAS and IMPREX). The focus is on improving technical aspects as well as on exploring adequate ways of disseminating and communicating probabilistic forecast information. For the German stretch of the River Rhine, one of the most frequented inland waterways worldwide, the existing deterministic forecast scheme has been extended by ensemble forecasts combined with statistical post-processing modules applying EMOS (Ensemble Model Output Statistics) and ECC (Ensemble Copula Coupling) in order to generate water level predictions up to 10 days and to estimate its predictive

  16. New tracers identify hydraulic fracturing fluids and accidental releases from oil and gas operations.

    PubMed

    Warner, N R; Darrah, T H; Jackson, R B; Millot, R; Kloppmann, W; Vengosh, A

    2014-11-04

    Identifying the geochemical fingerprints of fluids that return to the surface after high volume hydraulic fracturing of unconventional oil and gas reservoirs has important applications for assessing hydrocarbon resource recovery, environmental impacts, and wastewater treatment and disposal. Here, we report for the first time, novel diagnostic elemental and isotopic signatures (B/Cl, Li/Cl, δ11B, and δ7Li) useful for characterizing hydraulic fracturing flowback fluids (HFFF) and distinguishing sources of HFFF in the environment. Data from 39 HFFFs and produced water samples show that B/Cl (>0.001), Li/Cl (>0.002), δ11B (25-31‰) and δ7Li (6-10‰) compositions of HFFF from the Marcellus and Fayetteville black shale formations were distinct in most cases from produced waters sampled from conventional oil and gas wells. We posit that boron isotope geochemistry can be used to quantify small fractions (∼0.1%) of HFFF in contaminated fresh water and likely be applied universally to trace HFFF in other basins. The novel environmental application of this diagnostic isotopic tool is validated by examining the composition of effluent discharge from an oil and gas brine treatment facility in Pennsylvania and an accidental spill site in West Virginia. We hypothesize that the boron and lithium are mobilized from exchangeable sites on clay minerals in the shale formations during the hydraulic fracturing process, resulting in the relative enrichment of boron and lithium in HFFF.

  17. 33 CFR 165.110 - Safety and Security Zone; Liquefied Natural Gas Carrier Transits and Anchorage Operations, Boston...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...; Liquefied Natural Gas Carrier Transits and Anchorage Operations, Boston, Massachusetts. 165.110 Section 165... Limited Access Areas First Coast Guard District § 165.110 Safety and Security Zone; Liquefied Natural Gas... ahead and one mile astern, and 500 yards on each side of any liquefied natural gas carrier (LNGC) vessel...

  18. Wintertime Air Quality Impacts from Oil and Natural Gas Drilling Operations in the Bakken Formation Region

    NASA Astrophysics Data System (ADS)

    Evanoski-Cole, Ashley; Sive, Barkley; Zhou, Yong; Prenni, Anthony; Schurman, Misha; Day, Derek; Sullivan, Amy; Li, Yi; Hand, Jenny; Gebhart, Kristi; Schichtel, Bret; Collett, Jeffrey

    2016-04-01

    Oil and natural gas extraction has dramatically increased in the last decade in the United States due to the increased use of unconventional drilling techniques which include horizontal drilling and hydraulic fracturing. The impact of these drilling activities on local and regional air quality in oil and gas basins across the country are still relatively unknown, especially in recently developed basins such as the Bakken shale formation. This study is the first to conduct a comprehensive characterization of the regional air quality in the Bakken region. The Bakken shale formation, part of the Williston basin, is located in North Dakota and Montana in the United States and Saskatchewan and Manitoba in Canada. Oil and gas drilling operations can impact air quality in a variety of ways, including the generation of atmospheric particulate matter (PM), hazardous air pollutants, ozone, and greenhouse gas emissions. During the winter especially, PM formation can be enhanced and meteorological conditions can favor increased concentrations of PM and other pollutants. In this study, ground-based measurements throughout the Bakken region in North Dakota and Montana were collected over two consecutive winters to gain regional trends of air quality impacts from the oil and gas drilling activities. Additionally, one field site had a comprehensive suite of instrumentation operating at high time resolution to gain detailed characterization of the atmospheric composition. Measurements included organic carbon and black carbon concentrations in PM, the characterization of inorganic PM, inorganic gases, volatile organic compounds (VOCs), precipitation and meteorology. These elevated PM episodes were further investigated using the local meteorological conditions and regional transport patterns. Episodes of elevated concentrations of nitrogen oxides and sulfur dioxide were also detected. The VOC concentrations were analyzed and specific VOCs that are known oil and gas tracers were used

  19. 33 CFR 165.1709 - Security Zones: Liquefied Natural Gas Tanker Transits and Operations at Phillips Petroleum LNG...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Gas Tanker Transits and Operations at Phillips Petroleum LNG Pier, Cook Inlet, AK. 165.1709 Section...: Liquefied Natural Gas Tanker Transits and Operations at Phillips Petroleum LNG Pier, Cook Inlet, AK. (a... and outbound transits through Cook Inlet, Alaska between the Phillips Petroleum LNG Pier, 60°40′43″ N...

  20. 33 CFR 165.1709 - Security Zones: Liquefied Natural Gas Tanker Transits and Operations at Phillips Petroleum LNG...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Gas Tanker Transits and Operations at Phillips Petroleum LNG Pier, Cook Inlet, AK. 165.1709 Section...: Liquefied Natural Gas Tanker Transits and Operations at Phillips Petroleum LNG Pier, Cook Inlet, AK. (a... and outbound transits through Cook Inlet, Alaska between the Phillips Petroleum LNG Pier, 60°40′43″ N...

  1. 33 CFR 165.1709 - Security Zones: Liquefied Natural Gas Tanker Transits and Operations at Phillips Petroleum LNG...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Gas Tanker Transits and Operations at Phillips Petroleum LNG Pier, Cook Inlet, AK. 165.1709 Section...: Liquefied Natural Gas Tanker Transits and Operations at Phillips Petroleum LNG Pier, Cook Inlet, AK. (a... and outbound transits through Cook Inlet, Alaska between the Phillips Petroleum LNG Pier, 60°40′43″ N...

  2. 25 CFR 215.23a - Suspension of operations and production on leases for minerals other than oil and gas.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... minerals other than oil and gas. 215.23a Section 215.23a Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEAD AND ZINC MINING OPERATIONS AND LEASES, QUAPAW AGENCY § 215.23a Suspension of operations and production on leases for minerals other than oil and gas. The provisions of...

  3. 25 CFR 215.23a - Suspension of operations and production on leases for minerals other than oil and gas.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... minerals other than oil and gas. 215.23a Section 215.23a Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEAD AND ZINC MINING OPERATIONS AND LEASES, QUAPAW AGENCY § 215.23a Suspension of operations and production on leases for minerals other than oil and gas. The provisions of...

  4. 25 CFR 215.23a - Suspension of operations and production on leases for minerals other than oil and gas.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... minerals other than oil and gas. 215.23a Section 215.23a Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEAD AND ZINC MINING OPERATIONS AND LEASES, QUAPAW AGENCY § 215.23a Suspension of operations and production on leases for minerals other than oil and gas. The provisions of...

  5. 25 CFR 215.23a - Suspension of operations and production on leases for minerals other than oil and gas.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... minerals other than oil and gas. 215.23a Section 215.23a Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEAD AND ZINC MINING OPERATIONS AND LEASES, QUAPAW AGENCY § 215.23a Suspension of operations and production on leases for minerals other than oil and gas. The provisions of...

  6. 25 CFR 215.23a - Suspension of operations and production on leases for minerals other than oil and gas.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... minerals other than oil and gas. 215.23a Section 215.23a Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEAD AND ZINC MINING OPERATIONS AND LEASES, QUAPAW AGENCY § 215.23a Suspension of operations and production on leases for minerals other than oil and gas. The provisions of...

  7. Mercury isotope signatures of seawater discharged from a coal-fired power plant equipped with a seawater flue gas desulfurization system.

    PubMed

    Lin, Haiying; Peng, Jingji; Yuan, Dongxing; Lu, Bingyan; Lin, Kunning; Huang, Shuyuan

    2016-07-01

    Seawater flue gas desulfurization (SFGD) systems are commonly used to remove acidic SO2 from the flue gas with alkaline seawater in many coastal coal-fired power plants in China. However, large amount of mercury (Hg) originated from coal is also transferred into seawater during the desulfurization (De-SO2) process. This research investigated Hg isotopes in seawater discharged from a coastal plant equipped with a SFGD system for the first time. Suspended particles of inorganic minerals, carbon residuals and sulfides are enriched in heavy Hg isotopes during the De-SO2 process. δ(202)Hg of particulate mercury (PHg) gradually decreased from -0.30‰ to -1.53‰ in study sea area as the distance from the point of discharge increased. The results revealed that physical mixing of contaminated De-SO2 seawater and uncontaminated fresh seawater caused a change in isotopic composition of PHg isotopes in the discharging area; and suggested that both De-SO2 seawater and local background contributed to PHg. The impacted sea area predicted with isotopic tracing technique was much larger than that resulted from a simple comparison of pollutant concentration. It was the first attempt to apply mercury isotopic composition signatures with two-component mixing model to trace the mercury pollution and its influence in seawater. The results could be beneficial to the coal-fired plants with SFGD systems to assess and control Hg pollution in sea area. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Investigation of the Discharge Characteristics of the T6 Hollow Cathode Operating on Several Inert Gases and a Kr/Xe Mixture

    NASA Astrophysics Data System (ADS)

    Ahmed Rudwan, M.; Gabriel, S. B.

