Sample records for inert gas condensation

  1. Molecular dynamics simulation of pressure dependence of cluster growth in inert gas condensation E. Kesl, A. Kuronen, and K. Nordlund

    E-print Network

    Nordlund, Kai

    Molecular dynamics simulation of pressure dependence of cluster growth in inert gas condensation E of nanoclusters during inert gas condensation has been studied for copper, silver, alumi- num, and platinum, began when Bentley and Henkes in 1961 indepen- dently detected jet-generated clusters of carbon dioxide

  2. 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.

  3. 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

  4. Inert gas: Vapor mixtures in thermoacoustics

    Microsoft Academic Search

    William Victor Slaton

    2001-01-01

    An analytic solution of sound propagation in wet-walled tubes with a temperature gradient will be presented. The tube contains an inert gas-vapor mixture with a thin layer of condensed vapor coating the tube wall. The vapor phase condenses and evaporates from this layer during an acoustic cycle. This phased evaporation and condensation modifies traditional energy density and wave number equations.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. LNG ship tank inert gas generation system

    Microsoft Academic Search

    1974-01-01

    Chicago Bridge and Iron Co.'s new inert-gas system, designed for safely emptying LNG from storage tanks and avoiding potentially explosive gas\\/air mixtures in case of catastrophic ship collision, does not require the usual additional machinery such as an internal-combustion engine and a compressor. The inert-gas system consists of a supply tank for a liquefied inert gas such as nitrogen, an

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

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 false Inert gas system: Controls. 154.904 Section 154.904...Construction and Equipment Atmospheric Control in Cargo Containment Systems § 154.904 Inert gas system: Controls. The inert gas system must...

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

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Inert gas system: Controls. 154.904 Section 154.904...Construction and Equipment Atmospheric Control in Cargo Containment Systems § 154.904 Inert gas system: Controls. The inert gas system must...

  12. 46 CFR 154.904 - Inert gas system: Controls.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 false Inert gas system: Controls. 154.904 Section 154.904...Construction and Equipment Atmospheric Control in Cargo Containment Systems § 154.904 Inert gas system: Controls. The inert gas system must...

  13. 46 CFR 147.66 - Inert gas fire extinguishing systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...gas fire extinguishing systems. 147.66 Section...DANGEROUS CARGOES HAZARDOUS SHIPS' STORES Stowage...gas fire extinguishing systems. (a) Inert gas...cylinders and discharge piping for fixed inert gas fire extinguishing systems must be renewed or...

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

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...gas fire extinguishing systems. 147.66 Section...DANGEROUS CARGOES HAZARDOUS SHIPS' STORES Stowage...gas fire extinguishing systems. (a) Inert gas...cylinders and discharge piping for fixed inert gas fire extinguishing systems must be renewed or...

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

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...gas fire extinguishing systems. 147.66 Section...DANGEROUS CARGOES HAZARDOUS SHIPS' STORES Stowage...gas fire extinguishing systems. (a) Inert gas...cylinders and discharge piping for fixed inert gas fire extinguishing systems must be renewed or...

  16. 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.

  17. Gear Lubrication in Inert Gas Atmospheres

    Microsoft Academic Search

    B. B. Baber; C. W. Lawler; H. R. Smith; G. A. Beane; P. M. Ku

    1960-01-01

    An investigation was made of the effect of inert gas atmospheres on the gear load-carrying capacity of lubricants. The experiments were performed in two types of gear test machines, using case-hardened AMS-6260 steel test gears. It was found that two mineral oils (a solvent-extracted turbine oil base stock and a USP grade white mineral oil), as well as the same

  18. Positron-inert gas differential elastic scattering

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

  19. 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.

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

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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

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

    Code of Federal Regulations, 2014 CFR

    2014-10-01

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

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

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  3. 46 CFR 154.903 - Inert gas systems: General.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

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

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

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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

  5. 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...

  6. Pulsed laser deposition of metals in various inert gas atmospheres

    NASA Astrophysics Data System (ADS)

    Scharf, T.; Faupel, J.; Sturm, K.; Krebs, H.-U.

    The changes in the properties of laser deposited metal thin films were investigated in different inert gas atmospheres (He, Ne, Ar and Xe). With increasing inert gas pressure, the reduction of particle energy is accompanied by a strong increase of the deposition rate (especially in He atmosphere), a transition from compressive to tensile stress, and changes in structure and texture. This is explained by a reduction of surface mobility of the deposited particles, a decrease of implantation, resputtering and shot-peening effects. At high gas pressures, deposition conditions similar to sputtering or even thermal deposition are obtained.

  7. 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.

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

    PubMed

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

    2014-12-01

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

  9. 46 CFR 153.462 - Static discharges from inert gas systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Static discharges from inert gas systems. ...Or Combustible Cargoes § 153.462 Static discharges from inert gas systems. ...flammable or combustible cargo must not create static arcing as the inert gas is injected...

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

    SciTech Connect

    Maicu, Marina, E-mail: marina.maicu@fep.fraunhofer.de; Glöß, Daniel; Frach, Peter [Fraunhofer Institut für Elektronenstrahl und Plasmatechnik, FEP, Winterbergstraße 28, 01277 Dresden (Germany); Schmittgens, Ralph; Gerlach, Gerald [Institut für Festkörperelektronik, IFE, TU Dresden, Helmholtz Straße 18, 01069 Dresden (Germany); Hecker, Dominic [Fraunhofer Institut für Elektronenstrahl und Plasmatechnik, FEP, Winterbergstraße 28, 01277 Dresden, Germany and Institut für Festkörperelektronik, IFE, TU Dresden, Helmholtz Straße 18, 01069 Dresden (Germany)

    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. Condensation in gas transmission pipelines

    Microsoft Academic Search

    J. A. Schouten; R. Janssen-van Rosmalen; J. P. J. Michels

    2005-01-01

    Several pressure and temperature reductions occur along gas transmission lines. Since the pressure and temperature conditions of the natural gas in the pipeline are often close to the dew point curve, liquid dropout can occur. Injection of hydrogen into the natural gas will change the phase envelope and thus the liquid dropout. This condensation of the heavy hydrocarbons requires continuous

  12. Odorization of inert gas for occupational safety: psychophysical considerations.

    PubMed

    Cain, W S; Leaderer, B P; Cannon, L; Tosun, T; Ismail, H

    1987-01-01

    Odorization of inert gas can serve to warn workers in an enclosed space about gas leaking into the space. This psychophysical investigation, performed under conditions of directed attention, examined two candidates for possible odorization of argon:pyridine and cis-3-hexen-1-ol. Detection thresholds for pyridine and cis-3-hexen-1-ol in argon were 106 ppb and 19 ppb, respectively. Practice over four days yielded modest improvement in the detection of both odorants. For cis-3-hexen-1-ol, smokers had marginally lower thresholds than nonsmokers and older participants had slightly higher thresholds than younger participants. Gender, smoking status and age had no reliable influence on threshold for pyridine. This outcome indicated desirable perceptual stability for pyridine. Additional experiments dealt with the perceived intensity of pyridine and cis-3-hexen-1-ol over time in the realistic setting of an environmental chamber. Visitors to the chamber and occupants in the chamber assessed perceived magnitude at 5-min intervals for up to 60 min during injections of odorized argon into the chamber. Participants could gauge and track the concentration of pyridine much better than that of cis-3-hexen-1-ol. This held true for occupants almost to the same degree as visitors, though occupants inevitably exhibited some olfactory adaptation. Hence, the suprathreshold measurements also gave strong relative endorsement to pyridine. Calculations based on the experimental results indicated that odorization of the inert gas stream with 3 to 10 ppm (v/v) pyridine should suffice to warn occupants or visitors of an argon buildup of any severity. Field studies should permit a definitive judgment of the best concentration to use in practice. PMID:3031973

  13. Evacuation of a residual oil pipeline by inert gas displacement

    SciTech Connect

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

    1987-02-01

    This paper describes an analysis developed to model the inert gas displacement process for evacuating a high-pour-point oil from a long pipeline. The governing equations were derived from the basic conservation equations for mass, momentum, and energy. The resultant computer program accounts for such effects as pipeline elevation changes, laminar and turbulent oil flow, temperature-dependent oil viscosity, and heat loss from the oil to the ground. Results of computations for an 84-mile (135-km) residual oil pipeline operated by the Pennsylvania Power and Light Co. are presented and compared with pressure measurements obtained during a trial purge of the system. Calculations show that the minimum N/sub 2/ volume required for a successful pipeline evacuation increases considerably with increased delay time. In addition, theoretical results indicate that for this case, the pipeline purge operation must begin within 20 hours of a shutdown to avoid evacuation difficulties.

  14. A high-temperature inert gas fusion apparatus.

    PubMed

    Mosen, A W; Kelley, R E; Mitchell, H P

    1966-03-01

    A high-temperature inert gas fusion apparatus capable of operating at crucible temperatures as high as 3,100 degrees is described. While this apparatus has been used primarily for the determination of oxygen in pyrolytic carbon-coated uranium carbide particles, its usefulness is not limited to this type of material. It can be generally applied to the determination of oxygen and nitrogen in metals, alloys and other materials amenable to analysis by vacuum-fusion techniques. Analytical results obtained on steel and uranium carbide samples are presented. The apparatus, in its present form, has been in daily use for nearly 2 years. Down time during this period has been negligible. A total of 20 samples can be run in duplicate in an 8-hr shift. PMID:18959890

  15. Design of a diesel exhaust-gas purification system for inert-gas drilling

    SciTech Connect

    Caskey, B.C.

    1982-01-01

    To combat the serious oxygen corrosion of drill pipe when a low density drilling fluid (air or mist) is used in geothermal drilling, a system has been designed that produces an inert gas (essentially nitrogen) to be substituted for air. The system fits on three flatbed trailers, is roadable and produces 2000 scfm of gas. The projected cost for gas is slightly less than $2.00 per thousand standard cubic feet.

  16. 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.

  17. 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.

  18. 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.

  19. Investigation on the Oscillating Gas Flow Along AN Inertance Tube by Experimental and Cfd Methods

    Microsoft Academic Search

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

    2010-01-01

    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

  20. Isothermic adsorption of heavy inert gas atoms on graphite surfaces at low pressures

    NASA Astrophysics Data System (ADS)

    Nymand, Gustav Uffe; Nyeland, Carl

    1999-04-01

    Following a recently suggested electron gas density method for intermolecular potentials between inert gas atoms and solid surfaces, potentials have been calculated for inert gas atoms interacting with carbon atoms of the surface of graphite. Isothermic adsorption coefficients were then calculated as virial coefficients using atom-atom addition potentials. The results obtained were compared with experimental findings for isothermic adsorption finding good agreement for both values and temperature dependencies.

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

    NASA Technical Reports Server (NTRS)

    Rawlin, V. K.

    1982-01-01

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

  2. Investigation on the Oscillating Gas Flow Along AN Inertance Tube by Experimental and Cfd Methods

    NASA Astrophysics Data System (ADS)

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

    2010-04-01

    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.

  3. Gas condensate damage in hydraulically fractured wells

    E-print Network

    Reza, Rostami Ravari

    2004-11-15

    -vaporize. This region is called the retrograde condensation zone and reservoirs experiencing this phenomenon are known as gas condensate reservoirs 1. 1.2.1 Gas condensate reservoir fluid modeling In compositional simulation of oil and gas reservoirs... Ayoola Adeyeye, this subject was studied when the effects of reservoir depletion were minimized by introduction of an injector well with fluid composition the same as the original reservoir fluid. He also used an infinite conductivity hydraulic...

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

    DOEpatents

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

    1997-01-01

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

  5. 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.

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

    NASA Technical Reports Server (NTRS)

    1966-01-01

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

  7. 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

  8. Reactive gas condensation synthesis of aluminum nitride nanoparticles.

    PubMed

    Baker, Colin C; Ceylan, Abdullah; Shah, S Ismat

    2006-01-01

    Aluminum Nitride (AIN) nanoparticles were synthesized using a Reactive Gas Condensation (RGC) technique in which a mixture of ammonia (NH3) and nitrogen (N2) gases were used for the nitridation of aluminum. NH3 served as the reactive gas, while N2 served as both a carrier gas and the inert source for particle condensation. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses revealed that at reactive gas compositions greater than 10% NH3 in N2, samples were composed entirely of hexagonal AIN nanoparticles. Electron diffraction patterns showed single crystal hexagonal AIN structure. The particle size was controlled by varying the pressure of the gas mixture. AIN nanoparticles were dispersed in a liquid matrix to enhance thermal conductivity. Results showed that a minimal addition of AIN increased the thermal conductivity of hydrocarbon pump oil by approximately 27%. The thermal conductivity became constant after reaching a maximum above 0.01 wt% AIN. Temporal stability of AIN was studied by XRD. Samples exposed to air for extended periods of time and analyzed by XRD show no degradation of crystalline AIN nanoparticles. PMID:16573086

  9. 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.

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

    NASA Astrophysics Data System (ADS)

    Zhou, X. W.; Wadley, H. N. G.

    2001-10-01

    Control of interfacial roughness and chemical mixing is critical in nanomaterials. For example, multilayers composed of ˜20 Å conductive layer sandwiched between two ˜50 Å ferromagnetic layers can exhibit giant magnetoresistance (GMR). This property has caused a tremendous recent increase in hard disk storage capacity, and can potentially result in a new generation of nonvolatile magnetic random access memories. It has been established that good GMR properties can be obtained when the interfacial roughness and interlayer mixing of these multilayers are low. However, flat interfaces in nanoscale multilayers are not thermodynamically stable, and cannot be obtained using thermal energy deposition processes such as molecular-beam epitaxy. Hyperthermal energy sputter deposition techniques using either plasma or ion-beam gun are able to create nonequilibrium flat interfaces, and have been shown to produce better GMR multilayers. In these processes, however, inert gas ions or neutrals with energies between 50 and 200 eV can impact the growth surface. This may be a major source for interlayer mixing. By using a molecular dynamics technique and a reduced order model, the composition profile across the thickness of multiply repeated Ni/Cu/Ni multilayers has been calculated as a function of the energy and the relative flux of the inert gas ions or neutrals as well as the layer thickness. The results indicate that the 50-200 eV inert gas impact caused atomic exchange between adjacent atomic layers near the surface. The probability of exchange increased with impact energy, but decreased with the number of overlayers. The exchange between Ni overlayer and Cu underlayer atoms was much more significant than that between Cu overlayer and Ni underlayer atoms. As a result, the Ni on Cu interfaces were much more diffuse than the Cu on Ni interfaces, in good agreement with experiments. At very high inert gas flux and impact energy, an increased probability for the underlying Cu atoms to be exchanged to the surface resulted in significant Cu surface segregation.

  11. Stabilization of liquified-inert-gas jets for laser-plasma generation

    Microsoft Academic Search

    B. A. M. Hansson; M. Berglund; O. Hemberg; H. M. Hertz

    2004-01-01

    We investigate the hydrodynamic properties of liquified-inert-gas jets in a vacuum with a special emphasis on their stability. Such jets have applications as targets for laser-plasma generation of soft-x-ray and extreme-ultraviolet (EUV) radiation. An important example is the liquid-xenon-jet laser-plasma source, one of the source candidates for EUV lithography. A simple hydrodynamic model in not sufficient to explain experimental observations

  12. Stabilization of liquified-inert-gas jets for laser–plasma generation

    Microsoft Academic Search

    B. A. M. Hansson; M. Berglund; O. Hemberg; H. M. Hertz

    2004-01-01

    We investigate the hydrodynamic properties of liquified-inert-gas jets in a vacuum with a special emphasis on their stability. Such jets have applications as targets for laser–plasma generation of soft-x-ray and extreme-ultraviolet (EUV) radiation. An important example is the liquid-xenon-jet laser-plasma source, one of the source candidates for EUV lithography. A simple hydrodynamic model in not sufficient to explain experimental observations

  13. 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

  14. 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

  15. Gas condensate damage in hydraulically fractured wells 

    E-print Network

    Adeyeye, Adedeji Ayoola

    2004-09-30

    This project is a research into the effect of gas condensate damage in hydraulically fractured wells. It is the result of a problem encountered in producing a low permeability formation from a well in South Texas owned by the El Paso Production...

  16. The diffusion of oxygen, carbon dioxide, and inert gas in flowing blood.

    PubMed

    Spaeth, E E; Friedlander, S K

    1967-11-01

    Measurements were made of exchange rates of oxygen, carbon dioxide, and krypton-85 with blood at 37.5 degrees C. Gas transfer took place across a 1 mil silicone rubber membrane. The blood was in a rotating disk boundary layer flow, and the controlling resistance to transfer was the concentration boundary layer. Measured rates were compared with rates predicted from the equation of convective diffusion using velocities derived from the Navier-Stokes equations and diffusivities calculated from the theory for conduction in a heterogeneous medium. The measured absorption rate of krypton-85 was closely predicted by this model. Significant deposition of material onto the membrane surface, resulting in an increased transfer resistance, occurred in one experiment with blood previously used in a nonmembrane type artificial lung. The desorption rate of oxygen from blood at low P(o2)(1) was up to four times the corresponding transfer rate of inert gas. This effect is described somewhat conservatively by a local equilibrium form of the convective diffusion equation. The carbon dioxide transfer rate in blood near venous conditions was about twice that of inert gas, a rate significantly greater than predicted by the local equilibrium theory. It should be possible to apply these theoretical methods to predict exchange rates with blood flowing in systems of other geometries. PMID:19211000

  17. Optimization of condensing gas drive 

    E-print Network

    Lofton, Larry Keith

    1977-01-01

    when the displacing gas broke through the bottom of the sand pack. Freon gas was injected into the sand pack at 33 psia and 54 psia. Constant decane withdrawal rates for each injection pressure were 0. 5 and 1. 0 times the gravity drainage reference.... , Hall, H. N. , Bridges, P. M. and HorseN R. A. G "An Experimental and Theoretical Investiga- tion of Gravity Drainage performance, " Trans. , AINE (1951) 192-285. 5. Breitenbach, E. A. , Thurnau, D. H. , and Van Poolen, H. K. : "The Fluid Flow...

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

    NASA Astrophysics Data System (ADS)

    Sun, J.; Longtin, J. P.

    2001-06-01

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

  19. 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.

  20. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  2. Analysis of condensate banking dynamics in a gas condensate reservoir under different injection schemes

    E-print Network

    Sandoval Rodriguez, Angelica Patricia

    2002-01-01

    ANALYSIS OF CONDENSATE BANKING DYNAMICS IN A GAS CONDENSATE RESERVOIR UNDER DIFFERENT INJECTION SCHEMES A Thesis by ANGELICA PATRICIA SANDOVAL RODRIGUEZ Submitted to the Office of Graduate Studies of Texas A&M University in partial... fulfillment of the requirements for the degree of MASTER OF SCIENCE August 2002 Major Subject: Petroleum Engineering ANALYSIS OF CONDENSATE BANKING DYNAMICS IN A GAS CONDENSATE RESERVOIR UNDER DIFFERENT INJECTION SCHEMES A Thesis by ANGELICA PATRICIA...

  3. Buffer-Gas Cooled Bose-Einstein Condensate

    E-print Network

    Ketterle, Wolfgang

    We report the creation of a Bose-Einstein condensate using buffer-gas cooling, the first realization of Bose-Einstein condensation using a broadly general method which relies neither on laser cooling nor unique atom-surface ...

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

    SciTech Connect

    Bures, B. L.; Krishnan, M.; Eshaq, Y. [Alameda Applied Sciences Corp. 626 Whitney St., San Leandro, CA (United States)

    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.

  5. Artificial neural network modeling of weld joint strength prediction of a pulsed metal inert gas welding process using arc signals

    Microsoft Academic Search

    Sukhomay Pal; Surjya K. Pal; Arun K. Samantaray

    2008-01-01

    This paper addresses the weld joint strength monitoring in pulsed metal inert gas welding (PMIGW) process. Response surface methodology is applied to perform welding experiments. A multilayer neural network model has been developed to predict the ultimate tensile stress (UTS) of welded plates. Six process parameters, namely pulse voltage, back-ground voltage, pulse duration, pulse frequency, wire feed rate and the

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

    Microsoft Academic Search

    N. Luemmen; T. Kraska

    2005-01-01

    A detailed analysis of the coalescence of iron clusters over the course of their growth in an inert-gas atmosphere is presented. The investigation is performed by molecular dynamics simulations, using a recent version of the embedded atom method for iron. For several coalescence events extracted from realistic particle-growth simulations, the change of temperature, the atomic structure, and the morphology are

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

    Microsoft Academic Search

    S. C Juang; Y. S Tarng

    2002-01-01

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

  8. Size-independent fcc-to-icosahedral structural transition in unsupported silver clusters: An electron diffraction study of clusters produced by inert-gas aggregation

    Microsoft Academic Search

    D. Reinhard; B. D. Hall; D. Ugarte; R. Monot

    1997-01-01

    The structure of free silver clusters, produced in an inert-gas-aggregation source and flowing in a molecular beam has been studied by electron diffraction. Large clusters (up to 11 nm in diameter) of both icosahedral and fcc structure are observed. Cluster structure is investigated as a function of evaporation temperature and molecular weight of the inert gas in the source. An

  9. Resonant gas oscillation with evaporation and condensation

    NASA Astrophysics Data System (ADS)

    Inaba, Masashi; Yano, Takeru; Watanabe, Masao; Kobayashi, Kazumichi; Fujikawa, Shigeo

    2012-09-01

    Resonant gas oscillation in a closed tube bounded by an oscillating plate and a vaporliquid interface is theoretically analyzed by applying the asymptotic theory to the ES-BGK Boltzmann equation for the case of M2?Kn?1 and a small evaporation coefficient ? = O(Kn), where M and Kn are the typical Mach number and the Knudsen number, respectively. As a result, we derive a nonlinear integro-differential equation for determining the wave profile with the evaporation and condensation in the form including ?.

  10. The effect of condensate dropout on pressure transient analysis of a high-pressure gas condensate well

    E-print Network

    Briens, Frederic Jean-Louis

    1986-01-01

    the permeability of high-pressure gas condensate wells is proposed: first, a phase behavior study of the reservoir fluid should be performed through the use of the Soave-Redlich-'Kwong equation of state to generate liquid fractions and phase compressibility... Condensate Reser voir Data. . 43 Elf Aquitaine Gas Condensate Reservoir Fluid Composition Elf Aquitaine Gas Condensate Well Production Test Data. Drawdown Test F1 of Elf Aquitaine Gas Condensate Mell 45 46 Drawdown Test F2 of Elf Aquitaine Gas...

  11. Spark gap switch system with condensable dielectric gas

    DOEpatents

    Thayer, III, William J. (Kent, WA)

    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.

  12. Altering Wettability in Gas Condensate Sandstone Reservoirs for Gas Mobillity Improvement

    E-print Network

    Fernandez Martinez, Ruth Gabriela

    2012-07-16

    In gas-condensate reservoirs, production rate starts to decrease when retrograde condensation occurs. As the bottomhole pressure drops below the dewpoint, gascondensate and water buildup impede flow of gas to the surface. To stop the impairment...

  13. 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.

  14. Energy balance in disk and CO2 laser beam inert gas fusion cutting

    NASA Astrophysics Data System (ADS)

    Scintilla, Leonardo Daniele; Tricarico, Luigi; Wetzig, Andreas; Beyer, Eckhard

    2012-03-01

    Experimental, numerical and analytical investigations were performed to give a possible explanation of the differences in cutting quality detected for inert gas laser beam cutting process performed with disk and CO2 laser sources. Cutting experiments were carried out at maximum cutting speed on cold work steel test specimens with different sheet thicknesses. The particular feature of the applied experimental setup was the similar geometry of both the CO2 and the disk laser beam with comparable values of the focus diameter and the Rayleigh length. The thermodynamic analysis was based on experimentally primary losses evaluation by means of polymethylmethacrylate (PMMA) blocks, on numerical computation of conductive power losses and analytical calculation of the remaining terms of energy balance. Energy balance allowed the evaluation of secondary losses and proportion of vaporized kerf volume used for justifying the lower quality of disk laser cuts. The lower proportion of vaporized kerf volume detected for disk laser cuts results in an increased process temperature, thus an increase of viscosity of molten material and the subsequent more difficult ejection of the melted material from the cut kerf.

  15. 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

  16. Multiproperty empirical isotropic interatomic potentials for CH4-inert gas mixtures.

    PubMed

    El-Kader, M S A

    2013-11-01

    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

  17. 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.

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

    PubMed

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

    2013-01-01

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

  19. 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

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

    NASA Astrophysics Data System (ADS)

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

    1996-11-01

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

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

    Microsoft Academic Search

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

    2006-01-01

    Residual strains have been measured in a tungsten inert gas (TIG) butt-welded 2024 aluminum alloy plate using synchrotron\\u000a X-ray diffraction. Novel two-dimensional strain maps spanning the entire plate reveal steep gradients in residual stress and\\u000a provide detailed validation data for finite element (FE) analysis. Two variants of a FE model have been used to predict the\\u000a residual strain distributions, incorporating

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

    Microsoft Academic Search

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

    2006-01-01

    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

  3. Analysis of residual stress in metal-inert-gas-welded Al2024 using neutron and synchrotron X-ray diffraction

    Microsoft Academic Search

    S. Ganguly; V. Stelmukh; L. Edwards; M. E. Fitzpatrick

    2008-01-01

    A combination of neutron and synchrotron X-ray diffraction was used to measure and map the full three-dimensional state of residual stress across the cross-section in coupon samples of metal-inert-gas (MIG)-welded 2024 aluminium alloy. Samples were analysed both as-welded and following a post-welding skim which served to remove the weld flash and reduce the plate thickness. The profile of the residual

  4. 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

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

    PubMed

    Hobbs, Malcolm; Kneller, Wendy

    2015-05-15

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

  6. The effective spectral irradiance of ultra-violet radiations from inert-gas-shielded welding processes in relation to the ARC current density

    E-print Network

    DeVore, Robin Kent

    1973-01-01

    fulfillment of the requirement for the degree of MASTER OF SCIENCE December 1973 Major Subject: Industrial Hygiene THE EFFECTIVE SPECTRAL IRRADIANCE OF ULTRAVIOLET RADIATIONS FROM INERT-GAS-SHIELDED WELDING PROCESSES IN RELATION TO THE ARC CURRENT... DENSITY A Thesis by ROBIN KENT DEVORE Approved as to style and content by: C alarm n of o itte Hea o partment e er Member December 1973 ABSTRACT The Effective Spectral Irradiance of Ultraviolet Radiations from Inert-Gas-Shielded Welding...

  7. Analysis of condensate banking dynamics in a gas condensate reservoir under different injection schemes 

    E-print Network

    Sandoval Rodriguez, Angelica Patricia

    2002-01-01

    If the reservoir pressure falls below the dewpoint pressure when producing a gas condensate reservoir, liquid dropout takes place in the reservoir. Liquid builds up in the near wellbore area causing what is known as a ...

  8. 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.

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  10. Treatability of oil shale gas condensate waste water

    Microsoft Academic Search

    R. S. Lewis; G. D. Rawlings; D. R. Day

    1983-01-01

    Laboratory-scale experiments were conducted with an actual modified in-situ (MIS) gas condensate to assess the performance of steam stripping, of the activated-sludge process, and of activated-carbon adsorption for upgrading the quality of this waste water. Steam-stripping experiments were carried out with a laboratory-scale, packed tower which contacted preheated, raw-gas condensate with low-pressure steam in a countercurrent manner. At a steam\\/liquid

  11. 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.

  12. 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.

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

    DOEpatents

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

    1997-01-01

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

  14. Extreme-Wing Line Broadening and Cs-Inert-Gas Potentials

    Microsoft Academic Search

    R. E. Hedges; D. L. Drummond; Alan Gallagher

    1972-01-01

    The emission profiles of the cesium resonance lines broadened by collisions with inert gases have been measured from about 50-1000 cm-1 from line center. The emission is observed from optically excited Cs in a cell whose temperature is varied from about 300-800°K. By measuring the wing intensity relative to the entire line intensity from optically thin Cs, the profiles can

  15. Electron temperature in heavy inert gas plasmas at low electric fields

    SciTech Connect

    Ivanov, V.A.; Prikhod'ko, A.S.

    1986-10-01

    The variation of Te(E/N) (where Te is the electron temperature) and the electron drift velocity W(E/N) in heavy inert gases is analyzed. Numerical results are presented which show that the forms of Te(E/N) and W(E/N) for low electric fields are determined to a large extent by the degree of ionization. The role of metastable atoms is studied using a xenon plasma with a high degree of ionization as an example; it is assumed that the energy distribution is Maxwellian. 15 references.

  16. Applications of noble gas NMR to condensed matter systems

    Microsoft Academic Search

    C.-H. Tseng; R. W. Mair; G. P. Wong; R. L. Walsworth; S. Patz; D. Williamson; M. D. Hurlimann; L. M. Schwartz; D. G. Cory

    1998-01-01

    The spin-off of laser-polarized noble gases (^3He and ^129Xe) from atomic physics to biomedical imaging has renewed interest in gas-phase NMR and MRI. We are applying noble gas NMR to studies of condensed matter systems such as porous media and liquid xenon. NMR measurements of restricted noble gas diffusion in porous media offer two important advantages over conventional (liquid) NMR

  17. 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. [National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8564 (Japan)

    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.

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

    NASA Astrophysics Data System (ADS)

    Hoshi, Y.; Yoshida, H.

    2009-09-01

    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 ? effect is presumed to be significant, similar to in inert gases.

  19. Alleviation of effective permeability reduction of gas-condensate due to condensate buildup near wellbore

    E-print Network

    Carballo Salas, Jose Gilberto

    2006-04-12

    to be extended in order to have acceleration of production and an increase in the final reserves. A compositional-radial reservoir was simulated with one well in the center of 109 grids. Three gas-condensate fluids with different heptanes plus compositions ( 4, 8...

  20. Simulation of gas condensate reservoir performance

    SciTech Connect

    Coast, K.H.

    1982-01-01

    Generalized phase density and component fugacity equations are presented which represent several of the widely used cubic equations-of-state. A component pseudoization procedure is described which preserves densities and viscosities of the pseudo components and original mixture as functions of pressure and temperature. The full compositional simulation necessary for below-dewpoint cycling is performed for the near-critical condensate using a wide range of component pseudoizations. Results show the well-known necessity of splitting the C7+fraction and indicate a minimum set of about 7 total components necessary for acceptable accuracy. 21 refs.

  1. Reactive Transport Modeling of Acid Gas Generation and Condensation

    SciTech Connect

    G. Zhahg; N. Spycher; E. Sonnenthal; C. Steefel

    2005-01-25

    Pulvirenti et al. (2004) recently conducted a laboratory evaporation/condensation experiment on a synthetic solution of primarily calcium chloride. This solution represents one potential type of evaporated pore water at Yucca Mountain, Nevada, a site proposed for geologic storage of high-level nuclear waste. These authors reported that boiling this solution to near dryness (a concentration factor >75,000 relative to actual pore waters) leads to the generation of acid condensate (pH 4.5) presumably due to volatilization of HCl (and minor HF and/or HNO{sub 3}). To investigate the various processes taking place, including boiling, gas transport, and condensation, their experiment was simulated by modifying an existing multicomponent and multiphase reactive transport code (TOUGHREACT). This code was extended with a Pitzer ion-interaction model to deal with high ionic strength. The model of the experiment was set-up to capture the observed increase in boiling temperature (143 C at {approx}1 bar) resulting from high concentrations of dissolved salts (up to 8 m CaCl{sub 2}). The computed HCI fugacity ({approx} 10{sup -4} bars) generated by boiling under these conditions is not sufficient to lower the pH of the condensate (cooled to 80 and 25 C) down to observed values unless the H{sub 2}O mass fraction in gas is reduced below {approx}10%. This is because the condensate becomes progressively diluted by H{sub 2}O gas condensation. However, when the system is modeled to remove water vapor, the computed pH of instantaneous condensates decreases to {approx}1.7, consistent with the experiment (Figure 1). The results also show that the HCl fugacity increases, and calcite, gypsum, sylvite, halite, MgCl{sub 2}4H{sub 2}O and CaCl{sub 2} precipitate sequentially with increasing concentration factors.

