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Sample records for inert gas condensation

  1. Molecular dynamics simulations of cluster nucleation during inert gas condensation

    NASA Astrophysics Data System (ADS)

    Krasnochtchekov, Pavel; Averback, R. S.

    2005-01-01

    Molecular dynamics simulations of vapor-phase nucleation of germanium in an argon atmosphere were performed and a unexpected channel of nucleation was observed. This channel, vapor-induced cluster splitting, is important for more refractory materials since the critical nucleus size can fall below the size of a dimer. As opposed to conventional direct vapor nucleation of the dimer, which occurs by three-body collisions, cluster-splitting nucleation is a second-order reaction. The most important cluster-splitting reaction is the collision of a vapor atom and a trimer that leads to the formation of two dimers. The importance of the cluster-splitting nucleation channel relative to the direct vapor nucleation channel is observed to increase with decreasing vapor density and increasing ratio of vapor to carrier gas atoms.

  2. Structure and magnetic properties of Co-W clusters produced by inert gas condensation

    SciTech Connect

    Golkar, Farhad; Kramer, M. J.; Zhang, Y.; McCallum, R. W.; Skomski, R.; Sellmyer, D. J.; Shield, J. E.

    2012-04-01

    In this article, inert-gas condensation was used to synthesize Co-W clusters. The formation, structure, and magnetic properties of the clusters were investigated. Sub-10-nm clusters were obtained, and the structures and average sizes were strongly dependent on sputtering power. At low sputtering powers, the clusters were predominantly amorphous, while, at high sputtering power, the clusters were crystalline. X ray diffraction and transmission electron microscopy revealed clusters with hcp structure at high sputtering power. The magnetic properties were dependent on the sputtering power and temperature, with the highest coercivity of 810 Oe at 10 K for high sputtering power.

  3. Formation Mechanism of Fe Nanocubes by Magnetron Sputtering Inert Gas Condensation.

    PubMed

    Zhao, Junlei; Baibuz, Ekaterina; Vernieres, Jerome; Grammatikopoulos, Panagiotis; Jansson, Ville; Nagel, Morten; Steinhauer, Stephan; Sowwan, Mukhles; Kuronen, Antti; Nordlund, Kai; Djurabekova, Flyura

    2016-04-26

    In this work, we study the formation mechanisms of iron nanoparticles (Fe NPs) grown by magnetron sputtering inert gas condensation and emphasize the decisive kinetics effects that give rise specifically to cubic morphologies. Our experimental results, as well as computer simulations carried out by two different methods, indicate that the cubic shape of Fe NPs is explained by basic differences in the kinetic growth modes of {100} and {110} surfaces rather than surface formation energetics. Both our experimental and theoretical investigations show that the final shape is defined by the combination of the condensation temperature and the rate of atomic deposition onto the growing nanocluster. We, thus, construct a comprehensive deposition rate-temperature diagram of Fe NP shapes and develop an analytical model that predicts the temporal evolution of these properties. Combining the shape diagram and the analytical model, morphological control of Fe NPs during formation is feasible; as such, our method proposes a roadmap for experimentalists to engineer NPs of desired shapes for targeted applications. PMID:26962973

  4. Characterization of Pb₂₄Te₇₆ quantum dot thin film synthesized by inert gas condensation.

    PubMed

    Mahdy, Manal A; Mahdy, Iman A; El Zawawi, I K

    2015-01-01

    Air-stable and thermal-stable lead telluride quantum dot was successfully prepared on glass substrate by inert gas condensation (IGC) method. Argon (Ar) is the inert gas used during deposition process with a constant flow rate of 3 × 10(-3)Torr. The effect of heat-treatment process at different times was studies for structure, optical and electrical properties for nanocrystalline thin films. The structures of the as deposited and heat-treated films were investigated using grazing incident in-plane X-ray diffraction (GIIXD). The GIIXD pattern showed nanostructure face centered cubic structure of PbTe thin films. The energy dispersive X-ray analysis (EDX) of as deposited PbTe thin film was carried out and showed that the atomic ratio of Pb/Te was 24/76. The particle size of the as deposited PbTe film and after stored it in an unhumid atmosphere are 6.8 ± 0.3 nm and 7.2 ± 0.3 nm respectively as estimated form TEM image (i.e. in the same level of particle size). However, the particle size was changed to be 11.8 ± 0.3 nm after heat-treated for 5h at 473K. These particle size values of PbTe thin film are smaller than its Bohr radius. The estimated value of optical band gap Eg decreased from 1.71 eV for the as deposited film to 1.62 eV for film heat-treated (5 h at 473K). The dc electrical conductivity is increased with raising temperature in the range (303-473K) for all thin films under investigation. The deduced activation energy decreased from 0.222 eV for as deposited sample to 0.125 eV after heat-treated at 473K for 5 h. PMID:25022502

  5. Characterization of Pb24Te76 quantum dot thin film synthesized by inert gas condensation

    NASA Astrophysics Data System (ADS)

    Mahdy, Manal A.; Mahdy, Iman A.; El Zawawi, I. K.

    2015-01-01

    Air-stable and thermal-stable lead telluride quantum dot was successfully prepared on glass substrate by inert gas condensation (IGC) method. Argon (Ar) is the inert gas used during deposition process with a constant flow rate of 3 × 10-3 Torr. The effect of heat-treatment process at different times was studies for structure, optical and electrical properties for nanocrystalline thin films. The structures of the as deposited and heat-treated films were investigated using grazing incident in-plane X-ray diffraction (GIIXD). The GIIXD pattern showed nanostructure face centered cubic structure of PbTe thin films. The energy dispersive X-ray analysis (EDX) of as deposited PbTe thin film was carried out and showed that the atomic ratio of Pb/Te was 24/76. The particle size of the as deposited PbTe film and after stored it in an unhumid atmosphere are 6.8 ± 0.3 nm and 7.2 ± 0.3 nm respectively as estimated form TEM image (i.e. in the same level of particle size). However, the particle size was changed to be 11.8 ± 0.3 nm after heat-treated for 5 h at 473 K. These particle size values of PbTe thin film are smaller than its Bohr radius. The estimated value of optical band gap Eg decreased from 1.71 eV for the as deposited film to 1.62 eV for film heat-treated (5 h at 473 K). The dc electrical conductivity is increased with raising temperature in the range (303-473 K) for all thin films under investigation. The deduced activation energy decreased from 0.222 eV for as deposited sample to 0.125 eV after heat-treated at 473 K for 5 h.

  6. Size-controlled, magnetic, and core-shell nanoparticles synthesized by inert-gas condensation

    NASA Astrophysics Data System (ADS)

    Koten, Mark A.

    Interest in nanoparticles (2 to 100 nm in diameter) and clusters of atoms (0.5 to 2 nm in diameter) has heightened over the past two and a half decades on both fundamental and functional levels. Nanoparticles and clusters of atoms are an exciting branch of materials science because they do not behave like normal bulk matter, nor do they act like molecules. They can have shockingly different physical, chemical, optical, or magnetic properties from the same material at a larger scale. In the case of nanoparticles, the surface-to-volume ratio can change fundamental properties like melting temperature, binding energy, or electron affinity. The definitions of markers used to distinguish between metallic, semiconducting, and insulating bulk condensed matter, such as the band gap and polarizability, can even be blurred or confused on the nanoscale. Similarly, clusters of atoms can form in structures that are only stable at finite sizes, and do not translate to bulk condensed matter. Thermodynamics of finite systems changes dramatically in nanovolumes such as wires, rods, cubes, and spheres, which can lead to complex core-shell and onion-like nanostructures. Consequently, these changes in properties and structure have led to many new possibilities in the field of materials engineering. Inert-gas condensation (IGC) is a well-established method of producing nanoparticles that condense from the gas phase. Its first use dates back to the early 1990s, and it has been used to fabricate nanoparticles both commercially and in research and development for applications in magnetism, biomedicine, and catalysts. In this dissertation, IGC was used to produce a wide variety of nanoparticles. First, control over the size distributions of Cu nanoparticles and how it relates to the plasma properties inside the nucleation chamber was investigated. Next, the formation of phase pure WFe2 nanoparticles revealed that this Laves phase is ferromagnetic instead of non-magnetic. Finally, core-shell nanoparticles were produced using three thermodynamically different systems, which showed that IGC could be used to produce a wide variety of core-shell particles. These three projects are presented in the context of size-dependent structural and magnetic properties.

  7. Characterization of InSb Nanoparticles Synthesized Using Inert Gas Condensation

    NASA Astrophysics Data System (ADS)

    Pandya, Sneha G.; Kordesch, Martin E.

    2015-06-01

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

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

    PubMed

    Pandya, Sneha G; Kordesch, Martin E

    2015-12-01

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

  9. Molecular-dynamics study of the density scaling of inert gas condensation

    NASA Astrophysics Data System (ADS)

    Krasnochtchekov, P.; Albe, K.; Ashkenazy, Y.; Averback, R. S.

    2005-10-01

    The initial stages of vapor condensation of Ge in the presence of a cold Ar atmosphere were studied by molecular-dynamics simulations. The state variables of interest included the densities of condensing vapor and gas, the density of clusters, and the average cluster size, while the temperatures of the vapor and the clusters were separately monitored with time. Three condensation processes were explicitly identified: nucleation, monomeric growth, and cluster aggregation. Our principal finding is that both the average cluster size and the number of clusters scale with the linear dimension of the computation cell, L, and Ln, with the scaling parameter n ?4, corresponding to a reaction order of ? ?2.33. This small value of n is explained by an unexpected nucleation path involving the formation of Ge dimers via two-body collisions.

  10. Inert-Gas Condensed Co-W Nanoclusters: Formation, Structure and Magnetic Properties

    NASA Astrophysics Data System (ADS)

    Golkar-Fard, Farhad Reza

    Rare-earth permanent magnets are used extensively in numerous technical applications, e.g. wind turbines, audio speakers, and hybrid/electric vehicles. The demand and production of rare-earth permanent magnets in the world has in the past decades increased significantly. However, the decrease in export of rare-earth elements from China in recent time has led to a renewed interest in developing rare-earth free permanent magnets. Elements such as Fe and Co have potential, due to their high magnetization, to be used as hosts in rare-earth free permanent magnets but a major challenge is to increase their magnetocrystalline anisotropy constant, K1, which largely drives the coercivity. Theoretical calculations indicate that dissolving the 5d transition metal W in Fe or Co increases the magnetocrystalline anisotropy. The challenge, though, is in creating a solid solution in hcp Co or bcc Fe, which under equilibrium conditions have negligible solubility. In this dissertation, the formation, structure, and magnetic properties of sub-10 nm Co-W clusters with W content ranging from 4 to 24 atomic percent were studied. Co-W alloy clusters with extended solubility of W in hcp Co were produced by inert gas condensation. The different processing conditions such as the cooling scheme and sputtering power were found to control the structural state of the as-deposited Co-W clusters. For clusters formed in the water-cooled formation chamber, the mean size and the fraction crystalline clusters increased with increasing power, while the fraction of crystalline clusters formed in the liquid nitrogen-cooled formation chamber was not as affected by the sputtering power. For the low W content clusters, the structural characterization revealed clusters predominantly single crystalline hcp Co(W) structure, a significant extension of W solubility when compared to the equilibrium solubility, but fcc Co(W) and Co3W structures were observed in very small and large clusters, respectively. At high W content, clusters with hcp Co(W), fcc Co(W) or Co3W structures were observed. The magnetic measurements at 10 K and 300 K revealed that the coercivity, saturation magnetization and magnetocrystalline anisotropy of the clusters formed in the water-cooled formation chamber were higher than for clusters formed in the liquid nitrogen-cooled formation chamber. The coercivity and magnetocrystalline anisotropy of the clusters increased as long as W was dissolved into the hcp Co structure. With increasing fraction of Co3W and fcc Co(W) clusters, as observed in the high-W content sample, the magnetic properties deteriorated significantly. The highest coercivity and magnetocrystalline anisotropy of 893 Oe and 3.9 x 106 ergs/cm3, respectively, was obtained at 10 K for the 5 at.% W clusters sputtered at 150 W in the water-cooled formation chamber.

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  12. 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.

  13. Inert gas thrusters

    NASA Technical Reports Server (NTRS)

    Kaufman, H. R.

    1977-01-01

    Inert gases, particularly argon and xenon, are of interest as possible alternatives to the usual electric thruster propellants of mercury and cesium. Hollow cathode data were obtained for a wide range of operating conditions. Some test conditions gave plasma coupling voltages at or below the sputtering threshold, hence should permit long operating lifetimes. All observations of hollow cathode operation were consistent with a single theory of operation, in which a significant amount of the total electron emission is from localized areas within the orifice. This mode of emission is also supported by scanning electron microscope photographs that indicate local temperatures at or near the melting temperature of the tungsten tip. Experimental hollow cathode performance was correlated for two orifice diameters, three inert gas propellants, and a range of flow rates for each propellant. The basic theory for the production of doubly ionized argon and xenon was completed. Experimental measurements of the doubly ionized fraction agree with theory within about plus or minus 20 percent. High voltage isolators were studied for the propellant feed line. The breakdown voltage per segment ranged from 300 to over 500 V with argon.

  14. 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.

  15. Inert gas thrusters

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

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

  16. 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.

  17. INERT GAS SHIELD FOR WELDING

    DOEpatents

    Jones, S.O.; Daly, F.V.

    1958-10-14

    S>An inert gas shield is presented for arc-welding materials such as zirconium that tend to oxidize rapidly in air. The device comprises a rectangular metal box into which the welding electrode is introduced through a rubber diaphragm to provide flexibility. The front of the box is provided with a wlndow having a small hole through which flller metal is introduced. The box is supplied with an inert gas to exclude the atmosphere, and with cooling water to promote the solidification of the weld while in tbe inert atmosphere. A separate water-cooled copper backing bar is provided underneath the joint to be welded to contain the melt-through at the root of the joint, shielding the root of the joint with its own supply of inert gas and cooling the deposited weld metal. This device facilitates the welding of large workpieces of zirconium frequently encountered in reactor construction.

  18. 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.

  19. Welding Using Chilled-Inert-Gas Purging

    NASA Technical Reports Server (NTRS)

    Mcgee, William F.; Rybicki, Daniel J.

    1995-01-01

    Report describes study of fusion welding using chilled inert gas. Marked improvement shown in welding of aluminum using chilled helium gas. Chilling inert gas produces two additional benefits: 1) creation of ultradense inert atmosphere around welds; 2) chilled gas cools metal more quickly down to temperature at which metals not reactive.

  20. Structural characterization and X-ray analysis by Williamson-Hall method for Erbium doped Aluminum Nitride nanoparticles, synthesized using inert gas condensation technique

    NASA Astrophysics Data System (ADS)

    Pandya, Sneha G.; Corbett, Joseph P.; Jadwisienczak, Wojciech M.; Kordesch, Martin E.

    2016-05-01

    We have synthesized AlN nanoparticles (NPs) doped in-situ with Er (AlN:Er) using inert gas condensation technique. Using x-ray diffraction (XRD) peak broadening analysis with the Williamson-Hall (W-H) Uniform Deformation Model (UDM) the crystallite size of the NPs and the strain in NPs were found to be 80±38 nm and 3.07×10-3±0.9×10-3 respectively. In comparison, using the Debye-Scherrer's (DS) formula, we have inferred that the crystallite size of the NPs was 23±6 nm and the average strain was 4.3×10-3±0.4×10-3. The scanning electron microscopy images show that the NPs are spherical and have an average diameter of ∼300 nm. The crystallite size is smaller than the size of the NPs revealing their polycrystalline behavior. In addition, the NPs strain, stress and energy density were also calculated using W-H analysis combined with the Uniform Deformation Stress Model (UDSM) and the Uniform Deformation Energy Density Model (UDEDM). Suggested by the spherical geometry and polycrystalline nature of the AlN NPs, the strain computed from UDM, UDSM and UDEDM were in agreement confirming an isotropic mechanical nature of the particle. Luminescence measurements revealed the temperature dependence of the optical emission of the Er3+ ions, confirming the use of AlN:Er NPs for nano-scale temperature sensing.

  1. 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.

  2. Fast, Nonspattering Inert-Gas Welding

    NASA Technical Reports Server (NTRS)

    Gilbert, Jeffrey L.

    1991-01-01

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

  3. Inert gas effects on embryonic development.

    NASA Technical Reports Server (NTRS)

    Weiss, H. S.; Grimard, M.

    1972-01-01

    It had been found in previous investigations that hatchability of fertile chicken eggs is reduced to 50% or less of controls if incubation takes place in a low nitrogen atmosphere containing He. Although these results suggest some role for nitrogen in embryogenesis, it is possible that a requirement exists for an inert molecule closer in physical characteristics to nitrogen than is He. An investigation is conducted involving incubation at ground level pressure in a gas mixture in which the 79% inert component was either neon or argon. The effect of varying combinations of nitrogen, helium, and oxygen was also studied.

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

    NASA Astrophysics Data System (ADS)

    Ruidas, Bidhan C.; Ganguly, Somenath

    2015-07-01

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

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

    NASA Astrophysics Data System (ADS)

    Ruidas, Bidhan C.; Ganguly, Somenath

    2016-05-01

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

  6. 46 CFR 154.904 - Inert gas system: Controls.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Atmospheric Control in Cargo Containment Systems § 154.904 Inert gas system: Controls. The inert gas...

  7. Portable spectrometer monitors inert gas shield in welding process

    NASA Technical Reports Server (NTRS)

    Grove, E. L.

    1967-01-01

    Portable spectrometer using photosensitive readouts, monitors the amount of oxygen and hydrogen in the inert gas shield of a tungsten-inert gas welding process. A fiber optic bundle transmits the light from the welding arc to the spectrometer.

  8. 46 CFR 154.910 - Inert gas piping: Location.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Inert gas piping: Location. 154.910 Section 154.910... STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Atmospheric Control in Cargo Containment Systems § 154.910 Inert gas piping: Location. Inert gas piping...

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

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Inert gas system: Controls. 154.904 Section 154.904... STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Atmospheric Control in Cargo Containment Systems § 154.904 Inert gas system: Controls. The inert gas...

  10. 46 CFR 154.904 - Inert gas system: Controls.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Inert gas system: Controls. 154.904 Section 154.904... STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Atmospheric Control in Cargo Containment Systems § 154.904 Inert gas system: Controls. The inert gas...

  11. 46 CFR 154.903 - Inert gas systems: General.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Inert gas systems: General. 154.903 Section 154.903... STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Atmospheric Control in Cargo Containment Systems § 154.903 Inert gas systems: General. (a) Inert gas...

  12. 46 CFR 154.910 - Inert gas piping: Location.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Inert gas piping: Location. 154.910 Section 154.910... STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Atmospheric Control in Cargo Containment Systems § 154.910 Inert gas piping: Location. Inert gas piping...

  13. 46 CFR 154.904 - Inert gas system: Controls.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Inert gas system: Controls. 154.904 Section 154.904... STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Atmospheric Control in Cargo Containment Systems § 154.904 Inert gas system: Controls. The inert gas...

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

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Inert gas systems: General. 154.903 Section 154.903... STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Atmospheric Control in Cargo Containment Systems § 154.903 Inert gas systems: General. (a) Inert gas...

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

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Inert gas systems: General. 154.903 Section 154.903... STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Atmospheric Control in Cargo Containment Systems § 154.903 Inert gas systems: General. (a) Inert gas...

  16. 46 CFR 154.910 - Inert gas piping: Location.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Inert gas piping: Location. 154.910 Section 154.910... STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Atmospheric Control in Cargo Containment Systems § 154.910 Inert gas piping: Location. Inert gas piping...

  17. 46 CFR 147.66 - Inert gas fire extinguishing systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Inert gas fire extinguishing systems. 147.66 Section 147.66 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES HAZARDOUS SHIPS' STORES Stowage and Other Special Requirements for Particular Materials § 147.66 Inert gas fire extinguishing systems. (a) Inert gas...

  18. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Inert gas generators. 154.906 Section 154.906 Shipping... Atmospheric Control in Cargo Containment Systems § 154.906 Inert gas generators. The inert gas generator must... sample the discharge of the generator for oxygen content; and (c) Have an audible and visual alarm in...

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

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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

  20. 46 CFR 154.908 - Inert gas generator: Location.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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

  1. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Inert gas generators. 154.906 Section 154.906 Shipping... Atmospheric Control in Cargo Containment Systems § 154.906 Inert gas generators. The inert gas generator must... sample the discharge of the generator for oxygen content; and (c) Have an audible and visual alarm in...

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

    Code of Federal Regulations, 2013 CFR

    2013-10-01

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

  3. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

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

  4. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

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

  5. 46 CFR 154.908 - Inert gas generator: Location.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

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

  6. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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

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

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  8. 46 CFR 153.501 - Requirement for dry inert gas.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Requirement for dry inert gas. 153.501 Section 153.501 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS... Requirements § 153.501 Requirement for dry inert gas. When Table 1 refers to this section, an inert gas...

  9. 46 CFR 154.903 - Inert gas systems: General.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  10. 46 CFR 154.903 - Inert gas systems: General.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

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

  11. A new understanding of inert gas narcosis

    NASA Astrophysics Data System (ADS)

    Meng, Zhang; Yi, Gao; Haiping, Fang

    2016-01-01

    Anesthetics are extremely important in modern surgery to greatly reduce the patient’s pain. The understanding of anesthesia at molecular level is the preliminary step for the application of anesthetics in clinic safely and effectively. Inert gases, with low chemical activity, have been found to cause anesthesia for centuries, but the mechanism is unclear yet. In this review, we first summarize the progress of theories about general anesthesia, especially for inert gas narcosis, and then propose a new hypothesis that the aggregated rather than the dispersed inert gas molecules are the key to trigger the narcosis to explain the steep dose-response relationship of anesthesia. Project supported by the Supercomputing Center of Chinese Academy of Sciences in Beijing, China, the Shanghai Supercomputer Center, China, the National Natural Science Foundation of China (Grant Nos. 21273268, 11290164, and 11175230), the Startup Funding from Shanghai Institute of Applied Physics, Chinese Academy of Sciences (Grant No. Y290011011), “Hundred People Project” from Chinese Academy of Sciences, and “Pu-jiang Rencai Project” from Science and Technology Commission of Shanghai Municipality, China (Grant No. 13PJ1410400).

  12. Refractory metals welded or brazed with tungsten inert gas equipment

    NASA Technical Reports Server (NTRS)

    Wisner, J. P.

    1965-01-01

    Appropriate brazing metals and temperatures facilitate the welding or brazing of base metals with tungsten inert gas equipment. The highest quality bond is obtained when TIG welding is performed in an inert atmosphere.

  13. 46 CFR 153.500 - Inert gas systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... inert state by filling the vapor space with a gas that is neither reactive with the cargo nor flammable... inert condition (e.g. through tank breathing and relief valve leakage), but in no case an amount...

  14. MUNICIPAL LANDFILL GAS CONDENSATE

    EPA Science Inventory

    New regulations relative to air emissions from municipal landfills may require the installation of gas collection systems at landfills. As landfill gas (LFG) is collected, water and other vapors in the gas condense in the system or are purposely removed in the normal treatment of...

  15. 46 CFR 153.500 - Inert gas systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Inert gas systems. 153.500 Section 153.500 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Special Requirements § 153.500 Inert gas systems. When Table 1 refers to this section, a cargo containment system...

  16. 46 CFR 153.500 - Inert gas systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Inert gas systems. 153.500 Section 153.500 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Special Requirements § 153.500 Inert gas systems. When Table 1 refers to this section, a cargo containment system...

  17. 46 CFR 153.500 - Inert gas systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Inert gas systems. 153.500 Section 153.500 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Special Requirements § 153.500 Inert gas systems. When Table 1 refers to this section, a cargo containment system...

  18. Inert gas bubbles in bcc Fe

    NASA Astrophysics Data System (ADS)

    Gai, Xiao; Smith, Roger; Kenny, S. D.

    2016-03-01

    The properties of inert gas bubbles in bcc Fe is examined using a combination of static energy minimisation, molecular dynamics and barrier searching methods with empirical potentials. Static energy minimisation techniques indicate that for small Ar and Xe bubbles, the preferred gas to vacancy ratio at 0 K is about 1:1 for Ar and varies between 0.5:1 and 0.9:1 for Xe. In contrast to interstitial He atoms and small He interstitial clusters, which are highly mobile in the lattice, Ar and Xe atoms prefer to occupy substitutional sites and any interstitials present in the lattice soon displace Fe atoms and become substitutional. If a pre-existing bubble is present then there is a capture radius around a bubble which extends up to the 6th neighbour position. Collision cascades can also enlarge an existing bubble by the capture of vacancies. Ar and Xe can diffuse through the lattice through vacancy driven mechanisms but with relatively high energy barriers of 1.8 and 2.0 eV respectively. This indicates that Ar and Xe bubbles are much harder to form than bubbles of He and that such gases produced in a nuclear reaction would more likely be dispersed at substitutional sites without the help of increased temperature or radiation-driven mechanisms.

  19. 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.

  20. A sensitive image intensifier which uses inert gas

    NASA Technical Reports Server (NTRS)

    Kerns, Q. A.; Miller, H. M.

    1972-01-01

    High gain optical image intensifier utilizes inert gas cavity with copper electrodes to form electron avalanches without excessive pulse voltages. Estimated optical gain for device is two times 10 to the power of seven.

  1. 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.

  2. 46 CFR 153.501 - Requirement for dry inert gas.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Requirement for dry inert gas. 153.501 Section 153.501 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Special Requirements § 153.501 Requirement for...

  3. 46 CFR 153.501 - Requirement for dry inert gas.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Requirement for dry inert gas. 153.501 Section 153.501 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Special Requirements § 153.501 Requirement for...

  4. Nonchamber, Root-Side, Inert-Gas Purging During Welding

    NASA Technical Reports Server (NTRS)

    Mcgee, William F.; Rybicki, Daniel J.

    1995-01-01

    Improved apparatus distributes inert gas to protect against oxidation on root side of weld during welding and after welding while joint remains hot. Simple and lightweight; readily moved along weld path in synchronism with torch. Because it concentrates inert gas where needed, consumes gas at relatively low rate, and not necessary to monitor oxygen content of protective atmosphere. Apparatus does not obscure view of root side of weld. Used for full-penetration plasma-arc welding of such reactive metals as aluminum/lithium alloys and titanium.

  5. Experimental study of steam condensation on water in countercurrent flow in presence of inert gases

    NASA Astrophysics Data System (ADS)

    Bharathan, D.; Althof, J.

    1984-08-01

    Experimental results of investigating steam condensation on water in the presence of (noncondensable) inert gases at low temperatures and pressures relevant to open-cycle ocean thermal energy conversion (OTEC) systems are reported. Seven different condenser configurations were tested. The experimental data are correlated using a liquid flow fraction and a vent fraction to yield simple relationships of condenser performance over a wide range of test conditions. Performance maps and envelopes are provided for evaluating the relative merits of tested configurations. The height of transfer unit (HTU) for condensation ranges from 0.2 to 0.3 m among the various condenser geometries. Also reported are the pressure-loss coefficients for all the tested geometries.

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

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

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

  7. 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.

  8. 46 CFR 154.904 - Inert gas system: Controls.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Inert gas system: Controls. 154.904 Section 154.904 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Atmospheric Control in Cargo Containment...

  9. 46 CFR 154.910 - Inert gas piping: Location.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Inert gas piping: Location. 154.910 Section 154.910 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Atmospheric Control in Cargo Containment...

  10. Synthesis and deposition of metal nanoparticles by gas condensation process

    SciTech Connect

    Maicu, Marina Glöß, Daniel; Frach, Peter; Schmittgens, Ralph; Gerlach, Gerald; Hecker, Dominic

    2014-03-15

    In this work, the synthesis of Pt and Ag nanoparticles by means of the inert gas phase condensation of sputtered atomic vapor is presented. The process parameters (power, sputtering time, and gas flow) were varied in order to study the relationship between deposition conditions and properties of the nanoparticles such as their quantity, size, and size distribution. Moreover, the gas phase condensation process can be combined with a plasma enhanced chemical vapor deposition procedure in order to deposit nanocomposite coatings consisting of metallic nanoparticles embedded in a thin film matrix material. Selected examples of application of the generated nanoparticles and nanocomposites are discussed.

  11. Permeabilization of adhered cells using an inert gas jet.

    PubMed

    Cooper, Scott; Jonak, Paul; Chouinard-Pelletier, Guillaume; Coulombe, Sylvain; Jones, Elizabeth; Leask, Richard L

    2013-01-01

    Various cell transfection techniques exist and these can be broken down to three broad categories: viral, chemical and mechanical. This protocol describes a mechanical method to temporally permeabilize adherent cells using an inert gas jet that can facilitate the transfer of normally non-permeable macromolecules into cells. We believe this technique works by imparting shear forces on the plasma membrane of adherent cells, resulting in the temporary formation of micropores. Once these pores are created, the cells are then permeable to genetic material and other biomolecules. The mechanical forces involved do run the risk of permanently damaging or detaching cells from their substrate. There is, therefore, a narrow range of inert gas dynamics where the technique is effective. An inert gas jet has proven efficient at permeabilizing various adherent cell lines including HeLa, HEK293 and human abdominal aortic endothelial cells. This protocol is appropriate for the permeabilization of adherent cells both in vitro and, as we have demonstrated, in vivo, showing it may be used for research and potentially in future clinical applications. It also has the advantage of permeabilizing cells in a spatially restrictive manner, which could prove to be a valuable research tool. PMID:24056895

  12. Plasma induced by resonance enhanced multiphoton ionization in inert gas

    SciTech Connect

    Shneider, Mikhail N.; Zhang Zhili; Miles, Richard B.

    2007-12-15

    We present a detailed model for the evolution of resonance enhanced multiphoton ionization (REMPI) produced plasma during and after the ionizing laser pulse in inert gas (argon, as an example) at arbitrary pressures. Our theory includes the complete process of the REMPI plasma generation and losses, together with the changing gas thermodynamic parameters. The model shows that the plasma expansion follows a classical ambipolar diffusion and that gas heating results in a weak shock or acoustic wave. The gas becomes involved in the motion not only from the pressure gradient due to the heating, but also from the momentum transfer from the charged particles to gas atoms. The time dependence of the total number of electrons computed in theory matches closely with the results of coherent microwave scattering experiments.

  13. 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

  14. 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)…

  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. Laboratory scale inert gas atomizer for producing rapidly solidified powders

    NASA Astrophysics Data System (ADS)

    Korth, G. E.; Storhok, V. W.; Burch, J. V.

    An inert gas atomizer was constructed to produce rapidly solidified metal powders in batches of up to 3 kg. The atomizing tank assembly is 0.5 m in diameter x 1.8 m high. Various nozzle/crucible designs and processing parameters were evaluated for their effect on the powder product. The apparatus was used to produce tin, copper, and stainless steel powders with nozzle pressures no greater than 3 MPa and yielding spherical powders ranging from 200 to less than 1 micron. Various nozzle designs were evaluated and preliminary studies were initiated to investigate the process parameters as they pertain to the final powder product.

  17. Electroionization lasers using electron transitions in inert gas atoms

    NASA Astrophysics Data System (ADS)

    Basov, N. G.; Danilychev, V. A.; Kholin, I. V.

    1986-04-01

    Recent developments in high-power quasi-continuous-wave lasers based on electron transitions in inert gas atoms and pumped by fast electrons or by the electroionization method are reviewed. In particular, attention is given to high-pressure lasers using atomic transitions in XeI, KrI, ArI, and NeI which generate in the visible and near-infrared regions of the spectrum. The advantages of these lasers over other high-power lasers and, particularly, over the CO2 laser are examined.

  18. 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.

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

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... gas systems. An inert gas system on a tank that carries a flammable or combustible cargo must not... 46 Shipping 5 2011-10-01 2011-10-01 false Static discharges from inert gas systems. 153.462... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design...

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

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... gas systems. An inert gas system on a tank that carries a flammable or combustible cargo must not... 46 Shipping 5 2013-10-01 2013-10-01 false Static discharges from inert gas systems. 153.462... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design...

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

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... gas systems. An inert gas system on a tank that carries a flammable or combustible cargo must not... 46 Shipping 5 2010-10-01 2010-10-01 false Static discharges from inert gas systems. 153.462... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design...

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

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... gas systems. An inert gas system on a tank that carries a flammable or combustible cargo must not... 46 Shipping 5 2014-10-01 2014-10-01 false Static discharges from inert gas systems. 153.462... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design...

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

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... gas systems. An inert gas system on a tank that carries a flammable or combustible cargo must not... 46 Shipping 5 2012-10-01 2012-10-01 false Static discharges from inert gas systems. 153.462... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design...

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

    PubMed

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

    1995-03-01

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

  5. 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).

  6. 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.

  7. 3-D simulation of gases transport under condition of inert gas injection into goaf

    NASA Astrophysics Data System (ADS)

    Liu, Mao-Xi; Shi, Guo-Qing; Guo, Zhixiong; Wang, Yan-Ming; Ma, Li-Yang

    2016-02-01

    To prevent coal spontaneous combustion in mines, it is paramount to understand O2 gas distribution under condition of inert gas injection into goaf. In this study, the goaf was modeled as a 3-D porous medium based on stress distribution. The variation of O2 distribution influenced by CO2 or N2 injection was simulated based on the multi-component gases transport and the Navier-Stokes equations using Fluent. The numerical results without inert gas injection were compared with field measurements to validate the simulation model. Simulations with inert gas injection show that CO2 gas mainly accumulates at the goaf floor level; however, a notable portion of N2 gas moves upward. The evolution of the spontaneous combustion risky zone with continuous inert gas injection can be classified into three phases: slow inerting phase, rapid accelerating inerting phase, and stable inerting phase. The asphyxia zone with CO2 injection is about 1.25-2.4 times larger than that with N2 injection. The efficacy of preventing and putting out mine fires is strongly related with the inert gas injecting position. Ideal injections are located in the oxidation zone or the transitional zone between oxidation zone and heat dissipation zone.

  8. The intense VUV narrow band emission from an inert gas mixture discharge

    NASA Astrophysics Data System (ADS)

    Gerasimov, G.; Hallin, R.; Krylov, B.; Treshchalov, A.; Morozov, A.; Lissovski, A.; Zwereva, G.; Arnesen, A.

    2006-05-01

    Theoretical and experimental studies of low temperature plasmas of inert gas mixtures show a very high efficiency for energy transfer from broad vacuum ultravio let (VUV) continua to narrow spectra. The process of energy transfer can not be explained as an ordinary particle collision mechanism. Narrow band light amplification in plasmas of inert gas mixtures is discussed as a possible process of energy transfer.

  9. Simplified power processing for inert gas ion thrusters

    NASA Technical Reports Server (NTRS)

    Rawlin, V. K.; Pinero, L. R.; Hamley, J. A.

    1993-01-01

    Significant simplifications to power processors for inert gas ion thrusters in the 1 to 5 kW range have been identified. They include elimination of all but three power supplies - one each for the neutralizer, main discharge, and beam. The neutralizer and discharge power supplies would provide both cathode heating and plasma generating functions. This dual-use power supply concept was validated via integration tests with a 30 cm diameter xenon ion thruster. The beam/accelerator power supply would have positive and negative outputs to allow a single power supply to provide both functions. The discharge and beam power supplies would incorporate full-bridge inverters similar to those proven for flight-ready arcjet propulsion systems. Operation of this simplified power processing scheme at an inverter frequency of 50 kHz results in a projected power processor design with low mass and high efficiency. A 2 kW reference point design has estimated values of specific mass of 5.4 kg/kW and an efficiency of 93 percent.

  10. Visual/vestibular effects of inert gas narcosis.

    PubMed

    Hamilton, K; Laliberte, M F; Heslegrave, R; Khan, S

    1993-08-01

    Divers breathing compressed air at depths beyond 30 m experience a type of behavioural impairment known as inert gas narcosis. This condition degrades performance on a wide range of tasks and has the potential to compromise safety. Symptoms associated with narcosis include slowed response time, amnesia, and euphoria. Studies have also found disturbances to mechanisms regulating ocular control in response to vestibular stimulation; however, these experiments have been limited to very low frequency head movement (0.2 Hz). Thus, to further examine the effects of narcosis on visual/vestibular mechanisms, the vestibular ocular reflex (VOR) was assessed across a range of higher frequencies more representative of natural head movement (2.0-4.7 Hz). Seven subjects were tested prior to, during and after exposure to narcosis which was induced using 30% nitrous oxide. Standard room air was breathed as a control. The results indicated that narcosis decreased the velocity of compensatory eye movements in response to head rotation (decrease in VOR-gain), with more pronounced decreases occurring at the higher frequencies. The lag between eye and head position (phase lag) was also decreased by nitrous oxide; an effect that was again more pronounced at higher frequencies. These results indicate that narcosis disrupts ocular regulatory mechanisms which help to stabilize images on the retina during head movement. PMID:8365388

  11. Simplified power processing for inert gas ion thrusters

    NASA Astrophysics Data System (ADS)

    Rawlin, V. K.; Pinero, L. R.; Hamley, J. A.

    1993-06-01

    Significant simplifications to power processors for inert gas ion thrusters in the 1 to 5 kW range have been identified. They include elimination of all but three power supplies - one each for the neutralizer, main discharge, and beam. The neutralizer and discharge power supplies would provide both cathode heating and plasma generating functions. This dual-use power supply concept was validated via integration tests with a 30 cm diameter xenon ion thruster. The beam/accelerator power supply would have positive and negative outputs to allow a single power supply to provide both functions. The discharge and beam power supplies would incorporate full-bridge inverters similar to those proven for flight-ready arcjet propulsion systems. Operation of this simplified power processing scheme at an inverter frequency of 50 kHz results in a projected power processor design with low mass and high efficiency. A 2 kW reference point design has estimated values of specific mass of 5.4 kg/kW and an efficiency of 93 percent.

  12. Using fumarolic inert gas composition to investigate magma dynamics at Campi Flegrei (Italy)

    NASA Astrophysics Data System (ADS)

    Chiodini, G.; Caliro, S.; Paonita, A.; Cardellini, C.

    2013-12-01

    Since 2000 the Campi Flegrei caldera sited in Neapolitan area (Italy), has showed signs of reactivation, marked by ground uplift, seismic activity, compositional variations of fumarolic effluents from La Solfatara, an increase of the fumarolic activity as well as of soil CO2 fluxes. Comparing long time series of geochemical signals with ground deformation and seismicity, we show that these changes are at least partially caused by repeated injections of magmatic fluid into the hydrothermal system. The frequency of these degassing episodes has increased in the last years, causing pulsed uplift episodes and swarms of low magnitude earthquakes. We focus here in the inert gas species (CO2-He-Ar-N2) of Solfatara fumaroles which displayed in the time spectacular and persistent variation trends affecting all the monitored vents. The observed variations, which include a continuous decrease of both N2/He and N2/CO2 ratios since 1985, paralleled by an increase of He/CO2, can not be explained neither with changes in processes of boiling-condensation in the local hydrothermal system nor with changes in the mixing proportions between a magmatic vapour and hydrothermal fluids. Consequently we investigated the possibility that the trends of inert gas species are governed by changes in the conditions controlling magma degassing at depth. We applied a magma degassing model, with the most recent updates for inert gas solubilities, after to have included petrologic constraints from the ranges of melt composition and reservoir pressure at Campi Flegrei. The model simulations for mafic melts (trachybasalt and shoshonite) show a surprising agreement with the measured data. Both decompressive degassing of an ascending magma and mixing between magmatic fluids exsolved at various levels along the ascent path can explain the long-time geochemical changes. Our work highlights that, in caldera systems where the presence of hydrothermal aquifers commonly masks the magmatic signature of reactive volatiles, inert gases are the preferred species to achieve information on the dynamics and structure of the magma plumbing systems.

  13. Hepatic blood flow measurement with inert gas clearance

    SciTech Connect

    Mathie, R.T.

    1986-07-01

    Inert gas clearance has been used for 20 years to measure hepatic blood flow. Injection of a saline solution of /sup 85/Kr or /sup 133/Xe is usually made via the PV, and the resulting hepatic clearance is monitored with a Geiger-Mueller tube, scintillation crystal, or gamma camera. Complex slow components in /sup 133/Xe clearance curves, once believed to indicate a correspondingly complex hepatic microcirculation, are now considered to be caused by nonhepatic radioactivity. Normal liver is therefore believed to receive a homogeneous perfusion throughout the depth of tissue in any given region. HA blood and PV blood are normally completely mixed in the hepatic sinusoids. Macroscopic variations in tissue perfusion may exist in different lobes of the liver in both animals and man. The technique expresses flow in units of milliliters per minute per 100 g. Accurate and acceptably reproducible results have been obtained after PV injection of isotope; fast component analysis of /sup 133/Xe clearance is most appropriate, while beta detection of /sup 85/Kr yields a simple monoexponential curve. Normal hepatic blood flow in dogs and in man is 100-130 ml min-1 100 g-1. Employing sites of isotope administration other than the PV produces inaccurate results unless appropriate corrections are made. Accuracy of flow measurement is critically dependent on a knowledge of the partition coefficient of the gas used. Liver disease per se does not affect measurement accuracy, and many practical features make the technique an attractive tool for the measurement of hepatic hemodynamics in man. Nevertheless, it is essential that the investigator be aware of certain limitations of the method, and carefully apply current concepts of clearance curve analysis and interpretation, in order to derive maximum advantage.

  14. 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.

  15. Impact of airway gas exchange on the multiple inert gas elimination technique: theory.

    PubMed

    Anderson, Joseph C; Hlastala, Michael P

    2010-03-01

    The multiple inert gas elimination technique (MIGET) provides a method for estimating alveolar gas exchange efficiency. Six soluble inert gases are infused into a peripheral vein. Measurements of these gases in breath, arterial blood, and venous blood are interpreted using a mathematical model of alveolar gas exchange (MIGET model) that neglects airway gas exchange. A mathematical model describing airway and alveolar gas exchange predicts that two of these gases, ether and acetone, exchange primarily within the airways. To determine the effect of airway gas exchange on the MIGET, we selected two additional gases, toluene and m-dichlorobenzene, that have the same blood solubility as ether and acetone and minimize airway gas exchange via their low water solubility. The airway-alveolar gas exchange model simulated the exchange of toluene, m-dichlorobenzene, and the six MIGET gases under multiple conditions of alveolar ventilation-to-perfusion, VA/Q, heterogeneity. We increased the importance of airway gas exchange by changing bronchial blood flow, Qbr. From these simulations, we calculated the excretion and retention of the eight inert gases and divided the results into two groups: (1) the standard MIGET gases which included acetone and ether and (2) the modified MIGET gases which included toluene and m-dichlorobenzene. The MIGET mathematical model predicted distributions of ventilation and perfusion for each grouping of gases and multiple perturbations of VA/Q and Qbr. Using the modified MIGET gases, MIGET predicted a smaller dead space fraction, greater mean VA, greater log(SDVA), and more closely matched the imposed VA distribution than that using the standard MIGET gases. Perfusion distributions were relatively unaffected. PMID:20336837

  16. Oxygen carrier for gas chromatographic analysis of inert gases in propellants

    NASA Technical Reports Server (NTRS)

    Cannon, W. A.

    1972-01-01

    Gas chromatographic determination of small quantities of inert gases in reactive propellants is discussed. Operating conditions used for specific analyses of helium in diborane and nitrogen in oxygen difluoride are presented in tabular form.

  17. Stimulated Emission of Inert Gas Mixtures in the VUV Range

    NASA Astrophysics Data System (ADS)

    Gerasimov, G. N.; Krylov, B. E.; Hallin, R.; Morozov, A. O.; Arnesen, A.; Heijkenskjold, F.

    2002-02-01

    Amplification properties of continuous VUV emission of cooled discharge in mixtures of heavy inert gases are studied experimentally. The discharge current is 10 50 mA, the pressure is 100 GPa. Results pointing to amplification near the resonance line of xenon λ=146.96 nm are obtained. The amplification coefficient is measured to be κ=0.1 cm-1. The problem of radiation outcoupling from the active medium remains to be solved for practical implementation of a VUV laser.

  18. INVESTIGATION ON THE OSCILLATING GAS FLOW ALONG AN INERTANCE TUBE BY EXPERIMENTAL AND CFD METHODS

    SciTech Connect

    Chen Houlei; Zhao Miguang; Yang Luwei; Cai Jinghui; Hong Guotong; Liang Jingtao

    2010-04-09

    To investigate the oscillating gas flow along an inertance tube used in pulse tube coolers, a CFD model is set up for FLUENT and an experimental measuring cell is designed and optimized by CFD results. Some characteristics of oscillating flow are demonstrated and discussed. Then, the flow status along an inertance tube is measured by the optimized measuring cell. The experimental results validate the simulating results.

  19. Carbothermic Reduction of Chromite Ore Under Different Flow Rates of Inert Gas

    NASA Astrophysics Data System (ADS)

    Chakraborty, Dolly; Ranganathan, S.; Sinha, S. N.

    2010-02-01

    The reduction of chromite ore with carbon has been studied extensively in many laboratories. Inert gases have been used in these investigations to control the experimental conditions. However, little information is available in the literature on the influence of the gas flow rate on the rate of reduction. Experiments were carried out to study the influence of the flow rate of inert gas on the reducibility of chromite ore. The experiments showed that the rate of reduction increased with the increasing flow rate of argon up to an optimum flow rate. At higher flow rates, the rate of reduction decreased. The influence of the proportion of reductant on the extent of reduction depended on the rate of flow rate of inert gas. The experimental results are interpreted on the basis of a model that postulates that the mechanism of reduction changes with the flow rate of argon.

  20. The size-dependent morphology of Pd nanoclusters formed by gas condensation

    PubMed Central

    Pearmain, D.; Park, S. J.; Abdela, A.; Palmer, R. E.

    2015-01-01

    Size-selected Pd nanoclusters in the size range from 887 to 10 000 atoms were synthesized in a magnetron sputtering, inert gas condensation cluster beam source equipped with a time of flight mass filter. Their morphologies were investigated using scanning transmission electron microscopy (STEM) and shown to be strongly size-dependent. The larger clusters exhibited elongated structures, which we attribute to the aggregation, through multiple collisions, of smaller clusters during the gas phase condensation process. This was confirmed from the atomically resolved STEM images of the Pd nanoclusters, which showed smaller primary clusters with their own crystalline structures. PMID:26549633

  1. The size-dependent morphology of Pd nanoclusters formed by gas condensation

    NASA Astrophysics Data System (ADS)

    Pearmain, D.; Park, S. J.; Abdela, A.; Palmer, R. E.; Li, Z. Y.

    2015-11-01

    Size-selected Pd nanoclusters in the size range from 887 to 10 000 atoms were synthesized in a magnetron sputtering, inert gas condensation cluster beam source equipped with a time of flight mass filter. Their morphologies were investigated using scanning transmission electron microscopy (STEM) and shown to be strongly size-dependent. The larger clusters exhibited elongated structures, which we attribute to the aggregation, through multiple collisions, of smaller clusters during the gas phase condensation process. This was confirmed from the atomically resolved STEM images of the Pd nanoclusters, which showed smaller primary clusters with their own crystalline structures.

  2. The size-dependent morphology of Pd nanoclusters formed by gas condensation.

    PubMed

    Pearmain, D; Park, S J; Abdela, A; Palmer, R E; Li, Z Y

    2015-12-14

    Size-selected Pd nanoclusters in the size range from 887 to 10,000 atoms were synthesized in a magnetron sputtering, inert gas condensation cluster beam source equipped with a time of flight mass filter. Their morphologies were investigated using scanning transmission electron microscopy (STEM) and shown to be strongly size-dependent. The larger clusters exhibited elongated structures, which we attribute to the aggregation, through multiple collisions, of smaller clusters during the gas phase condensation process. This was confirmed from the atomically resolved STEM images of the Pd nanoclusters, which showed smaller primary clusters with their own crystalline structures. PMID:26549633

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

    DOEpatents

    McCormick, Steve H.; Pigott, William R.

    1997-01-01

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

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

    DOEpatents

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

    1997-12-30

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

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

    SciTech Connect

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

    1998-04-01

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

  6. Noble gas trapping by laboratory carbon condensates

    NASA Technical Reports Server (NTRS)

    Niemeyer, S.; Marti, K.

    1982-01-01

    Trapping of noble gases by carbon-rich matter was investigated by synthesizing carbon condensates in a noble gas atmosphere. Laser evaporation of a solid carbon target yielded submicron grains which proved to be efficient noble gas trappers (Xe distribution coefficients up to 13 cu cm STP/g-atm). The carbon condensates are better noble gas trappers than previously reported synthetic samples, except one, but coefficients inferred for meteoritic acid-residues are still orders of magnitude higher. The trapped noble gases are loosely bound and elementally strongly fractionated, but isotopic fractionations were not detected. Although this experiment does not simulate nebular conditions, the results support the evidence that carbon-rich phases in meteorites may be carriers of noble gases from early solar system reservoirs. The trapped elemental noble gas fractionations are remarkably similar to both those inferred for meteorites and those of planetary atmospheres for earth, Mars and Venus.

  7. Process modeling and control of inert gas atomization

    NASA Astrophysics Data System (ADS)

    Ridder, S. D.; Osella, S. A.; Espina, P. I.; Biancaniello, F. S.

    Research at the National Institute of Standards and Technology (NIST, formerly NBS) on gas atomization has focused on providing this process the ability to monitor and control particle size during atomization. Studies included gas and liquid flow imaging, gas flow modeling, real-time particle size measurement and process control. The process controller incorporates a multi-level expert system shell and a novel real-time particle size measurement sensor (incorporating an adaptive pattern recognition scheme). The modular nature of both the hardware and software design is adaptable to other particulate producing equipment.

  8. Vacuum rated flow controllers for inert gas ion engines

    NASA Technical Reports Server (NTRS)

    Pless, L. C.