    2002-01-01

    Investigation of the discharge characteristics of the T6 hollow cathode operating on several inert Xenon is currently the propellant of choice for gridded ion thrusters. But in order to make deep space missions feasible, an increase in the Specific Impulse (SI) that these thrusters can achieve is necessary. One method of achieving this is to use a propellant with a lower atomic mass (e.g. argon), as the propellant exhaust velocity is inversely proportional to the square root of the propellant mass. However, the feasibility of operating the hollow cathode using these alternative propellants has to be demonstrated. Moreover, interest in decreasing the propellant cost in missions and ground testing (especially life tests) have led to the comprehensive discharge characterisation of several gases that will be presented in this paper. A Kr/Xe mixture in the naturally occurring ratio, for example, could offer a 15 times cost saving when compared to pure xenon and 2-3 times cost saving when compared to pure krypton. The T6 hollow cathode discharge behaviour as well as its initiation characteristics have been studied. The tests were carried out in diode configuration using a T6 hollow cathode with an enclosed keeper design employing xenon, krypton, argon and a Kr/Xe mix. The discharge initiation tests were undertaken with a view to investigate some of the factors thought to influence the starting potential such as mass flow rate and tip temperature. It was found that, for mass flow rates ranging from 0.2-1.1 mg/s and cathode tip temperatures ranging from 900-1300oC, the breakdown potential was less than 50V for argon, less than 25V for krypton, less than 21V for xenon and less than 35V for the Kr/Xe mix. The discharge initiation results were then compared to those obtained by Fearn et al. with a T5 cathode operating on mercury and with a T6 cathode utilising an open keeper design using xenon propellant. The xenon breakdown potentials were found to be lower than those

  9. Fluid Mechanical Refracting Gas Prism And Aerodynamics of E-Beam Sustained Discharge in Supersonic Flow, Both Applicable to Laser Technology

    DTIC Science & Technology

    1979-04-01

    nozzle profile are well known. For reasonable Venus Machine dimensions, Ref. 9 shows that two-dimensional solutions given a good approximation to the...flow. Thus, given a Venus Machine nozzle profile , the operating gas, and the nozzle stagnation conditions, the n and nr fields can readily be calculated

  10. Clinical, operational and economic outcomes of point-of-care blood gas analysis in COPD patients.

    PubMed

    Oliver, Paloma; Buno, Antonio; Alvarez-Sala, Rodolfo; Fernandez-Calle, Pilar; Alcaide, Maria Jose; Casitas, Raquel; Garcia-Quero, Cristina; Madero, Rosario; Gomez-Rioja, Ruben; Iturzaeta, Jose Manuel

    2015-04-01

    Arterial blood gas analysis is relevant in chronic obstructive pulmonary disease (COPD) management. The aim of this study was to evaluate whether the use of a blood gas analyzer in pulmonology departments improves the clinical, operational and economic outcomes when compared with clinical laboratory measurements. It is an observational prospective study. 112 patients were selected. After specimen collection, the measurement was performed both in pulmonology office as point-of-care and in laboratory. We evaluated clinical outcomes (modification of the indication of long-term oxygen therapy (LTOT) according to results, changes in blood gas analysis results, relationship of the partial pressure of oxygen (PaO2) obtained in the medical visit and velocity of change of the PaO2, influence of total haemoglobin concentration and the change in PaO2), operational outcomes (turnaround time (TAT) from specimen collection to receiving the blood gas analysis report) and economic outcomes (overall cost per process of patient care). There were discrepancies in the indication of LTOT in 13.4% of patients. All parameters showed changes. PaO2 levels showed changes in 2 ways, though they frequently increase over time. The correlation was not good in the other two clinical outcomes. The median TATs in pulmonology office were 1 min versus 79 in laboratory, with 52 min for specimen preparation and transport and 17 min for TAT intralaboratory. The overall cost for the 112 patients in pulmonology office and laboratory was 16,769.89€ and 22,260.97€ respectively. The use of a blood gas analyzer in a pulmonology office improves clinical, operational and economic outcomes when compared with clinical laboratory. Copyright © 2014 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  11. Fatal injuries in offshore oil and gas operations - United States, 2003-2010.

    PubMed

    2013-04-26

    During 2003-2010, the U.S. oil and gas extraction industry (onshore and offshore, combined) had a collective fatality rate seven times higher than for all U.S. workers (27.1 versus 3.8 deaths per 100,000 workers). The 11 lives lost in the 2010 Deepwater Horizon explosion provide a reminder of the hazards involved in offshore drilling. To identify risk factors to offshore oil and gas extraction workers, CDC analyzed data from the Bureau of Labor Statistics (BLS) Census of Fatal Occupational Injuries (CFOI), a comprehensive database of fatal work injuries, for the period 2003-2010. This report describes the results of that analysis, which found that 128 fatalities in activities related to offshore oil and gas operations occurred during this period. Transportation events were the leading cause (65 [51%]); the majority of these involved aircraft (49 [75%]). Nearly one fourth (31 [24%]) of the fatalities occurred among workers whose occupations were classified as "transportation and material moving." To reduce fatalities in offshore oil and gas operations, employers should ensure that the most stringent applicable transportation safety guidelines are followed.

  12. Improved operation of a microwave pulse compressor with a laser-triggered high-pressure gas plasma switch

    SciTech Connect

    Shlapakovski, A.; Gorev, S.; Krasik, Ya. E.

    2016-08-15

    The influence of laser beam parameters on the output pulses of a resonant microwave compressor with a laser-triggered plasma switch was investigated. The S-band compressor, consisting of a rectangular waveguide-based cavity and H-plane waveguide tee with a shorted side arm, was filled with pressurized dry air and pumped by 1.8-μs-long microwave pulses of up to 450 kW power. A Nd:YAG laser was used to ignite the gas discharge in the tee side arm for output pulse extraction. The laser beam (at 213 nm or 532 nm) was directed along the RF electric field lines. It was found that the compressor operated most effectively when the laser beam was focused at the center of the switch waveguide cross-section. In this case, the power extraction efficiency reached ∼47% at an output power of ∼14 MW, while when the laser beam was not focused the maximal extraction efficiency was only ∼20% at ∼6 MW output power. Focusing the laser beam resulted also in a dramatic decrease (down to <1 ns) in the delay of the output pulses' appearance with respect to the time of the beam's entrance into the switch, and the jitter of the output pulses' appearance was minimized. In addition, the quality of the output pulses' waveform was significantly improved.

  13. Improved operation of a microwave pulse compressor with a laser-triggered high-pressure gas plasma switch

    SciTech Connect

    Shlapakovski, A.; Gorev, S.; Krasik, Ya. E.

    2016-08-15

    The influence of laser beam parameters on the output pulses of a resonant microwave compressor with a laser-triggered plasma switch was investigated. The S-band compressor, consisting of a rectangular waveguide-based cavity and H-plane waveguide tee with a shorted side arm, was filled with pressurized dry air and pumped by 1.8-μs-long microwave pulses of up to 450 kW power. A Nd:YAG laser was used to ignite the gas discharge in the tee side arm for output pulse extraction. The laser beam (at 213 nm or 532 nm) was directed along the RF electric field lines. It was found that the compressor operated most effectivelymore » when the laser beam was focused at the center of the switch waveguide cross-section. In this case, the power extraction efficiency reached ∼47% at an output power of ∼14 MW, while when the laser beam was not focused the maximal extraction efficiency was only ∼20% at ∼6 MW output power. Focusing the laser beam resulted also in a dramatic decrease (down to <1 ns) in the delay of the output pulses' appearance with respect to the time of the beam's entrance into the switch, and the jitter of the output pulses' appearance was minimized. In addition, the quality of the output pulses' waveform was significantly improved.« less

  14. Thermal analysis of high pressure micro plasma discharge

    NASA Astrophysics Data System (ADS)

    Mobli, Mostafa

    High pressure micro plasma discharge has been at the center of interest in recent years, because of their vast applications, ease of access and cost efficiency. This attributes to atmospheric discharges that are generated in ambient conditions and therefore can be readily applicable to everyday use. The absence of vacuum makes these high pressure discharges to be inexpensive to operate. Despite the ease of operation, the high pressure is a source of enhanced gas heating as the gas temperature cannot be controlled by diffusion alone. Gas heating is therefore an important factor when it comes to the simulation of high pressure micro plasma discharge, unlike their low pressure counterpart where the heat generation is almost negligible. Low pressure discharge due to their low degree of collisionality generates ionic species and electrons at small concentrations, whereas high pressure discharge due to their higher gas density produces ions and electrons at higher concentrations which is a direct consequence of increase collision. The higher gas density and consequential large concentration of ionic species and electron contributes directly to higher heat generation rates. . In this thesis the gas temperature transport of high pressure micro plasma discharge has been studied with a special focus on the heat source terms, temperature boundary conditions, temperature distribution in the solid phase electrodes and the gas phase and their overall influence on the plasma characteristics. For this purpose a multi-physics mathematical model has been developed that comprised of a plasma module, neutral gas temperature module, external circuit module and conjugate heat transfer module. The plasma module consisted of conservation of the different ionic, electronically excited species, radicals, neutrals and electrons, conservation of the electron temperature, and electric field. The external circuit module resolved the coupled driving circuit comprised of a voltage source, ballast