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

    NASA Astrophysics Data System (ADS)

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

    1982-09-01

    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 (ball istic 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 nonreactive, insulative, and nonablative. 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.

  3. Direct-contact steam condensation with simultaneous noncondensable gas absorption

    SciTech Connect

    Bontozoglou, V.; Karabelas, A.J. (Aristotle Univ. of Thessaloniki (Greece))

    1995-02-01

    Experimental results are reported on simultaneous heat transfer and gas dissolution during the direct-contact condensation of steam on water in the presence of CO[sub 2]. A column filled with structured packing is used as condenser with the water in counterflow with the steam/CO[sub 2] mixture. The region along the column where the bulk of condensation takes place is controllable by suitable choice of the steam/water ratio. Measured local heat-transfer coefficients change by roughly an order of magnitude from the bottom to the top of the column. The extent of CO[sub 2] dissolution in the water/condensate under most conditions is unexpectedly high and depends strongly on the exit liquid temperature. A driving force based on the interfacial CO[sub 2] concentration, not the overall concentration difference used in conventional absorption operations, is suggested as more appropriate to describe the phenomenon. The data are complemented with preliminary results from a computational model based on the integration along the column of local heat and mass-transfer rates. Direct-contact condensation of steam on water in the presence of noncondensable gases is encountered in various applications such as power-plant condensers, ocean thermal energy conversion systems, and geothermal installations. It is also relevant to the nuclear industry in certain safety evaluation scenarios. The application motivating this study is the separation of noncondensable gases from high pressure geothermal steam upstream of the turbines.

  4. Pore formation during hybrid laser-tungsten inert gas arc welding of magnesium alloy AZ31B—mechanism and remedy

    Microsoft Academic Search

    Liming Liu; Gang Song; Guoli Liang; Jifeng Wang

    2005-01-01

    One of the major concerns during high speed welding of magnesium alloys is the presence of porosity in the weld metal that can deteriorate mechanical properties. This study seeks to analyze the presence method and quantity of pore during hybrid laser-tungsten inert gas arc (TIG) welding of magnesium alloy AZ31B by radiography, optical microscopy and electron probe microanalysis (EMPA). At

  5. 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.

  6. 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.

  7. Impact of inerts, diluents and trace constituents in natural gas on the natural gas industry and the interstate pipeline grid

    Microsoft Academic Search

    S. Chao; K. Crippen

    1995-01-01

    This report addresses gas quality concerns that have arisen industry-wide. The traditional properties affecting gas quality and interchangeability are the BTU content, relative density (specific gravity), the hydrogen to carbon ratio, and hydrocarbon dew point. These properties are directly related to the major and minor component composition of natural gas. Components that have a bearing on gas quality and interchangeability

  8. Dispersion measurement of inert gases and gas mixtures at 800 nm.

    PubMed

    Börzsönyi, A; Heiner, Z; Kalashnikov, M P; Kovács, A P; Osvay, K

    2008-09-20

    Dispersion of femtosecond laser pulses propagating in Ar, He, Kr, N(2), Ne, Xe, and their mixtures is measured by spectrally and spatially resolved interferometry. By varying the gas pressure in a 4.5 m long tube between 0.05 mbar and ambient pressure, the first, second, and third order phase derivatives of broadband laser pulses are determined at 800 nm under standard conditions. The dispersion of gases and gas mixtures obeys the Lorentz-Lorenz formula with an accuracy of 0.7%. Based on the measured pressure dependent dispersion values in the near infrared and the refractive indices available from the literature for the ultraviolet and visible, a pressure dependent Sellmeier-type formula is fitted for each gas. These common form, two-term dispersion equations provide an accuracy between 4.1x10(-9) (Ne) and 4.3x10(-7) (Xe) for the refractive indices, from UV to near IR. PMID:18806842

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

    SciTech Connect

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

    2005-05-15

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

  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 ?g 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. 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...

  12. 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 ?s, 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.

  13. Modeling of Metal Laser Cutting Processes in Supersonic Jet in Inert Gas

    NASA Astrophysics Data System (ADS)

    Kovalev, O. B.; Orishich, A. M.; Fomin, V. M.; Shulyatev, V. B.

    2002-07-01

    Up-to-date CO2 lasers are widely used in laser treatment of materials (drilling, welting, cutting). Technical achievements of laser methods both in Russia and abroad are limited and have been applied only for some types of ferrous metals until now (iron, steel, stainless steel, electrical steel). A number of works, cannot describe satisfactory the processes of gas-laser metal cutting, and this fact implies consideration of a great number of complex and interrelated processes.

  14. Photodissociation of condensed carbon dioxide below the gas phase thresholds

    Microsoft Academic Search

    J. M. Coquel; L. Siller; J. Wilkes; R. Carrapa; C. L. A. Lamont; T. Almeida Gasche; R. E. Palmer; A. M. C. Moutinho

    1998-01-01

    We have investigated photodesorption from condensed carbon dioxide for photon energies ranging from 13 to 35 eV using synchrotron radiation. We report the desorption of O2+ ions at energies as low as 13 eV, and discuss this behaviour in terms of ion–molecule reactions. The desorbed CO+ ion yield shows resonances at ?15.4 and ?17 eV, below the gas-phase thermodynamic threshold

  15. Hot nanoindentation in inert environments

    E-print Network

    Trenkle, Jonathan C.

    An instrument capable of performing nanoindentation at temperatures up to 500?°C in inert atmospheres, including partial vacuum and gas near atmospheric pressures, is described. Technical issues associated with the technique ...

  16. 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.

  17. 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.

  18. Efficient computation of the compositional model for gas condensate reservoirs

    NASA Astrophysics Data System (ADS)

    Zhou, Jifu; Li, Jiachun; Ye, Jigen

    2000-12-01

    In this paper, a direct method, unsymmetric-pattern multifrontal factorization, for a large sparse system of linear equations is applied in the compositional reservoir model. The good performances of this approach are shown by solving the Poisson equation. And then the numerical module is embedded in the compositional model for simulating X1/5 (3) gas condensate reservoir in KeKeYa gas field, Northwest China. The results of oil/gas reserves, variations of stratum pressure and oil/gas production, etc. are compared with the observation. Good agreement comparable to COMP4 model is achieved, suggesting that the present model is both efficient and powerful in compositional reservoir simulations.

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

  20. Optimizing perforation performance for the Armada gas condensate development

    SciTech Connect

    Bird, K.; Dunmore, S.

    1995-12-31

    The Armada field development will bring onto production three gas condensate discoveries in Quadrants 16 and 22 of the Central Area of the United Kingdom (UK), North Sea. The largest field, Fleming, will be developed concurrently with the other two deeper reservoirs, Drake and Hawkins. Over one trillion cubic feet of recoverable gas are present. Peak platform production rates of 450 MMscf/d will initially be obtained from eight wells. The degree of underbalance has a significant impact on well performance and perforation geometry. This paper presents an experimental study to evaluate the effect of underbalance on perforation performance in the Fleming gas-condensate reservoir. Fleming analogue rock cores were perforated with single shaped charge perforators, and flow tested under simulated downhole conditions. Nitrogen gas was used as the pore fluid for all tests. A brief description of the test facility is included. Cores were taken from outcrop rock chosen to match, as closely as reasonably possible, selected properties of the Fleming reservoir sandstone; in particular, unconfined compressive strength, porosity, permeability, grain size distribution, sorting and shape. The perforated cores were examined in detail using flow performance comparison, rock mechanical tests, probe permeameter tests, microscopic examination and x-ray scans.

  1. Modeling of performance behavior in gas condensate reservoirs using a variable mobility concept

    E-print Network

    Wilson, Benton Wade

    2004-09-30

    The proposed work provides a concept for predicting well performance behavior in a gas condensate reservoir using an empirical model for gas mobility. The proposed model predicts the behavior of the gas permeability (or mobility) function...

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

    Microsoft Academic Search

    Y. Hoshi; H. Yoshida

    2009-01-01

    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

  3. Equilibrium Computation for the Growth of Alpha Silicon Carbide from Silane and Propane in the Presence of Hydrogen or an Inert Gas

    Microsoft Academic Search

    Shigekazu Minagawa; textscHarry C. Gatos

    1971-01-01

    The equilibrium computation for the growth of alpha-SiC from silane and propane in an atmosphere of hydrogen or an inert gas is carried out. The dependence of the deposition ratios of alpha-SiC, Si(1) and C(graphite) and the partial pressures of the vapor species on the concentration of the reactants and on the temperature is analyzed in detail. It is shown

  4. New correlations for dew-point, specific gravity and producing yield for gas condensates

    E-print Network

    Ovalle Cortissoz, Adriana Patricia

    2002-01-01

    is removed from the top of the cell until the volume of the cell is returned to the volume when the test was begun at the dew point pressure. The fluid in the cell is brought to equilibrium and the volume of the retrograde liquid is measured. The gas... PROPERTIES AND BEHAVIOR OF GAS CONDENSATE FLUIDS . . . . . . . . . 5 2. 2. 1 Gas Condensate Phase Diagram. 2. 2. 2 Field Identification of Gas Condensates . . 2. 3 GAS CONDENSATE TESTS . . 2. 3. 1 Test Procedures . 2. 3. 2 Constant Composttion Expansion...

  5. Turbulent noncondensing and condensing gas jets in liquids

    NASA Astrophysics Data System (ADS)

    Sun, T. Y.; Chuech, S. G.; Parthasarathy, R. N.; Faeth, G. M.

    1985-08-01

    Gas injection into liquids is a fundamental multiphase flow which has several direct applications, e.g., stored chemical energy propulsion systems (SCEPS), direct-contact condensers, gas dissolution systems, reservoir destratification systems and nuclear-reactor pressure suppression systems. Stability of these flow is enhanced when an underexpanded jet is used; therefore, the interaction of supersonic wave structures with liquids in turbulent flow is also an issue. The objective of this phase of the study was to develop test apparatus relating to underexpanded air jets in air and turbulent subsonic gas jets in liquids. The air-jet-in-air apparatus was assembled and flow visualization tests were completed using continuous and spark Schlieren photography. Test apparatus for gas injection in liquids was assembled. Tests were also undertaken to study injector stability. Test results showed that jet instability for subsonic (adapted) flow could be controlled by placing a screen across the jet exit and controlling gas release at the surface or the bath (which can cause undesirable pressure fluctuations in the bath). For stable jets, the liquid/gas interface is continous near the jet exit and its position is influenced by the degree of underexpansion. A bubble cloud was observed near the interface, and it is also probable that a drop cloud in present as well. Analysis of this flow for subsonic jet exit conditions was implemented using the locally homogeneous flow approximation of multiphase flow.

  6. Process using serpentine heat exchange relationship for condensing substantially single component gas streams

    Microsoft Academic Search

    J. M. Geist; M. R. Alvarez; H. C. Rowles; H. L. Vines; D. W. Woodward

    1985-01-01

    A method is disclosed for cooling, condensing and sub-cooling a substantially single component gas stream by passing the gas stream through a heat exchange relationship with a vaporizing multicomponent stream so that carry-up of the condensed liquid phase is maintained without condensed phase backmixing and pot-boiling of the coolant stream is avoided. The single component gas stream is passed through

  7. Characterization and Dessolution Test results for the January 2005 DWPF Off Gas Condensate Tank Samples (U)

    Microsoft Academic Search

    Fellinger

    2005-01-01

    The Off Gas Condensate Tank (OGCT) at the Defense Waste Processing Facility (DWPF) collects the condensate from the off-gas system of the melter. The condensate stream contains entrained solids that collect in the OGCT. Water from the OGCT is re-circulated to the Steam Atomized Scrubber and quencher and may provide a mechanism for re-introducing the particulates into the off-gas system.

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

    SciTech Connect

    Bray, K. R.; Jiao, C. Q. [UES, Inc., 4401 Dayton-Xenia Rd, Dayton, Ohio 45432 (United States)] [UES, Inc., 4401 Dayton-Xenia Rd, Dayton, Ohio 45432 (United States); DeCerbo, J. N. [Air Force Research Laboratory, AFRL/RQQE, 1950 Fifth St., WPAFB, Ohio 45433 (United States)] [Air Force Research Laboratory, AFRL/RQQE, 1950 Fifth St., WPAFB, Ohio 45433 (United States)

    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.

  9. Bose Einstein condensation in a gas of Fibonacci oscillators

    NASA Astrophysics Data System (ADS)

    Algin, Abdullah

    2008-10-01

    We consider a system of two-parameter deformed boson oscillators whose spectrum is given by a generalized Fibonacci sequence. In order to establish the role of the deformation parameters (q1,q2) in the thermostatistics of the system, we calculate several thermostatistical functions in the thermodynamical limit and investigate the low temperature behavior of the system. In this framework, we show that the thermostatistics of the (q1,q2)-bosons can be studied using the formalism of Fibonacci calculus which generalizes the recently proposed formalism of q-calculus. We also discuss the conditions under which the Bose-Einstein condensation would occur in the present two-parameter generalized boson gas. However, the ordinary boson gas results can be obtained by applying the limit q1 = q2 = 1.

  10. Condensation

    NSDL National Science Digital Library

    2012-06-26

    In this activity, learners explore the process of condensation. After seeing water vapor condense, learners will help design a test to see if cooling water vapor has an effect on the rate of condensation.

  11. 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

  12. New correlations for dew-point, specific gravity and producing yield for gas condensates 

    E-print Network

    Ovalle Cortissoz, Adriana Patricia

    2002-01-01

    This work presents four newly developed correlations to estimate dew-point pressure, current specific gravity and producing yield of gas condensate reservoirs. The first correlation may be used to predict the dew-point pressure of the reservoir gas...

  13. A Modified Genetic Algorithm Applied to Horizontal Well Placement Optimization in Gas Condensate Reservoirs

    E-print Network

    Morales, Adrian

    2011-02-22

    A MODIFIED GENETIC ALGORITHM APPLIED TO HORIZONTAL WELL PLACEMENT OPTIMIZATION IN GAS CONDENSATE RESERVOIRS A Thesis by ADRIAN NICOLAS MORALES Submitted to the Office of Graduate Studies of Texas A&M University in partial... Condensate Reservoirs Copyright 2010 Adrian Nicolas Morales A MODIFIED GENETIC ALGORITHM APPLIED TO HORIZONTAL WELL PLACEMENT OPTIMIZATION IN GAS CONDENSATE RESERVOIRS A Thesis by ADRIAN NICOLAS MORALES Submitted to the Office of Graduate...

  14. A Modified Genetic Algorithm Applied to Horizontal Well Placement Optimization in Gas Condensate Reservoirs 

    E-print Network

    Morales, Adrian

    2011-02-22

    A MODIFIED GENETIC ALGORITHM APPLIED TO HORIZONTAL WELL PLACEMENT OPTIMIZATION IN GAS CONDENSATE RESERVOIRS A Thesis by ADRIAN NICOLAS MORALES Submitted to the Office of Graduate Studies of Texas A&M University in partial... Condensate Reservoirs Copyright 2010 Adrian Nicolas Morales A MODIFIED GENETIC ALGORITHM APPLIED TO HORIZONTAL WELL PLACEMENT OPTIMIZATION IN GAS CONDENSATE RESERVOIRS A Thesis by ADRIAN NICOLAS MORALES Submitted to the Office of Graduate...

  15. Analysis of Heating Systems and Scale of Natural Gas-Condensing Water Boilers in Northern Zones

    E-print Network

    Wu, Y.; Wang, S.; Pan, S.; Shi, Y.

    2006-01-01

    In this paper, various heating systems and scale of the natural gas-condensing water boiler in northern zones are discussed, based on a technical-economic analysis of the heating systems of natural gas condensing water boilers in northern zones...

  16. Analysis of Heating Systems and Scale of Natural Gas-Condensing Water Boilers in Northern Zones 

    E-print Network

    Wu, Y.; Wang, S.; Pan, S.; Shi, Y.

    2006-01-01

    In this paper, various heating systems and scale of the natural gas-condensing water boiler in northern zones are discussed, based on a technical-economic analysis of the heating systems of natural gas condensing water boilers in northern zones...

  17. 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).

  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. [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

  20. Improvement of the sensitivity of opto-acoustic trace gas analysis by condensation

    SciTech Connect

    Slatkine, M.

    1981-01-01

    It is suggested that the minimum detectable concentration of a trace gas in an optoacoustically monitored sample of air could be decreased by five orders of magnitude by condensing the sample and optoacoustically monitoring the liquid phase.

  1. Modeling of performance behavior in gas condensate reservoirs using a variable mobility concept 

    E-print Network

    Wilson, Benton Wade

    2004-09-30

    used for the analysis of well test data from gas condensate reservoirs consider the radial composite reservoir model, which utilizes a "step change" in permeability at some radial distance away from the wellbore. Using our proposed solution we can...

  2. Increasing Well Productivity in Gas Condensate Wells in Qatar's North Field 

    E-print Network

    Miller, Nathan

    2010-07-14

    INCREASING WELL PRODUCTIVITY IN GAS CONDENSATE WELLS IN QATAR?S NORTH FIELD A Thesis by NATHAN MILLER Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE December 2009 Major Subject: Petroleum Engineering INCREASING WELL PRODUCTIVITY IN GAS CONDENSATE WELLS IN QATAR?S NORTH FIELD A Thesis by NATHAN MILLER Submitted to the Office of Graduate Studies...

  3. Spontaneous spin textures in dipolar spinor condensates: A Dirac string gas approach

    NASA Astrophysics Data System (ADS)

    Lian, Biao

    2015-05-01

    We study the spontaneous spin textures induced by magnetic dipole-dipole interaction in ferromagnetic spinor condensates under various trap geometries. At the mean-field level, we show the system is dual to a Dirac string gas with a negative string tension in which the ground state spin texture can be easily determined. We find that three-dimensional condensates prefer a meronlike vortex texture, quasi-one-dimensional condensates prefer the axially polarized flare texture, while condensates in quasi-two-dimensions exhibit either a meron texture or an in-plane polarized texture.

  4. Experimental and computational studies on absorption and desorption of multicomponent hydrogen isotopes from inert gas mixtures in a yttrium particle bed

    NASA Astrophysics Data System (ADS)

    Fukada, S.; Nakahara, T.; Mitsuishi, N.

    1990-05-01

    For the recovery of multicomponent hydrogen isotopes from inert gas mixtures, a yttrium particle bed was numerically and experimentally investigated. The material balance equations for each hydrogen isotope component in the bed were computed in terms of a mass transfer coefficient for diffusion in a solid particle, that in a fluid film, and an absorption rate constant on solid particle surfaces. The numerical curves could be fitted to the experimental effluent data for absorption and desorption, and the roll-up of deuterium due to a higher equilibrium pressure was observed in the experimental effluent curves for absorption. It was found that the value of the isotopic separation factor of protium and deuterium was 1.05 for a yttrium hydride phase.

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

    E-print Network

    Kaur, Kiranpreet; Sahoo, B K

    2015-01-01

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

  6. Genetic types of gas-condensates and oils from the southern Siberian platform

    SciTech Connect

    Sorokova, E.I.; Fomicheva, L.N.; Samsonov, Yu.V.; Bobileva, A.A.

    1986-09-01

    In the southern part of the Siberian platform, oil, gas, and gas-condensate have been discovered in Riphean-Vendian and Lower Cambrian sediments. Analysis of hydrocarbon distribution shows four zones of petroleum accumulation: (I) gas ( less than or equal to 1300 m), (II) oil-gas with possible gas-condensate accumulations (1300-2300 m), (III) oil-gas-condensate (2300-2800 m), and (IV) gas-condensate with possible oil accumulations (2800-3300 m or deeper). These zones correspond to definite formation- temperature and formation-pressure intervals. Attention is drawn to the fact that gas-condensate accumulations are present in all the recognized zones, with the exception of Zone I, and oil accumulations have been identified in Zones II and III. Thus, the problem of separate prediction of such accumulations at depth may be resolved only during a study of the generation phase zonation of the hydrocarbons. The present phase state of the hydrocarbons in the pools is a result of a lengthy evolution of phase zonation during the historical development of the region, from the time of generation and migration of the hydrocarbons to the time of their accumulation and retention in the traps. The evolution of the processes of generation and accumulation of hydrocarbons in the petroliferous complexes is described. 6 references, 2 figures.

  7. Experimental and analytical study of the effects of noncondensable gas in a passive condenser system

    NASA Astrophysics Data System (ADS)

    Oh, Seungmin

    Passive Containment Cooling System (PCCS) of the Simplified Boiling Water Reactor (SBWR) is a passive condenser system which is designed to remove energy from the reactor containment during a postulated reactor accident. The presence of noncondensable gas in the vapor can greatly reduce the performance of condensers. Hence a detailed knowledge of the heat removal performance of the PCCS in the presence of noncondensable gas is crucial for the safety and design optimization of the SBWR. The purpose of the present study is the experimental and theoretical investigation of the effects of noncondensable gas in a passive condenser system. Condensation experiments were performed for a vertical tube submerged in water pool. The present experimental data provide a new database for complete condensation, cyclic venting and through flow modes of the passive condenser. Cyclic venting mode was simulated by a control volume analysis. Analysis results showed that venting period decreases with noncondensable gas fraction. It was found that inception of venting can occur before the condenser is fully filled with noncondensable gas. A boundary layer model was developed for the prediction of the film condensation with noncondensable gas in a vertical tube. Full set of the governing equations for the liquid film and vapor-gas mixture regions were solved. A heat and mass analogy model was also developed with a specific purpose for use in the thermal hydraulic system analysis code. In the vapor-gas mixture region, general momentum, heat and mass transport relations derived by analytic method were used with the consideration of surface suction effect. The predictions from the models were compared with the experimental data and the agreement was satisfactory. A mechanistic condensation correlation was developed based on the experimental data and the analysis results. It contains all the heat transfer components in its functional relationships. New correlation can provide accurate estimation of local condensation heat transfer coefficient for wide range of operating parameters. The assessment of wall condensation models in RELAP5 code was performed. Experimental conditions were simulated with RELAP5. Code simulation showed quite different results compared with data. Therefore, the condensation model in RELAP5 needs to be improved.

  8. Results for the DWPF Slurry Mix Evaporator Condensate Tank, Off Gas Condensate Tank, And Recycle Collection Tank Samples

    SciTech Connect

    TERRI, FELLINGER

    2004-12-21

    The Defense Waste Processing Facility, DWPF, currently generates approximately 1.4 million gallons of recycle water per year during Sludge-Only operations. DWPF has minimized condensate generation to 1.4 million gallons by not operating the Steam Atomized Scrubbers, SASs, for the melter off gas system. By not operating the SASs, DWPF has reduced the total volume by approximately 800,000 gallons of condensate per year. Currently, the recycle stream is sent to back to the Tank Farm and processed through the 2H Evaporator system. To alleviate the load on the 2H Evaporator system, an acid evaporator design is being considered as an alternate processing and/or concentration method for the DWPF recycle stream. In order to support this alternate processing option, the DWPF has requested that the chemical and radionuclide compositions of the Off Gas Condensate Tank, OGCT, Slurry Mix Evaporator Condensate Tank, SMECT, Recycle Collection Tank, RCT, and the Decontamination Waste Treatment Tank, DWTT, be determined as a part of the process development work for the acid evaporator design. Samples have been retrieved from the OGCT, RCT, and SMECT and have been sent to the Savannah River National Laboratory, SRNL for this characterization. The DWTT samples have been recently shipped to SRNL. The results for the DWTT samples will be issued at later date.

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

    Microsoft Academic Search

    Lisa M. Gieg; R. S. Tanner; S. H. Jr. Harris; K. L. Sublette; J. M. Suflita; R. V. Kolhatkar

    1999-01-01

    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

  10. 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.

  11. Inert electrode connection

    DOEpatents

    Weyand, J.D.; Woods, R.W.; DeYoung, D.H.; Ray, S.P.

    1985-02-19

    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 1,200--1,500 C. 5 figs.

  12. On condensation of a one-dimensional nonideal Boson gas

    NASA Astrophysics Data System (ADS)

    Papoyan, Vl. V.; Zagrebnov, V. A.

    1985-11-01

    We report the properties of a one-dimensional model which exhibits Bose-Einstein condensation. The problem of canonical and grand canonical ensemble equivalence is considered. A strong equivalence is shown to be connected with uniqueness of the limiting Gibbs states.

  13. 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.

  14. Emission characteristics and parameters of gas-discharge plasma in mixtures of heavy inert gases with chlorine

    Microsoft Academic Search

    A. K. Shuaibov; A. N. Malinin

    2009-01-01

    The ultraviolet (UV) radiation from longitudinal glow-discharge plasma in three- and four-component mixtures of argon, krypton,\\u000a and xenon with chlorine has been investigated. The total radiation of Ar, Kr, and Xe monochlorides and chlorine molecules\\u000a in the spectral range 170–310 nm has been optimized with respect to the composition and the pressure of gas mixtures, as well\\u000a as the discharge

  15. Emission characteristics and parameters of gas-discharge plasma in mixtures of heavy inert gases with chlorine

    Microsoft Academic Search

    A. K. Shuaibov; A. N. Malinin

    2009-01-01

    The ultraviolet (UV) radiation from longitudinal glow-discharge plasma in three- and four-component mixtures of argon, krypton, and xenon with chlorine has been investigated. The total radiation of Ar, Kr, and Xe monochlorides and chlorine molecules in the spectral range 170-310 nm has been optimized with respect to the composition and the pressure of gas mixtures, as well as the discharge

  16. Experimental investigation on fiber and CO2 inert gas fusion cutting of AZ31 magnesium alloy sheets

    NASA Astrophysics Data System (ADS)

    Scintilla, L. D.; Tricarico, L.

    2013-03-01

    The influence of processing parameters and laser source type on cutting edge quality of AZ31 magnesium alloy sheets and differences in cutting efficiency between fiber and CO2 lasers were studied. A first part of the cutting experiments compared a fiber and CO2 laser source when cutting 1 mm thick sheets in continuous wave mode and using Argon as an assist gas. The effects of cutting speed and assist gas pressure were investigated and optimal conditions were identified. In the second part of the experimental investigation, 3.3 mm thick sheets were cut using fiber laser. Focal position and cutting speed were varied in order to detect the optimal combination of processing parameters to obtain the best edge quality. For both sheet thicknesses investigated, surface roughness, dross height, and striation pattern inclination were measured. Cutting quality assessment and classification was carried out according to UNI EN ISO 9013 standard. Results showed that productivity, process efficiency and cutting edges quality obtained using fiber lasers outperform CO2 laser performances and therefore are considered suitable for application like sheet metal trimming.

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-11-01

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

  19. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

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

  1. Emission characteristics and parameters of gas-discharge plasma in mixtures of heavy inert gases with chlorine

    NASA Astrophysics Data System (ADS)

    Shuaibov, A. K.; Malinin, A. N.

    2009-04-01

    The ultraviolet (UV) radiation from longitudinal glow-discharge plasma in three- and four-component mixtures of argon, krypton, and xenon with chlorine has been investigated. The total radiation of Ar, Kr, and Xe monochlorides and chlorine molecules in the spectral range 170-310 nm has been optimized with respect to the composition and the pressure of gas mixtures, as well as the discharge current. The mean output power, the electric power of discharge, and the efficiency of a broadband low-pressure exciplex halogen lamp have been determined. Parameters of the glow discharge in Ar-Kr-Cl2 and Kr-Xe-Cl2 mixtures have been simulated numerically. The electron energy distribution functions have been determined through the solution of the Boltzmann kinetic equation. These functions have been used to calculate the plasma parameters, namely, electron transfer characteristics, specific losses of discharge power for electronic processes, and ionization and attachment coefficients.

  2. Magnetic Transitions and Condensation in a Bose-Gas

    NASA Astrophysics Data System (ADS)

    Poluektov, Yu. M.; Savchenko, V. M.

    2015-06-01

    Magnetic transitions and Bose-Einstein condensation (BEC) are studied in a self-consistent field model, analogous to the model of a molecular field in the theory of ferromagnetism. It is shown that the present model is internally consistent and suitable for description at any value of a dimensionless parameter characterizing the system. Different possible types of phase transitions, at which magnetization and BEC density emerge either continuously or discontinuously, are considered. Critical values of the phenomenological parameter, at which the character of phase transitions changes, are calculated. The phase diagram in temperature-particle number density coordinates is plotted.

  3. A computationally efficient aerosol nucleation/condensation method: Pseudo-steady state gas phase sulfuric acid

    NASA Astrophysics Data System (ADS)

    Adams, P. J.; Pierce, J. R.

    2007-12-01

    Aerosol nucleation and condensation are two processes that compete for gas phase sulfuric acid when it is formed in the atmosphere. Without approximations, accurate numerical integration of aerosol microphysics requires time steps on the order of seconds or less when nucleation is occurring, significantly shorter than the time steps required by other processes governing aerosol microphysics. This computational burden makes the explicit numerical simulation burdensome in 3-dimensional atmospheric models. We have developed an efficient method for simulating nucleation/condensation by assuming that gas phase sulfuric acid is at a pseudo- steady state (PSS) concentration determined by chemical generation and its loss by nucleation and condensation. The time step for nucleation/condensation is then governed by 1) the change in the condensation sink, 2) the change in the generation rate of sulfuric acid, 3) the coagulation timescale, or 4) a master time step in the model. The PSS assumption fails only when the time for sulfuric acid to reach its PSS state concentration is not significantly shorter than the four timescales above. This may occur when the following conditions are met 1) the condensation sink is less than 10-3-10-4 s-1, 2) nucleation is not occurring, and 3) the gas phase production rate is changing. These conditions are not frequently met for a long period of time in the atmosphere. The PSS assumption allows for time step increases of two to three orders of magnitude during nucleation events in typical atmospheric conditions and has been shown to reduce the nucleation/condensation computational time by a factor of 10-100.

  4. Gas Phase Studies of N-Heterocyclic Carbene-Catalyzed Condensation Reactions.

    PubMed

    Tian, Yuan; Lee, Jeehiun K

    2015-07-01

    N-Heterocyclic carbenes (NHCs) catalyze Umpolung condensation reactions of carbonyl compounds, including the Stetter reaction. These types of reactions have not heretofore been examined in the gas phase. Herein, we explore the feasibility of examining these reactions in the absence of solvent. A charge-tagged thiazolylidene catalyst is used to track the reactions by mass spectrometry. We find that the first Umpolung step, the addition of the NHC catalyst to a carbonyl compound to form the "Breslow intermediate", does not readily proceed in the gas phase, contrary to the case in solution. The use of acylsilanes in place of the carbonyl compounds appears to solve this issue, presumably because of a favorable Brook rearrangement. The second addition reaction, with enones, does not occur under our gas phase conditions. These reactions do occur in solution; the differential reactivity between the condensed and gas phases is discussed, and calculations are used to aid in the interpretation of the results. PMID:26066314

  5. Impact of relative permeability models on fluid flow behavior for gas condensate reservoirs 

    E-print Network

    Zapata Arango, Jose? Francisco

    2002-01-01

    and on the quantification of their impact on reservoir fluid flow and well performance. We selected three relative permeability models to compare the results obtained in the modeling of relative permeabilities for a published North Sea gas condensate reservoir. The models...

