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

    , in which the inert gas agents, mostly including nitrogen, carbon dioxide, and argon, are of interest, because they are not only non-ozone-depleting but also non-toxic and non-pyrolytic gases. 1.2 Objectives In this research, nitrogen dilution effect... with additional nitrogen using CAFT modeling?????...125 6.7 Methane LFL with additional carbon dioxide using CAFT modeling???...127 6.8 Propylene LFL with additional carbon dioxide using CAFT modeling???.128 6.9 Methane and propane LFL with additional nitrogen...

  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.

    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.

  6. Enhanced-recovery inert gas processes compared

    Microsoft Academic Search

    1978-01-01

    The rising value of natural gas has caused producers to consider inert gas substitutes for gas injection projects. Three processes are currently in use for inert gas generation: boiler flue gas, gas engine exhaust, and nitrogen from cryogenic air separation. In choosing between combustion-based inert gas and cryogenic nitrogen, 3 important factors need to be considered, in addition to cost:

  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, 2011 CFR

    2011-07-01

    ...used. (h) An inerting system must: (1) Supply sufficient...throughout the vapor collection system is maintained below 8.0 percent...produce the inert gas, have a hydraulic seal and non-return valve...line. (i) An enriching system must: (1) Supply...

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

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...used. (h) An inerting system must: (1) Supply sufficient...throughout the vapor collection system is maintained below 8.0 percent...produce the inert gas, have a hydraulic seal and non-return valve...line. (i) An enriching system must: (1) Supply...

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

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...used. (h) An inerting system must: (1) Supply sufficient...throughout the vapor collection system is maintained below 8.0 percent...produce the inert gas, have a hydraulic seal and non-return valve...line. (i) An enriching system must: (1) Supply...

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

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...used. (h) An inerting system must: (1) Supply sufficient...throughout the vapor collection system is maintained below 8.0 percent...produce the inert gas, have a hydraulic seal and non-return valve...line. (i) An enriching system must: (1) Supply...

  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. 46 CFR 147.66 - Inert gas fire extinguishing systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...extinguishing systems. (a) Inert gas cylinders forming part of...209(b). (b) An inert gas cylinder must be removed from...connections between cylinders and discharge piping for fixed inert gas fire extinguishing systems...

  14. 46 CFR 147.66 - Inert gas fire extinguishing systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...extinguishing systems. (a) Inert gas cylinders forming part of...209(b). (b) An inert gas cylinder must be removed from...connections between cylinders and discharge piping for fixed inert gas fire extinguishing systems...

  15. 46 CFR 147.66 - Inert gas fire extinguishing systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...extinguishing systems. (a) Inert gas cylinders forming part of...209(b). (b) An inert gas cylinder must be removed from...connections between cylinders and discharge piping for fixed inert gas fire extinguishing systems...

  16. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...gas generators. The inert gas generator must: (a) Produce an inert gas containing less than 5% oxygen...device to continuously sample the discharge of the generator for oxygen...station that alarms when the inert gas contains 5% or more...

  17. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...gas generators. The inert gas generator must: (a) Produce an inert gas containing less than 5% oxygen...device to continuously sample the discharge of the generator for oxygen...station that alarms when the inert gas contains 5% or more...

  18. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...gas generators. The inert gas generator must: (a) Produce an inert gas containing less than 5% oxygen...device to continuously sample the discharge of the generator for oxygen...station that alarms when the inert gas contains 5% or more...

  19. 46 CFR 154.903 - Inert gas systems: General.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Inert gas systems: General. 154.903 Section...SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment...Containment Systems § 154.903 Inert gas systems: General. (a)...

  20. 46 CFR 154.903 - Inert gas systems: General.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Inert gas systems: General. 154.903 Section...SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment...Containment Systems § 154.903 Inert gas systems: General. (a)...

  1. 46 CFR 154.903 - Inert gas systems: General.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Inert gas systems: General. 154.903 Section...SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment...Containment Systems § 154.903 Inert gas systems: General. (a)...

  2. 46 CFR 154.903 - Inert gas systems: General.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Inert gas systems: General. 154.903 Section...SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment...Containment Systems § 154.903 Inert gas systems: General. (a)...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 46 CFR 154.904 - Inert gas system: Controls.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...valve in the cargo area to prevent the back...vapor into the inert gas system, or another...b) If the inert gas system is in the...outside the cargo area, a second check valve in the cargo area meeting paragraph...Automatic and manual inert gas pressure...

  8. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Inert gas generators. 154.906 Section 154...SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment...Containment Systems § 154.906 Inert gas generators. The inert gas...

  9. 46 CFR 154.904 - Inert gas system: Controls.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Inert gas system: Controls. 154.904 Section...SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment...Containment Systems § 154.904 Inert gas system: Controls. The inert gas...

  10. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Inert gas generators. 154.906 Section 154...SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment...Containment Systems § 154.906 Inert gas generators. The inert gas...

  11. 46 CFR 154.904 - Inert gas system: Controls.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Inert gas system: Controls. 154.904 Section...SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment...Containment Systems § 154.904 Inert gas system: Controls. The inert gas...

  12. Positron-inert gas differential elastic scattering

    NASA Technical Reports Server (NTRS)

    Kauppila, W. E.; Smith, Steven J.; Kwan, C. K.; Stein, T. S.

    1990-01-01

    Measurements are being made in a crossed beam experiment of the relative elastic differential cross section (DCS) for 5 to 300 eV positrons scattering from inert gas atoms (He, Ne, Ar, Kr, and Xe) in the angular range from 30 to 134 deg. Results obtained at energies around the positronium (Ps) formation threshold provide evidence that Ps formation and possibly other inelastic channels have an effect on the elastic scattering channel.

  13. 46 CFR 153.501 - Requirement for dry inert gas.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 2010-10-01 false Requirement for dry inert gas. 153.501 Section 153.501 Shipping COAST...DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment...

  14. 46 CFR 153.501 - Requirement for dry inert gas.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 2011-10-01 false Requirement for dry inert gas. 153.501 Section 153.501 Shipping COAST...DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment...

  15. 46 CFR 153.500 - Inert gas systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 5 2011-10-01 2011-10-01 false Inert gas systems. 153.500 Section 153.500 Shipping...DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment...

  16. 46 CFR 153.501 - Requirement for dry inert gas.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 2012-10-01 false Requirement for dry inert gas. 153.501 Section 153.501 Shipping COAST...DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment...

  17. 46 CFR 153.500 - Inert gas systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 5 2012-10-01 2012-10-01 false Inert gas systems. 153.500 Section 153.500 Shipping...DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment...

  18. 46 CFR 153.500 - Inert gas systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 5 2010-10-01 2010-10-01 false Inert gas systems. 153.500 Section 153.500 Shipping...DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment...

  19. 46 CFR 153.500 - Inert gas systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 5 2013-10-01 2013-10-01 false Inert gas systems. 153.500 Section 153.500 Shipping...DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment...

  20. 46 CFR 153.500 - Inert gas systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 5 2014-10-01 2014-10-01 false Inert gas systems. 153.500 Section 153.500 Shipping...DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment...

  1. Inert Gas Generation Utilizing Diesel Exhaust

    SciTech Connect

    Osgerby, I. T.; Durilla, M.

    1981-01-01

    The generation of inert gas from 60 KW diesel engine exhaust by catalytic reduction of O{sub 2} and NO{sub x} has been demonstrated. Measured O{sub 2} levels were < 10 V{sub ppm} and NO{sub x} levels were {approx} 0.1 V{sub ppm} over a wide range of equivalence ratios. Durability of the catalytic converter was demonstrated up to 200 hours operating time at two diesel engine load conditions. Effective catalyst operating range was stoichiometric to rich fuel/air ratios. Optimum operation is at stoichiometric fuel/air ratios to minimize CO emissions. Alternative converter designs are proposed to allow operation over the full diesel engine load range with essentially zero emissions of O{sub 2}, NO{sub x} and CO.

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

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...b) of this section, an inert gas generator must be located in...space that is not in the cargo area and does not have direct access...control space. (b) An inert gas generator that does not use...equipment may be located in the cargo area if specially approved by...

  3. 46 CFR 153.462 - Static discharges from inert gas systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 false Static discharges from inert gas systems. 153.462 Section...LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design...Cargoes § 153.462 Static discharges from inert gas systems. An inert...

  4. Hyperpolarized and Inert Gas MRI: The Future.

    PubMed

    Couch, Marcus J; Blasiak, Barbara; Tomanek, Boguslaw; Ouriadov, Alexei V; Fox, Matthew S; Dowhos, Krista M; Albert, Mitchell S

    2015-04-01

    Magnetic resonance imaging (MRI) is a potentially ideal imaging modality for noninvasive, nonionizing, and longitudinal assessment of disease. Hyperpolarized (HP) agents have been developed in the past 20 years for MR imaging, and they have the potential to vastly improve MRI sensitivity for the diagnosis and management of various diseases. The polarization of nuclear magnetic resonance (NMR)-sensitive nuclei other than (1)H (e.g., (3)He, (129)Xe) can be enhanced by a factor of up to 100,000 times above thermal equilibrium levels, which enables direct detection of the HP agent with no background signal. In this review, a number of HP media applications in MR imaging are discussed, including HP (3)He and (129)Xe lung imaging, HP (129)Xe brain imaging, and HP (129)Xe biosensors. Inert fluorinated gas MRI, which is a new lung imaging technique that does not require hyperpolarization, is also briefly discussed. This technique will likely be an important future direction for the HP gas lung imaging community. PMID:25228404

  5. 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...

  6. 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.

  7. 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.

  8. UV emission from excited inert-gas molecules

    Microsoft Academic Search

    Gennadii N Gerasimov; B E Krylov; A V Loginov; S A Shchukin

    1992-01-01

    Continuous vacuum ultraviolet (VUV) spectra of diatomic inert-gas molecules are ideal objects of investigation when solving many fundamental and applied problems. Problems in plasma physics, molecular spectroscopy, development of sources of VUV radiation, and formation of inverted media in gas lasers (including those in the VUV range) are some of the principal ones. This review covering the last two decades

  9. Heaterless ignition of inert gas ion thruster hollow cathodes

    NASA Technical Reports Server (NTRS)

    Schatz, M. F.

    1985-01-01

    Heaterless inert gas ion thruster hollow cathodes were investigated with the aim of reducing ion thruster complexity and increasing ion thruster reliability. Cathodes heated by glow discharges are evaluated for power requirements, flowrate requirements, and life limiting mechanisms. An accelerated cyclic life test is presented.

  10. Inert fluorinated gas MRI: a new pulmonary imaging modality.

    PubMed

    Couch, Marcus J; Ball, Iain K; Li, Tao; Fox, Matthew S; Ouriadov, Alexei V; Biman, Birubi; Albert, Mitchell S

    2014-12-01

    Fluorine-19 ((19)F) MRI of the lungs using inhaled inert fluorinated gases can potentially provide high quality images of the lungs that are similar in quality to those from hyperpolarized (HP) noble gas MRI. Inert fluorinated gases have the advantages of being nontoxic, abundant, and inexpensive compared with HP gases. Due to the high gyromagnetic ratio of (19)F, there is sufficient thermally polarized signal for imaging, and averaging within a single breath-hold is possible due to short longitudinal relaxation times. Therefore, the gases do not need to be hyperpolarized prior to their use in MRI. This eliminates the need for an expensive polarizer and expensive isotopes. Inert fluorinated gas MRI of the lungs has been previously demonstrated in animals, and more recently in healthy volunteers and patients with lung diseases. The ongoing improvements in image quality demonstrate the potential of (19)F MRI for visualizing the distribution of ventilation in human lungs and detecting functional biomarkers. In this brief review, the development of inert fluorinated gas MRI, current progress, and future prospects are discussed. The current state of HP noble gas MRI is also briefly discussed in order to provide context to the development of this new imaging modality. Overall, this may be a viable clinical imaging modality that can provide useful information for the diagnosis and management of chronic respiratory diseases. PMID:25066661

  11. Inert gas accumulation in sonoluminescing bubbles

    Microsoft Academic Search

    Detlef Lohse; Sascha Hilgenfeldt

    1997-01-01

    In this paper we elaborate on the idea [Lohse et al., Phys. Rev. Lett. 78, 1359-1362 (1997)] that (single) sonoluminescing air bubbles rectify argon. The reason for the rectification is that nitrogen and oxygen dissociate and their reaction products dissolve in water. We give further experimental and theoretical evidence and extend the theory to other gas mixtures. We show that

  12. Lattice Dynamics of Inert Gas Monolayers

    NASA Astrophysics Data System (ADS)

    Hakim, Toufic Maurice

    Lattice dynamics of rare gas monolayers is discussed over a range of nearest-neighbor separations and temperatures. The self-consistent phonon method is used in its harmonic and cubic approximations. The floating phase, in which the atoms occupy sites of a two-dimensional triangular lattice is considered first. The quantum effects are seen to be large in neon at all temperatures, while rather insignificant in xenon at low temperatures. The phonon energies in the transverse and longitudinal modes are calculated. They are found to be more sensitive to temperature and lattice parameter than in three dimensions. Sound velocities and elastic constants are evaluated for the monolayers, as well as several dynamical quantities, zero-point energies, Debye frequencies and mean vibrational amplitudes. Thermodynamic quantities including pressure isotherms, specific heats, lattice compressibility constants and free energies are also presented. The monolayer is next pinned down by a graphite substrate to form a registered structure. In addition to the adatom-adatom interaction, the effect of the graphite surface is now included through a single particle potential, and a dispersive screening force. In this phase, owing to the lack of translational invariance, a band gap is established at the center of the Brillouin zone and the system displays no acoustic phonons. The band gaps are detected and the temperature at which they vanish, known as the floating transition temperature, is calculated for xenon and krypton. The krypton adsorbed monolayer presents a different behavior from its floating counterpart; the substrate increases its anharmonicity. The xenon monolayer, on the other hand, is seen to preserve its floating properties. The cubic theory is applied next to add the appropriate correction to the phonon spectrum, and the final energies turn out to be smaller than the ones predicted by the self -consistent harmonic approximation. The self-energy of the phonons and the dynamic structure factors result naturally from the theory.

  13. Evacuation of a Residual Oil Pipeline by Inert Gas Displacement

    Microsoft Academic Search

    S. Webb; E. Bogucz; E. Levy; M. L. Barrett; C. Snyder; C. Waters

    1987-01-01

    This paper describes an analysis developed to model the inert gas displacement process for evacuating a high-pour-point oil from a long pipeline. The governing equations were derived from the basic conservation equations for mass, momentum, and energy. The resultant computer program accounts for such effects as pipeline elevation changes, laminar and turbulent oil flow, temperature-dependent oil viscosity, and heat loss

  14. 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

  15. 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)…

  16. Closed-Loop System Removes Contaminants From Inert Gas

    NASA Technical Reports Server (NTRS)

    Sharma, Pramod K.

    1995-01-01

    Concentration of oxygen in this closed-loop system kept low by use of heated catalytic sorbent bed in cartridge. Proposed to keep concentration of water vapor low by use of predried zeolite sorbent bed in another cartridge, and to remove particles smaller than 0.1 micrometer by use of porous metal filters. In specific application, chamber is one in which semiconducting materials processed. By virtue of closed-loop operation, limited supply of inert gas adequate to provide atmosphere for industrial processing of semiconductors.

  17. A scintillation detector for measuring inert gas beta rays

    NASA Astrophysics Data System (ADS)

    Shi, Hengchang; Yu, Yunchang

    1989-10-01

    The inert gas beta ray scintillation detector, which is made of organic high polymers as the base and coated with compact fluorescence materials, is a lower energy scintillation detector. It can be used in the nuclear power plant and radioactive fields as a lower energy monitor to detect inert gas beta rays. Under the conditions of time constant 10 minutes, confidence level is 99.7 percent (3 sigma), the intensity of gamma rays 2.6 x 10(sup -7) C/kg (Co-60), and the minimum detectable concentration (MDC) of this detector for Xe-133 1.2 Bq/L. The measuring range for Xe-133 is 11.1 (similar to) 3.7 x 10(exp 4) Bq/L. After a special measure is taken, the device is able to withstand 3 x 10(exp 5) Pa gauge pressure. In the loss-of-cooolant-accident, it can prevent the radioactive gas of the detector from leaking. This detector is easier to be manufactured and decontaminated.

  18. Crystallization of silicon nanoclusters with inert gas temperature control

    NASA Astrophysics Data System (ADS)

    Zhao, Junlei; Singh, Vidyadhar; Grammatikopoulos, Panagiotis; Cassidy, Cathal; Aranishi, Kengo; Sowwan, Mukhles; Nordlund, Kai; Djurabekova, Flyura

    2015-01-01

    We analyze the fundamental process of crystallization of silicon nanoclusters by means of molecular dynamics simulations, complemented by magnetron-sputter inert gas condensation, which was used to synthesize polycrystalline silicon nanoclusters with good size control. We utilize two well-established Si interatomic potentials: the Stillinger-Weber and the Tersoff III. Both the simulations and experiments show that upon cooling down by an Ar gas thermal bath, initially liquid, free-standing Si nanocluster can grow multiple crystal nuclei, which drive their transition into polycrystalline solid nanoclusters. The simulations allow detailed analysis of the mechanism, and show that the crystallization temperature is size-dependent and that the probability of crystalline phase nucleation depends on the highest temperature the cluster reaches during the initial condensation and the cooling rate after it.

  19. 46 CFR 153.462 - Static discharges from inert gas systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 false Static discharges from inert gas systems. 153.462 Section 153.462 Shipping...DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment...

  20. 46 CFR 153.462 - Static discharges from inert gas systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 false Static discharges from inert gas systems. 153.462 Section 153.462 Shipping...DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment...

  1. 46 CFR 153.462 - Static discharges from inert gas systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Static discharges from inert gas systems. 153.462 Section 153.462 Shipping...DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment...

  2. 46 CFR 153.462 - Static discharges from inert gas systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Static discharges from inert gas systems. 153.462 Section 153.462 Shipping...DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment...

  3. 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).

  4. 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.

  5. Relationships among ventilation-perfusion distribution, multiple inert gas methodology and metabolic blood-gas tensions.

    PubMed

    Lee, A S; Patterson, R W; Kaufman, R D

    1987-12-01

    The retention equations upon which the Multiple Inert Gas Method is based are derived from basic principles using elementary algebra. It is shown that widely disparate distributions produce indistinguishable sets of retentions. The limits of resolution of perfused compartments in the VA/Q distribution obtainable by the use of the multiple inert gas method are explored mathematically, and determined to be at most shunt and two alveolar compartments ("tripartite" distribution). Every continuous distribution studied produced retentions indistinguishable from those of its unique "matching" tripartite distribution. When a distribution is minimally specified, it is unique. Any additional specification (increased resolution--more compartments) of the distribution results in the existence of an infinitude of possible distributions characterized by indistinguishable sets of retention values. No further increase in resolution results from the use of more tracers. When sets of retention values were extracted from published multiple inert gas method continuous distributions, and compared with the published "measured" retention sets, substantial differences were found. This illustrates the potential errors incurred in the practical, in vivo application of the multiple inert gas method. In preliminary studies, the tripartite distribution could be determined with at least comparable accuracy by blood-gas (oxygen, carbon dioxide) measurements. PMID:2827715

  6. Heat capacity of dilute solid solutions of diatomic molecules in the matrix of inert gases

    Microsoft Academic Search

    T. N. Antsygina; K. A. Chishko; V. A. Slusarev

    1997-01-01

    A consistent theory is developed to describe temperature and concentration dependences of the excess impurity heat capacity of solid solutions of 14N2, 15N2, and O2 molecules in the matrix of inert gases Ar and Kr. It is shown that internal strain fields together with rotational degrees of freedom of the dissolving molecule contribute significantly to the thermodynamics of solutions already

  7. THE SECRETION OF INERT GAS INTO THE SWIM-BLADDER OF FISH

    PubMed Central

    Wittenberg, Jonathan B.

    1958-01-01

    The composition of the gas mixture secreted into the swim-bladders of several species of fish has been determined in the mass spectrometer. The secreted gas differed greatly from the gas mixture breathed by the fish in the relative proportions of the chemically inert gases, argon, neon, helium, and nitrogen. Relative to nitrogen the proportion of the very soluble argon was increased and the proportions of the much less soluble neon and helium decreased. The composition of the secreted gas approaches the composition of the gas mixture dissolved in the tissue fluid. A theory of inert gas secretion is proposed. It is suggested that oxygen gas is actively secreted and evolved in the form of minute bubbles, that inert gases diffuse into these bubbles, and that the bubbles are passed into the swim-bladder carrying with them inert gases. Coupled to a preferential reabsorption of oxygen from the swim-bladder this mechanism can achieve high tensions of inert gas in the swim-bladder. The accumulation of nearly pure nitrogen in the swim-bladder of goldfish (Carassius auratus) is accomplished by the secretion of an oxygen-rich gas mixture followed by the reabsorption of oxygen. PMID:13514011

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

    NASA Technical Reports Server (NTRS)

    Rawlin, V. K.

    1982-01-01

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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Thermodynamics and transport properties of metal\\/inert-gas mixtures used for arc welding

    Microsoft Academic Search

    T. Hoffmann; G. Baldea; U. Riedel

    2009-01-01

    The knowledge of thermodynamics and transport properties of gas mixtures at high temperature is important for many industrial applications. Spark ignition, re-entry problems of space-vehicles, gas dischargers, arc welding, and circuit breakers can be mentioned as examples. This paper focuses on metal\\/inert-gas mixtures in the temperature range from 300 to 30,000K, which are important for arc welding processes. As metals

  14. 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 ductility, and the HAZ was found to be the `weakest link'. Keywords: Magnesium alloy, AZ91D, TIG welding, Hot cracking, Liquation, Fracture Introduction Magnesium alloys have high strength/weight ratio

  15. Highly sensitive solids mass spectrometer uses inert-gas ion source

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Mass spectrometer provides a recorded analysis of solid material surfaces and bulk. A beam of high-energy inert-gas ions bombards the surface atoms of a sample and converts a percentage into an ionized vapor. The mass spectrum analyzer separates the vapor ionic constituents by mass-to-charge ratio.

  16. Doped inert gas crystalline media for cryogenic lasers

    NASA Astrophysics Data System (ADS)

    Frankowski, M.; Sliwinski, Gerard; Schwentner, Nikolaus

    1999-03-01

    Emissions from charge transfer states of rare gas halide RgX molecules (XeF, KrF), alkali halide ions AX (CsF, CsCl, RbF), from vibrational states of CO and NO, and also from CO2 molecules doped into rare gas and N2 solids combine the known properties of gas phase lasers transitions with high densities of excited states attainable in the condensed phase. Cryogenic solids prepared by direct condensation of gas mixtures are grown routinely and allow for solid state laser experiments and also observation of strong luminescence bands in the VUV (B-X excimer transition of RbF at 136 nm), UV (B-X transition of CsF and CsCl at 196 and 210 nm; CsF(C-A) at 211 nm; XeF(D-X) at 269; 286 and 301 nm in Ne, Ar and Kr hosts, respectively), visible (XeF(B-X) and (C-A) at 411;541 nm) and infrared wavelength region (4.96; 5.4 and 16 micrometers bands of CO, NO and CO2).

  17. Comments on ``Behaviour of inert gas bubbles under chemical concentration gradients'' by G.P. Tiwari

    NASA Astrophysics Data System (ADS)

    Evans, J. H.; van Veen, A.

    1998-01-01

    The motion of inert gas bubbles induced by thermal vacancy gradients has previously been used by the present authors to understand gas bubble release in UO 2 and metals. This approach has been recently questioned by Tiwari. In the present letter, a critical discussion of his viewpoint is presented, together with an analysis of the important experimental results of Marachov et al. There appears to be good evidence for the disputed effect.

  18. 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.

  19. 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.

  20. Can pyrophoric materials form in oil tankers with inert gas fire protection systems. Final report

    Microsoft Academic Search

    Affens

    1977-01-01

    A literature study and analysis was made concerning the potential hazard of pyrophoric ignition of flammable vapors in oil tankers with inert gas systems (IGS). Only two pyrophor possibilities seem to be likely: Formation of ferrous sulfide (FeS) and\\/or ferrous oxide (FeO). Both FeS and FeO may be formed in an oxygen limited atmosphere, such as would be the case

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

    SciTech Connect

    Jolley-Souders, K.; Geib, R. [Matheson Gas Products, Montgomeryville, PA (United States); Dunn, C. [Environics, Inc., Tolland, CT (United States)

    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.

  2. 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

  3. 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.

  4. Dilute bose gas in a quasi-two dimensional trap

    Microsoft Academic Search

    Brandon Peter van Zyl; Rajat Kumar Bhaduri; Justin Sigetich

    2002-01-01

    We investigate the behavior of a dilute quasi two-dimensional, harmonically confined, weakly interacting Bose gas within the finite-temperature Thomas-Fermi approximation. We find that the thermodynamic properties of the system are markedly different for repulsive and attractive interactions. Specifically, in contrast to the repulsive case, there appears to be a phase transition when the atoms interact with an attractive pseudo-potential, in

  5. Dilute Bose gas in a quasi-two-dimensional trap

    Microsoft Academic Search

    Brandon P. van Zyl; R. K. Bhaduri; Justin Sigetich

    2002-01-01

    We investigate the behaviour of a dilute quasi-two-dimensional, harmonically confined, weakly interacting Bose gas within the finite-temperature Thomas-Fermi approximation. We find that the thermodynamic properties of the system are markedly different for repulsive and attractive interactions. Specifically, in contrast to the repulsive case, there appears to be a phase transition when the atoms interact with an attractive pseudo-potential, in the

  6. 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.

  7. Effect of the Inert Gas Adsorption on the Bilayer Graphene to the Localized Electron Magnetotransport

    NASA Astrophysics Data System (ADS)

    Fukuda, A.; Terasawa, D.; Ohno, Y.; Matsumoto, K.

    2014-12-01

    Graphene has a fascinating property that the two-dimensional electron gas is easily accessible externally and it is challenging to investigate the effects of the adsorption of inert gases on graphene, which may be the least effective chemically and physically. We carry out the magnetotransport measurements of 4He-adsorbed bilayer graphene at low temperatures and the magnetic field B ranging from 0 to 4 T. The magnetoresistance ?Rxx change from the pristine graphene is measured as a function of gate voltage Vg and B for partial coverage of 1/10 (= 0.1) layers and one layer 4He-adsorbed graphene. The overall magnitudes of ?Rxx for one layer are larger than the one for 1/10 layers. Signs of ?Rxx depend on the Vg for the entire range of B, associated with the magnetoresistance oscillation owing to the weak localization in the pristine graphene.

  8. 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

  9. Electroluminescence of monodispersed silicon nanocrystallites synthesized by pulsed laser ablation in inert background gas

    NASA Astrophysics Data System (ADS)

    Makino, Toshiharu; Yamada, Yuka; Suzuki, Nobuyasu; Yoshida, Takehito; Onari, Seinosuke

    2002-09-01

    We have characterized dc-excited light-emitting properties of monodispersed silicon (Si) nanocrystallites (nc-Si) synthesized by pulsed laser ablation in inert background gas. In a case where the monodispersed nc-Si were passivated by an indium oxide (In 2O 3) layer without breaking the vacuum, the electroluminescence (EL) spectrum had a narrow bandwidth of 0.15 eV peaked at slightly higher energy region (1.17 eV) than the bulk Si energy gap (1.11 eV), at room temperature. On the other hand, broad visible EL (peak: 1.7 eV, bandwidth: 0.46 eV) appeared when the monodispersed nc-Si were exposed to air before In 2O 3 passivation. These light-emitting mechanisms are discussed in relation to quantum confinement effects and oxide-related emission centers.

  10. 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.

  11. Process parameter selection for optimizing the weld pool geometry in the tungsten inert gas welding of stainless steel

    Microsoft Academic Search

    S. C Juang; Y. S Tarng

    2002-01-01

    In this paper, the selection of process parameters for obtaining an optimal weld pool geometry in the tungsten inert gas (TIG) welding of stainless steel is presented. Basically, the geometry of the weld pool has several quality characteristics, for example, the front height, front width, back height and back width of the weld pool. To consider these quality characteristics together

  12. Characterization of uranium carbide microspheres in an inert zirconium carbide matrix for gas fast reactors

    NASA Astrophysics Data System (ADS)

    Geathers, Jerome J.

    The characterization of an advanced nuclear fuel for Gas Fast reactors has been studied. Portions of a dispersion/composite fuel involving Uranium Carbide (UC) and Zirconium Carbide (ZrC) have been characterized and studied. Uranium carbide (UC) microspheres produced in the USC-Nuclear Materials Laboratory were subjected to metallographic techniques, and then characterized by analytical methods. A method for separation of spherical and non-spherical microspheres was developed involving an inclined plane. Metallography was done using the LECO SS-1000 grinder/polisher system. Quantitative analysis and imagery were gathered using scanning electron microscopy (SEM), back scattering electron microscopy (BSE), electron microprobe for quantitative analysis (EPMA), and x-ray photoelectron spectroscopy (XPS). X-ray diffraction (XRD) was also used to find the crystal structure of the microspheres. The UC microspheres were further investigated by annealing. The annealing process was completed using a CM Furnace in an inert argon gas. The results of the experiment were analyzed using the same methods mentioned above. Uranium diffusion was found in the ZrC matrix and was confirmed to be possible through diffusion calculations.

  13. Deposition of Size-Selected Cu Nanoparticles by Inert Gas Condensation

    PubMed Central

    2010-01-01

    Nanometer size-selected Cu clusters in the size range of 1–5 nm have been produced by a plasma-gas-condensation-type cluster deposition apparatus, which combines a grow-discharge sputtering with an inert gas condensation technique. With this method, by controlling the experimental conditions, it was possible to produce nanoparticles with a strict control in size. The structure and size of Cu nanoparticles were determined by mass spectroscopy and confirmed by atomic force microscopy (AFM) and scanning electron transmission microscopy (STEM) measurements. In order to preserve the structural and morphological properties, the energy of cluster impact was controlled; the energy of acceleration of the nanoparticles was in near values at 0.1 ev/atom for being in soft landing regime. From SEM measurements developed in STEM-HAADF mode, we found that nanoparticles are near sized to those values fixed experimentally also confirmed by AFM observations. The results are relevant, since it demonstrates that proper optimization of operation conditions can lead to desired cluster sizes as well as desired cluster size distributions. It was also demonstrated the efficiency of the method to obtain size-selected Cu clusters films, as a random stacking of nanometer-size crystallites assembly. The deposition of size-selected metal clusters represents a novel method of preparing Cu nanostructures, with high potential in optical and catalytic applications. PMID:20652132

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

    NASA Technical Reports Server (NTRS)

    Verhey, Timothy R.; Macrae, Gregory S.

    1990-01-01

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

  15. Modeling In-Flight Inert Gas Distribution in a 747 Center Wing Fuel Tank

    Microsoft Academic Search

    William M. Cavage; Timothy Bowman

    Extensive development and analysis has illustrated that fuel tank inerting, using air separation modules, is a reasonably cost-effective approach to preventing fuel tank explosions. To support the development of the Federal Aviation Administration inerting system, analytical and scale replica models of a Boeing 747 center wing fuel tank were developed and used to gage the ability of these relatively simple

  16. 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.

  17. 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.

  18. 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

  19. Effect of inert cover gas on performance of radioisotope Stirling space power system

    NASA Astrophysics Data System (ADS)

    Carpenter, R.; Kumar, V.; Or, C.; Schock, A.

    2001-02-01

    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 on missions 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. 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.

  1. 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.)

