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Sample records for inert gas dilution

  1. Automated measurement of respiratory gas exchange by an inert gas dilution technique

    NASA Technical Reports Server (NTRS)

    Sawin, C. F.; Rummel, J. A.; Michel, E. L.

    1974-01-01

    A respiratory gas analyzer (RGA) has been developed wherein a mass spectrometer is the sole transducer required for measurement of respiratory gas exchange. The mass spectrometer maintains all signals in absolute phase relationships, precluding the need to synchronize flow and gas composition as required in other systems. The RGA system was evaluated by comparison with the Douglas bag technique. The RGA system established the feasibility of the inert gas dilution method for measuring breath-by-breath respiratory gas exchange. This breath-by-breath analytical capability permits detailed study of transient respiratory responses to exercise.

  2. Inert Gas Dilution Effect on the Flammability Limits of Hydrocarbon Mixtures 

    E-print Network

    Zhao, Fuman

    2012-02-14

    previous one from U.S. BMs???????....69 5.3 Ethane flammability properties with dilution of nitrogen (25 ?C and 1 atm)??????????????????????..????.. 70 5.4 Propane flammability properties with dilution of nitrogen (25 ?C and 1 atm...)???????????????????????..???.. 72 5.8 Flammability properties of methane and propane at different molar radios (20 %/80%, 40%/60%, 60%/40%, and 80%/20%) with dilution of nitrogen (25 ?C and 1 atm)?..????.?..?????????73 5.9 Flammability properties of ethane and propane...

  3. Inert gas thrusters

    NASA Technical Reports Server (NTRS)

    Kaufman, H. R.; Robinson, R. S.

    1979-01-01

    Inert gas thrusters considered for space propulsion systems were investigated. Electron diffusion across a magnetic field was examined utilizing a basic model. The production of doubly charged ions was correlated using only overall performance parameters. The use of this correlation is therefore possible in the design stage of large gas thrusters, where detailed plasma properties are not available. Argon hollow cathode performance was investigated over a range of emission currents, with the positions of the inert, keeper, and anode varied. A general trend observed was that the maximum ratio of emission to flow rate increased at higher propellant flow rates. It was also found that an enclosed keeper enhances maximum cathode emission at high flow rates. The maximum cathode emission at a given flow rate was associated with a noisy high voltage mode. Although this mode has some similarities to the plume mode found at low flows and emissions, it is encountered by being initially in the spot mode and increasing emission. A detailed analysis of large, inert-gas thruster performance was carried out. For maximum thruster efficiency, the optimum beam diameter increases from less than a meter at under 2000 sec specific impulse to several meters at 10,000 sec. The corresponding range in input power ranges from several kilowatts to megawatts.

  4. Inert gas ion thruster

    NASA Technical Reports Server (NTRS)

    Ramsey, W. D.

    1980-01-01

    Inert gas performance with three types of 12 cm diameter magnetoelectrostatic containment (MESC) ion thrusters was tested. The types tested included: (1) a hemispherical shaped discharge chamber with platinum cobalt magnets; (2) three different lengths of the hemispherical chambers with samarium cobalt magnets; and (3) three lengths of the conical shaped chambers with aluminum nickel cobalt magnets. The best argon performance was produced by a 8.0 cm long conical chamber with alnico magnets. The best xenon high mass utilization performance was obtained with the same 8.0 cm long conical thruster. The hemispherical thruster obtained 75 to 87% mass utilization at 185 to 205 eV/ion of singly charged ion equivalent beam.

  5. Inert gas thrusters

    NASA Technical Reports Server (NTRS)

    Kaufman, H. R.; Robinson, R. S.

    1980-01-01

    Some advances in component technology for inert gas thrusters are described. The maximum electron emission of a hollow cathode with Ar was increased 60-70% by the use of an enclosed keeper configuration. Operation with Ar, but without emissive oxide, was also obtained. A 30 cm thruster operated with Ar at moderate discharge voltages give double-ion measurements consistent with a double ion correlation developed previously using 15 cm thruster data. An attempt was made to reduce discharge losses by biasing anodes positive of the discharge plasma. The reason this attempt was unsuccessful is not yet clear. The performance of a single-grid ion-optics configuration was evaluated. The ion impingement on the single grid accelerator was found to approach the value expected from the projected blockage when the sheath thickness next to the accelerator was 2-3 times the aperture diameter.

  6. Inert gas thrusters

    NASA Technical Reports Server (NTRS)

    Kaufman, H. R.

    1978-01-01

    Inert gas thrusters have continued to be of interest for space propulsion applications. Xenon is of interest in that its physical characteristics are well suited to propulsion. High atomic weight and low tankage fraction were major factors in this choice. If a large amount of propellant was required, so that cryogenic storage was practical, argon is a more economical alternative. Argon was also the preferred propellant for ground applications of thruster technology, such as sputter etching and deposition. Additional magnetic field measurements are reported. These measurements should be of use in magnetic field design. The diffusion of electrons through the magnetic field above multipole anodes was studied in detail. The data were consistent with Bohm diffusion across a magnetic field. The theory based on Bohm diffusion was simple and easily used for diffusion calculations. Limited startup data were obtained for multipole discharge chambers. These data were obtained with refractory cathodes, but should be useful in predicting the upper limits for starting with hollow cathodes.

  7. Inert gas thrusters

    NASA Technical Reports Server (NTRS)

    Kaufman, H. R.

    1976-01-01

    Inert gases are of interest as possible alternatives to the usual electric thruster propellants of mercury and cesium. The multipole discharge chamber investigated was shown capable of low discharge chamber losses and flat ion beam profiles with a minimum of optimization. Minimum discharge losses were 200 to 250 eV/ion for xenon and 300 to 350 eV/ion for argon, while flatness parameters in the plane of the accelerator grid were 0.85 to 0.95. The design used employs low magnetic field strengths, which permits the use of sheet-metal parts. The corner problem of the discharge chamber was resolved with recessed corner anodes, which approximately equalized both the magnetic field above the anodes and the electron currents to these anodes. Argon hollow cathodes were investigated at currents up to about 5 amperes using internal thermionic emitters. Cathode chamber diameter optimized in the 1.0 to 2.5 cm range, while orifices diameter optimized in the 0.5 to 5 mm range. The use of a bias voltage for the internal emitter extended the operating range and facilitated starting. The masses of 15 and 30 cm flight type thrusters were estimated at about 4.2 and 10.8 kg.

  8. 33 CFR 154.824 - Inerting, enriching, and diluting systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... oxygen analyzers are used, the higher oxygen concentration reading controls the inerting or enriching... section. (f) Each oxygen or hydrocarbon analyzer required by this section must: (1) Be installed in... concentration continuously not more than 30 pipe diameters from the gas injection point. (g) Oxygen...

  9. 33 CFR 154.824 - Inerting, enriching, and diluting systems.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...CONTINUED) POLLUTION FACILITIES TRANSFERRING OIL OR HAZARDOUS...meters (32.8 ft.) from the facility vapor connection that ensures...produce the inert gas, have a hydraulic seal and non-return valve...in an enriching system at a facility that receives cargo...

  10. 33 CFR 154.824 - Inerting, enriching, and diluting systems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...CONTINUED) POLLUTION FACILITIES TRANSFERRING OIL OR HAZARDOUS...meters (32.8 ft.) from the facility vapor connection that ensures...produce the inert gas, have a hydraulic seal and non-return valve...in an enriching system at a facility that receives cargo...

  11. 33 CFR 154.824 - Inerting, enriching, and diluting systems.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...CONTINUED) POLLUTION FACILITIES TRANSFERRING OIL OR HAZARDOUS...meters (32.8 ft.) from the facility vapor connection that ensures...produce the inert gas, have a hydraulic seal and non-return valve...in an enriching system at a facility that receives cargo...

  12. Mechanisms of inert gas narcosis

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Experiments describing the mechanism of inert gas narcosis are reported. A strain of mice, genetically altered to increase susceptibility to botulin poisoning (synaptic response) appears to increase metabolic rates while breathing argon; this infers a genetically altered synaptic response to both botulin toxin and narcotic gases. Studies of metabolic depression in human subjects breathing either air or a 30% mixture of nitrous oxide indicate that nitrous oxide narcosis does not produce pronounced metabolic depression. Tests on mice for relative susceptibilities to narcosis and oxygen poisoning as a function of fatty membrane composition show that alteration of the fatty acid composition of phospholipids increases resistance to metabolically depressant effects of argon but bas no effect on nitrous oxide narcosis. Another study suggests that acclimatization to low tension prior to high pressure oxygen treatment enhances susceptibility of mice to convulsions and death; developing biochemical lesions cause CNS metabolite reductions and pulmonary damage.

  13. SP-100 inert gas act activation

    SciTech Connect

    Wilcox, A.D.

    1991-09-01

    As part of the SP-100 test program at the US Department of Energy Field Office, Richland, there are plans to test the SP-100 space reactor in a vacuum in the test facility shown in Figure 1. The vacuum vessel will be in an inert gas atmosphere in the reactor experiment (RX) cell. The upper assembly (UA)/pump cells will also be inerted. The objective is to determine whether the radioactivity levels in the facility exhaust are within permissible levels. This radioactivity comes from leakage of activation products from the inert gas cells into the facility ventilation exhaust stream. The specific activities were calculated for the activation products from the combinations of inert gases that were considered for this facility, for a range of leakage rates, and for leakage from the UA/pump cells into the RX cell, and results are detailed in this report.

  14. Fast, Nonspattering Inert-Gas Welding

    NASA Technical Reports Server (NTRS)

    Gilbert, Jeffrey L.

    1991-01-01

    Proposed welding technique combines best features of metal (other than tungsten)/inert-gas welding, plasma arc welding, and tungsten/inert-gas welding. Advantages include: wire fed to weld joint preheated, therefore fed at high speed without spattering; high-frequency energy does not have to be supplied to workpiece to initiate welding; size of arc gap not critical, power-supply control circuit adjusts voltage across gap to compensate for changes; only low gas-flow rate needed; welding electrode replaced easily as prefabricated assembly; external wire-feeding manipulator not needed; and welding process relatively forgiving of operator error.

  15. 33 CFR 154.2107 - Inerting, enriching, and diluting systems.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...protected from any potential internal or external ignition...inerting or enriching system may not be operated at... (m) An enriching system may use a base loading...in a vapor collection system if— (1) The flow rate of enriching...

  16. 46 CFR 154.908 - Inert gas generator: Location.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Inert gas generator: Location. 154.908 Section 154.908... Atmospheric Control in Cargo Containment Systems § 154.908 Inert gas generator: Location. (a) Except as allowed in paragraph (b) of this section, an inert gas generator must be located in the main...

  17. 46 CFR 154.908 - Inert gas generator: Location.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Inert gas generator: Location. 154.908 Section 154.908... Atmospheric Control in Cargo Containment Systems § 154.908 Inert gas generator: Location. (a) Except as allowed in paragraph (b) of this section, an inert gas generator must be located in the main...

  18. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Inert gas generators. 154.906 Section 154.906 Shipping... Atmospheric Control in Cargo Containment Systems § 154.906 Inert gas generators. The inert gas generator must... sample the discharge of the generator for oxygen content; and (c) Have an audible and visual alarm in...

  19. 46 CFR 154.908 - Inert gas generator: Location.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Inert gas generator: Location. 154.908 Section 154.908... Atmospheric Control in Cargo Containment Systems § 154.908 Inert gas generator: Location. (a) Except as allowed in paragraph (b) of this section, an inert gas generator must be located in the main...

  20. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Inert gas generators. 154.906 Section 154.906 Shipping... Atmospheric Control in Cargo Containment Systems § 154.906 Inert gas generators. The inert gas generator must... sample the discharge of the generator for oxygen content; and (c) Have an audible and visual alarm in...

  1. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Inert gas generators. 154.906 Section 154.906 Shipping... Atmospheric Control in Cargo Containment Systems § 154.906 Inert gas generators. The inert gas generator must... sample the discharge of the generator for oxygen content; and (c) Have an audible and visual alarm in...

  2. 46 CFR 154.908 - Inert gas generator: Location.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Inert gas generator: Location. 154.908 Section 154.908... Atmospheric Control in Cargo Containment Systems § 154.908 Inert gas generator: Location. (a) Except as allowed in paragraph (b) of this section, an inert gas generator must be located in the main...

  3. 46 CFR 154.908 - Inert gas generator: Location.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Inert gas generator: Location. 154.908 Section 154.908... Atmospheric Control in Cargo Containment Systems § 154.908 Inert gas generator: Location. (a) Except as allowed in paragraph (b) of this section, an inert gas generator must be located in the main...

  4. 46 CFR 154.903 - Inert gas systems: General.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Atmospheric Control in Cargo Containment Systems § 154.903 Inert gas systems: General. (a) Inert gas carried... tanks, hold and interbarrier spaces, and insulation. (b) The boiling point and dewpoint at atmospheric pressure of the inert gas must be below the temperature of any surface in those spaces or ?45 °C (?49...

  5. 46 CFR 154.903 - Inert gas systems: General.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Atmospheric Control in Cargo Containment Systems § 154.903 Inert gas systems: General. (a) Inert gas carried... tanks, hold and interbarrier spaces, and insulation. (b) The boiling point and dewpoint at atmospheric pressure of the inert gas must be below the temperature of any surface in those spaces or ?45 °C (?49...

  6. 46 CFR 154.903 - Inert gas systems: General.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Atmospheric Control in Cargo Containment Systems § 154.903 Inert gas systems: General. (a) Inert gas carried... tanks, hold and interbarrier spaces, and insulation. (b) The boiling point and dewpoint at atmospheric pressure of the inert gas must be below the temperature of any surface in those spaces or ?45 °C (?49...

  7. 46 CFR 154.908 - Inert gas generator: Location.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 2013-10-01 false Inert gas generator: Location. 154.908 Section 154...Containment Systems § 154.908 Inert gas generator: Location. (a) Except as allowed...paragraph (b) of this section, an inert gas generator must be located in the main...

  8. 46 CFR 154.908 - Inert gas generator: Location.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 2014-10-01 false Inert gas generator: Location. 154.908 Section 154...Containment Systems § 154.908 Inert gas generator: Location. (a) Except as allowed...paragraph (b) of this section, an inert gas generator must be located in the main...

  9. 46 CFR 154.908 - Inert gas generator: Location.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 2011-10-01 false Inert gas generator: Location. 154.908 Section 154...Containment Systems § 154.908 Inert gas generator: Location. (a) Except as allowed...paragraph (b) of this section, an inert gas generator must be located in the main...

  10. 46 CFR 154.908 - Inert gas generator: Location.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 2012-10-01 false Inert gas generator: Location. 154.908 Section 154...Containment Systems § 154.908 Inert gas generator: Location. (a) Except as allowed...paragraph (b) of this section, an inert gas generator must be located in the main...

  11. 46 CFR 154.908 - Inert gas generator: Location.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 2010-10-01 false Inert gas generator: Location. 154.908 Section 154...Containment Systems § 154.908 Inert gas generator: Location. (a) Except as allowed...paragraph (b) of this section, an inert gas generator must be located in the main...

  12. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...: (a) Produce an inert gas containing less than 5% oxygen by volume; (b) Have a device to continuously sample the discharge of the generator for oxygen content; and (c) Have an audible and visual alarm in the cargo control station that alarms when the inert gas contains 5% or more oxygen by volume....

  13. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...: (a) Produce an inert gas containing less than 5% oxygen by volume; (b) Have a device to continuously sample the discharge of the generator for oxygen content; and (c) Have an audible and visual alarm in the cargo control station that alarms when the inert gas contains 5% or more oxygen by volume....

  14. 46 CFR 154.903 - Inert gas systems: General.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Construction and Equipment Atmospheric Control in Cargo Containment...boiling point and dewpoint at atmospheric pressure of the inert gas must be below the...c) For the temperatures and pressures at which the gas is stored...

  15. 46 CFR 154.903 - Inert gas systems: General.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Construction and Equipment Atmospheric Control in Cargo Containment...boiling point and dewpoint at atmospheric pressure of the inert gas must be below the...c) For the temperatures and pressures at which the gas is stored...

  16. 46 CFR 154.903 - Inert gas systems: General.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Construction and Equipment Atmospheric Control in Cargo Containment...boiling point and dew point at atmospheric pressure of the inert gas must be below the...c) For the temperatures and pressures at which the gas is stored...

  17. 46 CFR 154.903 - Inert gas systems: General.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Construction and Equipment Atmospheric Control in Cargo Containment...boiling point and dewpoint at atmospheric pressure of the inert gas must be below the...c) For the temperatures and pressures at which the gas is stored...

  18. 46 CFR 154.903 - Inert gas systems: General.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Construction and Equipment Atmospheric Control in Cargo Containment...boiling point and dewpoint at atmospheric pressure of the inert gas must be below the...c) For the temperatures and pressures at which the gas is stored...

  19. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Construction and Equipment Atmospheric Control in Cargo Containment...gas containing less than 5% oxygen by volume; (b) Have...discharge of the generator for oxygen content; and (c) Have...inert gas contains 5% or more oxygen by...

  20. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Construction and Equipment Atmospheric Control in Cargo Containment...gas containing less than 5% oxygen by volume; (b) Have...discharge of the generator for oxygen content; and (c) Have...inert gas contains 5% or more oxygen by...

  1. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Construction and Equipment Atmospheric Control in Cargo Containment...gas containing less than 5% oxygen by volume; (b) Have...discharge of the generator for oxygen content; and (c) Have...inert gas contains 5% or more oxygen by...

  2. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Construction and Equipment Atmospheric Control in Cargo Containment...gas containing less than 5% oxygen by volume; (b) Have...discharge of the generator for oxygen content; and (c) Have...inert gas contains 5% or more oxygen by...

  3. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Construction and Equipment Atmospheric Control in Cargo Containment...gas containing less than 5% oxygen by volume; (b) Have...discharge of the generator for oxygen content; and (c) Have...inert gas contains 5% or more oxygen by...

  4. Inert-Gas Diffuser For Plasma Or Arc Welding

    NASA Technical Reports Server (NTRS)

    Gilbert, Jeffrey L.; Spencer, Carl N.; Hosking, Timothy J.

    1994-01-01

    Inert-gas diffuser provides protective gas cover for weld bead as it cools. Follows welding torch, maintaining continuous flow of argon over newly formed joint and prevents it from oxidizing. Helps to ensure welds of consistently high quality. Devised for plasma arc keyhole welding of plates of 0.25-in. or greater thickness, also used in tungsten/inert-gas and other plasma or arc welding processes.

  5. Apparatus For Metal/Inert-Gas Welding In Vacuum

    NASA Technical Reports Server (NTRS)

    Stocks, C. O.

    1994-01-01

    Metal/inert-gas welding-torch assembly operates in vacuum. Plasma generated in interior chamber and focused onto workpiece in vacuum. Pinch rollers feed wire to weld puddle. Controlled flow of plasma reduces dispersal in vacuum, preventing extinction.

  6. Analysis and Comparison of Aluminum Alloy Welded Joints Between Metal Inert Gas Welding and Tungsten Inert Gas Welding

    NASA Astrophysics Data System (ADS)

    Zhao, Lei; Guan, Yingchun; Wang, Qiang; Cong, Baoqiang; Qi, Bojin

    2015-09-01

    Surface contamination usually occurs during welding processing and it affects the welds quality largely. However, the formation of such contaminants has seldom been studied. Effort was made to study the contaminants caused by metal inert gas (MIG) welding and tungsten inert gas (TIG) welding processes of aluminum alloy, respectively. SEM, FTIR and XPS analysis was carried out to investigate the microstructure as well as surface chemistry. These contaminants were found to be mainly consisting of Al2O3, MgO, carbide and chromium complexes. The difference of contaminants between MIG and TIG welds was further examined. In addition, method to minimize these contaminants was proposed.

  7. 46 CFR 154.903 - Inert gas systems: General.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Inert gas systems: General. 154.903 Section 154.903 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Atmospheric Control in Cargo Containment...

  8. 46 CFR 154.903 - Inert gas systems: General.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Inert gas systems: General. 154.903 Section 154.903 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Atmospheric Control in Cargo Containment...

  9. 33 CFR 157.164 - Use of inert gas system.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Use of inert gas system. 157.164 Section 157.164 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION RULES FOR THE PROTECTION OF THE MARINE ENVIRONMENT RELATING TO TANK VESSELS CARRYING OIL IN BULK Crude Oil Washing (COW) System on...

  10. Production of light oil by injection of hot inert gas

    NASA Astrophysics Data System (ADS)

    Ruidas, Bidhan C.; Ganguly, Somenath

    2015-07-01

    Hot inert gas, when injected into an oil reservoir is capable of generating a vaporization-condensation drive and as a consequence, a preferential movement of the lighter components to the production well. This form of displacement is an important unit mechanism in hot flue-gas injection, or in thermal recovery from a watered-out oil reservoir. This article presents the movement of heat front vis-à-vis the changes in the saturation profile, and the gas-phase composition. The plateau in the temperature profile due to the exchange of latent heat, and the formation of water bank at the downstream are elaborated. The broadening of the vaporization-condensation zone with continued progression is discussed. The effect of inert gas temperature on the cumulative production of oil is reviewed. The results provide insight to the vaporization-condensation drive as a stand-alone mechanism. The paper underscores the relative importance of this mechanism, when operated in tandem with other processes in improved oil recovery and CO2 sequestration.

  11. Moving in extreme environments: inert gas narcosis and underwater activities.

    PubMed

    Clark, James E

    2015-01-01

    Exposure to the underwater environment for pleasure or work poses many challenges on the human body including thermal stress, barotraumas, decompression sickness as well as the acute effects of breathing gases under pressure. With the popularity of recreational self-contained underwater breathing apparatus (SCUBA) diving on the increase and deep inland dive sites becoming more accessible, it is important that we understand the effects of breathing pressurised gas at depth can have on the body. One of the common consequences of hyperbaric gas is the narcotic effect of inert gas. Nitrogen (a major component of air) under pressure can impede mental function and physical performance at depths of as little as 10 m underwater. With increased depth, symptoms can worsen to include confusion, disturbed coordination, lack of concentration, hallucinations and unconsciousness. Narcosis has been shown to contribute directly to up to 6% of deaths in divers and is likely to be indirectly associated with other diving incidents at depth. This article explores inert gas narcosis, the effect on divers' movement and function underwater and the proposed physiological mechanisms. Also discussed are some of the factors that affect the susceptibility of divers to the condition. In conclusion, understanding the cause of this potentially debilitating problem is important to ensure that safe diving practices continue. PMID:25713701

  12. Nuclear Technology. Course 28: Welding Inspection. Module 28-3, Tungsten Inert Gas (TIG), Metal Inert Gas (MIG) and Submerged Arc Welding.

    ERIC Educational Resources Information Center

    Espy, John

    This third in a series of ten modules for a course titled Welding Inspection presents the apparatus, process techniques, procedures, applications, associated defects, and inspection for the tungsten inert gas, metal inert gas, and submerged arc welding processes. The module follows a typical format that includes the following sections: (1)…

  13. Cytogenetic studies of stainless steel welders using the tungsten inert gas and metal inert gas methods for welding.

    PubMed

    Jelmert, O; Hansteen, I L; Langård, S

    1995-03-01

    Cytogenetic damage was studied in lymphocytes from 23 welders using the Tungsten Inert Gas (TIG), and 21 welders using the Metal Inert Gas (MIG) and/or Metal Active Gas (MAG) methods on stainless steel (SS). A matched reference group I, and a larger reference group II of 94 subjects studied during the same time period, was established for comparison. Whole blood conventional cultures (CC), cultures in which DNA synthesis and repair were inhibited (IC), and the sister chromatid exchange (SCE) assay were applied in the study. For the CC a statistically significant decrease in chromosome breaks and cells with aberrations was found for both TIG/SS and MIG/MAG/SS welders when compared with reference group II. A non-significant decrease was found for the corresponding parameters for the two groups of welders when compared with their matched referents. A statistically significant negative association was found between measurements of total chromium (Cr) in inhaled air and SCE, and a weaker negative correlation with hexavalent Cr (Cr(VI)) in air. In conclusion, no cytogenetic damage was found in welders exposed to the TIG/SS and MIG/MAG/SS welding fumes with low content of Cr and Ni. On the contrary, a decline in the prevalence of chromosomal aberrations was indicated in the TIG/SS and MIG/MAG/SS welders, possibly related to the suggested enhancement of DNA repair capacity at slightly elevated exposures. PMID:7885396

  14. Development of advanced inert-gas ion thrusters

    NASA Technical Reports Server (NTRS)

    Poeschel, R. L.

    1983-01-01

    Inert gas ion thruster technology offers the greatest potential for providing high specific impulse, low thrust, electric propulsion on large, Earth orbital spacecraft. The development of a thruster module that can be operated on xenon or argon propellant to produce 0.2 N of thrust at a specific impulse of 3000 sec with xenon propellant and at 6000 sec with argon propellant is described. The 30 cm diameter, laboratory model thruster is considered to be scalable to produce 0.5 N thrust. A high efficiency ring cusp discharge chamber was used to achieve an overall thruster efficiency of 77% with xenon propellant and 66% with argon propellant. Measurements were performed to identify ion production and loss processes and to define critical design criteria (at least on a preliminary basis).

  15. Inert-gas welding and brazing enclosure fabricated from sheet plastic

    NASA Technical Reports Server (NTRS)

    Wisner, J. P.

    1965-01-01

    Custom-fabricated plastic bag maintains an inert-gas atmosphere for welding and brazing certain metals. The bag fits over part of the workpieces and the welding and brazing tools. It is also used for metal brazing and fusion plating which require an inert-gas atmosphere.

  16. Hot cracking in tungsten inert gas welding of magnesium alloy AZ91D

    E-print Network

    Zhou, Wei

    Hot cracking in tungsten inert gas welding of magnesium alloy AZ91D W. Zhou*, T. Z. Long and C. K of the plates were produced using tungsten inert gas (TIG) welding method. The TIG arc was also used to deposit welding beads on some of the thin plates. No cracking was found in the butt joints. However, hot cracking

  17. Theory of inert gas-condensing vapor thermoacoustics: transport equations.

    PubMed

    Slaton, William V; Raspet, Richard; Hickey, Craig J; Hiller, Robert A

    2002-10-01

    The preceding paper [J. Acoust. Soc. Am. 112, 1414-1422 (2002)] derives the propagation equation for sound in an inert gas-condensing vapor mixture in a wet-walled pore with an imposed temperature gradient. In this paper the mass, enthalpy, heat, and work transport equations necessary to describe the steady-state operation of a wet-walled thermoacoustic refrigerator are derived and presented in a form suitable for numerical evaluation. The requirement that the refrigerator operate in the steady state imposes zero mass flux for each species through a cross section. This in turn leads to the evaluation of the mass flux of vapor in the system. The vapor transport and heat transport are shown to work in parallel to produce additional cooling power in the wet refrigerator. An idealized calculation of the coefficient of performance (COP) of a wet-walled thermoacoustic refrigerator is derived and evaluated for a refrigeration system. The results of this calculation indicate that the wet-walled system can improve the performance of thermoacoustic refrigerators. Several experimental and practical questions and problems that must be addressed before a practical device can be designed and tested are described. PMID:12398450

  18. Shock waves in a dilute granular gas

    NASA Astrophysics Data System (ADS)

    Reddy, M. H. Lakshminarayana; Ansumali, Santosh; Alam, Meheboob

    2014-12-01

    We study the evolution of shock waves in a dilute granular gas which is modelled using three variants of hydrodynamic equations: Euler, 10-moment and 14-moment models. The one-dimensional shock-wave problem is formulated and the resulting equations are solved numerically using a relaxation-type scheme. Focusing on the specific case of blast waves, the results on the density, the granular temperature, the skew temperature, the heat flux and the fourth moment are compared among three models. We find that the shock profiles are smoother for the 14-moment model compared to those predicted by the standard Euler equations. A shock-splitting phenomenon is observed in the skew granular temperature profiles for a blast wave.

  19. Oxidation Processes in Blowing Steel With Inert Gas into the Ladle

    NASA Astrophysics Data System (ADS)

    Gizatulin, R. A.; Valuev, D. V.; Trifonov, V. A.; Valueva, A. V.; Serikbol, A.

    2015-09-01

    This work reports the possible development of oxidative processes in a metal when treating the melt in the ladle under intensive stirring with an inert gas. The industrial data have been received, confirming the possibility of reducing the concentration of silicon and aluminum in the metal, as well as changing the slag chemical composition with the bath blowing with the inert gas through the top submerged lance.

  20. Performance and emission characteristics of the thermal barrier coated SI engine by adding argon inert gas to intake mixture.

    PubMed

    Karthikeya Sharma, T

    2015-11-01

    Dilution of the intake air of the SI engine with the inert gases is one of the emission control techniques like exhaust gas recirculation, water injection into combustion chamber and cyclic variability, without scarifying power output and/or thermal efficiency (TE). This paper investigates the effects of using argon (Ar) gas to mitigate the spark ignition engine intake air to enhance the performance and cut down the emissions mainly nitrogen oxides. The input variables of this study include the compression ratio, stroke length, and engine speed and argon concentration. Output parameters like TE, volumetric efficiency, heat release rates, brake power, exhaust gas temperature and emissions of NOx, CO2 and CO were studied in a thermal barrier coated SI engine, under variable argon concentrations. Results of this study showed that the inclusion of Argon to the input air of the thermal barrier coated SI engine has significantly improved the emission characteristics and engine's performance within the range studied. PMID:26644918

  1. Performance and emission characteristics of the thermal barrier coated SI engine by adding argon inert gas to intake mixture

    PubMed Central

    Karthikeya Sharma, T.

    2014-01-01

    Dilution of the intake air of the SI engine with the inert gases is one of the emission control techniques like exhaust gas recirculation, water injection into combustion chamber and cyclic variability, without scarifying power output and/or thermal efficiency (TE). This paper investigates the effects of using argon (Ar) gas to mitigate the spark ignition engine intake air to enhance the performance and cut down the emissions mainly nitrogen oxides. The input variables of this study include the compression ratio, stroke length, and engine speed and argon concentration. Output parameters like TE, volumetric efficiency, heat release rates, brake power, exhaust gas temperature and emissions of NOx, CO2 and CO were studied in a thermal barrier coated SI engine, under variable argon concentrations. Results of this study showed that the inclusion of Argon to the input air of the thermal barrier coated SI engine has significantly improved the emission characteristics and engine’s performance within the range studied. PMID:26644918

  2. Modelling of inert gas bubble behaviour during annealing of irradiated molybdenum

    NASA Astrophysics Data System (ADS)

    Chkuaseli, V. F.

    1992-06-01

    By theoretically studying the gas bubble evolution in molybdenum doped with heavy inert gas (Xe) a bimodal size distribution in a broad temperature region (1473-1973 K) is predicted. For molybdenum implanted with helium the size distribution is typical and has only a single peak. A modelling of gas porosity development was carried out using the assumption, that the basic mechanism of bubble nucleation and growth is the collision and coalescence of randomly migrating bubbles. An analysis of the calculation results leads to a conclusion, that the major cause of the formation of the bimodal size distribution is the existence of a deep bubble mobility minimum for molybdenum doped with heavy inert gas. The proposed mechanism of bimodal size distribution formation is supported by results obtained recently by Rest and Birtcher for nickel implanted with heavy inert gases.

  3. Continuous injection of an inert gas through a drill rig for drilling into potentially hazardous areas

    DOEpatents

    McCormick, Steve H. (Idaho Falls, ID); Pigott, William R. (Idaho Falls, ID)

    1997-01-01

    A drill rig for drilling in potentially hazardous areas includes a drill having conventional features such as a frame, a gear motor, gear box, and a drive. A hollow rotating shaft projects through the drive and frame. An auger, connected to the shaft is provided with a multiplicity of holes. An inert gas is supplied to the hollow shaft and directed from the rotating shaft to the holes in the auger. The inert gas flows down the hollow shaft, and then down the hollow auger and out through the holes in the bottom of the auger into the potentially hazardous area.

  4. Continuous injection of an inert gas through a drill rig for drilling into potentially hazardous areas

    DOEpatents

    McCormick, S.H.; Pigott, W.R.

    1997-12-30

    A drill rig for drilling in potentially hazardous areas includes a drill having conventional features such as a frame, a gear motor, gear box, and a drive. A hollow rotating shaft projects through the drive and frame. An auger, connected to the shaft is provided with a multiplicity of holes. An inert gas is supplied to the hollow shaft and directed from the rotating shaft to the holes in the auger. The inert gas flows down the hollow shaft, and then down the hollow auger and out through the holes in the bottom of the auger into the potentially hazardous area. 3 figs.

  5. Continuous injection of an inert gas through a drill rig for drilling into potentially hazardous areas

    SciTech Connect

    McCormick, S.H.; Pigott, W.R.

    1998-04-01

    A drill rig for drilling in potentially hazardous areas includes a drill having conventional features such as a frame, a gear motor, gear box, and a drive. A hollow rotating shaft projects through the drive and frame. An auger, connected to the shaft is provided with a multiplicity of holes. An inert gas is supplied to the hollow shaft and directed from the rotating shaft to the holes in the auger. The inert gas flows down the hollow shaft, and then down the hollow auger, and out through the holes in the bottom of the auger into the potentially hazardous area.

  6. An inverse approach to estimate bubble-mediated air-sea gas flux from inert gas measurements

    E-print Network

    Khatiwala, Samar

    in equilibrium with local sea level pressure (slp). As convention here, a positive flux is from atmosphereAn inverse approach to estimate bubble-mediated air-sea gas flux from inert gas measurements David, Ar, N2/Ar and Kr/Ar) to constrain the magnitude of bubble mediated air-sea gas flux. We illustrate

  7. The Propagation of Photons in the Dilute Ionized Gas

    E-print Network

    Yijia Zheng

    2013-05-02

    The dilute ionized gas is very popular in the Universe. Usually only the Compton interactions, the "Sunyaev-Zel'dovich" effect, were considered while photons propagated in this medium. In this paper the "soft-photon process" is considered. Due to the soft photons emitted during the propagation of a photon in the dilute ionized gas, the main photon (propagating in the original direction) will be redshifted. The formula to calculate this redshift is derived.

  8. Vacuum rated flow controllers for inert gas ion engines

    NASA Technical Reports Server (NTRS)

    Pless, L. C.

    1987-01-01

    Electrical propulsion systems which use a gas as a propellant require a gas flowmeter/controller which is capable of operating in a vacuum environment. The presently available instruments in the required flow ranges are designed and calibrated for use at ambient pressure. These instruments operate by heating a small diameter tube through which the gas is flowing and then sensing the change in temperature along the length of the tube. This temperature change is a function of the flow rate and the gas heat capacity. When installed in a vacuum, the change in the external thermal characteristics cause the tube to overheat and the temperature sensors are then operating outside their calibrated range. In addition, the variation in heat capacity with temperature limit the accuracy obtainable. These problems and the work in progress to solve them are discussed.

  9. Study of a volume discharge in inert-gas halides without preionisation

    SciTech Connect

    Erofeev, M V; Tarasenko, V F

    2008-04-30

    The energy characteristics of radiation of halides of inert gases excited by a volume discharge without additional preionisation are studied. The pressures of working mixtures and relations between the inert gas and halogen optimal for obtaining the maximum pulsed power and radiation efficiency are determined. The peak UV radiation power density achieved 5 kW cm{sup -2} and the radiation efficiency was {approx}5.5%. The pulse FWHM was 30-40 ns. (laser applications and other topics in quantum electronics)

  10. Inert gas rejection device for zinc-halogen battery systems

    DOEpatents

    Hammond, Michael J. (Sterling Heights, MI); Arendell, Mark W. (Warren, MI)

    1981-01-01

    An electrolytic cell for separating chlorine gas from other (foreign) gases, having an anode, a cathode assembly, an aqueous electrolyte, a housing, and a constant voltage power supply. The cathode assembly is generally comprised of a dense graphite electrode having a winding channel formed in the face opposing the anode, a gas impermeable (but liquid permeable) membrane sealed into the side of the cathode electrode over the channel, and a packing of graphite particles contained in the channel of the cathode electrode. The housing separates and parallelly aligns the anode and cathode assembly, and provides a hermetic seal for the cell. In operation, a stream of chlorine and foreign gases enters the cell at the beginning of the cathode electrode channel. The chlorine gas is dissolved into the electrolyte and electrochemically reduced into chloride ions. The chloride ions disfuse through the gas impermeable membrane, and are electrochemically oxidized at the anode into purified chlorine gas. The foreign gases do not participate in the above electrochemical reactions, and are vented from the cell at the end of the cathode electrode channel.

  11. Heat Transfer and Pressure Drop in Concentric Annular Flows of Binary Inert Gas Mixtures

    NASA Technical Reports Server (NTRS)

    Reid, R. S.; Martin, J. J.; Yocum, D. J.; Stewart, E. T.

    2007-01-01

    Studies of heat transfer and pressure drop of binary inert gas mixtures flowing through smooth concentric circular annuli, tubes with fully developed velocity profiles, and constant heating rate are described. There is a general lack of agreement among the constant property heat transfer correlations for such mixtures. No inert gas mixture data exist for annular channels. The intent of this study was to develop highly accurate and benchmarked pressure drop and heat transfer correlations that can be used to size heat exchangers and cores for direct gas Brayton nuclear power plants. The inside surface of the annular channel is heated while the outer surface of the channel is insulated. Annulus ratios range 0.5 < r* < 0.83. These smooth tube data may serve as a reference to the heat transfer and pressure drop performance in annuli, tubes, and channels having helixes or spacer ribs, or other surfaces.

  12. Gas dilution system results and application to acid rain utilities

    SciTech Connect

    Jolley-Souders, K.; Geib, R.; Dunn, C.

    1997-12-31

    In 1997, the United States EPA will remove restrictions preventing acid rain utilities from using gas dilution systems for calibration or linearity studies for continuous emissions monitoring, Test Method 205 in 40CFR51 requires that a gas dilution system must produce calibration gases whose measured values are within {+-}2% of predicted values. This paper presents the evaluation of the Environics/CalMat 2020 Dilution System for use in calibration studies. Internal studies show that concentrations generated by this unit are within {+-}0.5% of predicted values. Studies are being conducted by several acid rain utilities to evaluate the Environics/CalMat system using single minor component calibration standards. In addition, an internally generated study is being performed to demonstrate the system`s accuracy using a multi-component gas mixture. Data from these tests will be presented in the final version of the paper.

  13. Onboard Inert Gas Generation System/Onboard Oxygen Gas Generation System (OBIGGS/OBOGS) Study. Part 1; Aircraft System Requirements

    NASA Technical Reports Server (NTRS)

    Reynolds, Thomas L.; Bailey, Delbert B.; Lewinski, Daniel F.; Roseburg, Conrad M.; Palaszewski, Bryan (Technical Monitor)

    2001-01-01

    The purpose of this technology assessment is to define a multiphase research study program investigating Onboard Inert Gas Generation Systems (OBIGGS) and Onboard Oxygen Generation Systems (OBOGS) that would identify current airplane systems design and certification requirements (Subtask 1); explore state-of-the-art technology (Subtask 2); develop systems specifications (Subtask 3); and develop an initial system design (Subtask 4). If feasible, consideration may be given to the development of a prototype laboratory test system that could potentially be used in commercial transport aircraft (Subtask 5). These systems should be capable of providing inert nitrogen gas for improved fire cargo compartment fire suppression and fuel tank inerting and emergency oxygen for crew and passenger use. Subtask I of this research study, presented herein, defines current production aircraft certification requirements and design objectives necessary to meet mandatory FAA certification requirements and Boeing design and performance specifications. These requirements will be utilized for baseline comparisons for subsequent OBIGGS/OBOGS application evaluations and assessments.

  14. Research on inert gas narcosis and air velocity effects on metabolic performance

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The effects of air velocity on metabolic performance are studied by using high forced airflow in a closed environment as a mechanism to control the concentration of volatile animal wastes. Air velocities between 100 and 200 ft/min are without significant effects on the metabolism of rats. At velocities of 200 ft/min and above, oxygen consumption and CO2 production as well as food consumption increase. In most instances, the changes are on the order of 5-10%. At the same time, the RQ for the animals increases slightly and generally correlates well with oxygen consumption and CO2 production. Experiments on the nature of inert gas narcosis show that halothane and methoxyflurane are rather potent inhibitors of the NADH:O2 oxidoreductase system in rats. These experiments suggest that the mechanism of inert gas narcosis is not mandatorily related to a membrane surface phenomenon.

  15. A new gas dilution method for measuring body volume.

    PubMed Central

    Nagao, N; Tamaki, K; Kuchiki, T; Nagao, M

    1995-01-01

    This study was designed to examine the validity of a new gas dilution method (GD) for measuring human body volume and to compare its accuracy with the results obtained by the underwater weighing method (UW). We measured the volume of plastic bottles and 16 subjects (including two females), aged 18-42 years with each method. For the bottles, the volume measured by hydrostatic weighing was correlated highly (r = 1.000) with that measured by the new gas dilution method. For the subjects, the body volume determined by the two methods was significantly correlated (r = 0.998). However, the subject's volume measured by the gas dilution method was significantly larger than that by underwater weighing method. There was significant correlation (r = 0.806) between GD volume-UW volume and the body mass index (BMI), so that UW volume could be predicted from GD volume and BMI. It can be concluded that the new gas dilution method offers promising possibilities for future research in the population who cannot submerge underwater. PMID:7551760

  16. Continuous crafting of uniform colloidal nanocrystals using an inert-gas-driven microflow reactor

    NASA Astrophysics Data System (ADS)

    Tang, Hailong; He, Yanjie; Li, Bo; Jung, Jaehan; Zhang, Chuchu; Liu, Xiaobo; Lin, Zhiqun

    2015-05-01

    Recent research has witnessed rapid advances in synthesis of nanocrystals, which has led to the development of a large variety of approaches for producing nanocrystals with controlled dimensions. However, most of these techniques lack the high-throughput production. Herein, we report on a viable and robust strategy based on an inert-gas-driven microflow reactor for continuous crafting of high-quality colloidal nanocrystals. With the judicious introduction of the inert-gas driven capability, the microflow reactor provides an attractive platform for continuous production of colloidal nanocrystals in large quantities, including easily-oxidized nanocrystals. The as-synthesized nanocrystals possessed a uniform size and shape. Intriguingly, the size of nanocrystals can be effectively tailored by varying the flow rate and the precursor concentration. We envision that the microflow reactor strategy is general and offers easy access to a wide range of scalable nanocrystals for potential applications in sensors, optics, optoelectronics, solar energy conversion, batteries, photocatalysis, and electronic devices.Recent research has witnessed rapid advances in synthesis of nanocrystals, which has led to the development of a large variety of approaches for producing nanocrystals with controlled dimensions. However, most of these techniques lack the high-throughput production. Herein, we report on a viable and robust strategy based on an inert-gas-driven microflow reactor for continuous crafting of high-quality colloidal nanocrystals. With the judicious introduction of the inert-gas driven capability, the microflow reactor provides an attractive platform for continuous production of colloidal nanocrystals in large quantities, including easily-oxidized nanocrystals. The as-synthesized nanocrystals possessed a uniform size and shape. Intriguingly, the size of nanocrystals can be effectively tailored by varying the flow rate and the precursor concentration. We envision that the microflow reactor strategy is general and offers easy access to a wide range of scalable nanocrystals for potential applications in sensors, optics, optoelectronics, solar energy conversion, batteries, photocatalysis, and electronic devices. Electronic supplementary information (ESI) available: The schematic illustration of five functional sections and a digital image of the inert-gas-driven continuous microflow reactor are shown in Fig. S1. The digital images and PL spectrum of the Cu2S nanocrystals are shown in Fig. S2 and S3, respectively. TEM images of 2-D and 3-D self-assemblies of Cu2S nanocrystals are shown in Fig. S4. The experimental procedures for synthesis of Ag nanocrystals are provided, together with a TEM image, size distribution histogram and UV-vis spectrum (Fig. S5). See DOI: 10.1039/c5nr01492a

  17. TIG WELDER LOCATED IN THE CLEAN ROOM OF THE TECHNICAL SERVICES BUILDING TSB - THE INERT GAS WELDING

    NASA Technical Reports Server (NTRS)

    1963-01-01

    TIG WELDER LOCATED IN THE CLEAN ROOM OF THE TECHNICAL SERVICES BUILDING TSB - THE INERT GAS WELDING FACILITY IS USED FOR WELDING REFRACTORY METALS IN CONNECTION WITH THE COLUMBIUM LIQUID SODIUM LOOP PROJECT

  18. Modeling syngas-fired gas turbine engines with two dilutants

    NASA Astrophysics Data System (ADS)

    Hawk, Mitchell E.

    2011-12-01

    Prior gas turbine engine modeling work at the University of Wyoming studied cycle performance and turbine design with air and CO2-diluted GTE cycles fired with methane and syngas fuels. Two of the cycles examined were unconventional and innovative. The work presented herein reexamines prior results and expands the modeling by including the impacts of turbine cooling and CO2 sequestration on GTE cycle performance. The simple, conventional regeneration and two alternative regeneration cycle configurations were examined. In contrast to air dilution, CO2 -diluted cycle efficiencies increased by approximately 1.0 percentage point for the three regeneration configurations examined, while the efficiency of the CO2-diluted simple cycle decreased by approximately 5.0 percentage points. For CO2-diluted cycles with a closed-exhaust recycling path, an optimum CO2-recycle pressure was determined for each configuration that was significantly lower than atmospheric pressure. Un-cooled alternative regeneration configurations with CO2 recycling achieved efficiencies near 50%, which was approximately 3.0 percentage points higher than the conventional regeneration cycle and simple cycle configurations that utilized CO2 recycling. Accounting for cooling of the first two turbine stages resulted in a 2--3 percentage point reduction in un-cooled efficiency, with air dilution corresponding to the upper extreme. Additionally, when the work required to sequester CO2 was accounted for, cooled cycle efficiency decreased by 4--6 percentage points, and was more negatively impacted when syngas fuels were used. Finally, turbine design models showed that turbine blades are shorter with CO2 dilution, resulting in fewer design restrictions.

  19. Multiple inert gas elimination technique by micropore membrane inlet mass spectrometry--a comparison with reference gas chromatography.

    PubMed

    Kretzschmar, Moritz; Schilling, Thomas; Vogt, Andreas; Rothen, Hans Ulrich; Borges, João Batista; Hachenberg, Thomas; Larsson, Anders; Baumgardner, James E; Hedenstierna, Göran

    2013-10-15

    The mismatching of alveolar ventilation and perfusion (VA/Q) is the major determinant of impaired gas exchange. The gold standard for measuring VA/Q distributions is based on measurements of the elimination and retention of infused inert gases. Conventional multiple inert gas elimination technique (MIGET) uses gas chromatography (GC) to measure the inert gas partial pressures, which requires tonometry of blood samples with a gas that can then be injected into the chromatograph. The method is laborious and requires meticulous care. A new technique based on micropore membrane inlet mass spectrometry (MMIMS) facilitates the handling of blood and gas samples and provides nearly real-time analysis. In this study we compared MIGET by GC and MMIMS in 10 piglets: 1) 3 with healthy lungs; 2) 4 with oleic acid injury; and 3) 3 with isolated left lower lobe ventilation. The different protocols ensured a large range of normal and abnormal VA/Q distributions. Eight inert gases (SF6, krypton, ethane, cyclopropane, desflurane, enflurane, diethyl ether, and acetone) were infused; six of these gases were measured with MMIMS, and six were measured with GC. We found close agreement of retention and excretion of the gases and the constructed VA/Q distributions between GC and MMIMS, and predicted PaO2 from both methods compared well with measured PaO2. VA/Q by GC produced more widely dispersed modes than MMIMS, explained in part by differences in the algorithms used to calculate VA/Q distributions. In conclusion, MMIMS enables faster measurement of VA/Q, is less demanding than GC, and produces comparable results. PMID:23869066

  20. Gas turbine annular combustor with radial dilution air injection

    SciTech Connect

    Shekelton, J.R.; Johnson, D.C.

    1991-10-22

    This patent describes a radial flow gas turbine. It comprises: a rotor including turbine blades and a nozzle adjacent the turbine blades, the nozzle being adapted to direct hot gases at the turbine blades to cause rotation of the rotor; an annular combustor about the rotor and having a combustor outlet leading to the nozzle, the annular combustor having spaced inner and outer walls connected by a generally radially extending wall, the annular combustor including a combustion annulus defined by the inner, outer and radially extending walls upstream of the outlet; a dilution air annulus disposed downstream of the combustion annulus and immediately radially outwardly of the nozzle axially adjacent to and immediately downstream of the combustor outlet of the annular combustion; and a housing substantially surrounding the annular combustor in spaced relation to the inner, outer and radially extending walls thereof, the housing and walls together defining at least a portion of a dilution air flow path having a compressed air inlet in communication with a compressor for supplying dilution air at one end thereof, a turbine nozzle shroud and the inner wall defining the remainder of the dilution air flow path, the compressed air outlet injecting dilution air directly across the combustor outlet toward the compressed air inlet, the illusion air being injected into the hot gases at generally a right angle thereto assist hot gases approach the combustor outlet, the compressed air outlet being in communication with the dilution air annulus directly through the combustor outlet of the annular combustor downstream of the combustion annulus.

  1. Absorptive separation of NO from dilute off-gas

    SciTech Connect

    Zapfel, W.; Marr, R.; Siebenhofer, M.

    1999-04-01

    With regard to its negligible absorption properties, the separation of nitrogen monoxide from dilute off-gas is limited to bench-scale experiments. Investigation has been centered on improving the rate of absorption by the use of complex-forming additives based on iron(II) compounds. Further efforts have been made to improve the separation efficiency by the use of reactive additives. Due to the low reactivity of nitrogen monoxide, these attempts did not succeed. The oxidation of moderately concentrated off-gas with ozone and the absorption of the so-formed nitrogen dioxide have been reported. Technical as well as economical considerations do not permit the application of the process to the treatment of dilute off-gas. The principle underlying this process led to the investigation of direct oxidation of the off-gas under electrical discharge followed by absorption with aqueous diamide solution. Temperature and moisture of the off-gas have been considered, in addition to various feed contents of nitrogen monoxide. The results of this investigation show that direct oxidation of nitrogen monoxide by corona discharge is possible. The rate of conversion increases with increasing gas velocity, accompanied by a decreasing specific energy consumption. Applied to tunnel off-gas purification, the direct oxidation route seems to offer promising technical boundaries as it is accompanied by efficient particle separation.

  2. Entropy Production and Thermal Conductivity of A Dilute Gas

    E-print Network

    Yong-Jun Zhang

    2011-02-16

    It is known that the thermal conductivity of a dilute gas can be derived by using kinetic theory. We present here a new derivation by starting with two known entropy production principles: the steepest entropy ascent (SEA) principle and the maximum entropy production (MEP) principle. A remarkable feature of the new derivation is that it does not require the specification of the existence of the temperature gradient. The known result is reproduced in a similar form.

  3. 30 CFR 36.49 - Tests of exhaust-gas dilution system.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Tests of exhaust-gas dilution system. 36.49... TRANSPORTATION EQUIPMENT Test Requirements § 36.49 Tests of exhaust-gas dilution system. The performance and adequacy of the exhaust-gas dilution system shall be determined in tests of the complete equipment....

  4. Quantitative analysis of trace bulk oxygen in silicon wafers using an inert gas fusion method.

    PubMed

    Uchihara, Hiroshi; Ikeda, Masahiko; Nakahara, Taketoshi

    2003-11-01

    This paper describes a method for removing oxide film from the surface of silicon wafers using an inert gas fusion impulse furnace and precise determination of bulk oxygen within the wafer. A silicon wafer was cut to about 0.35 g (6 x 13 x 2 mm) and dropped into a graphite crucible. The sample was then heated for 40 s at 1300 degrees C. The wafer's oxide film was reduced by carbon and removed as carbon monoxide. The treated silicon sample was taken out of the graphite crucible and maintained again with the holder of the oxygen analyzer. The graphite crucible was then heated to 2100 degrees C. The treated silicon sample was dropped into the heated graphite crucible and the trace bulk oxygen in the wafer was measured using the inert gas fusion infrared absorption method. The relative standard deviations of the oxygen in silicon wafer samples with the removed surface oxide film were determined to be 0.8% for 9.8 x 10(17) atoms/cm3, and 2.7% for 13.0 x 10(17) atoms/cm3. PMID:14640456

  5. Effect of ethanol, temperature, and gas flow rate on volatile release from aqueous solutions under dynamic headspace dilution conditions.

    PubMed

    Tsachaki, Maroussa; Gady, Anne-Laure; Kalopesas, Michalis; Linforth, Robert S T; Athès, Violaine; Marin, Michele; Taylor, Andrew J

    2008-07-01

    On the basis of a mechanistic model, the overall and liquid mass transfer coefficients of aroma compounds were estimated during aroma release when an inert gas diluted the static headspace over simple ethanol/water solutions (ethanol concentration = 120 mL x L(-1)). Studied for a range of 17 compounds, they were both increased in the ethanol/water solution compared to the water solution, showing a better mass transfer due to the presence of ethanol, additively to partition coefficient variation. Thermal imaging results showed differences in convection of the two systems (water and ethanol/water) arguing for ethanol convection enhancement inside the liquid. The effect of ethanol in the solution on mass transfer coefficients at different temperatures was minor. On the contrary, at different headspace dilution rates, the effect of ethanol in the solution helped to maintain the volatile headspace concentration close to equilibrium concentration, when the headspace was replenished 1-3 times per minute. PMID:18529063

  6. Inert gas beam delivery for ultrafast laser micromachining at ambient pressure

    SciTech Connect

    Sun, J.; Longtin, J. P.