  6. THE EFFECTS OF NON-CONDENSIBLE GAS AND SALINITY ON STEAM ADSORPTION

    E-print Network

    Stanford University

    % by weight of saline solution was added to the rock sample. Addition of salt to the sample enabledTHE EFFECTS OF NON-CONDENSIBLE GAS AND SALINITY ON STEAM ADSORPTION A REPORT SUBMITTED.1 Effects of GO2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2 Effects of Salinity

  7. Shock waves in a one-dimensional Bose gas: from a Bose-Einstein condensate to a Tonks gas

    E-print Network

    Bogdan Damski

    2006-04-03

    We derive and analyze shock-wave solutions of hydrodynamic equations describing repulsively interacting one dimensional Bose gas. We also use the number-conserving Bogolubov approach to verify accuracy of the Gross-Pitaevskii equation in shock wave problems. We show that quantum corrections to dynamics of shocks (dark-shock-originated solitons) in a Bose-Einstein condensate are negligible (important) for a realistic set of system parameters. We point out possible signatures of a Bose-Einstein condensate -- Tonks crossover in shock dynamics. Our findings can be directly verified in different experimental setups.

  8. Experimental study of unsteady state filtration of gas condensate system at the pressure above the dew point

    SciTech Connect

    Babaev, R.D.; Suleymanov, A.A.; Shahiduzzaman, M. [Azerbaijan State Oil Academy, Baku (Azerbaijan). Dept. of Development and Production of Oil Fields

    1997-04-01

    The experimental study investigates the unsteady filtration of a gas condensate system at pressure above the dew point. It is assumed that the motion of a gas condensate mixture in a porous medium at a pressure 1.5--1.7 times higher than the dew point pressure does not comply with gas filtration rules. The results explain the process of forming microembryonics of the new phase, which can be used in project planning as well as during exploitation of gas condensate fields at reservoir pressure.

  9. Application of the parallel multicanonical method to lattice gas condensation

    NASA Astrophysics Data System (ADS)

    Zierenberg, Johannes; Wiedenmann, Micha; Janke, Wolfhard

    2014-05-01

    We present the speedup from a novel parallel implementation of the multicanonical method on the example of a lattice gas in two and three dimensions. In this approach, all cores perform independent equilibrium runs with identical weights, collecting their sampled histograms after each iteration in order to estimate consecutive weights. The weights are then redistributed to all cores. These steps are repeated until the weights are converged. This procedure benefits from a minimum of communication while distributing the necessary amount of statistics efficiently. Using this method allows us to study a broad temperature range for a variety of large and complex systems. Here, a gas is modeled as particles on the lattice, which interact only with their nearest neighbors. For a fixed density this model is equivalent to the Ising model with fixed magnetization. We compare our results to an analytic prediction for equilibrium droplet formation, confirming that a single macroscopic droplet forms only above a critical density.

  10. 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.

  11. Inert gas ion thruster development

    NASA Technical Reports Server (NTRS)

    Ramsey, W. D.

    1980-01-01

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

  12. 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

  13. Partial inerting—an additional degree of freedom in dust explosion protection

    Microsoft Academic Search

    Rolf K Eckhoff

    2004-01-01

    When applying partial inerting the gas (most often air) in which the explosible dust is dispersed is mixed with a fraction of inert gas (e.g. nitrogen) considerably smaller than that required for complete inerting. This reduces both the explosibility and the ignition sensitivity of the dust cloud. The effects on KSt (explosion violence) and MIE (minimum ignition energy) are particularly

  14. Condensed fraction of an atomic Bose gas induced by critical correlations.

    PubMed

    Smith, Robert P; Tammuz, Naaman; Campbell, Robert L D; Holzmann, Markus; Hadzibabic, Zoran

    2011-11-01

    We study the condensed fraction of a harmonically trapped atomic Bose gas at the critical point predicted by mean-field theory. The nonzero condensed fraction f(0) is induced by critical correlations which increase the transition temperature T(c) above T(c) (MF). Unlike the T(c) shift in a trapped gas, f(0) is sensitive only to the critical behavior in the quasiuniform part of the cloud near the trap center. To leading order in the interaction parameter a/?(0), where a is the s-wave scattering length and ?(0) the thermal wavelength, we expect a universal scaling f(0) proportionally (a/?(0))(4). We experimentally verify this scaling using a Feshbach resonance to tune a/?(0). Further, using the local density approximation, we compare our measurements with the universal result obtained from Monte Carlo simulations for a uniform system, and find excellent quantitative agreement. PMID:22181587

  15. 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.

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

    NASA Technical Reports Server (NTRS)

    Colvin, James E.; Landis, Geoffrey A.

    1992-01-01

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

  17. 33 CFR 154.824 - Inerting, enriching, and diluting systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  18. Condensation of N bosons. II. Nonequilibrium analysis of an ideal Bose gas and the laser phase-transition analogy 

    E-print Network

    Kocharovsky, VV; Scully, Marlan O.; Zhu, S. Y.; Zubairy, M. Suhail

    2000-01-01

    A nonequilibrium approach to the dynamics and statistics of the condensate of an ideal N-atom Bose gas cooling via interaction with a thermal reservoir using the canonical ensemble is developed. We derive simple analytical expressions...

  19. A thermodynamic approach on vapor-condensation of corrosive salts from flue gas on boiler tubes in waste incinerators

    Microsoft Academic Search

    Nobuo Otsuka

    2008-01-01

    Thermodynamic equilibrium calculation was conducted to understand the effects of tube wall temperature, flue gas temperature, and waste chemistry on the type and amount of vapor-condensed “corrosive” salts from flue gas on superheater and waterwall tubes in waste incinerators. The amount of vapor-condensed compounds from flue gases at 650–950°C on tube walls at 350–850°C was calculated, upon combustion of 100g

  20. 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.

  1. Bose-Einstein condensation in the relativistic pion gas: Thermodynamic limit and finite size effects

    SciTech Connect

    Begun, V. V. [Bogolyubov Institute for Theoretical Physics, Kiev (Ukraine); Gorenstein, M. I. [Bogolyubov Institute for Theoretical Physics, Kiev (Ukraine); Frankfurt Institute for Advanced Studies, Frankfurt (Germany)

    2008-06-15

    We consider the Bose-Einstein condensation (BEC) in a relativistic pion gas. The thermodynamic limit when the system volume V goes to infinity as well as the role of finite size effects are studied. At V{yields}{infinity} the scaled variance for particle-number fluctuations, {omega}=<{delta}N{sup 2}>/, converges to finite values in the normal phase above the BEC temperature, T>T{sub C}. It diverges as {omega}{proportional_to}V{sup 1/3} at the BEC line T=T{sub C}, and {omega}{proportional_to}V at Tcondensate. Possible experimental signals of the pion BEC in finite systems created in high-energy proton-proton collisions are discussed.

  2. Temporal condensed matter physics in gas-filled photonic crystal fibers

    E-print Network

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

    2014-01-01

    Raman effect in gases can generate an extremely long-living wave of coherence that can lead to the establishment of an almost perfect 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 only, now realized with purely optical means in the temporal domain.

  3. Local observation of pair-condensation in a Fermi gas at unitarity

    NASA Astrophysics Data System (ADS)

    Fenech, Kristian; Lingham, Marcus; Hoinka, Sascha; Vale, Chris

    2014-05-01

    Ultracold Fermi gases near a Feshbach resonance provide a means to investigate the physics of strongly interacting quantum systems. Through the use of spatially resolved Bragg spectroscopy we are able to measure the homogenous density-density response function of a Fermi gas at unitarity. The resulting Bragg response provides a clear signature of pair-condensation at temperatures below the superfluid transition temperature. The method used to obtain the local measurement is generalizable to any homogenous parameter which satisfies the local density approximation, providing a new tool that can be used where techniques such as the inverse-Abel transform are no longer applicable.

  4. Asymptotic formula for the condensate wave function of a trapped Bose gas

    SciTech Connect

    Margetis, Dionisios [Gordon McKay Laboratory, Harvard University, Cambridge, Massachusetts 02138-2901 (United States)] [Gordon McKay Laboratory, Harvard University, Cambridge, Massachusetts 02138-2901 (United States)

    2000-05-01

    An analytical property is pointed out for the universal differential equation first derived by Dalfovo, Pitaevskii, and Stringari for the condensate wave function at the boundary of a trapped Bose gas. Specifically, the constant multiplying the Airy function of the solution asymptotically outside the trap is {radical}(2). Accordingly, the Wentzel-Kramers-Brillouin approximation is determined in the case of a spherically symmetric harmonic potential. This calculation is related to Josephson-type currents flowing between well-separated traps. (c) 2000 The American Physical Society.

  5. 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.

  6. 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

  7. Gas scavenging of insoluble vapors: Condensation of methyl salicylate vapor onto evaporating drops of water

    NASA Astrophysics Data System (ADS)

    Seaver, Mark; Peele, J. R.; Rubel, Glenn O.

    We have observed the evaporation of acoustically levitated water drops at 0 and 32% relative humidity in a moving gas stream which is nearly saturated with methyl salicylate vapor. The initial evaporation rate is characteristic of a pure water drop and gradually slows until the evaporation rate becomes that of pure methyl salicylate. The quantity of condensed methyl salicylate exceeds its Henry's law solubility in water by factors of more than 30-50. This apparent violation of Henry's law agrees with the concentration enhancements in the liquid phase found by glotfelty et al. (1987, Nature235, 602-605) during their field measurements of organophorus pesticides in fog water. Under our conditions, visual evidence demonstrates the presence of two liquid phases, thus invalidating the use of Henry's law. A continuum evaporation-condensation model for an immiscible two-component system which accounts for evaporative self-cooling of the drop correctly predicts the amount of methyl salicylate condensed onto the water drops.

  8. Horizontal in-tube condensation in the presence of a noncondensable gas

    NASA Astrophysics Data System (ADS)

    Wu, Tiejun

    A horizontal heat exchanger design has been proposed for the Passive Containment Cooling System (PCCS) condenser of future Boiling Water Reactors (BWR). Compared to the vertical design, it has several advantages, but the challenge is that there is a lack of mechanistic understanding of the heat transfer and fluid flow phenomena occurring in the heat exchanger tubes. There is also the need for mechanistic analysis tools that can assess condenser performance. This research experimentally investigates the local heat transfer from the condensation of steam in the presence of noncondensable gas in a single horizontal tube. To capture the asymmetrical nature of horizontal two-phase flow and heat transfer, the heat fluxes at the top and bottom of the condenser tube were obtained. A novel thermocouple was designed and fabricated to accurately measure the inside wall temperature from which a local heat flux can be deduced. The calibration technique of the thermocouple pairs was also developed. This local heat flux measurement technique is an original method for data which had previously been unattainable. It is applicable to phase-change heat exchangers of any inclination. Tests with parameters that cover both design base accident and severe accident conditions have been performed. Analysis showed that the heat transfer at the top of the tube is much better than that at the bottom of the tube, which shows that for most of the conditions the liquid phase distribution has a great effect on the heat transfer. The effect of noncondensable gas has been qualitatively studied both locally and globally from the experimental data. A mechanistic model was developed independent of the experimental data and was verified by the experimental data. Diffusion layer theory was used to account for the effect of noncondensable gas. For annular flow, the phenomenon inside the tube was assumed to be symmetrical. For wavy and stratified flow, the tube is divided into top and bottom parts peripherally based on the local phase distribution. The heat transfer mode across the liquid film was considered differently for the top and bottom part of the tube. The predictions from the mechanistic model were compared with the experimental data both locally and globally, and the agreement was satisfactory.

  9. The noncondensable gas effects on loss-of-coolant accident steam condensation loads in boiling water reactor pressure suppression pool

    SciTech Connect

    Kukita, Y.; Namatame, K.; Shiba, M.; Takeshita, I.

    1983-11-01

    The noncondensable gas effects on the loss-ofcoolant-accident-induced steam condensation loads in the boiling water reactor pressure suppression pool have been investigated with regard to experimental data obtained from a large-scale multivent test program. Previous studies have noted that the presence of the noncondensable gas (air), which initially fills the containment drywell space, stabilizes the direct-contact condensation in the pressure suppression pool and hampers onset of the chugging phenomenon, which induces most significant steam condensation load onto the pool boundary. This was found to be true for the tests with relatively small-break diameters, where the maximum steam mass fluxes in the vent pipe were lower than the upper threshold value for the onset of chugging. However, in the tests with the maximum vent steam mass fluxes moderately higher than the chugging upper threshold value, early depletion of the noncondensable gas tended to result in significant stabilization of steam condensation accompanied by an excursion of temperature of pool water surrounding the vent pipe outlets, which led to a delayed onset of chugging. Due to this combined influence of the noncondensable gas and nonuniform pool temperature, and due to dependence of magnitude of chugging load on the vent steam mass flux, the peak magnitude of the steam condensation load appearing in a blowdown can be very sensitive to the initial and break conditions.

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

    NASA Astrophysics Data System (ADS)

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

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

  11. One-loop inert and pseudo-inert minima

    E-print Network

    Ferreira, P M

    2015-01-01

    We analyse the differences between inert and pseudo-inert vacua in the 2HDM, both at tree-level and one-loop. The validity of tree-level formulae for the relative depth of the potential at both minima is studied. The one-loop analysis shows both minima can coexist in regions of parameter space forbidden at tree-level.

  12. One-loop inert and pseudo-inert minima

    E-print Network

    P. M. Ferreira; B. Swiezewska

    2015-06-03

    We analyse the differences between inert and pseudo-inert vacua in the 2HDM, both at tree-level and one-loop. The validity of tree-level formulae for the relative depth of the potential at both minima is studied. The one-loop analysis shows both minima can coexist in regions of parameter space forbidden at tree-level.

  13. Titanium-sponge bed to scavenge tritium from inert gases

    NASA Astrophysics Data System (ADS)

    Nishikawa, Masabumi; Kido, Hidetoshi; Kotoh, Kenji; Sugisaki, Masayasu

    1983-03-01

    Chemical getters can be used to scavenge hydrogen isotopes from inert gases in HTGRs or fusion reactors. It is necessary that getter materials have a large gas-solid mass transfer capacity coefficient for scavenging hydrogen isotopes from inert gases. Absorption and desorption characteristics of hydrogen isotopes in a titanium sponge bed is examined in this study. Discussions are mainly based on data obtained from breakthrough curves. Experimental results show that the titanium-sponge bed is a good candidate material for scavenging and fixation of tritium from inert gases.

  14. Fluid inclusion evidence for an early, marine-sourced oil charge prior to gas-condensate migration, Bayu-1, Timor Sea, Australia

    Microsoft Academic Search

    Simon C. George; Mark Lisk; Peter J. Eadington

    2004-01-01

    The distribution of oil-bearing fluid inclusions (FI) in currently gas-bearing Jurassic reservoir sandstones from Bayu-1 (Northern Bonaparte Basin, Timor Sea) is consistent with the Bayu gas-condensate field originally containing a palaeo-oil column beneath a thick palaeo-gas cap. In order to assess the origin of the oil trapped in the FIs and its relationship, if any, to the gas condensate, a

  15. Ground-State Energy and Condensate Density of a Dilute Bose Gas Revisited

    NASA Astrophysics Data System (ADS)

    Tsutsui, Kazumasa; Kita, Takafumi

    2013-06-01

    The ground-state energy per particle E/N and condensate density n0 of a dilute Bose gas are studied with a self-consistent perturbation expansion satisfying the Hugenholtz--Pines theorem and conservation laws simultaneously. A class of Feynman diagrams for the self-energy, which has escaped consideration so far, is shown to add an extra constant cip˜ O(1) to the expressions reported by Lee et al. [Phys. Rev. 106 (1957) 1135] as E/N=(2?\\hbar2an/m)[1+(128/15\\sqrt?+16cip/5)\\sqrt{a3n}] and n0/n=1-(8/3\\sqrt?+cip)\\sqrt{a3n}, where a, n, and m are are the s-wave scattering length, particle density, and particle mass, respectively. We present a couple of estimates for cip; the third-order perturbation expansion yields cip=0.412.

  16. Size-selected cluster beam source based on radio frequency magnetron plasma sputtering and gas condensation

    SciTech Connect

    Pratontep, S.; Carroll, S.J.; Xirouchaki, C.; Streun, M.; Palmer, R.E. [Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)

    2005-04-01

    We report on a source for producing size-selected nanoclusters based on the combination of radio frequency magnetron plasma sputtering and gas condensation. The use of plasma sputtering to vaporize a target is applicable to a large range of materials; Ag, Au, Cu, and Si have been attempted to date. The source, combined with a time-of-flight mass filter, can produce clusters in the size range from 2 up to at least 70 000 atoms, depending on the target material, with a constant mass (M) resolution (M/{delta}M{approx}25) at an intensity that produces atomic monolayer coverage in as little as a few minutes. The source is also attached to an ultrahigh vacuum analysis chamber, which allows in situ surface chemical and structural analysis. Examples of cluster deposition experiments with the source are also presented.

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

    DOEpatents

    Durai-Swamy, Kandaswamy (Culver City, CA)

    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.

  18. The potential for intrinsic bioremediation of BTEX hydrocarbons in soil\\/ground water contaminated with gas condensate

    Microsoft Academic Search

    Abhijeet P. Borole; Kerry L. Sublette; Kevin T. Raterman; Minoo Javanmardian; J. Berton Fisher

    1997-01-01

    Gas condensate liquids contaminate soil and ground water at two gas production sites in the Denver Basin, CO. A detailed field\\u000a study was carried out at these sites to determine the applicability of intrinsic bioremediation as a remediation option. Ground\\u000a water monitoring at the field sites and analysis of soil cores suggested that intrinsic bioremediation is occurring at the\\u000a sites

  19. Performance analysis of compositional and modified black-oil models for rich gas condensate reservoirs with vertical and horizontal wells 

    E-print Network

    Izgec, Bulent

    2004-09-30

    It has been known that volatile oil and gas condensate reservoirs cannot be modeled accurately with conventional black-oil models. One variation to the black-oil approach is the modified black-oil (MBO) model that allows the use of a simple...

  20. Interstellar Silicate Analogs for Grain-surface Reaction Experiments: Gas-phase Condensation and Characterization of the Silicate Dust Grains

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

    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 Mg2SiO4 and Fe2SiO4, 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 H2 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 Mg2SiO4 and Fe2SiO4 described in this paper will be the topic of the next paper of this series.

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

    SciTech Connect

    Sabri, T.; Jäger, C. [Laboratory Astrophysics Group of the Max Planck Institute for Astronomy at the Friedrich Schiller University Jena Institute of Solid State Physics, Helmholtzweg 3, D-07743 Jena (Germany); Gavilan, L.; Lemaire, J. L.; Vidali, G. [Observatoire de Paris/Université de Cergy-Pontoise, 5 mail Gay Lussac, F-95000 Cergy-Pontoise (France); Mutschke, H. [Laboratory Astrophysics Group of the Astrophysical Institute and University Observatory, Friedrich Schiller University Jena Schillergässchen 3, D-07743 Jena (Germany); Henning, T., E-mail: tolou.sabri@uni-jena.de [Max Planck Institute for Astronomy Königstuhl 17, D-69117 Heidelberg (Germany)

    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.

  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. (Univ. of Oklahoma, Norman, OK (United States)); Kolhatkar, R.V. (Univ. of Tulsa, OK (United States). 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. Design studies for direct contact condensers with and without the presence of noncondensible gas

    SciTech Connect

    Nadig, R.

    1984-01-01

    Analytical models are presented to predict the condensation in film type direct contact condensation and related processes. The related processes include condensation on a thin film flowing over an isothermal vertical surface and condensation on tube bundles. In addition the effects of noncondensible gases on the above processes are examined. The analysis is based on conservation laws alone and does not use any empirical data. The theoretical models developed are applicable for condensation of a vapor on a thin film which is the same or different from the condensate. However, the cases studied are those of steam condensing on a thin film of water. Valuable design criteria and heat transfer behavior are presented that provide better insight in designing and understanding the performance of direct contact condensers.

  4. 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.

  5. 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.

  6. 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

  7. Investigation of metal and metal oxide clusters small enough to constitute the critical size for gas phase nucleation in combustion processes. Final report, 1 October 1975-30 June 1979

    Microsoft Academic Search

    1980-01-01

    Over the course of this contract a variety of techniques have been employed to study the properties of small atomic and molecular clusters formed in the gas phase via homogeneous nucleation. The clustering occurs either in an adiabatic expansion of a condensable species (e.g. argon, krypton, xenon, or sulfur hexafluoride) in an inert carrier gas (e.g. helium), or as a

  8. Fatigue failure of an offshore condensate recycle line in a natural gas production field

    SciTech Connect

    El-Batahgy, A. [Welding Research Department, Central Metallurgical R and D Institute, Cairo (Egypt)]. E-mail: elbatahgy@yahoo.com; Zaghloul, B. [Central Metallurgical R and D Institute, Cairo (Egypt)

    2005-03-15

    After 2 years of operation, a condensate recycle line at a natural gas production field failed due to fatigue cracking. Fatigue was caused by a combination of both cyclic stresses related to an intermittant operational mode and stress concentration at the base of a fillet weld. Stress concentration was increased by weld surface defects, including undercut and overlap, that produced a sharp transition at the fillet weld base. Internal welding defects, such as porosity and lack of fusion, did not play a role in crack formation. On the other hand, the failure could be assisted by corrosion after exposing the crack surface to the atmospheric condition. The problem was solved by improving the geometry of the fillet weld so that acceptable contouring with a smooth transition at fillet weld base was obtained, reducing the stress concentration. Periodic inspection was scheduled to detect the existence of outer surface cracks and determine the necessary action to be done in order to avoid sudden failure and unexpected shut down.

  9. A common single-site Pt(II)-O(OH)x- species stabilized by sodium on "active" and "inert" supports catalyzes the water-gas shift reaction.

    PubMed

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

    2015-03-18

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

  10. 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.

  11. Treatment of UCG condensate by gas stripping, solvent extraction, activated carbon, and sludge

    Microsoft Academic Search

    M. J. Humenick; K. Shellenbarger

    1986-01-01

    This paper reports on the continued study of the treatment of UCG condensate by various processing schemes. The purpose of this work was to obtain design data for use in providing an optimal rather than a universal treatment scheme for UCG wastewater condensate. In the past, several treatment schemes have been studied and design data collected and published. This work

  12. Photochemical activity of Titan's low-altitude condensed haze.

    PubMed

    Gudipati, Murthy S; Jacovi, Ronen; Couturier-Tamburelli, Isabelle; Lignell, Antti; Allen, Mark

    2013-01-01

    Titan, the largest moon of Saturn and similar to Earth in many aspects, has unique orange-yellow colour that comes from its atmospheric haze, whose formation and dynamics are far from well understood. Present models assume that Titan's tholin-like haze formation occurs high in atmosphere through gas-phase chemical reactions initiated by high-energy solar radiation. Here we address an important question: Is the lower atmosphere of Titan photochemically active or inert? We demonstrate that indeed tholin-like haze formation could occur on condensed aerosols throughout the atmospheric column of Titan. Detected in Titan's atmosphere, dicyanoacetylene (C?N?) is used in our laboratory simulations as a model system for other larger unsaturated condensing compounds. We show that C4N2 ices undergo condensed-phase photopolymerization (tholin formation) at wavelengths as long as 355 nm pertinent to solar radiation reaching a large portion of Titan's atmosphere, almost close to the surface. PMID:23552063

  13. 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 (?-Fe2O3) and amorphous silica (SiO2) were prepared by CO2 laser co-vaporization (CoLAVA) of hematite powder (?-Fe2O3) and quartz sand (SiO2). The ?-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 ?-Fe2O3 inclusions to Janus NPs consisting of a ?-Fe2O3 and a SiO2 hemisphere to ?-Fe2O3 NPs each carrying one small SiO2 lens on its surface, (ii) the multiple ?-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 (?-Fe2O3) and amorphous silica (SiO2) were prepared by CO2 laser co-vaporization (CoLAVA) of hematite powder (?-Fe2O3) and quartz sand (SiO2). The ?-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 ?-Fe2O3 inclusions to Janus NPs consisting of a ?-Fe2O3 and a SiO2 hemisphere to ?-Fe2O3 NPs each carrying one small SiO2 lens on its surface, (ii) the multiple ?-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 ?-Fe2O3 inclusions (section S2), particle size distributions of the Fe2O3@SiO2 nanopowder samples (section S3), ?-potentials of aqueous dispersions of all ?-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

  14. Treatment of UCG condensate by gas stripping, solvent extraction, activated carbon, and sludge

    SciTech Connect

    Humenick, M.J.; Shellenbarger, K.

    1986-01-01

    This paper reports on the continued study of the treatment of UCG condensate by various processing schemes. The purpose of this work was to obtain design data for use in providing an optimal rather than a universal treatment scheme for UCG wastewater condensate. In the past, several treatment schemes have been studied and design data collected and published. This work presents new options for consideration and evaluation. The laboratory experimental project studied the following options: treatment of UCG condensate by (a) solvent extraction (Methyl isobutyl ketone, MIBK), ammonia stripping, and activated sludge; (b) solvent extraction by MIBK, ammonia stripping, and activated sludge with supplemental powdered activated carbon addition to the activated sludge unit; (c) ammonia stripping and dilution of the stripped UCG condensate with contaminated pattern water before treatment of the mixture with activated sludge. Performance and kinetic information is provided for each option, along with a determination of relative toxicity of feeds and effluents for options (a) and (b).

  15. Compression set in gas-blown condensation-cured polysiloxane elastomers

    Microsoft Academic Search

    Mogon Patel; Sarah Chinn; Robert S. Maxwell; Thomas S. Wilson; Stephen A. Birdsell

    2010-01-01

    Accelerated thermal ageing studies on foamed condensation cured polysiloxane materials have been performed in support of life assessment and material replacement programmes. Two different types of filled hydrogen-blown and condensation cured polysiloxane foams were tested; commercial (RTV S5370), and an in-house formulated polysiloxane elastomer (Silfoam). Compression set properties were investigated using Thermomechanical (TMA) studies and compared against two separate longer

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

    SciTech Connect

    He Shihai; Jing Ying; Wang Jianping [Department of Electrical and Computer Engineering and Center for Micromagnetics and Information Technology (MINT), University of Minnesota, 200 Union St. SE, 4-174 EE/CSci, Minneapolis, Minnesota 55455 (United States)

    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.

  17. 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 alka

  18. 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.

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

    Microsoft Academic Search

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

    2004-01-01

    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

  20. Method for removing metal vapor from gas streams

    DOEpatents

    Ahluwalia, R. K. (6440 Hillcrest Dr., Burr Ridge, IL 60521); Im, K. H. (925 Lehigh Cir., Naperville, IL 60565)

    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.

  1. 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.

  2. 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

  3. 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

  4. Detection of Inert Gases by Cold Electron Emission from Carbon Nanotube Emitters

    NASA Astrophysics Data System (ADS)

    Kim, Seongjeen

    In this work, different from the typical gas sensors responding by gas adsorption on their surface, a new gas sensor using carbon nanotubes (CNTs) as electron emitters is introduced for detecting inert gases which hardly possess chemical or electrical adsorption in normal conditions. The proposed sensor works by figuring out the variation of the dark current and the initial breakdown voltage on Paschen's law under applied high voltage. As they depend on the gas composition and the pressure in a sealed chamber, it is possible to detect the identity and the concentration of unknown inert gas species.

  5. 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.

  6. Condensation from gas–vapour mixtures in small non-circular tubes

    Microsoft Academic Search

    S. Krishnaswamy; H. S. Wang; J. W. Rose

    2006-01-01

    Careful measurements have been made during condensation of steam from steam–air mixtures flowing in a small, flattened, horizontal tube. The ranges of the relevant variables covered (inlet temperature, pressure, air mole fraction and mixture mass flow rate) were chosen to simulate those occurring in an exhaust heat-exchanger tube of a proposed fuel-cell engine. The experimental tube was cooled by water

  7. Reproductive effects of the water-accommodated fraction of a natural gas condensate in the Indo-Pacific reef-building coral Pocillopora damicornis.

    PubMed

    Villanueva, R D; Yap, H T; Montaño, M N E

    2011-11-01

    Toxic effects of the water-accommodated fraction (WAF) of a natural gas condensate on the reproduction of the brooding coral Pocillopora damicornis were studied in short-term (24 h) laboratory experiments. Coral fragments were exposed to varying concentrations of condensate WAF during different reproductive phases: gametogenesis, early embryogenesis, and late embryogenesis (when nighttime planulation occurs). During gametogenesis, exposure to condensate WAF did not inhibit subsequent production of larvae. On the other hand, exposure to >25% WAF of gravid corals, at early and late embryogenesis, resulted in abortion and early release of larvae, respectively, with higher percentages of larvae expelled in fragments treated with higher concentrations of condensate WAF at least 3h after onset of exposure. Aborted larvae during early embryogenesis were 'premature', as they are of small size (0.06±0.03 mm³), low metamorphic competency (54%), and white in coloration, with a pale brown oral end (indicating low density of zooxanthellae). Those larvae released at the latter part of embryogenesis are bigger in size (0.22±0.08 mm³), possess 100% metamorphic competency, and are brown in coloration (high density of zooxanthellae). Aside from direct effects on reproduction, fragment mortality index was higher in samples exposed to higher concentrations of condensate WAF (>25%), hence lowering the number of potentially reproducing polyps. Altogether, exposure to >25% natural gas condensate WAF for at least 3h can potentially disrupt the replenishment of coral populations due to negative effects on reproduction and early life processes. PMID:21862129

  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. 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.

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

    SciTech Connect

    NONE

    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.

  11. Flammability limits of dusts: Minimum inerting concentrations

    SciTech Connect

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

    1999-05-01

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

  12. Electrolyte vapor condenser

    DOEpatents

    Sederquist, R.A.; Szydlowski, D.F.; Sawyer, R.D.

    1983-02-08

    A system is disclosed for removing electrolyte from a fuel cell gas stream. The gas stream containing electrolyte vapor is supercooled utilizing conventional heat exchangers and the thus supercooled gas stream is passed over high surface area passive condensers. The condensed electrolyte is then drained from the condenser and the remainder of the gas stream passed on. The system is particularly useful for electrolytes such as phosphoric acid and molten carbonate, but can be used for other electrolyte cells and simple vapor separation as well. 3 figs.

  13. Drill pipe corrosion control using an inert drilling fluid

    SciTech Connect

    Caskey, B.C.; Copass, K.S.

    1981-01-01

    The results of a geothermal drill pipe corrosion field test are presented. When a low-density drilling fluid was required for drilling a geothermal well because of an underpressured, fractured formation, two drilling fluids were alternately used to compare drill pipe corrosion rates. The first fluid was an air-water mist with corrosion control chemicals. The other fluid was a nitrogen-water mist without added chemicals. The test was conducted during November 1980 at the Baca Location in northern New Mexico. Data from corrosion rings, corrosion probes, fluid samples and flow line instrumentation are plotted for the ten day test period. It is shown that the inert drilling fluid, nitrogen, reduced corrosion rates by more than an order of magnitude. Test setup and procedures are also discussed. Development of an onsite inert gas generator could reduce the cost of drilling geothermal wells by extending drill pipe life and reducing corrosion control chemical costs.