  2. Soret and Dilution Effects on Premixed Flames

    Microsoft Academic Search

    PEDRO GARCÍA-YBARRA; COLETTE NICOLI; PAUL CLAVIN

    1984-01-01

    The structure of a wrinkled premixed flame is analysed theoretically. By assuming the reactive mixture diluted in an inert gas and a weak cross-diffusion coupling between the heat and mass fluxes, the effect of the change by the reaction of the physical gas properties (thermal conductivity, specific heat, number of molecules) and Soret and Dufour diffusions have been investigated in

  3. A comparative evaluation of electrical velocimetry and inert gas rebreathing for the non-invasive assessment of cardiac output

    Microsoft Academic Search

    Frederik Trinkmann; Manuel Berger; Ursula Hoffmann; Martin Borggrefe; Jens J. Kaden; Joachim Saur

    Background  When assessing the function of the cardiovascular system, cardiac output (CO) is a substantial parameter. For its determination,\\u000a numerous non-invasive techniques have been proposed in the recent years including inert gas rebreathing (IGR) and impedance\\u000a cardiography (ICG). The aim of our study was to evaluate whether a novel ICG algorithm (electrical velocimetry) and IGR can\\u000a be used interchangeably in the

  4. 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.

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

    SciTech Connect

    Miyakawa, Masashi; Toda, Yoshitake; Hayashi, Katsuro; Hirano, Masahiro; Kamiya, Toshio; Matsunami, Noriaki; Hosono, Hideo [Frontier Collaborative Research Center, P.O. Box S2-13, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Hosono Transparent Electro-Active Materials, Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Agency, KSP C-1232, 3-2-1 Sakado, Takatsu-ku, Kawasaki 213-0012 (Japan); Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Center for Integrated Research in Science and Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Frontier Collaborative Research Center and Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan)

    2005-01-15

    Inert gas ion implantation (acceleration voltage 300 kV) into polycrystalline 12CaO{center_dot}7Al{sub 2}O{sub 3} (C12A7) films was investigated with fluences from 1x10{sup 16} to 1x10{sup 17} cm{sup -2} at elevated temperatures. Upon hot implantation at 600 deg. C with fluences greater than 1x10{sup 17} cm{sup -2}, the obtained films were colored and exhibited high electrical conductivity in the as-implanted state. The extrusion of O{sup 2-} ions encaged in the crystallographic cages of C12A7 crystal, which leaves electrons in the cages at concentrations up to {approx}1.4x10{sup 21} cm{sup -3}, may cause the high electrical conductivity. On the other hand, when the fluence is less than 1x10{sup 17} cm{sup -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{sup +}-like centers. The electrons forming the F{sup +}-like centers are photo released from the encaged H{sup -} ions, which are presumably derived from the preexisting OH{sup -} 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{sup -} ion in the films. The hot ion implantation technique provides a nonchemical process for preparing electronic conductive C12A7 films.

  6. 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

  7. 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.

  8. Noninvasive cardiac output measurement by inert gas rebreathing in suspected pulmonary hypertension.

    PubMed

    Farina, Stefania; Teruzzi, Giovanni; Cattadori, Gaia; Ferrari, Cristina; De Martini, Stefano; Bussotti, Maurizio; Calligaris, Giuseppe; Bartorelli, Antonio; Agostoni, Piergiuseppe

    2014-02-01

    The objective of this study was to evaluate inert gas rebreathing (IGR) reliability in cardiac output (CO) measurement compared with Fick method and thermodilution. IGR is a noninvasive method for CO measurement; CO by IGR is calculated as pulmonary blood flow plus intrapulmonary shunt. IGR may be ideal for follow-up of patients with pulmonary hypertension (PH), sparing the need of repeated invasive right-sided cardiac catheterization. Right-sided cardiac catheterization with CO measurement by thermodilution, Fick method, and IGR was performed in 125 patients with possible PH by echocardiography. Patients were grouped according to right-sided cardiac catheterization-measured mean pulmonary and wedge pressures: normal pulmonary arterial pressure (n = 20, mean pulmonary arterial pressure = 18 ± 3 mm Hg, pulmonary capillary wedge pressure = 11 ± 5 mm Hg), PH and normal pulmonary capillary wedge pressure (PH-NW, n = 37 mean pulmonary arterial pressure = 42 ± 13 mm Hg, pulmonary capillary wedge pressure = 11 ± 6 mm Hg), and PH and high pulmonary capillary wedge pressure (PH-HW, n = 68, mean pulmonary arterial pressure = 37 ± 9 mm Hg, pulmonary capillary wedge pressure = 24 ± 6 mm Hg). Thermodilution and Fick measurements were comparable. Fick and IGR agreement was observed in normal pulmonary arterial pressure (CO = 4.10 ± 1.14 and 4.08 ± 0.97 L/min, respectively), whereas IGR overestimated Fick in patients with PH-NW and those with PH-HW because of intrapulmonary shunting overestimation in hypoxemic patients. When patients with arterial oxygen saturation (SO2) ?90% were excluded, IGR and Fick agreement improved in PH-NW (CO = 4.90 ± 1.70 and 4.76 ± 1.35 L/min, respectively) and PH-HW (CO = 4.05 ± 1.04 and 4.10 ± 1.17 L/min, respectively). In hypoxemic patients, we estimated pulmonary shunt as Fick - pulmonary blood flow and calculated shunt as: -0.2423 × arterial SO2 + 21.373 L/min. In conclusion, IGR is reliable for CO measurement in patients with PH with arterial SO2 >90%. For patients with arterial SO2 ?90%, a new formula for shunt calculation is proposed. PMID:24315114

  9. 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.

  10. 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.

  11. 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.

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

    SciTech Connect

    Kent, Brian R., E-mail: bkent@nrao.ed [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States)

    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.

  13. 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

  14. 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.

  15. 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 must also consider methods to control the dilution the welding of superaustenitic stainless steels.e., the individual values of Vfm and VI are not important in controlling the dilution and resultant weld

  16. 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.

  17. 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.

  18. Role of interphase interactions during gas detonation in inert porous medium

    NASA Astrophysics Data System (ADS)

    Balapanov, D. M.; Urmancheev, S. F.

    2010-07-01

    A mathematical model of detonation in a two-phase mixture consisting of a gaseous monofuel and closely packed noninflammable solid particles is proposed. The structure of detonation waves in a pure gas is compared to that in monodisperse mixtures with various diameters of particles. Two special regimes of detonation are separated, in which (i) gas is immediately inflamed due to shock compression and (ii) ignition starts at the surface of particles, upon reflection of the chock wave front. It is shown that inertial effects during the flow past particles can both increase and decrease the detonation velocities. The calculated detonation velocities well agree with experimental data.

  19. Molecular dynamics investigations of the coalescence of iron clusters embedded in an inert-gas heat bath

    SciTech Connect

    Luemmen, N.; Kraska, T. [Physical Chemistry, University of Cologne, Luxemburger Strasse 116, D-50939 Cologne (Germany)

    2005-05-15

    A detailed analysis of the coalescence of iron clusters over the course of their growth in an inert-gas atmosphere is presented. The investigation is performed by molecular dynamics simulations, using a recent version of the embedded atom method for iron. For several coalescence events extracted from realistic particle-growth simulations, the change of temperature, the atomic structure, and the morphology are analyzed. Here, the change in morphology is investigated by the relative number of atoms in the surface related to the driving force of the coalescence, the surface energy. The duration of the coalescence depends on the state of the colliding clusters, which is related to their temperature. At elevated temperatures an exponential decay of the relaxation of the cluster shape is found in case of liquid clusters. Clusters at lower temperatures exhibit a regular atomic structure. The coalescence includes the restructuring of the clusters, leading to deviations from the exponential decay of the cluster properties. Here, a distinct three-step coalescence process has been identified for structured clusters under nonadiabatic conditions. Each of these steps is related to a different extent of heat exchange with the carrier gas.

  20. 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...

  1. Evaporation and Condensation of Large Droplets in the Presence of Inert Admixtures Containing Soluble Gas

    E-print Network

    Elperin, Tov

    effect of the greenhouse gases (Krämer et al. 2000). All these phenomena involve evaporation of droplets the mutual influence of heat and mass transfer during gas absorption and evaporation or condensation. The system of transient conjugate nonlinear energy and mass conservation equa- tions was solved using

  2. Electrical current density in a sheared dilute gas

    Microsoft Academic Search

    Concepción Mar??n; Vicente Garzó

    1999-01-01

    Electrical current density of charged particles across a rarefied gas of neutral particles under shear flow is analyzed in the limit of small electric fields. The concentration of the charged species is assumed to be much smaller than that of the neutral species so that the interactions of charged–neutral and neutral–neutral type are the dominant ones. The study is made

  3. Electrical current density in a sheared dilute gas

    Microsoft Academic Search

    Concepcion Marna; Vicente Garzo

    Electrical current density of charged particles across a rareed gas of neutral particles under shear ow is analyzed in the limit of small electric elds. The concentration of the charged species is assumed to be much smaller than that of the neutral species so that the interactions of charged{neutral and neutral{neutral type are the dominant ones. The study is made

  4. Gas turbine annular combustor with radial dilution air injection

    Microsoft Academic Search

    J. R. Shekelton; D. C. Johnson

    1991-01-01

    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

  5. Determination of Cyanide in Blood by Isotope Dilution Gas Chromatography-Mass Spectrometry

    Microsoft Academic Search

    Karen E. Murphy; Michele M. Schantz; Therese A. Butler; Bruce A. Benner; Laura J. Wood; Gregory C. Turk

    Background: Cyanide (CN) is a lethal toxin. Quantifi- cation in blood is necessary to indicate exposure from many sources, including food, combustion byproducts, and terrorist activity. We describe an automated proce- dure based on isotope-dilution gas chromatography- mass spectrometry (ID GC\\/MS) for the accurate and rapid determination of CN in whole blood. Methods: A known amount of isotopically labeled po-

  6. Effect of Reformate Components on PEMFC Performance Dilution and Reverse Water Gas Shift Reaction

    E-print Network

    Van Zee, John W.

    Effect of Reformate Components on PEMFC Performance Dilution and Reverse Water Gas Shift Reaction on the performance of proton exchange membrane fuel cells PEMFCs with Pt and Pt/Ru alloy anodes. The performance with N2 /H2 mixtures. The same deviations were observed with CO2 /H2 mixtures for a PEMFC with a Pt

  7. Momentum Distribution of a Dilute Unitary Bose Gas with Three-Body Losses

    NASA Astrophysics Data System (ADS)

    Laurent, Sébastien; Leyronas, Xavier; Chevy, Frédéric

    2014-11-01

    Using a combination of Boltzmann's equation and virial expansion, we study the effect of three-body losses and interactions on the momentum distribution of a homogeneous unitary Bose gas in the dilute limit where quantum correlations are negligible. The comparison of our results to the recent measurement made at JILA on a unitary gas of 85Rb allows us to determine an experimental fugacity z =0.5 (1 ).

  8. 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.

  9. Techniques for optimizing inerting in electron processors

    NASA Astrophysics Data System (ADS)

    Rangwalla, I. J.; Korn, D. J.; Nablo, S. V.

    1993-07-01

    The design of an "inert gas" distribution system in an electron processor must satisfy a number of requirements. The first of these is the elimination or control of beam produced ozone and NO x which can be transported from the process zone by the product into the work area. Since the tolerable levels for O 3 in occupied areas around the processor are <0.1 ppm, good control techniques are required involving either recombination of the O 3 in the beam heated process zone, or exhausting and dilution of the gas at the processor exit. The second requirement of the inerting system is to provide a suitable environment for completing efficient, free radical initiated addition polymerization. In this case, the competition between radical loss through de-excitation and that from O 2 quenching must be understood. This group has used gas chromatographic analysis of electron cured coatings to study the trade-offs of delivered dose, dose rate and O 2 concentrations in the process zone to determine the tolerable ranges of parameter excursions can be determined for production quality control purposes. These techniques are described for an ink:coating system on paperboard, where a broad range of process parameters have been studied (D, ?, O 2. It is then shown how the technique is used to optimize the use of higher purity (10-100 ppm O 2) nitrogen gas for inerting, in combination with lower purity (2-20, 000 ppm O 2) non-cryogenically produced gas, as from a membrane or pressure swing adsorption generators.

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

    SciTech Connect

    Xu Nan [College of Material Science and Engineering, Chongqing University, Chongqing 400044 (China); Shen Jun, E-mail: shenjun2626@163.com [College of Material Science and Engineering, Chongqing University, Chongqing 400044 (China); Xie Weidong; Wang Linzhi; Wang Dan; Min Dong [College of Material Science and Engineering, Chongqing University, Chongqing 400044 (China)

    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.

  11. Plasma-weld pool interaction in tungsten inert-gas configuration

    NASA Astrophysics Data System (ADS)

    Mougenot, J.; Gonzalez, J.-J.; Freton, P.; Masquère, M.

    2013-04-01

    A three-dimensional (3D) transient model of a transferred argon arc in interaction with an anode material is presented and the results discussed. The model based on a finite volume method is developed using the open software @Saturne distributed by Electricité de France. The 3D model includes the characterization of the plasma gas and of the work piece with a current continuity resolution in the whole domain. Transport and thermodynamic properties are dependent on the local temperature and on the vapours emitted by the eroded material due to the heat flux transferred by the plasma. Drag force, Marangoni force, Laplace and gravity forces are taken into account on the weld pool description. The plasma and the weld pool characteristics are presented and compared with experimental and theoretical results from the literature. For a distance between the two electrodes of d = 5 mm and an applied current intensity of I = 200 A, the vapour concentration is weak. The influence of the parameters used in the Marangoni formulation is highlighted. Finally, in agreement with some authors, we show with this global transient 3D model that it is not necessary to include the voltage drop in the energy balance.

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

    E-print Network

    Khatiwala, Samar

    as a function of wind speed. Our results indicate air injection values at high wind speeds (> 10 m s-1-sea interface commonly is parameterized as the product of a gas transfer coefficient, k, and the air-sea concentration gradient of a gas such that, Fas=-kc([C]-cpc) or Fas=-kc([C]-[C] slp eq ) (1) where [C] (mol m3

  13. Self-association of ( R)-1,3-butanediol in an inert dilute solution studied by infrared spectroscopy in combination with density functional theory and chemometrics

    NASA Astrophysics Data System (ADS)

    Ni, Yi; Hashimoto, Chihiro; Li, Boyan; Futami, Yoshisuke; Dou, Xiaoming; Ozaki, Yukihiro

    2008-03-01

    Self-association of ( R)-1,3-butanediol in a dilute carbon tetrachloride (CCl 4) solution was studied by infrared (IR) spectroscopy in combination with density functional theory (DFT), Sugeta's nonlinear least square (NLS) method and chemometrics methods including fixed-size moving window evolving factor analysis (FSMWEFA), principal component analysis (PCA), simple-to-use interactive self-modeling mixture analysis (SIMPLISMA), and iterative target transformation factor analysis (ITTFA). The association size of ( R)-1,3-butanediol in the CCl 4 solution estimated from PCA, SIMPLISMA and ITTFA are 3.2730, 3.2797 and 3.2950, respectively, suggesting that the major multimer species of ( R)-1,3-butanediol in the solution are trimers. A theoretical investigation of trimer structures of ( R)-1,3-butanediol was carried out with DFT. It was found from the DFT calculation that cyclic trimers are more stable than linear ones. Structure of hydrogen-bonded OH ring and position of side chains are the two main factors that determine the stability of trimers. The intra-molecular hydrogen bonded OH…OH structure in the ( R)-1,3-butanediol monomer brings additional influence on the trimers' structures.

  14. CFD study of the heat transfer between a dilute gas particle suspension flow and an obstruction

    SciTech Connect

    Nguyen, A.V.; Fletcher, C.A.J. [Univ. of New South Wales, Sydney, New South Wales (Australia). Centre for Advanced Numerical Computation in Engineering and Science; Tu, J.Y. [Australian Nuclear Science and Technology Organization, Menai, New South Wales (Australia)

    1999-04-01

    The effect on heat transfer of solid particles suspended in a gas flow is of considerable importance in a number of industrial applications, ranging from coal combustion equipment and heat exchangers to catalytic reaction or cooling of nuclear reactors using gas graphite dust suspensions. Here, the heat transfer process between a dilute gas-particle suspension flow and an obstruction has been numerically investigated employing a novel Eulerian formulation for dilute gas particle suspension flows, which allows interaction of the key mechanisms to be quantified for the first time. As the particle reflection occurs around the obstruction, the heat transfer process has been modeled taking into account the incident and reflected particles explicitly. In the energy equations these particle families are treated separately. Only the effect on the gas convective heat transfer is expected to be of primary significance and investigated. The numerical computation is performed using the commercial computational fluid dynamics code, FLUENT, with the User Defined Subroutines. The authors study the heat transfer process between a dilute gas particle flow and an obstruction with simple geometries such as a 45{degree} ramp and a cylindrical tube. The theoretical results for the latter case are compared with the available experimental data. The numerical simulation shows that both the particle size and the particle concentration (in the thermal boundary layer) affect the heat transfer process. Since both the particle incidence and reflection depend on the particle size and strongly influence the particle concentration distribution, they have to be physically correctly treated in the modeling of the heat transfer, as is demonstrated in the novel formulation. There is an optimum particle size for a maximum enhancement of the heat transfer. The particle concentration increases the efficiency of the heat transfer process expressed in terms of the local Nusselt numbers.

  15. Effect of nozzle orientation on the gas dynamics of inert-gas laser cutting of mild steel

    SciTech Connect

    Brandt, A.D.; Scroggs, S.D.; Settles, G.S. [Penn State Univ., University Park, PA (United States)

    1996-12-31

    This investigation applies sonic and supersonic coaxial and off-axis nozzles to the cutting of mild steel sheet of 1 to 4 mm thickness. A 1 kW CW CO{sub 2} laser is used with nitrogen as the assist gas. Sonic coaxial cutting is compared to that of off-axis nozzles which vary in orientation from 20-60{degrees} behind the laser axis, and in exit Mach number from 1 to 2.4. Results show a 50% increase in maximum cutting speed at about a 40{degrees} nozzle angle. In comparison, variations in nozzle exit Mach number have little effect. A scale-model kerf was used to visualize the kerf gas dynamics, revealing that nozzle angles of 0-20{degrees} cause a shock wave/boundary layer interaction with flow separation inside the kerf. Angles of 20-45{degrees} alleviate this interaction, producing a uniform supersonic flow throughout the kerf which yields high cutting speeds due to high shear forces. For nozzle angles greater than 45{degrees} the assist gas is diverted away from the kerf, reducing cutting speed. Compared to nozzle angle, exit Mach number was found to be of secondary importance.

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

    NASA Astrophysics Data System (ADS)

    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 xtilde 0.001 . The condensate fraction in 2D is also computed and found generally lower than the 3D one at the same x .

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

    SciTech Connect

    Mazzanti, F. [Departament d'Electronica, Enginyeria i Arquitectura La Salle, Pg. Bonanova 8, Universitat Ramon Llull, E-08022 Barcelona (Spain); Polls, A. [Department d'Estructura i Constituents de la Materia, Diagonal 645, Universitat de Barcelona, E-08028 Barcelona (Spain); Fabrocini, A. [Dipartimento di Fisica 'E. Fermi', Universita di Pisa, and INFN, Sezione di Pisa, Via Buonarroti, 2 I-56100 Pisa (Italy)

    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.

  18. Ground-Based Inerting of Commercial Transport Aircraft Fuel Tanks

    Microsoft Academic Search

    William M. Cavage

    Extensive research has been performed by the Federal Aviation Administration to help develop practical and cost-effective inerting systems for commercial transport airplane fuel tanks. The concept of ground-based inerting has been studied in the laboratory and on two different aircraft in an attempt to develop a cost- effective methodology for fuel tank inerting. These research projects studied inert gas requirements,

  19. Coupled-cluster theory of a gas of strongly-interacting electrons in the dilute limit

    SciTech Connect

    Mihaila, Bodgan [Los Alamos National Laboratory; Cardenas, Andres L [Los Alamos National Laboratory

    2008-01-01

    We study the ground-state properties of a dilute gas of strongly-interacting fermions in the framework of the coupled-cluster expansion (CCE). We demonstrate that properties such as universality, opening of a gap in the excitation spectrum and applicability of s-wave approximations appear naturally in the CCE approach. In the zero-density limit, we show that the ground-state energy density depends on only one parameter which in turn may depend at most on the spatial dimensionality of the system.

  20. Fluid-dynamical and poro-elastic coupling of gas permeability of inert and sorbing gases on an Australian sub-bituminous coal

    NASA Astrophysics Data System (ADS)

    Gensterblum, Y.; Krooss, B. M.

    2013-12-01

    The interaction and the coupling of slip-flow, a fluid dynamic phenomenon, and the cleat volume compressibility which is a poroelastic phenomenon has been investigated on two samples from the Taroom coal measure, Surat Basin, Queensland Australia. Measurements were performed using inert (helium and argon) and sorbing gases (nitrogen, methane and carbon dioxide) at controlled effective stress. We observed the following regular sequence of permeability coefficients for the different gases: Helium >> argon => nitrogen > methane >> CO2 Even after slip-flow correction, different intrinsic permeability coefficients are obtained for the same sample if different gases are used in the tests. The permeability values determined with helium are largest while those measured with CO2 are lowest. Inert gases like helium and argon show higher apparent- and even slip flow-corrected permeability coefficients than sorbing gases like methane or carbon dioxide. This observation is contrary to the prediction that the slip-flow corrected permeability have to be the same for all gases. The cleat volume compressibility cf was evaluated using the 'matchstick approach' [1, 2]. The cleat volume compressibility coefficients cf are almost identical for the two samples taken from the same well. However, for one sample a strong dependence of the cf with the mean pore pressure was observed. This is attributed to a strong slip-flow effect caused by a narrow cleat system as compared to the sister sample. The cleat volume compressibility coefficient cf is almost the same for inert and sorbing gases. We conclude that the occurrence of slip-flow in coals is able to compensate the permeability reduction resulting from increasing effective stress. This should lead to a much higher productivity of coal bed methane reservoirs in the third production phase (pseudo-steady state phase; [3]). This conclusion appears to be also valid for shale gas and tight gas reservoirs, where the gas transport takes place in meso- and micropores, as well.

  1. Effect of support on the thermal decomposition of (NH 4) 6Mo 7O 24·4H 2O in the inert gas atmosphere

    Microsoft Academic Search

    C Thomazeau; V Martin; P Afanasiev

    2000-01-01

    Thermal decomposition of bulk or supported (NH4)6Mo7O24·4H2O (AHM) in the inert gas (Ar) atmosphere was studied. Several solids, including MgO, SiO2, ZrO2, C, Nb2O5 or Al2O3, were used as supports. The AHM decomposition was monitored by the mass-spectrometric analysis of the evolved gases and thermal analysis. Solid products were characterised using X-ray diffraction (XRD), UV–Vis, X-ray photoelectron spectroscopy (XPS), and

  2. 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).

  3. Nonlinear Couette flow in a dilute gas: Comparison between theory and molecular-dynamics simulation

    NASA Astrophysics Data System (ADS)

    Montanero, J. M.; Garzó, V.

    1998-08-01

    Nonlinear transport properties of a d-dimensional dilute gas subjected to a planar Couette flow are determined. The results are obtained from a kinetic model that accounts for the correct value of the Prandtl number. The solution is characterized by constant pressure and linear velocity and parabolic temperature profiles with respect to a scaled variable. The main transport coefficients are explicitly obtained as nonlinear functions of the reduced shear rate. A comparison with recent molecular-dynamics simulations of a bidimensional gas of hard disks [D. Risso and P. Cordero, Phys. Rev. E 56, 489 (1997)] is carried out. Such a comparison shows that our results are in better agreement with the computer simulations than those previously derived from other approximations, especially in the case of the thermal conductivity tensor.

  4. 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.

  5. Defect effect on tribological behavior of diamond-like carbon films deposited with hydrogen diluted benzene gas in aqueous environment

    NASA Astrophysics Data System (ADS)

    Yi, Jin Woo; Park, Se Jun; Moon, Myoung-Woon; Lee, Kwang-Ryeol; Kim, Seock-Sam

    2009-05-01

    This study examined the friction and wear behavior of diamond-like carbon (DLC) films deposited from a radio frequency glow discharge using a hydrogen diluted benzene gas mixture. The DLC films were deposited on Si (1 0 0) and polished stainless steel substrates by radio frequency plasma-assisted chemical vapor deposition (r.f.-PACVD) at hydrogen to benzene ratios, or the hydrogen dilution ratio, ranging from 0 to 2.0. The wear test was carried out in both ambient and aqueous environments using a homemade ball-on-disk type wear rig. The stability of the DLC coating in an aqueous environment was improved by diluting the benzene precursor gas with hydrogen, suggesting that hydrogen dilution during the deposition of DLC films suppressed the initiation of defects in the film and improved the adhesion of the coating to the interface.

  6. Correlation of leak rates of various fluids with the leak rate of an inert gas in the same configuration

    NASA Technical Reports Server (NTRS)

    Schleier, Howard

    1990-01-01

    NASA is interested in field testing for possible leakage in their fueling systems; however, many fuels are hazardous to the extent that personnel cannot be on hand when the system is being monitored. It is proposed that an inert material such as helium be used on the field test, and that those results be calibrated to simulate the actual process. A technique such as this would allow personnel to be on site during the testing and use techniques to determine the behavior of the system that could not be used otherwise. This endeavor attempts to develop such a correlation. The results show promise, but more refinement and data are needed.

  7. The evaluation of the pyrochemistry for the treatment of Gen IV nuclear fuels Inert matrix chlorination studies in the gas phase or molten chloride salts

    NASA Astrophysics Data System (ADS)

    Bourg, S.; Péron, F.; Lacquement, J.

    2007-01-01

    The structure of the fuels for the future Gen IV nuclear reactors will be totally different from those of PWR, especially for the GFR concept including a closed cycle. In these reactors, fissile materials (carbides or nitrides of actinides) should be surrounded by an inert matrix. In order to build a reprocessing process scheme, the behavior of the potential inert matrices (silicon carbide, titanium nitride, and zirconium carbide and nitride) was studied by hydro- and pyrometallurgy. This paper deals with the chlorination results at high temperature by pyrometallurgy. For the first time, the reactivity of the matrix towards chlorine gas was assessed in the gas phase. TiN, ZrN and ZrC are very reactive from 400 °C whereas it is necessary to be over 900 °C for SiC to be as fast. In molten chloride melts, the bubbling of chlorine gas is less efficient than in gas phase but it is possible to attack the matrices. Electrochemical methods were also used to dissolve the refractory materials, leading to promising results with TiN, ZrN and ZrC. The massive SiC samples used were not conductive enough to be studied and in this case specific SiC-coated carbon electrodes were used. The key point of these studies was to find a method to separate the matrix compounds from the fissile material in order to link the head to the core of the process (electrochemical separation or liquid-liquid reductive extraction in the case of a pyrochemical reprocessing).

  8. Sensing properties to dilute chlorine gas of indium oxide based thin film sensors prepared by electron beam evaporation

    Microsoft Academic Search

    Jun Tamaki; Chizuko Naruo; Yoshifumi Yamamoto; Masao Matsuoka

    2002-01-01

    Indium oxide based thin film sensors have been prepared by means of an electron beam evaporation and subjected to the detection of dilute Cl2 gas less than ppm-level. Among various In2O3 based sensors tested, the In2O3 thin film modified with Fe2O3 (1wt.%) showed extremely high sensitivity to dilute Cl2 gas of 0.2–5ppm. The Fe2O3–In2O3 sensor showed the sensitivity as high

  9. Elliptic flow of the dilute Fermi gas: From kinetics to hydrodynamics

    SciTech Connect

    Dusling, K.; Schaefer, T. [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2011-07-15

    We use the Boltzmann equation in the relaxation-time approximation to study the expansion of a dilute Fermi gas at unitarity. We focus, in particular, on the approach to the hydrodynamic limit. Our main findings are the following: (i) In the regime that has been studied experimentally hydrodynamic effects beyond the Navier-Stokes approximation are small. (ii) Mean-field corrections to the Boltzmann equation are not important. (iii) Experimental data imply that freezeout occurs very late, which means that the relaxation time remains smaller than the expansion time during the entire evolution of the system. (iv) The experimental results also imply that the bulk viscosity is significantly smaller than the shear viscosity of the system.

  10. Exponential approach to, and properties of, a non-equilibrium steady state in a dilute gas

    E-print Network

    Eric A. Carlen; Joel L. Lebowitz; Clement Mouhot

    2014-06-16

    We investigate a kinetic model of a system in contact with several thermal reservoirs at different temperatures $T_\\alpha$. Our system is a spatially uniform dilute gas whose internal dynamics is described by the nonlinear Boltzmann equation with Maxwellian collisions. Similarly, the interaction with reservoir $\\alpha$ is represented by a Markovian process that has the Maxwellian $M_{T_\\alpha}$ as its stationary state. We prove existence and uniqueness of a non-equilibrium steady state (NESS) and show exponential convergence to this NESS in a metric on probability measures introduced into the study of Maxwellian collisions by Gabetta, Toscani and Wenberg (GTW). This shows that the GTW distance between the current velocity distribution to the steady-state velocity distribution is a Lyapunov functional for the system. We also derive expressions for the entropy production in the system plus the reservoirs which is always positive.

  11. 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 ...

  12. 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

  13. Absorption of dilute SO 2 gas stream with conversion to polymeric ferric sulfate for use in water treatment

    Microsoft Academic Search

    Aron D Butler; Maohong Fan; Robert C Brown; Adrienne T Cooper; J. H van Leeuwen; Shihwu Sung

    2004-01-01

    Use of sulfur dioxide (SO2) in the production of polymeric ferric sulfate (PFS) was investigated. PFS is a highly effective coagulant useful in treatment of drinking water and wastewater, and could serve as a value-added sink for sulfur removed during coal gas cleanup. SO2 was absorbed from a dilute gas stream by sparging it into a bench-scale reactor containing a

  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. Quantifying gross fluxes of nitrous oxide and dinitrogen gas using a novel isotope pool dilution technique

    NASA Astrophysics Data System (ADS)

    Arn Teh, Yit; Yang, Wendy; Silver, Whendee L.

    2010-05-01

    One of the existing challenges in trace gas biogeochemistry lies in understanding the environmental controls on the net and gross fluxes of soil-derived compounds. This is because gross production and consumption fluxes of these gases often occur simultaneously or in close spatial proximity, making it difficult to make inferences about the effects of environmental variables (e.g. temperature, soil water content, porosity, redox, etc.) on gross fluxes based on bulk concentration measurements alone. One novel approach for quantifying gross fluxes of N2O and N2 is 'stable isotope pool dilution;' a technique that has been successfully applied to study bidirectional fluxes of other biogenic compounds, such as CH4 and halocarbons. To evaluate the efficacy of this method for quantifying gross N2O and N2 fluxes, we conducted a combined field and laboratory test of the pool dilution technique along side conventional measures of nitrification and denitrification. Experiments were conducted in a N-rich managed peatland pasture in the Sacramento-San Joaquin Delta, California, USA. Field and laboratory measurements were performed in a broad range of microforms and microtopes spanning a range of hydrologic and environmental conditions. Field experiments focussed on gross fluxes of N2O and N2 in upper soil horizons; the soil layers that exchange most rapidly with the atmosphere. Laboratory experiments indicated that 15N pool dilution compares favourably with more conventional measures of N2O and N2 flux, such as acetylene inhibition or the 15NO3- pulse-trace approach. Gross N2O fluxes greatly exceeded N2 fluxes by as much as an order of magnitude or more, and averaged 6.1 ± 2.2 mg N m-2 d-1, with a range from 0.06 to 63.13 mg N m-2 d-1. N2O:N2 emissions ratios generally exceeded 1 except along slopes, with an overall range of 0.2 to 30.9. NH4+ concentrations and denitrifying enzyme activity were the best predictors of gross N2O fluxes in the field (r2 = 0.65). Net N2O production rates explained 53 percent of the variability in gross N2 fluxes, whereas N2O:N2 ratios were best predicted by the combination of water-filled pore space and mineral N concentration (r2 = 0.44). This research highlights the potential of the pool dilution approach for quantifying gross fluxes of N2O and N2 from surface soils under both field and laboratory conditions. Future experiments will couple these measures of soil surface fluxes with push-pull methods for determining gross N2O and N2 fluxes at depth, and natural abundance isotopomer measurements to determine sources of N2O.