  15. Special considerations on operating a fuel cell power plant using natural gas with marginal heating value

    SciTech Connect

    Moses, L. Ng; Chien-Liang Lin; Ya-Tang Cheng

    1996-12-31

    In realizing new power generation technologies in Taiwan, a phosphoric acid fuel cell power plant (model PC2513, ONSI Corporation) has been installed in the premises of the Power Research Institute of the Taiwan Power Company in Taipei County of Taiwan. The pipeline gas supplying to the site of this power plant has a high percentage of carbon dioxide and thus a slightly lower heating value than that specified by the manufacturer. Because of the lowering of heating value of input gas, the highest Output power from the power plant is understandably less than the rated power of 200 kW designed. Further, the transient response of the power plant as interrupted from the Grid is also affected. Since this gas is also the pipeline gas supplying to the heavily populated Taipei Municipal area, it is conceivable that the success of the operations of fuel cells using this fuel is of vital importance to the promotion of the use of this power generation technology in Taiwan. Hence, experiments were set up to assess the feasibility of this fuel cell power plant using the existing pipeline gas in this part of Taiwan where fuel cells would most likely find useful.

  16. Special considerations on operating a fuel cell power plant using natural gas with marginal heating value

    SciTech Connect

    Moses, L. Ng; Chien-Liang Lin; Ya-Tang Cheng

    1996-12-31

    In realizing new power generation technologies in Taiwan, a phosphoric acid fuel cell power plant (model PC2513, ONSI Corporation) has been installed in the premises of the Power Research Institute of the Taiwan Power Company in Taipei County of Taiwan. The pipeline gas supplying to the site of this power plant has a high percentage of carbon dioxide and thus a slightly lower heating value than that specified by the manufacturer. Because of the lowering of heating value of input gas, the highest Output power from the power plant is understandably less than the rated power of 200 kW designed.more » Further, the transient response of the power plant as interrupted from the Grid is also affected. Since this gas is also the pipeline gas supplying to the heavily populated Taipei Municipal area, it is conceivable that the success of the operations of fuel cells using this fuel is of vital importance to the promotion of the use of this power generation technology in Taiwan. Hence, experiments were set up to assess the feasibility of this fuel cell power plant using the existing pipeline gas in this part of Taiwan where fuel cells would most likely find useful.« less

  17. The relationship between methane migration and shale-gas well operations near Dimock, Pennsylvania, USA

    NASA Astrophysics Data System (ADS)

    Hammond, Patrick A.

    2016-03-01

    Migration of stray methane gas near the town of Dimock, Pennsylvania, has been at the center of the debate on the safety of shale gas drilling and hydraulic fracturing in the United States. The presented study relates temporal variations in molecular concentrations and stable isotope compositions of methane and ethane to shale-gas well activity (i.e., vertical/horizontal drilling, hydraulic fracturing and remedial actions). This was accomplished by analyzing data collected, between 2008 and 2012, by state and federal agencies and the gas well operator. In some cases, methane migration started prior to hydraulic fracturing. Methane levels of contaminated water wells sampled were one to several orders of magnitude greater than the concentrations due to natural variation in water wells of the local area. Isotope analyses indicate that all samples had a thermogenic origin at varying maturity levels, but from formations above the hydraulically fractured Marcellus Shale. The results from the initial water well samples were similar to annular gas values, but not those of production gases. This indicates that leakage by casing cement seals most likely caused the impacts, not breaks in the production casing walls. Remediation by squeeze cementing was partially effective in mitigating impacts of gas migration. In several cases where remediation caused a substantial reduction in methane levels, there were also substantial changes in the isotope values, providing evidence of two sources, one natural and the other man-induced. Sampling water wells while venting gas wells appears to be a cost-effective method for determining if methane migration has occurred.

  18. Operation of an experimental algal gas exchanger for use in a CELSS

    NASA Technical Reports Server (NTRS)

    Smernoff, David T.; Wharton, Robert A., Jr.; Averner, Maurice M.

    1987-01-01

    Concepts of a Closed Ecological Life Support System (CELSS) anticipate the use of photosynthetic organisms (higher plants and algae) for air revitalization. The rates of production and uptake of carbon dioxide and oxygen between the crew and the photosynthetic organisms are mismatched. An algal system used for gas exchange only will have the difficulty of an accumulation or depletion of these gases beyond physiologically tolerable limits (in a closed system the mismatch between assimilatory quotient (AQ) and respiratory quotient (RQ) is balanced by the operation of the waste processor). The results are given of a study designed to test the feasibility of using environmental manipulations to maintain physiologically appropriate atmospheres for algae and mice in a gas closed system. Specifically, the atmosphere behavior of this system is considered with algae grown on nitrate or urea and at different light intensities and optical densities. Manipulation of both allow operation of the system in a gas stable manner. Operation of such a system in a CELSS may be useful for reduction of buffer sizes, as a backup system for higher plant air revitalization and to supply extra oxygen to the waste processor or during crew changes.

  19. [CONSULTENOS: hospital discharge information programmes. Development and results from the first year of operation in 5 hospitals].

    PubMed

    Pardo López, M A; Aznar Saliente, M T; Soler Company, E

    2008-01-01

    The increased number of adverse effects from medicines occurring due to various discrepancies and medication errors at the time of a patient's discharge from hospital has lead us to develop measures to resolve these issues. The aim of this study is to present the methodology and design of a hospital discharge information programme and to describe the most representative findings. A common methodology was established and patients from 5 different hospitals were included in a hospital discharge information programme. An informative interview was carried out at the time of discharge and oral and written information was given regarding the patient's complete treatment at that point. After 7 days a follow up telephone call was made to assess our intervention. The information was collated and the patients' satisfaction with the programme was measured. 6,198 patients were included in the programme, 4,955 (79.86%) were informed. 6,454 interventions were carried out (980 to improve the efficiency of treatment, 531 the efficiency of safety, 4,770 informative interventions and 107 directed at other levels of care). Seven days later 4174 patients were contacted. 14.53% presented a problem with their medications, 8.96% had solved the problem by the time the call was made and 4.4% found that the instructions given to them at the time of being discharged from hospital helped them to solve the problem. There was a high level of satisfaction with the service (4.64 points out of 5). It is possible to develop a hospital discharge information programme as a care service. A high level of satisfaction has been achieved and safety has improved with regards the use of medication.

  20. 76 FR 12730 - Notice of Issuance of Federal Operating Permit to Great Lakes Gas Transmission Limited Partnership

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-08

    ...This notice announces that, on January, 28, 2011, pursuant to Title V of the Clean Air Act, EPA issued a Title V Permit to Operate (Title V permit) to Great Lakes Gas Transmission Limited Partnership (Great Lakes Gas). This permit authorizes Great Lakes Gas to operate three natural gas-fired turbine/compressors and one natural gas-fired standby electrical generator at Compressor Station 5 (CS5) in Cloquet, Minnesota. CS5, which is located on privately-owned fee land within the exterior boundaries of the Fond du Lac Band of Lake Superior Chippewa Indian Reservation, adds pressure to natural gas in Great Lakes' pipeline, causing the natural gas to flow to the next compressor station.

  1. Glow discharge detector

    DOEpatents

    Koo, Jackson C.; Yu, Conrad M.

    2002-01-01

    A highly sensitive electronic ion cell for the measurement of trace elements in He carrier gas which involves glow discharge. A constant wave (CW) glow discharge detector which is controlled through a biased resistor, can detect the change of electron density caused by impurities in the He carrier gas by many orders of magnitude larger than that caused by direct ionization or electron capture. The glow discharge detector utilizes a floating pseudo-electrode to form a probe in or near the plasma. By using this probe, the large variation of electron density due to trace amounts of impurities can be directly measured.

  2. Absorption measurements on a low-pressure, inductively coupled, argon - mercury discharge for lighting purposes: 1. The gas temperature and argon metastable states density

    NASA Astrophysics Data System (ADS)

    Jonkers, J.; Bakker, M.; van der Mullen, J. A. M.

    1997-07-01

    The gas temperature and the absolute density of the argon 0022-3727/30/13/015/img2 level in an 80 W inductively coupled low-pressure argon - mercury plasma are determined for three different argon filling pressures. This is done by measuring the line profile of the 0022-3727/30/13/015/img3 transition in argon, using a tuneable laser diode. Since the width of this argon line is found to depend on the kinetic heavy particle temperature only, radial profiles of the gas temperature can be obtained. It turns out that the maximum gas temperature in this discharge (550 - 810 K depending on the filling pressure) is significantly higher than that in a common tubular fluorescent lamp. From the radial distribution of the argon 4s density it can be concluded that the maxima of the electron density and of the electron temperature are situated close to the coil. It is also found that the position of these maxima depends on the argon filling pressure.