    2001-06-15

    Ultrafast laser micromachining is realized by focusing a femtosecond laser beam to a small spot, where very high optical intensity is achieved at the workpiece. Often, however, the beam must pass through a gas, e.g., air, before reaching the workpiece. At the very high laser intensities associated with ultrafast lasers, the gas can ionize, resulting in a rapid increase in free electron (plasma) density, which decreases the gas refractive index, resulting in plasma defocusing and self-phase modulation. Plasma-induced effects distort the temporal and spatial profile of the laser beam, which degrade feature quality and repeatability for ultrafast laser micromachining. In addition, plasma absorption reduces the energy available for materials processing, resulting in a decreased material removal rate. To avoid these effects, processing has traditionally been performed in a vacuum chamber, however this makes real-time processing on a large scale impractical. This article presents a beam delivery technique that uses inert gas as the beam propagation environment instead of air or a vacuum chamber. Plasma defocusing, self-phase modulation, and shielding effects are minimized due to the higher ionization potential of inert gas and thus less plasma forms along the beam path. Experiments were performed by delivering Ti:Sapphire femtosecond laser pulses in four different environmental gases: air, nitrogen, neon, and helium, to machine holes through a copper plate, with the best feature quality and machining efficiency obtained in helium and the worst in air. This technique shows potential as an innovative method to maintain high beam quality without the need for a vacuum chamber, which significantly improves processing throughput in practical ultrafast laser applications. {copyright} 2001 American Institute of Physics.

  7. Experimental observations of effects of inert gas on cavity formation during irradiation

    SciTech Connect

    Farrell, K.

    1980-04-01

    Cavity (void) formation and swelling in non-fissile materials during neutron irradiation and charged particle bombardments are reviewed. Helium is the most important inert gas and is primarily active as a cavity nucleant. It also enhances formation of dislocation structure. Preimplantation of helium overstimulates cavity nucleation and gives a different temperature response of swelling than when helium is coimplanted during the damage process. Helium affects, and is affected by, radiation-induced phase instability. Many of these effects are explainable in terms of cavity nucleation on submicroscopic critical size gas bubbles, and on the influence of the neutral sink strength of such bubbles. Titanium and zirconium resist cavity formation when vacancy loops are present.

  8. Comparison of inert-gas-fusion and modified Kjeldahl techniques for determination of nitrogen in niobium alloys

    NASA Technical Reports Server (NTRS)

    Merkle, E. J.; Graab, J. W.; Davis, W. F.

    1974-01-01

    This report compares results obtained for the determination of nitrogen in a selected group of niobium-base alloys by the inert-gas-fusion and the Kjeldahl procedures. In the inert-gas-fusion procedure the sample is heated to approximately 2700 C in a helium atmosphere in a single-use graphite crucible. A platinum flux is used to facilitate melting of the sample. The Kjeldahl method consisted of a rapid decomposition with a mixture of hydrofluoric acid, phosphoric acid, and potassium chromate; distillation in the presence of sodium hydroxide; and highly sensitive spectrophotometry with nitroprusside-catalyzed indophenol. In the 30- to 80-ppm range, the relative standard deviation was 5 to 7 percent for the inert-gas-fusion procedure and 2 to 8 percent for the Kjeldahl procedure. The agreement of the nitrogen results obtained by the two techniques is considered satisfactory.

  9. Argon: Systematic Review on Neuro- and Organoprotective Properties of an “Inert” Gas

    PubMed Central

    Höllig, Anke; Schug, Anita; Fahlenkamp, Astrid V.; Rossaint, Rolf; Coburn, Mark

    2014-01-01

    Argon belongs to the group of noble gases, which are regarded as chemically inert. Astonishingly some of these gases exert biological properties and during the last decades more and more reports demonstrated neuroprotective and organoprotective effects. Recent studies predominately use in vivo or in vitro models for ischemic pathologies to investigate the effect of argon treatment. Promising data has been published concerning pathologies like cerebral ischemia, traumatic brain injury and hypoxic ischemic encephalopathy. However, models applied and administration of the therapeutic gas vary. Here we provide a systematic review to summarize the available data on argon’s neuro- and organoprotective effects and discuss its possible mechanism of action. We aim to provide a summary to allow further studies with a more homogeneous setting to investigate possible clinical applications of argon. PMID:25310646

  10. Spraying of Metallic Powders by Hybrid Gas/Water Torch and the Effects of Inert Gas Shrouding

    NASA Astrophysics Data System (ADS)

    Kavka, T.; Mat?jí?ek, J.; Ctibor, P.; Hrabovský, M.

    2012-06-01

    A hybrid DC arc plasma torch, combining water and gas stabilization, offers a high flexibility in plasma characteristics. These can be controlled in a wide range by the torch operational parameters, such as arc current and secondary gas flow rate. In this study, their influence on plasma spraying of tungsten and copper was investigated. To suppress the in-flight oxidation of the metals, inert gas shrouding was applied. In-flight particle diagnostics and analysis of free-flight particles and coatings was performed for spraying experiments in the open atmosphere and with argon shrouding. Both in-flight particle behavior and coating properties were found to be sensitive to the torch parameters. The application of shrouding was found to affect particle in-flight parameters, reduce the oxide content in the coatings and generally improve their properties, such as thermal conductivity. However, a different degree of these effects was observed for copper and tungsten.

  11. Inert Gas Enhanced Laser-Assisted Purification of Platinum Electron-Beam-Induced Deposits.

    PubMed

    Stanford, Michael G; Lewis, Brett B; Noh, Joo Hyon; Fowlkes, Jason D; Rack, Philip D

    2015-09-01

    Electron-beam-induced deposition patterns, with composition of PtC5, were purified using a pulsed laser-induced purification reaction to erode the amorphous carbon matrix and form pure platinum deposits. Enhanced mobility of residual H2O molecules via a localized injection of inert Ar-H2 (4%) is attributed to be the reactive gas species for purification of the deposits. Surface purification of deposits was realized at laser exposure times as low as 0.1 s. The ex situ purification reaction in the deposit interior was shown to be rate-limited by reactive gas diffusion into the deposit, and deposit contraction associated with the purification process caused some loss of shape retention. To circumvent the intrinsic flaws of the ex situ anneal process, in situ deposition and purification techniques were explored that resemble a direct write atomic layer deposition (ALD) process. First, we explored a laser-assisted electron-beam-induced deposition (LAEBID) process augmented with reactive gas that resulted in a 75% carbon reduction compared to standard EBID. A sequential deposition plus purification process was also developed and resulted in deposition of pure platinum deposits with high fidelity and shape retention. PMID:26126173

  12. Controlling the Neutron Yield from a Small Dense Plasma Focus using Deuterium-Inert Gas Mixtures

    SciTech Connect

    Bures, B. L.; Krishnan, M.; Eshaq, Y.

    2009-01-21

    The dense plasma focus (DPF) is a well known source of neutrons when operating with deuterium. The DPF is demonstrated to scale from 10{sup 4} n/pulse at 40 kA to >10{sup 12} n/pulse at 2 MA by non-linear current scaling as described in [1], which is itself based on the simple yet elegant model developed by Lee [2]. In addition to the peak current, the gas pressure controls the neutron yield. Recent published results suggest that mixing 1-5% mass fractions of Krypton increase the neutron yield per pulse by more than 10x. In this paper we present results obtained by mixing deuterium with Helium, Neon and Argon in a 500 J dense plasma focus operating at 140 kA with a 600 ns rise time. The mass density was held constant in these experiments at the optimum (pure) deuterium mass density for producing neutrons. A typical neutron yield for a pure deuterium gas charge is 2x10{sup 6}{+-}15% n/pulse. Neutron yields in excess of 10{sup 7}{+-}10% n/pulse were observed with low mass fractions of inert gas. Time integrated optical images of the pinch, soft x-ray measurements and optical emission spectroscopy where used to examine the pinch in addition to the neutron yield monitor and the fast scintillation detector. Work supported by Domestic Nuclear Detection Office under contract HSHQDC-08-C-00020.

  13. Electron temperature and density measurement of tungsten inert gas arcs with Ar-He shielding gas mixture

    NASA Astrophysics Data System (ADS)

    Kühn-Kauffeldt, M.; Marques, J.-L.; Forster, G.; Schein, J.

    2013-10-01

    The diagnostics of atmospheric welding plasma is a well-established technology. In most cases the measurements are limited to processes using pure shielding gas. However in many applications shielding gas is a mixture of various components including metal vapor in gas metal arc welding (GMAW). Shielding gas mixtures are intentionally used for tungsten inert gas (TIG) welding in order to improve the welding performance. For example adding Helium to Argon shielding gas allows the weld geometry and porosity to be influenced. Yet thermal plasmas produced with gas mixtures or metal vapor still require further experimental investigation. In this work coherent Thomson scattering is used to measure electron temperature and density in these plasmas, since this technique allows independent measurements of electron and ion temperature. Here thermal plasmas generated by a TIG process with 50% Argon and 50% Helium shielding gas mixture have been investigated. Electron temperature and density measured by coherent Thomson scattering have been compared to the results of spectroscopic measurements of the plasma density using Stark broadening of the 696.5 nm Argon spectral line. Further investigations of MIG processes using Thomson scattering technique are planned.

  14. Holographic cold nuclear matter as dilute instanton gas

    E-print Network

    Kazuo Ghoroku; Kouki Kubo; Motoi Tachibana; Tomoki Taminato; Fumihiko Toyoda

    2013-03-06

    We study cold nuclear matter based on the holographic gauge theory, where baryons are introduced as the instantons in the probe D8/D8 branes according to the Sakai-Sugimoto model. Within a dilute gas approximation of instantons, we search for the stable states via the variational method and fix the instanton size. We find the first order phase transition from the vacuum to the nuclear matter phase as we increase the chemical potential. At the critical chemical potential, we could see a jump in the baryon density from zero to a finite definite value. While the size of the baryon in the nuclear matter is rather small compared to the nucleus near the transition point, where the charge density is also small, it increases with the baryon density. Those behaviors obtained here are discussed by relating them to the force between baryons.

  15. Axion cosmology, lattice QCD and the dilute instanton gas

    E-print Network

    S. Borsanyi; M. Dierigl; Z. Fodor; S. D. Katz; S. W. Mages; D. Nogradi; J. Redondo; A. Ringwald; K. K. Szabo

    2015-08-27

    Axions are one of the most attractive dark matter candidates. The evolution of their number density in the early universe can be determined by calculating the topological susceptibility $\\chi(T)$ of QCD as a function of the temperature. Lattice QCD provides an ab initio technique to carry out such a calculation. A full result needs two ingredients: physical quark masses and a controlled continuum extrapolation from non-vanishing to zero lattice spacings. We determine $\\chi(T)$ in the quenched framework (infinitely large quark masses) and extrapolate its values to the continuum limit. The results are compared with the prediction of the dilute instanton gas approximation (DIGA). A nice agreement is found for the temperature dependence, whereas the overall normalization of the DIGA result still differs from the non-perturbative continuum extrapolated lattice results by a factor of order ten. We discuss the consequences of our findings for the prediction of the amount of axion dark matter.

  16. Axion cosmology, lattice QCD and the dilute instanton gas

    NASA Astrophysics Data System (ADS)

    Borsanyi, Sz.; Dierigl, M.; Fodor, Z.; Katz, S. D.; Mages, S. W.; Nogradi, D.; Redondo, J.; Ringwald, A.; Szabo, K. K.

    2016-01-01

    Axions are one of the most attractive dark matter candidates. The evolution of their number density in the early universe can be determined by calculating the topological susceptibility ? (T) of QCD as a function of the temperature. Lattice QCD provides an ab initio technique to carry out such a calculation. A full result needs two ingredients: physical quark masses and a controlled continuum extrapolation from non-vanishing to zero lattice spacings. We determine ? (T) in the quenched framework (infinitely large quark masses) and extrapolate its values to the continuum limit. The results are compared with the prediction of the dilute instanton gas approximation (DIGA). A nice agreement is found for the temperature dependence, whereas the overall normalization of the DIGA result still differs from the non-perturbative continuum extrapolated lattice results by a factor of order ten. We discuss the consequences of our findings for the prediction of the amount of axion dark matter.

  17. Axion cosmology, lattice QCD and the dilute instanton gas

    E-print Network

    Borsanyi, S; Fodor, Z; Katz, S D; Mages, S W; Nogradi, D; Redondo, J; Ringwald, A; Szabo, K K

    2015-01-01

    Axions are one of the most attractive dark matter candidates. The evolution of their number density in the early universe can be determined by calculating the topological susceptibility $\\chi(T)$ of QCD as a function of the temperature. Lattice QCD provides an ab initio technique to carry out such a calculation. A full result needs two ingredients: physical quark masses and a controlled continuum extrapolation from non-vanishing to zero lattice spacings. We determine $\\chi(T)$ in the quenched framework (infinitely large quark masses) and extrapolate its values to the continuum limit. The results are compared with the prediction of the dilute instanton gas approximation (DIGA). A nice agreement is found for the temperature dependence, whereas the overall normalization of the DIGA result still differs from the non-perturbative continuum extrapolated lattice results by a factor of order ten. We discuss the consequences of our findings for the prediction of the amount of axion dark matter.

  18. Bénard instabilities in a binary-liquid layer evaporating into an inert gas.

    PubMed

    Machrafi, H; Rednikov, A; Colinet, P; Dauby, P C

    2010-09-01

    A linear stability analysis is performed for a horizontal layer of a binary liquid of which solely the solute evaporates into an inert gas, the latter being assumed to be insoluble in the liquid. In particular, a water-ethanol system in contact with air is considered, with the evaporation of water being neglected (which can be justified for a certain humidity of the air). External constraints on the system are introduced by imposing fixed "ambient" mass fraction and temperature values at a certain effective distance above the free liquid-gas interface. The temperature is the same as at the bottom of the liquid layer, where, besides, a fixed mass fraction of the solute is presumed to be maintained. Proceeding from a (quasi-)stationary reference solution, neutral (monotonic) stability curves are calculated in terms of solutal/thermal Marangoni/Rayleigh numbers as functions of the wavenumber for different values of the ratio of the gas and liquid layer thicknesses. The results are also presented in terms of the critical values of the liquid layer thickness as a function of the thickness of the gas layer. The solutal and thermal Rayleigh and Marangoni effects are compared to one another. For a water-ethanol mixture of 10wt.% ethanol, it appears that the solutal Marangoni effect is by far the most important instability mechanism. Furthermore, its global action can be described within a Pearson-like model, with an appropriately defined Biot number depending on the wavenumber. On the other hand, it is also shown that, if taken into account, water evaporation has only minor quantitative consequences upon the results for this predominant, solutal Marangoni mechanism. PMID:20557893

  19. Effect of Inert Cover Gas on Performance of Radioisotope Stirling Space Power System

    SciTech Connect

    Carpenter, Robert; Kumar, V; Ore, C; Schock, Alfred

    2001-01-01

    This paper describes an updated Orbital design of a radioisotope Stirling power system and its predicted performance at the beginning and end of a six-year mission to the Jovian moon Europa. The design is based on General Purpose Heat Source (GPHS) modules identical to those previously developed and safety-qualified by the Department of Energy (DOE) which were successfully launched to Jupiter and Saturn by the Jet Propulsion Laboratory (JPL). In each generator, the heat produced by the decay of the Pu-238 isotope is converted to electric power by two free-piston Stirling engines and linear alternators developed by Stirling Technology Company (STC), and their rejected waste heat is transported to radiators by heat pipes. The principal difference between the proposed system design and previous Orbital designs (Or et al. 2000) is the thermal insulation between the heat source and the generator's housing. Previous designs had employed multifoil insulation, whereas the design described here employs Min-K-1800 thermal insulation. Such insulation had been successfully used by Teledyne and GE in earlier RTGs (Radioisotope Thermoelectric Generators). Although Min-K is a much poorer insulator than multifoil in vacuum and requires a substantially greater thickness for equivalent performance, it offers compensating advantages. Specifically it makes it possible to adjust the generator's BOM temperatures by filling its interior volume with inert cover gas. This makes it possible to meet the generator's BOM and EOM performance goals without exceeding its allowable temperature at the beginning of the mission.

  20. MOX and MOX with 237Np/241Am Inert Fission Gas Generation Comparison in ATR

    SciTech Connect

    G. S. Chang; M. Robel; W. J. Carmack; D. J. Utterbeck

    2006-06-01

    The treatment of spent fuel produced in nuclear power generation is one of the most important issues to both the nuclear community and the general public. One of the viable options to long-term geological disposal of spent fuel is to extract plutonium, minor actinides (MA), and potentially long-lived fission products from the spent fuel and transmute them into short-lived or stable radionuclides in currently operating light-water reactors (LWR), thus reducing the radiological toxicity of the nuclear waste stream. One of the challenges is to demonstrate that the burnup-dependent characteristic differences between Reactor-Grade Mixed Oxide (RG-MOX) fuel and RG-MOX fuel with MA Np-237 and Am 241 are minimal, particularly, the inert gas generation rate, such that the commercial MOX fuel experience base is applicable. Under the Advanced Fuel Cycle Initiative (AFCI), developmental fuel specimens in experimental assembly LWR-2 are being tested in the northwest (NW) I-24 irradiation position of the Advanced Test Reactor (ATR). The experiment uses MOX fuel test hardware, and contains capsules with MOX fuel consisting of mixed oxide manufactured fuel using reactor grade plutonium (RG-Pu) and mixed oxide manufactured fuel using RG-Pu with added Np/Am. This study will compare the fuel neutronics depletion characteristics of Case-1 RG-MOX and Case-2 RG-MOX with Np/Am.

  1. Thorium-232 exposure during tungsten inert gas arc welding and electrode sharpening.

    PubMed

    Saito, Hiroyuki; Hisanaga, Naomi; Okada, Yukiko; Hirai, Shoji; Arito, Heihachiro

    2003-07-01

    To assess the exposure of welders to thorium-232 (232Th) during tungsten inert gas arc (TIG) welding, airborne concentrations of 232Th in the breathing zone of the welder and background levels were measured. The radioactive concentrations were 1.11 x 10(-2) Bq/m3 during TIG welding of aluminum (TIG/Al), 1.78 x 10(-4) Bq/m3 during TIG welding of stainless steel (TIG/SS), and 1.93 x 10(-1) Bq/m3 during electrode sharpening, with 5.82 x 10(-5) Bq/m3 background concentration. Although the annual intake of 232Th estimated using these values did not exceed the annual limit intake (ALI, 1.6 x 10(2) Bq), we recommend reducing 232Th exposure by substituting thoriated electrodes with a thorium-free electrodes, setting up local ventilation systems, and by using respiratory protective equipment. It is also necessary to inform workers that thoriated tungsten electrodes contain radioactive material. PMID:12916759

  2. Tensile properties of vanadium-base alloys with a tungsten/inert-gas weld zone

    SciTech Connect

    Loomis, B.A.; Konicek, C.F.; Nowicki, L.J.; Smith, D.L.

    1992-12-31

    The tensile properties of V-(0-20)Ti and V-(O-15)Cr-5Ti alloys after butt-joining by tungsten/inert-gas (TIG) welding were determined from tests at 25{degrees}C. Tensile tests were conducted on both annealed and cold-worked materials with a TIG weld zone. The tensile properties of these materials were strongly influenced by the microstructure in the heat-affected zone adjacent to the weld zone and by the intrinsic fracture toughness of the alloys. TIG weld zones in these vanadium-base alloys had tensile properties comparable to those of recrystallized alloys without a weld zone. Least affected by the TIG welding were tensile properties of the V-5Ti and V-5Cr-5Ti alloys. Although the tensile properties of the V-5Ti and V- 5Cr-5Ti alloys with a TIG weld zone were acceptable for structural material, these properties would be improved by optimization of the welding parameters for minimum grain size in the heat-affected zone.

  3. Tensile and flexural strength of commercially pure titanium submitted to laser and tungsten inert gas welds.

    PubMed

    Atoui, Juliana Abdallah; Felipucci, Daniela Nair Borges; Pagnano, Valéria Oliveira; Orsi, Iara Augusta; Nóbilo, Mauro Antônio de Arruda; Bezzon, Osvaldo Luiz

    2013-01-01

    This study evaluated the tensile and flexural strength of tungsten inert gas (TIG) welds in specimens made of commercially pure titanium (CP Ti) compared with laser welds. Sixty cylindrical specimens (2 mm diameter x 55 mm thick) were randomly assigned to 3 groups for each test (n=10): no welding (control), TIG welding (10 V, 36 A, 8 s) and Nd:YAG laser welding (380 V, 8 ms). The specimens were radiographed and subjected to tensile and flexural strength tests at a crosshead speed of 1.0 mm/min using a load cell of 500 kgf applied on the welded interface or at the middle point of the non-welded specimens. Tensile strength data were analyzed by ANOVA and Tukey's test, and flexural strength data by the Kruskal-Wallis test (?=0.05). Non-welded specimens presented significantly higher tensile strength (control=605.84 ± 19.83) (p=0.015) and flexural strength (control=1908.75) (p=0.000) than TIG- and laser-welded ones. There were no significant differences (p>0.05) between the welding types for neither the tensile strength test (TIG=514.90 ± 37.76; laser=515.85 ± 62.07) nor the flexural strength test (TIG=1559.66; laser=1621.64). As far as tensile and flexural strengths are concerned, TIG was similar to laser and could be suitable to replace laser welding in implant-supported rehabilitations. PMID:24474361

  4. Analysis of cracks in stainless steel TIG (tungsten inert gas) welds

    SciTech Connect

    Nakagaki, M.; Marschall, C.; Brust, F.

    1986-12-01

    This report contains the results of a combined experimental and analytical study of ductile crack growth in tungsten inert gas (TIG) weldments of austenitic stainless steel specimens. The substantially greater yield strength of the weld metal relative to the base metal causes more plastic deformation in the base metal adjacent to the weld than in the weld metal. Accordingly, the analytical studies focused on the stress-strain interaction between the crack tip and the weld/base-metal interface. Experimental work involved tests using compact (tension) specimens of three different sizes and pipe bend experiments. The compact specimens were machined from a TIG weldment in Type 304 stainless steel plate. The pipe specimens were also TIG welded using the same welding procedures. Elastic-plastic finite element methods were used to model the experiments. In addition to the J-integral, different crack-tip integral parameters such as ..delta..T/sub p/* and J were evaluated. Also, engineering J-estimation methods were employed to predict the load-carrying capacity of the welded pipe with a circumferential through-wall crack under bending.

  5. Formation of inorganic electride thin films via site-selective extrusion by energetic inert gas ions

    NASA Astrophysics Data System (ADS)

    Miyakawa, Masashi; Toda, Yoshitake; Hayashi, Katsuro; Hirano, Masahiro; Kamiya, Toshio; Matsunami, Noriaki; Hosono, Hideo

    2005-01-01

    Inert gas ion implantation (acceleration voltage 300kV) into polycrystalline 12CaO.7Al2O3 (C12A7) films was investigated with fluences from 1×1016 to 1×1017cm-2 at elevated temperatures. Upon hot implantation at 600°C with fluences greater than 1×1017cm-2, the obtained films were colored and exhibited high electrical conductivity in the as-implanted state. The extrusion of O2- ions encaged in the crystallographic cages of C12A7 crystal, which leaves electrons in the cages at concentrations up to ˜1.4×1021cm-3, may cause the high electrical conductivity. On the other hand, when the fluence is less than 1×1017cm-2, the as-implanted films are optically transparent and electrically insulating. The conductivity is enhanced and the films become colored by irradiating with ultraviolet light due to the formation of F +-like centers. The electrons forming the F+-like centers are photo released from the encaged H- ions, which are presumably derived from the preexisting OH- groups. The induced electron concentration is proportional to the calculated displacements per atom, which suggests that nuclear collision effects of the implanted ions play a dominant role in forming the electron and H- ion in the films. The hot ion implantation technique provides a nonchemical process for preparing electronic conductive C12A7 films.

  6. Joining titanium materials with tungsten inert gas welding, laser welding, and infrared brazing.

    PubMed

    Wang, R R; Welsch, G E

    1995-11-01

    Titanium has a number of desirable properties for dental applications that include low density, excellent biocompatibility, and corrosion resistance. However, joining titanium is one of the practical problems with the use of titanium prostheses. Dissolved oxygen and hydrogen may cause severe embrittlement in titanium materials. Therefore the conventional dental soldering methods that use oxygen flame or air torch are not indicated for joining titanium materials. This study compared laser, tungsten inert gas, and infrared radiation heating methods for joining both pure titanium and Ti-6Al-4V alloy. Original rods that were not subjected to joining procedures were used as a control method. Mechanical tests and microstructure analysis were used to evaluate joined samples. Mechanical tests included Vickers microhardness and uniaxial tensile testing of the strength of the joints and percentage elongation. Two-way analysis of variance and Duncan's multiple range test were used to compare mean values of tensile strength and elongation for significant differences (p < or = 0.05). Tensile rupture occurred in the joint region of all specimens by cohesive failure. Ti-6Al-4V samples exhibited significantly greater tensile strength than pure titanium samples. Samples prepared by the three joining methods had markedly lower tensile elongation than the control titanium and Ti-6Al-4V rods. The changes in microstructure and microhardness were studied in the heat-affected and unaffected zones. Microhardness values increased in the heat-affected zone for all the specimens tested. PMID:8809260

  7. On the Gas Dynamics of Inert-Gas-Assisted Laser Cutting of Steel Plate

    NASA Astrophysics Data System (ADS)

    Brandt, A. D.; Settles, G. S.; Scroggs, S. D.

    1996-11-01

    Laser beam cutting of sheet metal requires an assist gas to blow away the molten material. Since the assist-gas dynamics influences the quality and speed of the cut, the orientation of the gas nozzle with respect to the kerf is also expected to be important. A 1 kW cw CO2 laser with nitrogen assist gas was used to cut mild steel sheet of 1 to 4 mm thickness, using a sonic coaxial nozzle as a baseline. Off-axis nozzles were oriented from 20 deg to 60 deg from normal with exit Mach numbers from 1 to 2.4. Results showed maximum cutting speed at a 40 deg nozzle orientation. Shadowgrams of a geometrically-similar model kerf then revealed a separated shock wave-boundary layer interaction within the kerf for the (untilted) coaxial nozzle case. This was alleviated, resulting in a uniform supersonic flow throughout the kerf and consequent higher cutting speeds, by tilting the nozzle between 20 deg and 45 deg from the normal. This result did not depend upon the exit Mach number of the nozzle. (Research supported by NSF Grant DMI-9400119.)

  8. Electron-beam generation in a wide-aperture open gas discharge: A comparative study for different inert gases

    SciTech Connect

    Bokhan, P. A.; Zakrevsky, Dm. E.

    2010-08-30

    In the present study, electron-beam generation by open discharges was examined. The study was performed at gas pressures up to 20 Torr, and covered all inert gases. At voltages up to 8 kV, electron-beam currents up to 1600 A with current density {approx}130 A/cm{sup 2} and a beam generation efficiency in excess of 93% were obtained. The production of electrons from cold cathode was concluded to be of photoemissive nature, enabling the production of high-intensity electron beams in any noble gas or in a mixture of a noble gas with molecular gases irrespective of cathode material.

  9. Mobility of Supercooled liquid Toluene, Ethylbenzene, and Benzene near their Glass Transition Temperatures Investigated using Inert Gas Permeation

    SciTech Connect

    May, Robert A.; Smith, R. Scott; Kay, Bruce D.

    2013-11-21

    We investigate the mobility of supercooled liquid toluene, ethylbenzene, and benzene near their respective glass transition temperatures (Tg). The permeation rate of Ar, Kr, and Xe through the supercooled liquid created when initially amorphous overlayers heated above their glass transition temperature is used to determine the diffusivity. Amorphous benzene crystallizes at temperatures well below its Tg and as a result the inert gas underlayer remains trapped until the onset of benzene desorption. In contrast, for toluene and ethylbenzene the onset of inert gas permeation is observed at temperatues near Tg. The inert gas desorption peak temperature as a function of the heating rate and overlayer thickness is used to quantify the diffusivity of supercooled liquid toluene and ethylbenzene from 115 K to 135 K. In this temperature range, diffusivities are found to vary across five orders of magnitude (~10-14 to 10-9 cm2/s). These data are compared to viscosity measurements and used to determine the low temperature fractional Stokes-Einstein exponent. Efforts to determine the diffusivity of a mixture of benzene and ethylbenzene are detailed, and the effect of mixing these materials on benzene crystallization is explored using infrared spectroscopy.

  10. Characterization of InSb Nanoparticles Synthesized Using Inert Gas Condensation

    NASA Astrophysics Data System (ADS)

    Pandya, Sneha G.; Kordesch, Martin E.

    2015-06-01

    Nanoparticles (NPs) of indium antimonide (InSb) were synthesized using a vapor phase synthesis technique known as inert gas condensation (IGC). NPs were directly deposited, at room temperature and under high vacuum, on glass cover slides, TEM grids and (111) p-type silicon wafers. TEM studies showed a bimodal distribution in the size of the NPs with average particle size of 13.70 nm and 33.20 nm. The Raman spectra of InSb NPs exhibited a peak centered at 184.27 cm-1, which corresponds to the longitudinal optical (LO) modes of phonon vibration in InSb. A 1:1 In-to-Sb composition ratio was confirmed by energy dispersive X-ray (EDX). X-ray diffractometer (XRD) and high-resolution transmission electron microscopy (HRTEM) studies revealed polycrystalline behavior of these NPs with lattice spacing around 0.37 and 0.23 nm corresponding to the growth directions of (111) and (220), respectively. The average crystallite size of the NPs obtained using XRD peak broadening results and the Debye-Scherrer formula was 25.62 nm, and the value of strain in NPs was found to be 0.0015. NP's band gap obtained using spectroscopy and Fourier transform infrared (FTIR) spectroscopy was around 0.43-0.52 eV at 300 K, which is a blue shift of 0.26-0.35 eV. The effects of increased particle density resulting into aggregation of NPs are also discussed in this paper.

  11. A study of thorium exposure during tungsten inert gas welding in an airline engineering population.

    PubMed

    McElearney, N; Irvine, D

    1993-07-01

    To investigate the theoretic possibility of excessive exposure to thorium during the process of tungsten inert gas (TIG) welding using thoriated rods we carried out a cross-sectional study of TIG welders and an age- and skill-matched group. We measured the radiation doses from inhaled thorium that was retained in the body and investigated whether any differences in health or biologic indices could have been attributable to the welding and tip-grinding process. Sixty-four TIG welders, 11 non-TIG welders, and 61 control subjects from an airline engineering population participated. All of the subjects were interviewed for biographic, occupational history and morbidity details. All of the welders and eight control subjects carried out large-volume urine sampling to recover thorium 232 and thorium 228; this group also had chest radiographs. All of the subjects had a blood sample taken to estimate liver enzymes, and they provided small-volume urine samples for the estimation of retinol-binding protein and beta 2-microglobulin. We found no excess of morbidity among the TIG or non-TIG welding groups, and the levels of retinol-binding protein and beta 2-microglobulin were the same for both groups. There was a higher aspartate aminotransferase level in the control group. The internal radiation doses were estimated at less than an annual level of intake in all cases, and considerably less if the exposure (as was the case) was assumed to be chronic over many years. Some additional precautionary measures are suggested to reduce further any potential hazard from this process. PMID:8396174

  12. Inert gas narcosis disrupts encoding but not retrieval of long term memory.

    PubMed

    Hobbs, Malcolm; Kneller, Wendy

    2015-05-15

    Exposure to increased ambient pressure causes inert gas narcosis of which one symptom is long-term memory (LTM) impairment. Narcosis is posited to impair LTM by disrupting information encoding, retrieval (self-guided search), or both. The effect of narcosis on the encoding and retrieval of LTM was investigated by testing the effect of learning-recall pressure and levels of processing (LoP) on the free-recall of word lists in divers underwater. All participants (n=60) took part in four conditions in which words were learnt and then recalled at either low pressure (1.4-1.9atm/4-9msw) or high pressure (4.4-5.0atm/34-40msw), as manipulated by changes in depth underwater: low-low (LL), low-high(LH), high-high (HH), and high-low (HL). In addition, participants were assigned to either a deep or shallow processing condition, using LoP methodology. Free-recall memory ability was significantly impaired only when words were initially learned at high pressure (HH & HL conditions). When words were learned at low pressure and then recalled at low pressure (LL condition) or high pressure (LH condition) free-recall was not impaired. Although numerically superior in several conditions, deeper processing failed to significantly improve free-recall ability in any of the learning-recall conditions. This pattern of results support the hypothesis that narcosis disrupts encoding of information into LTM, while retrieval appears to be unaffected. These findings are discussed in relation to similar effects reported by some memory impairing drugs and the practical implications for workers in pressurised environments. PMID:25725120

  13. Characterization of InSb Nanoparticles Synthesized Using Inert Gas Condensation.

    PubMed

    Pandya, Sneha G; Kordesch, Martin E

    2015-12-01

    Nanoparticles (NPs) of indium antimonide (InSb) were synthesized using a vapor phase synthesis technique known as inert gas condensation (IGC). NPs were directly deposited, at room temperature and under high vacuum, on glass cover slides, TEM grids and (111) p-type silicon wafers. TEM studies showed a bimodal distribution in the size of the NPs with average particle size of 13.70 nm and 33.20 nm. The Raman spectra of InSb NPs exhibited a peak centered at 184.27 cm(-1), which corresponds to the longitudinal optical (LO) modes of phonon vibration in InSb. A 1:1 In-to-Sb composition ratio was confirmed by energy dispersive X-ray (EDX). X-ray diffractometer (XRD) and high-resolution transmission electron microscopy (HRTEM) studies revealed polycrystalline behavior of these NPs with lattice spacing around 0.37 and 0.23 nm corresponding to the growth directions of (111) and (220), respectively. The average crystallite size of the NPs obtained using XRD peak broadening results and the Debye-Scherrer formula was 25.62 nm, and the value of strain in NPs was found to be 0.0015. NP's band gap obtained using spectroscopy and Fourier transform infrared (FTIR) spectroscopy was around 0.43-0.52 eV at 300 K, which is a blue shift of 0.26-0.35 eV. The effects of increased particle density resulting into aggregation of NPs are also discussed in this paper. PMID:26061444

  14. Effect of inert species in gas phase on oscillatory dynamics of oxidation system of CO on Pt(100)

    NASA Astrophysics Data System (ADS)

    Hua, Da-Yin; Zhang, Feng; Ma, Yu-Qiang

    2003-05-01

    We present a Monte Carlo simulation for the global oscillation of the CO catalytic oxidation system in the presence of inert species in gas phase, which can adsorb and desorb on the catalytic surface but cannot react with other species. It is found that the impurity has a dramatic effect on the oscillatory dynamics, although it does not involve in the reaction of CO oxidation. The simulation results show that with an increase in the fraction of impurity in gas phase, the periodic oscillation may change into an irregular oscillation and even can be inhibited completely. However, as the desorption rate of the impurity is increased, the regular oscillation will be recovered again.

  15. Compatibility of Space Nuclear Power Plant Materials in an Inert He/Xe Working Gas Containing Reactive Impurities

    SciTech Connect

    MM Hall

    2006-01-31

    A major materials selection and qualification issue identified in the Space Materials Plan is the potential for creating materials compatibility problems by combining dissimilar reactor core, Brayton Unit and other power conversion plant materials in a recirculating, inert He/Xe gas loop containing reactive impurity gases. Reported here are results of equilibrium thermochemical analyses that address the compatibility of space nuclear power plant (SNPP) materials in high temperature impure He gas environments. These studies provide early information regarding the constraints that exist for SNPP materials selection and provide guidance for establishing test objectives and environments for SNPP materials qualification testing.

  16. Onboard Inert Gas Generation System/Onboard Oxygen Gas Generation System (OBIGGS/OBOGS) Study. Part 2; Gas Separation Technology--State of the Art

    NASA Technical Reports Server (NTRS)

    Reynolds, Thomas L.; Eklund, Thor I.; Haack, Gregory A.

    2001-01-01

    This purpose of this contract study task was to investigate the State of the Art in Gas Separation Technologies utilized for separating air into both nitrogen and oxygen gases for potential applications on commercial aircraft. The intended applications included: nitrogen gas for fuel tank inerting, cargo compartment fire protection, and emergency oxygen for passenger and crew use in the event of loss of cabin pressure. The approach was to investigate three principle methods of gas separation: Hollow Fiber Membrane (HFM), Ceramic Membrane (CM), and liquefaction: Total Atmospheric Liquefaction of Oxygen and Nitrogen (TALON). Additional data on the performance of molecular sieve pressure swing adsorption (PSA) systems was also collected and discussed. Performance comparisons of these technologies are contained in the body of the report.

  17. Method for extending the useful shelf-life of refrigerated red blood cells by flushing with inert gas

    DOEpatents

    Bitensky, Mark W. (Los Alamos, NM); Yoshida, Tatsuro (Los Alamos, NM)

    1997-01-01

    Method using oxygen removal for extending the useful shelf-life of refrigerated red blood cells. A cost-effective, 4.degree. C. storage procedure that preserves red cell quality and prolongs post-transfusion in vivo survival is described. Preservation of adenosine triphosphate levels and reduction in hemolysis and in membrane vesicle production of red blood cells stored at 4.degree. C. for prolonged periods of time is achieved by removing oxygen therefrom at the time of storage; in particular, by flushing with an inert gas. Adenosine triphosphate levels of the stored red blood cells are boosted in some samples by addition of ammonium phosphate.

  18. Method for extending the useful shelf-life of refrigerated red blood cells by flushing with inert gas

    DOEpatents

    Bitensky, M.W.; Yoshida, Tatsuro

    1997-04-29

    A method is disclosed using oxygen removal for extending the useful shelf-life of refrigerated red blood cells. A cost-effective, 4 C storage procedure that preserves red cell quality and prolongs post-transfusion in vivo survival is described. Preservation of adenosine triphosphate levels and reduction in hemolysis and in membrane vesicle production of red blood cells stored at 4 C for prolonged periods of time is achieved by removing oxygen from the red blood cells at the time of storage; in particular, by flushing with an inert gas. Adenosine triphosphate levels of the stored red blood cells are boosted in some samples by addition of ammonium phosphate. 4 figs.

  19. Dissipative fluid dynamics for the dilute Fermi gas at unitarity: Anisotropic fluid dynamics

    NASA Astrophysics Data System (ADS)

    Bluhm, M.; Schäfer, T.

    2015-10-01

    We consider the time evolution of a dilute atomic Fermi gas after release from a trapping potential. A common difficulty with using fluid dynamics to study the expansion of the gas is that the theory is not applicable in the dilute corona, and that a naive treatment of the entire cloud using fluid dynamics leads to unphysical results. We propose to remedy this problem by including certain nonhydrodynamic degrees of freedom, in particular anisotropic components of the pressure tensor, in the theoretical description. We show that, using this method, it is possible to describe the crossover from fluid dynamics to ballistic expansion locally. We illustrate the use of anisotropic fluid dynamics by studying the expansion of the dilute Fermi gas at unitarity using different functional forms of the shear viscosity, including a shear viscosity that is solely a function of temperature, ? ˜(mT ) 3 /2 , as predicted by kinetic theory in the dilute limit.

  20. CLOUDS TOWARD THE VIRGO CLUSTER PERIPHERY: GAS-RICH OPTICALLY INERT GALAXIES

    SciTech Connect

    Kent, Brian R.

    2010-12-20

    Aperture synthesis observations of two H I cloud complexes located in the periphery of the Virgo galaxy cluster are presented. These low H I-mass clouds (M{sub H{sub I}}< 10{sup 9} M{sub sun}) are seen projected on the M region of the western Virgo cluster, where the galaxy population is thought to lie behind the main A cluster surrounding M87. The kinematic measurements of both unresolved Arecibo and resolved Very Large Array (VLA)-C observations are in good agreement. The H I detections cannot be identified with any optical, IR, or UV emission from available archival imaging. They are inert at these wavelengths. The H I masses of the individual VLA detections range from 7.28 {<=} log(M{sub H{sub I}}/M{sub sun}){<=} 7.85. The total dynamical mass estimates are several times their H I content, ranging from 7.00 {<=} log(M{sub dyn}/M{sub sun}){<=} 9.07, with the assumption that the clouds are self-gravitating and in dynamical equilibrium. We report the observed parameters derived from the VLA observations. One of these H I clouds appears to be the most isolated optically inert detection observed in the outer reaches of Virgo.

  1. Clouds Toward the Virgo Cluster Periphery: Gas-rich Optically Inert Galaxies

    E-print Network

    Kent, Brian R

    2010-01-01

    Aperture synthesis observations of two HI cloud complexes located in the periphery of the Virgo galaxy cluster are presented. These low HI-mass clouds ($M_{HI}imaging. They are inert at these wavelengths. The HI masses of the individual VLA detections range from 7.28 $\\leq$ log($M_{HI}) \\leq $ 7.85. The total dynamical mass estimates are several times their HI content, ranging from 7.00 $\\leq$ log($M_{dyn}) \\leq $ 9.07, with the assumption that the clouds are self-gravitating and in dynamical equilibrium. We report the observed parameters derived from the VLA observations. One of these HI clouds appears to be the most isolated optically ...

  2. The effect of dilution on the gas retention behavior of Tank 241-SY- 103 waste

    SciTech Connect

    Bredt, P.R.; Tingey, S.M.

    1996-01-01

    Twenty-five of the 177 underground waste storage tanks on the Hanford Site have been placed on the Flammable Gas watch list. These 25 tanks, containing high-level waste generated during plutonium and uranium processing, have been identified as potentially capable of accumulating flammable gases above the lower flammability limit (Babad et al. 1991). In the case of Tanks 241-SY-101 and 241-SY-103, it has been proposed that diluting the tank waste may mitigate this hazard (Hudson et al. 1995; Stewart et al. 1994). The effect of dilution on the ability of waste from Tank 241-SY-103 to accumulate gas was studied at Pacific Northwest National Laboratory. A similar study has been completed for waste from Tank 241-SY-101 (Bredt et al. 1995). Because of the additional waste-storage volume available in Tank 241-SY-103 and because the waste is assumed to be similar to that currently in Tank 241-SY-101, Tank 241-SY-103 became the target for a demonstration of passive mitigation through in-tank dilution. In 1994, plans for the in-tank dilution demonstration were deferred pending a decision on whether to pursue dilution as a mitigation strategy. However, because Tank 241-SY-103 is an early retrieval target, determination of how waste properties vary with dilution will still be required.

  3. Computation of decompression schedules for single inert gas-oxygen dives using a hand-held programmable calculator.

    PubMed

    Ranade, A; Peterson, R E

    1980-08-01

    An algorithm for on-site computation with a hand-held programmable calculator (TI-59, Texas Instruments) of single inert-gas decompression schedules is described. This program is based on Workman's 'M-value' method. It can compute decompression schedules with changes in the oxygen content of the breathing mixture and extension of stay at any decompression stop. The features of the program that enable calculation of atypical dive profiles, along with the portability of small calculators, would make such an algorithm suitable for on-site applications. However, since dive profiles generated by the program have not yet been tested, divers are warned not to generate schedules until their safety has been established by field tests. PMID:6257447

  4. Parameter optimization of a microfabricated surface acoustic wave sensor for inert gas detection

    SciTech Connect

    Ahuja, S.; Ross, C.; Chien, H.T.; Raptis, A.C.

    1996-12-31

    This work is related to designing, fabricating, and testing a surface acoustic wave sensor to be used for detecting metastable inert gases, particularly helium. The assembly consists of two microsensor configurations: (a) a reference device with no deposition at the delay line and (b) a sensing device with an Au-activated TiO{sub 2} e-beam-deposited thin film on the delay line. The interdigitated transducers and delay lines are fabricated by photolithography techniques on a single Y-cut LiNbO{sub 3} substrate oriented for Z-propagation of the acoustic waves. Variation in electrical conductivity of the Au-activated TiO{sub 2} film due to exposure to metastable He is translated as a frequency change in the assembly. Various characteristics of the surface acoustic microsensor have been studied to better understand and optimize the variation of acoustic wave velocity and the operating frequency of the microdevice. Methods for the TiO{sub 2} thin-film deposition are discussed.

  5. 30 CFR 36.49 - Tests of exhaust-gas dilution system.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... with the data obtained from the engine test (see § 36.43) to determine that the concentrations of... TRANSPORTATION EQUIPMENT Test Requirements § 36.49 Tests of exhaust-gas dilution system. The performance and... engine, at temperature equilibrium, shall be operated in normal air as prescribed by MSHA. Samples of...

  6. 30 CFR 36.49 - Tests of exhaust-gas dilution system.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... with the data obtained from the engine test (see § 36.43) to determine that the concentrations of... TRANSPORTATION EQUIPMENT Test Requirements § 36.49 Tests of exhaust-gas dilution system. The performance and... engine, at temperature equilibrium, shall be operated in normal air as prescribed by MSHA. Samples of...

  7. 30 CFR 36.49 - Tests of exhaust-gas dilution system.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... with the data obtained from the engine test (see § 36.43) to determine that the concentrations of... TRANSPORTATION EQUIPMENT Test Requirements § 36.49 Tests of exhaust-gas dilution system. The performance and... engine, at temperature equilibrium, shall be operated in normal air as prescribed by MSHA. Samples of...

  8. 30 CFR 36.49 - Tests of exhaust-gas dilution system.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... with the data obtained from the engine test (see § 36.43) to determine that the concentrations of... TRANSPORTATION EQUIPMENT Test Requirements § 36.49 Tests of exhaust-gas dilution system. The performance and... engine, at temperature equilibrium, shall be operated in normal air as prescribed by MSHA. Samples of...

  9. A van der Waals Equation of State for a Dilute Boson Gas

    ERIC Educational Resources Information Center

    Deeney, F. A.; O'Leary, J. P.

    2012-01-01

    An equation of state of a system is a relationship that connects the thermodynamic variables of the system such as pressure and temperature. Such equations are well known for classical gases but less so for quantum systems. In this paper we develop a van der Waals equation of state for a dilute boson gas that may be used to explain the occurrence…

  10. Spectroscopy of Cosmic Carbon Analogs in Inert-Gas Matrices and in the Gas-Phase: Comparative Results and Perspectives for Astrophysics

    NASA Technical Reports Server (NTRS)

    Salama, Farid; DeVincenzi, Donald L. (Technical Monitor)

    2001-01-01

    Recent studies of the spectroscopy of large (up to approx. 50 carbon atoms) neutral and Ionized polycyclic aromatic hydrocarbons (PAHs) and Fullerenes isolated in inert gas matrices will be presented. The advantages and the limitations of matrix isolation spectroscopy for the study of the molecular spectroscopy of interstellar dust analogs will be discussed. The laboratory data will be compared to the astronomical spectra (the interstellar extinction, the diffuse interstellar bands). Finally, the spectra of PAH ions isolated in neon/argon matrices will be compared to the spectra obtained for PAH ion seeded in a supersonic expansion. The astrophysical implications and future perspectives will be discussed.

  11. Parametric Studies Of Weld Quality Of Tungsten Inert Gas Arc Welding Of Stainless Steel

    SciTech Connect

    Kumar Pal, Pradip; Nandi, Goutam; Ghosh, Nabendu

    2011-01-17

    Effect of current and gas flow rate on quality of weld in tungsten inter gas arc welding of austenitic stainless steel has been studied in the present work through experiments and analyses. Butt welded joints have been made by using several levels of current and gas flow rate. The quality of the weld has been evaluated in terms of ultimate and breaking strengths of the welded specimens. The observed data have been interpreted, discussed and analyzed by using Grey--Taguchi methodology. Optimum parametric setting has been predicted and validated as well.

  12. Modeled heating and surface erosion comparing motile (gas borne) and stationary (surface coating) inert particle additives

    SciTech Connect

    Buckingham, A.C.; Siekhaus, W.J.

    1982-09-27

    The unsteady, non-similar, chemically reactive, turbulent boundary layer equations are modified for gas plus dispersed solid particle mixtures, for gas phase turbulent combustion reactions and for heterogeneous gas-solid surface erosive reactions. The exterior (ballistic core) edge boundary conditions for the solutions are modified to include dispersed particle influences on core propellant combustion-generated turbulence levels, combustion reactants and products, and reaction-induced, non-isentropic mixture states. The wall surface (in this study it is always steel) is considered either bare or coated with a fixed particle coating which is conceptually non-reactive, insulative, and non-ablative. Two families of solutions are compared. These correspond to: (1) consideration of gas-borne, free-slip, almost spontaneously mobile (motile) solid particle additives which influence the turbulent heat transfer at the uncoated steel surface and, in contrast, (2) consideration of particle-free, gas phase turbulent heat transfer to the insulated surface coated by stationary particles. Significant differences in erosive heat transfer are found in comparing the two families of solutions over a substantial range of interior ballistic flow conditions. The most effective influences on reducing erosive heat transfer appear to favor mobile, gas-borne particle additives.

  13. Dilution Control in Gas-Tungsten-Arc Welds Involving Superaustenitic Stainless Steels and Nickel-Based Alloys

    E-print Network

    DuPont, John N.

    Dilution Control in Gas-Tungsten-Arc Welds Involving Superaustenitic Stainless Steels and Nickel stainless steel, (the AL-6XN alloy) and two Ni-based filler metals (IN625 and IN622) using the gas must also consider methods to control the dilution the welding of superaustenitic stainless steels

  14. Heat transfer coefficients of dilute flowing gas-solids suspensions

    NASA Technical Reports Server (NTRS)

    Kane, R. S.; Pfeffer, R.

    1973-01-01

    Heat transfer coefficients of air-glass, argon-glass, and argon-aluminum suspensions were measured in horizontal and vertical tubes. The glass, 21.6 and 36.0 micron diameter particles, was suspended at gas Reynolds numbers between 11,000 and 21,000 and loading ratios between 0 and 2.5. The presence of particles generally reduced the heat transfer coefficient. The circulation of aluminum powder in the 0.870 inch diameter closed loop system produced tenacious deposits on protuberances into the stream. In the vertical test section, the Nusselt number reduction was attributed to viscous sublayer thickening; in the horizontal test section to particle deposition.

  15. The effect of dilution on the gas-retention behavior of Tank 241-SY-101 waste

    SciTech Connect

    Bredt, P.R.; Tingey, S.M.; Shade, E.H.

    1995-09-01

    The effect of dilution on gas retention in waste from Tank 241-SY-101 was investigated. A composite sample was prepared from material collected during the Window ``C`` and Window ``E`` sampling events. The composite contained material from both the convective and nonconvective layer in the proportions existing in the tank. Operation of the mixer pump in Tank 241-SY-101 has homogenized the tank material, and dilution of the current waste would require additional mixing; therefore, no attempt was made to use unhomogenized tank waste to prepare the composite. The composite was diluted with 2 M NaOH at ratios of 0.5:1, 0.75: 1, 1:1, and 3:1 per volume (2 M NaOH:tank waste).

  16. EFFECT OF VENTILATION AND PERFUSION IMBALANCE ON INERT GAS REBREATHING VARIABLES

    EPA Science Inventory

    The effects of ventilation-to-perfusion (Va/Qc) maldistribution within the lungs on measured multiple gas rebreathing variables were studied in 14 dogs. The rebreathing method (using He, C18C, and C2H2) allows for measurements of pulmonary capillary blood flow (Qc), diffusing cap...

  17. High-density magnetohydrodynamic energy conversion in a high-temperature inert gas

    SciTech Connect

    Murakami, Tomoyuki; Okuno, Yoshihiro

    2008-07-28

    We describe high-density magnetohydrodynamic (MHD) energy conversion in a high-temperature seed-free argon plasma, for which a compact disk-shaped Hall-type radial-flow MHD electrical power generator is used. The state of the MHD power-generating plasma changes with increasing total inflow temperature from 8200 to 9400 K; unstable behavior accompanied by the appearance of fine structures is transformed to a homogeneous and stable state. The attained enthalpy extraction efficiency is comparable to previous results using a conventional seeded gas. Furthermore, a high power output density is achieved even in relatively low-density magnetic flux.

  18. Infrared spectroscopy of large protonated water clusters H+(H2O)20-50 cooled by inert gas attachment

    NASA Astrophysics Data System (ADS)

    Mizuse, Kenta; Fujii, Asuka

    2013-06-01

    We report infrared spectra of protonated water clusters H+(H2O)n (n = 20-50) cooled by H2 tagging. IR spectra show sharper features, validating the cooling effect of the H2 attachment even for the large clusters. Furthermore, the H2-mediated spectrum has indicated the origin of the first antimagic number (n = 22), which is a dangling water molecule on the cluster surface [K. Mizuse, A. Fujii, J. Phys. Chem. Lett. 2 (2011) 2130]. On the other hand, for the second magic (n = 28) and antimagic (n = 29) number clusters, no apparent difference is observed by the H2 tagging. IR spectra of Ar-tagged H+(H2O)20-22 are also measured. These spectra also show sharper features, however, no signature for the dangling water molecule is seen in n = 22. This result implies there are multiple isomer types in the n = 22 cluster and the observable type might vary with the choice of the inert gas for tagging.

  19. Low Temperature Cathodoluminescence Spectroscopy of Amorphous Aluminum Nitride Nanoparticles doped with Erbium, synthesized using Inert Gas Condensation Technique

    NASA Astrophysics Data System (ADS)

    Pandya, Sneha; Wang, Jingzhou; Wojciech, Jadwisienczak; Kordesch, Martin

    2015-03-01

    Free standing Aluminum Nitride Nanoparticles (NPs) doped in situwith Erbium (AlN:Er), ranging from 3-30nm in size, were synthesized using a vapor phase deposition technique known as Inert Gas Condensation (IGC). Amorphous behavior of these NPs was inferred from the wide-angle X-ray spectroscopy studies. Raman spectra analysis for these AlN:Er NPs showed characteristic peaks for A1(TO) and E2(high) phonon modes of AlN. Detailed structural characterization of these Er doped AlN NPs will be carried out using a High-Resolution TEM, results of which will be included in my talk. Low temperature Cathodoluminescence (CL) measurements were carried out for these a-AlN:Er NPs. The corresponding Er+3 ion emission peaks were compared to the CL emission spectra obtained for a-AlN:Er thin films, and for commercially obtained Erbium-Oxide NPs. These spectroscopic results will be discussed in detail. I will also present the CL results obtained for in-air and in-nitrogen atmosphere annealed a-AlN:Er NPs. In addition to this, I will illustrate how these Er doped NPs can be used as nano-scale temperature sensors. The SNOM help provided by Prof. Hugh Richardson is gratefully acknowledged.