  16. [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

  17. Inert electrode connection

    DOEpatents

    Weyand, John D. (Greensburg, PA); Woods, Robert W. (New Kensington, PA); DeYoung, David H. (Plum Boro, PA); Ray, Siba P. (Plum Boro, PA)

    1985-01-01

    An inert electrode connection is disclosed wherein a layer of inert electrode material is bonded to a layer of conductive material by providing at least one intermediate layer of material therebetween comprising a predetermined ratio of inert material to conductive material. In a preferred embodiment, the connection is formed by placing in a die a layer of powdered inert material, at least one layer of a mixture of powdered inert material and conductive material, and a layer of powdered conductive material. The connection is then formed by pressing the material at 15,000-20,000 psi to form a powder compact and then densifying the powder compact in an inert or reducing atmosphere at a temperature of 1200.degree.-1500.degree. C.

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

    SciTech Connect

    Perruchot, Christian [Interfaces, Traitements, Organisation et Dynamique des Systemes (ITODYS) Universite Paris 7- Denis. Diderot, 1 Rue Guy de la Brosse, 75005 Paris (France); Chehimi, Mohamed M. [Interfaces, Traitements, Organisation et Dynamique des Systemes (ITODYS) Universite Paris 7- Denis. Diderot, 1 Rue Guy de la Brosse, 75005 Paris (France); Vaulay, Marie-Josephe [Interfaces, Traitements, Organisation et Dynamique des Systemes (ITODYS) Universite Paris 7- Denis. Diderot, 1 Rue Guy de la Brosse, 75005 Paris (France); Benzarti, Karim [Laboratoire Central des Ponts et Chaussees (LCPC), 58 Boulevard Lefevre, 75732 Paris Cedex 15 (France)]. 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)

  19. Analysis of pressure drop characteristics and methods for calculating gas and gas-solid flow in horizontal pipes for dilute coal conveying system

    SciTech Connect

    Weiguo Pan; Zuohe Chi; Yongjing Liao [Zhejiang Univ., Hangzhou (China)] [and others

    1997-07-01

    This article reported pressure drop characteristics and methods for calculating friction factors {lambda} 0 and {lambda}{sub {mu}} for gas and gas-solids flows, respectively, in straight horizontal pipes are summarized advantages seed. The and disadvantages of calculating friction factor {lambda}{sub {mu}} through dimensional analysis in comparison with model simulation are analyzed. It is pointed out that model simulation is more suitable to engineering use than dimensional analysis. According to experimental results of dilute gas-coal powder flow in straight horizontal pipes of the coal pulverization system in a power plant; an empirical formula and a theoretical formula for calculating friction factor {lambda}{sub {mu}} in straight horizontal pipes transporting dilute coal powder are obtained.

  20. 30 CFR 36.49 - Tests of exhaust-gas dilution system.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...test (see § 36.43) to determine that the concentrations of carbon dioxide, carbon monoxide, oxides of nitrogen, and aldehydes in the diluted exhaust shall be below the required concentrations specified in §...

  1. 30 CFR 36.49 - Tests of exhaust-gas dilution system.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...test (see § 36.43) to determine that the concentrations of carbon dioxide, carbon monoxide, oxides of nitrogen, and aldehydes in the diluted exhaust shall be below the required concentrations specified in §...

  2. 30 CFR 36.49 - Tests of exhaust-gas dilution system.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...test (see § 36.43) to determine that the concentrations of carbon dioxide, carbon monoxide, oxides of nitrogen, and aldehydes in the diluted exhaust shall be below the required concentrations specified in §...

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

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...test (see § 36.43) to determine that the concentrations of carbon dioxide, carbon monoxide, oxides of nitrogen, and aldehydes in the diluted exhaust shall be below the required concentrations specified in §...

  4. 30 CFR 36.49 - Tests of exhaust-gas dilution system.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...test (see § 36.43) to determine that the concentrations of carbon dioxide, carbon monoxide, oxides of nitrogen, and aldehydes in the diluted exhaust shall be below the required concentrations specified in §...

  5. 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.

  6. 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.

  7. 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.

  8. Partial discharge and breakdown mechanisms in ultra-dilute SF6 and PFC gases mixed with N2 gas

    NASA Astrophysics Data System (ADS)

    Okubo, H.; Yamada, T.; Hatta, K.; Hayakawa, N.; Yuasa, S.; Okabe, S.

    2002-11-01

    Because of the high global warming potential of SF6 gas, research on alternative gases for electrical insulation with a lower environmental impact is essential. Gas mixtures composed of electronegative gases and N2 gas have the advantage of the reduction of the amount of SF6 gas and of utilizing the synergistic effect in electrical insulation performance. We investigated the partial discharge (PD) and breakdown (BD) characteristics of SF6/N2 and PFC (C3F8/N2 and C2F6/N2) gas mixtures under non-uniform electric field conditions, by changing the dilute content of electronegative gases. As a result, the synergistic effect in SF6/N2 gas mixtures was verified to be higher than that in PFC/N2 gas mixtures. The physical mechanism from PD inception to BD was discussed with consideration of the difference in electronegativity of SF6 and PFC gases. Furthermore, we found that PD inception and PD-to-BD mechanisms changed at a content of 10 ppm for SF6 due to the electron attachment activity of SF6 gas. The change in the PD and BD mechanisms in C3F8/N2 and C2F6/N2 gas mixtures appeared at 0.1% content for C3F8 and at 1% content for C2F6.

  9. 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...

  10. Ab initio potential energy surface for the carbon dioxide molecule pair and thermophysical properties of dilute carbon dioxide gas

    NASA Astrophysics Data System (ADS)

    Hellmann, Robert

    2014-10-01

    A four-dimensional intermolecular potential energy surface (PES) for two rigid carbon dioxide molecules was determined from quantum-chemical ab initio calculations. Interaction energies for 1229 CO2-CO2 configurations were computed at the CCSD(T) level of theory using basis sets up to aug-cc-pVQZ supplemented with bond functions. An analytical site-site potential function with seven sites per CO2 molecule was fitted to the interaction energies. The PES was validated by calculating the second virial coefficient as well as viscosity and thermal conductivity in the dilute-gas limit.

  11. Inert gas wave soldering evaluation

    Microsoft Academic Search

    J. E. Altpeter; L. L. Kneisel; J. D. Baker

    1991-01-01

    Production modules were soldered using adipic acid\\/isopropanol as a flux and atomized formic acid to further enhance oxide reduction over the molten soldered module. The objectives of the evaluation were to assess system capability, measurable performance versus conventional wave soldering equipment performance, and environmental impact. The system capability for overall machine performance, from belt speeds to repeatable solder heights and

  12. Inert gas ion source program

    NASA Technical Reports Server (NTRS)

    Ramsey, W. D.

    1978-01-01

    THe original 12 cm hexagonal magneto-electrostatic containment discharge chamber has been optimized for argon and xenon operation. Argon mass utilization efficiencies of 65 to 77 percent were achieved at keeper-plus-main discharge energy consumptions of 200 to 458 eV/ion, respectively. Xenon performance of 84 to 96 percent mass utilization was realized at 203 to 350 eV/ion. The optimization process and test results are discussed.

  13. 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.

  14. 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.

  15. Gas Dynamic Features of Self Ignition of Non Diluted Fuel\\/Air Mixtures at High Pressure

    Microsoft Academic Search

    R. BLUMENTHAL; K. FIEWEGER; K. H. KOMP; G. ADOMEIT

    1997-01-01

    – The self ignition of several non diluted fuel\\/air mixtures at high pressureis studied. Hydrogen,rsc-ocrane and n-heptane have been used as fuels. Experimentshave been performedusing the shock tube technique. Various observation methods, such as recording of pressure and of light band emission and shadow cinematography have been applied. The type of self ignition 35 well as the ignition delay times

  16. Gas Dynamic Features of Self Ignition of Non Diluted Fuel\\/Air Mixtures at High Pressure

    Microsoft Academic Search

    R. BLUMENTHAL; K. FIEWEGER; K. H. KOMP; G. ADOMEIT

    1996-01-01

    The self ignition of several non diluted fuel\\/air mixtures at high pressure is studied. Hydrogen, iso-octane and n-heptane have been used as fuels. Experiments have been performed using the shock tube technique. Various observation methods, such as recording of pressure and of light band emission and shadow cinematography have been applied. The type of self ignition as well as the

  17. 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

  18. Inert dark matter

    SciTech Connect

    Dolle, Ethan M.; Su Shufang [Department of Physics, University of Arizona, Tucson, Arizona 85721 (United States)

    2009-09-01

    The lightest neutral scalar in the inert Higgs doublet model is a natural candidate for weakly interacting massive particle dark matter. In this paper, we analyzed the dark matter relic density in the inert Higgs doublet model. Various theoretical and experimental constraints are taken into account. We found that there are five distinctive regions that could provide the right amount of the relic density in the Universe. Four out of those five regions have a light particle spectrum which could be studied at the Large Hadron Collider.

  19. Effect of inert propellant injection on Mars ascent vehicle performance

    NASA Technical Reports Server (NTRS)

    Colvin, James E.; Landis, Geoffrey A.

    1992-01-01

    A Mars ascent vehicle is limited in performance by the propellant which can be brought from Earth. In some cases the vehicle performance can be improved by injecting inert gas into the engine, if the inert gas is available as an in-situ resource and does not have to be brought from Earth. Carbon dioxide, nitrogen, and argon are constituents of the Martian atmosphere which could be separated by compressing the atmosphere, without any chemical processing step. The effect of inert gas injection on rocket engine performance was analyzed with a numerical combustion code that calculated chemical equilibrium for engines of varying combustion chamber pressure, expansion ratio, oxidizer/fuel ratio, and inert injection fraction. Results of this analysis were applied to several candidate missions to determine how the required mass of return propellant needed in low Earth orbit could be decreased using inert propellant injection.

  20. 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.

  1. 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

  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 experimental testing of inerters

    Microsoft Academic Search

    Christakis Papageorgiou; Malcolm C. Smith

    2005-01-01

    This paper presents experimental results from the testing of mechanical networks involving inerter devices. The tests are carried out using a hydraulic ram actuator whose displacement is controlled in a closed-loop system. A methodology is proposed for the testing of inerter devices which amounts to the design of a buffer network to be connected in series with the inerter device

  4. Accurate measurements of infinite dilution activity coefficients using gas chromatography with static-wall-coated open-tubular columns.

    PubMed

    Xu, Qianqian; Su, Baogen; Luo, Xinyi; Xing, Huabin; Bao, Zongbi; Yang, Qiwei; Yang, Yiwen; Ren, Qilong

    2012-11-01

    Wall-coated open-tubular (WCOT) columns provide higher column efficiency and lower solute interfacial adsorption effect than packed columns. However, previous efforts used to measure the infinite dilution activity coefficient (?(?)) via a chromatographic technique have used packed columns, because the low carrier gas flow rate (U) and the small stationary phase amount (n(2)) in WCOT columns raise large errors. By rationally revising the ?(?)-calculation equation for static-wall-coated open-tubular column, we observed that U and n(2) are not necessarily needed and the resulting error could be reduced, and WCOT column gas chromatography subsequently became a superior method for the accurate ?(?) determination. In this study, we validate our revised ?(?)-calculation equation by measuring ?(?) in an ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate system, in which 55 organic compounds covering a wide range of functional groups were used as probe solutes and their ?(?) values in the ionic liquid were determined at 40.0, 50.0, and 60.0 °C. Experimental error analysis shows that our revised equation remarkably reduces the error compared to the common ?(?)-calculation equation. Our data is consistent with previously reported values obtained via other techniques, which further proves the credibility of our revised equation. The accurately determined ?(?) values can be directly used to calculate the partial molar excess enthalpy, selectivity, and capacity, which will benefit for the rapid screening of solvents (especially ionic liquids) in separation approaches. PMID:23039405

  5. Activity Coefficients at Infinite Dilution of Organic Compounds in Trihexyl(tetradecyl)phophonium Bis(trifluoromethylsulfonyl)imide Using Inverse Gas Chromatography

    SciTech Connect

    Revelli, Anne-Laure [Laboratoire de Thermodynamique des Milieux Polyphases, Nancy-Universite, Nancy, France; Sprunger, Laura [University of North Texas; Gibbs, Jennifer [University of North Texas; Acree, William [University of North Texas; Baker, Gary A [ORNL; Mutelet, Fabrice [Laboratoire de Thermodynamique des Milieux Polyphases, Nancy-Universite, Nancy, France

    2009-01-01

    Activity coefficients at infinite dilution of organic compounds in the ionic liquid (IL) trihexyl(tetradecyl) phosphonium bis(trifluoromethylsulfonyl)imide were determined using inverse gas chromatography at three temperatures, T ) (302.45, 322.35, and 342.45) K. Linear free energy relationship (LFER) correlations have been obtained for describing the gas-to-IL and water-to-IL partition coefficients.

  6. Determination of thermodynamic properties of isotactic poly(1-butene) at infinite dilution using density and inverse gas chromatography.

    PubMed

    Koz?owska, Marta Karolina; Doma?ska, Urszula; Lempert, Ma?gorzata; Rogalski, Marek

    2005-03-18

    The partial molar volumes, V1(M), and the molar volume of isotactic crystalline low-molecular-weight poly(1-butene), iPBu-1, V1, have been calculated from the measured density of {iPBu-1 + solvent (n-hexane, n-heptane, n-nonane, n-decane, p-xylene, cyclohexane and chloroform)} systems. Some of the thermodynamic quantities were also obtained for the iPBu-1 with eight hydrocarbons (n-octane, n-decane, n-undecane, n-dodecane, n-tridecane, o-xylene, m-xylene, p-xylene) by the method of inverse gas chromatography at various temperatures. The weight fraction activity coefficients of the solvent at infinite dilution, omega2(infinity) and the Flory-Huggins thermodynamic interaction parameters, chi21(infinity), between polymer and solvents were determined. The partial molar free energy, deltaG2(infinity), the partial molar heat of mixing, deltaH2(infinity), at infinite dilution and the polymer solubility parameter, delta1, were calculated. Additionally, the (solid + liquid) binary mixtures equilibria, SLE, of iPBu-1 with three hydrocarbons (n-octane, n-decane and m-xylene) were studied by a dynamic method. By performing these experiments over a large concentration range, the T-x phase diagrams of the polymer-solvent systems were constructed. The excess Gibbs energy models were used to describe the nonideal behaviour of the liquid phase. The omega2(infinity) were determined from the solubility measurements and were predicted by using the UNIFAC FV model. PMID:15830936

  7. PAFC performance loss due to CO2 dilution effect

    NASA Astrophysics Data System (ADS)

    Le, M. T.

    The sensitivity of dilution effects in anode fuel has been extensively examined for Westinghouse Phosphoric Acid Fuel Cells (PAFCs). These fuel cells were designed to be operated with reformed fuel generated from natural gas and other H2 rich fuels. The main nonhydrogen constituents of the studied fuels are CO2 and CO. This work was performed to study the real effect of CO2 diluting losses on these cells in various anode fuel mixtures with the CO2 concentration varying from 0 percent to as high as 53 percent by mole. Cell performance losses were evaluated over a utilization range of 40-85 percent and two current levels, 150 A and 320 A. The results obtained confirm that the Westinghouse PAFC could operate with high inert (CO2 or similar gases) concentration fuel.

  8. Dilute gas of ultracold two-level atoms inside a cavity; generalized Dicke model

    E-print Network

    Jonas Larson; Maciej Lewenstein

    2009-06-22

    We consider a gas of ultracold two-level atoms confined in a cavity, taking into account for atomic center-of-mass motion and cavity mode variations. We use the generalized Dicke model, and analyze separately the cases of a Gaussian, and a standing wave mode shape. Owing to the interplay between external motional energies of the atoms and internal atomic and field energies, the phase-diagrams exhibit novel features not encountered in the standard Dicke model, such as the existence of first and second order phase transitions between normal and superradiant phases. Due to the quantum description of atomic motion, internal and external atomic degrees of freedom are highly correlated leading to modified normal and superradiant phases.

  9. Implications of hydrodynamic fluctuations for the minimum shear viscosity of the dilute Fermi gas at unitarity

    NASA Astrophysics Data System (ADS)

    Romatschke, Paul; Young, Ryan Edward

    2013-05-01

    We confirm and expand on work by Chafin and Schäfer [Phys. Rev. A1050-294710.1103/PhysRevA.87.023629 87, 023629 (2013)] on hydrodynamic fluctuations in the unitary Fermi gas. Using the result for the equation of state from a recent MIT experiment, we derive lower bounds for ?/n and ?/s as a function of temperature. Reanalyzing recent quantum Monte Carlo data for the shear-viscosity spectral function, we point out a possible resolution for the tension between the viscosity bound ?/n?0.3 from Chafin and Schäfer and the quantum Monte Carlo results ?/n?0.2 from Wlazlowski, Magierski, and Drut [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.109.020406 109, 020406 (2012)] near the critical temperature.

  10. Design, fabrication, and testing of a full-scale breadboard nitrogen generator for fuel tank inerting application. Final report

    Microsoft Academic Search

    Manatt

    1977-01-01

    Aircraft fuel tank ullage may contain a mixture of fuel vapor in air that presents a fire and explosion hazard. This hazard can be eliminated if the air is replaced by an inert gas containing insufficient oxygen to allow ignition. Fuel tank inerting systems using onboard storage of liquid nitrogen to supply the inert gas were demonstrated by the FAA

  11. [Determination of mono- to tri-chlorinated dibenzo-p-dioxins and dibenzofurans in stack gas using isotope dilution high resolution gas chromatography-high resolution mass spectrometry].

    PubMed

    Tang, Chen; Liu, Qipeng; Tian, Zhenyu; Xie, Huiting; Wang, Mengjing; Liu, Wenbin

    2014-09-01

    A method for the determination of mono- to tri-chlorinated dibenzo-p-dioxins and dibenzofurans (mono- to tri-CDD/Fs) in stack gas using isotope dilution high resolution gas chromatography-high resolution mass spectrometry (HRGC-HRMS) was developed. The sam- ples were extracted by Soxhlet extraction, and then the extracts were concentrated and purified using a multilayer silica gel column and a basic alumina column. The analytes were separated by HRGC on a DB-5MS column (30 m x 0.25 mm x 0.25 ?m) and determined by HRMS. The identi- fication of mono- to tri-CDD/Fs was based on the retention times of 13C-labelled standard and the abundance ratios of the two exacted mass-to-charge ratios. The quantitative analysis was performed using the ratios of the integrated areas of the 13C-labelled standards. This method had the recoveries ranging from 66.6% to 112.5% and the relative standard deviations (RSD) ranging from 19.9% to 40.5% (n = 5). The limits of detection (LODs) of this method for the mono- to tri-CDD/Fs were ranging from 0.027 to 0.485 ?g/L. Three stack gas samples from waste incinerators were measured using this method, with the recoveries ranging from 85.7% to 137.0% and the concentrations ranging from 11.4 to 9,183 pg/Nm3. The results indicated that the method can be applied to the precise determination of mono- to tri-CDD/Fs at trace level in stack gas. PMID:25752087

  12. Isotope Dilution Gas Chromatographic-Mass Spectrometric Method for the Determination of Unconjugated Lignans and Isoflavonoids in Human Feces, with Preliminary Results in Omnivorous and Vegetarian Women

    Microsoft Academic Search

    H. Adlercreutz; T. Fotsis; M. S. Kurzer; K. Wahala; T. Makela; T. Hase

    1995-01-01

    We describe an isotope dilution gas chromatographic-mass spectrometric (GC\\/MS) method for the identification and quantitative determination of the lignans enterolactone, enterodiol, and matairesinol and the isoflavonoids daidzein, equol, O-desmethylangolensin, and genistein in feces. Following the addition of deuterated internal standards for all compounds, the feces samples are extracted and purified in several ion exchange chromatographic steps. Following formation of trimethylsilyl

  13. Validation of a gas chromatography-mass spectrometry isotope dilution method for the determination of 2-butoxyethanol and other common glycol ethers in consumer products.

    PubMed

    Tokarczyk, Ryszard; Jiang, Ying; Poole, Gary; Turle, Richard

    2010-10-29

    A gas chromatography-mass spectrometry isotope dilution (GC-MS ID) method was developed and tested for the determination of 14 common glycol ethers in consumer products. Stable isotope labelled standards, 2-methoxyethanol-D(7) and 2-butoxyethanol-(13)C(2) (CDN isotopes) were employed to enhance the accuracy and precision of the glycol ethers determination. A 1000-fold sample dilution with methanol was applied to avoid column overload and contamination. At this dilution matrix effects were in most cases negligible and did not interfere with the analysis. The instrument detection limit (IDL) for analysed compounds varied from 0.01 to 1 ?g/mL; while the estimated limit of quantification (LoQ) varied between different glycol ethers from 0.02 to 3.4 ?g/mL. Calibration was tested in the range of 0.1-200 ?g/mL and showed that the linear fit is upheld from 0.1 to 10 ?g/mL, and extends beyond this range for some of the analytes. Recoveries of glycol ethers from products with different matrices were similar. The recoveries varied from 87% to 116% between the analysed compounds, while measurements precision varied between 2% and 14%. The method is applicable to products with glycol ether concentrations above 0.002-0.2% (w/w). The concentration range can be extended below the specified limits by decreasing the dilution factor; however, with lower dilution the sample matrix effect is expected to be stronger. Products with very high concentrations of glycol ether (>20%) may need to be further diluted prior to injection to avoid column overload. The method can be used for testing liquid and aerosol products designed for household use, such as cleaners, paints, solvents and paint stripers, for compliance and enforcement of regulations which limit glycol ethers content. PMID:20855078

  14. 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

  15. Thermal Effects Accompanying Spontaneous Ignitions in Gases. I. An Investigation of the Heating Effects Which Accompany the Rapid Admission of Inert Gas to an Evacuated Vessel

    Microsoft Academic Search

    D. H. Fine; P. Gray; R. Mackinven

    1970-01-01

    In experiments on spontaneous ignition of gases, transient temperature changes normally accompany the entry of gases to evacuated vessels. They may invalidate much quantitative experimental work and give rise to spurious observations. In the present investigation, temperature-time histories accompanying gas entry have been mapped with a fine (13 mu m) thermocouple for many positions in a spherical vessel. It is

  16. A Common Single-Site Pt(II)-O(OH)x- Species Stabilized by Sodium on "Active" and "Inert" Supports Catalyzes the Water-Gas Shift Reaction.

    PubMed

    Yang, Ming; Liu, Jilei; Lee, Sungsik; Zugic, Branko; Huang, Jun; Allard, Lawrence F; Flytzani-Stephanopoulos, Maria

    2015-03-18

    While it has long been known that different types of support oxides have different capabilities to anchor metals and thus tailor the catalytic behavior, it is not always clear whether the support is a mere carrier of the active metal site, itself not participating directly in the reaction pathway. We report that catalytically similar single-atom-centric Pt sites are formed by binding to sodium ions through -O ligands, the ensemble being equally effective on supports as diverse as TiO2, L-zeolites, and mesoporous silica MCM-41. Loading of 0.5 wt % Pt on all of these supports preserves the Pt in atomic dispersion as Pt(II), and the Pt-O(OH)x- species catalyzes the water-gas shift reaction from ?120 to 400 °C. Since the effect of the support is "indirect," these findings pave the way for the use of a variety of earth-abundant supports as carriers of atomically dispersed platinum for applications in catalytic fuel-gas processing. PMID:25746682

  17. Partial discharge and breakdown mechanisms in ultra-dilute SF6 and PFC gases mixed with N2 gas

    Microsoft Academic Search

    H. Okubo; T. Yamada; K. Hatta; N. Hayakawa; S. Yuasa; S. Okabe

    2002-01-01

    Because of the high global warming potential of SF6 gas, research on alternative gases for electrical insulation with a lower environmental impact is essential. Gas mixtures composed of electronegative gases and N2 gas have the advantage of the reduction of the amount of SF6 gas and of utilizing the synergistic effect in electrical insulation performance. We investigated the partial discharge

  18. Influence of the inter-electrode distance on the production of nanoparticles by means of atmospheric pressure inert gas dc glow discharge

    NASA Astrophysics Data System (ADS)

    Hontañón, Esther; María Palomares, Jose; Guo, Xiaoai; Engeln, Richard; Nirschl, Hermann; Kruis, Frank Einar

    2014-10-01

    This work is aimed at investigating the influence of the inter-electrode spacing on the production rate and size of nanoparticles generated by evaporating a cathode on an atmospheric pressure dc glow discharge. Experiments are conducted in the configuration of two vertically aligned cylindrical electrodes in upward coaxial flow with copper as a consumable cathode and nitrogen as a carrier gas. A constant current of 0.5 A is delivered to the electrodes and the inter-electrode distance spanned from 0.5 to 10 mm. Continuous stable nanoparticle production is attained by optimal coaxial flow convection cooling of the cathode. Both the particle production rate and the primary particle size increase with the inter-electrode spacing up to nearly 5 mm and strongly decrease with an increasing inter-electrode distance beyond 5 mm. Production rates in the range of 1 mg h-1 of very small nanoparticles (<10 nm) are attained by a micro glow discharge (<1 mm) while glow discharges of intermediate sizes (<5 mm) result in production rates of up to 10 mg h-1 and primary particles of sizes between 10 and 20 nm. No correlation is found between the measured spatially averaged plasma parameters and nanoparticle production. Since the latter is largely determined by the properties of the cathode surface, spatially resolved spectrometric measurements are needed to discern between the positive column and the cathode region of the glow discharge plasma.

  19. Gas chromatography-combustion-mass spectrometry with postcolumn isotope dilution for compound-independent quantification: its potential to assess HS-SPME procedures.

    PubMed

    Cueto Díaz, Sergio; Ruiz Encinar, Jorge; Sanz-Medel, Alfredo; García Alonso, J Ignacio

    2010-08-15

    A quadrupole GC-MS instrument with an electron ionization (EI) source has been modified to enable application of postcolumn isotope dilution analysis for the standardless quantification of organic compounds injected in the gas chromatograph. Instrumental modifications included the quantitative conversion of the separated compounds into CO(2), using a postcolumn combustion furnace, and the subsequent mixing of the gas with a constant flow of (13)CO(2) diluted in helium. The online measurement of the (12)CO(2)/(13)CO(2) (44/45) ratio in the EI-MS allowed us to obtain quantitative data without resorting to compound-specific standards. Validation of the procedure involved the analysis of standard solutions containing different families of organic compounds (C(9)-C(20) linear hydrocarbons, BTEX and esters) obtaining satisfactory results in all cases in terms of absolute errors (<6%) and precision (<4% RSD). The developed procedure showed excellent linearity over the range assayed (2 orders of magnitude) and adequate detection limits for carbon containing compounds (0.8 pg C s(-1)). The generic value of this compound-independent calibration approach was assessed by studying the quantitative performance of Head Space-Solid Phase Microextraction (HS-SPME). The proposed compound-independent quantification by EI-MS permits comparison of the performance of different fibers by assessing analyte recoveries with extreme robustness, simplicity, and precision. PMID:20704376

  20. 40 CFR 1065.546 - Validation of minimum dilution ratio for PM batch sampling.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...diluted flow), dilution air flow, and dilute exhaust...based on the measured intake air molar flow rate and the...flow rate based on intake air, fuel rate measurements, and...Determine minimum dilution ratio based on tracer gas...

  1. 40 CFR 1065.546 - Validation of minimum dilution ratio for PM batch sampling.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...diluted flow), dilution air flow, and dilute exhaust...based on the measured intake air molar flow rate and the...flow rate based on intake air, fuel rate measurements, and...Determine minimum dilution ratio based on tracer gas...

  2. -Based Cermet Inert Anodes for Aluminum Electrolysis

    NASA Astrophysics Data System (ADS)

    Tian, ZhongLiang; Lai, YanQing; Li, ZhiYou; Chai, DengPeng; Li, Jie; Liu, YeXiang

    2014-11-01

    The new aluminum electrolysis technology based on inert electrodes has received much interest for several decades because of the environment and energy advantages. The key to realize this technique is the inert anode. This article presents China's recent developments of NiFe2O4-based cermet inert anodes, which include the optimization of material performance, the joint between the cermet inert anode and metallic bar, as well as the results of 20 kA pilot testing for a large-size inert anode group. The problems NiFe2O4-based cermet inert anodes face are also discussed.

  3. 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

  4. 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.

  5. Asymmetric Inert Scalar Dark Matter

    E-print Network

    Mikael Dhen; Thomas Hambye

    2015-03-20

    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.

  6. Determination of the alkylpyrazine composition of coffee using stable isotope dilution-gas chromatography-mass spectrometry (SIDA-GC-MS).

    PubMed

    Pickard, Stephanie; Becker, Irina; Merz, Karl-Heinz; Richling, Elke

    2013-07-01

    A stable isotope dilution analysis based on gas chromatography-mass spectrometry analysis (SIDA-GC-MS) was developed for the quantitative analysis of 12 alkylpyrazines found in commercially available coffee samples. These compounds contribute to coffee flavor. The accuracy of this method was tested by analyzing model mixtures of alkylpyrazines. Comparisons of alkylpyrazine-concentrations suggested that water as extraction solvent was superior to dichloromethane. The distribution patterns of alkylpyrazines in different roasted coffees were quite similar. The most abundant alkylpyrazine in each coffee sample was 2-methylpyrazine, followed by 2,6-dimethylpyrazine, 2,5-dimethylpyrazine, 2-ethylpyrazine, 2-ethyl-6-methylpyrazine, 2-ethyl-5-methylpyrazine, and 2,3,5-trimethylpyrazine, respectively. Among the alkylpyrazines tested, 2,3-dimethylpyrazine, 2-ethyl-3-methylpyrazine, 2-ethyl-3,6-dimethylpyrazine, and 2-ethyl-3,5-dimethylpyrazine revealed the lowest concentrations in roasted coffee. By the use of isotope dilution analysis, the total concentrations of alkylpyrazines in commercially available ground coffee ranged between 82.1 and 211.6 mg/kg, respectively. Decaffeinated coffee samples were found to contain lower amounts of alkylpyrazines than regular coffee samples by a factor of 0.3-0.7, which might be a result of the decaffeination procedure. PMID:23745606

  7. Infrared reflectivity spectra of gas-source molecular beam epitaxy grown dilute InNxAs1-x/InP (001)

    NASA Astrophysics Data System (ADS)

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

    2013-02-01

    Vibrational spectra of gas-source molecular beam epitaxy grown dilute InNxAs1-x/InP (001) alloys are obtained using a Fourier-transform infrared (IR) spectroscopy. A triply degenerate NAs local vibrational mode of Td-symmetry is observed near 438 cm-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 NAs local mode into a doublet for the NAs-Ga1(In1)In3(Ga3) pair-defect of C3v-symmetry is consistent with our simulated results based on a sophisticated Green's function theory.

  8. Ultrasonication extraction and gel permeation chromatography clean-up for the determination of polycyclic aromatic hydrocarbons in edible oil by an isotope dilution gas chromatography–mass spectrometry.

    PubMed

    Wang, Jian-Hua; Guo, Cui

    2010-07-01

    An analytical method for the determination of US EPA priority pollutant 16 polycyclic aromatic hydrocarbons (PAHs) in edible oil was developed by an isotope dilution gas chromatography-mass spectrometry (GC-MS). Extraction was performed with ultrasonication mode using acetonitrile as solvent, and subsequent clean-up was applied using narrow gel permeation chromatographic column. Three deuterated PAHs surrogate standards were used as internal standards for quantification and analytical quality control. The limits of quantification (LOQs) were globally below 0.5 ng/g, the recoveries were in the range of 81-96%, and the relative standard deviations (RSDs) were lower than 20%. Further trueness assessment of the method was also verified through participation in international cocoa butter proficiency test (T0638) organised by the FAPAS with excellent results in 2008. The results obtained with the described method were satisfying (z ? 2). The method has been applied to determine PAH in real edible oil samples. PMID:20627308

  9. Free electron in compressed inert gases

    SciTech Connect

    Gordon, E. B. [Russian Academy of Sciences, Institute of Problems of Chemical Physics (Russian Federation)], E-mail: gordon@ficp.ac.ru; Smirnov, B. M. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    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.