    1987-01-01

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

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

    DOEpatents

    Hammond, Michael J.; Arendell, Mark W.

    1981-01-01

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

  10. Inert gas clearance from tissue by co-currently and counter-currently arranged microvessels

    PubMed Central

    Lu, Y.; Michel, C. C.

    2012-01-01

    To elucidate the clearance of dissolved inert gas from tissues, we have developed numerical models of gas transport in a cylindrical block of tissue supplied by one or two capillaries. With two capillaries, attention is given to the effects of co-current and counter-current flow on tissue gas clearance. Clearance by counter-current flow is compared with clearance by a single capillary or by two co-currently arranged capillaries. Effects of the blood velocity, solubility, and diffusivity of the gas in the tissue are investigated using parameters with physiological values. It is found that under the conditions investigated, almost identical clearances are achieved by a single capillary as by a co-current pair when the total flow per tissue volume in each unit is the same (i.e., flow velocity in the single capillary is twice that in each co-current vessel). For both co-current and counter-current arrangements, approximate linear relations exist between the tissue gas clearance rate and tissue blood perfusion rate. However, the counter-current arrangement of capillaries results in less-efficient clearance of the inert gas from tissues. Furthermore, this difference in efficiency increases at higher blood flow rates. At a given blood flow, the simple conduction-capacitance model, which has been used to estimate tissue blood perfusion rate from inert gas clearance, underestimates gas clearance rates predicted by the numerical models for single vessel or for two vessels with co-current flow. This difference is accounted for in discussion, which also considers the choice of parameters and possible effects of microvascular architecture on the interpretation of tissue inert gas clearance. PMID:22604885

  11. Drift velocities of electrons in methane-inert-gas mixtures

    NASA Astrophysics Data System (ADS)

    Foreman, L.; Kleban, P.; Schmidt, L. D.; Davis, H. T.

    1981-03-01

    The drift of electrons in mixtures of methane with argon and helium is measured with a double shutter drift tube as a function of methane composition and electric field-pressure ratio Ep. At certain concentrations, inelastic scattering by methane causes a maximum in the drift velocity as a function of Ep. As the methane mole fraction decreases, the drift velocity maximum decreases and moves to lower values of Ep. In the argon mixtures, the drift velocity at low Ep is greater than it is in either pure gas. Comparision is made with direct numerical solutions of the Boltzmann equation for the mixtures. When the methane mole fractions are appropriately chosen, the data obey roughly a scaling law relating the electron drift velocity versus Ep in a methane-argon mixture with VD versus Ep in a methane-helium mixture.

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

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  14. Green spherules from Apollo 15 - Inferences about their origin from inert gas measurements.

    NASA Technical Reports Server (NTRS)

    Lakatos, S.; Yaniv, A.; Heymann, D.

    1973-01-01

    Green spherules from the 'clod' 15426 and from fines 15421 contain about 100 times less trapped inert gases than normal bulk fines from Apollo 15. These spherules have apparently never been directly exposed to the solar wind. Spherules from other fines contain about 10 times more trapped gas than those from the 'clod.' The gas in the former is surface correlated. However, spherules from fines 15401 are exceptionally gas-poor. The trapped gases can be of solar-wind origin, but this origin requires a two-stage model for the spherules from the clods. Another possibility is that the gases were absorbed from an ambient gas phase. The trapped gases may also be assumed to represent primordial lunar gas. The composition of this gas is then similar to the 'solar' or 'unfractionated' component of gas-rich meteorites, but unlike that in most of the carbonaceous chondrites.

  15. 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.

  16. Probing Toluene and Ethylbenzene Stable Glass Formation using Inert Gas Permeation

    SciTech Connect

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

    2015-09-01

    Inert gas permeation is used to investigate the formation of stable glasses of toluene and ethylbenzene. The effect of deposition temperature (Tdep) on the kinetic stability of the vapor deposited glasses is determined using Kr desorption spectra from within sandwich layers of either toluene or ethylbenzene. The results for toluene show that the most stable glass is formed at Tdep = 0.92 Tg, although glasses with a kinetic stability within 50% of the most stable glass were found with deposition temperatures from 0.85 to 0.95 Tg. Similar results were found for ethylbenzene, which formed its most stable glass at 0.91 Tg and formed stable glasses from 0.81 to 0.96 Tg. These results are consistent with recent calorimetric studies and demonstrate that the inert gas permeation technique provides a direct method to observe the onset of molecular translation motion that accompanies the glass to supercooled liquid transition.

  17. On-line determination of pulmonary blood flow using respiratory inert gas analysis.

    PubMed

    Gan, K; Nishi, I; Chin, I; Slutsky, A S

    1993-12-01

    An inert gas analysis method has been developed to perform on-line real time determination of pulmonary blood flow using a nonrebreathing approach. This technique is based on a mathematical model describing mass balance of two inert gases which are breathed using an open gas circuit. The measurements using this method are noninvasive, easy to peform, and do not disturb normal physiological processes. As well, since data are collected on a breath-by-breath basis, it is possible to estimate other respiratory, cardiopulmonary, and metabolic parameters simultaneously in a breath-by-breath manner. Special consideration was given to developing effective data processing algorithms to minimize the influence of measurement noise and respiratory variations. Experimental studies to compare this method with other accepted techniques were conducted to validate the present technique. PMID:8125501

  18. GAS CONDENSATION IN THE GALACTIC HALO

    SciTech Connect

    Joung, M. Ryan; Bryan, Greg L.; Putman, Mary E.

    2012-02-01

    Using adaptive mesh refinement (AMR) hydrodynamic simulations of vertically stratified hot halo gas, we examine the conditions under which clouds can form and condense out of the hot halo medium to potentially fuel star formation in the gaseous disk. We find that halo clouds do not develop from linear isobaric perturbations. This is a regime where the cooling time is longer than the Brunt-Vaeisaelae time, confirming previous linear analysis. We extend the analysis into the nonlinear regime by considering mildly or strongly nonlinear perturbations with overdensities up to 100, also varying the initial height, the cloud size, and the metallicity of the gas. Here, the result depends on the ratio of cooling time to the time required to accelerate the cloud to the sound speed (similar to the dynamical time). If the ratio exceeds a critical value near unity, the cloud is accelerated without further cooling and gets disrupted by Kelvin-Helmholtz and/or Rayleigh-Taylor instabilities. If it is less than the critical value, the cloud cools and condenses before disruption. Accreting gas with overdensities of 10-20 is expected to be marginally unstable; the cooling fraction will depend on the metallicity, the size of the incoming cloud, and the distance to the galaxy. Locally enhanced overdensities within cold streams have a higher likelihood of cooling out. Our results have implications on the evolution of clouds seeded by cold accretion that are barely resolved in current cosmological hydrodynamic simulations and absorption line systems detected in galaxy halos.

  19. Physical Modeling of Slag `Eye' in an Inert Gas-Shrouded Tundish Using Dimensional Analysis

    NASA Astrophysics Data System (ADS)

    Chatterjee, Saikat; Chattopadhyay, Kinnor

    2016-02-01

    The formation of an exposed eye in the gas-stirred metallurgical vessels such as ladle or tundish is a common observation. Although gas stirring results in proper homogenization of melt composition and temperature, the resulting exposed eye leads to higher heat losses, re-oxidation of liquid steel, and formation of inclusions. Most of the previous research related to slag eye were carried out explicitly for ladles. In the present work, a large number of experiments were performed to measure the slag eye area in full scale and one-third scale water models of an inert gas-shrouded tundish under various operating conditions. Based on the polynomial regression of experimental data, and the method of dimensional analysis, correlations for diameter of gas bubbles and plume velocity were developed. Subsequently, these results were used to obtain correlations for the slag eye area, and critical gas flow rate in an inert gas-shrouded tundish in terms of the operational parameters viz., gas flow rate, thickness of the slag and melt baths, along with the physical properties of the liquids viz., kinematic viscosity and density. It was observed that the dimensionless slag eye area can be expressed in terms of dimensionless numbers such as the density ratio, Froude number, and Reynolds number.

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

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

    NASA Technical Reports Server (NTRS)

    1963-01-01

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

  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. Spark gap switch system with condensable dielectric gas

    DOEpatents

    Thayer, III, William J.

    1991-01-01

    A spark gap switch system is disclosed which is capable of operating at a high pulse rate comprising an insulated switch housing having a purging gas entrance port and a gas exit port, a pair of spaced apart electrodes each having one end thereof within the housing and defining a spark gap therebetween, an easily condensable and preferably low molecular weight insulating gas flowing through the switch housing from the housing, a heat exchanger/condenser for condensing the insulating gas after it exits from the housing, a pump for recirculating the condensed insulating gas as a liquid back to the housing, and a heater exchanger/evaporator to vaporize at least a portion of the condensed insulating gas back into a vapor prior to flowing the insulating gas back into the housing.

  4. Emission lines from condensing intracluster gas

    NASA Technical Reports Server (NTRS)

    Voit, G. Mark; Donahue, Megan; Slavin, Jonathan D.

    1994-01-01

    We present computations of the emission-line spectra produced when hot gas cools nonuniformly. During inhomogeneous cooling, soft X-ray/extreme ultraviolet radiation from 10(exp 5) to 10(exp 7) K gas photoionizes coexisting clouds that have already cooled to 10(exp 4) K. Thus, strong emission lines emerge from both the high-ionization cooling gas and embedded low-ionization knots. This mechanism, which ought to operate naturally within the sonic radii of cooling flows, can generate optical emission-line spectra similar to those observed at the centers of many clusters of galaxies thought to contain such flows. We have computed the X-ray, ultraviolet (UV), optical, and infrared (IR) emission-line fluxes expected under a variety of intracluster conditions so that the self-irradiation hypothesis can be compared thoroughly with observations. If this picture is found to be adequate, the models can also be used to measure mass flow rates and inflow velocities in the vicinities of cooling-flow nebulae and to constrain the column densities and covering factors of condensed material at the centers of these clusters.

  5. CFD simulation of water vapour condensation in the presence of non-condensable gas in vertical cylindrical condensers.

    PubMed

    Li, Jun-De

    2013-02-01

    This paper presents the simulation of the condensation of water vapour in the presence of non-condensable gas using computational fluid dynamics (CFD) for turbulent flows in a vertical cylindrical condenser tube. The simulation accounts for the turbulent flow of the gas mixture, the condenser wall and the turbulent flow of the coolant in the annular channel with no assumptions of constant wall temperature or heat flux. The condensate film is assumed to occupy a negligible volume and its effect on the condensation of the water vapour has been taken into account by imposing a set of boundary conditions. A new strategy is used to overcome the limitation of the currently available commercial CFD package to solve the simultaneous simulation of flows involving multispecies and fluids of gas and liquid in separate channels. The results from the CFD simulations are compared with the experimental results from the literature for the condensation of water vapour with air as the non-condensable gas and for inlet mass fraction of the water vapour from 0.66 to 0.98. The CFD simulation results in general agree well with the directly measured quantities and it is found that the variation of heat flux in the condenser tube is more complex than a simple polynomial curve fit. The CFD results also show that, at least for flows involving high water vapour content, the axial velocity of the gas mixture at the interface between the gas mixture and the condensate film is in general not small and cannot be neglected. PMID:24850953

  6. CFD simulation of water vapour condensation in the presence of non-condensable gas in vertical cylindrical condensers

    PubMed Central

    Li, Jun-De

    2013-01-01

    This paper presents the simulation of the condensation of water vapour in the presence of non-condensable gas using computational fluid dynamics (CFD) for turbulent flows in a vertical cylindrical condenser tube. The simulation accounts for the turbulent flow of the gas mixture, the condenser wall and the turbulent flow of the coolant in the annular channel with no assumptions of constant wall temperature or heat flux. The condensate film is assumed to occupy a negligible volume and its effect on the condensation of the water vapour has been taken into account by imposing a set of boundary conditions. A new strategy is used to overcome the limitation of the currently available commercial CFD package to solve the simultaneous simulation of flows involving multispecies and fluids of gas and liquid in separate channels. The results from the CFD simulations are compared with the experimental results from the literature for the condensation of water vapour with air as the non-condensable gas and for inlet mass fraction of the water vapour from 0.66 to 0.98. The CFD simulation results in general agree well with the directly measured quantities and it is found that the variation of heat flux in the condenser tube is more complex than a simple polynomial curve fit. The CFD results also show that, at least for flows involving high water vapour content, the axial velocity of the gas mixture at the interface between the gas mixture and the condensate film is in general not small and cannot be neglected. PMID:24850953

  7. Modelling the transient behaviour of pulsed current tungsten-inert-gas weldpools

    NASA Astrophysics Data System (ADS)

    Wu, C. S.; Zheng, W.; Wu, L.

    1999-01-01

    A three-dimensional model is established to simulate the pulsed current tungsten-inert-gas (TIG) welding process. The goal is to analyse the cyclic variation of fluid flow and heat transfer in weldpools under periodic arc heat input. To this end, an algorithm, which is capable of handling the transience, nonlinearity, multiphase and strong coupling encountered in this work, is developed. The numerical simulations demonstrate the transient behaviour of weldpools under pulsed current. Experimental data are compared with numerical results to show the effectiveness of the developed model.

  8. Three-dimensional absorption process in aqua-ammonia absorption refrigerators using helium as inert gas

    SciTech Connect

    Kouremenos, D.A.; Stegou-Sagia, A.; Antonopoulos, K.A.

    1996-12-31

    In order to eliminate the danger of a possible explosion in neutral gas NH{sub 3}/H{sub 2}O absorption refrigerators using hydrogen as the inert gas, helium can be used as a substitute. A numerical procedure is presented for the calculation of the absorption process. In previous studies the problem was simplified by considering the circular absorption tube in a vertical position with the liquid NH{sub 3}/H{sub 2}O stream being of annular cross section, thus resulting in a two-dimensional situation. In the present study the three-dimensional heat and mass transfer process is considered, in which the absorption tube is nearly horizontal and the liquid NH{sub 3}/H{sub 2}O stream has a circular meniscus cross-section. The developed procedure which is based on a finite-difference solution of the three-dimensional momentum, energy and mass transport differential equations, may be used in the design of absorbers for inert gas absorption refrigeration units. It is concluded that helium behaves similarly to hydrogen and therefore it can replace it, in order to eliminate the danger of an explosion.

  9. Contribution of multiple inert gas elimination technique to pulmonary medicine. 1. Principles and information content of the multiple inert gas elimination technique.

    PubMed Central

    Roca, J.; Wagner, P. D.

    1994-01-01

    This introductory review summarises four different aspects of the multiple inert gas elimination technique (MIGET). Firstly, the historical background that facilitated, in the mid 1970s, the development of the MIGET as a tool to obtain more information about the entire spectrum of VA/Q distribution in the lung by measuring the exchange of six gases of different solubility in trace concentrations. Its principle is based on the observation that the retention (or excretion) of any gas is dependent on the solubility (lambda) of that gas and the VA/Q distribution. A second major aspect is the analysis of the information content and limitations of the technique. During the last 15 years a substantial amount of clinical research using the MIGET has been generated by several groups around the world. The technique has been shown to be adequate in understanding the mechanisms of hypoxaemia in different forms of pulmonary disease and the effects of therapeutic interventions, but also in separately determining the quantitative role of each extrapulmonary factor on systemic arterial PO2 when they change between two conditions of MIGET measurement. This information will be extensively reviewed in the forthcoming articles of this series. Next, the different modalities of the MIGET, practical considerations involved in the measurements and the guidelines for quality control have been indicated. Finally, a section has been devoted to the analysis of available data in healthy subjects under different conditions. The lack of systematic information on the VA/Q distributions of older healthy subjects is emphasised, since it will be required to fully understand the changes brought about by diseases that affect the older population. PMID:8091330

  10. Experimental study on steam condensation with non-condensable gas in horizontal microchannels

    NASA Astrophysics Data System (ADS)

    Ma, Xuehu; Fan, Xiaoguang; Lan, Zhong; Jiang, Rui; Tao, Bai

    2013-07-01

    This paper experimentally studied steam condensation with non-condensable gas in trapezoidal microchannels. The effect of noncondensable gas on condensation two-phase flow patterns and the characteristics of heat transfer and frictional pressure drop were investigated. The visualization study results showed that the special intermittent annular flow was found in the microchannel under the condition of larger mole fraction of noncondensable gas and lower steam mass flux; the apical area of injection was much larger and the neck of injection was longer for mixture gas with lower mole fraction of noncondensable gas in comparison with pure steam condensation; meanwhile, the noncondensable gas resulted in the decrease of flow patterns transitional steam mass flux and quality. The experimental results also indicated that the frictional pressure drop increased with the increasing mole fraction of noncondensable gas when the steam mass flux was fixed. Unlike nature convective condensation heat transfer, the mole fraction of noncondensable gas had little effect on Nusselt number. Based on experimental data, the predictive correlation of Nusselt number for mixture gas condensation in microchannels was established showed good agreement with experimental data.

  11. Spinor dynamics in a partially Bose-condensed sodium gas

    NASA Astrophysics Data System (ADS)

    Fahey, Donald; Glassman, Zachary; Schwettmann, Arne; Summy, Gil; Wilson, Ryan; Tiesinga, Eite; Lett, Paul

    2015-05-01

    Spin-exchange collisions have been shown to drive coherent population oscillations of the F=1 ground state magnetic sublevels in both a sodium Bose-Einstein condensate and in a non-condensed Bose gas. We investigate the spin dynamics of a partially Bose-condensed gas where the normal and condensed fractions are nearly equal. Our experiments show population oscillations in both the thermal and condensed components, accompanied by an oscillation in the momentum distribution of the thermal gas. We present evidence of spin-oscillation-dependent cooling of the thermal component due to the transfer of atoms from the condensate and discuss the dynamics of spin-1 BEC/thermal mixtures.

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

    PubMed

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

    2015-06-01

    Recent research has witnessed rapid advances in synthesis of nanocrystals, which has led to the development of a large variety of approaches for producing nanocrystals with controlled dimensions. However, most of these techniques lack the high-throughput production. Herein, we report on a viable and robust strategy based on an inert-gas-driven microflow reactor for continuous crafting of high-quality colloidal nanocrystals. With the judicious introduction of the inert-gas driven capability, the microflow reactor provides an attractive platform for continuous production of colloidal nanocrystals in large quantities, including easily-oxidized nanocrystals. The as-synthesized nanocrystals possessed a uniform size and shape. Intriguingly, the size of nanocrystals can be effectively tailored by varying the flow rate and the precursor concentration. We envision that the microflow reactor strategy is general and offers easy access to a wide range of scalable nanocrystals for potential applications in sensors, optics, optoelectronics, solar energy conversion, batteries, photocatalysis, and electronic devices. PMID:25958783

  13. 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.

  14. The coherent evolution of a condensed bosonic gas

    NASA Astrophysics Data System (ADS)

    Walser, R.; Cooper, J.; Holland, M.

    2000-06-01

    The kinetic evolution of a condensed bosonic gas is determined by two distinct physical regimes: i.e. the coherent and nonlinear motion of the condensate immersed in a cloud of non-condensate, and on the other hand, the collisional dynamics leading towards equilibrium. In most of the present experiments that have achieved BEC with dilute atomic gases, both types of processes occur simultaneously and must be considered. Based on the quantum kinetic theory presented in Ref. [1], we have studied the coherent time-dependent evolution of a condensed bosonic gas interacting dynamically with the non-condensate. In the case of a 3-dimensional isotropic condensate, we present numerical results that illustrate the physics. In particular, we will discuss the collective excitation frequencies and the important constants of motion: energy and number. [1] R. Walser J. Williams, J. Cooper, M. Holland, Phys. Rev. A, 59, 3878 (1999)

  15. Condensation heat transfer in rotating heat pipes in the presence of a non-condensable gas

    NASA Technical Reports Server (NTRS)

    Daniels, T. C.; Medwell, J. O.; Williams, R. J.

    1977-01-01

    An analysis of condensation problems in rotating heat pipes containing vapors with different concentrations of non-condensable gases is given. In situations such as this, temperature and concentration gradients are set up in the vapor-gas mixture. There is a transport of mass due to temperature gradients accompanied by an energy transport phenomena due to a concentration gradient. A Nusselt type analysis is not suited to this type of problem; however, a boundary layer type approach has successfully been used to analyze stationary condensation systems with non-condensable gases present. The present boundary layer analysis is presented for condensation processes on the inside of a rotating heat pipe in the presence of non-condensable gases.

  16. Dynamics of water desorption from a zeolite by a heated stream of inert gas

    SciTech Connect

    Bogoslovskaya, N.S.; Ustinova, E.A.; Seballo, A.A.

    1988-05-20

    Drying of gases, such as natural gas or air, by zeolites before low-temperature separation is now widely used in the national economy. A quart-glass adsorption-desorption apparatus was constructed for experimental study of gas drying and zeolite regeneration. The existence of a zone of water condensation was confirmed as the result of laboratory experiments conducted for study of thermal desorption of water from a zeolite by hot dry air, followed by calculations with the aid of a mathematical model of this process. Good agreement was found between the results of numerical calculations and laboratory experiments.

  17. Measuring Diffusivity in Supercooled Liquid Nanoscale Films using Inert Gas Permeation: I. Kinetic Model and Scaling Methods

    SciTech Connect

    Smith, R. Scott; Matthiesen, Jesper; Kay, Bruce D.

    2010-11-07

    We describe in detail a diffusion model used to simulate inert gas transport through supercooled liquid overlayers. In recent work, the transport of the inert gas has been shown to be an effective probe of the diffusivity of supercooled liquid methanol in the experimentally challenging regime near the glass transition temperature. The model simulations accurately and quantitatively describe the inert gas permeation desorption spectra. The simulation results are used to validate universal scaling relationships between the diffusivity, overlayer thickness, and the temperature ramp rate for isothermal and temperature programmed desorption. From these scaling relationships we derive simple equations from which the diffusivity can be obtained using the peak desorption time or temperature for an isothermal or set of TPD experiments respectively without numerical simulation. The results presented here demonstrate that the permeation of gases through amorphous overlayers has the potential to be a powerful technique to obtain diffusivity data in deeply supercooled liquids.

  18. 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.

  19. Mathematical simulation of the process of condensing natural gas

    NASA Astrophysics Data System (ADS)

    Tastandieva, G. M.

    2015-01-01

    Presents a two-dimensional unsteady model of heat transfer in terms of condensation of natural gas at low temperatures. Performed calculations of the process heat and mass transfer of liquefied natural gas (LNG) storage tanks of cylindrical shape. The influence of model parameters on the nature of heat transfer. Defined temperature regimes eliminate evaporation by cooling liquefied natural gas. The obtained dependence of the mass flow rate of vapor condensation gas temperature. Identified the possibility of regulating the process of "cooling down" liquefied natural gas in terms of its partial evaporation with low cost energy.

  20. Note: development of fast heating inert gas annealing apparatus operated at atmospheric pressure.

    PubMed

    Das, S C; Majumdar, A; Shripathi, T; Hippler, R

    2012-04-01

    Here, we report the development of a simple, small, fast heating, and portable, homemade, inert gas (Ar) atmospheric annealing setup. Instead of using a conventional heating element, a commercial soldering rod having an encapsulated fast heating heater is used here. The sample holder is made of a block of stainless steel. It takes 200 s to reach 700 °C, and 10 min to cool down. The probability of oxidation or surface contamination has been examined by means of x ray photoelectron spectroscopy of virgin Cu sample after annealing at 600 °C. In addition, we compare the annealing of a hydrogenated carbon nitride film (HCN(x)) in both a conventional vacuum and our newly developed ambient Ar atmosphere setup. PMID:22559595

  1. 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.

  2. Feasibility studies of waterflooding gas-condensate reservoirs

    SciTech Connect

    Matthews, J.D.; Howes, R.I.; Hawkyard, I.R.; Fishlock, T.P.

    1988-08-01

    Preliminary results obtained from a program of experimental and theoretical studies examining the uncertainties of waterflooding gas-condensate reservoirs are reported. In spite of high trapped-gas saturations (35 to 39%), further aggravated by an unusual type of hysteresis, recoveries of gas and liquids can be increased over those obtained under natural depletion.

  3. Models estimate pressure losses in gas-condensate systems

    SciTech Connect

    Ferrini, F.; Foschi, P. ); Giacchetta, G. ); Pareschi, A.; Rimini, B. )

    1990-05-07

    The efficiency of currently available correlations for two-phase gas-condensate flows is undermined by the presence of water in these flow systems. Water radically modifies the pressure-loss mechanism. Five models have been developed for estimating the global pressure loss of such pipelines in actual operation. The results of these calculations are compared with field data which concerns different measurements relative to three lines of two-phase gas-condensate mixtures in the presence of water.

  4. Inert gas enhanced laser-assisted purification of platinum electron-beam-induced deposits

    DOE PAGESBeta

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

    2015-06-30

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

  5. Inert gas enhanced laser-assisted purification of platinum electron-beam-induced deposits

    SciTech Connect

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

    2015-06-30

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

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

    SciTech Connect

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

    2009-01-21

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

  7. Condensing Magnons in a Degenerate Ferromagnetic Spinor Bose Gas.

    PubMed

    Fang, Fang; Olf, Ryan; Wu, Shun; Kadau, Holger; Stamper-Kurn, Dan M

    2016-03-01

    We observe the quasicondensation of magnon excitations within an F=1 ^{87}Rb spinor Bose-Einstein condensed gas. Magnons are pumped into a ferromagnetically ordered gas, allowed to equilibrate to a nondegenerate distribution, and then cooled evaporatively at near-constant net longitudinal magnetization, whereupon they condense. The critical magnon number, spatial distribution, and momentum distribution indicate that magnons condense in a potential that is uniform within the volume of the ferromagnetic condensate. The macroscopic transverse magnetization produced by the degenerate magnon gas remains inhomogeneous within the ∼10  s equilibration time accessed in our experiment, and includes signatures of Mermin-Ho spin textures that appear as phase singularities in the magnon quasicondensate wave function. PMID:26991184

  8. Condensing Magnons in a Degenerate Ferromagnetic Spinor Bose Gas

    NASA Astrophysics Data System (ADS)

    Fang, Fang; Olf, Ryan; Wu, Shun; Kadau, Holger; Stamper-Kurn, Dan M.

    2016-03-01

    We observe the quasicondensation of magnon excitations within an F =1 87Rb spinor Bose-Einstein condensed gas. Magnons are pumped into a ferromagnetically ordered gas, allowed to equilibrate to a nondegenerate distribution, and then cooled evaporatively at near-constant net longitudinal magnetization, whereupon they condense. The critical magnon number, spatial distribution, and momentum distribution indicate that magnons condense in a potential that is uniform within the volume of the ferromagnetic condensate. The macroscopic transverse magnetization produced by the degenerate magnon gas remains inhomogeneous within the ˜10 s equilibration time accessed in our experiment, and includes signatures of Mermin-Ho spin textures that appear as phase singularities in the magnon quasicondensate wave function.

  9. 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.

  10. Requirements for long-life operation of inert gas hollow cathodes - Preliminary results

    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.

  11. Inert gas electric heater for elevated temperature testing of small propulsion components

    SciTech Connect

    Whitehead, J.C.; Lanning, R.K.; Evans, M.C.; Barabas, N.J.

    1992-06-25

    An electric heater for inert gas has been developed to enable safe, nontoxic, indoor, low cost testing of miniature propulsion components which operate on warm gas. High pressure helium regulated to 7 MPa (1000 psi) is passed through in 8-kW electric heating element to raise its temperature to 700{degree}C (1300 {degree}F) at mass flow rates up to 2 grams/sec. The pressure and temperature are independently adjustable to lower values, and the temperature controller rapidly varies the electric power in response to changes in flow rate, so that pulsed-flow as well as be tested. The heating element is a 3.2 mm (1/8 inch) diameter nickel alloy tube, which carries the helium internally and up to 80 amperes of electric current in its wall. A transparent polycarbonate safety shield ensures personnel safety while permitting direct visual and auditory observations. Digital displays of time, pressure, and temperatures are adjacent to the test hardware, to facillitate realtime interpretation of test results and video documentation. Equations for pressure drop, heat transfer, electrical resistance, stress, and thermal response time are presented to facillitate designing similar systems.

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

    PubMed

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

    2010-09-01

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

  13. Deliverability projection model for overpressured gas-condensate reservoirs

    SciTech Connect

    Aziz, R.M.

    1985-03-01

    During the depletion history of abnormally pressured reservoir, pressure is initially maintained by a decrease in the pore volume. The P/Z vs cumulative gas produced graph in such reservoirs shows two distinct slopes and the initial gas in place can be estimated by extrapolation of P/Z straight line after the reservoir gradient has been reduced to normal. This decrease in pore volume also results in a reduction in the effective permeability of the rock thus affecting the formation in-flow performance. In the gas-condensate reservoirs, hydrocarbon liquids drop out of the gas phase below the dewpoint pressures increasing the total liquids saturation. An increase in the liquid saturation decreases the relative permeability to gas. The paper develops a high pressure gas-condensate reservoir deliverability calculation incorporating the effect of gas permeability reduction due to a decrease in pore volume and increase in oil saturation.

  14. Semiconductor nanocrystallite formation using inert gas ambient pulsed laser ablation and its application to light-emitting devices

    NASA Astrophysics Data System (ADS)

    Yoshida, Takehito; Yamada, Yuka; Suzuki, Nobuyasu; Makino, Toshiharu; Orii, Takaaki; Onai, Seinosuke

    1999-07-01

    Pulsed laser ablation (PLA) in inert background gases can synthesize the nanoscaled silicon (Si), for studying its material properties as one of the quantum confinement effects. We report an optimized condition in Si nanocrystalline formation by the PLA in inert background gas, varying processing parameters: pulse energy and width, inert background gas pressure. The optimized process can prepare well-dispersed Si nanocrystallites without any droplets and debris. Furthermore, we investigate the influence of the processing parameters Si nanocrystallites without any droplets and debris. Furthermore, we investigate the influence of the processing parameters on transition from amorphous-like Si thin films to nanocrystallites. It was found that there is a processing window of the inert background gas pressure where the carrier confinement effects become apparent. Next, we have fabricated electroluminescent (EL), diodes with active layers of the Si nanocrystallites. The structure of the EL diodes was semitransparent platinum electrode/Si nanocrystallite layer/p-type Si/Pt electrode. We have observed visible spectra of not only green photoluminescence, but also red EL, at room temperature. Furthermore, we have found that the EL diodes showed strong nonlinear dependence of EL intensity on current density.

  15. Tungsten inert gas (TIG) welding of Ni-rich NiTi plates: functional behavior

    NASA Astrophysics Data System (ADS)

    Oliveira, J. P.; Barbosa, D.; Braz Fernandes, F. M.; Miranda, R. M.

    2016-03-01

    It is often reported that, to successfully join NiTi shape memory alloys, fusion-based processes with reduced thermal affected regions (as in laser welding) are required. This paper describes an experimental study performed on the tungsten inert gas (TIG) welding of 1.5 mm thick plates of Ni-rich NiTi. The functional behavior of the joints was assessed. The superelasticity was analyzed by cycling tests at maximum imposed strains of 4, 8 and 12% and for a total of 600 cycles, without rupture. The superelastic plateau was observed, in the stress-strain curves, 30 MPa below that of the base material. Shape-memory effect was evidenced by bending tests with full recovery of the initial shape of the welded joints. In parallel, uniaxial tensile tests of the joints showed a tensile strength of 700 MPa and an elongation to rupture of 20%. The elongation is the highest reported for fusion-welding of NiTi, including laser welding. These results can be of great interest for the wide-spread inclusion of NiTi in complex shaped components requiring welding, since TIG is not an expensive process and is simple to operate and implement in industrial environments.

  16. 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

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

    SciTech Connect

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

    1992-12-31

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

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

    SciTech Connect

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

    1986-12-01

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

  19. 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.

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

    PubMed

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

    2013-01-01

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

  1. Multiproperty empirical isotropic interatomic potentials for CH4–inert gas mixtures

    PubMed Central

    El-Kader, M.S.A.

    2012-01-01

    An approximate empirical isotropic interatomic potentials for CH4–inert gas mixtures are developed by simultaneously fitting the Exponential-Spline-Morse-Spline-van der Waals (ESMSV) potential form to viscosity, thermal conductivity, thermal diffusion factors, diffusion coefficient, interaction second pressure virial coefficient and scattering cross-section data. Quantum mechanical lineshapes of collision-induced absorption (CIA) at different temperatures for CH4–He and at T = 87 K for CH4–Ar are computed using theoretical values for overlap, octopole and hexadecapole mechanisms and interaction potential as input. Also, the quantum mechanical lineshapes of collision-induced light scattering (CILS) for the mixtures CH4–Ar and CH4–Xe at room temperature are calculated. The spectra of scattering consist essentially of an intense, purely translational component which includes scattering due to free pairs and bound dimers, and the other is due to the induced rotational scattering. These spectra have been interpreted by means of pair-polarizability terms, which arise from a long-range dipole-induced-dipole (DID) with small dispersion corrections and a short-range interaction mechanism involving higher-order dipole–quadrupole A and dipole–octopole E multipole polarizabilities. Good agreement between computed and experimental lineshapes of both absorption and scattering is obtained when the models of potential, interaction-induced dipole and polarizability components are used. PMID:25685458

  2. 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.

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

    PubMed

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

    2003-07-01

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

  4. 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.

  5. Inert Gas Buffered Milling and Particle Size Separation of μm-Scale Superconducting Precursor Powders

    SciTech Connect

    Seshadri, S.; McIntyre, P.

    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.

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

    SciTech Connect

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

    2010-08-30

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

  7. Characterization of Tungsten Inert Gas (TIG) Welding Fume Generated by Apprentice Welders.

    PubMed

    Graczyk, Halshka; Lewinski, Nastassja; Zhao, Jiayuan; Concha-Lozano, Nicolas; Riediker, Michael

    2016-03-01

    Tungsten inert gas welding (TIG) represents one of the most widely used metal joining processes in industry. Its propensity to generate a greater portion of welding fume particles at the nanoscale poses a potential occupational health hazard for workers. However, current literature lacks comprehensive characterization of TIG welding fume particles. Even less is known about welding fumes generated by welding apprentices with little experience in welding. We characterized TIG welding fume generated by apprentice welders (N = 20) in a ventilated exposure cabin. Exposure assessment was conducted for each apprentice welder at the breathing zone (BZ) inside of the welding helmet and at a near-field (NF) location, 60cm away from the welding task. We characterized particulate matter (PM4), particle number concentration and particle size, particle morphology, chemical composition, reactive oxygen species (ROS) production potential, and gaseous components. The mean particle number concentration at the BZ was 1.69E+06 particles cm(-3), with a mean geometric mean diameter of 45nm. On average across all subjects, 92% of the particle counts at the BZ were below 100nm. We observed elevated concentrations of tungsten, which was most likely due to electrode consumption. Mean ROS production potential of TIG welding fumes at the BZ exceeded average concentrations previously found in traffic-polluted air. Furthermore, ROS production potential was significantly higher for apprentices that burned their metal during their welding task. We recommend that future exposure assessments take into consideration welding performance as a potential exposure modifier for apprentice welders or welders with minimal training. PMID:26464505

  8. Characterization of Tungsten Inert Gas (TIG) Welding Fume Generated by Apprentice Welders

    PubMed Central

    Graczyk, Halshka; Lewinski, Nastassja; Zhao, Jiayuan; Concha-Lozano, Nicolas; Riediker, Michael

    2016-01-01

    Tungsten inert gas welding (TIG) represents one of the most widely used metal joining processes in industry. Its propensity to generate a greater portion of welding fume particles at the nanoscale poses a potential occupational health hazard for workers. However, current literature lacks comprehensive characterization of TIG welding fume particles. Even less is known about welding fumes generated by welding apprentices with little experience in welding. We characterized TIG welding fume generated by apprentice welders (N = 20) in a ventilated exposure cabin. Exposure assessment was conducted for each apprentice welder at the breathing zone (BZ) inside of the welding helmet and at a near-field (NF) location, 60cm away from the welding task. We characterized particulate matter (PM4), particle number concentration and particle size, particle morphology, chemical composition, reactive oxygen species (ROS) production potential, and gaseous components. The mean particle number concentration at the BZ was 1.69E+06 particles cm−3, with a mean geometric mean diameter of 45nm. On average across all subjects, 92% of the particle counts at the BZ were below 100nm. We observed elevated concentrations of tungsten, which was most likely due to electrode consumption. Mean ROS production potential of TIG welding fumes at the BZ exceeded average concentrations previously found in traffic-polluted air. Furthermore, ROS production potential was significantly higher for apprentices that burned their metal during their welding task. We recommend that future exposure assessments take into consideration welding performance as a potential exposure modifier for apprentice welders or welders with minimal training. PMID:26464505

  9. 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

  10. 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.

  11. Calorimetry of a Bose-Einstein-condensed photon gas.

    PubMed

    Damm, Tobias; Schmitt, Julian; Liang, Qi; Dung, David; Vewinger, Frank; Weitz, Martin; Klaers, Jan

    2016-01-01

    Phase transitions, as the condensation of a gas to a liquid, are often revealed by a discontinuous behaviour of thermodynamic quantities. For liquid helium, for example, a divergence of the specific heat signals the transition from the normal fluid to the superfluid state. Apart from liquid helium, determining the specific heat of a Bose gas has proven to be a challenging task, for example, for ultracold atomic Bose gases. Here we examine the thermodynamic behaviour of a trapped two-dimensional photon gas, a system that allows us to spectroscopically determine the specific heat and the entropy of a nearly ideal Bose gas from the classical high temperature to the Bose-condensed quantum regime. The critical behaviour at the phase transition is clearly revealed by a cusp singularity of the specific heat. Regarded as a test of quantum statistical mechanics, our results demonstrate a quantitative agreement with its predictions at the microscopic level. PMID:27090978

  12. Calorimetry of a Bose-Einstein-condensed photon gas

    NASA Astrophysics Data System (ADS)

    Damm, Tobias; Schmitt, Julian; Liang, Qi; Dung, David; Vewinger, Frank; Weitz, Martin; Klaers, Jan

    2016-04-01

    Phase transitions, as the condensation of a gas to a liquid, are often revealed by a discontinuous behaviour of thermodynamic quantities. For liquid helium, for example, a divergence of the specific heat signals the transition from the normal fluid to the superfluid state. Apart from liquid helium, determining the specific heat of a Bose gas has proven to be a challenging task, for example, for ultracold atomic Bose gases. Here we examine the thermodynamic behaviour of a trapped two-dimensional photon gas, a system that allows us to spectroscopically determine the specific heat and the entropy of a nearly ideal Bose gas from the classical high temperature to the Bose-condensed quantum regime. The critical behaviour at the phase transition is clearly revealed by a cusp singularity of the specific heat. Regarded as a test of quantum statistical mechanics, our results demonstrate a quantitative agreement with its predictions at the microscopic level.

  13. Calorimetry of a Bose–Einstein-condensed photon gas

    PubMed Central

    Damm, Tobias; Schmitt, Julian; Liang, Qi; Dung, David; Vewinger, Frank; Weitz, Martin; Klaers, Jan

    2016-01-01

    Phase transitions, as the condensation of a gas to a liquid, are often revealed by a discontinuous behaviour of thermodynamic quantities. For liquid helium, for example, a divergence of the specific heat signals the transition from the normal fluid to the superfluid state. Apart from liquid helium, determining the specific heat of a Bose gas has proven to be a challenging task, for example, for ultracold atomic Bose gases. Here we examine the thermodynamic behaviour of a trapped two-dimensional photon gas, a system that allows us to spectroscopically determine the specific heat and the entropy of a nearly ideal Bose gas from the classical high temperature to the Bose-condensed quantum regime. The critical behaviour at the phase transition is clearly revealed by a cusp singularity of the specific heat. Regarded as a test of quantum statistical mechanics, our results demonstrate a quantitative agreement with its predictions at the microscopic level. PMID:27090978

  14. Gas condensate reservoir characterisation for CO2 geological storage

    NASA Astrophysics Data System (ADS)

    Ivakhnenko, A. P.

    2012-04-01

    During oil and gas production hydrocarbon recovery efficiency is significantly increased by injecting miscible CO2 gas in order to displace hydrocarbons towards producing wells. This process of enhanced oil recovery (EOR) might be used for the total CO2 storage after complete hydrocarbon reservoir depletion. This kind of potential storage sites was selected for detailed studies, including generalised development study to investigate the applicability of CO2 for storages. The study is focused on compositional modelling to predict the miscibility pressures. We consider depleted gas condensate field in Kazakhstan as important target for CO2 storage and EOR. This reservoir being depleted below the dew point leads to retrograde condensate formed in the pore system. CO2 injection in the depleted gas condensate reservoirs may allow enhanced gas recovery by reservoir pressurisation and liquid re-vaporisation. In addition a number of geological and petrophysical parameters should satisfy storage requirements. Studied carbonate gas condensate and oil field has strong seal, good petrophysical parameters and already proven successful containment CO2 and sour gas in high pressure and high temperature (HPHT) conditions. The reservoir is isolated Lower Permian and Carboniferous carbonate platform covering an area of about 30 km. The reservoir contains a gas column about 1.5 km thick. Importantly, the strong massive sealing consists of the salt and shale seal. Sour gas that filled in the oil-saturated shale had an active role to form strong sealing. Two-stage hydrocarbon saturation of oil and later gas within the seal frame were accompanied by bitumen precipitation in shales forming a perfect additional seal. Field hydrocarbon production began three decades ago maintaining a strategy in full replacement of gas in order to maintain pressure of the reservoir above the dew point. This was partially due to the sour nature of the gas with CO2 content over 5%. Our models and calculations demonstrate that injection of produced and additional gas (CO2 and sour gases) is economically viable and ecologically safe. Gas injection monitoring using surface injection well head pressures and measured injected volumes demonstrates a highly effective gas injection process. Injection well head pressure response shows no increase, indicating absence of compartmentalization close to the near well bore gas injection region in reservoir. And injector pulse study shows interconnectivity across the injection region highlighting good quality reservoir across the potential CO2 injection zones. Preliminary CO2 storage potential was also estimated for this type of geological site.

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

    SciTech Connect

    MM Hall

    2006-01-31

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

  16. Industrial Research of Condensing Unit for Natural Gas Boiler House

    NASA Astrophysics Data System (ADS)

    Ziemele, Jelena; Blumberga, Dagnija; Talcis, Normunds; Laicane, Ilze

    2012-12-01

    In the course of work industrial research was carried out at the boiler plant A/S "Imanta" where a 10MW passive condensing economizer working on natural gas was installed after the 116MW water boiler. The work describes the design of the condensing economizer and wiring diagram. During the industrial experiment, the following measurements were made: the temperature of water before and after the economizer; the ambient temperature; the quantity of water passing through the economizer; heat, produced by the economizer and water boilers. The work summarizes the data from 2010-2011.

  17. Temperature variability of the last 1000 years in Antarctica from inert gas isotopes

    NASA Astrophysics Data System (ADS)

    Orsi, Anais; Landais, Amaelle; Severinghaus, Jeffrey P.

    2015-04-01

    A large effort has been made to document the climate history of the last two thousand years, but there are still substantial gaps in the Southern Hemisphere, especially at high latitudes, where the changes in the climate are the largest. These gaps limit our understanding of the most fundamental driving mechanisms of the climate. In particular, the impact of solar minima on surface temperature is not fully understood. Here, we investigate the spatial structure of multi decadal climate variability in Antarctica, assess the significance of the Little Ice Age minimum documented elsewhere. We present a 1000 year temperature record at two sites in Antarctica: WAIS Divide (79°S, 112°W, 1766 m a.s.l), and Talos Dome (72°S, 159°E, 2315 m a.s.l), reconstructed from the combination of inert gas isotopes from the ice core and borehole temperature measurements. Borehole temperature provides an absolute estimate of long-term trends, while noble gases track decadal to centennial scale changes. This method provides a temperature reconstruction that is independent of water isotopes, and allows us to improve our understanding of water isotopes as a temperature proxy, and use them to track circulation changes. We find that there is a pronounced cooling trend over the last millennium at both sites, but it is stronger in East Antarctica (Talos Dome) than West Antarctica (WAIS-D). At WAIS Divide, we find that "Little Ice Age" cold period of 1400-1800 was 0.52°C colder than the last century, and that the recent warming trend (0.23°C/decade since 1960) has past analogs about every 200 years. At Talos Dome, the pronounced cooling trend over the whole record is not visible in the water isotope record, which suggests that there is a compensation of several sources of fractionation. Overall, both records are consistent with the idea that the solar minima and persistent volcanic activity of the Little Ice Age (1400-1850 A.D.) had a significant impact on the surface temperature in Antarctica. The feedbacks amplifying the forcing were likely stronger on the East Antarctic plateau than on the more marine-influenced West Antarctica.

  18. 46 CFR 154.1848 - Inerting.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... flammable vapors are purged from the tank by inert gas before air is admitted; and (4) When gas free cargo tanks are to be filled with a flammable cargo, air is purged from the tank by inert gas until the...

  19. 46 CFR 154.1848 - Inerting.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... flammable vapors are purged from the tank by inert gas before air is admitted; and (4) When gas free cargo tanks are to be filled with a flammable cargo, air is purged from the tank by inert gas until the...

  20. 46 CFR 154.1848 - Inerting.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... flammable vapors are purged from the tank by inert gas before air is admitted; and (4) When gas free cargo tanks are to be filled with a flammable cargo, air is purged from the tank by inert gas until the...

  1. 46 CFR 154.1848 - Inerting.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... flammable vapors are purged from the tank by inert gas before air is admitted; and (4) When gas free cargo tanks are to be filled with a flammable cargo, air is purged from the tank by inert gas until the...

  2. 46 CFR 154.1848 - Inerting.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... flammable vapors are purged from the tank by inert gas before air is admitted; and (4) When gas free cargo tanks are to be filled with a flammable cargo, air is purged from the tank by inert gas until the...

  3. 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.

  4. Development of a Market Optimized Condensing Gas Water Heater

    SciTech Connect

    Peter Pescatore

    2006-01-11

    This program covered the development of a market optimized condensing gas water heater for residential applications. The intent of the program was to develop a condensing design that minimized the large initial cost premium associated with traditional condensing water heater designs. Equally important was that the considered approach utilizes design and construction methods that deliver the desired efficiency without compromising product reliability. Standard condensing water heater approaches in the marketplace utilize high cost materials such as stainless steel tanks and heat exchangers as well as expensive burner systems to achieve the higher efficiencies. The key in this program was to develop a water heater design that uses low-cost, available components and technologies to achieve higher efficiency at a modest cost premium. By doing this, the design can reduce the payback to a more reasonable length, increasing the appeal of the product to the marketplace. Condensing water heaters have been in existence for years, but have not been able to significantly penetrate the market. The issue has typically been cost. The high purchase price associated with existing condensing water heaters, sometimes as much as $2000, has been a very difficult hurdle to overcome in the marketplace. The design developed under this program has the potential to reduce the purchase price of this condensing design by as much as $1000 as compared to traditional condensing units. The condensing water heater design developed over the course of this program led to an approach that delivered the following performance attributes: 90%+ thermal efficiency; 76,000 Btu/hr input rate in a 50 gallon tank; First hour rating greater than 180 gph; Rapid recovery time; and Overall operating condition well matched to combination heat and hot water applications. Over the final three years of the program, TIAX worked very closely with A.O. Smith Water Products Company as our commercial partner to optimize the design for manufacturing. This work included the initiation of a large field testing program (over 125 units) and an in-depth reliability program intended to minimize the risks associated with a new product introduction. At the time of this report, A.O. Smith plans to introduce this product to the marketplace in the early 2006 time period.

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

    DOEpatents

    Bitensky, Mark W.; Yoshida, Tatsuro

    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.

  6. 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.

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

    PubMed

    Karthikeya Sharma, T

    2015-11-01

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

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

    PubMed Central

    Karthikeya Sharma, T.

    2014-01-01

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

  9. Cooling and condensing of sulfur and water from claus process gas

    SciTech Connect

    Palm, J. W.; Kunkel, L. V.

    1985-07-02

    The Claus process gas is cooled in a condenser to condense most of the sulfur vapor in solid form. The gas leaving the condenser is then further cooled to condense water without producing substantially any sulfur in an undesirable form. The resulting gas of reduced water content is useful in Claus reaction, particularly the low temperature Claus reaction in which the product sulfur is adsorbed on the catalyst.

  10. Thermodynamics of a trapped Bose-condensed gas

    SciTech Connect

    Giorgini, S. |; Pitaevskii, L.P. ||; Stingari, S.

    1997-10-01

    The authors investigate the thermodynamic behavior of a Bose gas interacting with repulsive forces and confined in a harmonic anisotropic trap. They develop the formalism of mean field theory for non uniform systems at finite temperature, based on the generalization of Bogoliubov theory for uniform gases. By employing the WKB semiclassical approximation for the excited states the authors derive systematic results for the temperature dependence of various thermodynamic quantities: condensate fraction, density profiles, thermal energy, specific heat and moment of inertia. Their analysis points out important differences with respect to the thermodynamic behavior of uniform Bose gases. This is mainly the consequence of a major role played by single particle states at the boundary of the condensate. The authors find that the thermal depletion of the condensate is strongly enhanced by the presence of repulsive interactions and that the critical temperature is decreased with respect to the predictions of the non-interacting model. Their work points out an important scaling behavior exhibited by the system in large N limit. Scaling permits to express all the relevant thermodynamic quantities in terms of only two parameters: the reduced temperature t=T/T{sub c}{sup 0} and the ratio between the T=0 value of the chemical potential and the critical temperature T{sub c}{sup 0} for Bose-Einstein condensation. Comparisons with first experimental results and ab-initio calculations are presented.

  11. Calculation of hydrocarbon-in-place in gas and gas-condensate reservoirs - Carbon dioxide sequestration

    USGS Publications Warehouse

    Verma, Mahendra K.