  20. Synchrotron X-ray measurement and finite element analysis of residual strain in tungsten inert gas welded aluminum alloy 2024

    NASA Astrophysics Data System (ADS)

    Preston, R. V.; Shercliff, H. R.; Withers, P. J.; Hughes, D. J.; Smith, S. D.; Webster, P. J.

    2006-12-01

    Residual strains have been measured in a tungsten inert gas (TIG) butt-welded 2024 aluminum alloy plate using synchrotron X-ray diffraction. Novel two-dimensional strain maps spanning the entire plate reveal steep gradients in residual stress and provide detailed validation data for finite element (FE) analysis. Two variants of a FE model have been used to predict the residual strain distributions, incorporating different levels of plate constraint. The model uses decoupled thermal and elastic-plastic mechanical analyses and successfully predicts the longitudinal and transverse residual strain field over the entire weld. For butt weld geometries, the degree of transverse constraint is shown to be a significant boundary condition, compared to simpler bead-on-plate analyses. The importance of transverse residual strains for detailed model validation is highlighted, together with the need for care in selecting the location for line scans. The residual stress is largest in the heat-affected zone (HAZ), being equal to the local postweld yield stress, though the strength increases subsequently by natural aging. In addition, a halving of the diffraction line width has been observed local to the weld, and this correlates with the microstructural changes in the region.

  1. Abnormal distribution of microhardness in tungsten inert gas arc butt-welded AZ61 magnesium alloy plates

    SciTech Connect

    Xu Nan; Shen Jun; Xie Weidong; Wang Linzhi; Wang Dan; Min Dong

    2010-07-15

    In this study, the effects of heat input on the distribution of microhardness of tungsten inert gas (TIG) arc welded hot-extruded AZ61 magnesium alloy joints were investigated. The results show that with an increase of heat input, the distributions of microhardness at the top and bottom of the welded joints are different because they are determined by both the effect of grain coarsening and the effect of dispersion strengthening. With an increase of the heat input, the microhardness of the heat-affected zone (HAZ) at the top and bottom of welded joints and the fusion zone (FZ) at the bottom of welded joints decreased gradually, while the microhardness of the FZ at the top of welded joints decreased initially and then increased sharply. The reason for the abnormal distribution of microhardness of the FZ at the top of the welded joints is that this area is close to the heat source during welding and then large numbers of hard {beta}-Mg{sub 17}(Al,Zn){sub 12} particles are precipitated. Hence, in this case, the effect of dispersion strengthening dominated the microhardness.

  2. Influence of TIG welding thermal cycles on HSLA-100 steel plate. Technical report. [TIG (tungsten-inert gas)

    SciTech Connect

    Fox, A.G.; Bhole, S.D.

    1993-11-01

    A series of five bead on plate autogenous tungsten-inert-gas (TIG) welds were performed on U.S. Navy HSLA-100 steel. Power variations in these welds was achieved by altering the welding speed, voltage and current and were as follows (in kJ/mm); 0.7, 1.1, 1.2, 1.6 and 2.2. No evidence was found of either weld metal or underbead HAZ cracking in any of the welds illustrating the advantage of low carbon steel for both weld wire and base plate. Microhardness traverses across both the weld metals and HAZs gave a maximum. Vickers diamond pyramid hardness of 345 HV in the coarse grain HAZ next to the fusion line in the lowest power weld; for the highest power weld this was somewhat lower at 328 HV. These are well below 375 which is usually considered to be the lowest Vickers Hardness value for which severe hydrogen induced cold cracking is observed in this type of steel. Optical, scanning and transmission electron microscopy studies of the coarse grain HAZ microstructure in the regions of maximum hardness was correlated with the continuous cooling transformation diagram for this steel and good agreement between observed and predicted microstructures was obtained.

  3. Simulation and demonstration of magnetohydrodynamic energy conversion in a high-temperature inert gas

    SciTech Connect

    Murakami, Tomoyuki; Okuno, Yoshihiro

    2009-03-15

    The present paper describes high-density magnetohydrodynamic (MHD) energy conversion in a high-temperature seed-free argon plasma, for which a quasi-three-dimensional numerical simulation and a single-pulse shock-tunnel-based demonstration are conducted. The numerical model simulates the two-dimensional profiles of both the electron and the heavy-particle system of the supersonic argon plasma flow, of which the total inflow temperature is 8000 K. The MHD power-generating experiment clarifies the relationship between the plasma quality and the energy conversion efficiency as functions of the total inflow temperature (7600-9600 K) and the applied magnetic flux density (up to 4.0 T). The increase in the total inflow temperature from 7600 to 9400 K and the application of magnetic flux with density of 0.5-1.2 T change the plasma state; unstable behavior accompanied by an inhomogeneous structure is transformed to a homogeneous and stable state, which results in the significant improvement of the power generation performance. Even in low-density magnetic flux, the attained generator performance is comparable or superior to previous results obtained using a conventional low-temperature seeded gas.

  4. Theory of light and atom scattering in the Bose-Einstein condensate of a dilute gas

    SciTech Connect

    Avetisyan, Ya. A.; Trifonov, E. D.

    2006-11-15

    A semiclassical theory of superradiant light scattering from a Bose-Einstein condensate of a dilute gas is developed without recourse to the mean field approximation. The dynamics and spectrum of superradiant field, as well as the kinetics of formation of coherent atomic states with various translational momenta are calculated. The results are qualitatively consistent with experimental data for atoms scattered in the backward direction relative to that of the exciting laser beam propagation.

  5. Effects of ventilation on cardiac output determined by inert gas rebreathing.

    PubMed

    Damgaard, Morten; Norsk, Peter

    2005-05-01

    One of the most important methodological problems of the foreign gas rebreathing technique is that outcome of the measurements depends on procedural variables such as rebreathing frequency (RF), rebreathing bag volume (V(reb)), lung volume at start of rebreathing and intervals between measurements. Therefore, in 10 healthy males we investigated the effects of changes in ventilation pattern on cardiac output (CO) estimated by an N(2)O-rebreathing technique. Reducing the rebreathing volume (V(reb)) from 1.5 to 1.0 l diminished CO by 0.5 +/- 0.2 l min(-1), whereas an increase in V(reb) from 1.5 to 2.5 l had no effects. CO was 1.0 +/- 0.2 l min(-1) higher when, rebreathing was performed after a forced expiration than following a normal tidal expiration. Serial determinations of CO required a 3-min interval between the measurements to avoid effects of recirculation of N(2)O. Changing RF from 15 to 30 breaths min(-1) or adding serial dead space by up to 600 ml did not affect the determination of CO. In conclusion, the rebreathing procedure for determination of CO at rest should be performed following a normal tidal expiration with a rebreathing bag volume of between 1.5 and 2.5 l and with manoeuvres separated by at least 3-5 min. Variations in RF within the physiological range from 15 to 30 breaths min(-1) do not affect outcome of the measurements. PMID:15888093

  6. Ground-state properties of a dilute homogeneous Bose gas of hard disks in two dimensions

    SciTech Connect

    Mazzanti, F.; Polls, A.; Fabrocini, A.

    2005-03-01

    The energy and structure of a dilute hard-disks Bose gas are studied in the framework of a variational many-body approach based on a Jastrow correlated ground-state wave function. The asymptotic behaviors of the radial distribution function and the one-body density matrix are analyzed after solving the Euler equation obtained by a free minimization of the hypernetted chain energy functional. Our results show important deviations from those of the available low density expansions, already at gas parameter values x{approx}0.001. The condensate fraction in 2D is also computed and found generally lower than the 3D one at the same x.

  7. 46 CFR 154.1848 - Inerting.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...CARRYING BULK LIQUEFIED GASES Operations ...with full secondary barriers are inerted so...dry air or inert gas on: (i) A vessel...partial secondary barriers; (ii) A vessel with full secondary barriers when non-flammable...flammable vapor are to be gas freed, the...

  8. WVNS Tank Farm Process Support: Experimental evaluation of an inert gas (nitrogen) to mitigate external corrosion of high-level waste storage tanks

    SciTech Connect

    Elmore, M.R.

    1996-02-01

    Corrosion of the carbon steel waste storage tanks at West Valley Nuclear Services continues to be of concern, especially as the planned duration of waste storage time increases and sludge washing operations are conducted. The external surfaces of Tanks 8D-1 and 8D-2 have been exposed for more than 10 years to water that has intruded into the tank vaults. Visual inspection of the external tank surfaces using a remote video camera has shown indications of heavy corrosion in localized areas on the tank walls. Tests on mild steel specimens under simulated tank vault conditions showed that corrosion is related to the availability of oxygen for the corrosion reactions; consequently, removing oxygen as one of the reactants should effectively eliminate corrosion. In terms of the waste tanks, excluding oxygen from the annular vault space, such as by continuous flushing with an inert gas, should substantially decrease corrosion of the external surfaces of the mild steel tanks (100% exclusion of oxygen is probably not practicable). Laboratory corrosion testing was conducted at Pacific Northwest National Laboratory to give a preliminary assessment of the ability of nitrogen-inerting to reduce steel corrosion. This report summarizes test results obtained after 18-month corrosion tests comparing {open_quotes}nitrogen-inerted{close_quotes} corrosion with {open_quotes}air-equilibrated{close_quotes} corrosion under simulated tank vault conditions.

  9. Characteristics of dilute gas-solids suspensions in drag reducing flow

    NASA Technical Reports Server (NTRS)

    Kane, R. S.; Pfeffer, R.

    1973-01-01

    Measurements were performed on dilute flowing gas-solids suspensions and included data, with particles present, on gas friction factors, velocity profiles, turbulence intensity profiles, turbulent spectra, and particle velocity profiles. Glass beads of 10 to 60 micron diameter were suspended in air at Reynolds numbers of 10,000 to 25,000 and solids loading ratios from 0 to 4. Drag reduction was achieved for all particle sizes in vertical flow and for the smaller particle sizes in horizontal flow. The profile measurements in the vertical tube indicated that the presence of particles thickened the viscous sublayer. A quantitative theory based on particle-eddy interaction and viscous sublayer thickening has been proposed.

  10. Lyapunov Exponents from Kinetic Theory for a Dilute, Field-driven Lorentz Gas

    E-print Network

    H. van Beijeren; J. R. Dorfman; E. G. D. Cohen; H. A. Posch; Ch. Dellago

    1996-06-14

    Positive and negative Lyapunov exponents for a dilute, random, two-dimensional Lorentz gas in an applied field, $\\vec{E}$, in a steady state at constant energy are computed to order $E^{2}$. The results are: $\\lambda_{\\pm}=\\lambda_{\\pm}^{0}-a_{\\pm}(qE/mv)^{2}t_{0}$ where $\\lambda_{\\pm}^{0}$ are the exponents for the field-free Lorentz gas, $a_{+}=11/48, a_{-}=7/48$, $t_{0}$ is the mean free time between collisions, $q$ is the charge, $m$ the mass and $v$ is the speed of the particle. The calculation is based on an extended Boltzmann equation in which a radius of curvature, characterizing the separation of two nearby trajectories, is one of the variables in the distribution function. The analytical results are in excellent agreement with computer simulations. These simulations provide additional evidence for logarithmic terms in the density expansion of the diffusion coefficient.

  11. The Production of Polycyclic Aromatic Hydrocarbon Anions in Inert Gas Matrices Doped with Alkali Metals. Electronic Absorption Spectra of the Pentacene Anion (C22H14(-))

    NASA Technical Reports Server (NTRS)

    Halasinski, Thomas M.; Hudgins, Douglas M.; Salama, Farid; Allamandola, Louis J.; Mead, Susan (Technical Monitor)

    1999-01-01

    The absorption spectra of pentacene (C22H14) and its radical cation (C22H14(+)) and anion (C22H14(-)) isolated in inert-gas matrices of Ne, Ar, and Kr are reported from the ultraviolet to the near-infrared. The associated vibronic band systems and their spectroscopic assignments are discussed together with the physical and chemical conditions governing ion (and counterion) production in the solid matrix. In particular, the formation of isolated pentacene anions is found to be optimized in matrices doped with alkali metal (Na and K).

  12. Analyzing the safety impact of containment inerting at Vermont Yankee

    E-print Network

    Heising, Carolyn D. (Carolyn DeLane), 1952-

    1980-01-01

    Post-accident hydrogen generation in BWR containments is analyzed as a function of engineered hydrogen control system, assumed either nitrogen inerting or air dilution. Fault tree analysis was applied to assess the failure ...

  13. Density functional theory of gas-liquid phase separation in dilute binary mixtures

    E-print Network

    Ryuichi Okamoto; Akira Onuki

    2015-12-29

    We examine statics and dynamics of phase-separated states of dilute binary mixtures using density functional theory. In our systems, the difference in the salvation chemical potential $\\Delta\\mu_s$ between liquid and gas is considerably larger than the thermal energy $k_BT$ for each solute particle and the attractive interaction among the solute particles is weaker than that among the solvent particles. In these conditions, the saturated vapor pressure increases by an amount equal to the solute density in liquid multiplied by the large factor $k_BT \\exp(\\Delta\\mu_s/k_BT)$. As a result, phase separation is induced at low solute densities in liquid and the new phase remains in gaseous states, while the liquid pressure is outside the coexistence curve of the solvent. This explains the widely observed formation of stable nanobubbles in ambient water with a dissolved gas. We calculate the density and stress profiles across planar and spherical interfaces, where the surface tension decreases with increasing the interfacial solute adsorption. We realize stable solute-rich bubbles with radius about 30 nm, which minimize the free energy functional. We then study dynamics around such a bubble after a decompression of the surrounding liquid, where the bubble undergoes a damped oscillation. In addition, we present some exact and approximate expressions for the surface tension and the interfacial stress tensor.

  14. Bose-Einstein Condensation in a Dilute Gas; the First 70 Years and Some Recent Experiments

    NASA Astrophysics Data System (ADS)

    Cornell, E. A.; Wieman, C. E.

    Bose-Einstein condensation, or BEC, has a long and rich history dating from the early 1920s. In this article we will trace briefly over this history and some of the developments in physics that made possible our successful pursuit of BEC in a gas. We will then discuss what was involved in this quest. In this discussion we will go beyond the usual technical description to try and address certain questions that we now hear frequently, but are not covered in our past research papers. These are questions along the lines of ``How did you get the idea and decide to pursue it? Did you know it was going to work? How long did it take you and why?'' We will review some of our favorites from among the experiments we have carried out with BEC. There will then be a brief encore on why we are optimistic that BEC can be created with nearly any species of magnetically trappable atom. Throughout this article we will try to explain what makes BEC in a dilute gas so interesting, unique, and experimentally challenging. This article is our ``Nobel Lecture'' and as such takes a relatively personal approach to the story of the development of experimental Bose-Einstein condensation. For a somewhat more scholarly treatment of the history, the interested reader is referred to E. A. Cornell, J. R. Ensher and C. E. Wieman, ``Experiments in dilute atomic Bose-Einstein condensation in Bose-Einstein Condensation in Atomic Gases, Proceedings of the International School of Physics ``Enrico Fermi'' Course CXL'' (M. Inguscio, S. Stringari and C. E. Wieman, Eds., Italian Physical Society, 1999), pp. 15-66, which is also available as cond-mat/9903109. For a reasonably complete technical review of the three years of explosive progress that immediately followed the first observation of BEC, we recommend reading the above article in combination with the corresponding review from Ketterle, cond-mat/9904034.

  15. A simple thermodynamic model of diluted hydrogen gas/plasma for CFD applications

    NASA Astrophysics Data System (ADS)

    Quartapelle, L.; Muzzio, A.

    2015-06-01

    This work describes a simple thermodynamic model of the hydrogen gas at low densities and for temperatures going from those involving quantum rotations of ortho- and para-hydrogen up to the fully ionized state. The closed-form energy levels of Morse rotating oscillator given [D.C. Harris, M.D. Bertolucci, Symmetry and Spectroscopy (Dover, New York, 1989)] (but not those in Morse's original paper) are shown to provide an internal partition function of H2 that is a sufficiently accurate representation of that exploiting the state-of-the-art spectrum of roto-vibrational levels calculated by Pachucki and Komasa [K. Pachucki, J. Komasa, J. Chem. Phys. 130, 164113 (2009)]. A system of two coupled quadratic equations for molecular dissociation and atomic ionization at thermodynamical and chemical equilibrium is derived according to the statistical mechanics by assuming that the system is an ideal mixture containing molecules, neutral atoms and noninteracting protons and electrons. The system of two equations reduces to a single quartic equation for the ionization unknown, with the coefficients dependent on the temperature and the specific volume. Explicit relations for specific energy and entropy of the hydrogen ideal gas/plasma model are derived. These fully compatible equations of state provide a complete thermodynamic description of the system, uniformly valid from low temperatures up to a fully ionized state, with electrons and ions relaxed to one and the same temperature. The comparison with results of other models developed in the framework of the physical and chemical pictures shows that the proposed elementary model is adequate for computational fluid dynamics purposes, in applications with the hydrogen gas under diluted conditions and when the dissociation and ionization can be assumed at thermodynamical and chemical equilibrium.

  16. Dispersion coefficients for the interactions of the alkali-metal and alkaline-earth-metal ions and inert-gas atoms with a graphene layer

    NASA Astrophysics Data System (ADS)

    Kaur, Kiranpreet; Arora, Bindiya; Sahoo, B. K.

    2015-09-01

    Largely motivated by a number of applications, the van der Waals dispersion coefficients C3 of the alkali-metal ions Li+,Na+,K+, and Rb+, the alkaline-earth-metal ions Ca+,Sr+,Ba+, and Ra+, and the inert-gas atoms He, Ne, Ar, and Kr with a graphene layer are determined precisely within the framework of the Dirac model. For these calculations, we evaluate the dynamic polarizabilities of the above atomic systems very accurately by evaluating the transition matrix elements employing relativistic many-body methods and using the experimental values of the excitation energies. The dispersion coefficients are given as functions of the separation distance of an atomic system from the graphene layer and the ambiance temperature during the interactions. For easy extraction of these coefficients, we give a logistic fit to the functional forms of the dispersion coefficients in terms of the separation distances at room temperature.

  17. A new technique for the strengthening of aluminum tungsten inert gas weld metals: using carbon nanotube/aluminum composite as a filler metal.

    PubMed

    Fattahi, M; Nabhani, N; Rashidkhani, E; Fattahi, Y; Akhavan, S; Arabian, N

    2013-01-01

    The effect of multi-walled carbon nanotube (MWCNT) on the mechanical properties of aluminum multipass weld metal prepared by the tungsten inert gas (TIG) welding process was investigated. High energy ball milling was used to disperse MWCNT in the aluminum powder. Carbon nanotube/aluminum composite filler metal was fabricated for the first time by hot extrusion of ball-milled powders. After welding, the tensile strength, microhardness and MWCNT distribution in the weld metal were investigated. The test results showed that the tensile strength and microhardness of weld metal was greatly increased when using the filler metal containing 1.5 wt.% MWCNT. Therefore, according to the results presented in this paper, it can be concluded that the filler metal containing MWCNT can serve as a super filler metal to improve the mechanical properties of TIG welds of Al and its alloys. PMID:23948441

  18. Dispersion coefficients for the interactions of the alkali and alkaline-earth ions and inert gas atoms with a graphene layer

    E-print Network

    Kaur, Kiranpreet; Sahoo, B K

    2015-01-01

    Largely motivated by a number of applications, the van der Waals dispersion coefficients ($C_3$s) of the alkali ions (Li$^+$, Na$^+$, K$^+$ and Rb$^+$), the alkaline-earth ions (Ca$^+$, Sr$^+$, Ba$^+$ and Ra$^+$) and the inert gas atoms (He, Ne, Ar and Kr) with a graphene layer are determined precisely within the framework of Dirac model. For these calculations, we have evaluated the dynamic polarizabilities of the above atomic systems very accurately by evaluating the transition matrix elements employing relativistic many-body methods and using the experimental values of the excitation energies. The dispersion coefficients are, finally, given as functions of the separation distance of an atomic system from the graphene layer and the ambiance temperature during the interactions. For easy extraction of these coefficients, we give a logistic fit to the functional forms of the dispersion coefficients in terms of the separation distances at the room temperature.

  19. [Determination of endogenous agmatine in rat plasma by isotope dilution-gas chromatography-mass spectrometry].

    PubMed

    Qiu, Zhongli; Lin, Ying; Xiong, Zhili; Xie, Jianwei

    2014-07-01

    A method for the determination of endogenous agmatine in rat plasma was developed by isotope dilution-gas chromatography-negative chemical ionization mass spectrometry (GC-NCI/MS). The plasma samples were analyzed after protein precipitation, evaporation, derivatization by hexafluoroacetone (HFAA), and clean-up on a Florisil SPE column. The GC-MS analysis utilized stable isotope d8-agmatine as internal standard. The samples after treatme were tested by negative chemical ionization with selected ion monitoring (SIM) which was set at m/z 492 (molecular ion of agmatine) and m/z 500 (molecular ion of internal standard). The limit of detection (LOD) of agmatine standard solution was 0.005 7 ng/mL. The calibration curve of the agmatine spiked in rat plasma showed a good linear relationship at the range of 1.14-57.0 ng/mL (r = 0.997). The recoveries of agmatine spiked in rat plasma ranged from 92.3% to 109.8%. Inter-day and intra-day precisions were less than 15%. The average concentration level of agmatine in rat plasma was (22 +/- 9) ng/mL, and there was no significant difference between male and female SD rats (p > 0.05). The method is high sensitive and specific, and can be used for the determination of endogenous agmatine in plasma. It provides a strong support for the subsequent research of agmatine. PMID:25255573

  20. Influence of a magnetic field on the viscosity of a dilute gas consisting of linear molecules.

    PubMed

    Hellmann, Robert; Vesovic, Velisa

    2015-12-01

    The viscomagnetic effect for two linear molecules, N2 and CO2, has been calculated in the dilute-gas limit directly from the most accurate ab initio intermolecular potential energy surfaces presently available. The calculations were performed by means of the classical trajectory method in the temperature range from 70 K to 3000 K for N2 and 100 K to 2000 K for CO2, and agreement with the available experimental data is exceptionally good. Above room temperature, where no experimental data are available, the calculations provide the first quantitative information on the magnitude and the behavior of the viscomagnetic effect for these gases. In the presence of a magnetic field, the viscosities of nitrogen and carbon dioxide decrease by at most 0.3% and 0.7%, respectively. The results demonstrate that the viscomagnetic effect is dominated by the contribution of the jj¯ polarization at all temperatures, which shows that the alignment of the rotational axes of the molecules in the presence of a magnetic field is primarily responsible for the viscomagnetic effect. PMID:26646878

  1. Glass transition of adsorbed stereoregular PPMA by inverse gas chromatography at infinite dilution

    NASA Astrophysics Data System (ADS)

    Hamieh, T.; Rezzaki, M.; Grohens, Y.; Schultz, J.

    1998-10-01

    In this paper, we used inverse gas chromatography (IGC) at infinite dilution that proved to be a powerful technique to determine glass transition and other transitions of PMMA adsorbed on ?-alumina. We highlighted the glass transition temperature of the system PMMA/?-Al2O3 with defined polymer tacticity at various covered surface fractions. Thus, the Tg of the adsorbed isotactic PMMA increases strongly as compared to the bulk value. The study of the physical chemical properties of PMMA/?-alumina revealed an important difference in the acidic and basic behaviour, in Lewis terms, of aluminium oxide covered by various concentrations of PMMA. It appears that there is a stabilisation of the physical chemical properties of PMMA/?-Al2O3 for a surface coverage above 50%. This study also highlighted an important effect of the tacticity of the polymer on the acid-base character of the system PMMA/Al2O3. Dans cet article, nous montrons que la chromatographie gazeuse inverse (CGI) à dilution infinie se révèle être une technique très intéressante pour la détermination de la transition vitreuse de polymères stéréoréguliers adsorbés sur des substrats solides tels que l'alumine. Nous avons mis en évidence des transitions attribuées aux phénomènes de relaxation béta, transition vitreuse et autres transitions des systèmes PMMA/Al2O3 de tacticité définie à différents taux de recouvrement. Ainsi, la Tg du PMMA isotactique adsorbé augmente de façon significative par rapport a celle du polymère massique. L'étude des propriétés physico-chimiques du système PMMA/Al2O3, révèle une différence importante dans le comportement acido-basique, au sens de Lewis, de l'alumine pour de taux de recouvrement en PMMA variables. Il apparaît qu'il y a stabilisation des propriétés physico-chimiques de PMMA/Al2O3 pour un taux de recouvrement en PMMA supérieur à 50 %. Cette étude a montré également une influence importante de la tacticité du polymère sur le caractère acido-basique du couple PMMA/Al2O3.

  2. Characterisation of the surface thermodynamic properties of cement components by inverse gas chromatography at infinite dilution

    SciTech Connect

    Perruchot, Christian; Chehimi, Mohamed M.; Vaulay, Marie-Josephe; Benzarti, Karim . E-mail: benzarti@lcpc.fr

    2006-02-15

    The surface thermodynamic properties of three main inorganic compounds formed during hydration of Portland cement: calcium hydroxide (Ca(OH){sub 2}), ettringite (3CaO.Al{sub 2}O{sub 3}.3CaSO{sub 4}.32H{sub 2}O) and calcium-silicate-hydrates (C-S-H), respectively, and one mineral filler: calcium carbonate (CaCO{sub 3}), have been characterised by inverse gas chromatography at infinite dilution (IGC-ID) at 35 deg. C. The thermodynamic properties have been investigated using a wide range of non-polar (n-alkane series), Lewis acidic (CH{sub 2}Cl{sub 2} and CHCl{sub 3}), Lewis basic (diethyl ether) and aromatic (benzene) and n-alkene series molecular probes, respectively. The tested samples are fairly high surface energy materials as judged by the high dispersive contribution to the total surface energy (the dispersive components {gamma} {sub s} {sup d} range from 45.6 up to 236.2 mJ m{sup -2} at 35 deg. C) and exhibit amphoteric properties, with a predominant acidic character. In the case of hydrated components (i.e. ettringite and C-S-H), the surface thermodynamic properties have been determined at various temperatures (from 35 up to 120 deg. C) in order to examine the influence of the water content. The changes of both dispersive and specific components clearly demonstrate that the material surface properties are activated with temperature. The changes in the acid-base properties are correlated with the extent of the overall water loss induced by the thermal treatment as demonstrated by thermogravimetric analysis (TGA). The elemental surface composition of these compounds has been determined by X-ray photoelectron spectroscopy (XPS)

  3. Keto-enol tautomers of 1,2-cyclohexanedione in solid, liquid, vapour and a cold inert gas matrix: Infrared spectroscopy and quantum chemistry calculation

    NASA Astrophysics Data System (ADS)

    Samanta, Amit K.; Pandey, Prasenjit; Bandyopadhyay, Biman; Chakraborty, Tapas

    2010-01-01

    Fourier transform infrared (FTIR) spectroscopy of 1,2-cyclohexanedione (CHD) has been studied with the neat sample, low-pressure vapour, CCl 4 solution and in cold N 2 matrix. The matrix-isolation spectrum has been assigned exclusively in terms of transitions of the enol tautomer, that is stabilized by an intramolecular O⋯H sbnd O hydrogen bond (HB). The vibrational fundamentals of the diketo tautomer appear weakly in the spectra of CCl 4 solution and vapour. On the other hand, the spectrum of the neat sample shows significant population of the diketo tautomer. Thus the intermolecular interactions, which are dominant in the neat sample, stabilize the diketo form. The predictions of electronic structure calculations by B3LYP/6-311++G(d,p) and MP2/cc-pVTZ methods are found to be consistent with the measured tautomeric distribution in the cold inert gas matrix. The larger dipole moment of the diketo tautomer (5.61 D) compared to enol form (3.60 D) is proposed to be responsible for stability of the former in the neat sample. The vibrational fundamentals predicted by anharmonic calculation at B3LYP/6-311++G(d,p) level display excellent agreement with measured frequencies. The proposed assignments are further corroborated by noting the deuterium isotopic shifts of different bands and their predicted shifts by the same theoretical methods.

  4. Effects of CaF2 Coating on the Microstructures and Mechanical Properties of Tungsten Inert Gas Welded AZ31 Magnesium Alloy Joints

    NASA Astrophysics Data System (ADS)

    Shen, Jun; Wang, Linzhi; Peng, Dong; Wang, Dan

    2012-11-01

    The effects of CaF2 coating on the macromorphologies of the welded seams were studied by morphological analysis. Microstructures and mechanical properties of butt joints welded with different amounts of CaF2 coatings were investigated using optical microscopy and tensile tests. The welding defects formed in the welded seams and the fracture surfaces were analyzed by scanning electron microscopy. An increase in the amount of CaF2 coating deteriorated the appearances of the welded seams but it improved the weld penetration depth and the depth/width ( D/ W) ratio of the tungsten inert gas (TIG) welded joints. The ?-Mg grains and Mg17(Al,Zn)12 intermetallic compound (IMC) were coarser in the case of a higher amount of CaF2 coating. The increase in the amount of CaF2 coating reduced the porosities and total length of solidification cracks in the fusion zone (FZ). The ultimate tensile strength (UTS) value and elongation increased at first and then decreased sharply.

  5. Tungsten Inert Gas and Friction Stir Welding Characteristics of 4-mm-Thick 2219-T87 Plates at Room Temperature and -196 °C

    NASA Astrophysics Data System (ADS)

    Lei, Xuefeng; Deng, Ying; Yin, Zhimin; Xu, Guofu

    2014-06-01

    2219-T87 aluminum alloy is widely used for fabricating liquid rocket propellant storage tank, due to its admirable cryogenic property. Welding is the dominant joining method in the manufacturing process of aerospace components. In this study, the tungsten inert gas welding and friction stir welding (FSW) characteristics of 4-mm-thick 2219-T87 alloy plate at room temperature (25 °C) and deep cryogenic temperature (-196 °C) were investigated by property measurements and microscopy methods. The studied 2219 base alloy exhibits a low strength plane anisotropy and excellent room temperature and cryogenic mechanical properties. The ultimate tensile strength values of TIG and FSW welding joints can reach 265 and 353 MPa at room temperature, and 342 and 438 MPa at -196 °C, respectively. The base metal consists of elongated deformed grains and many nano-scaled ? (Al2Cu) aging precipitates. Fusion zone and heat-affected zone (HAZ) of the TIG joint are characterized by coarsening dendritic grains and equiaxed recrystallized grains, respectively. The FSW-welded joint consists of the weld nugget zone, thermo-mechanically affected zone (TMAZ), and HAZ. In the weld nugget zone, a micro-scaled sub-grain structure is the main microstructure characteristic. The TMAZ and HAZ are both characterized by coarsened aging precipitates and elongated deformed grains. The excellent FSW welding properties are attributed to the preservation of the working structures and homogenous chemical compositions.

  6. The Role of Spraying Parameters and Inert Gas Shrouding in Hybrid Water-Argon Plasma Spraying of Tungsten and Copper for Nuclear Fusion Applications

    NASA Astrophysics Data System (ADS)

    Mat?jí?ek, J.; Kavka, T.; Bertolissi, G.; Ctibor, P.; Vilémová, M.; Mušálek, R.; Nevrlá, B.

    2013-06-01

    Tungsten-based coatings have potential application in the plasma-facing components in future nuclear fusion reactors. By the combination of refractory tungsten with highly thermal conducting copper, or steel as a construction material, functionally graded coatings can be easily obtained by plasma spraying, and may result in the development of a material with favorable properties. During plasma spraying of these materials in the open atmosphere, oxidation is an important issue, which could have adverse effects on their properties. Among the means to control it is the application of inert gas shrouding, which forms the subject of this study and represents a lower-cost alternative to vacuum or low-pressure plasma spraying, potentially applicable also for spraying of large surfaces or spacious components. It is a continuation of recent studies focused on the effects of various parameters of the hybrid water-argon torch on the in-flight behavior of copper and tungsten powders and the resultant coatings. In the current study, argon shrouding with various configurations of the shroud was applied. The effects of torch parameters, such as power and argon flow rate, and powder morphology were also investigated. Their influence on the particle in-flight behavior as well as the structure, composition and properties of the coatings were quantified. With the help of auxiliary calculations, the mass changes of the powder particles, associated with oxidation and evaporation, were assessed.

  7. Methanol Droplet Combustion in Oxygen-Inert Environments in Microgravity

    NASA Technical Reports Server (NTRS)

    Nayagam, Vedha; Dietrich, Daniel L.; Hicks, Michael C.; Williams, Forman A.

    2013-01-01

    The Flame Extinguishment (FLEX) experiment that is currently underway in the Combustion Integrated Rack facility onboard the International Space Station is aimed at understanding the effects of inert diluents on the flammability of condensed phase fuels. To this end, droplets of various fuels, including alkanes and alcohols, are burned in a quiescent microgravity environment with varying amounts of oxygen and inert diluents to determine the limiting oxygen index (LOI) for these fuels. In this study we report experimental observations of methanol droplets burning in oxygen-nitrogen-carbon dioxide and oxygen-nitrogen-helium gas mixtures at 0.7 and 1 atmospheric pressures. The initial droplet size varied between approximately 1.5 mm and 4 mm to capture both diffusive extinction brought about by insufficient residence time at the flame and radiative extinction caused by excessive heat loss from the flame zone. The ambient oxygen concentration varied from a high value of 30% by volume to as low as 12%, approaching the limiting oxygen index for the fuel. The inert dilution by carbon dioxide and helium varied over a range of 0% to 70% by volume. In these experiments, both freely floated and tethered droplets were ignited using symmetrically opposed hot-wire igniters and the burning histories were recorded onboard using digital cameras, downlinked later to the ground for analysis. The digital images yielded droplet and flame diameters as functions of time and subsequently droplet burning rate, flame standoff ratio, and initial and extinction droplet diameters. Simplified theoretical models correlate the measured burning rate constant and the flame standoff ratio reasonably well. An activation energy asymptotic theory accounting for time-dependent water dissolution or evaporation from the droplet is shown to predict the measured diffusive extinction conditions well. The experiments also show that the limiting oxygen index for methanol in these diluent gases is around 12% to 13% oxygen by volume.

  8. EFFICIENCY OF GAS-WALL REACTIONS IN A CYLINDRICAL FLOW REACTOR

    EPA Science Inventory

    Expressions are given for the concentration of a dilute reactive gas mixed with an inert carrier gas as a function of the radial and longitudinal distances in a cylindrical reactor and the reaction efficiency. The reaction efficiency is defined as the fraction of gas-wall collisi...

  9. Constraining the volatility distribution and gas-particle partitioning of combustion aerosols using isothermal dilution and thermodenuder measurements.

    PubMed

    Grieshop, Andrew P; Miracolo, Marissa A; Donahue, Niel M; Robinson, Allen L

    2009-07-01

    The gas-particle partitioning of primary organic aerosol (POA) emissions from a diesel engine and the combustion of hard- and soft-woods in a stove was investigated by isothermally diluting them in a smog chamber or by passing them through a thermodenuder and measuring the extent of evaporation. The experiments were conducted at atmospherically relevant conditions: low concentrations and small temperature perturbations. The partitioning of the POA emissions from both sources varied continuously with changing concentration and temperature. Although the POA emissions are semivolatile, they do not completely evaporate at typical atmospheric conditions. The overall partitioning characteristics of diesel and wood smoke POA are similar, with wood smoke being somewhat less volatile than the diesel exhaust. The gas-particle partitioning of aerosols formed from flash-vaporized engine lubricating oil was also studied; diesel POA is somewhat more volatile than the oil aerosol. The experimental data from the dilution- and thermodenuder-based techniques were fit using absorptive partitioning theory to derive a volatility distribution of the POA emissions from each source. These distributions are suitable for use in chemical transport models that simulate POA concentrations. PMID:19673261

  10. Approaches of aroma extraction dilution analysis (AEDA) for headspace solid phase microextraction and gas chromatography-olfactometry (HS-SPME-GC-O): Altering sample amount, diluting the sample or adjusting split ratio?

    PubMed

    Feng, Yunzi; Cai, Yu; Sun-Waterhouse, Dongxiao; Cui, Chun; Su, Guowan; Lin, Lianzhu; Zhao, Mouming

    2015-11-15

    Aroma extract dilution analysis (AEDA) is widely used for the screening of aroma-active compounds in gas chromatography-olfactometry (GC-O). In this study, three aroma dilution methods, (I) using different test sample volumes, (II) diluting samples, and (III) adjusting the GC injector split ratio, were compared for the analysis of volatiles by using HS-SPME-AEDA. Results showed that adjusting the GC injector split ratio (III) was the most desirable approach, based on the linearity relationships between Ln (normalised peak area) and Ln (normalised flavour dilution factors). Thereafter this dilution method was applied in the analysis of aroma-active compounds in Japanese soy sauce and 36 key odorants were found in this study. The most intense aroma-active components in Japanese soy sauce were: ethyl 2-methylpropanoate, ethyl 2-methylbutanoate, ethyl 3-methylbutanoate, ethyl 4-methylpentanoate, 3-(methylthio)propanal, 1-octen-3-ol, 2-methoxyphenol, 4-ethyl-2-methoxyphenol, 2-methoxy-4-vinylphenol, 2-phenylethanol, and 4-hydroxy-5-ethyl-2-methyl-3(2H)-furanone. PMID:25976996

  11. Inert gas ion thruster development

    NASA Technical Reports Server (NTRS)

    Ramsey, W. D.

    1980-01-01

    Two 12 cm magneto-electrostatic containment (MESC) ion thrusters were performance mapped with argon and xenon. The first, hexagonal, thruster produced optimized performance of 48.5to 79 percent argon mass utilization efficiencies at discharge energies of 240 to 425 eV/ion, respectively, Xenon mass utilization efficiencies of 78 to 95 percent were observed at discharge energies of 220 to 290 eV/ion with the same optimized hexagonal thruster. Changes to the cathode baffle reduced the discharge anode potential during xenon operation from approximately 40 volts to about 30 volts. Preliminary tests conducted with the second, hemispherical, MESC thruster showed a nonuniform anode magnetic field adversely affected thruster performance. This performance degradation was partially overcome by changes in the boundary anode placement. Conclusions drawn the hemispherical thruster tests gave insights into the plasma processes in the MESC discharge that will aid in the design of future thrusters.

  12. Inert Anode Report

    SciTech Connect

    none,

    1999-07-01

    This ASME report provides a broad assessment of open literature and patents that exist in the area of inert anodes and their related cathode systems and cell designs, technologies that are relevant for the advanced smelting of aluminum. The report also discusses the opportunities, barriers, and issues associated with these technologies from a technical, environmental, and economic viewpoint.

  13. Origins of Inert Higgs Doublets

    E-print Network

    Thomas W. Kephart; Tzu-Chiang Yuan

    2015-08-14

    We consider beyond the standard model embedding of inert Higgs doublet fields. We argue that inert Higgs doublets can arise naturally in grand unified theories where the necessary associated $Z_2$ symmetry can occur automatically. Several examples are discussed.

  14. 46 CFR 154.1848 - Inerting.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... oxygen concentration is 8 percent or less by volume when flammable cargoes are carried; (2) Hold and... tanks are to be filled with a flammable cargo, air is purged from the tank by inert gas until the oxygen concentration in the tank is 8 percent or less by volume before cargo liquid or vapor is introduced. (b)...

  15. 46 CFR 154.1848 - Inerting.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... oxygen concentration is 8 percent or less by volume when flammable cargoes are carried; (2) Hold and... tanks are to be filled with a flammable cargo, air is purged from the tank by inert gas until the oxygen concentration in the tank is 8 percent or less by volume before cargo liquid or vapor is introduced. (b)...

  16. 46 CFR 154.1848 - Inerting.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... oxygen concentration is 8 percent or less by volume when flammable cargoes are carried; (2) Hold and... tanks are to be filled with a flammable cargo, air is purged from the tank by inert gas until the oxygen concentration in the tank is 8 percent or less by volume before cargo liquid or vapor is introduced. (b)...

  17. 46 CFR 154.1848 - Inerting.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... oxygen concentration is 8 percent or less by volume when flammable cargoes are carried; (2) Hold and... tanks are to be filled with a flammable cargo, air is purged from the tank by inert gas until the oxygen concentration in the tank is 8 percent or less by volume before cargo liquid or vapor is introduced. (b)...

  18. Method of producing hydrogen, and rendering a contaminated biomass inert

    DOEpatents

    Bingham, Dennis N. (Idaho Falls, ID) [Idaho Falls, ID; Klingler, Kerry M. (Idaho Falls, ID) [Idaho Falls, ID; Wilding, Bruce M. (Idaho Falls, ID) [Idaho Falls, ID

    2010-02-23

    A method for rendering a contaminated biomass inert includes providing a first composition, providing a second composition, reacting the first and second compositions together to form an alkaline hydroxide, providing a contaminated biomass feedstock and reacting the alkaline hydroxide with the contaminated biomass feedstock to render the contaminated biomass feedstock inert and further producing hydrogen gas, and a byproduct that includes the first composition.

  19. Stable isotope dilution gas chromatography-mass spectrometry for quantification of thymoquinone in black cumin seed oil.

    PubMed

    Johnson-Ajinwo, Okiemute Rosa; Li, Wen-Wu

    2014-06-18

    Black cumin seed (Nigella sativa L.) is a widely used spice and herb, where thymoquinone (2-isopropyl-5-methyl-1,4-benzoquinone) is the major bioactive compound. Here, a stable isotope dilution (SID) gas chromatography-mass spectrometry (GC-MS) technique was developed for the quantification of thymoquinone. A doubly deuterated thymoquinone ([(2)H2]-thymoquinone) was synthesized for the first time with more than 93% deuteration degree shown by mass spectrometry and proton nuclear magnetic resonance ((1)H NMR). This compound was used as an internal standard for the quantification of thymoquinone using a SID GC-MS method. The validation experiment showed a recovery rate of 99.1 ± 1.1% relative standard deviation (RSD). Standard addition and external calibration methods have also been used to quantify thymoquinone, which cross-validated the developed stable isotope dilution assay (SIDA). In comparison to external calibration and standard addition methods, the SIDA method is robust and accurate. The concentration of thymoquinone in five marketed black cumin seed oils ranged between 3.34 and 10.8 mg/mL by use of SID GC-MS. PMID:24871868

  20. Activity coefficients at infinite dilution of organic compounds in 1-(meth)acryloyloxyalkyl-3-methylimidazolium bromide using inverse gas chromatography.

    PubMed

    Mutelet, Fabrice; Jaubert, Jean-Noël; Rogalski, Marek; Harmand, Julie; Sindt, Michèle; Mieloszynski, Jean-Luc

    2008-03-27

    Activity coefficients at infinite dilution, gammainfinity, of organic compounds in two new room-temperature ionic liquids (n-methacryloyloxyhexyl-N-methylimidazolium bromide (C10H17O2MIM)(Br) at 313.15 and 323.15 K and n-acryloyloxypropyl-N-methylimidazolium bromide(C6H11O2MIM)(Br)) were determined using inverse gas chromatography. Phase loading studies of the net retention volume per gram of packing as a function of the percent phase loading were used to estimate the influence of concurrent retention mechanisms on the accuracy of activity coefficients at infinite dilution of solutes in both ionic liquids. It was found that most of the solutes were retained largely by partition with a small contribution from adsorption and that n-alkanes were retained predominantly by interfacial adsorption on ionic liquids studied in this work. The solvation characteristics of the two ionic liquids were evaluated using the Abraham solvation parameter model. PMID:18318530

  1. Inert gases in Sea of Fertility regolith

    NASA Technical Reports Server (NTRS)

    Vinogradov, A. P.; Zadorozhnyy, I. K.

    1974-01-01

    The content and isotopic composition were studied of inert gases -- He, Ne, Ar, Kr, and Xe -- in samples of lunar regolith returned by the Luna 16 automatic station. The samples were taken from depths of about 12 and 30 cm. The high concentrations of inert gases exceed by several orders their concentrations observed in ordinary stony meteorites. The gases in lunar regolith were a complex mixture of gases of different origins: Solar, cosmogenic, radiogenic, and so on. Solar wind gases predominated, distributed in the thin surficial layer of the regolith grains. The concentrations of these gases in the surficial layer is several cubic centimeters per gram. The isotopic composition of the inert gases of solar origin approaches their composition measured in gas-rich meteorites.

  2. Efficient gas-separation process to upgrade dilute methane stream for use as fuel

    DOEpatents

    Wijmans, Johannes G. (Menlo Park, CA); Merkel, Timothy C. (Menlo Park, CA); Lin, Haiqing (Mountain View, CA); Thompson, Scott (Brecksville, OH); Daniels, Ramin (San Jose, CA)

    2012-03-06

    A membrane-based gas separation process for treating gas streams that contain methane in low concentrations. The invention involves flowing the stream to be treated across the feed side of a membrane and flowing a sweep gas stream, usually air, across the permeate side. Carbon dioxide permeates the membrane preferentially and is picked up in the sweep air stream on the permeate side; oxygen permeates in the other direction and is picked up in the methane-containing stream. The resulting residue stream is enriched in methane as well as oxygen and has an EMC value enabling it to be either flared or combusted by mixing with ordinary air.

  3. Laboratory Formation of Carbonaceous Particles in Dilute Gas Mixtures of Organic Molecules

    NASA Astrophysics Data System (ADS)

    Cody, R. J.

    1998-12-01

    Particles of various organic compositions have been observed in the atmospheres of the outer planets, their satellites, and comets. Infrared (IR) spectral features reveal the presence of these particles in the outer planetary system, especially Titan. ``CHON" particles in the coma of Comet Halley were analyzed chemically by the Giotto spacecraft. Organic molecules in the atmospheres of these bodies are present in gas concentrations of parts per million by volume (ppmv). A recently developed laboratory technique can generate small carbonaceous particles from gas mixtures containing organic molecules in the ppmv range either in the presence or absence of water. The particles are formed by the photolysis of a gas mixture of ppmv of small organic molecules (C2 to C8) in a carrier gas at atmospheric pressure. The photolysis source is an excimer laser at 193 nm. Since the flow area of the gas is larger than that of the laser beam, a mixture of irradiated and unirradiated gases are producing the particles. A visible laser (He-Ne at 633 nm) is used to monitor the particles by scattering. Nitrogen, Argon, or Helium are the carrier gases in slowly flowing gas streams. The gas flows counter to the laser beam propagation direction. Since the laser beam penetrates 10-40 cm of the 150 cm long flow tube, a particle formation front is established, and samples are collected upstream of this front. The particles are collected on ZnS or ZnSe substrates, and their IR spectra from 2.5-14 (or 20) microns is measured with an FTIR instrument. The samples are then heated at low temperatures, and the IR spectra are remeasured. Since the most extensive set of experiments has consisted of photolyzing a gas mixture of several ppmv of small aromatic molecules in each of the carrier gases with saturated water vapor, these conditions are more representative of cometary atmospheres. Aromatic gas mixtures without water have been photolyzed to be more representative of outer planetary atmospheres. Comparisons are made between the IR spectra of the particles formed from the two types of gas mixtures. This research is being supported by the Laboratory Astrophysics Program of NASA Headquarters.

  4. Physical and Mathematical Modeling of Inert Gas-Shrouded Ladle Nozzles and Their Role on Slag Behavior and Fluid Flow Patterns in a Delta-Shaped, Four-Strand Tundish

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Kinnor; Hasan, Mainul; Isac, Mihaiela; Guthrie, Roderick I. L.

    2010-02-01

    Inert gas shrouding practices were simulated using a full-scale, four-strand water model of a 12-tone, delta-shaped tundish. Compressed air was aspirated into the ladle shroud to model volumetric flow rates that range between 2 and 10 pct of steel entry flows. Bubble trajectories, slag layer movements, and flow fields, were visualized. Flow fields were visualized using particle image velocimetry (PIV). A numerical model also was developed using discrete phase modeling (DPM) along with the standard k-? turbulence model with two-way turbulence coupling. Predicted flow fields and bubble trajectories corresponded with the water model experiments.

  5. An improved multiscale model for dilute turbulent gas particle flows based on the equilibration of energy concept

    SciTech Connect

    Xu, Ying

    2005-05-01

    Many particle-laden flows in engineering applications involve turbulent gas flows. Modeling multiphase turbulent flows is an important research topic with applications in fluidized beds and particle conveying. A predictive multiphase turbulence model can help CFD codes to be more useful for engineering applications, such as the scale-up in the design of circulating fluidized combustor and coal gasifications. In engineering applications, the particle volume fraction can vary from dilute (<10{sup -4}) to dense ({approx} 50%). It is reasonable to expect that multiphase turbulence models should at least satisfy some basic modeling and performance criteria and give reasonable predictions for the canonical problems in dilute particle-laden turbulent flows. In this research, a comparative assessment of predictions from Simonin and Ahmadi's turbulence models is performed with direct numerical simulation (DNS) for two canonical problems in particle-laden turbulent flows. Based on the comparative assessment, some criteria and the areas for model improvement are identified: (1) model for interphase TKE transfer, especially the time scale of interphase TKE transfer, and (2) correct prediction of TKE evolution with variation of particle Stokes number. Some deficiencies that are identified in the Simonin and Ahmadi models, limit the applicability. A new multiphase turbulence model, the Equilibration of Energy Model (EEM), is proposed in this work. In EEM, a multiscale interaction time scale is proposed to account for the interaction of a particle with a range of eddy sizes. EEM shows good agreement with the DNS results for particle-laden isotropic turbulence. For particle-laden homogeneous shear flows, model predictions from EEM can be further improved if the dissipation rate in fluid phase is modeled with more accuracy.

  6. The dilute Fermi gas is the most "perfect fluid" in Nature

    E-print Network

    Gabriel Wlaz?owski; Wei Quan; Aurel Bulgac

    2015-07-03

    We present an ab initio calculation of the shear viscosity as a function of interaction strength in a two-component unpolarized Fermi gas near the unitary limit, within a finite temperature quantum Monte Carlo (QMC) framework and using the Kubo linear-response formalism. The shear viscosity decreases as we tune the interaction strength $1/ak_F$ from the Bardeen-Cooper-Schrieffer (BCS) side of the Feshbach resonance towards Bose-Einstein condensation (BEC) limit and it acquires the smallest value for $1/ak_F\\approx0.4$, with a minimum value of $\\left . \\frac{\\eta}{s}\\right |_{min} \\approx 0.2 \\frac{\\hbar}{k_B}$, which is about twice as small than the value reported for experiments in quark-gluon plasma $\\left . \\frac{\\eta}{s}\\right |_{QGP} \\lesssim 0.4\\frac{\\hbar}{k_B}$. The Fermi gas near unitarity thus emerges as the most "perfect fluid" so far in Nature.

  7. 33 CFR 154.824 - Inerting, enriching, and diluting systems.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... this section; (2) When hydrocarbon analyzers are used, the lower hydrocarbon concentration reading... (i) or (k)(1) of this section; and (3) When hydrocarbon analyzers are used, the higher hydrocarbon... section. (f) Each oxygen or hydrocarbon analyzer required by this section must: (1) Be installed...

  8. 33 CFR 154.824 - Inerting, enriching, and diluting systems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... this section; (2) When hydrocarbon analyzers are used, the lower hydrocarbon concentration reading... (i) or (k)(1) of this section; and (3) When hydrocarbon analyzers are used, the higher hydrocarbon... section. (f) Each oxygen or hydrocarbon analyzer required by this section must: (1) Be installed...

  9. 33 CFR 154.824 - Inerting, enriching, and diluting systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...k)(2) of this section; (2) When hydrocarbon analyzers are used, the lower hydrocarbon concentration reading controls the enriching...1) of this section; and (3) When hydrocarbon analyzers are used, the higher...

  10. 33 CFR 154.2107 - Inerting, enriching, and diluting systems.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... requirements of 33 CFR 154.2100(e) when the oxygen concentration in the vapor collection line exceeds 60... the remotely operated cargo vapor shutoff valve required by 33 CFR 154.2101(a) when the oxygen... operated cargo vapor shutoff valve required by 33 CFR 154.2101(a) when the oxygen concentration in...

  11. Molecular simulation study of the surface barrier effect. Dilute gas limit

    SciTech Connect

    Ford, D.M.; Glandt, E.D.

    1995-07-20

    The mass transfer resistance associated with penetrating the mouth of a very small pore is evaluated using classical molecular dynamics simulation techniques. The effects of temperature, pore size, and thermal motion of the adsorbent atoms are studied for a slit pore mouth model. Adsorption followed by surface diffusion to the pore mouth makes a significant contribution to the mass transfer when the temperature is low or, equivalently, when the adsorptive potential is strong. Thermal vibrations of the adsorbent atoms have little effect on the adsorption/surface diffusion mechanisms but cause fluctuations in the effective pore mouth area which can significantly affect transport rates. Perhaps the most important observation is that when the pore size approaches the kinetic diameter of the gas molecules, changes of a few percent in the pore size cause order-of-magnitude changes in the resistance. Therefore, it is possible that the surface barrier effect observed in zeolites and carbon molecular sieves is governed by highly localized (single atomic layer) structural details. 19 refs., 7 figs., 1 tab.

  12. Inerting of magnesium dust cloud with Ar, N2 and CO2.

    PubMed

    Li, G; Yuan, C M; Fu, Y; Zhong, Y P; Chen, B Z

    2009-10-15

    Experiments were conducted on the inerting of magnesium dust with N(2), CO(2), and Ar. Comparing the maximum explosion pressure, maximum rate of pressure rise, and limiting oxygen concentration with different inertants, it was determined that Ar is not the best inert gas under all conditions as commonly believed. N(2) was more effective than Ar as an inertant. CO(2) provided more inerting effect than either Ar and N(2) in low magnesium dust concentrations, although explosibility was increased at higher dust concentrations. Both N(2) and CO(2) as inerting agents showed higher LOC values than Ar. These results indicated that N(2) is a more economical inerting gas than Ar for the tested coarse magnesium dust. PMID:19487075

  13. Dilution Confusion: Conventions for Defining a Dilution

    ERIC Educational Resources Information Center

    Fishel, Laurence A.

    2010-01-01

    Two conventions for preparing dilutions are used in clinical laboratories. The first convention defines an "a:b" dilution as "a" volumes of solution A plus "b" volumes of solution B. The second convention defines an "a:b" dilution as "a" volumes of solution A diluted into a final volume of "b". Use of the incorrect dilution convention could affect…

  14. Examination of charge dilution with EGR to reduce NO{sub x} emissions from a natural gas-fuelled 16 valve DOHC four-cylinder engine

    SciTech Connect

    Jaeaeskelaeinen, H.E.; Wallace, J.S.