  10. 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. [GE Energy, Santa Ana, CA (United States)

    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.

  11. Inert doublet model and LEP II limits

    SciTech Connect

    Lundstroem, Erik; Gustafsson, Michael; Edsjoe, Joakim [Department of Physics, Stockholm University, AlbaNova University Center, SE - 106 91 Stockholm (Sweden); INFN, Sezione di Padova, Department of Physics 'Galileo Galilei', Via Marzolo 8, I-35131, Padua (Italy) and Department of Physics, Stockholm University, AlbaNova University Center, SE - 106 91 Stockholm (Sweden); Department of Physics, Stockholm University, AlbaNova University Center, SE - 106 91 Stockholm (Sweden)

    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.

  12. 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

  13. 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.

  14. Analysis of permethrin isomers in composite diet samples by molecularly imprinted solid-phase extraction and isotope dilution gas chromatography-ion trap mass spectrometry.

    PubMed

    Vonderheide, Anne P; Boyd, Brian; Ryberg, Anna; Yilmaz, Ecevit; Hieber, Thomas E; Kauffman, Peter E; Garris, Sherry T; Morgan, Jeffrey N

    2009-05-29

    Determination of an individual's aggregate dietary ingestion of pesticides entails analysis of a difficult sample matrix. Permethrin-specific molecularly imprinted polymer (MIP) solid-phase extraction cartridges were developed for use as a sample preparation technique for a composite food matrix. Vortexing with acetonitrile and centrifugation were found to provide optimal extraction of the permethrin isomers from the composite foods. The acetonitrile (with 1% acetic acid) was mostly evaporated and the analytes reconstituted in 90:10 water/acetonitrile in preparation for molecularly imprinted solid-phase extraction. Permethrin elution was accomplished with acetonitrile and sample extracts were analyzed by isotope dilution gas chromatography-ion trap mass spectrometry. Quantitation of product ions provided definitive identification of the pesticide isomers. The final method parameters were tested with fortified composite food samples of varying fat content (1%, 5%, and 10%) and recoveries ranged from 99.3% to 126%. Vegetable samples with incurred pesticide levels were also analyzed with the given method and recoveries were acceptable (81.0-95.7%). Method detection limits were demonstrated in the low ppb range. Finally, the applicability of the MIP stationary phase to extract other pyrethroids, specifically cyfluthrin and cypermethrin, was also investigated. PMID:19393156

  15. Quantification of 13 priority polycyclic aromatic hydrocarbons in human urine by headspace solid-phase microextraction gas chromatography-isotope dilution mass spectrometry.

    PubMed

    Campo, Laura; Mercadante, Rosa; Rossella, Federica; Fustinoni, Silvia

    2009-01-12

    Polycyclic aromatic hydrocarbons (PAHs) are common environmental pollutants in both living and working environments. The aim of this study was the development of a headspace solid-phase microextraction gas chromatography-isotope dilution mass spectrometry (HS-SPME/GC-IDMS) method for the simultaneous quantification of 13 PAHs in urine samples. Different parameters affecting PAHs extraction by HS-SPME were considered and optimized: type/thickness of fiber coatings, extraction temperature/time, desorption temperature/time, ionic strength and sample agitation. The stability of spiked PAHs solutions and of real urine samples stored up to 90 days in containers of different materials was evaluated. In the optimized method, analytes were absorbed for 60min at 80 degrees C in the sample headspace with a 100mum polydimethylsiloxane fiber. The method is very specific, with linear range from the limit of quantification to 8.67 x 10(3)ngL(-1), a within-run precision of <20% and a between-run precision of <20% for 2-, 3- and 4-ring compounds and of <30% for 5-ring compounds, trueness within 20% of the spiked concentration, and limit of quantification in the 2.28-2.28 x 10(1)ngL(-1) range. An application of the proposed method using 15 urine samples from subjects exposed to PAHs at different environmental levels is shown. PMID:19084626

  16. Regional water-quality analysis of 2,4-D and dicamba in river water using gas chromatography-isotope dilution mass spectrometry

    USGS Publications Warehouse

    Thurman, E.M.; Zimmerman, L.R.; Aga, D.S.; Gilliom, R.J.

    2001-01-01

    Gas chromatography with isotope dilution mass spectrometry (GC-MS) and enzyme-linked immunosorbent assay (ELISA) were used in regional National Water Quality Assessment studies of the herbicides, 2,4-D and dicamba, in river water across the United States. The GC-MS method involved solid-phase extraction, derivatized with deutemted 2,4-D, and analysis by selected ion monitoring. The ELISA method was applied after preconcentration with solid-phase extraction. The ELISA method was unreliable because of interference from humic substances that were also isolated by solid-phase extraction. Therefore, GC-MS was used to analyzed 80 samples from river water from 14 basins. The frequency of detection of dicamba (28%) was higher than that for 2,4-D (16%). Concentrations were higher for dicamba than for 2,4-D, ranging from less than the detection limit (<0.05 ??g/L) to 3.77 ??g/L, in spite of 5 times more annual use of 2,4-D as compared to dicamba. These results suggest that 2,4-D degrades more rapidly in the environment than dicamba.

  17. Development of an equilibrium headspace gas chromatographic method for the measurement of noncovalent association and partitioning of n-alkylbenzenes at infinite dilution in fulvic acid pseudophase.

    PubMed

    Eljack, Mahmoud D; Wilson, Rachael E; Hussam, Abul; Khan, Shahamat U

    2015-02-27

    Fulvic acid (FA), the most important water soluble fraction of humic substances in nature, is known to form aggregate pseudophase and complexes with organic and inorganic species. Here, we report a novel equilibrium headspace gas chromatography (eHSGC) and a two-step reaction model to measure n-alkylbenzene-FA association constant (K11) and n-alkylbenzene-pseudophase FAn association constant (Kn1) without solute concentration and response factor. The K11 and Kn1 values were 2-3 orders of magnitude higher than those for sodium dodecylsulfate. Changes in peak area were used to calculate the critical FA-aggregation concentration (cfc), mole fraction based partition coefficients (Kx), activity coefficients of solute inside the aggregate pseudophase (?m(?)), and transfer free energies of alkyl CH2 at infinite dilution. The cfc was found to be 10±0.5?M. The Kx values are of the order of 10(7) in the FA-aggregate pseudophase. The data shows that benzene has the lowest (0.0002) and n-butylbenzene has the highest (0.01) ?m(?) values, which are seven orders of magnitude smaller than ?w(?) in water. The transfer free energy of association of a CH2 group, -155cal/mol, compared to that of benzene, -9722cal/mol, indicates that the FA-aggregate pseudophase is more polarizable benzene-like and less n-alkane aliphatic-like. PMID:25622521

  18. [Determination of urinary cotinine of children exposed to passive smoking by stable isotope dilution gas chromatography-triple quadrupole mass spectrometry].

    PubMed

    Wang, Yun; Huang, Zhiqiang; Ye, Ying; Zhang, Ying; Xiao, Shuiyuan

    2014-06-01

    An analytical method for the determination of urinary cotinine of children exposed to passive smoking was established based on stable isotope dilution by gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS). The samples were extracted and purified with chloroform. The extracts were determined by GC-MS/MS in multiple reaction monitoring (MRM) mode. The cotinine-d3 as an isotope internal standard was applied to quantify and confirm the urinary cotinine of children exposed to passive smoking. The method had a good linearity from 0.1 microg/L to 10 microg/L with the correlation coefficient (r) > 0.998. The recoveries of the cotinine in blank urine were from 79.2% to 112.8% at spiked levels of 0.1, 1.0 and 10 microg/ L, with relative standard deviations (RSDs) from 2.1% to 5. 8%. The limit of quantification ( LOQ) of the method was 0.1 microg/L. The developed method is accurate, sensitive, rapid and can be applied to detect urinary cotinine of children exposed to passive smoking at home. PMID:25269267

  19. Simultaneous analysis of phthalates, adipate and polycyclic aromatic hydrocarbons in edible oils using isotope dilution-gas chromatography-mass spectrometry.

    PubMed

    Oh, Min-Seok; Lee, Seon-Hwa; Moon, Myeong Hee; Lee, Dong Soo; Park, Hyun-Mee

    2014-01-01

    A method for simultaneous determination of 12 priority phthalates, adipate and polycyclic aromatic hydrocarbons (PAHs) in edible oils by isotope dilution-gas chromatography-mass spectrometry (ID-GC-MS) was developed for fast, accurate and trace analysis. The extraction and clean-up procedures were optimised, and using stable isotope-labelled internal standards for each analyte, relative standard deviations (RSDs) of 0.92-10.6% and spiked sample recoveries of 80.6-97.8% were obtained. Limits of detection for PAHs were in the range of 0.15-0.77 µg/kg and those for phthalates were in the range of 4.6-10.0 µg/kg. The calibration curves exhibited good linearities with regression coefficients of R(2) ? 0.99. Twelve edible oils were examined to evaluate the efficiency of this method. Among the 12 analytes, dibutyl phthalates (DBP), diethylhexyl phthalates (DEHP), diethylhexyl adipate (DEHA), benzo[a]anthracene (B[a]A), chrysene (Chry) and benzo[b]fluoranthene (B[b]F) were detected in the range of 1.17-806 µg/kg. PMID:25029399

  20. Flammability limits of dusts: Minimum inerting concentrations

    SciTech Connect

    Dastidar, A.G.; Amyotte, P.R. [Dalhousie Univ., Halifax, Nova Scotia (Canada). Dept. of Chemical Engineering] [Dalhousie Univ., Halifax, Nova Scotia (Canada). Dept. of Chemical Engineering; Going, J.; Chatrathi, K. [Fike Corp., Blue Springs, MO (United States)] [Fike Corp., Blue Springs, MO (United States)

    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. 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.

  2. Gamma Inert Sterilization: A Solution to Polyethylene Oxidation?

    PubMed Central

    Medel, Francisco J.; Kurtz, Steven M.; Hozack, William J.; Parvizi, Javad; Purtill, James J.; Sharkey, Peter F.; MacDonald, Daniel; Kraay, Matthew J.; Goldberg, Victor; Rimnac, Clare M.

    2009-01-01

    Background: In the 1990s, oxidation was found to occur in ultra-high molecular weight polyethylene total joint replacement components following gamma irradiation and prolonged shelf aging in air. Orthopaedic manufacturers developed barrier packaging to reduce oxidation during and after radiation sterilization. The present study explores the hypothesis that polyethylene components sterilized in a low-oxygen environment undergo similar in vivo oxidative mechanisms as inserts sterilized in air. In addition, the potential influence of the different sterilization processes on the wear performance of the polyethylene components was examined. Methods: An analysis of oxidation, wear, and surface damage was performed for forty-eight acetabular liners and 123 tibial inserts. The mean implantation time was 12.3 ± 3.7 years for thirty-one acetabular liners that had been gamma sterilized in air and 4.0 ± 2.5 years for the seventeen acetabular liners that had been gamma sterilized in inert gas. The mean implantation time was 11.0 ± 3.2 years for the twenty-six tibial inserts that had been sterilized in air and 2.8 ± 2.2 years for the ninety-seven tibial inserts that had been gamma sterilized in inert gas. Oxidation and hydroperoxide levels were characterized in loaded and unloaded regions of the inserts. Results: Measurable oxidation and oxidation potential were observed in all cohorts. The oxidation and hydroperoxide levels were regional. Surfaces with access to body fluids were more heavily oxidized than protected bearing surfaces were. This variation appeared to be greater in historical (gamma-in-air-sterilized) components. Regarding wear performance, historical and conventional acetabular liners showed similar wear penetration rates, whereas a low incidence of delamination was confirmed for the conventional tibial inserts in the first decade of implantation. Conclusions: The present study explores the impact of industry-wide changes in sterilization practices for polyethylene. We found lower oxidation and oxidation potential in the conventional acetabular liners and tibial inserts that had been gamma sterilized in inert gas as compared with the historical components that had been gamma sterilized in air. However, we also found strong evidence that conventional components undergo mechanisms of in vivo oxidation similar to those observed following gamma irradiation in air. In addition, gamma sterilization in inert gas did not provide polyethylene with a significant improvement in terms of wear resistance as compared with gamma sterilization in air, except for a lower incidence of delamination in the first decade of implantation for tibial inserts. Clinical Relevance: Our research demonstrates that gamma inert sterilization may have improved, but not completely solved, the problem of polyethylene oxidation for hip and knee arthroplasty. PMID:19339568

  3. Estradiol-17 beta quantified in serum by isotope dilution-gas chromatography-mass spectrometry: reversed-phase C18 high-performance liquid chromatography compared with immuno-affinity chromatography for sample pretreatment.

    PubMed

    Thienpont, L M; Verhaeghe, P G; Van Brussel, K A; De Leenheer, A P

    1988-10-01

    Here, isotope dilution-gas chromatography-mass spectometry is used as a reference technique for determining the concentration of estradiol-17 beta in candidate human serum Reference Material. The accuracy of assigned concentrations in biologic materials is not only determined by instrumental performance, it also depends greatly on the selectivity of the procedure for isolating the analyte from the biological matrix, an issue which we consider insufficiently addressed in the literature. We introduced reversed-phase C18 high-performance liquid chromatography as a fractionation procedure in addition to the commonly used solvent extraction and column chromatography on Sephadex LH-20. The validity of this approach as part of a Reference Method for measurement of estradiol-17 beta by isotope dilution-gas chromatography-mass spectrometry was investigated by comparison with immuno-affinity chromatography, which on theoretical grounds is generally considered as highly selective. PMID:3168218

  4. Modeling of Decelerating and Steady State Turbulent Gas-Solids Dilute Phase Flow of Large Particles in a Vertical Pneumatic Transport Line.

    NASA Astrophysics Data System (ADS)

    Paccione, John D.

    Decelerating and steady state turbulent dilute phase flow has been studied using one millimeter glass spheres in a 28.45 mm ID grounded stainless steel transport line. The analysis used the one dimensional two-fluid model containing continuity and individual phase momentum balances from the work of Capes and Nakamura (14), (84) and an analytical representation of the experimental pressure profile to produce a standard analytical procedure. Steady state slip Reynolds numbers ranged from 461 to 986 and the pipe Reynolds number was of the order of 20,000. Experimental observations and literature evidence is presented to support the existence of a particle free region near the wall making it possible to neglect particle wall friction effects in the model. The fluid-wall effect was modeled assuming turbulent pipe flow in a smooth tube without particles because the entrained spheres do not impart momentum to the tube wall. The steady state drag coefficient C_ {DN} decreases from values at Re _{p} = 461 which essentially match the standard drag curve to that of 0.13 at Re_ {p} = 986. The deviation between C _{DN} and the standard drag curve are attributed to freestream turbulence. These findings invalidate the use of the standard drag curve for modeling vertical pneumatic transport. The decelerating drag coefficient (C_ {DD}) has been correlated in terms of the modulus of deceleration, solids concentration and the particle to gas density ratio. The effect of deceleration on the drag coefficient is shown to be small relative to that of freestream turbulence. An analytical expression was developed which relates the pressure drop across the deceleration region to the inlet voidage.

  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. Monitoring urinary metabolites resulting from sulfur mustard exposure in rabbits, using highly sensitive isotope-dilution gas chromatography-mass spectrometry.

    PubMed

    Nie, Zhiyong; Zhang, Yajiao; Chen, Jia; Lin, Ying; Wu, Bidong; Dong, Yuan; Feng, Jianlin; Liu, Qin; Xie, Jianwei

    2014-08-01

    A highly sensitive method for the determination of sulfur mustard (SM) metabolites thiodiglycol (TDG) and thiodiglycol sulfoxide (TDGO) in urine was established and validated using isotope-dilution negative-ion chemical ionization (NICI) gas chromatography-mass spectrometry (GC-MS). TDGO in the samples was reduced with TiCl3, and then determined together with TDG as a single analyte. The sample preparation procedures, including two solid-phase-extraction (SPE) clean-up steps, were optimized to improve the sensitivity of the method. The limits of detection (LOD) for both TDG and TDG plus TDGO (TDG + TDGO) were 0.1 ng mL(-1), and the limits of quantitation (LOQ) for both were 0.3 ng mL(-1). The method was used in a rabbit cutaneous SM exposure model. Domestic rabbits were exposed to neat liquid SM at three dosage levels (0.02, 0.05, and 0.15 LD50), and the urinary excretion of four species of hydrolysis metabolites, namely free TDG, free plus conjugated TDG (total TDG), free TDG + TDGO, and free plus conjugated TDG + TDGO (total TDG + TDGO), was evaluated to investigate the metabolic processes. The total urinary excretion profiles of the metabolites, including the peak time, time window, and dose-response and time-response relationships, were clarified. The results revealed that the concentrations of TDG and TDG + TDGO in the urine increased quickly and then decreased rapidly in the first two days after SM exposure. The cumulative amount of total TDG + TDGO excreted in urine during the first five days accounted for 0.5-1% of the applied dose of SM. It is also concluded that TDG and TDGO in urine existed mainly in free form, the levels of glucuronide and of sulfate conjugates of TDG or TDGO were very low, and most hydrolysis metabolites were present in the oxidized form (TDGO). The study indicates that the abnormal increase of TDG and TDGO excretion levels can be used as a diagnostic indicator and establishes a reference time-window for retrospective analysis and sampling after SM exposure. PMID:24924210

  7. Simultaneous Determination of Creatinine and Creatine in Human Serum by Double-Spike Isotope Dilution Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) and Gas Chromatography-Mass Spectrometry (GC-MS).

    PubMed

    Fernández-Fernández, Mario; Rodríguez-González, Pablo; Añón Álvarez, M Elena; Rodríguez, Felix; Menéndez, Francisco V Álvarez; Alonso, J Ignacio García

    2015-04-01

    This work describes the first multiple spiking isotope dilution procedure for organic compounds using (13)C labeling. A double-spiking isotope dilution method capable of correcting and quantifying the creatine-creatinine interconversion occurring during the analytical determination of both compounds in human serum is presented. The determination of serum creatinine may be affected by the interconversion between creatine and creatinine during sample preparation or by inefficient chemical separation of those compounds by solid phase extraction (SPE). The methodology is based on the use differently labeled (13)C analogues ((13)C1-creatinine and (13)C2-creatine), the measurement of the isotopic distribution of creatine and creatinine by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and the application of multiple linear regression. Five different lyophilized serum-based controls and two certified human serum reference materials (ERM-DA252a and ERM-DA253a) were analyzed to evaluate the accuracy and precision of the proposed double-spike LC-MS/MS method. The methodology was applied to study the creatine-creatinine interconversion during LC-MS/MS and gas chromatography-mass spectrometry (GC-MS) analyses and the separation efficiency of the SPE step required in the traditional gas chromatography-isotope dilution mass spectrometry (GC-IDMS) reference methods employed for the determination of serum creatinine. The analysis of real serum samples by GC-MS showed that creatine-creatinine separation by SPE can be a nonquantitative step that may induce creatinine overestimations up to 28% in samples containing high amounts of creatine. Also, a detectable conversion of creatine into creatinine was observed during sample preparation for LC-MS/MS. The developed double-spike LC-MS/MS improves the current state of the art for the determination of creatinine in human serum by isotope dilution mass spectrometry (IDMS), because corrections are made for all the possible errors derived from the sample preparation step. PMID:25751287

  8. 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.

  9. Inertance Tube Optimization for Pulse Tube Refrigerators

    NASA Astrophysics Data System (ADS)

    Radebaugh, Ray; Lewis, M.; Luo, E.; Pfotenhauer, J. M.; Nellis, G. F.; Schunk, L. A.

    2006-04-01

    The efficiency of regenerative refrigerators is generally maximized when the pressure and flow are in phase near the midpoint of the regenerator. Such a phase relationship minimizes the amplitude of the mass flow for a given acoustic power flow through the regenerator. To achieve this phase relationship in a pulse tube refrigerator requires that the flow at the warm end of the pulse tube lag the pressure by about 60 degrees. The inertance tube allows for the flow to lag the pressure, but such a large phase shift is only possible with relatively large acoustic power flows. In small pulse tube cryocoolers the efficiency is improved by maximizing the phase shift in the inertance tube. This paper describes a simple transmission line model of the inertance tube, which is used to find the maximum phase shift and the corresponding diameter and length of the optimized inertance tube. Acoustic power flows between 1 and 100 W are considered in this study, though the model may be valid for larger systems as well. For large systems the model can be used to find the minimum reservoir volume that in combination with the inertance tube provides a phase shift of 60 degrees. This transmission line model is compared with some experimental results on a small-diameter inertance tube and found to agree quite well provided some heat transfer is taken into account. Design graphs for a frequency of 60 Hz and an average pressure of 2.5 MPa are presented for different pressure ratios and for both adiabatic and isothermal conditions.

  10. 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.

  11. Passive suspensions incorporating inerters for railway vehicles

    Microsoft Academic Search

    Jason Zheng Jiang; Alejandra Z. Matamoros-Sanchez; Roger M. Goodall; Malcolm C. Smith

    2012-01-01

    This paper investigates the possibility of improving the performance of railway vehicle suspensions by incorporating a newly developed mechanical device known as the inerter. A comparative study of several low-complexity passive suspension layouts is made. Improved performance for the lateral and vertical ride comfort, as well as lateral body movement when curving are demonstrated in comparison with the conventional suspension

  12. Polyvinyl alcohol battery separator containing inert filler

    Microsoft Academic Search

    D. W. Sheibley; L. C. Hsu; M. A. Manzo

    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

  13. Mechanisms controlling the global oceanic distribution of the inert gases argon, nitrogen and neon

    Microsoft Academic Search

    Roberta C. Hamme; Steven R. Emerson

    2002-01-01

    Dissolved inert gas measurements in the ocean yield important information about processes that occur during water mass formation. We present argon, nitrogen, and neon data from the subtropical and subpolar North Pacific and the subtropical North Atlantic. All three gases were supersaturated at the surface. In the deep ocean, Ar and N2 were undersaturated while Ne re- mained supersaturated. All

  14. Isotope dilution analysis of polychlorinated biphenyls (PCBs) in transformer oil and global commercial PCB formulations by high resolution gas chromatography–high resolution mass spectrometry

    Microsoft Academic Search

    Takumi Takasuga; Kurunthachalam Senthilkumar; Tohru Matsumura; Ken Shiozaki; Shin-ichi Sakai

    2006-01-01

    Special polychlorinated biphenyls (PCBs) standards (native and isotope labeled) were analyzed by isotope dilution method using HRGC–HRMS. Multiple analysis of special PCBs standards by three different laboratories produced the relative response factors (RRFs) and relative standard deviations (RSDs %) was in the average of 0.979 and 3.86, respectively. Additionally, inter-laboratory analysis of various forms of transformer oil revealed the PCBs

  15. Microfluidic serial dilution ladder.

    PubMed

    Ahrar, Siavash; Hwang, Michelle; Duncan, Philip N; Hui, Elliot E

    2014-01-01

    Serial dilution is a fundamental procedure that is common to a large number of laboratory protocols. Automation of serial dilution is thus a valuable component for lab-on-a-chip systems. While a handful of different microfluidic strategies for serial dilution have been reported, approaches based on continuous flow mixing inherently consume larger amounts of sample volume and chip real estate. We employ valve-driven circulatory mixing to address these issues and also introduce a novel device structure to store each stage of the dilution process. The dilution strategy is based on sequentially mixing the rungs of a ladder structure. We demonstrate a 7-stage series of 1?:?1 dilutions with R(2) equal to 0.995 in an active device area of 1 cm(2). PMID:24231765

  16. The mathematics of dilution.

    PubMed

    Chatterjee, Barun Kumar

    2014-04-01

    The major objection to homeopathic medicine is that the doses of medicine prescribed in some cases are too dilute for any active ingredient to be present. The medicines would hence be rendered inactive, necessitating novel explanations for the action. A further examination of dilution in the light of the Langmuir equation shows that homeopathic medicines may not be as dilute as a simplistic application of Avogadro's Principle suggests, due to surface effects. PMID:24685420

  17. Simulations of Autoignition and Laminar Premixed Flames in Methane/Air Mixtures Diluted with Hot Products

    E-print Network

    Sidey, J.; Mastorakos, E.; Gordon, R. L.

    2014-04-23

    context. De Joannon et al. [6] continued investigating diluted counterflow diffusion flames and commented on MILD chemistry, concluding that reactant dilution with an inert species slows down oxidative chemical kinetics and increases the distance... ) that at the exit the hot gases were virtually in chemical equilibrium at the adiabatic flame temperature. These are called ``hot products” in this paper. (Note that a chemical equilibrium solver could have been used for defining this state, but the differences...

  18. Pressure Effect of Various Inert Gases on the Phase Behavior of Polystyrene-block-Poly(n-pentyl methacrylate) Copolymer

    NASA Astrophysics Data System (ADS)

    Moon, Hong Chul; Kim, Hye Jeong; Cho, Junhan; Kim, Jin Kon

    2013-03-01

    We investigated the pressure effect of three inert gases (nitrogen, helium and argon) on the phase behavior of polystyrene-block-poly(n-pentylmethacrylate) copolymer (PS-b-PnPMA) showing closed-loop phase behavior and baroplasticity. Helium gas pressure enhanced the miscibility between PS and PnPMA blocks similar to the hydrostatic pressure. Very interestingly, however, with increasing nitrogen and argon gas pressure, the miscibility between the two blocks decreased even though these two are also considered as inert gases. To explain these unexpected results, we measured the amount of gas absorption into each block. The experimentally measured gas absorption results are consistent with the theoretical ones based on the Sanchez-Lacombe theory. The results in this study imply that well-known and widely employed inert gases such as nitrogen and argon could significantly affect the phase behavior of a weakly interacting block copolymer at high pressures.

  19. Isotope dilution mass spectrometry

    NASA Astrophysics Data System (ADS)

    Heumann, Klaus G.

    1992-09-01

    In the past isotope dilution mass spectrometry (IDMS) has usually been applied using the formation of positive thermal ions of metals. Especially in calibrating other analytical methods and for the certification of standard reference materials this type of IDMS became a routine method. Today, the progress in this field lies in the determination of ultra trace amounts of elements, e.g. of heavy metals in Antarctic ice and in aerosols in remote areas down to the sub-pg g-1 and sub-pg m-3 levels respectively, in the analysis of uranium and thorium at concentrations of a few pg g-1 in sputter targets for the production of micro- electronic devices or in the determination of sub-picogram amounts of230Th in corals for geochemical age determinations and of226Ra in rock samples. During the last few years negative thermal ionization IDMS has become a frequently used method. The determination of very small amounts of selenium and technetium as well as of other transition metals such as vanadium, chromium, molybdenum and tungsten are important examples in this field. Also the measurement of silicon in connection with a re-determination of Avogadro's number and osmium analyses for geological age determinations by the Re/Os method are of special interest. Inductively-coupled plasma mass spectrometry is increasingly being used for multi-element analyses by the isotope dilution technique. Determinations of heavy metals in samples of marine origin are representative examples for this type of multi-element analysis by IDMS. Gas chromatography-mass spectrometry systems have also been successfully applied after chelation of metals (for example Pt determination in clinical samples) or for the determination of volatile element species in the environment, e.g. dimethyl sulfide. However, IDMS--specially at low concentration levels in the environment--seems likely to be one of the most powerful analytical methods for speciation in the future. This has been shown, up to now, for species of iodine, selenium and some heavy metals in aquatic systems.

  20. Reactivity of methane in nonthermal plasma in the presence of oxygen and inert gases at atmospheric pressure

    Microsoft Academic Search

    Mamoru Okumoto; Hyun Ha Kim; Kazunori Takashima; Shinji Katsura; Akira Mizuno

    2001-01-01

    Partial oxidation of methane to methanol and formaldehyde as liquid fuels with oxygen diluted with inert gases was investigated experimentally using the pulsed discharge plasma method under conditions of room temperature and atmospheric pressure. The experimental results indicated that ethylene (C2H4), ethane (C2 H6), methanol (CH3OH), formaldehyde (HCHO), hydrogen (H2), water (H2O), carbon monoxide (CO), and carbon dioxide (CO2) were

  1. Report on the source of the electrochemical impedance on cermet inert anodes

    SciTech Connect

    Windisch, C.F. Jr.; Stice, N.D.

    1991-02-01

    the Inert Electrode Program at Pacific Northwest Laboratory (PNL) is supported by the Office of Industrial Processes of the US Department of Energy and is aimed at improving the energy efficiency of Hall-Heroult cells through the development of inert anodes. The inert anodes currently under study are composed of a cermet material of the general composition NiO-NiFe{sub 2}O{sub 4}-Cu. The program has three primary objectives: (a) to evaluate the anode material in a scaled-up, pilot cell facility, (b) to investigate the mechanisms of the electrochemical reactions at the anode surface, and (c) to develop sensors for monitoring anode and/or electrolyte conditions. This report covers the results of a portion of the studies on anode reaction mechanisms. The electrochemical impedances of cermet inert anodes in alumina-saturated molten cryolite as a function of frequency, current density, and time indicated that a significant component of the impedance is due to the gas bubbles produced at the anode during electrolysis. The data also showed a connection between surface structure and impedance that appears to be related to the effects of surface structure on bubble flow. Given the results of this work, it is doubtful that a resistive film contributes significantly to the electrochemical impedances on inert anodes. Properties previously assigned to such a film are more likely due to the bubbles and those factors that affect the properties and dynamics of the bubbles at the anode surface. 12 refs., 16 figs., 3 tabs.

  2. The lateral stability of train suspension systems employing inerters

    Microsoft Academic Search

    Fu-Cheng Wang; Min-Kai Liao

    2010-01-01

    This paper investigates the benefits of lateral stability of train suspension systems employing a newly developed mechanical network element known as an inerter. An inerter was proposed as an ideal mechanical two-port element to substitute for the mass element in the mechanical\\/electrical analogy. As of now, inerters have been successfully applied to car and motorcycle suspension systems, for which significant

  3. Inerter Nonlinearities and the Impact on Suspension Control

    Microsoft Academic Search

    Fu-Cheng Wang; Wei-Jiun Su

    2008-01-01

    This paper discusses the nonlinear properties of Inerters and their impact on vehicle suspension control. The Inerter was recently introduced as an ideal mechanical two-terminal element which is a substitute for the mass element with the applied force proportional to the relative acceleration across the terminals. Until now, ideal Inerters have been applied to car, motorcycle and train suspension systems,

  4. Impact of inerter nonlinearities on vehicle suspension control

    Microsoft Academic Search

    Fu-Cheng Wang; Wei-Jiun Su

    2008-01-01

    This paper discusses the nonlinear properties of inerters and their impact on vehicle suspension control. The inerter was recently introduced as an ideal mechanical two-terminal element, which is a substitute for the mass element, where the applied force is proportional to the relative acceleration across the terminals. Until now, ideal inerters have been applied to vehicle, motorcycle and train suspension

  5. Performance analyses of building suspension control with inerters

    Microsoft Academic Search

    Fu-Cheng Wang; Cheng-Wei Chen; Min-Kai Liao; Min-Feng Hong

    2007-01-01

    This paper discusses the application of a new mechanical element, called inerter, to building suspension control. The inerter was proposed as a real two-terminal mechanical element, which is a substitute for the mass element, with the applied force proportional to the relative acceleration across two terminals. To investigate the performance benefits of building suspension with inerters, three building models were

  6. 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

  7. Polyvinyl alcohol battery separator containing inert filler

    NASA Astrophysics Data System (ADS)

    Sheibley, D. W.; Hsu, L. C.; Manzo, M. A.

    1981-06-01

    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.