    2012-01-01

    The Energy Independence and Security Act of 2007 (Public Law 110-140) authorized the U.S. Geological Survey (USGS) to conduct a national assessment of geologic storage resources for carbon dioxide (CO2), requiring estimation of hydrocarbon-in-place volumes and formation volume factors for all the oil, gas, and gas-condensate reservoirs within the U.S. sedimentary basins. The procedures to calculate in-place volumes for oil and gas reservoirs have already been presented by Verma and Bird (2005) to help with the USGS assessment of the undiscovered resources in the National Petroleum Reserve, Alaska, but there is no straightforward procedure available for calculating in-place volumes for gas-condensate reservoirs for the carbon sequestration project. The objective of the present study is to propose a simple procedure for calculating the hydrocarbon-in-place volume of a condensate reservoir to help estimate the hydrocarbon pore volume for potential CO2 sequestration.

  12. Synthesis of Cu nanopowders by condensation from the gas phase

    NASA Astrophysics Data System (ADS)

    Chepkasov, IV; Gafner, Yu Ya; Zobov, K. V.; Batoroev, S. B.; Bardakhanov, S. P.

    2016-02-01

    In order to determine the most efficient regimes of copper nanoparticles synthesis, a series of experiments were conducted by evaporation and subsequent condensation of the raw material in an argon atmosphere. During the tests it was found that an increase of evaporation rate increases significantly the average size of the synthesized particles. However, the study of the dependence of dimensional parameters of the produced clusters on the intensity of the buffer gas flow rate has encountered significant difficulties associated because the results significantly divergent from the previously conducted experiments on the synthesis of transition metal oxides. In order to solve this contradiction the computer simulation was held of copper atoms condensation from the gas phase for the three different cooling rates and for the two final temperatures T = 373 K and T = 77 K. It was found after analysis that the rate of cooling of the gas mixture and the final temperature directly influences the number and the size of particles produced. For instance, with the 10 times of cooling rate decreases the average size of the particles obtained had increased by 2.7 times at a final temperature of 77 K and by 3.1 times at Tf = 373 K.

  13. Temperature Programmed Desorption of Quench-condensed Krypton and Acetone in Air; Selective Concentration of Ultra-trace Gas Components.

    PubMed

    Suzuki, Taku T; Sakaguchi, Isao

    2016-01-01

    Selective concentration of ultra-trace components in air-like gases has an important application in analyzing volatile organic compounds in the gas. In the present study, we examined quench-condensation of the sample gas on a ZnO substrate below 50 K followed by temperature programmed desorption (TPD) (low temperature TPD) as a selective gas concentration technique. We studied two specific gases in the normal air; krypton as an inert gas and acetone as a reactive gas. We evaluated the relationship between the operating condition of low temperature TPD and the lowest detection limit. In the case of krypton, we observed the selective concentration by exposing at 6 K followed by thermal desorption at about 60 K. On the other hand, no selectivity appeared for acetone although trace acetone was successfully concentrated. This is likely due to the solvent effect by a major component in the air, which is suggested to be water. We suggest that pre-condensation to remove the water component may improve the selectivity in the trace acetone analysis by low temperature TPD. PMID:27063719

  14. Evaluation of phase envelope on natural gas, condensate and gas hydrate

    NASA Astrophysics Data System (ADS)

    Promkotra, S.; Kangsadan, T.

    2015-03-01

    The experimentally gas hydrate are generated by condensate and natural gas. Natural gas and condensate samples are collected from a gas processing plant where is situated in the northeastern part of Thailand. Physical properties of the API gravity and density of condensate are presented in the range of 55-60° and 0.71-0.76 g/cm3. The chemical compositions of petroleum-field water are analyzed to evaluate the genesis of gas hydrate by experimental procedure. The hydrochemical compositions of petroleum-field waters are mostly the Na-Cl facies. This condition can estimate how the hydrate forms. Phase envelope of condensate is found only one phase which is liquid phase. The liquid fraction is 100% at 15°C and 101.327 kPa, with the critical pressure and temperature of 2,326 kPa and 611.5 K. However, natural gas can be separated in three phases which are vapor, liquid and solid phase with the pressure and temperature at 100 kPa and 274.2 K. The hydrate curves explicit both hydrate zone and nonhydrate zone. Phase envelope of gas hydrate from the phase diagram indicates the hydrate formation. The experimental results of hydrate form can correlate to the hydrate curve. Besides, the important factor of hydrate formation depends on impurity in the petroleum system.

  15. Physicochemical peculiarities of absorbed oil in core samples of gas condensate deposit

    NASA Astrophysics Data System (ADS)

    Mikhailov, N. N.; Ermilov, O. M.; Sechina, L. S.

    2016-01-01

    The problem of the composition of absorption hydrocarbons and liquid condensate arises in the study of gas condensate reservoirs. From the examples of the gas condensate part of the Karachaganak, Astrakhan, and Yamburg deposits, it is shown that absorption hydrocarbons (absorption oil) contain polar components with S and O atoms in molecules. The differences in the physicochemical properties of absorbed oil and precipitated liquid condensate are revealed, as are the regularities in the composition and properties of the absorbed oil and condensate. The criteria for division of absorption oil and liquid condensate are given.

  16. Nucleation and growth of Mg condensate during supersonic gas quenching

    NASA Astrophysics Data System (ADS)

    Koo, A.; Brooks, G. A.; Nagle, M.

    2008-05-01

    A one-dimensional model based on classical nucleation and growth has been developed as a diagnostic tool for predicting the impact of different process conditions and nozzle geometries on particle size distributions produced from supersonic quenching of magnesium vapours. The model was validated against experimental data for water and SF 6, showing good qualitative agreement with the data. For the cases in the study—magnesium concentration from 1 to 20 mol% and the inlet temperature varying from 1600 to 1900 K—the model predicts that 99% of the condensation is due to growth of particles nucleated during an initial high nucleation rate stage. The ultimate average particle size is therefore dependent on the magnitude of the nucleation rate during that initial stage of nucleation and to the degree of subsequent growth of those particles which are, in turn, a complex function of the conditions in the nozzle. The distribution of condensate size is somewhat sensitive to the inlet temperature of nozzle, increasing the temperature from 1600 to 1900 K increases the mean size of the condensate by 25%. The molar concentration of magnesium in the gas affects the final particle size but this does not follow a simple trend. The size distribution of particles predicted from the model is very sensitive to changes in surface tension and sticking coefficient, highlighting the need for a more rigorous treatment of these parameters.

  17. Investigation of condensed and early stage gas phase hypergolic reactions

    NASA Astrophysics Data System (ADS)

    Dennis, Jacob Daniel

    Traditional hypergolic propellant combinations, such as those used on the space shuttle orbital maneuvering system first flown in 1981, feature hydrazine based fuels and nitrogen tetroxide (NTO) based oxidizers. Despite the long history of hypergolic propellant implementation, the processes that govern hypergolic ignition are not well understood. In order to achieve ignition, condensed phase fuel and oxidizer must undergo simultaneous physical mixing and chemical reaction. This process generates heat, intermediate condensed phase species, and gas phase species, which then may continue to react and generate more heat until ignition is achieved. The process is not well understood because condensed and gas phase reactions occur rapidly, typically in less than 200 μs, on much faster timescales than traditional diagnostic methods can observe. A detailed understanding of even the gas phase chemistry is lacking, but is critical for model development. Initial research has provided confidence that a study of condensed phase hypergolic reactions is useful and possible. Results obtained using an impinging jet apparatus have shown a critical residence time of 0.3 ms is required for the reaction between monomethylhydrazine (MMH) and red fuming nitric acid (RFNA, ~85% HNO3 + 15% N2O4) to achieve conditions favorable for ignition. This critical residence time spans the time required for liquid phase reactions to occur at the fuel/oxidizer interface and can give some insight into the reaction rates for this propellant combination. Experiments performed in a forced mixing constant volume reactor have demonstrated that the chamber pressurization rate for MMH/RFNA can be significantly reduced by diluting the MMH with deionized water. This result indicates that propellant dilution can slow the chemical reaction rates to occur over observable time scales. The research described in this document consists of two efforts that contribute knowledge to the propulsion community regarding the hypergolic liquid propellant combination of MMH and RFNA or pure nitric acid. The first and most important effort focuses on furthering the understanding of condensed phase reactions between MMH and nitric acid. To accomplish this goal diluted MMH and nitric acid were studied in a Fourier transform infrared spectrometer. By tracking the generation or destruction of specific chemical species in the reacting fluid we can measure the reaction progress as a function of reactant concentration and temperature. This work provides the propulsion community with a quantitative global condensed phase reaction rate equation for MMH/nitric acid. The second effort focuses on improving understanding the recently proposed gas phase hypergolic reaction mechanisms using a streak camera based ultraviolet and visible spectrometer. The time resolution on the streak camera system allows for detailed investigation of the pre-ignition and early stage gas phase species present during the reaction between MMH and RFNA.

  18. Nucleation and growth of Nb nanoclusters during plasma gas condensation

    SciTech Connect

    Bray, K. R.; Jiao, C. Q.; DeCerbo, J. N.

    2013-06-21

    Niobium nanoclusters were produced using a plasma gas condensation process. The influence of gas flow rate, aggregation length, and source current on the nanocluster nucleation and growth were analyzed. Nanoclusters with an average diameter from 4 nm to 10 nm were produced. Cluster size and concentration were tuned by controlling the process inputs. The effects of each parameter on the nucleation zone, growth length, and residence time was examined. The parameters do not affect the cluster formation and growth independently; their influence on cluster formation can be either cumulative or competing. Examining the nucleation and growth over a wide combination of parameters provided insight into their interactions and the impact on the growth process. These results provide the opportunity for a broader understanding into the nucleation and growth of nanoclusters and some insights into how process parameters interact during deposition. This knowledge will enhance the ability to create nanoclusters with desired size dispersions.

  19. An investigation of condensation heat transfer in a closed tube containing a soluble noncondensable gas

    NASA Technical Reports Server (NTRS)

    Saaski, E. W.; Hanson, R. J.

    1976-01-01

    An exact one-dimensional condensation heat transfer model for insoluble gases has been developed and compared with experimental data. Modifications to this model to accommodate soluble gas behavior have also been accomplished, and the effects on gas front behavior demonstrated. Analytical models for condensation heat transfer are documented, and a novel optical method used for measuring gas concentration profiles is outlined.

  20. Surface Remelting Treated High Velocity arc Sprayed FeNiCrAlBRE Coating by Tungsten Inert Gas

    NASA Astrophysics Data System (ADS)

    Tian, H. L.; Wei, S. C.; Chen, Y. X.; Tong, H.; Liu, Y.; Xu, B. S.

    This study aims at evaluating the effect of the TIG (Tungsten Inert Gas) remelting treatment of self-fluxing FeNiCrAlBRE alloy coatings, formed by means of high velocity arc spraying on steel surfaces. The treated and untreated samples were subjected to comparative structural examination using scanning electron microscopes. For quantitative investigation of porosity, a computer image analyser was used. Additionally, the wear resistance and wear volume loss of the worn tracks before and after the remelting process were contrastively evaluated in details. After the sprayed coatings were treated by TIG remelting in a proper conditions, the microstructure examination of the remelted coatings showed that a change of the microstructure from lamellar to cellular structure. Also, the results show that the remelting process decrease the coating defects and make the coating more wearable.

  1. Examination of laser-triggered discharge using a virtual gas model and the similarity of its Paschen curve with those of inert gases

    SciTech Connect

    Hoshi, Y.; Yoshida, H.

    2009-09-15

    We examined laser-triggered discharge (LTD) under asymmetric electric fields in air. Upon introducing a virtual gas with npd (n=2.8-3) instead of pd in Paschen's law [Ann. Phys. Chem. 37, 69 (1889)], the results of LTD in air coincided with the Paschen curve. A Paschen curve similar to those of inert gases, i.e., Ne and He, can be obtained even in air. This implies that in LTD, the number of gas molecules between electrodes appears to be n times higher than that in air. In LTD in air, the gamma effect is presumed to be significant, similar to in inert gases.

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

    SciTech Connect

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

    2011-01-17

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

  3. Federal helium program: The reaction over an inert gas. Final report

    SciTech Connect

    Mielke, J.E.

    1996-10-09

    Helium, present in relatively high concentrations in only a few natural gas fields, is released to the atmosphere and wasted when the natural gas is burned as fuel. Government involvement in helium conservation dates to the Helium Act of 1925 which authorized the Bureau of Mines to build and operate a large-scale helium extraction and purification plant. From 1929 until 1960 the federal government was the only domestic helium producer. In 1960, Congress amended the Helium Act to provide incentives to natural gas producers for stripping natural gas of its helium, for purchase of the separated helium by the government, and for its long-term storage. With over 960 million cubic meters (34.6 billion cubic feet) of helium in government storage and a large private helium recovery industry, questions arise as to the need for either the federal helium extraction program or the federally maintained helium stockpile.

  4. 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.

  5. Effects of inert species in the gas phase in a model for the catalytic oxidation of CO

    NASA Astrophysics Data System (ADS)

    Buendía, G. M.; Rikvold, P. A.

    2012-03-01

    We study by kinetic Monte Carlo simulations the catalytic oxidation of carbon monoxide on a surface in the presence of contaminants in the gas phase. The process is simulated by a Ziff-Gulari-Barshad (ZGB) model that has been modified to include the effect of the contaminants and to eliminate an unphysical oxygen poisoned phase at very low CO partial pressures. The impurities can adsorb and desorb on the surface but otherwise remain inert. We find that if the impurities cannot desorb, no matter how small their proportion in the gas mixture, the reactive window and discontinuous transition to a CO poisoned phase at high CO pressures that characterize the original ZGB model disappear. The coverages become continuous, and once the surface has reached a steady state there is no production of CO2. This is quite different from the behavior of systems in which the surface presents a fixed percentage of impurities. When the contaminants are allowed to desorb, the reactive phase appears again for CO pressures below a value that depends on the proportion of contaminants in the gas and on their desorption rate.

  6. Quantum hydrodynamics in dilute-gas Bose-Einstein condensates

    NASA Astrophysics Data System (ADS)

    Engels, Peter

    2012-10-01

    The peculiar dynamics of superfluids are a fascinating research topic. Since the first generation of a dilute gas Bose-Einstein condensate (BEC) in 1995, quantum degenerate atomic gases have taken the investigation of quantum hydrodynamics to a new level. The atomic physics toolbox has grown tremendously and now provides unique and powerful ways to explore nonlinear quantum systems. As an example, pioneering results have recently revealed that the counterflow between two superfluids can be used as a well controlled tool to access the rich dynamics of vector systems. New structures, such as beating dark-dark solitons which only exist in multicomponent systems and have never been observed before, can now be realized in the lab for the first time. Furthermore, the field of nonlinear quantum hydrodynamics is entering new regimes by exploiting Raman dressing as a tool to directly modify the dispersion relation. This leads to the generation of spin-orbit coupled BECs, artificial gauge fields, etc. that are currently receiving tremendous interest due to their parallels to complex condensed-matter systems. Studies of quantum hydrodynamics help to develop a profound understanding of nonlinear quantum dynamics, which is not only of fundamental interest but also of eminent importance for future technological applications, e.g. in telecommunication applications using optical solitons in fibers. This talk will showcase some ``classic'' hallmark results and highlight recent advances from the forefront of the field.

  7. 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.

  8. Fractional ventilation mapping using inert fluorinated gas MRI in rat models of inflammation and fibrosis.

    PubMed

    Couch, Marcus J; Fox, Matthew S; Viel, Chris; Gajawada, Gowtham; Li, Tao; Ouriadov, Alexei V; Albert, Mitchell S

    2016-05-01

    The purpose of this study was to extend established methods for fractional ventilation mapping using (19) F MRI of inert fluorinated gases to rat models of pulmonary inflammation and fibrosis. In this study, five rats were instilled with lipopolysaccharide (LPS) in the lungs two days prior to imaging, six rats were instilled with bleomycin in the lungs two weeks prior to imaging and an additional four rats were used as controls. (19) F MR lung imaging was performed at 3 T with rats continuously breathing a mixture of sulfur hexafluoride and O2 . Fractional ventilation maps were obtained using a wash-out approach, by switching the breathing mixture to pure O2 , and acquiring images following each successive wash-out breath. The mean fractional ventilation (r) was 0.29 ± 0.05 for control rats, 0.23 ± 0.10 for LPS-instilled rats and 0.19 ± 0.03 for bleomycin-instilled rats. Bleomycin-instilled rats had a significantly decreased mean r value compared with controls (P = 0.010). Although LPS-instilled rats had a slightly reduced mean r value, this trend was not statistically significant (P = 0.556). Fractional ventilation gradients were calculated in the anterior/posterior (A/P) direction, and the mean A/P gradient was -0.005 ± 0.008 cm(-1) for control rats, 0.013 ± 0.005 cm(-1) for LPS-instilled rats and 0.009 ± 0.018 cm(-1) for bleomycin-instilled rats. Fractional ventilation gradients were significantly different for control rats compared with LPS-instilled rats only (P = 0.016). The ventilation gradients calculated from control rats showed the expected gravitational relationship, while ventilation gradients calculated from LPS- and bleomycin-instilled rats showed the opposite trend. Histology confirmed that LPS-instilled rats had a significantly elevated alveolar wall thickness, while bleomycin-instilled rats showed signs of substantial fibrosis. Overall, (19) F MRI may be able to detect the effects of pulmonary inflammation and fibrosis using a simple and inexpensive imaging approach that can potentially be translated to humans. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26866511

  9. 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...

  10. Assessment of the biological effects of welding fumes emitted from metal inert gas welding processes of aluminium and zinc-plated materials in humans.

    PubMed

    Hartmann, L; Bauer, M; Bertram, J; Gube, M; Lenz, K; Reisgen, U; Schettgen, T; Kraus, T; Brand, P

    2014-03-01

    The aim of this study was to investigate biological effects and potential health risks due to two different metal-inert-gas (MIG) welding fumes (MIG welding of aluminium and MIG soldering of zinc coated steel) in healthy humans. In a threefold cross-over design study 12 male subjects were exposed to three different exposure scenarios. Exposures were performed under controlled conditions in the Aachener Workplace Simulation Laboratory (AWSL). On three different days the subjects were either exposed to filtered ambient air, to welding fumes from MIG welding of aluminium, or to fumes from MIG soldering of zinc coated materials. Exposure was performed for 6 h and the average fume concentration was 2.5 mg m(-3). Before, directly after, 1 day after, and 7 days after exposure spirometric and impulse oscillometric measurements were performed, exhaled breath condensate (EBC) was collected and blood samples were taken and analyzed for inflammatory markers. During MIG welding of aluminium high ozone concentrations (up to 250 μg m(-3)) were observed, whereas ozone was negligible for MIG soldering. For MIG soldering, concentrations of high-sensitivity CRP (hsCRP) and factor VIII were significantly increased but remained mostly within the normal range. The concentration of neutrophils increased in tendency. For MIG welding of aluminium, the lung function showed significant decreases in Peak Expiratory Flow (PEF) and Mean Expiratory Flow at 75% vital capacity (MEF 75) 7 days after exposure. The concentration of ristocetin cofactor was increased. The observed increase of hsCRP during MIG-soldering can be understood as an indicator for asymptomatic systemic inflammation probably due to zinc (zinc concentration 1.5 mg m(-3)). The change in lung function observed after MIG welding of aluminium may be attributed to ozone inhalation, although the late response (7 days after exposure) is surprising. PMID:23790592

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

    SciTech Connect

    Murakami, Tomoyuki; Okuno, Yoshihiro

    2008-07-28

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

  12. Condensate fraction of asymmetric three-component Fermi gas

    NASA Astrophysics Data System (ADS)

    Du, Jia-Jia; Liang, Jun-Jun; Liang, Jiu-Qing

    2014-02-01

    In this paper, we investigate the condensate fraction (CF) of fermionic pairs in the BCSBEC crossover for three-component Fermi gas with both asymmetric interactions and unequal chemical potentials in two-dimensional free space. By using the functional-path-integral method, we have analytically derived the number densities and bound-state energy, from which the off-diagonal long-range order is analyzed in terms of the asymptotic behavior of the two-body density matrix. The explicit formula of CF is obtained as a function of the bound-state energy and population imbalance. It is demonstrated that the CF spectrum with respect to the bound-state energy can be used to characterize the quantum phase transition between the two kinds of Sarma phases as well as the transition from three-component to two-component superfluid. Moreover we obtain the same analytic formula of CF in the BCS superfluid phase as that of homogeneous Fermi gas with equal chemical potentials.

  13. Ultra-trace level analysis of morpholine, cyclohexylamine, and diethylaminoethanol in steam condensate by gas chromatography with multi-mode inlet, and flame ionization detection.

    PubMed

    Luong, J; Shellie, R A; Cortes, H; Gras, R; Hayward, T

    2012-03-16

    Steam condensate water treatment is a vital and integral part of the overall cooling water treatment process. Steam condensate often contains varying levels of carbon dioxide and oxygen which acts as an oxidizer. Carbon dioxide forms corrosive carbonic acid when dissolved in condensed steam. To neutralize the harmful effect of the carbonic acid, volatile amine compounds such as morpholine, cyclohexylamine, and diethylaminoethanol are often employed as part of a strategy to control corrosion in the water treatment process. Due to the high stability of these compounds in a water matrix, the indirect addition of such chemicals into the process via steam condensate often results in their presence throughout the process and even into the final product. It is therefore important to understand the impact of these chemicals and their fate within a chemical plant. The ability to analyze such compounds by gas chromatography has historically been difficult due to the lack of chromatographic system inertness at the trace level concentrations especially in an aqueous matrix. Here a highly sensitive, practical, and reliable gas chromatographic approach is described for the determination of morpholine, cyclohexylamine, and diethylaminoethanol in steam condensate at the part-per-billion (ppb) levels. The approach does not require any sample enrichment or derivatization. The technique employs a multi-mode inlet operating in pulsed splitless mode with programmed inlet temperature for sample introduction, an inert base-deactivated capillary column for solute separation and flame ionization detection. Chromatographic performance was further enhanced by the incorporation of 2-propanol as a co-solvent. Detection limits for morpholine, cyclohexylamine, diethylaminoethanol were established to be 100 ppb (v/v), with relative standard deviations (RSD) of less than 6% at the 95% confidence level (n=20) and a percent recovery of 96% or higher for the solutes of interest over a range of 0.1-100 ppm (v/v). A complete analysis can be conducted in less than 10 min. PMID:22325017

  14. Dissociation of the effects of alcohol and amphetamine on inert gas narcosis using reaction time and P300 latency.

    PubMed

    Fowler, B; Adams, J

    1993-06-01

    Alcohol exacerbates and amphetamine ameliorates the slowing of reaction time (RT) produced by inert gas narcosis. The event-related brain potential P300 was used to determine whether these drug effects involve stimulus- or response-related processes, since P300 largely reflects the time to evaluate a stimulus while RT reflects this time plus the time to select and execute a response. Subjects breathed nitrous oxide (N2O) alone and in combination with ethyl alcohol or dextroamphetamine while responding to visually presented names that differed in probability (the oddball paradigm). N2O slowed P300, but this measure was comparatively insensitive to the exacerbation and amelioration that were indexed by RT. Relative to N2O alone, an RT-P300 difference was found for amphetamine + N2O but not for alcohol + N2O. We conclude that exacerbation involves both stimulus- and response-related processes but amelioration involves only the latter. This pattern of results can be explained by a model in which the drugs modulate slowing via the two energetical dimensions of arousal and activation, which influence stimulus- and response-related processes, respectively. PMID:8338494

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

    SciTech Connect

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

    1993-11-01

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

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

    SciTech Connect

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

    2010-07-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2006-12-01

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

  18. Magnetic properties of iron-oxide passivated iron nanoparticles synthesized by a gas condensation technique

    NASA Astrophysics Data System (ADS)

    Baker, Colin C.

    Gas phase synthesis processes involve the generation of metal atoms through various means, and the homogeneous nucleation and subsequent condensation and coagulation of nanoparticles. Inert gas condensation (IGC) is a desirable process for the synthesis of metal nanoparticles because it is a relatively simple process capable of producing large quantities of nanoparticles, and since it utilizes vacuum deposition, it offers high purity particles and does not require hazardous chemicals. In this research, the results of the IGC synthesis of iron nanoparticles are presented. The iron nanoparticles are passivated in-situ by slowly introducing oxygen into the chamber to form ferrimagnetic Fe3O4 gamma-Fe2O3 shell/alpha-Fe ferromagnetic core nanoparticles. The magnetic properties of these particles are investigated as a function of passivation layer thickness and particle concentration. The oxide-passivated particles exhibit an exchange bias when cooled below a blocking temperature, which depends on the thickness of the oxide layer present. It was found that the exchange bias increased with oxide thickness. Similarly the blocking temperature also increased with oxide layer thickness. The blocking temperature in all cases, however, was found to be much lower than the Neel temperature for Fe-oxides. The nanoparticles also exhibit a spin glass transition below a characteristic freezing temperature, as evident by a sharp increase in the magnetic moment of the samples. Fe nanoparticle-polymer composite films were also obtained by spin casting mixtures of nanoparticles and polymethylmethacrylate (PMMA). The magnetic properties of these composites were compared to those of particles compressed into pellets. It was observed that when the particles were dispersed into the nanocomposite, the coercivity was increased, suggesting a heightened anisotropy barrier. Similarly, the magnetic relaxation results indicated that the particles dispersed in the PMMA exhibited significantly reduced relaxations through the entire temperature range, as compared to the non-dispersed compressed pellets. It is hoped that this research will result in a greater understanding of the interaction effects between magnetic species. The Fe-oxide/Fe shell/core interactions, may give researchers a better understanding of short-range exchange interactions, while Fe/PMMA composites may elucidate the nature and scope of longer-range dipolar interactions.

  19. An investigation of condensation heat transfer in a closed tube containing a soluble noncondensable gas

    NASA Technical Reports Server (NTRS)

    Saaski, E. W.; Hanson, R. J.

    1976-01-01

    A more exact one-dimensional condensation heat transfer model for insoluble gases was developed and compared with experimental data. Modifications to this model to accommodate soluble gas behavior were also accomplished, and the effects on gas front behavior demonstrated. Analytical models for condensation heat transfer are documented, and an optical method used for measuring gas concentration profiles is outlined. Experimental data is then presented and interpreted.

  20. 46 CFR 153.923 - Inerting systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Inerting systems. 153.923 Section 153.923 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK... Requirements § 153.923 Inerting systems. The master shall ensure that the inert gas systems for any cargo...

  1. 46 CFR 153.923 - Inerting systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Inerting systems. 153.923 Section 153.923 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK... Requirements § 153.923 Inerting systems. The master shall ensure that the inert gas systems for any cargo...

  2. 46 CFR 153.923 - Inerting systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Inerting systems. 153.923 Section 153.923 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK... Requirements § 153.923 Inerting systems. The master shall ensure that the inert gas systems for any cargo...

  3. 46 CFR 153.923 - Inerting systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Inerting systems. 153.923 Section 153.923 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK... Requirements § 153.923 Inerting systems. The master shall ensure that the inert gas systems for any cargo...

  4. Design and evaluation of gas-condensate wells using the systems analysis approach

    SciTech Connect

    Sutton, D.S.

    1987-01-01

    The use of Systems Analysis for designing and evaluating wells flowing hydrocarbon mixtures seems to create no computational problems when considering the inflow components, i.e. reservoir and perforations. However, when a gas-condensate system is considered, the outflow component calculating the total pressure losses in the tubing creates a computational problem. This computational problem involves the estimation of the phase properties of the gas-condensate fluid. Thus, the fluid system undergoes phase changes as it moves up the tubing. Use of a single-phase or two-phase flow model does not overcome this. Although the single-phase flow model adjusts the dry gas specific gravity by adding the condensate fluid into the gas stream. This model is adequate for wells producing small amounts of condensate; consequently, two-phase model is needed to adequately model types of high flow. However, since the phase properties in the two-phase flow model are computed assuming the liquid phase behaves as black oil and condensate fluids and black oil possess distinct differences, a method is needed for predicting pressure losses when condensate fluids flow through pipes, where PVT properties are evaluated using a condensation model. It was decided that a compositional model was the best approach to predict pressure losses for condensate fluids flowing in vertical pipes. Actual case histories were used to test the model by matching these measured flowing pressure traverses.

  5. Non-Condensable Gas Absorption by Capillary Waves

    NASA Astrophysics Data System (ADS)

    Andre, Matthieu A.; Bardet, Philippe M.

    2013-03-01

    Oceans and atmosphere are constantly exchanging heat and mass; this has a direct consequence on the climate. While these exchanges are inherently multi-scales, in non-breaking waves the smallest scales strongly govern the transfer rates at the ocean-atmosphere interface. The present experimental study aims at characterizing and quantifying the exchanges of non-condensable gas at a sub-millimeter scale, in the presence of capillary waves. In oceans, capillaries are generated by high winds and are also present on the forward face of short gravity waves. Capillary waves are thus present over a large fraction of the ocean surface, but their effect on interphase phenomena is little known. In the experiment, 2D capillary waves are generated by the relaxation of a shear layer at the surface of a laminar water slab jet. Wave profile is measured with Planar Laser Induced Fluorescence (PLIF) and 2D velocity field of the water below the surface is resolved with Particle Image Velocimetry (PIV). Special optical arrangements coupled with high speed imaging allow 0.1 mm- and 0.1 ms- resolution. These data reveal the interaction of vorticity and free surface in the formation and evolution of capillaries. The effect of the capillaries on the transfer of oxygen from the ambient air to anoxic water is measured with another PLIF system. In this diagnostic, dissolved oxygen concentration field is indirectly measured using fluorescence quenching of Pyrenebutyric Acid (PBA). The three measurements performed simultaneously -surface profile, velocity field, and oxygen concentration- give deep physical insights into oxygen transfer mechanisms under capillary waves.

  6. Condensate fraction of a two-dimensional attractive Fermi gas

    SciTech Connect

    Salasnich, Luca

    2007-07-15

    We investigate the Bose-Einstein condensation of fermionic pairs in a two-dimensional uniform two-component Fermi superfluid obtaining an explicit formula for the condensate density as a function of the chemical potential and the energy gap. By using the mean-field extended Bardeen-Cooper-Schrieffer theory, we analyze, as a function of the bound-state energy, the off-diagonal long-range order in the crossover from the Bardeen-Cooper-Schrieffer state of weakly bound Cooper pairs to the Bose-Einstein condensate of strongly-bound molecular dimers.

  7. Determination of energy consumption for gas purification by the steam-condensation method

    SciTech Connect

    Khaidarov, G.G.; Isakov, V.P.; Sokolov, V.N.

    1983-02-01

    Energy consumption for gas purification by the steam-condensation method is discussed. Experiments were conducted in an experimental assembly to confirm mathematical equations and to estimate the influences of the steam-condensation effect in gas purification. Comparison of the experimental and calculated values shows that the relationships given can be used for determination of changes of the heating capacity of steam entering and leaving the apparatus.

  8. Use of nuclear explosions to create gas condensate storage in the USSR. LLL Treaty Verification Program

    SciTech Connect

    Borg, I.Y.

    1982-08-23

    The Soviet Union has described industrial use of nuclear explosions to produce underground hydrocarbon storage. To examples are in the giant Orenburg gas condensate field. There is good reason to believe that three additional cavities were created in bedded salt in the yet to be fully developed giant Astrakhan gas condensate field in the region of the lower Volga. Although contrary to usual western practice, the cavities are believed to be used to store H/sub 2/S-rich, unstable gas condensate prior to processing in the main gas plants located tens of kilometers from the producing fields. Detonations at Orenburg and Astrakhan preceded plant construction. The use of nuclear explosions at several sites to create underground storage of highly corrosive liquid hydrocarbons suggests that the Soviets consider this time and cost effective. The possible benefits from such a plan include degasification and stabilization of the condensate before final processing, providing storage of condensate during periods of abnormally high natural gas production or during periods when condensate but not gas processing facilities are undergoing maintenance. Judging from information provided by Soviet specialists, the individual cavities have a maximum capacity on the order of 50,000 m/sup 3/.

  9. Technology of the recovery of helium from Bratsk condensed gas deposit

    SciTech Connect

    Blinov, V.V.

    1995-09-01

    The close location of gas consumers to Bratsk condensed gas deposit and its high helium content have made it possible to organize the economical processing of gas and with small volumes of output (of the order of 440 million m{sup 3}/yr) to obtain each year more than 1 million m{sup 3} of helium, 421 million m{sup 3} of commercial gas, up to 3 thousand tons of liquefied gases, 16.4 thousand tons of gasoline fraction, 35 tons thousand of diesel fuel, and 2.5 thousand tons of boiler fuel. The formation gas contains (in vol. %): helium (0.27), hydrogen (0.12), carbon dioxide (0.24), methane (over 86), propane and butane (1.7), condensate (2.4), and also ethane and nitrogen. The materials from the industrial treatment of gas and condensate and their processing stages are combined in a single complex. The processing of gas and condensate extracted at the industrial separation plant is discussed. In the technology developed for the separation of helium, the energy of the gas itself is principally used, and preliminary absorption (or adsorption) purification of the gas to remove traces of carbon dioxide, a propane cooling unit, or additional compressors for transporting gas to the consumer are not required. Only in the latter stages of helium concentration and its purification is a circulatory compressor used to obtain liquid nitrogen.

  10. Evidence of bias in air-water Henry's law constants for semivolatile organic compounds measured by inert gas stripping.

    PubMed

    Shunthirasingham, Chubashini; Lei, Ying Duan; Wania, Frank

    2007-06-01

    Accurate knowledge of the air-water Henry's law constant (H) is crucial for understanding an organic compound's environmental behavior. The inert gas stripping (IGS) method, widely used to measure H of semivolatile organic compounds (SOCs), may yield erroneously high values for compounds with a high water surface adsorption coefficient, K(IA), because chemical adsorbed to the bubble surface may be transferred to the head space upon bursting at the top of the stripping column. Experiments with alkanols of variable chain length identified a K(IA) threshold of approximately 10(-3) m, above which IGS is susceptible to this artifact. Most SOCs are predicted to have K(IA) values well above that threshold. IGS-determined H-values for chemicals belonging to various groups of SOCs were evaluated by comparison with H-values either calculated from reliable vapor pressure and solubility data or derived from data compilations that achieve thermodynamic consistency through optimized adjustment of measured physical-chemical property data. The investigated deviations were found to be generally consistent with what would be expected from a surface adsorption artifact. Namely, the apparent bias in IGS-determined H-values, if it occurs, (1) is positive, (2) increases with increasing size of an SOC, and (3) increases with decreasing temperature. It generally is also of a magnitude predicted using estimated K(IA) values. However, different studies display different K(IA) threshold values, beyond which the artifact becomes notable, and some studies appear to succeed in avoiding the artifact altogether. Whereas the use of aerosol traps cannot explain the absence of a surface adsorption artifact, it may be related to higher flow rates used by some investigators. For large compounds or those with more than one functional group, the predicted deviation is too large when compared to observations, suggesting that the estimated K(IA) values for those compounds are too high. A full quantitative understanding of the artifact requires more accurate predictions of the adsorption of SOCs to the water surface. PMID:17612153

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

    SciTech Connect

    Elmore, M.R.

    1996-02-01

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

  12. Spinor condensate of {sup 87}Rb as a dipolar gas

    SciTech Connect

    Swislocki, Tomasz; Gajda, Mariusz; RzaPzewski, Kazimierz

    2010-03-15

    We consider a spinor condensate of {sup 87}Rb atoms in the F=1 hyperfine state confined in an optical dipole trap. Putting initially all atoms in the m{sub F}=0 component, we find that the system evolves toward a state of thermal equilibrium with kinetic energy equally distributed among all magnetic components. We show that this process is dominated by the dipolar interaction of magnetic spins rather than spin-mixing contact potential. Our results show that because of a dynamical separation of magnetic components, the spin-mixing dynamics in the {sup 87}Rb condensate is governed by the dipolar interaction which plays no role in a single-component rubidium system in a magnetic trap.

  13. 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.

  14. Interaction of a moving foam with gas condensate in pipeline cleaning

    SciTech Connect

    Tikhomirov, V.K.; Goncharov, V.N.

    1987-09-20

    The authors mathematically analyze the hydraulic and flow behavior of foams and gas condensates during cleaning procedures for the removal of the condensates from pipelines. The model takes into account such properties as shear stress and friction forces as well as the dimensions of the pipeline and the specific surfactant properties of several sulfur-based organic foams. The cleaning rate of the pipeline can be calculated from the model.

  15. 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).

  16. Gas and condensate composition in the deep Tuscaloosa trend, southern Louisiana - influence of oil and wet gas cracking

    SciTech Connect

    Claypool, G.E.; Rooney, M.A.; Vuletich, A.K. )

    1996-01-01

    Natural gas and condensate samples from 34 wells in six fields producing from deep Tuscaloosa sandstones show regular changes in chemical and isotopic composition with increasing depth of burial. A gas-condensate system at 5.2 km (17,000 ft) changes to dry gas at 6.1 km (20,500 ft). Carbon isotopic compositions of ethane and propane become heavier ([delta] [sup 13]C[sub 2] increases from -31 to -23 permil); ([delta][sup 13]C[sub 3] increases from -29 to -21 permil), while methane becomes lighter ([delta][sup 13]C[sub 1] decreases from -38 to -42 permil). Depletion of condensate liquids relative to gas over this same depth interval (condensate/gas ratios decrease from 120 to 1 bbl/mmcf) is accompanied by systematic molecular and isotopic changes in the residual liquids. Higher molecular-weight (>C[sub 20]) hydrocarbons are progressively depleted, and isoprenoids are lost relative to adjacent normal alkanes. The liquids shift to heavier [delta][sup 13]C values (from -27 to -23 permil). These changes are believed to be caused by thermal cracking and progressive conversion of oil and wet gas hydrocarbons to dry gas in Tuscaloosa reservoirs at temperatures of 165 to 195[degrees]C.

  17. Gas and condensate composition in the deep Tuscaloosa trend, southern Louisiana - influence of oil and wet gas cracking

    SciTech Connect

    Claypool, G.E.; Rooney, M.A.; Vuletich, A.K.

    1996-12-31

    Natural gas and condensate samples from 34 wells in six fields producing from deep Tuscaloosa sandstones show regular changes in chemical and isotopic composition with increasing depth of burial. A gas-condensate system at 5.2 km (17,000 ft) changes to dry gas at 6.1 km (20,500 ft). Carbon isotopic compositions of ethane and propane become heavier ({delta} {sup 13}C{sub 2} increases from -31 to -23 permil); ({delta}{sup 13}C{sub 3} increases from -29 to -21 permil), while methane becomes lighter ({delta}{sup 13}C{sub 1} decreases from -38 to -42 permil). Depletion of condensate liquids relative to gas over this same depth interval (condensate/gas ratios decrease from 120 to 1 bbl/mmcf) is accompanied by systematic molecular and isotopic changes in the residual liquids. Higher molecular-weight (>C{sub 20}) hydrocarbons are progressively depleted, and isoprenoids are lost relative to adjacent normal alkanes. The liquids shift to heavier {delta}{sup 13}C values (from -27 to -23 permil). These changes are believed to be caused by thermal cracking and progressive conversion of oil and wet gas hydrocarbons to dry gas in Tuscaloosa reservoirs at temperatures of 165 to 195{degrees}C.

  18. Effect of vapor condensation on forced convection heat transfer of moistened gas

    NASA Astrophysics Data System (ADS)

    Liang, Yongbin; Che, Defu; Kang, Yanbin

    2007-05-01

    The forced convection heat transfer with water vapor condensation is studied both theoretically and experimentally when wet flue gas passes downwards through a bank of horizontal tubes. Extraordinarily, discussions are concentrated on the effect of water vapor condensation on forced convection heat transfer. In the experiments, the air steam mixture is used to simulate the flue gas of a natural gas fired boiler, and the vapor mass fraction ranges from 3.2 to 12.8%. By theoretical analysis, a new dimensionless number defined as augmentation factor is derived to account for the effect of condensation of relatively small amount of water vapor on convection heat transfer, and a consequent correlation is proposed based on the experimental data to describe the combined convection condensation heat transfer. Good agreement can be found between the values of the Nusselt number obtained from the experiments and calculated by the correlation. The maximum deviation is within ±6%. The experimental results also shows that the convection condensation heat transfer coefficient increases with Reynolds number and bulk vapor mass fraction, and is 1˜3.5 times that of the forced convection without condensation.

  19. Economics of Condensing Gas Furnaces and Water Heaters Potential in Residential Single Family Homes

    SciTech Connect

    Lekov, Alex; Franco, Victor; Meyers, Steve

    2010-05-14

    Residential space and water heating accounts for over 90percent of total residential primary gas consumption in the United States. Condensing space and water heating equipment are 10-30percent more energy-efficient than conventional space and water heating. Currently, condensing gas furnaces represent 40 percent of shipments and are common in the Northern U.S. market. Meanwhile, manufacturers are planning to develop condensing gas storage water heaters to qualify for Energy Star? certification. Consumers, installers, and builders who make decisions about installing space and water heating equipment generally do not perform an analysis to assess the economic impacts of different combinations and efficiencies of space and water heating equipment. Thus, equipment is often installed without taking into consideration the potential life-cycle economic and energy savings of installing space and water heating equipment combinations. Drawing on previous and current analysis conducted for the United States Department of Energy rulemaking on amended standards for furnaces and water heaters, this paper evaluates the extent to which condensing equipment can provide life-cycle cost-effectiveness in a representative sample of single family American homes. The economic analyses indicate that significant energy savings and consumer benefits may result from large-scale introduction of condensing water heaters combined with condensing furnaces in U.S. residential single-family housing, particularly in the Northern region. The analyses also shows that important benefits may be overlooked when policy analysts evaluate the impact of space and water heating equipment separately.

  20. Recovery of Water from Boiler Flue Gas Using Condensing Heat Exchangers

    SciTech Connect

    Levy, Edward; Bilirgen, Harun; DuPont, John

    2011-03-31

    Most of the water used in a thermoelectric power plant is used for cooling, and DOE has been focusing on possible techniques to reduce the amount of fresh water needed for cooling. DOE has also been placing emphasis on recovery of usable water from sources not generally considered, such as mine water, water produced from oil and gas extraction, and water contained in boiler flue gas. This report deals with development of condensing heat exchanger technology for recovering moisture from flue gas from coal-fired power plants. The report describes: • An expanded data base on water and acid condensation characteristics of condensing heat exchangers in coal-fired units. This data base was generated by performing slip stream tests at a power plant with high sulfur bituminous coal and a wet FGD scrubber and at a power plant firing highmoisture, low rank coals. • Data on typical concentrations of HCl, HNO{sub 3} and H{sub 2}SO{sub 4} in low temperature condensed flue gas moisture, and mercury capture efficiencies as functions of process conditions in power plant field tests. • Theoretical predictions for sulfuric acid concentrations on tube surfaces at temperatures above the water vapor dewpoint temperature and below the sulfuric acid dew point temperature. • Data on corrosion rates of candidate heat exchanger tube materials for the different regions of the heat exchanger system as functions of acid concentration and temperature. • Data on effectiveness of acid traps in reducing sulfuric acid concentrations in a heat exchanger tube bundle. • Condensed flue gas water treatment needs and costs. • Condensing heat exchanger designs and installed capital costs for full-scale applications, both for installation immediately downstream of an ESP or baghouse and for installation downstream of a wet SO{sub 2} scrubber. • Results of cost-benefit studies of condensing heat exchangers.

  1. Recovery of Water from Boiler Flue Gas Using Condensing Heat Exchangers

    SciTech Connect

    Edward Levy; Harun Bilirgen; John DuPoint

    2011-03-31

    Most of the water used in a thermoelectric power plant is used for cooling, and DOE has been focusing on possible techniques to reduce the amount of fresh water needed for cooling. DOE has also been placing emphasis on recovery of usable water from sources not generally considered, such as mine water, water produced from oil and gas extraction, and water contained in boiler flue gas. This report deals with development of condensing heat exchanger technology for recovering moisture from flue gas from coal-fired power plants. The report describes: (1) An expanded data base on water and acid condensation characteristics of condensing heat exchangers in coal-fired units. This data base was generated by performing slip stream tests at a power plant with high sulfur bituminous coal and a wet FGD scrubber and at a power plant firing high-moisture, low rank coals. (2) Data on typical concentrations of HCl, HNO{sub 3} and H{sub 2}SO{sub 4} in low temperature condensed flue gas moisture, and mercury capture efficiencies as functions of process conditions in power plant field tests. (3) Theoretical predictions for sulfuric acid concentrations on tube surfaces at temperatures above the water vapor dewpoint temperature and below the sulfuric acid dew point temperature. (4) Data on corrosion rates of candidate heat exchanger tube materials for the different regions of the heat exchanger system as functions of acid concentration and temperature. (5) Data on effectiveness of acid traps in reducing sulfuric acid concentrations in a heat exchanger tube bundle. (6) Condensed flue gas water treatment needs and costs. (7) Condensing heat exchanger designs and installed capital costs for full-scale applications, both for installation immediately downstream of an ESP or baghouse and for installation downstream of a wet SO{sub 2} scrubber. (8) Results of cost-benefit studies of condensing heat exchangers.

  2. [Effect of inert gas xenon on the functional state of nucleated cells of peripheral blood during freezing].

    PubMed

    Laptev, D S; Polezhaeva, T V; Zaitseva, O O; Khudyakov, A N; Utemov, S V; Knyazev, M G; Kostyaev, A A

    2015-01-01

    A new method of preservation of nucleated cells in the electric refrigerator with xenon. After slow freezing and storage is even one day at -80 °C persists for more than 60% leukocytes. Cell membranes are resistant to the vital dye. In 85% of granulocytes stored baseline lysosomal-cationic protein, reduced lipid peroxidation and antioxidant activity. Cryopreservation of biological objects in inert gases is a promising direction in the practice of medicine and can be an alternative to the traditional method using liquid nitrogen. PMID:26027341

  3. Silurian shale origin for light oil, condensate, and gas in Algeria and the Middle East

    SciTech Connect

    Zumberge, J.E. ); Macko, S. ) Engel, M. )

    1996-01-01

    Two of the largest gas fields in the world, Hasi R'Mel, Algeria and North Dome, Qatar, also contain substantial condensate and light oil reserves. Gas to source rock geochemical correlation is difficult due to the paucity of molecular parameters in the former although stable isotope composition is invaluable. However, by correlating source rocks with light oils and condensates associated with gas production using traditional geochemical parameters such as biomarkers and isotopes, a better understanding of the origin of the gas is achieved. Much of the crude oil in the Ghadames/Illizi Basins of Algeria has long been thought to have been generated from Silurian shales. New light oil discoveries in Saudi Arabia have also been shown to originate in basal euxinic Silurian shales. Key sterane and terpane biomarkers as well as the stable carbon isotopic compositions of the C15+ saturate and aromatic hydrocarbon fractions allow for the typing of Silurian-sourced, thermally mature light oils in Algeria and the Middle East. Even though biomarkers are often absent due to advanced thermal maturity, condensates can be correlated to the light oils using (1) carbon isotopes of the residual heavy hydrocarbon fractions, (2) light hydrocarbon distributions (e.g., C7 composition), and (3) compound specific carbon isotopic composition of the light hydrocarbons. The carbon isotopes of the C2-C4 gas components ran then be compared to the associated condensate and light oil isotopic composition.

  4. Silurian shale origin for light oil, condensate, and gas in Algeria and the Middle East

    SciTech Connect

    Zumberge, J.E.; Macko, S. Engel, M.

    1996-12-31

    Two of the largest gas fields in the world, Hasi R`Mel, Algeria and North Dome, Qatar, also contain substantial condensate and light oil reserves. Gas to source rock geochemical correlation is difficult due to the paucity of molecular parameters in the former although stable isotope composition is invaluable. However, by correlating source rocks with light oils and condensates associated with gas production using traditional geochemical parameters such as biomarkers and isotopes, a better understanding of the origin of the gas is achieved. Much of the crude oil in the Ghadames/Illizi Basins of Algeria has long been thought to have been generated from Silurian shales. New light oil discoveries in Saudi Arabia have also been shown to originate in basal euxinic Silurian shales. Key sterane and terpane biomarkers as well as the stable carbon isotopic compositions of the C15+ saturate and aromatic hydrocarbon fractions allow for the typing of Silurian-sourced, thermally mature light oils in Algeria and the Middle East. Even though biomarkers are often absent due to advanced thermal maturity, condensates can be correlated to the light oils using (1) carbon isotopes of the residual heavy hydrocarbon fractions, (2) light hydrocarbon distributions (e.g., C7 composition), and (3) compound specific carbon isotopic composition of the light hydrocarbons. The carbon isotopes of the C2-C4 gas components ran then be compared to the associated condensate and light oil isotopic composition.

  5. Condensation from supernova gas made of free atoms^1

    NASA Astrophysics Data System (ADS)

    Ebel, D. S.; Grossman, L.

    2001-02-01

    Silicon carbide grains and graphite spherules containing TiC inclusions are found in the Murchison carbonaceous chondrite. The high 44Ca (from 44Ti) and 28Si contents of these grains are strong evidence that all three minerals originated in the deep zones of Type II supernova ejecta. We present equilibrium calculations for SN shells, and show that TiC, but not graphite or SiC, is a stable condensate in the innermost shells where [Ti + Si] >> [C + O], even though C/O < 1 in these shells. Because of the great stability of gaseous CO, however, neither carbides nor graphite can survive at chemical equilibrium in the massive O-rich shells which separate the heavy element-rich inner sources of 44Ti and 28Si from outer C-rich zones where these minerals would be stable. Clayton et al. (1999) found that, under circumstances where all gaseous molecules and particularly CO are completely dissociated by Compton electrons, specific choices of kinetic parameters enable the prediction of graphite formation, even in an O-rich supernova shell. Following up on this hypothesis, we calculated high-temperature equilibrium condensation sequences in the absence of polyatomic molecules for gases having canonical solar, and supernova shell compositions. Graphite is indeed predicted to be stable in O-dominated supernova zones in the absence of gaseous molecules. But the complementary phases found in meteorites, TiC and SiC, are not stable under these conditions, while SiO 2, which is not found, is produced in abundance. Without resolving these discrepancies between theory and observation, the problem of reconciling the zone where the mineralogical identities of supernova grains were established with the zone implied by their isotopic compositions remains unsolved.