    1994-10-01

    Charge dilution is commonly used to reduce emissions of nitrogen oxides (NO{sub x}) from internal combustion engine exhaust gas. The question of whether to use air or exhaust gas recirculation (EGR) as a charge diluent for the natural gas-fuelled test engine is addressed first. The decision to use EGR is based on the potentially lower NO{sub x} and unburned hydrocarbon emissions that could be achieved if a three-way catalyst were applied to the engine. The effect of EGR on the spark advance for maximum brake torque (MBT), NO{sub x}, and unburned hydrocarbon emissions is then examined in detail. The effect on fuel efficiency is discussed briefly. 37 refs., 16 figs., 3 tabs.

  15. Quantitative gas chromatography-olfactometry carried out at different dilutions of an extract. Key differences in the odor profiles of four high-quality Spanish aged red wines.

    PubMed

    Ferreira, V; Aznar, M; López, R; Cacho, J

    2001-10-01

    Four Spanish aged red wines made in different wine-making areas have been extracted, and the extracts and their 1:5, 1:50, and 1:500 dilutions have been analyzed by a gas chromatography-olfactometry (GC-O) approach in which three judges evaluated odor intensity on a four-point scale. Sixty-nine different odor regions were detected in the GC-O profiles of wines, 63 of which could be identified. GC-O data have been processed to calculate averaged flavor dilution factors (FD). Different ANOVA strategies have been further applied on FD and on intensity data to check for significant differences among wines and to assess the effects of dilution and the judge. Data show that FD and the average intensity of the odorants are strongly correlated (r(2) = 0.892). However, the measurement of intensity represents a quantitative advantage in terms of detecting differences. For some odorants, dilution exerts a critical role in the detection of differences. Significant differences among wines have been found in 30 of the 69 odorants detected in the experiment. Most of these differences are introduced by grape compounds such as methyl benzoate and terpenols, by compounds released by the wood, such as furfural, (Z)-whiskey lactone, Furaneol, 4-propylguaiacol, eugenol, 4-ethylphenol, 2,6-dimethoxyphenol, isoeugenol, and ethyl vanillate, by compounds formed by lactic acid bacteria, such as 2,3-butanedione and acetoine, or by compounds formed during the oxidative storage of wines, such as methional, sotolon, o-aminoacetophenone, and phenylacetic acid. The most important differences from a quantitative point of view are due to 2-methyl-3-mercaptofuran, 4-propylguaiacol, 2,6-dimethoxyphenol, and isoeugenol. PMID:11600028

  16. Pressurized pyrolysis of rice husk in an inert gas sweeping fixed-bed reactor with a focus on bio-oil deoxygenation.

    PubMed

    Qian, Yangyang; Zhang, Jie; Wang, Jie

    2014-12-01

    The pyrolysis of rice husk was conducted in a fixed-bed reactor with a sweeping nitrogen gas to investigate the effects of pressure on the pyrolytic behaviors. The release rates of main gases during the pyrolysis, the distributions of four products (char, bio-oil, water and gas), the elemental compositions of char, bio-oil and gas, and the typical compounds in bio-oil were determined. It was found that the elevation of pressure from 0.1MPa to 5.0MPa facilitated the dehydration and decarboxylation of bio-oil, and the bio-oils obtained under the elevated pressures had significantly less oxygen and higher calorific value than those obtained under atmospheric pressure. The former bio-oils embraced more acetic acid, phenols and guaiacols. The elevation of pressure increased the formation of CH4 partially via the gas-phase reactions. An attempt is made in this study to clarify "the pure pressure effect" and "the combined effect with residence time". PMID:25463787

  17. Dilution-based emissions sampling from stationary sources: Part 2--Gas-fired combustors compared with other fuel-fired systems.

    PubMed

    England, Glenn C; Watson, John G; Chow, Judith C; Zielinska, Barbara; Chang, M C Oliver; Loos, Karl R; Hidy, George M

    2007-01-01

    With the recent focus on fine particle matter (PM2.5), new, self-consistent data are needed to characterize emissions from combustion sources. Such data are necessary for health assessment and air quality modeling. To address this need, emissions data for gas-fired combustors are presented here, using dilution sampling as the reference. The dilution method allows for collection of emitted particles under conditions simulating cooling and dilution during entry from the stack into the air. The sampling and analysis of the collected particles in the presence of precursor gases, SO2 nitrogen oxide, volatile organic compound, and NH3 is discussed; the results include data from eight gas fired units, including a dual-fuel institutional boiler and a diesel engine powered electricity generator. These data are compared with results in the literature for heavy-duty diesel vehicles and stationary sources using coal or wood as fuels. The results show that the gas-fired combustors have very low PM2.5 mass emission rates in the range of approximately 10(-4) lb/million Btu (MMBTU) compared with the diesel backup generator with particle filter, with approximately 5 x 10(-3) lb/MMBTU. Even higher mass emission rates are found in coal-fired systems, with rates of approximately 0.07 lb/MMBTU for a bag-filter-controlled pilot unit burning eastern bituminous coal. The characterization of PM2.5 chemical composition from the gas-fired units indicates that much of the measured primary particle mass in PM2.5 samples is organic or elemental carbon and, to a much less extent, sulfate. Metal emissions are quite low compared with the diesel engines and the coal- or wood-fueled combustors. The metals found in the gas-fired combustor particles are low in concentration, similar in concentration to ambient particles. The interpretation of the particulate carbon emissions is complicated by the fact that an approximately equal amount of particulate carbon (mainly organic carbon) is found on the particle collector and a backup filter. It is likely that measurement artifacts, mostly adsorption of volatile organic compounds on quartz filters, are positively biasing "true" particulate carbon emission results. PMID:17269233

  18. Cross-correlation focus method with an electrostatic sensor array for local particle velocity measurement in dilute gas-solid two-phase flow

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Zhang, Jingyu; Gao, Wenbin; Ding, Hongbing; Wu, Weiping

    2015-11-01

    The gas-solid two-phase flow has been widely applied in the power, chemical and metallurgical industries. It is of great significance in the research of gas-solid two-phase flow to measure particle velocity at different locations in the pipeline. Thus, an electrostatic sensor array comprising eight arc-shaped electrodes was designed. The relationship between the cross-correlation (CC) velocity and the distribution of particle velocity, charge density and electrode spatial sensitivity was analysed. Then the CC sensitivity and its calculation method were proposed. According to the distribution of CC sensitivity, it was found that, between different electrode pairs, it had different focus areas. The CC focus method was proposed for particle velocity measurement at different locations and validated by a belt-style electrostatic induction experiment facility. Finally, the particle velocities at different locations with different flow conditions were measured to research the particle velocity distribution in a dilute horizontal pneumatic conveying pipeline.

  19. 7 CFR 201.19 - Inert matter.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Inert matter. 201.19 Section 201.19 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.19 Inert matter. The label shall show the percentage by weight of inert matter....

  20. 7 CFR 201.19 - Inert matter.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Inert matter. 201.19 Section 201.19 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.19 Inert matter. The label shall show the percentage by weight of inert matter....

  1. Inert wastes -- A live issue

    SciTech Connect

    Molus, P.; Rieley, D.; Sherlock, G.; Walmsley, K.

    1996-12-31

    This paper demonstrates why one county council in the UK has adopted a very proactive position towards inert waste and its reuse and recycling, and how that council is attempting to increase the use of this material. It describes how Babtie has worked with Berkshire County Council and gives an outline of Berkshire and the County`s responsibilities. The environmental/planning issues affecting minerals and waste in Berkshire and the approach the Council is adopting via policy documents and its role as a corporate body are discussed. The actions of the County Council are described with regard to increasing the reuse and recycling of inert wastes on the road network and the roles of specifications and contractors. The impact of some of the more relevant issues (markets, practical issues, planning, and supply and demand) is assessed.

  2. Asymmetric Inert Scalar Dark Matter

    E-print Network

    Dhen, Mikael

    2015-01-01

    In the quite minimal inert scalar doublet dark matter framework, we analyze what would be the effect of a $B-L$ asymmetry that could have been produced in the Universe thermal bath at high temperature. We show that, unless the "$\\lambda_5$" scalar interaction is tiny, this asymmetry is automatically reprocessed in part into a DM asymmetry that can easily dominate the DM relic density today. This scenario requires the inert DM mass scale to lie in the few-TeV range. Two types of relic density suppressions render this scenario viable: thermalization, from the same "$\\lambda_5$" interaction, of the asymmetries at temperature below the dark matter particle threshold, and DM particle-antiparticle oscillations.

  3. Bose-Einstein condensation in a dilute gas: the first 70 years and some recent experiments (Nobel Lecture).

    PubMed

    Cornell, Eric A; Wieman, Carl E

    2002-06-17

    Bose-Einstein condensates of dilute gases offer a rich field to study fundamental quantum-mechanical processes, manipulation of the speed at which light propogates, observation of atomic pair-formation and superfluidity, or even simulating white dwarf stars. Still more radical applications are on the horizon. However, their initial creation was a masterpiece of experimental physics. After an initial process of laser cooling (which itself won its developers the 1997 Nobel Prize), atoms in a magnetic-optical trap must be safely transferred into a purely magnetic trap, where the condensation process begins at 170 nK and 20 nK a pure condensate of 2000 atoms could be created. More astonishingly, Wieman and Cornell showed these low temperatures could be achieved in "bench scale" equipment rather than the massive pieces normally demanded by cryoscience. For their 1995 discovery of this new state of matter, they were awarded the 2001 Nobel Prize in Physics. PMID:12465486

  4. Modification of a commercial gas chromatography isotope ratio mass spectrometer for on-line carbon isotope dilution: Evaluation of its analytical characteristics for the quantification of organic compounds.

    PubMed

    Alonso Sobrado, Laura; Robledo Fernández, Mario; Cueto Díaz, Sergio; Ruiz Encinar, Jorge; García Alonso, J Ignacio

    2015-11-01

    We describe the instrumental modification of a commercial gas chromatography isotope ratio mass spectrometer (GC-IRMS) and its application for on-line carbon isotope dilution. The main modification consisted in the addition of a constant flow of enriched (13)CO2 diluted in helium after the chromatographic column through the splitter holder located inside the chromatographic oven of the instrument. In addition, and in contrast to the conventional mode of operation of GC-IRMS instruments where the signal at m/z 45 is amplified 100-fold with respect to the signal at m/z 44, the same signal amplification was used in both Faraday cups at m/z 44 and 45. Under these conditions isotope ratio precision for the ratio 44/45 was around 0.05% RSD (n=50). The evaluation of the instrument was performed with mixtures of organic compounds including 11 n-alkanes, 16 PAHs, 12 PCBs and 3 benzothiophenes. It was observed that compounds of very different boiling points could be analysed without discrimination in the injector when a Programmable Temperature Vaporizer (PTV) injector was employed. Moreover, the presence of heteroatoms (Cl or S) in the structure of the organic compounds did not affect their combustion efficiency and therefore the trueness of the results. Quantitative results obtained for all the analytes assayed were excellent in terms of precision (<3% RSD) and accuracy (average relative error?4%) and what is more important using a single and simple generic internal standard for quantification. PMID:26435309

  5. Gas-surface interactions using accommodation coefficients for a dilute and a dense gas in a micro- or nanochannel: heat flux predictions using combined molecular dynamics and Monte Carlo techniques.

    PubMed

    Nedea, S V; van Steenhoven, A A; Markvoort, A J; Spijker, P; Giordano, D

    2014-05-01

    The influence of gas-surface interactions of a dilute gas confined between two parallel walls on the heat flux predictions is investigated using a combined Monte Carlo (MC) and molecular dynamics (MD) approach. The accommodation coefficients are computed from the temperature of incident and reflected molecules in molecular dynamics and used as effective coefficients in Maxwell-like boundary conditions in Monte Carlo simulations. Hydrophobic and hydrophilic wall interactions are studied, and the effect of the gas-surface interaction potential on the heat flux and other characteristic parameters like density and temperature is shown. The heat flux dependence on the accommodation coefficient is shown for different fluid-wall mass ratios. We find that the accommodation coefficient is increasing considerably when the mass ratio is decreased. An effective map of the heat flux depending on the accommodation coefficient is given and we show that MC heat flux predictions using Maxwell boundary conditions based on the accommodation coefficient give good results when compared to pure molecular dynamics heat predictions. The accommodation coefficients computed for a dilute gas for different gas-wall interaction parameters and mass ratios are transferred to compute the heat flux predictions for a dense gas. Comparison of the heat fluxes derived using explicit MD, MC with Maxwell-like boundary conditions based on the accommodation coefficients, and pure Maxwell boundary conditions are discussed. A map of the heat flux dependence on the accommodation coefficients for a dense gas, and the effective accommodation coefficients for different gas-wall interactions are given. In the end, this approach is applied to study the gas-surface interactions of argon and xenon molecules on a platinum surface. The derived accommodation coefficients are compared with values of experimental results. PMID:25353885

  6. An experimental and numerical investigation on the influence of external gas recirculation on the HCCI autoignition process in an engine: Thermal, diluting, and chemical effects

    SciTech Connect

    Machrafi, Hatim; Cavadias, Simeon; Guibert, Philippe

    2008-11-15

    In order to contribute to the solution of controlling the autoignition in a homogeneous charge compression ignition (HCCI) engine, parameters linked to external gas recirculation (EGR) seem to be of particular interest. Experiments performed with EGR present some difficulties in interpreting results using only the diluting and thermal aspect of EGR. Lately, the chemical aspect of EGR is taken more into consideration, because this aspect causes a complex interaction with the dilution and thermal aspects of EGR. This paper studies the influence of EGR on the autoignition process and particularly the chemical aspect of EGR. The diluents present in EGR are simulated by N{sub 2} and CO{sub 2}, with dilution factors going from 0 to 46 vol%. For the chemically active species that could be present in EGR, the species CO, NO, and CH{sub 2}O are used. The initial concentration in the inlet mixture of CO and NO is varied between 0 and 170 ppm, while that of CH{sub 2}O alters between 0 and 1400 ppm. For the investigation of the effect of the chemical species on the autoignition, a fixed dilution factor of 23 vol% and a fixed EGR temperature of 70 C are maintained. The inlet temperature is held at 70 C, the equivalence ratios between 0.29 and 0.41, and the compression ratio at 10.2. The fuels used for the autoignition are n-heptane and PRF40. It appeared that CO, in the investigated domain, did not influence the ignition delays, while NO had two different effects. At concentrations up until 45 ppm, NO advanced the ignition delays for the PRF40 and at higher concentrations, the ignition delayed. The influence of NO on the autoignition of n-heptane seemed to be insignificant, probably due to the higher burn rate of n-heptane. CH{sub 2}O seemed to delay the ignition. The results suggested that especially the formation of OH radicals or their consumption by the chemical additives determines how the reactivity of the autoignition changed. (author)

  7. Headspace stir bar sorptive extraction-gas chromatography/mass spectrometry characterization of the diluted vapor phase of cigarette smoke delivered to an in vitro cell exposure chamber.

    PubMed

    Kaur, Navneet; Cabral, Jean-Louis; Morin, André; Waldron, Karen C

    2011-01-14

    Advanced smoke generation systems, such as the Borgwaldt RM20S(®) smoking machine used in combination with the BAT exposure chamber, allow for the generation, dilution and delivery of fresh cigarette smoke to cell or tissue cultures for in vitro cell culture analyses. Recently, our group confirmed that the Borgwaldt RM20S(®) is a reliable tool to generate and deliver repeatable and reproducible exposure concentrations of whole smoke to in vitro cultures. However, the relationship between dose and diluted smoke components found within the exposure chamber has not been characterized. The current study focused on the development of a headspace stir bar sorptive extraction (HSSE) method to chemically characterize some of the vapor phase components of cigarette smoke generated by the Borgwaldt RM20S(®) and collected within a cell culture exposure chamber. The method was based on passive sampling within the chamber by HSSE using a Twister™ stir bar. Following exposure, sorbed analytes were recovered using a thermal desorption unit and a cooled injection system coupled to gas chromatograph/mass spectrometry for identification and quantification. Using the HSSE method, sixteen compounds were identified. The desorption parameters were assessed using ten reference compounds and the following conditions led to the maximal response: desorption temperature of 200°C for 2 min with cryofocussing temperature of -75°C. During transfer of the stir bars to the thermal desorption system, significant losses of analytes were observed as a function of time; therefore, the exposure-to-desorption time interval was kept at the minimum of 10±0.5 min. Repeatability of the HSSE method was assessed by monitoring five reference compounds present in the vapor phase (10.1-12.9% RSD) and n-butyl acetate, the internal standard (18.5% RSD). The smoke dilution precision was found to be 17.2, 6.2 and 11.7% RSD for exposure concentrations of 1, 2 and 5% (v/v) cigarette vapor phase in air, respectively. A linear response of analyte abundance was observed as a function of dilution. Extrapolation to 100% (v/v) cigarette vapor phase, i.e., undiluted smoke, gave yields for the five compounds ranging from 6 to 450 ng for 10 min exposure. PMID:21163485

  8. Inert doublet model and LEP II limits

    SciTech Connect

    Lundstroem, Erik; Gustafsson, Michael; Edsjoe, Joakim

    2009-02-01

    The inert doublet model is a minimal extension of the standard model introducing an additional SU(2) doublet with new scalar particles that could be produced at accelerators. While there exists no LEP II analysis dedicated for these inert scalars, the absence of a signal within searches for supersymmetric neutralinos can be used to constrain the inert doublet model. This translation however requires some care because of the different properties of the inert scalars and the neutralinos. We investigate what restrictions an existing DELPHI Collaboration study of neutralino pair production can put on the inert scalars and discuss the result in connection with dark matter. We find that although an important part of the inert doublet model parameter space can be excluded by the LEP II data, the lightest inert particle still constitutes a valid dark matter candidate.

  9. Infrared reflectivity spectra of gas-source molecular beam epitaxy grown dilute InN{sub x}As{sub 1-x}/InP (001)

    SciTech Connect

    Talwar, Devki N.; Yang, Tzuen-Rong; Hsiung Lin, Hao; Chuan Feng, Zhe

    2013-02-04

    Vibrational spectra of gas-source molecular beam epitaxy grown dilute InN{sub x}As{sub 1-x}/InP (001) alloys are obtained using a Fourier-transform infrared (IR) spectroscopy. A triply degenerate N{sub As} local vibrational mode of T{sub d}-symmetry is observed near 438 cm{sup -1} corresponding to the In-N bond energy. The analysis of composition dependent infrared reflectivity spectra in InNAs has predicted a two-phonon-mode behavior. In In(Ga)-rich GaInNAs alloys the observed splitting of the N{sub As} local mode into a doublet for the N{sub As}-Ga{sub 1}(In{sub 1})In{sub 3}(Ga{sub 3}) pair-defect of C{sub 3v}-symmetry is consistent with our simulated results based on a sophisticated Green's function theory.

  10. Free electron in compressed inert gases

    SciTech Connect

    Gordon, E. B. Smirnov, B. M.

    2008-08-15

    The behavior of excess and intrinsic free electrons inside compressed inert gases is described as a function of pressure by using a pairwise approximation for the electron interaction with atomic surroundings. The change of sign from negative to positive for the xenon atom electric potential inside condensed xenon is predicted to occur at a pressure around 3 GPa, preventing slow electron embedding into solid xenon from the gas phase at higher pressure. To overcome this difficulty, the electrons should be injected into a solid sample just before its pulsed shock loading. The ionization of xenon by pressure and its further metallization are described by decreasing the forbidden gap at the expense of increasing the xenon ground electronic term and simultaneous splitting of the upper ionized electronic state. A good coincidence between the calculated and measured pressure of the dielectric-metal transition in xenon is demonstrated.

  11. Atmospheric carbon tetrafluoride: a nearly inert gas.

    PubMed

    Cicerone, R J

    1979-10-01

    An analysis of existing thermodynamic, photochemical, and kinetic data indicates that the dominant sinks for atmospheric carbon tetrafluoride (CF(4)) are in and above the mesosphere. Theoretical calculations predict an atmospheric residence time for CF(4) of over 10,000 years, about 100 times that for dichlorodifluoromethane (CF(2)Cl(2)) and monofluorotrichloromethane (CFC1(3)). It is predicted that CF(4) will be well mixed through the stratosphere and mesosphere; only one or two parts of hydrogen fluoride in 10(12) are predicted in the high stratosphere as a result of the decomposition of CF(4). Although natural sources of CF(4) cannot be ruled out, there are several likely industrial sources that may account for its present concentration. The principal environmental effect of CF(4) could be the trapping of outgoing planetary infrared energy in its intense bands near 8 micrometers. PMID:17812452

  12. Dilution-based emissions sampling from stationary sources: part 2 - gas-fired combustors compared with other fuel-fired systems

    SciTech Connect

    England, G.C.; Watson, J.G.; Chow, J.C.; Zielinska, B.; Chang, M.C.O.; Loos, K.R.; Hidy. G.M.

    2007-01-15

    With the recent focus on fine particle matter (PM2.5), new, self- consistent data are needed to characterize emissions from combustion sources. Emissions data for gas-fired combustors are presented, using dilution sampling as the reference. The sampling and analysis of the collected particles in the presence of precursor gases, SO{sub 2}, nitrogen oxide, volatile organic compound, and NH{sub 3} is discussed; the results include data from eight gas fired units, including a dual- fuel institutional boiler and a diesel engine powered electricity generator. These data are compared with results in the literature for heavy-duty diesel vehicles and stationary sources using coal or wood as fuels. The results show that the gas-fired combustors have very low PM2.5 mass emission rates in the range of {approximately}10{sup -4} lb/million Btu (MMBTU) compared with the diesel backup generator with particle filter, with {approximately} 5 x 10{sup -3} lb/MMBTU. Even higher mass emission rates are found in coal-fired systems, with rates of {approximately} 0.07 lb/MMBTU for a bag-filter-controlled pilot unit burning eastern bituminous coal. The characterization of PM2.5 chemical composition from the gas-fired units indicates that much of the measured primary particle mass in PM2.5 samples is organic or elemental carbon and, to a much less extent, sulfate. Metal emissions are low compared with the diesel engines and the coal- or wood-fueled combustors. The metals found in the gas- fired combustor particles are low in concentration. The interpretation of the particulate carbon emissions is complicated by the fact that an approximately equal amount of particulate carbon is found on the particle collector and a backup filter. It is likely that measurement artifacts are positively biasing 'true' particulate carbon emissions results. 49 refs., 1 fig., 12 tabs.

  13. Determination of ultratrace levels of tributyltin in waters by isotope dilution and gas chromatography coupled to tandem mass spectrometry.

    PubMed

    Rodríguez-Cea, Andrés; Rodríguez-González, Pablo; Font Cardona, Nuria; Aranda Mares, José Luís; Ballester Nebot, Salomé; García Alonso, J Ignacio

    2015-12-18

    The current EU legislation lays down the Environmental Quality Standards (EQS) of 45 priority substances in surface water bodies. In particular, the concentration of tributyltin (TBT) must not exceed 0.2ngL(-1) and analytical methodologies with a Limit of Quantification (LOQ) equal or below 0.06ngL(-1) are urged to be developed. This work presents a procedure for the determination of ultratrace levels of TBT in water samples by Isotope Dilution and GC-MS/MS operating in Selected Reaction Monitoring (SRM) mode which meets current EU requirements. The method requires the monitorization of five consecutive transitions (287>175 to 291>179) for the sensitive and selective detection of TBT. The measured isotopic distribution of TBT fragment ions was in agreement with the theoretical values computed by a polynomial expansion algorithm. The combined use of Tandem Mass Spectrometry, a sample volume of 250mL, the preconcentration of 1mL of organic phase to 30?L and an injection volume of 25?L by Programmed Temperature Vaporization provided a LOQ of 0.0426ngL(-1) for TBT (calculated as ten times the standard deviation of nine independent blanks). The recovery for TBT calculated in Milli-Q water at the EQS level was 106.3±4%. A similar procedure was also developed for the quantification of dibutyltin (DBT) and monobutyltin (MBT) in water samples showing satisfactory results. The method was finally implemented in a routine testing laboratory to demonstrate its applicability to real samples obtaining quantitative recoveries for TBT at the EQS level in mineral water, river water and seawater. PMID:26614170

  14. Validation of an isotope dilution gas chromatography-mass spectrometry method for combined analysis of oxysterols and oxyphytosterols in serum samples.

    PubMed

    Schött, Hans-Frieder; Lütjohann, Dieter

    2015-07-01

    We describe the validation of a method for the analysis of oxysterols, i.e. oxycholesterols and oxyphytosterols, in human serum using gas chromatography-mass spectrometry selected ion monitoring (GC-MS-SIM). Concentrations of 7?- and 7?-hydroxy-, and 7oxo-cholesterol, -campesterol, and -sitosterol as well as 4?-hydroxycholesterol and side-chain oxygenated 24S-, 25-, and 27-hydroxycholesterol were determined by isotope dilution methodology. After saponification at room temperature the oxysterols were extracted, separated from their substrates, cholesterol, campesterol, and sitosterol, by solid phase extraction, and subsequently derivatised to their corresponding trimethylsilyl-ethers prior to GC-MS-SIM. In order to prevent artificial autoxidation butylated hydroxytoluene and ethylenediaminetetraacetic acid were added. The validation of the method was performed according to the International Conference on Harmonisation guidance, including limits of detection and quantification, ranges, recovery and precision. Due to improved instrumental settings and work-up procedure, limits of detection and quantification ranged between 8.0-202.0pg/mL and 28.0-674pg/mL, respectively. Recovery data in five calibration points varied between 91.9% and 116.8% and in serum samples between 93.1% and 118.1%. The mean coefficient of variation (CV) for the recovery of all compounds was <10%. Well satisfying CVs for within-day precision (2.1-10.8%) and for between-day precision (2.3-12.1%) were obtained. More than 20 samples could be processed in a single routine day and test series of about 300 samples can be realised without impairment of the validation parameters during a sequence. Comparison of oxysterol and oxyphytosterol content in serum and plasma revealed no difference. A fully validated isotope dilution methodology for the quantification of oxycholesterols and oxyphytosterols from human serum or plasma is presented. PMID:25701095

  15. Characterization of the major odor-active compounds in Thai durian ( Durio zibethinus L. 'Monthong') by aroma extract dilution analysis and headspace gas chromatography-olfactometry.

    PubMed

    Li, Jia-Xiao; Schieberle, Peter; Steinhaus, Martin

    2012-11-14

    An aroma extract dilution analysis applied on the volatile fraction isolated from Thai durian by solvent extraction and solvent-assisted flavor evaporation resulted in 44 odor-active compounds in the flavor dilution (FD) factor range of 1-16384, 41 of which could be identified and 24 that had not been reported in durian before. High FD factors were found for ethyl (2S)-2-methylbutanoate (fruity; FD 16384), ethyl cinnamate (honey; FD 4096), and 1-(ethylsulfanyl)ethanethiol (roasted onion; FD 1024), followed by 1-(ethyldisulfanyl)-1-(ethylsulfanyl)ethane (sulfury, onion), 2(5)-ethyl-4-hydroxy-5(2)-methylfuran-3(2H)-one (caramel), 3-hydroxy-4,5-dimethylfuran-2(5H)-one (soup seasoning), ethyl 2-methylpropanoate (fruity), ethyl butanoate (fruity), 3-methylbut-2-ene-1-thiol (skunky), ethane-1,1-dithiol (sulfury, durian), 1-(methylsulfanyl)ethanethiol (roasted onion), 1-(ethylsulfanyl)propane-1-thiol (roasted onion), and 4-hydroxy-2,5-dimethylfuran-3(2H)-one (caramel). Among the highly volatile compounds screened by static headspace gas chromatography-olfactometry, hydrogen sulfide (rotten egg), acetaldehyde (fresh, fruity), methanethiol (rotten, cabbage), ethanethiol (rotten, onion), and propane-1-thiol (rotten, durian) were found as additional potent odor-active compounds. Fourteen of the 41 characterized durian odorants showed an alkane-1,1-dithiol, 1-(alkylsulfanyl)alkane-1-thiol, or 1,1-bis(alkylsulfanyl)alkane structure derived from acetaldehyde, propanal, hydrogen sulfide, and alkane-1-thiols. Among these, 1-(propylsulfanyl)ethanethiol, 1-{[1-(methylsulfanyl)ethyl]sulfanyl}ethanethiol, and 1-{[1-(ethylsulfanyl)ethyl]sulfanyl}ethanethiol were reported for the first time in a natural product. PMID:23088286

  16. Identification of odorants in frankincense (Boswellia sacra Flueck.) by aroma extract dilution analysis and two-dimensional gas chromatography-mass spectrometry/olfactometry.

    PubMed

    Niebler, Johannes; Buettner, Andrea

    2015-01-01

    Frankincense has been known, traded and used throughout the ages for its exceptional aroma properties, and is still commonly used in both secular and religious settings to convey a pleasant odor. Surprisingly, the odoriferous principle(s) underlying its unique odor profile have never been published. In this study, resin samples of Boswellia sacra Flueck. from both Somalia and Oman were investigated by aroma extract dilution analysis. In a comprehensive, odor-activity guided approach both chemo-analytical and human-sensory parameters were used to identify odor active constituents of the volatile fraction of B. sacra. Among the key odorants found were ?-pinene, ?-myrcene, linalool, p-cresol and two unidentified sesquiterpenoids. Overall, a total of 23 odorants were detected and analyzed by gas chromatography-olfactometry and heart-cut two-dimensional gas chromatography-mass spectrometry/olfactometry. The majority of the identified odorant compounds were oxygenated monoterpenes, along with some relevant mono- and sesquiterpenes and only one diterpenoid substance. Several of these compounds were reported here for the first time as odorous constituents in B. sacra. Identifying bioactive compounds might support a better understanding with regard to the potential benefits of frankincense, for example in aromatherapy or ecclesial settings. PMID:25468535

  17. Thermodynamics of Dilute Solutions.

    ERIC Educational Resources Information Center

    Jancso, Gabor; Fenby, David V.

    1983-01-01

    Discusses principles and definitions related to the thermodynamics of dilute solutions. Topics considered include dilute solution, Gibbs-Duhem equation, reference systems (pure gases and gaseous mixtures, liquid mixtures, dilute solutions), real dilute solutions (focusing on solute and solvent), terminology, standard states, and reference systems.…

  18. Airborne measurements of sulfur dioxide, dimethyl sulfide, carbon disulfide, and carbonyl sulfide by isotope dilution gas chromatography/mass spectrometry

    NASA Technical Reports Server (NTRS)

    Bandy, Alan R.; Thornton, Donald C.; Driedger, Arthur R., III

    1993-01-01

    A gas chromatograph/mass spectrometer is described for determining atmospheric sulfur dioxide, carbon disulfide, dimethyl sulfide, and carbonyl sulfide from aircraft and ship platforms. Isotopically labelled variants of each analyte were used as internal standards to achieve high precision. The lower limit of detection for each species for an integration time of 3 min was 1 pptv for sulfur dioxide and dimethyl sulfide and 0.2 pptv for carbon disulfide and carbonyl sulfide. All four species were simultaneously determined with a sample frequency of one sample per 6 min or greater. When only one or two species were determined, a frequency of one sample per 4 min was achieved. Because a calibration is included in each sample, no separate calibration sequence was needed. Instrument warmup was only a few minutes. The instrument was very robust in field deployments, requiring little maintenance.

  19. Quantification of polycyclic aromatic hydrocarbons based on comprehensive two-dimensional gas chromatography-isotope dilution mass spectrometry.

    PubMed

    Amador-Muñoz, Omar; Villalobos-Pietrini, Rafael; Aragón-Piña, Antonio; Tran, Tin C; Morrison, P; Marriott, Philip J

    2008-08-01

    Comprehensive two-dimensional gas chromatography (GCxGC) offers favourable resolution and sensitivity compared with conventional one-dimensional gas chromatography (1D-GC), as reported in many studies. These characteristics are of major interest when analytes are in trace concentration, and are present in complex mixtures, as is the case of polycyclic aromatic hydrocarbons (PAHs) in atmospheric particulate samples. Whilst GCxGC has been widely applied to identification of different types of analytes in several matrices, less seldom has it been used for quantification of these analytes. Although several quantitative methods have been proposed, they may be tedious and/or require considerable user development. Whereas quantification in 1D-GC is a routine and well-established procedure, in GCxGC, it is not so straightforward, especially where novel or untested procedures have yet to be incorporated into software packages. In the present study, it is proposed that a subset of the modulated peaks generated for each solute may be summed, based on the specific target ion mass of each compound present in a certified standard reference material (SRM) 1649a (urban dust). The ratio between a PAH and its corresponding deuterated (PAH-d) form showed that there is no statistical loss of sensitivity when this ratio is calculated based on whether the total sum of modulated peaks, or if only the two or the three most intense modulated peaks, are employed. Manual integration may be required, and here was found to give more acceptable values than automatic integration. Automated integration has been shown here to underestimate the modulated peak responses when low concentrations of PAHs were analyzed. Although for most PAHs good agreement with the certified values were observed, the analytical method needs to be further optimized for some of the other PAH, as can be see with those PAH with high variability in the range of urban dust analyzed. PMID:18620359

  20. Flammability limits of dusts: Minimum inerting concentrations

    SciTech Connect

    Dastidar, A.G.; Amyotte, P.R.; Going, J.; Chatrathi, K.

    1999-05-01

    A new flammability limit parameter has been defined as the Minimum Inerting Concentration (MIC). This is the concentration of inertant required to prevent a dust explosion regardless of fuel concentration. Previous experimental work at Fike in a 1-m{sup 3} spherical chamber has shown this flammability limit to exist for pulverized coal dust and cornstarch. In the current work, inerting experiments with aluminum, anthraquinone and polyethylene dusts as fuels were performed, using monoammonium phosphate and sodium bicarbonate as inertants. The results show that an MIC exists only for anthraquinone inerted with sodium bicarbonate. The other combustible dust and inertant mixtures did not show a definitive MIC, although they did show a strong dependence between inerting level and suspended fuel concentration. As the fuel concentration increased, the amount of inertant required to prevent an explosion decreased. Even though a definitive MIC was not found for most of the dusts an effective MIC can be estimated from the data. The use of MIC data can aid in the design of explosion suppression schemes.

  1. Finite Dilution Inverse Gas Chromatography as a Versatile Tool To Determine the Surface Properties of Biofillers for Plastic Composite Applications.

    PubMed

    Yao, Zhitong; Ge, Liuqin; Yang, Wenye; Xia, Meisheng; Ji, Xiaosheng; Jin, Meiqing; Tang, Junhong; Dienstmaier, Jürgen

    2015-07-01

    An improved understanding of a filler’s surface properties is important for determining the most effective polymer reinforcement fillers. In this work, the surface characteristics of two biofillers, namely, clam shell modified by hydrochloric acid (AMF) and furfural (FMF), were investigated using inverse gas chromatography (IGC). The IGC results showed that the dispersive surface energy (?(S)(D)) contributed the major part to the total surface energy for the biofillers. The values changed as a function of surface coverages, meaning that both samples were energetically fairly heterogeneous. The ?(S)(D) calculated with the Dorris–Gray method was larger than that calculated with the Schultz method, with a ?(S,Dorris–Gray)(D)/?(S,Schultz)(D) ratio of 1.10. Compared to AMF, FMF possessed higher ?(S)(D) value; however, this difference was compensated by specific (acid–base) surface energy (?(S)(AB)). Both samples predominantly interacted with ethanol and acetonitrile, implying an amphoteric nature of the material surfaces. Gutmann acid and base number profiles indicated that the surfaces of both samples were more basic in nature. The FMF showed a lower total work of cohesion (W(Coh)(total)) value compared to the AMF, which could lead to an increase in composite performance. PMID:26017338

  2. Analysis of nitromethane from samples exposed in vitro to chloropicrin by stable isotope dilution headspace gas chromatography with mass spectrometry.

    PubMed

    Halme, Mia; Pesonen, Maija; Grandell, Toni; Kuula, Matti; Pasanen, Markku; Vähäkangas, Kirsi; Vanninen, Paula

    2015-10-01

    Chloropicrin (trichloronitromethane) is a widely used soil fumigant and an old chemical warfare agent. The metabolism of chloropicrin is not well known in mammals but nitromethane has been shown to be one of its main metabolites. Here, a fast and simple headspace gas chromatography with mass spectrometry method was applied for the measurement of nitromethane from aqueous samples. The analytical method was validated using stable isotope labeled internal standard and a small sample volume of 260 ?L. No conventional sample preparation steps were needed. The method was accurate (relative standard deviations ?1.5%) and linear (R(2) = 0.9996) within the concentration range of 0.1-6.0 ?g/mL. This method was used to measure nitromethane in in vitro incubations with human and pig liver cell fractions containing enzymes for xenobiotic metabolism, exposed to chloropicrin. The results indicate that the presence of glutathione is necessary for the formation of nitromethane from chloropicrin. Also, nitromethane was formed mostly in liver cytosol fractions, but not in microsomal fractions after the incubation with chloropicrin. Our results suggest that although nitromethane is not the unequivocal biomarker of chloropicrin exposure, this method could be applied for screening the elevated levels in humans after chloropicrin exposure. PMID:26255649

  3. A dynamic inert metal anode.

    SciTech Connect

    Hryn, J. N.

    1998-11-09

    A new concept for a stable anode for aluminum electrowinning is described. The anode consists of a cup-shaped metal alloy container filled with a molten salt that contains dissolved aluminum. The metal alloy can be any of a number of alloys, but it must contain aluminum as a secondary alloying metal. A possible alloy composition is copper with 5 to 15 weight percent aluminum. In the presence of oxygen, aluminum on the metal anode's exterior surface forms a continuous alumina film that is thick enough to protect the anode from chemical attack by cryolite during electrolysis and thin enough to maintain electrical conductivity. However, the alumina film is soluble in cryolite, so it must be regenerated in situ. Film regeneration is achieved by the transport of aluminum metal from the anode's molten salt interior through the metal wall to the anode's exterior surface, where the transported aluminum oxidizes to alumina in the presence of evolving oxygen to maintain the protective alumina film. Periodic addition of aluminum metal to the anode's interior keeps the aluminum activity in the molten salt at the desired level. This concept for an inert anode is viable as long as the amount of aluminum produced at the cathode greatly exceeds the amount of aluminum required to maintain the anode's protective film.

  4. Dilutions Made Easy.

    ERIC Educational Resources Information Center

    Kamin, Lawrence

    1996-01-01

    Presents problems appropriate for high school and college students that highlight dilution methods. Promotes an understanding of dilution methods in order to prevent the unnecessary waste of chemicals and glassware in biology laboratories. (JRH)

  5. Bino Dark Matter and Big Bang Nucleosynthesis in the Constrained E6SSM with Massless Inert Singlinos

    E-print Network

    Jonathan P. Hall; Stephen F. King

    2011-05-11

    We discuss a new variant of the E6 inspired supersymmetric standard model (E6SSM) in which the two inert singlinos are exactly massless and the dark matter candidate has a dominant bino component. A successful relic density is achieved via a novel mechanism in which the bino scatters inelastically into heavier inert Higgsinos during the time of thermal freeze-out. The two massless inert singlinos contribute to the effective number of neutrino species at the time of Big Bang Nucleosynthesis, where the precise contribution depends on the mass of the Z' which keeps them in equilibrium. For example for mZ' > 1300 GeV we find Neff \\approx 3.2, where the smallness of the additional contribution is due to entropy dilution. We study a few benchmark points in the constrained E6SSM with massless inert singlinos to illustrate this new scenario.

  6. Serial Dilution Simulation Lab

    ERIC Educational Resources Information Center

    Keler, Cynthia; Balutis, Tabitha; Bergen, Kim; Laudenslager, Bryanna; Rubino, Deanna

    2010-01-01

    Serial dilution is often a difficult concept for students to understand. In this short dry lab exercise, students perform serial dilutions using seed beads. This exercise helps students gain skill at performing dilutions without using reagents, bacterial cultures, or viral cultures, while being able to visualize the process.

  7. Application of the carbon dioxide-barium hydroxide hydrate gas-solid reaction for the treatment of dilute carbon dioxide-bearing gas streams

    SciTech Connect

    Haag, G.L.

    1983-09-01

    The removal of trace components from gas streams via irreversible gas-solid reactions in an area of interest to the chemical engineering profession. This research effort addresses the use of fixed beds of Ba(OH)/sub 2/ hydrate flakes for the removal of an acid gas, CO/sub 2/, from air that contains approx. 330 ppM/sub v/ CO/sub 2/. Areas of investigation encompassed: (1) an extensive literature review of Ba(OH)/sub 2/ hydrate chemistry, (2) microscale studies on 0.150-g samples to develop a better understanding of the reaction, (3) process studies at the macroscale level with 10.2-cm-ID fixed-bed reactors, and (4) the development of a model for predicting fixed-bed performance. Experimental studies indicated fixed beds of commercial Ba(OH)/sub 2/.8H/sub 2/O flakes at ambient temperatures to be capable of high CO/sub 2/-removal efficiencies (effluent concentrations <100 ppB), high reactant utilization (>99%), and an acceptable pressure drop (1.8 kPa/m at a superficial gas velocity of 13 cm/s). Ba(OH)/sub 2/.8H/sub 2/O was determined to be more reactive toward CO/sub 2/ than either Ba(OH)/sub 2/.3H/sub 2/O or Ba(OH)/sub 2/.1H/sub 2/O. A key variable in the development of this fixed-bed process was relative humidity. Operation at conditions with effluent relative humidities >60% resulted in significant recrystallization and restructuring of the flake and subsequent pressure-drop problems.

  8. 7 CFR 201.19 - Inert matter.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.19 Inert matter. The label shall show the percentage by...

  9. 7 CFR 201.19 - Inert matter.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.19 Inert matter. The label shall show the percentage by...

  10. 7 CFR 201.19 - Inert matter.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.19 Inert matter. The label shall show the percentage by...

  11. Axial grading of inert matrix fuels

    SciTech Connect

    Recktenwald, G. D.; Deinert, M. R.

    2012-07-01

    Burning actinides in an inert matrix fuel to 750 MWd/kg IHM results in a significant reduction in transuranic isotopes. However, achieving this level of burnup in a standard light water reactor would require residence times that are twice that of uranium dioxide fuels. The reactivity of an inert matrix assembly at the end of life is less than 1/3 of its beginning of life reactivity leading to undesirable radial and axial power peaking in the reactor core. Here we show that axial grading of the inert matrix fuel rods can reduce peaking significantly. Monte Carlo simulations are used to model the assembly level power distributions in both ungraded and graded fuel rods. The results show that an axial grading of uranium dioxide and inert matrix fuels with erbium can reduces power peaking by more than 50% in the axial direction. The reduction in power peaking enables the core to operate at significantly higher power. (authors)

  12. Isentropic Compression of Multicomponent Mixtures of Fuels and Inert Gases

    NASA Technical Reports Server (NTRS)

    Barragan, Michelle; Julien, Howard L.; Woods, Stephen S.; Wilson, D. Bruce; Saulsberry, Regor L.

    2000-01-01

    In selected aerospace applications of the fuels hydrazine and monomethythydrazine, there occur conditions which can result in the isentropic compression of a multicomponent mixture of fuel and inert gas. One such example is when a driver gas such as helium comes out of solution and mixes with the fuel vapor, which is being compressed. A second example is when product gas from an energetic device mixes with the fuel vapor which is being compressed. Thermodynamic analysis has shown that under isentropic compression, the fuels hydrazine and monomethylhydrazine must be treated as real fluids using appropriate equations of state. The appropriate equations of state are the Peng-Robinson equation of state for hydrazine and the Redlich-Kwong-Soave equation of state for monomethylhydrazine. The addition of an inert gas of variable quantity and input temperature and pressure to the fuel compounds the problem for safety design or analysis. This work provides the appropriate thermodynamic analysis of isentropic compression of the two examples cited. In addition to an entropy balance describing the change of state, an enthalpy balance is required. The presence of multicomponents in the system requires that appropriate mixing rules are identified and applied to the analysis. This analysis is not currently available.

  13. Dark Matter from the Inert Doublet Model

    E-print Network

    Laura Lopez Honorez

    2007-06-01

    The Inert Doublet Model is an extension of the Standard Model including one extra ``Inert scalar doublet'' and an exact $Z_2$ symmetry. The ``Inert scalar'' provides a new candidate for dark matter. We present a systematic analysis of the dark matter abundance assuming the standard freeze-out mechanism and investigate the potentialities for direct and gamma indirect detection. We show that the dark matter candidate saturates the WMAP dark matter density in two rather separate mass ranges, one between 40 and 80 GeV, the other one over 400 GeV. We also show that the model should be within the range of future experiments, like GLAST and EDELWEISS II or ZEPLIN.

  14. Inert strength of pristine silica glass fibers

    SciTech Connect

    Smith, W.L.; Michalske, T.A.

    1993-11-01

    Silica glass fibers have been produced and tested under ultra high vacuum (UHV) conditions to investigate the inert strength of pristine fibers in absence of reactive agents. Analysis of the coefficient of variation in diameter ({upsilon}{sub d}) vs the coefficient of variation of breaking strength ({upsilon}{sub {sigma}}) does not adequately explain the variation of breaking stress. Distribution of fiber tensile strength data suggests that the inert strength of such fibers is not single valued and that the intrinsic strength is controlled by defects in the glass. Furthermore, comparison of room temperature UHV data with LN{sub 2} data indicates that these intrinsic strengths are not temperature dependent.

  15. Two systems developed for purifying inert atmospheres

    NASA Technical Reports Server (NTRS)

    Foster, M. S.; Johnson, C. E.; Kyle, M. L.

    1969-01-01

    Two systems, one for helium and one for argon, are used for purifying inert atmospheres. The helium system uses an activated charcoal bed at liquid nitrogen temperature to remove oxygen and nitrogen. The argon system uses heated titanium sponge to remove nitrogen and copper wool beds to remove oxygen. Both use molecular sieves to remove water vapor.

  16. 7 CFR 201.51 - Inert matter.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the embryo missing. (2) Grass florets and caryopses classed as inert: (i) Glumes and empty florets of... axis missing (the scutellum excluded); (iii) Immature free caryopses devoid of embryo and/or endosperm... Brassica with the seed coats entirely removed. (4) Immature seed units, devoid of both embryo and...

  17. 7 CFR 201.51 - Inert matter.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... the embryo missing. (2) Grass florets and caryopses classed as inert: (i) Glumes and empty florets of... axis missing (the scutellum excluded); (iii) Immature free caryopses devoid of embryo and/or endosperm... Brassica with the seed coats entirely removed. (4) Immature seed units, devoid of both embryo and...

  18. 46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Vinyl chloride: Inhibiting and inerting. 154...Requirements § 154.1740 Vinyl chloride: Inhibiting and inerting. When a vessel is carrying vinyl chloride, the master shall ensure that:...

  19. 46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Vinyl chloride: Inhibiting and inerting. 154...Requirements § 154.1740 Vinyl chloride: Inhibiting and inerting. When a vessel is carrying vinyl chloride, the master shall ensure that:...

  20. 46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Vinyl chloride: Inhibiting and inerting. 154...Requirements § 154.1740 Vinyl chloride: Inhibiting and inerting. When a vessel is carrying vinyl chloride, the master shall ensure that:...

  1. 46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Vinyl chloride: Inhibiting and inerting. 154...Requirements § 154.1740 Vinyl chloride: Inhibiting and inerting. When a vessel is carrying vinyl chloride, the master shall ensure that:...

  2. 46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Vinyl chloride: Inhibiting and inerting. 154...Requirements § 154.1740 Vinyl chloride: Inhibiting and inerting. When a vessel is carrying vinyl chloride, the master shall ensure that:...

  3. 46 CFR 154.912 - Inerted spaces: Relief devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Inerted spaces: Relief devices. 154.912 Section 154.912 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY... Atmospheric Control in Cargo Containment Systems § 154.912 Inerted spaces: Relief devices. Inerted spaces...

  4. 46 CFR 154.912 - Inerted spaces: Relief devices.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Inerted spaces: Relief devices. 154.912 Section 154.912 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY... Atmospheric Control in Cargo Containment Systems § 154.912 Inerted spaces: Relief devices. Inerted spaces...

  5. 46 CFR 154.912 - Inerted spaces: Relief devices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Inerted spaces: Relief devices. 154.912 Section 154.912 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY... Atmospheric Control in Cargo Containment Systems § 154.912 Inerted spaces: Relief devices. Inerted spaces...

  6. 46 CFR 154.912 - Inerted spaces: Relief devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Inerted spaces: Relief devices. 154.912 Section 154.912 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY... Atmospheric Control in Cargo Containment Systems § 154.912 Inerted spaces: Relief devices. Inerted spaces...

  7. 46 CFR 154.912 - Inerted spaces: Relief devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Inerted spaces: Relief devices. 154.912 Section 154.912 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY... Atmospheric Control in Cargo Containment Systems § 154.912 Inerted spaces: Relief devices. Inerted spaces...

  8. Inert gases in fines at three levels of the trench at Van Serg Crater

    NASA Technical Reports Server (NTRS)

    Jordan, J. L.; Heymann, D.

    1975-01-01

    Inert-gas measurements were conducted with three soil samples collected from a trench of about 17 cm depth which had been dug at Station 9, approximately 60-m southeast of the rim of Van Serg Crater on the moon. The particular trench is interesting because it is located in the continuous ejecta blanket of a relatively young crater. The results of the inert-gas measurements are presented in a table. They confirm an earlier conclusion reported by Heymann et al. (1974) that fines from Station 9 are among the most gas rich in the whole landing site. The three fines are agglutinate rich and most of the trapped gas is contained in the constructional particles. Agglutinate contents of fines tend to decrease rapidly for particles greater than about 250 micrometers.

  9. 40 CFR 90.421 - Dilute gaseous exhaust sampling and analytical system description.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... false Dilute gaseous exhaust sampling and analytical system description...90.421 Dilute gaseous exhaust sampling and analytical system description. (a) General. The exhaust gas sampling system described in this...

  10. 40 CFR 89.419 - Dilute gaseous exhaust sampling and analytical system description.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... false Dilute gaseous exhaust sampling and analytical system description...89.419 Dilute gaseous exhaust sampling and analytical system description. (a) General. The exhaust gas sampling system described in this...

  11. 40 CFR 89.419 - Dilute gaseous exhaust sampling and analytical system description.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... false Dilute gaseous exhaust sampling and analytical system description...89.419 Dilute gaseous exhaust sampling and analytical system description. (a) General. The exhaust gas sampling system described in this...

  12. 40 CFR 90.421 - Dilute gaseous exhaust sampling and analytical system description.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... false Dilute gaseous exhaust sampling and analytical system description...90.421 Dilute gaseous exhaust sampling and analytical system description. (a) General. The exhaust gas sampling system described in this...

  13. 40 CFR 89.419 - Dilute gaseous exhaust sampling and analytical system description.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... false Dilute gaseous exhaust sampling and analytical system description...89.419 Dilute gaseous exhaust sampling and analytical system description. (a) General. The exhaust gas sampling system described in this...

  14. 40 CFR 91.421 - Dilute gaseous exhaust sampling and analytical system description.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Dilute gaseous exhaust sampling and analytical system description...91.421 Dilute gaseous exhaust sampling and analytical system description. (a) General. The exhaust gas sampling system described in this...

  15. 40 CFR 90.421 - Dilute gaseous exhaust sampling and analytical system description.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2013-07-01 true Dilute gaseous exhaust sampling and analytical system description...90.421 Dilute gaseous exhaust sampling and analytical system description. (a) General. The exhaust gas sampling system described in this...

  16. 40 CFR 91.421 - Dilute gaseous exhaust sampling and analytical system description.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Dilute gaseous exhaust sampling and analytical system description...91.421 Dilute gaseous exhaust sampling and analytical system description. (a) General. The exhaust gas sampling system described in this...

  17. 40 CFR 89.419 - Dilute gaseous exhaust sampling and analytical system description.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2013-07-01 true Dilute gaseous exhaust sampling and analytical system description...89.419 Dilute gaseous exhaust sampling and analytical system description. (a) General. The exhaust gas sampling system described in this...

  18. 40 CFR 91.421 - Dilute gaseous exhaust sampling and analytical system description.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Dilute gaseous exhaust sampling and analytical system description...91.421 Dilute gaseous exhaust sampling and analytical system description. (a) General. The exhaust gas sampling system described in this...

  19. 40 CFR 90.421 - Dilute gaseous exhaust sampling and analytical system description.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... false Dilute gaseous exhaust sampling and analytical system description...90.421 Dilute gaseous exhaust sampling and analytical system description. (a) General. The exhaust gas sampling system described in this...

  20. 40 CFR 91.421 - Dilute gaseous exhaust sampling and analytical system description.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2013-07-01 true Dilute gaseous exhaust sampling and analytical system description...91.421 Dilute gaseous exhaust sampling and analytical system description. (a) General. The exhaust gas sampling system described in this...

  1. Bose-Einstein condensation of magnons in Cs{sub 2}CuCl{sub 4}: A dilute gas limit near the saturation magnetic field

    SciTech Connect

    Kovrizhin, D. L.; Yushankhai, V.; Siurakshina, L.

    2006-10-01

    Based on the realistic spin Hamiltonian for the frustrated quasi-two-dimensional spin-1/2 antiferromagnet Cs{sub 2}CuCl{sub 4}, a three-dimensional spin ordering in the applied magnetic field B near the saturation value B{sub c} is studied within the magnon Bose-Einstein condensation scenario. Using a hard-core boson formulation of the spin model, a strongly anisotropic magnon dispersion in Cs{sub 2}CuCl{sub 4} is calculated. In the dilute magnon limit near B{sub c}, the hard-core boson constraint results in an effective magnon interaction which is treated in the Hartree-Fock approximation. The critical temperature T{sub c} is calculated as a function of the magnetic field B and compared with the phase boundary T{sub c}(B) experimentally determined in Cs{sub 2}CuCl{sub 4} [Phys. Rev. Lett. 95, 127202 (2005)].