  8. Polyvinyl alcohol battery separator containing inert filler

    SciTech Connect

    Sheibley, D.W.; Hsu, L.C.; Manzo, M.A.

    1981-06-01

    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 enhences 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.

  9. Isotope dilution analysis of polychlorinated biphenyls (PCBs) in transformer oil and global commercial PCB formulations by high resolution gas chromatography-high resolution mass spectrometry.

    PubMed

    Takasuga, Takumi; Senthilkumar, Kurunthachalam; Matsumura, Tohru; Shiozaki, Ken; Sakai, Shin-ichi

    2006-01-01

    Special polychlorinated biphenyls (PCBs) standards (native and isotope labeled) were analyzed by isotope dilution method using HRGC-HRMS. Multiple analysis of special PCBs standards by three different laboratories produced the relative response factors (RRFs) and relative standard deviations (RSDs %) was in the average of 0.979 and 3.86, respectively. Additionally, inter-laboratory analysis of various forms of transformer oil revealed the PCBs concentrations were in the following order; PCBs fortified transformer oil (940-1300 ng/g)>PCB polluted transformer oil (490-680 ng/g)>chemically degraded-transformer oil (480-490 ng/g) and PCBs free oil (ND-17 ng/g). Chemical degradation resulted in an order of magnitude decrease in the PCB concentrations. Specifically, higher chlorinated PCBs degraded into lower chlorinated PCBs. Also, composition of PCBs have been determined in PCB formulations from Japan (Kanechlor), Germany (Clophen), USA (Aroclor), Russia (Sovol) and Poland (Chlorofen). Major PCBs (24-PCB congeners) contributed 54-67%, 55-68%, 16-69%, 71% and 72% in Kanechlor, Clophen, Aroclor, Sovol and Chlorofen, respectively to total PCBs. The homologue pattern of Kanechlor, Aroclor and Clophen in technical fromulation was similar (e.g., Kanechlor-300 resembled to those of Clophen A-30 and Aroclor-1242). Furthermore, congener-specific distributions of major PCBs/dioxin-like PCBs and toxic equivalency quantities (TEQ) were calculated. Based on our tentative assumption calculations, cumulative production of five different technical PCB formulations, WHO-TEQ emission was estimated to be approximately 16.05 tons. PMID:15946725

  10. 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).)

  11. Optimisation of the analytical method for octa-, nona- and deca-brominated diphenyl ethers using gas chromatography–quadrupole mass spectrometry and isotope dilution

    Microsoft Academic Search

    Akifumi Eguchi; Tomohiko Isobe; Karri Ramu; Shinsuke Tanabe

    2011-01-01

    An analytical method for higher brominated congeners of polybrominated diphenyl ethers (PBDEs) was optimised using a gas chromatograph equipped with an electron impact ionisation-quadrupole mass spectrometer (GC-EI-qMS) and five native PBDEs and three C12-labelled congeners in biological and environmental samples (mussels, sediment, dust). In the optimised instrumental conditions, abundance and repeatability improved with increase in temperature of the ion source.

  12. Resonance-inert stabilization for space stations

    NASA Technical Reports Server (NTRS)

    Vonpragenau, G. L.

    1972-01-01

    An approach to stabilizing control systems is presented which structures controllers like passive mechanical systems. The controller is visualized as a structural part with a passive behavior similar to springs, dashpots, and masses. If such a controller is connected by a proper feedback arrangement, then a passive mechanical plant cannot upset stability, regardless of masses, resonances, and three-dimensional coupling. The concept of resonance-inert stabilization is explained by structuring the controller of a simple feedback loop. Reactive functions, connections, and matrices are defined and used in the stabilization concept. The realization of a possible Skylab control system is discussed and compared with the present design. This example demonstrates the applicability to three-dimensional problems with lagging controllers.

  13. Inert anodes and advanced smelting of aluminum

    SciTech Connect

    ASME Technical Working Group on Inert Anode Technologies

    1999-07-01

    This 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 issued associated with these technologies from a technical, environmental, and economic viewpoint. It discusses the outlook for the direct retrofit of advanced reduction technologies to existing aluminum smelters, and compares retrofits to ''brown field'' usage and ''green field'' adoption of the technologies. A number of observations and recommendations are offered for consideration concerning further research and development efforts that may be directed toward these advanced technologies. The opportunities are discussed in the context of incremental progress that is being made in conventional Hall-Heroult cell systems.

  14. Dark matter in inert triplet models

    SciTech Connect

    Araki, Takeshi [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Geng, C. Q. [Department of Physics, National Tsing Hua University, Hsinchu, Taiwan 300 (China); National Center for Theoretical Sciences, Hsinchu, Taiwan 300 (China); Nagao, Keiko I. [Department of Physics, National Tsing Hua University, Hsinchu, Taiwan 300 (China)

    2011-04-01

    We study the inert triplet models, in which the standard model is extended to have a new SU(2){sub L} triplet scalar (Y=0 or 2) with an Z{sub 2} symmetry. We show that the neutral component of the triplet can be a good dark matter candidate. In particular, for the hypercharge Y=0 triplet model, the WMAP data favors the region where the dark matter mass is around 5.5 TeV, which is also consistent with the direct detection experiments. In contrast, for the Y=2 model, although dark matter with its mass around 2.8 TeV is allowed by WMAP, it is excluded by the direct detection experiments because the spin-independent cross section is enhanced by the Z-mediated tree-level scattering process.

  15. Dilution, Concentration, and Flotation

    ERIC Educational Resources Information Center

    Liang, Ling; Schmuckler, Joseph S.

    2004-01-01

    As both classroom teaching practice and literature show, many students have difficulties learning science concepts such as density. Here are some investigations that identify the relationship between density and floating through experimenting with successive dilution of a liquid, or the systematic change of concentration of a saltwater solution.…

  16. 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.

  17. A compact rotating dilution refrigerator

    E-print Network

    Fear, M J; Chorlton, D A; Zmeev, D E; Gillott, S J; Sellers, M C; Richardson, P P; Agrawal, H; Batey, G; Golov, A I

    2013-01-01

    We describe the design and performance of a new rotating dilution refrigerator that will primarily be used for investigating the dynamics of quantized vortices in superfluid 4He. All equipment required to operate the refrigerator and perform experimental measurements is mounted on two synchronously driven, but mechanically decoupled, rotating carousels. The design allows for relative simplicity of operation and maintenance and occupies a minimal amount of space in the laboratory. Only two connections between the laboratory and rotating frames are required for the transmission of electrical power and helium gas recovery. Measurements on the stability of rotation show that rotation is smooth to around 0.001 rad/s up to angular velocities in excess of 2.5 rad/s. The behavior of a high-Q mechanical resonator during rapid changes in rotation has also been investigated.

  18. 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.

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

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...TANK VESSELS CARRYING OIL IN BULK Crude Oil Washing (COW) System on Tank Vessels... (1) Before each cargo tank is crude oil washed, the oxygen content in the...cargo tank with partial bulkheads is crude oil washed, each area of that...

  20. Neuroprotective and neurotoxic properties of the 'inert' gas, xenon

    Microsoft Academic Search

    D. Ma; S. Wilhelm; M. Maze; N. P. Franks

    2002-01-01

    Background. Antagonists of the N-methyl-D-aspartate (NMDA) subtype of glutamate recep- tors have been shown not only to have neuroprotective effects but also to exhibit neurotoxic properties. In this study, we used c-Fos, a protein product of an immediate early gene, as a marker of neuronal injury to compare the neuroprotective effects of xenon and the neurotoxic properties of xenon, nitrous

  1. Studying Flammability in a Commercial Transport Fuel Tank with Inerting

    Microsoft Academic Search

    William M. Cavage; Steven M. Summer; Robert I. Ochs; C. E. Polymeropoulos

    2005-01-01

    As part of the continued emphasis on fuel tank safety, the Federal Aviation Administration (FAA) has developed a demonstration fuel tank inerting system and has tested it on a NASA -operated Boeing 747 aircraft. To support this, the FAA developed two models to predict both fuel tank oxygen concentration and flammability in an inerted ullage, based on pre viously developed

  2. 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.

  3. 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.

  4. 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}.

  5. Optimization of an isotope dilution gas chromatography/mass spectrometry method for the detection of endogenous estrogen metabolites in urine samples.

    PubMed

    Knust, Ulrike; Strowitzki, Thomas; Spiegelhalder, Bertold; Bartsch, Helmut; Owen, Robert Wyn

    2007-01-01

    A gas chromatography/mass spectrometry (GC/MS) method for the simultaneous quantitation of ten estrogen metabolites in human urine was optimized. The method consists of initial enzymatic hydrolysis of the estrogen conjugates using beta-glucuronidase followed by solid-phase extraction (SPE) on Sep-pak C18 columns and further sample purification by ion-exchange chromatography on QAE-Sephadex cartridges in the acetate form. QAE-Sephadex cartridges in the borate form were used to separate estrogens into two fractions: one fraction containing estrogens lacking vicinal cis-hydroxyls (Fr 1) and another containing estrogens possessing vicinal cis-hydroxyls (catecholestrogens; Fr 2). Finally, following O-trimethylsilyl ether derivatization, the estrogens were analyzed by GC/MS in the selected ion monitoring mode. Estrogens were quantitated using deuterated internal standards, which were added to the samples at the initiation of the work-up procedures. After addition to estrogen-low male human samples the standards showed good chromatographic linear response and reproducibility. A reduction in the number of steps and improvements in the robustness of the work-up procedures were achieved. The modified method described is less complex, amenable to use with commercially available SPE columns and fulfils all the reliability criteria, resulting in highly specific and accurate results. PMID:17569095

  6. Fast and solvent-free quantitation of boar taint odorants in pig fat by stable isotope dilution analysis-dynamic headspace-thermal desorption-gas chromatography/time-of-flight mass spectrometry.

    PubMed

    Fischer, Jochen; Haas, Torsten; Leppert, Jan; Lammers, Peter Schulze; Horner, Gerhard; Wüst, Matthias; Boeker, Peter

    2014-09-01

    Boar taint is a specific off-odour of boar meat products, known to be caused by at least three unpleasant odorants, with very low odour thresholds. Androstenone is a boar pheromone produced in the testes, whereas skatole and indole originate from the microbial breakdown of tryptophan in the intestinal tract. A new procedure, applying stable isotope dilution analysis (SIDA) and dynamic headspace-thermal desorption-gas chromatography/time-of-flight mass spectrometry (dynHS-TD-GC/TOFMS) for the simultaneous quantitation of these boar taint compounds in pig fat was elaborated and validated in this paper. The new method is characterised by a simple and solvent-free dynamic headspace sampling. The deuterated compounds d3-androstenone, d3-skatole and d6-indole were used as internal standards to eliminate matrix effects. The method validation performed revealed low limits of detection (LOD) and quantitation (LOQ) with high accuracy and precision, thus confirming the feasibility of the new dynHS-TD-GC/TOFMS approach for routine analysis. PMID:24731353

  7. Behavior of Fission Products in YSZ-Based Inert Matrix Fuel

    SciTech Connect

    Wang, L.M.; Zhu, S.; Ewing, R.C.

    2001-06-17

    Pu disposal has led to increased interest in the possibility of ''burning'' actinides in inert-matrix fuels. Yttria-stabilized cubic zirconia (YSZ) is a promising candidate material. The effects of fission product incorporation on the microstructure of YSZ (with 9.5 mol% of yttria) were investigated by ion implantation (using 70- to 440-keV Cs{sup +}, Sr{sup +}, and I{sup +} ions) and transmission electron microscopy (TEM) in order to evaluate the material's performance as both an inert fuel matrix and a nuclear waste form. It was found that incorporation of an excess amount of cesium (>8 at.%) at room temperature causes amorphization of the cubic zirconia structure, which may lead to a higher leaching rate in the waste repository. On the other hand, iodine and strontium precipitate out in gas bubbles or secondary phases, respectively, at elevated temperature, leading to a lower release rate of the radionuclides.

  8. Distribution of inert gases in fines from the Cayley-Descartes region

    NASA Technical Reports Server (NTRS)

    Walton, J. R.; Lakatos, S.; Heymann, D.

    1973-01-01

    The inert gases in 14 different fines and in one sample of 2 to 4 mm fines from Apollo 16 were measured by mass spectroscopy with respect to trapped solar wind gases, cosmogenic gases, and 'parentless' Ar-40. Such studies are helpful for the understanding of regolith evolution, of transport of regolith fines, and of the lunar atmosphere. The Apollo 16 soils are unique because they represent, after Luna 20, the second and much more extensive record from the lunar highlands. The landing site presents the problem of materials from the Cayley Formation vs those from the Descartes Formation. There are two large, relatively fresh craters in the area, North Ray and South Ray, whose ejecta patterns may be recognized in the inert-gas record.

  9. 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.

  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. Improved Back-Side Purge-Gas Chambers For Plasma Arc Welding

    NASA Technical Reports Server (NTRS)

    Ezell, Kenneth G.; Mcgee, William F.; Rybicki, Daniel J.

    1995-01-01

    Improved chambers for inert-gas purging of back sides of workpieces during plasma arc welding in keyhole (full-penetration) mode based on concept of directing flows of inert gases toward, and concentrating them on, hot weld zones. Tapered chamber concentrates flow of inert gas on plasma arc plume and surrounding metal.

  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. 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...

  14. 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...

  15. 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...

  16. 75 FR 7560 - Public Availability of Identities of Inert Ingredients in Pesticides; Extension of Comment Period

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-22

    ...FRL-8813-3] Public Availability of Identities of Inert Ingredients in Pesticides...increase public availability of the identities of the inert ingredients in pesticide...increase public availability of the identities of the inert ingredients in...

  17. 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.

  18. 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.

  19. Gas shielding apparatus

    DOEpatents

    Brandt, Daniel (Los Alamos, NM)

    1985-01-01

    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.

  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. Results from electrolysis test of a prototype inert anode: Inert Electrode Program

    SciTech Connect

    Strachan, D.M.; Windisch, C.F. Jr.; Koski, O.H.; Morgan, L.G. (Pacific Northwest Lab., Richland, WA (USA)); Peterson, R.D.; Richards, N.E.; Tabereaux, A.T. (Reynolds Metals Co., Sheffield, AL (USA). Mfg. Technology Lab.)

    1990-05-01

    Nonconsumable or inert anodes are being developed at the Pacific Northwest Laboratory (PNL)({sup a}) for use in the electrolytic production of aluminum. A series of laboratory test on the laboratory scale (Hart et al. 1987; Strachan et al. 1989; Marschman 1989) has shown the technology to be potentially feasible. A series of larger-scale experiments are now being run to determine the viability of the technology on a commercial scale. The results reported here are from a test performed at the Reynolds Metals Company, Manufacturing Technology Laboratory, Sheffield, Alabama, using a prototype anode. The prototype anode was approximately 15 cm in diameter and 20 cm high (Figure 1.1). The objectives of the test were to determine if an anode, produced by a commercial vendor, could survive in a test under conditions approximating those found in a commercial electrolysis cell; to familiarize the Reynolds staff with the operation of such an anode in a subsequent pilot cell test of the inert anode technology; and to familiarize the PNL staff with the operations at the Reynolds Metals Company facility. 8 refs., 39 figs., 9 tabs.

  2. He dilution refrigerator

    NASA Astrophysics Data System (ADS)

    Jessen, F.; Knufinke, M.; Bell, S. C.; Vergien, P.; Hattermann, H.; Weiss, P.; Rudolph, M.; Reinschmidt, M.; Meyer, K.; Gaber, T.; Cano, D.; Günther, A.; Bernon, S.; Koelle, D.; Kleiner, R.; Fortágh, J.

    2014-09-01

    We describe the preparation of ultracold atomic clouds in a dilution refrigerator. The closed-cycle 3He/4He cryostat was custom made to provide optical access for laser cooling, optical manipulation and detection of atoms. We show that the cryostat meets the requirements for cold atom experiments, specifically in terms of operating a magneto-optical trap, magnetic traps and magnetic transport under ultrahigh vacuum conditions. The presented system is a step toward the creation of a quantum hybrid system combining ultracold atoms and solid-state quantum devices.

  3. 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.

  4. Dispersion serial dilution methods using the gradient diluter device.

    PubMed

    Walling, Leslie; Schulz, Craig; Johnson, Michael

    2012-12-01

    A solute aspirated into a prefilled tube of diluent undergoes a dilution effect known as dispersion. Traditionally the effects of dispersion have been considered a negative consequence of using liquid-filled fixed-tip liquid handlers. We present a novel device and technique that utilizes the effects of dispersion to the benefit of making dilutions. The device known as the Gradient Diluter extends the dilution range of practical serial dilutions to six orders of magnitude in final volumes as low as 10??L. Presented are the device, dispersion methods, and validation tests using fluorescence detection of sulforhodamine and the high-performance liquid chromatography/ultraviolet detection of furosemide. In addition, a T-cell inhibition assay of a relevant downstream protein is used to demonstrate IC(50) curves made with the Gradient Diluter compare favorably with those generated by hand. PMID:22364546

  5. Effects of dilution on vehicle emissions of primary particles

    NASA Astrophysics Data System (ADS)

    Hayden, K. L.; Li, S.; Liggio, G.; McCurdy, M.; Chan, T.; Rostkowski, J.

    2009-12-01

    Dilution of primary aerosols from vehicles into the ambient atmosphere can change their physical and chemical characteristics. In order to study these processes, experiments were conducted in an engine testing facility at Environment Canada in Ottawa, Ontario. Exhaust from a light duty diesel engine was vented into a constant volume sampling (CVS) system where it underwent primary dilution at an ambient temperature of 25oC, leading to a primary dilution ratio of 10-15. From the CVS, the exhaust was further diluted using a combination of a Dekati ejection diluter and mixing with zero air in a flow tube, achieving secondary dilution ratios of up to 3000. Particle and gas measurements were made through multi-ports in the CVS and the flow tube using an SMPS, FMPS, AMS, and SP2, and instruments to measure CO, CO2, NOx, and total hydrocarbons (THC). Preliminary results indicate that regardless of dilution ratios, primary particles contain significant amounts of organic material that appear to reside on small black carbon cores. With increasing dilution ratios, the primary particle sizes become progressively smaller, suggesting volatilization of the adsorbed organic material. Results from various engine operating modes (simulating different driving conditions) will be presented.

  6. The inert doublet model of dark matter revisited

    Microsoft Academic Search

    Laura Lopez Honorez; Carlos E. Yaguna

    2010-01-01

    The inert doublet model, a minimal extension of the Standard Model by a second higgs doublet with no direct couplings to quarks\\u000a or leptons, is one of the simplest scenarios that can explain the dark matter. In this paper, we study in detail the impact\\u000a of dark matter annihilation into the three-body final state on the phenomenology of the inert

  7. 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.

  8. 46 CFR 153.964 - Discharge by gas pressurization.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...not authorize cargo discharge by gas pressurization unless: ...or a nonflammable, nontoxic gas inert to the cargo; and ...tank; or (2) For an inert gas medium: (i) A safety relief valve with a cross sectional flow area at least equal to that of...

  9. Extractive stripping of inert-rich hydrocarbon gases with a preferential physical solvent

    SciTech Connect

    Mehra, Y.R.

    1987-07-14

    A process is described for treating a natural gas stream containing methane, heavier hydrocarbons, and an inert gas, an improvement comprising: selectivity extracting natural gas liquids from the natural gas stream with a preferential physical solvent which provides selective capability for recovery according to the selected degree of: (a) ethane in amounts ranging from 2-98%, (b) propane in amounts ranging from 2-99%, (c) butanes in amounts ranging from 2-100%, or (d) pentanes and higher molecular weight hydrocarbons in amounts ranging up to 100%, the improvement comprising the following steps: A. selecting the preferential physical solvent which is selective for ethane and heavier hydrocarbon components of the gas stream such that: (1) relative volatility of methane over ethane is at least 5.0 and the hydrocarbon loading capacity, defined as solubility of ethane in the solvent, is at least 0.25 standard cubic feet of ethane per gallon of the solvent, or (2) the preferential factor, determined by the multiplication of relative volatility of methane over ethane by the solubility of ethane in solvent, in standard cubic feet of ethane per gallon of solvent, is at least 1.25; B. selectively extracting and stripping the natural gas stream with the physical solvent to produce an inert gas stream and a rich solvent stream containing methane and the hydrocarbons heavier than methane; and C. distilling the rich solvent stream to produce a stream vent to form a solution having a molar ratio of silicon alkoxide to water in the range of about 1 to about 10.

  10. Irreversibility in diluted antiferromagnets

    SciTech Connect

    Soukoulis, C.M.; Grest, G.S.; Ro, C.; Levin, K.

    1985-04-15

    We compute the irreversibility phase diagram, and history-dependent magnetizations for diluted Ising antiferromagnets in three dimensions. We use an iterative mean-field technique which has proved quite successful for treating spin glasses. Motion of the domain walls as the magnetic field is varied at low temperature is also discussed. The onset of time-dependent long-range order and magnetization anomalies are predicted for certain regions of the H-T phase diagram from our studies of the free-energy surface. Our results are compared to those of the random field ferromagnet and spin glasses, which have the common feature that on the time scale of a physical measurement the system is trapped in a local minimum of the free-energy surface. Irreversibility then results primarily from the disappearance of a given minimum as the field or temperature are changed and not from tunneling or thermal activation processes.

  11. Dilute magnetic topological semiconductors

    NASA Astrophysics Data System (ADS)

    Kim, Kyoung-Min; Jho, Yong-Soo; Kim, Ki-Seok

    2015-03-01

    Replacing semiconductors with topological insulators, we propose the problem of dilute magnetic topological semiconductors. Performing the renormalization group analysis for an effective field theory, where doped magnetic impurities give rise to a spatially modulated random axion term, we find a novel insulator-metal transition from either a topological or band insulating phase to an inhomogeneously distributed Weyl metallic state with such insulating islands, where extremely broad distributions of ferromagnetic clusters combined with strong spin-orbit interactions are responsible for the emergence of randomly distributed Weyl metallic islands. Since electromagnetic properties in a Weyl metal are described by axion electrodynamics, the role of random axion electrodynamics in transport phenomena casts an interesting problem beyond the physics of percolation in conventional disorder-driven metal-insulator transitions.

  12. Standard dilution analysis.

    PubMed

    Jones, Willis B; Donati, George L; Calloway, Clifton P; Jones, Bradley T

    2015-02-17

    Standard dilution analysis (SDA) is a novel calibration method that may be applied to most instrumental techniques that will accept liquid samples and are capable of monitoring two wavelengths simultaneously. It combines the traditional methods of standard additions and internal standards. Therefore, it simultaneously corrects for matrix effects and for fluctuations due to changes in sample size, orientation, or instrumental parameters. SDA requires only 200 s per sample with inductively coupled plasma optical emission spectrometry (ICP OES). Neither the preparation of a series of standard solutions nor the construction of a universal calibration graph is required. The analysis is performed by combining two solutions in a single container: the first containing 50% sample and 50% standard mixture; the second containing 50% sample and 50% solvent. Data are collected in real time as the first solution is diluted by the second one. The results are used to prepare a plot of the analyte-to-internal standard signal ratio on the y-axis versus the inverse of the internal standard concentration on the x-axis. The analyte concentration in the sample is determined from the ratio of the slope and intercept of that plot. The method has been applied to the determination of FD&C dye Blue No. 1 in mouthwash by molecular absorption spectrometry and to the determination of eight metals in mouthwash, wine, cola, nitric acid, and water by ICP OES. Both the accuracy and precision for SDA are better than those observed for the external calibration, standard additions, and internal standard methods using ICP OES. PMID:25599250

  13. Bicosomes: Bicelles in Dilute Systems

    Microsoft Academic Search

    Gelen Rodríguez; Guadalupe Soria; Elisenda Coll; Laia Rubio; Lucyanna Barbosa-Barros; Carmen López-Iglesias; Anna M. Planas; Joan Estelrich; Alfons de la Maza; Olga López

    2010-01-01

    Bicelles are discoidal phospholipid nanostructures at high lipid concentrations. Under dilute conditions, bicelles become larger and adopt a variety of morphologies. This work proposes a strategy to preserve the discoidal morphology of bicelles in environments with high water content. Bicelles were formed in concentrated conditions and subsequently encapsulated in liposomes. Later dilution of these new structures, called bicosomes, demonstrated that

  14. Zirconia-magnesia inert matrix fuel and waste form: Synthesis, characterization and chemical performance in an advanced fuel cycle

    NASA Astrophysics Data System (ADS)

    Holliday, Kiel Steven

    There is a significant buildup in plutonium stockpiles throughout the world, because of spent nuclear fuel and the dismantling of weapons. The radiotoxicity of this material and proliferation risk has led to a desire for destroying excess plutonium. To do this effectively, it must be fissioned in a reactor as part of a uranium free fuel to eliminate the generation of more plutonium. This requires an inert matrix to volumetrically dilute the fissile plutonium. Zirconia-magnesia dual phase ceramic has been demonstrated to be a favorable material for this task. It is neutron transparent, zirconia is chemically robust, magnesia has good thermal conductivity and the ceramic has been calculated to conform to current economic and safety standards. This dissertation contributes to the knowledge of zirconia-magnesia as an inert matrix fuel to establish behavior of the material containing a fissile component. First, the zirconia-magnesia inert matrix is synthesized in a dual phase ceramic containing a fissile component and a burnable poison. The chemical constitution of the ceramic is then determined. Next, the material performance is assessed under conditions relevant to an advanced fuel cycle. Reactor conditions were assessed with high temperature, high pressure water. Various acid solutions were used in an effort to dissolve the material for reprocessing. The ceramic was also tested as a waste form under environmental conditions, should it go directly to a repository as a spent fuel. The applicability of zirconia-magnesia as an inert matrix fuel and waste form was tested and found to be a promising material for such applications.

  15. 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.

  16. 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.

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  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. 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.

  3. Sea Urchin Embryology: Sperm Dilution

    NSDL National Science Digital Library

    PhD David Epel (Stanford U. Hopkins Marine Station)

    2007-04-20

    Lab directions for up to two 50 min periods and the last of the dilution labs. Includes set up information, materials, procedure, experimental design, things to observe, math possibilities, thought-provoking questions and an assessment.

  4. 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.

  5. Constraints on inert dark matter from metastability of electroweak vacuum

    E-print Network

    Khan, Najimuddin

    2015-01-01

    Inert scalar doublet model of dark matter can be valid upto the Planck scale. We briefly review the bounds on the model in such a scenario and identify parameter spaces that lead to absolute stability and metastability of the electroweak vacuum.

  6. Dark matter with two inert doublets plus one Higgs doublet

    NASA Astrophysics Data System (ADS)

    Keus, Venus; King, Stephen F.; Moretti, Stefano; Sokolowska, Dorota

    2014-11-01

    Following the discovery of a Higgs boson, there has been renewed interest in the general 2-Higgs-Doublet Model (2HDM). A model with One Inert Doublet plus One Higgs Doublet (I(1+1)HDM), where one of the scalar doublets is "inert" (since it has no vacuum expectation value and does not couple to fermions) has an advantage over the 2HDM since it provides a good Dark Matter (DM) candidate, namely the lightest inert scalar. Motivated by the existence of three fermion families, here we consider a model with two scalar doublets plus one Higgs doublet (I(2+1)HDM), where the two scalar doublets are inert. The I(2+1)HDM has a richer phenomenology than either the I(1+1)HDM or the 2HDM. We discuss the new regions of DM relic density in the I(2+1)HDM with simplified couplings and address the possibility of constraining the model using recent results from the Large Hadron Collider (LHC) and DM direct detection experiments.

  7. Impedance Measurements of Inertance Tubes at High Frequency and Pressure

    NASA Astrophysics Data System (ADS)

    Lewis, M. A.; Taylor, R.; Bradley, P. E.; Radebaugh, R.; Grossman, G.; Gan, Z.

    2008-03-01

    Previously measured and calculated impedances of inertance tubes were compared at frequencies below 70 Hz and average pressures below 3 MPa. In this paper we present similar comparisons for frequencies up to 150 Hz and average pressures up to 3.5 MPa. Measurements were made on inertance tube diameters from 1.0 mm to about 3.0 mm, as well as on a double diameter arrangement. Pressure ratios were varied from 1.1 to 1.45, and acoustic powers were varied up to about 80 W. In these measurements the use of higher frequencies has the potential of reducing the size of both the pressure oscillator and the cold finger for a given refrigeration power. The smaller cold finger also leads to faster cool-down. In these experiments, flow at the entrance to the inertance tube was determined from measurements of the calibrated pressure drop through a transfer line from the compressor. The wide range of frequencies and acoustic powers covered in these measurements enable us to separate the effects of compliance and inertance in the comparisons with a transmission line model.

  8. Combustion of hydrocarbon fuels within porous inert media

    Microsoft Academic Search

    J. R. Howell; M. J. Hall; J. L. Ellzey

    1996-01-01

    There has been a recent surge of interest in the combustion of hydrocarbon fuels within porous inert media. The interest has been directed by the needs of industry to develop high performance radiant heaters while complying with increasingly stringent emissions regulations. This paper reviews the processes associated with non-catalytic combustion within porous media, and describes related experimental and modeling research.

  9. Significant Gamma Lines from Inert Higgs Dark Matter

    Microsoft Academic Search

    Michael Gustafsson; Erik Lundström; Lars Bergström; Joakim Edsjö

    2007-01-01

    One way to unambiguously confirm the existence of particle dark matter and determine its mass would be to detect its annihilation into monochromatic gamma-rays in upcoming telescopes. One of the most minimal models for dark matter is the inert doublet model, obtained by adding another Higgs doublet with no direct coupling to fermions. For a mass between 40 and 80

  10. 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 [Thin Film Physics Div., Department of Physics (IFM), Linkoeping University, SE-581 83 (Sweden); Institute of Technical Physics and Materials Science, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Konkoly Thege Miklos ut 29-33. H-1121 Budapest (Hungary); Thin Film Physics Div., Department of Physics (IFM), Linkoeping University, SE-581 83 (Sweden)

    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.

  11. Sea Urchin Embryology: Simple Dilutions

    NSDL National Science Digital Library

    PhD David Epel (Stanford U. Hopkins Marine Station)

    2006-12-20

    Starting from a known concentration students learn to use dilutions to determine the concentration of an unknown. The following skills are used in this lesson: 1. making dilutions 2. reading the meter on a simple homemade spectrophotometer 3. keeping careful laboratory records 4. graphing on linear graph paper 5. determining an unknown concentration from known 6. using a colored filter to enhance contrast and sensitivity

  12. All optical O2 sensors using innovative phase fluorimetry for monitoring of headspace in ullage for FAA mandated inerting fuel tanks of commercial airlines

    Microsoft Academic Search

    Allen Panahi

    2011-01-01

    This paper explores the design and development of an all optical O2 sensor system that can be used for monitoring of headspace gases in the ullage of inerting fuel tanks of commercial airplanes. Also included is detailed discussion of the various test and measurement techniques used to estimate the O2 gas concentration .We compare the various intensity based approaches and

  13. 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.

  14. 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.

  15. Perpendicular diffusion of a dilute beam of charged dust particles in a strongly coupled dusty plasma

    E-print Network

    Goree, John

    a significant quantity of neutral gas. Due to the large charge, a collection of dust particles can be stronglyPerpendicular diffusion of a dilute beam of charged dust particles in a strongly coupled dusty investigate the diffusion of a dilute beam of charged projectiles as they scatter on particles in a strongly

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

    Microsoft Academic Search

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

    2011-01-01

    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

  17. 46 CFR 194.15-17 - Compressed gases other than inert gases.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 false Compressed gases other than inert gases. 194.15-17 Section 194...AND OTHER HAZARDOUS MATERIALS Chemistry Laboratory and Scientific Laboratory § 194.15-17 Compressed gases other than inert gases....

  18. 46 CFR 194.15-17 - Compressed gases other than inert gases.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Compressed gases other than inert gases. 194.15-17 Section 194...AND OTHER HAZARDOUS MATERIALS Chemistry Laboratory and Scientific Laboratory § 194.15-17 Compressed gases other than inert gases....