  6. Effect of Non-Condensable Gas on the Subcooled Water Critical Flow in a Safety Valve

    SciTech Connect

    Se Won Kim; Sang Kyoon Lee; Hee Cheon No

    2002-07-01

    The effect of non-condensable gas on the subcooled water critical flow in a safety valve is investigated experimentally at various sub-cooling with 3 different disk lifts. To evaluate its effect on the critical pressure ratio and critical flow rate, three parameters are considered: the ratios of outlet pressure to inlet pressure, the subcooling to inlet temperature, and the gas volumetric flow to water volumetric flow are 0.15-0.23, 0.07-0.12, and 0-0.8, respectively. It turns out that the critical pressure ratio is mainly dependent on the subcooling, and its dependency on the gas fraction and the pressure drop is relatively small. When the ratio of nitrogen gas volumetric flow to water volumetric flow becomes lower than 20%, the subcooled water critical flow rate is decreased about 10 % compare to the water flow rate of without non-condensable gas. However, it maintains a constant value after the ratio of gas volumetric flow to water volumetric flow becomes higher than 20%. The subcooled water critical flow correlation, which considers subcooling, disc lift, back-pressure, and non-condensable gas, shows good agreement with the total present experimental data with the root mean square error 8.17%. (authors)

  7. Emergence of coherence via transverse condensation in a uniform quasi-two-dimensional Bose gas

    NASA Astrophysics Data System (ADS)

    Chomaz, Lauriane; Corman, Laura; Bienaimé, Tom; Desbuquois, Rémi; Weitenberg, Christof; Nascimbène, Sylvain; Beugnon, Jérôme; Dalibard, Jean

    2015-01-01

    Phase transitions are ubiquitous in our three-dimensional world. By contrast, most conventional transitions do not occur in infinite uniform low-dimensional systems because of the increased role of thermal fluctuations. The crossover between these situations constitutes an important issue, dramatically illustrated by Bose-Einstein condensation: a gas strongly confined along one direction of space may condense along this direction without exhibiting true long-range order in the perpendicular plane. Here we explore transverse condensation for an atomic gas confined in a novel trapping geometry, with a flat in-plane bottom, and we relate it to the onset of an extended (yet of finite-range) in-plane coherence. By quench crossing the transition, we observe topological defects with a mean number satisfying the universal scaling law predicted by Kibble-Zurek mechanism. The approach described can be extended to investigate the topological phase transitions that take place in planar quantum fluids.

  8. Emergence of coherence via transverse condensation in a uniform quasi-two-dimensional Bose gas.

    PubMed

    Chomaz, Lauriane; Corman, Laura; Bienaimé, Tom; Desbuquois, Rémi; Weitenberg, Christof; Nascimbène, Sylvain; Beugnon, Jérôme; Dalibard, Jean

    2015-01-01

    Phase transitions are ubiquitous in our three-dimensional world. By contrast, most conventional transitions do not occur in infinite uniform low-dimensional systems because of the increased role of thermal fluctuations. The crossover between these situations constitutes an important issue, dramatically illustrated by Bose-Einstein condensation: a gas strongly confined along one direction of space may condense along this direction without exhibiting true long-range order in the perpendicular plane. Here we explore transverse condensation for an atomic gas confined in a novel trapping geometry, with a flat in-plane bottom, and we relate it to the onset of an extended (yet of finite-range) in-plane coherence. By quench crossing the transition, we observe topological defects with a mean number satisfying the universal scaling law predicted by Kibble-Zurek mechanism. The approach described can be extended to investigate the topological phase transitions that take place in planar quantum fluids. PMID:25635999

  9. Analysis of Vapour Liquid Equilibria in Unconventional Rich Liquid Gas Condensate Reservoirs

    NASA Astrophysics Data System (ADS)

    Kuczyński, Szymon

    2014-12-01

    At the beginning of 21st century, natural gas from conventional and unconventional reservoirs has become important fossil energy resource and its role as energy fuel has increased. The exploration of unconventional gas reservoirs has been discussed recently in many conferences and journals. The paper presents considerations which will be used to build the thermodynamic model that will describe the phenomenon of vapour - liquid equilibrium (VLE) in the retrograde condensation in rocks of ultra-low permeability and in the nanopores. The research will be limited to "tight gas" reservoirs (TGR) and "shale gas" reservoirs (SGR). Constructed models will take into account the phenomenon of capillary condensation and adsorption. These studies will be the base for modifications of existing compositional simulators

  10. Bose-Einstein condensation in a dilute rubidium-87 gas

    NASA Astrophysics Data System (ADS)

    Hong, Seokchan

    We present an apparatus for the study of Bose-Einstein condensation (BEC), and discuss an experiment performed with it. The apparatus is constructed for the creation of dilute gaseous rubidium BEC using various cooling and trapping techniques such as magneto-optical trap, moving molasses, polarization gradient cooling and evaporation cooling forced by microwave transition. A BEC of 1x105 87Rb atoms can be created in 45 seconds with this apparatus. Then we discuss an experiment of rotating BEC with small number of atoms in a newly configured optical lattice. In this optical lattice, there are many identical and independent 2D disk-shaped potential wells, each of which can be deformed elliptic and rotated around the symmetric axis of it. Compare to the other rotating BEC experiment, the ratio of the number of atoms to the number of angular momentum per atom can be much smaller and approach to order of one. This may lead us to the regime of the fractional quantum Hall effect.

  11. The Dynamics of Partial Cavities and Effect of Non-Condensable Gas

    NASA Astrophysics Data System (ADS)

    Makiharju, Simo A.; Ganesh, Harish; Ceccio, Steven L.

    2015-11-01

    Partial cavitation is encountered in a variety of common applications, from fuel injectors to lifting surfaces, and in general it has detrimental effects on the system wear and performance. Partial cavities undergoing auto-oscillation can cause large pressure oscillations, unsteady hydrodynamic loading, and significant noise. In the present study, experiments were conducted focusing on the dynamics of shedding cavities forming in a canonical geometry (downstream of a wedge apex). The inlet cavitation number was fixed at 2.0 and the Reynolds number based on the hydraulic diameter was 6x105. The effects of dissolved gas content and of non-condensable gas injection into the cavity were carefully studied utilizing dynamic pressure transducers and x-ray densitometry. Gas was injected either immediately downstream of the wedge's apex or further downstream into mid-cavity. The gas injected near the wedge apex was found to end up in the separated shear layer, and relatively miniscule amounts of gas were enough to significantly reduce the vapor production rate and dampen the cavity's auto-oscillations. In addition, the results suggest that non-condensable gas injection can cause the shedding mechanism to switch from one dominated by condensation shock to one dominated by re-entrant liquid jet. Work supported by the Office of Naval Research Grant N00014-14-1-0292, program manager Dr. Ki-Han Kim.

  12. Confined Phase Envelope of Gas-Condensate Systems in Shale Rocks

    NASA Astrophysics Data System (ADS)

    Nagy, Stanislaw; Siemek, Jakub

    2014-12-01

    Natural gas from shales (NGS) and from tight rocks are one of the most important fossil energy resource in this and next decade. Significant increase in gas consumption, in all world regions, will be marked in the energy sector. The exploration of unconventional natural gas & oil reservoirs has been discussed recently in many conferences. This paper describes the complex phenomena related to the impact of adsorption and capillary condensation of gas-condensate systems in nanopores. New two phase saturation model and new algorithm for search capillary condensation area is discussed. The algorithm is based on the Modified Tangent Plane Criterion for Capillary Condensation (MTPCCC) is presented. The examples of shift of phase envelopes are presented for selected composition of gas-condensate systems. Gaz ziemny z łupków (NGS) oraz z ze złóż niskoprzepuszczalnych (typu `tight') staje się jednym z najważniejszych zasobów paliw kopalnych, w tym i następnym dziesięcioleciu. Znaczący wzrost zużycia gazu we wszystkich regionach świata zaznacza się głównie w sektorze energetycznym. Rozpoznawanie niekonwencjonalnych złóż gazu ziemnego i ropy naftowej w ostatnim czasie jest omawiane w wielu konferencjach. Niniejszy artykuł opisuje złożone zjawiska związane z wpływem adsorpcji i kapilarnej kondensacji w nanoporach w złożach gazowo-kondensatowych. Pokazano nowy dwufazowy model równowagowy dwufazowy i nowy algorytm wyznaczania krzywej nasycenia w obszarze kondensacji kapilarnej. Algorytm bazuje na kryterium zmodyfikowanym płaszczyzny stycznej dla kapilarnej kondensacji (MTPCCC). Przykłady zmiany krzywych nasycenia są przedstawiane w wybranym składzie systemów gazowo- kondensatowych

  13. Numerical analysis of filmwise condensation in a plate fin-and-tube heat exchanger in presence of non-condensable gas

    NASA Astrophysics Data System (ADS)

    Benelmir, Riad; Mokraoui, Salim; Souayed, Ali

    2009-10-01

    In the present paper, a numerical model of a fin-and-tube heat exchanger is proposed. The simulation of water vapor condensation in presence of non-condensable gas (air) between two vertical plane plates and in a plate fin-and-tube heat exchanger in a stationary mode is performed using Fluent software. The differential equations that describe the heat and mass transfer were integrated by the finite volume method, in two and three dimensions.

  14. Momentum Distribution and Condensate Fraction of a Fermion Gas in the BCS-BEC Crossover

    SciTech Connect

    Astrakharchik, G.E.; Boronat, J.; Casulleras, J.; Giorgini, S.

    2005-12-02

    By using the diffusion Monte Carlo method we calculate the one- and two-body density matrix of an interacting Fermi gas at T=0 in the BCS to Bose-Einstein condensate (BEC) crossover. Results for the momentum distribution of the atoms, as obtained from the Fourier transform of the one-body density matrix, are reported as a function of the interaction strength. Off-diagonal long-range order in the system is investigated through the asymptotic behavior of the two-body density matrix. The condensate fraction of pairs is calculated in the unitary limit and on both sides of the BCS-BEC crossover.

  15. Exciton gas compression and metallic condensation in a single semiconductor quantum wire.

    PubMed

    Alén, B; Fuster, D; Muñoz-Matutano, G; Martínez-Pastor, J; González, Y; Canet-Ferrer, J; González, L

    2008-08-01

    We study the metal-insulator transition in individual self-assembled quantum wires and report optical evidence of metallic liquid condensation at low temperatures. First, we observe that the temperature and power dependence of the single nanowire photoluminescence follow the evolution expected for an electron-hole liquid in one dimension. Second, we find novel spectral features that suggest that in this situation the expanding liquid condensate compresses the exciton gas in real space. Finally, we estimate the critical density and critical temperature of the phase transition diagram at n{c} approximately 1 x 10;{5} cm;{-1} and T{c} approximately 35 K, respectively. PMID:18764504

  16. Evolution of non-condensable gas in ammonia heat pipes

    NASA Technical Reports Server (NTRS)

    Richter, Robert

    1990-01-01

    Accumulation of noncondensible gas (NCG) has been observed in ammonia heat pipes. NCG has been found to be detrimental to the performance of heat pipes and can result in complete operational failure. A kinetic and thermodynamic analysis has been performed that evaluates the dissociation of ammonia under various conditions and predicts the amount of NCG present in heat pipes. The analysis indicates that the observed NCG in ammonia heat pipes can be attributed to the dissociation of ammonia into its constituents, hydrogen and nitrogen. It shows time and temperature to be the important parameters, in conjunction with the catalytic characteristic of the container material.

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

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

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

  18. 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

  19. Measuring Diffusivity in Supercooled Liquid Nanoscale Films using Inert Gas Permeation: II. Diffusion of AR, KR, Xe, and CH4 through Methanol

    SciTech Connect

    Matthiesen, Jesper; Smith, R. Scott; Kay, Bruce D.

    2010-11-07

    We present an experimental technique to measure the diffusivity of supercooled liquids at temperatures near their Tg. The approach uses the permeation of inert gases through supercooled liquid overlayers as a measure of the diffusivity of the supercooled liquid itself. The desorption spectra of the probe gas is used to extract the low temperature supercooled liquid diffusivities. In the preceding companion paper, we derived equations using ideal model simulations from which the diffusivity could be extracted using the desorption peak times for isothermal or peak temperatures for TPD experiments. Here, we discuss the experimental conditions for which these equations are valid and demonstrate their utility using amorphous methanol with Ar, Kr, Xe, and CH4 as probe gases. The approach offers a new method by which the diffusivities of supercooled liquids can be measured in the experimentally challenging temperature regime near the glass transition temperature.

  20. Chemical stimulation of gas condensate reservoirs: An experimental and simulation study

    NASA Astrophysics Data System (ADS)

    Kumar, Viren

    Well productivity in gas condensate reservoirs is reduced by condensate banking when the bottom hole flowing pressure drops below the dewpoint pressure. Several methods have been proposed to restore gas production rates after a decline due to condensate blocking. Gas injection, hydraulic fracturing, horizontal wells and methanol injection have been tried with limited success. These methods of well stimulation either offer only temporary productivity restoration or are applicable only in some situations. Wettability alteration of the rock in the near well bore region is an economic and efficient method for the enhancement of gas-well deliverability. Altering the wettability of porous media from strongly water-wet or oil-wet to intermediate-wet decreases the residual liquid saturations and results in an increase in the relative permeability to gas. Such treatments also increase the mobility and recovery of condensate from the reservoir. This study validates the above hypothesis and provides a simple and cost-efficient solution to the condensate blocking problem. Screening studies were carried out to identify the chemicals based on structure, solubility and reactivity at reservoir temperature and pressure. Experiments were performed to evaluate these chemicals to improve gas and condensate relative permeabilities. The improvement in relative permeability after chemical treatment was quantified by performing high pressure and high temperature coreflood experiments in Berea sandstone, Texas Cream limestone and reservoir cores using synthetic gas mixtures at reservoir conditions. Experiments were done at high flow rates and for long time periods to evaluate the durability of the treatment. Single well simulation studies were conducted to demonstrate the performance of the chemical treatment in the field. The experimental relative permeability data was modeled using a trapping number dependent relative permeability model and incorporated in the simulations. Effect of connate water saturation, drawdown pressure, skin, treatment radius and the timing of the treatment during the life of the reservoir were investigated using a compositional simulator. Spectroscopic studies using a scanning electron microscope, neutron magnetic resonance and time of flight-secondary ion mass spectroscopy were used to determine the structural and reactive chemistry of the chemicals used and to evaluate the extent of treatment on the rock surface. The study allows us to postulate and partly verify a detailed mechanism of interaction between the rock surface and the chemical.

  1. Effect of Alternate Supply of Shielding Gases of Tungsten Inert Gas Welding on Mechanical Properties of Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Shinde, Neelam Vilas; Telsang, Martand Tamanacharya

    2016-03-01

    In the present study, an attempt is made to study the effect of alternate supply of the shielding gas in comparison with the conventional method of TIG welding with pure argon gas. The two sets of combination are used as 10-10 and 40-20 s for alternate supply of the Argon and Helium shielding gas respectively. The effect of alternate supply of shielding gas is studied on the mechanical properties like bend test, tensile test and impact test. The full factorial experimental design is applied for three set of combinations. The ANOVA is used to find significant parameters for the process and regression analysis used to develop the mathematical model. The result shows that the alternate supply of the shielding gas for 10-10 s provides better result for the bend, tensile and impact test as compared with the conventional argon gas and the alternate supply of 40-20 s argon and helium gas respectively. Welding speed can be increased for alternate supply of the shielding gas that can reduce the total welding cost.

  2. Terahertz Active Photonic Crystals for Condensed Gas Sensing

    PubMed Central

    Benz, Alexander; Deutsch, Christoph; Brandstetter, Martin; Andrews, Aaron M.; Klang, Pavel; Detz, Hermann; Schrenk, Werner; Strasser, Gottfried; Unterrainer, Karl

    2011-01-01

    The terahertz (THz) spectral region, covering frequencies from 1 to 10 THz, is highly interesting for chemical sensing. The energy of rotational and vibrational transitions of molecules lies within this frequency range. Therefore, chemical fingerprints can be derived, allowing for a simple detection scheme. Here, we present an optical sensor based on active photonic crystals (PhCs), i.e., the pillars are fabricated directly from an active THz quantum-cascade laser medium. The individual pillars are pumped electrically leading to laser emission at cryogenic temperatures. There is no need to couple light into the resonant structure because the PhC itself is used as the light source. An injected gas changes the resonance condition of the PhC and thereby the laser emission frequency. We achieve an experimental frequency shift of 10−3 times the center lasing frequency. The minimum detectable refractive index change is 1.6 × 10−5 RIU. PMID:22163939

  3. Gas chromatographic analysis of petroleum associated condensate oil with simultaneous determination of some characteristic physical parameters.

    PubMed

    Moustafa, N E

    2008-01-01

    A method is developed for the analysis of associated condensate by capillary gas chromatography (GC) with simultaneous determination of its major physical characteristic parameters. The method aims at the qualitative and quantitative determination of C(2)-C(36) alkanes, methylcyclopentane, cyclohexane, methylcyclohexane, benzene, toluene, ethylbenzene, xylenes, and 1,2,4-trimethylbenzene. This composition is according to the petroleum companies demand. The method is used for the simultaneous determination of the condensate average molecular weight, density, carbon-to-hydrogen ratio, and boiling range. The data obtained by the method has a good agreement with those obtained by other methods. The literature methods cited later used a simulated distillation method to obtain the hydrocarbon distribution spectrum of the given condensate sample. The obtained results revealed that the GC capillary method used is most rapid and accurate for achieving the demanded analytical report. PMID:18492346

  4. Pairing, ferromagnetism, and condensation of a normal spin-1 Bose gas

    SciTech Connect

    Natu, Stefan S.; Mueller, Erich J.

    2011-11-15

    We find the conditions under which the normal state of a spin-1 Bose gas is unstable toward condensation, ferromagnetism, liquid crystalline-like nematicity, and Bardeen-Cooper-Schrieffer-like pairing. When the spin-dependent interactions are much weaker than the density-density interaction there is direct transition from a featureless normal state to a fully ordered Bose-Einstein condensate with either ferromagnetic or nematic order. When the spin-independent and spin-dependent interactions are of comparable magnitude, we find several different symmetry breaking transitions at intermediate temperatures above the Bose-condensation transition temperature. We make predictions for the T{sub c} for these transitions, and assess the role of magnetic field and finite system size.

  5. Experimental determination of Henry's law constant of perfluorooctanoic acid (PFOA) at 298 K by means of an inert-gas stripping method with a helical plate

    NASA Astrophysics Data System (ADS)

    Kutsuna, Shuzo; Hori, Hisao

    The Henry's law constant ( KH) of perfluorooctanoic acid (PFOA, C 7F 15C(O)OH) was determined at 298 K in aqueous sulfuric acid solutions and in aqueous sodium chloride and sulfuric acid mixtures by an inert-gas stripping method in which a helical plate was used to increase the residence time of the gas bubbles in the solutions. The partial pressures of C 7F 15C(O)OH in the purge gas ( PPFOA) were determined by means of Fourier-transform infrared spectroscopy. Time-courses of PPFOA and concentrations of PFOA in the test solutions ( CPFOA) differed from those typically obtained by an inert-gas stripping, indicating both the presence of C 7F 15C(O)OH aggregates, even at low concentrations of C 7F 15C(O)OH in aqueous sulfuric acid solutions, and the adsorption of gaseous C 7F 15C(O)OH on the walls of the experimental apparatus. We derived overall gas-to-water partition coefficients ( KH') by simulating the time-courses of PPFOA and CPFOA simultaneously to optimize parameters of the model relating to the partitioning, the aggregation, and the adsorption. The KH' value for 0.31 mol dm -3 sulfuric acid solutions at 298 K was determined at 3.8 ± 0.1 mol dm -3 atm -1. From the relationship between KH' and the ionic strength of aqueous sulfuric acid solutions, the KH values of C 7F 15C(O)OH at 298 K were determined at 9.9 ± 1.5 mol dm -3 atm -1 for p Ka = 2.8 and 5.0 ± 0.2 mol dm -3 atm -1 for p Ka = 1.3. The p Ka value of 1.3 seems to be most probable among the reported three values for C 7F 15C(O)OH, taking into account dependence of KH' on sulfuric acid concentrations for aqueous sodium chloride and sulfuric acid mixtures. Despite the low p Ka value, the relatively small KH of C 7F 15C(O)OH obtained at 298 K suggests a substantial partitioning of C 7F 15C(O)OH in air in the environment.

  6. Numerical Simulation of Stationary AC Tungsten Inert Gas Welding of Aluminum Plate in Consideration of Oxide Layer Cleaning

    NASA Astrophysics Data System (ADS)

    Tashiro, Shinichi; Tanaka, Manabu

    An unified numerical simulation model of AC TIG welding of the aluminum plate considering energy balance among the electrode, the arc and the base metal and employing an analytical model for calculating cleaning rate of the oxide layer has been developed for investigating heat transport properties and weld pool formation process in AC TIG welding of aluminum plate. As a result of this simulation, it was shown that although the heat flux from the arc onto the base metal increases in EN (Electrode Negative) phase due to the electron condensation, that in EP (Electrode Positive) phase conversely decreases because mainly of cooling caused by the electron emission. Furthermore, the validity of the simulation model was confirmed by comparing to experimental results such as the arc voltage, the area of cleaning zone and the shape of weld pool.

  7. Signature of the existence of a coherently condensed state in a dilute gas above the Bose-Einstein-condensate transition temperature

    NASA Astrophysics Data System (ADS)

    Yang, Yinbiao; Wang, Wen-ge

    2015-01-01

    We study quantum coherence properties of a dilute gas at temperatures above, but not much above, the transition temperature of Bose-Einstein condensation. In such a gas, a small proportion of the atoms may possess coherence lengths longer than the mean neighboring-atomic distance, implying the existence of quantum coherence greater than that expected for thermal atoms. Conjecturing that a part of this proportion of the atoms may lie in a coherently condensed state, some unexplained experimental results [D. E. Miller et al., Phys. Rev. A 71, 043615 (2005), 10.1103/PhysRevA.71.043615] can be explained.

  8. Inert electrode connection

    DOEpatents

    Weyand, John D.; Woods, Robert W.; DeYoung, David H.; Ray, Siba P.

    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.

  9. Study of materials to resist corrosion in condensing gas fired furnaces

    NASA Astrophysics Data System (ADS)

    Lahtvee, T.; Khoo, S. W.; Schaus, O. O.

    1981-02-01

    Based on a thorough review of background information on the performance of materials in condensing gas fired furnace heat exchangers and in similar corrosive environments candidate materials were selected and tested on one of two identical test rigs built to provide the varying corrosive conditions encountered in an actual gas fired condensing system heat exchanger. The 32 different materials tested in a one month screening test included: mild, low alloy, galvanized, solder coated and CaCO3 dipped galvanized steel, porcelain, epoxy, teflon and nylon coated and alonized mild steel; austenitic, ferritic, low interstitial Ti stabilized ferritic, and high alloy stainless steels; aluminum alloy anodized and porcelain coated aluminum; copper and cupronickel alloys, solder coated copper; and titanium.

  10. Critical behavior of the ideal-gas Bose-Einstein condensation in the Apollonian network.

    PubMed

    de Oliveira, I N; dos Santos, T B; de Moura, F A B F; Lyra, M L; Serva, M

    2013-08-01

    We show that the ideal Boson gas displays a finite-temperature Bose-Einstein condensation transition in the complex Apollonian network exhibiting scale-free, small-world, and hierarchical properties. The single-particle tight-binding Hamiltonian with properly rescaled hopping amplitudes has a fractal-like energy spectrum. The energy spectrum is analytically demonstrated to be generated by a nonlinear mapping transformation. A finite-size scaling analysis over several orders of magnitudes of network sizes is shown to provide precise estimates for the exponents characterizing the condensed fraction, correlation size, and specific heat. The critical exponents, as well as the power-law behavior of the density of states at the bottom of the band, are similar to those of the ideal Boson gas in lattices with spectral dimension d(s)=2ln(3)/ln(9/5)~/=3.74. PMID:24032807

  11. Numerical simulation of the gas-condensate pipeline during shutdown and restart processes by AUSM+ scheme

    NASA Astrophysics Data System (ADS)

    Gong, Jing; Yin, Tienan; Wang, Zhi

    2013-07-01

    The transient multiphase simulation has been a research focus in the related fields. In this paper a two-fluid model of the transient two phase flow in the pipeline is set up, including the continuity, momentum and energy equations. Due to its many advantages the AUSM+ scheme is introduced into the solution scheme of the two-fluid model. In order to be incorporated with the AUSM+ scheme, the conservative general formula for the two-fluid model is given. The solution scheme with AUSM+ is also described in detail. A typical long distance offshore gas-condensate pipeline is chosen as an example. The steady state of this pipeline was simulated as initial condition of the transient process. The shutdown and restart processes were simulated on the basis of steady state. From the results the transient process of the gas-condensate pipeline was investigated. The variable distribution, the wave propagation, and the liquid accumulation are all reflected by the results.

  12. Effect of Non-Condensable Gas Injection on Cavitation Dynamics of Partial Cavities

    NASA Astrophysics Data System (ADS)

    Mäkiharju, Simo A.; Ganesh, Harish; Ceccio, Steven L.

    2015-12-01

    Partial cavities can undergo auto-oscillation causing large pressure pulsations, unsteady loading of machinery and generate significant noise. In the current experiments fully shedding cavities forming in the separated flow region downstream of a wedge were investigated. The Reynolds number based on hydraulic diameter was of the order of one million. The cavity dynamics were studied with and without injection of non-condensable gas into the cavity. Gas was injected directly into the cavitation region downstream of the wedge's apex, or into the recirculating region at mid cavity so that for the same amount of injected gas less ended up in the shear layer. It was found that relatively miniscule amounts of gas introduced into the shear layer at the cavity interface can reduce vapour production and dampen the auto oscillations, and the same amount of gas injected into the mid cavity would not have the same effect. The authors also examined whether the injected gas can switch the shedding mechanism from one dominated by condensation shock to one dominantly by reentrant jet.

  13. 33 CFR 154.824 - Inerting, enriching, and diluting systems.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Systems § 154.824 Inerting, enriching, and diluting systems. (a) A vapor control system which uses... vapor control system which uses an inerting, enriching, or diluting system must be equipped with a gas... the injection point; (c) A vapor control system that uses an inerting or enriching system may not...

  14. Structure of a supersonic gas jet under conditions of developed condensation

    NASA Astrophysics Data System (ADS)

    Zarvin, A. E.; Yaskin, A. S.; Kalyada, V. V.; Ezdin, B. S.

    2015-11-01

    The method of flow visualization by electron-beam-induced radiation emission has been used to study the shape and structure of supersonic gas jets emitted into rarefied submerged space via sonic and supersonic nozzles from a forechamber at high pressure (stagnation pressure P 0). It is established that the longitudinal size of a traditional primary supersonic jet increases with the stagnation pressure at fixed ratio P 0/ P h, where P h is the surrounding background gas pressure. This character of jet expansion via both sonic and supersonic nozzles is related to variation of the condensate fraction and average cluster size in the jet. Under the conditions of formation of large-size clusters in the supersonic jet of argon, a nontraditional gas jet shape with a long "wake" has been observed. No such secondary structure has been observed during the expansion of noncondensing helium and weakly condensing nitrogen. It is suggested that the formation of wake under conditions of developed condensation and significant rarefaction is related to the formation of a secondary clustered jet.

  15. Quantification of Conventional and Nonconventional Charge-Assisted Hydrogen Bonds in the Condensed and Gas Phases.

    PubMed

    Katsyuba, Sergey A; Vener, Mikhail V; Zvereva, Elena E; Fei, Zhaofu; Scopelliti, Rosario; Brandenburg, Jan Gerit; Siankevich, Sviatlana; Dyson, Paul J

    2015-11-01

    Charge-assisted hydrogen bonds (CAHBs) play critical roles in many systems from biology through to materials. In none of these areas has the role and function of CAHBs been explored satisfactorily because of the lack of data on the energy of CAHBs in the condensed phases. We have, for the first time, quantified three types of CAHBs in both the condensed and gas phases for 1-(2'-hydroxylethyl)-3-methylimidazolium acetate ([C2OHmim][OAc]). The energy of conventional OH[OAc](-) CAHBs is ?10 kcalmol(-1), whereas nonconventional C(sp2)H[OAc](-) and C(sp3)H[OAc](-) CAHBs are weaker by ?5-7 kcalmol(-1). In the gas phase, the strength of the nonconventional CAHBs is doubled, whereas the conventional CAHBs are strengthened by <20%. The influence of cooperativity effects on the ability of the [OAc](-) anion to deprotonate the imidazolium cation is evaluated. The ability to quantify CAHBs in the condensed phase on the basis of easier accessible gas-phase estimates is highlighted. PMID:26496074

  16. Acoustic Instabilities Driven by Slip Between a Condensed Phase and the Gas Phase in Combustion Systems

    NASA Technical Reports Server (NTRS)

    DiCicco, M.; Buckmaster, J.

    1994-01-01

    In the context of gas turbine combustion chambers, this study describes how slip affects the response time of fuel sprays to pressure fluctuations in a gaseous flow field. Slip between the condensed and gas phases is shown to cause fuel vapor mass fraction fluctuations upstream of the reaction zone. A resulting oscillating heat release can drive the pressure fluctuations, depending on the phase difference between them. This generates an acoustic instability. With relevance to previous experimental results, differences are explored in the evaporation characteristics among three different fuel sprays (JP-4, JP-5, and D-2) in relation to their effect on the magnitude of the fuel vapor mass fraction perturbations.

  17. Laws of the DC arc in an inert gas during melting in furnaces with a tungsten electrode

    NASA Astrophysics Data System (ADS)

    Belyanchikov, L. N.

    2012-06-01

    The I-V and voltage-baric characteristics of the dc arc glowing in argon between a tungsten cathode and a molten anode made of titanium, chromium, or manganese are studied at various gas pressures, arc currents, and arc lengths. The arc is probed to establish the relation between the voltage drop across the arc and its regions on the anode material and the melting conditions.

  18. Condensate fraction of a resonant Fermi gas with spin-orbit coupling in three and two dimensions

    SciTech Connect

    Dell'Anna, L.; Mazzarella, G.; Salasnich, L.

    2011-09-15

    We study the effects of laser-induced Rashba-like spin-orbit coupling along the Bardeen-Cooper-Schrieffer-Bose-Einstein condensate (BCS-BEC) crossover of a Feshbach resonance for a two-spin-component Fermi gas. We calculate the condensate fraction in three and two dimensions and find that this quantity characterizes the crossover better than other quantities, like the chemical potential or the pairing gap. By considering both the singlet and the triplet pairings, we calculate the condensate fraction and show that a large-enough spin-orbit interaction enhances the singlet condensate fraction in the BCS side while suppressing it on the BEC side.

  19. Experimental investigation of steam condensation in a horizontal tube in the presence of noncondensable gas

    SciTech Connect

    Tiejun Wu; Karen Vierow; Hideaki Tokuma

    2004-07-01

    A horizontal heat exchanger design is being developed for the Passive Containment Cooling System (PCCS) of future light water reactors. The horizontal heat exchanger would be part of the PCCS that is called upon following a hypothesized severe accident or Loss of Coolant Accident (LOCA). In the current research, a countercurrent double pipe heat exchanger is designed to mechanistically study the heat transfer and fluid flow phenomena in the heat exchanger tube (31.75 mm O.D., 3.0 m long). The degradation effect of noncondensable gas was also studied. A test matrix of 31 test conditions was covered. The steam flow rate ranged from 11.5{approx}46 g/s. The inlet air volumetric fraction was 1%{approx}20%. The test section inlet total pressure range was from 0.1 MPa to 0.4 MPa. 14 temperature measurement cross sections were arranged along the heat transfer section with 7 thermocouples on each cross section to acquire the local heat transfer data and address the asymmetrical heat transfer characteristics around the periphery of the condenser tube. Instead of calculating the local heat flux from the coolant temperature profile along the test section, the temperature gradient through the condenser tube wall was measured locally, which avoids the inaccuracy caused by the complex coolant mixing. Based on the experiment data, the condensation heat transfer coefficients on the top and bottom of the tube were calculated separately. This provides unique and essential fundamental data to understand and model the condensation process. (authors)

  20. Method and apparatus for removing non-condensible gas from a working fluid in a binary power system

    DOEpatents

    Mohr, Charles M.; Mines, Gregory L.; Bloomfield, K. Kit

    2002-01-01

    Apparatus for removing non-condensible gas from a working fluid utilized in a thermodynamic system comprises a membrane having an upstream side operatively connected to the thermodynamic system so that the upstream side of the membrane receives a portion of the working fluid. The first membrane separates the non-condensible gas from the working fluid. A pump operatively associated with the membrane causes the portion of the working fluid to contact the membrane and to be returned to the thermodynamic system.

  1. Microbial reduction of sulfate injected to gas condensate plumes in cold groundwater

    NASA Astrophysics Data System (ADS)

    Van Stempvoort, Dale R.; Armstrong, James; Mayer, Bernhard

    2007-07-01

    Despite a rapid expansion over the past decade in the reliance on intrinsic bioremediation to remediate petroleum hydrocarbon plumes in groundwater, significant research gaps remain. Although it has been demonstrated that bacterial sulfate reduction can be a key electron accepting process in many petroleum plumes, little is known about the rate of this reduction process in plumes derived from crude oil and gas condensates at cold-climate sites (mean temperature < 10 °C), and in complex hydrogeological settings such as silt/clay aquitards. In this field study, sulfate was injected into groundwater contaminated by gas condensate plumes at two petroleum sites in Alberta, Canada to enhance in-situ bioremediation. In both cases the groundwater near the water table had low temperature (6-9 °C). Monitoring data had provided strong evidence that bacterial sulfate reduction was a key terminal electron accepting process (TEAP) in the natural attenuation of dissolved hydrocarbons at these sites. At each site, water with approximately 2000 mg/L sulfate and a bromide tracer was injected into a low-sulfate zone within a condensate-contaminant plume. Monitoring data collected over several months yielded conservative estimates for sulfate reduction rates based on zero-order kinetics (4-6 mg/L per day) or first-order kinetics (0.003 and 0.01 day - 1 ). These results favor the applicability of in-situ bioremediation techniques in this region, under natural conditions or with enhancement via sulfate injection.

  2. Transport Membrane Condenser for Water and Energy Recovery from Power Plant Flue Gas

    SciTech Connect

    Dexin Wang

    2012-03-31

    The new waste heat and water recovery technology based on a nanoporous ceramic membrane vapor separation mechanism has been developed for power plant flue gas application. The recovered water vapor and its latent heat from the flue gas can increase the power plant boiler efficiency and reduce water consumption. This report describes the development of the Transport Membrane Condenser (TMC) technology in details for power plant flue gas application. The two-stage TMC design can achieve maximum heat and water recovery based on practical power plant flue gas and cooling water stream conditions. And the report includes: Two-stage TMC water and heat recovery system design based on potential host power plant coal fired flue gas conditions; Membrane performance optimization process based on the flue gas conditions, heat sink conditions, and water and heat transport rate requirement; Pilot-Scale Unit design, fabrication and performance validation test results. Laboratory test results showed the TMC system can exact significant amount of vapor and heat from the flue gases. The recovered water has been tested and proved of good quality, and the impact of SO{sub 2} in the flue gas on the membrane has been evaluated. The TMC pilot-scale system has been field tested with a slip stream of flue gas in a power plant to prove its long term real world operation performance. A TMC scale-up design approach has been investigated and an economic analysis of applying the technology has been performed.

  3. Pairing, ferromagnetism, and condensation of a normal spin-1 Bose gas

    NASA Astrophysics Data System (ADS)

    Natu, Stefan; Mueller, Erich

    2011-05-01

    We theoretically study the stability of a normal, spin disordered, homogenous spin-1 Bose gas against ferromagnetism, pairing, and condensation through a Random Phase Approximation which includes exchange (RPA-X). Repulsive spin-independent interactions stabilize the normal state against both ferromagnetism and pairing, and for typical interaction strengths leads to a direct transition from an unordered normal state to a fully ordered single particle condensate. Atoms with much larger spin-dependent interaction may experience a transition to a ferromagnetic normal state or a paired superfluid, but, within the RPA-X, there is no instability towards a normal state with spontaneous nematic order. We analyze the role of the quadratic Zeeman effect and finite system size.

  4. Raman-induced temporal condensed matter physics in gas-filled photonic crystal fibers.

    PubMed

    Saleh, Mohammed F; Armaroli, Andrea; Tran, Truong X; Marini, Andrea; Belli, Federico; Abdolvand, Amir; Biancalana, Fabio

    2015-05-01

    Raman effect in gases can generate an extremely long-living wave of coherence that can lead to the establishment of an almost perfect temporal periodic variation of the medium refractive index. We show theoretically and numerically that the equations, regulate the pulse propagation in hollow-core photonic crystal fibers filled by Raman-active gas, are exactly identical to a classical problem in quantum condensed matter physics - but with the role of space and time reversed - namely an electron in a periodic potential subject to a constant electric field. We are therefore able to infer the existence of Wannier-Stark ladders, Bloch oscillations, and Zener tunneling, phenomena that are normally associated with condensed matter physics, using purely optical means. PMID:25969278

  5. 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 α-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.

  6. Influence of the growing parameters on the size distribution of PbTe nanoparticles produced by laser ablation under inert gas atmosphere

    NASA Astrophysics Data System (ADS)

    Almeida, D. B.; Rodriguez, E.; Agouram, S.; Moreira, R. S.; Cesar, C. L.; Jimenez, E.; Barbosa, L. C.

    2012-03-01

    We report the fabrication of PbTe quantum dots grown under inert gas (Ar and He) atmosphere by pulsed laser deposition using the second harmonic of a Q-Switched Quantel Nd:YAG laser. For characterization, samples were prepared onto a 40Å carbon film deposited on a copper grid. The influence of background pressure, and number of laser pulses on the size distribution of the PbTe nanoparticles was investigated by transmission electron microscopy using a 200 kV TECNAI G2 F20 electron microscope with 0.27 nm point resolution. The size distribution was obtained by manually outlining the particles from several dozens of low- and high-resolution TEM images. Once digitized and saved in a proper format, the image was processed using the J-image software. Characterizations reveal an increase of the nanoparticle size both with the amount of material deposited (number of laser pulses) and the background pressure. Furthermore, measurements reveal a narrower nanoparticle size distribution by increasing the number of laser pulses or by decreasing the background pressure. HRTEM studies of the influence of different ambient gases on the structural properties of the PbTe nanoparticles are being conducted.

  7. Effect of heat input on the microstructure and mechanical properties of tungsten inert gas arc butt-welded AZ61 magnesium alloy plates

    SciTech Connect

    Min Dong; Shen Jun; Lai Shiqiang; Chen Jie

    2009-12-15

    In this paper, the effects of heat input on the microstructures and mechanical properties of tungsten inert gas arc butt-welded AZ61 magnesium alloy plates were investigated by microstructural observations, microhardness tests and tensile tests. The results show that with an increase of the heat input, the grains both in the fusion zone and the heat-affected zone coarsen and the width of the heat-affected zone increased. Moreover, an increase of the heat input resulted in a decrease of the continuous {beta}-Mg{sub 17}Al{sub 12} phase and an increase of the granular {beta}-Mg{sub 17}Al{sub 12} phase in both the fusion zone and the heat-affected zone. The ultimate tensile strength of the welded joint increased with an increase of the heat input, while, too high a heat input resulted in a decrease of the ultimate tensile strength of the welded joint. In addition, the average microhardness of the heat-affected zone and fusion zone decreased sharply with an increase of the heat input and then decreased slowly at a relatively high heat input.

  8. Controlled inert gas environment for enhanced chlorine and fluorine detection in the visible and near-infrared by laser-induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Asimellis, George; Hamilton, Stephen; Giannoudakos, Aggelos; Kompitsas, Michael

    2005-08-01

    Efficient quantitative detection for halogens is necessary in a wide range of applications, ranging from pharmaceutical products to air polluting hazardous gases or organic compounds used as chemical weapons. Detection of the non-metallic elements such as fluorine (F) and chlorine (Cl) presents particular difficulty, because strong emission lines originating from their resonance states lie in the VUV spectral range (110-190 nm). In the present work we detect F and Cl in the upper visible and in the near IR (650-850 nm) under controlled inert gas ambient atmosphere. Investigation of the controlled atmosphere effects suggests that there exists an optimum pressure range that optimizes signal strength and quality. Ablation and ionization were achieved with a UV laser at 355 nm, and a gated GaAs photocathode-based detector was used for detection with quantum efficiency in the range of 20% in the wavelengths of interest. Our results indicate that our approach provides quantitative detection with linearity over at least two orders of magnitude that is achieved without the need for Internal Standardization Method, and improved limits of detection. In particular, fluorine has been detected for concentration values down to 0.03 wt.% Definite spectral assignment revealing all major emission lines centered around 837 nm for F and 687 nm for Cl has been obtained for the first time in Laser-induced breakdown spectroscopy application.

  9. 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?j?ek, J.; Kavka, T.; Bertolissi, G.; Ctibor, P.; Vilmov, M.; Mulek, R.; Nevrl, 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.

  10. 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 θ (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.

  11. Cal Canal Field, California: case history of a tight and abnormally pressured gas condensate reservoir

    SciTech Connect

    Engineer, R.

    1985-03-01

    The Cal Canal Field, situated in the San Joaquin Valley near Bakersfield, California, produces a rich (280 bbl/MMSCF) gas condensate from an average depth of 11,500 feet. The upper Miocene Stevens Sand, the producing formation in the field, is a very tight, abnormally pressured gas condensate reservoir. The average reservoir parameters are 12 percent porosity, .01 to .1 md permeability and a connate water saturation of 59%. The dew point pressure of 5835 psi is 1508 psi below the initial reservoir pressure. The material balance method, corrected for abnormal pressure, indicates an original wet gas-in-place of 103.3 BSCF. Production performance history suggests that the ultimate recovery from the field will be approximately + or - 10% of the original wet GIP. Such a poor recovery could be attributed to retrograde fallout and increasing water saturation in the vicinity of the wellbores. This paper presents an analysis of the reservoir characteristics and a review of its performance to date. The purpose of the study was to investigate the feasibility of improving hydrocarbon recovery from the field.

  12. Laboratory Evaporation Testing Of Hanford Waste Treatment Plant Low Activity Waste Off-Gas Condensate Simulant

    SciTech Connect

    Adamson, Duane J.; Nash, Charles A.; McCabe, Daniel J.; Crawford, Charles L.; Wilmarth, William R.

    2014-01-27

    The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream, LAW Off-Gas Condensate, from the off-gas system. The baseline plan for disposition of this stream is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility again. Alternate disposition of this stream would eliminate recycling of problematic components, and would enable de-coupled operation of the LAW melter and the Pretreatment Facilities. Eliminating this stream from recycling within WTP would also decrease the LAW vitrification mission duration and quantity of canistered glass waste forms. This LAW Off-Gas Condensate stream contains components that are volatile at melter temperatures and are problematic for the glass waste form. Because this stream recycles within WTP, these components accumulate in the Condensate stream, exacerbating their impact on the number of LAW glass containers that must be produced. Approximately 32% of the sodium in Supplemental LAW comes from glass formers used to make the extra glass to dilute the halides to be within acceptable concentration ranges in the LAW glass. Diverting the stream reduces the halides in the recycled Condensate and is a key outcome of this work. Additionally, under possible scenarios where the LAW vitrification facility commences operation prior to the WTP Pretreatment facility, identifying a disposition path becomes vitally important. This task examines the impact of potential future disposition of this stream in the Hanford tank farms, and investigates auxiliary evaporation to enable another disposition path. Unless an auxiliary evaporator is used, returning the stream to the tank farms would require evaporation in the 242-A evaporator. This stream is expected to be unusual because it will be very high in corrosive species that are volatile in the melter (chloride, fluoride, sulfur), will have high ammonia, and will contain carryover particulates of glass-former chemicals. These species have potential to cause corrosion of tanks and equipment, precipitation of solids, release of ammonia gas vapors, and scale in the tank farm evaporator. Routing this stream to the tank farms does not permanently divert it from recycling into the WTP, only temporarily stores it prior to reprocessing. Testing is normally performed to demonstrate acceptable conditions and limits for these compounds in wastes sent to the tank farms. The primary parameter of this phase of the test program was measuring the formation of solids during evaporation in order to assess the compatibility of the stream with the evaporator and transfer and storage equipment. The origin of this LAW Off-Gas Condensate stream will be the liquids from the Submerged Bed Scrubber (SBS) and the Wet Electrostatic Precipitator (WESP) from the LAW facility melter offgas system. The stream is expected to be a dilute salt solution with near neutral pH, and will likely contain some insoluble solids from melter carryover. The soluble components are expected to be mostly sodium and ammonium salts of nitrate, chloride, and fluoride. This stream has not been generated yet, and, thus, the composition will not be available until the WTP begins operation, but a simulant has been produced based on models, calculations, and comparison with pilot-scale tests. This report discusses results of evaporation testing of the simulant. Two conditions were tested, one with the simulant at near neutral pH, and a second at alkaline pH. The neutral pH test is comparable to the conditions in the Hanford Effluent Treatment Facility (ETF) evaporator, although that evaporator operates at near atmospheric pressure and tests were done under vacuum. For the alkaline test, the target pH was based on the tank farm corrosion control program requirements, and the test protocol and equipment was comparable to that used for routine evaluation of feed compatibility studies for the 242-A evaporator. One of the radionuclides that is volatile in the melter and expected to be in high concentration in this LAW Off-Gas Condensate stream is Technetium-99 (99Tc). Technetium will not be removed from the aqueous waste in the Hanford WTP, and will primarily end up immobilized in the LAW glass by repeated recycle of the off-gas condensate into the LAW melter. Other radionuclides that are also expected to be in appreciable concentrations in the LAW Off-Gas Condensate are 129I, 90Sr, 137Cs, and 241Am. The concentrations of these radionuclides in this stream will be much lower than in the LAW, but they will still be higher than limits for some of the other disposition pathways currently available. At this time, these scoping tests did not evaluate the partitioning of the radionuclides to the evaporator condensate, since ample data are available separately from other experience in the DOE complex. Results from the evaporation testing show that the neutral SBS simulant first forms turbidity at ~7.5X concentration, while the alkaline-adjusted simulant became turbid at ~3X concentration. The major solid in both cases was Kogarkoite, Na3FSO4. Sodium and lithium fluorides were also detected. Minimal solids were formed in the evaporator bottoms until a substantial fraction of liquid was removed, indicating that evaporation could minimize storage volume issues. Achievable concentration factors without significant insoluble solids were 17X at alkaline pH, and 23X at neutral pH. In both runs, significant ammonia carried over and was captured in the condenser with the water condensate. Results also indicate that with low insoluble solids formation in the initial testing at neutral pH, the use of Reverse Osmosis is a potential alternate method for concentrating the solution, although an evaluation is needed to identify equipment that can tolerate insoluble solids. Most of the ammonia remains in the evaporator bottoms during the neutral pH evaporation, but partitions to the condensate during alkaline evaporation. Disposition of both streams needs to consider the management of ammonia vapor and its release. Since this is an initial phase of testing, additional tasks related to evaporation methods are expected to be identified for development. These tasks likely include evaluation and testing of composition variability testing and evaluations, corrosion and erosion testing, slurry storage and immobilization investigations, and evaporator condensate disposition.

  13. A case study of the natural attenuation of gas condensate hydrocarbons in soil and groundwater.

    PubMed

    Barker, G W; Raterman, K T; Fisher, J B; Corgan, J M; Trent, G L; Brown, D R; Kemp, N; Sublette, K L

    1996-01-01

    Condensate liquids have been found to contaminate soil and groundwater at two gas production sites in the Denver Basin operated by Amoco Production Co. These sites have been closely monitored since July 1993 to determine whether intrinsic aerobic or anaerobic bioremediation of hydrocarbons occurs at a sufficient rate and to an adequate end point to support a no-intervention decision. Groundwater monitoring and analysis of soil cores suggest that intrinsic bioremediation is occurring at these sites by multiple pathways, including aerobic oxidation, Fe(III) reduction, and sulfate reduction. PMID:8669918

  14. Renormalization Theory of a Two Dimensional Bose Gas: Quantum Critical Point and Quasi-Condensed State

    NASA Astrophysics Data System (ADS)

    Cenatiempo, S.; Giuliani, A.

    2014-07-01

    We present a renormalization group construction of a weakly interacting Bose gas at zero temperature in the two-dimensional continuum, both in the quantum critical regime and in the presence of a condensate fraction. The construction is performed within a rigorous renormalization group scheme, borrowed from the methods of constructive field theory, which allows us to derive explicit bounds on all the orders of renormalized perturbation theory. Our scheme allows us to construct the theory of the quantum critical point completely, both in the ultraviolet and in the infrared regimes, thus extending previous heuristic approaches to this phase. For the condensate phase, we solve completely the ultraviolet problem and we investigate in detail the infrared region, up to length scales of the order (λ ^3ρ _0)^{-1/2} (here λ is the interaction strength and ρ _0 the condensate density), which is the largest length scale at which the problem is perturbative in nature. We exhibit violations to the formal Ward Identities, due to the momentum cutoff used to regularize the theory, which suggest that previous proposals about the existence of a non-perturbative non-trivial fixed point for the infrared flow should be reconsidered.