  3. Operational trace gas column observations from GOME-2 on MetOp

    NASA Astrophysics Data System (ADS)

    Valks, Pieter; Hao, Nan; Pinardi, Gaia; Hedelt, Pascal; Liu, Song; Van Roozendael, Michel; De Smedt, Isabelle; Theys, Nicolas; Koukouli, MariLiza; Balis, Dimitris

    2017-04-01

    This contribution focuses on the operational GOME-2 trace gas column products developed in the framework of EUMETSAT's Satellite Application Facility on Atmospheric Composition Monitoring (AC-SAF). We present an overview of the retrieval algorithms for ozone, OClO, NO2, SO2 and formaldehyde, and we show examples of various applications such as air quality and climate monitoring, using observations from the GOME-2 instruments on MetOp-A and MetOp-B. Total ozone and the minor trace gas columns from GOME-2 are retrieved with the latest version 4.8 of the GOME Data Processor (GDP), which uses an optimized Differential Optical Absorption Spectroscopy (DOAS) algorithm, with air mass factor conversions based on the LIDORT model. Improved total and tropospheric NO2 columns are retrieved in the visible wavelength region between 425 and 497 nm. SO2 emissions from volcanic and anthropogenic sources can be measured by GOME-2 using the UV wavelength region around 320 nm. For formaldehyde, an optimal DOAS fitting window around 335 nm has been determined for GOME-2. The GOME-2 trace gas columns have reached the operational EUMETSAT product status, and are available to the users in near real time (within two hours after sensing by GOME-2). The use of trace gas observations from the GOME-2 instruments on MetOp-A and MetOp-B for air quality purposed will be illustrated, e.g. for South-East Asia and Europe. Furthermore, comparisons of the GOME-2 satellite observations with ground-based measurements will be shown. Finally, the use of GOME-2 trace-gas column data in the Copernicus Atmosphere Monitoring Service (CAMS) will be presented.

  4. The Assessment of Instruments for Detecting Surface Water Spills Associated with Oil and Gas Operations

    SciTech Connect

    Harris, Aubrey E.; Hopkinson, Leslie; Soeder, Daniel

    2016-12-02

    Surface water and groundwater risks associated with unconventional oil and gas development result from potential spills of the large volumes of chemicals stored on-site during drilling and hydraulic fracturing operations, and the return to the surface of significant quantities of saline water produced during oil or gas well production. To better identify and mitigate risks, watershed models and tools are needed to evaluate the dispersion of pollutants in possible spill scenarios. This information may be used to determine the placement of in-stream water-quality monitoring instruments and to develop early-warning systems and emergency plans. A chemical dispersion model has been usedmore » to estimate the contaminant signal for in-stream measurements. Spills associated with oil and gas operations were identified within the Susquehanna River Basin Commission’s Remote Water Quality Monitoring Network. The volume of some contaminants was found to be sufficient to affect the water quality of certain drainage areas. The most commonly spilled compounds and expected peak concentrations at monitoring stations were used in laboratory experiments to determine if a signal could be detected and positively identified using standard water-quality monitoring equipment. The results were compared to historical data and baseline observations of water quality parameters, and showed that the chemicals tested do commonly affect water quality parameters. This work is an effort to demonstrate that hydrologic and water quality models may be applied to improve the placement of in-stream water quality monitoring devices. This information may increase the capability of early-warning systems to alert community health and environmental agencies of surface water spills associated with unconventional oil and gas operations.« less

  5. The Assessment of Instruments for Detecting Surface Water Spills Associated with Oil and Gas Operations

    SciTech Connect

    Harris, Aubrey E.; Hopkinson, Leslie; Soeder, Daniel

    2016-12-02

    Surface water and groundwater risks associated with unconventional oil and gas development result from potential spills of the large volumes of chemicals stored on-site during drilling and hydraulic fracturing operations, and the return to the surface of significant quantities of saline water produced during oil or gas well production. To better identify and mitigate risks, watershed models and tools are needed to evaluate the dispersion of pollutants in possible spill scenarios. This information may be used to determine the placement of in-stream water-quality monitoring instruments and to develop early-warning systems and emergency plans. A chemical dispersion model has been used to estimate the contaminant signal for in-stream measurements. Spills associated with oil and gas operations were identified within the Susquehanna River Basin Commission’s Remote Water Quality Monitoring Network. The volume of some contaminants was found to be sufficient to affect the water quality of certain drainage areas. The most commonly spilled compounds and expected peak concentrations at monitoring stations were used in laboratory experiments to determine if a signal could be detected and positively identified using standard water-quality monitoring equipment. The results were compared to historical data and baseline observations of water quality parameters, and showed that the chemicals tested do commonly affect water quality parameters. This work is an effort to demonstrate that hydrologic and water quality models may be applied to improve the placement of in-stream water quality monitoring devices. This information may increase the capability of early-warning systems to alert community health and environmental agencies of surface water spills associated with unconventional oil and gas operations.

  6. 40 CFR Appendix B to Part 434 - Baseline Determination and Compliance Monitoring for Pre-existing Discharges at Remining Operations

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) COAL... 40 Protection of Environment 31 2012-07-01 2012-07-01 false Baseline Determination and Compliance... to be used for establishing effluent limitations for pre-existing discharges at coal remining...

  7. 40 CFR Appendix B to Part 434 - Baseline Determination and Compliance Monitoring for Pre-existing Discharges at Remining Operations

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) COAL... 40 Protection of Environment 30 2014-07-01 2014-07-01 false Baseline Determination and Compliance... to be used for establishing effluent limitations for pre-existing discharges at coal remining...

  8. 40 CFR Appendix B to Part 434 - Baseline Determination and Compliance Monitoring for Pre-existing Discharges at Remining Operations

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) COAL... 40 Protection of Environment 31 2013-07-01 2013-07-01 false Baseline Determination and Compliance... to be used for establishing effluent limitations for pre-existing discharges at coal remining...

  9. Frequency of oral mucosa micronuclei in gas station operators after introducing methanol.

    PubMed

    Gattás, G J; Cardoso, L de A; Medrado-Faria, M de A; Saldanha, P H

    2001-03-01

    Methanol has been proposed in different countries as an alternative automotive fuel to be used as an additive to, or replacement for, gasoline or ethanol. Utilization of methanol is increasing exposure to low levels of methanol vapors in the environment and more specifically in occupational settings such as gas stations. Pump operators are exposed to relatively high levels of fuel vapors, the consequences of which have not been fully examined. In this study, the micronucleus assay in squamous oral cells was performed on pump operators of 28 gas stations in three different periods in the city of São Paulo, Brazil. The frequency of micronuclei (MN) was evaluated before and 1 year after a mixed fuel called MEG, which contains 33% methanol, 60% ethanol and 7% gasoline, was introduced. The third evaluation, 3 years later, represents a period where the number of cars using alcohol fuel had decreased drastically and the pump operator exposure to MEG became very low. The frequency of MN observed in 76 employees in 1992 (mean = 3.62 +/- 0.39) was significantly increased (P < 0.001) as compared with 76 operators exposed in 1989 (mean = 1.41 +/- 0.26) and 129 exposed in 1995 (mean = 1.20 +/- 0.15). These differences were also significant when compared with control groups not exposed professionally to motor fuel. These findings could indicate a mutagenic hazard of the MEG occurring in those with occupational exposure.

  10. Approaches for derivation of environmental quality criteria for substances applied in risk assessment of discharges from offshore drilling operations.

    PubMed

    Altin, Dag; Frost, Tone Karin; Nilssen, Ingunn

    2008-04-01

    In order to achieve the offshore petroleum industries "zero harm" goal to the environment, the environmental impact factor for drilling discharges was developed as a tool to identify and quantify the environmental risks associated with disposal of drilling discharges to the marine environment. As an initial step in this work the main categories of substances associated with drilling discharges and assumed to contribute to toxic or nontoxic stress were identified and evaluated for inclusion in the risk assessment. The selection were based on the known toxicological properties of the substances, or the total amount discharged together with their potential for accumulation in the water column or sediments to levels that could be expected to cause toxic or nontoxic stress to the biota. Based on these criteria 3 categories of chemicals were identified for risk assessment the water column and sediments: Natural organic substances, metals, and drilling fluid chemicals. Several approaches for deriving the environmentally safe threshold concentrations as predicted no effect concentrations were evaluated in the process. For the water column consensus were reached for using the species sensitivity distribution approach for metals and the assessment factor approach for natural organic substances and added drilling chemicals. For the sediments the equilibrium partitioning approach was selected for all three categories of chemicals. The theoretically derived sediment quality criteria were compared to field-derived threshold effect values based on statistical approaches applied on sediment monitoring data from the Norwegian Continental Shelf. The basis for derivation of predicted no effect concentration values for drilling discharges should be consistent with the principles of environmental risk assessment as described in the Technical Guidance Document on Risk Assessment issued by the European Union.

  11. Ion mobility spectrometric analysis of vaporous chemical warfare agents by the instrument with corona discharge ionization ammonia dopant ambient temperature operation.