  19. 46 CFR 194.15-17 - Compressed gases other than inert gases.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 false Compressed gases other than inert gases. 194.15-17 Section 194...AND OTHER HAZARDOUS MATERIALS Chemistry Laboratory and Scientific Laboratory § 194.15-17 Compressed gases other than inert gases....

  20. Advances towards the qualification of an aircraft fuel tank inert environment fiber optic oxygen sensor system

    NASA Astrophysics Data System (ADS)

    Mendoza, Edgar A.; Esterkin, Yan; Kempen, Cornelia; Sun, Songjian; Susko, Kenneth; Goglia, John

    2011-06-01

    An all optical pressure and temperature compensated fiber optic oxygen sensor (FOxSenseTM) system is under qualification for use in the in-situ closed-loop-control of the inert atmosphere environment inside fuel tanks of military and commercial aircraft. The all-optical oxygen environment control sensor is a passive, intrinsically safe, fiber-optic sensor device with no electrical connections leading to the sensors installed within the fuel tanks of an aircraft. To control the fuel tank environment, an array of multiple sensors is deployed throughout the fuel tanks of an aircraft, and a remote multi-channel optoelectronic system is used to monitor the status of all the sensors in real time to provide feedback oxygen environment information to the on-board inert gas generating system (OBIGS). Qualification testing of the all optical sensor have demonstrated the ability to monitor the oxygen environment inside a simulated fuel tank environment in the oxygen range from 0% to 21% oxygen concentrations, temperatures from (-) 40°C to (+) 60°C, and altitudes from sea level to 40,000 feet. Fiber optic oxygen sensors with built-in temperature compensation as well as the conduit fiber optic cables have passed DO-160E including acoustic noise and burn test.

  1. Inert matrix and thoria fuel irradiation at an international research reactor

    NASA Astrophysics Data System (ADS)

    Streit, M.; Tverberg, T.; Wiesenack, W.; Vettraino, F.

    2006-06-01

    A major issue in the public debate on nuclear power, is how to break down the large plutonium stockpiles. Different concepts have been developed during the last years to burn plutonium. Two such concepts are stabilised zirconia based inert matrix (IM) and thoria (T) fuels. By using of IM fuels a larger fraction of plutonium could potentially be consumed without breeding new plutonium in comparison with todays MOX fuels. The aim of the presented study is to measure the general thermal behaviour of IM, inert matrix doped with thoria (IMT) and thoria under irradiation conditions similar to those in current light water reactor (LWRs). Of particular interest are the fuel thermal conductivity (and its degradation with burnup), fission gas release (FGR), fuel densification and fuel swelling. The irradiation is performed under HBWR conditions and a target burnup of ˜400-450 kW d cm -3, which is equivalent to ˜40-45 MW d kg -1 for the MOX fuel, is envisaged. Among other things considerably higher operating temperatures in the IM and IMT rods have been observed compared with those in the thoria fuel. The higher temperatures, which were caused by the lower thermal conductivity of IM, result in higher FGR of the IM and IMT fuel. This work gives the obtained results after 6 cycles (671 days) of irradiation.

  2. Yttrium stabilised zirconia inert matrix fuel irradiation at an international research reactor

    NASA Astrophysics Data System (ADS)

    Streit, M.; Wiesenack, W.; Tverberg, T.; Hellwig, Ch.; Oberländer, B. C.

    2006-06-01

    Different concepts have been developed during the last decade to transmute transuranium elements (TRU) using uranium-free inert matrix fuels (IMF) in a once-through-cycle to reduce the amount of TRU in the nuclear waste. For today's LWRs yttrium stabilised zirconia (YSZ) and other oxides like alumina, spinel or ceria have been proposed as inert matrix materials. By employing IMF, a larger fraction of plutonium can potentially be consumed in comparison with MOX fuels without breeding new plutonium. The aim of the presented study is to measure the general thermal behaviour of YSZ-based IMF under irradiation conditions similar to those in current LWRs in direct comparison to standard MOX fuel. Of particular interest are the fuel thermal conductivity (and its degradation with burnup), fission gas release (FGR), fuel densification and fuel swelling. A secondary aim is the direct comparison of the fuel performance between YSZ-based IMF and MOX fuel. The irradiation is performed under HBWR conditions and has reached an average assembly burnup of ˜300 kW d cm -3 until the end of 2004, which is equivalent to ˜29 MW d kg -1 for the MOX fuel.

  3. 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)

  4. DEVELOPMENT OF SAMPLING METHODOLOGY FOR DILUTION AIR SAMPLING OF CONDENSIBLE EMISSIONS FROM STATIONARY SOURCES

    EPA Science Inventory

    This report describes the initial development of a technique using dilution of stack gas with conditioned ambient air for measurement of the particulate mass of condensible emissions from stationary sources. he methodology developed is designed for widespread application to measu...

  5. 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.

  6. A dynamical systems model of the limiting oxygen index test: II. Retardancy due to char formation and addition of inert fillers

    NASA Astrophysics Data System (ADS)

    Nelson, M. I.

    2001-03-01

    Oxygen index methods are widely used to measure the flammability of polymers and to investigate the effectiveness of fire retardants. Using a dynamical systems model an oxygen index is identified with an extinction limit point. The action of the fire retardant is investigated by unfolding this bifurcation point with a suitable continuation parameter which reflects the mode of action of the additive. The fire retardant mechanisms that we consider are non-competitive char formation and dilution by addition of an inert filler. We investigate which types of material are best retarded by each mechanism.

  7. Unidentified Inert Ingredients in Pesticides: Implications for Human and Environmental Health

    Microsoft Academic Search

    Caroline Cox; Michael Surgan

    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

  8. The performance improvements of train suspension systems with mechanical networks employing inerters

    Microsoft Academic Search

    Fu-Cheng Wang; Min-Kai Liao; Bo-Huai Liao; Wei-Jiun Su; Hsiang-An Chan

    2009-01-01

    This paper investigates the performance benefits of train suspension systems employing a new mechanical network element called an inerter. An inerter is a true mechanical two-terminal element with the applied force proportional to the relative acceleration across the terminals. Until now, ideal inerters have been applied to car and motorcycle suspension systems, for which a significant performance improvement was reported.

  9. 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.

  10. Inert scalars and vacuum metastability around the electroweak scale

    E-print Network

    Swiezewska, Bogumila

    2015-01-01

    We analyze effective potential around the electroweak (EW) scale in the Standard Model (SM) extended with heavy inert scalars. We show that the additional scalars can have a strong impact on the issue of vacuum stability. Although the additional heavy scalars may improve the behavior of running Higgs self-coupling at large field values, we prove that they can destabilize the vacuum due to EW-scale effects. A new EW symmetry conserving minimum of the effective potential can appear rendering the electroweak symmetry breaking (EWSB) minimum meta- or unstable. However, for the case of the inert doublet model (IDM) with a 125 GeV Higgs boson we demonstrate that the parameter space region where the vacuum is meta- or unstable cannot be reconciled with the constraints from perturbative unitarity, electroweak precision tests (EWPT) and dark matter relic abundance measurements.

  11. Significant gamma lines from inert Higgs dark matter.

    PubMed

    Gustafsson, Michael; Lundström, Erik; Bergström, Lars; Edsjö, Joakim

    2007-07-27

    One way to unambiguously confirm the existence of particle dark matter and determine its mass would be to detect its annihilation into monochromatic gamma-rays in upcoming telescopes. One of the most minimal models for dark matter is the inert doublet model, obtained by adding another Higgs doublet with no direct coupling to fermions. For a mass between 40 and 80 GeV, the lightest of the new inert Higgs particles can give the correct cosmic abundance of cold dark matter in agreement with current observations. We show that for this scalar dark matter candidate, the annihilation signal of monochromatic gammagamma and Zgamma final states would be exceptionally strong. The energy range and rates for these gamma-ray line signals make them ideal to search for with the soon upcoming GLAST satellite. PMID:17678348

  12. Significant Gamma Lines from Inert Higgs Dark Matter

    E-print Network

    Michael Gustafsson; Erik Lundstrom; Lars Bergstrom; Joakim Edsjo

    2007-10-05

    One way to unambiguously confirm the existence of particle dark matter and determine its mass would be to detect its annihilation into monochromatic gamma-rays in upcoming telescopes. One of the most minimal models for dark matter is the inert doublet model, obtained by adding another Higgs doublet with no direct coupling to fermions. For a mass between 40 and 80 GeV, the lightest of the new inert Higgs particles can give the correct cosmic abundance of cold dark matter in agreement with current observations. We show that for this scalar dark matter candidate, the annihilation signal of monochromatic \\gamma\\gamma and Z\\gamma final states would be exceptionally strong. The energy range and rates for these gamma-ray line signals make them ideal to search for with the soon upcoming GLAST satellite.

  13. Inert supports for lactic acid fermentation —a technological assessment

    Microsoft Academic Search

    L. M. D. Gonçalves; M. T. O. Barreto; A. M. B. R. Xavier; M. J. T. Carrondo; J. Klein

    1992-01-01

    Production of lactic acid using Lactobacillus delbrueckii NRRL B445 recently renamed L. rhamnosus was studied in continuously recycled packed reactors at pH 6.3 and 42° C. Four inert adsorbent supports were used for immobilization: Raschig rings of sintered glass (Schott, FRG), beads of sintered glass (Schott), beads of porous glass (Poraver; Dennert, FRG) and irregular ceramic particles (Otto Feuerfest, FRG).

  14. 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.

  15. Scalar Dark Matter Candidates in Two Inert Higgs Doublet Model

    E-print Network

    E. C. F. S. Fortes; A. C. B. Machado; J. Montaño; V. Pleitez

    2014-07-17

    We study a two scalar inert doublet model (IDMS$_3$) which is stabilized by a $S_3$ symmetry. We consider two scenarios: i) two of the scalars in each charged sector are mass degenerated due to a residual $Z_2$ symmetry, ii) there is no mass degeneracy because of the introduction of soft terms that break the $Z_2$ symmetry. We show that both scenarios provide good dark matter candidates for some range of parameters.

  16. The inert doublet model of dark matter revisited

    Microsoft Academic Search

    Laura Lopez Honorez; Carlos E. Yaguna

    2010-01-01

    The inert doublet model, a minimal extension of the Standard Model by a second higgs doublet with no direct couplings to quarks or leptons, is one of the simplest scenarios that can explain the dark matter. In this paper, we study in detail the impact of dark matter annihilation into the three-body final state W{W^*}left( { to Wfbar{f}'} right) on

  17. 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.

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

    E-print Network

    Hindmarsh, Mark; No, Jose Miguel; West, Stephen M

    2014-01-01

    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 detectio...

  19. 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.

  20. Application of cryocoolers to a vintage dilution refrigerator

    NASA Astrophysics Data System (ADS)

    Schmitt, Richard L.; Smith, Gary; Ruschman, Mark; Beaty, Jim

    2012-06-01

    A dilution refrigerator is required for 50 mK 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 80 K and at 4 K. 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.

  1. Experimental research of the effect of hydrogen in argon as a shielding gas in arc welding of high-alloy stainless steel

    Microsoft Academic Search

    M. Suban

    2000-01-01

    The paper treats the effect of hydrogen in argon as a shielding gas in arc welding of austenitic stainless steel. The studies were carried out in TIG (Tungsten Inert Gas) welding with a non-consumable electrode and MIG (Metal Inert Gas) welding with a consumable electrode, in both cases with different volume additions of hydrogen to the argon shielding gas, i.e.,

  2. Dilution and the elusive baseline.

    PubMed

    Likens, Gene E; Buso, Donald C

    2012-04-17

    Knowledge of baseline conditions is critical for evaluating quantitatively the effect of human activities on environmental conditions, such as the impact of acid deposition. Efforts to restore ecosystems to prior, "pristine" condition require restoration targets, often based on some presumed or unknown baseline condition. Here, we show that rapid and relentless dilution of surface water chemistry is occurring in the White Mountains of New Hampshire, following decades of acid deposition. Extrapolating measured linear trends using a unique data set of up to 47 years, suggest that both precipitation and streamwater chemistry (r(2) >0.84 since 1985) in the Hubbard Brook Experimental Forest (HBEF) will approximate demineralized water within one to three decades. Because such dilute chemistry is unrealistic for surface waters, theoretical baseline compositions have been calculated for precipitation and streamwater: electrical conductivity of 3 and 5 ?S/cm, base cation concentrations of 7 and 39 ?eq/liter, acid-neutralizing capacity values of <1 and 14 ?eq/liter, respectively; and pH 5.5 for both. Significantly large and rapid dilution of surface waters to values even more dilute than proposed for Pre-Industrial Revolution (PIR) conditions has important ecological, biogeochemical and water resource management implications, such as for the success of early reproductive stages of aquatic organisms. PMID:22455659

  3. 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.

  4. Dry Dilution Refrigerator with He-4 Precool Loop

    E-print Network

    Uhlig, K

    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 that the 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 ...

  5. Buoyant Response of the Tank 241-SY-101 Crust to Transfer and Back-Dilution

    SciTech Connect

    CW Stewart

    1999-11-08

    The mixer pump installed in Hanford Tank 241-SY-101 (SY-101) in July 1993 has prevented the large buoyant displacement gas release events (BD GRE) it has historically exhibited. But the absence of periodic disruption from GREs and the action of mixing have allowed the crust to grow. The accelerated gas retention has resulted in over 30 inches of waste level growth and the flammable gas volume stored in the crust has become a hazard. To remediate gas retention in the crust and the potential for buoyant displacement gas releases from below the crust, SY-101 will be diluted in the fall of 1999 to dissolve a large fraction of the solids in the tank. The plan is to transfer waste out and back-dilute with water in several steps of about 100,000 gallons each. Back-dilution water may be added at the transfer pump inlet, the base of the mixer pump, and on top of the crust. The mixer pump will continue to be required to prevent formation of a deep nonconnective layer and resumption of BD GREs. Therefore, it is vital to ensure that the transfer and back-dilution processes do not significantly degrade the pump's effectiveness. Part of the strategy to avoid mixer pump degradation is to keep the base of the crust layer well above the pump inlet, which is 236 inches above the tank bottom. The maximum transfer for which an equal back-dilution is possible without sinking the crust is 90 kgal if water is injected at the 96-inch transfer pump inlet and 120 kgal for injection at the 9-inch mixer pump burrowing ring. To keep the crust base above the lowest observed elevation of 295 inches, transfer and back-dilution must be limited to 143 kgal and 80 kgal, respectively, for the 96-inch back-dilution and 175 kgal with a 112 kgal back-dilution using the 9-inch back-dilution elevation. These limits can be avoided by adding water to the top of the crust to dissolve the negatively buoyant layers. If 20 kgal of water is placed on top of the crust and the rest of the back-dilution is placed under the crust, back-dilution becomes limited by crust sinking at a 128 kgal transfer using the 96-inch injection point and at 160 kgal at 9 inches. The crust base remains well above the 295-inch minimum, and crust base elevation does not limit transfer volume. This result shows that top dilution is very beneficial in providing operational flexibility to the transfer and back-dilution process.

  6. 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.

  7. 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.

  8. Inert Electrodes Program: Fiscal year 1990 annual report

    SciTech Connect

    Windisch, C.F. Jr; Strachan, D.M.

    1991-08-01

    The Inert Electrodes Program, 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, cathodes, and ancillary equipment. During the FY 1989 and FY 1990, preparations for the pilot cell test continued. Numerous unanticipated problems were encountered that delayed the test schedule. The delays resulted primarily from three factors: (1) modifications for anode design based on the results obtained from the prototype test (documented here); (2) difficulties in procuring a manufacturer for the cermet inert anodes to be used in the pilot cell; and (3) problems in the actual scale-up activities, both in the production of the ferrite powder and in the fabrication of the anodes themselves. Issues related to scaling up the fabrication of the anodes are still being addressed in FY 1991. Important accomplishments in FY 1989 and FY 1990 include the completion of laboratory cell tests in which the effects of current density, pre-corrosion, and silica content on anode performance were confirmed; the performance of tests that resulted in the identification of the reaction layer on cermet anodes; the initiation of electrochemical tests to determine the source of the anode impedance; the completion of studies to identify and summarize optimal fabrication conditions for the cermet inert anodes, including advanced compositions; the testing of anodes with advanced composition; the refinement of the electrical connection for the anode; and modeling the dynamics of the anode array to be used in the pilot cell. 15 refs., 23 figs.

  9. Angiographic Results in Intracranial Aneurysms Treated with Inert Platinum Coils

    PubMed Central

    Vanzin, J.R.; Mounayer, C.; Abud, D.G.; D'agostini Annes, R.; Moret, J.

    2012-01-01

    Summary This study was designed in an attempt to identify the risk factors that could be significantly associated with angiographic recurrences after selective endovascular treatment of aneurysms with inert platinum coils. A retrospective analysis of all patients with selective endovascular coil occlusion of intracranial aneurysms was prospectively collected from 1999 to 2003. There were 455 aneurysms treated with inert platinum coils and followed by digital subtraction angiography. Angiographic results were classified according Roy and Raymond's classification. Recurrences were subjectively divided into minor and major. The most significant predictors for angiographic recurrences were determined by ANOVAs logistic regression, Cochran-Mantel-Haenszel test, Fisher exact probability. Short-term (4.3±1.4 months) follow-up angiograms were available in 377 aneurysms, middle-term (14.1±4.0 months) in 327 and long-term (37.4±11.5 months) in 180. Recurrences were found in 26.8% of treated aneurysms with a mean of 21±15.7 months of follow-up. Major recurrences needing retreatment were present in 8.8% during a mean period follow-up of 17.9±12.29 months after the initial endovascular treatment. One patient (0.2%) experienced a bleed during the follow-up period. Recurrences after endovascular treatment of aneurysms with inert platinum coils are frequent, but hemorrhages are unusual. Single aneurysm, ruptured aneurysm, neck greater than 4 mm and time of follow-up were risk factors for recurrence after endovascular treatment. The retreatment of recurrent aneurysm decreases the risk of major recurrences 9.8 times. Long-term angiogram monitoring is necessary for the population with significant recurrence predictors. PMID:23217634

  10. 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.

  11. 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.

  12. Inert scalar dark matter in an extra dimension inspired model

    NASA Astrophysics Data System (ADS)

    Lineros, R. A.; Pereira dos Santos, F. A.

    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.

  13. Asymptotic analysis of stationary adiabatic premixed flames in porous inert media

    SciTech Connect

    Pereira, Fernando M.; Oliveira, Amir A.M. [Departamento de Engenharia Mecanica, Universidade Federal de Santa Catarina, 88040-900 Florianopolis, SC (Brazil); Fachini, Fernando F. [Instituto Nacional de Pesquisas Espaciais, 12630-000 Cachoeira Paulista, SP (Brazil)

    2009-01-15

    The structure of adiabatic premixed flames within porous inert media is investigated using the asymptotic expansion method. For this, the flame structure is divided into three characteristic length scales. The two innermost length scales, the gas-phase diffusion length scale and the reaction length scale, are the same scales defined in the classical premixed flame structure analysis. The outermost length scale, the solid-phase diffusion length scale, is related to the heat conduction in the porous matrix. The differences among these three characteristic length-scales result in large temperature differences between the phases and justify the application of asymptotic expansions to determine an approximate (analytical) solution. Since the main focus of this work is the examination of the processes in the outer and the first inner regions, the simplest kinetic mechanism of one global step is adopted to represent the fuel and oxygen consumption. Then, the description of the reaction zone is obtained using the large activation energy asymptotic method. The description of the problem of the order of the gas-phase length scale is obtained using the boundary layer expansion. This work evaluates the influence of the equivalence ratio, the ratio of the solid to the gas thermal conductivities, the porosity of the medium and the fuel Lewis number on such flames. A parameter that universalizes the flame properties is then identified and discussed. (author)

  14. Asymptotic analysis of stationary adiabatic premixed flames in porous inert media

    SciTech Connect

    Pereira, Fernando M.; Oliveira, Amir A.M. [Departamento de Engenharia Mecanica, Universidade Federal de Santa Catarina, 88040-900 Florianopolis, SC (Brazil); Fachini, Fernando F. [Instituto Nacional de Pesquisas Espaciais, 12630-000 Cachoeira Paulista, SP (Brazil)

    2008-11-15

    The structure of adiabatic premixed flames within porous inert media is investigated using the asymptotic expansion method. For this, the flame structure is divided into three characteristic length scales. The two innermost length scales, the gas-phase diffusion length scale and the reaction length scale, are the same scales defined in the classical premixed flame structure analysis. The outermost length scale, the solid-phase diffusion length scale, is related to the heat conduction in the porous matrix. The differences among these three characteristic length-scales result in large temperature differences between the phases and justify the application of asymptotic expansions to determine an approximate (analytical) solution. Since the main focus of this work is the examination of the processes in the outer and the first inner regions, the simplest kinetic mechanism of one global step is adopted to represent the fuel and oxygen consumption. Then, the description of the reaction zone is obtained using the large activation energy asymptotic method. The description of the problem of the order of the gas-phase length scale is obtained using the boundary layer expansion. This work evaluates the influence of the equivalence ratio, the ratio of the solid to the gas thermal conductivities, the porosity of the medium and the fuel Lewis number on such flames. A parameter that universalizes the flame properties is then identified and discussed. (author)

  15. Tracer-dilution method indicates flowrate through compressor

    SciTech Connect

    Lagus, P.L.; Flanagan, B.S. (Lagus Applied Technology Inc., San Diego, CA (US)); Peterson, M.E. (Tennessee Gas Pipeline Co., Middleton, TN (US)); Clowney, S.L. (Tenneco Gas, Houston, TX (US))

    1991-02-25

    A technique for measuring compressor flowrate through an operating natural-gas centrifugal compressor has been tested and found to have a precisions approaching {plus minus}1.5%. The technique employs constant-flow tracer dilution. Testing demonstrated that use of a critical-flow nozzle to inject a constant, known flow of tracer into a flowing natural-gas stream is feasible. Effects of potential pulsation on a tracer flow measurement appear to be eliminated by this technique. With experimental and operational streamlining, the constant-flow tracer dilution technique is capable of being used to measure the flowrate through operating centrifugal compressors with sufficient precisions and accuracy to allow compressor operating characteristics to be determined. This technique is especially useful in situations in which an orifice-flow measurement cannot be performed because of physical space limits or economic considerations.

  16. Sea Urchin Embryology: Simple Dilutions 2

    NSDL National Science Digital Library

    PhD David Epel (Stanford U. Hopkins Marine Station)

    2006-12-20

    SUMMARY: Building on what was learned in SIMPLE DILUTION, students will determine the best dilution strategy to solve a dilution problem. 1. Students are given an unknown dye solution and asked to determine its concentration by comparing it with standards they create. 2. Repeated "serial" dilutions will be necessary to determine accurate concentration readings. 3. Varying the color of the filters and the path length will aid in seeing lower concentrations.

  17. Botulinum toxin: dosing and dilution.

    PubMed

    Francisco, Gerard E

    2004-10-01

    In the United States, the popularity of botulinum toxins as agents to treat muscle hypertonia has grown significantly over the last decade, despite lack of approval from the Food and Drug Administration for the indication of spasticity. Botox (botulinum toxin type A) and Myobloc (botulinum toxin type B) are Food and Drug Administration-approved for other indications, such as cervical dystonia. Another commercial preparation of type A, Dysport, has yet to reach the United States market as of this writing. Although botulinum toxin's efficacy in influencing spastic hypertonia is well accepted, the impact of certain clinical issues, such as dosing and dilution, on treatment outcome is not well established by published studies. This article will review important articles and selected abstracts on the use of botulinum toxin, specifically for spastic hypertonia in adults, with emphasis on current clinical practices as they relate to dosing and dilution. PMID:15448575

  18. BASIC RESEARCH ON HIGH DILUTION EFFECTS

    Microsoft Academic Search

    MADELEINE BASTIDE

    Basic research on high dilution effects started with homeopathic therapy. So many models have been tested that we have tried to classify them according to the general concept of regulation. Firstly, succussed dilutions must be separated from unsuccussed very low doses from a physical point of view. This leads us to discuss the validity of the controls in high dilution

  19. 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…

  20. Cryogen-free dilution refrigerators

    NASA Astrophysics Data System (ADS)

    Uhlig, K.

    2012-12-01

    We review briefly our first cryogen-free dilution refrigerator (CF-DR) which was precooled by a GM cryocooler. We then show how today's dry DRs with pulse tube precooling have developed. A few examples of commercial DRs are explained and noteworthy features pointed out. Thereby we describe the general advantages of cryogen-free DRs, but also show where improvements are still desirable. At present, our dry DR has a base temperature of 10 mK and a cooling capacity of 700 ?W at a mixing chamber temperature of 100 mK. In our cryostat, in most recent work, an additional refrigeration loop was added to the dilution circuit. This 4He circuit has a lowest temperature of about 1 K and a refrigeration capacity of up to 100 mW at temperatures slightly above 1 K; the dilution circuit and the 4He circuit can be run separately or together. The purpose of this additional loop is to increase the cooling capacity for experiments where the cooling power of the still of the DR is not sufficient to cool cold amplifiers and cables, e.g. in studies on superconducting quantum circuits or astrophysical applications.

  1. 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.

  2. IDMS: Inert Dark Matter Model with a complex singlet

    E-print Network

    Cesar Bonilla; Dorota Sokolowska; Neda Darvishi; J. Lorenzo Diaz-Cruz; Maria Krawczyk

    2015-04-13

    Within the Inert Doublet Model (IDM) there is a viable dark matter candidate. This simple model can provide a strong enough first order phase transition, which is required in order to account for the matter-antimatter asymmetry in the Universe (BAU). However, another necessary ingredient is missing, as there is no additional source of CP violation in the IDM, besides the standard CKM phase from the Standard Model. Additional CP violating phase can appear if a complex singlet of $SU(3)_C \\times SU(2)_W \\times U(1)_Y$ with a non-zero vacuum expectation value is added to the scalar sector of the IDM. We construct the scalar potential of the inert doublet plus singlet model (IDMS), assuming an exact $Z_2$ symmetry, with singlet being $Z_2$-even. To simplify the model we use a softly broken $U(1)$ symmetry, which allows a reduction of the number of free parameters in the potential. We study the masses and interactions of scalar particles for a few benchmark scenarios. Constraints from collider physics, in particular from the Higgs signal observed at LHC with $M_h\\approx 125$ GeV are discussed, as well as constraints from the dark matter experiments.

  3. Teflon films for chemically-inert microfluidic valves and pumps.

    PubMed

    Grover, William H; von Muhlen, Marcio G; Manalis, Scott R

    2008-06-01

    We present a simple method for fabricating chemically-inert Teflon microfluidic valves and pumps in glass microfluidic devices. These structures are modeled after monolithic membrane valves and pumps that utilize a featureless polydimethylsiloxane (PDMS) membrane bonded between two etched glass wafers. The limited chemical compatibility of PDMS has necessitated research into alternative materials for microfluidic devices. Previous work has shown that spin-coated amorphous fluoropolymers and Teflon-fluoropolymer laminates can be fabricated and substituted for PDMS in monolithic membrane valves and pumps for space flight applications. However, the complex process for fabricating these spin-coated Teflon films and laminates may preclude their use in many research and manufacturing contexts. As an alternative, we show that commercially-available fluorinated ethylene-propylene (FEP) Teflon films can be used to fabricate chemically-inert monolithic membrane valves and pumps in glass microfluidic devices. The FEP Teflon valves and pumps presented here are simple to fabricate, function similarly to their PDMS counterparts, maintain their performance over extended use, and are resistant to virtually all chemicals. These structures should facilitate lab-on-a-chip research involving a vast array of chemistries that are incompatible with native PDMS microfluidic devices. PMID:18497911

  4. IDMS: Inert Dark Matter Model with a complex singlet

    E-print Network

    Cesar Bonilla; Dorota Sokolowska; J. Lorenzo Diaz-Cruz; Maria Krawczyk; Neda Darvishi

    2014-12-30

    Within the Inert Doublet Model (IDM) there is a viable dark matter candidate. This simple model can provide a strong enough first order phase transition, which is required in order to account for the matter-antimatter asymmetry in the Universe (BAU). However, another necessary ingredient is missing, as there is no additional source of CP violation in the IDM, besides the standard CKM phase from the Standard Model. Additional CP violating phase can appear if a complex singlet of $SU(3)_C \\times SU(2)_W \\times U(1)_Y$ with a non-zero vacuum expectation value is added to the scalar sector of the IDM. We construct the scalar potential of the inert doublet plus singlet model (IDMS), assuming an exact $Z_2$ symmetry, with singlet being $Z_2$-even. To simplify the model we use a softly broken $U(1)$ symmetry, which allows a reduction of the number of free parameters in the potential. We study the masses and interactions of scalar particles for a few benchmark scenarios. Constraints from collider physics, in particular from the Higgs signal observed at LHC with $M_h\\approx 125$ GeV are discussed, as well as constraints from the dark matter experiments.

  5. 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.

  6. Fabrication and characterization of inert-substrate-supported tubular single cells by dip-coating process

    NASA Astrophysics Data System (ADS)

    Zhao, Kai; Kim, Bok-Hee; Xu, Qing; Ahn, Byung-Guk

    2014-01-01

    A tubular single cell supported by an inert substrate with a configuration of porous yttria-stabilized zirconia (YSZ) supporter/Ni anode current collector/Ni-Ce0.8Sm0.2O1.9 anode/YSZ/Ce0.8Sm0.2O1.9 bi-layer electrolyte/La0.6Sr0.4Co0.2Fe0.8O3-? cathode has been fabricated by a cold isostatic pressing and dip-coating process. The effects of pore morphology and porosity of the YSZ supporter on the mechanical strength and electrochemical performance of the single cell have been investigated with respect to the content of poly (methyl methacrylate) (PMMA) pore former. The average pore size and porosity of the YSZ supporter increase with the amount of pore former used, facilitating the gas diffusion process at the anode and reducing the polarization resistance of the single cell whereas leading to a decline of the mechanical strength. A preferred pore former content is determined to be 25 wt.% based on a trade-off of the mechanical strength and electrochemical performance. The single cell with 25 wt.% PMMA in YSZ supporter shows a bending strength of 21 ± 1 MPa and a maximum power density of 337 mW cm-2 at 800 °C in hydrogen. Moreover, the inert-substrate-supported tubular single cell displays a satisfactory redox cycling stability, maintaining 95% of its initial performance within seven redox cycles.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. Dilute oxygen combustion. Phase I report

    SciTech Connect

    NONE

    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.

  13. Characteristics of Discharge in a DC Corona Reactor for Removing Dilute SF6

    NASA Astrophysics Data System (ADS)

    Minamitani, Yasushi; Sugimoto, Toshiyuki; Higashiyama, Yoshio

    A DC corona reactor using electron attachment is utilized to remove dilute fluorocarbon in an air-conditioning unit or SF6 in a gas circuit breaker. By employing helium gas to purge the low concentrated gas in the unit, corona onset voltage in the corona reactor decreases. We observed the characteristics of corona discharge for the pure helium gas with flow and for the helium gas contained dilute SF6 gas at atmospheric pressure. In pure helium gas, luminous spots appeared along the discharging wire. The number of luminous spots without gas flow increased stepwise with the discharging current. In contrast, the luminous spots decreased as the gas flow rate increased. In the helium gas containing dilute SF6, corona discharge occurred uniformly along the discharging wire initially. As the time elapsed, the discharge aspects drastically changed: The discharge voltage gradually decreased to that in the pure helium gas and the uniform corona discharge along the discharging wire changed to a single spot.

  14. Can low-temperature thermoluminescence cast light on the nature of ultra-high dilutions?

    PubMed

    Rey, Louis

    2007-07-01

    Low-temperature thermoluminescence has been used in attempt to understand the particular structure of ultra high dilutions. Samples are activated by irradiation after freezing at the temperature of liquid nitrogen (77 degrees K). Experimental results show that, in the course of rewarming, the thermoluminescent glow is susbtantially different between dilutions of different substances. It is suggested that the dispersed gas phase might play a role in this process. PMID:17678813

  15. 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.