  14. 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...

  15. 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.

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

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

  17. Axial grading of inert matrix fuels

    SciTech Connect

    Recktenwald, G. D.; Deinert, M. R. [Dept. of Mechanical Engineering, Univ. of Texas, Austin, TX (United States)

    2012-07-01

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

  18. Helium in inert matrix dispersion fuels

    Microsoft Academic Search

    A. van Veen; R. J. M Konings; A. V Fedorov

    2003-01-01

    The behaviour of helium, an important decay product in the transmutation chains of actinides, in dispersion-type inert matrix fuels is discussed. A phenomenological description of its accumulation and release in CERCER and CERMET fuel is given. A summary of recent He-implantation studies with inert matrix metal oxides (ZrO2, MgAl2O4, MgO and Al2O3) is presented. A general picture is that for

  19. 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 ?-, and ?-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

  20. 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.

  1. Performance of the inertance pulse tube

    NASA Astrophysics Data System (ADS)

    de Boer, P. C. T.

    2002-03-01

    The rate of refrigeration of the inertance pulse tube (IPTR) is found as a function of the relevant parameters. In the simplified case of infinite volume of the reservoir and zero dead volume of the regenerator, these parameters are the dimensions of the inertance tube, the volume of the pulse tube, the conductance of the regenerator, the driving pressure, and the frequency. The effective conductance of the inertance tube is determined using a simple turbulent flow model. It is found that the performance of the IPTR is superior to that of the orifice pulse tube refrigerator (OPTR) over a limited range of frequencies. The improvement is explained in terms of the pressure amplitude in the pulse tube, the flow rate between the regenerator and the pulse tube, and the phase angle between these parameters. The analysis is extended to the case of finite reservoir and regenerator volumes. It is indicated how the results obtained can be useful in experimental work.

  2. 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. (Johannes-Kepler-Universitaet Linz (Austria))

    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.

  3. 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.

  4. Latest advances in the understanding of acid dewpoint corrosion: corrosion and stress corrosion cracking in combustion gas condensates

    Microsoft Academic Search

    W. M. M. Huijbregts; R. G. I. Leferink

    2004-01-01

    Corrosion failures due to condensing flue gases containing H2O, SO3, NOx and HCl still occur more often than might be expected. The corrosion failures can be of several types: general corrosion, pitting attack and stress corrosion cracking (SCC). The chemistry of condensing gases is discussed, and some examples of corrosion in large-scale installations are presented, including blast stoves for steel

  5. Inertness of Bonded Silica Gel Packings

    Microsoft Academic Search

    M. Ohhira; F. Ohmura; T. Hanai

    1989-01-01

    Stability and inertness of bonded silica gel packings were examined from the retention behavior of acidic and basic compounds, and also metal sensitive compounds. Bonded silica gels made from pure silica gel were stable in acidic and basic solutions, and did not interfere with chromatography of chelate reagents in reversed-phase liquid chromatography.

  6. 33 CFR 154.824 - Inerting, enriching, and diluting systems.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...false Inerting, enriching, and diluting systems. 154.824 Section 154.824 Navigation...HAZARDOUS MATERIAL IN BULK Vapor Control Systems § 154.824 Inerting, enriching, and diluting systems. (a) A vapor control system...

  7. 33 CFR 154.2107 - Inerting, enriching, and diluting systems.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Inerting, enriching, and diluting systems. 154.2107 Section 154.2107 ...MATERIAL IN BULK Marine Vapor Control Systems Transfer Facilities-Vcs Design and... Inerting, enriching, and diluting systems. This section applies only to...

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

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...false Inerting, enriching, and diluting systems. 154.824 Section 154.824 Navigation...HAZARDOUS MATERIAL IN BULK Vapor Control Systems § 154.824 Inerting, enriching, and diluting systems. (a) A vapor control system...

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

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...false Inerting, enriching, and diluting systems. 154.824 Section 154.824 Navigation...HAZARDOUS MATERIAL IN BULK Vapor Control Systems § 154.824 Inerting, enriching, and diluting systems. (a) A vapor control system...

  10. Effect of chemically inert particles on parameters and suppression of detonation in gases

    Microsoft Academic Search

    P. A. Fomin; J.-R. Chen

    2009-01-01

    An algorithm for calculating the parameters of a steady one-dimensional detonation wave in mixtures of a gas with chemically\\u000a inert particles and estimating the detonation-cell size in such mixtures is proposed. The calculated detonation parameters\\u000a and cell size in stoichiometric hydrogen-oxygen mixtures with W, Al2O3, and SiO2 particles are used to analyze the method of suppression of multifront gas detonation

  11. Children's understanding of changes of state involving the gas state, Part 2: Evaporation and condensation below boiling point

    Microsoft Academic Search

    Philip Johnson

    1998-01-01

    Deriving from a three?year longitudinal study which explored the development of children's concept of a substance (ages 11 to 14), part 2 of this paper (see Johnson 1998b) reports findings in relation to evaporation at room temperature and condensation of atmospheric water vapour. Part one had reported findings in relation to boiling water and the development of pupils’ understanding of

  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. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

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

  15. Contribution of polycyclic aromatic hydrocarbons and polar polycyclic aromatic compounds to the carcinogenic impact of flue gas condensate from coal-fired residential furnaces evaluated by implantation into the rat lung

    SciTech Connect

    Grimmer, G.; Brune, H.; Deutsch-Wenzel, R.; Dettbarn, G.; Misfeld, J.

    1987-05-01

    For identification of the substances chiefly responsible for the carcinogenic action of the emission condensate from coal-fired residential furnaces, the implantation method was used as a carcinogen-specific bioassay for comparison of the carcinogenic effect of various fractions with that of a total sample of flue gas condensate tested in 2 or 3 different doses. After implantation into the lungs of Osborne-Mendel rats, the condensate from coal-fired residential furnaces, a fraction containing polycyclic aromatic hydrocarbons (PAHs) and thiaarenes (sulfur-containing polycyclic aromatic compounds (S-PACs)) with 4-7 rings, as well as fraction containing more polar polycyclic aromatic compounds (PACs) and PAHs with higher molecular weight, induced lung carcinomas and sarcomas. According to probit analysis, the fraction containing PAHs plus S-PACs with 4-7 rings accounted for about 68.2% of the total carcinogenicity of flue gas condensate, whereas the fraction containing more polar PACs and higher PAHs accounted for about 54.6%. All other fractions, such as nonaromatic compounds and PACs with 2 and 3 rings, constituting about 70% of the weight of the total condensate, seemed not to be carcinogenic. Only 1.4% of the total carcinogenicity of the flue gas condensate was found to be attributable to the amount of benzo(a)pyrene (CAS: 50-32-8) present in the condensate (1.14 mg/g condensate). The contribution of more than 100% of both active fractions to the total carcinogenicity (68.2 and 54.6%) may suggest an interrelation of the fractions.

  16. Instabilities and vortex-lattice formation in rotating conventional and dipolar dilute-gas Bose-Einstein condensates

    NASA Astrophysics Data System (ADS)

    Martin, A. M.; Parker, N. G.; van Bijnen, R. M. W.; Dow, A.; O'Dell, D. H. J.

    2008-03-01

    A theoretical study of vortex-lattice formation in atomic Bose-Einstein condensates confined by a rotating elliptical trap is presented. For the conventional case of purely s-wave interatomic interactions, this is done through a consideration of both hydrodynamic equations and time-dependent simulations of the Gross-Pitaevskii equation. We discriminate three distinct, experimentally testable regimes of instability: ripple, interbranch, and catastrophic. Additionally, we generalize the classical hydrodynamical approach to include long-range dipolar interactions, showing how the static solutions and their stability in the rotating frame are significantly altered. This enables us to examine the routes towards unstable dynamics, which, in analogy to conventional condensates, may lead to vortex-lattice formation.

  17. Kinetic Theory of Evaporation and Condensation

    Microsoft Academic Search

    Yoshio Sone; Yoshimoto Onishi

    1973-01-01

    The behavior of a gas in contact with its condensed phase is considered on the basis of a relaxation model of the linearized Boltzmann equation. The temperature and density distributions of the gas in the Knudsen layer as well as so called slip boundary condition on the interface of the gas and its condensed phase are obtained.

  18. 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.

  19. Desulfovibrio carbinoliphilus sp. nov., a benzyl alcohol-oxidizing, sulfate-reducing bacterium isolated from a gas condensate-contaminated aquifer.

    PubMed

    Allen, Toby D; Kraus, Paul F; Lawson, Paul A; Drake, Gwendolyn R; Balkwill, David L; Tanner, Ralph S

    2008-06-01

    Phenotypic and phylogenetic studies were performed on a novel sulfate-reducing bacterium, strain D41(T), isolated as part of a methanogenic syntrophic culture from a gas condensate-contaminated aquifer undergoing intrinsic bioremediation. The bacterium was a Gram-negative, non-spore-forming, curved rod, motile by a single polar flagellum, which oxidized several alcohols incompletely, including methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 3-methyl-1-butanol (isoamyl alcohol), ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, phenylethanol and benzyl alcohol. Additionally, the strain oxidized H(2)/CO(2), formate, lactate, pyruvate, maleate, malate and fumarate. Sulfate, thiosulfate and sulfite were used as electron acceptors. The DNA G+C content was 63 mol%. Based on phylogenetic and phenotypic evidence, the novel species Desulfovibrio carbinoliphilus sp. nov. is proposed. The type strain is D41(T) (=ATCC BAA-1241(T) =DSM 17524(T)). PMID:18523171

  20. Standard for Inert Cryogenic Liquid Usage in the Laboratory Page 1 of 4 Standard for Inert Cryogenic Liquid Usage in the Laboratory

    E-print Network

    Chan, Hue Sun

    safety precautions to be taken when working with inert cryogenics, and is based on standard industry_______________________________________________________________________ Standard for Inert Cryogenic Liquid Usage in the Laboratory Page 1 of 4 March 2009 Standard for Inert Cryogenic Liquid Usage

  1. Performance analysis of compositional and modified black-oil models for rich gas condensate reservoirs with vertical and horizontal wells

    E-print Network

    Izgec, Bulent

    2004-09-30

    drain hole lengths were used. Contrary to the common belief that oil-gas ratio versus depth initialization gives better representation of original fluids in place, initializations with saturation pressure versus depth gave closer original fluids...

  2. Vertical composition gradient effects on original hydrocarbon in place volumes and liquid recovery for volatile oil and gas condensate reservoirs

    E-print Network

    Jaramillo Arias, Juan Manuel

    2000-01-01

    Around the world, volatile oil and retrograde gas reservoirs are considered as complex thermodynamic systems and even more when they exhibit vertical composition variations. Those systems must be characterized by an equation of state (EOS...

  3. A modified Paschen law for the initiation of a dc glow discharge in inert gases

    Microsoft Academic Search

    V. A. Lisovskii; S. D. Yakovin

    2000-01-01

    Breakdown of inert gases in a homogeneous dc electric field is studied experimentally and theoretically at various distances\\u000a L between the electrodes and radii R of the discharge tubes. It is shown that, for arbitrary geometric dimensions of the discharge chamber and cathode materials,\\u000a the ratio of the breakdown electric field strength to the gas pressure holds constant at the

  4. CCl 4 Decomposition in RF Thermal Plasma in Inert and Oxidative Environments

    Microsoft Academic Search

    Tamás Kovács; Tamás Turányi; János Szépvölgyi

    2010-01-01

    The decomposition of carbon tetrachloride was investigated in an RF inductively coupled thermal plasma reactor in inert CCl4–Ar and in oxidative CCl4–O2–Ar systems, respectively. The exhaust gases were analyzed by gas chromatography-mass spectrometry. The kinetics of CCl4 decomposition at the experimental conditions was modeled in the temperature range of 300–7,000 K. The simulations predicted\\u000a 67.0 and 97.9% net conversions of CCl4

  5. Inerting Aircraft Fuel Systems Using Exhaust Gases

    NASA Technical Reports Server (NTRS)

    Hehemann, David G.

    2002-01-01

    Our purpose in this proposal was to determine the feasibility of using carbon dioxide, possibly obtained from aircraft exhaust gases as a substance to inert the fuel contained in fuel tanks aboard aircraft. To do this, we decided to look at the effects carbon dioxide has upon commercial Jet-A aircraft fuel. In particular, we looked at the solubility of CO2 in Jet-A fuel, the pumpability of CO2-saturated Jet-A fuel, the flashpoint of Jet-A fuel under various mixtures of air and CO2, the static outgassing of CO2-Saturated Jet-A fuel and the dynamic outgassing of Jet-A fuel during pumping of Jet-A fuel.

  6. Resonance-inert stabilization for space stations

    NASA Technical Reports Server (NTRS)

    Vonpragenau, G. L.

    1972-01-01

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

  7. Metabolically stable cellular adhesion to inert surfaces.

    PubMed

    Meldal, Morten; Wu, Boqian; Diness, Frederik; Michael, Roice; Hagel, Grith

    2011-11-01

    The structure of D-amino acid hexapeptides that promote cellular adhesion was determined by screening D-amino acid hexapeptide libraries synthesized on otherwise inert beaded PEGA resin. These new adhesion molecules provide a completely stable cellular environment and facilitate the maintenance of a monolayer of cells on beads for extended periods. The presence of the peptides promotes spreading of the cells on the bead surface. Not surprisingly, the molecules contained a significant number of arginines and/or lysines. However, the exact structure of each peptide is quite important for the degree of adhesion observed, and a motif with three or four basic amino acids spaced within amino acids of intermediate polarity clearly prevailed, for example, k-l/r-h-r-i/v-r-a; this maintains a polar/hydrophobic balance. PMID:21928441

  8. Supplemental Information The potential for organic compounds to partition from the gas phase to the condensed phase

    E-print Network

    Meskhidze, Nicholas

    . As an example, we calculate July 2003 averages for aqueous partitioned organic aerosol concentrations Supplemental Information The potential for organic compounds to partition from the gas phase that arise when a simplified Henry's Law approach is used. Equation S1 Where: CJ

  9. Mathematical model of self-sustaining combustion in inert porous medium with phase change under complex heat transfer

    Microsoft Academic Search

    R. Echigo; H. Yoshida

    1998-01-01

    The phenomenon of self-sustaining combustion of a gaseous mixture in inert high porous medium with prior vaporization of liquid droplets is studied by means of a numerical simulation. The complex heat transfer includes convective, conductive and radiative heat transfer between three phases: gas, solid and liquid. Evaporation and different modes of convective heat transfer between liquid, gaseous and solid phases

  10. Electrolytic production of high purity aluminum using inert anodes

    DOEpatents

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

    2001-01-01

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

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

    DOEpatents

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

    2002-01-01

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

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

    E-print Network

    Florida, University of

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

  13. Molecular hydrogen: An inert gas turns clinically effective.

    PubMed

    Ostojic, Sergej M

    2015-06-01

    Molecular hydrogen (H2) appeared as an experimental agent in biomedicine approximately 40 years ago, yet the past 5 years seem to confirm its medicinal value in the clinical environment. H2 improves clinical end-points and surrogate markers in several clinical trials, from metabolic diseases to chronic systemic inflammatory disorders to cancer. However, less information is available concerning its medicinal properties, such as dosage and administration, or adverse reactions and use in specific populations. The present paper overviews the clinical relevance of molecular hydrogen, and summarizes data from clinical trials on this innovative medical agent. Clinical profiles of H2 provide evidence-based direction for practical application and future research on molecular hydrogen for the wider health care community. PMID:25936365

  14. High Pressure Spark Gap in an Inert Gas

    Microsoft Academic Search

    F. J. Jervis-Smith

    1909-01-01

    FOR some years I have employed a high-pressure spark-gap, such as that described by me in the Phil. Mag. for August, 1902, in connection with a Tesla inductive system, and I have experienced considerable trouble arising from the erosion of the spark balls and their supports. They soon become coated with an oxide of the metal employed, and the sparking

  15. Infinite dilution activity coefficient measurements by inert gas stripping method

    Microsoft Academic Search

    Piia Haimi; Petri Uusi-Kyyny; Juha-Pekka Pokki; Juhani Aittamaa; Kari I. Keskinen

    2006-01-01

    The values of activity coefficients at infinite dilution (??) are of especially significance in the reliable design of thermal separation processes producing pure compounds. The ?? has been determined for six branched ethers and four sulfur compounds in water using the dilutor technique. The measurements were carried out in the temperature range from 288 to 333K.

  16. Inert Welding/Brazing Gas Filters and Dryers

    NASA Technical Reports Server (NTRS)

    Goudy, Jerry

    2009-01-01

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

  17. Dynamics and evolution of SO2 gas condensation around Prometheus-like volcanic plumes on Io as seen by the Near Infrared Mapping Spectrometer

    NASA Astrophysics Data System (ADS)

    Douté, S.; Lopes-Gautier, R.; Smythe, W. D.; Kamp, L. W.; Carlson, R.; Galileo NIMS Team

    2000-12-01

    In October 1999, November 1999 and February 2000, Galileo accomplished three successful flybys (I24, I25, I27) of Io, during which the Near Infrared Mapping Spectrometer (NIMS) made local as well as regional observations. Spectral image cubes of active volcanic centers (e.g. Prometheus, Amirani etc. ) and areas targeted for their unique colorimetry were obtained with variable spatial resolution (from 6 km/pixel-1 to 26 km/pixel-1). Most NIMS spectra (from 1.0 ? m to 4.5 ? m) display two prominent and broad features centered respectively at 1.2 ? m and 4.13 ? m. The latter absorption is attributed to frosts of sulfur dioxide (SO2). In an effort to understand the dynamics and evolution of gas condensation around volcanic plumes, we present maps of SO2 abundance and granularity on the surface around Prometheus and Amirani. Reduction of NIMS spectral sampling (from 408 to 14 wavelengths) during the flybys prevents direct modeling of spectra using a bidirectional reflectance model (Douté et al., 2000). Nevertheless, comparison between an I24 global observation with previous SO2 abundance and granularity maps covering 3/4 of Io's surface indicates good correlation between two spectral ratios: ? ={R}obs}(3.28)/{R}{obs(4.13), ? ={R}obs}(3.28)/{R}{obs(3.56) and, respectively, the areal abundance of the frost fSO{2} and its mean grain size DSO{2}. We use a derivative of a classical reflectance model to quantify these dependencies and to invert the data. As a result, maps of SO2 abundance and granularity are obtained which can be correlated to distinguish four different physical units. The distribution of these SO2 units indicates zones of condensation, metamorphism and sublimation linked with the dynamics of volcanic gases, thermal emission and solar flux. This work is supported by a contract with NASA through the Jupiter System Data Analysis Program.

  18. Porous magnesium carboxylate framework: synthesis, X-ray crystal structure, gas adsorption property and heterogeneous catalytic aldol condensation reaction.

    PubMed

    Saha, Debraj; Sen, Rupam; Maity, Tanmoy; Koner, Subratanath

    2012-06-28

    A new three-dimensional alkaline-earth metal-organic framework (MOF) compound, [Mg(Pdc)(H(2)O)](n) (1) (H(2)Pdc = pyridine-2,5-dicarboxylic acid), has been synthesized and structurally characterized by single crystal X-ray diffraction analysis. Compound 1 features a 3D porous framework afforded by the Mg(2)-diad centers through formation of interconnected chair like structural motifs. A nitrogen adsorption study confirms the microporosity of compound 1 with a BET surface area of 211 ± 12 m(2) g(-1). Upon dehydration, the BET surface area of 1 is enhanced to a value of 463 ± 36 m(2) g(-1) due to removal of coordinated water molecule. After rehydration, the compound reverts to its original form as evidenced by powder X-ray diffraction and IR spectroscopic analysis and N(2) sorption measurement. Compound 1 retains its pore structure with a variable BET surface area in several cycles of dehydration and rehydration processes indicating robustness of the framework in [Mg(Pdc)(H(2)O)](n) (1). Compound 1 catalyzes the aldol condensation reactions of various aromatic aldehydes with acetone and cyclohexanone in heterogeneous conditions. Notably, the catalytic activity of the compound is enhanced upon dehydration. The catalyst can be recycled and reused several times without significant loss of activity. PMID:22584602

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

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

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

  1. Use of an inert drilling fluid to control geothermal drill pipe corrosion

    SciTech Connect

    Caskey, B.C.

    1981-04-01

    The results of a geothermal drill pipe corrosion field test are presented. When a low-density drilling fluid was required for drilling a geothermal well because of an underpressured, fractured formation, two drilling fluids were alternatively used to compare drill pipe corrosion rates. The first fluid was an air-water mist with corrosion control chemicals. The other fluid was a nitrogen-water mist without added chemicals. The test was conducted during November 1980 at the Baca Location in northern New Mexico, USA. Data from corrosion rings, corrosion probes, fluid samples, and flow line instrumentation are plotted for the ten day test period. It is shown that the inert drilling fluid (nitrogen) reduced corrosion rates by more than an order of magnitude. Test setup and procedures are also discussed. Development of an on-site inert gas generator could reduce the cost of drilling geothermal wells by extending drill pipe life and reducing corrosion control chemical costs.

  2. Extinguishment of methane diffusion flames by inert gases in coflow air and oxygen-enriched microgravity environments

    Microsoft Academic Search

    Fumiaki Takahashi; Gregory T. Linteris; Viswanath R. Katta

    2011-01-01

    Extinguishment of laminar coflow diffusion flames in microgravity (?g) have been studied experimentally and computationally. The ?g experiments were conducted using a methane cup-burner flame aboard the NASA Reduced-Gravity Aircraft. Transient computations with full methane chemistry and a gray-gas radiation model were performed to reveal the flame structure and extinguishment processes. In ?g, as an inert gas (N2, He, or

  3. 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.

  4. 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. ?* <-- ? excitations are responsible for these strong UV absorptions, but these molecules also possess excited states formed from ?* <-- ? electron promotions. ?? * 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 (?? *-state mediated) ring opening of heterocyclic molecules like furans and thiophenes. Funding from EPSRC (EP/G00224X and EP/L005913) is gratefully acknowledged.

  5. 75 FR 7560 - Public Availability of Identities of Inert Ingredients in Pesticides; Extension of Comment Period

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-22

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

  6. The condensation with partial isolation model of condensation in the solar nebula

    Microsoft Academic Search

    Michail I. Petaev; John A. Wood

    1998-01-01

    We have developed a nebular condensation model and a computational routine that potentially can account for the unequilibrated mineral assemblages in chondritic meteorites. The model assumes that as condensation proceeds a specified fraction (called the isolation degree, x) of the existing condensate is steadily withdrawn from reactive contact with the residual gas, presumably as a result of the growth and

  7. 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.

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

    SciTech Connect

    JEPPSON, D.W.

    2000-05-18

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

  9. Mechanical behaviour of macro-dispersed inert matrix fuels

    Microsoft Academic Search

    E. A. C. Neeft; K. Bakker; R. L. Belvroy; W. J. Tams; R. P. C. Schram; R. Conrad; A. van Veen

    2003-01-01

    Macro-dispersed inert matrix fuels were irradiated in the high flux reactor in Petten. These fuels consisted of UO2 inclusions embedded in the inert matrices MgO, MgAl2O4, Y3Al5O12, CeO2-x and Y2O3. The uranium burn-up reached 17.1–19.8% FIMA after an irradiation period of 198.9 days. The sample temperature was about 700–1000 K. Room temperature indentation measurements were performed in the inert matrices

  10. 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 ?m) 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.

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

    SciTech Connect

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

    1990-05-01

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

  12. Inertance Tube Modeling and the Effects of Temperature

    NASA Astrophysics Data System (ADS)

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

    2010-04-01

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

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

    NASA Astrophysics Data System (ADS)

    Ghosh, Somnath; Friedrich, Rainer

    2015-05-01

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

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

    DOEpatents

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

    1994-01-01

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

  15. Optimisation of inert matrix fuel concepts for americium transmutation

    Microsoft Academic Search

    N. Chauvin; R. J. M Konings; Hj Matzke

    1999-01-01

    Concepts of inert-matrix fuels for americium transmutation are discussed. It is demonstrated that a `hybrid' fuel design, consisting in a dispersion of an americium-bearing phase in an inert matrix, is desirable. More than a solid-solution is preferred in order to localise within a small volume the damage in the matrix due to fission fragments. Such a dispersion is composed of

  16. 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.

  17. Exhaust gas treatment in testing nuclear rocket engines

    SciTech Connect

    Zweig, H.R.; Fischler, S.; Wagner, W.R. (Rocketdyne Division, Rockwell International Corporation, 6633 Canoga Avenue, P.O. Box 7922, Canoga Park, California 91309-7922 (United States))

    1993-01-15

    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.

  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. 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.

  20. 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 ?m 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

  1. Dark matter with topological defects in the Inert Doublet Model

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    We examine the production of dark matter by decaying topological defects in the high mass region mDM gg mW of the Inert Doublet Model, extended with an extra U(1) gauge symmetry. The density of dark matter states (the neutral Higgs states of the inert doublet) is determined by the interplay of the freeze-out mechanism and the additional production of dark matter states from the decays of topological defects, in this case cosmic strings. These decays increase the predicted relic abundance compared to the standard freeze-out only case, and as a consequence the viable parameter space of the Inert Doublet Model can be widened substantially. In particular, for a given dark matter annihilation rate lower dark matter masses become viable. We investigate the allowed mass range taking into account constraints on the energy injection rate from the diffuse ?-ray background and Big Bang Nucleosynthesis, together with constraints on the dark matter properties coming from direct and indirect detection limits. For the Inert Doublet Model high-mass region, an inert Higgs mass as low as ~ 200 GeV is permitted. There is also an upper limit on string mass per unit length, and hence the symmetry breaking scale, from the relic abundance in this scenario. Depending on assumptions made about the string decays, the limits are in the range 1012 GeV to 1013 GeV.

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

    SciTech Connect

    P. McIntyre and S. Seshadri

    2008-06-20

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

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

    NASA Astrophysics Data System (ADS)

    Wallenius, J.

    2003-07-01

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

  4. Inorganic ammonium salts and carbonate salts are efficient catalysts for aldol condensation in atmospheric aerosols.

    PubMed

    Nozière, Barbara; Dziedzic, Pawel; Córdova, Armando

    2010-04-21

    In natural environments such as atmospheric aerosols, organic compounds coexist with inorganic salts but, until recently, were not thought to interact chemically. We have recently shown that inorganic ammonium ions, NH(4)(+), act as catalysts for acetal formation from glyoxal, a common atmospheric gas. In this work, we report that inorganic ammonium ions, NH(4)(+), and carbonate ions, CO(3)(2-), are also efficient catalysts for the aldol condensation of carbonyl compounds. In the case of NH(4)(+) this was not previously known, and was patented prior to this article. The kinetic results presented in this work show that, for the concentrations of ammonium and carbonate ions present in tropospheric aerosols, the aldol condensation of acetaldehyde and acetone could be as fast as in concentrated sulfuric acid and might compete with their reactions with OH radicals. These catalytic processes could produce significant amounts of polyconjugated, light-absorbing compounds in aerosols, and thus affect their direct forcing on climate. For organic gases with large Henry's law coefficients, these reactions could also result in a significant uptake and in the formation of secondary organic aerosols (SOA). This work reinforces the recent findings that inorganic salts are not inert towards organic compounds in aerosols and shows, in particular, that common ones, such as ammonium and carbonate salts, might even play important roles in their chemical transformations. PMID:20358081

  5. Biotreatment of UCG waste water condensate. [Underground coal gasification

    Microsoft Academic Search

    Humenick

    1984-01-01

    The process of underground coal gasification generates a waste water stream during the cooling and processing of the product gas. The character of the UCG condensate is similar to that produced by surface gasifiers, although there are some differences. The treatment options studied in this laboratory project were activated sludge treatment of raw condensate, activated sludge treatment of stripped condensate,

  6. Dark Matter with Two Inert Doublets plus One Higgs Doublet

    E-print Network

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

    2014-08-14

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

  7. A NOVEL INERT COLLAGEN MATRIX FOR HYPOSPADIAS REPAIR

    Microsoft Academic Search

    ANTHONY ATALA; LUIS GUZMAN; ALAN B. RETIK

    1999-01-01

    PurposeIn select patients with hypospadias in whom genital skin is insufficient alternative tissues are needed for urethral reconstruction. Although skin and mucosal grafts may be used, they may increase hospitalization and morbidity. We explored the feasibility of using a bladder submucosal, collagen based inert matrix as a free graft substitute for urethral repair.

  8. Are aromatic diluents used in pyrolysis experiments inert

    Microsoft Academic Search

    Phillip E. Savage

    1994-01-01

    Hydrogen abstraction from compounds such as benzene and biphenyl is a potential complication when these aromatics are used as diluents in hydrocarbon pyrolysis experiments. This paper presents a general methodology for quantitatively assessing the likelihood that substrate-derived radicals abstract hydrogen from a nominally inert diluent. The key variables are the concentration of the substrate, the pyrolysis temperature, and the dissociation

  9. Combustion of hydrocarbon fuels within porous inert media

    Microsoft Academic Search

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

    1996-01-01

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

  10. The Refractive Indices and Verdet Constants of the Inert Gases

    Microsoft Academic Search

    A. Dalgarno; A. E. Kingston

    1960-01-01

    A method is suggested by which the refractive index and Verdet constant of an atomic system may be derived theoretically. It is applied to atomic hydrogen and to the inert gases and a comparison is made with experimental data. The Verdet constant of neon is not anomalous. The origin of the suggestion appears to be an underestimate of the experimental

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

    ERIC Educational Resources Information Center

    Searle, Graeme H.

    1985-01-01

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

  12. A Limit Theorem for Financial Markets with Inert Investors

    Microsoft Academic Search

    Erhan Bayraktar; Ulrich Horst; Ronnie Sircar

    2007-01-01

    We study the effect of investor inertia on stock price fluctuations with a market microstructure model comprising many small investors who are inactive most of the time. It turns out that semi-Markov processes are tailor made for modelling inert investors. With a suitable scaling, we show that when the price is driven by the market imbalance, the log price process

  13. Film Condensation with and Without Body Force in Boundary-Layer Flow of Vapor Over a Flat Plate

    NASA Technical Reports Server (NTRS)

    Chung, Paul M.

    1961-01-01

    Laminar film condensation under the simultaneous influence of gas-liquid interface shear and body force (g force) is analyzed over a flat plate. Important parameters governing condensation and heat transfer of pure vapor are determined. Mixtures of condensable vapor and noncondensable gas are also analyzed. The conditions under which the body force has a significant influence on condensation are determined.

  14. 75 FR 30300 - Restricting the Mailing of Replica or Inert Explosive Devices

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-01

    ...devices, such as simulated grenades that are not dangerous but bear a realistic appearance to explosive devices, to Registered Mail...Inert Explosive Devices Replica or inert explosive devices that bear a realistic appearance to explosive devices such as...

  15. Bose–Einstein condensation in dilute atomic gases: atomic physics meets condensed matter physics

    Microsoft Academic Search

    W. Ketterle

    2000-01-01

    Bose–Einstein condensed atomic gases are a new class of quantum fluids. They are produced by cooling a dilute atomic gas to nanokelvin temperatures using laser and evaporative cooling techniques. The study of these quantum gases has become an interdisciplinary field of atomic and condensed matter physics. Topics of many-body physics can now be studied with the methods of atomic physics.