  2. Muco-inert nanoparticle probes and drug carriers

    NASA Astrophysics Data System (ADS)

    Wang, Ying-Ying

    2011-12-01

    Mucus coats the exposed surfaces of the eyes and respiratory, gastrointestinal (GI) and cervicovaginal (CV) tracts, and protects mucosal tissues against pathogens and other foreign particulates. Most foreign particles are effectively trapped in mucus through steric and adhesive interactions, and are rapidly eliminated by different mucus clearance mechanisms. Nevertheless, mucus also immobilizes conventional drug and gene carriers, thereby precluding sustained and targeted drug delivery to mucosal sites. Synthetic particles engineered with muco-inert surfaces, and some viruses, can readily penetrate mucus gel, and may serve as useful probes to understand the biophysical barrier properties of mucus. Improved understanding of the mucus barrier could provide insights into methods to enhance drug and gene delivery at mucosal surfaces, as well as understanding the occasional failure of mucus to protect against infection or injury. Recently, muco-inert nanoparticles were developed by conjugating a dense layer of low MW polyethylene glycol to particle surfaces. Since they are slowed only by steric obstruction from the mucus mesh, various sized muco-inert nanoparticles can be used to probe the microstructure and microrheology of mucus. I applied this technique to determine whether the mucus barrier may be altered by exogenous factors, including the presence of detergent, pH changes and synthetic nanoparticles. I first studied the microrheology of native human cervicovaginal mucus (CVM), and found that CVM behaves as a viscoelastic solid at length scales ? 1 microm (preventing large particles from diffusing through) but as a viscoelastic liquid at length scales up to at least 500 nm (allowing smaller particles to diffuse through low viscosity fluid-filled pores). Treating CVM with a nonionic detergent, N9, shifted the viscoelastic liquid-solid transition point to < 200 nm, suggesting hydrophobic interactions between mucin fibers play an important role in regulating the mucus microstructure and consequently the microrheology. Indeed, N9 caused the average mucus pore size to decrease from ˜340 nm to 130 nm. I then looked at the effect of pH on mucus and found that the microstructure of CVM is essentially pH-independent over a broad range of physiological pH. Between pH 4 (the native pH of CVM) and 6--7, the average pore size in the mucus mesh remained unchanged, and between pH 1--2 and 8--9, there was at most a 2-fold drop in the average pore size (likely due to changes in electrostatic vs. hydrophobic interactions between mucin fibers). Finally, I found that mucoadhesive synthetic nanoparticles, at sufficiently high concentrations, can bundle mucin fibers and create large openings in the mucus microstructure. Disruption of the mucus barrier in this manner allowed a greater fraction of large (1 microm) muco-inert particles to diffuse through the mucus mesh. Muco-inert nanoparticles---also referred to as "mucus-penetrating particles" (MPP)---offer the potential for sustained and targeted drug delivery to mucosal surfaces. By penetrating luminal mucus layers, MPP may be able to reach the slowly cleared adherent mucus layer or deep folds of the epithelium and thereby achieve prolonged retention. I first measured the long range penetration of MPP compared to conventional mucoadhesive particles (CP) into CVM. With minimal dilution of CVM, MPP could penetrate up to 200 microm over 1 hr with ˜530 particles/mm2 penetrating 100 microm or more, while CP remained immobilized (note that physiological mucus layer thicknesses are no more than ˜200 microm). Furthermore, with 30% v/v dilution, MPP could penetrate up to 1.5 mm over 1 hr with ˜74,000 particles/mm2 penetrating 100 microm or more, while CP continued to remain stuck. I then studied the distribution and retention of MPP vs. CP in the mouse vagina to determine whether improved mucus penetration leads to more uniform distribution and prolonged retention. I found that MPP were not only more uniformly distributed in the vaginal lumen, but also penetrated deep into epithel

  3. Helium dilution refrigeration system

    DOEpatents

    Roach, P.R.; Gray, K.E.

    1988-09-13

    A helium dilution refrigeration system operable over a limited time period, and recyclable for a next period of operation is disclosed. The refrigeration system is compact with a self-contained pumping system and heaters for operation of the system. A mixing chamber contains [sup 3]He and [sup 4]He liquids which are precooled by a coupled container containing [sup 3]He liquid, enabling the phase separation of a [sup 3]He rich liquid phase from a dilute [sup 3]He-[sup 4]He liquid phase which leads to the final stage of a dilution cooling process for obtaining low temperatures. The mixing chamber and a still are coupled by a fluid line and are maintained at substantially the same level with the still cross sectional area being smaller than that of the mixing chamber. This configuration provides maximum cooling power and efficiency by the cooling period ending when the [sup 3]He liquid is depleted from the mixing chamber with the mixing chamber nearly empty of liquid helium, thus avoiding unnecessary and inefficient cooling of a large amount of the dilute [sup 3]He-[sup 4]He liquid phase. 2 figs.

  4. Helium dilution refrigeration system

    DOEpatents

    Roach, Patrick R. (Darien, IL); Gray, Kenneth E. (Naperville, IL)

    1988-01-01

    A helium dilution refrigeration system operable over a limited time period, and recyclable for a next period of operation. The refrigeration system is compact with a self-contained pumping system and heaters for operation of the system. A mixing chamber contains .sup.3 He and .sup.4 He liquids which are precooled by a coupled container containing .sup.3 He liquid, enabling the phase separation of a .sup.3 He rich liquid phase from a dilute .sup.3 He-.sup.4 He liquid phase which leads to the final stage of a dilution cooling process for obtaining low temperatures. The mixing chamber and a still are coupled by a fluid line and are maintained at substantially the same level with the still cross sectional area being smaller than that of the mixing chamber. This configuration provides maximum cooling power and efficiency by the cooling period ending when the .sup.3 He liquid is depleted from the mixing chamber with the mixing chamber nearly empty of liquid helium, thus avoiding unnecessary and inefficient cooling of a large amount of the dilute .sup.3 He-.sup.4 He liquid phase.

  5. C(240)-----The most Chemically Inert Fullerene?

    NASA Technical Reports Server (NTRS)

    Haddon, R. C.; Scuseria, G. E.; Smalley, R. E.

    1997-01-01

    The reactivity of the fullerenes is primarily a function of their strain, as measured by the pyramidalization angle or curvature of the conjugated carbon atoms. The development of faceting in the structure of large icosahedral fullerenes leads to a minimum in the value of the maximum fullerene pyramidalization angle that lies in the vicinity of C-240. On this basis it is argued that C-240 will be the most chemically inert fullerene. This observation explains the production of [10,10] single-walled nanotubes because a C-240 hemisphere is required for the nucleation of such tubes.

  6. Method for retarding dye fading during archival storage of developed color photographic film. [inert atmosphere

    NASA Technical Reports Server (NTRS)

    Hoover, R. B.; Rhodes, C. M. (inventors)

    1981-01-01

    Dye fading during archival storage of developed color photographic film is retarded by placing the film in a sealed, opaque vault, introducing a dry, pressurized inert gas into the vault while the latter is vented, and sealing the vault after the air within the vault has been purged and replaced by the inert gas. Preferably, the gas is nitrogen; and the vault is stored at a temperature below room temperature to preserve the color photographic emulsions on the film contained within the vault. For short-term storage, sodium thiocyanate pads charged with water are placed within the vault. For long term storage, the interior of the vault is kept at a low relative humidity.

  7. 40 CFR 1066.140 - Diluted exhaust flow calibration.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...and Analytical Gas Specifications...calibrate flow meters for diluted...subsonic venturi or ultrasonic flow to measure...element, or an ultrasonic flow meter. Use a reference...Reserved] (j) Ultrasonic flow meter...

  8. Total synthesis of isotopically enriched Si-29 silica NPs as potential spikes for isotope dilution quantification of natural silica NPs.

    PubMed

    Pálmai, Marcell; Szalay, Roland; Bartczak, Dorota; Varga, Zoltán; Nagy, Lívia Naszályi; Gollwitzer, Christian; Krumrey, Michael; Goenaga-Infante, Heidi

    2015-05-01

    A new method was developed for the preparation of highly monodisperse isotopically enriched Si-29 silica nanoparticles ((29)Si-silica NPs) with the purpose of using them as spikes for isotope dilution mass spectrometry (IDMS) quantification of silica NPs with natural isotopic distribution. Si-29 tetraethyl orthosilicate ((29)Si-TEOS), the silica precursor was prepared in two steps starting from elementary silicon-29 pellets. In the first step Si-29 silicon tetrachloride ((29)SiCl4) was prepared by heating elementary silicon-29 in chlorine gas stream. By using a multistep cooling system and the dilution of the volatile and moisture-sensitive (29)SiCl4 in carbon tetrachloride as inert medium we managed to reduce product loss caused by evaporation. (29)Si-TEOS was obtained by treating (29)SiCl4 with absolute ethanol. Structural characterisation of (29)Si-TEOS was performed by using (1)H and (13)C nuclear magnetic resonance (NMR) spectroscopy and Fourier-transform infrared (FTIR) spectroscopy. For the NP preparation, a basic amino acid catalysis route was used and the resulting NPs were analysed using transmission electron microscopy (TEM), small angle X-ray scattering (SAXS), dynamic light scattering (DLS) and zeta potential measurements. Finally, the feasibility of using enriched NPs for on-line field-flow fractionation coupled with multi-angle light scattering and inductively coupled plasma mass spectrometry (FFF/MALS/ICP-MS) has been demonstrated. PMID:25617615

  9. I. I. Rabi Prize Lecture: Paradox Lost and Paradox Regained: Recent Experimental Results in Dilute-Gas Bose-Einstein Condensation

    NASA Astrophysics Data System (ADS)

    Cornell, Eric A.

    1997-04-01

    In the two years since Bose-Einstein condensation was first observed [1,2,3] in dilute vapors of the alkali metals, a wide variety of experimental studies has been performed on these exotic systems. Some of the recent results out of JILA (for instance a critical temperature measurement [4]) have been in excellent agreement with theeoretical expectations. Others (for instance the behavior of low-lying condensate excitations at finite-T [5]) have been more puzzling. I will discuss the recently observed two-component condensates [6] and provide also an overview of recent studies [7] of the coherence properties of condensates. ([1] M. H. Anderson, J. R. Ensher, M. R. Matthews, C. E. Wieman and E. A. Cornell, Science 269, 198 (1995). [2] K. B. Davis, M.-O. Mewes, M. R. Andrews, N. J. van Druten, D. S. Durfee, D. M. Kurn, W. Kettle, Phys. Rev. Lett. 75, 3696 (1995). [3] C. C. Bradley, C. A. Sackett, and R. G. Hulet, Phys. Rev. Lett. (in press). [4] J. R. Ensher, D. S. Jin, M. R. Matthews, C. E. Wieman and E. A. Cornell, Phys. Rev. Lett. 77, 4984 (1996). [5] D. S. Jin, M. R. Matthews, J. R. Ensher, C. E. Wieman and E. A. Cornell, Phys. Rev. Lett. (in press). [6] C. J. Myatt, E. A. Burt, R. W. Ghrist, E. A. Cornell and C. E. Wieman, Phys. Rev. Lett. (in press). [7] M. R. Andrews, C. G. Townsend, H.-J. Miesner, D. S. Durfee, D. M. Kurn and W. Ketterle, Science (in press).)

  10. Improving the efficiency of organic light emitting diodes by use of a diluted light-emitting layer

    E-print Network

    S. H. Mohan; K. Garre; N. Bhandari; M. Cahay

    2011-07-13

    The use of a thin mixed layer consisting of an inert diluent material and a light emitting material between the hole-transport layer and electron-transport layer of organic light-emitting diodes leads to an increase in the external quantum efficiency. The efficiency improvement is highly dependent on the thickness of the diluted light-emitting layer and driving current. Significant improvement seen at low current densities is explained in terms of effective hole confinement by the mixed layer while a modest decreases in efficiency at higher current densities may be attributed to luminescence quenching at the hole-transport layer/inert diluents material interface. The phenomena are demonstrated with three different inert diluents materials. A maximum external quantum efficiency improvement of about 40% is found for a diluted light-emitting layer thickness between 40 {\\AA} and 60 {\\AA}.

  11. Preliminary fabrication and characterisation of inert matrix and thoria fuels for plutonium disposition in light water reactors

    NASA Astrophysics Data System (ADS)

    Vettraino, F.; Magnani, G.; La Torretta, T.; Marmo, E.; Coelli, S.; Luzzi, L.; Ossi, P.; Zappa, G.

    1999-08-01

    The plutonium disposition is presently acknowledged as a most urgent issue at the world level. Inert matrix and thoria fuel concepts for Pu burning in LWRs show good potential in providing effective and ultimate solutions to this issue. In non-fertile (U-free) inert matrix fuel, plutonium oxide is diluted within inert oxides such as stabilised ZrO 2, Al 2O 3, MgO or MgAl 2O 4. Thoria addition, which helps improve neutronic characteristics of inert fuels, appears as a promising variant of U-free fuel. In the context of an R&D activity aimed at assessing the feasibility of the fuel concept above, simulated fuel pellets have been produced both from dry-powder metallurgy and the sol-gel route. Results show that they can be fabricated by matching basic nuclear grade specifications such as the required geometry, density and microstructure. Some characterisation testing dealing with thermo-physical properties, ion irradiation damage and solubility also have been started. Results from thermo-physical measurements at room temperature have been achieved. A main feature stemming from solubility testing outcomes is a very high chemical stability which should render the fuel strongly diversion resistant and suitable for direct final disposal in deep geological repository (once-through solution).

  12. Automatic diluter for bacteriological samples.

    PubMed Central

    Trinel, P A; Bleuze, P; Leroy, G; Moschetto, Y; Leclerc, H

    1983-01-01

    The described apparatus, carrying 190 tubes, allows automatic and aseptic dilution of liquid or suspended-solid samples. Serial 10-fold dilutions are programmable from 10(-1) to 10(-9) and are carried out in glass tubes with screw caps and split silicone septa. Dilution assays performed with strains of Escherichia coli and Bacillus stearothermophilus permitted efficient conditions for sterilization of the needle to be defined and showed that the automatic dilutions were as accurate and as reproducible as the most rigorous conventional dilutions. Images PMID:6338826

  13. Kinetics simulation for natural gas conversion to unsaturated C? hydrocarbons 

    E-print Network

    Yang, Li

    2003-01-01

    . In this process, methane is decomposed to ethylene, acetylene and carbon. Ethylene and acetylene are the desired products, while carbon formation should be stopped in the decomposition reaction. Some researchers have studied the dilution effect of various inert...

  14. Determination of 1-methyl-1H-1,2,4-triazole in soils contaminated by rocket fuel using solid-phase microextraction, isotope dilution and gas chromatography-mass spectrometry.

    PubMed

    Yegemova, Saltanat; Bakaikina, Nadezhda V; Kenessov, Bulat; Koziel, Jacek A; Nauryzbayev, Mikhail

    2015-10-01

    Environmental monitoring of Central Kazakhstan territories where heavy space booster rockets land requires fast, efficient, and inexpensive analytical methods. The goal of this study was to develop a method for quantitation of the most stable transformation product of rocket fuel, i.e., highly toxic unsymmetrical dimethylhydrazine - 1-methyl-1H-1,2,4-triazole (MTA) in soils using solid-phase microextraction (SPME) in combination with gas chromatography-mass spectrometry. Quantitation of organic compounds in soil samples by SPME is complicated by a matrix effect. Thus, an isotope dilution method was chosen using deuterated analyte (1-(trideuteromethyl)-1H-1,2,4-triazole; MTA-d3) for matrix effect control. The work included study of the matrix effect, optimization of a sample equilibration stage (time and temperature) after spiking MTA-d3 and validation of the developed method. Soils of different type and water content showed an order of magnitude difference in SPME effectiveness of the analyte. Isotope dilution minimized matrix effects. However, proper equilibration of MTA-d3 in soil was required. Complete MTA-d3 equilibration at temperatures below 40°C was not observed. Increase of temperature to 60°C and 80°C enhanced equilibration reaching theoretical MTA/MTA-d3 response ratios after 13 and 3h, respectively. Recoveries of MTA depended on concentrations of spiked MTA-d3 during method validation. Lowest spiked MTA-d3 concentration (0.24 mg kg(-1)) provided best MTA recoveries (91-121%). Addition of excess water to soil sample prior to SPME increased equilibration rate, but it also decreased method sensitivity. Method detection limit depended on soil type, water content, and was always below 1 mg kg(-1). The newly developed method is fully automated, and requires much lower time, labor and financial resources compared to known methods. PMID:26078153

  15. Effect of adduct formation with molecular nitrogen on the measured collisional cross sections of transition metal-1,10-phenanthroline complexes in traveling wave ion-mobility spectrometry: N2 is not always an "inert" buffer gas.

    PubMed

    Rijs, Nicole J; Weiske, Thomas; Schlangen, Maria; Schwarz, Helmut

    2015-10-01

    The number of separations and analyses of molecular species using traveling wave ion-mobility spectrometry-mass spectrometry (TWIMS-MS) is increasing, including those extending the technique to analytes containing metal atoms. A critical aspect of such applications of TWIMS-MS is the validity of the collisional cross sections (CCSs) measured and whether they can be accurately calibrated against other ion-mobility spectrometry (IMS) techniques. Many metal containing species have potential reactivity toward molecular nitrogen, which is present in high concentration in the typical Synapt-G2 TWIMS cell. Here, we analyze the effect of nitrogen on the drift time of a series of cationic 1,10-phenanthroline complexes of the late transition metals, [(phen)M](+), (M = Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, and Hg) in order to understand potential deviations from expected drift time behaviors. These metal complexes were chosen for their metal open-coordination site and lack of rotameric species. The target species were generated via electrospray ionization (ESI), analyzed using TWIMS in N2 drift gas, and the observed drift time trends compared. Theoretically derived CCSs for all species (via both the projection approximation and trajectory method) were also compared. The results show that, indeed, for metal containing species in this size regime, reaction with molecular nitrogen has a dramatic effect on measured drift times and must not be ignored when comparing and interpreting TWIMS arrival time distributions. Density-functional theory (DFT) calculations are employed to analyze the periodic differences due to the metal's interaction with nitrogen (and background water) in detail. PMID:26378338

  16. 46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Vinyl chloride: Inhibiting and inerting. 154.1740... Operating Requirements § 154.1740 Vinyl chloride: Inhibiting and inerting. When a vessel is carrying vinyl chloride, the master shall ensure that: (a) Section 154.1818 is met; or (b) Section 154.1710 is met,...

  17. 46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Vinyl chloride: Inhibiting and inerting. 154.1740... Operating Requirements § 154.1740 Vinyl chloride: Inhibiting and inerting. When a vessel is carrying vinyl chloride, the master shall ensure that: (a) Section 154.1818 is met; or (b) Section 154.1710 is met,...

  18. Electrolytic production of high purity aluminum using inert anodes

    DOEpatents

    Ray, Siba P. (Murrysville, PA); Liu, Xinghua (Monroeville, PA); Weirauch, Jr., Douglas A. (Murrysville, PA)

    2001-01-01

    A method of producing commercial purity aluminum in an electrolytic reduction cell comprising inert anodes is disclosed. The method produces aluminum having acceptable levels of Fe, Cu and Ni impurities. The inert anodes used in the process preferably comprise a cermet material comprising ceramic oxide phase portions and metal phase portions.

  19. Electrolytic production of high purity aluminum using ceramic inert anodes

    DOEpatents

    Ray, Siba P. (Murrysville, PA); Liu, Xinghua (Monroeville, PA); Weirauch, Douglas A. (Murrysville, PA); DiMilia, Robert A. (Baton Rouge, LA); Dynys, Joseph M. (New Kensington, PA); Phelps, Frankie E. (Apollo, PA); LaCamera, Alfred F. (Trafford, PA)

    2002-01-01

    A method of producing commercial purity aluminum in an electrolytic reduction cell comprising ceramic inert anodes is disclosed. The method produces aluminum having acceptable levels of Fe, Cu and Ni impurities. The ceramic inert anodes used in the process may comprise oxides containing Fe and Ni, as well as other oxides, metals and/or dopants.

  20. 46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Vinyl chloride: Inhibiting and inerting. 154.1740... Operating Requirements § 154.1740 Vinyl chloride: Inhibiting and inerting. When a vessel is carrying vinyl chloride, the master shall ensure that: (a) Section 154.1818 is met; or (b) Section 154.1710 is met,...

  1. 46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Vinyl chloride: Inhibiting and inerting. 154.1740... Operating Requirements § 154.1740 Vinyl chloride: Inhibiting and inerting. When a vessel is carrying vinyl chloride, the master shall ensure that: (a) Section 154.1818 is met; or (b) Section 154.1710 is met,...

  2. 46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Vinyl chloride: Inhibiting and inerting. 154.1740... Operating Requirements § 154.1740 Vinyl chloride: Inhibiting and inerting. When a vessel is carrying vinyl chloride, the master shall ensure that: (a) Section 154.1818 is met; or (b) Section 154.1710 is met,...

  3. Phosphorus diffusion in isoconcentration backgrounds under inert conditions in silicon

    E-print Network

    Florida, University of

    Phosphorus diffusion in isoconcentration backgrounds under inert conditions in silicon Jay P. John (Received 29 May 1992; accepted for publication 31 December 1992) The diffusivity of phosphorus in isoconcentration backgrounds under inert conditions in silicon is investigated. Phosphorus is implanted at low dose

  4. Diluted magnetic oxides

    NASA Astrophysics Data System (ADS)

    Li, XiaoLi; Qi, ShiFei; Jiang, FengXian; Quan, ZhiYong; Xu, XiaoHong

    2013-01-01

    In this review, we review the progress of research on ZnO- and In2O3-based diluted magnetic oxides (DMOs). Firstly, we present the preparation and characterization of DMOs. The former includes the preparation methods and conditions, and the latter includes the characterization techniques for measuring microstructures. Secondly, we introduce the magnetic and transport properties of DMOs, as well as the relationship between them. Thirdly, the origin and mechanism of the ferromagnetism are discussed. Fourthly, we introduce other related work, including computational work and pertinent heterogeneous structures, such as multilayers and magnetic tunnel junctions. Finally, we provide an overview and outlook for DMOs.

  5. Probing the center-vortex area law in d=3: The role of inert vortices

    SciTech Connect

    Cornwall, John M.

    2006-03-15

    In center-vortex theory, beyond the simplest picture of confinement several conceptual problems arise that are the subject of this paper. Recall that confinement arises through configuration averaging of phase factors associated with the gauge center group, raised to powers depending on the total Gauss link number of a vortex ensemble with a given Wilson loop. The simplest approach to confinement counts this link number by counting the number of vortices, considered in d=3 as infinitely long closed self-avoiding random walks of fixed step length, piercing any surface spanning the Wilson loop. Problems arise because a given vortex may pierce a given spanning surface several times without being linked or without contributing a nontrivial phase factor, or it may contribute a nontrivial phase factor appropriate to a smaller number of pierce points. We estimate the dilution factor {alpha}, due to these inert or partially inert vortices, that reduces the ratio of fundamental string tension K{sub F} to the areal density {rho} of vortices from the ratio given by elementary approaches and find {alpha}=0.6{+-}0.1. Then we show how inert vortices resolve the problem that the link number of a given vortex-Wilson-loop configuration is the same for any spanning surface of whatever area, yet a unique area (of a minimal surface) appears in the area law. Third, we discuss semiquantitatively a configuration of two distinct Wilson loops separated by a variable distance, and show how inert vortices govern the transition between two possible forms of the area law (one at small loop separation, the other at large), and point out the different behaviors in SU(2) and higher groups, notably SU(3). The result is a finite-range van der Waals force between the two loops. Finally, in a problem related to the double-loop problem, we argue that the analogs of inert vortices do not affect the fact that, in the SU(3) baryonic area law, the mesonic string tension appears.

  6. Dilute oriented loop models

    E-print Network

    Eric Vernier; Jesper Lykke Jacobsen; Hubert Saleur

    2015-09-25

    We study a model of dilute oriented loops on the square lattice, where each loop is compatible with a fixed, alternating orientation of the lattice edges. This implies that loop strands are not allowed to go straight at vertices, and results in an enhancement of the usual O(n) symmetry to U(n). The corresponding transfer matrix acts on a number of representations (standard modules) that grows exponentially with the system size. We derive their dimension and those of the centraliser by both combinatorial and algebraic techniques. A mapping onto a field theory permits us to identify the conformal field theory governing the critical range, $n \\le 1$. We establish the phase diagram and the critical exponents of low-energy excitations. For generic n, there is a critical line in the universality class of the dilute O(2n) model, terminating in an SU(n+1) point. The case n=1 maps onto the critical line of the six-vertex model, along which exponents vary continuously.

  7. Inert Higgs doublet extension of the NMSSM

    NASA Astrophysics Data System (ADS)

    Kyae, Bumseok

    2014-04-01

    We introduce one pair of inert Higgs doublets {Hd,Hu} and singlets {Nc,N}, and consider their couplings with the Higgs doublets of the minimal supersymmetric standard model (MSSM), W ?yNNchuHd+yN'NhdHu. We assign extra U(1)Z' gauge charges only to the extra vectorlike superfields, and so all the MSSM superfields remain neutral under the new U(1)Z'. They can be an extension of the "? term," W ??Shuhd in the next-to MSSM (NMSSM). Because of the U(1)Z', the maximally allowed low energy value of yN can be lifted up to 0.85, avoiding a Landau pole (LP) below the grand unification scale. Such colorless vectorlike superfields remarkably enhance the radiative MSSM Higgs mass particularly for large tan? through the yN term and the corresponding holomorphic soft term. As a result, the lower bound of ? and the upper bound of tan? can be relaxed to disappear from the restricted parameter space of the original NMSSM, 0.6?? ?0.7 and 1

  8. An analysis of the effect of inert gases on ozone generation using dielectric barrier discharge in oxygen

    NASA Astrophysics Data System (ADS)

    Wei, Linsheng; Yuan, Dingkun; Zhang, Yafang; Hu, Zhaoji; Tan, Zhihong; Dong, Guopan; Tao, Siqi

    2014-01-01

    This paper studies the influence of inert gases He, Ar, Kr and Xe on ozone generation in a dielectric barrier reactor fed by oxygen feed gas. Results show that inert gas additions would lead to lower applied voltage, discharge power and reduced field. The electron energy distribution function shifts to the right though inert gas addition would lead to a lower reduced field with He, Ar and Kr addition, but it shifts to the left with Xe addition. The effective electron density decreases with inert gas content. With respect to Ar/O2, Kr/O2 and Xe/O2 mixture, conversion ratio of oxygen into ozone and ozone yield would increase with increasing Ar, Kr or Xe content, the growth rates follow the order of Xe > Kr > Ar. Such behaviors can be ascribed to the fact that Ar*, Kr* and Xe* could provide another effective pathway to produce oxygen atom through penning dissociation of O2 and metastable species due to their relatively low excitation threshold and considerable rate coefficients.

  9. Evaluation of the metabolic chiral inversion of d-selenomethionine in rats by stable isotope dilution gas chromatography-mass spectrometry.

    PubMed

    Matsukawa, Takehisa; Hasegawa, Hiroshi; Goto, Hitomi; Shinohara, Yoshihiko; Shinohara, Atsuko; Omori, Yuki; Ichida, Kimiyoshi; Yokoyama, Kazuhito

    2015-12-10

    The stereoselective pharmacokinetics of selenomethionine enantiomers in rats has been studied to evaluate the chiral inversion of d-selenomethionine to the l-enantiomer. After bolus intravenous administration of d- or l-selenomethionine to rats, the plasma concentrations of these two enantiomers were determined by stereoselective gas chromatography-mass spectrometry with selected ion monitoring. This method involved derivatization of selenomethionine enantiomers with HCl in methanol to form methyl ester followed by N-acylation with (+)-?-methoxy-?-trifluoromethylphenylacetyl chloride to form the diastereomeric amide, and separation of the diastereomer on GC with an achiral column. Plasma concentrations of administered d- and l-selenomethionine declined with terminal half-lives of 96±17min and 91±6min, respectively. l-Selenomethionine appeared rapidly in plasma after administration of d-selenomethionine, whereas d-selenomethionine was not detected in plasma after administration of l-selenomethionine. The fraction of conversion of d-selenomethionine to l-selenomethionine was estimated to be 61.3±14.5%. The present method evaluates the stereoselective pharmacokinetics of selenomethionine enantiomers, including the estimation of the metabolic chiral inversion. PMID:26001566

  10. 40 CFR 174.705 - Inert ingredients from sexually compatible plant.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Inert ingredients from sexually compatible plant. 174.705 Section 174.705 Protection...PROGRAMS PROCEDURES AND REQUIREMENTS FOR PLANT-INCORPORATED PROTECTANTS List of Approved...Inert ingredients from sexually compatible plant. An inert ingredient, and...

  11. 40 CFR 174.705 - Inert ingredients from sexually compatible plant.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Inert ingredients from sexually compatible plant. 174.705 Section 174.705 Protection...PROGRAMS PROCEDURES AND REQUIREMENTS FOR PLANT-INCORPORATED PROTECTANTS List of Approved...Inert ingredients from sexually compatible plant. An inert ingredient, and...

  12. 40 CFR 174.705 - Inert ingredients from sexually compatible plant.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Inert ingredients from sexually compatible plant. 174.705 Section 174.705 Protection...PROGRAMS PROCEDURES AND REQUIREMENTS FOR PLANT-INCORPORATED PROTECTANTS List of Approved...Inert ingredients from sexually compatible plant. An inert ingredient, and...

  13. 40 CFR 174.705 - Inert ingredients from sexually compatible plant.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Inert ingredients from sexually compatible plant. 174.705 Section 174.705 Protection...PROGRAMS PROCEDURES AND REQUIREMENTS FOR PLANT-INCORPORATED PROTECTANTS List of Approved...Inert ingredients from sexually compatible plant. An inert ingredient, and...

  14. 40 CFR 174.705 - Inert ingredients from sexually compatible plant.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Inert ingredients from sexually compatible plant. 174.705 Section 174.705 Protection...PROGRAMS PROCEDURES AND REQUIREMENTS FOR PLANT-INCORPORATED PROTECTANTS List of Approved...Inert ingredients from sexually compatible plant. An inert ingredient, and...

  15. Inert gas test of two 12-cm magnetostatic thrusters

    NASA Technical Reports Server (NTRS)

    Ramsey, W. D.

    1982-01-01

    Comparative performance tests were conducted with 12 cm line and ring magnetic cusp thrusters. Shell anode and magnetoelectrostatic containment boundary anode configurations were evaluated with each magnet array. The best performance was achieved with the 12-cm ring cusp-shell anode configuration. Argon operation of this configuration produced 65-81 percent mass utilization efficiency at 170-208 watts/single-charged-equivalent (SCE) ampere beam. Xenon test results showed 75-95 percent utilization at 162-188 watts/SCE ampere beam.

  16. Inert Welding/Brazing Gas Filters and Dryers

    NASA Technical Reports Server (NTRS)

    Goudy, Jerry

    2009-01-01

    The use of hybridized carbon/silicon carbide (C/SiC) fabric to reinforce ceramic matrix composite face sheets and the integration of such face sheets with a foam core creates a sandwich structure capable of withstanding high-heat-flux environments (150 W/sq cm) in which the core provides a temperature drop of 1,000 C between the surface and the back face without cracking or delamination of the structure. The composite face sheet exhibits a bilinear response, which results from the SiC matrix not being cracked on fabrication. In addition, the structure exhibits damage tolerance under impact with projectiles, showing no penetration to the back face sheet. These attributes make the composite ideal for leading-edge structures and control surfaces in aerospace vehicles, as well as for acreage thermal protection systems and in high-temperature, lightweight stiffened structures. By tailoring the coefficient of thermal expansion (CTE) of a carbon fiber containing ceramic matrix composite (CMC) face sheet to match that of a ceramic foam core, the face sheet and the core can be integrally fabricated without any delamination. Carbon and SiC are woven together in the reinforcing fabric. Integral densification of the CMC and the foam core is accomplished with chemical vapor deposition, eliminating the need for bond-line adhesive. This means there is no need to separately fabricate the core and the face sheet, or to bond the two elements together, risking edge delamination during use. Fibers of two or more types are woven together on a loom. The carbon and ceramic fibers are pulled into the same "pick" location during the weaving process. Tow spacing may be varied to accommodate the increased volume of the combined fiber tows while maintaining a target fiber volume fraction in the composite. Foam pore size, strut thickness, and ratio of face sheet to core thickness can be used to tailor thermal and mechanical properties. The anticipated CTE for the hybridized composite is managed by the choice of constituents, varying fiber tow sizes and constituent part ratios. This structural concept provides high strength and stiffness at low density 1.06 g/cu cm in panels tested. Varieties of face sheet constructions are possible, including variations in fiber type and weave geometry. The integrated structures possible with this composite could eliminate the need for non-load-bearing thermal protection systems on top of a structural component. The back sheet can readily be integrated to substructures through the incorporation of ribs. This would eliminate weight and cost for aerospace missions.

  17. 33 CFR 157.164 - Use of inert gas system.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...tank is crude oil washed, the oxygen content in that tank is 8...a mixture of gases with an oxygen content of 8 percent or less by volume. (ii) A positive atmospheric pressure. (5) During...cargo control room when the oxygen content exceeds 8 percent...

  18. 33 CFR 157.164 - Use of inert gas system.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...tank is crude oil washed, the oxygen content in that tank is 8...a mixture of gases with an oxygen content of 8 percent or less by volume. (ii) A positive atmospheric pressure. (5) During...cargo control room when the oxygen content exceeds 8 percent...

  19. 33 CFR 157.164 - Use of inert gas system.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...tank is crude oil washed, the oxygen content in that tank is 8...a mixture of gases with an oxygen content of 8 percent or less by volume. (ii) A positive atmospheric pressure. (5) During...cargo control room when the oxygen content exceeds 8 percent...

  20. 33 CFR 157.164 - Use of inert gas system.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...tank is crude oil washed, the oxygen content in that tank is 8...a mixture of gases with an oxygen content of 8 percent or less by volume. (ii) A positive atmospheric pressure. (5) During...cargo control room when the oxygen content exceeds 8 percent...

  1. 33 CFR 157.164 - Use of inert gas system.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...tank is crude oil washed, the oxygen content in that tank is 8...a mixture of gases with an oxygen content of 8 percent or less by volume. (ii) A positive atmospheric pressure. (5) During...cargo control room when the oxygen content exceeds 8 percent...

  2. 33 CFR 157.164 - Use of inert gas system.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... oxygen content of 8 percent or less by volume. (ii) A positive atmospheric pressure. (5) During COW operations, a crew member monitors the instrumentation under 46 CFR 32.53-60(a)(1), except if...

  3. 33 CFR 157.164 - Use of inert gas system.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... oxygen content of 8 percent or less by volume. (ii) A positive atmospheric pressure. (5) During COW operations, a crew member monitors the instrumentation under 46 CFR 32.53-60(a)(1), except if...

  4. 33 CFR 157.164 - Use of inert gas system.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... oxygen content of 8 percent or less by volume. (ii) A positive atmospheric pressure. (5) During COW operations, a crew member monitors the instrumentation under 46 CFR 32.53-60(a)(1), except if...

  5. 33 CFR 157.164 - Use of inert gas system.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... oxygen content of 8 percent or less by volume. (ii) A positive atmospheric pressure. (5) During COW operations, a crew member monitors the instrumentation under 46 CFR 32.53-60(a)(1), except if...

  6. Continuous distributions of specific ventilation recovered from inert gas washout

    NASA Technical Reports Server (NTRS)

    Lewis, S. M.; Evans, J. W.; Jalowayski, A. A.

    1978-01-01

    A new technique is described for recovering continuous distributions of ventilation as a function of tidal ventilation/volume ratio from the nitrogen washout. The analysis yields a continuous distribution of ventilation as a function of tidal ventilation/volume ratio represented as fractional ventilations of 50 compartments plus dead space. The procedure was verified by recovering known distributions from data to which noise had been added. Using an apparatus to control the subject's tidal volume and FRC, mixed expired N2 data gave the following results: (a) the distributions of young, normal subjects were narrow and unimodal; (b) those of subjects over age 40 were broader with more poorly ventilated units; (c) patients with pulmonary disease of all descriptions showed enlarged dead space; (d) patients with cystic fibrosis showed multimodal distributions with the bulk of the ventilation going to overventilated units; and (e) patients with obstructive lung disease fell into several classes, three of which are illustrated.

  7. Preliminary Design Report Shippingport Spent Fuel Drying and Inerting System

    SciTech Connect

    JEPPSON, D.W.

    2000-05-18

    A process description and system flow sheets have been prepared to support the design/build package for the Shippingport Spent Fuel Canister drying and inerting process skid. A process flow diagram was prepared to show the general steps to dry and inert the Shippingport fuel loaded into SSFCs for transport and dry storage. Flow sheets have been prepared to show the flows and conditions for the various steps of the drying and inerting process. Calculations and data supporting the development of the flow sheets are included.

  8. Growth and development in inert non-aqueous liquids. [of higher plants

    NASA Technical Reports Server (NTRS)

    Siegel, S. M.

    1974-01-01

    A preview is presented of the survival and growth capabilities of higher plants in non-aqueous, inert liquids. The two media which were used are mineral (white) oil and fluorochemical inert liquid FC-75. Both liquids dissolve oxygen and carbon dioxide readily, but are insoluble in water. Consequently, plants submerged in these liquids are capable of gas exchange with the atmosphere, but possess a water impermeable coating the dimensions of which are determined by the size of the liquid holding container. In a sense, growing plants in a tank of mineral oil imparts on them a cuticle. Plants plus prescribed volumes of water were innoculated into mineral oil. Organisms with minimal water supplied could then be observed. Also, submersed plants covered with an oil slick were shown to be capable of growth in dessicating atmospheres.

  9. Models of bending strength for Gilsocarbon graphites irradiated in inert and oxidising environments

    NASA Astrophysics Data System (ADS)

    Eason, Ernest D.; Hall, Graham N.; Marsden, Barry J.; Heys, Graham B.

    2013-05-01

    This paper presents the development and validation of an empirical model of fast neutron damage and radiolytic oxidation effects on bending strength for the moulded Gilsocarbon graphites used in Advanced Gas-cooled Reactors (AGRs). The inert environment model is based on evidence of essentially constant strength as fast neutron dose increases in inert environment. The model of combined irradiation and oxidation calibrates that constant along with an exponential function representing the degree of radiolytic oxidation as measured by weight loss. The change in strength with exposure was found to vary from one AGR station to another. The model was calibrated to data on material trepanned from AGR moderator bricks after varying operating times.

  10. S1 certification of alpha-endosulfan, beta-endosulfan, and endosulfan sulfate in a candidate certified reference material (organochlorine pesticides in tea) by isotope dilution gas chromatography-mass spectrometry.

    PubMed

    Sin, Della Wai-Mei; Wong, Yee-Lok; Cheng, Eddie Chung-Chin; Lo, Man-Fung; Ho, Clare; Mok, Chuen-Shing; Wong, Siu-Kay

    2015-04-01

    This paper presents the certification of alpha-endosulfan, beta-endosulfan, and endosulfan sulfate in a candidate tea certified reference material (code: GLHK-11-03) according to the requirements of the ISO Guide 30 series. Certification of GLHK-11-03 was based on an analytical method purposely developed for the accurate measurement of the mass fraction of the target analytes in the material. An isotope dilution mass spectrometry (IDMS) method involving determination by (i) gas chromatography-negative chemical ionization-mass spectrometry (GC-NCI-MS) and (ii) gas chromatography-electron ionization-high-resolution mass spectrometry (GC-EI-HRMS) techniques was employed. The performance of the described method was demonstrated through participation in the key comparison CCQM-K95 "Mid-Polarity Analytes in Food Matrix: Mid-Polarity Pesticides in Tea" organized by the Consultative Committee for Amount of Substance-Metrology in Chemistry in 2012, where the study material was the same as the certified reference material (CRM). The values reported by using the developed method were in good agreement with the key comparison reference value (KCRV) assigned for beta-endosulfan (727?±?14 ?g kg(-1)) and endosulfan sulfate (505?±?11 ?g kg(-1)), where the degree of equivalence (DoE) values were 0.41 and 0.40, respectively. The certified values of alpha-endosulfan, beta-endosulfan, and endosulfan sulfate in dry mass fraction in GLHK-11-03 were 350, 730, and 502 ?g kg(-1), respectively, and the respective expanded uncertainties, due to sample inhomogeneity, long-term and short-term stability, and variability in the characterization procedure, were 27 ?g kg(-1) (7.8 %), 48 ?g kg(-1) (6.6 %), and 33 ?g kg(-1) (6.6 %). PMID:25619984

  11. On-line monitoring of benzene air concentrations while driving in traffic by means of isotopic dilution gas chromatography/mass spectrometry.

    PubMed

    Davoli, E; Cappellini, L; Moggi, M; Ferrari, S; Fanelli, R

    1996-01-01

    There is no shortage of information about the average benzene concentrations in urban air, but there is very little about microenvironmental exposure, such as in-vehicle concentrations while driving in various traffic conditions, while refuelling, or while in a parking garage. The main reason for this lack of data is that no analytical instrumentation has been available to measure on-line trace amounts of benzene in such situations. We have recently proposed a highly accurate, high-speed cryofocusing gas chromatography/mass spectrometry (GC/MS) system for monitoring benzene concentrations in air. Accuracy of the analytical data is achieved by enrichment of the air sample before trapping, with a stable isotope permeation tube system. The same principles have been applied to a new instrument, specifically designed for operation on an electric vehicle (Ducato Elettra, Fiat). The zero emission vehicle and the fully transportable, battery-operated GC/MS system provide a unique possibility of monitoring benzene exposure in real everyday situations such as while driving, refuelling, or repairing a car. All power consumptions have been reduced so as to achieve a battery-operated GC/MS system. Liquid nitrogen cryofocusing has been replaced by a packed, inductively heated, graphitized charcoal microtrap. The instrument has been mounted on shock absorbers and installed in the van. The whole system has been tested in both fixed and mobile conditions. The maximum monitoring period without external power supply is 6 h. The full analytical cycle is 4 min, allowing close to real-time monitoring, and the minimum detectable level is 1 microgram/m3 for benzene. In-vehicle monitoring showed that, when recirculation was off and ventilation on, i.e., air from outside the vehicle was blown inside, concentrations varied widely in different driving conditions: moving from a parking lot into normal traffic on an urban traffic condition roadway yielded an increase in benzene concentration from 17 to 62.3 micrograms/m3 even if the actual distance was small. A larger increase was observed when a car was left with the engine running at a distance 2 m from the zero emission vehicle: We measured an increment of benzene concentrations from 15.2 to 174.4 micrograms/m3 with a car equipped with a catalytic converter, and from 19.1 to 386.3 micrograms/m3 with a car without such a converter. PMID:8738357

  12. Technical basis for storage of Zircaloy-clad spent fuel in inert gases

    SciTech Connect

    Johnson, A.B. Jr.; Gilbert, E.R.

    1983-09-01

    This report summarizes the technical bases to establish safe conditions for dry storage of Zircaloy-clad fuel. Dry storage of fuel with zirconium alloy cladding has been licensed in Canada, the Federal Republic of Germany, and Switzerland. In addition, dry storage demonstrations, hot cell tests, and modeling have been conducted using Zircaloy-clad fuel. The demonstrations have included irradiated boiling water reactor, pressurized heavy-water reactor, and pressurized water reactor (PWR) fuel assemblies. Irradiated fuel has been emplaced in and retrieved from metal casks, dry wells, silos, and a vault. Dry storage tests and demonstrations have involved {similar_to}5,000 fuel rods, and {similar_to}600 rods have been monitored during dry storage in inert gases with maximum cladding temperatures ranging from 50 to 570{sup 0}C. Although some tests and demonstrations are still in progress, there is currently no evidence that any rods exposed to inert gases have failed (one PWR rod exposed to an air cover gas failed at {similar_to}70{sup 0}C). Based on this favorable experience, it is concluded that there is sufficient information on fuel rod behavior, storage conditions, and potential cladding failure mechanisms to support licensing of dry storage in the United States. This licensing position includes a requirement for inert cover gases and a maximum cladding temperature guideline of 380{sup 0}C for Zircaloy-clad fuel. Using an inert cover gas assures that even if fuel with cladding defects were placed in dry storage, or if defects develop during storage, the defects would not propagate. Tests and demonstrations involving Zircaloy-clad rods and assemblies with maximum cladding temperatures above 400{sup 0}C are in progress. When the results from these tests have been evaluated, the viability of higher temperature limits should be examined. Acceptable conditions for storage in air and dry storage of consolidated fuel are issues yet to be resolved.

  13. Novel type of tuned mass damper with inerter which enables changes of inertance

    NASA Astrophysics Data System (ADS)

    Brzeski, P.; Kapitaniak, T.; Perlikowski, P.

    2015-08-01

    In this paper we propose the novel type of tuned mass damper and investigate its properties. Characteristic feature of the device is that it contains a special type of inerter equipped with a continuously variable transmission and gear-ratio control system which enables stepless and accurate changes of inertance. We examine the damping properties of the proposed tuned mass damper with respect to one-degree-of-freedom harmonically forced oscillator. To prove the potential of introduced device we test its four different embodiments characterized by four different sets of parameters. We generalize our investigation and show that proposed device has broad spectrum of applications, we consider three different stiffness characteristics of damped structure i.e. linear, softening and hardening. We use the frequency response curves to present how considered devices influence the dynamics of analyzed systems and demonstrate their capabilities. Moreover, we check how small perturbations introduced to the system by parametric and additive noise influence system's dynamics. Numerical results show excellent level of vibration reduction in an extremely wide range of forcing frequencies.

  14. Inertance Tube Modeling and the Effects of Temperature

    NASA Astrophysics Data System (ADS)

    Dodson, C.; Razani, A.; Roberts, T.

    2010-04-01

    Pulse tube refrigerators (PTRs) have made dramatic improvements in reliability, efficiency and usage. Inertance tube PTRs have been one of the keys to these improvements. The inertance tube is the component in the PTR that most easily affects the control of the PTR fluid dynamics. In one application in multistage cryocoolers, the performance of inertance tubes at the cryogenic temperatures is of interest. One purpose of this paper is to understand how temperature and the size of the reservoir influence the phase shift between mass flow rate and pressure at the inlet of the inertance tube. Various models including a two dimensional Computational Fluid Dynamics (CFD) will be compared to understand how these models can predict the phase shift and the acoustic power.

  15. Inert electrodes program: Fiscal Year 1987 Annual Report

    SciTech Connect

    Koski, O.H.; Marschman, S.C.; Schilling, C.H.; Windisch, C.F.

    1988-12-01

    The Inert Electrodes Program is being conducted at the Pacific Northwest Laboratory (PNL) for the US Department of Energy (DOE), Office of Industrial Programs (OIP). The purpose of the program is to develop long-lasting, energy-efficient anodes, cathodes, and ancillary equipment for Hall-Heroult cells used by aluminum industry. The program is divided into three tasks with the following objectives: Inert Anode Development - to improve the energy efficiency of Hall-Heroult cells by development of inert anodes; Stable Cathode Studies - to develop methods for retrofitting Hall-Heroult cells with TiB/sub 2/-based cathode materials; and Sensor Development - to devise sensors to control the chemistry of Hall-Heroult Cells using stable anodes and cathodes. This Inert Electrodes Program annual report highlights the major technical accomplishment of FY 1987. The accomplishments are presented in the following sections: Management, Materials Development and Testing, Materials Evaluation, Stable Cathode Studies, and Sensor Development. 50 refs., 47 figs.

  16. 114. SMALL ARMS (BUILDINGS 9798) AND INERT STOREHOUSE (BLDGS. 1031040) ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    114. SMALL ARMS (BUILDINGS 97-98) AND INERT STOREHOUSE (BLDGS. 103-1040) PLAN AND ELEVATIONS, FULLER/SCOTT, MARCH 15, 1941. QP ACC 1791. - Quonset Point Naval Air Station, Roger Williams Way, North Kingstown, Washington County, RI

  17. Dilute magnetic semiconductor nanowires

    NASA Astrophysics Data System (ADS)

    Kulkarni, J. S.; Kazakova, O.; Holmes, J. D.

    2006-11-01

    Semiconductor materials form the basis of modern electronics, communication, data storage and computing technologies. One of today’s challenges for the development of future technologies is the realization of devices that control not only the electron charge, as in present electronics, but also its spin, setting the basis for future spintronics. Spintronics represents the concept of the synergetic and multifunctional use of charge and spin dynamics of electrons, aiming to go beyond the traditional dichotomy of semiconductor electronics and magnetic storage technology. The most direct method to induce spin-polarized electrons into a semiconductor is by introducing appropriate transition-metal or rare-earth dopants producing a dilute magnetic semiconductor (DMS). At the same time the seamless integration of future spintronic devices into nanodevices would require the fabrication of one-dimensional DMS nanostructures in well-defined architectures. In this review we focus on recent advances in the synthesis of DMS nanowires as well discussing the structural, optical and magnetic properties of these materials.

  18. Stress in dilute suspensions

    NASA Technical Reports Server (NTRS)

    Passman, Stephen L.

    1989-01-01

    Generally, two types of theory are used to describe the field equations for suspensions. The so-called postulated equations are based on the kinetic theory of mixtures, which logically should give reasonable equations for solutions. The basis for the use of such theory for suspensions is tenuous, though it at least gives a logical path for mathematical arguments. It has the disadvantage that it leads to a system of equations which is underdetermined, in a sense that can be made precise. On the other hand, the so-called averaging theory starts with a determined system, but the very process of averaging renders the resulting system underdetermined. A third type of theory is proposed in which the kinetic theory of gases is used to motivate continuum equations for the suspended particles. This entails an interpretation of the stress in the particles that is different from the usual one. Classical theory is used to describe the motion of the suspending medium. The result is a determined system for a dilute suspension. Extension of the theory to more concentrated systems is discussed.

  19. 40 CFR 1065.240 - Dilution air and diluted exhaust flow meters.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 2010-07-01 false Dilution air and diluted exhaust flow meters...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Measurements § 1065.240 Dilution air and diluted exhaust flow...

  20. 40 CFR 1065.240 - Dilution air and diluted exhaust flow meters.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 2014-07-01 false Dilution air and diluted exhaust flow meters...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Measurements § 1065.240 Dilution air and diluted exhaust flow...

  1. 40 CFR 1065.240 - Dilution air and diluted exhaust flow meters.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 2011-07-01 false Dilution air and diluted exhaust flow meters...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Measurements § 1065.240 Dilution air and diluted exhaust flow...

  2. 40 CFR 1065.240 - Dilution air and diluted exhaust flow meters.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 2012-07-01 false Dilution air and diluted exhaust flow meters...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Measurements § 1065.240 Dilution air and diluted exhaust flow...

  3. 40 CFR 1065.240 - Dilution air and diluted exhaust flow meters.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 2013-07-01 false Dilution air and diluted exhaust flow meters...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Measurements § 1065.240 Dilution air and diluted exhaust flow...

  4. Effects of radiative heat transfer on the turbulence structure in inert and reacting mixing layers

    NASA Astrophysics Data System (ADS)

    Ghosh, Somnath; Friedrich, Rainer

    2015-05-01

    We use large-eddy simulation to study the interaction between turbulence and radiative heat transfer in low-speed inert and reacting plane temporal mixing layers. An explicit filtering scheme based on approximate deconvolution is applied to treat the closure problem arising from quadratic nonlinearities of the filtered transport equations. In the reacting case, the working fluid is a mixture of ideal gases where the low-speed stream consists of hydrogen and nitrogen and the high-speed stream consists of oxygen and nitrogen. Both streams are premixed in a way that the free-stream densities are the same and the stoichiometric mixture fraction is 0.3. The filtered heat release term is modelled using equilibrium chemistry. In the inert case, the low-speed stream consists of nitrogen at a temperature of 1000 K and the highspeed stream is pure water vapour of 2000 K, when radiation is turned off. Simulations assuming the gas mixtures as gray gases with artificially increased Planck mean absorption coefficients are performed in which the large-eddy simulation code and the radiation code PRISSMA are fully coupled. In both cases, radiative heat transfer is found to clearly affect fluctuations of thermodynamic variables, Reynolds stresses, and Reynolds stress budget terms like pressure-strain correlations. Source terms in the transport equation for the variance of temperature are used to explain the decrease of this variance in the reacting case and its increase in the inert case.

  5. Effects of radiative heat transfer on the turbulence structure in inert and reacting mixing layers

    SciTech Connect

    Ghosh, Somnath; Friedrich, Rainer

    2015-05-15

    We use large-eddy simulation to study the interaction between turbulence and radiative heat transfer in low-speed inert and reacting plane temporal mixing layers. An explicit filtering scheme based on approximate deconvolution is applied to treat the closure problem arising from quadratic nonlinearities of the filtered transport equations. In the reacting case, the working fluid is a mixture of ideal gases where the low-speed stream consists of hydrogen and nitrogen and the high-speed stream consists of oxygen and nitrogen. Both streams are premixed in a way that the free-stream densities are the same and the stoichiometric mixture fraction is 0.3. The filtered heat release term is modelled using equilibrium chemistry. In the inert case, the low-speed stream consists of nitrogen at a temperature of 1000 K and the highspeed stream is pure water vapour of 2000 K, when radiation is turned off. Simulations assuming the gas mixtures as gray gases with artificially increased Planck mean absorption coefficients are performed in which the large-eddy simulation code and the radiation code PRISSMA are fully coupled. In both cases, radiative heat transfer is found to clearly affect fluctuations of thermodynamic variables, Reynolds stresses, and Reynolds stress budget terms like pressure-strain correlations. Source terms in the transport equation for the variance of temperature are used to explain the decrease of this variance in the reacting case and its increase in the inert case.