  16. Dilute Acid and Autohydrolysis Pretreatment

    NASA Astrophysics Data System (ADS)

    Yang, Bin; Wyman, Charles E.

    Exposure of cellulosic biomass to temperatures of about 120-210°C can remove most of the hemicellulose and produce cellulose-rich solids from which high glucose yields are possible with cellulase enzymes. Furthermore, the use of dilute sulfuric acid in this pretreatment operation can increase recovery of hemicellulose sugars substantially to about 85-95% of the maximum possible versus only about 65% if no acid is employed. The use of small-diameter tubes makes it possible to employ high solids concentrations similar to those preferred for commercial operations, with rapid heat-up, good temperature control, and accurate closure of material balances. Mixed reactors can be employed to pretreat larger amounts of biomass than possible in such small-diameter tubes, but solids concentrations are limited to about 15% or less to provide uniform temperatures. Pretreatment of large amounts of biomass at high solids concentrations is best carried out using direct steam injection and rapid pressure release, but closure of material balances in such “steam gun” devices is more difficult. Although flow of water alone or containing dilute acid is not practical commercially, such flow-through configurations provide valuable insight into biomass deconstruction kinetics not possible in the batch tubes, mixed reactors, or steam gun systems.

  17. 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.

  18. Numerical Simulation of Dispersal of Inert Seeding Material in Israel Using a Three-Dimensional Mesoscale Model.

    NASA Astrophysics Data System (ADS)

    Levin, Zev; Krichak, Shimon O.; Reisin, Tamir

    1997-05-01

    A mesoscale model RAMS (the Regional Atmospheric Modeling System) was used to investigate the effectiveness of the broadcast static seeding method for dispersing particles into clouds, as it is used in Israel. The model was run using three nested grids, with 500 m × 500 m horizontal resolution in the finest grid. In this paper, the particles were assumed to be inert; namely, only the wind field controlled the dispersal of the tracer particles, and no interaction with cloud or precipitation particles was considered. Although the resolution of the model is good for mesoscale studies, it could not resolve individual plumes. The results, therefore, present average values of the concentrations at each level. The simulations showed that seeding particles reach altitudes at which they could become effective as ice nuclei. These cases were primarily the ones in which the updrafts developed over the seeding lines when the seeding plane was just passing underneath. In these cases only, seeding at about 1-km level (4°C) with 500 g h1 of inert material (simulating AgI particles) resulted in about 1 × 103-2 × 103 L1 being lifted to the 10°C level. Based on previous laboratory studies of the seeding agent used in Israel, out of these total concentrations, only 1-2 L1 could form ice at 10°C. The simulations also suggest that in most other cases the horizontal advection diluted the particles in the air and only very low concentrations (<103 L1, active at 10°C) reached the 10°C level. Most other released particles were transported horizontally with the winds and were later on forced down by downdrafts. Although these simulations await some experimental verification, they suggest that the broadcast seeding method used in Israel is not so effective for widespread rain enhancement operations.

  19. 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.

  20. 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

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. Young Infants' Reasoning about Physical Events Involving Inert and Self-Propelled Objects

    ERIC Educational Resources Information Center

    Luo, Yuyan; Kaufman, Lisa; Baillargeon, Renee

    2009-01-01

    The present research examined whether 5- to 6.5-month-old infants would hold different expectations about various physical events involving a box after receiving evidence that it was either inert or self-propelled. Infants were surprised if the inert but not the self-propelled box: reversed direction spontaneously (Experiment 1); remained…

  6. Inert doublet dark matter and mirror\\/extra families after Xenon100

    Microsoft Academic Search

    Alejandra Melfo; Miha Nemevsek; Fabrizio Nesti; Goran Senjanovic; Yue Zhang

    2011-01-01

    It was shown recently that mirror fermions, naturally present in a number of directions for new physics, seem to require an inert scalar doublet in order to pass the electroweak precision tests. This provides a further motivation for considering the inert doublet as a dark matter candidate. Moreover, the presence of extra families enhances the standard model Higgs-nucleon coupling, which

  7. 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.

  8. 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.

  9. Desynchronization in diluted neural networks

    SciTech Connect

    Zillmer, Ruediger [INFN Sezione Firenze, via Sansone 1, I-50019 Sesto Fiorentino (Italy); Livi, Roberto [Dipartimento di Fisica, Universita di Firenze, via Sansone 1, I-50019 Sesto Fiorentino (Italy); Sezione INFN, Unita' INFM e Centro Interdipartimentale per lo Studio delle Dinamiche Complesse, via Sansone 1, I-50019 Sesto Fiorentino (Italy); Politi, Antonio; Torcini, Alessandro [Istituto dei Sistemi Complessi, CNR, CNR, via Madonna del Piano 10, I-50019 Sesto Fiorentino (Italy); Centro Interdipartimentale per lo Studio delle Dinamiche Complesse, via Sansone 1, I-50019 Sesto Fiorentino (Italy)

    2006-09-15

    The dynamical behavior of a weakly diluted fully inhibitory network of pulse-coupled spiking neurons is investigated. Upon increasing the coupling strength, a transition from regular to stochasticlike regime is observed. In the weak-coupling phase, a periodic dynamics is rapidly approached, with all neurons firing with the same rate and mutually phase locked. The strong-coupling phase is characterized by an irregular pattern, even though the maximum Lyapunov exponent is negative. The paradox is solved by drawing an analogy with the phenomenon of 'stable chaos', i.e., by observing that the stochasticlike behavior is 'limited' to an exponentially long (with the system size) transient. Remarkably, the transient dynamics turns out to be stationary.

  10. Fiscal year 1989 annual report for the Sensors Development Program: Inert Electrodes Program

    SciTech Connect

    Windisch, C.F. Jr.; Koski, O.H.; Stice, N.D.; Morgan, L.G. (Pacific Northwest Lab., Richland, WA (USA)); Nikias, C.L. (Northeastern Univ., Boston, MA (USA))

    1990-04-01

    The Sensors Development Program is conducted at the Pacific Northwest Laboratory (PNL) for the US Department of Energy (DOE), Office of Industrial Programs (OIP). The work is being performed in conjunction with the Inert Electrodes Program at PNL. The objectives of the Sensors Development Program are to (1) investigate and develop methods of process monitoring/control for operating electrolytic cells and (2) determine safe operating conditions for the inert anodes. The majority of work in FY 1989 involved (1) evaluating Digital Signal Analysis (DSA) methods to monitor inert anode operation and to determine alumina concentration in both PNL bench-scale laboratory cells and the Prototype Inert Anode Test and (2) developing the reference anode against which inert anode voltage signals could be measured by the DSA-based or other methods. 3 refs., 14 figs., 2 tabs.

  11. 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.

  12. Sunlight photochemistry of retort-water organonitrogen compounds in an inert atmosphere

    SciTech Connect

    Blatchley, E.R. III; Daughton, C.G.; Thomas, J.F.

    1986-04-01

    The elevated temperature of an oil-shale codisposal process will enhance the atmospheric emission of volatile components. Important among the organic compounds are the nitrogen heterocycles and aromatic primary amines, which are chacterized by malodor and low order thresholds and by resistance to biotreatment. Atmospheric lifetimes are determined by various transport (e.g., dispersion, washout) and transformation phenomena. Photochemical alteration will be the major transformation process. Those compounds that degrade quickly may increase the atmospheric NO/sub x/ concentration, giving the potential for photochemical smog formation. Those with longer lifetimes may present health and aesthetic problems. The broad spectrum of compound types and isomers present in process-water headspace samples may result in a range of atmospheric lifetimes. The work reported here is the first investigation of vapor-phase atmospheric photoreactions leading to degradation of organonitrogen compounds emitted from process waters. Only direct photochemical reactions were studied. Headspace samples (65/sup 0/C) were generated in an inert atmosphere (N/sub 2/ gas) and exposed to atmospheric radiation in Tedlar gas-sampling bags. Headspace composition was monitored by capillary gas chromatography with flame thermionic or flame ionization detection. Time-course headspace analyses compared exposed and unexposed samples, and individual compounds were monitored to determine the degree of individual photochemical losses. Under these conditions, the alkylpyridines did not photodegrade, in contrast to other nitrogen heterocycles (e.g., pyrrole) and aromatic primary amines. This is significant because alkylpyridines comprise the largest portion of organonitrogen compounds emitted from process waters. It is anticipated that indirect photoreactions (e.g., radical-mediated) will be more extensive and important. 35 refs., 6 figs., 1 tab.

  13. 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.

  14. Dry dilution refrigerator with He-4 precool loop

    SciTech Connect

    Uhlig, Kurt [Walther-Meissner-Institute, 85748 Garching (Germany)

    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.

  15. 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.

  16. All optical O2 sensors using innovative phase fluorimetry for monitoring of headspace in ullage for FAA mandated inerting fuel tanks of commercial airlines

    NASA Astrophysics Data System (ADS)

    Panahi, Allen

    2011-06-01

    This paper explores the design and development of an all optical O2 sensor system that can be used for monitoring of headspace gases in the ullage of inerting fuel tanks of commercial airplanes. Also included is detailed discussion of 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.

  17. À propos des dilutions homéopathiques des vaccins

    Microsoft Academic Search

    Marie-Noëlle Domalain; Florence Peyrefitte; Bernard Poitevin

    2010-01-01

    Vaccine dilutions are used in homeopathy for different purposes, for example to limit the side effects of vaccines or to prevent diseases in certain cases. However, in the absence of any scientific information on how they work, vaccine dilutions prepared using homeopathic methods can in no circumstances be used in place of legal vaccination.

  18. Inert dark matter in type-II seesaw

    NASA Astrophysics Data System (ADS)

    Chen, Chuan-Hung; Nomura, Takaaki

    2014-09-01

    Weakly interacting massive particle (WIMP) as a dark matter (DM) candidate is further inspired by recent AMS-02 data, which confirm the excess of positron fraction observed earlier by PAMELA and Fermi-LAT experiments. Additionally, the excess of positron+electron flux is still significant in the measurement of Fermi-LAT. For solving the problems of massive neutrinos and observed excess of cosmic-ray, we study the model with an inert Higgs doublet (IHD) in the framework of type-II seesaw model by imposing a Z 2 symmetry on the IHD, where the lightest particle of IHD is the DM candidate and the neutrino masses originate from the Yukawa couplings of Higgs triplet and leptons. We calculate the cosmic-ray production in our model by using three kinds of neutrino mass spectra, which are classified by normal ordering, inverted ordering and quasi-degeneracy. We find that when the constraints of DM relic density and comic-ray antiproton spectrum are taken into account, the observed excess of positron/electron flux could be explained well in normal ordered neutrino mass spectrum. Moreover, excess of comic-ray neutrinos is implied in our model. We find that our results on < ?v> are satisfied with and close to the upper limit of IceCube analysis. More data from comic-ray neutrinos could test our model.

  19. 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.

  20. 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.

  1. 40 CFR 174.533 - Glycine max Herbicide-Resistant Acetolactate Synthase (GM-HRA) inert ingredient; exemption from...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Herbicide-Resistant Acetolactate Synthase (GM-HRA) inert ingredient; exemption...Herbicide-Resistant Acetolactate Synthase (GM-HRA) inert ingredient; exemption...herbicide-resistant acetolactate synthase (GM-HRA) enzyme in or on the food and feed commodities of...

  2. 40 CFR 174.533 - Glycine max Herbicide-Resistant Acetolactate Synthase (GM-HRA) inert ingredient; exemption from...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Herbicide-Resistant Acetolactate Synthase (GM-HRA) inert ingredient; exemption...Herbicide-Resistant Acetolactate Synthase (GM-HRA) inert ingredient; exemption...herbicide-resistant acetolactate synthase (GM-HRA) enzyme in or on the food and feed commodities of...

  3. Laboratory production of zirconium carbide compacts for use in inert matrix fuels

    NASA Astrophysics Data System (ADS)

    Vasudevamurthy, Gokul; Knight, Travis W.; Roberts, Elwyn; Adams, Thad M.

    2008-02-01

    Zirconium carbide is being actively considered for use as an inert matrix material in composite nuclear fuel for gas-cooled fast reactors. ZrC can be produced either by the endothermic carbothermal reduction of zirconium dioxide or by the direct exothermic reaction of pure zirconium and graphite powder mixtures. The exothermic reaction is classified as combustion synthesis or self heating synthesis. Experiments were conducted to demonstrate the combustion synthesis reaction of zirconium and graphite powders and measure the ignition and adiabatic temperatures. The heat released during this short reaction time was sufficient only to partially sinter the compacts to less than 40% theoretical density. Subsequently, compacts of ZrC were similarly produced by combustion synthesis followed by a short, high temperature hold at 2440 °C to relieve residual stresses in the compacts following the rapid reaction sintering. External pressures of up to 5.2 MPa were used as an additional driving force for sintering. The effects of reactant particle size and degree of uniaxial pressing on the product density and porosity were also studied. Higher densities in the fabricated compacts were noted for higher uniaxial pressures irrespective of powder size. Also, smaller powder sizes produced compacts up to 92% TD, while larger particle sizes produced compacts up to 84% TD for the same pressure. The compacts were characterized based on composition, microstructure, and density/porosity. Results of the different experiments are presented.

  4. Response to dietary dilution in an omnivorous freshwater turtle: implications for ontogenetic dietary shifts.

    PubMed

    McCauley, S J; Bjorndal, K A

    1999-01-01

    Several species of freshwater turtles in the family Emydidae undergo an ontogenetic dietary shift; as juvenile turtles mature, they change from a primarily carnivorous to a primarily herbivorous diet. It has been hypothesized that this shift results from an unfavorable ratio of gut capacity to metabolic rate that prevents small reptiles from processing adequate volumes of plant material to meet their energetic demands. Effects of dietary dilution on intake were evaluated in two size classes of red-eared sliders (Trachemys scripta elegans) to test whether small reptiles have a lower capacity to compensate for low-quality diets through increased intake than do larger conspecifics. Artificial diets with an inert diluent were offered to two size classes of turtles, and mass-specific intakes of dry matter, energy, and nitrogen were calculated. Both small (28.7+/-4.9 g body mass, mean mass+/-SD) and large (1,230+/-94 g body mass) turtles compensated for dietary dilution and maintained constant energy and nitrogen intakes on diets with lower energy content than common aquatic plants. Thus, body size did not affect the ability to respond to nutritional dilution, which suggests that processing limitations imposed by small body size do not constrain juveniles from adopting an herbivorous diet. PMID:9882608

  5. 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.

  6. 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.

  7. Phenomenology of the inert (2+1) and (4+2) Higgs doublet models

    NASA Astrophysics Data System (ADS)

    Keus, Venus; King, Stephen F.; Moretti, Stefano

    2014-10-01

    We make a phenomenological study of a model with two inert doublets plus one Higgs doublet [I(2+1)HDM] which is symmetric under a Z2 group, preserved after electroweak symmetry breaking by the vacuum alignment (0,0,v). This model may be regarded as an extension to the model with one inert doublet plus one Higgs doublet [I(1+1)HDM], by the addition of an extra inert scalar doublet. The neutral fields from the two inert doublets provide a viable dark matter (DM) candidate which is stabilized by the conserved Z2 symmetry. We study the new Higgs decay channels offered by the scalar fields from the extra doublets and their effect on the standard model Higgs couplings, including a new decay channel into (off-shell) photon(s) plus missing energy, which distinguishes the I(2+1)HDM from the I(1+1)HDM. Motivated by supersymmetry, which requires an even number of doublets, we then extend this model into a model with four inert doublets plus two Higgs doublets [I(4+2)HDM] and study the phenomenology of the model with the vacuum alignment (0,0,0,0,v ,v). This scenario offers a wealth of Higgs signals, the most distinctive ones being cascade decays of heavy Higgs states into inert ones. Finally, we also remark that the smoking-gun signature of all the considered models is represented by invisible Higgs decays into the lightest inert Higgs bosons responsible for DM.

  8. Silicon nitride etching performance of CH2F2 plasma diluted with argon or krypton

    NASA Astrophysics Data System (ADS)

    Kondo, Yusuke; Ishikawa, Kenji; Hayashi, Toshio; Miyawaki, Yudai; Takeda, Keigo; Kondo, Hiroki; Sekine, Makoto; Hori, Masaru

    2015-04-01

    Etching rates of silicon nitrides (SiN), SiO2, and poly-Si films for CH2F2 plasmas diluted with rare gases are presented by comparing the effects of flow rates of CH2F2 and dilution gases (Ar and Kr). The SiO2 etching rate was considered to be controlled by ion fluxes of the incident CHF2+ and CH2F+ under the conditions for the selective etching of SiO2 and SiN over poly-Si. Interestingly, the SiN etching rate was considerably affected by the dilution gas used. The SiN surface reaction was promoted by F-rich chemistry in the Ar-diluted CH2F2 plasma with a relatively high density of F atoms.

  9. 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.

  10. 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.

  11. Diffusion of Ge in Si1-xGex Si single quantum wells in inert and oxidizing ambients

    E-print Network

    Florida, University of

    Diffusion of Ge in Si1-xGex ÕSi single quantum wells in inert and oxidizing ambients Michelle single quantum well SQW structures subjected to inert- and oxidizing-ambient annealing was investigated in inert and oxidizing ambients were similar, which indicates a vacancy-dominated mechanism. Activation

  12. Knabner, P.; de Neef, M.J.; Summ, G. Transient Numerical Simulation of Combustion in Inert Porous Media

    E-print Network

    Gugat, Martin

    Knabner, P.; de Neef, M.J.; Summ, G. Transient Numerical Simulation of Combustion in Inert Porous governing com­ bustion in inert porous media. The spatial discretization is based on a mixed finite element on the localization of the combustion zone. 1. Introduction Combustion in inert porous media is gaining increasing

  13. Terahertz Radiation from Magnetic Excitations in Diluted Magnetic Semiconductors

    NASA Astrophysics Data System (ADS)

    Rungsawang, R.; Perez, F.; Oustinov, D.; Gómez, J.; Kolkovsky, V.; Karczewski, G.; Wojtowicz, T.; Madéo, J.; Jukam, N.; Dhillon, S.; Tignon, J.

    2013-04-01

    We probed, in the time domain, the THz electromagnetic radiation originating from spins in CdMnTe diluted magnetic semiconductor quantum wells containing high-mobility electron gas. Taking advantage of the efficient Raman generation process, the spin precession was induced by low power near-infrared pulses. We provide a full theoretical first-principles description of spin-wave generation, spin precession, and of emission of THz radiation. Our results open new perspectives for improved control of the direct coupling between spin and an electromagnetic field, e.g., by using semiconductor technology to insert the THz sources in cavities or pillars.

  14. Terahertz radiation from magnetic excitations in diluted magnetic semiconductors.

    PubMed

    Rungsawang, R; Perez, F; Oustinov, D; Gómez, J; Kolkovsky, V; Karczewski, G; Wojtowicz, T; Madéo, J; Jukam, N; Dhillon, S; Tignon, J

    2013-04-26

    We probed, in the time domain, the THz electromagnetic radiation originating from spins in CdMnTe diluted magnetic semiconductor quantum wells containing high-mobility electron gas. Taking advantage of the efficient Raman generation process, the spin precession was induced by low power near-infrared pulses. We provide a full theoretical first-principles description of spin-wave generation, spin precession, and of emission of THz radiation. Our results open new perspectives for improved control of the direct coupling between spin and an electromagnetic field, e.g., by using semiconductor technology to insert the THz sources in cavities or pillars. PMID:23679765

  15. 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.

  16. 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.

  17. Dilepton constraints in the Inert Doublet Model from Run 1 of the LHC

    E-print Network

    Belanger, G; Goudelis, A; Herrmann, B; Kraml, S; Sengupta, D

    2015-01-01

    Searches in final states with two leptons plus missing transverse energy, targeting supersymmetric particles or invisible decays of the Higgs boson, were performed during Run 1 of the LHC. Recasting the results of these analyses in the context of the Inert Doublet Model (IDM) using MadAnalysis 5, we show that they provide constraints on inert scalars that significantly extend previous limits from LEP. Moreover, these LHC constraints allow to test the IDM in the limit of very small Higgs-inert scalar coupling, where the constraints from direct detection of dark matter and the invisible Higgs width vanish.

  18. 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.

  19. Sample Diluter for Detecting Hypergolic Propellants and Other Toxic or Hazardous Gases

    NASA Technical Reports Server (NTRS)

    Barile, R. G.; Hodge, T. R.; Meneghelli, B. J.; Gursky, R.; Lueck, D. E.

    1997-01-01

    Hardware was developed to dilute vapor samples of purged hypergolic propellants (with air) into the range of existing instruments for detection of such toxic vapors. Since these detectors are normally used to monitor at the threshold limit value (TLV), most do not have quantitative capability at percent levels which relate to lower explosion limit (LEL) and fire hazards. For example, the upper limits of Energetic Sciences (ESI) 6000 series detectors used at KSC are 200 parts per million (ppm) for monomethyl hydrazine (MMH) and 500 ppm for nitrogen dioxide (NO2) arising from decomposition of nitrogen tetroxide (N2O4). Orbiter Processing Facility (OPF) personnel servicing Shuttle thrusters need to measure up to 250 ppm MMH and 7500 ppm NO2 with portable, intrinsically safe instruments. Our objective was to quickly fabricate a sample diluter out of existing materials as a temporary measure while other parallel efforts were conducted to provide a commercial or in-house-developed instrument to detect high propellant levels. A 3 to 1 diluter would bring 500 ppm MMH into the range of the existing fuel ESI, and a 30 to 1 diluter would do the same for NO2. In this way, familiar equipment already available would be used, resulting in minimal paperwork, safety, and training impacts and low cost. An MMH vapor sample-diluter was constructed from a 1/4-inch Kynar tee, along with specially designed lengths of sample and dilution tubing. The sample line was 3 feet of Bev-A-Line 4, 1/4 inch tube leading to the straight run of the tee. The side run of the tee had a 17-inch length of Bev-A-Line 4, 1/4-inch tube, for nominal 3 to 1 dilution. A gas sample bag was prepared and assayed at 113 ppm MMH, and diluted vapor sarnples were assayed at 39.5 ppm, or a measured dilution of 2.9 to 1. For NO2, a 316 stainless steel (SS) 1/8-inch tee with 49.5 inches of coiled, 1/8-inch outside diameter (OD) 316 SS tubing was used as the sarnpling end of the dilution system. The side run of the tee was open. The measured dilution ratio, based on the input value of 6,480 ppm NO2 and the average output value of 233 ppm, was 28 to 1. Thus, sample-diluters were successful in diluting concentrated hypergolic propellant vapors, both MMH and N2O4, into the ranges of existing TLV detectors.

  20. Sample Diluter for Detecting Hypergolic Propellants and other Toxic or Hazardous Gases

    NASA Technical Reports Server (NTRS)

    Barile, R. G.; Hodge, T. R.; Meneghelli, B. J.; Gursky, R.; Lueck, D. E.

    1997-01-01

    Hardware was developed to dilute vapor samples of purged hypergolic propellants (with air) into the range of existing instruments for detection of such toxic vapors. Since these detectors are normally used to monitor at the threshold limit value (TLV), most do not have quantitative capability at percent levels which relate to lower explosion limit (LEL) and fire hazards. For example, the upper limits of Energetic Sciences (ESI) 6000 series detectors used at KSC are 200 parts per million (ppm) for monomethyl hydrazine (MMH) and 500 ppm for nitrogen dioxide (NO2) arising from decomposition of nitrogen tetroxide (N2O4). Orbiter Processing Facility (OPF) personnel servicing Shuttle thrusters need to measure up to 250 ppm MMH and 7,500 ppm NO2 with portable, intrinsically safe instruments. Our objective was to quickly fabricate a sample diluter out of existing materials as a temporary measure while other parallel efforts were conducted to provide a commercial or in-house-developed instrument to detect high propellant levels. A 3 to 1 diluter would bring 500 ppm MMH into the range of the existing fuel ESI, and a 30 to 1 diluter would do the same for NO2. In this way, familiar equipment already available would be used, resulting in minimal paperwork, safety, and training impacts and low cost. An MMH vapor sample-diluter was constructed from a 1/4-inch Kynar tee, along with specially designed lengths of sample and dilution tubing. The sample line was 3 feet of Bev-A-Line 4, 1/4-inch tube leading to the straight run of the tee. The side run of the tee had a 17-inch length of Bev-A-Line 4, 1/4-inch tube, for nominal 3 to 1 dilution. A gas sample bag was prepared and assayed at 113 ppm ppm MMH, and diluted vapor samples were assayed at 39.5 ppm, or a measured dilution of 2.9 to 1. For NO2, a 316 stainless steel (SS) 1/8-inch tee with 49.5 inches of coiled, 1/8-inch outside diameter (OD) 316 SS tubing was used as the sampling end of the dilution system. The side run of the tee was open. The measured dilution ratio, based on the input value of 6,480 ppm NO2, and the average output value of 233 ppm, was 28 to 1. Thus, sample-diluters were successful in diluting concentrated hypergolic propellant vapors, both MMH and N2O4 into the ranges of existing TLV detectors.

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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; Neto, Antonio H Castro; 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

  7. Analyses of turbulent flow fields and aerosol dynamics of diesel engine exhaust inside two dilution sampling tunnels using the CTAG model.

    PubMed

    Wang, Yan Jason; Yang, Bo; Lipsky, Eric M; Robinson, Allen L; Zhang, K Max

    2013-01-15

    Experimental results from laboratory emission testing have indicated that particulate emission measurements are sensitive to the dilution process of exhaust using fabricated dilution systems. In this paper, we first categorize the dilution parameters into two groups: (1) aerodynamics (e.g., mixing types, mixing enhancers, dilution ratios, residence time); and (2) mixture properties (e.g., temperature, relative humidity, particle size distributions of both raw exhaust and dilution gas). Then we employ the Comprehensive Turbulent Aerosol Dynamics and Gas Chemistry (CTAG) model to investigate the effects of those parameters on a set of particulate emission measurements comparing two dilution tunnels, i.e., a T-mixing lab dilution tunnel and a portable field dilution tunnel with a type of coaxial mixing. The turbulent flow fields and aerosol dynamics of particles are simulated inside two dilution tunnels. Particle size distributions under various dilution conditions predicted by CTAG are evaluated against the experimental data. It is found that in the area adjacent to the injection of exhaust, turbulence plays a crucial role in mixing the exhaust with the dilution air, and the strength of nucleation dominates the level of particle number concentrations. Further downstream, nucleation terminates and the growth of particles by condensation and coagulation continues. Sensitivity studies reveal that a potential unifying parameter for aerodynamics, i.e., the dilution rate of exhaust, plays an important role in new particle formation. The T-mixing lab tunnel tends to favor the nucleation due to a larger dilution rate of the exhaust than the coaxial mixing field tunnel. Our study indicates that numerical simulation tools can be potentially utilized to develop strategies to reduce the uncertainties associated with dilution samplings of emission sources. PMID:23190276

  8. 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...

  9. 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.

  10. 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.

  11. 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.

  12. Energy levels of the electrons localized over the surface of an inert film with address electrodes

    SciTech Connect

    Petrin, A. B., E-mail: a_petrin@mail.ru [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    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.

  13. Resonant holographic measurements of laser ablation plume expansion in vacuum and argon gas backgrounds

    SciTech Connect

    Lindley, R.A. [Michigan Univ., Ann Arbor, MI (United States)

    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.

  14. Dual phase MgO–ZrO 2 ceramics for use in LWR inert matrix fuel

    Microsoft Academic Search

    P. G. Medvedev; S. M. Frank; T. P. O’Holleran; M. K. Meyer

    2005-01-01

    To address the low thermal conductivity of the ZrO2-based inert matrix fuel and the instability in water of the MgO-based inert matrix fuel, the dual-phase MgO–ZrO2 ceramics are proposed as a matrix for light water reactor fuel for actinide transmutation and Pu burning. It is envisioned that in a dual-phase system MgO will act as efficient heat conductor while ZrO2

  15. Long-Range Interactions Dilute Granular Systems

    E-print Network

    Luding, Stefan

    in General . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.2 Intermolecular Forces algorithm for MD methods is developed that handles long-range forces in a computationally efficient between dissipation at contact and long-range repulsive/attractive forces in homogeneous dilute particle

  16. 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

  17. Covalent functionalization of silica surface using "inert" poly(dimethylsiloxanes).

    PubMed

    Graffius, Gabriel; Bernardoni, Frank; Fadeev, Alexander Y

    2014-12-16

    Methyl-terminated poly(dimethylsiloxanes) (PDMSs) are typically considered to be inert and not suitable for surface functionalization reactions because of the absence of readily hydrolyzable groups. Nevertheless, these siloxanes do react with silica and other oxides, producing chemically grafted organic surfaces. Known since the 1970s and then forgotten and recently rediscovered, this reaction provides a versatile yet simple method for the covalent functionalization of inorganic surfaces. In this work, we have explored the reactions of linear methyl-terminated and cyclic PDMS and bis-fluoroalkyl disiloxanes for the surface functionalization of mesoporous silica (Dpore ? 30-35 nm). The optimal reaction conditions included 24 h of contact of neat siloxane liquids and silica at 120-250 °C (depending on the siloxane). A study of the reactions of silicas with different extents of hydration demonstrated the critical role of water in facilitating the grafting of the siloxanes. The proposed reaction mechanism involved the hydrolysis of the adsorbed siloxanes by the Lewis acidic centers (presumably formed by water adsorbed onto surface defects) followed by the coupling of silanols to the surface to produce grafted siloxanes. For rigorously dehydrated silicas (calcination ?1000 °C), an alternative pathway that did not require water and involved the reaction of the siloxanes with the strained siloxane rings was also plausible. According to FTIR and chemical analysis, the reactions of bis-fluoroalkyl disiloxanes and cyclic PDMS (D3-D5) produced covalently-attached monolayer surfaces, and the reactions of high-MM methyl-terminated PDMS produced polymeric grafted silicas with a PDMS mass content of up to 50%. As evidenced by the high contact angles of ?130°/100° (adv/rec) and the negligible amount of water adsorption over the entire range of relative pressures, including saturation (p/p0 ? 1), the siloxane-grafted porous silicas show uniform, high-quality hydrophobic surfaces. An overall comparison of siloxanes with classical silane coupling agents (i.e., silanes with readily hydrolyzable functionalities such as chloro, amino, etc.) demonstrated that the reactions of siloxanes produced surfaces of similar quality and, although requiring higher temperatures, used noncorrosive, less hazardous reagents, thereby providing an environmentally benign alternative to the chemical functionalization of metal oxide surfaces. PMID:25419641

  18. Thermal conductivity and sound attenuation in dilute atomic Fermi gases

    SciTech Connect

    Braby, Matt; Chao Jingyi; Schaefer, Thomas [Physics Department, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    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.

  19. Comparison of microtiter broth dilution and agar dilution methods for susceptibility testing of Eikenella corrodens.

    PubMed

    Goldstein, E J; Cherubin, C E; Shulman, M

    1983-01-01

    Eikenella corrodens is a slow-growing, capnophilic, gram-negative rod which often grows poorly in liquid media. Consequently, the agar dilution technique is the method of choice for susceptibility testing of E. corrodens. We report a new microtiter broth dilution method for susceptibility testing of E. corrodens which compared favorably with results obtained by the agar dilution technique. Minimal bactericidal concentrations correlated well with minimal inhibitory concentrations. PMID:6338819

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

    Microsoft Academic Search

    Hakan Yilmaz; Anna Stefanopoulou

    2005-01-01

    Stringent constraints in oxides of nitrogen (NOx) and particulate emission require high levels of exhaust gas recirculation. In this paper we employ a Variable Valve Timing methodology that in steady-state achieves large levels of internal Exhaust 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)

  1. Control of charge dilution in turbocharged diesel engines via exhaust valve timing

    Microsoft Academic Search

    Hakan Yilmaz; Anna Stefanopoulou

    2003-01-01

    Stringent constraints in oxides of nitrogen (NOx) and particulate emission require high levels of exhaust gas recirculation. In this paper we employ a Variable Valve Timing methodology that in steady-state achieves large levels of internal Exhaust 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)

  2. Diffusion coefficients of fluorescent organic molecules in inert gases

    NASA Astrophysics Data System (ADS)

    Rolin, Cedric; Forrest, Stephen R.