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

    PubMed

    Chandrasekaran, Sriraam R; Hopke, Philip K

    2012-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-06-01

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

  18. 75 FR 282 - Restricting the Mailing of Replica or Inert Explosive Devices

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-05

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

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

    DOEpatents

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

    2000-01-01

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

  20. Gas mixtures for spark gap closing switches

    DOEpatents

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

    1987-02-20

    Gas mixtures for use in spark gap closing switches comprised of fluorocarbons and low molecular weight, inert buffer gases. To this can be added a third gas having a low ionization potential relative to the buffer gas. The gas mixtures presented possess properties that optimized the efficiency spark gap closing switches. 6 figs.

  1. Gas mixtures for spark gap closing switches

    DOEpatents

    Christophorou, Loucas G. (Oak Ridge, TN); McCorkle, Dennis L. (Knoxville, TN); Hunter, Scott R. (Oak Ridge, TN)

    1988-01-01

    Gas mixtures for use in spark gap closing switches comprised of fluorocarbons and low molecular weight, inert buffer gases. To this can be added a third gas having a low ionization potential relative to the buffer gas. The gas mixtures presented possess properties that optimized the efficiency spark gap closing switches.

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

    NASA Astrophysics Data System (ADS)

    Cornell, Eric A.

    1997-04-01

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

  3. Inert scalars and vacuum metastability around the electroweak scale

    E-print Network

    Bogumila Swiezewska

    2015-03-24

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

  4. Inert scalars and vacuum metastability around the electroweak scale

    E-print Network

    Swiezewska, Bogumila

    2015-01-01

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

  5. The Electroweak Phase Transition in the Inert Doublet Model

    E-print Network

    Blinov, Nikita; Stefaniak, Tim

    2015-01-01

    We study the strength of a first-order electroweak phase transition in the Inert Doublet Model (IDM), where particle dark matter (DM) is comprised of the lightest neutral inert Higgs boson. We improve over previous studies in the description and treatment of the finite-temperature effective potential and of the electroweak phase transition. We focus on a set of benchmark models inspired by the key mechanisms in the IDM leading to a viable dark matter particle candidate, and illustrate how to enhance the strength of the electroweak phase transition by adjusting the masses of the yet undiscovered IDM Higgs states. We argue that across a variety of DM masses, obtaining a strong enough first-order phase transition is a generic possibility in the IDM. We find that due to direct dark matter searches and collider constraints, a sufficiently strong transition and a thermal relic density matching the universal DM abundance is possible only in the Higgs funnel regime.

  6. Significant gamma lines from inert Higgs dark matter.

    PubMed

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

    2007-07-27

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

  7. Inert matrix fuel in dispersion type fuel elements

    Microsoft Academic Search

    A. M. Savchenko; A. V. Vatulin; A. V. Morozov; V. L. Sirotin; I. V. Dobrikova; G. V. Kulakov; S. A. Ershov; V. P. Kostomarov; Y. I. Stelyuk

    2006-01-01

    The advantages of using inert matrix fuel (IMF) as a dispersion fuel in an aluminium alloy matrix are considered, in particular, low temperatures in the fuel centre, achievable high burn-ups, serviceability in transients and an environmentally friendly process of fuel rod fabrication. Two main versions of IMF are under development at A.A. Bochvar Institute, i.e. heterogeneous or isolated distribution of

  8. Evolution of weak disturbances in inert binary mixtures

    NASA Technical Reports Server (NTRS)

    Rasmussen, M. L.

    1977-01-01

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

  9. Metal ion implantation in inert polymers for strain gauge applications

    Microsoft Academic Search

    Giovanni Di Girolamo; Marcello Massaro; Emanuela Piscopiello; Leander Tapfer

    2010-01-01

    Metal ion implantation in inert polymers may produce ultra-thin conducting films below the polymer surface. These subsurface films are promising structures for strain gauge applications. To this purpose, polycarbonate substrates were irradiated at room temperature with low-energy metal ions (Cu+ and Ni+) and with fluences in the range between 1×1016 and 1×1017ions\\/cm2, in order to promote the precipitation of dispersed

  10. 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.

  11. Enhanced Condensation Heat Transfer

    NASA Astrophysics Data System (ADS)

    Rose, John Winston

    The paper gives some personal observations on various aspects of enhanced condensation heat transfer. The topics discussed are external condensation (horizontal low-finned tubes and wire-wrapped tubes), internal condensation (microfin tubes and microchannels) and Marangoni condensation of binary mixtures.

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

    PubMed Central

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

    2014-01-01

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

  13. Neutrophils generate microparticles during exposure to inert gases due to cytoskeletal oxidative stress.

    PubMed

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

    2014-07-01

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

  14. Rare-gas solids in the Earth's deep interior

    NASA Astrophysics Data System (ADS)

    Jephcoat, Andrew P.

    1998-05-01

    Chemical inertness and surface volatility, combined with low abundance, have made the rare (noble) gases a unique trace-elemental and isotopic system for constraining the formation and evolution of the solid Earth and its atmosphere. Here I examine the implications of recent high-pressure measurements of the melting temperatures of heavy rare-gas solids-argon, krypton and xenon-with new diamond-anvil cell methods, together with their pressure-volume relationship, for the total rare-gas inventory of the Earth since its formation. The solid-liquid (melting) transition in these rare-gas solids rises significantly with pressure in the 50GPa range,, such that melting temperatures will exceed the geotherm at pressures of the Earth's transition zone and lower mantle (depths greater than 410-670km). The densities of condensed rare-gas solids obtained from recent pressure-volume measurements at high compressions also exceed Earth's mantle and core densities. These pressure-induced changes in the physical properties of rare-gas solids, combined with their expected low solubilities and diffusional growth mechanisms, suggest that dense solid or fluid inclusions of rare gases-initially at nanometre scales-would have formed in the Earth's interior and may have resulted in incomplete planetary degassing. Separation of dense solid inclusions into deeper regions during early planet formation could provide a straightforward explanation for the unexpectedly low absolute abundance of xenon observed in the atmospheres of both Earth and Mars.

  15. Macroscopic superpositions of Bose-Einstein condensates

    E-print Network

    Janne Ruostekoski; M. J. Collett; Robert Graham; Dan F. Walls

    1997-08-13

    We consider two dilute gas Bose-Einstein condensates with opposite velocities from which a monochromatic light field detuned far from the resonance of the optical transition is coherently scattered. In the thermodynamic limit, when the relative fluctuations of the atom number difference between the two condensates vanish, the relative phase between the Bose-Einstein condensates may be established in a superposition state by detections of spontaneously scattered photons, even though the condensates have initially well-defined atom numbers. For a finite system, stochastic simulations show that the measurements of the scattered photons lead to a randomly drifting relative phase and drive the condensates into entangled superpositions of number states. This is because according to Bose-Einstein statistics the scattering to an already occupied state is enhanced.

  16. Zirconia Inert Matrix Fuel for Plutonium and Minor Actinides Management in Reactors and as an Ultimate Waste Form

    SciTech Connect

    Degueldre, Claude [NES, PSI, OHLD 08, Villigen, CH-5232 (Switzerland); Wiesenack, Wolfgang [OECD Halden Reactor Project, Halden, 1751 (Norway)

    2008-07-01

    An yttria stabilised zirconia doped with plutonia and erbia has been selected as inert matrix fuel (IMF) at PSI. The results of experimental irradiation tests on yttria-stabilised zirconia doped with plutonia and erbia pellets in the Halden research reactor as well as a study of zirconia solubility are presented. Zirconia must be stabilised by yttria to form a solid solution such as MAz(Y,Er){sub y}Pu{sub x}Zr{sub 1-y}O{sub 2-{xi}} where minor actinides (MA) oxides are also soluble. (Er,Y,Pu,Zr)O{sub 2-{xi}} (with Pu containing 5% Am) was successfully prepared at PSI and irradiated in the Halden reactor. Emphasis is given on the zirconia- IMF properties under in-pile irradiation, on the fuel material centre temperatures and on the fission gas release. The retention of fission products in zirconia may be stronger at similar temperature, compared to UO{sub 2}. The outstanding behaviour of plutonia-zirconia inert matrix fuel is compared to the classical (U,Pu)O{sub 2} fuels. The properties of the spent fuel pellets are presented focusing on the once-through strategy. For this strategy, low solubility of the inert matrix is required for geological disposal. This parameter was studied in detail for a range of solutions corresponding to groundwater under near field conditions. Under these conditions the IMF solubility is about 109 times smaller than glass, several orders of magnitude lower than UO{sub 2} in oxidising conditions (Yucca Mountain) and comparable in reducing conditions, which makes the zirconia material very attractive for deep geological disposal. The behaviour of plutonia-zirconia inert matrix fuel is discussed within a 'burn and bury' strategy. (authors)

  17. Effect of Different Parameters on Synthesis of Moo3 Nano-Powder by Evaporation–Condensation Technique

    Microsoft Academic Search

    S. H. Hosseini; M. Saghafi; S. Heshmati-Manesh

    2012-01-01

    In the present study, MoO3 nano-powder was produced by evaporation of molybdenum oxide powder at high temperature (arround 1000°C), and its subsequent cooling in inert gas. The effect of different parameters such as pressure, temperature and type of inert gas on the morphology and particle size were examined. The samples were characterized in terms of structure, morphology, particle size and

  18. Modeling unit cell interactions for the microstructure of a heterogeneous explosive: detonation diffraction past an inert sphere

    SciTech Connect

    Bdzil, John B [Los Alamos National Laboratory; Stewart, Donald S [Los Alamos National Laboratory; Walter, John W [Los Alamos National Laboratory; Aida, Toru [Los Alamos National Laboratory

    2009-01-01

    We describe an approach being used to model multi-phase blast explosive, that is mostly condensed explosive by volume with inert embedded particles. The asymptotic theory of detonation shock dynamics is used to describe the detonation shock propagation in the explosive. The shock motion rule in the explosive requires that the shock move at a normal speed that depends on the shock curvature. The angle that the shock makes with the particle boundary is also prescribed. We describe theory that can be used to predict the behavior of a collection of such detonation shock/particle interactions in the larger aggregate. A typical unit cell problem of a detonation shock diffraction over a sphere is analyzed by analytical and numerical means and the properties of an ensemble of such unit cell problems is discussed with implications for the macroscopic limiting behavior of the heterogeneous explosive.

  19. Dynamics and Structure of Dusty Reacting Flows: Inert Particles in Strained, Laminar, Premixed Flames

    NASA Technical Reports Server (NTRS)

    Egolfopoulos, Fokion N.; Campbell, Charles S.

    1999-01-01

    A detailed numerical study was conducted on the dynamics and thermal response of inert, spherical particles in strained, laminar, premixed hydrogen/air flames. The modeling included the solution of the steady conservation equations for both the gas and particle phases along and around the stagnation streamline of an opposed-jet configuration, and the use of detailed descriptions of chemical kinetics and molecular transport, For the gas phase, the equations of mass, momentum, energy, and species are considered, while for the particle phase, the model is based on conservation equations of the particle momentum balance in the axial and radial direction, the particle number density, and the particle thermal energy equation. The particle momentum equation includes the forces as induced by drag, thermophoresis, and gravity. The particle thermal energy equation includes the convective/conductive heat exchange between the two phases, as well as radiation emission and absorption by the particle. A one-point continuation method is also included in the code that allows for the description of turning points, typical of ignition and extinction behavior. As expected, results showed that the particle velocity can be substantially different than the gas phase velocity, especially in the presence of large temperature gradients and large strain rates. Large particles were also found to cross the gas stagnation plane, stagnate, and eventually reverse as a result of the opposing gas phase velocity. It was also shown that the particle number density varies substantially throughout the flowfield, as a result of the straining of the flow and the thermal expansion. Finally, for increased values of the particle number density, substantial flame cooling to extinction states and modification of the gas phase fluid mechanics were observed. As also expected, the effect of gravity was shown to be important for low convective velocities and heavy particles. Under such conditions, simulations indicate that the magnitude and direction of the gravitational force can substantially affect the profiles of the particle velocity, number density, mass flux, and temperature.

  20. Dynamics and Structure of Dusty Reacting Flows: Inert Particles in Strained, Laminar, Premixed Flames

    NASA Technical Reports Server (NTRS)

    Egolfopoulos, Fokion N.; Campbell, Charles S.; Wu, Ming-Shin (Technical Monitor)

    1999-01-01

    A detailed numerical study was conducted on the dynamics and thermal response of inert spherical particles in strained, laminar, premixed hydrogen/air flames. The modeling included the solution of the steady conservation equations for both the gas and particle phases along and around the stagnation streamline of an opposed-jet configuration, and the use of detailed descriptions of chemical kinetics and molecular transport. For the gas phase, the equations of mass, momentum, energy, and species are considered, while for the particle phase, the model is based on conservation equations of the particle momentum balance in the axial and radial direction, the particle number density, and the particle thermal energy equation. The particle momentum equation includes the forces as induced by drag, thermophoresis, and gravity. The particle thermal energy equation includes the convective/conductive heat exchange between the two phases, as well as radiation emission and absorption by the particle. A one-point continuation method is also included in the code that allows for the description of turning points, typical of ignition and extinction behavior. As expected, results showed that the particle velocity can be substantially different than the gas phase velocity, especially in the presence of large temperature gradients and large strain rates. Large particles were also found to cross the gas stagnation plane, stagnate, and eventually reverse as a result of the opposing gas phase velocity. It was also shown that the particle number density varies substantially throughout the flowfield, as a result of the straining of the flow and the thermal expansion. Finally, for increased values of the particle number density, substantial flame cooling to extinction states and modification of the gas phase fluid mechanics were observed. As also expected, the effect of gravity was shown to be important for low convective velocities and heavy particles. Under such conditions, simulations indicate that the magnitude and direction of the gravitational force can substantially affect the profiles of the particle velocity, number density, mass flux, and temperature.

  1. Inert Anode Life in Low Temperature Reduction Process

    SciTech Connect

    Bradford, Donald R.

    2005-06-30

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

  2. Inertization of toxic metals in metakaolin-blended cements

    SciTech Connect

    Pera, J.; Bonnin, E. [URGC-Materiaux, Villeurbanne (France)

    1996-12-31

    Three blended cements containing respectively 10, 20, and 30 % metakaolin (MK) were tested for engineering properties and ability to immobilize chromium, lead, and cadmium. The pollutants (sodium bichromate, lead nitrate, and cadmium chloride) were added to the mixing water of pastes and standard mortars. The strength, microstructure and leaching properties of pastes and mortars were investigated. The results obtained show that a binder containing around 20 to 30 % MK is efficient towards the inertization of toxic metals. Some mechanisms of immobilization are proposed : Cr (VI) is incorporated in calcium aluminates while Cd and Pb are fixed in C-S-H.

  3. Clamp and Gas Nozzle for TIG Welding

    NASA Technical Reports Server (NTRS)

    Gue, G. B.; Goller, H. L.

    1982-01-01

    Tool that combines clamp with gas nozzle is aid to tungsten/inert-gas (TIG) welding in hard-to-reach spots. Tool holds work to be welded while directing a stream of argon gas at weld joint, providing an oxygen-free environment for tungsten-arc welding.

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

    PubMed Central

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

    2014-01-01

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

  5. Materials research on inert matrices: a screening study

    NASA Astrophysics Data System (ADS)

    Matzke, Hj; Rondinella, V. V.; Wiss, T.

    1999-08-01

    Materials research on inert matrices for U-free fuels has been extensively performed at the Institute for Transuranium Elements (ITU) for more than five years. Relevant experience, e.g. on MgO-based ceramic fuel, fabrication and irradiation of annular cercer and cermet fuel and of ThO 2-based fuel in ITU dates back to about 30 yr ago. The criteria for selecting inert matrices for Am-transmutation, their fabrication - with and without Am - and typical results on property measurements are discussed, often in comparison with UO 2, with emphasis on radiation damage formation and damage effects. The materials studied in most detail are spinel MgAl 2O 4, zircon ZrSiO 4, ceria CeO 2- x, yttria-stabilized zirconia (Zr 1- xY x)O 2- x/2 , monazite CePO 4, and to a smaller degree Al 2O 3, MgO, SiC and Si 3N 4. This paper mentions and reports significant characteristics and experimental results for some of the above listed materials, as an overview of the research activities carried out at ITU. Preliminary results of first leaching experiments with Am-doped CeO 2, MgAl 2O 4 and ZrSiO 4 are also reported. Some recommendations deduced from this work are summarized.

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

    NASA Astrophysics Data System (ADS)

    Panahi, Allen

    2009-05-01

    On July 18, 2008, the FAA mandated that new aircraft are to include inerting technology to significantly reduce the potential for flammable vapor spaces in center wing fuel tanks. All passenger aircraft constructed since 1991 must also be retrofitted with this technology. This ruling is the result of 18 aircraft that have experienced fuel tank flammable vapor ignition incidents since 1960. Included in these are the TWA 800 and Avianca Flight 203 incidents that resulted in 337 total fatalities. Comprised of heavier hydrocarbon components, jet fuel is much less volatile, with Jet A having a flash point of approximately 100°F and JP-4 having a flash point of approximately 0°F. In contrast, straight-run gasoline has a flash point of approximately -40°F. The flash point is the minimum temperature where a liquid fuel can generate enough vapor to form a flammable mixture with air. If the temperature is below the flash point there isn't enough fuel evaporating to form a flammable fuel-air mixture. Since jet fuel and gasoline have similar flammable concentration limits, gasoline must produce much more vapor at a given temperature to have such a low flash point; hence gasoline is much more volatile than jet fuel. In this paper we explore Fluorescence Technology as applied to the design and development of O2 sensors that can be used for this application and discuss the various test and measurement techniques used to estimate the O2 gas concentration. We compare the various intensity based approaches and contrast them with the frequency domain techniques that measure phase to extract fluorescent lifetimes. The various inerting fuel tank requirements are explained and finally a novel compact measurement system using that uses the frequency heterodyning cross correlation technique that can be used for various applications is described in detail while the benefits are explored together with some test data collected.

  7. Gas

    MedlinePLUS

    ... and pain in the belly—especially after a big meal. Foods that can cause gas Some people naturally produce ... your stomach or throw up . Your breasts are big and sore . The area around your nipples gets darker. You crave certain foods. Or you really dislike certain foods. You feel ...

  8. Thermodynamic simulation of transfer of lead, cadmium, and zinc to the gas phase during oxidative and reductive thermal treatment of coals from some coal deposits of the Russian federation

    SciTech Connect

    L.N. Lebedeva; L.A. Kost; E.G. Gorlov; E.V. Samuilov [FGUP Institute for Fossil Fuels, Moscow (Russian Federation)

    2007-02-15

    The results of thermodynamic study of the distribution of Pb, Cd, and Zn during the thermal processing of coals from the Kuznetsk and Moscow basins and the Berezovskoe coal deposit of the Kansk-Achinsk basin at different excess oxidant (air) factors and in an inert (argon) medium are presented. The equilibrium forms of compounds were revealed, and their concentrations in the gas and condensed phase were calculated. Trace elements get into the gas phase during the heat treatment of coals in both oxidizing and reducing media. Their most intense transfer to the gas phase takes place at a = 0.4. An increase in temperature enhances this process, and an increase in the ash content of coal decreased the extent of transfer. 9 refs., 10 tabs.

  9. Economical Condensing Turbines? 

    E-print Network

    Dean, J. E.

    1997-01-01

    Steam turbines have long been used at utilities and in industry to generate power. There are three basic types of steam turbines: condensing, letdown and extraction/condensing. • Letdown turbines reduce the pressure of the incoming steam to one...

  10. Condensed Matter Physics

    Microsoft Academic Search

    Michael P. Marder

    2000-01-01

    A modern, unified treatment of condensed matter physics This new work presents for the first time in decades a sweeping review of the whole field of condensed matter physics. It consolidates new and classic topics from disparate sources, teaching \\

  11. In situ observation of sub-Poissonian atom-number fluctuations in a repulsive 1D Bose gas: quantum quasi-condensate and strongly interacting regimes

    E-print Network

    In situ observation of sub-Poissonian atom-number fluctuations in a repulsive 1D Bose gas: quantum for Quantum-Atom Optics, School of Mathematics and Physics, University of Queensland, Brisbane, Queensland 4072, Australia (Dated: March 21, 2011) We report on local measurements of atom number fluctuations

  12. Attosecond spectroscopy in condensed matter

    NASA Astrophysics Data System (ADS)

    Cavalieri, A. L.; Müller, N.; Uphues, Th.; Yakovlev, V. S.; Baltuška, A.; Horvath, B.; Schmidt, B.; Blümel, L.; Holzwarth, R.; Hendel, S.; Drescher, M.; Kleineberg, U.; Echenique, P. M.; Kienberger, R.; Krausz, F.; Heinzmann, U.

    2007-10-01

    Comprehensive knowledge of the dynamic behaviour of electrons in condensed-matter systems is pertinent to the development of many modern technologies, such as semiconductor and molecular electronics, optoelectronics, information processing and photovoltaics. Yet it remains challenging to probe electronic processes, many of which take place in the attosecond (1as = 10-18s) regime. In contrast, atomic motion occurs on the femtosecond (1fs = 10-15s) timescale and has been mapped in solids in real time using femtosecond X-ray sources. Here we extend the attosecond techniques previously used to study isolated atoms in the gas phase to observe electron motion in condensed-matter systems and on surfaces in real time. We demonstrate our ability to obtain direct time-domain access to charge dynamics with attosecond resolution by probing photoelectron emission from single-crystal tungsten. Our data reveal a delay of approximately 100attoseconds between the emission of photoelectrons that originate from localized core states of the metal, and those that are freed from delocalized conduction-band states. These results illustrate that attosecond metrology constitutes a powerful tool for exploring not only gas-phase systems, but also fundamental electronic processes occurring on the attosecond timescale in condensed-matter systems and on surfaces.

  13. Attosecond spectroscopy in condensed matter.

    PubMed

    Cavalieri, A L; Müller, N; Uphues, Th; Yakovlev, V S; Baltuska, A; Horvath, B; Schmidt, B; Blümel, L; Holzwarth, R; Hendel, S; Drescher, M; Kleineberg, U; Echenique, P M; Kienberger, R; Krausz, F; Heinzmann, U

    2007-10-25

    Comprehensive knowledge of the dynamic behaviour of electrons in condensed-matter systems is pertinent to the development of many modern technologies, such as semiconductor and molecular electronics, optoelectronics, information processing and photovoltaics. Yet it remains challenging to probe electronic processes, many of which take place in the attosecond (1 as = 10(-18) s) regime. In contrast, atomic motion occurs on the femtosecond (1 fs = 10(-15) s) timescale and has been mapped in solids in real time using femtosecond X-ray sources. Here we extend the attosecond techniques previously used to study isolated atoms in the gas phase to observe electron motion in condensed-matter systems and on surfaces in real time. We demonstrate our ability to obtain direct time-domain access to charge dynamics with attosecond resolution by probing photoelectron emission from single-crystal tungsten. Our data reveal a delay of approximately 100 attoseconds between the emission of photoelectrons that originate from localized core states of the metal, and those that are freed from delocalized conduction-band states. These results illustrate that attosecond metrology constitutes a powerful tool for exploring not only gas-phase systems, but also fundamental electronic processes occurring on the attosecond timescale in condensed-matter systems and on surfaces. PMID:17960239

  14. Simulation of condensation systems in the presence of noncondensable gases

    E-print Network

    Raja, Laxminarayan Lakshmana

    1992-01-01

    -LOSS OF RHR TRAN- SIENT 97 VITA 142 LIST OF FIGURES Figure Page 1 Condensation Phenomena in the Presence of a, Noncondensable Gas. . . 4 2 Schematic of U-Tube Condensation Experiment 10 3 RELAP Nodalization of the U-Tube Condensation Experiment . 15 4... hydrodynamic junctions. Twelve kinds of hydrodynamic components are available in RELAP5 to build up a model for a. thermal hydraulic simulation. The combination of these compo- nents facilitate the input data. development process. Five components, single...

  15. Condensation in Microchannels

    Microsoft Academic Search

    Yongping Chen; Mingheng Shi; Ping Cheng; G. P. Peterson

    2008-01-01

    Condensation in microchannels has applications in a wide variety of advanced microthermal devices. Presented here is a review of both experimental and theoretical analyses of condensation in these microchannels, with special attention given to the effects of channel diameter and surface conditions on the flow regimes of condensing flows occurring in these channels. This review suggests that surface tension, rather

  16. Green's-function formalism for a condensed Bose gas consistent with infrared-divergent longitudinal susceptibility and Nepomnyashchii-Nepomnyashchii identity

    NASA Astrophysics Data System (ADS)

    Watabe, Shohei; Ohashi, Yoji

    2014-07-01

    We present a Green's-function formalism for an interacting Bose-Einstein condensate (BEC) satisfying the two required conditions: (i) the infrared-divergent longitudinal susceptibility with respect to the BEC order parameter, and (ii) the Nepomnyashchii-Nepomnyashchii identity stating the vanishing off-diagonal self-energy in the low-energy and low-momentum limit. These conditions cannot be described by the ordinary mean-field Bogoliubov theory, the many-body T-matrix theory, or the random-phase approximation with the vertex correction. In this paper, we show that these required conditions can be satisfied, when we divide many-body corrections into singular and nonsingular parts, and separately treat them as different self-energy corrections. The resulting Green's function may be viewed as an extension of the Popov's hydrodynamic theory to the region at finite temperatures. Our results would be useful in constructing a consistent theory of BECs satisfying various required conditions, beyond the mean-field level.

  17. Chiral condensate in hadronic matter

    NASA Astrophysics Data System (ADS)

    Jankowski, J.; Blaschke, D.; Spali?ski, M.

    2013-05-01

    The finite temperature chiral condensate for 2+1 quark flavors is considered in the framework of the hadron resonance gas model. This requires some dynamical information, for which two models are employed: one based on the quark structure of hadrons combined with the Nambu-Jona-Lasinio approach to chiral symmetry breaking, and one originating from gauge/gravity duality. Using these insights, hadronic sigma terms are discussed in the context of recent first-principles results following from lattice QCD and chiral perturbation theory. For the condensate, in generic agreement with lattice data it is found that chiral symmetry restoration in the strange quark sector takes place at higher temperatures than in the light quark sector. The importance of this result for a recently proposed dynamical model of hadronic freeze-out in heavy ion collisions is outlined.

  18. Low Energy Nuclear Transmutation in Condensed Matter Induced by D2 Gas Permeation Through pd Complexes:. Correlation Between Deuterium Flux and Nuclear Products

    NASA Astrophysics Data System (ADS)

    Iwamura, Y.; Itoh, T.; Sakano, M.; Sakai, S.; Kuribayashi, S.

    2005-12-01

    Observations of low energy nuclear reactions induced by D2 gas permeation through Pd complexes (Pd/CaO/Pd) were presented at ICCF-91 and in a paper2 published in the Japanese Journal of Applied Physics. When Cs was added on the surface of a Pd complex, Pr emerged on the surface while Cs decreased after the Pd complex was subjected to D2 gas permeation. When Sr was added to the surface, Mo emerged while the Sr decreased after D2 gas permeation. The isotopic composition of the detected Mo was different from the natural abundance. In this paper, recent progress of our research is described. The detected Pr was confirmed by various methods such as TOF-SIMS, XANES, X-ray Fluorescence Spectrometry and ICP-MS. Analysis of the depth profile of Pr indicated that a very thin surface region up to 100 Å was the active transmutation zone. Many experimental results showed that the quantity of Pr was proportional to the deuterium flux through Pd complex. The cross-section of transmutation of Cs into Pr can be roughly estimated at 1 barn if we consider the deuterium flux as an ultra low energy deuteron beam.

  19. Condensation Front Migration in a Protoplanetary Nebula

    NASA Technical Reports Server (NTRS)

    Davis, Sanford S.

    2004-01-01

    Condensation front dynamics are investigated in the mid-solar nebula region. A quasi-steady model of the evolving nebula is combined with equilibrium vapor pressure curves to determine evolutionary condensation fronts for selected species. These fronts are found to migrate inwards from the far-nebula to final positions during a period of 10(exp 7) years. The physical process governing this movement is a combination of local viscous heating and luminescent heating from the central star. Two luminescent heating models are used and their effects on the ultimate radial position of the condensation front are discussed. At first the fronts move much faster than the nebular accretion velocity, but after a time the accreting gas and dust overtakes the slowing condensation front.

  20. Are aromatic diluents used in pyrolysis experiments inert

    SciTech Connect

    Savage, P.E. (Univ. of Michigan, Ann Arbor, MI (United States). Chemical Engineering Dept.)

    1994-05-01

    Hydrogen abstraction from compounds such as benzene and biphenyl is a potential complication when these aromatics are used as diluents in hydrocarbon pyrolysis experiments. This paper presents a general methodology for quantitatively assessing the likelihood that substrate-derived radicals abstract hydrogen from a nominally inert diluent. The key variables are the concentration of the substrate, the pyrolysis temperature, and the dissociation energies of the C-H bonds attacked. Hydrogen abstraction from an aromatic diluent becomes more important as the temperature increases, the substrate concentration decreases, and the C-H bond dissociation energy of the substrate increases. All other factors being equal, the relative rate of hydrogen abstraction from an aromatic diluent is about 10 times higher during the pyrolysis of an n-alkane than during the pyrolysis of an n-alkylbenzene.

  1. Drill Pipe Corrosion Control Using an Inert Drilling Fluid

    SciTech Connect

    Caskey, B. C.; Copass, K. S.

    1981-01-01

    The results of a geothermal drill pipe corrosion field test are presented. When a low-density drilling fluid was required for drilling a geothermal well because of an underpressured, fractured formation, two drilling fluids were alternately used to compare drill pipe corrosion rates. The first fluid was an air-water mist with corrosion control chemicals. The other fluid was a nitrogen-water mist without added chemicals. The test was conducted during November 1980 at the Baca location in northern New Mexico. Data from corrosion rings, corrosion probes, fluid samples and flow line instrumentation are plotted for the ten day test period. it is shown that the inert drilling fluid, nitrogen, reduced corrosion rates by more than an order of magnitude. Test setup and procedures are also discussed.