  15. Changes in the composition of formation gases in gas-condensate fields formed by vertical migration

    SciTech Connect

    Stepanova, G.S.; Slobodskoy, M.I.; Lukin, A.E.; Levashev, V.N.

    1982-12-01

    A model was developed for calculating the change in gas composition in the pool during its formation by vertical migration. A conical trap with varying cap-rock thickness was considered. Amputations were made for different thermodynamic conditions, different initial states of the gas entering the trap, and different flow rates. The coefficient of compressibility of the gaseous phase was calculated from the Redlich-Quong equation. The results gave the degree of filling of the trap with gas and its composition as functions of time. It was concluded: (1) one of the main factors determining the composition of the formation mixture in a pool formed by vertical migration was diffusion processes, (2) the data on changes in the composition of the formation gas obtained from the theoretical model of hydrocarbon diffusive dispersion through the caprock was not at variance with the actual patterns noted in gas-condensate fields formed by vertical migration and (3) statistical study of fields in the Dnepr-Donets Basin had established a relationship between the composition of the formation gas and the properties of the caprock. 3 references, 4 figures.

  16. Effect of Non-Condensable Gas on Cavity Dynamics and Sheet to Cloud Transition

    NASA Astrophysics Data System (ADS)

    Makiharju, Simo; Ganesh, Harish; Ceccio, Steven

    2014-11-01

    Partial cavitation occurs in numerous industrial and naval applications. Cavities on lifting surfaces, in cryogenic rocket motors or in fuel injectors can damage equipment and in general be detrimental to the system performance, especially as partial cavities can undergo auto-oscillation causing large pressure pulsations, unsteady loading of machinery and generate significant noise. In the current experiments incipient, intermittent cloud shedding and fully shedding cavities forming in the separated flow region downstream of a wedge were investigated. The Reynolds number based on hydraulic diameter was of the order of one million. Gas was injected directly into the cavitation region downstream of the wedge's apex or into the recirculating region such that with the same amount of injected gas less ended up in the shear layer. The cavity dynamics were studied with and without gas injection. The hypothesis to be tested were that i) relatively miniscule amounts of gas introduced into the shear layer at the cavity interface can reduce vapor production and ii) gas introduced into the separated region can dampen the auto oscillations. The authors also examined whether the presence of gas can switch the shedding mechanism from one dominated by condensation shock to one dominantly by re-entrant jet. The work was supported by ONR Grant Number N00014-11-1-0449.

  17. Conservation and greenhouse gas benefits of an electricity producing condensing furnace

    SciTech Connect

    Wicks, F.

    1998-07-01

    A December, 1997 International Conference on Climate Change in Kyoto, Japan defined the need and developed recommendations to decrease emissions of greenhouse gases to 20% below 1990 levels by 2005. Suggested methods include switching from coal to natural gas and more use of nuclear, solar and wind for electricity production. President Clinton followed on January 31, 1998 by announcing a $6.3 billion plan for the US to fight global warming comprised of tax breaks for more energy efficient cars and buildings and more spending on research to further reduce heat trapping emissions. The purpose of this paper is to present a better and more cost effective method. The proposed Electricity Producing Condensing Furnace (EPCF) is a technology that will produce a substantial decrease in CO{sup 2} which is the primary greenhouse gas while providing the additional benefits of decreased fuel consumption and also stimulating the development of a major new manufacturing and service industry. The EPCF is a simple system with large potential benefits that result from combining the fuel saving principle of cogeneration with the fuel saving principle of a condensing furnace. It was conceived and designed by the author to be a cost effective replacement for a gas hot air furnace. It consists of a single cylinder air cooled engine connected to an induction motor/generator and space heat recovery from both the engine and heat exchangers between the circulating space air and the engine exhaust stream. 20% of the input energy in the fuel is converted to grid connected electricity and virtually all of the remaining is recovered as space heat. Recognizing that electricity is a highly refined form of orderly energy that is about four times more valuable than space heat which is a low quality form of disorderly energy, the effective fuel efficiency of this fundamentally simple system is about 160%. This efficiency is relative to a 100% heating system that produces no work or electricity but does convert all of the fuel energy into space heat such as an unvented and unhealthy kerosene or gas heater. The author submits the EPCF should define a new efficiency standard for natural gas fueled heating. If all existing furnaces were converted to the EPCF the benefits in terms of decreased production of CO{sub 2} and decreased fuel consumption would be an order of magnitude larger and the costs would be orders of magnitude lower than any of the other proposed greenhouse gas techniques such as solar, wind, fuel cells and additional nuclear power. This paper will describe the principle, design, operation and acceptance challenges that must be overcome for the Electricity Producing Condensing Furnace to become the new standard for heating system performance.

  18. Use of compositional simulation in the management of Arun gas condensate reservoir

    SciTech Connect

    Sutan-Assin, T.; Rastogi, S.C.; Abdullah, M. ); Hidayat, D. ); Bette, S.; Heineman, R.F. )

    1988-01-01

    This paper describes the simulation of the Arun gas condensate reservoir using a fully compositional simulator, COSMOS (COmpositional System Mobil Oil Simulator). The reservoir is a Miocene carbonate reef complex which occurs at a depth of approximately 10,000 feet, and is up to 1,000 feet thick in some areas. The Arun reservoir is a compositionally dynamic system. The purpose of this simulation study was to predict future reservoir performance under various demand scenarios and optimize gas and NGL recovery. The simulation model utilizes the Peng-Robinson equation of state to account for the compositionally dynamic behavior of the reservoir in predictions of future performance. The equation of state was modified to incorporate special features for Arun such as water vaporization in the reservoir under high temperature conditions.

  19. Coherent Control of Multiphoton Transitions in the Gas and Condensed Phases with Shaped Ultrashort Pulses

    SciTech Connect

    Marcos Dantus

    2008-09-23

    Controlling laser-molecule interactions has become an integral part of developing devices and applications in spectroscopy, microscopy, optical switching, micromachining and photochemistry. Coherent control of multiphoton transitions could bring a significant improvement of these methods. In microscopy, multi-photon transitions are used to activate different contrast agents and suppress background fluorescence; coherent control could generate selective probe excitation. In photochemistry, different dissociative states are accessed through two, three, or more photon transitions; coherent control could be used to select the reaction pathway and therefore the yield-specific products. For micromachining and processing a wide variety of materials, femtosecond lasers are now used routinely. Understanding the interactions between the intense femtosecond pulse and the material could lead to technologically important advances. Pulse shaping could then be used to optimize the desired outcome. The scope of our research program is to develop robust and efficient strategies to control nonlinear laser-matter interactions using ultrashort shaped pulses in gas and condensed phases. Our systematic research has led to significant developments in a number of areas relevant to the AMO Physics group at DOE, among them: generation of ultrashort phase shaped pulses, coherent control and manipulation of quantum mechanical states in gas and condensed phases, behavior of isolated molecules under intense laser fields, behavior of condensed phase matter under intense laser field and implications on micromachining with ultrashort pulses, coherent control of nanoparticles their surface plasmon waves and their nonlinear optical behavior, and observation of coherent Coulomb explosion processes at 10^16 W/cm^2. In all, the research has resulted in 36 publications (five journal covers) and nine invention disclosures, five of which have continued on to patenting

  20. The improvement of the effectiveness of using natural gas in hot-water boilers by means of condensing economizers

    NASA Astrophysics Data System (ADS)

    Vnukov, A. K.; Rozanova, F. A.

    2013-07-01

    The paper describes the results of the study of the mathematical model of a condensing economizer (CE) interacting with the technological parameter of the particular district heating station. This model has been developed by the authors. It is shown that the CE, due to condensation of water vapor and augmentation of convective heat exchange between products of natural gas combustion, makes it possible to save up to 8% of fuel.

  1. Investigation of Bose Condensation in Ideal Bose Gas Trapped under Generic Power Law Potential in d Dimension

    NASA Astrophysics Data System (ADS)

    Mir Mehedi, Faruk; Md. Sazzad, Hossain; Md. Muktadir, Rahman

    2016-02-01

    The changes in characteristics of Bose condensation of ideal Bose gas due to an external generic power law potential U=\\sumi=1dci\\vert xi/ai\\vertni are studied carefully. Detailed calculation of Kim et al. (J. Phys. Condens. Matter 11 (1999) 10269) yielded the hierarchy of condensation transitions with changing fractional dimensionality. In this manuscript, some theorems regarding specific heat at constant volume CV are presented. Careful examination of these theorems reveal the existence of hidden hierarchy of the condensation transition in trapped systems as well.

  2. 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.

  3. 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.

  4. Classification of gasoline by octane number and light gas condensate fractions by origin with using dielectric or gas-chromatographic data and chemometrics tools.

    PubMed

    Rudnev, Vasiliy A; Boichenko, Alexander P; Karnozhytskiy, Pavel V

    2011-05-15

    The approach for classification of gasoline by octane number and light gas condensate fractions by origin with using dielectric permeability data has been proposed and compared with classification of same samples on the basis of gas-chromatographic data. The precision of dielectric permeability measurements was investigated by using ANOVA. The relative standard deviation of dielectric permeability was in the range from 0.3 to 0.5% for the range of dielectric permeability from 1.8 to 4.4. The application of exploratory chemometrics tools (cluster analysis and principal component analysis) allow to explicitly differentiate the gasoline and light gas condensate fractions into groups of samples related to specific octane number or origin. The neural networks allow to perfectly classifying the gasoline and light gas condensate fractions. PMID:21482310

  5. Study of materials to resist corrosion in condensing gas-fired furnaces. Final report Oct 79-Dec 81

    SciTech Connect

    Lahtvee, T.; Schaus, O.O.

    1982-02-01

    Based on a thorough review of background information on the performance of materials in condensing gas-fired heat exchangers and similar corrosive environments, candidate materials were examined on test equipment built to provide the varying corrosive conditions encountered in actual gas-fired condensing system heat exchangers. The 32 different materials tested in a one month screening test included: mild, low alloy, galvanized, solder coated steel, porcelain, epoxy, teflon and nylon coated and alonized mild steel; austenitic, ferritic, low interstitial Ti stabilized ferritic, and high alloy stainless steels; aluminum alloys, anodized and porcelain coated aluminum; copper and cupronickel alloys, solder coated copper; and titanium.

  6. Laboratory optimization tests of technetium decontamination of Hanford Waste Treatment Plant low activity waste melter off-gas condensate simulant

    SciTech Connect

    Taylor-Pashow, Kathryn M.L.; McCabe, Daniel J.

    2015-11-01

    The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream (LAW Off-Gas Condensate) from the off-gas system. The baseline plan for disposition of this stream is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility again. Alternate disposition of this stream would eliminate recycling of problematic components, and would enable simplified operation of the LAW melter and the Pretreatment Facilities. Eliminating this stream from recycling within WTP would also decrease the LAW vitrification mission duration and quantity of glass waste.

  7. Anaerobic biodegradation of natural gas condensate can be stimulated by the addition of gasoline.

    PubMed

    Prince, Roger C; Suflita, Joseph M

    2007-08-01

    Biodegradation of a broad range of linear and branched alkanes, parent and alkyl alicyclic hydrocarbons, and benzene and alkyl-substituted benzenes was observed when sediment and groundwater samples collected from a gas condensate-contaminated aquifer were incubated under methanogenic and especially under sulfate-reducing conditions, even though no exogenous nitrogen or phosphorus was added. This finding expands the range of hydrocarbon molecules known to undergo anaerobic decay and confirms that natural attenuation is an important process at this site. The addition of 1 mul of gasoline to the samples (approximately 10 ppm) had minimal impact on the biodegradation of saturated compounds, but substantially increased the diversity and extent of aromatic compounds undergoing transformation. We attribute this to the promotion or induction of biodegradation pathways in the indigenous microflora following the addition of the gasoline components. The promoting compounds are not precisely known, but may have been present in the initial condensate and reduced in concentration by various mechanisms (dissolution, biodegradation, etc.) such that their concentration in the aquifer fell below necessary levels. A variety of aromatic hydrocarbons would appear to be likely candidates. PMID:17115106

  8. Inert Anode Report

    SciTech Connect

    none,

    1999-07-01

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

  9. Nanocrystalline BaTiO{sub 3} from gas-condensation process

    SciTech Connect

    Li, S.; Eastman, J.A.; Thompson, L.J.; Bjormander, C.; Foster, C.M.

    1996-12-31

    Nanocrystalline BaTiO{sub 3} can be prepared by gas condensation, with an average particle size as small as 18 nm. The stoichiometry of nanocrystalline BaTiO{sub 3} particles can be controlled precisely and reproducibly. Nanocrystalline BaTiO{sub 3} powders, fabricated by a novel e-beam evaporation method, show good sintering behavior which can be sintered to a high density at a temperature as low as 1200 C and exhibit a relatively large dielectric constant than that of coarse-grained ceramics. A thermal analysis was also carried out to assert the lowest limit temperature for forming nanostructured BaTiO{sub 3} from Ba/Ti oxidized clusters at ambient pressure.

  10. Aspects of hyperspherical adiabaticity in an atomic-gas Bose-Einstein condensate

    SciTech Connect

    Kushibe, Daisuke; Mutou, Masaki; Morishita, Toru; Watanabe, Shinichi; Matsuzawa, Michio

    2004-12-01

    Excitation of an atomic-gas Bose-Einstein condensate (BEC) in the zeroth-order ground-state channel is studied with the hyperspherical adiabatic method of Bohn et al. [Bohn et al., Phys. Rev. A 58, 584 (1998)] suitably generalized to accommodate the anisotropic trapping potential. The method exploits the system's size as an adiabatic parameter so that the explicit size dependence is immediately conducive to the virial theorem. The oscillation frequencies associated with the monopole (breathing) and quadrupole modes thus emerge naturally and converge to the well-known Thomas-Fermi limits. Analysis of the single-particle density and the projected excitation wave function shows that the excitation in the single hyperspherical ground-state channel merely represents a progressive increase in occupancy of the first excited single-particle state. The work paves the way for applying the adiabatic picture to other BEC phenomena.

  11. Aspects of hyperspherical adiabaticity in an atomic-gas Bose-Einstein condensate

    NASA Astrophysics Data System (ADS)

    Kushibe, Daisuke; Mutou, Masaki; Morishita, Toru; Watanabe, Shinichi; Matsuzawa, Michio

    2004-12-01

    Excitation of an atomic-gas Bose-Einstein condensate (BEC) in the zeroth-order ground-state channel is studied with the hyperspherical adiabatic method of Bohn [Bohn , Phys. Rev. A 58, 584 (1998)] suitably generalized to accommodate the anisotropic trapping potential. The method exploits the systems size as an adiabatic parameter so that the explicit size dependence is immediately conducive to the virial theorem. The oscillation frequencies associated with the monopole (breathing) and quadrupole modes thus emerge naturally and converge to the well-known Thomas-Fermi limits. Analysis of the single-particle density and the projected excitation wave function shows that the excitation in the single hyperspherical ground-state channel merely represents a progressive increase in occupancy of the first excited single-particle state. The work paves the way for applying the adiabatic picture to other BEC phenomena.

  12. High performance turbocompressor for non-condensable gas removal at geothermal power plants

    SciTech Connect

    Forsha, M.D.

    1998-07-01

    Initial field tests have been completed for a Non-Condensable Gas (NCG) turbocompressor for geothermal power plants. It provides alternate technology to steam-jet ejectors and liquid-ring vacuum pumps that are currently used for NCG removal. It incorporates a number of innovative design features to enhance reliability, reduce steam consumption and reduce O and M costs. During initial field tests, the turbocompressor has been on-line for more than 8,000 hours as a third stage compressor at The Geysers Unit 11 Power Plant. Test data indicates its overall efficiency is about 25% higher than a liquid-ring vacuum pump, and 250% higher than a steam-jet ejector when operating with inlet pressures of 12.2 in-Hg and flow rates over 20,000 lbm/hr.

  13. Fast transit gas- and condensed-phase chemistry of energetic materials

    SciTech Connect

    Skocypec, R.D.; Erickson, K.L.; Renlund, A.M.; Trott, W.M.

    1989-01-01

    An experimental system is being developed to study the fast transient kinetics governing solid-phase decomposition and subsequent interaction with decomposition products. The first phase of this work addresses the decomposition step. The experimental system integrates a thin-film sample configuration with two chemical diagnostic techniques, time-of-flight mass spectrometry and time-resolved infrared spectral photography, and a pulsed-laser heat source. This system is designed to examine both condensed-phase mechanisms and concurrent gas-phase species evolution from samples at temperatures up to 1000{degree}C with microsecond temporal resolution. Tests are underway to demonstrate and assess the use of thin-film samples with the experimental system. Results of these tests, the diagnostic capabilities of the experimental system, and the advantages, preparation and characterization of thin-film samples are presented. 19 refs., 4 figs.

  14. Optimization of gas condensate Field A development on the basis of "reservoir - gathering facilities system" integrated model

    NASA Astrophysics Data System (ADS)

    Demidova, E. A.; Maksyutina, O. V.

    2015-02-01

    It is known that many gas condensate fields are challenged with liquid loading and condensate banking problems. Therefore, gas production is declining with time. In this paper hydraulic fracturing treatment was considered as a method to improve the productivity of wells and consequently to exclude the factors that lead to production decline. This paper presents the analysis of gas condensate Field A development optimization with the purpose of maintaining constant gas production at the 2013 level for 8 years taking into account mentioned factors . To optimize the development of the filed, an integrated model was created. The integrated model of the field implies constructing the uniform model of the field consisting of the coupling models of the reservoir, wells and surface facilities. This model allowed optimizing each of the elements of the model separately and also taking into account the mutual influence of these elements. Using the integrated model, five development scenarios were analyzed and an optimal scenario was chosen. The NPV of this scenario equals 7,277 mln RUR, cumulative gas production - 12,160.6 mln m3, cumulative condensate production - 1.8 mln tons.

  15. The thermal evolution of Cu nanoparticles condensed from the gas phase: MD simulations

    NASA Astrophysics Data System (ADS)

    Chepkasov, I. V.; Gafner, S. L.; Nomoev, A. V.; Bazarova, D. G.; Semenova, I. A.

    2016-02-01

    The gas-phase condensation of 85000 Cu atoms is examined by molecular dynamics simulation with a tight-binding potential. A detailed study of the evolution of the system cooled at a constant rate from 1000 K to 77 K is presented. The results are used to identify four distinct stages of the evolution from a hot atomic gas to a few synthesized particles. The effect of the subsequent thermal treatment on the shape and structure of synthesized particles was studied by simulating their gradual heating in a range of 100-1200 K. It is concluded that short-term heating leads to significant ordering of the internal structure in 70% of agglomerated nanoparticles with the predominant formation of spherical shapes. In order to explain this result, the main mechanisms of cluster formation from the gas phase have been analyzed and it is found that the agglomeration temperature plays the main role in the formation of clusters with unified shape and structure.

  16. Pyrolysis process for producing condensed stabilized hydrocarbons utilizing a beneficially reactive gas

    DOEpatents

    Durai-Swamy, Kandaswamy

    1982-01-01

    In a process for recovery of values contained in solid carbonaceous material, the solid carbonaceous material is comminuted and then subjected to pyrolysis, in the presence of a carbon containing solid particulate source of heat and a beneficially reactive transport gas in a transport flash pyrolysis reactor, to form a pyrolysis product stream. The pyrolysis product stream contains a gaseous mixture and particulate solids. The solids are separated from the gaseous mixture to form a substantially solids-free gaseous stream which comprises volatilized hydrocarbon free radicals newly formed by pyrolysis. Preferably the solid particulate source of heat is formed by oxidizing part of the separated particulate solids. The beneficially reactive transport gas inhibits the reactivity of the char product and the carbon-containing solid particulate source of heat. Condensed stabilized hydrocarbons are obtained by quenching the gaseous mixture stream with a quench fluid which contains a capping agent for stabilizing and terminating newly formed volatilized hydrocarbon free radicals. The capping agent is partially depleted of hydrogen by the stabilization and termination reaction. Hydrocarbons of four or more carbon atoms in the gaseous mixture stream are condensed. A liquid stream containing the stabilized liquid product is then treated or separated into various fractions. A liquid containing the hydrogen depleted capping agent is hydrogenated to form a regenerated capping agent. At least a portion of the regenerated capping agent is recycled to the quench zone as the quench fluid. In another embodiment capping agent is produced by the process, separated from the liquid product mixture, and recycled.

  17. Application of sterane epimerization to evaluation of Yoshii gas and condensate reservoir, Niigata basin, Japan

    SciTech Connect

    Suzuki, Noriyuki )

    1990-10-01

    A practical method is used to assess maturation histories and paleotemperatures of mudstones. This method is based on 20R-C{sub 29} sterane epimerization and the apparent heating rate. A relationship among sterane epimerization, maximum burial temperature, and heating rate is determined assuming kinetic constants of sterane epimerization. This relationship is used to reconstruct the subsidence and thermal histories of mudstones and accumulated oils in the young Nishiyama/Chuo oil field (Tertiary-Quaternary). The estimated thickness of eroded sediments in the Haizume/Uonuma Formation, the uppermost rocks in the Nishiyama/Chuo oil field, indicate subsidence and heating rates of 2-4 km/m.y. and 80-160C/m.y., respectively, and uplift and cooling rates of 2-4 km/m.y. and 80-160C/m.y., respectively, during the late Quaternary. These rates suggest recent vigorous tectonism in the Niigata back-arc sedimentary basin. Based on geologic observations and maturation levels of crude oils, the oil generation threshold and primary migration stage correspond to degrees of sterane epimerization of 20S/(20S + 20R) = 0.20 to 0.35 and 20S/(20S + 20R) = 0.40 to 0.50, respectively. The anticlinal structure of Yoshi gas and condensate reservoir was formed prior to the late Pliocene. The thermal and subsidence histories of source rocks indicate that the accumulation of hydrocarbons in Yoshii reservoir rocks started in the Pleistocene. Further maturation of these reservoir rocks and the possible addition of gases from overmature source rocks during the late Quaternary resulted in formation of the Yoshii gas-condensate reservoir. Formation of anticlinal structure of Nishiyama reservoir began in the late Quaternary after the major stage of oil migration. Vigorous tectonism during the late Quaternary caused abrupt development of the anticline, allowing oil to accumulate to form Nishiyama reservoir.

  18. 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.

  19. Litho-facies and paleotectonic background of hydrocarbon reservoirs in North Kalinov gas-condensate field (Tomsk Oblast)

    NASA Astrophysics Data System (ADS)

    Ten, T. G.; Panova, E. V.; Abramova, R. N.

    2015-11-01

    Based on micro-macroscopic core analysis, geophysical field data, contour mapping and referencing detailed litho-facies and paleotectonic investigation of Upper Jurassic pay thickness in North Kalinov gas condensate field was conducted. Paleotectonic analysis reflected the structure development history and determined the formation and distribution of oil fields.

  20. A fluid property module for the TOUGH2 simulator for saline brines with non-condensible gas

    SciTech Connect

    Battistelli, A.; Calore, C.; Pruess, K.

    1993-01-28

    A new equation-of-state module has been developed for the TOUGH2 simulator, belonging to the MULKOM family of computer codes developed at LBL. This EOS module is able to handle three-component mixtures of water, sodium chloride, and a non-condensible gas. It can describe liquid and gas phases, and includes precipitation and dissolution of solid salt. The dependence of density, viscosity, enthalpy, and vapor pressure of brine on salt concentration is taken into account, as well as the effects of salinity on gas solubility in the liquid phase and related heat of solution. The main assumptions made in developing this EOS module are discussed, together with the correlations employed to calculate the thermophysical properties of multiphase multicomponent mixtures. At present the non-condensible gas can be chosen to be air, CO2, CH4, H2, or N2. This paper focuses on H2O-NaCI-CO2 mixtures and describes new correlations obtained from fitting of published experimental data. Illustrative results for geothermal reservoir depletion in the presence of salinity and non-condensible gas are presented. We demonstrate and analyze effects of vapor pressure lowering and gas solubility decrease from salinity, and loss of reservoir porosity and permeability from salt precipitation during boiling of brines.

  1. Origins of inert Higgs doublets

    NASA Astrophysics Data System (ADS)

    Kephart, Thomas W.; Yuan, Tzu-Chiang

    2016-05-01

    We consider beyond the standard model embedding of inert Higgs doublet fields. We argue that inert Higgs doublets can arise naturally in grand unified theories where the necessary associated Z2 symmetry can occur automatically. Several examples are discussed.

  2. Intrinsic bioremediation of petroleum hydrocarbons in a gas condensate-contaminated aquifer

    SciTech Connect

    Gieg, L.M.; McInerney; Tanner, R.S.; Harris, S.H. Jr.; Sublette, K.L.; Suflita, J.M. ); Kolhatkar, R.V. . Center for Environmental Research and Technology)

    1999-08-01

    A study was designed to determine if the intrinsic bioremediation of gas condensate hydrocarbons represented an important fate process in a shallow aquifer underlying a natural gas production site. For over 4 yr, changes in the groundwater, sediment, and vadose zone chemistry in the contaminated portion of the aquifer were interpreted relative to a background zone. Changes included decreased dissolved oxygen and sulfate levels and increased alkalinity, Fe(II), and methane concentrations in the contaminated groundwater, suggesting that aerobic heterotrophic respiration depleted oxygen reserves leaving anaerobic conditions in the hydrocarbon-impacted subsurface. Dissolved hydrogen levels in the contaminated groundwater indicated that sulfate reduction and methanogenesis were predominant biological processes, corroborating the geochemical findings. Furthermore, 10--1000-fold higher numbers of sulfate reducers and methanogens were enumerated in the contaminated sediment relative to background. Putative metabolites were also detected in the contaminated groundwater, including methylbenzylsuccinic acid, a signature intermediate of anaerobic xylene decay. Laboratory incubations showed that benzene, toluene, ethylbenzene, and each of the xylene isomers were biodegraded under sulfate-reducing conditions as was toluene under methanogenic conditions. These results coupled with a decrease in hydrocarbon concentrations in contaminated sediment confirm that intrinsic bioremediation contributes to the attenuation of hydrocarbons in this aquifer.

  3. Interstellar silicate analogs for grain-surface reaction experiments: Gas-phase condensation and characterization of the silicate dust grains

    SciTech Connect

    Sabri, T.; Jäger, C.; Gavilan, L.; Lemaire, J. L.; Vidali, G.; Henning, T.

    2014-01-10

    Amorphous, astrophysically relevant silicates were prepared by laser ablation of siliceous targets and subsequent quenching of the evaporated atoms and clusters in a helium/oxygen gas atmosphere. The described gas-phase condensation method can be used to synthesize homogeneous and astrophysically relevant silicates with different compositions ranging from nonstoichiometric magnesium iron silicates to pyroxene- and olivine-type stoichiometry. Analytical tools have been used to characterize the morphology, composition, and spectral properties of the condensates. The nanometer-sized silicate condensates represent a new family of cosmic dust analogs that can generally be used for laboratory studies of cosmic processes related to condensation, processing, and destruction of cosmic dust in different astrophysical environments. The well-characterized silicates comprising amorphous Mg{sub 2}SiO{sub 4} and Fe{sub 2}SiO{sub 4}, as well as the corresponding crystalline silicates forsterite and fayalite, produced by thermal annealing of the amorphous condensates, have been used as real grain surfaces for H{sub 2} formation experiments. A specifically developed ultra-high vacuum apparatus has been used for the investigation of molecule formation experiments. The results of these molecular formation experiments on differently structured Mg{sub 2}SiO{sub 4} and Fe{sub 2}SiO{sub 4} described in this paper will be the topic of the next paper of this series.

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

    DOEpatents

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

  5. Condensed-phase versus gas-phase ozonolysis of catechol: A combined experimental and theoretical study

    NASA Astrophysics Data System (ADS)

    Barnum, Timothy J.; Medeiros, Nicholas; Hinrichs, Ryan Z.

    2012-08-01

    Anthropogenic emissions of volatile aromatic compounds contribute to the formation of secondary organic aerosols (SOA), especially in urban environments. Aromatic SOA precursors typically require oxidation by hydroxyl radicals, although recent work suggests that ozonolysis of 1,2-benzenediols produces SOA in high yields. We employed attenuated total reflectance and transmission infrared spectroscopy to investigate the heterogeneous ozonolysis of catechol thin films. Formation of the dominant condensed-phase product muconic acid was highly dependent on relative humidity (RH) with few products detected below 40% RH and a maximum reactive uptake coefficient of γ = (5.6 ± 0.5) × 10-5 measured at 81.2% RH. We also performed quantum chemical calculations mapping out several reaction pathways for the homogeneous ozonolysis of gaseous catechol. 1,3-cycloaddition transition states were rate limiting with the most favorable activation energies at 45.4 and 47.1 kJ mol-1 [CCSD(T)/6-311++G(d,p)] corresponding to addition across and adjacent to the diol Cdbnd C, respectively. Gas-phase rate constants, calculated using transition state theory, were six orders of magnitude slower than experimental values. In contrast, a calculated activation energy was lower for the ozonolysis of a catechol•H2O complex, which serves as a first-approximation for modeling the ozonolysis of condensed-phase catechol. These combined results suggests that homogeneous ozonolysis of catechol may not be important for the formation of secondary organic aerosols but that ozonolysis of surface-adsorbed catechol may contribute to SOA growth.

  6. Hydrocarbon habitat of San Martin and Cashiriari gas/condensate discoveries, southern Ucayali basin of Peru

    SciTech Connect

    Mohler, H.P.

    1989-03-01

    Fifteen trillion ft/sup 3/ of wet gas in place containing some 800 million bbl of associated liquids have been discovered in the San Martin and Cashiriari anticlines, which are located in the Subandean thrusted foldbelt of the Southern Ucayali basin of Peru. Ultimate recoverable volumes are estimated at 10 trillion ft/sup 3/ of gas and 500 million bbl of liquids including condensate (C5+) and LPG (C3/C4). Most of these potentially recoverable reserves are located in the Cashiriari structure (80% of the gas and 70% of the liquids). They were encountered in fair-excellent sandstone reservoirs of Early Permian and Late Cretaceous age and are thought to be derived from Carboniferous coaly shale source rocks. The Paleozoic (pre-Andean) sedimentary megacycle is represented by deeper shallow marine clastics of Ordovician to Early Carboniferous age (5000 m maximum), including Silurian glaciomarine deposits, overlain by up to 1200 m of Permian-Carboniferous platform carbonates and 600-1000( ) m of Lower Permian-lower Upper Permian coastal-continental clastics. The Mesozoic-Tertiary (Andean) megacycle is represented by a Campanian-Maastrichtian transgressive marine clastic/carbonate and overlying regressive clastic sequence (450 m maximum), followed by several thousand meters of Molasse-type continental infill of the Tertiary foredeep, which was created by the crustal loading in the wake of the compressional Andean orogeny (Peru, Inca, and Quechua phases). Late Tertiary folding and thrusting of the sub-Andean belt was superseded by regional Pleistocene uplift, and parts of the foreland continue to subside.

  7. User's manual for the TRW gaspipe 2 program: A vapor-gas front analysis program for heat pipes containing non-condensible gas

    NASA Technical Reports Server (NTRS)

    Edwards, D. K.; Fleischman, G. L.; Marcus, B. D.

    1973-01-01

    A digital computer program for design and analysis of heat pipes which contain non-condensible gases, either for temperature control or to aid in start-up from the frozen state, is presented. Some of the calculations which are possible with the program are: (1) wall temperature profile along a gas-loaded heat pipe, (2) amount of gas loading necessary to obtain desired evaporator temperature at a desired heat load, (3) heat load versus evaporator temperature for a fixed amount of gas in the pipe, and (4) heat and mass transfer along the pipe, including the vapor-gas front region.

  8. Core acid treatment influence on well reservoir properties in Kazan oil-gas condensate field

    NASA Astrophysics Data System (ADS)

    Janishevskii, A.; Ezhova, A.

    2015-11-01

    The research involves investigation of the influence of hydrochloric acid (HCI-12%) and mud acid (mixture: HCl - 10% and HF - 3%) treatment on the Upper-Jurassic reservoir properties in Kazan oil-gas condensate field wells. The sample collection included three lots of core cylinders from one and the same depth (all in all 42). Two lots of core cylinders were distributed as following: first lot - reservoir properties were determined, and, then thin sections were cut off from cylinder faces; second lot- core cylinders were exposed to hydrochloric acid treatment, then, after flushing the reservoir properties were determined, and thin sections were prepared. Based on the quantitative petrographic rock analysis, involvin 42 thin sections, the following factors were determined: granulometric mineral composition, cement content, intergranular contacts and pore space structure. According to the comparative analysis of initial samples, the following was determined: content decrease of feldspar, clay and mica fragments, mica, clay and carbonate cement; increase of pore spaces while in the investigated samples- on exposure of rocks to acids effective porosity and permeability value range is ambiguous.

  9. Astrophysical Lasers in Optical Fe II Lines in Gas Condensations near η Carinae

    NASA Astrophysics Data System (ADS)

    Johansson, S.; Letokhov, V. S.

    2005-05-01

    We report here on the discovery of laser action in the range 0.9-2 μm in several spectral lines of Fe II, which are associated with transitions from ``pseudo-metastable'' states populated by spontaneous transitions from Lyα pumped Fe II levels. The intense Lyα radiation is formed in the HII region of gas condensations close to the star η Car. The laser transitions form together with spontaneous transitions closed radiative cycles, one of which includes the extremely bright 2507/09 Å lines. This fact, together with an accidental mixing of energy levels, may provide an explanation of the abnormal intensities of these UV non-lasing lines. Using the complicated energy level diagram of Fe II we present those peculiar features, which are essential for the inverted population and laser effect: the pumping, the level mixing, and the ``bottle neck'' for spontaneous decay. The laser action is a new indicator of non-equilibrium and spatially non-homogeneous physical conditions as well as a high brightness temperature of Lyα in ejecta from eruptive stars. Such conditions are very difficult to probe by existing methods.

  10. In situ measurements of plasma properties during gas-condensation of Cu nanoparticles

    NASA Astrophysics Data System (ADS)

    Koten, M. A.; Voeller, S. A.; Patterson, M. M.; Shield, J. E.

    2016-03-01

    Since the mean, standard deviation, and modality of nanoparticle size distributions can vary greatly between similar input conditions (e.g., power and gas flow rate), plasma diagnostics were carried out in situ using a double-sided, planar Langmuir probe to determine the effect the plasma has on the heating of clusters and their final size distributions. The formation of Cu nanoparticles was analyzed using cluster-plasma physics, which relates the processes of condensation and evaporation to internal plasma properties (e.g., electron temperature and density). Monitoring these plasma properties while depositing Cu nanoparticles with different size distributions revealed a negative correlation between average particle size and electron temperature. Furthermore, the modality of the size distributions also correlated with the modality of the electron energy distributions. It was found that the maximum cluster temperature reached during plasma heating and the material's evaporation point regulates the growth process inside the plasma. In the case of Cu, size distributions with average sizes of 8.2, 17.3, and 24.9 nm in diameter were monitored with the Langmuir probe, and from the measurements made, the cluster temperatures for each deposition were calculated to be 1028, 1009, and 863 K. These values are then compared with the onset evaporation temperature of particles of this size, which was estimated to be 1059, 1068, and 1071 K. Thus, when the cluster temperature is too close to the evaporation temperature, less particle growth occurs, resulting in the formation of smaller particles.

  11. Effect of a condensation utilizer on the operation of steam and hot-water gas-fired boilers

    NASA Astrophysics Data System (ADS)

    Ionkin, I. L.; Ragutkin, A. V.; Roslyakov, P. V.; Supranov, V. M.; Zaichenko, M. N.; Luning, B.

    2015-05-01

    Various designs for condensation utilizers of the low-grade heat of furnace gases that are constructed based on an open-type heat exchanger are considered. Computational investigations are carried out for the effect of the condensation utilizer with tempering and moistening of air on the operation of steam and hot-water boilers burning natural gas. The investigations are performed based on the predeveloped adequate calculating models of the steam and hot-water boilers in a Boiler Designer program complex. Investigation results for TGM-96B and PTVM-120 boilers are given. The enhancement of the operation efficiency of the condensation utilizer can be attained using a design with tempering and moistening of air supplied to combustion that results in an insignificant increase in the temperature of waste gases. This has no effect on the total operation efficiency of the boiler and the condenser unit, because additional losses with waste gases are compensated owing to the operation of the last. The tempering and moistening of air provide a substantial decrease in the temperature in the zone of active combustion and shortening the nitrogen oxide emission. The computational investigations show that the premoistening of air supplied to combustion makes the technical and economic efficiency of boilers operating with the Condensation Utilizer no worse.

  12. Studies on pressure response of gas bubbles contributions of condensed droplets in bubbles generated by a uniform nucleation

    NASA Technical Reports Server (NTRS)

    Matsumoto, Y.

    1988-01-01

    The response of a tiny gas bubble under reduced pressure is investigated in its relation to cavitation. Equations of motion are formulated for gas mixtures inside the bubble and numerical calculations performed for several examples. The conclusions are as follows: (1) at the onset of bubble growth, the gas mixture inside it adiabatically expands and the temperature decreases. Condensed droplets appear inside the gas mixture due to a uniform nucleation and the temperature recovers, thus the motion of the bubble is apparently isothermal; (2) the evaporation and condensation coefficient largely affects bubble motions (maximum radius, period and rate of attenuation of the bubble oscillation) including the uniform contraction; (3) the oscillation period of the bubble is longer as the equilibrium bubble radius is larger when the surrounding pressure decreases stepwise. In this circumstance the temperature inside the bubble is kept constant due to condensation evaporation phenomena and is nearly isothermal; and (4) when the surrounding pressure decreases in a stepwise fashion, the critical pressure bubble radius relation becomes closer to that for the isothermal process if the bubble radius is larger than 8 microns.

  13. Pore diameter effects on phase behavior of a gas condensate in graphitic one-and two-dimensional nanopores.

    PubMed

    Welch, William R W; Piri, Mohammad

    2016-01-01

    Molecular dynamics (MD) simulations were performed on a hydrocarbon mixture representing a typical gas condensate composed mostly of methane and other small molecules with small fractions of heavier hydrocarbons, representative of mixtures found in tight shale reservoirs. The fluid was examined both in bulk and confined to graphitic nano-scale slits and pores. Numerous widths and diameters of slits and pores respectively were examined under variable pressures at 300 K in order to find conditions in which the fluid at the center of the apertures would not be affected by capillary condensation due to the oil-wet walls. For the bulk fluid, retrograde phase behavior was verified by liquid volumes obtained from Voronoi tessellations. In cases of both one and two-dimensional confinement, for the smallest apertures, heavy molecules aggregated inside the pore space and compression of the gas outside the solid structure lead to decreases in density of the confined fluid. Normal density/pressure relationships were observed for slits having gaps of above 3 nm and pores having diameters above 6 nm. At 70 bar, the minimum gap width at which the fluid could pass through the center of slits without condensation effects was predicted to be 6 nm and the corresponding diameter in pores was predicted to be 8 nm. The models suggest that in nanoscale networks involving pores smaller than these limiting dimensions, capillary condensation should significantly impede transmission of natural gases with similar composition. PMID:26733485

  14. Study of materials to resist corrosion in condensing gas fired furnaces. Annual report Oct 79-Oct 80

    SciTech Connect

    Lahtvee, T.; Khoo, S.W.; Schaus, O.O.

    1981-02-01

    Based on a thorough review of background information on the performance of materials in condensing gas-fired furnace heat exchangers and in similar corrosive environments, candidate materials were selected and tested on one of two identical test rigs built to provide the varying corrosive conditions encountered in an actual gas-fired condensing system heat exchanger. The 32 different materials tested in a one month screening test included: mild, low alloy, galvanized, solder coated and CaCO3 dipped galvanized steel, porcelain, epoxy, teflon and nylon coated and alonized mild steel; austenitic, ferritic, low interstitial Ti stabilized ferritic, and high alloy stainless steels; aluminum alloy anodized and porcelain coated aluminum; copper and cupronickel alloys, solder coated copper; and titanium.

  15. Sublimating comets as the source of nucleation seeds for grain condensation in the gas outflow from AGB stars

    NASA Technical Reports Server (NTRS)

    Whitmire, D. P.; Matese, John J.; Reynolds, R. T.

    1989-01-01

    A growing amount of observational and theoretical evidence suggests that most main sequence stars are surrounded by disks of cometary material. The dust production by comets in such disks is investigated when the central stars evolve up the red giant and asymptotic giant branch (AGB). Once released, the dust is ablated and accelerated by the gas outflow and the fragments become the seeds necessary for condensation of the gas. The origin of the requisite seeds has presented a well known problem for classical nucleation theory. This model is consistent with the dust production observed in M giants and supergiants (which have increasing luminosities) and the fact that earlier supergiants and most WR stars (whose luminosities are unchanging) do not have significant dust clouds even though they have significant stellar winds. Another consequence of the model is that the spatial distribution of the dust does not, in general, coincide with that of the gas outflow, in contrast to the conventional condensation model. A further prediction is that the condensation radius is greater that that predicted by conventional theory which is in agreement with IR interferometry measurements of alpha-Ori.

  16. Gas phase condensation of superparamagnetic iron oxide-silica nanoparticles - control of the intraparticle phase distribution

    NASA Astrophysics Data System (ADS)

    Stötzel, C.; Kurland, H.-D.; Grabow, J.; Müller, F. A.

    2015-04-01

    Spherical, softly agglomerated and superparamagnetic nanoparticles (NPs) consisting of maghemite (γ-Fe2O3) and amorphous silica (SiO2) were prepared by CO2 laser co-vaporization (CoLAVA) of hematite powder (α-Fe2O3) and quartz sand (SiO2). The α-Fe2O3 portion of the homogeneous starting mixtures was gradually increased (15 mass%-95 mass%). It was found that (i) with increasing iron oxide content the NPs' morphology changes from a nanoscale SiO2 matrix with multiple γ-Fe2O3 inclusions to Janus NPs consisting of a γ-Fe2O3 and a SiO2 hemisphere to γ-Fe2O3 NPs each carrying one small SiO2 lens on its surface, (ii) the multiple γ-Fe2O3 inclusions accumulate at the NPs' inner surfaces, and (iii) all composite NPs are covered by a thin layer of amorphous SiO2. These morphological characteristics are attributed to (i) the phase segregation of iron oxide and silica within the condensed Fe2O3-SiO2 droplets, (ii) the temperature gradient within these droplets which arises during rapid cooling in the CoLAVA process, and (iii) the significantly lower surface energy of silica when compared to iron oxide. The proposed growth mechanism of these Fe2O3-SiO2 composite NPs during gas phase condensation can be transferred to other systems comprising a glass-network former and another component that is insoluble in the regarding glass. Thus, our model will facilitate the development of novel functional composite NPs for applications in biomedicine, optics, electronics, or catalysis.Spherical, softly agglomerated and superparamagnetic nanoparticles (NPs) consisting of maghemite (γ-Fe2O3) and amorphous silica (SiO2) were prepared by CO2 laser co-vaporization (CoLAVA) of hematite powder (α-Fe2O3) and quartz sand (SiO2). The α-Fe2O3 portion of the homogeneous starting mixtures was gradually increased (15 mass%-95 mass%). It was found that (i) with increasing iron oxide content the NPs' morphology changes from a nanoscale SiO2 matrix with multiple γ-Fe2O3 inclusions to Janus NPs consisting of a γ-Fe2O3 and a SiO2 hemisphere to γ-Fe2O3 NPs each carrying one small SiO2 lens on its surface, (ii) the multiple γ-Fe2O3 inclusions accumulate at the NPs' inner surfaces, and (iii) all composite NPs are covered by a thin layer of amorphous SiO2. These morphological characteristics are attributed to (i) the phase segregation of iron oxide and silica within the condensed Fe2O3-SiO2 droplets, (ii) the temperature gradient within these droplets which arises during rapid cooling in the CoLAVA process, and (iii) the significantly lower surface energy of silica when compared to iron oxide. The proposed growth mechanism of these Fe2O3-SiO2 composite NPs during gas phase condensation can be transferred to other systems comprising a glass-network former and another component that is insoluble in the regarding glass. Thus, our model will facilitate the development of novel functional composite NPs for applications in biomedicine, optics, electronics, or catalysis. Electronic supplementary information (ESI) available: Infrared absorption of the raw powders hematite and quartz (section S1), TEM investigation of the spatial distribution of the γ-Fe2O3 inclusions (section S2), particle size distributions of the Fe2O3@SiO2 nanopowder samples (section S3), ζ-potentials of aqueous dispersions of all γ-Fe2O3@SiO2 nanopowder samples (section S4), silanization of Fe2O3@SiO2 composite nanopowders with [3-(2,3-epoxypropoxy)-propyl]trimethoxysilane (section S5), and animation composed of TEM micrographs of Fe2O3@SiO2 NPs recorded at incrementally altered tilt angles (``Rotating Fe2O3@SiO2 NP.avi''). See DOI: 10.1039/c5nr00845j

  17. Interpretation of pressure transient data from hydraulically fractured gas condensate wells

    SciTech Connect

    Yadavalli, S.K.; Jones, J.R.

    1996-12-31

    The possible range of, and the application of standard single phase interpretation methods to, the pressure transient responses for hydraulically fractured wells producing gas-condensate fluids are examined in this paper. A fully implicit, EOS based, compositional model is used to generate buildup responses for various combinations of fracture half-lengths, fracture conductivities, fluid richness levels, rates, reservoir relative permeability curves and producing times. Though all the responses presented here assume that average reservoir pressure remains above the dewpoint of the initial fluid in situ, the sensitivity to the difference between the initial reservoir pressure and this dewpoint pressure is also investigated. The effects of Non-Darcy flow in the reservoir and/or the fracture, wellbore storage and capillary or Bond number dependent relative permeabilities are not considered. In addition, most of our results assume that the fracture proppant has straight line relative permeability characteristics. Some limited information, however, is presented where this assumption is relaxed. The results of this work indicated that these buildup responses can be separated into two basic categories depending on the specific values of the above parameters. In the first category, the derivative response shape is not noticeably different from that of a fractured well with fracture face skin. The second category is typified by a derivative shape dominated by a hump between the early fracture flow periods and the late pseudoradial flow periods. A method is presented for deriving reasonable estimates for true completion skin factors for responses in this category. The reliability of applying standard single-phase interpretation methods (straight line analyses and history matching) is documented for both categories of responses and error directions and magnitudes are given.

  18. 33 CFR 154.2107 - Inerting, enriching, and diluting systems.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... activates an alarm that satisfies the requirements of 33 CFR 154.2100(e) when the amount of enriching gas... diluting system must be equipped, except as permitted by 33 CFR 154.2105(a), with a gas injection and... point, if a combustion device is used to produce the inert gas; and (5) Have an alarm value in...

  19. Laboratory Scoping Tests Of Decontamination Of Hanford Waste Treatment Plant Low Activity Waste Off-Gas Condensate Simulant

    SciTech Connect

    Taylor-Pashow, Kathryn M.; Nash, Charles A.; Crawford, Charles L.; McCabe, Daniel J.; Wilmarth, William R.

    2014-01-21

    The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream (LAW Off-Gas Condensate) from the off-gas system. The baseline plan for disposition of this stream is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility again. Alternate disposition of this stream would eliminate recycling of problematic components, and would enable de-coupled operation of the LAW melter and the Pretreatment Facilities. Eliminating this stream from recycling within WTP would also decrease the LAW vitrification mission duration and quantity of glass waste. This LAW Off-Gas Condensate stream contains components that are volatile at melter temperatures and are problematic for the glass waste form. Because this stream recycles within WTP, these components accumulate in the Condensate stream, exacerbating their impact on the number of LAW glass containers that must be produced. Approximately 32% of the sodium in Supplemental LAW comes from glass formers used to make the extra glass to dilute the halides to acceptable concentrations in the LAW glass, and diverting the stream reduces the halides in the recycled Condensate and is a key outcome of this work. Additionally, under possible scenarios where the LAW vitrification facility commences operation prior to the WTP Pretreatment facility, identifying a disposition path becomes vitally important. This task seeks to examine the potential treatment of this stream to remove radionuclides and subsequently disposition the decontaminated stream elsewhere, such as the Effluent Treatment Facility (ETF), for example. The treatment process envisioned is very similar to that used for the Actinide Removal Process (ARP) that has been operating for years at the Savannah River Site (SRS), and focuses on using mature radionuclide removal technologies that are also compatible with longterm tank storage and immobilization methods. For this new application, testing is needed to demonstrate acceptable treatment sorbents and precipitating agents and measure decontamination factors for additional radionuclides in this unique waste stream. The origin of this LAW Off-Gas Condensate stream will be the liquids from the Submerged Bed Scrubber (SBS) and the Wet Electrostatic Precipitator (WESP) from the LAW melter off-gas system. The stream is expected to be a dilute salt solution with near neutral pH, and will likely contain some insoluble solids from melter carryover. The soluble components are expected to be mostly sodium and ammonium salts of nitrate, chloride, and fluoride. This stream has not been generated yet and will not be available until the WTP begins operation, but a simulant has been produced based on models, calculations, and comparison with pilot-scale tests. One of the radionuclides that is volatile and expected to be in high concentration in this LAW Off-Gas Condensate stream is Technetium-99 ({sup 99}Tc). Technetium will not be removed from the aqueous waste in the Hanford WTP, and will primarily end up immobilized in the LAW glass by repeated recycle of the off-gas condensate into the LAW melter. Other radionuclides that are also expected to be in appreciable concentration in the LAW Off-Gas Condensate are {sup 129}I, {sup 90}Sr, {sup 137}Cs, and {sup 241}Am. This report discusses results of preliminary radionuclide decontamination testing of the simulant. Testing examined use of Monosodium Titanate (MST) to remove {sup 90}Sr and actinides, inorganic reducing agents for {sup 99}Tc, and zeolites for {sup 137}Cs. Test results indicate that excellent removal of {sup 99}Tc was achieved using Sn(II)Cl{sub 2} as a reductant, coupled with sorption onto hydroxyapatite, even in the presence of air and at room temperature. This process was very effective at neutral pH, with a Decontamination Factor (DF) >577 in two hours. It was less effective at alkaline pH. Conversely, removal of the cesium was more effective at alkaline pH, with a DF of 17.9. As anticipated, ammonium ion probably interfered with the Ionsiv®a IE-95 zeolite uptake of {sup 137}Cs. Although this DF of {sup 137}Cs was moderate, additional testing is expected to identify more effective conditions. Similarly, Monosodium Titanate (MST) was more effective at alkaline pH at removing Sr, Pu, and U, with a DF of 319, 11.6, and 10.5, respectively, within 24 hours. Actually, the Ionsiv® IE-95, which was targeting removal of Cs, was also moderately effective for Sr, and highly effective for Pu and U at alkaline pH. The only deleterious effect observed was that the chromium co-precipitates with the {sup 99}Tc during the SnCl{sub 2} reduction. This effect was anticipated, and would have to be considered when managing disposition paths of this stream. Results of this separation testing indicate that sorption/precipitation was a viable concept and has the potential to decontaminate the stream. All radionuclides were at least partially removed by one or more of the materials tested. Based on the results, a possible treatment scenario could involve the use of a reductive precipitation agent (SnCl{sub 2}) and sorbent at neutral pH to remove the Tc, followed by pH adjustment and the addition of zeolite (Ionsiv® IE-95) to remove the Cs, Sr, and actinides. Addition of MST to remove Sr and actinides may not be needed. Since this was an initial phase of testing, additional tasks to improve separation methods were expected to be identified. Primarily, further testing is needed to identify the conditions for the decontamination process. Once these conditions are established, follow-on tasks likely include evaluation and testing of applicable solid-liquid separation technologies, slurry rheology measurements, composition variability testing and evaluations, corrosion and erosion testing, slurry storage and immobilization investigations, and decontaminated LAW Off-Gas Condensate evaporation and solidification.