    2013-07-01

    We use arrested-flow pulse broadening to measure the diffusion coefficients of four archetype organic semiconductors in two carrier gases, N2 and Ar, with a precision of 5%. The measurements are realized by the injection and transport of pulses of organic molecules in an organic vapor phase deposition chamber, followed by their detection using laser induced fluorescence that dynamically measures the organic concentration in the gas phase. Measurements show that the diffusivity of tris(8-hydroxyquinoline) aluminum (Alq3) in N2 and Ar varies as the square of the temperature and inversely with pressure over a large range of gas conditions. We show that classical Chapman-Enskog theory can be used to approximate the diffusivity with an accuracy that depends on the physical dimensions of the organic molecular species, with the most accurate predictions for spherical and rigid molecules such as Alq3.

  3. Free base tetraazaporphine isolated in inert gas hosts: Matrix influence on its spectroscopic and photochemical properties

    NASA Astrophysics Data System (ADS)

    Henchy, Chris; McCaffrey, John G.; Arabei, Serguei; Pavich, Tatiana; Galaup, Jean-Pierre; Shafizadeh, Niloufar; Crépin, Claudine

    2014-09-01

    The absorption, fluorescence, and excitation spectra of free base tetraazaporphine (H2TAP) trapped in Ne, N2, and Ar matrices have been recorded at cryogenic temperatures. Normal Raman spectra of H2TAP were recorded in KBr discs and predicted with density functional theory (DFT) using large basis sets calculations. The vibrational frequencies observed in the Raman Spectrum exhibit reasonable agreement with those deduced from the emission spectra, as well as with frequencies predicted from large basis set DFT computations. The upper state vibrational frequencies, obtained from highly resolved, site selected excitation spectra, are consistently lower than the ground state frequencies. This contrasts with the situation in free base phthalocyanine, where the upper state shows little changes in vibrational frequencies and geometry when compared with the ground state. Investigations of the photochemical properties of H2TAP isolated in the three matrices have been performed using the method of persistent spectral hole-burning (PSHB). This technique has been used to reveal sites corresponding to distinct N-H tautomers which were not evident in the absorption spectra. An analysis of the holes and antiholes produced with PSHB in the Qx (0-0) absorption band made it possible to identify inter-conversion of distinct host sites.

  4. 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 ...

  5. Microstructures of niobium-germanium alloys processed in inert gas in the 100 meter drop tube

    NASA Technical Reports Server (NTRS)

    Bayuzick, R. J.; Robinson, M. B.; Hofmeister, W. H.; Evans, N. D.

    1986-01-01

    The 100 meter drop tube at NASA's Marshall Space Flight Center has been used for a series of experiments with niobium-germanium alloys. These experiments were conducted with electromagnetic levitation melting in a 200 torr helium environment. Liquid alloys experienced large degrees of undercooling prior to solidification in the drop tube. Several interesting metastable structures were observed. However, the recalescence event prevented extended solid solubility of germanium in the A-15 beta phase. Liquids of eutectic composition were found to undercool in the presence of solid alpha and solid Nb5Ge3.

  6. Tritium process applications using SAES getters for purification and collection from inert gas streams

    Microsoft Academic Search

    D. H. Meikrantz; J. D. Baker; G. L. Bourne; R. J. Pawelko; R. A. Anderl; D. G. Tuggle; H. R. Maltrud

    1995-01-01

    A zirconium alloy getter-based tritium monitoring and collection system has been designed, built, and subsequently operated for three years at the Idaho National Engineering Laboratory. The system is automated to provide separation of tritium from ⁴¹Ar, collection of tritium on an hourly basis, unloading of getters for on-line tritium measurement via an ion chamber, and recollection of tritium on removable

  7. Cluster-surface impact dissociation of halogen molecules in large inert gas clusters

    Microsoft Academic Search

    Israel Schek; Joshua Jortner; Tamar Raz; R. D. Levine

    1996-01-01

    Molecular dynamics simulations of the dissociation of I2 embedded in large Arn (n = 319, 553) clusters, which impact at high velocities (? = 7–15 km s?1 1 ) on Pt surfaces, result in information on heterogeneous and homogeneous dissociation mechanisms. A broad distribution of dissociation lifetimes is exhibited, which can be attributed to prompt and retarded heterogeneous dissociation and

  8. Cluster-surface impact dissociation of halogen molecules in large inert gas clusters

    NASA Astrophysics Data System (ADS)

    Schek, Israel; Jortner, Joshua; Raz, Tamar; Levine, R. D.

    1996-07-01

    Molecular dynamics simulations of the dissociation of I 2 embedded in large Ar n ( n = 319, 553) clusters, which impact at high velocities (? = 7-15 km s -1 1 ) on Pt surfaces, result in information on heterogeneous and homogeneous dissociation mechanisms. A broad distribution of dissociation lifetimes is exhibited, which can be attributed to prompt and retarded heterogeneous dissociation and to prompt, retarded and outbound homogeneous dissociation events. The propagation of a microshock wave within a large cluster can be interrogated by the homogeneous dissociation of a chemical probe, with the velocity of the propagation of the dissociation front being close to the cluster impact velocity.

  9. Free base tetraazaporphine isolated in inert gas hosts: matrix influence on its spectroscopic and photochemical properties.

    PubMed

    Henchy, Chris; McCaffrey, John G; Arabei, Serguei; Pavich, Tatiana; Galaup, Jean-Pierre; Shafizadeh, Niloufar; Crépin, Claudine

    2014-09-28

    The absorption, fluorescence, and excitation spectra of free base tetraazaporphine (H2TAP) trapped in Ne, N2, and Ar matrices have been recorded at cryogenic temperatures. Normal Raman spectra of H2TAP were recorded in KBr discs and predicted with density functional theory (DFT) using large basis sets calculations. The vibrational frequencies observed in the Raman Spectrum exhibit reasonable agreement with those deduced from the emission spectra, as well as with frequencies predicted from large basis set DFT computations. The upper state vibrational frequencies, obtained from highly resolved, site selected excitation spectra, are consistently lower than the ground state frequencies. This contrasts with the situation in free base phthalocyanine, where the upper state shows little changes in vibrational frequencies and geometry when compared with the ground state. Investigations of the photochemical properties of H2TAP isolated in the three matrices have been performed using the method of persistent spectral hole-burning (PSHB). This technique has been used to reveal sites corresponding to distinct N-H tautomers which were not evident in the absorption spectra. An analysis of the holes and antiholes produced with PSHB in the Qx (0-0) absorption band made it possible to identify inter-conversion of distinct host sites. PMID:25273433

  10. 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.

  11. Mechanisms of inert gas impact induced interlayer mixing in metal multilayers grown by sputter deposition

    E-print Network

    Wadley, Haydn

    of Materials Science and Engineering, School of Engineering and Applied Science, University of Virginia, Charlottesville, Virginia 22903 Received 20 December 2000; accepted for publication 3 July 2001 Control being investigated for use in a class of nonvolatile magnetic ran- dom access memories.5 Both classes

  12. 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.

  13. 13-kV Ion-Extraction System Being Developed for Inert Gas Ion Engines

    NASA Technical Reports Server (NTRS)

    Rawlin, Vincent K.; Williams, George J.; Wilbur, Paul

    2002-01-01

    A high-voltage ion optics design was chosen for an assumed outer planet or interstellar precursor mission that would require a long-life, high-power, high-specific-impulse krypton ion engine. Such an engine could support energetic space missions to the outer planets or beyond. Detailed performance and lifetime analyses and several inexpensive subscale grid tests were conducted at the NASA Glenn Research Center and at the Colorado State University under a NASA Glenn grant. A subscale grid set of the selected geometry shown was tested at voltages up to 13,000 V. This yielded a krypton ion beam current that would, when scaled to a full-size 50-cm diameter, produce an ion beam with a power of 30 kW at a specific impulse over 14,000 sec. The operational ion beam focusing limits, as a function of ion current per hole, were found to impose requirements of high uniformity on the discharge chamber plasma density. A full-size set of two-grid, 50-cm-diameter titanium ion optics has been fabricated and awaits testing.

  14. 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

  15. Dilute nitride InNP quantum dots: Growth and photoluminescence mechanism

    SciTech Connect

    Kuang, Y. J. [Department of Physics, University of California, San Diego, La Jolla, California 92093 (United States); Takabayashi, K.; Kamiya, I. [Quantum Interface Laboratory, Toyota Technological Institute, Nagoya 468-8511 (Japan); Sukrittanon, S. [Material Science and Engineering Program, University of California, San Diego, La Jolla, California 92093 (United States); Pan, J. L.; Tu, C. W. [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093 (United States)

    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.

  16. Determination of Key Intermediates in Cholesterol and Bile Acid Biosynthesis by Stable Isotope Dilution Mass Spectrometry

    PubMed Central

    Yoshida, Tadashi; Honda, Akira; Miyazaki, Hiroshi; Matsuzaki, Yasushi

    2008-01-01

    For more than a decade, we have developed stable isotope dilution mass spectrometry methods to quantify key intermediates in cholesterol and bile acid biosynthesis, mevalonate and oxysterols, respectively. The methods are more sensitive and reproducible than conventional radioisotope (RI), gas-chromatography (GC) or high-performance liquid chromatography (HPLC) methods, so that they are applicable not only to samples from experimental animals but also to small amounts of human specimens. In this paper, we review the development of stable isotope dilution mass spectrometry for quantifying mevalonate and oxysterols in biological materials, and demonstrate the usefulness of this technique. PMID:19609389

  17. Determination of Vinyl Chloride at ug/l. Level in Water by Gas Chromatography

    ERIC Educational Resources Information Center

    Bellar, Thomas A.; And Others

    1976-01-01

    A quantitative method for the determination of vinyl chloride in water is presented. Vinyl chloride is transfered to the gas phase by bubbling inert gas through the water. After concentration on silica gel or Carbosieve-B, determination is by gas chromatography. Confirmation of vinyl chloride is by gas chromatography-mass spectrometry. (Author/BT)

  18. 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.

  19. Biosafe inertization of municipal solid waste incinerator residues by COSMOS technology.

    PubMed

    Guarienti, Michela; Gianoncelli, Alessandra; Bontempi, Elza; Moscoso Cardozo, Sdenka; Borgese, Laura; Zizioli, Daniela; Mitola, Stefania; Depero, Laura E; Presta, Marco

    2014-08-30

    Municipal solid waste incinerator (MSWI) residues can generate negative environmental impacts when improperly handled. The COlloidal Silica Medium to Obtain Safe inert (COSMOS) technology represents a new method to stabilize MSWI residues and to produce inert safe material. Here we report the results about aquatic biotoxicity of lixiviated MSWI fly ash and the corresponding inertized COSMOS material using a zebrafish (Danio rerio) embryo toxicity test. Quantitative assessment of waste biotoxicity included evaluation of mortality rate and of different morphological and teratogenous endpoints in zebrafish embryos exposed to tested materials from 3 to 72h post-fertilization. The results demonstrate that lixiviated MSWI fly ash exerts a dose-dependent lethal effect paralleled by dramatic morphological/teratogenous alterations and apoptotic events in the whole embryo body. Similar effects were observed following MSWI fly ash stabilization in classical concrete matrices, demonstrating that the obtained materials are not biologically safe. On the contrary, no significant mortality and developmental defects were observed in zebrafish embryos exposed to COSMOS inert solution. Our results provide the first experimental in vivo evidence that, in contrast with concrete stabilization procedure, COSMOS technology provides a biologically safe inert. PMID:25080155

  20. 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.

  1. Mossbauer effect in dilute iron alloys

    NASA Technical Reports Server (NTRS)

    Singh, J. J.

    1975-01-01

    The effects of variable concentration, x, of Aluminum, Germanium, and Lanthanum atoms in Iron lattice on various Mossbauer parameters was studied. Dilute binary alloys of (Fe-Al), (Fe-Ge), (Fe-Al) containing up to x = 2 a/o of the dilute constituent were prepared in the form of ingots and rolled to a thickness of 0.001 in. Mossbauer spectra of these targets were then studied in transmission geometry to measure changes in the hyperfine field, peak widths isomer shifts as well as the ratio of the intensities of peaks (1,6) to the intensities of peaks (2,5). It was shown that the concept of effective hyperfine structure field in very dilute alloys provides a useful means of studying the effects of progressively increasing the solute concentration on host lattice properties.

  2. 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.

  3. 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.

  4. Inert electrode composition having agent for controlling oxide growth on electrode made therefrom

    DOEpatents

    Ray, Siba P. (Plum Boro, PA)

    1986-01-01

    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 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.

  5. Activity coefficients at infinite dilution of organic solutes in the ionic liquid 1-ethyl-3-methylimidazolium methanesulfonate

    Microsoft Academic Search

    Aleš Blahut; Marek Sobota; Vladimír Dohnal; Pavel Vrbka

    2010-01-01

    Infinite dilution activity coefficients ?1? and gas–liquid partition coefficients KL of 30 selected hydrocarbons, alcohols, ketones, ethers, esters, haloalkanes, nitrogen- and sulphur-containing compounds in the ionic liquid (IL) 1-ethyl-3-methylimidazolium methanesulfonate [EMIM][MeSO3] were determined by gas–liquid chromatography at five temperatures in the range from 318.15 to 353.15K. Relative contribution of adsorption at gas–liquid interphase to the overall solute retention, as examined

  6. Adsorption of inert gases including element 118 on noble metal and inert surfaces from ab initio Dirac-Coulomb atomic calculations

    Microsoft Academic Search

    V. Pershina; A. Borschevsky; E. Eliav; U. Kaldor

    2008-01-01

    The interaction of the inert gases Rn and element 118 with various surfaces has been studied on the basis of fully relativistic ab initio Dirac-Coulomb CCSD(T) calculations of atomic properties. The calculated polarizability of element 118, 46.3 a.u., is the largest in group 18, the ionization potential is the lowest at 8.91 eV, and the estimated atomic radius is the

  7. 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.

  8. On the various forms of the energy equation for a dilute, monatomic mixture of nonreacting gases

    NASA Technical Reports Server (NTRS)

    Kennedy, Christopher A.

    1994-01-01

    In the case of gas mixtures, the governing equations become rather formidable and a complete listing of the equations in their various forms and methods to evaluate the transport coefficients is difficult to find. This paper seeks to compile common, as well as less well known, results in a single document. Various relationships between equations describing conservation of energy for a dilute, monatomic, nonreacting gas in local equilibrium are provided. The gas is treated as nonrelativistic, not subject to magnetic or electric fields, or radiative effects.

  9. 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.

  10. Three Extra Mirror or Sequential Families: Case for a Heavy Higgs Boson and Inert Doublet

    SciTech Connect

    Martinez, Homero [CEA, Saclay, DSM-IRFU-SPP (France); Melfo, Alejandra [ICTP, Trieste (Italy); Universidad de Los Andes, Merida (Venezuela, Bolivarian Republic of); Nesti, Fabrizio [Universita di Ferrara, Ferrara (Italy); Senjanovic, Goran [ICTP, Trieste (Italy)

    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}.

  11. Three Extra Mirror or Sequential Families: a Case for Heavy Higgs and Inert Doublet

    E-print Network

    Homero Martínez; Alejandra Melfo; Fabrizio Nesti; Goran Senjanovi?

    2011-04-24

    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 mass above 400\\,\\GeV, heavy new quarks between 340 and 500\\,\\GeV, light extra neutral leptons, and an inert scalar with a mass below $M_Z$.

  12. Constraining Inert Triplet dark matter by the LHC and FermiLAT

    NASA Astrophysics Data System (ADS)

    Yaser Ayazi, Seyed; Mahdi Firouzabadi, S.

    2014-11-01

    We study collider phenomenology of inert triplet scalar dark matter at the LHC. We discuss possible decay of Higgs boson to dark matter candidate and apply current experimental data for invisible Higgs decay and R?? to constrain parameter space of our model. We also investigate constraints on dark matter coming from forthcoming measurement, RZ? and mono-Higgs production. We analytically calculate the annihilation cross section of dark matter candidate into 2? and Z? and then use FermiLAT data to put constraints on parameter space of Inert Triplet Model. We found that this limit can be stronger than the constraints provided by LUX experiment for low mass DM.

  13. Three extra mirror or sequential families: case for a heavy Higgs boson and inert doublet.

    PubMed

    Martínez, Homero; Melfo, Alejandra; Nesti, Fabrizio; Senjanovi?, 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(Z). PMID:21668143

  14. Safety considerations in testing a fuel-rich aeropropulsion gas generator

    NASA Technical Reports Server (NTRS)

    Rollbuhler, R. James; Hulligan, David D.

    1991-01-01

    A catalyst containing reactor is being tested using a fuel-rich mixture of Jet A fuel and hot input air. The reactor product is a gaseous fuel that can be utilized in aeropropulsion gas turbine engines. Because the catalyst material is susceptible to damage from high temperature conditions, fuel-rich operating conditions are attained by introducing the fuel first into an inert gas stream in the reactor and then displacing the inert gas with reaction air. Once a desired fuel-to-air ratio is attained, only limited time is allowed for a catalyst induced reaction to occur; otherwise the inert gas is substituted for the air and the fuel flow is terminated. Because there presently is not a gas turbine combustor in which to burn the reactor product gas, the gas is combusted at the outlet of the test facility flare stack. This technique in operations has worked successfully in over 200 tests.

  15. Gas arc constriction for plasma arc welding

    NASA Technical Reports Server (NTRS)

    McGee, William F. (Inventor); Rybicki, Daniel J. (Inventor)

    1994-01-01

    A welding torch for plasma arc welding apparatus has an inert gas applied circumferentially about the arc column externally of the constricting nozzle so as to apply a constricting force on the arc after it has exited the nozzle orifice and downstream of the auxiliary shielding gas. The constricting inert gas is supplied to a plenum chamber about the body of the torch and exits through a series of circumferentially disposed orifices in an annular wall forming a closure at the forward end of the constricting gas plenum chamber. The constricting force of the circumferential gas flow about the arc concentrates and focuses the arc column into a more narrow and dense column of energy after exiting the nozzle orifice so that the arc better retains its energy density prior to contacting the workpiece.

  16. Sonochemical degradation of organophosphorus pesticide in dilute aqueous solutions.

    PubMed

    Farooq, Robina; Lin, Feng-Kai; Shaukat, S F; Huang, Jian-Jun

    2003-09-01

    Ultrasonic irradiation was found to accelerate the rate of hydrolysis of omethoate in aqueous solution over the pH range of 2-12. Process parameters studied include pH, steady-state temperature, concentration, and the type of gases. Greater than 96% hydrolysis was observed in 30 minutes through this process and the rate of destruction increased with the help of more soluble and low thermal inert gas. So with Krypton, omethoate was found to undergo rapid destruction as compared with Argon. In the presence of ultrasound, the observed first-order rate of hydrolysis of omethoate is found to be independent of pH. The formation of transient supercritical water (SCW) appears to be an important factor in the acceleration of chemical reactions in the presence of ultrasound. A detailed chemical reaction mechanism for omethoate destruction in water was formulated. Experimental results and theoretical kinetic mechanism demonstrated that the most of the omethoate undergo destruction inside the cavitating holes. A very less effect of temperature on the degradation of omethoate within a temperature range of 20-70 degrees C proves that a small quantity of omethoate undergoes secondary destruction in the bulk liquid. PMID:14562936

  17. Gas electron multiplier (GEM) enhanced ionization chamber for fluorescence detector

    Microsoft Academic Search

    E. H. Shaban; D. P. Siddons; A. Kuczewski

    2007-01-01

    Detecting dilute elements in thin materials using extended X-ray absorption fluorescence spectroscopy (EXAFS) method requires a detector capable of high count rate and low noise. For detection of dilute elements, the fluorescence signal amplitude is often overcome by the presence of noise or background interference. In this paper we have used a gas ionization chamber enhanced by a gas electron

  18. AN INITIAL DILUTION ZONE IMPACT ASSESSMENT

    E-print Network

    of the Fraser River Estuary Monitoring Program (FREMP) Environmental Monitoring Program. The study consisted River. A reference site was established near the FREMP water quality monitoring station at Mission#12;AN INITIAL DILUTION ZONE IMPACT ASSESSMENT OF SELECTED INDUSTRIES IN THE FRASER RIVER ESTUARY

  19. Zinc oxide based diluted magnetic semiconductors

    Microsoft Academic Search

    Shivaraman Ramachandran

    2007-01-01

    During my graduate research I have synthesized materials known as diluted magnetic semiconductors (DMS) as epitaxial thin film structures using the process of pulsed laser deposition (PLD). These materials are envisioned to be of importance in the emerging field of spintronics where the charge as well as the spin of the charge carriers can be combined to yield unique functionalities

  20. Resistance Minimum in Dilute Magnetic Alloys

    Microsoft Academic Search

    Jun Kondo

    1964-01-01

    Based on the s-d interaction model for dilute magnetic alloys we have calculated the scattering probability of the conduction electrons to the second Born approximation. Because of the dynamical character of the localized spin system, the Pauli principle should be taken into account in the intermediate states of the second order terms. Thus the effect of the Fermi sphere is

  1. Irradiated gases transferred without contamination or dilution

    NASA Technical Reports Server (NTRS)

    Bonn, J. L.; Kern, W.

    1967-01-01

    Vacuum chamber apparatus opens sealed canisters of irradiated gases and transfers the contents without contaminating the surrounding area, and without diluting or polluting the contained gases. The apparatus consists of the chamber, a valved piping manifold, and a special drill and sealed drilling access.

  2. 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…

  3. Magnetic properties of diluted magnetic semiconductors

    NASA Astrophysics Data System (ADS)

    de Jonge, W. J. M.; Swagten, H. J. M.

    1991-11-01

    A review will be given of the magnetic characteristics of diluted magnetic semiconductors and the relation with the driving exchange mechanisms. II-VI as well as IV-VI compounds will be considered. The relevance of the long-range interaction and the role of the carrier concentration will be emphasized.

  4. iFit and Light Dilution: Ultraviolet volcanic SO2 measurements under the microscope

    NASA Astrophysics Data System (ADS)

    Burton, Michael; Sawyer, Georgina

    2013-04-01

    Volcanic SO2 flux measurement systems are a staple of volcano monitoring networks, as this volcanic gas flux reflects the magma input rate into the volcano's feeding system. SO2 flux monitoring has been used since the seventies, with some notable successes at Pinatubo, Mt. St. Helens, Montserrat and Italian volcanoes. However, there are some subtle aspects of the atmospheric radiative transfer processed inherent in the technique which have been ignored for many years; or perhaps better, they have been forgotten, as these subtleties were clearly spelt out in early COSPEC papers by Millán and co-workers. Recent work by Kern et al. (2010, 2012) has re-focussed attention on the light dilution effect during SO2 plume measurements. This occurs when solar radiation is scattered into the slant column observed by a UV spectrometer or imaging system below the height of the volcanic plume, such that it has not passed through the plume. This below-plume light dilutes the SO2 absorption produced by light passing through the plume from above, apparently reducing the amount of SO2 present. Fortunately, the light dilution process leaves a signature in the shape of the SO2 absorption spectrum, due to the non-linear behaviour of absorption lines with respect to gas amount, following the Beer-Lamber law. This signature can be used to quantify the magnitude of the light dilution in real field spectra. We developed a new intensity spectrum UV fitting code called iFit that allows fitting of the light dilution signature, and applied this to examples from Stromboli and Etna. here we summarise the results from these studies and highlight the importance of this previously ignored process for quantify SO2 gas emissions from volcanoes.

  5. High-resolution gas chromatography\\/matrix isolation infrared spectrometry

    Microsoft Academic Search

    Gerald T. Reedy; Deon G. Ettinger; John F. Schneider; Sidney. Bourne

    1985-01-01

    An apparatus is described that allows the collection, within a matrix of condensed inert gas, of the effluent compounds from a high-resolution gas chromatograph. Each collected compound is contained within an area typically 0.3 mm in diameter yielding a concomitant high level of infrared spectral absorbance per nanogram of sample. Tests demonstrate the level of infrared sensitivity, the achievement of

  6. Gas flow effects on precision solder self-alignment

    Microsoft Academic Search

    Bingzhi Su; M. Gershovich; Y. C. Lee

    1997-01-01

    Self-aligning soldering technology is being developed for low cost, passive, precision optical alignments. To avoid contamination problems, the solder reflow process must use reacting or inert gas instead of chemical flux materials. Since the accuracy of these optical alignments should reach the range of a few micrometers (?m), the gas flow may affect the aligning process. Therefore, the effects of

  7. Gas flow effects on precision solder self-alignment

    Microsoft Academic Search

    Bingzhi Su; M. Gershovich; Y. C. Lee

    1997-01-01

    Self-aligning soldering technology is being developed for low cost, passive, precision optical alignments. To avoid contamination problems, a solder reflow process must use reacting or inert gas instead of chemical flux materials. Since the accuracy of these optical alignments should reach the range of a few ?m, the gas flow may affect the aligning process. Therefore, the effects of the

  8. Parameters of the equilibrium gas flow in a detonation equipment

    Microsoft Academic Search

    S. A. Zhdan; V. I. Fedenok

    1983-01-01

    The detonation method of depositing coatings is widely used. However, detonation equipment has been designed from empirical data without a detailed understanding of the process dynamics. Gas flow calculations made using the simplified assumption that the detonation products are an inert gas with a constant adiabatic parameter have resulted in theoretical product temperatures 24% higher than actual. This results in

  9. USE OF AN INERT RADIOACTIVE PARTICLE FOR MEASURING PARTICLE ACCUMULATION BY FILTER-FEEDING BIVALVE MOLLUSCS

    EPA Science Inventory

    The use of an inert, radioactively labeled microsphere as a measure of particle accumulation (filtration activity) by Mulinia lateralis (Say) and Mytilus edulis L. was evaluated. Bottom sediment plus temperature and salinity of the water were varied to induce changes in filtratio...

  10. Characterization of Zr-Fe-Cu Alloys for an Inert Matrix Fuel for Nuclear Energy Applications

    E-print Network

    Barnhart, Brian A.

    2013-08-09

    the metallurgical properties of the proposed matrix alloys. The groups of alloys were cast using a high temperature inert atmosphere furnace. The cast alloys showed the expected combination of phases with the exception of the ZrFe2 Laves phase which was predicted...

  11. Fiber optic oxygen sensor using fluorescence quenching for aircraft inerting fuel tank applications

    Microsoft Academic Search

    Allen Panahi

    2009-01-01

    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

  12. J Biol Chem . Author manuscript D-Maurocalcine, a pharmacologically inert efficient cell-penetrating peptide

    E-print Network

    Paris-Sud XI, Université de

    J Biol Chem . Author manuscript Page /1 18 D-Maurocalcine, a pharmacologically inert efficient cell characteristic pharmacological activity on ryanodine-sensitive calcium channels without affecting its cell for an excellent cell penetrating peptide: preserved structure, lack of pharmacological action, conserved vector

  13. Reactions of Nitrogen and Oxygen Surface Groups in Nanoporous Carbons under Inert and Reducing

    E-print Network

    Paris-Sud XI, Université de

    Reactions of Nitrogen and Oxygen Surface Groups in Nanoporous Carbons under Inert and Reducing of surface functional groups have an important role in controlling conversion of char nitrogen to NOx during of nitrogen surface functional groups in nanoporous carbons. Four suites of carbons, which were used as models

  14. Schizophrenia is a caused by patient’s prefrontal lobe becoming inert and inactive!

    Microsoft Academic Search

    Parveen Kumar

    2003-01-01

    I have struggled with schizophrenia throughout my life. I present the case report of my life to demonstrate that the fundamental psychopathology that caused various symptoms of schizophrenia in me was that my prefrontal lobe had become inert and inactive. Once I reactivated my prefrontal lobe by various prefrontal lobe mediated cognitive exercises, my symptoms of schizophrenia resolved. On the

  15. Method of enhanced lithiation of doped silicon carbide via high temperature annealing in an inert atmosphere

    SciTech Connect

    Hersam, Mark C.; Lipson, Albert L.; Bandyopadhyay, Sudeshna; Karmel, Hunter J; Bedzyk, Michael J

    2014-05-27

    A method for enhancing the lithium-ion capacity of a doped silicon carbide is disclosed. The method utilizes heat treating the silicon carbide in an inert atmosphere. Also disclosed are anodes for lithium-ion batteries prepared by the method.

  16. OPTIMIZATION OF INERT DUSTS USED AS GRAIN PROTECTANTS AND RESIDUAL SURFACE TREATMENTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Inert dusts such as diatomaceous earth (DE) are being advocated as natural control methods to eliminate insect infestations in stored grain, milling and processing plants, and food storage areas. However, efficacy of DE can be quite variable, depending on the specific formulation of DE, the particul...

  17. Does the Addition of Inert Gases at Constant Volume and Temperature Affect Chemical Equilibrium?

    ERIC Educational Resources Information Center

    Paiva, Joao C. M.; Goncalves, Jorge; Fonseca, Susana

    2008-01-01

    In this article we examine three approaches, leading to different conclusions, for answering the question "Does the addition of inert gases at constant volume and temperature modify the state of equilibrium?" In the first approach, the answer is yes as a result of a common students' alternative conception; the second approach, valid only for ideal…

  18. Method, Philosophy of Education and the Sphere of the Practico-Inert

    ERIC Educational Resources Information Center

    Papastephanou, Marianna

    2009-01-01

    This essay discusses a conception of the relation of philosophy to education that has come to be widely held in both general philosophy and philosophy of education. This view is approached here through the employment of Jean-Paul Sartre's notion of the "practico-inert" as the realm of consolidated social objects, part of which is the institution…

  19. “Inert” Formulation Ingredients with Activity: Toxicity of Trisiloxane Surfactant Solutions to Twospotted Spider Mites (Acari: Tetranychidae)

    Microsoft Academic Search

    R. S. Cowles; E. A. Cowles; A. M. McDermott; D. Ramoutar

    2000-01-01

    Organosilicone molecules are important surfactant ingredients used in formulating pesticides. These methylated silicones are considered inert ingredients, but their superior surfactant properties allow them to wet, and either suffocate or disrupt important physiological processes in mites and insects. Aqueous solutions of the trisiloxane surfactants Silwet L-77, Silwet 408, and Silwet 806 were bioassayed against adult female twospotted spider mites, Tetranychus

  20. Inert Doublet Dark Matter with an additional scalar singlet and 125 GeV Higgs Boson

    E-print Network

    Amit Dutta Banik; Debasish Majumdar

    2014-04-23

    In this work we consider a model for particle dark matter where an extra inert Higgs doublet and an additional scalar singlet is added to the Standard Model (SM) Lagrangian. The dark matter candidate is obtained from only the inert doublet. The stability of this one component dark matter is ensured by imposing a $Z_2$ symmetry on this additional inert doublet. The additional singlet scalar has a vacuum expectation value (VEV) and mixes with the Standard Model Higgs doublet resulting in two CP even scalars $h_1$ and $h_2$. We treat one of these scalars, $h_1$, to be consistent with the SM Higgs like boson of mass around 125 GeV reported by the LHC experiment. These two CP even scalars affect the annihilation cross-section of this inert doublet dark matter resulting in a larger dark matter mass region that satisfies the observed relic density. We also investigate the $h_1 \\rightarrow \\gamma\\gamma$ and $h_1 \\rightarrow \\gamma Z$ processes and compared these with LHC results. This is also used to constrain the dark matter parameter space in the present model. We find that the dark matter candidate in the mass region $\\frac {m_1} {2} < m_H < m_W$ GeV ($m_1 = 125$ GeV, mass of $h_1$) satisfies the recent bound from LUX direct detection experiment.