  6. Process and apparatus for igniting a burner in an inert atmosphere

    DOEpatents

    Coolidge, Dennis W. (Katy, TX); Rinker, Franklin G. (Perrysburg, OH)

    1994-01-01

    According to this invention there is provided a process and apparatus for the ignition of a pilot burner in an inert atmosphere without substantially contaminating the inert atmosphere. The process includes the steps of providing a controlled amount of combustion air for a predetermined interval of time to the combustor then substantially simultaneously providing a controlled mixture of fuel and air to the pilot burner and to a flame generator. The controlled mixture of fuel and air to the flame generator is then periodically energized to produce a secondary flame. With the secondary flame the controlled mixture of fuel and air to the pilot burner and the combustion air is ignited to produce a pilot burner flame. The pilot burner flame is then used to ignited a mixture of main fuel and combustion air to produce a main burner flame. The main burner flame then is used to ignite a mixture of process derived fuel and combustion air to produce products of combustion for use as an inert gas in a heat treatment process.

  7. Dilution refrigeration for space applications

    NASA Technical Reports Server (NTRS)

    Israelsson, U. E.; Petrac, D.

    1990-01-01

    Dilution refrigerators are presently used routinely in ground based applications where temperatures below 0.3 K are required. The operation of a conventional dilution refrigerator depends critically on the presence of gravity. To operate a dilution refrigerator in space many technical difficulties must be overcome. Some of the anticipated difficulties are identified in this paper and possible solutions are described. A single cycle refrigerator is described conceptually that uses forces other than gravity to function and the stringent constraints imposed on the design by requiring the refrigerator to function on the earth without using gravity are elaborated upon.

  8. Dilution physics modeling: Dissolution/precipitation chemistry

    SciTech Connect

    Onishi, Y.; Reid, H.C.; Trent, D.S.

    1995-09-01

    This report documents progress made to date on integrating dilution/precipitation chemistry and new physical models into the TEMPEST thermal-hydraulics computer code. Implementation of dissolution/precipitation chemistry models is necessary for predicting nonhomogeneous, time-dependent, physical/chemical behavior of tank wastes with and without a variety of possible engineered remediation and mitigation activities. Such behavior includes chemical reactions, gas retention, solids resuspension, solids dissolution and generation, solids settling/rising, and convective motion of physical and chemical species. Thus this model development is important from the standpoint of predicting the consequences of various engineered activities, such as mitigation by dilution, retrieval, or pretreatment, that can affect safe operations. The integration of a dissolution/precipitation chemistry module allows the various phase species concentrations to enter into the physical calculations that affect the TEMPEST hydrodynamic flow calculations. The yield strength model of non-Newtonian sludge correlates yield to a power function of solids concentration. Likewise, shear stress is concentration-dependent, and the dissolution/precipitation chemistry calculations develop the species concentration evolution that produces fluid flow resistance changes. Dilution of waste with pure water, molar concentrations of sodium hydroxide, and other chemical streams can be analyzed for the reactive species changes and hydrodynamic flow characteristics.

  9. Dark Matter with Topological Defects in the Inert Doublet Model

    E-print Network

    Mark Hindmarsh; Russell Kirk; Jose Miguel No; Stephen M. West

    2015-07-29

    We examine the production of dark matter by decaying topological defects in the high mass region $m_{\\mathrm{DM}} \\gg m_W$ of the Inert Doublet Model, extended with an extra U(1) gauge symmetry. The density of dark matter states (the neutral Higgs states of the inert doublet) is determined by the interplay of the freeze-out mechanism and the additional production of dark matter states from the decays of topological defects, in this case cosmic strings. These decays increase the predicted relic abundance compared to the standard freeze-out only case, and as a consequence the viable parameter space of the Inert Doublet Model can be widened substantially. In particular, for a given dark matter annihilation rate lower dark matter masses become viable. We investigate the allowed mass range taking into account constraints on the energy injection rate from the diffuse $\\gamma$-ray background and Big Bang Nucleosynthesis, together with constraints on the dark matter properties coming from direct and indirect detection limits. For the Inert Doublet Model high-mass region, an inert Higgs mass as low as $\\sim 200$ GeV is permitted. There is also an upper limit on string mass per unit length, and hence the symmetry breaking scale, from the relic abundance in this scenario. Depending on assumptions made about the string decays, the limits are in the range $10^{12}$ GeV to $10^{13}$ GeV.

  10. Effect of Using Inert and Non-Inert Gases on the Thermal Degradation and Fuel Properties of Biomass in the Torrefaction and Pyrolysis Region 

    E-print Network

    Eseltine, Dustin E.

    2012-02-14

    OF USING INERT AND NON-INERT GASES ON THE THERMAL DEGRADATION AND FUEL PROPERTIES OF BIOMASS IN THE TORREFACTION AND PYROLYSIS REGION A Thesis by DUSTIN E. ESELTINE Submitted to the Office of Graduate Studies of Texas A&M University... and Fuel Properties of Biomass in the Torrefaction and Pyrolysis Region Copyright 2011 Dustin E. Eseltine EFFECT OF USING INERT AND NON-INERT GASES ON THE THERMAL DEGRADATION AND FUEL PROPERTIES OF BIOMASS IN THE TORREFACTION AND PYROLYSIS...

  11. Praxair's dilute oxygen combustion technology for pyrometallurgical applications

    NASA Astrophysics Data System (ADS)

    Riley, M. F.; Kobayashi, H.; Deneys, A. C.

    2001-05-01

    Dilute oxygen combustion (DOC) technology uses separate high-velocity fuel and oxygen jets to generate strong in-furnace gas recirculation, producing combustion between the fuel and a highly diluted oxygen and furnace-gas mixture. These very low NOx oxy-fuel burners have been developed and commercially demonstrated in steel reheating furnaces. The burner design meets industry needs for increased productivity and lower operating costs with minimal capital expense and low maintenance. The performance of DOC technology has been measured under laboratory and industrial conditions encompassing both natural gas and coke oven gas firing, and a wide range of furnace temperatures and nitrogen levels that simulate air infiltration. This paper describes the results of the tests using natural gas as the fuel and lists potential applications for DOC technology in the non-ferrous metals industry.

  12. Neutronic aspects of inert matrix fuels for application in ADS

    NASA Astrophysics Data System (ADS)

    Wallenius, J.

    2003-07-01

    Accelerator driven systems may operate on uranium or thorium free fuels. In order to guarantee the stability of such fuels at high temperatures, the use of inert matrices is foreseen. In the present study, safety parameters of 800 MWth ADS cores operating on oxide and nitride fuels with high americium content are investigated for a representative range of pin and core geometries. It is shown that among the inert matrices investigated, chromium yields the lowest void worth, hafnium nitride the highest fission probability for americium and magnesia the highest burnup potential.

  13. Comprehensive two-dimensional gas chromatography with isotope dilution time-of-flight mass spectrometry for the measurement of dioxins and polychlorinated biphenyls in foodstuffs. Comparison with other methods.

    PubMed

    Focant, Jean-François; Eppe, Gauthier; Scippo, Marie-Louise; Massart, Anne-Cécile; Pirard, Catherine; Maghuin-Rogister, Guy; De Pauw, Edwin

    2005-09-01

    A comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC x GC-TOF-MS) experimental setup was tested for the measurement of seven 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs), ten 2,3,7,8-substituted polychlorinated dibenzofurans (PCDFs), four non-ortho-polychlorinated biphenyls (PCBs), eight mono-ortho-PCBs, and six indicator PCBs (Aroclor 1260) in foodstuff samples. A 40m RTX-500 (0.18mm I.D., 0.10 microm df) was used as the first dimension (1D) and a 1.5 m BPX-50 (0.10mm I.D., 0.10 microm df) as the second dimension (2D). The GC x GC chromatographic separation was completed in 45 min. Quantification was performed using 13C-label isotope dilution (ID). Isotope ratios of the selected quantification ions were checked against theoretical values prior to peak assignment and quantification. The dynamic working range spanned three orders of magnitude. The lowest detectable amount of 2,3,7,8-TCDD was 0.2 pg. Fish, pork, and milk samples were considered. On a congener basis, the GC x GC-ID-TOF-MS method was compared to the reference GC-ID high resolution mass spectrometry (HRMS) method and to the alternative GC-ID tandem-in-time quadrupole ion storage mass spectrometry (QIST-MS/MS). PCB levels ranged from low picogram (pg) to low nanogram (ng) per gram of sample and data compared very well between the different methods. For all matrices, PCDD/Fs were at a low pg level (0.05-3 pg) on a fresh weight basis. Although congener profiles were accurately described, RSDs of GC x GC-ID-TOF-MS and GC-QIST-MS/MS were much higher than for GC-ID-HRMS, especially for low level pork and milk. On a toxic equivalent (TEQ) basis, all methods, including the dioxin-responsive chemically activated luciferase gene expression (DR-CALUX) assay, produced similar responses. A cost comparison is also presented. PMID:16130655

  14. Dilute Oxygen Combustion Phase 3 Final Report

    SciTech Connect

    Riley, M.F.; Ryan, H.M.

    2000-05-31

    Dilute Oxygen Combustion (DOC) burners have been successfully installed and operated in the reheat furnace at Auburn Steel Co., Inc., Auburn, NY, under Phase 3 of the Dilute Oxygen Combustion project. Two new preheat zones were created employing a total of eight 6.5 MMBtu/hr capacity burners. The preheat zones provide a 30 percent increase in maximum furnace production rate, from 75 tph to 100 tph. The fuel rate is essentially unchanged, with the fuel savings expected from oxy-fuel combustion being offset by higher flue gas temperatures. When allowance is made for the high nitrogen level and high gas phase temperature in the furnace, measured NOx emissions are in line with laboratory data on DOC burners developed in Phase 1 of the project. Burner performance has been good and there have been no operating or maintenance problems. The DOC system continues to be used as part of Auburn Steel?s standard reheat furnace practice. High gas phase temperature is a result of the high firing density needed to achieve high production rates, and little opportunity exists for improvement in that area. However, fuel and NOx performance can be improved by further conversion of furnace zones to DOC burners, which will lower furnace nitrogen levels. Major obstacles are cost and concern about increased formation of oxide scale on the steel. Oxide scale formation may be enhanced by exposure of the steel to higher concentrations of oxidizing gas components (primarily products of combustion) in the higher temperature zones of the furnace. Phase 4 of the DOC project will examine the rate of oxide scale formation in these higher temperature zones and develop countermeasures that will allow DOC burners to be used successfully in these furnace zones.

  15. Dilute Oxygen Combustion - Phase 3 Report

    SciTech Connect

    Riley, Michael F.

    2000-05-31

    Dilute Oxygen Combustion (DOC) burners have been successfully installed and operated in the reheat furnace at Auburn Steel Co., Inc., Auburn, NY, under Phase 3 of the Dilute Oxygen Combustion project. Two new preheat zones were created employing a total of eight 6.5 MMBtu/hr capacity burners. The preheat zones provide a 30 percent increase in maximum furnace production rate, from 75 tph to 100 tph. The fuel rate is essentially unchanged, with the fuel savings expected from oxy-fuel combustion being offset by higher flue gas temperatures. When allowance is made for the high nitrogen level and high gas phase temperature in the furnace, measured NOx emissions are in line with laboratory data on DOC burners developed in Phase 1 of the project. Burner performance has been good, and there have been no operating or maintenance problems. The DOC system continues to be used as part of Auburn Steel's standard reheat furnace practice. High gas phase temperature is a result of the high firing density needed to achieve high production rates, and little opportunity exists for improvement in that area. However, fuel and NOx performance can be improved by further conversion on furnace zones to DOC burners, which will lower furnace nitrogen levels. Major obstacles are cost and concern about increased formation of oxide scale on the steel. Oxide scale formation may be enhanced by exposure of the steel to higher concentrations of oxidizing gas components (primarily products of combustion) in the higher temperature zones of the furnace. Phase 4 of the DOC project will examine the rate of oxide scale formation in these higher temperature zones and develop countermeasures that will allow DOC burners to be used successfully in these furnace zones.

  16. Critical Thinking: Inert Information, Activated Ignorance, and Activated Knowledge.

    ERIC Educational Resources Information Center

    Paul, Richard; Elder, Linda

    2001-01-01

    Suggests that there are three ways of taking in information: internalizing inert information, forming activated ignorance, or achieving activated knowledge. Explains that only activated knowledge leads the learner, by implication, to more knowledge, and that seeking the logic of things can lead to discovery of activated knowledge. (NB)

  17. Inert Electrodes Program fiscal year 1988 annual report

    SciTech Connect

    Strachan, D.M.; Marschman, S.C.; Davis, N.C.; Friley, J.R.; Schilling, C.H.

    1989-10-01

    The Inert Electrodes Program, being conducted by Pacific Northwest Laboratory (PNL), involves improving the Hall-Heroult cells used by the Aluminum Industry for the electrochemical production of aluminum. The PNL research centers on developing more energy efficient, longer-lasting anodes and cathodes and ancillary equipment. Major accomplishments for Fiscal Year 1988 are summarized below. 14 refs., 56 figs., 9 tabs.

  18. Determination of Ethane-1,2-diamine in Inert Complexes.

    ERIC Educational Resources Information Center

    Searle, Graeme H.

    1985-01-01

    Describes a procedure for determining ethane-1,2-diamine (EN) which is generally applicable for inert or labile complexes or for EN in its salts, although it cannot be used directly with ammonium or coordinated ammonia. It gives results with five percent accuracy or better and requires less than one hour laboratory time. (JN)

  19. Control of Charge Dilution in Turbocharged Diesel Engines via Exhaust Valve Timing

    E-print Network

    Stefanopoulou, Anna

    Control of Charge Dilution in Turbocharged Diesel Engines via Exhaust Valve Timing Hakan Yilmaz Gas Recirculation (iEGR) or charge dilution in Diesel engines. We develop a crankangle based dynamic nonlinear model of a six-cylinder 12 liter turbocharged (TC) Diesel engine. This model captures

  20. Gas shielding apparatus

    DOEpatents

    Brandt, D.

    1984-06-05

    An apparatus for preventing oxidation by uniformly distributing inert shielding gas over the weld area of workpieces such as pipes being welded together. The apparatus comprises a chamber and a gas introduction element. The chamber has an annular top wall, an annular bottom wall, an inner side wall and an outer side wall connecting the top and bottom walls. One side wall is a screen and the other has a portion defining an orifice. The gas introduction element has a portion which encloses the orifice and can be one or more pipes. The gas introduction element is in fluid communication with the chamber and introduces inert shielding gas into the chamber. The inert gas leaves the chamber through the screen side wall and is dispersed evenly over the weld area.

  1. Gas shielding apparatus

    DOEpatents

    Brandt, D.

    1985-12-31

    An apparatus is disclosed for preventing oxidation by uniformly distributing inert shielding gas over the weld area of workpieces such as pipes being welded together. The apparatus comprises a chamber and a gas introduction element. The chamber has an annular top wall, an annular bottom wall, an inner side wall and an outer side wall connecting the top and bottom walls. One side wall is a screen and the other has a portion defining an orifice. The gas introduction element has a portion which encloses the orifice and can be one or more pipes. The gas introduction element is in fluid communication with the chamber and introduces inert shielding gas into the chamber. The inert gas leaves the chamber through the screen side wall and is dispersed evenly over the weld area. 3 figs.

  2. Explosion propagation in inert porous media.

    PubMed

    Ciccarelli, G

    2012-02-13

    Porous media are often used in flame arresters because of the high surface area to volume ratio that is required for flame quenching. However, if the flame is not quenched, the flow obstruction within the porous media can promote explosion escalation, which is a well-known phenomenon in obstacle-laden channels. There are many parallels between explosion propagation through porous media and obstacle-laden channels. In both cases, the obstructions play a duel role. On the one hand, the obstruction enhances explosion propagation through an early shear-driven turbulence production mechanism and then later by shock-flame interactions that occur from lead shock reflections. On the other hand, the presence of an obstruction can suppress explosion propagation through momentum and heat losses, which both impede the unburned gas flow and extract energy from the expanding combustion products. In obstacle-laden channels, there are well-defined propagation regimes that are easily distinguished by abrupt changes in velocity. In porous media, the propagation regimes are not as distinguishable. In porous media the entire flamefront is affected, and the effects of heat loss, turbulence and compressibility are smoothly blended over most of the propagation velocity range. At low subsonic propagation speeds, heat loss to the porous media dominates, whereas at higher supersonic speeds turbulence and compressibility are important. This blending of the important phenomena results in no clear transition in propagation mechanism that is characterized by an abrupt change in propagation velocity. This is especially true for propagation velocities above the speed of sound where many experiments performed with fuel-air mixtures show a smooth increase in the propagation velocity with mixture reactivity up to the theoretical detonation wave velocity. PMID:22213663

  3. Inert Gas Buffered Milling and Particle Size Separation of ���������������¯������������������������������­m-Scale Superconducting Precursor Powders - Final Report

    SciTech Connect

    P. McIntyre and S. Seshadri

    2008-06-20

    The project developed an aerosol system for the met milling and particle size separation of the precursor powders used in fabrication of powder-in-tube superconductors. The work builds upon the results of a previous SBIR-funded development that proved the basic principles of the virtual impactor (VI) technology and its efficacy for the powders of interest. The new project extended that work in three respects: it integrated provisions for recirculating the aerosol flow using inert gas to avoid contamination from O2, CO2 and water in ambient air; a quad configuration of VI subassemblies to support kg/hr throughput; and it incorporated design features that eliminate error trajectories which would introduce trace contamination of larger particles into the separated flow. The project demonstrated the technical effectiveness of the process and established its economic feasibility by achieving kg/hr throughput within a cost profile that would be profitable within the range of competitive toll fees. The project is beneficial to the public through its potential to improve the performance of superconducting materials for research and for biomedicine. It also conveys potential benefits for powders used in high-performance ceramics (for example for engines for automobiles and for aircraft) and for high-performance electrical insulators for telecommunications circuitry.

  4. Effects of dilution on fine particle mass and partitioning of semivolatile organics in diesel exhaust and wood smoke.

    PubMed

    Lipsky, Eric M; Robinson, Allen L

    2006-01-01

    Experiments were conducted to examine the effects of dilution on fine particle mass emissions from a diesel engine and wood stove. Filter measurements were made simultaneously using three dilution sampling systems operating at dilution ratios ranging from 20:1 to 510:1. Denuders and backup filters were used to quantify organic sampling artifacts. For the diesel engine operating at low load and wood combustion, large decreases in fine particle mass emissions were observed with increases in dilution. For example, the PM2.5 mass emission rate from a diesel engine operating at low load decreased by 50% when the dilution ratio was increased from 20:1 to 350:1. Measurements of organic and elemental carbon indicate that the changes in fine particle mass with dilution are caused by changes in partitioning of semivolatile organic compounds. At low levels of dilution semivolatile species largely occur in the particle phase, but increasing dilution reduces the concentration of semivolatile species, shifting this material to the gas phase in order to maintain phase equilibrium. Emissions of elemental carbon do not vary with dilution. Organic sampling artifacts are shown to vary with dilution because of the combination of changes in partitioning coupled with adsorption of gas-phase organics by quartz filters. The fine particle mass emissions from the diesel engine operating at medium load did not vary with dilution because of the lower emissions of semivolatile material and higher emissions of elemental carbon. To measure partitioning of semivolatile materials under atmospheric conditions, partitioning theory indicates that dilution samplers need to be operated such that the diluted exhaust achieves atmospheric levels of dilution. Too little dilution can potentially overestimate the fine particle mass emissions, and too much dilution (with clean air) can underestimate them. PMID:16433346

  5. Influence of inert gases on the reactive high power pulsed magnetron sputtering process of carbon-nitride thin films

    SciTech Connect

    Schmidt, Susann; Czigany, Zsolt; Greczynski, Grzegorz; Jensen, Jens; Hultman, Lars

    2013-01-15

    The influence of inert gases (Ne, Ar, Kr) on the sputter process of carbon and carbon-nitride (CN{sub x}) thin films was studied using reactive high power pulsed magnetron sputtering (HiPIMS). Thin solid films were synthesized in an industrial deposition chamber from a graphite target. The peak target current during HiPIMS processing was found to decrease with increasing inert gas mass. Time averaged and time resolved ion mass spectroscopy showed that the addition of nitrogen, as reactive gas, resulted in less energetic ion species for processes employing Ne, whereas the opposite was noticed when Ar or Kr were employed as inert gas. Processes in nonreactive ambient showed generally lower total ion fluxes for the three different inert gases. As soon as N{sub 2} was introduced into the process, the deposition rates for Ne and Ar-containing processes increased significantly. The reactive Kr-process, in contrast, showed slightly lower deposition rates than the nonreactive. The resulting thin films were characterized regarding their bonding and microstructure by x-ray photoelectron spectroscopy and transmission electron microscopy. Reactively deposited CN{sub x} thin films in Ar and Kr ambient exhibited an ordering toward a fullerene-like structure, whereas carbon and CN{sub x} films deposited in Ne atmosphere were found to be amorphous. This is attributed to an elevated amount of highly energetic particles observed during ion mass spectrometry and indicated by high peak target currents in Ne-containing processes. These results are discussed with respect to the current understanding of the structural evolution of a-C and CN{sub x} thin films.

  6. Application of Cryocoolers to a Vintage Dilution Refrigerator

    SciTech Connect

    Schmitt, Richard; Smith, Gary; Ruschman, Mark; Beaty, Jim; /Minnesota U.

    2011-06-06

    A dilution refrigerator is required for 50mK detector operation of CDMS (Cryogenic Dark Matter Search). Besides shielding the dilution refrigerator itself, the liquid nitrogen shield and liquid helium bath in the refrigerator cool the detector cryostat heat shields and cool electronics, resulting in significant external heat loads at 80K and at 4K. An Oxford Instruments Kelvinox 400 has served this role for ten years but required daily transfers of liquid nitrogen and liquid helium. Complicating the cryogen supply is the location 800 meters below ground in an RF shielded, class 10000 clean room at Soudan, MN. Nitrogen and helium re-liquefiers using cryocoolers were installed outside the clean room and continuously condense room temperature gas and return the liquids to the dilution refrigerator through a transfer line. This paper will describe the design, installation, controls and performance of liquefaction systems.

  7. Quantitative Analysis by Isotopic Dilution Using Mass Spectroscopy: The Determination of Caffeine by GC-MS.

    ERIC Educational Resources Information Center

    Hill, Devon W.; And Others

    1988-01-01

    Describes a laboratory technique for quantitative analysis of caffeine by an isotopic dilution method for coupled gas chromatography-mass spectroscopy. Discusses caffeine analysis and experimental methodology. Lists sample caffeine concentrations found in common products. (MVL)

  8. Mobile Melt-Dilute Treatment for Russian Spent Nuclear Fuel

    SciTech Connect

    Peacock, H.

    2002-09-17

    Treatment of spent Russian fuel using a Melt-Dilute (MD) process is proposed to consolidate fuel assemblies into a form that is proliferation resistant and provides critically safety under storage and disposal configurations. Russian fuel elements contain a variety of fuel meat and cladding materials. The Melt-Dilute treatment process was initially developed for aluminum-based fuels so additional development is needed for several cladding and fuel meat combinations in the Russian fuel inventory (e.g. zirconium-clad, uranium-zirconium alloy fuel). A Mobile Melt-Dilute facility (MMD) is being proposed for treatment of spent fuels at reactor site storage locations in Russia; thereby, avoiding the costs of building separate treatment facilities at each site and avoiding shipment of enriched fuel assemblies over the road. The MMD facility concept is based on laboratory tests conducted at the Savannah River Technology Center (SRTC), and modular pilot-scale facilities constructed at the Savannah River Site for treatment of US spent fuel. SRTC laboratory tests have shown the feasibility of operating a Melt-Dilute treatment process with either a closed system or a filtered off-gas system. The proposed Mobile Melt-Dilute process is presented in this paper.

  9. 75 FR 282 - Restricting the Mailing of Replica or Inert Explosive Devices

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-05

    ...Restricting the Mailing of Replica or Inert Explosive Devices AGENCY: Postal Service TM...allow for the mailing of replica or inert explosive devices, such as grenades, be sent...identify these items as ``replica or inert explosive devices'' rather than ``replica...

  10. Reduced temperature aluminum production in an electrolytic cell having an inert anode

    DOEpatents

    Dawless, Robert K. (Monroeville, PA); Ray, Siba P. (Murrysville, PA); Hosler, Robert B. (Sarver, PA); Kozarek, Robert L. (Apollo, PA); LaCamera, Alfred F. (Trafford, PA)

    2000-01-01

    Aluminum is produced by electrolytic reduction of alumina in a cell having a cathode, an inert anode and a molten salt bath containing metal fluorides and alumina. The inert anode preferably contains copper, silver and oxides of iron and nickel. Reducing the molten salt bath temperature to about 900-950.degree. C. lowers corrosion on the inert anode constituents.

  11. Problem of nature of inert gases in lunar surface material

    NASA Technical Reports Server (NTRS)

    Levskiy, L. K.

    1974-01-01

    The origin of isotopes of inert gases in lunar surface material was investigated from the standpoint of the isotopic two-component status of inert gases in the solar system. Helium and neon represent the solar wind component, while krypton and xenon are planetary gases. Type A gases are trapped by the material of the regolith in the early stages of the existence of the solar system and were brought to the lunar surface together with dust. The material of the regolith therefore cannot be considered as the product of the erosion of the crystalline rocks of the moon and in this sense are extralunar. The regolith material containing type A gases must be identified with the high temperature minerals of the carbonaceous chondrites.

  12. Evolution of weak disturbances in inert binary mixtures

    NASA Technical Reports Server (NTRS)

    Rasmussen, M. L.

    1977-01-01

    The evolution of weak disturbances in inert binary mixtures is determined for the one-dimensional piston problem. The interaction of the dissipative and nonlinear mechanisms is described by Burgers' equation. The binary mixture diffusion mechanisms enter as an additive term in an effective diffusivity. Results for the impulsive motion of a piston moving into an ambient medium and the sinusoidally oscillating piston are used to illustrate the results and elucidate the incorrect behavior pertaining to the associated linear theory.

  13. The Optimum Plutonium Inert Matrix Fuel Form for Reactor-Based Plutonium Disposition

    SciTech Connect

    Tulenko, J.S.; Wang, J.; Acosta, C.

    2004-10-03

    The University of Florida has underway an ongoing research program to validate the economic, operational and performance benefits of developing an inert matrix fuel (IMF) for the disposition of the U.S. weapons plutonium (Pu) and for the recycle of reprocessed Pu. The current fuel form of choice for Pu disposition for the Department of Energy is as a mixed oxide (MOX) (PuO2/UO2). We will show analyses that demonstrate that a Silicon Carbide (SiC) IMF offers improved performance capabilities as a fuel form for Pu recycle and disposition. The reason that UF is reviewing various materials to serve as an inert matrix fuel is that an IMF fuel form can offer greatly reduced Pu and transuranic isotope (TRU) production and also improved thermal performance characteristics. Our studies showed that the Pu content is reduced by an order of magnitude while centerline fuel temperatures are reduced approximately 380 degrees centigrade compared to MOX. These reduced temperatures result in reduced stored heat and thermal stresses in the pellet. The reduced stored heat reduces the consequences of the loss of coolant accident, while the reduced temperatures and thermal stresses yield greatly improved fuel performance. Silicon Carbide is not new to the nuclear industry, being a basic fuel material in gas cooled reactors.

  14. The Optimum Plutonium Inert Matrix Fuel Form for Reactor-Based Plutonium Disposition

    SciTech Connect

    Tulenko, J.S.; Wang, J.; Acosta, C.

    2004-10-06

    The University of Florida has underway an ongoing research program to validate the economic, operational and performance benefits of developing an inert matrix fuel (IMF) for the disposition of the U.S. weapons plutonium (Pu) and for the recycle of reprocessed Pu. The current fuel form of choice for Pu disposition for the Department of Energy is as a mixed oxide (MOX) (PuO2/UO2). We will show analyses that demonstrate that a Silicon Carbide (SiC) IMF offers improved performance capabilities as a fuel form for Pu recycle and disposition. The reason that UF is reviewing various materials to serve as an inert matrix fuel is that an IMF fuel form can offer greatly reduced Pu and transuranic isotope (TRU) production and also improved thermal performance characteristics. Our studies showed that the Pu content is reduced by an order of magnitude while centerline fuel temperatures are reduced approximately 380 degrees centigrade compared to MOX. These reduced temperatures result in reduced stored heat and thermal stresses in the pellet. The reduced stored heat reduces the consequences of the loss of coolant accident, while the reduced temperatures and thermal stresses yield greatly improved fuel performance. Silicon Carbide is not new to the nuclear industry, being a basic fuel material in gas cooled reactors.

  15. Kinetics of switch grass pellet thermal decomposition under inert and oxidizing atmospheres.

    PubMed

    Chandrasekaran, Sriraam R; Hopke, Philip K

    2012-12-01

    Grass pellets are a renewable resource that have energy content similar to that of wood. However, the higher ash and chlorine content affects combustion. Thermal degradation analysis of a fuel is useful in developing effective combustion. Thermogravimetric analysis (TGA) of the thermal degradation of grass pellets under inert (nitrogen) and oxidizing (air) atmospheres was conducted. Non-isothermal conditions were employed with 4 different heating rates. Kinetic parameters (activation energy and pre-exponential factors) were estimated using the iso-conversional method. Both pyrolysis and oxidative atmospheric thermal degradation exhibited two major loss process: volatilization of cellulose, hemicelluloses and lignin and burning or slow oxidation of the residual char. The activation energy and pre-exponential factors were high for the oxidizing environment. During pyrolysis, major decomposition occurred with 40% to 75% conversion of the mass to gas with an activation energy of 314 kJ/mol. In air the decomposition occurred with 30% to 55% conversion with an activation energy of 556 kJ/mol. There was a substantial effect of heating rate on mass loss and mass loss rate. The TG shifted to higher temperature ranges on increasing the heating rate. In both pyrolyzing and oxidizing conditions, average combustion and devolatilization rates increased. Enhanced combustion takes place with higher activation energy in oxidizing atmosphere compared to the inert atmosphere due to presence of air. PMID:23026316

  16. Science Notes: Dilution of a Weak Acid

    ERIC Educational Resources Information Center

    Talbot, Christopher; Wai, Chooi Khee

    2014-01-01

    This "Science note" arose out of practical work involving the dilution of ethanoic acid, the measurement of the pH of the diluted solutions and calculation of the acid dissociation constant, K[subscript a], for each diluted solution. The students expected the calculated values of K[subscript a] to be constant but they found that the…

  17. Investigation on the Inertance Tubes of Pulse Tube Cryocooler Without Reservoir

    NASA Astrophysics Data System (ADS)

    Liu, Y. J.; Yang, L. W.; Liang, J. T.; Hong, G. T.

    2010-04-01

    Phase angle is of vital importance for high-efficiency pulse tube cryocoolers (PTCs). Inertance tube as the main phase shifter is useful for the PTCs to obtain appropriate phase angle. Experiments of inertance tube without reservoir under variable frequency, variable length and diameter of inertance tube and variable pressure amplitude are investigated respectively. In addition, the authors used DeltaEC, a computer program to predict the performance of low-amplitude thermoacoustic engines, to simulate the effects of inertance tube without reservoir. According to the comparison of experiments and theoretical simulations, DeltaEC method is feasible and effective to direct and improve the design of inertance tubes.

  18. Heavy-Duty Waste Hauler with Chemically Correct Natural Gas Engine Diluted with EGR and Using a Three-Way Catalyst: Final Report, 24 February 2004 -- 23 February 2006

    SciTech Connect

    Reppert, T.; Chiu, J.

    2005-09-01

    This report discusses the development of a E7G 12-liter, lean-burn natural gas engine--using stoichiometric combustion, cooled exhaust gas recirculation, and three-way catalyst technologies--for refuse haulers.

  19. Thermal Conductivity and Sound Attenuation in Dilute Atomic Fermi Gases

    E-print Network

    Braby, Matt; Schaefer, Thomas

    2010-01-01

    We compute the thermal conductivity and sound attenuation length of a dilute atomic Fermi gas in the framework of kinetic theory. Above the critical temperature for superfluidity, T_c, the quasi-particles are fermions, whereas below T_c, the dominant excitations are phonons. We calculate the thermal conductivity in both cases. We find that at unitarity the thermal conductivity \\kappa in the normal phase scales as \\kappa ~ T^{3/2}. In the superfluid phase we find \\kappa ~ T^{2}. At high temperature the Prandtl number, the ratio of the momentum and thermal diffusion constants, is 2/3. The ratio increases as the temperature is lowered. As a consequence we expect sound attenuation in the normal phase just above T_c to be dominated by shear viscosity. We comment on the possibility of extracting the shear viscosity of the dilute Fermi gas at unitarity using measurements of the sound absorption length.

  20. Thermal Conductivity and Sound Attenuation in Dilute Atomic Fermi Gases

    E-print Network

    Matt Braby; Jingyi Chao; Thomas Schaefer

    2010-10-15

    We compute the thermal conductivity and sound attenuation length of a dilute atomic Fermi gas in the framework of kinetic theory. Above the critical temperature for superfluidity, T_c, the quasi-particles are fermions, whereas below T_c, the dominant excitations are phonons. We calculate the thermal conductivity in both cases. We find that at unitarity the thermal conductivity \\kappa in the normal phase scales as \\kappa ~ T^{3/2}. In the superfluid phase we find \\kappa ~ T^{2}. At high temperature the Prandtl number, the ratio of the momentum and thermal diffusion constants, is 2/3. The ratio increases as the temperature is lowered. As a consequence we expect sound attenuation in the normal phase just above T_c to be dominated by shear viscosity. We comment on the possibility of extracting the shear viscosity of the dilute Fermi gas at unitarity using measurements of the sound absorption length.

  1. Effect of Inert, Reducing, and Oxidizing Atmospheres on Friction and Wear of Metals to 1000 F

    NASA Technical Reports Server (NTRS)

    Buckley, Donald H.; Johnson, Robert L.

    1961-01-01

    Experiments were conducted in inert, reducing, and oxidizing atmospheres to determine their influence on the friction and wear properties of various metals. Nitrogen, argon, forming gas (10 volume percent H2, 90 volume percent N2), and various concentrations of oxygen in nitrogen were used. A 3/16-inch-radius hemispherical rider under a load of 1000 grams contacted the flat surface of a rotating disk. The surface speed employed was 35 feet per minute. The presence of surface oxides is vitally important to the protection of metals in sliding contact. Extremely high friction and excessive wear were encountered in the absence of these oxides. In some instances (electrolytically pure copper), the removal of the surface oxides resulted in mass welding of the specimens in sliding contact. Extremely small quantities of oxygen are sufficient to provide protection of metal surfaces; for example, with 440-C stainless steel, 0.03 volume percent oxygen was found to be adequate.

  2. Extraordinary temperature dependence of isochoric thermal conductivity of crystalline CO2 doped with inert gases

    NASA Astrophysics Data System (ADS)

    Konstantinov, V. A.; Manzhelii, V. G.; Revyakin, V. P.; Sagan, V. V.

    2006-11-01

    The isochoric thermal conductivities of the solid solutions (CO2)0.905Kr0.095 and (CO2)1-xXex (x =0.052 and 0.097) of different densities are investigated in the temperature interval from 150K to the onset of melting. An unusual effect of point defects on the thermal conductivity has been detected. In pure CO2 at T >150K the isochoric thermal conductivity decreases smoothly with increasing temperature. In contrast, the thermal conductivity of CO2/Kr and CO2/Xe solid solutions first decreases, passing through a minimum at 200-210K, and then starts to increase with temperature up to the onset of melting. This behavior of the isochoric thermal conductivity is attributed to the rotation of the CO2 molecules, which gain more freedom as the spherically symmetrical inert gas atoms are dissolved in the CO2.

  3. Development of a compact dilution refrigerator for zero gravity operation

    NASA Technical Reports Server (NTRS)

    Roach, Pat R.; Helvensteijn, Ben

    1990-01-01

    A compact dilution refrigerator design based on internal charcoal adsorption is being tested for operation in zero gravity. This refrigerator is self-contained with no external pumps or gas handling system and provides reliable operation since it has no moving parts. All operations are performed with heaters and are completely computer controlled. The refrigerator is capable of providing many hours of operation at very low temperature before the charcoal pumps must be recycled.

  4. Neutrophils Generate Microparticles during Exposure to Inert Gases Due to Cytoskeletal Oxidative Stress*

    PubMed Central

    Thom, Stephen R.; Bhopale, Veena M.; Yang, Ming

    2014-01-01

    This investigation was to elucidate the mechanism for microparticle (MP) formation triggered by exposures to high pressure inert gases. Human neutrophils generate MPs at a threshold of ?186 kilopascals with exposures of 30 min or more. Murine cells are similar, but MP production occurs at a slower rate and continues for ?4 h, whether or not cells remain under pressure. Neutrophils exposed to elevated gas but not hydrostatic pressure produce MPs according to the potency series: argon ? nitrogen > helium. Following a similar pattern, gases activate type-2 nitric-oxide synthase (NOS-2) and NADPH oxidase (NOX). MP production does not occur with neutrophils exposed to a NOX inhibitor (Nox2ds) or a NOS-2 inhibitor (1400W) or with cells from mice lacking NOS-2. Reactive species cause S-nitrosylation of cytosolic actin that enhances actin polymerization. Protein cross-linking and immunoprecipitation studies indicate that increased polymerization occurs because of associations involving vasodilator-stimulated phosphoprotein, focal adhesion kinase, the H+/K+ ATPase ? (flippase), the hematopoietic cell multidrug resistance protein ABC transporter (floppase), and protein-disulfide isomerase in proximity to short actin filaments. Using chemical inhibitors or reducing cell concentrations of any of these proteins with small inhibitory RNA abrogates NOS-2 activation, reactive species generation, actin polymerization, and MP production. These effects were also inhibited in cells exposed to UV light, which photoreverses S-nitrosylated cysteine residues and by co-incubations with the antioxidant ebselen or cytochalasin D. The autocatalytic cycle of protein activation is initiated by inert gas-mediated singlet O2 production. PMID:24867949

  5. Detailed Studies on Flame Extinction by Inert Particles in Normal- and Micro-gravity

    NASA Technical Reports Server (NTRS)

    Andac, M. G.; Egolfopoulos, F. N.; Campbell, C. S.

    2001-01-01

    The combustion of dusty flows has been studied to lesser extent than pure gas phase flows and sprays. Particles can have a strong effect by modifying the dynamic response and detailed structure of flames through the dynamic, thermal, and chemical couplings between the two phases. A rigorous understanding of the dynamics and structure of two-phase flows can be attained in stagnation flow configurations, which have been used by others to study spray combustion as well as reacting dusty flows. In earlier studies on reacting dusty flows, the thermal coupling between the two phases as well as the effect of gravity on the flame response were not considered. However, in Ref. 6, the thermal coupling between chemically inert particles and the gas was addressed in premixed flames. The effects of gravity was also studied showing that it can substantially affect the profiles of the particle velocity, number density, mass flux, and temperature. The results showed a strong dynamic and thermal dependence of reacting dusty flows to particle number density. However, the work was only numerical and limited to twin-flames, stagnation, premixed flames. In Ref. 7 the effects of chemically inert particle clouds on the extinction of strained premixed and non-premixed flames were studied both experimentally and numerically at 1-g. It was shown and explained that large particles can cause more effective flame cooling compared to smaller particles. The effects of flame configuration and particle injection orientation were also addressed. The complexity of the coupling between the various parameters in such flows was demonstrated and it was shown that it was impossible to obtain a simple and still meaningful scaling that captured all the pertinent physics.

  6. An electromagnetic inerter-based vibration suppression device

    NASA Astrophysics Data System (ADS)

    Gonzalez-Buelga, A.; Clare, L. R.; Neild, S. A.; Jiang, J. Z.; Inman, D. J.

    2015-05-01

    This paper describes how an inerter-based device for structural vibration suppression can be realized using an electromagnetic transducer such as a linear motor. When the motor shaft moves, a difference of voltage is generated across the transducer coil. The voltage difference is proportional to the relative velocity between its two terminals. The electromagnetic transducer will exert a force proportional to current following the Lorentz principle if the circuit is closed around the transducer coil. If an electronic circuit consisting of a capacitor, an inductance and a resistance with the appropriate configuration is connected, the resulting force reflected back into the mechanical domain is equivalent to that achieved by a mechanical inerter-based device. The proposed configuration is easy to implement and very versatile, provided a high quality conversion system with negligible losses. With the use of electromagnetic devices, a new generation of vibration absorbers can be realized, for example in the electrical domain it would be relatively uncomplicated to synthesize multi-frequency or real time tunable vibration absorbers by adding electrical components in parallel. In addition by using resistance emulators in the electrical circuits, part of the absorbed vibration energy can be converted into usable power. Here an electromagnetic tuned inerter damper (E-TID) is tested experimentally using real time dynamic substructuring. A voltage compensation unit was developed in order to compensate for coil losses. This voltage compensation unit requires power, which is acquired through harvesting from the vibration energy using a resistance emulator. A power balance analysis was developed in order to ensure the device can be self sufficient. Promising experimental results, using this approach, have been obtained and are presented in this paper. The ultimate goal of this research is the development of autonomous electromagnetic vibration absorbers, able to harvest energy, convert it into usable power, and use it for vibration control and health monitoring.

  7. Testing New Inert Matrix and Thoria Fuels for Plutonium Incineration

    SciTech Connect

    Vettraino, F.; Padovan, E.; Tverberg, T.

    2002-07-01

    One major issue for nuclear power continues to be the public concern about rad-waste and proliferation risk induced by large plutonium stockpiles accumulated worldwide. In this context, nuclear fuels which exhibit no-plutonium production, and possibly allow for an efficient utilization of the plutonium to get rid of, are of great interest. This is the basic reason for the efforts that many international institutions are devoting to R and D on such new U-free fuel concepts as Inert Matrix (IMF) and Thorium fuels. At the moment the major merit of such innovative fuels is primarily related to the safe closure of the nuclear fuel cycle as especially expected from those new concepts like ADS (Accelerated Driven System) for the transmutation of plutonium, minor actinides and LLFP. Both ceramic inert matrix (IM) and thoria (T) fuels have been identified as suitable to the scope of burning weapon and civilian plutonium and to act also as possible carrier for transmutation of minor actinides. For testing the irradiation behaviour of these new materials, three kinds of fuels have been selected: inert matrix (IM) fuel, inert matrix thoria-doped (IMT) fuel, and thoria (T) fuel. A first experiment, IFA-652, 40 MWD/kg burnup target, including high enriched uranium (HEU) as fissile phase, instead of plutonium, is currently underway in the Halden HWBR. The reason for this choice was that manufacturing of Pu containing fuels is more complex and there was no fabrication facility available at the needed time for the Pu fuel. It is expected, however, that the relative behaviour of the different kind of matrices would be only slightly dependent on the adopted fissile material. So, the comparison of the in-pile performance of the three fuels will constitute a significant common database also for plutonium bearing fuels. The primary aim for the IFA-652 experiment is the measurement of basic characteristics under LWR irradiation conditions over a period of 4-5 years. The design of a second experiment, truly based on plutonium bearing fuel with 80 MWd/kg target burnup, is under preparation. Beyond exploitation in the future transmuters (ADS), the selected fuels are also considered promising candidates for a more effective burning of all kind of plutonium in the present commercial LWRs, what may represent their near term application especially for the weapon Pu stockpile reduction. Most likely this latter aspect is of interest for a wider number of countries which do exploit the benefits of nuclear energy. (authors)

  8. Inert Anode Life in Low Temperature Reduction Process

    SciTech Connect

    Bradford, Donald R.

    2005-06-30

    The production of aluminum metal by low temperature electrolysis utilizing metal non-consumable anodes and ceramic cathodes was extensively investigated. Tests were performed with traditional sodium fluoride--aluminum fluoride composition electrolytes, potassium fluoride-- aluminum fluoride electrolytes, and potassium fluoride--sodium fluoride--aluminum fluoride electrolytes. All of the Essential First-Tier Requirements of the joint DOE-Aluminum Industry Inert Anode Road Map were achieved and those items yet to be resolved for commercialization of this technology were identified. Methods for the fabrication and welding of metal alloy anodes were developed and tested. The potential savings of energy and energy costs were determined and potential environmental benefits verified.

  9. Polyvinyl alcohol battery separator containing inert filler. [alkaline batteries

    NASA Technical Reports Server (NTRS)

    Sheibley, D. W.; Hsu, L. C.; Manzo, M. A. (inventors)

    1981-01-01

    A cross-linked polyvinyl alcohol battery separator is disclosed. A particulate filler, inert to alkaline electrolyte of an alkaline battery, is incorporated in the separator in an amount of 1-20% by weight, based on the weight of the polyvinyl alcohol, and is dispersed throughout the product. Incorporation of the filler enhances performance and increases cycle life of alkaline batteries when compared with batteries containing a similar separator not containing filler. Suitable fillers include titanates, silicates, zirconates, aluminates, wood floor, lignin, and titania. Particle size is not greater than about 50 microns.

  10. Inert scalar dark matter in an extra dimension inspired model

    SciTech Connect

    Lineros, R.A.; Santos, F.A. Pereira dos E-mail: fabio.alex@fis.puc-rio.br

    2014-10-01

    In this paper we analyze a dark matter model inspired by theories with extra dimensions. The dark matter candidate corresponds to the first Kaluza–Klein mode of an real scalar added to the Standard Model. The tower of new particles enriches the calculation of the relic abundance. For large mass splitting, the model converges to the predictions of the inert singlet dark matter model. For nearly degenerate mass spectrum, coannihilations increase the cross-sections used for direct and indirect dark matter searches. Moreover, the Kaluza–Klein zero mode can mix with the SM higgs and further constraints can be applied.

  11. Separation of Nuclear Fuel Surrogates from Silicon Carbide Inert Matrix

    SciTech Connect

    Dr. Ronald Baney

    2008-12-15

    The objective of this project has been to identify a process for separating transuranic species from silicon carbide (SiC). Silicon carbide has become one of the prime candidates for the matrix in inert matrix fuels, (IMF) being designed to reduce plutonium inventories and the long half-lives actinides through transmutation since complete reaction is not practical it become necessary to separate the non-transmuted materials from the silicon carbide matrix for ultimate reprocessing. This work reports a method for that required process.l

  12. Constraints to Dark Matter from Inert Higgs Doublet Model

    E-print Network

    Díaz, Marco Aurelio; Urrutia-Quiroga, Sebastián

    2015-01-01

    We study the Inert Higgs Doublet Model and its CP-even Higgs $H$ as the only source for dark matter. It is found that three mass regions of the CP-even Higgs can give the correct dark matter relic density. The low mass region (between 3 and 50 GeV) is ruled out. New direct dark matter detection experiments will probe the intermediate (between 60 and 100 GeV) and high (heavier than 550 GeV) mass regions. Collider experiments are advised to search for $D^\\pm \\to HW^\\pm$ decay in the two jets plus missing energy channel.

  13. investigation of ISI excimer pulse shaping for inert confined fusion

    NASA Astrophysics Data System (ADS)

    Gao, Zhixing; Lu, Ze; Zhang, Haifeng; Xiang, Yihuai; Hu, Fengming; Li, Jing; Tang, Xiuzhang

    2013-05-01

    The effort of ISI excimer pulse shaping based on gain depletion for inert confined fusion (ICF) in Heaven-I KrF laser system was introduced. The 24ns ISI pulse has been self-shortened to 10ns with a unique set-up call pulse feedback based on gain switch, which can be combined with the EFISI for the high uniformity beam profile. The shorter ISI pulses with the duration of 3~10ns have been obtained with laser quenching. The further proposal to generate a complex pulse shape for ICF based on gain depletion was discussed in this paper.

  14. A Microgravity Helium Dilution Cooler

    NASA Technical Reports Server (NTRS)

    Roach, Pat R.; Sperans, Joel (Technical Monitor)

    1994-01-01

    We are developing a He-3-He-4 dilution cooler to operate in microgravity. It uses charcoal adsorption pumps and heaters for its operation; it has no moving parts. It currently operates cyclically to well below 0.1 K and we have designed a version to operate continuously. We expect that the continuous version will be able to provide the long-duration cooling that many experiments need at temperatures down to 0.040 K. More importantly, such a dilution cooler could provide the precooling that enables the use of adiabatic demagnetization techniques that can reach temperatures below 0.001 K. At temperatures below 0.002 K many fascinating microgravity experiments on superfluid He-3 become possible. Among the possibilities are: research into a superfluid He-3 gyroscope, study of the nucleation of the B-phase of superfluid He-3 when the sample is floating out of contact with walls, study of the anisotropy of the surface tension of the B-phase, and NMR experiments on tiny free-floating clusters of superfluid He-3 atoms that should model the shell structure of nuclei.

  15. Flow characterization and dilution effects of N2 and CO2 on premixed CH4/air flames in a swirl-stabilized combustor

    NASA Astrophysics Data System (ADS)

    Han, Yue; Cai, Guo-Biao; Wang, Hai-Xing; Renou, Bruno; Boukhalfa, Abdelkrim

    2014-03-01

    Numerically-aided experimental studies are conducted on a swirl-stabilized combustor to investigate the dilution effects on flame stability, flame structure, and pollutant emissions of premixed CH4/air flames. Our goal is to provide a systematic assessment on combustion characteristics in diluted regimes for its application to environmentally-friendly approaches such as biogas combustion and exhaust-gas recirculation technology. Two main diluting species, N2 and CO2, are tested at various dilution rates. The results obtained by means of optical diagnostics show that five main flame regimes can be observed for N2-diluted flames by changing excess air and dilution rate. CO2-diluted flames follow the same pattern evolution except that all the domains are shifted to lower excess air. Both N2 and CO2 dilution affect the lean blowout (LBO) limits negatively. This behavior can be counter-balanced by reactant preheating which is able to broaden the flammability domain of the diluted flames. Flame reactivity is degraded by increasing dilution rate. Meanwhile, flames are thickened in the presence of both diluting species. NOx emissions are significantly reduced with dilution and proved to be relevant to flame stability diagrams: slight augmentation in NOx emission profiles is related to transitional flame states where instability occurs. Although dilution results in increase in CO emissions at certain levels, optimal dilution rates can still be proposed to achieve an ideal compromise.

  16. Dilution Robustness for Mean Field Ferromagnets

    E-print Network

    Adriano Barra; Federico Camboni; Pierluigi Contucci

    2009-03-26

    In this work we compare two different random dilution of a mean field ferromagnet: the first model is built on a Bernoulli-diluted network while the second lives on a Poisson-diluted network. While it is known that the two models have in the thermodynamic limit the same free energy we investigate on the structural constraints that the two models must fulfill. We rigorously derive for each model the set of identities for the multi-overlaps distribution using different methods for the two dilutions: constraints in the former model are obtained by studying the consequences of the self-averaging of the internal energy density, while in the latter are obtained by a stochastic-stability technique. Finally we prove that the identities emerging in the two models are the same, showing "robustness" of the ferromagnetic properties of diluted networks with respect to the details of dilution.

  17. Probing the Inert Doublet Dark Matter Model with Cherenkov Telescopes

    E-print Network

    Camilo Garcia-Cely; Michael Gustafsson; Alejandro Ibarra

    2015-12-09

    We present a detailed study of the annihilation signals of the inert dark matter doublet model in its high mass regime. Concretely, we study the prospects to observe gamma-ray signals of the model in current and projected Cherenkov telescopes taking into account the Sommerfeld effect and including the contribution to the spectrum from gamma-ray lines as well as from internal bremsstrahlung. We show that present observations of the galactic center by the H.E.S.S. instrument are able exclude regions of the parameter space that give the correct dark matter relic abundance. In particular, models with the charged and the neutral components of the inert doublet nearly degenerate in mass have strong gamma-ray signals. Furthermore, for dark matter particle masses above 1 TeV, we find that the non-observation of the continuum of photons generated by the hadronization of the annihilation products typically give stronger constraints on the model parameters than the sharp spectral features associated to annihilation into monochromatic photons and the internal bremsstrahlung process. Lastly, we also analyze the interplay between indirect and direct detection searches for this model, concluding that the prospects for the former are more promising. In particular, we find that the upcoming Cherenkov Telescope Array will be able to probe a significant part of the high mass regime of the model.

  18. Dilute Oxygen Combustion Phase 2 Final Report

    SciTech Connect

    Ryan, H.M.; Riley, M.F.; Kobayashi, H.

    2005-09-30

    A novel burner, in which fuel (natural gas) and oxidant (oxygen or air) are separately injected into a furnace, shows promise for achieving very low nitrogen oxide(s) (NOx) emissions for commercial furnace applications. The dilute oxygen combustion (DOC) burner achieves very low NOx through in-furnace dilution of the oxidant stream prior to combustion, resulting in low flame temperatures, thus inhibiting thermal NOx production. The results of a fundamental and applied research effort on the development of the DOC burner are presented. In addition, the results of a market survey detailing the potential commercial impact of the DOC system are disclosed. The fundamental aspects of the burner development project involved examining the flame characteristics of a natural gas turbulent jet in a high-temperature (~1366 K) oxidant (7-27% O2 vol. wet). Specifically, the mass entrainment rate, the flame lift-off height, the velocity field and major species field of the jet were evaluated as a function of surrounding-gas temperature and composition. The measured entrainment rate of the fuel jet decreased with increasing oxygen content in the surrounding high-temperature oxidant, and was well represented by the d+ scaling correlation found in the literature. The measured flame lift-off height decreased with increasing oxygen content and increasing temperature of the surrounding gas. An increase in surrounding-gas oxygen content and/or temperature inhibited the velocity decay within the jet periphery as a function of axial distance as compared to isothermal turbulent jets. However, the velocity measurements were only broadly represented by the d+ scaling correlation. Several DOC burner configurations were tested in a laboratory-scale furnace at a nominal firing rate of 185 kW (~0.63 MMBtu/h). The flue gas composition was recorded as a function of furnace nitrogen content, furnace temperature, burner geometric arrangement, firing rate, and fuel injection velocity. NOx emissions increased with increasing furnace nitrogen content and furnace temperature, but remained relatively insensitive to variations in fuel injection velocity and firing rate. NOx emissions below 5-10-3 g/MJ (10 ppm-air equivalent at 3% O2 dry) were obtained for furnace temperatures below 1533 K (2300?F) and furnace nitrogen levels between 1 and 40%. CO emissions were typically low (<35 ppm). Detailed in-furnace species measurements revealed the importance of the interior furnace circulation patterns, as influenced by fuel and oxidant injection schemes, on pollutant emissions. The combustion stability traits of several DOC burner arrangements were ascertained through furnace pressure measurements, wit6h increased stability occurring as furnace temperature increased and as the separation distance between fuel and oxidant inputs decreased. Based on current market conditions, oxy-fuel conversion of batch steel reheat furnaces with a DOC burner is justified on the basis of lower utility costs alone. However, conversion of continuous steel reheat furnaces, which are responsible for most steel production, required additional economic incentives, such as further fuel savings, increased furnace productivity, or emission credits.