  20. 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, Ġ, 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.

  1. Compressing the inert doublet model

    NASA Astrophysics Data System (ADS)

    Blinov, Nikita; Kozaczuk, Jonathan; Morrissey, David E.; de la Puente, Alejandro

    2016-02-01

    The inert doublet model relies on a discrete symmetry to prevent couplings of the new scalars to Standard Model fermions. This stabilizes the lightest inert state, which can then contribute to the observed dark matter density. In the presence of additional approximate symmetries, the resulting spectrum of exotic scalars can be compressed. Here, we study the phenomenological and cosmological implications of this scenario. We derive new limits on the compressed inert doublet model from LEP, and outline the prospects for exclusion and discovery of this model at dark matter experiments, the LHC, and future colliders.

  2. Compressing the Inert Doublet Model

    SciTech Connect

    Blinov, Nikita; Morrissey, David E.; de la Puente, Alejandro

    2015-10-29

    The Inert Doublet Model relies on a discrete symmetry to prevent couplings of the new scalars to Standard Model fermions. We found that this stabilizes the lightest inert state, which can then contribute to the observed dark matter density. In the presence of additional approximate symmetries, the resulting spectrum of exotic scalars can be compressed. Here, we study the phenomenological and cosmological implications of this scenario. Furthermore, we derive new limits on the compressed Inert Doublet Model from LEP, and outline the prospects for exclusion and discovery of this model at dark matter experiments, the LHC, and future colliders.

  3. Direct synthesis of large size ferromagnetic SmCo{sub 5} nanoparticles by a gas-phase condensation method

    SciTech Connect

    He Shihai; Jing Ying; Wang Jianping

    2013-04-07

    Ferromagnetic SmCo{sub 5} nanoparticles with large size have been directly synthesized by a magnetron-sputtering-based gas-phase condensation method. Based on this method, we studied the effect of thermodynamic environment for the growth of SmCo{sub 5} nanoparticles. It was found that the well-crystallized SmCo{sub 5} nanoparticle tends to form a hexagonal disk shape with its easy axis perpendicular to the disk plane. More importantly, under the condition of high sputtering current, well-crystallized nanoparticles were found to be formed through a three-stage growth process: aggregation, coalescence, and second crystallization.

  4. AN INNOVATIVE TRANSPORT MEMBRANE CONDENSER WATER RECOVERY FROM FLUE GAS AND ITS REUSE - PHASE II

    EPA Science Inventory

    Although water recycle and reuse is considered good environmental practice, its implementation is highly dependent upon the economics and hence can be challenging to implement. An example is the recovery of low quality heat as water condensate from industrial flue gases. In th...

  5. Condensed tannin in drinking water reduces greenhouse gas precursor urea in sheep and cattle urine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ingestion of small amounts of naturally-occurring condensed tannin (CT) by ruminants can provide several benefits including potential reduction of ammonia and nitrous oxide emissions over the long-term by reducing their urine urea excretion. However, providing grazing ruminants with sufficient amou...

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

    PubMed

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

    2009-10-15

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

  7. Investigation into the determination of trimethylarsine in natural gas and its partitioning into gas and condensate phases using (cryotrapping)/gas chromatography coupled to inductively coupled plasma mass spectrometry and liquid/solid sorption techniques

    NASA Astrophysics Data System (ADS)

    Krupp, E. M.; Johnson, C.; Rechsteiner, C.; Moir, M.; Leong, D.; Feldmann, J.

    2007-09-01

    Speciation of trialkylated arsenic compunds in natural gas, pressurized and stable condensate samples from the same gas well was performed using (Cryotrapping) Gas Chromatography-Inductively Coupled Plasma Mass Spectrometry. The major species in all phases investigated was found to be trimethylarsine with a highest concentration of 17.8 ng/L (As) in the gas phase and 33.2 μg/L (As) in the stable condensate phase. The highest amount of trimethylarsine (121 μg/L (As)) was found in the pressurized condensate, along with trace amounts of non-identified higher alkylated arsines. Volatile arsenic species in natural gas and its related products cause concern with regards to environment, safety, occupational health and gas processing. Therefore, interest lies in a fast and simple field method for the determination of volatile arsenicals. Here, we use simple liquid and solid sorption techniques, namely absorption in silver nitrate solution and adsorption on silver nitrate impregnated silica gel tubes followed by total arsenic determination as a promising tool for field monitoring of volatile arsenicals in natural gas and gas condensates. Preliminary results obtained for the sorption-based methods show that around 70% of the arsenic is determined with these methods in comparison to volatile arsenic determination using GC-ICP-MS. Furthermore, an inter-laboratory- and inter-method comparison was performed using silver nitrate impregnated silica tubes on 14 different gas samples with concentrations varying from below 1 to 1000 μg As/m 3 natural gas. The results obtained from the two laboratories differ in a range of 10 to 60%, but agree within the order of magnitude, which is satisfactory for our purposes.

  8. Studies of cluster-assembled materials: From gas phase to condensed phase

    NASA Astrophysics Data System (ADS)

    Gao, Lin

    Clusters, defined as "a number of similar things that occur together" in Webster's dictionary, has different meanings depending on the given subject. To physicists and chemists, the word cluster means "a group of atoms or molecules formed by interactions ranging from very weak van der Waals interactions to strong ionic bonds." Unlike molecules, which are made by nature and are stable under ambient conditions, clusters discovered in a laboratory are often metastable. Molecules have specific stoichiometry, whereas the cluster's composition can usually be altered atom by atom. Thus, clusters can be taken as intrinsically "artificial molecules" with considerably more tunabilities in their properties. Research into the relative stability and instability of clusters has in recent years become a very active research area, especially following the study by Khanna and Castleman that first suggested that by varying size and composition, clusters can expand the periodic table to the 3 rd-dimension; that is, clusters can mimic the chemistry of atoms and may, therefore, be used as the building blocks of new materials. The discovery of Met-Cars has drawn worldwide interests and has been actively investigated by researchers from a variety of fields, including physics, chemistry and material science. However, the unsuccessful search for a solvent capable of isolating Met-Cars has impeded progress in characterizing the material in the condensed state and, hence, limited its potential applications as a novel nanoscale material. An alternative method involving the deposition of mass-gated species and the subsequent structural investigation via Transmission Electron Microscopy (TEM) has been employed. With particularly interesting results, soft-landed deposits of zirconium Met-Cars were found to form a face-centered-cubic (FCC) structure with a lattice parameter ˜ 15A. The production of Met-Cars is conducted with the direct laser vaporization (DLV) of metal/graphite composite pellets. After being mass gated in a reflectron equipped time-of-flight mass spectrometer (TOF-MS) and deposited onto TEM grids, the resultant specimens can be loaded onto high-resolution TEM investigation via electron diffraction. In conclusion, soft-landing of mass selected clusters has been shown to be a successful approach to obtain structural information on Zr-Met-Car cluster-assembled materials collected from the gas phase. TEM images indicate the richness of the morphologies associated with these cluster crystals. However, passivation methods are expected to be examined further to overcome the limited stabilities of these novel clusters. From this initial study, it's shown the promising opportunity to study other Met-Cars species and more cluster-based materials. Experimental results of reactions run with a solvothermal synthesis method obtained while searching for new Zr-C cluster assembled materials, are reported. One unexpected product in single crystal form was isolated and tentatively identified by X-ray diffraction to be [Zr6i O(OH)O12·2(Bu)4], with space group P2 1/n and lattice parameters of a = 12.44 A, b = 22.06 A, c = 18.40 A, alpha = 90°, beta = 105°, gamma = 90°, V = 4875 A3 and R 1 = 3.15% for the total observed data (I ≥ 2 sigma I) and oR2 = 2.82%. This novel hexanuclear Zr(IV)-oxo-hydroxide cluster anion may be the first member in polyoxometalates class with metal atoms from the IVB group and having Oh symmetry. Alternatively, it may be the first member in {[(Zr6Z)X 12]X6}m- class with halides replaced by oxo- and hydroxyl groups and with an increased oxidation state of Zr. It is predicted to bear application potentials directed by both families. This work could suggest a direction in which the preparation of Zr-C cluster-assembled materials in a liquid environment may be eventually fulfilled. 1,3-Bis(diethylphosphino)propane (depp) protected small gold clusters are studied via multiple techniques, including Electrospray Ionization Mass Spectrometry (ESI-MS), Ultraviolet-Visible Spectroscopy (Uv-Vis), Nuclear Magnetic Resonance (NMR) for solution phase and Transmission Electron Microscopy (TEM) for the condensed phase. In particular, undeca-, dodeca- and trideca-gold clusters protected by depp and halogen ligands, i.e. [Au11-13(depp) 4Cl2-4]+, are found to be all predominant and persist in solution for months, while they gradually and spontaneously grow into a monomial trideca-gold clusters series. The unique preferred ligand combination, depp along with Cl, is discussed in terms of the ligand-core interaction and the closed-shell electronic configurations of the Au n (n = 11-13) cores, which enables them to serve as building units for larger cluster-assembled nanoparticles and form Self-Assembled Arrays (SAAs), as discovered by TEM measurements. Such spontaneous-growth behavior and the resultant SAAs observations are correlated by icosahedra-close-packing modes of clusters, following "magic numbers" rules. ˜7 shells of such cluster packing are proposed to be in the SAAs.

  9. Cloud Condensation in Titan's Lower Stratosphere

    NASA Technical Reports Server (NTRS)

    Romani, Paul N.; Anderson, Carrie M.

    2011-01-01

    A 1-D condensation model is developed for the purpose of reproducing ice clouds in Titan's lower stratosphere observed by the Composite Infrared Spectrometer (CIRS) onboard Cassini. Hydrogen cyanide (HCN), cyanoacetylene (HC3N), and ethane (C2H6) vapors are treated as chemically inert gas species that flow from an upper boundary at 500 km to a condensation sink near Titan's tropopause (-45 km). Gas vertical profiles are determined from eddy mixing and a downward flux at the upper boundary. The condensation sink is based upon diffusive growth of the cloud particles and is proportional to the degree of supersaturation in the cloud formation regIOn. Observations of the vapor phase abundances above the condensation levels and the locations and properties of the ice clouds provide constraints on the free parameters in the model. Vapor phase abundances are determined from CIRS mid-IR observations, whereas cloud particle sizes, altitudes, and latitudinal distributions are derived from analyses of CIRS far-IR observations of Titan. Specific cloud constraints include: I) mean particle radii of2-3 J.lm inferred from the V6 506 cm- band of HC3N, 2) latitudinal abundance distributions of condensed nitriles, inferred from a composite emission feature that peaks at 160/cm , and 3) a possible hydrocarbon cloud layer at high latitudes, located near an altitude of 60 km, which peaks between 60 and 80 cm l . Nitrile abundances appear to diminish substantially at high northern latitudes over the time period 2005 to 2010 (northern mid winter to early spring). Use of multiple gas species provides a consistency check on the eddy mixing coefficient profile. The flux at the upper boundary is the net column chemical production from the upper atmosphere and provides a constraint on chemical pathways leading to the production of these compounds. Comparison of the differing lifetimes, vapor phase transport, vapor phase loss rate, and particle sedimentation, sheds light on temporal stability of the clouds.

  10. Orgin and significance of geochemical variability among oils and gas-condensates in the Tiger Shoal Field, northern Gulf of Mexico

    SciTech Connect

    Kelley, P.A.; Imbus, S.W.; McKeever, S.R.

    1995-12-31

    Geochemical data placed in geological context is key to understanding the processes controlling the variability of oils and gas-condensates in the Tiger Shoal Field, northern Gulf of Mexico. Thermal maturity at generation and phase partitioning are the principal processes accounting for variability in the bulk and molecular properties of the oils and gas-condensates. Quantification of the extent that these processes altered the oils and gas-condensates between fault blocks and among individual sands permits: (1) documentation of the most effective migration conduits, (2) inference of deeper or shallower pay zones, (3) and assessment of vertical and lateral fluid connectivity. Calibration of bulk to molecular properties will permit rapid assessment of the type and extent of alteration using basic parameters such as API gravity and gas oil ratio (GOR). Upon mass balancing with initial reserves data, a detailed risking scheme for remaining prospects within the field can be formulated.

  11. Synthesis of fluorinated nano-silica and its application in wettability alteration near-wellbore region in gas condensate reservoirs

    NASA Astrophysics Data System (ADS)

    Mousavi, M. A.; Hassanajili, Sh.; Rahimpour, M. R.

    2013-05-01

    Fluorinated silica nanoparticles were prepared to alter rock wettability near-wellbore region in gas condensate reservoirs. Hence fluorinated silica nanoparticles with average diameter of about 80 nm were prepared and used to alter limestone core wettability from highly liquid-wet to intermediate gas-wet state. Water and n-decane contact angles for rock were measured before and after treatment. The contact angle measured 147° for water and 61° for n-decane on the core surface. The rock surface could not support the formation of any water or n-decane droplets before treatment. The functionalized fluorinated silica nanoparticles have been confirmed by the Csbnd F bond along with Sisbnd Osbnd Si bond as analyzed by FT-IR. The elemental composition of treated limestone core surface was determined using energy dispersive X-ray spectroscopy analyses. The final evaluation of the fluorinated nanosilica treatment in terms of its effectiveness was measured by core flood experimental tests.

  12. Origin of saline, neutral-pH, reduced epithermal waters by reaction of acidic magmatic gas condensates with wall rock

    SciTech Connect

    Reed, M.H. . Dept. of Geological Sciences)

    1993-04-01

    Fluid inclusions in quartz and sphalerite of epithermal veins containing galena, sphalerite and chalcopyrite with silver sulfides and electrum commonly have salinities of 2 to 10 weight percent NaCl equivalent. Examples include Bohemia, OR, Comstock, NV, and Creede, CO. Salinities in such base metal-rich systems are apparently greater than those in gold-adularia, base metal-poor systems such as Sleeper, NV, Republic, WA, and Hishikare, Kyushu. Saline epithermal fluids are commonly assumed to have been derived from saline magmatic brines, from local host formations, as has been suggested for Creede, or from evaporative concentration (boiling) of more dilute meteoric ground water. Another possibility, which may be the most common origin, is reaction of wall rocks with magmatic gas condensates rich in HCl and sulfuric acid. A mixture of one part Augustine Volcanic gas condensate in 10 parts cold ground water has a pH of 0.7 and the dominant cation is H[sup +] by a factor of 10[sup 4]. Calculated reaction of this condensate mixture with andesite at 300 C to a water/rock ratio (w/r) of 4.6 yields an NaCl-dominated fluid with a total salinity of 2.1 wt %. and pH 3.7. Further reaction, to w/r 0.14 yields a fluid salinity of 2.6 wt % and pH of 5.7; this fluid is in equilibrium with a propylitic alteration assemblage. Aqueous sulfide accumulates during the rock reaction as sulfate is reduced to sulfide when ferrous iron is oxidized to ferric iron. Sulfide concentration in the latter fluid is 32 ppm, far exceeding sulfate concentration. In the overall reaction, hydrogen ion is exchanged for base cations (including base metals) and sulfate is reduced to sulfide.

  13. 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

  14. Large Scale Gas Mixing and Stratification Triggered by a Buoyant Plume With and Without Occurrence of Condensation

    SciTech Connect

    Paladino, Domenico; Auban, Olivier; Zboray, Robert

    2006-07-01

    The benefits of using codes with 3-D capabilities to address safety issues of LWRs will be applicable to both the current generation of nuclear reactors as well to future ALWRs. The phenomena governing the containment response in case of some postulated severe accident scenarios include gas (air, hydrogen, steam) stratification in the containment, gas distribution between containment compartments, wall condensation, etc. These phenomena are driven by buoyant high momentum injection (jets) and/or low momentum injection (plumes). For instance, mixing in the immediate vicinity of the postulated line break is mainly dominated by very high velocity efflux, while low-momentum flows are responsible for most of the transport processes within the containment. A project named SETH is currently in progress under the auspices of 15 OECD countries, with the aim of creating an experimental database suitable to assess the 3-D code capabilities in analyzing key-physical phenomena relevant for LWR safety analysis. This paper describes some results of two SETH tests, performed in the PANDA facility (located at PSI in Switzerland), focusing on plumes flowing near a containment wall. The plumes are generated by injecting a constant amount of steam in one of two interconnected vessels initially filled with air. In one of the two tests the temperature of the injected steam and the initial containment wall and fluid temperatures allowed for condensation during the test. (authors)

  15. Metallofullerene and fullerene formation from condensing carbon gas under conditions of stellar outflows and implication to stardust

    PubMed Central

    Dunk, Paul W.; Adjizian, Jean-Joseph; Kaiser, Nathan K.; Quinn, John P.; Blakney, Gregory T.; Ewels, Christopher P.; Marshall, Alan G.; Kroto, Harold W.

    2013-01-01

    Carbonaceous presolar grains of supernovae origin have long been isolated and are determined to be the carrier of anomalous 22Ne in ancient meteorites. That exotic 22Ne is, in fact, the decay isotope of relatively short-lived 22Na formed by explosive nucleosynthesis, and therefore, a selective and rapid Na physical trapping mechanism must take place during carbon condensation in supernova ejecta. Elucidation of the processes that trap Na and produce large carbon molecules should yield insight into carbon stardust enrichment and formation. Herein, we demonstrate that Na effectively nucleates formation of Na@C60 and other metallofullerenes during carbon condensation under highly energetic conditions in oxygen- and hydrogen-rich environments. Thus, fundamental carbon chemistry that leads to trapping of Na is revealed, and should be directly applicable to gas-phase chemistry involving stellar environments, such as supernova ejecta. The results indicate that, in addition to empty fullerenes, metallofullerenes should be constituents of stellar/circumstellar and interstellar space. In addition, gas-phase reactions of fullerenes with polycyclic aromatic hydrocarbons are investigated to probe “build-up” and formation of carbon stardust, and provide insight into fullerene astrochemistry. PMID:24145444

  16. Metallofullerene and fullerene formation from condensing carbon gas under conditions of stellar outflows and implication to stardust.

    PubMed

    Dunk, Paul W; Adjizian, Jean-Joseph; Kaiser, Nathan K; Quinn, John P; Blakney, Gregory T; Ewels, Christopher P; Marshall, Alan G; Kroto, Harold W

    2013-11-01

    Carbonaceous presolar grains of supernovae origin have long been isolated and are determined to be the carrier of anomalous (22)Ne in ancient meteorites. That exotic (22)Ne is, in fact, the decay isotope of relatively short-lived (22)Na formed by explosive nucleosynthesis, and therefore, a selective and rapid Na physical trapping mechanism must take place during carbon condensation in supernova ejecta. Elucidation of the processes that trap Na and produce large carbon molecules should yield insight into carbon stardust enrichment and formation. Herein, we demonstrate that Na effectively nucleates formation of Na@C60 and other metallofullerenes during carbon condensation under highly energetic conditions in oxygen- and hydrogen-rich environments. Thus, fundamental carbon chemistry that leads to trapping of Na is revealed, and should be directly applicable to gas-phase chemistry involving stellar environments, such as supernova ejecta. The results indicate that, in addition to empty fullerenes, metallofullerenes should be constituents of stellar/circumstellar and interstellar space. In addition, gas-phase reactions of fullerenes with polycyclic aromatic hydrocarbons are investigated to probe "build-up" and formation of carbon stardust, and provide insight into fullerene astrochemistry. PMID:24145444

  17. LABORATORY OPTIMIZATION TESTS OF TECHNETIUM DECONTAMINATION OF HANFORD WASTE TREATMENT PLANT LOW ACTIVITY WASTE OFF-GAS CONDENSATE SIMULANT

    SciTech Connect

    Taylor-Pashow, K.; Nash, C.; McCabe, D.

    2014-09-29

    The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream (LAW Off-Gas Condensate) from the off-gas system. The baseline plan for disposition of this stream is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility again. Alternate disposition of this stream would eliminate recycling of problematic components, and would enable de-coupled operation of the LAW melter and the Pretreatment Facilities. Eliminating this stream from recycling within WTP would also decrease the LAW vitrification mission duration and quantity of glass waste. This LAW Off-Gas Condensate stream contains components that are volatile at melter temperatures and are problematic for the glass waste form. Because this stream recycles within WTP, these components accumulate in the Condensate stream, exacerbating their impact on the number of LAW glass containers that must be produced. Approximately 32% of the sodium in Supplemental LAW comes from glass formers used to make the extra glass to dilute the halides to acceptable concentrations in the LAW glass, and diverting the stream reduces the halides in the recycled Condensate and is a key outcome of this work. Additionally, under possible scenarios where the LAW vitrification facility commences operation prior to the WTP Pretreatment facility, identifying a disposition path becomes vitally important. This task examines the potential treatment of this stream to remove radionuclides and subsequently disposition the decontaminated stream elsewhere, such as the Effluent Treatment Facility (ETF), for example. The treatment process envisioned is very similar to that used for the Actinide Removal Process (ARP) that has been operating for years at the Savannah River Site (SRS), and focuses on using mature radionuclide removal technologies that are also compatible with longterm tank storage and immobilization methods. For this new application, testing is needed to demonstrate acceptable treatment sorbents and precipitating agents and measure decontamination factors for additional radionuclides in this unique waste stream. The origin of this LAW Off-Gas Condensate stream will be the liquids from the Submerged Bed Scrubber (SBS) and the Wet Electrostatic Precipitator (WESP) from the LAW melter off-gas system. The stream is expected to be a dilute salt solution with near neutral pH, and will likely contain some insoluble solids from melter carryover. The soluble components are expected to be mostly sodium and ammonium salts of nitrate, chloride, and fluoride. This stream has not been generated yet and will not be available until the WTP begins operation, but a simulant has been produced based on models, calculations, and comparison with pilot-scale tests. One of the radionuclides that is volatile and expected to be in greatest abundance in this LAW Off-Gas Condensate stream is Technetium-99 ({sup 99}Tc). Technetium will not be removed from the aqueous waste in the Hanford WTP, and will primarily end up immobilized in the LAW glass by repeated recycle of the off-gas condensate into the LAW melter. Other radionuclides that are low but are also expected to be in measurable concentration in the LAW Off-Gas Condensate are {sup 129}I, {sup 90}Sr, {sup 137}Cs, {sup 241}Pu, and {sup 241}Am. These are present due to their partial volatility and some entrainment in the off-gas system. This report discusses results of optimized {sup 99}Tc decontamination testing of the simulant. Testing examined use of inorganic reducing agents for {sup 99}Tc. Testing focused on minimizing the quantity of sorbents/reactants added, and minimizing mixing time to reach the decontamination targets in this simulant formulation. Stannous chloride and ferrous sulfate were tested as reducing agents to determine the minimum needed to convert soluble pertechnetate to the insoluble technetium dioxide. The reducing agents were tried with and without sorbents. The sorbents, hydroxyapatite and sodium oxalate, were expected to sorb the precipitated technetium dioxide and facilitate removal. The Phase 1 tests examined a broad range of conditions and used the initial baseline simulant. The Phase 2 tests narrowed the conditions based on Phase 1 results, and used a slightly modified simulant. Test results indicate that excellent removal of {sup 99}Tc was achieved using SnCl{sub 2} as a reductant, and was effective with or without sorption onto hydroxyapatite. This reaction worked even in the presence of air (which could oxidize the stannous ion) and at room temperature. This process was very effective at neutral pH, with a Decontamination Factor (DF) >199 in one hour with only 1 g/L of SnCl{sub 2}. Prior work had shown that it was much less effective at alkaline pH. The only deleterious effect observed was that the chromium co-precipitates with the {sup 99}c during the SnCl{sub 2} reduction. This effect was anticipated, and would have to be considered when managing disposition paths of this stream. Reduction using FeSO{sub 4} was not effective at removing {sup 99}Tc, but did remove the Cr. Chromium is present due to partial volatility and entrainment in the off-gas, and is highly oxidizing, so would be expected to react with reducing agents more quickly than pertechnetate. Testing showed that sufficient reducing agent must be added to completely reduce the chromium before the technetium is reduced and removed. Other radionuclides are also present in this off-gas condensate stream. To enable sending this stream to the Hanford ETF, and thereby divert it from the recycle where it impacts the LAW glass volume, several of these also need to be removed. Samples from optimized conditions were also measured for actinide removal in order to examine the effect of the Tc-removal process on the actinides. Plutonium was also removed by the SnCl{sub 2} precipitation process. Results of this separation testing indicate that sorption/precipitation is a viable concept and has the potential to decontaminate the {sup 99}Tc from the stream, allowing it to be diverted away from WTP and thus eliminating the impact of the recycled halides and sulfate on the LAW glass volume. Based on the results, a possible treatment scenario could involve the use of a reductive precipitation agent (SnCl{sub 2}) with or without sorbent at neutral pH to remove the Tc. Although hydroxyapatite was not necessary to effect the {sup 99}Tc removal, it may be beneficial in solid-liquid separations. Other testing will examine removal of the other radionuclides. This testing was the second phase of testing, which aimed at optimizing the process by examining the minimum amount of reductant needed and the minimum reaction time. Although results indicated that SnCl{sub 2} was effective, further work on a pH-adjusted Fe(SO{sub 4}) mixture are needed. Additional tasks are needed to examine removal of the other radionuclides, solid-liquid separation technologies, slurry rheology measurements, composition variability impacts, corrosion and erosion, and slurry storage and immobilization.

  18. Acute ecotoxicology of natural oil and gas condensate to coral reef larvae.

    PubMed

    Negri, Andrew P; Brinkman, Diane L; Flores, Florita; Botté, Emmanuelle S; Jones, Ross J; Webster, Nicole S

    2016-01-01

    Risks posed by oil spills to coral reefs are difficult to evaluate, partially due to the absence of studies that adequately assess toxicity to relevant coral reef species. Here we experimentally tested the acute toxicity of condensate, representing a fraction of light crude oil, to coral (Acropora tenuis) and sponge (Rhopaloeides odorabile) larvae. The metamorphosis of coral larvae was inhibited at total petroleum aromatic hydrocarbon (TPAH) concentrations of water accommodated fractions (WAF) as low as 103 μg l(-1), similar to concentrations detected in seawater following large spills. The sensitivity of coral larvae increased by 40% when co-exposed to UV light that they might encounter in shallow reefal systems. Condensate WAF was more toxic to coral larvae than predicted by summing the toxicity of its main components (benzene, toluene, p-xylene and napthalene). In contrast, the sensitivity of sponge larvae to condensate WAF (>10,000 μg l(-1) TPAH) was far less than coral in the presence and absence of UV, but similar to that of other marine invertebrates. While these results highlight the relative sensitivity of coral larvae to oil, further research is needed to better understand and predict the impacts and risks posed by hydrocarbons to tropical reef systems. PMID:26892387

  19. Acute ecotoxicology of natural oil and gas condensate to coral reef larvae

    PubMed Central

    Negri, Andrew P.; Brinkman, Diane L.; Flores, Florita; Botté, Emmanuelle S.; Jones, Ross J.; Webster, Nicole S.

    2016-01-01

    Risks posed by oil spills to coral reefs are difficult to evaluate, partially due to the absence of studies that adequately assess toxicity to relevant coral reef species. Here we experimentally tested the acute toxicity of condensate, representing a fraction of light crude oil, to coral (Acropora tenuis) and sponge (Rhopaloeides odorabile) larvae. The metamorphosis of coral larvae was inhibited at total petroleum aromatic hydrocarbon (TPAH) concentrations of water accommodated fractions (WAF) as low as 103 μg l−1, similar to concentrations detected in seawater following large spills. The sensitivity of coral larvae increased by 40% when co-exposed to UV light that they might encounter in shallow reefal systems. Condensate WAF was more toxic to coral larvae than predicted by summing the toxicity of its main components (benzene, toluene, p-xylene and napthalene). In contrast, the sensitivity of sponge larvae to condensate WAF (>10,000 μg l−1 TPAH) was far less than coral in the presence and absence of UV, but similar to that of other marine invertebrates. While these results highlight the relative sensitivity of coral larvae to oil, further research is needed to better understand and predict the impacts and risks posed by hydrocarbons to tropical reef systems. PMID:26892387

  20. Rapid, conformal gas-phase formation of silica (SiO2) nanotubes from water condensates

    NASA Astrophysics Data System (ADS)

    Bae, Changdeuck; Kim, Hyunchul; Yang, Yunjeong; Yoo, Hyunjun; Montero Moreno, Josep M.; Bachmann, Julien; Nielsch, Kornelius; Shin, Hyunjung

    2013-06-01

    An innovative atomic layer deposition (ALD) concept, with which nanostructures of water condensates with high aspect ratio at equilibrium in cylindrical nanopores can be transformed uniformly into silica (SiO2) at near room temperature and ambient pressure, has been demonstrated for the first time. As a challenging model system, we first prove the conversion of cylindrical water condensates in porous alumina membranes to silica nanotubes (NTs) by introducing SiCl4 as a metal reactant without involving any catalytic reaction. Surprisingly, the water NTs reproducibly transformed into silica NTs, where the wall thickness of the silica NTs deposited per cycle was found to be limited by the amount of condensed water, and it was on the orders of ten nanometers per cycle (i.e., over 50 times faster than that of conventional ALD). More remarkably, the reactions only took place for 10-20 minutes or less without vacuum-related equipment. The thickness of initially adsorbed water layers in cylindrical nanopores was indirectly estimated from the thickness of formed SiO2 layers. With systematic experimental designs, we tackle the classical Kelvin equation in the nanosized pores, and the role of van der Waals forces in the nanoscale wetting phenomena, which is a long-standing issue lacking experimental insight. Moreover, we show that the present strategy is likely generalized to other oxide systems such as TiO2. Our approach opens up a new avenue for ultra-simple preparation of porous oxides and allows for the room temperature formation of dielectric layers toward organic electronic and photovoltaic applications.An innovative atomic layer deposition (ALD) concept, with which nanostructures of water condensates with high aspect ratio at equilibrium in cylindrical nanopores can be transformed uniformly into silica (SiO2) at near room temperature and ambient pressure, has been demonstrated for the first time. As a challenging model system, we first prove the conversion of cylindrical water condensates in porous alumina membranes to silica nanotubes (NTs) by introducing SiCl4 as a metal reactant without involving any catalytic reaction. Surprisingly, the water NTs reproducibly transformed into silica NTs, where the wall thickness of the silica NTs deposited per cycle was found to be limited by the amount of condensed water, and it was on the orders of ten nanometers per cycle (i.e., over 50 times faster than that of conventional ALD). More remarkably, the reactions only took place for 10-20 minutes or less without vacuum-related equipment. The thickness of initially adsorbed water layers in cylindrical nanopores was indirectly estimated from the thickness of formed SiO2 layers. With systematic experimental designs, we tackle the classical Kelvin equation in the nanosized pores, and the role of van der Waals forces in the nanoscale wetting phenomena, which is a long-standing issue lacking experimental insight. Moreover, we show that the present strategy is likely generalized to other oxide systems such as TiO2. Our approach opens up a new avenue for ultra-simple preparation of porous oxides and allows for the room temperature formation of dielectric layers toward organic electronic and photovoltaic applications. Electronic supplementary information (ESI) available: TEM gallery of silica NTs under different experimental conditions, detailed calculation of estimating the thickness of condensed water and Hamaker constants, and a comparison of processing times. See DOI: 10.1039/c3nr00906h

  1. Rapid, conformal gas-phase formation of silica (SiO2) nanotubes from water condensates.

    PubMed

    Bae, Changdeuck; Kim, Hyunchul; Yang, Yunjeong; Yoo, Hyunjun; Montero Moreno, Josep M; Bachmann, Julien; Nielsch, Kornelius; Shin, Hyunjung

    2013-07-01

    An innovative atomic layer deposition (ALD) concept, with which nanostructures of water condensates with high aspect ratio at equilibrium in cylindrical nanopores can be transformed uniformly into silica (SiO2) at near room temperature and ambient pressure, has been demonstrated for the first time. As a challenging model system, we first prove the conversion of cylindrical water condensates in porous alumina membranes to silica nanotubes (NTs) by introducing SiCl4 as a metal reactant without involving any catalytic reaction. Surprisingly, the water NTs reproducibly transformed into silica NTs, where the wall thickness of the silica NTs deposited per cycle was found to be limited by the amount of condensed water, and it was on the orders of ten nanometers per cycle (i.e., over 50 times faster than that of conventional ALD). More remarkably, the reactions only took place for 10-20 minutes or less without vacuum-related equipment. The thickness of initially adsorbed water layers in cylindrical nanopores was indirectly estimated from the thickness of formed SiO2 layers. With systematic experimental designs, we tackle the classical Kelvin equation in the nanosized pores, and the role of van der Waals forces in the nanoscale wetting phenomena, which is a long-standing issue lacking experimental insight. Moreover, we show that the present strategy is likely generalized to other oxide systems such as TiO2. Our approach opens up a new avenue for ultra-simple preparation of porous oxides and allows for the room temperature formation of dielectric layers toward organic electronic and photovoltaic applications. PMID:23695271

  2. Mass and Thermal Accommodation during Gas-Liquid Condensation of Water

    NASA Astrophysics Data System (ADS)

    Winkler, Paul M.; Vrtala, Aron; Wagner, Paul E.; Kulmala, Markku; Lehtinen, Kari E.; Vesala, Timo

    2004-08-01

    In this Letter we report, for the first time, direct and simultaneous determinations of mass and thermal accommodation coefficients for water vapor condensation in air, based on the observation of droplet growth kinetics in an expansion cloud chamber. Our experiments exclude values below 0.85 for the thermal and below 0.4 for the mass accommodation coefficients at temperatures ranging from 250 to 290K. Both coefficients are likely to be 1 for all studied conditions. Previously available experimental data on the mass accommodation coefficient for water span about 3orders of magnitude. Our results provide new and firm insight to cloud microphysics and consequently to the global radiative balance.

  3. Geological emission of methane from the Yakela condensed oil/gas field in Talimu Basin, Xinjiang, China.

    PubMed

    Tang, Junhong; Bao, Zhengyu; Xiang, Wu; Gou, Qinghong

    2008-01-01

    A static flux chamber method was applied to study natural emissions of methane into the atmosphere in the Yakela condensed oil/gas field in Talimu Basin, Xinjiang, China. Using an online method, which couples a gas chromatography/high-temperature conversion/isotope ratio mass spectrometry (GC/C/MS) together, the 13C/12C ratios of methane in the flux chambers were measured. The results demonstrated that methane gases were liable to migrate from deep oil/gas reservoir to the surface through microseepage and pervasion, and that a part of the migrated methane that remained unoxidized could emit into the atmosphere. Methane emission rates varied less in the oil/gas field because the whole region was homogeneous in geology and geography, with a standard deviation of less than 0.02 mg/(m2 x h). These were the differences in methane emission flux in the day and at night in the oil/gas field. The maximum methane emission flux reached 0.15 mg/(m2 x h) at 5:00-6:00 early in the morning, and then decreased gradually. The minimum was shown 0.10 mg/(m2 x h) at 17:00-18:00 in the afternoon, and then increased gradually. The daily methane released flux of the study area was 2.89 mg/(m2 x d), with a standard deviation of 0.43 mg/(m2 x d), using the average methane flux of every hour in a day for all chambers. delta13C of methane increased with the increase of methane concentration in the flux chambers, further indicating that the pyrogenetic origin of methane was come from deep oil/gas reservoirs. PMID:19143311

  4. Laboratory Optimization Tests of Technetium Decontamination of Hanford Waste Treatment Plant Direct Feed Low Activity Waste Melter Off-Gas Condensate Simulant

    SciTech Connect

    Taylor-Pashow, K.; McCabe, D.

    2015-12-23

    The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream (LAW Off-Gas Condensate) from the off-gas system. The baseline plan for disposition of this stream is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility. Alternate disposition of this stream would eliminate recycling of problematic components, and would enable less integrated operation of the LAW melter and the Pretreatment Facilities. Eliminating this stream from recycling within WTP would also decrease the LAW vitrification mission duration and quantity of glass waste.

  5. Molecular Bose-Einstein condensation in a Bose gas with a wide Feshbach resonance at finite temperatures

    SciTech Connect

    Yu Zengqiang; Yin Lan

    2010-02-15

    Bose-Einstein condensation (BEC) of Feshbach molecules in a homogeneous Bose gas is studied at finite temperatures in a single-channel mean-field approach where the Hartree-Fock energy and pairing gap are determined self-consistently. In the molecular-BEC state, the atomic excitation is gapped and the molecular excitation is gapless. The binding energy of Feshbach molecules is shifted from the vacuum value by many-body effects. When the scattering length a{sub s} of the atoms is negative, the system is subject to mechanical collapse due to negative compressibility. The system is stable in most regions with positive scattering lengths. However, at low temperatures near the resonance, the molecular-BEC state vanishes, and the coherent mixture of atomic and molecular BEC is subject to mechanical collapse.

  6. Development of turbine driven centrifugal compressors for non-condensible gas removal at geothermal power plants. Final report

    SciTech Connect

    1997-12-16

    Initial field tests have been completed for a Non-Condensible Gas (NCG) turbocompressor for geothermal power plants. It provides alternate technology to steam-jet ejectors and liquid-ring vacuum pumps that are currently used for NCG removal. It incorporates a number of innovative design features to enhance reliability, reduce steam consumption and reduce O&M costs. During initial field tests, the turbocompressor has been on-line for more than 4500 hours as a third stage compressor at The Geysers Unit 11 Power Plant. Test data indicates its overall efficiency is about 25% higher than a liquid-ring vacuum pump, and 250% higher than a steam-jet ejector when operating with compressor inlet pressures of 12.2 in-Hga and flow rates over 20,000 lbm/hr.

  7. Unusual well control techniques pay off. [Well drilling techniques in the Elgin gas condensate field, North Sea

    SciTech Connect

    Idelovici, J.L.

    1993-07-01

    Well control and completion operations were seriously complicated by an unusual pressure phenomena encountered while drilling an appraisal well through Jurassic sandstones in a high-pressure, high-temperature (HPHT), gas and condensate field located in the United Kingdom continental shelf. The HPHT sandstone reservoir is located in the Upper Jurassic Franklin formation. Unorthodox well-control techniques were used because it was determined that the abnormally high pressure was generated by a mechanical reaction of the rock under the effect of heavy mud and equivalent circulating density, rather than by entry into the wellbore of formation fluids. This paper reviews the complex drilling fluid control procedures which had to be utilized to maintain an open bore hole during drilling.

  8. Effect of scenedesmus acuminatus green algae extracts on the development of Candida lipolytic yeast in gas condensate-containing media

    NASA Technical Reports Server (NTRS)

    Bilmes, B. I.; Kasymova, G. A.; Runov, V. I.; Karavayeva, N. N.

    1980-01-01

    Data are given of a comparative study of the growth and development as well as the characteristics of the biomass of the C. Lipolytica yeast according to the content of raw protein, protein, lipids, vitamins in the B group, and residual hydrocarbons during growth in media with de-aromatized gas-condensate FNZ as the carbon source with aqueous and alcohol extracts of S. acuminatus as the biostimulants. It is shown that the decoction and aqueous extract of green algae has the most intensive stimulating effect on the yeast growth. When a decoction of algae is added to the medium, the content of residual hydrocarbons in the biomass of C. lipolytica yeast is reduced by 4%; the quantity of protein, lipids, thamine and inositol with replacement of the yeast autolysate by the decoction of algae is altered little.

  9. Mass and thermal accommodation during gas-liquid condensation of water.

    PubMed

    Winkler, Paul M; Vrtala, Aron; Wagner, Paul E; Kulmala, Markku; Lehtinen, Kari E J; Vesala, Timo

    2004-08-13

    In this Letter we report, for the first time, direct and simultaneous determinations of mass and thermal accommodation coefficients for water vapor condensation in air, based on the observation of droplet growth kinetics in an expansion cloud chamber. Our experiments exclude values below 0.85 for the thermal and below 0.4 for the mass accommodation coefficients at temperatures ranging from 250 to 290 K. Both coefficients are likely to be 1 for all studied conditions. Previously available experimental data on the mass accommodation coefficient for water span about 3 orders of magnitude. Our results provide new and firm insight to cloud microphysics and consequently to the global radiative balance. PMID:15324249

  10. Bénard instabilities in a binary-liquid layer evaporating into an inert gas: Stability of quasi-stationary and time-dependent reference profiles

    NASA Astrophysics Data System (ADS)

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

    2011-02-01

    This study treats an evaporating horizontal binary-liquid layer in contact with the air with an imposed transfer distance. The liquid is an aqueous solution of ethanol (10% wt). Due to evaporation, the ethanol mass fraction can change and a cooling occurs at the liquid-gas interface. This can trigger solutal and thermal Rayleigh-Bénard-Marangoni instabilities in the system, the modes of which corresponding to an undeformable interface form the subject of the present work. The decrease of the liquid-layer thickness is assumed to be slow on the diffusive time scales (quasi-stationarity). First we analyse the stability of quasi-stationary reference profiles for a model case within which the mass fraction of ethanol is assumed to be fixed at the bottom of the liquid. Then this consideration is generalized by letting the diffusive reference profile for the mass fraction in the liquid be transient (starting from a uniform state), while following the frozen-time approach for perturbations. The critical liquid thickness below which the system is stable at all times quite expectedly corresponds to the one obtained for the quasi-stationary profile. As a next step, a more realistic, zero-flux condition is used at the bottom in lieu of the fixed-concentration one. The critical thickness is found not to change much between these two cases. At larger thicknesses, the critical time at which the instability first appears proves, as can be expected, to be independent of the type of the concentration condition at the bottom. It is shown that solvent (water) evaporation plays a stabilizing role as compared to the case of a non-volatile solvent. At last, an effective approximate Pearson-like model is invoked making use in particular of the fact that the solutal Marangoni is by far the strongest as an instability mechanism here.

  11. METAL SPRAYER FOR USE IN VACUUM OR INERT ATMOSPHERE

    DOEpatents

    Monroe, R.E.

    1958-10-14

    A metal sprayer is described for use in a vacuum or inert atmosphere with a straight line wire feed and variable electrode contact angle. This apparatus comprises two wires which are fed through straight tubes of two mechanisms positioned on opposite sides of a central tube to which an inert gas is fed. The two mechanisms and the wires being fed constitute electrodes to which electrical current is supplied so that the wires are melted by the electric are formed at their contacting region and sprayed by the gas supplied by the central tube. This apparatus is designed specifically to apply a zirconium coating to uranium in an inert atmosphere and without the use of an oxidizing flame.

  12. Applications of UT results to confirm defects findings by utilization of relevant metallurgical investigations techniques on gas/condensate pipeline working in wet sour gas environment

    NASA Astrophysics Data System (ADS)

    El-Azhari, O. A.; Gajam, S. Y.

    2015-03-01

    The gas/condensate pipe line under investigation is a 12 inch diameter, 48 km ASTM, A106 steel pipeline, carrying hydrocarbons containing wet CO2 and H2S.The pipe line had exploded in a region 100m distance from its terminal; after 24 years of service. Hydrogen induced cracking (HIC) and sour gas corrosion were expected due to the presence of wet H2S in the gas analysis. In other areas of pipe line ultrasonic testing was performed to determine whether the pipeline can be re-operated. The results have shown presence of internal planner defects, this was attributed to the existence of either laminations, type II inclusions or some service defects such as HIC and step wise cracking (SWC).Metallurgical investigations were conducted on fractured samples as per NACE standard (TM-0284-84). The obtained results had shown macroscopic cracks in the form of SWC, microstructure of steel had MnS inclusions. Crack sensitivity analyses were calculated and the microhardness testing was conducted. These results had confirmed that the line material was suffering from sour gas deteriorations. This paper correlates the field UT inspection findings with those methods investigated in the laboratory. Based on the results obtained a new HIC resistance material pipeline needs to be selected.

  13. -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.

  14. Dynamics and Evolution of SO2 Gas Condensation Around Prometheus-like Volcanic Plumes on Io as Seen by the Near Infrared Mapping Spectrometer

    NASA Technical Reports Server (NTRS)

    Doute, S.; Lopes-Gautier, R.; Smythe, W. D.; Kamp, L. W.; Carlson, R.

    2001-01-01

    Near Infrared Mapping Spectrometer data acquired during the I24, 25, and 27 Io's Fly-bys by Galileo are analyzed to map the SO2 frost abundance and granularity. This allows a better understanding of the dynamics and evolution of gas condensation around volcanic plumes. Additional information is contained in the original extended abstract.

  15. AN INNOVATIVE TRANSPORT MEMBRANE CONDENSER FOR WATER RECOVERY FROM GAS AND ITS REUSE - PHASE I

    EPA Science Inventory

    Although water recycle and reuse is considered good environmental practice, its implementation is highly dependent on the economics and hence can be challenging to implement. In this project, we present a unique opportunity to recover both water and energy from boiler flue gas...

  16. Synthesis and morphology of iron-iron oxide core-shell nanoparticles produced by high pressure gas condensation.

    PubMed

    Xing, Lijuan; Ten Brink, Gert H; Chen, Bin; Schmidt, Franz P; Haberfehlner, Georg; Hofer, Ferdinand; Kooi, Bart J; Palasantzas, George

    2016-05-27

    Core-shell structured Fe nanoparticles (NPs) produced by high pressure magnetron sputtering gas condensation were studied using transmission electron microscopy (TEM) techniques, electron diffraction, electron energy-loss spectroscopy (EELS), tomographic reconstruction, and Wulff shape construction analysis. The core-shell structure, which is composed of an Fe core surrounded by a maghemite (γ-Fe2O3) and/or magnetite (Fe3O4) shell, was confirmed by fast Fourier transform (FFT) analysis combined with EELS. It was found that the particle size and shape strongly depend on the gas environment. Moreover, extensive analysis showed that NPs with a size between 10-20 nm possess a truncated cubic morphology, which is confined by the 6 {100} planes that are truncated by the 12 {110} planes at different degrees. For NPs larger than 20 nm, the rhombic dodecahedron defined by the 12 {110} planes is the predominant crystal shape, while truncated rhombic dodecahedrons, as well as non-truncated and truncated cubic NPs, were also observed. The NPs without truncation showed a characteristic inward relaxation indicating that besides thermodynamics kinetics also plays a crucial role during particle growth. PMID:27089553

  17. Synthesis and morphology of iron–iron oxide core–shell nanoparticles produced by high pressure gas condensation

    NASA Astrophysics Data System (ADS)

    Xing, Lijuan; ten Brink, Gert H.; Chen, Bin; Schmidt, Franz P.; Haberfehlner, Georg; Hofer, Ferdinand; Kooi, Bart J.; Palasantzas, George

    2016-05-01

    Core–shell structured Fe nanoparticles (NPs) produced by high pressure magnetron sputtering gas condensation were studied using transmission electron microscopy (TEM) techniques, electron diffraction, electron energy-loss spectroscopy (EELS), tomographic reconstruction, and Wulff shape construction analysis. The core–shell structure, which is composed of an Fe core surrounded by a maghemite (γ-Fe2O3) and/or magnetite (Fe3O4) shell, was confirmed by fast Fourier transform (FFT) analysis combined with EELS. It was found that the particle size and shape strongly depend on the gas environment. Moreover, extensive analysis showed that NPs with a size between 10–20 nm possess a truncated cubic morphology, which is confined by the 6 {100} planes that are truncated by the 12 {110} planes at different degrees. For NPs larger than 20 nm, the rhombic dodecahedron defined by the 12 {110} planes is the predominant crystal shape, while truncated rhombic dodecahedrons, as well as non-truncated and truncated cubic NPs, were also observed. The NPs without truncation showed a characteristic inward relaxation indicating that besides thermodynamics kinetics also plays a crucial role during particle growth.