  2. Aerosol Growth and the Condensation Coefficient for Water: A Review

    Microsoft Academic Search

    Michael Mozurkewich

    1986-01-01

    The transfer of gas phase species to aerosols depends critically on the condensation (or sticking) coefficient. Reported values for water on water vary from 0.03 to 1. Theoretical arguments indicate that the condensation coefficient should be near unity for polar species on an aqueous surface. As long as heat transfer is properly accounted for, measurements on bulk water support this

  3. Condensation of water vapor in rarefaction waves. I - Homogeneous nucleation

    Microsoft Academic Search

    J. P. Sislian; I. I. Glass

    1976-01-01

    A detailed theoretical investigation has been made of the condensation of water vapor\\/carrier gas mixtures in the nonstationary rarefaction wave generated in a shock tube. It is assumed that condensation takes place by homogeneous nucleation. The equations of motion together with the nucleation rate and the droplet growth equations were solved numerically by the method of characteristics and Lax's method

  4. Electron-induced damage of biotin studied in the gas phase and in the condensed phase at a single-molecule level

    NASA Astrophysics Data System (ADS)

    Keller, Adrian; Kopyra, Janina; Gothelf, Kurt V.; Bald, Ilko

    2013-08-01

    Biotin is an essential vitamin that is, on the one hand, relevant for the metabolism, gene expression and in the cellular response to DNA damage and, on the other hand, finds numerous applications in biotechnology. The functionality of biotin is due to two particular sub-structures, the ring structure and the side chain with carboxyl group. The heterocyclic ring structure results in the capability of biotin to form strong intermolecular hydrogen and van der Waals bonds with proteins such as streptavidin, whereas the carboxyl group can be employed to covalently bind biotin to other complex molecules. Dissociative electron attachment (DEA) to biotin results in a decomposition of the ring structure and the carboxyl group, respectively, within resonant features in the energy range 0-12 eV, thereby preventing the capability of biotin for intermolecular binding and covalent coupling to other molecules. Specifically, the fragment anions (M-H)-, (M-O)-, C3N2O-, CH2O2-, OCN-, CN-, OH- and O- are observed, and exemplarily the DEA cross section of OCN- formation is determined to be 3 × 10-19 cm2. To study the response of biotin to electrons within a complex condensed environment, we use the DNA origami technique and determine a dissociation yield of (1.1 ± 0.2) × 10-14 cm2 at 18 eV electron energy, which represents the most relevant energy for biomolecular damage induced by secondary electrons. The present results thus have important implications for the use of biotin as a label in radiation experiments.

  5. Theoretical analysis of condensation in the presence of noncondensable gases as applied to open cycle OTEC condensers

    Microsoft Academic Search

    C. B. Panchal; K. J. Bell

    1984-01-01

    The open cycle ocean thermal energy conversion condenser was analyzed from a theoretical standpoint. Interfacial temperature profiles and gas concentrations in the axial direction were determined, and their effects on the rate of condensation studied. For the analysis, the vapor phase was modeled using diffusion equations for simultaneous heat and mass transfer processes, while the liquid phase was modeled using

  6. Gas diffusion cell removes carbon dioxide from occupied airtight enclosures

    NASA Technical Reports Server (NTRS)

    1964-01-01

    Small, lightweight permeable cell package separates and removes carbon dioxide from respiratory gas mixtures. The cell is regenerative while chemically inert in the presence of carbon dioxide so that only adsorption takes place.

  7. Paste Residence Time in a Spouted Bed Dryer. IV: Effect of the Inert Particle Size Distribution

    Microsoft Academic Search

    Luciana A. Tacon; Luis A. P. Freitas

    2011-01-01

    The residence time distribution and mean residence time of a 10% sodium bicarbonate solution that is dried in a conventional spouted bed with inert bodies were measured with the stimulus-response method. Methylene blue was used as a chemical tracer, and the effects of the paste feed mode, size distribution of the inert bodies, and mean particle size on the residence

  8. The Ethics of Placebo-controlled Trials: A Comparison of Inert and Active Placebo Controls

    Microsoft Academic Search

    Sarah J. L. Edward; Andrew J. Stevens; David A. Braunholtz; Richard J. Lilford; Teresa Swift

    2005-01-01

    Because of the recent and controversial example of sham surgery for the evaluation of fetal tissue transplants for Parkinson’s disease, there is renewed interest in the ethics of using “active” placebos in surgical trials, where otherwise there are no inert procedures available, and in pharmacological trials, where there are inert substances, but where patients may guess to which arm they

  9. 30 CFR 75.1107-12 - Inerting of mine atmosphere prohibited.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Inerting of mine atmosphere prohibited. 75.1107-12 Section 75.1107-12 Mineral...Underground Equipment § 75.1107-12 Inerting of mine atmosphere prohibited. No fire suppression device designed to...

  10. 30 CFR 75.1107-12 - Inerting of mine atmosphere prohibited.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Inerting of mine atmosphere prohibited. 75.1107-12 Section 75.1107-12 Mineral...Underground Equipment § 75.1107-12 Inerting of mine atmosphere prohibited. No fire suppression device designed to...

  11. 30 CFR 75.1107-12 - Inerting of mine atmosphere prohibited.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Inerting of mine atmosphere prohibited. 75.1107-12 Section 75.1107-12 Mineral...Underground Equipment § 75.1107-12 Inerting of mine atmosphere prohibited. No fire suppression device designed to...

  12. 30 CFR 75.1107-12 - Inerting of mine atmosphere prohibited.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Inerting of mine atmosphere prohibited. 75.1107-12 Section 75.1107-12 Mineral...Underground Equipment § 75.1107-12 Inerting of mine atmosphere prohibited. No fire suppression device designed to...

  13. SIMULATION OF DRYING SUSPENSIONS IN SPOUT-FLUID BEDS OF INERT PARTICLES

    Microsoft Academic Search

    E. F. Costa Jr; M. Cardoso; M. L. Passos

    2001-01-01

    In spouted and spout fluid bed dryers, the suspension is spread into the bed of inert particles, covering these particles with a thin layer. As the inert particles circulate, this suspension layer is dried and must become brittle enough to break off by the particle attrition. The powder produced is then carried out by air. Problems with the spout stability,

  14. Laminar radial flow electrochemical reactors. II. Convective diffusion of inert tracer

    Microsoft Academic Search

    F. B. Thomas; P. A. Ramachandran; M. P. Dudukovic; R. E. W. Jansson

    1989-01-01

    Mixing is investigated in three laminar radial flow cells (capillary gap cell (stationary discs), pump cell (one disc spinning) and the rotating electrolyser (co-rotating discs)) using numerical and semianalytical methods for inert tracer transport. Results are compared to existing data. Mixing in the three cells is modelled using finite element techniques applied to convection-dominated inert tracer transport. For the capillary

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

    ERIC Educational Resources Information Center

    Luo, Yuyan; Kaufman, Lisa; Baillargeon, Renee

    2009-01-01

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

  16. Optimizing Steam & Condensate System: A Case Study 

    E-print Network

    Venkatesan, V. V.; Norris, C.

    2011-01-01

    for electricity). The site generates steam for its process operation from 3 gas fired boilers at 525-psig pressure. The steam is consumed at 5 process areas; Acid, Basics, Crystals, Derivatives & Hydrogen plants. All of the process areas recover condensate inside...

  17. Condensate-removal device for heat exchangers

    NASA Technical Reports Server (NTRS)

    Trusch, R. B.; Oconnor, E. W.

    1973-01-01

    Device comprises array of perforated tubes manifolded together and connected to a vacuum suction device. Vacuum applied to these tubes pulls mixture of condensate and effluent gas through perforations and along length of tubes to discharge device. Discharge device may be a separator which separates water vapor from effluent air and allows recirculation of both of them.

  18. MOBILE BED FLUX FORCE/CONDENSATION SCRUBBERS

    EPA Science Inventory

    The report gives results of an experimental determination of fine particle collection in mobile bed scrubbers. Particle collection efficiency increased greatly as the gas-phase pressure drop increased. With no water vapor condensation, the performance capability of a mobile bed s...

  19. Biotreatment of UCG waste water condensate

    Microsoft Academic Search

    M. J. Humenick; R. Brauer; T. Caire; D. F. Lawler

    1984-01-01

    The process of underground coal gasification (UCG) generates a waste water stream during the cooling and processing of the product gas. The waste water stream is of large enough volume and contains a wide array of pollutants, thus posing a significant water pollution problem. The character of UCG condensate is similar to that produced by above-ground gasifiers, although some differences

  20. Improved Assembly for Gas Shielding During Welding or Brazing

    NASA Technical Reports Server (NTRS)

    Gradl, Paul; Baker, Kevin; Weeks, Jack

    2009-01-01

    An improved assembly for inert-gas shielding of a metallic joint is designed to be useable during any of a variety of both laser-based and traditional welding and brazing processes. The basic purpose of this assembly or of a typical prior related assembly is to channel the flow of a chemically inert gas to a joint to prevent environmental contamination of the joint during the welding or brazing process and, if required, to accelerate cooling upon completion of the process.

  1. Explosion Safety Aspects of Shock Wave-Induced Condensation in Fuel-Rich Gaseous Mixtures

    Microsoft Academic Search

    Pavel A. Fomin; Jenq-Renn Chen

    2008-01-01

    The possibility of fuel vapor condensation in shock waves in fuel-rich cyclohexane-oxygen gaseous mixtures is shown. The influence of fuel vapor condensation on shock waves parameters and explosion behavior of corresponding mixtures is analyzed. It is shown, that condensation process led to the increase of pressure and temperature and can essentially change the chemical composition of the gas. For example,

  2. Bose-Einstein Condensate: A New state of matter KISHORE T. KAPALE

    E-print Network

    Allen, Roland E.

    Bose-Einstein Condensate: A New state of matter KISHORE T. KAPALE June 24, 2003 #12;BOSE-EINSTEIN CONDENSATE: A NEW STATE OF MATTER 1 Outline · Introductory Concepts Bosons and Fermions Classical and Quantum-EINSTEIN CONDENSATE: A NEW STATE OF MATTER 2 Bosons and Fermions · The behavior of a gas of identical particles at low

  3. MOLECULAR SPECTROSCPY AND REACTIONS OF ACTINIDES IN THE GAS PHASE AND CRYOGENIC MATRICES

    SciTech Connect

    Heaven, Michael C.; Gibson, John K.; Marcalo, Joaquim

    2009-02-01

    In this chapter we review the spectroscopic data for actinide molecules and the reaction dynamics for atomic and molecular actinides that have been examined in the gas phase or in inert cryogenic matrices. The motivation for this type of investigation is that physical properties and reactions can be studied in the absence of external perturbations (gas phase) or under minimally perturbing conditions (cryogenic matrices). This information can be compared directly with the results from high-level theoretical models. The interplay between experiment and theory is critically important for advancing our understanding of actinide chemistry. For example, elucidation of the role of the 5f electrons in bonding and reactivity can only be achieved through the application of experimentally verified theoretical models. Theoretical calculations for the actinides are challenging due the large numbers of electrons that must be treated explicitly and the presence of strong relativistic effects. This topic has been reviewed in depth in Chapter 17 of this series. One of the goals of the experimental work described in this chapter has been to provide benchmark data that can be used to evaluate both empirical and ab initio theoretical models. While gas-phase data are the most suitable for comparison with theoretical calculations, there are technical difficulties entailed in generating workable densities of gas-phase actinide molecules that have limited the range of species that have been characterized. Many of the compounds of interest are refractory, and problems associated with the use of high temperature vapors have complicated measurements of spectra, ionization energies, and reactions. One approach that has proved to be especially valuable in overcoming this difficulty has been the use of pulsed laser ablation to generate plumes of vapor from refractory actinide-containing materials. The vapor is entrained in an inert gas, which can be used to cool the actinide species to room temperature or below. For many spectroscopic measurements, low temperatures have been achieved by co-condensing the actinide vapor in rare gas or inert molecule host matrices. Spectra recorded in matrices are usually considered to be minimally perturbed. Trapping the products from gas-phase reactions that occur when trace quantities of reactants are added to the inert host gas has resulted in the discovery of many new actinide species. Selected aspects of the matrix isolation data were discussed in chapter 17. In the present chapter we review the spectroscopic matrix data in terms of its relationship to gas-phase measurements, and update the description of the new reaction products found in matrices to reflect the developments that have occurred during the past two years. Spectra recorded in matrix environments are usually considered to be minimally perturbed, and this expectation is borne out for many closed shell actinide molecules. However, there is growing evidence that significant perturbations can occur for open shell molecules, resulting in geometric distortions and/or electronic state reordering. Studies of actinide reactions in the gas phase provide an opportunity to probe the relationship between electronic structure and reactivity. Much of this work has focused on the reactions of ionic species, as these may be selected and controlled using various forms of mass spectrometry. As an example of the type of insight derived from reaction studies, it has been established that the reaction barriers for An+ ions are determined by the promotion energies required to achieve the 5fn6d7s configuration. Gas-phase reaction studies also provide fundamental thermodynamic properties such as bond dissociation and ionization energies. In recent years, an increased number of gas-phase ion chemistry studies of bare (atomic) and ligated (molecular) actinide ions have appeared, in which relevant contributions to fundamental actinide chemistry have been made. These studies were initiated in the 1970's and carried out in an uninterrupted way over the course of the past three d

  4. Ensuring condensate recovery efficiency.

    PubMed

    Mayoh, Paul

    2012-09-01

    According to steam system specialist, Spirax Sarco, 'condensate contains about a quarter of the energy of the steam from which it came--a significant amount of heat available to an energy centre'. Ensuring that existing condensate recovery systems are as efficient as possible is therefore 'key' to reducing energy centre costs, the company says. Paul Mayoh, product manager, Spirax Sarco, considers ways to ensure that as much condensate as possible is re-used. PMID:23009016

  5. LATTICE GAS SUPERFLUID

    Microsoft Academic Search

    JEFFREY YEPEZ

    A quantum computer, with controlled decoherence, constructed out of a lattice based array of qubits undergoing a particular local and unitary evolution is eectively a bose condensate. Presented is a coupled lattice gas system, a quantum lattice gas and a classical lattice gas in mutual contact through \\\\external\\

  6. Gas-separation process

    DOEpatents

    Toy, Lora G. (San Francisco, CA); Pinnau, Ingo (Palo Alto, CA); Baker, Richard W. (Palo Alto, CA)

    1994-01-01

    A process for separating condensable organic components from gas streams. The process makes use of a membrane made from a polymer material that is glassy and that has an unusually high free volume within the polymer material.

  7. Higgs properties in a broken Inert Doublet Model

    E-print Network

    Rikard Enberg; Johan Rathsman; Glenn Wouda

    2014-12-22

    We consider a model for the Higgs sector with two scalar doublets and a broken $Z_2$ symmetry, the Stealth Doublet Model, where the $Z_2$ symmetry is manifest in the Yukawa sector but broken by the scalar potential. This model can be seen as a generalization of the Inert Doublet Model. One of the doublets is the Higgs doublet that participates in electroweak symmetry breaking and couples to fermions. The other doublet does not couple to fermions at tree level and does not acquire a vacuum expectation value. The broken $Z_2$ symmetry leads to interesting phenomenology such as mixing between the two doublets and charged and CP-odd scalars that can be light and have unusual decay channels. We present theoretical and experimental constraints on the model and consider the recent observation of a Higgs boson at the LHC. The data on the $H\\to\\gamma\\gamma$ channel can be naturally accommodated in the model, with either the lightest or the heaviest CP-even scalar playing the role of the observed particle.

  8. Investigation of materials for inert electrodes in aluminum electrodeposition cells

    SciTech Connect

    Haggerty, J. S.; Sadoway, D. R.

    1987-09-14

    Work was divided into major efforts. The first was the growth and characterization of specimens; the second was Hall cell performance testing. Cathode and anode materials were the subject of investigation. Preparation of specimens included growth of single crystals and synthesis of ultra high purity powders. Special attention was paid to ferrites as they were considered to be the most promising anode materials. Ferrite anode corrosion rates were studied and the electrical conductivities of a set of copper-manganese ferrites were measured. Float Zone, Pendant Drop Cryolite Experiments were undertaken because unsatisfactory choices of candidate materials were being made on the basis of a flawed set of selection criteria applied to an incomplete and sometimes inaccurate data base. This experiment was then constructed to determine whether the apparatus used for float zone crystal growth could be adapted to make a variety of important based melts and their interactions with candidate inert anode materials. The third major topic was Non Consumable Anode (Data Base, Candidate Compositions), driven by our perception that the basis for prior selection of candidate materials was inadequate. Results are presented. 162 refs., 39 figs., 18 tabs.

  9. Asymmetric Inelastic Inert Doublet Dark Matter from Triplet Scalar Leptogenesis

    E-print Network

    Arina, Chiara

    2011-01-01

    The nature of dark matter (DM) particles and the mechanism that provides their measured relic abundance are currently unknown. In this paper we investigate inert scalar and vector like fermion doublet DM candidates with a charge asymmetry in the dark sector, which is generated by the same mechanism that provides the baryon asymmetry, namely baryogenesis-via-leptogenesis induced by decays of scalar triplets. At the same time the model gives rise to neutrino masses in the ballpark of oscillation experiments via type II seesaw. We discuss possible sources of depletion of asymmetry in the DM and visible sectors and solve the relevant Boltzmann equations for quasi-equilibrium decay of triplet scalars. A Monte-Carlo-Markov-Chain analysis is performed for the whole parameter space. The survival of the asymmetry in the dark sector leads to inelastic scattering off nuclei. We then apply bayesian statistic to infer the model parameters favoured by the current experimental data, in particular the DAMA annual modulation ...

  10. Asymmetric Inelastic Inert Doublet Dark Matter from Triplet Scalar Leptogenesis

    E-print Network

    Chiara Arina; Narendra Sahu

    2011-09-01

    The nature of dark matter (DM) particles and the mechanism that provides their measured relic abundance are currently unknown. In this paper we investigate inert scalar and vector like fermion doublet DM candidates with a charge asymmetry in the dark sector, which is generated by the same mechanism that provides the baryon asymmetry, namely baryogenesis-via-leptogenesis induced by decays of scalar triplets. At the same time the model gives rise to neutrino masses in the ballpark of oscillation experiments via type II seesaw. We discuss possible sources of depletion of asymmetry in the DM and visible sectors and solve the relevant Boltzmann equations for quasi-equilibrium decay of triplet scalars. A Monte-Carlo-Markov-Chain analysis is performed for the whole parameter space. The survival of the asymmetry in the dark sector leads to inelastic scattering off nuclei. We then apply bayesian statistic to infer the model parameters favoured by the current experimental data, in particular the DAMA annual modulation and Xenon100 exclusion limit. The latter strongly disfavours asymmetric scalar doublet DM of mass $\\mathcal{O}(\\TeV)$ as required by DM-$\\bar{\\rm DM}$ oscillations, while an asymmetric vector like fermion doublet DM with mass around 100 GeV is a good candidate for DAMA annual modulation yet satisfying the constraints from Xenon100 data.

  11. Inert dark matter in type-II seesaw

    NASA Astrophysics Data System (ADS)

    Chen, Chuan-Hung; Nomura, Takaaki

    2014-09-01

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

  12. Metal ion implantation in inert polymers for strain gauge applications

    NASA Astrophysics Data System (ADS)

    Di Girolamo, Giovanni; Massaro, Marcello; Piscopiello, Emanuela; Tapfer, Leander

    2010-10-01

    Metal ion implantation in inert polymers may produce ultra-thin conducting films below the polymer surface. These subsurface films are promising structures for strain gauge applications. To this purpose, polycarbonate substrates were irradiated at room temperature with low-energy metal ions (Cu + and Ni +) and with fluences in the range between 1 × 10 16 and 1 × 10 17 ions/cm 2, in order to promote the precipitation of dispersed metal nanoparticles or the formation of a continuous thin film. The nanoparticle morphology and the microstructural properties of polymer nanocomposites were investigated by glancing-incidence X-ray diffraction and transmission electron microscopy (TEM) measurements. At lower fluences (<5 × 10 16 ions/cm 2) a spontaneous precipitation of spherical-shaped metal nanoparticles occurred below the polymer top-surface (˜50 nm), whereas at higher fluences the aggregation of metal nanoparticles produced the formation of a continuous polycrystalline nanofilm. Furthermore, a characteristic surface plasmon resonance peak was observed for nanocomposites produced at lower ion fluences, due to the presence of Cu nanoparticles. A reduced electrical resistance of the near-surface metal-polymer nanocomposite was measured. The variation of electrical conductivity as a function of the applied surface load was measured: we found a linear relationship and a very small hysteresis.

  13. Experimental Study of Wettability Alteration to Preferential Gas-Wetting in

    E-print Network

    Firoozabadi, Abbas

    of Critical- Condensate Saturation and Relative Permeabilities in Gas- Condensate Systems,'' paper SPE 56014 from preferential liquid-wetting to preferen- tial gas-wetting, then gas-well deliverability in gas-condensate° and from 0 to 60° by FC754 for water-air and normal decane-air systems, respec- tively. While untreated

  14. CFD Simulation of Oscillating Flow in an Inertance Tube and its Comparison to Other Models

    NASA Astrophysics Data System (ADS)

    Gustafson, S.; Flake, B.; Razani, A.

    2006-04-01

    Three first-order models usually used to simulate the effect of inertance tube as a phase-shifter used in Pulse-Tube Refrigerators (PTRs) are compared to the results of Computational Fluid Dynamics (CFD) simulation using a commercial CFD software package. The results of the CFD calculations are first validated by their comparison to experimental results for a compressor, inertance tube, and a reservoir system. Good agreement between experimental and numerical calculations is obtained. The three first-order models usually used in design analysis of inertance PTRs take into account the inertance, the compliance, and the fluid flow resistance associated with oscillating flow in the inertance tube. The three models consist of the lumped parameter method, the transmission line theory, and the analytical solution to the hyperbolic equation representing oscillating fluid flow in the inertance tube. The comparison of the results of the three models and the CFD simulation for different parameters important in the design of inertance PTRs are presented in this investigation.

  15. z=0 z=0 z=0 Steam-turbin Condenser LP-pump

    E-print Network

    Skogestad, Sigurd

    ¡ ¢£ ¤ ¥§¦ ¨ © ¥£ ¡ £ ¨ © ¦ ¦ ¡ £ ¨ © ¦ ¦ ¥ ¦ © © ¡ ¥ ¥ £ ¦ ¡ ! ¦ " ©# £ $ ¤ #12; 4 ¡ 3 @ ¢ 2 6 3 F 4 9 7 LC LC PC z=0 z=0 z=0 z=1 z=1 TC TC z=0 HP-pump Steam-turbin Condenser LP-pump Air compressor Deaerator HP-pump Steam-turbin Condenser LP-pump Air compressor Deaerator HP-pump Condenser LP-pump Air compressor Deaerator Pre-heaterSuper-heater Evaporator Economizer Condenser drum Gas

  16. Development of improved technologies and techniques for reducing base gas requirements in underground natural gas storage facilities. Mathematical model. Final report, July 1986-September 1987

    SciTech Connect

    Modine, A.D.; Bashbush, J.L.

    1987-12-01

    Base gas requirements in the U.S. amount to a few trillion cubic feet. The Gas Research Institute has proposed a gas-storage operating plan whereby an inert gas or a low-BTU gas could be injected to replace part of the hydrocarbon gas. A reservoir simulator was developed to solve gas-water reservoir problems where the gas may be treated as a two-component miscible mixture. The simulator is based on a modification of SSI's standard 3-phase, 3-dimensional reservoir simulator and, therefore, it encompasses the experience of more than 20 years of simulation technology. To accomplish the task, the oil equation was removed and a means of tracking a second component (inert) in the gas phase was added. The movement of the inert component was described with the method of characteristics to practically eliminate the numerical dispersion problems associated with the solution of the flow equations with standard finite-difference methods.

  17. Dilepton constraints in the inert doublet model from Run 1 of the LHC

    NASA Astrophysics Data System (ADS)

    Bélanger, Geneviève; Dumont, Béranger; Goudelis, Andreas; Herrmann, Björn; Kraml, Sabine; Sengupta, Dipan

    2015-06-01

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

  18. Inert anode containing base metal and noble metal useful for the electrolytic production of aluminum

    DOEpatents

    Ray, Siba P. (Murrysville, PA); Liu, Xinghua (Monroeville, PA)

    2000-01-01

    An inert anode for production of metals such as aluminum is disclosed. The inert anode comprises a base metal selected from Cu and Ag, and at least one noble metal selected from Ag, Pd, Pt, Au, Rh, Ru, Ir and Os. The inert anode may optionally be formed of sintered particles having interior portions containing more base metal than noble metal and exterior portions containing more noble metal than base metal. In a preferred embodiment, the base metal comprises Cu, and the noble metal comprises Ag, Pd or a combination thereof.

  19. Soft Condensed Matter Biopolymers

    E-print Network

    Schüler, Axel

    Keywords Soft Condensed Matter Biopolymers Cell Elasticity Neuronal Networks Biomimetic properties of membranes and bi- opolymers. Current interests are fo- cused on the plasma membrane condensed matter. In the living cell, this matter is often far from equilib- rium and also behaving in a non

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

    SciTech Connect

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

    1993-10-01

    This thesis discusses the following on resonant holographic measurements of laser ablation plume expansion: Introduction to laser ablation; applications of laser ablation; The study of plume expansion; holographic interferometry; resonant holographic interferometry; accounting for finite laser bandwidth; The solution for doppler broadening and finite bandwidth; the main optical table; the lumonics laser spot shape; developing and reconstructing the holograms; plume expansion in RF/Plasma Environments; Determining {lambda}{sub o}; resonant refraction effects; fringe shift interpretation; shot-to-shot consistency; laser ablation in vacuum and low pressure, inert, background gas; theoretically modeling plume expansion in vacuum and low pressure, inert, background gas; and laser ablation in higher pressure, inert, background gas.

  1. Wafer chamber having a gas curtain for extreme-UV lithography

    DOEpatents

    Kanouff, Michael P. (Livermore, CA); Ray-Chaudhuri, Avijit K. (Livermore, CA)

    2001-01-01

    An EUVL device includes a wafer chamber that is separated from the upstream optics by a barrier having an aperture that is permeable to the inert gas. Maintaining an inert gas curtain in the proximity of a wafer positioned in a chamber of an extreme ultraviolet lithography device can effectively prevent contaminants from reaching the optics in an extreme ultraviolet photolithography device even though solid window filters are not employed between the source of reflected radiation, e.g., the camera, and the wafer. The inert gas removes the contaminants by entrainment.

  2. The effect of air on condensation of stratified horizontal concurrent steam/water flow

    SciTech Connect

    Chan, T.S.; Yuen, M.C. (Northwestern Univ., Evanston, IL (USA))

    1990-11-01

    The present note reports a continuation of a systematic experimental study on the direct-contact condensation of concurrent steam/water flow. Data for pure steam condensation have been published by Lim et al. (1984). New data including the noncondensible gas effect are given here. Previous correlations are also extended to include the noncondensible gas effect.

  3. Bose-Einstein condensation of metastable helium.

    PubMed

    Pereira Dos Santos, F; Léonard, J; Wang, J; Barrelet, C J; Perales, F; Rasel, E; Unnikrishnan, C S; Leduc, M; Cohen-Tannoudji, C

    2001-04-16

    We have observed a Bose-Einstein condensate in a dilute gas of 4He in the (3)2S(1) metastable state. We find a critical temperature of (4.7+/-0.5) microK and a typical number of atoms at the threshold of 8 x 10(6). The maximum number of atoms in our condensate is about 5 x 10(5). An approximate value for the scattering length a = (16+/-8) nm is measured. The mean elastic collision rate at threshold is then estimated to be about 2 x 10(4) s(-1), indicating that we are deeply in the hydrodynamic regime. The typical decay time of the condensate is 2 s, which places an upper bound on the rate constants for two-body and three-body inelastic collisions. PMID:11327998

  4. Thermocapillary flow with evaporation and condensation and its effect on liquid retention in low-G fluid acquisition devices

    NASA Astrophysics Data System (ADS)

    Schmidt, George R.

    1994-02-01

    The steady motion, thermal and free surface behavior of a volatile, wetting liquid in microgravity are studied using scaling and numerical techniques. The objective is to determine whether the thermocapillary and two-phase convection arising from thermodynamic nonequilibrium along the porous surfaces of spacecraft liquid acquisition devices could cause the retention failures observed with liquid hydrogen and heated vapor pressurant. Why these devices seem immune to retention loss when pressurized with heated helium or heated directly through the porous structure was also examined. Results show that highly wetting fluids exhibit large negative and positive dynamic pressure gradients towards the meniscus interline when superheated and subcooled, respectively. With superheating, the pressure variation and recoil force arising from liquid/vapor phase change exert the same influence on surface morphology and promote retention. With subcooling, however, the pressure distribution produces a suction that degrades mechanical equilibrium of the surface. This result indicates that thermocapillary-induced deformation arising from subcooling and condensation is the likely cause for retention loss. In addition, increasing the level of nonequilibrium by reducing accommodation coefficient suppresses deformation and explains why this failure mode does not occur in instances of direct screen heating or pressurization with a heated inert gas.

  5. Development of dual phase magnesia-zirconia ceramics for light water reactor inert matrix fuel

    E-print Network

    Medvedev, Pavel

    2005-02-17

    Dual phase magnesia-zirconia ceramics were developed, characterized, and evaluated as a potential matrix material for use in light water reactor inert matrix fuel intended for the disposition of plutonium and minor actinides. Ceramics were...

  6. For cermet inert anode containing oxide and metal phases useful for the electrolytic production of metals

    DOEpatents

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

    2002-01-01

    A cermet inert anode for the electrolytic production of metals such as aluminum is disclosed. The inert anode comprises a ceramic phase including an oxide of Ni, Fe and M, where M is at least one metal selected from Zn, Co, Al, Li, Cu, Ti, V, Cr, Zr, Nb, Ta, W, Mo, Hf and rare earths, preferably Zn and/or Co. Preferred ceramic compositions comprise Fe.sub.2 O.sub.3, NiO and ZnO or CoO. The cermet inert anode also comprises a metal phase such as Cu, Ag, Pd, Pt, Au, Rh, Ru, Ir and/or Os. A preferred metal phase comprises Cu and Ag. The cermet inert anodes may be used in electrolytic reduction cells for the production of commercial purity aluminum as well as other metals.

  7. Lepton Flavor Violation in the Inert Scalar Model with Higher Representations

    E-print Network

    Chowdhury, Talal Ahmed

    2015-01-01

    We investigate the lepton flavor violation (LFV) in the inert scalar model with higher representations. We generalize the inert doublet model with right handed neutrino by using higher scalar and fermion representation of $SU(2)_{L}$. As the generalized model and the inert doublet model have the same parameter space, we compare the rates of $\\mu\\rightarrow e\\gamma$, $\\mu\\rightarrow ee\\overline{e}$ and $\\mu-e$ conversion in nuclei in the doublet and its immediate extension, the quartet model. We show that the corresponding rates are larger in the case of higher representation compared to the Inert doublet for the same region of parameter space. This implies that such extended models are more constrained by current LFV bounds and will have better prospects in future experiments.

  8. Inert anode containing oxides of nickel iron and cobalt useful for the electrolytic production of metals

    DOEpatents

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

    2002-01-01

    An inert anode for the electrolytic production of metals such as aluminum is disclosed. The inert anode includes a ceramic oxide material preferably made from NiO, Fe.sub.2 O.sub.3 and CoO. The inert anode composition may comprise the following mole fractions of NiO, Fe.sub.2 O.sub.3 and CoO: 0.15 to 0.99 NiO; 0.0001 to 0.85 Fe.sub.2 O.sub.3 ; and 0.0001 to 0.45 CoO. The inert anode may optionally include other oxides and/or at least one metal phase, such as Cu, Ag, Pd, Pt, Au, Rh, Ru, Ir and/or Os. The Ni--Fe--Co--O ceramic material exhibits very low solubility in Hall cell baths used to produce aluminum.

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

    SciTech Connect

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

    2013-03-15

    The problem of searching for the potential energy and the energy spectrum of the electrons localized over the surface of a thin liquid or solid inert film due to address electrodes placed under the film is considered.