  19. Dilute Oxygen Combustion Phase I Final Report

    SciTech Connect

    Ryan, H.M.; Riley, M.F.; Kobayashi, H.

    1997-10-31

    A novel burner, in which fuel (natural gas) and oxidant (oxygen or air) are separately injected into a furnace, shows promise for achieving very low nitrogen oxide(s) (NOx) emissions for commercial furnace applications. The dilute oxygen combustion (DOC) burner achieves very low NOx through in-furnace dilution of the oxidant stream prior to combustion, resulting in low flame temperatures, thus inhibiting thermal NOx production. The results of a fundamental and applied research effort on the development of the DOC burner are presented. In addition, the results of a market survey detailing the potential commercial impact of the DOC system are disclosed. The fundamental aspects of the burner development project involved examining the flame characteristics of a natural gas turbulent jet in a high-temperature (~1366 K) oxidant (7-27% O2 vol. wet). Specifically, the mass entrainment rate, the flame lift-off height, the velocity field and major species field of the jet were evaluated as a function of surrounding-gas temperature and composition. The measured entrainment rate of the fuel jet decreased with increasing oxygen content in the surrounding high-temperature oxidant, and was well represented by the d+ scaling correlation found in the literature. The measured flame lift-off height decreased with increasing oxygen content and increasing temperature of the surrounding gas. An increase in surrounding-gas oxygen content and/or temperature inhibited the velocity decay within the jet periphery as a function of axial distance as compared to isothermal turbulent jets. However, the velocity measurements were only broadly represented by the d+ scaling correlation. Several DOC burner configurations were tested in a laboratory-scale furnace at a nominal firing rate of 185 kW (~0.63 MMBtu/h). The flue gas composition was recorded as a function of furnace nitrogen content, furnace temperature, burner geometric arrangement, firing rate, and fuel injection velocity. NOx emissions increased with increasing furnace nitrogen content and furnace temperature, but remained relatively insensitive to variations in fuel injection velocity and firing rate. NOx emissions below 5-10-3 g/MJ (10 ppm-air equivalent at 3% O2 dry) were obtained for furnace temperatures below 1533 K (2300°F) and furnace nitrogen levels between 1 and 40%. CO emissions were typically low (<35 ppm). Detailed in-furnace species measurements revealed the importance of the interior furnace circulation patterns, as influenced by fuel and oxidant injection schemes, on pollutant emissions. The combustion stability traits of several DOC burner arrangements were ascertained through furnace pressure measurements, wit6h increased stability occurring as furnace temperature increased and as the separation distance between fuel and oxidant inputs decreased. Based on current market conditions, oxy-fuel conversion of batch steel reheat furnaces with a DOC burner is justified on the basis of lower utility costs alone. However, conversion of continuous steel reheat furnaces, which are responsible for most steel production, required additional economic incentives, such as further fuel savings, increased furnace productivity, or emission credits.

  20. Dilute oxygen combustion. Phase I report

    SciTech Connect

    1997-10-01

    A novel burner, in which fuel (natural gas) and oxidant (oxygen or air) are separately injected into a furnace, shows promise for achieving very low nitrogen oxide(s) (NO{sub x}) emissions for commercial furnace applications. The dilute oxygen combustion (DOC) burner achieves very low NO{sub x} through in-furnace dilution of the oxidant stream prior to combustion, resulting in low flame temperatures, thus inhibiting thermal NO{sub x} production. The results of a fundamental and applied research effort on the development of the DOC burner are presented. In addition, the results of a market survey detailing the potential commercial impact of the DOC system are disclosed. The fundamental aspects of the burner development project involved examining the flame characteristics of a natural gas turbulent jet in a high-temperature ({approximately}1366 K) oxidant (7-27% O{sub 2} vol. wet). Specifically, the mass entrainment rate, the flame lift-off height, the velocity field and major species field of the jet were evaluated as a function of surrounding-gas temperature and composition. The measured entrainment rate of the fuel jet decreased with increasing oxygen content in the surrounding high-temperature oxidant, and was well represented by the d{sup +} scaling correlation found in the literature. The measured flame lift-off height decreased with increasing oxygen content and increasing temperature of the surrounding gas. An increase in surrounding-gas oxygen content and/or temperature inhibited the velocity decay within the jet periphery as a function of axial distance as compared to isothermal turbulent jets. However, the velocity measurements were only broadly represented by the d{sup +} scaling correlation. Several DOC burner configurations were tested in a laboratory-scale furnace at a nominal firing rate of 185 kW ({approximately}0.63 MMBtu/h). The flue gas composition was recorded as a function of furnace nitrogen content, furnace temperature, burner geometric arrangement, firing rate, and fuel injection velocity. NO{sub x} emissions increased with increasing furnace nitrogen content and furnace temperature, but remained relatively insensitive to variations in fuel injection velocity and firing rate. NO{sub x} emissions below 5{times}10{sup -3} g/MJ (10 ppm-air equivalent at 3% O{sub 2} dry) were obtained for furnace temperatures below 1533 K (2300{degree}F) and furnace nitrogen levels between 1 and 40%. CO emissions were typically low (<35 ppm). Detailed in- furnace species measurements revealed the importance of the interior furnace circulation patterns, as influenced by fuel and oxidant injection schemes, on pollutant emissions. The combustion stability traits of several DOC burner arrangements were ascertained through furnace pressure measurements, with increased stability occurring as furnace temperature increased and as the separation distance between fuel and oxidant inputs decreased. Based on current market conditions, oxy-fuel conversion of batch steel reheat furnaces with a DOC burner is justified on the basis of utility costs alone. However, conversion of continuous steel reheat furnaces, which are responsible for most steel production, requires additional economic incentives, such as further fuel savings, increased furnace productivity, or emission credits.

  1. XAFS in dilute magnetic semiconductors.

    PubMed

    Sun, Zhihu; Yan, Wensheng; Yao, Tao; Liu, Qinghua; Xie, Yi; Wei, Shiqiang

    2013-10-14

    X-Ray absorption fine structure (XAFS) spectroscopy has experienced a rapid development in the last four decades and has proved to be a powerful structure characterization technique in the study of local environments in condensed matter. In this article, we first introduce the XAFS basic principles including theory, data analysis and experiment in some detail. Then we attempt to make a review on the applications of XAFS to the study of atomic and electronic structure in dilute magnetic semiconductor (DMS) systems. The power of XAFS in characterizing this interesting material system, such as determining the occupation sites and distribution of the dopants, detecting the presence of metal clusters or secondary phases, as well as identifying the defect types and dopant valence, will be illuminated by selected examples. This review should be of interest both to newcomers in the DMS field and to an interdisciplinary community of researchers working in synthesis, characterization and utilization of DMS materials. PMID:23884341

  2. Band anticrossing in dilute nitrides

    SciTech Connect

    Shan, W.; Yu, K.M.; Walukiewicz, W.; Wu, J.; Ager III, J.W.; Haller, E.E.

    2003-12-23

    Alloying III-V compounds with small amounts of nitrogen leads to dramatic reduction of the fundamental band-gap energy in the resulting dilute nitride alloys. The effect originates from an anti-crossing interaction between the extended conduction-band states and localized N states. The interaction splits the conduction band into two nonparabolic subbands. The downward shift of the lower conduction subband edge is responsible for the N-induced reduction of the fundamental band-gap energy. The changes in the conduction band structure result in significant increase in electron effective mass and decrease in the electron mobility, and lead to a large enhance of the maximum doping level in GaInNAs doped with group VI donors. In addition, a striking asymmetry in the electrical activation of group IV and group VI donors can be attributed to mutual passivation process through formation of the nearest neighbor group-IV donor nitrogen pairs.

  3. Dynamics and Structure of Dusty Reacting Flows: Inert Particles in Strained, Laminar, Premixed Flames

    NASA Technical Reports Server (NTRS)

    Egolfopoulos, Fokion N.; Campbell, Charles S.

    1999-01-01

    A detailed numerical study was conducted on the dynamics and thermal response of inert, spherical particles in strained, laminar, premixed hydrogen/air flames. The modeling included the solution of the steady conservation equations for both the gas and particle phases along and around the stagnation streamline of an opposed-jet configuration, and the use of detailed descriptions of chemical kinetics and molecular transport, For the gas phase, the equations of mass, momentum, energy, and species are considered, while for the particle phase, the model is based on conservation equations of the particle momentum balance in the axial and radial direction, the particle number density, and the particle thermal energy equation. The particle momentum equation includes the forces as induced by drag, thermophoresis, and gravity. The particle thermal energy equation includes the convective/conductive heat exchange between the two phases, as well as radiation emission and absorption by the particle. A one-point continuation method is also included in the code that allows for the description of turning points, typical of ignition and extinction behavior. As expected, results showed that the particle velocity can be substantially different than the gas phase velocity, especially in the presence of large temperature gradients and large strain rates. Large particles were also found to cross the gas stagnation plane, stagnate, and eventually reverse as a result of the opposing gas phase velocity. It was also shown that the particle number density varies substantially throughout the flowfield, as a result of the straining of the flow and the thermal expansion. Finally, for increased values of the particle number density, substantial flame cooling to extinction states and modification of the gas phase fluid mechanics were observed. As also expected, the effect of gravity was shown to be important for low convective velocities and heavy particles. Under such conditions, simulations indicate that the magnitude and direction of the gravitational force can substantially affect the profiles of the particle velocity, number density, mass flux, and temperature.

  4. Dynamics and Structure of Dusty Reacting Flows: Inert Particles in Strained, Laminar, Premixed Flames

    NASA Technical Reports Server (NTRS)

    Egolfopoulos, Fokion N.; Campbell, Charles S.; Wu, Ming-Shin (Technical Monitor)

    1999-01-01

    A detailed numerical study was conducted on the dynamics and thermal response of inert spherical particles in strained, laminar, premixed hydrogen/air flames. The modeling included the solution of the steady conservation equations for both the gas and particle phases along and around the stagnation streamline of an opposed-jet configuration, and the use of detailed descriptions of chemical kinetics and molecular transport. For the gas phase, the equations of mass, momentum, energy, and species are considered, while for the particle phase, the model is based on conservation equations of the particle momentum balance in the axial and radial direction, the particle number density, and the particle thermal energy equation. The particle momentum equation includes the forces as induced by drag, thermophoresis, and gravity. The particle thermal energy equation includes the convective/conductive heat exchange between the two phases, as well as radiation emission and absorption by the particle. A one-point continuation method is also included in the code that allows for the description of turning points, typical of ignition and extinction behavior. As expected, results showed that the particle velocity can be substantially different than the gas phase velocity, especially in the presence of large temperature gradients and large strain rates. Large particles were also found to cross the gas stagnation plane, stagnate, and eventually reverse as a result of the opposing gas phase velocity. It was also shown that the particle number density varies substantially throughout the flowfield, as a result of the straining of the flow and the thermal expansion. Finally, for increased values of the particle number density, substantial flame cooling to extinction states and modification of the gas phase fluid mechanics were observed. As also expected, the effect of gravity was shown to be important for low convective velocities and heavy particles. Under such conditions, simulations indicate that the magnitude and direction of the gravitational force can substantially affect the profiles of the particle velocity, number density, mass flux, and temperature.

  5. Cold Inertance Tube for 4 K Stirling Type Pulse Tube Cryocoolers

    NASA Astrophysics Data System (ADS)

    Li, ZhuoPei; Gan, ZhiHua; Qiu, LiMin

    The losses in the regenerator are minimized when the amplitude of the mass flow is minimized for a given acoustic power which requires that the mass flow lags the pressure by about 30° at the cold end of regenerator. The phase shift provided by an inertance tube is strongly influenced by the temperature of the inertance tube and the acoustic power at the cold end of the regenerator. For a 4 K Stirling type pulse tube cryocooler, the acoustic power at the cold end of the regenerator decreases significantly with the temperature thereby it's difficult to achieve ideal phase relationship with ambient inertance tube. While cold inertance tube provide a larger phase shift in that the viscosity of the working fluid decreases and the density increases as the temperature decreases. However, use of cold inertance tube increases additional heat load to the regenerator. Therefore it's of great significance to determine when a cold inertance tube should be used. In this paper effect of temperature of inertance tube is calculated for a 4 K Stirling type pulse tube cryocooler with different acoustic powers at the cold end. A comparison of ambient temperature inertance tube and cold inertance tube is made.

  6. Unidentified Inert Ingredients in Pesticides: Implications for Human and Environmental Health

    PubMed Central

    Cox, Caroline; Surgan, Michael

    2006-01-01

    Background By statute or regulation in the United States and elsewhere, pesticide ingredients are divided into two categories: active and inert (sometimes referred to as other ingredients, adjuvants, or coformulants). Despite their name, inert ingredients may be biologically or chemically active and are labeled inert only because of their function in the formulated product. Most of the tests required to register a pesticide are performed with the active ingredient alone, not the full pesticide formulation. Inert ingredients are generally not identified on product labels and are often claimed to be confidential business information. Objectives In this commentary, we describe the shortcomings of the current procedures for assessing the hazards of pesticide formulations and demonstrate that inert ingredients can increase the toxicity of and potential exposure to pesticide formulations. Discussion Inert ingredients can increase the ability of pesticide formulations to affect significant toxicologic end points, including developmental neurotoxicity, genotoxicity, and disruption of hormone function. They can also increase exposure by increasing dermal absorption, decreasing the efficacy of protective clothing, and increasing environmental mobility and persistence. Inert ingredients can increase the phytotoxicity of pesticide formulations as well as the toxicity to fish, amphibians, and microorganisms. Conclusions Pesticide registration should require full assessment of formulations. Evaluations of pesticides under the National Environmental Policy Act, the Endangered Species Act, and similar statutes should include impact assessment of formulations. Environmental monitoring for pesticides should include inert ingredients. To enable independent research and risk assessment, inert ingredients should be identified on product labels. PMID:17185266

  7. Fiber optic oxygen sensor using fluorescence quenching for aircraft inerting fuel tank applications

    NASA Astrophysics Data System (ADS)

    Panahi, Allen

    2009-05-01

    On July 18, 2008, the FAA mandated that new aircraft are to include inerting technology to significantly reduce the potential for flammable vapor spaces in center wing fuel tanks. All passenger aircraft constructed since 1991 must also be retrofitted with this technology. This ruling is the result of 18 aircraft that have experienced fuel tank flammable vapor ignition incidents since 1960. Included in these are the TWA 800 and Avianca Flight 203 incidents that resulted in 337 total fatalities. Comprised of heavier hydrocarbon components, jet fuel is much less volatile, with Jet A having a flash point of approximately 100°F and JP-4 having a flash point of approximately 0°F. In contrast, straight-run gasoline has a flash point of approximately -40°F. The flash point is the minimum temperature where a liquid fuel can generate enough vapor to form a flammable mixture with air. If the temperature is below the flash point there isn't enough fuel evaporating to form a flammable fuel-air mixture. Since jet fuel and gasoline have similar flammable concentration limits, gasoline must produce much more vapor at a given temperature to have such a low flash point; hence gasoline is much more volatile than jet fuel. In this paper we explore Fluorescence Technology as applied to the design and development of O2 sensors that can be used for this application and discuss the various test and measurement techniques used to estimate the O2 gas concentration. We compare the various intensity based approaches and contrast them with the frequency domain techniques that measure phase to extract fluorescent lifetimes. The various inerting fuel tank requirements are explained and finally a novel compact measurement system using that uses the frequency heterodyning cross correlation technique that can be used for various applications is described in detail while the benefits are explored together with some test data collected.

  8. Dilute Surfactant Methods for Carbonate Formations

    SciTech Connect

    Kishore K. Mohanty

    2006-02-01

    There are many fractured carbonate reservoirs in US (and the world) with light oil. Waterflooding is effective in fractured reservoirs, if the formation is water-wet. Many fractured carbonate reservoirs, however, are mixed-wet and recoveries with conventional methods are low (less than 10%). The process of using dilute anionic surfactants in alkaline solutions has been investigated in this work for oil recovery from fractured oil-wet carbonate reservoirs both experimentally and numerically. This process is a surfactant-aided gravity drainage where surfactant diffuses into the matrix, lowers IFT and contact angle, which decrease capillary pressure and increase oil relative permeability enabling gravity to drain the oil up. Anionic surfactants have been identified which at dilute concentration of 0.05 wt% and optimal salinity can lower the interfacial tension and change the wettability of the calcite surface to intermediate/water-wet condition as well or better than the cationic surfactant DTAB with a West Texas crude oil. The force of adhesion in AFM of oil-wet regions changes after anionic surfactant treatment to values similar to those of water-wet regions. The AFM topography images showed that the oil-wetting material was removed from the surface by the anionic surfactant treatment. Adsorption studies indicate that the extent of adsorption for anionic surfactants on calcite minerals decreases with increase in pH and with decrease in salinity. Surfactant adsorption can be minimized in the presence of Na{sub 2}CO{sub 3}. Laboratory-scale surfactant brine imbibition experiments give high oil recovery (20-42% OOIP in 50 days; up to 60% in 200 days) for initially oil-wet cores through wettability alteration and IFT reduction. Small (<10%) initial gas saturation does not affect significantly the rate of oil recovery in the imbibition process, but larger gas saturation decreases the oil recovery rate. As the core permeability decreases, the rate of oil recovery reduces, and this reduction can be scaled by the gravitational dimensionless time. Mechanistic simulation of core-scale surfactant brine imbibition matches the experimentally observed imbibition data. In-situ distributions observed through simulation indicate that surfactant diffusion (which depends on temperature and molecular weight) is the rate limiting step. Most of the oil is recovered through gravitational forces. Oil left behind at the end of this process is at its residual oil saturation. The capillary and Bond numbers are not large enough to affect the residual oil saturation. At the field-scale, 50% of the recoverable oil is produced in about 3 years if the fracture spacing is 1 m and 25% if 10 m, in the example simulated. Decreasing fracture spacing and height, increasing permeability, and increasing the extent of wettability alteration increase the rate of oil recovery from surfactant-aided gravity drainage. This dilute surfactant aided gravity-drainage process is relatively cheap. The chemical cost for a barrel of oil produced is expected to be less than $1.

  9. Electrocoalescence based serial dilution of microfluidic droplets

    PubMed Central

    Bhattacharjee, Biddut; Vanapalli, Siva A.

    2014-01-01

    Dilution of microfluidic droplets where the concentration of a reagent is incrementally varied is a key operation in drop-based biological analysis. Here, we present an electrocoalescence based dilution scheme for droplets based on merging between moving and parked drops. We study the effects of fluidic and electrical parameters on the dilution process. Highly consistent coalescence and fine resolution in dilution factor are achieved with an AC signal as low as 10?V even though the electrodes are separated from the fluidic channel by insulator. We find that the amount of material exchange between the droplets per coalescence event is high for low capillary number. We also observe different types of coalescence depending on the flow and electrical parameters and discuss their influence on the rate of dilution. Overall, we find the key parameter governing the rate of dilution is the duration of coalescence between the moving and parked drop. The proposed design is simple incorporating the channel electrodes in the same layer as that of the fluidic channels. Our approach allows on-demand and controlled dilution of droplets and is simple enough to be useful for assays that require serial dilutions. The approach can also be useful for applications where there is a need to replace or wash fluid from stored drops. PMID:25379096

  10. Evolution of Universe to the present inert phase

    E-print Network

    I. F. Ginzburg; K. A. Kanishev; M. Krawczyk; D. Sokolowska

    2010-09-23

    We assume that current state of the Universe can be described by the Inert Doublet Model, containing two scalar doublets, one of which is responsible for EWSB and masses of particles and the second one having no couplings to fermions and being responsible for dark matter. We consider possible evolutions of the Universe to this state during cooling down of the Universe after inflation. We found that in the past Universe could pass through phase states having no DM candidate. In the evolution via such states in addition to a possible EWSB phase transition (2-nd order) the Universe sustained one 1-st order phase transition or two phase transitions of the 2-nd order.

  11. Advances in the study of striations in inert gases

    NASA Astrophysics Data System (ADS)

    Golubovskii, Yu. B.; Nekuchaev, V. O.; Skoblo, A. Yu.

    2014-12-01

    We present a review of studies of striations in a dc discharge in inert gases over recent decades. Physical mechanisms of stratification are described for various discharge conditions. Main attention is paid to striations at low pressures and small currents ( S, P, and R striations). The origin of these striations is associated with electron bunching in spatially periodic resonant fields. The idea of this mechanism and qualitative interpretation of the S and P striations based on the analytic theory are described in the pioneering work by L.D. Tsendin (1982). We describe the evolution of these ideas on quantitative level. New ideas concerning nonintegral resonances responsible for the formation of R striations are considered. The theory is compared with experiment.

  12. DILUTE SURFACTANT METHODS FOR CARBONATE FORMATIONS

    SciTech Connect

    Kishore K. Mohanty

    2005-07-01

    There are many carbonate reservoirs in US (and the world) with light oil and fracture pressure below its minimum miscibility pressure (or reservoir may be naturally fractured). Many carbonate reservoirs are naturally fractured. Waterflooding is effective in fractured reservoirs, if the formation is water-wet. Many fractured carbonate reservoirs, however, are mixed-wet and recoveries with conventional methods are low (less than 10%). Thermal and miscible tertiary recovery techniques are not effective in these reservoirs. Surfactant flooding (or huff-n-puff) is the only hope, yet it was developed for sandstone reservoirs in the past. The goal of this research is to evaluate dilute (hence relatively inexpensive) surfactant methods for carbonate formations and identify conditions under which they can be effective. Laboratory imbibition tests show that imbibition rate is not very sensitive to the surfactant concentration (in the range of 0.05-0.2 wt%) and small amounts of trapped gas saturation. It is however very sensitive to oil permeability and water-oil-ratio. Less than 0.5 M Na2CO3 is needed for in situ soap generation and low adsorption; NaCl can be added to reach the necessary total salinity. The simulation result matches the laboratory imbibition experimental data. Small fracture spacing and high permeability would be needed for high rate of recovery.

  13. Dry dilution refrigerator with He-4 precool loop

    SciTech Connect

    Uhlig, Kurt

    2014-01-29

    He-3/He-4 dilution refrigerators (DR) are very common in sub-Kelvin temperature research. We describe a pulse tube precooled DR where a separate He-4 circuit condenses the He-3 of the dilution loop. Whereas in our previous work the dilution circuit and the He-4 circuit were separate, we show how the two circuits can be combined. Originally, the He-4 loop with a base temperature of ? 1 K was installed to make an additional cooling power of up to 100 mW available to cool cold amplifiers and electrical lines. In the new design, the dilution circuit is run through a heat exchanger in the vessel of the He-4 circuit so condensation of the He-3 stream of the DR is done by the He-4 stage. A much reduced condensation time (factor of 2) of the He-3/He-4 gas mixture at the beginning of an experiment is achieved. A compressor is no longer needed with the DR as the condensation pressure remains below atmospheric pressure at all times; thus the risk of losing expensive He-3 gas is small. The performance of the DR has been improved compared to previous work: The base temperature of the mixing chamber at a small He-3 flow rate is now 4.1 mK; at the highest He-3 flow rate of 1.2 mmol/s this temperature increases to 13 mK. Mixing chamber temperatures were measured with a cerium magnesium nitrate (CMN) thermometer which was calibrated with a superconducting fixed point device.

  14. Dry dilution refrigerator with He-4 precool loop

    NASA Astrophysics Data System (ADS)

    Uhlig, Kurt

    2014-01-01

    He-3/He-4 dilution refrigerators (DR) are very common in sub-Kelvin temperature research. We describe a pulse tube precooled DR where a separate He-4 circuit condenses the He-3 of the dilution loop. Whereas in our previous work the dilution circuit and the He-4 circuit were separate, we show how the two circuits can be combined. Originally, the He-4 loop with a base temperature of ˜ 1 K was installed to make an additional cooling power of up to 100 mW available to cool cold amplifiers and electrical lines. In the new design, the dilution circuit is run through a heat exchanger in the vessel of the He-4 circuit so condensation of the He-3 stream of the DR is done by the He-4 stage. A much reduced condensation time (factor of 2) of the He-3/He-4 gas mixture at the beginning of an experiment is achieved. A compressor is no longer needed with the DR as the condensation pressure remains below atmospheric pressure at all times; thus the risk of losing expensive He-3 gas is small. The performance of the DR has been improved compared to previous work: The base temperature of the mixing chamber at a small He-3 flow rate is now 4.1 mK; at the highest He-3 flow rate of 1.2 mmol/s this temperature increases to 13 mK. Mixing chamber temperatures were measured with a cerium magnesium nitrate (CMN) thermometer which was calibrated with a superconducting fixed point device.

  15. Analysis of several hazardous conditions for large transfer and back-dilution sequences in Tank 241-SY-101

    SciTech Connect

    CW Stewart; LA Mahoney; WB Barton

    2000-01-28

    The first transfer of 89 kgal of waste and back-dilution of 61 kgal of water in Hanford Tank 241-SY-101 was accomplished December 18--20, 1999. Limits were placed on the transfer and back-dilution volumes because of concerns about potential gas release, crust sinking, and degradation of mixer pump performance. Additional transfers and back-dilutions are being planned that will bring the total to 500 kgal, which should dissolve a large fraction of the solids in the tank and dilute it well beyond the point where significant gas retention can occur. This report provides the technical bases for removing the limits on transfer and back-dilution volume by evaluating the potential consequences of several postulated hazardous conditions in view of the results of the first campaign and results of additional analyses of waste behavior.

  16. Gas stream purifier

    NASA Technical Reports Server (NTRS)

    Adam, Steven J.

    1994-01-01

    A gas stream purifier has been developed that is capable of removing corrosive acid, base, solvent, organic, inorganic, and water vapors as well as particulates from an inert mixed gas stream using only solid scrubbing agents. This small, lightweight purifier has demonstrated the ability to remove contaminants from an inert gas stream with a greater than 99 percent removal efficiency. The Gas Stream Purifier has outstanding market and sales potential in manufacturing, laboratory and science industries, medical, automotive, or any commercial industry where pollution, contamination, or gas stream purification is a concern. The purifier was developed under NASA contract NAS9-18200 Schedule A for use in the international Space Station. A patent application for the Gas Stream Purifier is currently on file with the United States Patent and Trademark Office.

  17. 75 FR 30300 - Restricting the Mailing of Replica or Inert Explosive Devices

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-01

    ...Restricting the Mailing of Replica or Inert Explosive Devices AGENCY: Postal Service\\TM...restricting the mailing of replica or inert explosive devices, such as simulated grenades...dangerous but bear a realistic appearance to explosive devices, to Registered Mail\\TM\\...

  18. 30 CFR 75.1107-12 - Inerting of mine atmosphere prohibited.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Inerting of mine atmosphere prohibited. 75.1107-12 Section 75.1107-12 Mineral...Underground Equipment § 75.1107-12 Inerting of mine atmosphere prohibited. No fire suppression device designed to...

  19. 30 CFR 75.1107-12 - Inerting of mine atmosphere prohibited.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Inerting of mine atmosphere prohibited. 75.1107-12 Section 75.1107-12 Mineral...Underground Equipment § 75.1107-12 Inerting of mine atmosphere prohibited. No fire suppression device designed to...

  20. 30 CFR 75.1107-12 - Inerting of mine atmosphere prohibited.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Inerting of mine atmosphere prohibited. 75.1107-12 Section 75.1107-12 Mineral...Underground Equipment § 75.1107-12 Inerting of mine atmosphere prohibited. No fire suppression device designed to...

  1. 30 CFR 75.1107-12 - Inerting of mine atmosphere prohibited.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Inerting of mine atmosphere prohibited. 75.1107-12 Section 75.1107-12 Mineral...Underground Equipment § 75.1107-12 Inerting of mine atmosphere prohibited. No fire suppression device designed to...

  2. 75 FR 282 - Restricting the Mailing of Replica or Inert Explosive Devices

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-05

    ... a Federal Register proposed rule (73 FR 12321) on March 7, 2008 to prohibit replica and inert... mailing of replica or inert explosive devices, such as grenades, be sent by Registered Mail TM only. DATES..., containing the name and address of the commenter, may be sent to: MailingStandards@usps.gov , with a...

  3. Mechanisms controlling the global oceanic distribution of the inert gases argon, nitrogen and neon

    E-print Network

    Emerson, Steven R.

    Mechanisms controlling the global oceanic distribution of the inert gases argon, nitrogen and neon formation. We present argon, nitrogen, and neon data from the subtropical and subpolar North Pacific of the inert gases argon, nitrogen and neon, Geophys. Res. Lett., 29(23), 2120, doi:10.1029/2002GL015273, 2002

  4. Development and Comparison of Two Types of Cryogen-Free Dilution Refrigerator

    NASA Astrophysics Data System (ADS)

    Hata, T.; Matsumoto, T.; Obara, K.; Yano, H.; Ishikawa, O.; Handa, A.; Togitani, S.; Nishitani, T.

    2014-04-01

    Dilution refrigerators are an important tool used in solid state and quantum fluid physics for cooling to temperatures below 0.3 K. Conventional dilution refrigerators consume a lot of liquid helium, which has to be recharged in a helium bath every few days. Cryogen-free dilution refrigerators, however, do not use liquid helium and then automatic operation by electricity can be possible from room temperature to the mK region. In near future, therefore, most conventional dilution refrigerators will be replaced by cryogen-free refrigerators because they are easy to operate, do not require maintenance and do not consume helium. We have developed two types of cryogen-free dilution refrigerator. One is directly cooled by a pulse tube refrigerator in the same cryostat using copper thin wires as a thermal link, and the other is cooled by a separate Gifford McMahon refrigerator using circulating helium gas through a flexible syphon tube. The latter has been developed as a vibration-free cryogen-free dilution refrigerator. These two types of cryogen-free dilution refrigerator are compared considering several key points: base temperature, precooling time, minimum temperature and vibration amplitude.

  5. Gas mixtures for spark gap closing switches

    DOEpatents

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

    1987-02-20

    Gas mixtures for use in spark gap closing switches comprised of fluorocarbons and low molecular weight, inert buffer gases. To this can be added a third gas having a low ionization potential relative to the buffer gas. The gas mixtures presented possess properties that optimized the efficiency spark gap closing switches. 6 figs.

  6. One-loop contributions to neutral minima in the inert doublet model

    E-print Network

    Ferreira, P M

    2015-01-01

    The vacuum structure of the inert doublet model is analysed at the one-loop level, to verify the validity of tree-level predictions for the properties of the global minimum. An inert minimum (with massive fermions) and an inert-like minimum (with massless fermions) can coexist at tree level. But the one-loop analysis reveals that the allowed parameter space for the coexistence of more than one minimum is larger than the tree-level expected one. It is also shown that for some choices of parameters, the global minimum found at one-loop may be inert (or inert-like), contrary to what the tree-level analysis points out.

  7. Pulse Tube Coolers with an Inertance Tube: Theory, Modeling and Practice

    NASA Technical Reports Server (NTRS)

    Roach, Pat R.; Kashani, Ali; McCreight, Craig R. (Technical Monitor)

    1997-01-01

    We have studied the advantages to be gained by replacing the conventional orifice of a pulse tube cooler by an inertance tube - a long thin tube that introduces the possibility for additional phase shift between pressure and mass flow in the pulse tube section. The case for the use of an inertance tube is most clearly made with an electrical analogy where the 'inductance' added by the inertance tube allows for optimal power transfer at the cold heat exchanger. Detailed modeling of a pulse tube system with an inertance tube confirms these advantages. Comparison between a laboratory cooler with an orifice and with an inertance tube will be presented and reasons wily it is difficult to realize all the expected gain will be given.

  8. 21 CFR 864.5240 - Automated blood cell diluting apparatus.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 false Automated blood cell diluting apparatus. 864.5240 Section...Devices § 864.5240 Automated blood cell diluting apparatus. (a) Identification. An automated blood cell diluting apparatus is a fully...

  9. 21 CFR 864.5240 - Automated blood cell diluting apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Automated blood cell diluting apparatus. 864.5240 Section...Devices § 864.5240 Automated blood cell diluting apparatus. (a) Identification. An automated blood cell diluting apparatus is a fully...

  10. 21 CFR 864.5240 - Automated blood cell diluting apparatus.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 false Automated blood cell diluting apparatus. 864.5240 Section...Devices § 864.5240 Automated blood cell diluting apparatus. (a) Identification. An automated blood cell diluting apparatus is a fully...

  11. 21 CFR 864.5240 - Automated blood cell diluting apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Automated blood cell diluting apparatus. 864.5240 Section...Devices § 864.5240 Automated blood cell diluting apparatus. (a) Identification. An automated blood cell diluting apparatus is a fully...

  12. 21 CFR 864.5240 - Automated blood cell diluting apparatus.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 false Automated blood cell diluting apparatus. 864.5240 Section...Devices § 864.5240 Automated blood cell diluting apparatus. (a) Identification. An automated blood cell diluting apparatus is a fully...

  13. Development of a constant dilution sampling system for particulate and gaseous pollutant measurements

    NASA Astrophysics Data System (ADS)

    Tzamkiozis, T.; Ntziachristos, L.; Amanatidis, S.; Niemelä, V.; Ukkonen, A.; Samaras, Z.

    2013-08-01

    This paper presents a new concept of a partial flow sampling system (PFSS), involving a two-stage diluter which operates on the principle of underpressure, while exhaust is sampled through a capillary. Due to the low flowrate through the capillary, the diluter may be sampling from a freely exhausting tailpipe and is not prone to pressure variations in the exhaust line. In addition, the PFSS operates at constant pressure conditions even upstream of diesel particle filters that increase the backpressure in the tailpipe. As a result, the PFSS offers a constant dilution ratio (DR) over any engine or vehicle operation condition. This study presents the diluter concept and a straightforward model developed to calculate the DR, depending on the dilution air flowrate and the diluter underpressure. The model is validated using CO2 as a trace gas, and very good agreement is demonstrated between the calculated and the measured DR values. Following validation, the PFSS is combined with aerosol measurement instruments to measure the exhaust particle concentration of a diesel engine operating at different steady-state modes. For demonstrating the stability of the DR and applicability of the PFSS, measurements are conducted with both heavy duty and light duty diesel exhaust gases. Future applications of this device include gas and particle exhaust measurements both in laboratory environments and on-board vehicles.

  14. Effects of External EGR Loop on Cycle-to-Cycle Dynamics of Dilute SI Combustion

    SciTech Connect

    Kaul, Brian C.; Finney, Charles E. A.; Wagner, Robert; Edwards, Michelle L.

    2014-01-01

    Operation of spark-ignition (SI) engines with high levels of charge dilution through exhaust gas recirculation (EGR) achieves significant efficiency gains while maintaining stoichiometric operation for compatibility with three-way catalysts. Dilution levels, however, are limited by cyclic variability including significant numbers of misfires that becomes significant with increasing dilution. This variability has been shown to have both stochastic and deterministic components. Stochastic effects include turbulence, mixing variations, and the like, while the deterministic effect is primarily due to the nonlinear dependence of flame propagation rates and ignition characteristics on the charge composition, which is influenced by the composition of residual gases from prior cycles. The dynamics of operation with an external EGR loop differ substantially from those of dilute operation without external recirculation, both in time-scale and cylinder synchronization effects, especially when misfires are encountered. This paper examines these differences and the implications for prior-cycle-based control strategies.

  15. The influence of dilution gases on multilayer graphene formation in laser pyrolysis

    NASA Astrophysics Data System (ADS)

    Gavrila-Florescu, Lavinia; Sandu, Ion; Dutu, Elena; Morjan, Ion; Birjega, Ruxandra

    2013-08-01

    The work presents the structure and morphology of multilayer graphene formed as components of carbon nanoparticles synthesized by the laser pyrolysis technique. Low aggregated carbon nanoparticles with dimensions between 12 and 33 nm, which present a structured surface with multilayer graphene were synthesized from a C2H2/SF6 gas mixture with different dilution gases. The longest multi-graphene sheets were obtained for a C/F = 3 atomic ratio and when N2O was used as dilution gas. The obtained carbon nanoparticles present electrical conductivity values comparable with those of multi-wall CNTs, but lower than those of single-wall CNTs.

  16. Calibration graphs in isotope dilution mass spectrometry.

    PubMed

    Pagliano, Enea; Mester, Zoltán; Meija, Juris

    2015-10-01

    Isotope-based quantitation is routinely employed in chemical measurements. Whereas most analysts seek for methods with linear theoretical response functions, a unique feature that distinguishes isotope dilution from many other analytical methods is the inherent possibility for a nonlinear theoretical response curve. Most implementations of isotope dilution calibration today either eliminate the nonlinearity by employing internal standards with markedly different molecular weight or they employ empirical polynomial fits. Here we show that the exact curvature of any isotope dilution curve can be obtained from three-parameter rational function, y = f(q) = (a0 + a1q)/(1 + a2q), known as the Padé[1,1] approximant. The use of this function allows eliminating an unnecessary source of error in isotope dilution analysis when faced with nonlinear calibration curves. In addition, fitting with Padé model can be done using linear least squares. PMID:26481988

  17. Helium Dilution Cryocooler for Space Applications

    NASA Technical Reports Server (NTRS)

    Roach, Pat; Hogan, Robert (Technical Monitor)

    2001-01-01

    NASA's New Millenium Program Space Technology presents the Helium Dilution Cryocooler for Space Applications. The topics include: 1) Capability; 2) Applications; and 3) Advantages. This paper is in viewgraph form.

  18. Diluted ferromagnetic semiconductors as spintronic materials

    NASA Astrophysics Data System (ADS)

    Lashkarev, G. V.; Radchenko, M. V.; Karpina, V. A.; Sichkovskyi, V. I.

    2007-02-01

    A brief review of research papers on some diluted magnetic semiconductors is given. Experimental results on the study of the ferromagnetic state in the most promising materials for use in spintronics are presented.

  19. [Influence of dissolved gases on highly diluted aqueous media].

    PubMed

    Belovolova, L V; Glushkov, M V; Vinogradov, E A

    2014-01-01

    In the experiments on redox potential measurement for a series of identical samples of purified and presettled water it was found that the response to ultraviolet irradiation varies appreciably within a few days after treatment, including stepwise changes. In a few hours after exposure, leading to a higher content of reactive oxygen species as compared with the equilibrium values, long-term changes including variations in redox potential and optical system parameters are recorded in water and diluted aqueous media. We propose a heuristic organization model of the water-gas system with an increased content of reactive oxygen species. PMID:25707230

  20. Porous HMX initiation studies -- Sugar as an inert simulant

    SciTech Connect

    Sheffield, S.A.; Gustavsen, R.L.; Alcon, R.R.

    1997-11-01

    For several years the authors have been using magnetic particle velocity gauges to study the shock loading of porous HMX (65 and 73% TMD) of different particle sizes to determine their compaction and initiation characteristics. Because it has been difficult to separate the effects of compaction and reaction, an inert simulant was needed with properties similar to HMX. Sugar was selected as the simulant for several reasons: (1) the particle size distribution of C and H granulated sugar is similar to the coarse HMX the authors have been using (120 {micro}m average size), (2) the particle size of C and H confectioners (powdered) sugar is similar to the fine HMX in the studies (10 {micro}m average size), (3) it is an organic material, and (4) sugar was readily available. Because the densities of HMX and sugar are somewhat different, the authors chose to do the experiments on sugar compacts at 65 and 73% TMD. As expected, no reaction was observed in the sugar experiments. Compaction wave profiles were similar to those measured earlier for the HMX, i.e., the compaction waves in the coarse sugar were quite disperse while those in the fine sugar were much sharper. This indicates that the compaction wave profiles are controlled by particle size and not reaction. Also, the coarse sugar gauge signals exhibited a great deal of noise, thought to the be result of fracto-emission.

  1. Determining inert content in coal dust/rock dust mixture

    DOEpatents

    Sapko, Michael J. (Finleyville, PA); Ward, Jr., Jack A. (Oakmont, PA)

    1989-01-01

    A method and apparatus for determining the inert content of a coal dust and rock dust mixture uses a transparent window pressed against the mixture. An infrared light beam is directed through the window such that a portion of the infrared light beam is reflected from the mixture. The concentration of the reflected light is detected and a signal indicative of the reflected light is generated. A normalized value for the generated signal is determined according to the relationship .phi.=(log i.sub.c `log i.sub.co) / (log i.sub.c100 -log i.sub.co) where i.sub.co =measured signal at 0% rock dust i.sub.c100 =measured signal at 100% rock dust i.sub.c =measured signal of the mixture. This normalized value is then correlated to a predetermined relationship of .phi. to rock dust percentage to determine the rock dust content of the mixture. The rock dust content is displayed where the percentage is between 30 and 100%, and an indication of out-of-range is displayed where the rock dust percent is less than 30%. Preferably, the rock dust percentage (RD%) is calculated from the predetermined relationship RD%=100+30 log .phi.. where the dust mixture initially includes moisture, the dust mixture is dried before measuring by use of 8 to 12 mesh molecular-sieves which are shaken with the dust mixture and subsequently screened from the dust mixture.

  2. Classical scale invariance in the inert doublet model

    E-print Network

    Plascencia, Alexis D

    2015-01-01

    The inert doublet model (IDM) is a minimal extension of the Standard Model (SM) that can account for the dark matter in the universe. Naturalness arguments motivate us to study whether the model can be embedded into a theory with dynamically generated scales. In this work we study a classically scale invariant version of the IDM with a minimal hidden sector, which has a $U(1)_{\\text{CW}}$ gauge symmetry and a complex scalar $\\Phi$. The mass scale is generated in the hidden sector via the Coleman-Weinberg (CW) mechanism and communicated to the two Higgs doublets via portal couplings. Since the CW scalar remains light, acquires a vacuum expectation value and mixes with the SM Higgs boson, the phenomenology of this construction can be modified with respect to the traditional IDM. We analyze the impact of adding this CW scalar and the $Z'$ gauge boson on the calculation of the dark matter relic density and on the spin-independent nucleon cross section for direct detection experiments. Finally, by studying the RG ...

  3. The 3-3-1 model with inert scalar triplet

    E-print Network

    P. V. Dong; T. Phong Nguyen; D. V. Soa

    2013-11-06

    We show that the typical 3-3-1 models are only self-consistent if they contain interactions explicitly violating the lepton number. The 3-3-1 model with right-handed neutrinos can by itself work as an economical 3-3-1 model as a natural recognition of the above criteria while it also results an inert scalar triplet (\\eta) responsible for dark matter. This is ensured by a Z_2 symmetry (assigned so that only \\eta is odd while all other multiplets which perform the economical 3-3-1 model are even), which is not broken by the vacuum. The minimal 3-3-1 model can provide a dark matter by a similar realization. Taking the former into account, we show that the dark matter candidate (H_\\eta) contained in \\eta transforms as a singlet in effective limit under the standard model symmetry and being naturally heavy. The H_\\eta relic density and direct detection cross-section will get right values when the H_\\eta mass is in TeV range as expected. The model predicts the H_\\eta mass m_{H_\\eta}=\\lambda_5\\times 2 TeV and the H_\\eta-nucleon scattering cross-section \\sigma_{H_\\eta-N}=1.56\\times 10^{-44} cm^2, provided that the new neutral Higgs boson is heavy enough than the dark matter.

  4. Investigation of materials for inert electrodes in aluminum electrodeposition cells

    SciTech Connect

    Haggerty, J. S.; Sadoway, D. R.

    1987-09-14

    Work was divided into major efforts. The first was the growth and characterization of specimens; the second was Hall cell performance testing. Cathode and anode materials were the subject of investigation. Preparation of specimens included growth of single crystals and synthesis of ultra high purity powders. Special attention was paid to ferrites as they were considered to be the most promising anode materials. Ferrite anode corrosion rates were studied and the electrical conductivities of a set of copper-manganese ferrites were measured. Float Zone, Pendant Drop Cryolite Experiments were undertaken because unsatisfactory choices of candidate materials were being made on the basis of a flawed set of selection criteria applied to an incomplete and sometimes inaccurate data base. This experiment was then constructed to determine whether the apparatus used for float zone crystal growth could be adapted to make a variety of important based melts and their interactions with candidate inert anode materials. The third major topic was Non Consumable Anode (Data Base, Candidate Compositions), driven by our perception that the basis for prior selection of candidate materials was inadequate. Results are presented. 162 refs., 39 figs., 18 tabs.

  5. Investigation of materials for inert electrodes in aluminum electrodeposition cells

    NASA Astrophysics Data System (ADS)

    Haggerty, J. S.; Sadoway, D. R.

    1987-09-01

    Work was divided into major efforts. The first was the growth and characterization of specimens; the second was Hall cell performance testing. Cathode and anode materials were the subject of investigation. Preparation of specimens included growth of single crystals and synthesis of ultra high purity powders. Special attention was paid to ferrites as they were considered to be the most promising anode materials. Ferrite anode corrosion rates were studied and the electrical conductivities of a set of copper-manganese ferrites were measured. Float Zone, Pendant Drop Cryolite Experiments were undertaken because unsatisfactory choices of candidate materials were being made on the basis of a flawed set of selection criteria applied to an incomplete and sometimes inaccurate data base. This experiment was then constructed to determine whether the apparatus used for float zone crystal growth could be adapted to make a variety of important based melts and their interactions with candidate inert anode materials. Compositions), driven by our perception that the basis for prior selection of candidate materials was inadequate. Results are presented.

  6. Estimation method for serial dilution experiments.

    PubMed

    Ben-David, Avishai; Davidson, Charles E

    2014-12-01

    Titration of microorganisms in infectious or environmental samples is a corner stone of quantitative microbiology. A simple method is presented to estimate the microbial counts obtained with the serial dilution technique for microorganisms that can grow on bacteriological media and develop into a colony. The number (concentration) of viable microbial organisms is estimated from a single dilution plate (assay) without a need for replicate plates. Our method selects the best agar plate with which to estimate the microbial counts, and takes into account the colony size and plate area that both contribute to the likelihood of miscounting the number of colonies on a plate. The estimate of the optimal count given by our method can be used to narrow the search for the best (optimal) dilution plate and saves time. The required inputs are the plate size, the microbial colony size, and the serial dilution factors. The proposed approach shows relative accuracy well within ±0.1log10 from data produced by computer simulations. The method maintains this accuracy even in the presence of dilution errors of up to 10% (for both the aliquot and diluent volumes), microbial counts between 10(4) and 10(12) colony-forming units, dilution ratios from 2 to 100, and plate size to colony size ratios between 6.25 to 200. PMID:25205541

  7. Results of Waste Transfer and Back-Dilution in Tanks 241-SY-101 and 241-SY-102

    SciTech Connect

    LA Mahoney; ZI Antoniak; WB Barton; JM Conner; NW Kirch; CW Stewart; BE Wells

    2000-07-26

    This report chronicles the process of remediation of the flammable gas hazard in Tank 241-SY-101 (SY-101) by waste transfer and back-dilution from December 18, 1999 through April 2, 2000. A brief history is given of the development of the flammable gas retention and release hazard in this tank, and the transfer and dilution systems are outlined. A detailed narrative of each of the three transfer and dilution campaigns is given to provide structure for the balance of the report. Details of the behavior of specific data are then described, including the effect of transfer and dilution on the waste levels in Tanks SY-101 and SY-102, data from strain gauges on equipment suspended from the tank dome, changes in waste configuration as inferred from neutron and gamma logs, headspace gas concentrations, waste temperatures, and the mixerpump operating performance. Operating data and performance of the transfer pump in SY-101 are also discussed.

  8. Soil chemistry in lithologically diverse datasets: the quartz dilution effect

    USGS Publications Warehouse

    Bern, Carleton R.

    2009-01-01

    National- and continental-scale soil geochemical datasets are likely to move our understanding of broad soil geochemistry patterns forward significantly. Patterns of chemistry and mineralogy delineated from these datasets are strongly influenced by the composition of the soil parent material, which itself is largely a function of lithology and particle size sorting. Such controls present a challenge by obscuring subtler patterns arising from subsequent pedogenic processes. Here the effect of quartz concentration is examined in moist-climate soils from a pilot dataset of the North American Soil Geochemical Landscapes Project. Due to variable and high quartz contents (6.2–81.7 wt.%), and its residual and inert nature in soil, quartz is demonstrated to influence broad patterns in soil chemistry. A dilution effect is observed whereby concentrations of various elements are significantly and strongly negatively correlated with quartz. Quartz content drives artificial positive correlations between concentrations of some elements and obscures negative correlations between others. Unadjusted soil data show the highly mobile base cations Ca, Mg, and Na to be often strongly positively correlated with intermediately mobile Al or Fe, and generally uncorrelated with the relatively immobile high-field-strength elements (HFS) Ti and Nb. Both patterns are contrary to broad expectations for soils being weathered and leached. After transforming bulk soil chemistry to a quartz-free basis, the base cations are generally uncorrelated with Al and Fe, and negative correlations generally emerge with the HFS elements. Quartz-free element data may be a useful tool for elucidating patterns of weathering or parent-material chemistry in large soil datasets.

  9. Composition suitable for use as inert electrode having good electrical conductivity and mechanical properties

    DOEpatents

    Ray, Siba P. (Plum Boro, PA); Rapp, Robert A. (Columbus, OH)

    1984-01-01

    An improved inert electrode composition is suitable for use as an inert electrode in the production of metals such as aluminum by the electrolytic reduction of metal oxide or metal salt dissolved in a molten salt bath. The composition comprises one or more metals or metal alloys and metal compounds which may include oxides of the metals comprising the alloy. The alloy and metal compounds are interwoven in a network which provides improved electrical conductivity and mechanical strength while preserving the level of chemical inertness necessary for such an electrode to function satisfactorily.

  10. Composition suitable for use as inert electrode having good electrical conductivity and mechanical properties

    DOEpatents

    Ray, S.P.; Rapp, R.A.

    1984-06-12

    An improved inert electrode composition is suitable for use as an inert electrode in the production of metals such as aluminum by the electrolytic reduction of metal oxide or metal salt dissolved in a molten salt bath. The composition comprises one or more metals or metal alloys and metal compounds which may include oxides of the metals comprising the alloy. The alloy and metal compounds are interwoven in a network which provides improved electrical conductivity and mechanical strength while preserving the level of chemical inertness necessary for such an electrode to function satisfactorily. 8 figs.

  11. Inert anode containing base metal and noble metal useful for the electrolytic production of aluminum

    DOEpatents

    Ray, Siba P. (Murrysville, PA); Liu, Xinghua (Monroeville, PA)

    2000-01-01

    An inert anode for production of metals such as aluminum is disclosed. The inert anode comprises a base metal selected from Cu and Ag, and at least one noble metal selected from Ag, Pd, Pt, Au, Rh, Ru, Ir and Os. The inert anode may optionally be formed of sintered particles having interior portions containing more base metal than noble metal and exterior portions containing more noble metal than base metal. In a preferred embodiment, the base metal comprises Cu, and the noble metal comprises Ag, Pd or a combination thereof.

  12. Product characteristics from the torrefaction of oil palm fiber pellets in inert and oxidative atmospheres.

    PubMed

    Chen, Wei-Hsin; Zhuang, Yi-Qing; Liu, Shih-Hsien; Juang, Tarng-Tzuen; Tsai, Chi-Ming

    2016-01-01

    The aim of this work was to study the characteristics of solid and liquid products from the torrefaction of oil palm fiber pellets (OPFP) in inert and oxidative environments. The torrefaction temperature and O2 concentration in the carrier gas were in the ranges of 275-350°C and 0-10vol%, respectively, while the torrefaction duration was 30min. The oxidative torrefaction of OPFP at 275°C drastically intensified the HHV of the biomass when compared to the non-oxidative torrefaction. OPFP torrefied at 300°C is recommended to upgrade the biomass, irrespective of the atmosphere. The HHV of condensed liquid was between 10.1 and 13.2MJkg(-)(1), and was promoted to 23.2-28.7MJkg(-)(1) following dewatering. This accounts for 92-139% improvement in the calorific value of the liquid. This reveals that the recovery of condensed liquid with dewatering is able to enhance the energy efficiency of a torrefaction system. PMID:26346262

  13. Control of degradation of spent LWR (light-water reactor) fuel during dry storage in an inert atmosphere

    SciTech Connect

    Cunningham, M.E.; Simonen, E.P.; Allemann, R.T.; Levy, I.S.; Hazelton, R.F.

    1987-10-01

    Dry storage of Zircaloy-clad spent fuel in inert gas (referred to as inerted dry storage or IDS) is being developed as an alternative to water pool storage of spent fuel. The objectives of the activities described in this report are to identify potential Zircaloy degradation mechanisms and evaluate their applicability to cladding breach during IDS, develop models of the dominant Zircaloy degradation mechanisms, and recommend cladding temperature limits during IDS to control Zircaloy degradation. The principal potential Zircaloy cladding breach mechanisms during IDS have been identified as creep rupture, stress corrosion cracking (SCC), and delayed hydride cracking (DHC). Creep rupture is concluded to be the primary cladding breach mechanism during IDS. Deformation and fracture maps based on creep rupture were developed for Zircaloy. These maps were then used as the basis for developing spent fuel cladding temperature limits that would prevent cladding breach during a 40-year IDS period. The probability of cladding breach for spent fuel stored at the temperature limit is less than 0.5% per spent fuel rod. 52 refs., 7 figs., 1 tab.

  14. Dynamic properties of dilute Bose-Einstein condensates

    NASA Astrophysics Data System (ADS)

    Durfee, Dallin S.