    PubMed

    Satoh, Takafumi; Kishi, Shintaro; Nagashima, Hisayuki; Tachikawa, Masumi; Kanamori-Kataoka, Mieko; Nakagawa, Takao; Kitagawa, Nobuyoshi; Tokita, Kenichi; Yamamoto, Soichiro; Seto, Yasuo

    2015-03-20

    The ion mobility behavior of nineteen chemical warfare agents (7 nerve gases, 5 blister agents, 2 lachrymators, 2 blood agents, 3 choking agents) and related compounds including simulants (8 agents) and organic solvents (39) was comparably investigated by the ion mobility spectrometry instrument utilizing weak electric field linear drift tube with corona discharge ionization, ammonia doping, purified inner air drift flow circulation operated at ambient temperature and pressure. Three alkyl methylphosphonofluoridates, tabun, and four organophosphorus simulants gave the intense characteristic positive monomer-derived ion peaks and small dimer-derived ion peaks, and the later ion peaks were increased with the vapor concentrations. VX, RVX and tabun gave both characteristic positive monomer-derived ions and degradation product ions. Nitrogen mustards gave the intense characteristic positive ion peaks, and in addition distinctive negative ion peak appeared from HN3. Mustard gas, lewisite 1, o-chlorobenzylidenemalononitrile and 2-mercaptoethanol gave the characteristic negative ion peaks. Methylphosphonyl difluoride, 2-chloroacetophenone and 1,4-thioxane gave the characteristic ion peaks both in the positive and negative ion mode. 2-Chloroethylethylsulfide and allylisothiocyanate gave weak ion peaks. The marker ion peaks derived from two blood agents and three choking agents were very close to the reactant ion peak in negative ion mode and the respective reduced ion mobility was fluctuated. The reduced ion mobility of the CWA monomer-derived peaks were positively correlated with molecular masses among structurally similar agents such as G-type nerve gases and organophosphorus simulants; V-type nerve gases and nitrogen mustards. The slope values of the calibration plots of the peak heights of the characteristic marker ions versus the vapor concentrations are related to the detection sensitivity, and within chemical warfare agents examined the slope values for sarin, soman

  12. LASER PHYSICS: Formation of XeCl excimer molecules as a result of mixing of gas streams excited by a continuous discharge

    NASA Astrophysics Data System (ADS)

    Mikhkel'soo, V. T.; Treshchalov, A. B.; Peét, V. É.; Yalviste, É. Kh; Belokon', A. A.; Braĭnin, B. I.; Khritov, K. M.

    1987-07-01

    A longitudinal continuous discharge in two independent supersonic gas streams, which were subsequently mixed, was used for nonequilibrium electronic excitation of components undergoing reactions and emitting chemiluminescence. Formation of XeCl excimer molecules as a result of mixing of excited He:Xe = 95:5 and He:HCl(Cl2) = 99:1 streams was deduced from the XeCl* fluorescence spectra (B→X and C→A bands). The steady-state concentration of the XeCl molecules in B and C states determined in the mixing region was ~1010 cm-3 when the pump power was 50 W, so that the efficiency of conversion of the input electrical energy into the excimer fluorescence was ~1%.

  13. Ground gamma-ray survey of the Solforata gas discharge area, Alban Hills-Italy: a comparison between field and laboratory measurements.

    PubMed

    Di Paolo, Federico; Plastino, Wolfango; Povinec, Pavel P; Bella, Francesco; Budano, Antonio; De Vincenzi, Mario; Laubenstein, Matthias; Ruggieri, Federico

    2013-01-01

    Measurements of environmental radioactivity by HPGe gamma-spectrometry were carried out with the aim of investigating the distribution of natural radionuclides in a volcanic area and to compare two different methodologies - an in situ gamma-survey of the area and high accuracy laboratory measurements of soil samples. Results demonstrate good performance of the in situ technique, also confirmed by a correlation analysis between the results obtained by the two methodologies. A volcanic gas discharge area was chosen as the test site for the presence of natural long-lived radionuclides such as (40)K and (238)U, (235)U and (232)Th, and their decay chain members. Clear evidence of (222)Rn degassing in the area was confirmed by (226)Ra values measured by the in situ technique. Higher (40)K values measured by the in situ technique may be attributed to the presence of vegetation in the study area. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. The Ability of Microbial Community of Lake Baikal Bottom Sediments Associated with Gas Discharge to Carry Out the Transformation of Organic Matter under Thermobaric Conditions.

    PubMed

    Bukin, Sergei V; Pavlova, Olga N; Manakov, Andrei Y; Kostyreva, Elena A; Chernitsyna, Svetlana M; Mamaeva, Elena V; Pogodaeva, Tatyana V; Zemskaya, Tamara I

    2016-01-01

    The ability to compare the composition and metabolic potential of microbial communities inhabiting the subsurface sediment in geographically distinct locations is one of the keys to understanding the evolution and function of the subsurface biosphere. Prospective areas for study of the subsurface biosphere are the sites of hydrocarbon discharges on the bottom of the Lake Baikal rift, where ascending fluxes of gas-saturated fluids and oil from deep layers of bottom sediments seep into near-surface sediment. The samples of surface sediments collected in the area of the Posolskaya Bank methane seep were cultured for 17 months under thermobaric conditions (80°C, 5 MPa) with the addition of complementary organic substrate, and a different composition for the gas phase. After incubation, the presence of intact cells of microorganisms, organic matter transformation and the formation of oil biomarkers was confirmed in the samples, with the addition of Baikal diatom alga Synedra acus detritus, and gas mixture CH4:H2:CO2. Taxonomic assignment of the 16S rRNA sequence data indicates that the predominant sequences in the enrichment were Sphingomonas (55.3%), Solirubrobacter (27.5%) and Arthrobacter (16.6%). At the same time, in heat-killed sediment and in sediment without any additional substrates, which were cultivated in a CH4 atmosphere, no geochemical changes were detected, nor the presence of intact cells and 16S rRNA sequences of Bacteria and Archaea. This data may suggest that the decomposition of organic matter under culturing conditions could be performed by microorganisms from low-temperature sediment layers. One possible explanation of this phenomenon is migration of the representatives of the deep thermophilic community through fault zones in the near surface sediment layers, together with gas-bearing fluids.

  15. The Ability of Microbial Community of Lake Baikal Bottom Sediments Associated with Gas Discharge to Carry Out the Transformation of Organic Matter under Thermobaric Conditions

    PubMed Central

    Bukin, Sergei V.; Pavlova, Olga N.; Manakov, Andrei Y.; Kostyreva, Elena A.; Chernitsyna, Svetlana M.; Mamaeva, Elena V.; Pogodaeva, Tatyana V.; Zemskaya, Tamara I.

    2016-01-01

    The ability to compare the composition and metabolic potential of microbial communities inhabiting the subsurface sediment in geographically distinct locations is one of the keys to understanding the evolution and function of the subsurface biosphere. Prospective areas for study of the subsurface biosphere are the sites of hydrocarbon discharges on the bottom of the Lake Baikal rift, where ascending fluxes of gas-saturated fluids and oil from deep layers of bottom sediments seep into near-surface sediment. The samples of surface sediments collected in the area of the Posolskaya Bank methane seep were cultured for 17 months under thermobaric conditions (80°C, 5 MPa) with the addition of complementary organic substrate, and a different composition for the gas phase. After incubation, the presence of intact cells of microorganisms, organic matter transformation and the formation of oil biomarkers was confirmed in the samples, with the addition of Baikal diatom alga Synedra acus detritus, and gas mixture CH4:H2:CO2. Taxonomic assignment of the 16S rRNA sequence data indicates that the predominant sequences in the enrichment were Sphingomonas (55.3%), Solirubrobacter (27.5%) and Arthrobacter (16.6%). At the same time, in heat-killed sediment and in sediment without any additional substrates, which were cultivated in a CH4 atmosphere, no geochemical changes were detected, nor the presence of intact cells and 16S rRNA sequences of Bacteria and Archaea. This data may suggest that the decomposition of organic matter under culturing conditions could be performed by microorganisms from low-temperature sediment layers. One possible explanation of this phenomenon is migration of the representatives of the deep thermophilic community through fault zones in the near surface sediment layers, together with gas-bearing fluids. PMID:27242716

  16. Discharges of produced waters from oil and gas extraction via wastewater treatment plants are sources of disinfection by-products to receiving streams

    USGS Publications Warehouse

    Hladik, Michelle; Focazio, Michael J.; Engle, Mark

    2014-01-01

    Fluids co-produced with oil and gas production (produced waters) are often brines that contain elevated concentrations of bromide. Bromide is an important precursor of several toxic disinfection by-products (DBPs) and the treatment of produced water may lead to more brominated DBPs. To determine if wastewater treatment plants that accept produced waters discharge greater amounts of brominated DBPs, water samples were collected in Pennsylvania from four sites along a large river including an upstream site, a site below a publicly owned wastewater treatment plant (POTW) outfall (does not accept produced water), a site below an oil and gas commercial wastewater treatment plant (CWT) outfall, and downstream of the POTW and CWT. Of 29 DBPs analyzed, the site at the POTW outfall had the highest number detected (six) ranging in concentration from 0.01 to 0.09 μg L− 1 with a similar mixture of DBPs that have been detected at POTW outfalls elsewhere in the United States. The DBP profile at the CWT outfall was much different, although only two DBPs, dibromochloronitromethane (DBCNM) and chloroform, were detected, DBCNM was found at relatively high concentrations (up to 8.5 μg L− 1). The water at the CWT outfall also had a mixture of inorganic and organic precursors including elevated concentrations of bromide (75 mg L− 1) and other organic DBP precursors (phenol at 15 μg L− 1). To corroborate these DBP results, samples were collected in Pennsylvania from additional POTW and CWT outfalls that accept produced waters. The additional CWT also had high concentrations of DBCNM (3.1 μg L− 1) while the POTWs that accept produced waters had elevated numbers (up to 15) and concentrations of DBPs, especially brominated and iodinated THMs (up to 12 μg L− 1 total THM concentration). Therefore, produced water brines that have been disinfected are potential sources of DBPs along with DBP precursors to streams wherever these wastewaters are discharged.