  18. A Lagrangian-Eulerian approach to modeling homogeneous condensation in high density gas expansions.

    PubMed

    Jansen, Ryan; Gimelshein, Natalia; Gimelshein, Sergey; Wysong, Ingrid

    2011-03-14

    A computational approach to homogeneous nucleation is proposed based on Eulerian description of the gas phase expansion coupled with a Lagrangian approach to the cluster formation. A continuum, Euler/Navier-Stokes solver versatile advection code is used to model the gas transport, and a kinetic particle solver is developed in this work to simulate cluster nucleation and growth. Parameters in the new model were adjusted so as to match the known theoretical dimer formation equilibrium constants for the two gases under consideration, argon and water. Reasonable agreement between computed and available experimental data was found in terminal cluster size distributions for nozzle water expansions in a wide range of stagnation pressures. The proposed approach was found to be orders of magnitude faster than a comparable approach based on the direct simulation Monte Carlo method. PMID:21405154

  19. Inert wastes -- A live issue

    SciTech Connect

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

    1996-12-31

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

  20. A compact setup to study homogeneous nucleation and condensation.

    PubMed

    Karlsson, Mattias; Alxneit, Ivo; Rtten, Frederik; Wuillemin, Daniel; Tschudi, Hans Rudolf

    2007-03-01

    An experiment is presented to study homogeneous nucleation and the subsequent droplet growth at high temperatures and high pressures in a compact setup that does not use moving parts. Nucleation and condensation are induced in an adiabatic, stationary expansion of the vapor and an inert carrier gas through a Laval nozzle. The adiabatic expansion is driven against atmospheric pressure by pressurized inert gas its mass flow carefully controlled. This allows us to avoid large pumps or vacuum storage tanks. Because we eventually want to study the homogeneous nucleation and condensation of zinc, the use of carefully chosen materials is required that can withstand pressures of up to 10(6) Pa resulting from mass flow rates of up to 600 l(N) min(-1) and temperatures up to 1200 K in the presence of highly corrosive zinc vapor. To observe the formation of droplets a laser beam propagates along the axis of the nozzle and the light scattered by the droplets is detected perpendicularly to the nozzle axis. An ICCD camera allows to record the scattered light through fused silica windows in the diverging part of the nozzle spatially resolved and to detect nucleation and condensation coherently in a single exposure. For the data analysis, a model is needed to describe the isentropic core part of the flow along the nozzle axis. The model must incorporate the laws of fluid dynamics, the nucleation and condensation process, and has to predict the size distribution of the particles created (PSD) at every position along the nozzle axis. Assuming Rayleigh scattering, the intensity of the scattered light can then be calculated from the second moment of the PSD. PMID:17411197

  1. Stardust: Studies in microgravity of condensation and agglomeration of cosmic dust analogue

    NASA Technical Reports Server (NTRS)

    Ferguson, F.; Lilleleht, L. U.; Nuth, J.; Stephens, J. R.; Bussoletti, E.; Carotenuto, L.; Colangeli, L.; Dellaversana, P.; Mele, F.; Mennella, V.

    1992-01-01

    A short description of the program Stardust whose goal is to study the formation and properties of high temperature particles and gases, including silicate and carbonaceous materials, that are of interest in astrophysics and planetary science, is given. The international program was carried out in microgravity conditions in parabolic flight. A description of the laboratory equipment, conceived to perform experimental tests in reduced gravity conditions, and which is based on the gas evaporation technique, is given. The gas evaporation technique utilizes one or more heated crucible to vaporize solids materials (SiO, Mg) in a low pressure of inert or reactive gas inside of a vacuum bell jar. The vapor pressures of the materials are controlled by the temperature of the crucibles. The temperature and pressure of inert gas are also controlled. By varying the vapor pressure relative to the gas temperature and pressure, the conditions for substantial grain condensation can be controlled and grain formation measured using light scattering techniques. Thus the partial pressure for grain condensation, can be measured as a function of temperature. The gas evaporation technique has the advantage that complex chemical systems can be studied by using multiple crucibles each containing solid source material. Experimental results and future trends are addressed.

  2. Stardust: Studies in microgravity of condensation and agglomeration of cosmic dust analogue

    NASA Astrophysics Data System (ADS)

    Ferguson, F.; Lilleleht, L. U.; Nuth, J.; Stephens, J. R.; Bussoletti, E.; Carotenuto, L.; Colangeli, L.; Dellaversana, P.; Mele, F.; Mennella, V.

    1992-07-01

    A short description of the program Stardust whose goal is to study the formation and properties of high temperature particles and gases, including silicate and carbonaceous materials, that are of interest in astrophysics and planetary science, is given. The international program was carried out in microgravity conditions in parabolic flight. A description of the laboratory equipment, conceived to perform experimental tests in reduced gravity conditions, and which is based on the gas evaporation technique, is given. The gas evaporation technique utilizes one or more heated crucible to vaporize solids materials (SiO, Mg) in a low pressure of inert or reactive gas inside of a vacuum bell jar. The vapor pressures of the materials are controlled by the temperature of the crucibles. The temperature and pressure of inert gas are also controlled. By varying the vapor pressure relative to the gas temperature and pressure, the conditions for substantial grain condensation can be controlled and grain formation measured using light scattering techniques. Thus the partial pressure for grain condensation, can be measured as a function of temperature. The gas evaporation technique has the advantage that complex chemical systems can be studied by using multiple crucibles each containing solid source material. Experimental results and future trends are addressed.

  3. Inert anodes for aluminum smelting

    SciTech Connect

    Weyand, J.D.; Ray, S.P.; Baker, F.W.; DeYoung, D.H.; Tarcy, G.P.

    1986-02-01

    The use of nonconsumable or inert anodes for replacement of consumable carbon anodes in Hall electrolysis cells for the production of aluminum has been a technical and commercial goal of the aluminum industry for many decades. This report summarizes the technical success realized in the development of an inert anode that can be used to produce aluminum of acceptable metal purity in small scale Hall electrolysis cells. The inert anode material developed consists of a cermet composition containing the phases: copper, nickel ferrite and nickel oxide. This anode material has an electrical conductivity comparable to anode carbon used in Hall cells, i.e., 150 ohm {sup {minus}1}cm{sup {minus}1}. Metal purity of 99.5 percent aluminum has been produced using this material. The copper metal alloy present in the anode is not removed by anodic dissolution as does occur with cermet anodes containing a metallic nickel alloy. Solubility of the oxide phases in the cryolite electrolyte is reduced by: (1) saturated concentration of alumina, (2) high nickel oxide content in the NiO-NiFe{sub 2}O{sub 4} composition, (3) lowest possible cell operating temperature, (4) additions of alkaline or alkaline earth fluorides to the bath to reduce solubilities of the anode components, and (5) avoiding bath contaminants such as silica. Dissolution rate measurements indicate first-order kinetics and that the rate limiting step for dissolution is mass transport controlled. 105 refs., 234 figs., 73 tabs.

  4. Developing a scalable inert gas ion thruster

    NASA Technical Reports Server (NTRS)

    James, E.; Ramsey, W.; Steiner, G.

    1982-01-01

    Analytical studies to identify and then design a high performance scalable ion thruster operating with either argon or xenon for use in large space systems are presented. The magnetoelectrostatic containment concept is selected for its efficient ion generation capabilities. The iterative nature of the bounding magnetic fields allows the designer to scale both the diameter and length, so that the thruster can be adapted to spacecraft growth over time. Three different thruster assemblies (conical, hexagonal and hemispherical) are evaluated for a 12 cm diameter thruster and performance mapping of the various thruster configurations shows that conical discharge chambers produce the most efficient discharge operation, achieving argon efficiencies of 50-80% mass utilization at 240-310 eV/ion and xenon efficiencies of 60-97% at 240-280 eV/ion. Preliminary testing of the large 30 cm thruster, using argon propellant, indicates a 35% improvement over the 12 cm thruster in mass utilization efficiency. Since initial performance is found to be better than projected, a larger 50 cm thruster is already in the development stage.

  5. 7 CFR 201.19 - Inert matter.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

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

  6. 7 CFR 201.19 - Inert matter.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

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

  7. 7 CFR 201.19 - Inert matter.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Inert matter. 201.19 Section 201.19 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.19 Inert matter. The label shall show the percentage by weight of inert matter....

  8. Measurement of reactive and condensable gas permeation using a mass spectrometer

    SciTech Connect

    Zhang Xiaodong; Lewis, Jay S.; Parker, Charles B.; Glass, Jeffrey T.; Wolter, Scott D.

    2008-09-15

    Permeation of water vapor, oxygen, nitrogen, and carbon dioxide through polymer films is measured by the programed valving mass spectrometry (PVMS) method. The results are calibrated with a standard permeation rate for each gas to determine the detection sensitivity. The calibrated lower detection limits are 1.90x10{sup -7} g/m{sup 2} day for water vapor, 2.81x10{sup -2} cm{sup 3}/m{sup 2} day for oxygen, 2.15x10{sup -2} cm{sup 3}/m{sup 2} day for nitrogen, and 3.29x10{sup -2} cm{sup 3}/m{sup 2} day for carbon dioxide. The lower detection limits presented here for water vapor, nitrogen, and carbon dioxide are more than two orders of magnitude lower than the corresponding values offered by the NIST-traceable standard techniques. In addition, the PVMS water vapor lower detection limit meets the sensitivity requirement for detecting 'ultrabarrier' water vapor permeation rates, while the oxygen lower detection limit is higher than that offered by the standard technique. However, the results suggest a modified measurement protocol and/or system modifications to overcome this limitation. Effusivity through a flow orifice was also examined using the PVMS method for the above gases. The effusion results from the flow orifice, combined with the permeation results from polymer samples, provide insight into the factors that may influence gas detection sensitivities.

  9. Product characteristics from the torrefaction of oil palm fiber pellets in inert and oxidative atmospheres.

    PubMed

    Chen, Wei-Hsin; Zhuang, Yi-Qing; Liu, Shih-Hsien; Juang, Tarng-Tzuen; Tsai, Chi-Ming

    2016-01-01

    The aim of this work was to study the characteristics of solid and liquid products from the torrefaction of oil palm fiber pellets (OPFP) in inert and oxidative environments. The torrefaction temperature and O2 concentration in the carrier gas were in the ranges of 275-350°C and 0-10 vol%, respectively, while the torrefaction duration was 30 min. The oxidative torrefaction of OPFP at 275°C drastically intensified the HHV of the biomass when compared to the non-oxidative torrefaction. OPFP torrefied at 300°C is recommended to upgrade the biomass, irrespective of the atmosphere. The HHV of condensed liquid was between 10.1 and 13.2 MJ kg(-)(1), and was promoted to 23.2-28.7 MJ kg(-)(1) following dewatering. This accounts for 92-139% improvement in the calorific value of the liquid. This reveals that the recovery of condensed liquid with dewatering is able to enhance the energy efficiency of a torrefaction system. PMID:26346262

  10. Macromolecular ensembles of cyclodextrin crystallohydrates and clathrates--experimental and theoretical gas--and condense phase study.

    PubMed

    Ivanova, Bojidarka; Spiteller, Michael

    2014-03-01

    The paper reported a joined mass spectrometric, crystallographic and quantum chemical study of crystallohydrates, emphasizing on clathrates of native α-, and β-cyclodextrins as well as their randomly acetylated derivatives (4 and 5). The physical data are compared with 19 crystals of CDs, three of which new ones, differed by number of crystallohydrate (and/or clathrate) molecules (n)). The macroscopic complex CDs/n stability (n∈ [0.60-12.26]) is evaluated theoretically, accounting the surface and clathrate self-assembly of non-covalent hydrogen bonding interactions. The variety of competitive condensation processes of randomly acetylated products and the non-specific phase transition adduct of CDs and aggregates, which complicated significantly the MS picture are discussed. The single crystal X-ray diffraction, enable to determine the non-covalent interactions in CDs crystals, which physical phenomena in the gas-phase and crystalline phase → liquid phase → GP and CP → GP transitions are evidenced mass spectrometrically. The quantum chemical method provided important thermodynamics and structural information at variety of states, allowing understanding comprehensively the complex GP phenomena. Special emphasis in the paper content is dedicated to the phenomenology of the GP mass spectrometric ionization processes and thermodynamics of fragmentation molecular ions of CDs and their supramolecular self-assembly which, strongly depends on the experimental factors. PMID:24370472

  11. Method and apparatus for maintaining condensable constituents of a gas in a vapor phase during sample transport

    DOEpatents

    Felix, Larry Gordon; Farthing, William Earl; Irvin, James Hodges; Snyder, Todd Robert

    2010-05-18

    A system for fluid transport at elevated temperatures having a conduit having a fluid inlet end and a fluid outlet end and at least one heating element disposed within the conduit providing direct heating of a fluid flowing through the conduit. The system is particularly suited for preventing condensable constituents of a high temperature fluid from condensing out of the fluid prior to analysis of the fluid. In addition, operation of the system so as to prevent the condensable constituents from condensing out of the fluid surprisingly does not alter the composition of the fluid.

  12. Inert doublet model and LEP II limits

    SciTech Connect

    Lundstroem, Erik; Gustafsson, Michael; Edsjoe, Joakim

    2009-02-01

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

  13. Kinetics and energy states of nanoclusters in the initial stage of homogeneous condensation at high supersaturation degrees

    SciTech Connect

    Vorontsov, A. G.; Gel'chinskii, B. R.; Korenchenko, A. E.

    2012-11-15

    The condensation of metal vapor in an inert gas is studied by the molecular dynamics method. Two condensation regimes are investigated: with maintenance of partial pressure of the metal vapor and with a fixed number of metal atoms in the system. The main focus is the study of the cluster energy distribution over the degrees of freedom and mechanisms of the establishment of thermal equilibrium. It is shown that the internal temperature of a cluster considerably exceeds the buffer gas temperature and the thermal balance is established for a time considerably exceeding the nucleation time. It is found that, when the metal vapor concentration exceeds 0.1 of the argon concentration, the growth of clusters with the highest possible internal energy occurs, the condensation rate being determined only by the rate of heat removal from clusters.

  14. Broad iron emission lines in Seyfert galaxies - re-condensation of gas onto an inner disk below the ADAF?

    NASA Astrophysics Data System (ADS)

    Meyer-Hofmeister, E.; Meyer, F.

    2011-03-01

    Context. The number of strong iron Kα line detections in Seyfert AGN is clearly growing in the Chandra, XMM-Newton and Suzaku era. The iron emission lines are broad, some are relativistically blurred. These relativistic disk lines have also been observed for galactic black hole X-ray binaries. Thermal components found in hard spectra were interpreted as an indication for a weak inner cool accretion disk underneath a hot corona. Aims: Accretion in low-mass X-ray binaries (LMXB) occurs during phases of high and low mass accretion rate, outburst and quiescence, soft and hard spectral state, respectively. After the soft/hard transition for some sources a thermal component is found, which can be interpreted as sustained by re-condensation of gas from an advection-dominated flow (ADAF) onto the disk. In view of the similarity of accretion flows around stellar mass and supermassive black holes we discuss whether the broad iron emission lines in Seyfert 1 AGN (active galactic nuclei) can be understood as arising from a similar accretion flow geometry as in X-ray binaries. Methods: We derive accretion rates for those Seyfert galaxies for which broad iron emission lines were observed, the "best candidates" in the investigations of Miller (2007, ARA&A, 45, 441) and Nandra et al. (2007, MNRAS, 382, 194). For the evaluation of the Eddington-scaled rates we use the observed X-ray luminosity, bolometric corrections and black hole masses from the literature. Results: The accretion rates derived for the Seyfert galaxies in our sample are less than 0.1 of the Eddington rate for more than half of the sources. For 107 to 108M⊙ black holes in Seyfert 1 AGN this limit corresponds to 0.01 to 0.2 M⊙/yr. This documents that the sources probably are in a hard spectral state and iron emission lines can arise from an inner weak accretion disk surrounded by an ADAF as predicted by the re-condensation model. Some of the remaining sources with higher accretion rates may be in a spectral state that is comparable to the "very high" state of LMXBs. Conclusions: Our investigation shows that in quite a number of Seyfert AGN the broad iron emission lines may indeed originate in a weak inner disk below the ADAF, close to the black hole, indicating the same accretion flow geometry as recently found for LMXBs. For the accretion history one then concludes that the accretion rates were higher in the outer radii at some earlier time.

  15. Measurements of gas sorption from seawater and the influence of gas release on open-cycle ocean thermal energy conversion (OC-OTEC) system performance

    SciTech Connect

    Penney, T.R.; Althof, J.A.

    1985-06-01

    The technical community has questioned the validity and cost-effectiveness of open-cycle ocean thermal energy conversion (OC-OTEC) systems because of the unknown effect of noncondensable gas on heat exchanger performance and the power needed to run vacuum equipment to remove this gas. To date, studies of seawater gas desorption have not been prototypical for system level analysis. This study gives preliminary gas desorption data on a vertical spout, direct contact evaporator and multiple condenser geometries. Results indicate that dissolved gas can be substantially removed before the seawater enters the heat exchange process, reducing the uncertainty and effect of inert gas on heat exchanger performance.

  16. Inert gases in a terra sample - Measurements in six grain-size fractions and two single particles from Lunar 20.

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

    Review of the results of inert gas measurements performed on six grain-size fractions and two single particles from four samples of Luna 20 material. Presented and discussed data include the inert gas contents, element and isotope systematics, radiation ages, and Ar-36/Ar-40 systematics.

  17. [On-line method for measurement of the carbon isotope ratio of atmospheric methane and its application to atmosphere of Yakela condensed gas field].

    PubMed

    Tang, Jun-Hong; Bao, Zheng-Yu; Xiang, Wu; Qiao, Sheng-Ying; Li, Bing

    2006-01-01

    An on-line method for measurement of the 13C/12C ratio of methane by a gas chromatography/high-temperature conversion/ isotope ratio mass spectrometry (GC/C/MS) technique was developed. This method is less laborious, more rapid (45 min), of high precision (+/- 0.4 x 10(-3)) and by using a small amount of sample (about 200 mL of atmosphere). Its application to isotopic characterization, and hence methane source identification, was demonstrated by examination of atmosphere sample collected in Yakela condensed gas field, China. The average 13C/12C ratio of atmospheric methane in Yakela field was -45.0 x 10(-3) heavier by 1.2 x 10(-3) -2.0 x 10(-3) than the global average. This is caused by seepage and diffusing of methane from Yakela condensed gas reservoir. The concentrations of atmospheric methane in daytimes are found to be lower than those in nighttimes, and the corresponding 13C/12C ratios in daytimes are lighter compared to those in nighttimes, a phenomena probably caused by the fact that a small part of methane from Yakela condensate reservoir is consumed in soil's surface under sunlight. PMID:16599113

  18. Method for removing metal vapor from gas streams

    DOEpatents

    Ahluwalia, R.K.; Im, K.H.

    1996-04-02

    A process for cleaning an inert gas contaminated with a metallic vapor, such as cadmium, involves withdrawing gas containing the metallic contaminant from a gas atmosphere of high purity argon; passing the gas containing the metallic contaminant to a mass transfer unit having a plurality of hot gas channels separated by a plurality of coolant gas channels; cooling the contaminated gas as it flows upward through the mass transfer unit to cause contaminated gas vapor to condense on the gas channel walls; regenerating the gas channels of the mass transfer unit; and, returning the cleaned gas to the gas atmosphere of high purity argon. The condensing of the contaminant-containing vapor occurs while suppressing contaminant particulate formation, and is promoted by providing a sufficient amount of surface area in the mass transfer unit to cause the vapor to condense and relieve supersaturation buildup such that contaminant particulates are not formed. Condensation of the contaminant is prevented on supply and return lines in which the contaminant containing gas is withdrawn and returned from and to the electrorefiner and mass transfer unit by heating and insulating the supply and return lines. 13 figs.

  19. Method for removing metal vapor from gas streams

    DOEpatents

    Ahluwalia, R. K.; Im, K. H.

    1996-01-01

    A process for cleaning an inert gas contaminated with a metallic vapor, such as cadmium, involves withdrawing gas containing the metallic contaminant from a gas atmosphere of high purity argon; passing the gas containing the metallic contaminant to a mass transfer unit having a plurality of hot gas channels separated by a plurality of coolant gas channels; cooling the contaminated gas as it flows upward through the mass transfer unit to cause contaminated gas vapor to condense on the gas channel walls; regenerating the gas channels of the mass transfer unit; and, returning the cleaned gas to the gas atmosphere of high purity argon. The condensing of the contaminant-containing vapor occurs while suppressing contaminant particulate formation, and is promoted by providing a sufficient amount of surface area in the mass transfer unit to cause the vapor to condense and relieve supersaturation buildup such that contaminant particulates are not formed. Condensation of the contaminant is prevented on supply and return lines in which the contaminant containing gas is withdrawn and returned from and to the electrorefiner and mass transfer unit by heating and insulating the supply and return lines.

  20. Design of a high temperature chemical vapor deposition reactor in which the effect of the condensation of exhaust gas in the outlet is minimized using computational modeling

    NASA Astrophysics Data System (ADS)

    Yoon, Ji-Young; Geun Kim, Byeong; Nam, Deok-Hui; Yoo, Chang-Hyoung; Lee, Myung-Hyun; Seo, Won-Seon; Shul, Yong-Gun; Lee, Won-Jae; Jeong, Seong-Min

    2016-02-01

    Tetramethylsilane (TMS) was recently proposed as a safe precursor for SiC single crystal growth through high temperature chemical vapor deposition (HTCVD). Because the C content of TMS is much higher than Si, the exhaust gas from the TMS-based HTCVD contains large amounts of C which is condensed in the outlet. Because the condensed C close to the crystal growth front will influence on the thermodynamic equilibrium in the crystal growth, an optimal reactor design was highly required to exclude the effect of the condensed carbon. In this study, we report on a mass/heat transfer analysis using the finite element method (FEM) in an attempt to design an effective reactor that will minimize the effect of carbon condensation in the outlet. By applying the proposed reactor design to actual growth experiments, single 6H-SiC crystals with diameters of 50 mm were successfully grown from a 6H-SiC seed. This result confirms that the proposed reactor design can be used to effectively grow 6H-SiC crystals using TMS-based HTCVD.

  1. Kinetic boundary layers in gas mixtures: Systems described by nonlinearly coupled kinetic and hydrodynamic equations and applications to droplet condensation and evaporation

    SciTech Connect

    Widder, M.E.; Titulaer, U.M. )

    1993-03-01

    The authors consider a mixture of heavy vapor molecules and a light carrier gas surrounding a liquid droplet. The vapor is described by a variant of the Klein-Kramers equation; the gas is described by the Navier-Stokes equations; the droplet acts as a heat source due to the released heat of condensation. The exchange of momentum and energy between the constituents of the mixture is taken into account by force terms in the kinetic equation and source terms in the Navier-Stokes equations. These are chosen to obtain maximal agreement with the irreversible thermodynamics of a gas mixture. The structure of the kinetic boundary layer around the sphere is determined from the self-consistent solution of this set of coupled equations with appropriate boundary conditions at the surface of the sphere. The kinetic equation is rewritten as a set of coupled moment equations. A complete set of solutions of these moment equations is constructed by numerical integration inward from the region far away from the droplet, where the background inhomogeneities are small. A technique developed earlier is used to deal with the numerical instability of the moment equations. The solutions obtained for given temperature and pressure profiles in the gas are then combined linearly such that they obey the boundary conditions at the droplet surface; from this solution source terms for the Navier-Stokes equation of the gas are constructed and used to determine improved temperature and pressure profiles for the background gas. For not too large temperature differneces between the droplet and the gas at infinity, self-consistency is reached after a few iterations. The method is applied to the condensation of droplets from a supersaturated vapor as well as to strong evaporation of droplets under the influence of an external heat source, where corrections of up to 40% are obtained.

  2. Non-equilibrium Properties of a Pumped-Decaying Bose-Condensed Electron-Hole Gas in the BCS-BEC Crossover Region

    NASA Astrophysics Data System (ADS)

    Hanai, R.; Littlewood, P. B.; Ohashi, Y.

    2016-03-01

    We theoretically investigate a Bose-condensed exciton gas out of equilibrium. Within the framework of the combined BCS-Leggett strong-coupling theory with the non-equilibrium Keldysh formalism, we show how the Bose-Einstein condensation (BEC) of excitons is suppressed to eventually disappear, when the system is in the non-equilibrium steady state. The supply of electrons and holes from the bath is shown to induce quasi-particle excitations, leading to the partial occupation of the upper branch of Bogoliubov single-particle excitation spectrum. We also discuss how this quasi-particle induction is related to the suppression of exciton BEC, as well as the stability of the steady state.

  3. Identification of polar organic compounds in coal-gasification condensate water by gas chromatography-mass spectrometry analysis of high-performance liquid chromatography fractions

    SciTech Connect

    Mohr, D.H.; King, C.J.

    1985-10-01

    A novel combination of analytical techniques was employed to identify polar organic compounds, including the first report of hydantoins, in condensate waters from a slagging fixed-bed coal-gasification process. The analytical technique consists of high-performance liquid chromatography (HPLC) separation and gas chromatography-mass spectrometry (GC-MS) analysis of HPLC fractions. Entrainer distillation was used to concentrate the HPLC fractions and remove water before GC-MS analysis. Analyses of four samples accounted for 69-84% of the measured chemical oxygen demand (COD), including 1-6% of the COD as dimethylhydantoin. This compound is highly polar and difficult to remove by solvent extraction. Other identified compounds included phenols, di-hydroxybenzenes, methanol, acetone, and acetonitrile. Many of the unidentified compounds (16-31% of the COD) were difficult to extract, had low volatility relative to water, and contained organic nitrogen. Some chemical changes were observed during storage of condensate water samples.

  4. Non-equilibrium Properties of a Pumped-Decaying Bose-Condensed Electron-Hole Gas in the BCS-BEC Crossover Region

    NASA Astrophysics Data System (ADS)

    Hanai, R.; Littlewood, P. B.; Ohashi, Y.

    2016-05-01

    We theoretically investigate a Bose-condensed exciton gas out of equilibrium. Within the framework of the combined BCS-Leggett strong-coupling theory with the non-equilibrium Keldysh formalism, we show how the Bose-Einstein condensation (BEC) of excitons is suppressed to eventually disappear, when the system is in the non-equilibrium steady state. The supply of electrons and holes from the bath is shown to induce quasi-particle excitations, leading to the partial occupation of the upper branch of Bogoliubov single-particle excitation spectrum. We also discuss how this quasi-particle induction is related to the suppression of exciton BEC, as well as the stability of the steady state.

  5. Kinetic multi-layer model of gas-particle interactions in aerosols and clouds (KM-GAP): linking condensation, evaporation and chemical reactions of organics, oxidants and water

    NASA Astrophysics Data System (ADS)

    Shiraiwa, M.; Pfrang, C.; Koop, T.; Pschl, U.

    2011-12-01

    We present a novel kinetic multi-layer model for gas-particle interactions in aerosols and clouds (KM-GAP) that treats explicitly all steps of mass transport and chemical reaction of semi-volatile species partitioning between gas phase, particle surface and particle bulk. KM-GAP is based on the PRA model framework (Pschl-Rudich-Ammann, 2007), and it includes gas phase diffusion, reversible adsorption, surface reactions, bulk diffusion and reaction, as well as condensation, evaporation and heat transfer. The size change of atmospheric particles and the temporal evolution and spatial profile of the concentration of individual chemical species can be modeled along with gas uptake and accommodation coefficients. Depending on the complexity of the investigated system, unlimited numbers of semi-volatile species, chemical reactions, and physical processes can be treated, and the model shall help to bridge gaps in the understanding and quantification of multiphase chemistry and microphysics in atmospheric aerosols and clouds. In this study we demonstrate how KM-GAP can be used to analyze, interpret and design experimental investigations of changes in particle size and chemical composition in response to condensation, evaporation, and chemical reaction. For the condensational growth of water droplets, our kinetic model results provide a direct link between laboratory observations and molecular dynamic simulations, confirming that the accommodation coefficient of water at ~270 K is close to unity. Literature data on the evaporation of dioctyl phthalate as a function of particle size and time can be reproduced, and the model results suggest that changes in the experimental conditions like aerosol particle concentration and chamber geometry may influence the evaporation kinetics and can be optimized for efficient probing of specific physical effects and parameters. With regard to oxidative aging of organic aerosol particles, we illustrate how the formation and evaporation of volatile reaction products like nonanal can cause a decrease in the size of oleic acid particles exposed to ozone.

  6. Kinetic multi-layer model of gas-particle interactions in aerosols and clouds (KM-GAP): linking condensation, evaporation and chemical reactions of organics, oxidants and water

    NASA Astrophysics Data System (ADS)

    Shiraiwa, M.; Pfrang, C.; Koop, T.; Pöschl, U.

    2012-03-01

    We present a novel kinetic multi-layer model for gas-particle interactions in aerosols and clouds (KM-GAP) that treats explicitly all steps of mass transport and chemical reaction of semi-volatile species partitioning between gas phase, particle surface and particle bulk. KM-GAP is based on the PRA model framework (Pöschl-Rudich-Ammann, 2007), and it includes gas phase diffusion, reversible adsorption, surface reactions, bulk diffusion and reaction, as well as condensation, evaporation and heat transfer. The size change of atmospheric particles and the temporal evolution and spatial profile of the concentration of individual chemical species can be modeled along with gas uptake and accommodation coefficients. Depending on the complexity of the investigated system and the computational constraints, unlimited numbers of semi-volatile species, chemical reactions, and physical processes can be treated, and the model shall help to bridge gaps in the understanding and quantification of multiphase chemistry and microphysics in atmospheric aerosols and clouds. In this study we demonstrate how KM-GAP can be used to analyze, interpret and design experimental investigations of changes in particle size and chemical composition in response to condensation, evaporation, and chemical reaction. For the condensational growth of water droplets, our kinetic model results provide a direct link between laboratory observations and molecular dynamic simulations, confirming that the accommodation coefficient of water at ~270 K is close to unity (Winkler et al., 2006). Literature data on the evaporation of dioctyl phthalate as a function of particle size and time can be reproduced, and the model results suggest that changes in the experimental conditions like aerosol particle concentration and chamber geometry may influence the evaporation kinetics and can be optimized for efficient probing of specific physical effects and parameters. With regard to oxidative aging of organic aerosol particles, we illustrate how the formation and evaporation of volatile reaction products like nonanal can cause a decrease in the size of oleic acid particles exposed to ozone.

  7. Relation between biomarkers in exhaled breath condensate and internal exposure to metals from gas metal arc welding.

    PubMed

    Hoffmeyer, Frank; Raulf-Heimsoth, Monika; Weiss, Tobias; Lehnert, Martin; Gawrych, Katarzyna; Kendzia, Benjamin; Harth, Volker; Henry, Jana; Pesch, Beate; Brüning, Thomas

    2012-06-01

    Concerning possible harmful components of welding fumes, besides gases and quantitative aspects of the respirable welding fumes, particle-inherent metal toxicity has to be considered.The objective of this study was to investigate the effect markers leukotriene B4 (LTB4),prostaglandin E2 (PGE2) and 8-isoprostane (8-Iso PGF2α) as well as the acid–base balance(pH) in exhaled breath condensate (EBC) of 43 full-time gas metal arc welders (20 smokers) in relation to welding fume exposure. We observed different patterns of iron, chromium and nickel in respirable welding fumes and EBC. Welders with undetectable chromium in EBC(group A, n = 24) presented high iron and nickel concentrations. In this group, higher 8-isoPGF2α and LTB4 concentrations could be revealed compared to welders with detectable chromium and low levels of both iron and nickel in EBC (group B): 8-iso PGF2α443.3 pg mL−1 versus 247.2 pg mL−1; p = 0.001 and LTB4 30.5 pg mL−1 versus 17.3 pgmL−1; p = 0.016. EBC-pH was more acid in samples of group B (6.52 versus 6.82; p = 0.011).Overall, effect markers in welders were associated with iron concentrations in EBC according to smoking habits--non-smokers/smokers: LTB4 (rs = 0.48; p = 0.02/rs = 0.21; p = 0.37),PGE2 (rs = 0.15; p = 0.59/rs = 0.47; p = 0.07), 8-iso PGF2α (rs = 0.18; p = 0.54/rs = 0.59;p = 0.06). Sampling of EBC in occupational research provides a matrix for the simultaneous monitoring of metal exposure and effects on target level. Our results suggest irritative effects in the airways of healthy welders. Further studies are necessary to assess whether these individual results might be used to identify welders at elevated risk for developing a respiratory disease. PMID:22622358

  8. Inert blanketing of a hydride bed using typical grade protium

    SciTech Connect

    Klein, J.E.

    2015-03-15

    This paper describes the impact of 500 ppm (0.05%) impurities in protium on the absorption rate of a 9.66 kg LaNi{sub 4.25}Al{sub 0.75} (LANA0.75) metal hydride bed. The presence of 500 ppm or less inerts (i.e. non-hydrogen isotopes) can significantly impact hydrogen bed absorption rates. The impact on reducing absorption rates is significantly greater than predicted assuming uniform temperature, pressure, and compositions throughout the bed. Possible explanations are discussed. One possibility considered was the feed gas contained impurity levels higher than 500 ppm. It was shown that a level of 5000 ppm of inerts would have been necessary to fit the experimental result so this possibility wa dismissed. Another possibility is that the impurities in the protium supply reacted with the hydride material and partially poisoned the hydride. If the hydride were poisoned with CO or another impurity, the removal of the over-pressure gas in the bed would not be expected to allow the hydride loading of the bed to continue as the experimental results showed, so this possibility was also dismissed. The last possibility questions the validity of the calculations. It is assumed in all the calculations that the gas phase composition, temperature, and pressure are uniform throughout the bed. These assumptions are less valid for large beds where there can be large temperature, pressure, and composition gradients throughout the bed. Eventually the impact of 0.05% inerts in protium on bed absorption rate is shown and explained in terms of an increase in inert partial pressure as the bed was loaded.

  9. A dynamic inert metal anode.

    SciTech Connect

    Hryn, J. N.

    1998-11-09

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

  10. Can hydrodynamic contact line paradox be solved by evaporation-condensation?

    PubMed

    Janeček, V; Doumenc, F; Guerrier, B; Nikolayev, V S

    2015-12-15

    We investigate a possibility to regularize the hydrodynamic contact line singularity in the configuration of partial wetting (liquid wedge on a solid substrate) via evaporation-condensation, when an inert gas is present in the atmosphere above the liquid. The no-slip condition is imposed at the solid-liquid interface and the system is assumed to be isothermal. The mass exchange dynamics is controlled by vapor diffusion in the inert gas and interfacial kinetic resistance. The coupling between the liquid meniscus curvature and mass exchange is provided by the Kelvin effect. The atmosphere is saturated and the substrate moves at a steady velocity with respect to the liquid wedge. A multi-scale analysis is performed. The liquid dynamics description in the phase-change-controlled microregion and visco-capillary intermediate region is based on the lubrication equations. The vapor diffusion is considered in the gas phase. It is shown that from the mathematical point of view, the phase exchange relieves the contact line singularity. The liquid mass is conserved: evaporation existing on a part of the meniscus and condensation occurring over another part compensate exactly each other. However, numerical estimations carried out for three common fluids (ethanol, water and glycerol) at the ambient conditions show that the characteristic length scales are tiny. PMID:26348659

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

    PubMed

    Cornell, Eric A; Wieman, Carl E

    2002-06-17

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

  12. Exhaled breath condensate: an overview.

    PubMed

    Davis, Michael D; Montpetit, Alison; Hunt, John

    2012-08-01

    Exhaled breath condensate (EBC) is a promising source of biomarkers of lung disease. EBC may be thought of either as a body fluid or as a condensate of exhaled gas. There are 3 principal contributors to EBC: variable-sized particles or droplets that are aerosolized from the airway lining fluid, distilled water that condenses from gas phase out of the nearly water-saturated exhalate, and water-soluble volatiles that are exhaled and absorbed into the condensing breath. The nonvolatile constituents and the water-soluble volatile constituents are of particular interest. Several key issues are discussed in this article. PMID:22877615

  13. Extinct 93Zr in Single Presolar SiC Grains from Low Mass Asymptotic Giant Branch Stars and Condensation from Zr-depleted Gas

    NASA Astrophysics Data System (ADS)

    Kashiv, Y.; Davis, A. M.; Gallino, R.; Cai, Z.; Lai, B.; Sutton, S. R.; Clayton, R. N.

    2010-04-01

    Synchrotron X-ray fluorescence was used in this study for the first time to measure trace element abundances in single presolar grains. The abundances of Zr and Nb were determined in SiC grains of the KJF size-separate. These grains are most likely from C-rich asymptotic giant branch stars (mainstream grains). Comparison of the data with s-process calculations suggests that the relatively short-lived isotope 93Zr (t 1/2 = 1.5 × 106 yr) condensed into the grains. The Nb/Zr ratios of the majority of the grains are higher than the s-process and CI chondrite ratios. This is probably due to grains condensing from stellar gas that was depleted in Zr, potentially because of earlier condensation of ZrC, but not depleted in Nb. However, grain contamination with solar system Nb is possible as well. Upper limits on the initial 93Zr/Zr ratios in the grains agree with the ratios observed in late-type S stars.

  14. CONDENSATION CAN

    DOEpatents

    Booth, E.T. Jr.; Pontius, R.B.; Jacobsohn, B.A.; Slade, C.B.

    1962-03-01

    An apparatus is designed for condensing a vapor to a solid at relatively low back pressures. The apparatus comprises a closed condensing chamber, a vapor inlet tube extending to the central region of the chamber, a co-axial tubular shield surrounding the inlet tube, means for heating the inlet tube at a point outside the condensing chamber, and means for refrigeratirg the said chamber. (AEC)

  15. Relativistic Quantum Chemistry of Heavy Elements: Interatomic potentials and Lines Shift for Systems 'Alkali Elements-Inert Gases'

    SciTech Connect

    Glushkov, A. V.; Khetselius, O.; Gurnitskaya, E.; Loboda, A.; Mischenko, E.

    2009-03-09

    New relativistic approach, based on the gauge-invariant perturbation theory (PT) with using the optimized wave functions basis's, is applied to calculating the inter atomic potentials, hyper fine structure (hfs) collision shift for alkali atoms in atmosphere of inert gases. Data for inter atomic potentials, collision shifts of the Rb and Cs atoms in atmosphere of the inert gas He are presented.

  16. 7 CFR 201.19 - Inert matter.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

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

  17. 7 CFR 201.19 - Inert matter.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

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

  18. Effects of proton irradiation on a gas phase in which condensation takes place. I Negative Mg-26 anomalies and Al-26. [applied to solar and meteoritic composition

    NASA Technical Reports Server (NTRS)

    Heymann, D.; Dziczkaniec, M.; Walker, A.; Huss, G.; Morgan, J. A.

    1978-01-01

    In the present paper, isotopic effects in magnesium generated in a proton-irradiated gas phase are examined, taking only (p,n), (p,d), and (p, alpha) reactions in magnesium, aluminum, and silicon into consideration. In the presence of proton radiation, the three elements are 'removed' from the gas phase by condensation. It is required that a value of Al-26/Al-27 greater than 6 times 10 to the -5th must be reached, consistent with the value deduced by Lee Papanastassiou, and Wasserburg (1976) from their studies of the Allende meteorite. The calculations show that fast aluminum condensation reduces the required proton fluence substantially, that a significant fraction of aluminum remains uncondensed when the above value of the Al-26/Al-27 ratio is reached, that a detectable MG-24 excess is very likely to occur, that detectable negative MG-28 anomalies can be generated, and that proton fluxes and irradiation times can be varied simultaneously, and over a wide range of values, without significant changes in the required proton fluence.

  19. Implementation of Sub-Cooling of Cryogenic Propellants by Injection of Non-condensing Gas to the Generalized Fluid Systems Simulation Program (GFSSP)

    NASA Technical Reports Server (NTRS)

    Huggett, Daniel J.; Majumdar, Alok

    2013-01-01

    Cryogenic propellants are readily heated when used. This poses a problem for rocket engine efficiency and effective boot-strapping of the engine, as seen in the "hot" LOX (Liquid Oxygen) problem on the S-1 stage of the Saturn vehicle. In order to remedy this issue, cryogenic fluids were found to be sub-cooled by injection of a warm non-condensing gas. Experimental results show that the mechanism behind the sub-cooling is evaporative cooling. It has been shown that a sub-cooled temperature difference of approximately 13 deg F below saturation temperature [1]. The phenomenon of sub-cooling of cryogenic propellants by a non-condensing gas is not readily available with the General Fluid System Simulation Program (GFSSP) [2]. GFSSP is a thermal-fluid program used to analyze a wide variety of systems that are directly impacted by thermodynamics and fluid mechanics. In order to model this phenomenon, additional capabilities had to be added to GFSSP in the form of a FORTRAN coded sub-routine to calculate the temperature of the sub-cooled fluid. Once this was accomplished, the sub-routine was implemented to a GFSSP model that was created to replicate an experiment that was conducted to validate the GFSSP results.

  20. Dynamics of galloping detonations: inert hydrodynamics with pulsed energy release

    NASA Astrophysics Data System (ADS)

    Radulescu, Matei I.; Shepherd, Joseph E.

    2015-11-01

    Previous models for galloping and cellular detonations of Ulyanitski, Vasil'ev and Higgins assume that the unit shock decay or cell can be modeled by Taylor-Sedov blast waves. We revisit this concept for galloping detonations, which we model as purely inert hydrodynamics with periodically pulsed energy deposition. At periodic time intervals, the chemical energy of the non-reacted gas accumulating between the lead shock and the contact surface separating reacted and non reacted gas is released nearly instantaneously. In between these pulses, the gas evolves as an inert medium. The resulting response of the gas to the periodic forcing is a sudden gain in pressure followed by mechanical relaxation accompanied by strong shock waves driven both forward and backwards. It is shown that the decay of the lead shock in-between pulses follows an exponential decay, whose time constant is controlled by the frequency of the energy deposition. More-over, the average speed of the lead shock is found to agree within 2 percent to the ideal Chapman-Jouguet value, while the large scale dynamics of the wave follows closely the ideal wave form of a CJ wave trailed by a Taylor expansion. When friction and heat losses are accounted for, velocity deficits are predicted, consistent with experiment. Work performed while MIR was on sabbatical at Caltech.

  1. Non-inert refrigerant study for automotive applications

    SciTech Connect

    Dieckmann, J.T.; Bentley, J.; Varone, A.

    1991-11-01

    Alternatives to CFC-12 for automobile air conditioning were examined. The list of candidate fluids included flammable as well as non-flammable substances. HFC-134a was taken as the baseline alternative given current industry plans to convert automobile air conditioning systems to this fluid over the next several years. Three flammable (non-inert) altemative refrigerants -- BFC-152a, HC-290 (propane) and HC-270 (cyclopropane) were identified. Air conditioning cycle efficiency, ozone depletion potential, and global warming impacts of these three fluids and HFC-134a were compared, with the three non-inert fluids all having higher COP and lower global warming impact. The ozone depletion potential of each of these fluids is zero. The fire safety implications of the flammable alternatives being used in otherwise conventional automobile air conditioning systems were examined in preliminary fashion. The results, which are subject to more extensive verification indicate that the additional passenger compartment fire risk would be very small, while the incidence of engine compartment fires would increase modestly. The engine compartment fire hazard could be minimized by modest design changes to reduce the occurrence of ignition sources and condenser punctures in front end collisions.

  2. The intercombination Cd line 326.1 nm and van der Waals potential coefficients ΔC60andΔC61 for pure Cd and Cd-inert gas systems

    NASA Astrophysics Data System (ADS)

    Roston, G. D.; Helmi, M. S.

    2009-03-01

    The absorption profiles of the Cd 326.1 nm line for pure Cd and Cd-inert gases (Xe, Kr, Ar, Ne and He) have been carefully studied from the line center to 700 cm -1 in the red wing using a high resolution double beam spectrometer. The density of Cd was about 5.108 × 10 18 atoms cm -3. The temperature dependences of the red wings of these profiles were analysed in the frame work of the Unified Frank Condon (UFC) treatment of pressure broadening of spectral lines developed by Szudy and Baylis. The van der Waals potential coefficient differences ΔC60 and ΔC61 between the ground 10 + state and the two excited states 30 + and 31 were obtained using Kuhn's law.

  3. The van der Waals Potential Coefficients ΔC60 and ΔC61 of the Intercombination Cd Line 326.1 nm for Pure Cd and Cd-Inert Gas Systems

    NASA Astrophysics Data System (ADS)

    Roston, G. D.; Helmi, M. S.

    2008-10-01

    The absorption profiles of the Cd 326.1 nm line for pure Cd and Cd-inert gases (Xe, Kr, Ar, Ne and He) have been carefully studied from the line center to 700 cm-1 in the red wing using a high resolution double beam spectrometer. The density of Cd was about 5.108×1018 atoms cm-3. The temperature dependences of the red wings of these profiles were analysed in the frame work of the unified Frank Condon (UFC) treatment of pressure broadening of spectral lines developed by Szudy and Baylis. The van der Waals potential coefficient differences ΔC60 and ΔC61 between the ground 30+ state and the two exited states 30+ and 31 were obtained using Kuhn's law.

  4. Evidence for a palaeo-oil column and alteration of residual oil in a gas-condensate field: Integrated oil inclusion and experimental results

    NASA Astrophysics Data System (ADS)

    Bourdet, Julien; Burruss, Robert C.; Chou, I.-Ming; Kempton, Richard; Liu, Keyu; Hung, Nguyen Viet

    2014-10-01

    In the Phuong Dong gas condensate field, Cuu Long Basin, Vietnam, hydrocarbon inclusions in quartz trapped a variety of petroleum fluids in the gas zone. Based on the attributes of the oil inclusion assemblages (fluorescence colour of the oil, bubble size, presence of bitumen), the presence of a palaeo-oil column is inferred prior to migration of gas into the reservoir. When a palaeo-oil column is displaced by gas, a residual volume fraction of oil remains in pores. If the gas does not completely mix with the oil, molecular partitioning between the residual oil and the new gas charge may change the composition and properties of the residual oil (gas stripping or gas washing). To simulate this phenomenon in the laboratory, we sealed small amounts of crude oil (42 and 30 °API) and excess pure gas (methane, ethane, or propane) in fused silica capillary capsules (FSCCs), with and without water. These mixtures were characterized with the same methods used to characterize the fluid inclusions, heating and cooling stage microscopy, fluorescence spectroscopy, synchrotron FT-IR, and Raman spectroscopy. At room temperature, mixtures of ethane and propane with the 30 °API oil formed a new immiscible fluorescent liquid phase with colour that is visually more blue than the initial oil. The fluorescence of the original oil phase shifted to yellow or disappeared with formation of semi-solid residues. The blue-shift of the fluorescence of the immiscible phases and strong CH stretching bands in FT-IR spectra are consistent with stripping of hydrocarbon molecules from the oil. In experiments in FSCCs with water solid residues are common. At elevated temperature, reproducing geologic reservoir conditions, the fluorescence changes and therefore the molecular fractionation are enhanced. However, the precipitation of solid residues is responsible of more complex changes. Mixing experiments with the 42 °API oil do not form a new immiscible hydrocarbon liquid although the fluorescence displays a similar yellow shift when gas is added. Solid residues rarely form in mixtures with 42 °API oil. FT-IR spectra suggest that the decrease of fluorescence intensity of the original oil at short wavelengths to be due to the partitioning of low molecular weight aromatic molecules into the vapour phase and/or the new immiscible liquid phase. The decrease of fluorescence intensity at long wavelengths appears to be due to loss of high molecular weight aromatics during precipitation of solid residues by desorption of aromatics and resins from asphaltenes. Desorption of low molecular weight aromatics and resins from asphaltenes during precipitation can also increase the fluorescence intensity at short wavelengths of the residual oil. Water clearly affects the precipitation of semi-solid residues from the oil phase of the lowest API gravity oil. The change of hydrocarbon phase(s) in UV-visible fluorescence and FT-IR enclosed within the FSCCs were compared with the fluorescence patterns of natural fluid inclusions at Phuong Dong gas condensate field. The experimental results support the concept of gas-washing of residual oil and are consistent with the oil inclusion attributes from the current gas zone at Phuong Dong field. The hydrocarbon charge history of the fractured granite reservoir is interpreted to result from the trapping of residual oil after drainage of a palaeo-oil column by gas.

  5. Effect of precursor supply on structural and morphological characteristics of fe nanomaterials synthesized via chemical vapor condensation method.

    PubMed

    Ha, Jong-Keun; Ahn, Hyo-Jun; Kim, Ki-Won; Nam, Tae-Hyun; Cho, Kwon-Koo

    2012-01-01

    Various physical, chemical and mechanical methods, such as inert gas condensation, chemical vapor condensation, sol-gel, pulsed wire evaporation, evaporation technique, and mechanical alloying, have been used to synthesize nanoparticles. Among them, chemical vapor condensation (CVC) has the benefit of its applicability to almost all materials because a wide range of precursors are available for large-scale production with a non-agglomerated state. In this work, Fe nanoparticles and nanowires were synthesized by chemical vapor condensation method using iron pentacarbonyl (Fe(CO)5) as the precursor. The effect of processing parameters on the microstructure, size and morphology of Fe nanoparticles and nanowires were studied. In particular, we investigated close correlation of size and morphology of Fe nanoparticles and nanowires with atomic quantity of inflow precursor into the electric furnace as the quantitative analysis. The atomic quantity was calculated by Boyle's ideal gas law. The Fe nanoparticles and nanowires with various diameter and morphology have successfully been synthesized by the chemical vapor condensation method. PMID:22524015

  6. Diamondoid Characterization in Condensate by Comprehensive Two-Dimensional Gas Chromatography with Time-of-Flight Mass Spectrometry: The Junggar Basin of Northwest China

    PubMed Central

    Li, Shuifu; Hu, Shouzhi; Cao, Jian; Wu, Ming; Zhang, Dongmei

    2012-01-01

    Diamondoids in crude oil are useful for assessing the maturity of oil in high maturation. However, they are very difficult to separate and accurately quantify by conventional geochemical methods due to their low abundance in oil. In this paper, we use comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC×GC-TOFMS) to study the compounds in condensates from the Junggar Basin of northwest China and address their geological and geochemical applications. GC×GC-TOFMS improves the resolution and separation efficiency of the compounds. It not only separates the compounds that coelute in conventional GC-MS (e.g., 4, 8-dimethyl-diamantane and trimethyl-diamantane) but also allows the identification of compounds that were not previously detected (e.g., trimethyl-diamantane (15A)). A reversed-phase column system improves the separation capabilities over the normal phase column system. The diamondoid indexes indicate that a representative condensate from Well DX 10 is highly mature with equivalent Ro being approximately 1.5%. PMID:23109861

  7. Characterization of cigarette smoke condensates by comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC x GC/TOFMS). Part 2: basic fraction.