  10. Inert anode containing oxides of nickel, iron and zinc useful for the electrolytic production of metals

    DOEpatents

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

    2002-01-01

    An inert anode for the electrolytic production of metals such as aluminum is disclosed. The inert anode includes a ceramic oxide material preferably made from NiO, Fe.sub.2 O.sub.3 and ZnO. The inert anode composition may comprise the following mole fractions of NiO, Fe.sub.2 O.sub.3 and ZnO: 0.2 to 0.99 NiO; 0.0001 to 0.8 Fe.sub.2 O.sub.3 ; and 0.0001 to 0.3 ZnO. The inert anode may optionally include other oxides and/or at least one metal phase, such as Cu, Ag, Pd, Pt, Au, Rh, Ru, Ir and/or Os. The Ni--Fe--Co--O ceramic material exhibits very low solubility in Hall cell baths used to produce aluminum.

  11. 30 CFR 75.1107-12 - Inerting of mine atmosphere prohibited.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Fire Protection Fire Suppression Devices and Fire-Resistant Hydraulic Fluids on Underground Equipment § 75.1107-12 Inerting of mine atmosphere prohibited. No fire suppression...

  12. In-stack condensible particulate matter measurements and issues.

    PubMed

    Corio, L A; Sherwell, J

    2000-02-01

    Particulate matter (PM) emitted from fossil fuel-fired units can be classified as either filterable or condensible PM. Condensible PM typically is not measured because federal and most state regulations do not require sources to do so. To determine the magnitude of condensible PM emissions relative to filterable PM emissions and to better understand condensible PM measurement issues, a review and analysis of actual U.S. Environmental Protection Agency (EPA) Method 202 (for in-stack condensible PM10) and EPA Method 201/201A (for in-stack filterable PM10) results were conducted. Methods 202 and 201/201A results for several coal-burning boilers showed that the condensible PM, on average, comprises approximately three-fourths (76%) of the total PM10 stack emissions. Methods 202 and 201/201A results for oil- and natural gas-fired boilers showed that the condensible PM, on average, comprises 50% of the total PM10 stack emissions. Methods 202 and 201/201A results for oil-, natural gas-, and kerosene-fired combustion turbines showed that the condensible PM, on average, comprises 69% of the total PM10 stack emissions. Based on these limited measurements, condensible PM can make a significant contribution to total PM10 emissions for fossil fuel-fired units. A positive bias (indicating more condensible PM than is actually emitted) may exist in the measured data due to the conversion of dissolved sulfur dioxide to sulfate compounds in the sampling procedure. In addition, these Method 202 results confirm that condensible PM, on average, is composed mostly of inorganic matter, regardless of the type of fuel burned. PMID:10680350

  13. Mathematical modeling of detonation suppression in a hydrogen-oxygen mixture by inert particles

    Microsoft Academic Search

    A. V. Fedorov; D. A. Tropin; I. A. Bedarev

    2010-01-01

    The paper addresses the problem of searching for methods that can control, suppress, and attenuate explosive and detonation\\u000a processes in homogeneous and heterogeneous media (mixtures of reactive gases and inert species). The analysis is performed\\u000a by analytical and numerical methods. The problem of detonation suppression in a mixture of reactive gases and inert species\\u000a (argon and sand particles) in a

  14. Fourier transform infrared study of amorphous N2O4 solid: Destabilization with inert impurities

    NASA Astrophysics Data System (ADS)

    Givan, A.; Loewenschuss, A.

    1991-06-01

    Amorphous N2O4 solid was formed on predeposited oxygen or krypton layers. Evaporation of the underlying layer and redeposition of the inert impurities resulted in decomposition of the ionic nitrosonium nitrate clusters within the solid nitrogen tetroxide. Infrared features indicate NO+NO-3 decomposition to occur via molecular NONO3, with NO2 monomers as products. Evaporation of the inert impurities and recooling restored the amorphous N2O4 from which NO+NO-3 was formed again.

  15. Experimental investigation and numerical validation of explosion suppression by inert particles in large-scale duct

    Microsoft Academic Search

    Gang Dong; Baochun Fan; Bo Xie; Jingfang Ye

    2005-01-01

    A large-scale duct with an explosion suppressor was designed to investigate experimentally the explosion suppression by inert particles for a CH4\\/O2\\/N2 mixture. The duct is 25m long and has an internal diameter of 700mm. Pressure and flame signals were recorded some distance away from ignitor in the duct. Pressure tracking lines of the shock front for the different inert particle

  16. Fabrication of particle dispersed inert matrix fuel based on liquid phase sintered SiC

    Microsoft Academic Search

    D. Pavlyuchkov; R. H. Baney; J. S. Tulenko; H. J. Seifert

    2011-01-01

    In the present work, liquid phase sintered SiC (LPS-SiC) was proposed as an inert matrix for the particle dispersed inert matrix fuel (IMF). The fuel particles containing plutonium and minor actinides were substituted with pure yttria stabilized zirconia beads. The LPS-SiC matrix was produced from the initial mixtures prepared using submicron sized alpha-SiC powder and oxide additives Al2O3, Y2O3 in

  17. Fabrication of particle dispersed inert matrix fuel based on liquid phase sintered SiC

    Microsoft Academic Search

    D. Pavlyuchkov; R. H. Baney; J. S. Tulenko; H. J. Seifert

    2011-01-01

    In the present work, liquid phase sintered SiC (LPS-SiC) was proposed as an inert matrix for the particle dispersed inert matrix fuel (IMF). The fuel particles containing plutonium and minor actinides were substituted with pure yttria stabilized zirconia beads. The LPS-SiC matrix was produced from the initial mixtures prepared using submicron sized ?-SiC powder and oxide additives Al2O3, Y2O3 in

  18. Analysis of the influence of inert particles on the propagation of a cellular heterogeneous detonation

    NASA Astrophysics Data System (ADS)

    Fedorov, A. V.; Kratova, Y. V.

    2015-05-01

    The interaction of a cellular detonation wave with a cloud of inert particles is investigated numerically. The regimes of propagation of the heterogeneous cellular detonation and its suppression are identified. The influence of various parameters of the inert cloud is demonstrated. The critical length of the cloud for detonation suppression is determined. It is shown that the disperse composition and the non-uniform distribution of particles of the particle cloud are important parameters affecting the detonation propagation mode.

  19. Kinetics of mineral condensation in the solar nebula

    NASA Technical Reports Server (NTRS)

    Grove, T. L.

    1987-01-01

    A natural extension of the type of gas-mineral-melt condensation experiments is to study the gas-mineral-melt reaction process by controlling the reaction times of appropriate gas compositions with silicate materials. In a condensing and vaporizing gas-solid system, important processes that could influence the composition of and speciation in the gas phase are the kinetics of vaporization of components from silicate crystals and melts. The high vacuum attainable in the space station would provide an environment for studying these processes at gas pressures much lower than those obtainable in experimental devices operated at terrestrial conditions in which the gas phase and mineral or melt would be allowed to come to exchange equilibrium. Further experiments would be performed at variable gas flow rates to simulate disequilibrium vapor fractionation. In this type of experiment it is desirable to analyze directly the species in the gas phase in equilibrium with the condensed silicate material. This analytical method would provide a direct determination of the species present in the gas phase. Currently, the notion of gas speciation is based on calculations from thermodynamic data. The proposed experiments require similar furnace designs and use similar experimental starting compositions, pressures, and temperatures as those described by Mysen.

  20. Peptide derived from Pvfp-1 as bioadhesive on bio-inert surface.

    PubMed

    Jiang, Zhen; Yu, Yabiao; Du, Lina; Ding, Xiyu; Xu, Hui; Sun, Yanan; Zhang, Qiqing

    2012-02-01

    Surface property is one important characteristic of materials, especially for ones that are bio-inert but designed for bio-medical application. In this study, we designed a series of peptides and compared their capacities as bioadhesive to improve the surface bioactivity of bio-inert material. The peptides were designed according to the sequence of Perna viridis foot protein 1 (Pvfp-1), one of the Mfp-1s (mussel foot protein 1) which play key roles in wet adhesion of mussel byssus. And the Teflon (PTFE) was chosen as a model of bio-inert material. With adsorption, adhesion and coating analysis, it was found that peptide C2 (M) (derived from the non-repeating region of Pvfp-1, contains modified DOPA) has superior coating and adhesion abilities especially on the bio-inert surface of PTFE. After coating with peptide C2 (M), the cell adhesion and spreading of osteoblast MC3T3-E1 cells on PTFE were significantly improved compared with those on non-coated surface, and the peptide-coating did not show any cell toxicity. Therefore, peptide C2 (M) is effective for improving the bioactivity of bio-inert PTFE, and could be potentially used as a bioadhesive on other bio-inert materials for biomedical application. Moreover, this study also provided new insights in designing other peptide-based bioadhesive materials. PMID:22079698

  1. Biotreatment of UCG waste water condensate

    SciTech Connect

    Humenick, M.J.; Brauer, R.; Caire, T.; Lawler, D.F.

    1984-01-01

    The process of underground coal gasification (UCG) generates a waste water stream during the cooling and processing of the product gas. The waste water stream is of large enough volume and contains a wide array of pollutants, thus posing a significant water pollution problem. The character of UCG condensate is similar to that produced by above-ground gasifiers, although some differences are apparent. The treatment options studied during this laboratory experimental project were activated sludge treatment of raw condensate, activated sludge treatment of stripped condensate, and activated sludge with powdered activated carbon addition for treatment of stripped condensate. The condensates used in the laboratory study were obtained from large-scale field tests in Wyoming. Design and kinetic information for the various activated sludge options are presented, along with detailed performance and kinetic data. Major variables among the treatment options were the amount of dilution water needed to achieve stable operation, the degree of treatment achieved by each option, and the stability of the biological reactor.

  2. Laser Isotope Separation Employing Condensation Repression

    SciTech Connect

    Eerkens, Jeff W.; Miller, William H.

    2004-09-15

    Molecular laser isotope separation (MLIS) techniques using condensation repression (CR) harvesting are reviewed and compared with atomic vapor laser isotope separation (AVLIS), gaseous diffusion (DIF), ultracentrifuges (UCF), and electromagnetic separations (EMS). Two different CR-MLIS or CRISLA (Condensation Repression Isotope Separation by Laser Activation) approaches have been under investigation at the University of Missouri (MU), one involving supersonic super-cooled free jets and dimer formation, and the other subsonic cold-wall condensation. Both employ mixtures of an isotopomer (e.g. {sup i}QF{sub 6}) and a carrier gas, operated at low temperatures and pressures. Present theories of VT relaxation, dimerization, and condensation are found to be unsatisfactory to explain/predict experimental CRISLA results. They were replaced by fundamentally new models that allow ab-initio calculation of isotope enrichments and predictions of condensation parameters for laser-excited and non-excited vapors which are in good agreement with experiment. Because of supersonic speeds, throughputs for free-jet CRISLA are a thousand times higher than cold-wall CRISLA schemes, and thus preferred for large-quantity Uranium enrichments. For small-quantity separations of (radioactive) medical isotopes, the simpler coldwall CRISLA method may be adequate.

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

    PubMed

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

    2014-12-16

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

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

    E-print Network

    Eseltine, Dustin E.

    2012-02-14

    to N? and Ar (which are entirely inert), making it better suited for use as a fuel for co-firing with coal or gasification. Three different biomasses were investigated: Juniper wood chips, Mesquite wood chips, and forage Sorghum. Experiments were...

  5. Mechanism of dropwise condensation

    E-print Network

    Umur, Aydin

    1963-01-01

    From a study of surface phenomena, information is obtained about conditions under which net condensation can occur. An experimental examination of the surface, using an optical method capable of detecting thin films of ...

  6. US crude oil, natural gas, and natural gas liquids reserves

    SciTech Connect

    Not Available

    1990-10-05

    This report presents estimates of proved reserves of crude oil, natural gas, and natural gas liquids as of December 31, 1989, and production volumes for the year 1989 for the total United States and for selected states and state sub-divisions. Estimates are presented for the following four categories of natural gas: total gas (wet after lease separation), its two major components (nonassociated and associated-dissolved gas), and total dry gas (wet gas adjusted for the removal of liquids at natural gas processing plants). In addition, two components of natural gas liquids, lease condensate and natural gas plant liquids, have their reserves and production reported separately. Also included is information on indicated additional crude oil reserves and crude oil, natural gas, and lease condensate reserves in nonproducing reservoirs. 28 refs., 9 figs., 15 tabs.

  7. Gas condensate damage in hydraulically fractured wells

    E-print Network

    Adeyeye, Adedeji Ayoola

    2004-09-30

    work has a totally different approach. The effects of reservoir depletion are minimized by introduction of an injector well with fluid composition the same as the original reservoir fluid. It also assumes an infinite conductivity hydraulic fracture...

  8. Condensate System Troubleshooting and Optimization 

    E-print Network

    Jenkins, B. V.

    1983-01-01

    , some of the carbon dioxide dissolves in the conden sate. This forms carbonic acid. Carbonic acid, being a weak acid, will cause four characteristic problems: The pH of the condensate will drop Dissolved iron content of the condensate... will increase Total dissolved solids content of the condensate will also increase A trough-like thinning of the bottom of the condensate pipe occurs. (Fig. 1) Figure 1 - Carbonic Acid Attack on Condensate Piping What is the impact? Iron is dissolved...

  9. Bose-Einstein Condensation in the Luttinger-Sy Model

    Microsoft Academic Search

    Olivier Lenoble; Valentin A. ZAGREBNOV

    2006-01-01

    We present a rigorous study of the Bose-Einstein condensation in the Luttinger-Sy model. We prove the existence of the condensation in this one-dimensional model of the perfect boson gas placed in the Poisson random potential of singular point impurities. To tackle the off-diagonal long-range order we calculate explicitly the corresponding space-averaged one-body reduced density matrix. We show that mathematical mechanism

  10. Bogoliubov sound speed in periodically modulated Bose-Einstein condensates

    E-print Network

    E. Taylor; E. Zaremba

    2003-08-11

    We study the Bogoliubov excitations of a Bose-condensed gas in an optical lattice. Of primary interest is the long wavelength phonon dispersion for both current-free and current-carrying condensates. We obtain the dispersion relation by carrying out a systematic expansion of the Bogoliubov equations in powers of the phonon wave vector. Our result for the current-carrying case agrees with the one recently obtained by means of a hydrodynamic theory.

  11. Many-particle quantum graphs and Bose-Einstein condensation

    NASA Astrophysics Data System (ADS)

    Bolte, Jens; Kerner, Joachim

    2014-06-01

    In this paper, we propose quantum graphs as one-dimensional models with a complex topology to study Bose-Einstein condensation and phase transitions in a rigorous way. We first investigate non-interacting many-particle systems on quantum graphs and provide a complete classification of systems that exhibit Bose-Einstein condensation. We then consider models of interacting particles that can be regarded as a generalisation of the well-known Tonks-Girardeau gas. Here, our principal result is that no phase transitions occur in bosonic systems with repulsive hardcore interactions, indicating an absence of Bose-Einstein condensation.

  12. Condensate fraction of cold gases in a nonuniform external potential

    SciTech Connect

    Astrakharchik, G. E. [Departament de Fisica i Enginyeria Nuclear, Campus Nord B4-B5, Universitat Politecnica de Catalunya, E-08034 Barcelona (Spain); Krutitsky, K. V. [Fakultaet fuer Physik der Universitaet Duisburg-Essen, Campus Duisburg, Lotharstrasse 1, D-47048 Duisburg (Germany)

    2011-09-15

    Exact calculation of the condensate fraction in multidimensional inhomogeneous interacting Bose systems in a confining potential of arbitrary shape is a difficult computational problem. We have developed an iterative procedure which allows us to calculate the condensate fraction as well as the corresponding eigenfunction of the one-body density matrix. We successfully validate this procedure in diffusion Monte Carlo simulations of a Bose gas in an optical lattice at zero temperature. We also discuss the relation between different criteria used for testing coherence in cold Bose systems, such as the fraction of particles that are superfluid, condensed, or in the zero-momentum state.

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

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

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

    E-print Network

    Zhao, Fuman

    2012-02-14

    )????????????????????????..??...70 xii FIGURE Page 5.5 N-butane flammability properties with dilution of nitrogen (25 ?C and 1... and the regressed linear curve...........................................................................................................83 5.15 Experimental n-butane LFL diluted with N2 and the regressed linear curve..????????....????????????????...84 5...

  15. Thorium exposure during tungsten inert gas welding with thoriated tungsten electrodes.

    PubMed

    Gäfvert, T; Pagels, J; Holm, E

    2003-01-01

    The exposure to 232Th from TIG welding with thoriated electrodes has been determined at five different workshops. Welding with both alternating and direct current was investigated. The exposure levels of 232Th were generally below 10 mBq m(-3) in the breathing zone of the welders. Two samples from AC welding showed significant higher exposure levels, probably due to maladjustment of the TIG welding power source. Samples of the respirable fraction of 232Th from grinding thoriated electrodes were also collected showing exposure levels of 5 mBq m(-3) or lower. A dose estimate has been made for two scenarios, one realistic and one with conservative assumptions, showing that the annual committed effective dose from inhalation of 232Th, 230Th, 228Th and 228Ra, for a full-time TIG welder, in the realistic case is below 0.3 mSv and with conservative assumptions around 1 mSv or lower. The contribution from grinding electrodes was lower, 10 microSv or lower in the realistic case and 63 microSv or lower based on conservative assumptions. The study does not exclude occurrence of higher exposure levels under welding conditions different from those prevailing in this study. PMID:12797558

  16. The Tungsten Inert GAS (TIG) Process of Welding Aluminium in Microgravity: Technical and Economic Considerations

    NASA Astrophysics Data System (ADS)

    Ferretti, S.; Amadori, K.; Boccalatte, A.; Alessandrini, M.; Freddi, A.; Persiani, F.; Poli, G.

    2002-01-01

    The UNIBO team composed of students and professors of the University of Bologna along with technicians and engineers from Alenia Space Division and Siad Italargon Division, took part in the 3rd Student Parabolic Flight Campaign of the European Space Agency in 2000. It won the student competition and went on to take part in the Professional Parabolic Flight Campaign of May 2001. The experiment focused on "dendritic growth in aluminium alloy weldings", and investigated topics related to the welding process of aluminium in microgravity. The purpose of the research is to optimise the process and to define the areas of interest that could be improved by new conceptual designs. The team performed accurate tests in microgravity to determine which phenomena have the greatest impact on the quality of the weldings with respect to penetration, surface roughness and the microstructures that are formed during the solidification. Various parameters were considered in the economic-technical optimisation, such as the type of electrode and its tip angle. Ground and space tests have determined the optimum chemical composition of the electrodes to offer longest life while maintaining the shape of the point. Additionally, the power consumption has been optimised; this offers opportunities for promoting the product to the customer as well as being environmentally friendly. Tests performed on the Al-Li alloys showed a significant influence of some physical phenomena such as the Marangoni effect and thermal diffusion; predictions have been made on the basis of observations of the thermal flux seen in the stereophotos. Space transportation today is a key element in the construction of space stations and future planetary bases, because the volumes available for launch to space are directly related to the payload capacity of rockets or the Space Shuttle. The research performed gives engineers the opportunity to consider completely new concepts for designing structures for space applications. In fact, once the optimised parameters are defined for welding in space, it could be possible to weld different parts directly in orbit to obtain much larger sizes and volumes, for example for space tourism habitation modules. The second relevant aspect is technology transfer obtained by the optimisation of the TIG process on aluminium which is often used in the automotive industry as well as in mass production markets.

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

    E-print Network

    Wadley, Haydn

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

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

    PubMed

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

    2014-09-28

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

  20. Design and operation of an inert gas facility for thermoelectric generator storage

    SciTech Connect

    Goebel, C.J.

    1990-01-01

    While the flight hardware is protected by design from the harsh environments of space, its in-air storage often requires special protection from contaminants such as dust, moisture and other gases. One of these components, the radioisotope thermoelectric generator (RTG) which powers the missions, was deemed particularly vulnerable to pre-launch aging because the generators remain operational at core temperatures in excess of 1000 degrees centigrade throughout the storage period. Any oxygen permitted to enter the devices will react with thermally hot components, preferentially with molybdenum in the insulating foils, and with graphites to form CO/CO{sub 2} gases which are corrosive to the thermopile. It was important therefore to minimize the amount of oxygen which could enter, by either limiting the effective in-leakage areas on the generators themselves, or by reducing the relative amount of oxygen within the environment around the generators, or both. With the generators already assembled and procedures in place to assure minimal in-leakage in handling, the approach of choice was to provide a storage environment which contains significantly less oxygen than normal air. 2 refs.

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

    E-print Network

    Zhao, Fuman

    2012-02-14

    .3 Numerical data analysis?????...????..??????.... 81 5.3.1 Hydrocarbon mixture LFL?????...???????..81 5.3.2 Hydrocarbon mixture UFL?????...???????..95 5.4 Fuel mixture MIC ???????????...?..?????..111 ix CHAPTER... Page 5.7 MICs of ethylene and propylene mixtures from experimental measurement and calculation using Eq. (5-10)???????????...113 6.1 Pure fuel (CaHb) combustion productions at LFL with additional nitrogen???????????????????????????119 6...

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

    E-print Network

    Zhou, Wei

    of porosity in the welds. The welding was conducted using alternating current at a voltage of 20­22 V,2 Magnesium alloy AZ91D is widely used because of its relatively higher corrosion resistance and mechanical,4 corrosion resistance5­8 and mechanical properties9 of AZ91D magnesium alloys. Effort has also been made

  3. Computation of Pressure Effects of Inert-Gas Mixtures on Atomic Line Shapes

    Microsoft Academic Search

    Harry C. Jacobson

    1972-01-01

    Recent line-shape experiments on the absorption series of cesium pressurized by various concentration ratios of argon and helium provide an opportunity to study the additivity of perturber interactions. Calculations which assume additivity and which assume additive adiabatic collisions agree well with the reported data. The results suggest that a systematic study of such experiments using accurate digitized data can furnish

  4. Decrements in cognitive performance in metal inert gas welders exposed to aluminium

    PubMed Central

    Akila, R.; Stollery, B. T.; Riihimaki, V.

    1999-01-01

    OBJECTIVES: Often little has been discovered of the cognitive functions affected by occupational toxins because many functions cooperate to produce the single performance scores typically reported from neuropsychological tests. To facilitate the interpretation of neuropsychological scores, the issue of occupational exposure to aluminium was examined with an approach intended to increase understanding of those cognitive processes that may be affected. METHODS: The investigation was a cross sectional study of asymptomatic aluminium welders and a reference group of mild steel welders. Based on urinary aluminium concentrations, welders were classified into a reference (n = 28), low (n = 27), and high (n = 24) exposure group. The mean urinary aluminium concentrations were 0.46, 2.25, and 9.98 mumol/l, respectively. A comprehensive neuropsychological examination was undertaken to assess psychomotor function, simple visual reaction time, attention related tasks, verbal and visual or visuospatial abilities as well as verbal and visual learning and memory. RESULTS: Aluminium welders showed no impairment on the finger tapping, Santa Ana dexterity, simple visual reaction times, any of the verbal memory tasks, the similarities subtest of Wechsler adult intelligence scale, or the Stroop task. However, the low exposed group performed poorer on the memory for designs and on more difficult block design items demanding preliminary visuospatial analysis. The time limited synonym task, embedded figures, digit symbol speed, and the backward counting component of the divided attention task showed exposure-response relations. CONCLUSIONS: The impairments found were circumscribed. When the neuropsychological tasks were scored to show some of the underlying theoretical cognitive structures, the results indicated that performance difficulties were mainly detected in tasks requiring working memory, particularly that relating to processing of visuospatial information. There was also evidence that such impairments are more readily found in time limited tasks involving visually presented material, in which effective visual scanning combined with control of working memory is demanded.   PMID:10615297

  5. Gas-Purged Headspace Liquid Phase Microextraction System for Determination of Volatile and Semivolatile Analytes

    PubMed Central

    Zhang, Meihua; Bi, Jinhu; Yang, Cui; Li, Donghao; Piao, Xiangfan

    2012-01-01

    In order to achieve rapid, automatic, and efficient extraction for trace chemicals from samples, a system of gas-purged headspace liquid phase microextraction (GP-HS-LPME) has been researched and developed based on the original HS-LPME technique. In this system, semiconductor condenser and heater, whose refrigerating and heating temperatures were controlled by microcontroller, were designed to cool the extraction solvent and to heat the sample, respectively. Besides, inert gas, whose gas flow rate was adjusted by mass flow controller, was continuously introduced into and discharged from the system. Under optimized parameters, extraction experiments were performed, respectively, using GP-HS-LPME system and original HS-LPME technique for enriching volatile and semivolatile target compounds from the same kind of sample of 15 PAHs standard mixture. GC-MS analysis results for the two experiments indicated that a higher enrichment factor was obtained from GP-HS-LPME. The enrichment results demonstrate that GP-HS-LPME system is potential in determination of volatile and semivolatile analytes from various kinds of samples. PMID:22448341

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

    PubMed

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

    2014-08-30

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

  7. Inert ambient annealing effect on MANOS capacitor memory characteristics.

    PubMed

    Nikolaou, Nikolaos; Dimitrakis, Panagiotis; Normand, Pascal; Skarlatos, Dimitrios; Giannakopoulos, Konstantinos; Mergia, Konstantina; Ioannou-Sougleridis, Vassilios; Kukli, Kaupo; Niinistö, Jaakko; Mizohata, Kenichiro; Ritala, Mikko; Leskelä, Markku

    2015-03-27

    In this work we report on the influence of nitrogen ambient thermal effects on the performance of Pt/Al2O3/Si3N4/SiO2/Si memory capacitors. Two post deposition annealing (PDA) furnace steps were employed, at 850 and 1050 °C both for 15 min. The alumina films were deposited by atomic layer deposition using TMA/H2O at 250 °C. The structural characteristics of the stacks were evaluated by transmission electron microscopy and x-ray reflectivity measurements. The memory performance of the stacks was evaluated by write/erase and erase/write measurements, endurance and retention testing. It was found that in as-deposited state the Al2O3 layer is defective resulting in strong leakage currents, controlled by deep defects states. Thus, this behavior inhibits the memory functionality of the stacks. PDA crystallizes and condenses the Al2O3 transforming the layer from amorphous to polycrystalline. During this transformation the Al2O3 electrical quality improves greatly indicating that a significant number of these deep defects have been removed during annealing. Physical reasoning implies that the most plausible origin of these deep defects is hydrogen. However, the polycrystalline Al2O3 films showed inferior retention characteristics which are attributed to grain boundary related shallow defects. The findings of this work could pave the way for more efficient annealing schemes, in which an important factor is the time interval for hydrogen out-diffusion from the Al2O3 layer. PMID:25764569

  8. Establishment of an oil and gas database for increased recovery and characterization of oil and gas carbonate reservoir heterogeneity. [Jurassic Smackover Formation

    SciTech Connect

    Kopaska-Merkel, D.C.; Moore, H.E. Jr.; Mann, S.D.; Hall, D.R.

    1992-06-01

    This volume contains maps, well logging correlated to porosity and permeability, structural cross section, graph of production history, porosity vs. natural log permeability plot, detailed core log, paragenetic sequence and reservoir characterization sheet of the following fields in southwest Alabama: Appleton oil field; Barnett oil field; Barrytown oil field; Big Escambia Creek gas and condensate field; Blacksher oil field; Broken Leg Creed oil field; Bucatunna Creed oil field; Chappell Hill oil field; Chatom gas and condensate field; Choctaw Ridge oil field; Chunchula gas and condensate field; Cold Creek oil field; Copeland gas and condensate field; Crosbys Creed gas and condensate field; and East Barnett oil field. (AT)

  9. Establishment of an oil and gas database for increased recovery and characterization of oil and gas carbonate reservoir heterogeneity. Appendix 1, Volume 1

    SciTech Connect

    Kopaska-Merkel, D.C.; Moore, H.E. Jr.; Mann, S.D.; Hall, D.R.

    1992-06-01

    This volume contains maps, well logging correlated to porosity and permeability, structural cross section, graph of production history, porosity vs. natural log permeability plot, detailed core log, paragenetic sequence and reservoir characterization sheet of the following fields in southwest Alabama: Appleton oil field; Barnett oil field; Barrytown oil field; Big Escambia Creek gas and condensate field; Blacksher oil field; Broken Leg Creed oil field; Bucatunna Creed oil field; Chappell Hill oil field; Chatom gas and condensate field; Choctaw Ridge oil field; Chunchula gas and condensate field; Cold Creek oil field; Copeland gas and condensate field; Crosbys Creed gas and condensate field; and East Barnett oil field. (AT)

  10. Simple Simulations of DNA Condensation

    SciTech Connect

    STEVENS,MARK J.

    2000-07-12

    Molecular dynamics simulations of a simple, bead-spring model of semiflexible polyelectrolytes such as DNA are performed. All charges are explicitly treated. Starting from extended, noncondensed conformations, condensed structures form in the simulations with tetravalent or trivalent counterions. No condensates form or are stable for divalent counterions. The mechanism by which condensates form is described. Briefly, condensation occurs because electrostatic interactions dominate entropy, and the favored Coulombic structure is a charge ordered state. Condensation is a generic phenomena and occurs for a variety of polyelectrolyte parameters. Toroids and rods are the condensate structures. Toroids form preferentially when the molecular stiffness is sufficiently strong.

  11. Detail of Bright Angel stone vault, containing condenser, Hoffman condensation ...

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

    Detail of Bright Angel stone vault, containing condenser, Hoffman condensation pump, Jennings vacuum heating pump, and misc. pipes and valves. - Grand Canyon Village Utilities, Grand Canyon National Park, Grand Canyon Village, Coconino County, AZ

  12. Optical properties of insulator-excitonic-semiconductor superlattices in the presence of inert layers

    NASA Astrophysics Data System (ADS)

    Cocoletzi, G. H.; Ramrez Perucho, A.; Luis Mochán, W.

    1991-11-01

    We study the optical properties of an insulator-excitonic-semiconductor superlattice in the presence of exciton-free inert layers on both surfaces of each semiconducting region. Generalized boundary conditions are applied at the interface between the inert layer and the active region, and the dispersion relation of the collective normal modes of an infinite superlattice is calculated near an excitonic transition. We also obtain the optical reflectance of a semi-infinite superlattice for p polarization. We present results for CdS layers using two well-known additional boundary conditions. Increasing the inert-layer thickness induces a blueshift and modifies the structure in the complex spectra. This structure is interpreted in terms of guided transverse- and longitudinal-wave resonances in the active excitonic layers.

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

    DOEpatents

    Ray, S.P.

    1986-04-15

    An improved inert electrode composition is suitable for use as an inert electrode in the production of metals such as aluminum by the electrolytic reduction of metal oxide or metal salt dissolved in a molten salt bath. The composition comprises one or more metal alloys and metal compounds which may include oxides of the metals comprising the alloy. The alloy and metal compounds are interwoven in a network which provides improved electrical conductivity and mechanical strength while preserving the level of chemical inertness necessary for such an electrode to function satisfactorily. The electrode composition further includes a metal compound dopant which will aid in controlling the thickness of a protective oxide layer on at least the bottom portion of an electrode made therefrom during use. 12 figs.

  14. Evaporation, Condensation, and Precipitation

    NSDL National Science Digital Library

    Miss Brown

    2009-10-21

    After completion of this project students should have an understanding of evaporation, condensation, and precipitation in the water cycle. Use the websites provided to answer the questions. Record your answers on the spreadsheet provided. Do you understand how the water cycle works? Begin by watching this short video about the water cycle.water cycle video Use the website to define condensation, precipitation, and evaporation?water cycle List the different types of precipitation from the site.types of precipitation Follow the directions to the experiment on this website to get a better understanding of how evaporation takes ...