  17. Emissions from a vehicle fitted to operate on either petrol or compressed natural gas.

    PubMed

    Ristovski, Z; Morawska, L; Ayoko, G A; Johnson, G; Gilbert, D; Greenaway, C

    2004-05-05

    The purpose of this work was to evaluate the physical and chemical properties of emission products from a six-cylinder sedan car under a variety of operating conditions, before and after it has been converted to compressed natural gas (CNG) fuel. The specific focus of the measurements was on emission levels and characteristics of ultra fine particles and the emission levels together with the emissions of gaseous pollutants for a range of operating conditions before and up to 3 months after the vehicle was converted are presented and discussed in the paper. The investigations showed that converting a petrol operating vehicle to CNG has the potential of reducing some of the emissions and thus risks, while it does not appear to have an impact on others. In particular there was no statistically significant change in the emission of particles for the vehicle operating on petrol, before the conversion, compared to the emissions for the vehicle operating on CNG, after the conversion. There was a significant lowering of emissions of total polycyclic aromatic hydrocarbons and formaldehyde when the vehicle was operated on CNG, and a reduction of global warming potential was also observed when the vehicle was run on CNG, but the later gain is only at high vehicle speeds/loads, and would thus have to be considered in view of traffic and transport models for the region (in these models vehicle speed is an important parameter).

  18. XeCl Avalanche discharge laser employing Ar as a diluent

    DOEpatents

    Sze, Robert C.

    1981-01-01

    A XeCl avalanche discharge exciplex laser which uses a gaseous lasing starting mixture of: (0.2%-0.4% chlorine donor/2.5%-10% Xe/97.3%-89.6% Ar). The chlorine donor normally comprises HCl but can also comprise CCl.sub.4 BCl.sub.3. Use of Ar as a diluent gas reduces operating pressures over other rare gas halide lasers to near atmospheric pressure, increases output lasing power of the XeCl avalanche discharge laser by 30% to exceed KrF avalanche discharge lasing outputs, and is less expensive to operate.

  19. XeCl avalanche discharge laser employing Ar as a diluent

    DOEpatents

    Sze, R.C.

    1979-10-10

    A XeCl avalanche discharge exciplex laser which uses a gaseous lasing starting mixture of: 0.2 to 0.4% chlorine donor/2.5% to 10% Xe/97.3% to 89.6% Ar) is provided. The chlorine donor normally comprises HCl but can also comprise CCl/sub 4/ BCl/sub 3/. Use of Ar as a diluent gas reduces operating pressures over other rare gas halide lasers to near atmospheric pressure, increases output lasing power of the XeCl avalanche discharge laser by 30% to exceed KrF avalanche discharge lasing outputs, and is less expensive to operate.

  20. Lung surgery - discharge

    MedlinePlus

    Thoracotomy - discharge; Lung tissue removal - discharge; Pneumonectomy - discharge; Lobectomy - discharge; Lung biopsy - discharge; Thoracoscopy - discharge; Video-assisted thoracoscopic surgery - discharge; VATS - ...

  1. Determination of gas-phase emitter effect in ac operated ceramic metal halide lamps

    NASA Astrophysics Data System (ADS)

    Westermeier, Michael; Langenscheidt, Oliver; Reinelt, Jens; Mentel, Juergen; Awakowicz, Peter

    2007-10-01

    Dy-densities and the corresponding electrode tip temperature have been determined by spatially and temporally resolved spectroscopy at and in front of electrodes operated with an ac-current in metal halide lamps. The lamps, made of transparent YAG arc tubes and containing Hg+NaTlDy iodides, were installed in the Bochum model lamp as an outer sleeve. It allows salt pressure depending measurements of the electrode temperature profiles, yielding a global tip temperature and an electrode loss power, and spectroscopic measurements of absolute line intensities to determine the Dy-densities in front of the electrode. It is found that Dy atoms in the gas phase generate a strong gas-phase emitter effect characterized by a clear reduction of the work function. It reduces the electrode temperature, the input power and influences the type of arc attachment. To distinguish between cathodic and anodic effects, phase resolved measurements of the electrode tip temperature will be presented.

  2. Current distribution measurements inside an electromagnetic plasma gun operated in a gas-puff mode

    PubMed Central

    Poehlmann, Flavio R.; Cappelli, Mark A.; Rieker, Gregory B.

    2010-01-01

    Measurements are presented of the time-dependent current distribution inside a coaxial electromagnetic plasma gun. The measurements are carried out using an array of six axially distributed dual-Rogowski coils in a balanced circuit configuration. The radial current distributions indicate that operation in the gas-puff mode, i.e., the mode in which the electrode voltage is applied before injection of the gas, results in a stationary ionization front consistent with the presence of a plasma deflagration. The effects of varying the bank capacitance, transmission line inductance, and applied electrode voltage were studied over the range from 14 to 112 μF, 50 to 200 nH, and 1 to 3 kV, respectively. PMID:21267082

  3. Current distribution measurements inside an electromagnetic plasma gun operated in a gas-puff mode.

    PubMed

    Poehlmann, Flavio R; Cappelli, Mark A; Rieker, Gregory B

    2010-12-01

    Measurements are presented of the time-dependent current distribution inside a coaxial electromagnetic plasma gun. The measurements are carried out using an array of six axially distributed dual-Rogowski coils in a balanced circuit configuration. The radial current distributions indicate that operation in the gas-puff mode, i.e., the mode in which the electrode voltage is applied before injection of the gas, results in a stationary ionization front consistent with the presence of a plasma deflagration. The effects of varying the bank capacitance, transmission line inductance, and applied electrode voltage were studied over the range from 14 to 112 μF, 50 to 200 nH, and 1 to 3 kV, respectively.

  4. ICU Admission, Discharge, and Triage Guidelines: A Framework to Enhance Clinical Operations, Development of Institutional Policies, and Further Research.

    PubMed

    Nates, Joseph L; Nunnally, Mark; Kleinpell, Ruth; Blosser, Sandralee; Goldner, Jonathan; Birriel, Barbara; Fowler, Clara S; Byrum, Diane; Miles, William Scherer; Bailey, Heatherlee; Sprung, Charles L

    2016-08-01

    To update the Society of Critical Care Medicine's guidelines for ICU admission, discharge, and triage, providing a framework for clinical practice, the development of institutional policies, and further research. An appointed Task Force followed a standard, systematic, and evidence-based approach in reviewing the literature to develop these guidelines. The assessment of the evidence and recommendations was based on the principles of the Grading of Recommendations Assessment, Development and Evaluation system. The general subject was addressed in sections: admission criteria and benefits of different levels of care, triage, discharge timing and strategies, use of outreach programs to supplement ICU care, quality assurance/improvement and metrics, nonbeneficial treatment in the ICU, and rationing considerations. The literature searches yielded 2,404 articles published from January 1998 to October 2013 for review. Following the appraisal of the literature, discussion, and consensus, recommendations were written. Although these are administrative guidelines, the subjects addressed encompass complex ethical and medico-legal aspects of patient care that affect daily clinical practice. A limited amount of high-quality evidence made it difficult to answer all the questions asked related to ICU admission, discharge, and triage. Despite these limitations, the members of the Task Force believe that these recommendations provide a comprehensive framework to guide practitioners in making informed decisions during the admission, discharge, and triage process as well as in resolving issues of nonbeneficial treatment and rationing. We need to further develop preventive strategies to reduce the burden of critical illness, educate our noncritical care colleagues about these interventions, and improve our outreach, developing early identification and intervention systems.

  5. High pressure operation of tubular solid oxide fuel cells and their intergration with gas turbines

    SciTech Connect

    Haynes, C.; Wepfer, W.J.

    1996-12-31

    Fossil fuels continue to be used at a rate greater than that of their natural formation, and the current byproducts from their use are believed to have a detrimental effect on the environment (e.g. global warming). There is thus a significant impetus to have cleaner, more efficient fuel consumption alternatives. Recent progress has led to renewed vigor in the development of fuel cell technology, which has been shown to be capable of producing high efficiencies with relatively benign exhaust products. The tubular solid oxide fuel cell developed by Westinghouse Electric Corporation has shown significant promise. Modeling efforts have been and are underway to optimize and better understand this fuel cell technology. Thus far, the bulk of modeling efforts has been for operation at atmospheric pressure. There is now interest in developing high-efficiency integrated gas turbine/solid oxide fuel cell systems. Such operation of fuel cells would obviously occur at higher pressures. The fuel cells have been successfully modeled under high pressure operation and further investigated as integrated components of an open loop gas turbine cycle.