    PubMed

    Lu, Xin; Zhao, Mingyue; Kong, Hongwei; Cai, Junlan; Wu, Jianfang; Wu, Ming; Hua, Ruixiang; Liu, Jianfu; Xu, Guowang

    2004-01-01

    Cigarette smoke condensate is a complex chemical matrix. Analysis of nitrogen-containing compounds present therein is very difficult because of the limitation of the peak capacity of conventional one-dimensional chromatography. Extensive and laborious sample preparation is frequently required or selective detectors are frequently used. In this study, the basic fraction of mainstream cigarette smoke condensate has been investigated by using comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC x GC/TOFMS). Auto data processing by TOFMS software combined with manual identification was used to assign the components. 377 nitrogen-containing compounds, including 155 pyridine derivatives, 104 quinoline/isoquinoine derivatives, and 56 pyrazine derivatives were tentatively identified. By selecting appropriate unique masses and in the light of the component positions in the structured chromatogram, alkyl-substituted pyridines, pyrazines, and quinolines/isoquinolines were separately shown and further validated. The peaks of eight individual positional isomers of two-carbon-substituted pyridines and thirteen positional isomers of methyl-substituted quinolines/isoquinolines were further confirmed, based on linear incremental retention behavior in combination with TOFMS and the structured chromatogram of GC x GC. PMID:15335065

  8. Performance of an adjustable, threaded inertance tube

    NASA Astrophysics Data System (ADS)

    Zhou, W. J.; Pfotenhauer, J. M.; Nellis, G. F.; Liu, S. Y.

    2015-12-01

    The performance of the Stirling type pulse tube cryocooler depends strongly on the design of the inertance tube. The phase angle produced by the inertance tube is very sensitive to its diameter and length. Recent developments are reported here regarding an adjustable inertance device that can be adjusted in real time. The inertance passage is formed by the root of a concentric cylindrical threaded device. The depth of the threads installed on the outer screw varies. In this device, the outer screw can be rotated four and half turns. At the zero turn position the length of the passage is 1.74 m and the hydraulic diameter is 7 mm. By rotating the outer screw, the inner threaded rod engages with additional, larger depth threads. Therefore, at its upper limit of rotation, the inertance passage includes both the original 1.74 m length with 7mm hydraulic diameter plus an additional 1.86 m length with a 10 mm hydraulic diameter. A phase shift change of 24° has been experimentally measured by changing the position of outer screw while operating the device at a frequency of 60 Hz. This phase angle shift is less than the theoretically predicted value due to the presence of a relatively large leak through the thread clearance. Therefore, the distributed component model of the inertance tube was modified to account for the leak path causing the data to agree with the model. Further, the application of vacuum grease to the threads causes the performance of the device to improve substantially.

  9. Analysis of t-butylphenol acetylene condensed resin with methyl-methine linkages in vulcanized rubber by pyrolysis-gas chromatography/mass spectrometry

    PubMed

    Kim; Lee

    1999-01-01

    Methyl-methine linkages of Novolac, a commercially available t-butylphenol acetylene condensed (TBPA) resin, have been identified by recognition of pyrolysis pathways using pyrolysis-gas chromatography/mass spectrometry (Py-GC/mS) in vulcanized rubber. The diagnostic mass spectrum of t-butylphenol with methyl-methine linkages between phenolic rings was observed at m/z 192, corresponding to 4-t-butyl-2-ethyl-6-methylphenol. Other molecular ions were observed at m/z 178, 164, and 150 in the characteristic pyrolyzates. The ion at m/z 192 in the TBPA resin was observed to be characteristic for methyl-methine linkages between the phenolic groups, and the analytical pyrolysis-GC/mS method was thus able to identify the resin at low levels in vulcanized rubber. Copyright 1999 John Wiley & Sons, Ltd. PMID:10482900

  10. The effect of the physical properties of the tube wall on the attenuation of sound in evaporating and condensing gas-vapor mixtures

    PubMed

    Slaton; Raspet; Hickey

    2000-11-01

    An investigation of sound propagation in an air-water vapor mixture contained in a cylindrical tube with wet walls was recently completed [Hickey et al., J. Acoust. Soc. Am. 107, 1126-1130 (2000)]. A generalization to include the heat flux at the tube wall is presented here. The attenuation of sound in air-water vapor mixtures can be affected by the thermal properties of the tube wall. The controlling parameter is epsilons, which is a proportionality constant that relates the heat flux per degree Kelvin for the substrate to that of the gas mixture. For a given amount of heat, provided by expansion and rarefaction of the working fluid, different substrates will undergo different temperature excursions. These temperature swings at the boundary change the vapor pressure of the condensate and thus reduce the diffusion of vapor to and from the boundary resulting in a reduction of the attenuation. PMID:11108349

  11. Inert strength of pristine silica glass fibers

    SciTech Connect

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

    1993-11-01

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

  12. Condensation polyimides

    NASA Technical Reports Server (NTRS)

    Hergenrother, P. M.

    1989-01-01

    Polyimides belong to a class of polymers known as polyheterocyclics. Unlike most other high temperature polymers, polyimides can be prepared from a variety of inexpensive monomers by several synthetic routes. The glass transition and crystalline melt temperature, thermooxidative stability, toughness, dielectric constant, coefficient of thermal expansion, chemical stability, mechanical performance, etc. of polyimides can be controlled within certain boundaries. This versatility has permitted the development of various forms of polyimides. These include adhesives, composite matrices, coatings, films, moldings, fibers, foams and membranes. Polyimides are synthesized through both condensation (step-polymerization) and addition (chain growth polymerization) routes. The precursor materials used in addition polyimides or imide oligomers are prepared by condensation method. High molecular weight polyimide made via polycondensation or step-growth polymerization is studied. The various synthetic routes to condensation polyimides, structure/property relationships of condensation polyimides and composite properties of condensation polyimides are all studied. The focus is on the synthesis and chemical structure/property relationships of polyimides with particular emphasis on materials for composite application.

  13. Condensation Processes in Geothermal Systems

    NASA Astrophysics Data System (ADS)

    Norman, D. I.; Moore, J. N.

    2005-12-01

    We model condensation processes in geothermal systems to understand how this process changes fluid chemistry. We assume two processes operate in geothermal systems: 1) condensation of a vapor phase derived by boiling an aqueous geothermal fluid into a cool near surface water and 2) condensation of a magmatic vapor by a deep circulating meteoric thermal fluid. It is assumed that the condensation process has two stages. Initially the condensing fluid is under saturated in gaseous species. Condensation of the vapor phase continues until the pressure on the fluid equals the sum of the partial pressures of water and the dissolved gaseous species. At that time bubbles flux through the condensing fluid. In time the fluid and fluxing gas phase come to equilibrium. Calculation shows that during the second stage of the condensation process the liquid phase becomes enriched in more soluble gaseous species like CO2 and H2S, and depleted in less soluble species like CH4 and N2. Stage 2 condensation processes can therefore be monitored by ratios of more and less condensable species like CO2/N2. Condensation of vapor released by boiling geothermal fluids results in liquids with high concentrations of H2S and CO2 like is seen in geothermal system steam-heated waters. Condensation of a magmatic vapor into circulating meteoric water has been proposed, but not well demonstrated. We compare to our models the Cerro Prieto, Mexico gas analysis data set collected over twelve years time by USGS personnel. It was assumed for modeling that the Cerro Prieto geothermal fluids are circulating meteoritic fluids with N2/Ar ratios about 40 to which is added a magmatic vapor with N2/Ar ratio = 400. The Cerro Prieto analyses show a strong correlation between N2/Ar and CO2/N2 as predicted by calculation. Two dimensional image plots of well N2/Ar + CO2/N2 show a bull's-eye pattern on the geothermal field. Image plots of analyses collected over a year or less time show N2/Ar and CO2/N2 hot spots. Plotting data for individual wells show a hysteresis like loops on time vs. CO2/N2 diagrams. Our analysis demonstrates that condensation of magmatic vapor into convecting meteoric waters is a viable process. Condensation explains variations in Cerro Prieto geothermal system gas chemistry and is compatible with helium isotope data. Locally condensation appears to wax and wane over a time periods of about 10 years.

  14. 7 CFR 201.51 - Inert matter.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

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

  15. 7 CFR 201.51 - Inert matter.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

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

  16. 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.

  17. Equilibrium condensation in a solar nebula

    NASA Technical Reports Server (NTRS)

    Arrhenius, G.; De, R. R.

    1973-01-01

    In attempts to reconstruct the environment of condensation of solar system materials, particularly exemplified by certain meteorite components, the relative temperatures of the gas and the solid are of critical importance. The relationships that determine the heat balance in a circumsolar grain-gas system are examined. Fundamental considerations show that regardless of opacity or gas density, the gas will always be at a higher temperature than the solid in such regions of the system where condensation is possible. Implications of the characteristic temperature differential between the gas and the condensing solid are discussed.

  18. Dropwise condensation

    PubMed Central

    Leach, R. N.; Stevens, F.; Langford, S. C.; Dickinson, J. T.

    2008-01-01

    Dropwise condensation of water vapor from a naturally cooling, hot water reservoir onto a hydrophobic polymer film and a silanized glass slide was studied by direct observation and simulations. The observed drop growth kinetics suggest that smallest drops grow principally by the diffusion of water adsorbed on the substrate to the drop perimeter, while drops larger than 50 μm in diameter grow principally by direct deposition from the vapor onto the drop surface. Drop coalescence plays a critical role in determining the drop size distribution, and stimulates the nucleation of new, small drops on the substrates. Simulations of drop growth incorporating these growth mechanisms provide a good description of the observed drop size distribution. Because of the large role played by coalescence, details of individual drop growth make little difference to the final drop size distribution. The rate of condensation per unit substrate area is especially high for the smallest drops, and may help account for the high heat transfer rates associated with dropwise condensation relative to filmwise condensation in heat exchange applications. PMID:17014129

  19. Formation of Globular Clusters in Atomic-cooling Halos Via Rapid Gas Condensation and Fragmentation during the Epoch of Reionization

    NASA Astrophysics Data System (ADS)

    Kimm, Taysun; Cen, Renyue; Rosdahl, Joakim; Yi, Sukyoung K.

    2016-05-01

    We investigate the formation of metal-poor globular clusters (GCs) at the center of two dark matter halos with {M}{{halo}}∼ 4× {10}7 {M}ȯ at z\\gt 10 using cosmological radiation-hydrodynamics simulations. We find that very compact (≲1 pc) and massive (∼ 6× {10}5 {M}ȯ ) clusters form rapidly when pristine gas collapses isothermally with the aid of efficient Lyα emission during the transition from molecular-cooling halos to atomic-cooling halos. Because the local free-fall time of dense star-forming gas is very short (\\ll 1 {{Myr}}), a large fraction of the collapsed gas is turned into stars before stellar feedback processes blow out the gas and shut down star formation. Although the early stage of star formation is limited to a small region of the central star-forming disk, we find that the disk quickly fragments due to metal enrichment from supernovae. Sub-clusters formed in the fragmented clouds eventually merge with the main cluster at the center. The simulated clusters closely resemble the local GCs in mass and size but show a metallicity spread that is much wider than found in the local GCs. We discuss a role of pre-enrichment by Pop III and II stars as a potential solution to the latter issue. Although not without shortcomings, it is encouraging that a naive blind (not tuned) cosmological simulation presents a possible channel for the formation of at least some massive GCs.

  20. Infinite statistics condensate as a model of dark matter

    SciTech Connect

    Ebadi, Zahra; Mirza, Behrouz; Mohammadzadeh, Hosein E-mail: b.mirza@cc.iut.ac.ir

    2013-11-01

    In some models, dark matter is considered as a condensate bosonic system. In this paper, we prove that condensation is also possible for particles that obey infinite statistics and derive the critical condensation temperature. We argue that a condensed state of a gas of very weakly interacting particles obeying infinite statistics could be considered as a consistent model of dark matter.

  1. Herbert P. Broida Prize Talk: Molecular photofragmentation dynamics in the gas and condensed phase: similarities and differences

    NASA Astrophysics Data System (ADS)

    Ashfold, Michael

    2015-03-01

    Phenols and azoles are important chromophores in the nucleobases and aromatic amino-acids that dominate the near-UV absorption spectra of many biological molecules. π* <-- π excitations are responsible for these strong UV absorptions, but these molecules also possess excited states formed from σ* <-- π electron promotions. πσ * excited states typically have much smaller absorption cross-sections, but their photochemical importance is becoming ever more widely recognized. We have used photofragment translational spectroscopy (PTS) methods (and complementary ab initio theory) to explore X-H bond fission (X = heteroatom) following UV photoexcitation of many such heteroaromatic molecules in the gas phase and, more recently, started ultrafast pump-probe studies of the same (and related) processes in solution. This presentation will (i) summarize the state of knowledge derived from PTS studies of phenol and related molecules in the gas phase, (ii) highlight the extent to which such knowledge can inform our interpretation of ultrafast pump-probe studies of the UV photofragmentation of similar molecules ((thio)phenols, anisoles and ethers) in solution and (iii) demonstrate how such solution phase studies offer a route to exploring photoinduced (πσ *-state mediated) ring opening of heterocyclic molecules like furans and thiophenes. Funding from EPSRC (EP/G00224X and EP/L005913) is gratefully acknowledged.

  2. A plagioclase-olivine-spinel-magnetite inclusion from Maralinga (CK): evidence for sequential condensation and solid-gas exchange

    NASA Astrophysics Data System (ADS)

    Kurat, Gero; Zinner, Ernst; Brandstätter, Franz

    2002-09-01

    We report a detailed petrography, mineral chemistry, and trace element study of MaTroc, a large calcium-aluminum-rich inclusion (CAI) (5 × 2.5 mm) of irregular triangular shape. The inclusion has a zonal structure: The core consists of a porous plagioclase-olivine-Ca-rich pyroxene intergrowth with subordinate apatite. Its texture is meta-gabbro-like, similar to other plagioclase-olivine inclusions (POIs). The mantle has variable thickness (0.1-1.5 mm) and consists of a compact symplectitic intergrowth of spinel (hercynite) and plagioclase with abundant dispersed magnetite, subordinate Ca-rich pyroxene, and traces of sulfides. The thin (5-50 μm) discontinuous crust of MaTroc consists mainly of plagioclase with some olivine and magnetite. The Mg-Fe phases of MaTroc are Fe-rich: olivine has Fa33.2 and high NiO content, similar to that in the host rock, Ca-rich pyroxene has much lower TiO 2 and Cr 2O 3 contents than that of the host chondrite, and plagioclase is An55-An74. Magnetites have variable compositions, are poorer in Al 2O 3 and Cr 2O 3 and richer in NiO than those in the host. Spinels have also variable compositions, rich in FeO, NiO, and ZnO. Despite their different mineralogy, both core and mantle have bulk trace element abundances similar to those in average group II CAIs. However, the mantle is richer in Nb and U and poorer in Eu, Be, B, Sr, and Li than the core. All minerals have high trace element contents. Minerals in the core show signs of incomplete equilibration of trace elements within and between them. Mantle minerals are far from equilibrium with each other and the bulk system. Spinel and anorthite carry the trace element signature of their precursor melilite (or hibonite), and magnetite contains large amounts of a heterogeneously distributed remnant extremely rich in trace elements ("obscurite"), possibly of a former perovskite. Inclusion MaTroc has a complex history. The POI core probably formed by reaction of an unknown precursor(s) of condensation origin with a vapor to form olivine, plagioclase, clinopyroxene, apatite, and (an) unknown phase(s) that vanished, leaving abundant void space. The spinel-rich mantle is also a secondary mineral assemblage that formed by breakdown of and solid-vapor reactions with a precursor or precursors, possibly melilite (or hibonite). The abundant magnetite formed by reaction of perovskite with an oxidizing vapor and by precipitation from such a vapor. All phases of the inclusion experienced the metasomatic addition of Fe, Ni, and moderately volatile elements such as V, Be, Li, Cr, and Mn - similar to all other constituents of the Maralinga CK chondrite. Phases in MaTroc and in the host rock are close to equilibrium in the distribution of Fe, Mg, Ni, and Mn but far from equilibrium in the distribution of M +3 and M +4 ions. The minor and trace element abundances in the magnetite of the host rock and of MaTroc preclude an origin by oxidation of a metal precursor.

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

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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

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

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Inerted spaces: Relief devices. 154.912 Section 154.912... Atmospheric Control in Cargo Containment Systems § 154.912 Inerted spaces: Relief devices. Inerted spaces must be fitted with relief valves, rupture discs, or other devices specially approved by the...

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

    Code of Federal Regulations, 2014 CFR

    2014-10-01

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

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

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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

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

    Code of Federal Regulations, 2013 CFR

    2013-10-01

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

  8. 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.

  9. Inhibition of hydrogen sulfide, methane, and total gas production and sulfate-reducing bacteria in in vitro swine manure by tannins, with focus on condensed quebracho tannins.

    PubMed

    Whitehead, Terence R; Spence, Cheryl; Cotta, Michael A

    2013-09-01

    Management practices from large-scale swine production facilities have resulted in the increased collection and storage of manure for off-season fertilization use. Odor and emissions produced during storage have increased the tension among rural neighbors and among urban and rural residents. Production of these compounds from stored manure is the result of microbial activity of the anaerobic bacteria populations during storage. In the current study, the inhibitory effects of condensed quebracho tannins on in vitro swine manure for reduction of microbial activity and reduced production of gaseous emissions, including the toxic odorant hydrogen sulfide produced by sulfate-reducing bacteria (SRB), was examined. Swine manure was collected from a local swine facility, diluted in anaerobic buffer, and mixed with 1 % w/v fresh feces. This slurry was combined with quebracho tannins, and total gas and hydrogen sulfide production was monitored over time. Aliquots were removed periodically for isolation of DNA to measure the SRB populations using quantitative PCR. Addition of tannins reduced overall gas, hydrogen sulfide, and methane production by greater than 90 % after 7 days of treatment and continued to at least 28 days. SRB population was also significantly decreased by tannin addition. qRT-PCR of 16S rDNA bacteria genes showed that the total bacterial population was also decreased in these incubations. These results indicate that the tannins elicited a collective effect on the bacterial population and also suggest a reduction in the population of methanogenic microorganisms as demonstrated by reduced methane production in these experiments. Such a generalized effect could be extrapolated to a reduction in other odor-associated emissions during manure storage. PMID:23149758

  10. Absorption removal of sulfur dioxide by falling water droplets in the presence of inert solid particles

    NASA Astrophysics Data System (ADS)

    Liu, I.-Hung; Chang, Ching-Yuan; Liu, Su-Chin; Chang, I.-Cheng; Shih, Shin-Min

    An experimental analysis of the absorption removal of sulfur dioxide by the free falling water droplets containing the inert solid particles is presented. The wheat flour powder is introduced as the inert solid particles. Tests with and without the flour powder in the water droplets are examined. The mass fluxes and mass transfer coefficients of SO 2 for the cases with and without the flour powder are compared to elucidate the effects of the inert solid particles contained in the water droplets on the gas absorption. The results indicate aignificant difference between the two cases for the concentrations of the flour powder in the absorbent droplets ( Cs) within the ranges of the experimental conditions, namely 0.1 to 10 wt% flour powder in the absorbent droplets. In general, the inert solid particles of the flour powder as the impurities in the water droplets tend to decrease the SO 2 absorption rate for the experimental absorption system under investigation. Various values of Cs cause various levels of the interfacial resistance and affect the gas absorption rate. The interfacial resistance is recognized by introducing an interfacial mass transfer coefficient ks with its reciprocal being proportional to the magnitude of the interfacial resistance. The values of 1/ ks may be computed by the use of the equation 1/ ks=(1/ KOLs-1/ KOL), where KOLs and KOL are the overall liquid-phase mass transfer coefficients with and without the inert solid particles, respectively. The values of ks with Cs of 0.1 to 10 wt% are about 0.295-0.032 cms -1 for absorbing 1000-3000 ppmv SO 2 with the water droplets. This kind of information is useful for the SO 2 removal and the information of acid rain that the impurities of the inert solid particles contaminate the water droplets.

  11. Condensation processes and the formation of cosmic grains

    NASA Technical Reports Server (NTRS)

    Donn, B.

    1978-01-01

    The case of condensation from a gas in the absence of any preexisting grains or nuclei upon which condensation can occur is considered. Some of the analysis is expected to apply to condensation on grains already present. An attempt is made to examine the basic assumptions of the various procedures used to describe condensation and to examine their applicability to astronomical systems. Attention is given to thermodynamic equilibration calculations, nucleation theory, kinetic mechanisms, the theoretical mechanisms, and condensation experiments.

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

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

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

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

    PubMed

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

    2015-10-01

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

  15. Condensate handling means for condensing furnace

    SciTech Connect

    Tomlinson, R. S.; Trent, B. O.

    1985-10-01

    An improved condensate neutralizer for use in a high efficiency furnace utilizing hydrocarbon gaseous fuel wherein acidic liquid condensate forms. The neutralizer is provided with a bypass for conducting the condensate from the furnace directly to a drain without passing through the neutralizer in the event condensate flow through the neutralizer becomes substantially impeded. Also disclosed is structure for indicating substantial impediment of flow of the condensate through the neutralizer for alerting the user to the need of servicing of the neutralizer. A separator/trap is provided for transferring the condensate from the furnace selectively to the neutralizer or bypass.

  16. Leptogenesis, radiative neutrino masses and inert Higgs triplet dark matter

    NASA Astrophysics Data System (ADS)

    Lu, Wen-Bin; Gu, Pei-Hong

    2016-05-01

    We extend the standard model by three types of inert fields including Majorana fermion singlets/triplets, real Higgs singlets/triplets and leptonic Higgs doublets. In the presence of a softly broken lepton number and an exactly conserved Z2 discrete symmetry, these inert fields together can mediate a one-loop diagram for a Majorana neutrino mass generation. The heavier inert fields can decay to realize a successful leptogenesis while the lightest inert field can provide a stable dark matter candidate. As an example, we demonstrate the leptogenesis by the inert Higgs doublet decays. We also perform a systematic study on the inert Higgs triplet dark matter scenario where the interference between the gauge and Higgs portal interactions can significantly affect the dark matter properties.

  17. A model with two inert scalar doublets

    NASA Astrophysics Data System (ADS)

    Machado, A. C. B.; Pleitez, V.

    2016-01-01

    We consider an extension of the standard model (SM) with three SU(2) scalar doublets and discrete S3 ⊗Z2 symmetries. The irreducible representation of S3 has a singlet and a doublet, and here we show that the singlet corresponds to the SM-like Higgs and the two additional SU(2) doublets forming a S3 doublet are inert. In general, in a three scalar doublet model, with or without S3 symmetry, the diagonalization of the mass matrices implies arbitrary unitary matrices. However, we show that in our model these matrices are of the tri-bimaximal type. We also analyzed the scalar mass spectra and the conditions for the scalar potential is bounded from below at the tree level. We also discuss some phenomenological consequences of the model.

  18. a Non-Tube Inertance Device for Pulse Tube Cryocoolers

    NASA Astrophysics Data System (ADS)

    Yuan, S. W. K.; Curran, D. G. T.; Cha, J. S.

    2010-04-01

    Inertance Pulse Tube Cryocoolers make use of a long tube for phase shifting and optimization of performance. This long tube presents a challenge for packaging in most applications, and is also a concern for environments where vibration is present (e.g., launch). In the present invention, a gap configuration is used in place of the tube, resulting in a more compact inertance device. Using the SAGE software, the performance of this new device is found to be comparable to that of an inertance tube. Significantly, this new invention offers the flexibility to change the inertance value during testing and operation, which cannot be done with the tube configuration.

  19. Simple Techniques For Assessing Impacts Of Oil And Gas Operations On Public Lands: A Field Evaluation Of A Photoionization Detector (PID) At A Condensate Release Site, Padre Island National Seashore, Texas

    USGS Publications Warehouse

    Otton, James K.; Zielinski, Robert A.

    2001-01-01

    Simple, cost-effective techniques are needed for land managers to assess the environmental impacts of oil and gas production activities on public lands, so that sites may be prioritized for remediation or for further, more formal assessment. Field-portable instruments provide real-time data and allow the field investigator to extend an assessment beyond simply locating and mapping obvious disturbances. Field investigators can examine sites for the presence of hydrocarbons in the subsurface using a soil auger and a photoionization detector (PID). The PID measures volatile organic compounds (VOC) in soil gases. This allows detection of hydrocarbons in the shallow subsurface near areas of obvious oil-stained soils, oil in pits, or dead vegetation. Remnants of a condensate release occur in sandy soils at a production site on the Padre Island National Seashore in south Texas. Dead vegetation had been observed by National Park Service personnel in the release area several years prior to our visit. The site is located several miles south of the Malaquite Beach Campground. In early 2001, we sampled soil gases for VOCs in the area believed to have received the condensate. Our purpose in this investigation was: 1) to establish what sampling techniques might be effective in sandy soils with a shallow water and contrast them with techniques used in an earlier study; and 2) delineate the probable area of condensate release. Our field results show that sealing the auger hole with a clear, rigid plastic tube capped at the top end and sampling the soil gas through a small hole in the cap increases the soil VOC gas signature, compared to sampling soil gases in the bottom of an open hole. This sealed-tube sampling method increases the contrast between the VOC levels within a contaminated area and adjacent background areas. The tube allows the PID air pump to draw soil gas from the volume of soil surrounding the open hole below the tube in a zone less influenced by atmospheric air. In an open hole, the VOC readings seem to be strongly dependent on the degree of diffusion and advection of soil gas VOCs into the open hole from the surrounding soil, a process that may vary with soil and wind conditions. Making measurements with the sealed hole does take some additional time (4-7 minutes after the hole is augered) compared to the open-hole technique (1-2 minutes). We used the rigid-plastic tube technique to survey for soil gas VOCs across the entire site, less than ? acre. Condensate has impacted at least 0.28 acres. The impacted area may extend northwest of the surveyed area.

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

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... operations, a crew member monitors the instrumentation under 46 CFR 32.53-60(a)(1), except if that instrumentation has an alarm that sounds in the cargo control room when the oxygen content exceeds 8 percent...

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

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... operations, a crew member monitors the instrumentation under 46 CFR 32.53-60(a)(1), except if that instrumentation has an alarm that sounds in the cargo control room when the oxygen content exceeds 8 percent...

  2. Simple device facilitates inert-gas welding of tubes

    NASA Technical Reports Server (NTRS)

    Carrithers, K. V.; Kelley, W. B.

    1966-01-01

    Metal Y-tube simultaneously directs argon streams over weld areas on both sides of tubes being joined along a line on their outer periphery. The device is advanced along the junction in step with the welding operation.

  3. Inert Welding/Brazing Gas Filters and Dryers

    NASA Technical Reports Server (NTRS)

    Goudy, Jerry

    2009-01-01

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

  4. 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.

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

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

  6. 33 CFR 157.164 - Use of inert gas system.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

  7. 33 CFR 157.164 - Use of inert gas system.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

  8. Condensation of liquid metals under low pressures

    SciTech Connect

    Elafify, M.M.

    1988-01-01

    The Direct Simulation Monte Carlo (DSMC) method is used to study one-dimensional condensation phenomena for a pure vapor or vapor/gas mixture. The results are fitted to an interpolation formula describing the condensation mass flux to provide a usable engineering correlation. For pure vapor, the DSMC results are compared with the available experimental data for condensation of mercury under low pressure. Results are compared also with some of the theoretical models. The comparison shows that the DSMC method is able to detect the qualitative behavior of the condensation mass flux, although it overestimates the mass flux by 20-30%. Compared with other introduced theoretical models, the DSMC method has the most-consistent representation of the qualitative behavior of the condensation mass flux. The method was also used to represent condensation in the presence of a noncondensable gas. A formal proof for choosing collision partners was introduced and applied in the case of condensation in the presence of a noncondensable gas. The method is applied to condensation of mercury in the presence of different monatomic noncondensable gases at different partial pressures.

  9. Condensation model for the ESBWR passive condensers

    SciTech Connect

    Revankar, S. T.; Zhou, W.; Wolf, B.; Oh, S.

    2012-07-01

    In the General Electric's Economic simplified boiling water reactor (GE-ESBWR) the passive containment cooling system (PCCS) plays a major role in containment pressure control in case of an loss of coolant accident. The PCCS condenser must be able to remove sufficient energy from the reactor containment to prevent containment from exceeding its design pressure following a design basis accident. There are three PCCS condensation modes depending on the containment pressurization due to coolant discharge; complete condensation, cyclic venting and flow through mode. The present work reviews the models and presents model predictive capability along with comparison with existing data from separate effects test. The condensation models in thermal hydraulics code RELAP5 are also assessed to examine its application to various flow modes of condensation. The default model in the code predicts complete condensation well, and basically is Nusselt solution. The UCB model predicts through flow well. None of condensation model in RELAP5 predict complete condensation, cyclic venting, and through flow condensation consistently. New condensation correlations are given that accurately predict all three modes of PCCS condensation. (authors)

  10. Bose-Einstein condensation of lithium

    NASA Astrophysics Data System (ADS)

    Sackett, C. A.; Bradley, C. C.; Welling, M.; Hulet, R. G.

    1997-10-01

    Bose-Einstein condensation of 7Li has been studied in a magnetically trapped gas. Many-body quantum theory predicts that the occupation number of the condensate is limited to about 1400 atoms because of the effectively attractive interactions between 7Li atoms. Using a versitile phase-contrast imaging technique, we experimentally observe the condensate number to be consistent with this limit. We discuss our measurements, the current theoretical understanding of BEC in a gas with attractive interactions, and future experiments we hope to perform.

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

    DOEpatents

    Ray, Siba P.; Liu, Xinghua; Weirauch, Douglas A.; DiMilia, Robert A.; Dynys, Joseph M.; Phelps, Frankie E.; LaCamera, Alfred F.

    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.

  12. Electrolytic production of high purity aluminum using inert anodes

    DOEpatents

    Ray, Siba P.; Liu, Xinghua; Weirauch, Jr., Douglas A.

    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.

  13. 46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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

  14. 46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

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

  15. 46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

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

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

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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

  17. Neutrinos from Inert Doublet dark matter

    NASA Astrophysics Data System (ADS)

    Andreas, Sarah; Tytgat, Michel H. G.; Swillens, Quentin

    2009-04-01

    We investigate the signatures of neutrinos produced in the annihilation of WIMP dark matter in the Earth, the Sun and at the Galactic centre within the framework of the Inert Doublet Model and extensions. We consider a dark matter candidate, that we take to be one of the neutral components of an extra Higgs doublet, in three distinct mass ranges, which have all been shown previously to be consistent with both WMAP abundance and direct detection experiments exclusion limits. Specifically, we consider a light WIMP with mass between 4 and 8 GeV (low), a WIMP with mass around 60-70 GeV (middle) and a heavy WIMP with mass above 500 GeV (high). In the first case, we show that capture in the Sun may be constrained using Super-Kamiokande data. In the last two cases, we argue that indirect detection through neutrinos is challenging but not altogether excluded. For middle masses, we try to make the most benefit of the proximity of the so-called 'iron resonance' that might enhance the capture of the dark matter candidate by the Earth. The signal from the Earth is further enhanced if light right-handed Majorana neutrinos are introduced, in which case the scalar dark matter candidate may annihilate into pairs of mono-energetic neutrinos. In the case of high masses, detection of neutrinos from the Galactic centre might be possible, provided the dark matter abundance is substantially boosted.

  18. Direct condensation refrigerant recovery and restoration system

    SciTech Connect

    Grant, D.C.H.

    1992-03-10

    This patent describes a refrigerant recovery and purification system for removing gaseous refrigerant from a disabled refrigeration unit, cleaning the refrigerant of contaminants, and converting the gaseous refrigerant to a liquid state for storage. It comprises a low pressure inlet section; a high pressure storage section; the low pressure inlet section comprising: an oil and refrigerant gas separator, including a separated oil removal means, first conduit means for connecting an inlet of the separator to the disabled refrigerant unit, a slack-sided accumulator, second conduit means connecting the separator to the slack-sided accumulator, a reclaim condenser, third conduit means connecting the separator and the reclaim condenser in series, an evaporator coil in the reclaim condenser connectable to a conventional operating refrigeration system for receiving a liquid refrigerant under pressure for expansion therein, the evaporator coil forming a condensing surface for condensing the refrigerant gas at near atmospheric pressure in the condenser, a liquid receiver, a reclaimed refrigerant storage tank, fourth conduit means further connecting the liquid receiver in series with the reclaim condenser, downstream thereof, means between the reclaim condenser and the liquid receiver.

  19. 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.

  20. 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.

  1. Agglomeration of Ni-nanoparticles in the gas phase under gravity and microgravity conditions

    NASA Astrophysics Data System (ADS)

    Lösch, S.; Iles, G. N.; Schmitz, B.; Günther, B. H.

    2011-12-01

    The agglomeration of metallic nanoparticles can be performed using the well-known inert gas condensation process. Unfortunately, thermal effects such as convection are created by the heating source and as a result the turbulent aerosol avoids ideal conditions. In addition, the sedimentation of large particles and/or agglomerates influences the self-assembly of particles. These negative effects can be eliminated by using microgravity conditions. Here we present the results of the agglomeration of nanoscale Ni-particles under gravity and microgravity conditions, the latter provided by adapted microgravity platforms namely the European sounding rocket MAXUS 8 and the European Parabolic Flight aircraft, Airbus A300 Zero-G.

  2. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

  4. 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. ); Peterson, R.D.; Richards, N.E.; Tabereaux, A.T. . 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.

  5. Condensed Matter Nuclear Science

    NASA Astrophysics Data System (ADS)

    Biberian, Jean-Paul

    2006-02-01

    1. General. A tribute to gene Mallove - the "Genie" reactor / K. Wallace and R. Stringham. An update of LENR for ICCF-11 (short course, 10/31/04) / E. Storms. New physical effects in metal deuterides / P. L. Hagelstein ... [et al.]. Reproducibility, controllability, and optimization of LENR experiments / D. J. Nagel -- 2. Experiments. Electrochemistry. Evidence of electromagnetic radiation from Ni-H systems / S. Focardi ... [et al.]. Superwave reality / I. Dardik. Excess heat in electrolysis experiments at energetics technologies / I. Dardik ... [et al.]. "Excess heat" during electrolysis in platinum/K[symbol]CO[symbol]/nickel light water system / J. Tian ... [et al.]. Innovative procedure for the, in situ, measurement of the resistive thermal coefficient of H(D)/Pd during electrolysis; cross-comparison of new elements detected in the Th-Hg-Pd-D(H) electrolytic cells / F. Celani ... [et al.]. Emergence of a high-temperature superconductivity in hydrogen cycled Pd compounds as an evidence for superstoihiometric H/D sites / A. Lipson ... [et al.]. Plasma electrolysis. Calorimetry of energy-efficient glow discharge - apparatus design and calibration / T. B. Benson and T. O. Passell. Generation of heat and products during plasma electrolysis / T. Mizuno ... [et al.]. Glow discharge. Excess heat production in Pd/D during periodic pulse discharge current in various conditions / A. B. Karabut. Beam experiments. Accelerator experiments and theoretical models for the electron screening effect in metallic environments / A. Huke, K. Czerski, and P. Heide. Evidence for a target-material dependence of the neutron-proton branching ratio in d+d reactions for deuteron energies below 20keV / A. Huke ... [et al.]. Experiments on condensed matter nuclear events in Kobe University / T. Minari ... [et al.]. Electron screening constraints for the cold fusion / K. Czerski, P. Heide, and A. Huke. Cavitation. Low mass 1.6 MHz sonofusion reactor / R. Stringham. Particle detection. Research into characteristics of X-ray emission laser beams from solidstate cathode medium of high-current glow discharge / A. B. Karabut. Charged particles from Ti and Pd foils / L. Kowalski ... [et al.]. Cr-39 track detectors in cold fusion experiments: review and perspectives / A. S. Roussetski. Energetic particle shower in the vapor from electrolysis / R. A. Oriani and J. C. Fisher. Nuclear reactions produced in an operating electrolysis cell / R. A. Oriani and J. C. Fisher. Evidence of microscopic ball lightning in cold fusion experiments / E. H. Lewis. Neutron emission from D[symbol] gas in magnetic fields under low temperature / T. Mizuno ... [et al.]. Energetic charged particle emission from hydrogen-loaded Pd and Ti cathodes and its enhancement by He-4 implantation / A. G. Lipson ... [et al.]. H-D permeation. Observation of nuclear transmutation reactions induced by D[symbol] gas permeation through Pd complexes / Y. Iwamura ... [et al.]. Deuterium (hydrogen) flux permeating through palladium and condensed matter nuclear science / Q. M. Wei ... [et al.]. Triggering. Precursors and the fusion reactions in polarized Pd/D-D[symbol]O system: effect of an external electric field / S. Szpak, P. A. Mosier-Boss, and F. E. Gordon. Calorimetric and neutron diagnostics of liquids during laser irradiation / Yu. N. Bazhutov ... [et al.]. Anomalous neutron capture and plastic deformation of Cu and Pd cathodes during electrolysis in a weak thermalized neutron field: evidence of nuclei-lattice exchange / A. G. Lipson and G. H. Miley. H-D loading. An overview of experimental studies on H/Pd over-loading with thin Pd wires and different electrolytic solutions / A. Spallone ... [et al.] -- 3. Transmutations. Photon and particle emission, heat production, and surface transformation in Ni-H system / E. Campari ... [et al.]. Surface analysis of hydrogen-loaded nickel alloys / E. Campari ... [et al.]. Low-energy nuclear reactions and the leptonic monopole / G. Lochak and L. Urutskoev. Results of analysis of Ti foil after glow discharge with deuterium / I. B. Savvatimova and D. V. Gavritenkov. Enhancement mechanisms of low-energy nuclear reactions / F. A. Gareev, I. E. Zhidkova, and Y. L. Ratis. Co-deposition of palladium with hydrogen isotopes / J. Dash and A. Ambadkar. Variation of the concentration of isotopes copper and zinc in human plasmas of patients affected by cancer / A. Triassi. Transmutation of metal at low energy in a confined plasma in water / D. Cirillo and V. Iorio. The conditions and realization of self-similar Coulomb collapse of condensed target and low-energy laboratory nucleosynthesis / S. V. Adamenko and V. I. Vysotskii. The spatial structure of water and the problem of controlled low-energy nuclear reactions in water matrix / V. I. Vysotskii and A. A. Kornilova. Experiments on controlled decontamination of water mixture of longlived active isotopes in biological cells / V. I. Vysotskii. Assessment of the biological effects of "strange" radiation / E. A. Pryakhin ... [et al.]. Possible nuclear transmutation of nitrogen in the earth's atmosphere / M. Fukuhara. Evidences on the occurrence of LENR-type processes in alchemical transmutations / J. Pérez-Pariente. History of the discovery of transmutation at Texas A&M University / J. O.-M. Bockris -- 4. Theory. Quantum electrodynamics. Concerning the modeling of systems in terms of quantum electro dynamics: the special case of "cold fusion" / M. Abyaneh ... [et al.]. Screening. Theoretical model of the probability of fusion between deuterons within deformed lattices with microcracks at room temperature / F. Fulvio. Resonant tunnelling. Effective interaction potential in the deuterium plasma and multiple resonance scattering / T. Toimela. Multiple scattering theory and condensed matter nuclear science - "super-absorption" in a crystal latice / X. Z. Li ... [et al.]. Ion band states. Framework for understanding LENR processes, using conventional condensed matter physics / S. R. Chubb. I. Bloch ions / T. A. Chubb. II. Inhibited diffusion driven surface transmutations / T. A. Chubb. III. Bloch nuclides, Iwamura transmutations, and Oriani showers / T. A. Chubb. Bose-Einstein condensate. Theoretical study of nuclear reactions induced by Bose-Einstein condensation in Pd / K.-I. Tsuchiya and H. Okumura. Proposal for new experimental tests of the Bose-Einstein condensation mechanism for low-energy nuclear reaction and transmutation processes in deuterium loaded micro- and nano-scale cavities / Y. E. Kim ... [et al.]. Mixtures of charged bosons confined in harmonic traps and Bose-Einstein condensation mechanism for low-energy nuclear reactions and transmutation processes in condensed matters / Y. E. Kim and A. L. Zubarev. Alternative interpretation of low-energy nuclear reaction processes with deuterated metals based on the Bose-Einstein condensation mechanism / Y. E. Kim and T. O. Passell. Multi-body fusion. [symbol]He/[symbol]He production ratios by tetrahedral symmetric condensation / A. Takahashi. Phonon coupling. Phonon-exchange models: some new results / P. L. Hagelstein. Neutron clusters. Cold fusion phenomenon and solid state nuclear physics / H. Kozima. Neutrinos, magnetic monopoles. Neutrino-driven nuclear reactions of cold fusion and transmutation / V. Filimonov. Light monopoles theory: an overview of their effects in physics, chemistry, biology, and nuclear science (weak interactions) / G. Lochak. Electrons clusters and magnetic monopoles / M. Rambaut. Others. Effects of atomic electrons on nuclear stability and radioactive decay / D. V. Filippov, L. I. Urutskoev, and A. A. Rukhadze. Search for erzion nuclear catalysis chains from cosmic ray erzions stopping in organic scintillator / Yu. N. Bazhutov and E. V. Pletnikov. Low-energy nuclear reactions resulting as picometer interactions with similarity to K-shell electron capture / H. Hora ... [et al.] -- 5. Other topics. On the possible magnetic mechanism of shortening the runaway of RBMK-1000 reactor at Chernobyl Nuclear Power Plant / D. V. Filippov ... [et al.]. Cold fusion in the context of a scientific revolution in physics: history and economic ramifications / E. Lewis. The nucleovoltaic cell / D. D. Moon. Introducing the book "Cold Fusion and the Future" / J. Rothwell. Recent cold fusion claims: are they valid? / L. Kowalski. History of attempts to publish a paper / L. Kowalski.

  6. Analytical Treatment of Normal Condensation Shock

    NASA Technical Reports Server (NTRS)

    Heybey

    1947-01-01

    The condensation of water vapor in an air consequences: acquisition of heat (liberated heat vaporization; loss of mass on the part of the flowing gas (water vapor is converted to liquid); change in the specific gas constants and of the ratio k of the specific heats (caused by change of gas composition). A discontinuous change of state is therefore connected with the condensation; schlieren photographs of supersonic flows in two-dimensional Laval nozzles show two intersecting oblique shock fronts that in the case of high humidities may merge near the point of intersection into one normal shock front.

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

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

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

  8. 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.

  9. Condensates in Jovian Atmospheres

    NASA Technical Reports Server (NTRS)

    West, R.

    1999-01-01

    Thermochemical equilibrium theory which starts with temperature/pressure profiles, compositional information and thermodynamic data for condensable species in the jovian planet atmospheres predicts layers of condensate clouds in the upper troposphere.

  10. Recovering condensables from a hydrocarbon gaseous stream

    SciTech Connect

    Fabbri, C.; Bellitto, G.; Failla, B.; La Mantia, G.

    1984-12-04

    The gaseous mixture to be split is dehydrated and condensed under a high pressure by sending the gases, separated in a first separator, to the first stage of an expansion turbine and the condensates are sent to a fractionating column, the gases exiting the first stage of the turbine are mixed with the gases exiting a second separator, said mixture being sent to a third separator the bottom liquid whereof is sent to the column, and the separated gas is mixed with the head gas of the column, whereafter it is cooled and sent to a medium-pressure fourth separator. The gas coming from the latter separator feeds the second stage of the turbine while the condensate is admixed with the gas discharged from the second stage and sent to an ultimate low-pressure separator wherefrom the condensate is sent to the column head and the residual gas is cooled and compressed, the condensates being recovered from the bottom of the column.

  11. Non-inert refrigerant study for automotive applications. Final report, March--December 1990

    SciTech Connect

    Dieckmann, J.T.; Bentley, J.; Varone, A.

    1991-11-01

    Alternatives to CFC-12 for automobile air conditioning were examined. The list of candidate fluids included flammable as well as non-flammable substances. HFC-134a was taken as the baseline alternative given current industry plans to convert automobile air conditioning systems to this fluid over the next several years. Three flammable (non-inert) altemative refrigerants -- BFC-152a, HC-290 (propane) and HC-270 (cyclopropane) were identified. Air conditioning cycle efficiency, ozone depletion potential, and global warming impacts of these three fluids and HFC-134a were compared, with the three non-inert fluids all having higher COP and lower global warming impact. The ozone depletion potential of each of these fluids is zero. The fire safety implications of the flammable alternatives being used in otherwise conventional automobile air conditioning systems were examined in preliminary fashion. The results, which are subject to more extensive verification indicate that the additional passenger compartment fire risk would be very small, while the incidence of engine compartment fires would increase modestly. The engine compartment fire hazard could be minimized by modest design changes to reduce the occurrence of ignition sources and condenser punctures in front end collisions.

  12. Vortices and turbulence in trapped atomic condensates

    PubMed Central

    White, Angela C.; Anderson, Brian P.; Bagnato, Vanderlei S.

    2014-01-01

    After more than a decade of experiments generating and studying the physics of quantized vortices in atomic gas Bose–Einstein condensates, research is beginning to focus on the roles of vortices in quantum turbulence, as well as other measures of quantum turbulence in atomic condensates. Such research directions have the potential to uncover new insights into quantum turbulence, vortices, and superfluidity and also explore the similarities and differences between quantum and classical turbulence in entirely new settings. Here we present a critical assessment of theoretical and experimental studies in this emerging field of quantum turbulence in atomic condensates. PMID:24704880

  13. Heterogeneous Vapor Condensation in Boundary Layers

    SciTech Connect

    Bonilla, L. L.; Carpio, A.; Neu, J. C.

    2008-09-01

    We consider heterogeneous condensation of vapors mixed with a carrier gas in stagnation point boundary layer flow near a cold wall in the presence of solid particles much larger than the mean free path of vapor particles. The supersaturated vapor condenses on the particles by diffusion, particles and droplets are thermophoretically attracted to the wall. We sketch three asymptotic theories of the condensation process, calculate the flow-induced shift in the dew point interface, vapor density profile and deposition rates at the wall, and compare them to direct numerical simulation.

  14. Electrochemical polishing of hydrogen sulfide from coal synthesis gas

    SciTech Connect

    Gleason, E.F.; Winnick, J.

    1995-11-01

    An advanced process has been developed for the separation of H{sub 2}S from coal gasification product streams through an electrochemical membrane. This technology is developed for use in coal gasification facilities providing fuel for cogeneration coal fired electrical power facilities and Molten Carbonate Fuel Cell electrical power facilities. H{sub 2}S is removed from the syn-gas by reduction to the sulfide ion and H at the cathode. The sulfide ion migrates to the anode through a molten salt electrolyte suspended in an inert ceramic matrix. Once at the anode it is oxidized to elemental sulfur and swept away for condensation in an inert gas stream. The syn-gas is enriched with the H{sub 2}. Order-of-magnitude reductions in H{sub 2}S have been repeatably recorded (100 ppm to 10 ppm H{sub 2}S) on a single pass through the cell. This process allows removal of H{sub 2}S without cooling the gas stream and with negligible pressure loss through the separator. Since there are no absorbents used, there is no absorption/regeneration step as with conventional technology. Elemental sulfur is produced as a by-product directly, so there is no need for a Claus process for sulfur recovery. This makes the process economically attractive since it is much less equipment intensive than conventional technology.

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

    SciTech Connect

    Ghosh, Somnath; Friedrich, Rainer

    2015-05-15

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

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

    DOEpatents

    Coolidge, Dennis W.; Rinker, Franklin G.

    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.

  17. 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.

  18. Exhaust gas treatment in testing nuclear rocket engines

    NASA Astrophysics Data System (ADS)

    Zweig, Herbert R.; Fischler, Stanley; Wagner, William R.

    1993-01-01

    With the exception of the last test series of the Rover program, Nuclear Furnace 1, test-reactor and rocket engine hydrogen gas exhaust generated during the Rover/NERVA program was released directly to the atmosphere, without removal of the associated fission products and other radioactive debris. Current rules for nuclear facilities (DOE Order 5480.6) are far more protective of the general environment; even with the remoteness of the Nevada Test Site, introduction of potentially hazardous quantities of radioactive waste into the atmosphere must be scrupulously avoided. The Rocketdyne treatment concept features a diffuser to provide altitude simulation and pressure recovery, a series of heat exchangers to gradually cool the exhaust gas stream to 100 K, and an activated charcoal bed for adsorption of inert gases. A hydrogen-gas fed ejector provides auxiliary pumping for startup and shutdown of the engine. Supplemental filtration to remove particulates and condensed phases may be added at appropriate locations in the system. The clean hydrogen may be exhausted to the atmosphere and flared, or the gas may be condensed and stored for reuse in testing. The latter approach totally isolates the working gas from the environment.

  19. 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.

  20. Gas shielding apparatus

    DOEpatents

    Brandt, Daniel

    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.