    In this thesis, a new apparatus for the study of Bose- Einstein condensation is described, and the first two experiments performed with the new device are discussed. The new instrument was constructed for the creation of dilute gas sodium Bose-Einstein condensates, and features an optical quality quartz cell, a high-flux spin-flip Zeeman slower, a tightly confining magnetic trap, and a high-resolution imaging system. The theory, design, and construction of each component is discussed, including a detailed explanation of non-destructive dispersive imaging. Bose-Einstein condensation was first achieved in the new apparatus in January of this year. Bose condensates consisting of 10 to 25 million atoms can be produced in this apparatus at a rate of two condensates per minute. The first two experiments performed with the new instrument probed the dynamic properties of dilute Bose condensates, allowing comparisons to be made with long standing theories of weakly-interacting degenerate Bose fluids. The first experiment was the study of ``surface wave'' excitations of Bose condensates. Standing and rotating quadrupole and octopole excitations were driven with a novel scanned optical dipole potential, a new tool which allows us to generate arbitrary two-dimensional perturbations to the trapping potential which confines the atoms. The second experiment studied the transition from dissipationless to dissipative flow in a Bose condensate. This study, performed by ``stirring'' the condensate with a focused laser, provided the first experimental evidence for the existence of a critical velocity for dissipation in dilute gas Bose condensates. This experiment is discussed in the context of earlier studies of the critical velocity of superfluid liquid helium. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

  15. Growth and characterization of dilute nitride GaNxP1-x nanowires and GaNxP1-x/GaNyP1-y core/shell nanowires on Si (111) by gas source molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Sukrittanon, S.; Kuang, Y. J.; Dobrovolsky, A.; Kang, Won-Mo; Jang, Ja-Soon; Kim, Bong-Joong; Chen, W. M.; Buyanova, I. A.; Tu, C. W.

    2014-08-01

    We have demonstrated self-catalyzed GaNxP1-x and GaNxP1-x/GaNyP1-y core/shell nanowire growth by gas-source molecular beam epitaxy. The growth window for GaNxP1-x nanowires was observed to be comparable to that of GaP nanowires (˜585 °C to ˜615 °C). Transmission electron microscopy showed a mixture of cubic zincblende phase and hexagonal wurtzite phase along the [111] growth direction in GaNxP1-x nanowires. A temperature-dependent photoluminescence (PL) study performed on GaNxP1-x/GaNyP1-y core/shell nanowires exhibited an S-shape dependence of the PL peaks. This suggests that at low temperature, the emission stems from N-related localized states below the conduction band edge in the shell, while at high temperature, the emission stems from band-to-band transition in the shell as well as recombination in the GaNxP1-x core.

  16. 40 CFR 86.110-90 - Exhaust gas sampling system; diesel vehicles.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...on the probe. The sensor shall have an accuracy...The dilute exhaust gas flowing in the total...sample line. The sensor shall have an accuracy...the dilute exhaust gas flowing in the total...on the probe. The sensor shall have an accuracy...The dilute exhaust gas flowing in the...

  17. Thermal conductivity and sound attenuation in dilute atomic Fermi gases

    SciTech Connect

    Braby, Matt; Chao Jingyi; Schaefer, Thomas

    2010-09-15

    We compute the thermal conductivity and sound attenuation length of a dilute atomic Fermi gas in the framework of kinetic theory. Above the critical temperature for superfluidity, T{sub c}, the quasiparticles are fermions, whereas below T{sub c}, the dominant excitations are phonons. We calculate the thermal conductivity in both cases. We find that at unitarity the thermal conductivity {kappa} in the normal phase scales as {kappa}{proportional_to}T{sup 3/2}. In the superfluid phase we find {kappa}{proportional_to}T{sup 2}. At high temperature the Prandtl number, the ratio of the momentum and thermal diffusion constants, is 2/3. The ratio increases as the temperature is lowered. As a consequence we expect sound attenuation in the normal phase just above T{sub c} to be dominated by shear viscosity. We comment on the possibility of extracting the shear viscosity of the dilute Fermi gas at unitarity using measurements of the sound absorption length.

  18. Bose-Einstein Condensation in a Dilute Atomic Vapor

    NASA Astrophysics Data System (ADS)

    Cornell, Eric

    1996-05-01

    We observe Bose-Einstein condensation in a dilute atomic gas cooled below 170 nK. footnote In collaboration with M. H. Anderson, J. R. Ensher, D. S. Jin, M. R. Matthews, and C. E. Wieman We optically trap and pre-cool ^87Rb from a background vapor, then load the atoms into a magnetic trap. To reach the temperature and density requirements for the phase transition to BEC, we further cool the atoms by evaporation, releasing higher energy atoms from the trap with a radio frequency magnetic field. Velocity distributions characteristic of BEC are observed by allowing the atoms to expand and then imaging a shadow of the cloud onto a charge-coupled device array. BEC in a dilute, and hence weakly interacting, gas has the advantage that its properties may be explored theoretically in terms of basic interatomic interactions, whereas the properties of related phenomena such as superconductivity in metals and superfluidity in liquid He are fundamentally modified by strong interparticle interactions. We discuss progress in probing BEC in Rb atoms. One way to study the effect of interactions is to compare the behaviors of ^87Rb and ^85Rb. ^85Rb is known to have a negative scattering length footnote J. R. Gardner, et al., Phys. Rev. Lett. 74, 3764 (1995). (attractive interparticle interaction) which is expected to make the BEC unstable for large numbers of atoms. Another direction of our work is to look for excitations of the condensate.

  19. Figure 1). Physically inert, tangible objects are used on the table; these are conventional rubber toys

    E-print Network

    Baldassarri, Sandra

    Figure 1). Physically inert, tangible objects are used on the table; these are conventional rubber-year-olds. Therefore, we bought some rubber farm animals and modeled a 3-D virtual farm with animal avatars as inputs

  20. 30 CFR 75.1107-12 - Inerting of mine atmosphere prohibited.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Fire Protection Fire Suppression Devices and Fire-Resistant Hydraulic Fluids on Underground Equipment § 75.1107-12 Inerting of mine atmosphere prohibited. No fire suppression...

  1. Energy levels of the electrons localized over the surface of an inert film with address electrodes

    SciTech Connect

    Petrin, A. B.

    2013-03-15

    The problem of searching for the potential energy and the energy spectrum of the electrons localized over the surface of a thin liquid or solid inert film due to address electrodes placed under the film is considered.

  2. For cermet inert anode containing oxide and metal phases useful for the electrolytic production of metals

    DOEpatents

    Ray, Siba P. (Murrysville, PA); Liu, Xinghua (Monroeville, PA); Weirauch, Douglas A. (Murrysville, PA)

    2002-01-01

    A cermet inert anode for the electrolytic production of metals such as aluminum is disclosed. The inert anode comprises a ceramic phase including an oxide of Ni, Fe and M, where M is at least one metal selected from Zn, Co, Al, Li, Cu, Ti, V, Cr, Zr, Nb, Ta, W, Mo, Hf and rare earths, preferably Zn and/or Co. Preferred ceramic compositions comprise Fe.sub.2 O.sub.3, NiO and ZnO or CoO. The cermet inert anode also comprises a metal phase such as Cu, Ag, Pd, Pt, Au, Rh, Ru, Ir and/or Os. A preferred metal phase comprises Cu and Ag. The cermet inert anodes may be used in electrolytic reduction cells for the production of commercial purity aluminum as well as other metals.

  3. Inert anode containing oxides of nickel iron and cobalt useful for the electrolytic production of metals

    DOEpatents

    Ray, Siba P. (Murrysville, PA); Liu, Xinghua (Monroeville, PA); Weirauch, Jr., Douglas A. (Murrysville, PA)

    2002-01-01

    An inert anode for the electrolytic production of metals such as aluminum is disclosed. The inert anode includes a ceramic oxide material preferably made from NiO, Fe.sub.2 O.sub.3 and CoO. The inert anode composition may comprise the following mole fractions of NiO, Fe.sub.2 O.sub.3 and CoO: 0.15 to 0.99 NiO; 0.0001 to 0.85 Fe.sub.2 O.sub.3 ; and 0.0001 to 0.45 CoO. The inert anode may optionally include other oxides and/or at least one metal phase, such as Cu, Ag, Pd, Pt, Au, Rh, Ru, Ir and/or Os. The Ni--Fe--Co--O ceramic material exhibits very low solubility in Hall cell baths used to produce aluminum.

  4. Inert anode containing oxides of nickel, iron and zinc useful for the electrolytic production of metals

    DOEpatents

    Ray, Siba P. (Murrysville, PA); Weirauch, Jr., Douglas A. (Murrysville, PA); Liu, Xinghua (Monroeville, PA)

    2002-01-01

    An inert anode for the electrolytic production of metals such as aluminum is disclosed. The inert anode includes a ceramic oxide material preferably made from NiO, Fe.sub.2 O.sub.3 and ZnO. The inert anode composition may comprise the following mole fractions of NiO, Fe.sub.2 O.sub.3 and ZnO: 0.2 to 0.99 NiO; 0.0001 to 0.8 Fe.sub.2 O.sub.3 ; and 0.0001 to 0.3 ZnO. The inert anode may optionally include other oxides and/or at least one metal phase, such as Cu, Ag, Pd, Pt, Au, Rh, Ru, Ir and/or Os. The Ni--Fe--Co--O ceramic material exhibits very low solubility in Hall cell baths used to produce aluminum.

  5. Lepton Flavor Violation in the Inert Scalar Model with Higher Representations

    E-print Network

    Talal Ahmed Chowdhury; Salah Nasri

    2015-05-31

    We investigate the lepton flavor violation (LFV) in the inert scalar model with higher representations. We generalize the inert doublet model with right handed neutrino by using higher scalar and fermion representation of $SU(2)_{L}$. As the generalized model and the inert doublet model have the same parameter space, we compare the rates of $\\mu\\rightarrow e\\gamma$, $\\mu\\rightarrow ee\\overline{e}$ and $\\mu-e$ conversion in nuclei in the doublet and its immediate extension, the quartet model. We show that the corresponding rates are larger in the case of higher representation compared to the Inert doublet for the same region of parameter space. This implies that such extended models are more constrained by current LFV bounds and will have better prospects in future experiments.

  6. Clamp and Gas Nozzle for TIG Welding

    NASA Technical Reports Server (NTRS)

    Gue, G. B.; Goller, H. L.

    1982-01-01

    Tool that combines clamp with gas nozzle is aid to tungsten/inert-gas (TIG) welding in hard-to-reach spots. Tool holds work to be welded while directing a stream of argon gas at weld joint, providing an oxygen-free environment for tungsten-arc welding.

  7. The Bogoliubov free energy functional II. The dilute limit

    E-print Network

    Marcin Napiórkowski; Robin Reuvers; Jan Philip Solovej

    2015-11-18

    We analyse the canonical Bogoliubov free energy functional at low temperatures in the dilute limit. We prove existence of a first order phase transition and, in the limit $a_0\\to a$, we determine the critical temperature to be $T_{\\rm{c}}=T_{\\rm{fc}}(1+1.49(\\rho^{1/3}a))$ to leading order. Here, $T_{\\rm{fc}}$ is the critical temperature of the free Bose gas, $\\rho$ is the density of the gas, $a$ is the scattering length of the pair-interaction potential $V$, and $a_0=(8\\pi)^{-1}\\widehat{V}(0)$ its first order approximation. We also prove asymptotic expansions for the free energy. In particular, we recover the Lee-Huang-Yang formula in the limit $a_0\\to a$.

  8. Spin dynamics in paramagnetic diluted magnetic semiconductors

    NASA Astrophysics Data System (ADS)

    Phan, Van-Nham; Tran, Minh-Tien

    2015-10-01

    Microscopic properties of low-energy spin dynamics in diluted magnetic semiconductor are addressed in a framework of the Kondo lattice model including random distribution of magnetic dopants. Based on the fluctuation-dissipation theorem, we derive an explicit dependence of the spin diffusion coefficient on the single-particle Green function which is directly evaluated by dynamical mean-field theory. In the paramagnetic state, the magnetic scattering has been manifested to suppress spin diffusion. In agreement with other ferromagnet systems, we also point out that the spin diffusion in diluted magnetic semiconductors at small carrier concentration displays a monotonic 1 /T -like temperature dependence. By investigating the spin diffusion coefficient on a wide range of the model parameters, the obtained results have provided a significant scenario to understand the spin dynamics in the paramagnetic diluted magnetic semiconductors.

  9. Henry's law, surface tension, and surface adsorption in dilute binary mixtures

    E-print Network

    Henry's law, surface tension, and surface adsorption in dilute binary mixtures Akira Onukia. The solute partitioning between gas and liquid Henry's law and the surface tension change are discussed fraction X and the temperature-derivative / T cx,p of the surface tension at fixed pressure p

  10. Bose-Einstein condensation in dilute atomic gases: atomic physics meets condensed matter physics

    E-print Network

    of quantum fluids. They are produced by cooling a dilute atomic gas to nanokelvin temperatures using laser and immiscibility of quantum fluids, and finite-size effects. Keywords: Bose-Einstein condensation; collective. Ketterle Department of Physics and Research Laboratory of Electronics, Massachusetts Institute

  11. Peptide derived from Pvfp-1 as bioadhesive on bio-inert surface.

    PubMed

    Jiang, Zhen; Yu, Yabiao; Du, Lina; Ding, Xiyu; Xu, Hui; Sun, Yanan; Zhang, Qiqing

    2012-02-01

    Surface property is one important characteristic of materials, especially for ones that are bio-inert but designed for bio-medical application. In this study, we designed a series of peptides and compared their capacities as bioadhesive to improve the surface bioactivity of bio-inert material. The peptides were designed according to the sequence of Perna viridis foot protein 1 (Pvfp-1), one of the Mfp-1s (mussel foot protein 1) which play key roles in wet adhesion of mussel byssus. And the Teflon (PTFE) was chosen as a model of bio-inert material. With adsorption, adhesion and coating analysis, it was found that peptide C2 (M) (derived from the non-repeating region of Pvfp-1, contains modified DOPA) has superior coating and adhesion abilities especially on the bio-inert surface of PTFE. After coating with peptide C2 (M), the cell adhesion and spreading of osteoblast MC3T3-E1 cells on PTFE were significantly improved compared with those on non-coated surface, and the peptide-coating did not show any cell toxicity. Therefore, peptide C2 (M) is effective for improving the bioactivity of bio-inert PTFE, and could be potentially used as a bioadhesive on other bio-inert materials for biomedical application. Moreover, this study also provided new insights in designing other peptide-based bioadhesive materials. PMID:22079698

  12. Experiments in dilution jet mixing

    NASA Technical Reports Server (NTRS)

    Holdeman, J. D.; Srinivasan, R.; Berenfeld, A.

    1983-01-01

    Experimental results are given on the mixing of a single row of jets with an isothermal mainstream in a straight duct, to include flow and geometric variations typical of combustion chambers in gas turbine engines. The principal conclusions reached from these experiments were: at constant momentum ratio, variations in density ratio have only a second-order effect on the profiles; a first-order approximation to the mixing of jets with a variable temperature mainstream can be obtained by superimposing the jets-in-an isothermal-crossflow and mainstream profiles; flow area convergence, especially injection-wall convergence, significantly improves the mixing; for opposed rows of jets, with the orifice centerlines in-line, the optimum ratio of orifice spacing to duct height is one half of the optimum value for single side injection at the same momentum ratio; and for opposed rows of jets, with the orifice centerlines staggered, the optimum ratio of orifice spacing to duct height is twice the optimum value for single side injection at the same momentum ratio.

  13. Diluted magnetic semiconductor nanowires exhibiting magnetoresistance

    DOEpatents

    Yang, Peidong (El Cerrito, CA); Choi, Heonjin (Seoul, KR); Lee, Sangkwon (Daejeon, KR); He, Rongrui (Albany, CA); Zhang, Yanfeng (El Cerrito, CA); Kuykendal, Tevye (Berkeley, CA); Pauzauskie, Peter (Berkeley, CA)

    2011-08-23

    A method for is disclosed for fabricating diluted magnetic semiconductor (DMS) nanowires by providing a catalyst-coated substrate and subjecting at least a portion of the substrate to a semiconductor, and dopant via chloride-based vapor transport to synthesize the nanowires. Using this novel chloride-based chemical vapor transport process, single crystalline diluted magnetic semiconductor nanowires Ga.sub.1-xMn.sub.xN (x=0.07) were synthesized. The nanowires, which have diameters of .about.10 nm to 100 nm and lengths of up to tens of micrometers, show ferromagnetism with Curie temperature above room temperature, and magnetoresistance up to 250 Kelvin.

  14. Automatic dilution gaging of rapidly varying flow

    USGS Publications Warehouse

    Duerk, M.D.

    1983-01-01

    The analysis showed that the discharges measured by dye-dilution techniques were generally within ± 10 percent of the discharges determined from ratings established by current-meter measurements. Larger differences were noted at the start of and on the rising limb of four hydrographs. Of the 20 storms monitored, dilution measurements on 17 were of acceptable accuracy. Peak discharges from the open-channel site ranged from 0 to 12 percent departures from the existing rating whereas the comparison of peak discharge at the storm sewer site ranged from 0 to 5 percent departures from the existing rating.

  15. Standard for Inert Cryogenic Liquid Usage in the Laboratory Page 1 of 4 Standard for Inert Cryogenic Liquid Usage in the Laboratory

    E-print Network

    Chan, Hue Sun

    Cryogenic Liquid Usage in the Laboratory Page 1 of 4 March 2009 Standard for Inert Cryogenic Liquid Usage in the Laboratory In University workplaces, the storage, handling and dispensing of cryogenic liquids (e.g. liquid-up. Appropriate controls must be implemented wherever cryogenics are in use. This standard outlines some general

  16. Transport properties of pristine few-layer black phosphorus by van der Waals passivation in an inert atmosphere.

    PubMed

    Doganov, Rostislav A; O'Farrell, Eoin C T; Koenig, Steven P; Yeo, Yuting; Ziletti, Angelo; Carvalho, Alexandra; Campbell, David K; Coker, David F; Watanabe, Kenji; Taniguchi, Takashi; Castro Neto, Antonio H; Özyilmaz, Barbaros

    2015-01-01

    Ultrathin black phosphorus is a two-dimensional semiconductor with a sizeable band gap. Its excellent electronic properties make it attractive for applications in transistor, logic and optoelectronic devices. However, it is also the first widely investigated two-dimensional material to undergo degradation upon exposure to ambient air. Therefore a passivation method is required to study the intrinsic material properties, understand how oxidation affects the physical properties and enable applications of phosphorene. Here we demonstrate that atomically thin graphene and hexagonal boron nitride can be used for passivation of ultrathin black phosphorus. We report that few-layer pristine black phosphorus channels passivated in an inert gas environment, without any prior exposure to air, exhibit greatly improved n-type charge transport resulting in symmetric electron and hole transconductance characteristics. PMID:25858614

  17. Transport properties of pristine few-layer black phosphorus by van der Waals passivation in an inert atmosphere

    NASA Astrophysics Data System (ADS)

    Doganov, Rostislav A.; O'Farrell, Eoin C. T.; Koenig, Steven P.; Yeo, Yuting; Ziletti, Angelo; Carvalho, Alexandra; Campbell, David K.; Coker, David F.; Watanabe, Kenji; Taniguchi, Takashi; Neto, Antonio H. Castro; Özyilmaz, Barbaros

    2015-04-01

    Ultrathin black phosphorus is a two-dimensional semiconductor with a sizeable band gap. Its excellent electronic properties make it attractive for applications in transistor, logic and optoelectronic devices. However, it is also the first widely investigated two-dimensional material to undergo degradation upon exposure to ambient air. Therefore a passivation method is required to study the intrinsic material properties, understand how oxidation affects the physical properties and enable applications of phosphorene. Here we demonstrate that atomically thin graphene and hexagonal boron nitride can be used for passivation of ultrathin black phosphorus. We report that few-layer pristine black phosphorus channels passivated in an inert gas environment, without any prior exposure to air, exhibit greatly improved n-type charge transport resulting in symmetric electron and hole transconductance characteristics.

  18. Sulfate and organic matter concentration in relation to hydrogen sulfide generation at inert solid waste landfill site - Limit value for gypsum.

    PubMed

    Asakura, Hiroshi

    2015-09-01

    In order to suggest a limit value for gypsum (CaSO4) for the suppression of hydrogen sulfide (H2S) generation at an inert solid waste landfill site, the relationship between raw material (SO4 and organic matter) for H2S generation and generated H2S concentration, and the balance of raw material (SO4) and product (H2S) considering generation and outflow were investigated. SO4 concentration should be less than approximately 100mg-SO4/L in order to suppress H2S generation to below 2000ppm. Total organic carbon (TOC) concentration should be less than approximately 200mg-C/L assuming a high SO4 concentration. The limit value for SO4 in the ground is 60mg-SO4/kg with 0.011wt% as gypsum dihydrate, i.e., approximately 1/10 of the limit value in inert waste as defined by the EU Council Decision (560mg-SO4/kg-waste). The limit value for SO4 in inert waste as defined by the EU Council Decision is high and TOC is strictly excluded. The cumulative amount of SO4 outflow through the liquid phase is much larger than that through the gas phase. SO4 concentration in pore water decreases with time, reaching half the initial concentration around day 100. SO4 reduction by rainfall can be expected in the long term. PMID:26123977

  19. Geochemical detection of carbon dioxide in dilute aquifers

    PubMed Central

    2009-01-01

    Background Carbon storage in deep saline reservoirs has the potential to lower the amount of CO2 emitted to the atmosphere and to mitigate global warming. Leakage back to the atmosphere through abandoned wells and along faults would reduce the efficiency of carbon storage, possibly leading to health and ecological hazards at the ground surface, and possibly impacting water quality of near-surface dilute aquifers. We use static equilibrium and reactive transport simulations to test the hypothesis that perturbations in water chemistry associated with a CO2 gas leak into dilute groundwater are important measures for the potential release of CO2 to the atmosphere. Simulation parameters are constrained by groundwater chemistry, flow, and lithology from the High Plains aquifer. The High Plains aquifer is used to represent a typical sedimentary aquifer overlying a deep CO2 storage reservoir. Specifically, we address the relationships between CO2 flux, groundwater flow, detection time and distance. The CO2 flux ranges from 103 to 2 × 106 t/yr (0.63 to 1250 t/m2/yr) to assess chemical perturbations resulting from relatively small leaks that may compromise long-term storage, water quality, and surface ecology, and larger leaks characteristic of short-term well failure. Results For the scenarios we studied, our simulations show pH and carbonate chemistry are good indicators for leakage of stored CO2 into an overlying aquifer because elevated CO2 yields a more acid pH than the ambient groundwater. CO2 leakage into a dilute groundwater creates a slightly acid plume that can be detected at some distance from the leak source due to groundwater flow and CO2 buoyancy. pH breakthrough curves demonstrate that CO2 leaks can be easily detected for CO2 flux ? 104 t/yr within a 15-month time period at a monitoring well screened within a permeable layer 500 m downstream from the vertical gas trace. At lower flux rates, the CO2 dissolves in the aqueous phase in the lower most permeable unit and does not reach the monitoring well. Sustained pumping in a developed aquifer mixes the CO2-affected water with the ambient water and enhances pH signal for small leaks (103 t/yr) and reduces pH signal for larger leaks (? 104t/yr). Conclusion The ability to detect CO2 leakage from a storage reservoir to overlying dilute groundwater is dependent on CO2 solubility, leak flux, CO2 buoyancy, and groundwater flow. Our simulations show that the most likely places to detect CO2 are at the base of the confining layer near the water table where CO2 gas accumulates and is transported laterally in all directions, and downstream of the vertical gas trace where groundwater flow is great enough to transport dissolved CO2 laterally. Our simulations show that CO2 may not rise high enough in the aquifer to be detected because aqueous solubility and lateral groundwater transport within the lower aquifer unit exceeds gas pressure build-up and buoyancy needed to drive the CO2 gas upwards. PMID:19323832

  20. Efficient isolation of multiphoton processes and detection of collective states in dilute samples

    E-print Network

    Bruder, Lukas; Stienkemeier, Frank

    2015-01-01

    A novel technique to sensitively and selectively isolate multiple-quantum coherences in a femtosecond pump-probe setup is presented. Detecting incoherent observables and imparting lock-in amplification, even weak signals of highly dilute samples can be acquired. Applying this method, efficient isolation of one- and two-photon transitions in a rubidium-doped helium droplet beam experiment is demonstrated and collective resonances up to fourth order are observed in a potassium vapor for the first time. Our approach provides new perspectives for coherent experiments in the deep UV and novel multidimensional spectroscopy schemes, in particular when selective detection of particles in dilute gas-phase targets is possible.

  1. Dilute nitride InNP quantum dots: Growth and photoluminescence mechanism

    SciTech Connect

    Kuang, Y. J.; Takabayashi, K.; Kamiya, I.; Sukrittanon, S.; Pan, J. L.; Tu, C. W.

    2014-10-27

    Self-assembled dilute nitride InNP quantum dots (QDs) in GaP matrix grown under the Stranski-Krastanov mode by gas-source molecular beam epitaxy are studied. The N-related localized states inside the InNP QDs provide a spatially direct recombination channel, in contrast to the spatially indirect channel through the strained In(N)P QDs/GaP interface states. The N incorporation into InP QDs therefore causes a blueshift and double-peak features in photoluminescence, which are not observed in other dilute nitride materials.

  2. Dilute nitride InNP quantum dots: Growth and photoluminescence mechanism

    NASA Astrophysics Data System (ADS)

    Kuang, Y. J.; Takabayashi, K.; Sukrittanon, S.; Pan, J. L.; Kamiya, I.; Tu, C. W.

    2014-10-01

    Self-assembled dilute nitride InNP quantum dots (QDs) in GaP matrix grown under the Stranski-Krastanov mode by gas-source molecular beam epitaxy are studied. The N-related localized states inside the InNP QDs provide a spatially direct recombination channel, in contrast to the spatially indirect channel through the strained In(N)P QDs/GaP interface states. The N incorporation into InP QDs therefore causes a blueshift and double-peak features in photoluminescence, which are not observed in other dilute nitride materials.

  3. Serial dilution microchip for cytotoxicity test

    NASA Astrophysics Data System (ADS)

    Bang, Hyunwoo; Lim, Sun Hee; Lee, Young Kyung; Chung, Seok; Chung, Chanil; Han, Dong-Chul; Chang, Jun Keun

    2004-08-01

    Today's pharmaceutical industry is facing challenges resulting from the vast increases in sample numbers produced by high-throughput screening (HTS). In addition, the bottlenecks created by increased demand for cytotoxicity testing (required to assess compound safety) are becoming a serious problem. We have developed a polymer PDMS (polydimethylsiloxane) based microfluidic device that can perform a cytotoxicity test in a rapid and reproducible manner. The concept that the device includes is well adjustable to automated robots in huge HTS systems, so we can think of it as a potential dilution and delivery module. Cytotoxicity testing is all about the dilution and dispensing of a drug sample. Previously, we made a PDMS based microfluidic device which automatically and precisely diluted drugs with a buffer solution with serially increasing concentrations. This time, the serially diluted drug solution was directly delivered to 96 well plates for cytotoxicity testing. Cytotoxic paclitaxel solution with 2% RPMI 1640 has been used while carrying out cancerous cell based cytotoxicity tests. We believe that this rapid and robust use of the PDMS microchip will overcome the growing problem in cytotoxicity testing for HTS.

  4. LAKE RESTORATION BY DILUTION: MOSES LAKE, WASHINGTON

    EPA Science Inventory

    Dilution water, low in macronutrients, was added to Moses Lake on three occasions in 1977 and once in 1978 during the spring-summer period. The addition resulted in reducing the annual average inflow concentration of phosphorus from about 130-140 micrograms/l to 100 micrograms/l....

  5. Sulfuric Acid and Water: Paradoxes of Dilution

    ERIC Educational Resources Information Center

    Leenson, I. A.

    2004-01-01

    On equilibrium properties of aqueous solutions of sulfuric acid, Julius Thomsen has marked that the heat evolved on diluting liquid sulfuric acid with water is a continuous function of the water used, and excluded absolutely the acceptance of definite hydrates as existing in the solution. Information about thermochemical measurement, a discussion…

  6. THE MOST DILUTE LAKE IN THE WORLD?

    EPA Science Inventory

    Lake Notasha, near the crest of the Oregon Cascade mountain range, is the most dilute lake known. he measured conductivity during two visits was 1.3 and 1.6 uS cm-1, with a sum of base cations of 9 and 18 ueq L-1; bicarbonate was the dominant anion. ost of the cations in the lake...

  7. Improved Assembly for Gas Shielding During Welding or Brazing

    NASA Technical Reports Server (NTRS)

    Gradl, Paul; Baker, Kevin; Weeks, Jack

    2009-01-01

    An improved assembly for inert-gas shielding of a metallic joint is designed to be useable during any of a variety of both laser-based and traditional welding and brazing processes. The basic purpose of this assembly or of a typical prior related assembly is to channel the flow of a chemically inert gas to a joint to prevent environmental contamination of the joint during the welding or brazing process and, if required, to accelerate cooling upon completion of the process.

  8. A simple deep monitoring well dilution technique.

    NASA Astrophysics Data System (ADS)

    Rogiers, Bart; Labat, Serge; Gedeon, Matej; Vandersteen, Katrijn

    2015-04-01

    Well dilution techniques are well known and studied as one of the basic techniques to quantify groundwater fluxes. A typical well dilution test consists of the injection of a tracer, a mixing mechanism (e.g. water circulation with a pump) to achieve a homogeneous concentration distribution within the well, and monitoring of the evolution of tracer concentration with time. An apparent specific discharge can be obtained from such a test, and when details on the well construction are known, it can be converted into a specific discharge representative of the undisturbed aquifer. For deep wells however, the injection of tracer becomes less practical and the use of pumps for circulating and mixing the water becomes problematic. This is due to the limited pressure that common pumps can endure at the outlet, as well as the large volume of water that makes it difficult to achieve a homogeneous concentration, and the impracticalities of getting a lot of equipment to large depths in very small monitoring wells. Injection and monitoring of tracer at a specific depth omits several of the problems with deep wells. We present a very simple device that can be used to perform a dilution test at a specific depth in deep wells. The injection device consists of a PVC tube with a detachable rubber seal at its bottom. To minimize disturbance of the water column in the well, we integrated an EC sensor in this injection device, which enables us to use demineralized water or dissolved salts as a tracer. Once at the target depth, the PVC tube is retracted and the EC sensor and tracer become subject to groundwater flow. The device was tested on a shallow well, on which different types of dilution tests were performed. The results of the other tests agree well with the injection tube results. Finally, the device was used to perform a dilution test in a deep well in order to demonstrate the feasibility of the approach.

  9. Waste gas storage

    NASA Technical Reports Server (NTRS)

    Vickers, Brian D. (Inventor)

    1994-01-01

    Method for storing a waste gas mixture comprised of nitrogen, oxygen, carbon dioxide, and inert gases, the gas mixture containing corrosive contaminants including inorganic acids and bases and organic solvents, and derived from space station operations. The gas mixture is stored under pressure in a vessel formed of a filament wound composite overwrap on a metal liner, the metal liner being pre-stressed in compression by the overwrap, thereby avoiding any tensile stress in the liner, and preventing stress corrosion cracking of the liner during gas mixture storage.

  10. Geochemical detection of carbon dioxide in dilute aquifers

    SciTech Connect

    Carroll, S; Hao, Y; Aines, R

    2009-03-27

    Carbon storage in deep saline reservoirs has the potential to lower the amount of CO{sub 2} emitted to the atmosphere and to mitigate global warming. Leakage back to the atmosphere through abandoned wells and along faults would reduce the efficiency of carbon storage, possibly leading to health and ecological hazards at the ground surface, and possibly impacting water quality of near-surface dilute aquifers. We use static equilibrium and reactive transport simulations to test the hypothesis that perturbations in water chemistry associated with a CO{sub 2} gas leak into dilute groundwater are important measures for the potential release of CO{sub 2} to the atmosphere. Simulation parameters are constrained by groundwater chemistry, flow, and lithology from the High Plains aquifer. The High Plains aquifer is used to represent a typical sedimentary aquifer overlying a deep CO{sub 2} storage reservoir. Specifically, we address the relationships between CO{sub 2} flux, groundwater flow, detection time and distance. The CO{sub 2} flux ranges from 10{sup 3} to 2 x 10{sup 6} t/yr (0.63 to 1250 t/m{sup 2}/yr) to assess chemical perturbations resulting from relatively small leaks that may compromise long-term storage, water quality, and surface ecology, and larger leaks characteristic of short-term well failure.

  11. [Measurement of diffusion coefficients of polar solvent and nonpolar solvent at infinite dilution in polyethylene].

    PubMed

    Bian, Yu; Li, Ji-Ding; Chen, Cui-Xian; Lü, Shao-Hua; Zhang, Shu-Hua

    2002-09-01

    Gas chromatography is a new, fast, accurate and convenient technique to study the correlation of small molecule solvents and polymer membrane materials. It can measure many parameters of dissolution and diffusing characters of a small molecule in a polymer. The retention times and the peak widths at half-height of five small molecule solvents (n-hexane, n-heptane, n-decane, ethanol and water) in the stationary phase of polyethylene were measured. The diffusion coefficients of the small molecule solvents at infinite dilution were calculated with van Deemter equation. The graph plotted according to the results of the diffusion coefficients of n-decane at infinite dilution vs temperatures agreed with the Arrhenius equation. The variance in the diffusion coefficients at infinite dilution of five small molecule solvents was analyzed according to the differences in molecular mass and polarity. PMID:16358690

  12. Dilution in elliptical galaxies: implications for the relation between metallicity, stellar mass and star formation rate

    NASA Astrophysics Data System (ADS)

    Yates, Robert M.; Kauffmann, Guinevere

    2014-04-01

    We investigate whether dilution in some elliptical galaxies is the cause of a positive correlation between specific star formation rate (sSFR) and gas-phase metallicity (Zg) at high stellar mass in the local Universe. In the Munich semi-analytic model of galaxy formation, L-GALAXIES, massive, low-sSFR, elliptical galaxies are seen to undergo a gradual dilution of their interstellar medium, via accretion of metal-poor gas in cold-gas clumps and low-mass satellites. This occurs after a merger-induced starburst and the associated supernova feedback have quenched most of the original gas reservoir. Signatures of this evolution are present in these model galaxies at z = 0, including low gas fractions, large central black holes, old ages, and importantly, low (Zg-Z*). Remarkably, all of these properties are also found in massive, low-sSFR, elliptical galaxies in the sloan digital sky survey data release 7 (SDSS-DR7). This provides strong, indirect evidence that gradual dilution is also occurring in nearby ellipticals in the real Universe. This scenario provides an explanation for the positive correlation between SFR and Zg measured in high-M* galaxies, and therefore has consequences for the local fundamental metallicity relation, which assumes a weak anticorrelation above ˜1010.5 M?.

  13. 40 CFR 1065.667 - Dilution air background emission correction.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 2010-07-01 false Dilution air background emission correction...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Requirements § 1065.667 Dilution air background emission...

  14. 40 CFR 1066.610 - Dilution air background correction.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 2014-07-01 false Dilution air background correction. 1066.610...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS VEHICLE-TESTING PROCEDURES...Calculations § 1066.610 Dilution air background correction....

  15. 40 CFR 1065.667 - Dilution air background emission correction.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 2014-07-01 false Dilution air background emission correction...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Requirements § 1065.667 Dilution air background emission...

  16. 40 CFR 1065.667 - Dilution air background emission correction.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 2012-07-01 false Dilution air background emission correction...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Requirements § 1065.667 Dilution air background emission...

  17. 40 CFR 1065.667 - Dilution air background emission correction.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 2011-07-01 false Dilution air background emission correction...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Requirements § 1065.667 Dilution air background emission...

  18. 40 CFR 1065.667 - Dilution air background emission correction.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 2013-07-01 false Dilution air background emission correction...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Requirements § 1065.667 Dilution air background emission...

  19. A ``Dilution Refrigerator'' Using Spin-Polarized Fermions

    NASA Astrophysics Data System (ADS)

    Basu, Sourish; Mueller, Erich J.

    2009-05-01

    We present an analogy between a population imbalanced two component Fermi gas on the BEC side of a Feshbach resonance and a ^3He-^4He mixture. The bosonic pairs are analogous to ^4He and the fermionic unpaired atoms to ^3He. These systems have topologically indistinguishable phase diagrams: at low temperatures the system phase separates into a fermion rich and a fermion poor region. As in standard cryogenic setups, one can in principle create a refrigerator which cools based upon the fact that there is a latent heat associated with pulling particles from the fermion rich region into the fermion poor one. We explore this idea, calculating the entropy of mixing, and suggesting cold atom geometries which mimic the anatomy of a standard ^3He-^4He dilution refrigerator.

  20. The viscosity of dilute Bose-Einstein condensates

    NASA Astrophysics Data System (ADS)

    Gust, Erich D.; Reichl, L. E.

    2015-10-01

    The viscosity of a dilute Bose-Einstein condensate is obtained for a range of temperatures and densities. The kinetic equation used to derive the viscosity is based on Bogoliubov mean field theory and is a Boltzmann-like equation for the Bogoliubov excitations in the condensate. The viscosity can be assigned a numerical value for any gas for which the mass and scattering length are known. The viscosity decreases slowly as the temperature is decreased, but at low temperature (around 0.01 Tc), begins to show a much more rapid decrease with decreasing temperature. This interesting behavior of the viscosity is related to the behavior of the eigenvalues of the bogolon collision operator at these low temperatures.

  1. Helium 3/Helium 4 dilution cryocooler for space

    NASA Technical Reports Server (NTRS)

    Hendricks, John B.; Dingus, Michael L.

    1991-01-01

    Prototype dilution cryocoolers based on dilution refrigeration and adiabatic demagnetization refrigeration (ADR) cycles were designed, constructed, and tested. Although devices the devices did not operate as fully functional dilution cryocoolers, important information was gathered. The porous metal phase separator was demonstrated to operate in the -1-g configuration; this phase separation is the critical element in the He-3 circulation dilution cryocooler. Improvements in instrumentation needed for additional tests and development were identified.

  2. Apparatus and method for maintaining multi-component sample gas constituents in vapor phase during sample extraction and cooling

    DOEpatents

    Felix, Larry Gordon; Farthing, William Earl; Irvin, James Hodges; Snyder, Todd Robert

    2010-05-11

    A dilution apparatus for diluting a gas sample. The apparatus includes a sample gas conduit having a sample gas inlet end and a diluted sample gas outlet end, and a sample gas flow restricting orifice disposed proximate the sample gas inlet end connected with the sample gas conduit and providing fluid communication between the exterior and the interior of the sample gas conduit. A diluted sample gas conduit is provided within the sample gas conduit having a mixing end with a mixing space inlet opening disposed proximate the sample gas inlet end, thereby forming an annular space between the sample gas conduit and the diluted sample gas conduit. The mixing end of the diluted sample gas conduit is disposed at a distance from the sample gas flow restricting orifice. A dilution gas source connected with the sample gas inlet end of the sample gas conduit is provided for introducing a dilution gas into the annular space, and a filter is provided for filtering the sample gas. The apparatus is particularly suited for diluting heated sample gases containing one or more condensable components.

  3. Murphy's law of limiting dilution cloning.

    PubMed

    Staszewski, R

    1990-04-01

    Conventional practice and literature on limiting dilution cloning address the irrelevant problem of selection of a single progenitor from a uniform population, and provide optimistic estimates of monoclonality for interesting cultures and subcultures. Any cell line established via these estimates is suspect and may be polyclonally metastable. Cultures derived by limiting dilution of the progenitors of independently Poisson distributed populations obey a counterintuitive relation with the characteristics of a Murphy's law: the probability that an interesting culture is monotypic or monoclonal is less than that of a random non-sterile culture, decreases for increasingly rare interesting cultures, and is bounded below by the probability of sterility. A priori and empiric a posteriori estimates of the probability that interesting subcultures are monotypic or monoclonal are derived consistent with this principle. PMID:2362981

  4. Unstable blast shocks in dilute granular flows.

    PubMed

    Boudet, J F; Kellay, H

    2013-05-01

    Shocks and blasts can be readily obtained in granular flows be they dense or dilute. Here, by examining the propagation of a blast shock in a dilute granular flow, we show that such a front is unstable with respect to transverse variations of the density of grains. This instability has a well-defined wavelength which depends on the density of the medium and has an amplitude which grows as an exponential of the distance traveled. These features can be understood using a simple model for the shock front, including dissipation which is inherent to granular flows. While this instability bears much resemblance to that anticipated in gases, it is distinct and has special features we discuss here. PMID:23767525

  5. Inert electrode composition having agent for controlling oxide growth on electrode made therefrom

    DOEpatents

    Ray, S.P.

    1986-04-15

    An improved inert electrode composition is suitable for use as an inert electrode in the production of metals such as aluminum by the electrolytic reduction of metal oxide or metal salt dissolved in a molten salt bath. The composition comprises one or more metal alloys and metal compounds which may include oxides of the metals comprising the alloy. The alloy and metal compounds are interwoven in a network which provides improved electrical conductivity and mechanical strength while preserving the level of chemical inertness necessary for such an electrode to function satisfactorily. The electrode composition further includes a metal compound dopant which will aid in controlling the thickness of a protective oxide layer on at least the bottom portion of an electrode made therefrom during use. 12 figs.

  6. Effects of Inert Dust Clouds on the Extinction of Strained, Laminar Flames at Normal and Micro Gravity

    NASA Technical Reports Server (NTRS)

    Andac, M. Gurhan; Egolfopoulos, Fokion N.; Campbell, Charles S.; Lauvergne, Romain; Wu, Ming-Shin (Technical Monitor)

    2000-01-01

    A combined experimental and detailed numerical study was conducted on the interaction between chemically inert solid particles and strained, atmospheric methane/air and propane/air laminar flames, both premixed and non-premixed. Experimentally, the opposed jet configuration was used with the addition of a particle seeder capable of operating in conditions of varying gravity. The particle seeding system was calibrated under both normal and micro gravity and a noticeable gravitational effect was observed. Flame extinction experiments were conducted at normal gravity by seeding inert particles at various number densities and sizes into the reacting gas phase. Experimental data were taken for 20 and 37 (mu) nickel alloy and 25 and 60 (mu) aluminum oxide particles. The experiments were simulated by solving along the stagnation streamline the conservation equations of mass, momentum, energy, and species conservation for both phases, with detailed descriptions of chemical kinetics, molecular transport, and thermal radiation. The experimental data were compared with numerical simulations, and insight was provided into the effects on extinction of the fuel type, equivalence ratio, flame configuration, strain rate. particle type. particle size. particle mass, delivery rate. the orientation of particle injection with respect to the flame and gravity. It was found that for the same injected solid mass, larger particles can result in more effective flame cooling compared to smaller particles, despite the fact that equivalent masses of the larger particles have smaller total surface area to volume ratio. This counter-intuitive finding resulted from the fact that the heat exchange between the two phases is controlled by the synergistic effect of the total contact area and the temperature difference between the two phases. Results also demonstrate that meaningful scaling of interactions between the two phases may not be possible due to the complexity of the couplings between the dynamic and thermal parameters of the problem.

  7. 21 CFR 172.710 - Adjuvants for pesticide use dilutions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Adjuvants for pesticide use dilutions. 172.710... HUMAN CONSUMPTION Other Specific Usage Additives § 172.710 Adjuvants for pesticide use dilutions. The following surfactants and related adjuvants may be safely added to pesticide use dilutions by a grower...

  8. 21 CFR 172.710 - Adjuvants for pesticide use dilutions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2009-04-01 true Adjuvants for pesticide use dilutions. 172.710 Section...Additives § 172.710 Adjuvants for pesticide use dilutions. The following surfactants...related adjuvants may be safely added to pesticide use dilutions by a grower or...

  9. The ADMX Site and Dilution Refrigerator

    NASA Astrophysics Data System (ADS)

    Sloan, James; ADMX Collaboration

    2015-04-01

    The ADMX experiment searches for axions by looking for their resonant conversion to detectable photons with a frequency that directly corresponds to the axion mass (a currently unknown value). Fundamentally, the RF photon detection is relatively straightforward; the exceptional technical challenge of ADMX is achieving the sensitivity required to discern the extremely weak (~ 10-22 W) photon signal above the system noise. Greater sensitivity is achieved by either lowering the physical and amplifier noise or by integrating for longer time over a given frequency range. Noise temperatures approaching the quantum limit are achieved by operating quantum electronics, SQUIDs and JPAs, at very low physical temperatures. In the past ADMX has achieved ~1.5K physical temperatures by operating with pumped 4 He. The addition of a 3 He/4 He dilution refrigerator into ADMX will lower the physical temperatures to ~100mK, dramatically increasing the scan rate and sensitivity. I will discuss the site and hardware modifications to ADMX to accommodate the dilution refrigerator and will report on the commissioning operations of the dilution refrigerator. Supported by DOE Grants DE-FG02-97ER41029, DE-FG02-96ER40956, DE- AC52-07NA27344, DE-AC03-76SF00098, NSF Grant 1067242, and the Livermore LDRD program.

  10. Phenomenology of the simple 3-3-1 model with inert scalars

    E-print Network

    P. V. Dong; N. T. K. Ngan

    2015-12-30

    The simple 3-3-1 model that contains the minimal lepton and minimal scalar content is detailedly studied. The impact of the inert scalars, which provides dark matter candidates, on the model is discussed. All the interactions of the model are derived, and the standard model ones are identified. We make a search for the new particles including the inert ones which lead to the observed diphoton excess, rare B_s\\rightarrow \\mu^+\\mu^- decay, and B_s-\\bar{B}_s mixing as well as constraining the standard model Higgs like particle at the LHC.

  11. Three Extra Mirror or Sequential Families: Case for a Heavy Higgs Boson and Inert Doublet

    SciTech Connect

    Martinez, Homero; Melfo, Alejandra; Nesti, Fabrizio; Senjanovic, Goran

    2011-05-13

    We study the possibility of the existence of extra fermion families and an extra Higgs doublet. We find that requiring the extra Higgs doublet to be inert leaves space for three extra families, allowing for mirror fermion families and a dark matter candidate at the same time. The emerging scenario is very predictive: It consists of a standard model Higgs boson, with a mass above 400 GeV, heavy new quarks between 340 and 500 GeV, light extra neutral leptons, and an inert scalar with a mass below M{sub Z}.

  12. A steam inerting system for hydrogen disposal for the Vandenberg Shuttle

    NASA Technical Reports Server (NTRS)

    Belknap, Stuart B.

    1988-01-01

    A two-year feasibility and test program to solve the problem of unburned confined hydrogen at the Vandenberg Space Launch Complex Six (SLC-6) during Space Shuttle Main Engine (SSME) firings is discussed. A novel steam inerting design was selected for development. Available sound suppression water is superheated to flash to steam at the duct entrance. Testing, analysis, and design during 1987 showed that the steam inerting system (SIS) solves the problem and meets other flight-critical system requirements. The SIS design is complete and available for installation at SLC-6 to support shuttle or derivative vehicles.

  13. Wafer chamber having a gas curtain for extreme-UV lithography

    DOEpatents

    Kanouff, Michael P. (Livermore, CA); Ray-Chaudhuri, Avijit K. (Livermore, CA)

    2001-01-01

    An EUVL device includes a wafer chamber that is separated from the upstream optics by a barrier having an aperture that is permeable to the inert gas. Maintaining an inert gas curtain in the proximity of a wafer positioned in a chamber of an extreme ultraviolet lithography device can effectively prevent contaminants from reaching the optics in an extreme ultraviolet photolithography device even though solid window filters are not employed between the source of reflected radiation, e.g., the camera, and the wafer. The inert gas removes the contaminants by entrainment.

  14. Resonant holographic measurements of laser ablation plume expansion in vacuum and argon gas backgrounds

    SciTech Connect

    Lindley, R.A.

    1993-10-01

    This thesis discusses the following on resonant holographic measurements of laser ablation plume expansion: Introduction to laser ablation; applications of laser ablation; The study of plume expansion; holographic interferometry; resonant holographic interferometry; accounting for finite laser bandwidth; The solution for doppler broadening and finite bandwidth; the main optical table; the lumonics laser spot shape; developing and reconstructing the holograms; plume expansion in RF/Plasma Environments; Determining {lambda}{sub o}; resonant refraction effects; fringe shift interpretation; shot-to-shot consistency; laser ablation in vacuum and low pressure, inert, background gas; theoretically modeling plume expansion in vacuum and low pressure, inert, background gas; and laser ablation in higher pressure, inert, background gas.

  15. Simplified preparation of TO14 and Title III air toxic standards using a Windows software package and dynamic dilution schemes

    SciTech Connect

    Cardin, D.B.; Galoustian, E.A.

    1994-12-31

    The preparation of Air Toxic standards in the laboratory can be performed using several methods. These include injection of purge and trap standards, static dilution from pure compounds, and dynamic dilution from NIST traceable standards. A software package running under Windows has been developed that makes calculating dilution parameters for even complex mixtures fast and simple. Compound parameters such are name, molecular weight, boiling point, and density are saved in a data base for later access. Gas and liquid mixtures can be easily defined and saved as an inventory item, with preparation screens that calculate appropriate transfer volumes of each analyte. These mixtures can be utilized by both the static and dynamic dilution analysis windows to calculate proper flow rates and injection volumes for obtaining requested concentrations. A particularly useful approach for making accurate polar VOC standards will be presented.

  16. The Tungsten Inert GAS (TIG) Process of Welding Aluminium in Microgravity: Technical and Economic Considerations

    NASA Astrophysics Data System (ADS)

    Ferretti, S.; Amadori, K.; Boccalatte, A.; Alessandrini, M.; Freddi, A.; Persiani, F.; Poli, G.

    2002-01-01

    The UNIBO team composed of students and professors of the University of Bologna along with technicians and engineers from Alenia Space Division and Siad Italargon Division, took part in the 3rd Student Parabolic Flight Campaign of the European Space Agency in 2000. It won the student competition and went on to take part in the Professional Parabolic Flight Campaign of May 2001. The experiment focused on "dendritic growth in aluminium alloy weldings", and investigated topics related to the welding process of aluminium in microgravity. The purpose of the research is to optimise the process and to define the areas of interest that could be improved by new conceptual designs. The team performed accurate tests in microgravity to determine which phenomena have the greatest impact on the quality of the weldings with respect to penetration, surface roughness and the microstructures that are formed during the solidification. Various parameters were considered in the economic-technical optimisation, such as the type of electrode and its tip angle. Ground and space tests have determined the optimum chemical composition of the electrodes to offer longest life while maintaining the shape of the point. Additionally, the power consumption has been optimised; this offers opportunities for promoting the product to the customer as well as being environmentally friendly. Tests performed on the Al-Li alloys showed a significant influence of some physical phenomena such as the Marangoni effect and thermal diffusion; predictions have been made on the basis of observations of the thermal flux seen in the stereophotos. Space transportation today is a key element in the construction of space stations and future planetary bases, because the volumes available for launch to space are directly related to the payload capacity of rockets or the Space Shuttle. The research performed gives engineers the opportunity to consider completely new concepts for designing structures for space applications. In fact, once the optimised parameters are defined for welding in space, it could be possible to weld different parts directly in orbit to obtain much larger sizes and volumes, for example for space tourism habitation modules. The second relevant aspect is technology transfer obtained by the optimisation of the TIG process on aluminium which is often used in the automotive industry as well as in mass production markets.

  17. Welding of 316L Austenitic Stainless Steel with Activated Tungsten Inert Gas Process

    NASA Astrophysics Data System (ADS)

    Ahmadi, E.; Ebrahimi, A. R.

    2015-02-01

    The use of activating flux in TIG welding process is one of the most notable techniques which are developed recently. This technique, known as A-TIG welding, increases the penetration depth and improves the productivity of the TIG welding. In the present study, four oxide fluxes (SiO2, TiO2, Cr2O3, and CaO) were used to investigate the effect of activating flux on the depth/width ratio and mechanical property of 316L austenitic stainless steel. The effect of coating density of activating flux on the weld pool shape and oxygen content in the weld after the welding process was studied systematically. Experimental results indicated that the maximum depth/width ratio of stainless steel activated TIG weld was obtained when the coating density was 2.6, 1.3, 2, and 7.8 mg/cm2 for SiO2, TiO2, Cr2O3, and CaO, respectively. The certain range of oxygen content dissolved in the weld, led to a significant increase in the penetration capability of TIG welds. TIG welding with active fluxes can increase the delta-ferrite content and improves the mechanical strength of the welded joint.

  18. Reception and study of lunar surface material in inert gas medium. [considering laboratory vacuum receiving chamber

    NASA Technical Reports Server (NTRS)

    Surkov, Y. A.; Rudnitskiy, Y. M.; Glotov, V. A.

    1974-01-01

    The reception and study of lunar material returned by the Luna 16 space station is described. The layout of a vacuum receiving chamber for working with material in a helium atmosphere is examined along with the main operations involved in extracting the material from the ampule and drill.

  19. Non-invasive assessment of ventilation maldistribution in lung disease using multiple breath inert gas washouts. 

    E-print Network

    Horsley, Alex

    2009-01-01

    Clinical research in cystic fibrosis (CF) requires study endpoints that are sensitive to airways disease, repeatable and non-invasive. Despite significant advances in the treatment of CF, lung function assessments continue ...

  20. Thorium exposure during tungsten inert gas welding with thoriated tungsten electrodes.

    PubMed

    Gäfvert, T; Pagels, J; Holm, E

    2003-01-01

    The exposure to 232Th from TIG welding with thoriated electrodes has been determined at five different workshops. Welding with both alternating and direct current was investigated. The exposure levels of 232Th were generally below 10 mBq m(-3) in the breathing zone of the welders. Two samples from AC welding showed significant higher exposure levels, probably due to maladjustment of the TIG welding power source. Samples of the respirable fraction of 232Th from grinding thoriated electrodes were also collected showing exposure levels of 5 mBq m(-3) or lower. A dose estimate has been made for two scenarios, one realistic and one with conservative assumptions, showing that the annual committed effective dose from inhalation of 232Th, 230Th, 228Th and 228Ra, for a full-time TIG welder, in the realistic case is below 0.3 mSv and with conservative assumptions around 1 mSv or lower. The contribution from grinding electrodes was lower, 10 microSv or lower in the realistic case and 63 microSv or lower based on conservative assumptions. The study does not exclude occurrence of higher exposure levels under welding conditions different from those prevailing in this study. PMID:12797558