  6. Greenhouse gas emissions from building and operating electric power plants in the Upper Colorado River Basin.

    PubMed

    Pacca, Sergio; Horvath, Arpad

    2002-07-15

    As demand for electricity increases, investments into new generation capacity from renewable and nonrenewable sources should include assessment of global (climate) change consequences not just of the operational phase of the power plants but construction effects as well. In this paper, the global warming effect (GWE) associated with construction and operation of comparable hydroelectric, wind, solar, coal, and natural gas power plants is estimated for four time periods after construction. The assessment includes greenhouse gas emissions from construction, burning of fuels, flooded biomass decay in the reservoir, loss of net ecosystem production, and land use. The results indicate that a wind farm and a hydroelectric plant in an arid zone (such as the Glen Canyon in the Upper Colorado River Basin) appear to have lower GWE than other power plants. For the Glen Canyon hydroelectric plant, the upgrade 20 yr after the beginning of operation increased power capacity by 39% but resulted in a mere 1% of the CO2 emissions from the initial construction and came with no additional emissions from the reservoir, which accounts for the majority of the GWE.

  7. Selection of the most advantageous gas turbine air filtration system: Comparative study of actual operating experience

    SciTech Connect

    Gilani, S.I.; Mehr, M.Z.

    1985-01-01

    This paper discusses relative merits of three types of air filtration systems used by Sui Northern Gas Pipelines Ltd. (Pakistan), on its gas turbine compressor packages. These Filtration systems are: (i) Two stage inertial plus auto oil bath type multi-duty filters by AAF used on Saturn Mark-1 packages manufactured by Solar Turbines Inc. (ii) Three stage high efficiency barrier filters by AAF used on Centaur packages by Solar. (iii) Single stage pulse-jet self-cleaning filter by Donaldson again used on a Centaur package. The selection is primarily based in package performance data collected over a 15 month period analyzing power lossmore » due to fouling effects and related operation and maintenance costs for the three systems. The Company's operating experience indicates that on new installations the pulse clean system offers the best advantage both in terms of filtration costs as well as availability of additional horse power when operating under moderate to severe environmental conditions.« less

  8. Investigation of gas generation in regenerative fuel cells by low-energy X-rays

    NASA Astrophysics Data System (ADS)

    Selamet, Omer Faruk; Deevanhxay, Phengxay; Tsushima, Shohji; Hirai, Shuichiro

    2015-11-01

    Gas generation and discharge behaviors in an operating regenerative fuel cell (RFC) are investigated using low-energy X-ray radiography. In situ visualization at high spatial and temporal resolution reveal dynamic and inhomogeneous behaviors of the gas generation in the membrane electrode assembly (MEA) in the RFC. Temporal and spatial variation of the gas thickness in the MEA is quantitatively discussed and shows an intermittent and periodic discharge processes of the gas generated by electrolysis, suggesting that the reaction sites in the catalyst layer and the discharging path of gas bubbles are well established in the MEA for the electrolysis. Larger gas accumulation and discharge in the gas diffusion layer (GDL) under the ribs are identified in comparison with those under the channels, which is attributed to the relatively longer path for accumulated gas under the ribs to be discharged into the flow channels.

  9. Gas

    MedlinePlus

    ... swallow and the breakdown of undigested food by bacteria in the large intestine. Certain foods may cause gas. Foods that produce gas in one person may not cause gas in another. You can reduce the amount of gas you have by Drinking lots of water and non-fizzy drinks Eating more slowly so ...

  10. Emissions from oil and gas operations in the United States and their air quality implications.

    PubMed

    Allen, David T

    2016-06-01

    The energy supply infrastructure in the United States has been changing dramatically over the past decade. Increased production of oil and natural gas, particularly from shale resources using horizontal drilling and hydraulic fracturing, made the United States the world's largest producer of oil and natural gas in 2014. This review examines air quality impacts, specifically, changes in greenhouse gas, criteria air pollutant, and air toxics emissions from oil and gas production activities that are a result of these changes in energy supplies and use. National emission inventories indicate that volatile organic compound (VOC) and nitrogen oxide (NOx) emissions from oil and gas supply chains in the United States have been increasing significantly, whereas emission inventories for greenhouse gases have seen slight declines over the past decade. These emission inventories are based on counts of equipment and operational activities (activity factors), multiplied by average emission factors, and therefore are subject to uncertainties in these factors. Although uncertainties associated with activity data and missing emission source types can be significant, multiple recent measurement studies indicate that the greatest uncertainties are associated with emission factors. In many source categories, small groups of devices or sites, referred to as super-emitters, contribute a large fraction of emissions. When super-emitters are accounted for, multiple measurement approaches, at multiple scales, produce similar results for estimated emissions. Challenges moving forward include identifying super-emitters and reducing their emission magnitudes. Work done to date suggests that both equipment malfunction and operational practices can be important. Finally, although most of this review focuses on emissions from energy supply infrastructures, the regional air quality implications of some coupled energy production and use scenarios are examined. These case studies suggest that both

  11. Evidence of emissions from oil and gas drilling operations in northeastern Colorado

    NASA Astrophysics Data System (ADS)

    Petron, G.; Montzka, S. A.; Karion, A.; Miller, B. R.; Frost, G. J.; Hirsch, A.; Sweeney, C.; Andrews, A. E.; Dlugokencky, E. J.; Hall, B. D.; Trainer, M.; Welsh, D. C.; Wolfe, D. E.; Tans, P. P.

    2010-12-01

    Since 2007, air samples collected regularly at NOAA tall towers and from aircraft across the US have been analyzed for over sixty different species, including greenhouse gases (CO2, CH4, N2O, SF6), CO, several hydrocarbons (propane, n-butane, pentanes, benzene, acetylene), and ozone-depleting substances. The Boulder Atmospheric Observatory (BAO) is a 300-m tall tower located 35 km north of the Denver metropolitan area in the northern Colorado Front Range. The BAO sits on the southwestern edge of the Denver-Julesburg Basin (DJB), home to over 15,000 oil and gas wells. Using in-situ meteorological data, we analyze the air composition of the BAO samples for three different wind sectors: the North and East sector (with strong contributions from oil and gas production operations and cattle feedlots), the South sector (dominated by the Denver urban area), and the West sector (containing the foothills of the Rocky Mountains and a few oil and gas wells). Air samples from the BAO North and East sector exhibit enhanced levels of alkanes that are strongly correlated with each other. To put these BAO samples in a regional context, we drove a mobile laboratory around BAO during the summer of 2008. A continuous methane analyzer was used to detect regional enhancements in methane and local plumes from point sources (including a natural gas processing plant, feedlot, and waste water treatment plant). Targeted air samples within and outside of plumes were collected and later analyzed in the NOAA lab. Samples collected over the DJB show very similar molar ratios of alkanes as the BAO samples from the North and East sector. These alkane ratios compare very well with the ratios measured in over 70 natural gas samples collected at various wells in the DJB in 2006.

  12. Modeling and experiments on differential pumping in linear plasma generators operating at high gas flows

    NASA Astrophysics Data System (ADS)

    van Eck, H. J. N.; Koppers, W. R.; van Rooij, G. J.; Goedheer, W. J.; Engeln, R.; Schram, D. C.; Cardozo, N. J. Lopes; Kleyn, A. W.

    2009-03-01

    The direct simulation Monte Carlo (DSMC) method was used to investigate the efficiency of differential pumping in linear plasma generators operating at high gas flows. Skimmers are used to separate the neutrals from the plasma beam, which is guided from the source to the target by a strong axial magnetic field. In this way, the neutrals are prevented to reach the target region. The neutral flux to the target must be lower than the plasma flux to enable ITER relevant plasma-surface interaction (PSI) studies. It is therefore essential to control the neutral gas dynamics. The DSMC method was used to model the expansion of a hot gas in a low pressure vessel where a small discrepancy in shock position was found between the simulations and a well-established empirical formula. Two stage differential pumping was modeled and applied in the linear plasma devices Pilot-PSI and PLEXIS. In Pilot-PSI a factor of 4.5 pressure reduction for H2 has been demonstrated. Both simulations and experiments showed that the optimum skimmer position depends on the position of the shock and therefore shifts for different gas parameters. The shape of the skimmer has to be designed such that it has a minimum impact on the shock structure. A too large angle between the skimmer and the forward direction of the gas flow leads to an influence on the expansion structure. A pressure increase in front of the skimmer is formed and the flow of the plasma beam becomes obstructed. It has been shown that a skimmer with an angle around 53° gives the best performance. The use of skimmers is implemented in the design of the large linear plasma generator Magnum-PSI. Here, a three stage differentially pumped vacuum system is used to reach low enough neutral pressures near the target, opening a door to PSI research in the ITER relevant regime.

  13. Gas phase carbonyl compounds in ship emissions: Differences between diesel fuel and heavy fuel oil operation

    NASA Astrophysics Data System (ADS)

    Reda, Ahmed A.; Schnelle-Kreis, J.; Orasche, J.; Abbaszade, G.; Lintelmann, J.; Arteaga-Salas, J. M.; Stengel, B.; Rabe, R.; Harndorf, H.; Sippula, O.; Streibel, T.; Zimmermann, R.