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

    Microsoft Academic Search

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

    2008-01-01

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

  16. Initial condensate composition during asteroid impacts

    NASA Astrophysics Data System (ADS)

    de Niem, D.; Kührt, E.; Motschmann, U.

    2008-08-01

    A model has been developed for the chemical composition of early-time condensates forming during planetary impacts at velocities sufficient for complete evaporation of the impactor ( ˜22 kms). Hydrodynamics is approximated as hemispheric expansion of a chondritic impactor described with the help of a new semi-analytic equation of state. The gas phase is a mixture of a large number of molecular and mono-atomic species, whereas the Helmholtz free energy of the condensed phase is approximated as sum of a zero-temperature contribution and an Einstein-Debye solid for the thermal part. Interpolation of the free energy between the states of dense solids and molecular gases is used over the wide range of densities and pressures. Chemical equilibrium calculations, performed in a post-processing step, begin at conditions near the coexistence curve as obtained during hydrodynamic simulations, then the condensed phase contains 31 compound species, among them the most important oxides, sulphides, silicates as well as pure elements occurring in a liquid phase at sufficiently high temperature. The composition of the resulting liquid condensate in terms of major elements is compared to that of spinel inclusions in spherules found worldwide at the K-P boundary.

  17. How the dynamics of an ablation plume is affected by ambient gas ionisation

    NASA Astrophysics Data System (ADS)

    Bailini, A.; Ossi, P. M.

    2005-10-01

    The influence of inert gas ionisation on the expansion dynamics of a laser ablation plume propagating through an inert gas is studied. Charge transfer reactions between ionised ablated species and gas neutrals lead to the formation of a charged layer of ionised gas atoms in contact with the plume expansion front. The energy lost by fast ablated ions when the plume is slowed down is calculated. For the exemplary carbon ablation in helium and argon atmospheres, where background gas ionisation plays a different role, model predictions agree with the observed microstructural differences of deposited films.

  18. A steam inerting system for hydrogen disposal for the Vandenberg Shuttle

    NASA Technical Reports Server (NTRS)

    Belknap, Stuart B.

    1988-01-01

    A two-year feasibility and test program to solve the problem of unburned confined hydrogen at the Vandenberg Space Launch Complex Six (SLC-6) during Space Shuttle Main Engine (SSME) firings is discussed. A novel steam inerting design was selected for development. Available sound suppression water is superheated to flash to steam at the duct entrance. Testing, analysis, and design during 1987 showed that the steam inerting system (SIS) solves the problem and meets other flight-critical system requirements. The SIS design is complete and available for installation at SLC-6 to support shuttle or derivative vehicles.

  19. A Local Condensation Analysis Representing Two-phase Annular Flow in Condenser/radiator Capillary Tubes

    NASA Technical Reports Server (NTRS)

    Karimi, Amir

    1991-01-01

    NASA's effort for the thermal environmental control of the Space Station Freedom is directed towards the design, analysis, and development of an Active Thermal Control System (ATCS). A two phase, flow through condenser/radiator concept was baselined, as a part of the ATCS, for the radiation of space station thermal load into space. The proposed condenser rejects heat through direct condensation of ATCS working fluid (ammonia) in the small diameter radiator tubes. Analysis of the condensation process and design of condenser tubes are based on the available two phase flow models for the prediction of flow regimes, heat transfer, and pressure drops. The prediction formulas use the existing empirical relationships of friction factor at gas-liquid interface. An attempt is made to study the stability of interfacial waves in two phase annular flow. The formulation is presented of a stability problem in cylindrical coordinates. The contribution of fluid viscosity, surface tension, and transverse radius of curvature to the interfacial surface is included. A solution is obtained for Kelvin-Helmholtz instability problem which can be used to determine the critical and most dangerous wavelengths for interfacial waves.

  20. From High-Temperature Gas-Cooled Reactors to Gas-Cooled Fast Breeder Reactors

    Microsoft Academic Search

    R. H. Simon; G. J. Schlueter

    1973-01-01

    The evolution of gas-cooled reactors is described and the advantages of helium as a reactor coolant stemming from its inertness and the fact that it is a single-phase coolant are discussed. The High-Temperature Gas-Cooled Reactor (HTGR) forms the basis for the current design of a Gas-Cooled Fast Breeder Reactor (GCFR). The extensive use of existing HTGR technology and the similarities

  1. Strategies in Optimizing Condensate Return

    E-print Network

    Bloom, D.

    Optimizing condensate return for reuse as boiler feedwater is often a viable means of reducing fuel costs and improving boiler system efficiency. As more condensate is returned, less makeup is required and savings on water and water treatment costs...

  2. Scattering of neutrons on a Bose condensate

    NASA Astrophysics Data System (ADS)

    Baranov, D. B.; Kozlov, Z. A.; Siurakshina, L. A.; Yarunin, V. S.

    1999-02-01

    The spectrum of noncondensate excitations in neutron scattering on bosons is obtained in the framework of the Bogoliubov models both for liquid 4He and a dilute gas. The problem is solved using a path-integral representation of the partition function of the system. We describe the influence of scattering of neutrons on a Bose condensate in a stationary (time-independent) picture in the Gibbs equilibrium ensemble. This influence is a stationary boson response, and it depends on the initial neutron momentum k, transfer momentum p, and the neutron-boson interaction , which is related to the scattering length. The contribution of the neutrons to the initial Bogoliubov spectrum is found to be important for quasi-elastic scattering on the noncondensate, while the contribution of deep inelastic scattering is small; no contribution from elastic scattering on the Bose condensate is found. In the case of liquid Helium, the response is unlikely to be observable for all values p. On the other hand, for a gas one may expect a visible effect, in particular for a small momentum transfer p and a small density of the Bose condensate .

  3. Cloud Condensation Nuclei Sizes

    Microsoft Academic Search

    J. G. Hudson; S. Mishra

    2006-01-01

    The sizes of cloud condensation nuclei (CCN) can be determined by first passing an aerosol sample through a differential mobility analyzer (DMA) and then to a CCN counter or spectrometer (i.e., Hudson 1989), which provides a mean value of the critical supersaturation (Sc) of the particles. By sequentially dialing in several different DMA sizes a relationship between dry particle size

  4. Steam and Condensate Systems 

    E-print Network

    Yates, W.

    1979-01-01

    STEAM AND CONDENSATE SYSTEM Wesley Yates Yarway Corporation Houston, Texas In the late 60's and early 70's oil was plentiful and steam was relatively inexpen sive. The switch to low sulphur fuel oil and the oil embargo suddenly changed the pic...

  5. Asymmetric condensed dark matter

    E-print Network

    Anthony Aguirre; Alberto Diez-Tejedor

    2015-02-25

    We explore the viability of a boson dark matter candidate with an asymmetry between the number densities of particles and antiparticles. A simple thermal field theory analysis confirms that, under certain general conditions, this component would develop a Bose-Einstein condensate in the early universe that, for appropriate model parameters, could survive the ensuing cosmological evolution until now. The condensation of a dark matter component in equilibrium with the thermal plasma is a relativistic process, hence the amount of matter dictated by the charge asymmetry is complemented by a hot relic density frozen out at the time of decoupling. Contrary to the case of ordinary WIMPs, dark matter particles in a condensate can be very light, $10^{-22}\\,{\\rm eV} \\lesssim m \\lesssim 10^2\\,{\\rm eV}$; the lower limit arises from constraints on small-scale structure formation, while the upper bound ensures that the density from thermal relics is not too large. Big-Bang nucleosynthesis constrains the temperature of decoupling to the scale of the QCD phase transition or above. This requires large dark matter-to-photon ratios and very weak interactions with standard model particles. Finally, we argue that a given boson particle that was in thermal equilibrium in the early universe may be in a condensate, or in the form of thermal relics, but we cannot have a combination of both contributing significantly to the mass density today.

  6. Re-Condensation

    E-print Network

    Bhatia, P.; Kozman, T.

    2004-01-01

    When steam transfers its heat in a manufacturing process or heat exchanger, it may revert to a liquid phase called condensate. This paper presents a method to help certain manufacturing and petro-chemical companies to save energy costs by returning their...

  7. Re-Condensation 

    E-print Network

    Bhatia, P.; Kozman, T.

    2004-01-01

    When steam transfers its heat in a manufacturing process or heat exchanger, it may revert to a liquid phase called condensate. This paper presents a method to help certain manufacturing and petro-chemical companies to save energy costs by returning their...

  8. Soft condensed matter physics

    Microsoft Academic Search

    T. C. Lubensky

    1997-01-01

    Soft condensed matter physics is the study of materials, such as fluids, liquid crystals, polymers, colloids and emulsions, that are “soft” to the touch. This article will review some properties, such as the dominance of entropy, that are unique to soft materials and some properties such as the interplay between broken-symmetry, dynamic mode structure and topological defects that are common

  9. Condensed-Matter Physics.

    ERIC Educational Resources Information Center

    Hirsch, Jorge E.; Scalapino, Douglas J.

    1983-01-01

    Discusses ways computers are being used in condensed-matter physics by experimenters and theorists. Experimenters use them to control experiments and to gather and analyze data. Theorists use them for detailed predictions based on realistic models and for studies on systems not realizable in practice. (JN)

  10. Condensed matter physics journals

    Microsoft Academic Search

    R. Todorov

    1983-01-01

    On the basis of a citation\\/reference criterion, 20 core journals are selected in the field of condensed matter physics. Citation data and indicators from 1980Journal Citation Reports reveal their different characteristic features such as applied orientation, communication function and longevity. The manually obtained data for the core journals are written into a matrix in order to determine an appropriate ranking

  11. Condensed Matter Physics

    Microsoft Academic Search

    I Strzalkowski

    2000-01-01

    Condensed matter physics constitutes nowadays an enormous field of knowledge. To write a good textbook covering all main topics in that field in a suitable way and in a reasonable volume is very hard indeed. I believe Michael Marder has achieved this goal with great success. The text is arranged in six parts. Part I describes the atomic structure of

  12. I.I. Rabi Prize Lecture: Bose-Einstein condensates - matter with laser-like properties

    NASA Astrophysics Data System (ADS)

    Ketterle, Wolfgang

    1997-04-01

    Several studies of Bose-Einstein condensation in a dilute gas of sodium atoms have been performed. Bose-condensates were produced by evaporative cooling in a tightly-confining magnetic "cloverleaf" trap and observed either by absorption imaging or non-destructive phase contrast imaging. We have observed the formation of a Bose condensate and low-lying collective excitations. An rf output coupler allowed the controlled extraction of multiple pulses of atoms from a trapped Bose condensate. Two condensates were produced by evaporative cooling in a double-well potential. When the condensates were released and overlapped, high contrast interference was observed proving the coherence of the condensates. The controlled extraction of coherent atoms is a rudimentary realization of an atom laser.

  13. DEPARTMENT OF CONDENSED MATTER PHYSICS

    E-print Network

    Shyamasundar, R.K.

    DEPARTMENT OF CONDENSED MATTER PHYSICS AND MATERIALS SCIENCE Welcome to the Department of Condensed Matter Physics and Materials Science (CMPMS) at TIFR! Research in CMPMS asks questions about j a y a r a g h a v a n #12;Condensed Matter Physics & Materials Science Research areas A common

  14. Physics 232 Condensed Matter Physics

    E-print Network

    Young, A. Peter

    1 Physics 232 Condensed Matter Physics Instructor: Peter Young Office: 212 ISB Telephone: 459://apyoung.com/232 TOPICS This course on condensed matter physics will cover three areas: · magnetism, · optical physics such as Condensed Matter Physics by M. Mardar Solid State Physics by N. Ashroft and N. D. Mermin

  15. Response of a Bose-Einstein condensate of dipole excitons to static and dynamic perturbations

    NASA Astrophysics Data System (ADS)

    Batyev, E. G.; Kovalev, V. M.; Chaplik, A. V.

    2014-07-01

    Studies of the interaction of a Bose-Einstein condensate of two-dimensional spatially indirect excitons with the static fields of impurities, surface acoustic waves, and elementary excitations of a degenerate electron gas have been reviewed. The effects of screening of charged impurities and absorption of a Bleustein-Gulyaev surface acoustic wave by an exciton condensate have been considered. Friedel oscillations of the exciton density in a hybrid electron-exciton system, which consists of spatially separated layers of condensed exciton gas and degenerate electron gas, have been studied. The lifetimes of quasiparticle excitations (electrons, plasmons, and bogolons) in the hybrid system have been calculated. The contributions to the effects under study from condensate and above-condensate particles have been determined. The properties of an excitonic insulator have been analyzed within the Bardeen-Cooper-Schrieffer model with a built-in dissipation-free current.

  16. Reduction of combustion noise and instabilities using porous inert material with a swirl-stabilized burner

    NASA Astrophysics Data System (ADS)

    Sequera, Daniel

    Combustion instabilities represent a major problem during operation of power generation systems that can lead to costly shutdown. Combustion instabilities are self excited large amplitude pressure oscillations caused by the coupling of unsteady heat release and acoustic modes of the combustor. These oscillations cause fluctuating mechanical loads and fluctuating heat transfer that can result in catastrophic premature failure of components. Combustion noise, a significant source of noise in gas turbines, can lead to combustion instabilities. Combustion noise and instabilities are different phenomena; however, they both occur due to unsteady heat release of turbulent flames that excites acoustic modes of the combustor. The instabilities self excite when flame adds energy to the acoustic field at a faster rate than it can dissipate it. Swirl-stabilized combustion and porous inert medium (PIM) combustion are two methods that have extensively been used, although independently, for flame stabilization. In this study, the two concepts are combined so that PIM serves as a passive device to mitigate combustion noise and instabilities. A PIM insert is placed within the lean premixed, swirl-stabilized combustor to affect the turbulent flow field reducing combustion noise. This study is the first step for eventual implementation in liquid fuel systems. After presenting the concept, a numerical investigation of the changes in the mean flow field caused by the PIM is presented. Changes in the flow field can be beneficial for noise reduction by optimizing the geometric parameters of the PIM. Next, atmospheric pressure experiments were conducted at low reactant inlet velocity (<10 m/s) and low reactant inlet temperature (<120°C) to investigate effect of PIM parameters on sound pressure level (SPL), and CO and NOx emissions. Surface and interior combustion modes were identified and PIM geometric parameters were optimized. Next, a laboratory facility to conduct experiments at high reactant inlet velocity, high inlet air temperature, and high pressure was designed and developed. Results show that the porous insert substantially reduces combustion noise for a range of operating conditions. Moreover, experiments show that the porous insert can mitigate combustion instabilities without adversely affecting CO and NOx emissions.

  17. Sidestream condensate polishing for PWRs

    SciTech Connect

    Shor, S.W.W.; Yim, S.L.; Rios, J.; Liu, J.

    1986-06-01

    Condensate polishers are used in power plant condensate system to remove both particulate matter and ionized corrodents. Their conventional location is just downstream of the hotwell pumps (condensate pumps). Most polisher installations have enough flow capacity to polish 100% of the condensate. This inline configuration has some disadvantage, including a flow that varies with unit load and tends to disturb the polisher beds and reduce their effectiveness, and a potential for interrupting flow to the feedwater pumps. An alternate arrangement where water is extracted from either the condenser or the condensate system, polished and returned to the system, has been used in a few plants. Three different ways of doing this have been used: divide the condenser hotwell into two parts, one of which receives condensate from the tube bundles and the other of which is sheltered. Take unpolished condensate from the first part, purify it and return it to the other part from which the condensate pumps take suction; take unpolished condensate from one end of a divided header on the suction side of the hotwell pumps and after polishing it return it to the other end; and take unpolished condensate from a header on the discharge side of the condensate pumps, purify it and return it to the condensate system a short distance downstream. The three variants are analyzed in this report. It is concluded that the variant where the connections are on the discharge side of the condensate pumps is the most desirable for retrofitting, in all cases being far easier to retrofit than an inline polisher. In many cases it will be most desirable for new construction.

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

    E-print Network

    Paris-Sud XI, Université de

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

  19. The ethics of placebo-controlled trials: a comparison of inert and active placebo controls.

    PubMed

    Edward, Sarah J L; Stevens, Andrew J; Braunholtz, David A; Lilford, Richard J; Swift, Teresa

    2005-05-01

    Because of the recent and controversial example of sham surgery for the evaluation of fetal tissue transplants for Parkinson's disease, there is renewed interest in the ethics of using "active" placebos in surgical trials, where otherwise there are no inert procedures available, and in pharmacological trials, where there are inert substances, but where patients may guess to which arm they have been allocated. This paper seeks to clarify the ethical arguments surrounding the use of active placebos in trials, and to set up a notation for assessing the ethics of trials more generally. We first establish an framework by which ethics committees can analyze such trials. We examine (1) the scientific value of the research; (2) the expected risks and benefits to individual patients, and (3) the voluntary nature of consent. We then contrast the implications of this framework for inert and active placebo-controlled trials, respectively. In particular, we analyze their relative expected utility using three main utility factors, namely, treatment effects, placebo effects, and altruism. We conclude that, when the intervention is already widely available, active placebo trials rely more heavily on altruism than do inert placebo trials and, when the intervention is restricted, this excess reliance may not be needed. What our analysis provides is the explicit justification for the apparent caution of Institutional Review Boards or ethics committees when reviewing sham operations, especially when the expected harm is not trivial and the risk of exploitation is high. PMID:15827854

  20. Improved scaling laws for stage inert mass of space propulsion systems. Volume 1: Summary

    NASA Technical Reports Server (NTRS)

    1971-01-01

    Summarized is a study which satisfies the need for improved scaling laws for stage inert mass of space propulsion systems. The resulting laws are applicable to current and future vehicle systems and designs for a comprehensive spectrum of anticipated planetary missions.

  1. Conditional statistics of inert droplet effects on turbulent combustion in reacting mixing layers

    Microsoft Academic Search

    J. Xia; K. H. Luo

    2009-01-01

    Direct numerical simulation (DNS) of turbulent reacting mixing layers laden with evaporating inert droplets is used to assess the droplet effects in the context of the conditional moment closure (CMC) for multiphase turbulent combustion. The temporally developing mixing layer has an initial Reynolds number of 1000 based on the vorticity thickness with more than 16 million Lagrangian droplets traced. An

  2. Transmutation of actinides in inert-matrix fuels: fabrication studies and modelling of fuel behaviour

    NASA Astrophysics Data System (ADS)

    Konings, R. J. M.; Bakker, K.; Boshoven, J. G.; Hein, H.; Huntelaar, M. E.; van der Laan, R. R.

    1999-08-01

    A review of the ongoing research of inert-matrix fuels for the transmutation of actinides is given. Three fabrication routes are described, co-precipitation (CPP), low-impact mixing of powders (LMP) and mixing of particles and powders (MPP). These methods have been tested for various combinations of actinide host materials and inert matrices. Most attention is given to a fuel concept consisting of an actinide-containing host phase and spinel as the inert matrix. To understand the phase relations and melting behaviour of this hybrid fuel type the binary phase diagrams in the system (Zr,Y,Pu)O 2 + MgAl 2O 4 are being modelled and some results are presented. In addition, the thermal behaviour of MgAl 2O 4-based inert-matrix fuels is investigated. The thermal conductivity of polycrystalline spinel is measured and in-pile temperature measurements of an UO 2 + MgAl 2O 4 target are analysed.

  3. Modeling separation of proteins by inert core adsorbent in a batch adsorber

    Microsoft Academic Search

    Ping Li; Guohua Xiu; Alirio E. Rodrigues

    2003-01-01

    Adsorption\\/desorption kinetics of protein on the binding ligand of inert core adsorbent in a batch adsorber is analyzed theoretically for Langmuir isotherm coupled with the intraparticle diffusion and film mass transfer resistances. For the two limiting cases of Langmuir isotherm, there are analytical solutions. New analytical solutions are derived for Henry isotherm, and the analytical solution of shrinking core model

  4. Quick look analysis of an emergency separation for ALT captive-inert flight 1

    NASA Technical Reports Server (NTRS)

    Glenn, G. M.; Seale, R. H.

    1977-01-01

    Emergency separation capability for the landing configuration of ALT Captive Inert Flight Number One was investigated. The quick look analysis confirms emergency separation capability under nominal conditions for the ALT landing configuration. The recommended emergency separation procedure under those conditions is not applicable to all ALT configurations.

  5. YOUNG INFANTS’ REASONING ABOUT PHYSICAL EVENTS INVOLVING INERT AND SELF-PROPELLED OBJECTS

    PubMed Central

    Luo, Yuyan; Kaufman, Lisa; Baillargeon, Renée

    2009-01-01

    The present research examined whether 5- to 6.5-month-old infants would hold different expectations about various physical events involving a box after receiving evidence that it was either inert or self-propelled. Infants were surprised if the inert but not the self-propelled box: reversed direction spontaneously (Experiment 1); remained stationary when hit or pulled (Experiments 3 and 3A); remained stable when released in midair or with inadequate support from a platform (Experiment 4); or disappeared when briefly hidden by one of two adjacent screens (the second screen provided the self-propelled box with an alternative hiding place; Experiment 5). On the other hand, infants were surprised if the inert or the self-propelled box appeared to pass through an obstacle (Experiment 2) or disappeared when briefly hidden by a single screen (Experiment 5). The present results indicate that infants as young as 5 months of age distinguish between inert and self-propelled objects and hold different expectations for physical events involving these objects, even when incidental differences between the objects are controlled. These findings are consistent with the proposal by Gelman (1990), Leslie (1994), and others that infants endow self-propelled objects with an internal source of energy. Possible links between infants’ concepts of self-propelled object, agent, and animal are also discussed. PMID:19232579

  6. The validation of a thermal battery model using electrically-inert and active batteries

    Microsoft Academic Search

    John Knight; I. McKirdy

    1990-01-01

    Physical property data on thermal battery component materials were obtained from the matching of model simulations to experimental thermocouple responses of inert batteries, here defined as dummy batteries. This has been done for some thermal battery designs by: (i) building and testing a series of 30 dummy batteries fitted with internal thermocouples, whose stacks consisted merely of pyrotechnic pellets alternating

  7. Development of a modified chemical inertness test method for refillable pet bottle material

    Microsoft Academic Search

    Aristoula G. Karamani; Panagiotis G. Demertzis; Konstantoula Akrida-Demertzi

    2002-01-01

    Refillable PET containers offer great advantages from an ecological point of view, i.e., to reduce waste from packaging materials. A major concern is the potential public health risks of PET refillable bottles due to possible misuse. In this study, a modified method for determining the chemical inertness of PET bottles involving the interaction of strips from bottle walls with a

  8. Sensory characterization of polyester-based bottle material inertness using threshold odour number determination

    Microsoft Academic Search

    Heléne Widén; Gunnar Hall

    2007-01-01

    Refillable polyester bottles, for example polyethylene terephthalate (PET) bottles, are known to interact with chemicals. Aroma compounds from a product can be absorbed by the bottle material, remain after washing and remigrate when the bottle is reused, resulting in off-flavour of the new product. A certified reference material has recently been approved with which the chemical and sensory inertness of

  9. PAPER www.rsc.org/loc | Lab on a Chip Teflon films for chemically-inert microfluidic valves and pumps

    E-print Network

    Manalis, Scott

    800600h We present a simple method for fabricating chemically-inert Teflon microfluidic valves and pumps in glass microfluidic devices. These structures are modeled after monolithic membrane valves and pumpsPAPER www.rsc.org/loc | Lab on a Chip Teflon films for chemically-inert microfluidic valves

  10. Experimental investigation of CO2 condensation process using cryogen

    NASA Astrophysics Data System (ADS)

    Lee, Cheonkyu; Yoo, Junghyun; Lee, Jisung; Park, Hana; Jeong, Sangkwon

    2014-01-01

    Carbon dioxide (CO2) is one of the dominant gas molecules that causes greenhouse effect, i.e. global warming. Numerous studies have been carried out to regulate the emission of CO2 to reduce greenhouse gas. The liquid CO2 is a convenient form of transportation compared to high-pressurized gaseous CO2. Therefore, the direct liquefaction mechanism of CO2 at low temperature draws technical attention recently. In particular, cold thermal energy of Liquefied Natural Gas (LNG) could be a candidate to condense gaseous CO2, especially in the LNG powered ship. In this paper, the detailed direct condensation process of CO2 using LN2 with intermittent solidification is investigated. Pressurized CO2 at 600 kPa is directly liquefied in a vessel by liquid nitrogen which is supplied into the coiled tube heat exchanger inside the CO2 vessel. The heat exchanger temperature is controlled from 130 K to 205 K to regulate the solidification and sublimation of CO2 by duty control with cryogenic solenoid valve. The characteristics of CO2 condensation process with cryogen are analyzed from the measurement results. The results show that the solidification causes the significant degradation of CO2 condensation heat transfer. Finally, the condensation rate with and without solidification is compared.

  11. Molecular fossils in Cretaceous condensate from western India

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Sharmila; Dutta, Suryendu; Dutta, Ratul

    2014-06-01

    The present study reports the biomarker distribution of condensate belonging to the early Cretaceous time frame using gas chromatography-mass spectrometry (GC-MS). The early Cretaceous palaeoenvironment was inscribed into these molecular fossils which reflected the source and conditions of deposition of the condensate. The saturate fraction of the condensate is characterized by normal alkanes ranging from n-C9 to n-C29 (CPI-1.13), cycloalkanes and C14 and C15 sesquiterpanes. The aromatic fraction comprises of naphthalene, phenanthrene, their methylated derivatives and cyclohexylbenzenes. Isohexylalkylnaphthalenes, a product of rearrangement process of terpenoids, is detected in the condensate. Several aromatic sesquiterpenoids and diterpenoids have been recorded. Dihydro- ar-curcumene, cadalene and ionene form the assemblage of sesquiterpenoids which are indicative of higher plant input. Aromatic diterpenoid fraction comprises of simonellite and retene. These compounds are also indicative of higher plants, particularly conifer source which had been a predominant flora during the Cretaceous time.

  12. Production of smoke particles condensed from K+N2O or Zn+O2 vapor

    NASA Astrophysics Data System (ADS)

    Hecht, J.; Norton, M. A.

    1981-04-01

    K and Zn metal were evaporated in an inert gas and oxidant atmosphere at pressures of 1-50 Torr. The resultant smoke was analyzed as to size and composition by light scattering and electron microscopy techniques. The formation of K2O and ZnO particles was consistent with previous work on Na2O particle formation.

  13. Refractory metal nuggets within presolar graphite: First condensates from a circumstellar environment

    E-print Network

    Refractory metal nuggets within presolar graphite: First condensates from a circumstellar) Abstract­Transmission electron microscope (TEM) investigations have revealed Os, Ru, Mo-rich refractory that these are direct condensates from the gas, rather than forming later by exsolution. The presolar refractory metal

  14. Experimental studies of the vapor phase nucleation of refractory compounds. VI. The condensation of sodium

    Microsoft Academic Search

    Daniel M. Martínez; Frank T. Ferguson; Richard H. Heist; Joseph A. Nuth

    2005-01-01

    In this paper we discuss the condensation of sodium vapor and the formation of a sodium aerosol as it occurs in a gas evaporation condensation chamber. A one-dimensional model describing the vapor transport to the vapor\\/aerosol interface was employed to determine the onset supersaturation, in which we assume the observed location of the interface is coincident with a nucleation rate

  15. Gas sensors based on Paschen's law using carbon nanotubes as electron emitters

    Microsoft Academic Search

    S J Kim

    2006-01-01

    In the case of typical gas sensors responding by gas adsorption on the surface, it is very difficult to detect inert gases which have low chemical adsorption energies under normal conditions. Carbon nanotubes (CNTs) are well known as electron emitters in applications like field emission displays. In this work, we fabricate a physical gas sensor (or vacuum sensor) using CNTs

  16. Respiratory and plumage gas volumes in unrestrained diving ducks ( Aythya affinis)

    Microsoft Academic Search

    Richard Stephenson

    1995-01-01

    Closed-circuit plethysmography and inert gas equilibration analysis were used to measure the volumes of gas in the respiratory system and plumage at the end of voluntary dives in unrestrained lesser scaup (Aythya affinis). Total (respiratory plus plumage) gas volumes were measured by helium dilution and estimated from body mass, body tissue density and buoyant force. These two techniques yielded results

  17. Gravitational vacuum condensate stars

    PubMed Central

    Mazur, Pawel O.; Mottola, Emil

    2004-01-01

    A new final state of gravitational collapse is proposed. By extending the concept of Bose–Einstein condensation to gravitational systems, a cold, dark, compact object with an interior de Sitter condensate pv = -?v and an exterior Schwarzschild geometry of arbitrary total mass M is constructed. These regions are separated by a shell with a small but finite proper thickness ? of fluid with equation of state p = +?, replacing both the Schwarzschild and de Sitter classical horizons. The new solution has no singularities, no event horizons, and a global time. Its entropy is maximized under small fluctuations and is given by the standard hydrodynamic entropy of the thin shell, which is of the order kB?Mc/, instead of the Bekenstein–Hawking entropy formula, SBH = 4?kBGM2/c. Hence, unlike black holes, the new solution is thermodynamically stable and has no information paradox. PMID:15210982

  18. U.S. crude oil, natural gas, and natural gas liquids reserves 1997 annual report

    SciTech Connect

    Wood, John H.; Grape, Steven G.; Green, Rhonda S.

    1998-12-01

    This report presents estimates of proved reserves of crude oil, natural gas, and natural gas liquids as of December 31, 1997, as well as production volumes for the US and selected States and State subdivisions for the year 1997. Estimates are presented for the following four categories of natural gas: total gas (wet after lease separation), nonassociated gas and associated-dissolved gas (which are the two major types of wet natural gas), and total dry gas (wet gas adjusted for the removal of liquids at natural gas processing plants). In addition, reserve estimates for two types of natural gas liquids, lease condensate and natural gas plant liquids, are presented. Also included is information on indicated additional crude oil reserves and crude oil, natural gas, and lease condensate reserves in nonproducing reservoirs. A discussion of notable oil and gas exploration and development activities during 1997 is provided. 21 figs., 16 tabs.

  19. Isotope Enrichment by Laser Stimulation Causing Condensation Repression

    SciTech Connect

    Kunze, Jay F.; Islam, K.T.S.; Nieschmidt, Ernest [Idaho State University, 921 South 8th Avenue, Pocatello, Idaho 83209 (United States)

    2002-07-01

    Sulfur isotopes in SF{sub 6} molecules have been enriched, in a laboratory experiment, using tuned laser radiation to excite a particular sulfur isotopic molecule and inhibit its condensation on the cooled annulus inside of the chamber. The evidence of enrichment was determined by examining the residual gas with a Fourier Transform infrared Spectrometer. The enrichment was observed during a transient experiment in which the temperature of the condensing surface was gradually decreased, and gas pressure of the SF{sub 6} molecules was in the range of 8 Torr (0.01 atmospheres). These results show that excitation to a single excited level can create differential rates of condensation so as to achieve an enrichment factor of approximately 2.0 in a single stage. (authors)

  20. Bose-Einstein Condensation

    SciTech Connect

    El-Sherbini, Th.M. [Physics Department, Faculty of Science, Cairo University, Giza (Egypt)

    2005-03-17

    This article gives a brief review of Bose-Einstein condensation. It is an exotic quantum phenomenon that was observed in dilute atomic gases for the first time in 1995. It exhibits a new state of matter in which a group of atoms behaves as a single particle. Experiments on this form of matter are relevant to many different areas of physics- from atomic clocks and quantum computing to super fluidity, superconductivity and quantum phase transition.