    2014-09-01

    Gas phase emission samples of carbonyl compounds (CCs) were collected from a research ship diesel engine at Rostock University, Germany. The ship engine was operated using two different types of fuels, heavy fuel oil (HFO) and diesel fuel (DF). Sampling of CCs was performed from diluted exhaust using cartridges and impingers. Both sampling methods involved the derivatization of CCs with 2,4-Dinitrophenylhydrazine (DNPH). The CCs-hydrazone derivatives were analyzed by two analytical techniques: High Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD) and Gas Chromatography-Selective Ion Monitoring-Mass Spectrometry (GC-SIM-MS). Analysis of DNPH cartridges by GC-SIM-MS method has resulted in the identification of 19 CCs in both fuel operations. These CCs include ten aliphatic aldehydes (formaldehyde, acetaldehyde, propanal, isobutanal, butanal, isopentanal, pentanal, hexanal, octanal, nonanal), three unsaturated aldehydes (acrolein, methacrolein, crotonaldehyde), three aromatic aldehyde (benzaldehyde, p-tolualdehyde, m,o-molualdehyde), two ketones (acetone, butanone) and one heterocyclic aldehyde (furfural). In general, all CCs under investigation were detected with higher emission factors in HFO than DF. The total carbonyl emission factor was determined and found to be 6050 and 2300 μg MJ-1 for the operation with HFO and DF respectively. Formaldehyde and acetaldehyde were found to be the dominant carbonyls in the gas phase of ship engine emission. Formaldehyde emissions factor varied from 3500 μg MJ-1 in HFO operation to 1540 μg MJ-1 in DF operation, which is 4-30 times higher than those of other carbonyls. Emission profile contribution of CCs showed also a different pattern between HFO and DF operation. The contribution of formaldehyde was found to be 58% of the emission profile of HFO and about 67% of the emission profile of DF. Acetaldehyde showed opposite behavior with higher contribution of 16% in HFO compared to 11% for DF. Heavier carbonyls

  14. Gas discharge plasma treatment of poly(ethylene glycol-co-1,3/1,4 cyclohexanedimethanol terephthalate) for enhanced paint adhesion

    SciTech Connect

    Salapare, Hernando S.; Cosiñero, Hannah Shamina O.; Suarez, Beverly Anne T.; Bacaoco, Miguel Y.; Ramos, Henry J.; Nuñez, Julius Andrew P.; Guittard, Frédéric

    2016-07-15

    Low-energy hydrogen-ions and tetrafluoromethane-ions produced from a gas discharge ion source were irradiated to poly(ethylene glycol-co-1,3/1,4 cyclohexanedimethanol terephthalate) (PETG) sheets for enhancing paint adhesion. The ion beams were characterized using a cast steel mass spectrometer, while the untreated and treated samples were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, contact angle measurements, and profilometry. The paint adhesion was determined by using the standard method for evaluating adhesion by knife [ASTM D6677-07, Standard Test Method for Evaluating Adhesion by Knife (ASTM International, West Conshohocken, PA, 2012)] and was correlated with the calculation of the work of adhesion derived from the Young–Dupré equation. After plasma treatment, a significant decrease in the contact angle was observed in all samples, except for the CF{sub 4} ion-treated samples with the discharge current of 3 mA and an irradiation time of 30 min. At longer irradiation times, the treated samples showed lesser changes in the contact angle measurement. The increase in the average and root-mean-square surface roughness was observed on the samples after plasma treatment. The samples treated with either H{sub 2} or CF{sub 4} ions for 15 min showed a direct correlation between the discharge current and surface roughness. The samples treated for 30 min showed no significant correlation between the surface roughness and discharge current, which can be attributed to the possible melting of the samples since PETG has a low melting point. The observation made in this study on the relationship of wettability and surface roughness is consistent with the Wenzel wetting mode. Scanning electron micrographs showed surface etching on the hydrogen ion-treated samples while no significant surface changes were observed for the CF{sub 4} ion-treated samples. In general, paint adhesion was stronger for samples that exhibited

  15. Gas discharge plasma treatment of poly(ethylene glycol-co-1,3/1,4 cyclohexanedimethanol terephthalate) for enhanced paint adhesion

    SciTech Connect

    Salapare, Hernando S., E-mail: hssalapare@up.edu.ph; Department of Physical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Manila, Manila City 1000; College of Science, Pamantasan ng Lungsod ng Maynila, Intramuros, Manila City 1002

    2016-07-15

    Low-energy hydrogen-ions and tetrafluoromethane-ions produced from a gas discharge ion source were irradiated to poly(ethylene glycol-co-1,3/1,4 cyclohexanedimethanol terephthalate) (PETG) sheets for enhancing paint adhesion. The ion beams were characterized using a cast steel mass spectrometer, while the untreated and treated samples were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, contact angle measurements, and profilometry. The paint adhesion was determined by using the standard method for evaluating adhesion by knife [ASTM D6677-07, Standard Test Method for Evaluating Adhesion by Knife (ASTM International, West Conshohocken, PA, 2012)] and was correlated with the calculation of the work of adhesion derived frommore » the Young–Dupré equation. After plasma treatment, a significant decrease in the contact angle was observed in all samples, except for the CF{sub 4} ion-treated samples with the discharge current of 3 mA and an irradiation time of 30 min. At longer irradiation times, the treated samples showed lesser changes in the contact angle measurement. The increase in the average and root-mean-square surface roughness was observed on the samples after plasma treatment. The samples treated with either H{sub 2} or CF{sub 4} ions for 15 min showed a direct correlation between the discharge current and surface roughness. The samples treated for 30 min showed no significant correlation between the surface roughness and discharge current, which can be attributed to the possible melting of the samples since PETG has a low melting point. The observation made in this study on the relationship of wettability and surface roughness is consistent with the Wenzel wetting mode. Scanning electron micrographs showed surface etching on the hydrogen ion-treated samples while no significant surface changes were observed for the CF{sub 4} ion-treated samples. In general, paint adhesion was stronger for samples that

  16. Computer simulation of nonstationary thermal fields in design and operation of northern oil and gas fields

    SciTech Connect

    Vaganova, N. A., E-mail: vna@imm.uran.ru; Filimonov, M. Yu., E-mail: fmy@imm.uran.ru

    2015-11-30

    A mathematical model, numerical algorithm and program code for simulation and long-term forecasting of changes in permafrost as a result of operation of a multiple well pad of northern oil and gas field are presented. In the model the most significant climatic and physical factors are taken into account such as solar radiation, determined by specific geographical location, heterogeneous structure of frozen soil, thermal stabilization of soil, possible insulation of the objects, seasonal fluctuations in air temperature, and freezing and thawing of the upper soil layer. Results of computing are presented.

  17. 78 FR 72096 - Environmental Documents Prepared for Oil, Gas, and Mineral Operations by the Gulf of Mexico Outer...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-02

    ... by the Gulf of Mexico Outer Continental Shelf (OCS) Region AGENCY: Bureau of Ocean Energy Management... & Gas Corporation, Ewing Bank, Block 834, 9/27/2013 Development Operations Lease OCS- G27982...

  18. Detection and quantification of methane and VOC emissions from oil and gas production operations using remote measurements, Interim report

    EPA Science Inventory

    Improved understanding of air pollutant emissions from oil and gas production operations is needed. With a steadily increasing number of production sources, the impact of emitted volatile organic compounds (VOCs) on regional ozone is potentially significant. As the separation dis...

  19. Monte Carlo uncertainty analyses of a bLS inverse-dispersion technique for measuring gas emissions from livestock operations

    USDA-ARS?s Scientific Manuscript database

    The backward Lagrangian stochastic (bLS) inverse-dispersion technique has been used to measure fugitive gas emissions from livestock operations. The accuracy of the bLS technique, as indicated by the percentages of gas recovery in various tracer-release experiments, has generally been within ± 10% o...

  20. Determination of Aqueous Formic and Acetic Acids by Purge-and-Trap Analysis with a Needle-Type Extraction Device and Gas Chromatography Barrier Discharge Ionization Detector.

    PubMed

    Ueta, Ikuo; Nakamura, Yohei; Kawakubo, Susumu; Saito, Yoshihiro

    2018-01-01

    A purge-and-trap method using a needle-type extraction device and a gas chromatography-barrier discharge ionization detector for the analysis of formic (FA) and acetic acids (AA) in aqueous samples is presented. An activated carbon-based adsorbent, Carboxen 1000, was employed as the extraction medium for the needle-type extraction device. The sampling time was 5 min for collecting headspace gas in a glass vial, including 10 mL of an aqueous sample. The detection limits for FA and AA with a headspace sampling volume of 100 mL were 3.3 and 2.0 mg L -1 , respectively. Since the proposed method was based on purge-and-trap collection, it was suitable for the determination of aqueous FA and AA in complex matrices with simple and rapid sample preparation steps. The proposed method was applied to the determination of FA and AA in fruit juice samples and FA generated by the electrochemical reduction of carbon dioxide.